Project description:Dysregulated long non-coding RNAs (lncRNAs) have been shown to contribute to the pathogenesis of ischemic stroke. However, the potential role of lncRNAs in post-stroke microglial reactivation remains largely unknown. Here, we uncovered that lncRNA-U90926 was significantly increased in the microglia exposed to ischemia/reperfusion in vivo and in vitro. In addition, adenovirus associated virus (AAV)-mediated microglial U90926 silencing alleviated neurological deficits and reduced infarct volume in experimental stroke mice. Microglial U90926 knockdown could reduce the infiltration of neutrophils into ischemic lesion site, which might be attributed to the downregulation of C-X-C motif ligand 2 (CXCL2). Mechanistically, U90926 directly bound to malate dehydrogenase (MDH2) and competitively inhibited MDH2-mediated decay of CXCL2 mRNA. Taken together, our study demonstrated that microglial U90926 aggravated ischemic brain injury via facilitating neutrophil infiltration, suggesting that U90926 might be a potential biomarker and therapeutic target for ischemic stroke.
Project description:Analysis of microglial gene expression profiles after ischemic stroke. Stroke is a complicated disease caused by the interaction of multiple celltypes. Results provide new insights into the molecular mechanisms underlying microglial activation after ischemic stroke.
Project description:Ischemic stroke is a common acute CNS disorder leading to nearly half a million deaths per year in Europe. The high mortality is primarily owed to the limited treatment options of restoring blood flow in a narrow time window of several hours. Furthermore, inflammatory processes in the days and weeks after ischemic stroke contribute to tissue loss and neurological deficits. The key cells that influence and control this inflammatory cascade are microglia, the innate immune cells of the CNS. Microglia can be influenced and activated by e.g. lipopolysaccharide (LPS),a bacterial cell membrane component. It has been previously shown, that repetitive LPS stimuli prior to infarction (termed immunological preconditioning) lead to reduced infarct volumina in mouse models of ischemic stroke. Furthermore, our laboratory has shown, that phosphoinositide-3 kinase gamma mediates microglial functions after LPS-preconditioning. Hence, the aim of this work was to characterize proteomic alterations in microglia with (I) ischemic stroke in general in the tMCAO (transient middle cerebral artery occlusion) mouse model of ischemic stroke, (II) the influence of LPS-preconditioning on microglial proteomic alterations after tMCAO and (III) the role of PI3Ky in the microglial proteomic changes after tMCAO and preconditioning. This was done by a single LPS injection 3 days before tMCAO in wildtype mice and mice with PI3Ky knockout or knockin of the kinase dead form of PI3Ky.
Project description:Microglia are resident CNS immune cells that are active sensors in healthy brain and versatile effectors under pathological conditions. Cerebral ischemia induces a robust neuroinflammatory response that includes marked changes in the gene expression and phenotypic profile of a variety of endogenous CNS cell types (astrocytes, neurons, microglia) as well as an influx of leukocytic cells (neutrophils, macrophages, T-cells) from the periphery. Many molecules and conditions can trigger a transformation of ârestingâ (or surveying) microglia to an âactivatedâ (alerted/reactive) state. Here we review recent developments in the literature that relate to microglial activation in the experimental setting of in vitro and in vivo ischemia. We also present new data from our own laboratory demonstrating the direct effects of in vitro ischemic conditions on the microglial phenotype and genomic profile. Emphasis is placed on the role of specific molecular signaling systems such as hypoxia inducible factor-1 (HIF-1) and toll-like receptor-4 (TLR4) in regulating the microglial response in this setting. We then review histological and recent novel radiological data that confirms a key role for microglial activation in the setting of ischemic stroke in humans. We discuss recent progress in the pharmacological and molecular targeting of microglia in acute ischemic stroke. Finally, we explore how recent studies on ischemic preconditioning have increased interest in preemptively targeting microglial activation in order to reduce stroke severity. 12 arrays, 4 experimental groups, 3 replicates in each group, CN is control normoxia, CH is control hypoxia, TN is TLR4 knockout normoxia, TH is TLR4 knockout hypoxia.
Project description:The purpose of this project was to elucidate gene expression in the peripheral whole blood of acute ischemic stroke patients to identify a panel of genes for the diagnosis of acute ischemic stroke. Peripheral blood samples were collected in Paxgene Blood RNA tubes from stroke patients who were >18 years of age with MRI diagnosed ischemic stroke and controls who were non-stroke neurologically healthy. The results suggest a panel of genes can be used to diagnose ischemic stroke, and provide information about the biological pathways involved in the response to acute ischemic stroke in humans. Total RNA extracted from whole blood in n=39 ischemic stroke patients compared to n=24 healthy control subjects.
Project description:PGC-1α overexpression in microglia protects against ischemia-induced brain damage in mice. To investigate the underlying mechanism of PGC-1α, we have employed whole mRNA microarray expression profiling as a discovery platform to identify genes with the potential to change the microglial function. Indeed, PGC-1α overexpression alters the gene expression profiles of microglia after AIS, this suggested that microglial PGC-1α might play an important role after ischemic stroke.
Project description:We performed a genome-wide methylation study in whole-blood DNA from 404 ischemic stroke patient cohort, distributed across 3 ischemic stroke subtypes: Large-artery atherosclerosis (n=132), Small-artery disease (n=141) and Cardio embolic (n=127) . Illumina HumanMethylation450 BeadChip array was used to measure DNA methylation in CpG sites. We performed a genome-wide methylation study in whole-blood DNA from 185 ischemic stroke patient cohort. Illumina HumanMethylation450 BeadChip array was used to measure DNA methylation in CpG sites.