Project description:Here, we analyzed ischemic stroke induced changes in microRNA levels in mouse brain using permanent cerebral ischemia model. We performed enrichment of small RNAs from peri-ischemic brain region for RNA sequencing and present data set containing several small RNA species to facilitate the discovery of ischemia induced changes in non-coding RNAs.
Project description:Both acute and chronic stress have significant impact on brain functions. The amygdala is essential in mediating stress responses, but how its transcriptomic dynamics change under stress remains elusive. To overcome the difficulties in detecting subtle stress-induced changes by evaluating total RNA using classic RNA sequencing, we conducted thiol-labeled RNA sequencing (SLAM-seq). We injected 4-thiouridine (4sU) into mouse amygdala followed by SLAM-seq to detect nascent mRNA induced by acute and chronic restraint stress, and found that SLAM-seq could label actively transcribed genes in the major neuronal and glial subtypes. Using SLAM-seq, we found that chronic stress led to higher turnover of a group of genes associated with myelination, and this finding is confirmed by immunostaining which showed increased myelination in the chronically stressed amygdala. Additionally, genes detected by SLAM-seq and RNA-seq only partially overlapped, with SLAM-seq particularly sensitive to transcriptional changes in genes with high basal transcription levels. Thus, by applying SLAM-seq in vivo, we obtained a rich dataset of nascently transcribed genes in the amygdala under stress, and revealed distinct transcriptional dynamics associated with acute and chronic stress.
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:Transient brain ischemia massively activates global SUMOylation. A large fraction of SUMO targets are nuclear proteins involved in gene expression. However, gene expression profile modulated by ischemia-induced SUMOylation has not been studied. Using a SUMO knockdown (SUMO-KD) mouse model and microarray technique, we investigated how SUMOylation modulated gene expression after brain ischemia. Wild-type and SUMO-KD mice were subjected to transient forebrain ischemia or sham surgery. The hippocampal CA1 subfield samples collected at 3 hours reperfusion were analyzed using Affymetrix microarrays.
Project description:Focal ischemia is triggered by the sudden significant reduction of blood supply to the brain, as a result of either the rupture or occlusion by thrombus/embolism of a blood vessel in the brain. Permanent focal ischemia occurred when blood supply to a specific part of the brain is impeded without reperfusion. Despite major steps achieved in the elucidation of the patho-physiology of cerebral ischemia, the available therapeutic avenues for acute ischemic stroke remain scarce. Cell cycle re-activation has been revealed as a novel signaling pathway during permanent focal ischemia. As such, non-specific aurora kinase inhibitor ZM447439, has been injected intracranial-ventricularly30min post-ischemia induction to determine its efficacy in reduction of neuronal damage in terms of infarct volume. Microarray analysis was performed on Illumina Rat Ref12V1 beadchips. Right cortex RNA samples were collected at two time-points (8h and 24h ) respectively for all three experimental conditions: Sham (n=4), vehicle (i.e. ischemic injury with i.c.v. injection 80% DMSO; n=4) and treatment (injury plusi.c.v.injection of 30mM ZM447439 in 80% DMSO; n=4).
Project description:Transient brain ischemia massively activates global SUMOylation. A large fraction of SUMO targets are nuclear proteins involved in gene expression. However, gene expression profile modulated by ischemia-induced SUMOylation has not been studied. Using a SUMO knockdown (SUMO-KD) mouse model and microarray technique, we investigated how SUMOylation modulated gene expression after brain ischemia.
Project description:RNA-Seq transcriptome comparison of the following cell populations (n=3-4 independent samples per cell population): a) CD11c-eYFP+ cells FACS sorted from brain of female adult mice 4 days after cerebral ischemia, b) CD11c-eYFP+ cells FACS sorted from brain of female parabiotic mice 4 days after cerebral ischemia c) CX3CR1+ microglia sorted from the ischemic brain of female CX3CR1CreERT2-ROSA26 tdTomato mice. Purpose: The goal of this study is to compare the transcriptome profile (RNA-Seq) of infiltrating cD11c-eYFP+ cells and microglia, both collected from ischemic brains of mice. Methods: RNA samples were obtained from FACS sorted eYFP+ cells of the ipsilateral brain hemisphere of CD11c-eYFP mice 4 days post-ischemia, the ipsilateral brain hemisphere of CD11c-eYFP/WT parabiotic mice 4 days post-ischemia, and from microglial cells sorted from the ipsilateral brain hemisphere of Cx3cr1CreERT2:ROSA26dTomato mice 4 days post-ischemia. NGS was performed (RNA-Seq) to compare the transcriptome of these populations. Results: the populations we compared clearly separated the differentially expressed genes in an unsupervised cluster analysis. 1509 genes were overrepresented in microglia and 1183 genes were overrepresented in CD11c-eYFP+ cells in the ischemic brain. Conclusions: Our study is the first comparative analysis of the transcriptomes of microglia and the infiltrating CD11c-eYFP+ cells derived from the ischemic brain of mice. The results show that the infiltrating CD11c-eYFP cell population in the ischemic brain tissue of parabiotic mice displays overrepresentation of genes typical of dendritic cells, immune functions, and ClassII antigen presentation, amongst others, that are not found represented in microglia.
Project description:In the current study, we characterized the global miRNA expression profile in mouse pancreatic acinar cells during acute pancreatitis using next-generation RNA-Sequencing. We identified 330 known and 6 novel miRNAs being expressed in mouse pancreatic acinar cells. At basal state, miR-148a-3p, miR-375-3p, miR-217-5p, miR-216a-5p were among the most abundantly expressed whereas miR-24-5p and miR-421-3p were least abundant. Treatment of acinar cells with supra-maximal caerulein or bile acid induced numerous changes in miRNA expression levels. In particular, we observed significant upregulation of miR-21-3p in these experiments, which was further, confirmed using mouse models of acute pancreatitis. In summary, this is the first comprehensive analysis of miRNA expression in healthy mouse pancreatic acinar cells and how this expression signature changes in acute pancreatitis.