Project description:Blood monocytes/macrophages infiltrate the brain after ischemic stroke and critically influence brain injury and regeneration. We investigated stroke-induced transcriptomic changes of monocytes/macrophages by RNA sequencing profiling, using a mouse model of permanent focal cerebral ischemia. Compared to non-ischemic conditions, brain ischemia induced only moderate genomic changes in blood monocytes, but triggered robust genomic reprogramming in monocytes/macrophages invading the brain. Surprisingly, functional enrichment analysis of the transcriptome of brain macrophages revealed significant overrepresentation of biological processes linked to neurovascular remodeling, such as angiogenesis and axonal regeneration, as early as 5 days after stroke, suggesting a previously underappreciated role for macrophages in initiating post-stroke brain repair. Upstream Regulator analysis predicted peroxisome proliferator-activated receptor gamma (PPARγ) as a master regulator driving the transcriptional reprogramming in post-stroke brain macrophages. Importantly, myeloid cell-specific PPARγ knockout (mKO) mice demonstrated lower post-stroke angiogenesis and neurogenesis than wild-type mice, which correlated significantly with the exacerbation of post-stroke neurological deficits in mKO mice. Collectively, our findings reveal a novel repair-enhancing transcriptome in brain macrophages during post-stroke neurovascular remodeling. As a master switch controlling genomic reprogramming, PPARγ is a rational therapeutic target for promoting and maintaining beneficial macrophage functions, facilitating neurorestoration, and improving long-term functional recovery after ischemic stroke.
Project description:Ischemic stroke causes extensive neuronal cell death. Antithrombotic agents and rehabilitation are the primary treatment options but have limited efficacy. Therefore, to achieve radical neurological improvement, practical neuroregenerative technologies must be developed. Recently, direct chemical reprogramming using small molecules to transdifferentiate somatic cells into neurons has garnered much attention. We investigated the possibility of applying this technology for the treatment of ischemic stroke. During the acute phase of ischemic stroke, circulating monocytes increase chemotaxis and accumulate in the infarct area through the disrupted blood-brain barrier, where they differentiate into macrophages involved in inflammation and remodeling. Direct reprogramming of these monocyte-derived macrophages into neuronal cells in vivo is theoretically possible with the administration of small-molecule drugs. However, the efficacy of this neuroregenerative therapy cannot be verified because the optimal chemical compounds that convert macrophages into neurons have not yet been identified.
Project description:Macrophages play an important role in the pathological process of stroke. We used single cell RNA sequencing (scRNA-seq) to analyze the diversity of infiltrated macrophages from ischemic brain after stroke.
Project description:Intermittent fasting is previously reported to exhibit neuroprotection against experimental ischemic stroke. However, the detailed understanding of protection mechanisms are lacking. By observing the overall transcriptomic changes in each timepoint of ischemic stroke would benefit the understanding of underlying active pathways and mechanisms. Here, we conduct experimental MCAO ischemic stroke on mice exposed to different daily intermittent fasting method to compare not only among the ischemic stroke timepoints but also the efficacy of different intermittent fasting interventions. Our current study presented the transcriptomic changes for the first time in specific timepoints of ischemic stroke as well as under the condition of intermittent fasting. A number of neuroprotective mechanisms-related genes were significantly affected by intermittent fasting conditions in differential manners.
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: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.
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: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.
Project description:The current treatment options for ischemic stroke aim to achieve reperfusion but are time critical. Novel therapeutic approaches that can be given beyond the limited time window of 3 - 4.5 hours are still an unmet need to be addressed to improve stroke outcome. The lack of oxygen and glucose in the area of ischemic injury initiates a pathological cascade leading to blood-brain barrier (BBB) breakdown, inflammation and neuronal cell death, a process that may be intercepted to limit stroke progression. Pericytes located at the blood/brain interface are one of the first responders to hypoxia in stroke and therefore a potential target cell for early stroke interventions. Using single-cell RNA sequencing in a mouse model of permanent middle cerebral artery occlusion, we investigated the temporal differences in transcriptomic signatures in pericytes at 1, 12, and 24 hours after stroke compared to the contralateral hemisphere. Our results reveal a stroke-specific subcluster of pericytes that is present at 12 and 24 hours and characterized by the upregulation of genes mainly related to cytokine signalling and immune response. This study identifies temporal transcriptional changes in the acute phase of ischemic stroke that reflect the early response of pericytes to the ischemic insult and its secondary consequences and may constitute potential future therapeutic targets.