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Keywords = non-mevalonate pathway

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17 pages, 1816 KiB  
Article
The Diverse Binding Modes Explain the Nanomolar Levels of Inhibitory Activities Against 1-Deoxy-d-Xylulose 5-Phosphate Reductoisomerase from Plasmodium falciparum Exhibited by Reverse Hydroxamate Analogs of Fosmidomycin with Varying N-Substituents
by Sana Takada, Mona A. Abdullaziz, Stefan Höfmann, Talea Knak, Shin-ichiro Ozawa, Yasumitsu Sakamoto, Thomas Kurz and Nobutada Tanaka
Molecules 2025, 30(1), 72; https://doi.org/10.3390/molecules30010072 - 28 Dec 2024
Viewed by 372
Abstract
It is established that reverse hydroxamate analogs of fosmidomycin inhibit the growth of Plasmodium falciparum by inhibiting 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), the second enzyme of the non-mevalonate pathway, which is absent in humans. Recent biochemical studies have demonstrated that novel reverse [...] Read more.
It is established that reverse hydroxamate analogs of fosmidomycin inhibit the growth of Plasmodium falciparum by inhibiting 1-deoxy-d-xylulose 5-phosphate reductoisomerase (DXR), the second enzyme of the non-mevalonate pathway, which is absent in humans. Recent biochemical studies have demonstrated that novel reverse fosmidomycin analogs with phenylalkyl substituents at the hydroxamate nitrogen exhibit inhibitory activities against PfDXR at the nanomolar level. Moreover, crystallographic analyses have revealed that the phenyl moiety of the N-phenylpropyl substituent is accommodated in a previously unidentified subpocket within the active site of PfDXR. In this study, the crystal structures of PfDXR in complex with a series of reverse N-phenylalkyl derivatives of fosmidomycin were determined to ascertain whether the high inhibitory activities of the derivatives are consistently attributable to the utilization of the subpocket of PfDXR. While all reverse fosmidomycin derivatives with an N-substituted phenylalkyl group exhibit potent inhibitory activity against PfDXR, the present crystal structure analyses revealed that their binding modes to the PfDXR are not uniform. In these compounds, the nanomolar inhibitory activities appear to be driven by binding modes distinct from that observed for the inhibitor containing the N-phenylpropyl group. The structural information obtained in this study will provide a basis for further design of fosmidomycin derivatives. Full article
(This article belongs to the Special Issue Synthesis and Evaluation of Bioactivity of Enzyme Inhibitors)
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Figure 1
<p>The inhibitors utilized in this study for crystallographic analyses in complex with <span class="html-italic">Pf</span>DXR. The IC<sub>50</sub> values of the inhibitors against the enzymatic activity of <span class="html-italic">Pf</span>DXR from our recent study [<a href="#B24-molecules-30-00072" class="html-bibr">24</a>] are provided in parentheses. The MAMK89 analogs with the following structural modifications were chosen for the crystal structure analyses: (i) alterations in the linker length (yellow) and (ii) introduction of substituents to the terminal phenyl moiety (light blue) of the <span class="html-italic">N</span>-phenylpropyl group.</p>
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<p>The crystal structures of <span class="html-italic">Pf</span>DXR in complex with the <span class="html-italic">N</span>-phenylalkyl fosmidomycin derivatives. (<b>A</b>) The overall structure of the MAMK89–quaternary complex of <span class="html-italic">Pf</span>DXR. One subunit is shown in a ribbon model, and the other in a surface model. The substrate/inhibitor binding site of each subunit is indicated by red squares. The bound MAMK89 and NADPH molecules are shown in space-filling models and colored magenta and yellow, respectively. (<b>B</b>) MAMK150–quaternary complex (yellow and pale yellow). (<b>C</b>) MAMK218–ternary complex (green and pale green). (<b>D</b>) MAMK251–ternary complex (red and pale red). (<b>E</b>) MAMK433–quaternary complex (light blue and pale light blue). (<b>F</b>) MAMK431–quaternary complex (dark blue and pale dark blue). In panels (<b>B</b>–<b>F</b>), the MAMK89–quaternary complex (sky blue and pale sky blue) is also shown for comparison.</p>
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<p>The superpositions of the binding modes of the <span class="html-italic">N</span>-phenylalkyl fosmidomycin derivatives in the active site of <span class="html-italic">Pf</span>DXR. Inhibitor molecules are colored in accordance with <a href="#molecules-30-00072-f002" class="html-fig">Figure 2</a>. MAMK89 is depicted as a ball-and-stick model, while the remaining inhibitors are illustrated as stick models. (<b>A</b>) A comparison of linker length. The <span class="html-italic">N</span>-phenylalkyl groups of MAMK89 (sky blue) and MAMK218 (green) assume bent conformations and occupy the subpocket (indicated by a dashed ellipsoid, magenta), whereas MAMK150 (yellow), MAMK218 (green), and MAMK251 (red) adopt curved conformations. (<b>B</b>) A comparison of the phenyl moiety with/without <span class="html-italic">para</span>-substituent. The <span class="html-italic">N</span>-phenylpropyl group of MAMK89 (sky blue) assumes a bent conformation and is bound within the subpocket (indicated by a dashed ellipsoid, magenta), whereas MAMK433 (light blue) and MAMK431 (dark blue) adopt curved conformations. (<b>C</b>) View of the molecules in (<b>A</b>) from a direction rotated by 50° around the <span class="html-italic">x</span>-axis. (<b>D</b>) View of the molecules in (<b>B</b>) from a direction rotated by 50° around the <span class="html-italic">x</span>-axis.</p>
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<p>A surface representation of the subpocket in the active site of the MAMK89–quaternary complex of <span class="html-italic">Pf</span>DXR. The <span class="html-italic">para</span> position of the phenyl moiety of the <span class="html-italic">N</span>-phenylpropyl group of MAMK89 is shown in the center and indicated by a dashed ellipsoid depicted in magenta. The bound water molecules located at the rear of the subpocket are depicted in green, and potential hydrogen bonds surrounding these molecules are indicated by dashed lines.</p>
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<p>The conformational variation of the main-chain carbonyl group of Asp359 located at the entrance to the subpocket within the active site of <span class="html-italic">Pf</span>DXR. The MAMK89–quaternary and MAMK251–ternary complexes are illustrated and colored in accordance with the conventions in <a href="#molecules-30-00072-f002" class="html-fig">Figure 2</a>. The subpocket is indicated by a dashed ellipsoid depicted in magenta. The carbonyl groups of Asp359 adopt upward and downward conformations, respectively, in the case of the MAMK89 and MAMK251 complexes.</p>
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10 pages, 1746 KiB  
Article
Association of Wild-Type TP53 with Downregulation of Lovastatin Sensitivity in Human Non-Small Cell Lung Cancer Cells
by Yu-Yao Chang, Tsung-Ying Yang and Gwo-Tarng Sheu
Curr. Issues Mol. Biol. 2024, 46(9), 10130-10139; https://doi.org/10.3390/cimb46090604 - 13 Sep 2024
Cited by 1 | Viewed by 938
Abstract
Statins inhibit 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway, and reduce cholesterol synthesis. They also have been demonstrated to improve prognosis in patients with various cancers, suggesting a potential anti-cancer effect of statins. However, there is no consensus on the [...] Read more.
Statins inhibit 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the rate-limiting enzyme of the mevalonate pathway, and reduce cholesterol synthesis. They also have been demonstrated to improve prognosis in patients with various cancers, suggesting a potential anti-cancer effect of statins. However, there is no consensus on the molecular targets of statins for their anti-cancer effects. Docetaxel (DOC) is a microtubule-stabilizing agent currently used as a chemotherapeutic drug in several cancers, including lung cancer. Interestingly, the anti-cancer effects of either drug that are related to abnormal or wild-type TP53 gene have been implied. Therefore, the drug sensitivity of DOC and lovastatin in human lung cancer cells was evaluated. We found that H1355 (mutant TP53-E285K), CL1 (mutant TP53-R248W), and H1299 (TP53-null) human non-small cell lung cancer cells were more sensitive to lovastatin than A549 and H460 cells expressing wild-type TP53. Conversely, A549 and H460 cells showed higher sensitivity to DOC than H1299 and CL1 cells, as demonstrated by the MTT assay. When endogenous TP53 activity was inhibited by pifithrin-α in A549 and H460 cells, lovastatin sensitivities significantly increased, and cancer cell viabilities markedly reduced. These results indicate that TP53 status is associated with the anti-cancer effect of statins in human lung cancer cells. Mutated or null TP53 status is correlated with higher statin sensitivity. Furthermore, DOC-resistant H1299 (H1299/D8) cells showed significant sensitivity to lovastatin treatment compared to DOC-resistant A549 (A549/D16) cells, indicating a potential application of statins/chemotherapy combination therapy to control wild-type and abnormal TP53-containing human lung tumors. Full article
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<p>Determination of the DOC and lovastatin sensitivities in lung cancer cells by MTT assay. To evaluate the sensitivity of DOC and lovastatin in lung cancer cells with different TP53 statuses, varied concentrations of DOC (<b>a</b>) (2.5 to 40 nM) and (<b>d</b>) lovastatin (2.5 to 40 μM) were applied on A549, H460, H1299, H1355, CL1-0, and CL1-5 cells. (<b>b</b>) The half-maximal inhibitory concentration (IC50) of each cell line to DOC and (<b>e</b>) lovastatin were determined accordingly. IC50 for each cell line to (<b>c</b>) Either DOC or (<b>f</b>) lovastatin sensitivity were determined and statistically analyzed with the TP53 status, respectively. * A value of <span class="html-italic">p</span> &lt; 0.05 was considered to be statistically significant.</p>
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<p>Inhibition of wt-TP53 protein by PFTα followed by DOC or lovastatin to measure drug sensitivity of lung cancer cells. (<b>a</b>) H460 cells were pretreated with DMSO or PFTα (10 μM) for 48 h, then treated either with DOC (20 nM) or lovastatin (10 μM) for another 48 h. Similar treatments were applied to (<b>c</b>) A549 cells, and the images of the cells were taken with 100× magnification using a light microscope. The viability of (<b>b</b>) H460 cells and (<b>d</b>) A549 cells were calculated, followed by an MTT assay. * Statistically significant.</p>
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<p>Lovastatin sensitivities of DOC-resistant A549 and H1299 sublines. (<b>a</b>) A549 cells were pretreated either with varied concentrations of lovastatin alone for 30 min or in combination with DOC (16 nM) for an additional 48 h. Similar treatments were applied to A549/D16 cells followed by MTT assay (<b>b</b>) H1299 cells and H299/D8 cells were treated either with varied concentrations of lovastatin alone or combined with DOC (8 nM) for 48 h followed by MTT assay.</p>
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<p>A simplified conclusion has been obtained and summarized.</p>
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19 pages, 5414 KiB  
Article
Application of Graph Models to the Identification of Transcriptomic Oncometabolic Pathways in Human Hepatocellular Carcinoma
by Sergio Barace, Eva Santamaría, Stefany Infante, Sara Arcelus, Jesus De La Fuente, Enrique Goñi, Ibon Tamayo, Idoia Ochoa, Miguel Sogbe, Bruno Sangro, Mikel Hernaez, Matias A. Avila and Josepmaria Argemi
Biomolecules 2024, 14(6), 653; https://doi.org/10.3390/biom14060653 - 3 Jun 2024
Cited by 1 | Viewed by 1328
Abstract
Whole-tissue transcriptomic analyses have been helpful to characterize molecular subtypes of hepatocellular carcinoma (HCC). Metabolic subtypes of human HCC have been defined, yet whether these different metabolic classes are clinically relevant or derive in actionable cancer vulnerabilities is still an unanswered question. Publicly [...] Read more.
Whole-tissue transcriptomic analyses have been helpful to characterize molecular subtypes of hepatocellular carcinoma (HCC). Metabolic subtypes of human HCC have been defined, yet whether these different metabolic classes are clinically relevant or derive in actionable cancer vulnerabilities is still an unanswered question. Publicly available gene sets or gene signatures have been used to infer functional changes through gene set enrichment methods. However, metabolism-related gene signatures are poorly co-expressed when applied to a biological context. Here, we apply a simple method to infer highly consistent signatures using graph-based statistics. Using the Cancer Genome Atlas Liver Hepatocellular cohort (LIHC), we describe the main metabolic clusters and their relationship with commonly used molecular classes, and with the presence of TP53 or CTNNB1 driver mutations. We find similar results in our validation cohort, the LIRI-JP cohort. We describe how previously described metabolic subtypes could not have therapeutic relevance due to their overall downregulation when compared to non-tumoral liver, and identify N-glycan, mevalonate and sphingolipid biosynthetic pathways as the hallmark of the oncogenic shift of the use of acetyl-coenzyme A in HCC metabolism. Finally, using DepMap data, we demonstrate metabolic vulnerabilities in HCC cell lines. Full article
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<p>Using graphs to adapt public signatures. (<b>A</b>) Violin plot showing the median gene to gene correlation (MGGC) of selected Hallmark signatures in the LIHC HCC cohort, including those related to proliferation (green), metabolism (light blue), and unrelated to liver or liver cancer (dark blue). (<b>B</b>) MGGC of signatures from the Metabolic Atlas (MetAtlas). (<b>C</b>) Scheme of the method of adaptation of public signatures from the Molecular Signature Database (MSigDB) and MetAtlas to identify centric nodes and metabolic clusters using graphs. (<b>D</b>) Effect of the method on the MGGC of metabolic signatures from MSigDB and MetAtlas in LIHC. (<b>E</b>) An example of a non-filtered co-expression matrix of “Xenobiotic Metabolism” signature of the MetAtlas in the LIHC cohort, where all genes (nodes) are connected in an apparently equal relationship (edge). (<b>F</b>) An example of a Louvain cluster obtained by after graph-based adaptation was applied to the “Xenobiotic Metabolism” signature.</p>
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<p>Identification of metabolic clusters in HCC and their association with transcriptomic classes. (<b>A</b>) LIHC was used as the training cohort, where tumor (HCC, <span class="html-italic">n</span> = 359) and non-tumor (NT, <span class="html-italic">n</span> = 49) samples were analyzed. (<b>B</b>) From the original MSigDB and MetAtlas signatures, unrestricted co-expression matrix (r threshold 0.05) led to the identification of only 148 metabolic clusters in HCC and 183 in NT, which increased to 261 and 454 in HCC and NT, respectively, with an r threshold of 0.4, as used in downstream analyses. These clusters included 1182 and 1785 unique genes, 369 and 445 core genes, and 143 and 273 central genes in HCC and NT, respectively (see <a href="#sec2-biomolecules-14-00653" class="html-sec">Section 2</a>). (<b>C</b>–<b>F</b>) Overlap between signatures (<b>C</b>), unique genes (<b>D</b>), unique core genes (<b>E</b>), and unique central genes (<b>F</b>) found in HCC and NT. (<b>G</b>) Heatmap of ssGSEA scores using newly identified metabolic clusters and their association with Hoshida classes S1, S2, and S3. (<b>H</b>–<b>J</b>) Ridge plots showing the expression of signatures belonging to group 1, 2, and 3 by Hoshida class S1, S2 and S3.</p>
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<p>Validation of the method for prognostic prediction in patients with HCC. (<b>A</b>) A random 50:50 split of the LIHC cohort led to the training (<span class="html-italic">n</span> = 180) and validation (<span class="html-italic">n</span> = 179) cohorts for prognostic analyses, while the LIRI-JP cohort (<span class="html-italic">n</span> = 200) was used as the test cohort. (<b>B</b>,<b>C</b>) Overall ssGSEA scores of prognostic signatures ABAT, DMGDH and GLYAT when comparing tumor vs. non-tumor in LIHC (<b>C</b>) and LIRI-JP (<b>D</b>). (<b>E</b>,<b>F</b>) Survival analyses of patients in LIHC-training, LIHC-validation and LIRI-JP-testing cohorts when dividing the population into high and low ssGSEA scores for ABAT (<b>E</b>), DMGDH (<b>F</b>) and GLYAT signatures.</p>
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<p>IDI1, GMPPA, and SPTLC1-centered clusters are overexpressed metabolic signatures in HCC. (<b>A</b>) Ridge plots of ssGSEA scores of Isopentenyl-diphosphate delta-isomerase 1 (IDI1) signature in LIHC and LIRI-JP cohorts compared with paired non-tumor tissue. (<b>B</b>,<b>C</b>) Box plots showing the expression levels of individual genes included in the IDI1 signature in LIHC (<b>B</b>) and LIRI-JP (<b>C</b>) cohorts. (<b>D</b>) Ridge plots of ssGSEA scores of GDP-mannose pyrophosphorylase A (GMPPA) signature in LIHC and LIRI-JP cohorts compared with paired non-tumor tissue. (<b>E</b>,<b>F</b>) Box plots showing the expression levels of individual genes included in GMPPA signature in LIHC (<b>E</b>) and LIRI-JP (<b>F</b>) cohorts. (<b>G</b>) Ridge plots of ssGSEA scores of Serine Palmitoyltransferase Long-Chain Base Subunit 1 (SPTLC1) signature in the LIHC and LIRI-JP cohorts compared with paired non-tumor tissue. (<b>H</b>,<b>I</b>) Box plots showing the expression levels of individual genes included in GMPPA signature in the LIHC (<b>H</b>) and LIRI-JP (<b>I</b>) cohorts. Abbreviations: * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Identification of metabolic vulnerabilities in HCC cell lines using DepMap. (<b>A</b>) Gene dependency scores for individual genes included in the IDI1 signature. (<b>B</b>) Gene effect scores for individual genes included in the IDI1 signature. (<b>C</b>) Gene dependency scores for individual genes included in the GMPPA signature. (<b>D</b>) Gene effect scores for individual genes included in the GMPPA signature. (<b>E</b>) Gene dependency scores for individual genes included in the SPTLC1 signature. (<b>F</b>) Gene effect scores for individual genes included in the SPTLC1 signature.</p>
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<p>Theoretical model depicting the N-glycan, mevalonate, and sphingolipid biosynthetic pathways as integrated oncometabolic responses lead to a shift in Acetyl CoA use in HCC.</p>
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11 pages, 1472 KiB  
Article
Investigating Novel IspE Inhibitors of the MEP Pathway in Mycobacterium
by Seoung-Ryoung Choi and Prabagaran Narayanasamy
Microorganisms 2024, 12(1), 18; https://doi.org/10.3390/microorganisms12010018 - 21 Dec 2023
Cited by 1 | Viewed by 1451
Abstract
In a recent effort to mitigate harm from human pathogens, many biosynthetic pathways have been extensively evaluated for their ability to inhibit pathogen growth and to determine drug targets. One of the important products/targets of such pathways is isopentenyl diphosphate. Isopentenyl diphosphate is [...] Read more.
In a recent effort to mitigate harm from human pathogens, many biosynthetic pathways have been extensively evaluated for their ability to inhibit pathogen growth and to determine drug targets. One of the important products/targets of such pathways is isopentenyl diphosphate. Isopentenyl diphosphate is the universal precursor of isoprenoids, which are essential for the normal functioning of microorganisms. In general, two biosynthetic pathways lead to the formation of isopentenyl diphosphate: (1) the mevalonate pathway in animals; and (2) the non-mevalonate or methylerythritol phosphate (MEP) in many bacteria, and some protozoa and plants. Because the MEP pathway is not found in mammalian cells, it is considered an attractive target for the development of antimicrobials against a variety of human pathogens, including Mycobacterium tuberculosis (M.tb). In the MEP pathway, 4-diphosphocytidyl-2-c-methyl-d-erythritol kinase (IspE) phosphorylates 4-diphosphocytidyl-2-C-methyl-D-erythritol (CDPME) to form 4-diphosphocytidyl-2-C-methyl-D-erythritol 2-phosphate (CDPME2P). A virtual high-throughput screening against 15 million compounds was carried out by docking IspE protein. We identified an active heterotricyclic compound which showed enzymatic activity; namely, IC50 of 6 µg/mL against M.tb IspE and a MIC of 12 µg/mL against M.tb (H37Rv). Hence, we designed and synthesized similar new heterotricyclic compounds and tested them against mycobacterium, observing a MIC of 5 µg/mL against M. avium. This study will provide the critical insight necessary for developing novel antimicrobials that target the MEP pathways in pathogens. Full article
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Graphical abstract

Graphical abstract
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<p>MEP pathway: Enzyme IspC made MEP, IspD synthesized CDPME and IspE phosphory ated to CDPME2P.</p>
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<p>Lead IspE inhibitor, A1.</p>
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<p>Autodocking of A1 with M.tb IspE. The docking was predicted using SwissDock [<a href="#B21-microorganisms-12-00018" class="html-bibr">21</a>,<a href="#B22-microorganisms-12-00018" class="html-bibr">22</a>] IspE (PDB: 3PYG).</p>
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<p>Scheme for IspE targeted drug discovery: Hit molecules were obtained from an in silico docking study with IspE protein and 15 million commercially available compounds. Virtual screening with experimental determination of inhibitory activity led to the discovery of compound <b>A1</b> as a lead structure against mycobacteria, including <span class="html-italic">M. avium</span>, <span class="html-italic">M. abscessus</span>, and <span class="html-italic">M. tuberculosis</span>.</p>
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<p>Synthesis of carboline derivatives designed from A1 compound.</p>
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25 pages, 6674 KiB  
Article
Concurrent Activation of Both Survival-Promoting and Death-Inducing Signaling by Chloroquine in Glioblastoma Stem Cells: Implications for Potential Risks and Benefits of Using Chloroquine as Radiosensitizer
by Andreas Müller, Patrick Weyerhäuser, Nancy Berte, Fitriasari Jonin, Bogdan Lyubarskyy, Bettina Sprang, Sven Rainer Kantelhardt, Gabriela Salinas, Lennart Opitz, Walter Schulz-Schaeffer, Alf Giese and Ella L. Kim
Cells 2023, 12(9), 1290; https://doi.org/10.3390/cells12091290 - 30 Apr 2023
Cited by 3 | Viewed by 2313
Abstract
Lysosomotropic agent chloroquine was shown to sensitize non-stem glioblastoma cells to radiation in vitro with p53-dependent apoptosis implicated as one of the underlying mechanisms. The in vivo outcomes of chloroquine or its effects on glioblastoma stem cells have not been previously addressed. This [...] Read more.
Lysosomotropic agent chloroquine was shown to sensitize non-stem glioblastoma cells to radiation in vitro with p53-dependent apoptosis implicated as one of the underlying mechanisms. The in vivo outcomes of chloroquine or its effects on glioblastoma stem cells have not been previously addressed. This study undertakes a combinatorial approach encompassing in vitro, in vivo and in silico investigations to address the relationship between chloroquine-mediated radiosensitization and p53 status in glioblastoma stem cells. Our findings reveal that chloroquine elicits antagonistic impacts on signaling pathways involved in the regulation of cell fate via both transcription-dependent and transcription-independent mechanisms. Evidence is provided that transcriptional impacts of chloroquine are primarily determined by p53 with chloroquine-mediated activation of pro-survival mevalonate and p21-DREAM pathways being the dominant response in the background of wild type p53. Non-transcriptional effects of chloroquine are conserved and converge on key cell fate regulators ATM, HIPK2 and AKT in glioblastoma stem cells irrespective of their p53 status. Our findings indicate that pro-survival responses elicited by chloroquine predominate in the context of wild type p53 and are diminished in cells with transcriptionally impaired p53. We conclude that p53 is an important determinant of the balance between pro-survival and pro-death impacts of chloroquine and propose that p53 functional status should be taken into consideration when evaluating the efficacy of glioblastoma radiosensitization by chloroquine. Full article
(This article belongs to the Special Issue Cell Death Mechanisms and Therapeutic Opportunities in Glioblastoma)
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<p>Effects of ClQ on GSCs proliferation in vitro. GSCs were treated with ClQ (30 µM), irradiation (IR, 2.5 Gy) or combination of ClQ+IR for 72 h and analyzed by immunofluorescence staining for Ki-67. Summary of the data from three independent experiments. Statistical significance was determined using Student’s <span class="html-italic">t</span>-test. (*), <span class="html-italic">p</span> ≤ 0.05; (**); <span class="html-italic">p</span> ≤ 0.01; (***), <span class="html-italic">p</span> ≤ 0.001. “ns”, not significant.</p>
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<p>Effects of ClQ on GSCs viability in vitro. GSCs were treated with ClQ (30 µM), irradiation (IR, 2.5 Gy) or combination of ClQ+IR for 72 h and assessed for the sub-G1 content by flow cytometry. Summary of the data obtained from three independent experiments. Statistical significance was determined by an unpaired <span class="html-italic">t</span>-test with Welch’s correction. (*), <span class="html-italic">p</span> ≤ 0.05; (***), <span class="html-italic">p</span> ≤ 0.001; (****), <span class="html-italic">p</span> ≤ 0.0001, “ns”, not significant.</p>
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<p>Effects of ClQ in vivo. Survival analyses of GSC xenografted mice treated with ClQ (<b>a</b>), radiation (<b>b</b>) or combination of ClQ and IR (<b>c</b>). Solid lines correspond to sham-treated control groups. Kaplan–Meier curves of mice survival were determined using the log-rank test.</p>
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<p>Effects of ClQ in vivo. Survival analyses of GSC xenografted mice treated with ClQ (<b>a</b>), radiation (<b>b</b>) or combination of ClQ and IR (<b>c</b>). Solid lines correspond to sham-treated control groups. Kaplan–Meier curves of mice survival were determined using the log-rank test.</p>
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<p>Effects of ClQ on p53, p53-Ser46P and p21 proteins. Top, representative blots for wtp53 or R273H-p53 expressing GSCs treated with ClQ for 24 h and 48 h. Protein loading was ascertained by probing for the mitochondrial resident mtHSP70. Graph shows quantitative evaluations of p53 and p21 levels by densitometry, in untreated or ClQ-treated GSCs. For total protein normalization, mitochondrial HSP70 or b-actin were used as internal loading controls. Data from three independent experiments were analyzed for each line.</p>
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<p>Effects of ClQ on p53, p53-Ser46P and p21 proteins. Top, representative blots for wtp53 or R273H-p53 expressing GSCs treated with ClQ for 24 h and 48 h. Protein loading was ascertained by probing for the mitochondrial resident mtHSP70. Graph shows quantitative evaluations of p53 and p21 levels by densitometry, in untreated or ClQ-treated GSCs. For total protein normalization, mitochondrial HSP70 or b-actin were used as internal loading controls. Data from three independent experiments were analyzed for each line.</p>
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<p>Assessment of p53 and MDM2-Ser395P proteins in wtp53 expressing GSCs. Representative blot for wtp53 GSCs treated with ClQ for 24 h and 48 h. Experiments were performed at least three times.</p>
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<p>Dual effect of ClQ on ATM phosphorylation at Ser1981 and structural integrity of the ATM-Ser1981P protein. Top panel shows representative blots for ATM-Ser1981P in wtp53 (#993), R273H-p53 (G112) or p53-null GSCs after 72 h of treatment with ClQ. Graph shows the results of quantitative evaluations of the full-length and truncated ATM-Ser1891P levels by densitometry (n = 3 for each line). For total protein normalization, mitochondrial HSP70 or b-actin were used as internal loading controls.</p>
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<p>Assessments of HIPK2 proteins in GSCs differing for the p53 status. Western blot data for total and Tyr361P phosphorylated HIPK2 in GSCs expressing wtp53 (#993), R273H-p53 (G112) or p53-null GSCs after 72 h of treatment with ClQ. Top panel shows representative blots for total HIPK2 and HIPK2-Tyr361P isoform in wtp53 (#993), R273H-p53 (G112) or p53-null GSCs after 72 h of treatment with ClQ. Graph shows the results of quantitative evaluations by densitometry (n = 3 for each line). For total protein normalization, mitochondrial HSP70 or b-actin were used as internal loading controls.</p>
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<p>Schematic presentation of ClQ_DEGs identified in GSCs differing for the p53 status. “p53RGs”, p53-regulated genes. “up”, upregulated ClQ_DEGs. “down”, down-regulated ClQ_DEGs. Encircled numbers correspond to known p53RGs.</p>
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<p>Effects of ClQ on apoptosis signaling pathways. Readouts from the APOSIG arrays incubated with cell lysates of (<b>a</b>) wtp53 or (<b>b</b>) R273H GSCs either untreated or treated with ClQ for 72 h and graphical presentation of the quantified readouts.</p>
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<p>Effect of ClQ on the abundance of AKT kinase. Top panel shows representative blots for total HIPK2 and HIPK2-Tyr361P isoform in wtp53 (#993), R273H-p53 (G112) or p53-null GSCs after 72 h of treatment with ClQ. Graph shows the results of quantitative evaluations of datasets from independent experiments (n = 3 for each line) by densitometry. For total protein normalization, mitochondrial HSP70 or b-actin were used as internal loading controls.</p>
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<p>Effects of ClQ on the autophagic activity in GSCs differing for p53 status. Western blot assessments of late autophagy markers p63 and LC3B-II in untreated or ClQ-treated (72 h) GSCs. Protein loading was ascertained by probing for β-actin.</p>
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<p>Schematic summary of main results integrated into the known networks of survival or death pathways. Green lines indicate molecular impacts of ClQ identified in this study. Solid and dashed indicate, respectively, sustained or diminished signaling in the context of wtp53 or transcriptionally impaired p53.</p>
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56 pages, 12047 KiB  
Review
Over 40 Years of Fosmidomycin Drug Research: A Comprehensive Review and Future Opportunities
by Talea Knak, Mona A. Abdullaziz, Stefan Höfmann, Leandro A. Alves Avelar, Saskia Klein, Matthew Martin, Markus Fischer, Nobutada Tanaka and Thomas Kurz
Pharmaceuticals 2022, 15(12), 1553; https://doi.org/10.3390/ph15121553 - 14 Dec 2022
Cited by 18 | Viewed by 4945
Abstract
To address the continued rise of multi-drug-resistant microorganisms, the development of novel drugs with new modes of action is urgently required. While humans biosynthesize the essential isoprenoid precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) via the established mevalonate pathway, pathogenic protozoa and [...] Read more.
To address the continued rise of multi-drug-resistant microorganisms, the development of novel drugs with new modes of action is urgently required. While humans biosynthesize the essential isoprenoid precursors isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) via the established mevalonate pathway, pathogenic protozoa and certain pathogenic eubacteria use the less well-known methylerythritol phosphate pathway for this purpose. Important pathogens using the MEP pathway are, for example, Plasmodium falciparum, Mycobacterium tuberculosis, Pseudomonas aeruginosa and Escherichia coli. The enzymes of that pathway are targets for antiinfective drugs that are exempt from target-related toxicity. 2C-Methyl-D-erythritol 4-phosphate (MEP), the second enzyme of the non-mevalonate pathway, has been established as the molecular target of fosmidomycin, an antibiotic that has so far failed to be approved as an anti-infective drug. This review describes the development and anti-infective properties of a wide range of fosmidomycin derivatives synthesized over the last four decades. Here we discuss the DXR inhibitor pharmacophore, which comprises a metal-binding group, a phosphate or phosphonate moiety and a connecting linker. Furthermore, non-fosmidomycin-based DXRi, bisubstrate inhibitors and several prodrug concepts are described. A comprehensive structure–activity relationship (SAR) of nearly all inhibitor types is presented and some novel opportunities for further drug development of DXR inhibitors are discussed. Full article
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Figure 1

Figure 1
<p>Structural formula of the natural product fosmidomycin (<b>1</b>) and its acetyl analog FR900098 (<b>2</b>).</p>
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<p>Additional phosphono-hydroxamic acids published by the Fujisawa Pharmaceutical Co., Ltd. [<a href="#B21-pharmaceuticals-15-01553" class="html-bibr">21</a>].</p>
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<p>Passage of DXR inhibitors across seven membranes in <span class="html-italic">Plasmodium</span>-infected erythrocytes. Adapted with permission from <span class="html-italic">J. Med. Chem</span>. 2015, 58, 4, 2025–2035 [<a href="#B37-pharmaceuticals-15-01553" class="html-bibr">37</a>]. Copyright 2022 American Chemical Society.</p>
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<p>The MEP pathway leading to the isoprenoid precursors isopentenyl diphosphate (<b>XVII, IPP</b>) and dimethylallyl diphosphate (<b>XIX, DMAPP</b>) via an IspC/DXR-catalysed conversion of 1-deoxy-D-xylulose 5-phosphate (<b>XII, DXP</b>) to 2-C-methyl-D-erythritol 4-phosphate (<b>XIII, MEP</b>).</p>
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<p>Two conceivable mechanisms for the enzymatic mode of action of DXR involving a divalent metal cation M<sup>2+</sup> (grey sphere) and NADPH [<a href="#B87-pharmaceuticals-15-01553" class="html-bibr">87</a>]. Used with permission of EUREKA SCIENCE, from Targeting the MethylErythritol Phosphate(MEP) Pathway for Novel Antimalarial, Antibacterial and Herbicidal Drug Discovery: Inhibition of 1-Deoxy-D-Xylulose-5-Phosphate Reductoisomerase (DXR) Enzyme, Nidhi Singh, Volume 13, Issue 11, 2007; permission conveyed through Copyright Clearance Center, Inc.</p>
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<p>(<b>A</b>): Amino acid sequence alignment of bacterial and parasitic DXRs. Residues involved in phosphate/phosphonate-, linker-, and metal and hydroxamate-binding are highlighted in blue, green, and red, respectively. The colored ribbons above the sequence alignment represent the respective domains in <span class="html-italic">Pf</span>DXR: the NADPH-binding (blue), catalytic (green), and C-terminal (red) domains. The linker region and flexible loop in the catalytic domain are colored yellow and orange, respectively. The pink bars and cyan arrows represent the secondary structure elements, namely, α-helices and β-strands, respectively; (<b>B</b>): The overall structure of the quaternary (enzyme-NADPH-metal-inhibitor) complex of <span class="html-italic">Pf</span>DXR (PDB 3AU9) [<a href="#B91-pharmaceuticals-15-01553" class="html-bibr">91</a>]. Three domains, a linker region, and a flexible loop in the catalytic domain of one subunit are colored as in (<b>A</b>). The other subunit is colored grey. The bound fosmidomycin (FOS) and NADPH molecules are shown as ball-and-stick (cyan) and stick (grey) models, respectively. The bound magnesium ions are shown as sphere models (pink).</p>
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<p>The binding mode of fosmidomycin in the active site of <span class="html-italic">Pf</span>DXR. Residues involved in the inhibitor binding are colored as in <a href="#pharmaceuticals-15-01553-f006" class="html-fig">Figure 6</a>A. The number in the parentheses indicates the residue number for the equivalent residue of <span class="html-italic">Ec</span>DXR.</p>
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<p>(<b>A</b>) Binding of <b>1</b> and natural substrate DXP (<b>III</b>) to a metal ion, represented by a grey sphere. (<b>B</b>) Simplified pharmacophore model of fosmidomycin-based DXR inhibitors MGB: Metal-binding group.</p>
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<p>Structures, antibacterial, and antiplasmodial activities of the reverse fosmidomycin analogs <b>3</b>–<b>6</b>.</p>
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<p>Structures and biological activities of compounds <b>7</b><span class="html-italic">–</span><b>9</b> with modified MBGs.</p>
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<p>Structures and biological activities of analogs <b>10</b><span class="html-italic">–</span><b>29</b> with alternative chelating functionalities.</p>
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<p>Biological activities of the potential bisubstrate inhibitors <b>30</b><span class="html-italic">–</span><b>37</b>. Values marked with * indicate the percentage of inhibition at 100 μM.</p>
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<p>Biological activities of analogs <b>38</b><span class="html-italic">–</span><b>41.</b> Values marked with * indicate the percentage of inhibition at 100 μM.</p>
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<p>Biological activity of the fosmidomycin and FR900098 derivatives (<b>42</b>–<b>46</b>) with an <span class="html-italic">α,β</span>-unsaturated linker. <b>*</b> Ammonium salts were prepared. <sup>a</sup> Values in parentheses are the percent remaining enzyme activity at 100 μM.</p>
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<p>Structure and biological activity of the oxa analogs <b>47</b><span class="html-italic">–</span><b>54</b>.</p>
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<p>Biological activity of conformationally restricted analogs <b>55</b><span class="html-italic">–</span><b>60</b>.</p>
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<p>Antibacterial and antiplasmodial activities of α-phenyl derivatives (<b>61</b><span class="html-italic">–</span><b>76</b>). <sup>a</sup> Diethanolammonium salt was prepared. <sup>b</sup> Ammonium salts were prepared.</p>
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<p>Structure–activity relationship of α-substituted FR900098 analogs <b>77</b>–<b>90</b>, the <span class="html-italic">N</span>-formyl analog <b>91</b> and their activity against <span class="html-italic">Mt</span>DXR.</p>
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<p>Compound <b>89</b> (turquoise carbon atoms) docked in the X-ray structure of <span class="html-italic">Mt</span>DXR in complex with 3 orange carbon atoms (PDB code 2Y1G) [<a href="#B128-pharmaceuticals-15-01553" class="html-bibr">128</a>]. The Gly198-Met208 flap (colored in pink) from the 2JVC structure representing <span class="html-italic">Mt</span>DXR bound to fosmidomycin (<b>1</b>). Reprinted with permission from <span class="html-italic">J. Org. Chem. 2011, 76, 21, 8986–8998</span> [<a href="#B129-pharmaceuticals-15-01553" class="html-bibr">129</a>]. Copyright 2022 American Chemical Society.</p>
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<p>Biological activities of α-halogenated phosphonic acid derivatives (<b>92</b><span class="html-italic">–</span><b>96</b>). * Ammonium salts were prepared.</p>
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<p>Biological data of structurally diverse <span class="html-italic">α</span>-substituted analogs <b>97</b>–<b>104</b>.</p>
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<p>Rational design of α-pyridinyl DXR-inhibitors <b>105a, b</b> and <b>106a, b</b>. K<sub>i</sub> values are given in µM (black) or nM (blue) against <span class="html-italic">Ec</span>DXR, <span class="html-italic">Pf</span>DXR and <span class="html-italic">Pf</span>Dd2.</p>
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<p>(<b>A</b>) overall structure of <span class="html-italic">Pf</span>DXR in complex with Mn<sup>2+</sup> (brown sphere), <b>106b</b> (green) and NADPH. (<b>B</b>) Close-up view of the active site of <span class="html-italic">Pf</span>DXR:<b>106b</b>. Reproduced from Xue et al. (PDB: 4GAE [<a href="#B139-pharmaceuticals-15-01553" class="html-bibr">139</a>].</p>
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<p>Biological data of <span class="html-italic">α</span>-substituted reverse fosmidomycin analogs (<b>105</b>–<b>109</b>).</p>
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<p>Schematic overview between <b>110b</b> (green) and the active site of <span class="html-italic">Ec</span>DXR. Intramolecular van der Waals interactions (light blue) between the <span class="html-italic">N</span>-methyl group with the difluorophenyl ring and the linker atoms of <b>110b</b>. Distances are in Å [<a href="#B100-pharmaceuticals-15-01553" class="html-bibr">100</a>]. Reprinted with permission from <span class="html-italic">J. Med. Chem.</span> 2011, 54, 6796–6802 [<a href="#B100-pharmaceuticals-15-01553" class="html-bibr">100</a>]. Copyright 2022 American Chemical Society.</p>
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<p>Antibacterial and antiplasmodial activity of thia (<b>112+113</b>), oxa (<b>114+115</b>), sulfone (<b>116</b>) and aza (<b>117</b>) analogs.</p>
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<p>Antiplasmodial activity of β- and γ-substituted analogs (<b>118</b><span class="html-italic">–</span><b>121</b>).</p>
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<p>Biological data of phosphonic acid isosteres. Light blue: hydroxamate moiety. Grey: hydroxamic acid moiety. a: R = H. b: R = methyl. n.d. = not determined. Fosmidomycin (<b>1</b>) as a reference compound.</p>
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<p>Structure–activity relationship (SAR) of fosmidomycin derivatives. EW = electron withdrawing, ED = electron donating, o = ortho, MBG = metal binding group.</p>
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<p>Lipophilic phosphonate prodrugs used for fosmidomycin and its analogs.</p>
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<p>Results of in vivo studies of lipophilic FR900098 (<b>2</b>) esters. <span style="color:#00B0F0">Blue</span> indicates improvement and <span style="color:gray">grey</span> reduction of efficacy/plasma concentration of the prodrug compared to parent compound <b>2</b>. p.o. = per os, p.i. = postinfection.</p>
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<p>Antiplasmodial and antimycobacterial activity of acyloxybenzyl (<b>157</b>) and alkoxyalkyl phosphonate ester prodrugs (<b>158</b>).</p>
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<p>Inhibitory activity of different FR900098 prodrugs (<b>169</b>–<b>177</b>) against <span class="html-italic">M. tuberculosis</span> H37Rv in growth assay.</p>
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<p>Antimycobacterial activity of prodrugs (<b>178</b><span class="html-italic">–</span><b>180</b>) against M. smegmatis determined by paper disc diffusion method.</p>
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<p>Structure and antiplasmodial activity of prodrugs <b>181</b> and <b>182</b>.</p>
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<p>Antiplasmodial activity of α-benzyl and α-alkyl analogs <b>183</b><span class="html-italic">–</span><b>198</b>. Derivatives were screened for their inhibition of <span class="html-italic">P. falciparum</span> 3D7 growth at 0.5, 1 and 25 µM.</p>
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<p>Antiplasmodial activity of parent compounds (<b>110a</b>, <b>110b</b>, <b>114b</b>) and prodrugs (<b>199</b><span class="html-italic">–</span><b>205</b>) against <span class="html-italic">Pf</span>3D7.</p>
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<p>Inhibitory activity of rigidized prodrugs <b>206</b><span class="html-italic">–</span><b>208</b> against <span class="html-italic">Pf</span>Dd2 or <span class="html-italic">Mt</span> H37Ra.</p>
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<p>Schematic overview of reverse α-3,4-difluorophenyl-substituted β-oxa and carba analogs.</p>
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<p>Antiplasmodial activity of double prodrugs <b>209</b><span class="html-italic">–</span><b>219</b> against asexual blood stages of <span class="html-italic">Pf</span>-K1 (IC<sub>50</sub> in μM) and <span class="html-italic">Mt</span> H37Rv (MIC in μM).</p>
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<p>Biological data of amino acid-based prodrugs <b>220a</b>–<b>f</b>, <b>221a</b>–<b>f</b>, <b>222a</b>–<b>b</b>, and <b>223a</b>–<b>f</b> against asexual blood stages of <span class="html-italic">Pf</span>-K1 (IC<sub>50</sub> in μM) and <span class="html-italic">Mt</span> H37Rv (MIC in μM). AAS = Amino acid side chain.</p>
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<p>Structures of aryl phosphoramidate prodrugs of fosmidomycin (<b>224</b>) and FR900098 (<b>225</b>).</p>
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<p>Structure and antiplasmodial activity of fosmidomycin (<b>226</b>) and FR900098 (<b>227</b>) octaarginine conjugates.</p>
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<p>Antiplasmodial activities of artemisinin (ART)-conjugates <b>228</b>–<b>229</b> and desalkylchloroquin (DCQ) hybrids (<b>230</b>–<b>231</b>) against chloroquine-resistant <span class="html-italic">P. falciparum</span> FcB1 strain with ART and CQ as references.</p>
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<p>Structure and biological data of non-fosmidomycin-based DXR inhibitors <b>232</b>–<b>240</b>.</p>
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<p>Superposition of fosmidomycin (green) PDB 1ONP, compound <b>235</b> (blue) PDB 3ANM and compound <b>232</b> (pink) PDB 1T1R in the structure of <span class="html-italic">Ec</span>DXR (salmon) PDB 1ONP.</p>
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<p>Structures of natural products (<b>241</b>–<b>246</b>) that potentially act as DXR inhibitors. Lead structures for the design of DXRi identified via HTS by Haymond et al. [<a href="#B195-pharmaceuticals-15-01553" class="html-bibr">195</a>].</p>
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<p>(<b>i</b>) 1. Na, EtOH, 70 °C, 1.5 h, 2. 1,3-dibromopropane, 2 h, rt to reflux, (<b>ii</b>) 1. NaH, benzene, dibutyl phosphonate, reflux, 3.5 h, 2. <b>VII</b>, reflux, 5.6 h (<b>iii</b>) 6 N HCl, acetic acid, 20 h, reflux (<b>iva</b>) 1. formic acid, acetic anhydride, 1.1 h, 0 to 5 °C, 2. NH<sub>3</sub> (28 % aq. sol.), (<b>ivb</b>) acetic anhydride, water, rt, 1.5 h, Ts = tosyl, PMB = p-methoxybenzyl.</p>
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11 pages, 1295 KiB  
Article
Antitumor Activity of Simvastatin in Preclinical Models of Mantle Cell Lymphoma
by Juliana Carvalho Santos, Núria Profitós-Pelejà, Marcelo Lima Ribeiro and Gaël Roué
Cancers 2022, 14(22), 5601; https://doi.org/10.3390/cancers14225601 - 15 Nov 2022
Cited by 6 | Viewed by 2610
Abstract
Background: Mantle cell lymphoma (MCL) is a rare and aggressive subtype of B-cell non-Hodgkin lymphoma that remains incurable with standard therapy. Statins are well-tolerated, inexpensive, and widely prescribed as cholesterol-lowering agents to treat hyperlipidemia and to prevent cardiovascular diseases through the blockage of [...] Read more.
Background: Mantle cell lymphoma (MCL) is a rare and aggressive subtype of B-cell non-Hodgkin lymphoma that remains incurable with standard therapy. Statins are well-tolerated, inexpensive, and widely prescribed as cholesterol-lowering agents to treat hyperlipidemia and to prevent cardiovascular diseases through the blockage of the mevalonate metabolic pathway. These drugs have also shown promising anti-cancer activity through pleiotropic effects including the induction of lymphoma cell death. However, their potential use as anti-MCL agents has not been evaluated so far. Aim: The present study aimed to investigate the activity of simvastatin on MCL cells. Methods: We evaluated the cytotoxicity of simvastatin in MCL cell lines by CellTiter-Glo and lactate dehydrogenase (LDH) release assays. Cell proliferation and mitotic index were assessed by direct cell recounting and histone H3-pSer10 immunostaining. Apoptosis induction and reactive oxygen species (ROS) generation were evaluated by flow cytometry. Cell migration and invasion properties were determined by transwell assay. The antitumoral effect of simvastatin in vivo was evaluated in a chick embryo chorioallantoic membrane (CAM) MCL xenograft model. Results: We show that treatment with simvastatin induced a 2 to 6-fold LDH release, inhibited more than 50% of cell proliferation, and enhanced the caspase-independent ROS-mediated death of MCL cells. The effective impairment of MCL cell survival was accompanied by the inhibition of AKT and mTOR phosphorylation. Moreover, simvastatin strongly decreased MCL cell migration and invasion ability, leading to a 55% tumor growth inhibition and a consistent diminution of bone marrow and spleen metastasis in vivo. Conclusion: Altogether, these data provide the first preclinical insight into the effect of simvastatin against MCL cells, suggesting that this agent might be considered for repurpose as a precise MCL therapy. Full article
(This article belongs to the Special Issue Women’s Special Issue Series: Oncology)
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<p>MCL cytotoxicity, proliferation impairment and cell death induced by simvastatin. (<b>A</b>) Cell viability of MCL cell lines in the presence or absence of different doses of simvastatin; (<b>B</b>) cytotoxicity rates assessed by LDH release of MCL cell lines in presence or absence of 5 μM, 10 μM and 20 μM simvastatin; (<b>C</b>) Western blot evaluation of phospho-AKT and phospho-mTOR levels after the treatment with 5 μM, 10 μM and 20 μM simvastatin, or vehicle. Full western blot images can be seen in <a href="#app1-cancers-14-05601" class="html-app">Figure S4</a>. (<b>D</b>) Proliferation rate assessed by MCL cell counting after the treatment with increasing doses of simvastatin; (<b>E</b>) proliferation rate assessed by phospho-Histone 3 (red) immunofluorescence of MCL cell lines in the presence or absence of 5 μM, 10 μM or 20 μM simvastatin. Nuclei were counterstained with DAPI (blue); (<b>F</b>) mitochondrial transmembrane potential (ΔΨm) after cell treatment with 5 μM, 10 μM or 20 μM simvastatin or vehicle; (<b>G</b>) apoptosis rate measured by AnnexinV-FITC/PI staining after cell treatment with 5 μM, 10 μM or 20 μM simvastatin or vehicle, previously treated or not with 10 μM of the pan-caspase inhibitor, Q-VD-OPh hydrate; (<b>H</b>) ROS generation measured by DHE (dihydroethidium) staining in MCL cells lines treated with 5 μM, 10 μM or 20 μM simvastatin, or vehicle. Values are expressed as mean ± SEM. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, when compared to control group.</p>
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<p>MCL migration and invasion ability, tumor growth and metastasis inhibited by simvastatin treatment. (<b>A</b>) Cell migration index of MCL cell lines exposed to 10 μM of simvastatin or vehicle for 24 h; (<b>B</b>) cell invasion index of MCL cell lines exposed to 10 μM simvastatin or vehicle for 24 h; (<b>C</b>) scheme depicting the chick embryo chorioallantoic membrane (CAM) model; (<b>D</b>) representative pictures of engrafted MCL tumors treated with 10 μM simvastatin or vehicle on day 16 of embryonic development. The dotted line delimitates the tumor; (<b>E</b>) tumor weight on day 16 of embryonic development after the treatment with 10 μM simvastatin or vehicle; (<b>F</b>) H&amp;E and immunohistochemical (IHC) detection of CD20 and H3-pSer10 in tissue sections from CAM-tumor specimens dosed with 10 μM simvastatin or vehicle; (<b>G</b>) metastasis evaluation measured by qPCR-based Alu-sequence presence into embryo’s bone marrow and spleen. Values are expressed as mean ± SEM. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, when compared to the control group.</p>
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17 pages, 6283 KiB  
Article
Phenotypical and Functional Alteration of γδ T Lymphocytes in COVID-19 Patients: Reversal by Statins
by Marta Di Simone, Anna Maria Corsale, Elena Lo Presti, Nicola Scichilone, Carmela Picone, Lydia Giannitrapani, Francesco Dieli and Serena Meraviglia
Cells 2022, 11(21), 3449; https://doi.org/10.3390/cells11213449 - 31 Oct 2022
Cited by 1 | Viewed by 2108
Abstract
(1) Background: statins have been considered an attractive class of drugs in the pharmacological setting of COVID-19 due to their pleiotropic properties and their use correlates with decreased mortality in hospitalized COVID-19 patients. Furthermore, it is well known that statins, which block the [...] Read more.
(1) Background: statins have been considered an attractive class of drugs in the pharmacological setting of COVID-19 due to their pleiotropic properties and their use correlates with decreased mortality in hospitalized COVID-19 patients. Furthermore, it is well known that statins, which block the mevalonate pathway, affect γδ T lymphocyte activation. As γδ T cells participate in the inflammatory process of COVID-19, we have investigated the therapeutical potential of statins as a tool to inhibit γδ T cell pro-inflammatory activities; (2) Methods: we harvested peripheral blood mononuclear cells (PBMCs) from COVID-19 patients with mild clinical manifestations, COVID-19 recovered patients, and healthy controls. We performed ex vivo flow cytometry analysis to study γδ T cell frequency, phenotype, and exhaustion status. PBMCs were treated with Atorvastatin followed by non-specific and specific stimulation, to evaluate the expression of pro-inflammatory cytokines; (3) Results: COVID-19 patients had a lower frequency of circulating Vδ2+ T lymphocytes but showed a pronounced pro-inflammatory profile, which was inhibited by in vitro treatment with statins; (4) Conclusions: the in vitro capacity of statins to inhibit Vδ2+ T lymphocytes in COVID-19 patients highlights a new potential biological function of these drugs and supports their therapeutical use in these patients. Full article
(This article belongs to the Collection Cellular Immunology and COVID-19)
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<p>Frequency of Vδ1+ and Vδ2+ T lymphocytes in hospitalized and recovered COVID-19 patients and in healthy subjects. (<b>A</b>) Distribution of percentages of total lymphocytes, T (CD3+), Vδ1+ and Vδ2+ T lymphocytes in hospitalized and recovered COVID-19 patients, compared to healthy subjects. Shown is mean ± SD. (<b>B</b>) Representative dot-plots showing the frequency of Vδ1+ and Vδ2+ T lymphocytes in hospitalized and recovered COVID-19 patients and healthy subjects. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Phenotypic analysis of circulating Vδ1+ and Vδ2+ T lymphocytes in hospitalized and recovered COVID-19 patients and in healthy subjects. Distribution of ex vivo memory subsets of Vδ1+ (<b>A</b>) and Vδ2+ (<b>C</b>) T lymphocytes based on the expression of CD27 and CD45RA in hospitalized and recovered COVID-19 patients, compared to healthy donors. Median is shown. Healthy donors were represented as triangle, COVID-19 patients as circle and COVID-19 recovered as rhombus. Representative dot-plots showing Vδ1+ (<b>B</b>) and Vδ2+ (<b>D</b>) T lymphocyte memory subset distribution in hospitalized, recovered, and healthy subjects. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Analysis of exhaustion-marker expression by circulating Vδ1+ and Vδ2+ T lymphocytes in hospitalized and recovered COVID-19 patients and healthy subjects. Expression of TIM-3 and PD-1 on Vδ1+ (<b>A</b>) and Vδ2+ (<b>B</b>) T lymphocytes in hospitalized and recovered COVID-19 patients, compared to healthy donors. Shown are percentage (<b>left panels</b>) and MFI (<b>right panels</b>) ± SD. (<b>C</b>) Representative dot-plots of exhaustion-marker expression by Vδ1+ and Vδ2+ T lymphocytes from hospitalized and recovered COVID-19 patients, compared to healthy donors. (<b>D</b>) Frequency of exhausted Vδ1+ and Vδ2+ T cells per 1 × 10<sup>6</sup> T lymphocytes. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, and **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Expression of pro-inflammatory cytokines by Vδ1+ T lymphocytes in hospitalized and recovered COVID-19 patients, compared to healthy subjects. Cumulative histograms representing the expression of pro-inflammatory cytokines by Vδ1+ T lymphocyte. Shown are percentage (<b>left panels</b>), MFI (<b>central panel</b>, log<sub>10</sub> scale), and iMFI (<b>right panels</b>) ± SD. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, and **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Expression of pro-inflammatory cytokines by Vδ2+ T lymphocytes in hospitalized and recovered COVID-19 patients, compared to healthy subjects. Cumulative histograms representing the expression of pro-inflammatory cytokines. Shown are percentage (<b>left panels</b>), MFI (<b>central panel</b>, log<sub>10</sub> scale), and iMFI (<b>right panels</b>) ± SD. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span> &lt; 0.001, and **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Intracellular cytokine expression by Vδ2+ T lymphocytes in COVID-19 patients and healthy donors upon zoledronate stimulation. Intracellular levels of IFN-γ, TNF-α, and IL-17, in terms of percentage and iMFI, expressed by Vδ2+ T cells, are represented as histogram plots. Shown is mean ± SD. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span>&lt; 0.001, and **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Inhibition of Vδ2+ T cell cytokine expression by atorvastatin upon zoledronate stimulation (<b>A</b>) Intracellular levels of TNF-α, IFN-γ, and IL-17 expressed by Vδ2+ T cells from COVID-19 patients upon stimulation with zoledronate in presence of atorvastatin. Data are represented as histogram plots. Each histogram shows mean ± SD. Purple histogram represented Zoledronate condition, lilac histogram represented Zoledronate + 10 μM statin condition, and pink histogram represented Zoledronate + 50 μM statin condition. (<b>B</b>) Representative counterplots showing pro-inflammatory cytokine expression by Vδ2+ T lymphocytes. * <span class="html-italic">p</span> &lt; 0.05, ** <span class="html-italic">p</span> &lt; 0.01, *** <span class="html-italic">p</span>&lt; 0.001, and **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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<p>Inhibition of Vδ2+ T cell cytokine expression by atorvastatin upon Iono/PMA stimulation. (<b>A</b>) Intracellular levels of TNF-α, IFN-γ, and IL-17 expressed by Vδ2+ T cells from COVID-19 patients upon stimulation with Iono/PMA in presence of atorvastatin. Data are represented as histogram plots, showing mean ± SD. Blue histogram represented Iono/PMA condition, light blue histogram represented Iono/PMA + 10 μM statin condition, and light blue powder histogram represented Iono/PMA + 50 mM statin condition. (<b>B</b>) Representative counterplots showing pro-inflammatory cytokine expression by Vδ2+ T lymphocytes. * <span class="html-italic">p</span> &lt; 0.05, *** <span class="html-italic">p</span>&lt; 0.001, and **** <span class="html-italic">p</span> &lt; 0.0001.</p>
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32 pages, 2471 KiB  
Review
Phytoecdysteroids: Distribution, Structural Diversity, Biosynthesis, Activity, and Crosstalk with Phytohormones
by Yamshi Arif, Priyanka Singh, Andrzej Bajguz and Shamsul Hayat
Int. J. Mol. Sci. 2022, 23(15), 8664; https://doi.org/10.3390/ijms23158664 - 4 Aug 2022
Cited by 15 | Viewed by 4048
Abstract
Phytoecdysteroids (PEs) are naturally occurring polyhydroxylated compounds with a structure similar to that of insect molting hormone and the plant hormone brassinosteroids. PEs have a four-ringed skeleton composed of 27, 28, 29, or 30 carbon atoms (derived from plant sterols). The carbon skeleton [...] Read more.
Phytoecdysteroids (PEs) are naturally occurring polyhydroxylated compounds with a structure similar to that of insect molting hormone and the plant hormone brassinosteroids. PEs have a four-ringed skeleton composed of 27, 28, 29, or 30 carbon atoms (derived from plant sterols). The carbon skeleton of ecdysteroid is known as cyclopentanoperhydrophenanthrene and has a β-sidechain on C-17. Plants produce PEs via the mevalonate pathway with the help of the precursor acetyl-CoA. PEs are found in algae, fungi, ferns, gymnosperms, and angiosperms; more than 500 different PEs are found in over 100 terrestrial plants. 20-hydroxyecdysone is the most common PE. PEs exhibit versatile biological roles in plants, invertebrates, and mammals. These compounds contribute to mitigating biotic and abiotic stresses. In plants, PEs play a potent role in enhancing tolerance against insects and nematodes via their allelochemical activity, which increases plant biological and metabolic responses. PEs promote enzymatic and non-enzymatic antioxidant defense systems, which decrease reactive oxygen species in the form of superoxide radicals and hydroxyl radicals and reduce malondialdehyde content. PEs also induce protein biosynthesis and modulate carbohydrate and lipid synthesis. In humans, PEs display biological, pharmacological, and medicinal properties, such as anti-diabetic, antioxidant, anti-microbial, hepatoprotective, hypoglycemic, anti-cancer, anti-inflammatory, antidepressant, and tissue differentiation activity. Full article
(This article belongs to the Special Issue Hormones and Animal-Derived Compounds of Plants)
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<p>Structures of widely distributed phytoecdysteroids.</p>
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<p>Structural modifications of ccdysteroids via etherification, esterification, oxidation, amination, fluorination, and alkylation.</p>
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<p>Structural modifications of ccdysteroids via etherification, esterification, oxidation, amination, fluorination, and alkylation.</p>
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<p>Biosynthesis of phytoecdysteroids.</p>
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<p>Pictorial representation of distribution, isolation, biosynthesis, and biological roles of phytoecdysteroids.</p>
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<p>Phytoecdysteroid’s mechanistic approach to enhancing plant stress tolerance.</p>
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25 pages, 3143 KiB  
Review
The Reductive Dehydroxylation Catalyzed by IspH, a Source of Inspiration for the Development of Novel Anti-Infectives
by Hannah Jobelius, Gabriella Ines Bianchino, Franck Borel, Philippe Chaignon and Myriam Seemann
Molecules 2022, 27(3), 708; https://doi.org/10.3390/molecules27030708 - 21 Jan 2022
Cited by 10 | Viewed by 3794
Abstract
The non-mevalonate or also called MEP pathway is an essential route for the biosynthesis of isoprenoid precursors in most bacteria and in microorganisms belonging to the Apicomplexa phylum, such as the parasite responsible for malaria. The absence of this pathway in mammalians makes [...] Read more.
The non-mevalonate or also called MEP pathway is an essential route for the biosynthesis of isoprenoid precursors in most bacteria and in microorganisms belonging to the Apicomplexa phylum, such as the parasite responsible for malaria. The absence of this pathway in mammalians makes it an interesting target for the discovery of novel anti-infectives. As last enzyme of this pathway, IspH is an oxygen sensitive [4Fe-4S] metalloenzyme that catalyzes 2H+/2e- reductions and a water elimination by involving non-conventional bioinorganic and bioorganometallic intermediates. After a detailed description of the discovery of the [4Fe-4S] cluster of IspH, this review focuses on the IspH mechanism discussing the results that have been obtained in the last decades using an approach combining chemistry, enzymology, crystallography, spectroscopies, and docking calculations. Considering the interesting druggability of this enzyme, a section about the inhibitors of IspH discovered up to now is reported as well. The presented results constitute a useful and rational help to inaugurate the design and development of new potential chemotherapeutics against pathogenic organisms. Full article
(This article belongs to the Special Issue Biomimetic Radical Chemistry and Applications 2021)
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<p>Some examples of isoprenoids and their biological precursors. The common five-carbon precursors are highlighted in red.</p>
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<p>Structures of IspH deposited in the PDB database with their corresponding ligand.</p>
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<p>Crystallographic structures depicting the rotation of the hydroxymethyl group [<a href="#B45-molecules-27-00708" class="html-bibr">45</a>]. (<b>a</b>) The IspH WT was incubated with the substrate HMBPP. The full iron-sulfur cluster is present and the CH<sub>2</sub>OH group is coordinated to the apical iron, stabilized by T167. (<b>b</b>) The IspH T167C mutant was incubated with the substrate HMBPP. The CH<sub>2</sub>OH group has rotated about almost 180° and is now stabilized by the diphosphate group as well as the glutamate E126. The crystal structure only shows a [3Fe-4S] cluster.</p>
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<p>Schematic representation of the HiPIP-like η<sup>3</sup>-allyl (π/σ) complex. The hyperfine coupling constants <span class="html-italic">A<sub>iso</sub></span> obtained after HYSCORE measurements of <sup>13</sup>C-labelled HMBPP as well as the iron-carbon distances <span class="html-italic">d</span><sub>Fe-C</sub> estimated by DFT calculations are given for the C2, C3, and C4 atom [<a href="#B68-molecules-27-00708" class="html-bibr">68</a>].</p>
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<p>Substrate analogs as inhibitors of IspH.</p>
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<p>In silico docking result of the IspH inhibitor candidate <b>30</b> designed based on the structure of <span class="html-italic">E. coli</span> IspH:<b>26</b> (PDB ID: 3ZGN) and showing the best docking score. (<b>a</b>) Docking result of <b>30</b> binding to IspH; (<b>b</b>) active site; (<b>c</b>) chemical structure of <b>30</b>.</p>
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<p>Compounds <b>31</b>–<b>44</b>, tested as inhibitors of IspH from <span class="html-italic">A. aeolicus</span>.</p>
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<p>Structural representation of <span class="html-italic">Ec</span>-IspH in complex with compound <b>38</b> (PDB code 4MUX) [<a href="#B50-molecules-27-00708" class="html-bibr">50</a>]. The amino acids are shown as sticks, as well as the [4Fe-4S] cluster and the ligands.</p>
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<p>Compounds <b>45</b>–<b>51</b>, tested as inhibitors of IspH from <span class="html-italic">A. aeolicus</span>.</p>
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<p>Compounds <b>52</b>– <b>55</b> as inhibitors of IspH. The origin of IspH for inhibitions assays of <b>54</b> and <b>55</b> was not mentioned by the authors.</p>
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<p>Methylerythritol phosphate pathway. The reaction catalyzed by IspH is framed.</p>
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<p>Proposition for the mechanism of the IspH catalyzed reductive dehydroxylation.</p>
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<p>Substrate analogs of HMBPP used for the study of C-O bond cleavage [<a href="#B63-molecules-27-00708" class="html-bibr">63</a>,<a href="#B64-molecules-27-00708" class="html-bibr">64</a>]. Discrepancies from the natural substrate HMBPP are highlighted in yellow.</p>
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<p>(<b>a</b>) Stereochemical course of deuterium and hydrogen after incubation with IspH in D<sub>2</sub>O and isopentenyl diphosphate isomerase in H<sub>2</sub>O [<a href="#B75-molecules-27-00708" class="html-bibr">75</a>]. (<b>b</b>) Substrate analog <b>25</b> used by Liu et al. and the product formed in the IspH catalyzed reaction [<a href="#B76-molecules-27-00708" class="html-bibr">76</a>].</p>
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<p>Reactions of the inhibitors <b>49</b> and <b>50</b> catalyzed by the enzyme IspH in the oxidized state. The ligand bound to the apical iron could also be an OH.</p>
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20 pages, 4394 KiB  
Article
Aryl Hydrocarbon Receptor (AhR) Activation by 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD) Dose-Dependently Shifts the Gut Microbiome Consistent with the Progression of Non-Alcoholic Fatty Liver Disease
by Russell R. Fling and Timothy R. Zacharewski
Int. J. Mol. Sci. 2021, 22(22), 12431; https://doi.org/10.3390/ijms222212431 - 18 Nov 2021
Cited by 7 | Viewed by 3785
Abstract
Gut dysbiosis with disrupted enterohepatic bile acid metabolism is commonly associated with non-alcoholic fatty liver disease (NAFLD) and recapitulated in a NAFLD-phenotype elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mice. TCDD induces hepatic fat accumulation and increases levels of secondary bile acids, including [...] Read more.
Gut dysbiosis with disrupted enterohepatic bile acid metabolism is commonly associated with non-alcoholic fatty liver disease (NAFLD) and recapitulated in a NAFLD-phenotype elicited by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in mice. TCDD induces hepatic fat accumulation and increases levels of secondary bile acids, including taurolithocholic acid and deoxycholic acid (microbial modified bile acids involved in host bile acid regulation signaling pathways). To investigate the effects of TCDD on the gut microbiota, the cecum contents of male C57BL/6 mice orally gavaged with sesame oil vehicle or 0.3, 3, or 30 µg/kg TCDD were examined using shotgun metagenomic sequencing. Taxonomic analysis identified dose-dependent increases in Lactobacillus species (i.e., Lactobacillus reuteri). Increased species were also associated with dose-dependent increases in bile salt hydrolase sequences, responsible for deconjugation reactions in secondary bile acid metabolism. Increased L. reuteri levels were further associated with mevalonate-dependent isopentenyl diphosphate (IPP) biosynthesis and o-succinylbenzoate synthase, a menaquinone biosynthesis associated gene. Analysis of the gut microbiomes from cirrhosis patients identified an increased abundance of genes from the mevalonate-dependent IPP biosynthesis as well as several other menaquinone biosynthesis genes, including o-succinylbenzoate synthase. These results extend the association of lactobacilli with the AhR/intestinal axis in NAFLD progression and highlight the similarities between TCDD-elicited phenotypes in mice to human NAFLD. Full article
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<p>TCDD enriched Lactobacillus species in the cecum microbiota. Taxa abundance were assessed in metagenomic cecum samples from male C57BL/6 mice following oral gavage with sesame oil vehicle or 0.3, 3, or 30 µg/kg TCDD every 4 days for 28 days (<span class="html-italic">n</span> = 3). Significant shifts in relative abundances of taxa are presented at the (<b>A</b>) phylum, (<b>B</b>) genus, (<b>C</b>) and species levels. Significance is denoted with an asterisk (*; adjusted <span class="html-italic">p</span>-value &lt; 0.1).</p>
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<p>TCDD enriched Lactobacillus species possessing bile salt hydrolase (<span class="html-italic">bsh</span>). The presence of <span class="html-italic">bsh</span> gene sequences were assessed in metagenomic caecum samples from male C57BL/6 mice following oral gavage with sesame oil vehicle or 0.3, 3, or 30 µg/kg TCDD every 4 days for 28 days using three independent cohorts (<span class="html-italic">n</span> = 3). (<b>A</b>) The presence (green boxes) or absence of <span class="html-italic">bsh</span> sequences detected in any of the metagenomic samples (<span class="html-italic">n</span> = 3) are denoted within the respective treatment groups. Significant increases (*) or decreases (@) in normalized <span class="html-italic">bsh</span> abundances (adj. <span class="html-italic">p</span> &lt; 0.1) are denoted. Also denoted is significantly increased species (#) determined by taxonomic analysis that corresponded with respective RefSeq species <span class="html-italic">bsh</span> annotations. Significance was determined by Maaslin2 R package. (<b>B</b>) Volcano plot displaying log2(fold-changes) in relative abundance of species between vehicle and 30 µg/kg TCDD treatment groups versus -log(adjusted <span class="html-italic">p</span>-values [adj. <span class="html-italic">p</span>]). Red dots denotes <span class="html-italic">bsh</span> sequences detected in 30 µg/kg TCDD treatment group. Significance was determined by the DeSeq2 R package comparing only vehicle and 30 µg/kg TCDD groups. Red dashed lines are reference to −log(0.05) value for the <span class="html-italic">y</span>-axis and −1 and 1 for the <span class="html-italic">x</span>-axis.</p>
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<p>TCDD enriched genes from the mevalonate-dependent isoprenoid biosynthesis pathway. Relative abundance of genes involved in isoprenoid biosynthesis and grouped by enzyme commission (EC) numbers for the mevalonate dependent and 2-C-methyl-D-erythritol 4-phosphate (MEP) pathways in cecum samples from male C57BL6 mice following oral gavage with sesame oil vehicle or 0.3, 3, or 30 µg/kg TCDD every 4 days for 28 days (<span class="html-italic">n</span> = 3). Individual box plots are also numbered with the EC number matching the enzymatic step in pathway schematic. Adjusted <span class="html-italic">p</span>-values (adj. <span class="html-italic">p</span>) were determined by the Maaslin2 R package. Abbreviations: 3-hydroxyl-3-methyl-clutaryl-CoA (HMG-CoA), (R)-5-Phosphomevalonate (mevalonate-5P), (R)-5-Diphosphomevalonate (mevalonate-5PP), 2-C-Methyl-D-erythritol 4-phosphate (MEP), 4-(Cytidine 5′-diphospho)-2-C-methyl-D-erythritol (CDP-ME), 4-(Cytidine 5′-diphospho)-2-C-methyl-D-erythritol (DEP-ME-2P), 2-C-Methyl-D-erythritol 2,4-cyclodiphosphate (MEcPP), and 1-Hydroxy-2-methyl-2-butenyl 4-diphosphate (HMBPP).</p>
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<p>Mevalonate-dependent isoprenoid biosynthesis genes are enriched in a published metagenomics dataset of fecal samples from cirrhosis patients. Humann3 analysis of fecal gut microbiomes in healthy (H, red, <span class="html-italic">n</span> = 52), compensated (C, green, <span class="html-italic">n</span> = 48), or decompensated (D, blue, <span class="html-italic">n</span> = 44) cirrhosis for mevalonate-dependent and methyl-D-erythritol 4-phosphate (MEP) pathways. Individual boxplots are numbered with the EC number matching the enzymatic step in pathway schematic. Significance is denoted with a red asterisk (*, adjusted <span class="html-italic">p</span>-values &lt; 0.05) compared to healthy group. Abbreviations.: 3-hydroxyl-3-methyl-clutaryl-CoA (HMG-CoA), (R)-5-Phosphomevalonate (mevalonate-5P), (R)-5-Diphosphomevalonate (mevalonate-5PP), 2-C-Methyl-D-erythritol 4-phosphate (MEP), 4-(Cytidine 5′-diphospho)-2-C-methyl-D-erythritol (CDP-ME), 4-(Cytidine 5′-diphospho)-2-C-methyl-D-erythritol (DEP-ME-2P), 2-C-Methyl-D-erythritol 2,4-cyclodiphosphate (MEcPP), 1-Hydroxy-2-methyl-2-butenyl 4-diphosphate (HMBPP).</p>
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<p>Relative abundance of polyprenol transferase EC annotations identified in the mouse cecum metagenomic dataset. Stacked bar plots represent mean relative abundance of grouped EC numbers (<span class="html-italic">n</span> = 3) and represent identified species that contributed to mean total abundance for each treatment group. The number of isopentenyl diphosphate (IPP) and farnesyl diphosphate (FPP) molecules used for respective polyprenol biosynthesis are also denoted. Adjusted <span class="html-italic">p</span>-values were determined by the Maaslin2 R package. Abbreviations: isopentenyl diphosphate (IPP), geranyl diphosphate (GPP), polyprenyl diphosphate (polyprenyl-PP).</p>
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<p>Peptidoglycan biosynthesis was unchanged by TCDD. (<b>A</b>) Relative abundance of peptidoglycan biosynthesis EC numbers identified in the metagenomic dataset. (<b>B</b>) Relative abundance of only Lactobacillus species classified to peptidoglycan biosynthesis EC numbers. Individual boxplots are numbered with the EC number matching the enzymatic step in pathway schematic. Adjusted <span class="html-italic">p</span>-values (adj. <span class="html-italic">p</span>) were determined by MAASLIN2. Abbreviations: UDP-N-acetyl-alpha-D-glucosamine (UDP-GlcNac), UDP-N-acetylmuramate (UDP-MurNAc), UDP-N-acetyl-alpha-D-muramoyl-L-alanine (UDP-MurNAc-ALA), UDP-N-acetyl-alpha-D-muramoyl-L-alanyl-D-glutamate(UDP-MurNAc-Ala-D-Glu), UDP-N-acetylmuramoyl-L-alanyl-gamma-D-glutamyl-meso-2,6-diaminopimelate (UDP-MurNAc-Ala-D-Glu-m-DAP), D-Alanyl-D-alanine (D-Ala-D-Ala), UDP-N-acetylmuramoyl-L-alanyl-D-glutamyl-6-carboxy-L-lysyl-D-alanyl-D-alanine (UDP-MurNAc-Ala-D-Glu-m-DAP-D-Ala-D-Ala), Undecaprenyl-diphospho-N-acetylmuramoyl-L-alanyl-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine (Und-PP-MurNAc-Ala-D-Glu-m-DAP-D-Ala-D-Ala),Undecaprenyl-diphospho-N-acetylmuramoyl-(N-acetylglucosamine)-L-alanyl-D-glutamyl-meso-2,6-diaminopimeloyl-D-alanyl-D-alanine (Und-PP-MurNAc-GlcNAc-Ala-D-Glu-m-DAP-D-Ala-D-Ala).</p>
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<p>TCDD-elicited effects on menaquinone biosynthesis. (<b>A</b>) Relative abundance of menaquinone biosynthesis EC annotations identified in the metagenomic dataset. Individual stacked bar plots are labeled with the EC number matching the enzymatic step in pathway schematic. Stacked bar plots of annotated EC numbers involved in menaquinone biosynthesis. Values are mean relative abundance (<span class="html-italic">n</span> = 3) classified to the respective species and in cecum samples from male C57BL/6 mice following oral gavage with sesame oil vehicle or 0.3, 3, or 30 µg/kg TCDD every 4 days for 28 days. (<b>B</b>) Menaquinone biosynthesis EC numbers classified to Lactobacillus species in the cecum metagenomic datasets. Adjusted <span class="html-italic">p</span>-values (adj. <span class="html-italic">p</span>) were determined by Maaslin2 R package.</p>
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<p>Menaquinone biosynthesis genes are increased in cirrhotic patients. Humann3 analysis of fecal metagenomic dataset of patients with healthy (H, red, <span class="html-italic">n</span> = 52), compensated (C, green, <span class="html-italic">n</span> = 48), or decompensated (D, blue, <span class="html-italic">n</span> = 44) liver cirrhosis diagnosis for EC numbers in menaquinone biosynthesis. Individual box plots are labeled with the EC number matching the enzymatic step in pathway schematic. Significance is denoted with a red asterisk (*; adjusted <span class="html-italic">p</span>-values &lt; 0.05) with the healthy group as reference.</p>
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18 pages, 3506 KiB  
Article
Inhibition of Orbivirus Replication by Fluvastatin and Identification of the Key Elements of the Mevalonate Pathway Involved
by Fauziah Mohd Jaafar, Baptiste Monsion, Mourad Belhouchet, Peter P. C. Mertens and Houssam Attoui
Viruses 2021, 13(8), 1437; https://doi.org/10.3390/v13081437 - 23 Jul 2021
Cited by 7 | Viewed by 2859
Abstract
Statin derivatives can inhibit the replication of a range of viruses, including hepatitis C virus (HCV, Hepacivirus), dengue virus (Flavivirus), African swine fever virus (Asfarviridae) and poliovirus (Picornaviridae). We assess the antiviral effect of fluvastatin in [...] Read more.
Statin derivatives can inhibit the replication of a range of viruses, including hepatitis C virus (HCV, Hepacivirus), dengue virus (Flavivirus), African swine fever virus (Asfarviridae) and poliovirus (Picornaviridae). We assess the antiviral effect of fluvastatin in cells infected with orbiviruses (bluetongue virus (BTV) and Great Island virus (GIV)). The synthesis of orbivirus outer-capsid protein VP2 (detected by confocal immunofluorescence imaging) was used to assess levels of virus replication, showing a reduction in fluvastatin-treated cells. A reduction in virus titres of ~1.7 log (98%) in fluvastatin-treated cells was detected by a plaque assay. We have previously identified a fourth non-structural protein (NS4) of BTV and GIV, showing that it interacts with lipid droplets in infected cells. Fluvastatin, which inhibits 3-hydroxy 3-methyl glutaryl CoA reductase in the mevalonic acid pathway, disrupts these NS4 interactions. These findings highlight the role of the lipid pathways in orbivirus replication and suggest a greater role for the membrane-enveloped orbivirus particles than previously recognised. Chemical intermediates of the mevalonic acid pathway were used to assess their potential to rescue orbivirus replication. Pre-treatment of IFNAR(−/−) mice with fluvastatin promoted their survival upon challenge with live BTV, although only limited protection was observed. Full article
(This article belongs to the Special Issue Bluetongue Virus: Pathogenesis and Vaccines)
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Figure 1
<p>A neighbour-joining phylogenetic tree constructed using MEGA X, showing the clustering of <span class="html-italic">Culicoides sonorensis</span> 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase amongst insect HMG-CoA reductase enzymes. Accession numbers of sequences used to construct the tree are provided in <a href="#app1-viruses-13-01437" class="html-app">Supplemental Table S1</a>.</p>
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<p>Effect of fluvastatin on cell viability. (<b>A</b>) Effect of increasing concentrations of fluvastatin on BSR cell viability. Cells were harvested at 72 h post-treatment and assessed by an MTT viability assay. (<b>B</b>) Effect of increasing concentrations of fluvastatin on KC cell viability. Cells were harvested on day 5 post-treatment.</p>
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<p>The mevalonate pathway of mammals. Key steps inhibited by statins (inhibition of HMG-CoA reductase), zaragozic acid A (inhibition of squalene synthase), geranyl-geranyl pyrophosphate or farnesyl pyrophosphate inhibitors are indicated.</p>
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<p>YFV17D-infected BSR cells treated with fluvastatin, inhibitors of geranyl-geranylation (geranyl-geranyl transferase inhibitor GGTI-2133 or farnesyl pyrophosphate transferase inhibitor FTPIII), inhibitors of squalene synthase (zaragozic acid), or treated with fluvastatin then supplemented with components of the mevalonate pathway (mevalonic acid, geranyl-geranyl pyrophosphate, farnesyl pyrophosphate or cholesterol) in attempts to restore virus replication in fluvastatin-treated cells. These results are representative of four distinct experiments. Error bars with standard deviations are shown.</p>
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<p>Confocal fluorescence microscopy of Great Island virus (GIV) or BTV infected BSR cells treated with fluvastatin. GIV infected cells were labelled with anti-GIV-NS4 (non-structural protein) and Alexa Fluor 488 (green fluorescence) conjugated anti-rabbit IgG. BTV infected cells were labelled with anti-BTV-NS4 and Alexa Fluor 488 (green fluorescence) conjugated anti-rabbit IgG or anti-BTV-8 VP2 and Alexa Fluor 568 (red fluorescence) conjugated anti-mouse IgG. Nuclei were stained with DAPI (blue). (<b>A</b>) Non-treated GIV infected cell control showing the NS4 spherical bodies. (<b>B</b>) GIV infected cells treated with fluvastatin, showing an almost complete disappearance of the NS4 spherical bodies and low levels of NS4 expression in the cells. (<b>C</b>) Non-treated BTV-8 infected-cell control showing NS4 in the cytoplasm and nucleus. (<b>D</b>) BTV infected cells treated with fluvastatin, showing an almost complete disappearance of the NS4 signal. (<b>E</b>) Non-treated BTV-8 infected-cell control showing strong expression of VP2 across the cells. (<b>F</b>) BTV-8 infected cells treated with fluvastatin, showing a significant drop of the VP2 signal.</p>
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<p>Effects of fluvastatin, mevalonate pathway-components and inhibitors on BTV replication in BSR cells. BTV-8 titres (PFU/mL) generated in BTV-8-infected BSR cells, treated with: fluvastatin; inhibitors of geranyl-geranylation (geranyl-geranyl transferase inhibitor GGTI-2133, or farnesyl pyrophosphate transferase inhibitor FTPIII); or inhibitors of squalene synthase (zaragozic acid A). Some cells were treated with fluvastatin then supplemented with components of the mevalonate pathway (mevalonic acid, geranylgeranyl pyrophosphate, farnesyl pyrophosphate or cholesterol), to inhibit, or in attempts to restore, virus replication in fluvastatin-treated cells. These results are representative of 4 independent experiments. Error bars with standard deviations are shown.</p>
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<p>Effects of fluvastatin, mevalonate pathway inhibitors and components on BTV replication in KC cells. BTV-8 virus titres (PFU/mL) generated by infected KC cells treated with fluvastatin, inhibitors of geranylgeranylation (geranyl-geranyl transferase inhibitor GGTI-2133 and farnesyl pyrophosphate transferase inhibitor FTPIII), or inhibitors of squalene synthase (zaragozic acid A). Some cells were treated with fluvastatin then supplemented with mevalonic acid in attempts restore virus replication. These results are representative of three independent experiments. Error bars with standard deviations are shown.</p>
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<p>Survival curves of IFNAR<sup>(−/−)</sup> mice.</p>
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28 pages, 2771 KiB  
Review
Role of Withaferin A and Its Derivatives in the Management of Alzheimer’s Disease: Recent Trends and Future Perspectives
by Rajib Das, Abdur Rauf, Saima Akhter, Mohammad Nazmul Islam, Talha Bin Emran, Saikat Mitra, Ishaq N. Khan and Mohammad S. Mubarak
Molecules 2021, 26(12), 3696; https://doi.org/10.3390/molecules26123696 - 17 Jun 2021
Cited by 34 | Viewed by 5986
Abstract
Globally, Alzheimer’s disease (AD) is one of the most prevalent age-related neurodegenerative disorders associated with cognitive decline and memory deficits due to beta-amyloid deposition (Aβ) and tau protein hyperphosphorylation. To date, approximately 47 million people worldwide have AD. This figure will rise to [...] Read more.
Globally, Alzheimer’s disease (AD) is one of the most prevalent age-related neurodegenerative disorders associated with cognitive decline and memory deficits due to beta-amyloid deposition (Aβ) and tau protein hyperphosphorylation. To date, approximately 47 million people worldwide have AD. This figure will rise to an estimated 75.6 million by 2030 and 135.5 million by 2050. According to the literature, the efficacy of conventional medications for AD is statistically substantial, but clinical relevance is restricted to disease slowing rather than reversal. Withaferin A (WA) is a steroidal lactone glycowithanolides, a secondary metabolite with comprehensive biological effects. Biosynthetically, it is derived from Withania somnifera (Ashwagandha) and Acnistus breviflorus (Gallinero) through the mevalonate and non-mevalonate pathways. Mounting evidence shows that WA possesses inhibitory activities against developing a pathological marker of Alzheimer’s diseases. Several cellular and animal models’ particulates to AD have been conducted to assess the underlying protective effect of WA. In AD, the neuroprotective potential of WA is mediated by reduction of beta-amyloid plaque aggregation, tau protein accumulation, regulation of heat shock proteins, and inhibition of oxidative and inflammatory constituents. Despite the various preclinical studies on WA’s therapeutic potentiality, less is known regarding its definite efficacy in humans for AD. Accordingly, the present study focuses on the biosynthesis of WA, the epidemiology and pathophysiology of AD, and finally the therapeutic potential of WA for the treatment and prevention of AD, highlighting the research and augmentation of new therapeutic approaches. Further clinical trials are necessary for evaluating the safety profile and confirming WA’s neuroprotective potency against AD. Full article
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Figure 1
<p>Biosynthesis of WA. Abbreviations: ACT: acetyltransferase; HMGS: hydroxymethyl glutaryl CoA synthase; HMG-CoA: 3-hydroxy-3-methylglutaryl-co enzyme; HMGR: 3-hydroxy-3-methylglutaryl-coenzyme A reductase; MVAK: mevalonate kinase; IPP: 3-isopentenyl pyrophosphate; GPPS: geranyl pyrophosphate synthase; FPPS: farnesyl diphosphate synthase; SQS: squalene synthase; SQE: squalene epoxidase; CAS: cycloartenol synthase; SMT: sterol methyl transferase; ODM: obtusifoliol-14-demethylase; DOXP: deoxy xylulose pathway; MEP: methyl erythreitol pathway; DXS: 1-deoxy-<span class="html-small-caps">d</span>-xylulose-5-phosphate synthase; DXR: 1-deoxy-<span class="html-small-caps">d</span>-xylulose-5-phosphate reductase; WA: withaferin A.</p>
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<p>Schematic representation showing the target sites of WA action in amyloidogenic pathway that leads to AD. WA inhibits NF-κB signaling (right side). WA regulates several kinase-signaling pathways such as AKT and JAK/STAT. Abbreviations: APP: amyloid precursor protein; Aβ: β-amyloid; TLR: Toll-like receptor; LPS: lipopolysaccharides; IKK: IκB kinase; TNF-α: tumor necrosis factor-α; IL-1β: interleukin-1β; MAP3K7)/TAK1: mitogen-activated protein kinase 7 (MAP3K7)/(TAK1); NF-κB: nuclear factor kappa B; U: ubiquinone; JAK: Janus kinase; STAT: signal transducers and activators of transcription; PTEN: phosphatase and tensin homolog; PDK1: phosphoinositide-dependent kinase-1; AD: Alzheimer disease; WA: withaferin A.</p>
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<p>Overview of inflammatory signaling pathways altered by WA through direct molecular targets. Fibrillary Aβ, oxidative stress, DAMP, and PAMP can contribute to the activation of the inflammasome. Aβ fibrils trigger the activation of microglial cells and thus give signal 1 via NF-κB transcription of pro IL-1β and NLRP3. Intracellular aggregation of soluble Aβ and lysosomal rupture by phagocytosis Aβ fibrils may perform another signal, and oxidative stress contributes to the formation of an active NLRP3 inflammasome. Active caspase-1, released from active NLRP3, converts IL-1β pro to active IL-1β, which is released into extracellular space and leads to neuroinflammation and finally AD. WA prevents NLRP3 inflammasome formation and activation by blocking several steps of this pathway. Abbreviations: ROS: reactive oxygen species; NLEP3: NOD-like receptor protein 3; DAMP: damage-associated molecular pattern; PAMP: pathogen-associated molecular pattern; COX-2: cyclooxygenase-2; IκB: inhibitory subunit of NF-κB; IL-18: interleukin-18; VCAM-1: vascular cell adhesion molecule 1; ICAM-1: intercellular adhesion molecule 1; AD: Alzheimer disease; WA: withaferin A.</p>
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<p>Metabolites of WA: (<b>A</b>) cysteine conjugate of WA; (<b>B</b>) glutathione conjugate of WA. Here, WA: withaferin A.</p>
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22 pages, 3730 KiB  
Article
Synthesis and Antiplasmodial Activity of Novel Fosmidomycin Derivatives and Conjugates with Artemisinin and Aminochloroquinoline
by Despina Palla, Antonia I. Antoniou, Michel Baltas, Christophe Menendez, Philippe Grellier, Elisabeth Mouray and Constantinos M. Athanassopoulos
Molecules 2020, 25(20), 4858; https://doi.org/10.3390/molecules25204858 - 21 Oct 2020
Cited by 11 | Viewed by 4033
Abstract
Malaria, despite many efforts, remains among the most problematic infectious diseases worldwide, mainly due to the development of drug resistance by Plasmodium falciparum. The antibiotic fosmidomycin (FSM) is also known for its antimalarial activity by targeting the non-mevalonate isoprenoid synthesis pathway, which is [...] Read more.
Malaria, despite many efforts, remains among the most problematic infectious diseases worldwide, mainly due to the development of drug resistance by Plasmodium falciparum. The antibiotic fosmidomycin (FSM) is also known for its antimalarial activity by targeting the non-mevalonate isoprenoid synthesis pathway, which is essential for the malaria parasites but is absent in mammalians. In this study, we synthesized and evaluated against the chloroquine-resistant P. falciparum FcB1/Colombia strain, a series of FSM analogs, derivatives, and conjugates with other antimalarial agents, such as artemisinin (ART) and aminochloroquinoline (ACQ). The biological evaluation revealed four new compounds with higher antimalarial activity than FSM: two FSM-ACQ derivatives and two FSM-ART conjugates, with 3.5–5.4 and 41.5–23.1 times more potent activities than FSM, respectively. Full article
(This article belongs to the Special Issue Biological Activities of Natural Products)
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Figure 1
<p>Structures of FSM, FR9000098, and various FSM derivatives.</p>
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<p>Structures of the FSM derivatives synthesized in this work (<b>16</b>–<b>35)</b>.</p>
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<p>Structures of the control drugs (FSM, FR900098, ART, CQ).</p>
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<p>Synthesis of key intermediate <b>39</b>, FSM and FR9000098 monosodium salts, and FSM dimer <b>18</b>; Reagents and conditions: (a) NaH, NaI, DMF, rt to 60 °C, 17 h, 96%; (b) TFA, CH<sub>2</sub>Cl<sub>2</sub>, 0 °C to rt, 1.5 h, 98%; (c) for <b>40</b>: HCOOH, (CH<sub>3</sub>CO)O<sub>2</sub>, −5 °C to rt, overnight, 91% and for <b>41</b>: CH<sub>3</sub>COCl, Et<sub>3</sub>N, DCM, 0 °C to rt, overnight, 98%; (d) H<sub>2</sub>, 10% Pd/C, MeOH, rt (3 h, 91% for <b>16</b> and 4 h, 99% for <b>17</b>); (e) (i) TMSBr, CH<sub>2</sub>Cl<sub>2</sub>, 0 °C to rt, 8 h (ii) 6N aq. NaOH/MeOH (87% for FSM and 90% for FR900098 over 2 steps); (f) succinic anhydride, DIPEA, DMAP, THF, rt, 3 h, 88%; (g) <b>39</b>, HBTU, Et<sub>3</sub>N, CHCl<sub>3</sub>, rt, 3.5 h, 61% (h) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 3 h, 50%.</p>
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<p>Synthesis FSM-ACQ conjugates <b>19</b> and <b>20</b>; Reagents and conditions: (a) <b>44</b>, HBTU, Et<sub>3</sub>N, CHCl<sub>3</sub>, rt, 3.5 h, 61% (b) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 3 h; (c) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 5 h, 97%; (d) <b>44</b>, HBTU, DIPEA, CHCl<sub>3</sub>, rt, 2 h, 60%; (e) Boc<sub>2</sub>O, Et<sub>3</sub>N, DMAP, CH<sub>2</sub>Cl<sub>2</sub>, rt, overnight, 30%; (f) <b>45</b>, HBTU, Et<sub>3</sub>N, CHCl<sub>3</sub>, DMF, 4 h, 50%; (g) TFA, CH<sub>2</sub>Cl<sub>2</sub>, overnight, 60%.</p>
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<p>Synthesis of FSM-ART conjugate <b>21</b>; Reagents and conditions: (a) <b>39</b>, HBTU, Et<sub>3</sub>N, CH<sub>2</sub>Cl<sub>2</sub>, overnight, 50%; (b) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 4 h, 90%.</p>
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<p>Synthesis of the FSM-ART conjugates <b>22</b>–<b>23</b> and FSM derivatives <b>24</b>–<b>25</b>; Reagents and conditions: (a) <b>42</b>, HBTU, DIPEA, CHCl<sub>3</sub>, rt, 7 h (72% for <b>54</b> and 96% for <b>55</b>) (b) TFA, TFE, CH<sub>2</sub>Cl<sub>2</sub>, 5 h (90% for <b>56</b> and 98% for <b>57</b>); (c) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 6.5 h (91% for <b>24</b> and 95% for <b>25</b>); (d) 2× <b>50</b>, HBTU, DIPEA, CH<sub>2</sub>Cl<sub>2</sub>, overnight, 50%; (e) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 4 h (60% for <b>22</b> and 80% for <b>23</b>).</p>
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<p>Synthesis of FSM-amido derivatives <b>26</b>–<b>33</b>; Reagents and conditions: (a) <b>R<sup>1</sup>H</b>, HBTU, DIPEA, CH<sub>2</sub>Cl<sub>2</sub>, rt, 3–6 h, 62%–84%; (b) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 3–5 h, 80%–90%; (c) <b>R<sup>1</sup>H</b>, HBTU, DIPEA, CH<sub>2</sub>Cl<sub>2</sub>, rt, 2 h, 70% for <b>66</b> and 6 h, 84% for <b>68</b>; (d) TFA, TFE, CH<sub>2</sub>Cl<sub>2</sub>, 0 °C to rt, 1 h, 70%; (e) H<sub>2</sub>, 10% Pd/C, MeOH, rt, 2 h, 90% for <b>32</b> and 4 h, 60% for <b>33</b>.</p>
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<p>Synthesis of phosphonate derivatives <b>34</b> and <b>35</b>; Reagents and conditions: (a) DBU, DMF, 1 h, ultrasound, rt, 33%; (b) (i) TMSBr, DCM, 0 °C to rt, 8 h (ii) 6N aq. NaOH/MeOH 75% over 2 steps.</p>
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12 pages, 1294 KiB  
Article
A Gram-Scale Limonene Production Process with Engineered Escherichia coli
by Jascha Rolf, Mattijs K. Julsing, Katrin Rosenthal and Stephan Lütz
Molecules 2020, 25(8), 1881; https://doi.org/10.3390/molecules25081881 - 18 Apr 2020
Cited by 56 | Viewed by 7245
Abstract
Monoterpenes, such as the cyclic terpene limonene, are valuable and important natural products widely used in food, cosmetics, household chemicals, and pharmaceutical applications. The biotechnological production of limonene with microorganisms may complement traditional plant extraction methods. For this purpose, the bioprocess needs to [...] Read more.
Monoterpenes, such as the cyclic terpene limonene, are valuable and important natural products widely used in food, cosmetics, household chemicals, and pharmaceutical applications. The biotechnological production of limonene with microorganisms may complement traditional plant extraction methods. For this purpose, the bioprocess needs to be stable and ought to show high titers and space-time yields. In this study, a limonene production process was developed with metabolically engineered Escherichia coli at the bioreactor scale. Therefore, fed-batch fermentations in minimal medium and in the presence of a non-toxic organic phase were carried out with E. coli BL21 (DE3) pJBEI-6410 harboring the optimized genes for the mevalonate pathway and the limonene synthase from Mentha spicata on a single plasmid. The feasibility of glycerol as the sole carbon source for cell growth and limonene synthesis was examined, and it was applied in an optimized fermentation setup. Titers on a gram-scale of up to 7.3 g·Lorg−1 (corresponding to 3.6 g·L−1 in the aqueous production phase) were achieved with industrially viable space-time yields of 0.15 g·L−1·h−1. These are the highest monoterpene concentrations obtained with a microorganism to date, and these findings provide the basis for the development of an economic and industrially relevant bioprocess. Full article
(This article belongs to the Special Issue Biocatalytic Synthesis of Bioactive Compounds)
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Graphical abstract

Graphical abstract
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<p>The heterologous mevalonate (MVA) pathway and limonene synthase introduced into <span class="html-italic">Escherichia coli</span> for the production of (S)-limonene. Acetoacetyl-CoA synthase from <span class="html-italic">E. coli</span> (atoB), HMG-CoA (hydroxymethylglutaryl-CoA) synthase from <span class="html-italic">Saccharomyces cerevisiae</span> (HMGS), an N-terminal truncated version of HMG-CoA reductase from <span class="html-italic">S. cerevisiae</span> (HMGR), mevalonate kinase (MK), phosphomevalonate kinase (PMK), phosphomevalonate decarboxylase from <span class="html-italic">S. cerevisiae</span> (PMD), isopentenyl diphosphate isomerase from <span class="html-italic">E. coli</span> (idi), a truncated and codon-optimized version of geranyl pyrophosphate synthase from <span class="html-italic">Abies grandis</span> (trGPPS), and a truncated and codon-optimized version of limonene synthase from <span class="html-italic">Mentha spicata</span> without the plastidial targeting sequence (LS).</p>
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<p>Biomass specific yields for different concentrations of the inducer isopropyl β-<span class="html-small-caps">d</span>−1-thiogalactopyranoside (IPTG) after 12 h of cultivation. Two-liquid phase shake flask fermentations with <span class="html-italic">E. coli</span> BL21 (DE3) pJBEI-6410 in M9 minimal medium with 0.5% <span class="html-italic">w</span>/<span class="html-italic">v</span> glucose as the sole carbon source. The error bars relate to biological duplicates.</p>
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<p>Two-liquid phase shake flask fermentations with <span class="html-italic">E. coli</span> BL21 (DE3) pJBEI-6410 in M9 minimal medium with either 0.5% <span class="html-italic">w</span>/<span class="html-italic">v</span> glucose (closed symbols) or glycerol (open symbols) as the sole carbon source. (<b>A</b>) Limonene concentrations (▲, △) in the organic phase and carbon source (<span style="color:#A6A6A6">■</span>, <span style="color:#A6A6A6">□</span>) concentrations were determined at regular intervals. (<b>B</b>) Carbon specific limonene yields after 26 h of cultivation. The error bars relate to biological duplicates.</p>
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<p>Two-liquid phase fed-batch fermentation with <span class="html-italic">E. coli</span> BL21 (DE3) pJBEI-6410 in M9 minimal medium. Cell dry weight (CDW) (■), limonene concentrations (▲) in the organic phase, glycerol (<span style="color:#A6A6A6">▲</span>), acetate (<span style="color:#A6A6A6">▼</span>), and ammonium (<span style="color:#A6A6A6">■</span>) concentrations were determined at regular intervals. The specific activities (<span style="color:#A6A6A6">●</span>) were calculated for distinct time points throughout the fermentation time. The feed rate is displayed as well (dotted line). (<b>A)</b> and (<b>B)</b> display the initial fed-batch fermentation (D = 0.18 h<sup>−1</sup>), whereas (<b>C</b>) and (<b>D</b>) display the optimized fed-batch fermentation with a lower feed rate (D = 0.15 h<sup>−1</sup>) and additional trace element supply. The <span style="color:#221F1F">error bars for CDW relate to two independent measurements.</span></p>
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<p>Two-liquid phase shake flask fermentations with <span class="html-italic">E. coli</span> BL21 (DE3) pJBEI-6410 in M9 minimal medium with either 0.5% <span class="html-italic">w</span>/<span class="html-italic">v</span> glucose (closed symbols, ●) or glycerol (open symbols, ○) as the sole carbon source. Cell dry weights were determined at regular intervals. The error bars relate to biological duplicates.</p>
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