Project description:Microglial activation after stroke may lead to development of inflammation-induced brain damage. Here we uncover a ribosome-based mechanism/check point involved in control of the innate immune response and microglial activation orchestrated by RNA binding protein SRSF3. Using an in vivo model-system for analysis of the dynamic translational state of microglial ribosomes with mRNAs as input and newly synthesized peptides as an output, we found a marked dissociation of microglia mRNA and protein signatures following ischemic stroke. Highly up-regulated and ribosomes associated mRNAs were not translated 24hrs after stroke resulting in two distinct microglial molecular signatures, a highly specialized pro-inflammatory mRNA and immunomodulatory/homeostatic protein signatures. We found that this is due to specific translational suppression of highly expressed mRNAs through a 3'UTR-mediated mechanism involving the RNA binding protein SRSF3. This discovery suggests avenues for therapeutic modulation of innate immune response in resident microglia after stroke.
Project description:Infection is a major complication and cause of mortality and morbidity after acute stroke however the mechanisms are poorly understood. After experimental stroke the microarchitecture and cellular composition of the spleen are extensively disrupted resulting in deficits to immune function. We used microarray to determine differentially expressed genes in the spleens of mice after experimental stroke to determine contributers to immunosuppression after stroke. We extracted RNA from spleens from 3 mice 5 d after experimental stroke when we have shown peak disruption to cellular composition and also from spleens from 2 sham-operated control mice for comparison.
Project description:Infection is a major complication and cause of mortality and morbidity after acute stroke however the mechanisms are poorly understood. After experimental stroke the microarchitecture and cellular composition of the spleen are extensively disrupted resulting in deficits to immune function. We used microarray to determine differentially expressed genes in the spleens of mice after experimental stroke to determine contributers to immunosuppression after stroke.
Project description:To date, miRNA expression studies on cerebral ischemia in both human and animal models have focused mainly on acute phase of ischemic stroke. In this study, we present the roles played by microRNAs in the spontaneous recovery phases in cerebral ischemia using rodent stroke models. In this study presented here, Middle Cerebral Artery Occlusion stroke model was established by using embolus and the brain samples of stroke model were harvested at 0hrs, 3hrs, 6hrs, 12hrs, 24hrs, 48hrs, 72hrs, 120hrs and 168hrs. RNAs were extracted from these samples and microRNA array and mRNA array were performed.
Project description:To date, miRNA and mRNA expression studies on cerebral ischemia in both human and animal models have focused mainly on acute phase of ischemic stroke. In this study, we present the roles played by microRNAs in the spontaneous recovery phases in cerebral ischemia using rodent stroke models. In this study presented here, Middle Cerebral Artery Occlusion stroke model was established by using embolus and the brain samples of stroke model were harvestd at 0hrs, 3hrs, 6hrs, 12hrs, 24hrs, 48hrs, 72hrs, 120hrs and 168hrs. RNAs were extracted from these samples and microRNA array and mRNA array were performed.
Project description:Stroke is a prevalent disorder representing the third leading cause of death and major cause of disability. Post-stroke epilepsy (PSE) has been recognized as a common clinical issue after stroke, accounting for 30-40% of the causes of epilepsy among older adults. In this study, we determined GABAA receptor-mediated seizure susceptibility after PT cerebral stroke in aged mice. Young adult mice around 10 weeks of age are widely used in stroke experiments. However, as most strokes are diagnosed in the elderly and PSE has been recognized as a common clinical incidence after stroke, we utilized photothrombosis (PT) model of cerebral ischemia and examined seizure susceptibility and brain injury using combined behavioral (video) and EEG monitoring and histological (MRI) assessments. To investigate GABAA receptor-mediated convulsive/non-convulsive seizures, lower-doses of pentylenetetrazol (PTZ) was injected. PTZ susceptibility in aging mice increased compared to young adults. One month after PT stroke, aged PT stroke mice exhibited severe convulsive seizures (late-onset). These findings exhibited the increase of GABAA receptor-mediated seizures susceptibility in PT stroke aging mice, but not in young adults.
Project description:This study determined the influence of myeloid cell Trim59 deficiency on experimental stroke outcomes and the cerebral proteomic profile using myeloid cell Trim59 conditional knockout (Trim59-cKO) mice, the middle cerebral artery occlusion/reperfusion ischemic model, and a label-free quantitative proteomic profiling technique.
Project description:Ischemic stroke is one of the leading causes of mortality and major healthcare and economic burden. It is a well recognized disease of aging, yet it is unclear how the age-dependent vulnerability occurs and what are the underlying mechanisms. To address these issues, we performed a comprehensive RNA-Seq analysis of aging, ischemic stroke and their interaction using a model of permanent middle cerebral artery occlusion (MCAO) in 3 and 18 month old female mice. We assessed differential gene expression across injury status and age, estimated cell type proportion changes, assayed the results against a range of transcriptional signatures from the literature and performed unsupervised co-expression analysis, identifying modules of genes with varying response to injury. We uncovered selective vulnerability of neuronal populations and increased activation of type-I interferon (IFN-I) signaling and several other inflammatory pathways in aged mice. We extended these findings via targeted expression analysis in tissue as well as acutely purified cellular populations to show differential temporal dynamics of IFN-I signaling between age groups and contribution of individual cell types. Together, these results paint a picture of ischemic stroke as a complex age related disease and provide insights into interaction of aging and stroke on cellular and molecular level.