These studies show that gene expression changes in most patients by 2 to 3 hours after ischemic s... more These studies show that gene expression changes in most patients by 2 to 3 hours after ischemic stroke, and in all patients studied by 24 hours. (Stroke. 2007;38[part 2]:691-693.)
Stem cells are found throughout the adult mammalian brain, including the subventricular zone (SVZ... more Stem cells are found throughout the adult mammalian brain, including the subventricular zone (SVZ) adja-cent to the lateral ventricles, and in the hippocampal dentate subgranular zone (SGZ). Cells born in the SVZ migrate to the olfactory bulb. Those born in the SGZ migrate into the granule cell layer. Following 5 or 10 min of global ischemia in the adult gerbil, there is a tenfold increase in the birth of new cells in the SGZ as assessed using bromo-deoxy-uridine incorporation. This begins at 7 days, peaks at 11 days, and decreases thereafter. Over the ensuing month, approximately one-fourth of the newborn cells disappear. Of the remaining cells, 60 % migrate into the granule cell layer where two-thirds of these become NeuN, calbindin, and MAP-2 immunostained neurons. The remaining 40 % of the cells migrate into the dentate hilus where one-fourth of these become glial fibrillary acidic protein–labeled astrocytes. Death of CA1 pyramidal neurons does not stimulate neurogenesis because...
Intracerebral hemorrhage (ICH) activates thrombin, a potent mitogen. Thrombin triggers mitosis by... more Intracerebral hemorrhage (ICH) activates thrombin, a potent mitogen. Thrombin triggers mitosis by modulating several intracellular mitogenic molecules including Src family kinases. These molecules regulate mitogen-activated protein kinases (MAPKs) and cell cycle proteins such as cyclin-dependent kinases (Cdks); and play critical roles in mitogenic signaling pathways and cell cycle progression. Since aberrant cell cycle reentry results in death of mature neurons, cell cycle inhibition appears to be a candidate strategy for the treatment of neurological diseases including ICH. However, this can also block cell cycle (proliferation) of neural progenitor cells (NPCs) and thus impair brain neurogenesis leading to cognitive deficits. We hypothesized that inhibition of cell cycle by blocking mitogenic signaling molecules (i.e., Src family kinase members) blocks cell cycle reentry of mature neurons without injuring NPCs, which will avoid cognitive side effects during cell cycle inhibition treatment for ICH. Our data shows: (1) Thrombin 30U/ml results in apoptosis of mature neurons via neuronal cell cycle reentry in vitro ; (2) PP2 (Src family kinase inhibitor) 0.3 µM attenuates the thrombin-induced neuronal apoptosis via blocking neuronal cell cycle reentry, but does not affect the viability of NPCs at the same doses in vitro ; (3) Intracerebral ventricular thrombin injection (20U, i.c.v.) results in neuron loss in hippocampus and cognitive deficits 5 weeks after thrombin injection in vivo ; (4) PP2 (1mg/kg, i.p.), given immediately after thrombin injection (i.c.v.), blocks the thrombin-induced neuron loss in hippocampus and cognitive deficits, whereas PP2 on its own at the same doses does not affect normal cognition in vivo . These suggest that Src kinase inhibition prevents hippocampal neuron death via blocking neuronal cell cycle reentry after ICH, but does not affect survival of NPCs.
Background and Purpose: Though there are many biomarker studies of plasma and serum in patients w... more Background and Purpose: Though there are many biomarker studies of plasma and serum in patients with aneurysmal subarachnoid hemorrhage (SAH), few have examined cells in blood that might contribute to vasospasm and delayed ischemic neurological deficits (DIND). In this study we evaluate inflammatory and prothrombotic pathways by examining RNA expression in whole blood (including leukocytes, platelets) of SAH patients with vasospasm compared to those without vasospasm. Methods: Adult patients with aneurysmal SAH admitted to UCSF from 2003 to 2010 were enrolled. Patients with vasospasm (n=29) and without vasospasm (n=21) were matched for sex, race/ethnicity and aneurysm treatment method. Diagnosis of vasospasm was made by angiography. RNA expression was measured by Affymetrix Human Exon 1.0 ST Arrays. SAH patients with vasospasm were compared to those without vasospasm by ANCOVA to identify differential gene expression, exon expression and alternatively spliced transcript expression. ...
Neurogenesis in the dentate gyrus of adult rodents is regulated by NMDA receptors, adrenal steroi... more Neurogenesis in the dentate gyrus of adult rodents is regulated by NMDA receptors, adrenal steroids, environmental stimuli, and seizures. To determine whether ischemia affects neurogenesis, newly divided cells in the dentate gyrus were examined after transient global ischemia in adult gerbils. 5-Bromo-2′-deoxyuridine-5′-monophosphate (BrdU) immunohistochemistry demonstrated a 12-fold increase in cell birth in the dentate subgranular zone 1–2 weeks after 10 min bilateral common carotid artery occlusions. Two minutes of ischemia did not significantly increase BrdU incorporation. Confocal microscopy demonstrated that BrdU immunoreactive cells in the granule cell layer colocalized with neuron-specific markers for neuronal nuclear antigen, microtubule-associated protein-2, and calbindin D28k, indicating that the newly divided cells migrated from the subgranular zone into the granule cell layer and matured into neurons. Newborn cells with a neuronal phenotype were first seen 26 d after is...
Small noncoding RNAs play a critical role in regulating messenger RNA throughout brain developmen... more Small noncoding RNAs play a critical role in regulating messenger RNA throughout brain development and when altered could have profound effects leading to disorders such as autism spectrum disorders (ASD). We assessed small noncoding RNAs, including microRNA and small nucleolar RNA, in superior temporal sulcus association cortex and primary auditory cortex in typical and ASD brains from early childhood to adulthood. Typical small noncoding RNA expression profiles were less distinct in ASD, both between regions and changes with age. Typical micro-RNA coexpression associations were absent in ASD brains. miR-132, miR-103, and miR-320 micro-RNAs were dysregulated in ASD and have previously been associated with autism spectrum disorders. These diminished region- and age-related micro-RNA expression profiles are in line with previously reported findings of attenuated messenger RNA and long noncoding RNA in ASD brain. This study demonstrates alterations in superior temporal sulcus in ASD, ...
Preclinical animal models can help guide the development of clinical pediatric and newborn stroke... more Preclinical animal models can help guide the development of clinical pediatric and newborn stroke trials. Data obtained using currently available models of hypoxia-ischemia and focal stroke have demonstrated the need for age-appropriate models. There are age-related differences in susceptibility of the immature brain to oxidative stress and inflammation, as well as in the rate and degree of apoptotic neuronal death. These issues need to be carefully addressed in designing future clinical trials.
Journal of Cerebral Blood Flow & Metabolism, 2001
The current study determined whether short durations of ischemia that produce ischemia-induced to... more The current study determined whether short durations of ischemia that produce ischemia-induced tolerance stimulate glial proliferation in brain. Adult male gerbils were injected with BrdU (50 mg/kg) and dividing cells were detected using immunocytochemistry after sham operations, 2.5 or 5 minutes of global ischemia, or ischemia-induced tolerance. The 2.5-minute ischemia and the ischemia-induced tolerance did not kill hippocampal CA1 pyramidal neurons, whereas the 5-minute ischemia did kill the neurons. At 4 days after 2.5-minute global ischemia, when cell proliferation was maximal, BrdU-labeled cells increased in striatum and in neocortex, but not in hippocampus. The majority of the BrdU-labeled cells were double-labeled with isolectin B4, showing that these dividing cells were primarily microglia or macrophages, or both. Similarly, BrdU-labeled microglia/macrophages were found in striatum and neocortex but not in hippocampus of most animals 4 days after ischemia-induced tolerance (...
These studies show that gene expression changes in most patients by 2 to 3 hours after ischemic s... more These studies show that gene expression changes in most patients by 2 to 3 hours after ischemic stroke, and in all patients studied by 24 hours. (Stroke. 2007;38[part 2]:691-693.)
Stem cells are found throughout the adult mammalian brain, including the subventricular zone (SVZ... more Stem cells are found throughout the adult mammalian brain, including the subventricular zone (SVZ) adja-cent to the lateral ventricles, and in the hippocampal dentate subgranular zone (SGZ). Cells born in the SVZ migrate to the olfactory bulb. Those born in the SGZ migrate into the granule cell layer. Following 5 or 10 min of global ischemia in the adult gerbil, there is a tenfold increase in the birth of new cells in the SGZ as assessed using bromo-deoxy-uridine incorporation. This begins at 7 days, peaks at 11 days, and decreases thereafter. Over the ensuing month, approximately one-fourth of the newborn cells disappear. Of the remaining cells, 60 % migrate into the granule cell layer where two-thirds of these become NeuN, calbindin, and MAP-2 immunostained neurons. The remaining 40 % of the cells migrate into the dentate hilus where one-fourth of these become glial fibrillary acidic protein–labeled astrocytes. Death of CA1 pyramidal neurons does not stimulate neurogenesis because...
Intracerebral hemorrhage (ICH) activates thrombin, a potent mitogen. Thrombin triggers mitosis by... more Intracerebral hemorrhage (ICH) activates thrombin, a potent mitogen. Thrombin triggers mitosis by modulating several intracellular mitogenic molecules including Src family kinases. These molecules regulate mitogen-activated protein kinases (MAPKs) and cell cycle proteins such as cyclin-dependent kinases (Cdks); and play critical roles in mitogenic signaling pathways and cell cycle progression. Since aberrant cell cycle reentry results in death of mature neurons, cell cycle inhibition appears to be a candidate strategy for the treatment of neurological diseases including ICH. However, this can also block cell cycle (proliferation) of neural progenitor cells (NPCs) and thus impair brain neurogenesis leading to cognitive deficits. We hypothesized that inhibition of cell cycle by blocking mitogenic signaling molecules (i.e., Src family kinase members) blocks cell cycle reentry of mature neurons without injuring NPCs, which will avoid cognitive side effects during cell cycle inhibition treatment for ICH. Our data shows: (1) Thrombin 30U/ml results in apoptosis of mature neurons via neuronal cell cycle reentry in vitro ; (2) PP2 (Src family kinase inhibitor) 0.3 µM attenuates the thrombin-induced neuronal apoptosis via blocking neuronal cell cycle reentry, but does not affect the viability of NPCs at the same doses in vitro ; (3) Intracerebral ventricular thrombin injection (20U, i.c.v.) results in neuron loss in hippocampus and cognitive deficits 5 weeks after thrombin injection in vivo ; (4) PP2 (1mg/kg, i.p.), given immediately after thrombin injection (i.c.v.), blocks the thrombin-induced neuron loss in hippocampus and cognitive deficits, whereas PP2 on its own at the same doses does not affect normal cognition in vivo . These suggest that Src kinase inhibition prevents hippocampal neuron death via blocking neuronal cell cycle reentry after ICH, but does not affect survival of NPCs.
Background and Purpose: Though there are many biomarker studies of plasma and serum in patients w... more Background and Purpose: Though there are many biomarker studies of plasma and serum in patients with aneurysmal subarachnoid hemorrhage (SAH), few have examined cells in blood that might contribute to vasospasm and delayed ischemic neurological deficits (DIND). In this study we evaluate inflammatory and prothrombotic pathways by examining RNA expression in whole blood (including leukocytes, platelets) of SAH patients with vasospasm compared to those without vasospasm. Methods: Adult patients with aneurysmal SAH admitted to UCSF from 2003 to 2010 were enrolled. Patients with vasospasm (n=29) and without vasospasm (n=21) were matched for sex, race/ethnicity and aneurysm treatment method. Diagnosis of vasospasm was made by angiography. RNA expression was measured by Affymetrix Human Exon 1.0 ST Arrays. SAH patients with vasospasm were compared to those without vasospasm by ANCOVA to identify differential gene expression, exon expression and alternatively spliced transcript expression. ...
Neurogenesis in the dentate gyrus of adult rodents is regulated by NMDA receptors, adrenal steroi... more Neurogenesis in the dentate gyrus of adult rodents is regulated by NMDA receptors, adrenal steroids, environmental stimuli, and seizures. To determine whether ischemia affects neurogenesis, newly divided cells in the dentate gyrus were examined after transient global ischemia in adult gerbils. 5-Bromo-2′-deoxyuridine-5′-monophosphate (BrdU) immunohistochemistry demonstrated a 12-fold increase in cell birth in the dentate subgranular zone 1–2 weeks after 10 min bilateral common carotid artery occlusions. Two minutes of ischemia did not significantly increase BrdU incorporation. Confocal microscopy demonstrated that BrdU immunoreactive cells in the granule cell layer colocalized with neuron-specific markers for neuronal nuclear antigen, microtubule-associated protein-2, and calbindin D28k, indicating that the newly divided cells migrated from the subgranular zone into the granule cell layer and matured into neurons. Newborn cells with a neuronal phenotype were first seen 26 d after is...
Small noncoding RNAs play a critical role in regulating messenger RNA throughout brain developmen... more Small noncoding RNAs play a critical role in regulating messenger RNA throughout brain development and when altered could have profound effects leading to disorders such as autism spectrum disorders (ASD). We assessed small noncoding RNAs, including microRNA and small nucleolar RNA, in superior temporal sulcus association cortex and primary auditory cortex in typical and ASD brains from early childhood to adulthood. Typical small noncoding RNA expression profiles were less distinct in ASD, both between regions and changes with age. Typical micro-RNA coexpression associations were absent in ASD brains. miR-132, miR-103, and miR-320 micro-RNAs were dysregulated in ASD and have previously been associated with autism spectrum disorders. These diminished region- and age-related micro-RNA expression profiles are in line with previously reported findings of attenuated messenger RNA and long noncoding RNA in ASD brain. This study demonstrates alterations in superior temporal sulcus in ASD, ...
Preclinical animal models can help guide the development of clinical pediatric and newborn stroke... more Preclinical animal models can help guide the development of clinical pediatric and newborn stroke trials. Data obtained using currently available models of hypoxia-ischemia and focal stroke have demonstrated the need for age-appropriate models. There are age-related differences in susceptibility of the immature brain to oxidative stress and inflammation, as well as in the rate and degree of apoptotic neuronal death. These issues need to be carefully addressed in designing future clinical trials.
Journal of Cerebral Blood Flow & Metabolism, 2001
The current study determined whether short durations of ischemia that produce ischemia-induced to... more The current study determined whether short durations of ischemia that produce ischemia-induced tolerance stimulate glial proliferation in brain. Adult male gerbils were injected with BrdU (50 mg/kg) and dividing cells were detected using immunocytochemistry after sham operations, 2.5 or 5 minutes of global ischemia, or ischemia-induced tolerance. The 2.5-minute ischemia and the ischemia-induced tolerance did not kill hippocampal CA1 pyramidal neurons, whereas the 5-minute ischemia did kill the neurons. At 4 days after 2.5-minute global ischemia, when cell proliferation was maximal, BrdU-labeled cells increased in striatum and in neocortex, but not in hippocampus. The majority of the BrdU-labeled cells were double-labeled with isolectin B4, showing that these dividing cells were primarily microglia or macrophages, or both. Similarly, BrdU-labeled microglia/macrophages were found in striatum and neocortex but not in hippocampus of most animals 4 days after ischemia-induced tolerance (...
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