MiRNA profiling of control and ischemic samples in vitro and in vivo
ABSTRACT: miRNA microarray profiling of primary cortical neurons exposed to 4h oxygen and glucose deprivation (OGD) in vitro. RNA samples collected at 8h post-OGD terminaion. miRNAs were also profiled in mice exposed to 3- vessel occlusion model of stroke. RNA samples collected from contralateral (control) and ipsilateral (infarct) sides of the brain following 24h of reperfusion. Comparison of control and ischemic samples across 3 biological replicates for both in vitro and in vivo samples. In vitro cultures consisted of primary cortical neurons derived from E17 rat Wistar embryos. In vivo samples were obtained from C57bl/6 mice exposed to three-vessel occlusion.
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:In this study we sought to determine the effect of overexpressing the SUMOylation E2 conjugase Ubc9 on the response of murine Neural Stem Cells (NSCs) to oxygen-glucose-deprivation and restoration of oxygen/glucose (OGD/ROG). We established stably-expandable lines of NSCs from the subventricular zones (SVZ) of adult wild-type mice (WT NSCs) and Ubc9-overexpressing mice (Ubc9 NSCs) and profiled their transcriptional changes in response to OGD/ROG as well as in response to differentiation.
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-ventricularly 30min post-ischemia induction to determine its efficacy in reduction of neuronal damage in terms of infarct volume. miRNA microarray analysis was performed on Exiqon 5th generation - hsa, mmu & rno (Product no: 208300-A) to compliment our existing gene expression microarray data [GSE23651]. Arrays were run as dual colour (Hy3: Sample, and Hy5: Common sample reference pool). 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 plus i.c.v.injection of 30mM ZM447439 in 80% DMSO; n=4). Supplementary file: Project_Summary_Report.txt The percentages listed in the top row are present-call rates, i.e. number of identified miRNAs compared to number of miRNAs on array.
Project description:The present study has used whole-rat genome microarray expression profiling to identify genes whose expression is significantly altered in hippocampal neuronal cultures submitted to oxygen and glucose deprivation (OGD), an established in vitro model for cerebral global ischemia that is suitable for investigations at the molecular level. To do so, total RNA was extracted from hippocampal neuronal cultures at an early (7h) and delayed (24h) time point after OGD, as well as from control neurons. Analysis of gene ontology showed that OGD followed by 7h or 24h of recovery induces changes in the expression levels of genes related with inflammation, response to oxidative stress, metabolism, apoptosis, synaptic proteins and ion channels and, importantly, genes that show different expression levels are mainly specific to one of the two time points of recovery analyzed. The expression levels of several genes were confirmed by qPCR and were in good agreement with the microarray data, showing that the combined use of the OGD model and the microarray technology can be a useful tool for the study molecular mechanisms contributing to the neuronal demise after transient global ischemia. Ischemia induced gene expression in primary hippocampal neuronal rat cultures was measured at 7 and 24 hours after exposure to Oxygen and Glucose deprivation (OGD). Three independent experiments were performed at each time (7 or 24 hours) as independent biological replicates.
Project description:The human immortalized brain endothelial cell line hCMEC/D3 is considered an in vitro model of the blood-brain-barrier. We aimed to characterize changes in the secretome of hCMEC/D3 subjected to oxygen and glucose deprivation (OGD) by SILAC, in order to identify new proteins involved in ischemia-triggered blood-brain-barrier disruption and test their potential as blood biomarkers for ischemic stroke diagnosis. After SILAC analysis, 19 proteins were found differentially secreted between OGD and normoxia/normoglycemia conditions (Fold Change>|1.4| and peptide count≥2). Protein folding and nucleic acid binding were the main molecular functions and epithelial adherens junctions and aldosterone signaling appeared as the main canonical pathways represented by OGD-secreted proteins. ANXA1, CLUS, IGFBP2, PRDX3, TIMP2 and COL1A2 were replicated by western blotting in 9 independent cell cultures. Five replicated proteins were analyzed in human serum samples of 38 ischemic stroke patients compared to 18 stroke-mimicking conditions and 18 healthy controls by ELISA. IGFBP2 showed increased blood levels when strokes were compared with stroke-mimicking patients (p<0.1). In conclusion, we characterized changes in the secretome of hCMEC/D3 after an ischemic insult and highlighted some candidates to become biomarkers for ischemic stroke diagnosis related to blood-brain-barrier disruption.
Project description:TNF/TNFRI signaling has previously been shown to exert neuroprotective effects after brain ischemic injury. However, the detailed pathways involved remain unidentified. This study aims to identify key neuroprotective molecules activated by TNFRI after permanent ischemic injury in mice. Microarray analysis of the ipsilateral hemispheres of WT and TNFRI knockout at early time points (3 and 6 hours) after the middle cerebral artery occlusion mice were chosen to study the CNS response to injury without significant immune infiltration. Using the ATLAS mouse cDNA arrays that include known genes representative of multiple pathways, we identify novel protective pathways triggered by TNFRI signaling after ischemia. Keywords: brain, ischemic lesion, comparison between WT and TNFRI knockout mice, cDNA array, two different time points (3 and 6 h) RNA was extracted from WT (n=2) and TNFRI KO (n=2) mice at each time point studied (3 and 6 h after ischemia). For each individual sample two hybridisations were performed.
Project description:Complete global brain ischemia (CGBI) and reperfusion occur following resuscitation from cardiac arrest. Different brain neurons are selectively vulnerable to CGBI: pyramidal neurons of hippocampal CA3 survive 10 min CGBI but those of CA1 die at 3 days following 10 min CGBI. CA3 neurons are expected to have more robust stress responses and repair responses than CA1 neurons. We used microarrays to compared total and polysome-bound mRNAs in CA1 and CA3 at 8 hr reperfusion after 10 min CGBI in Long Evans male rats to ascertain differences in total vs polysome-bound gene expression. Male Long Evans rats were subjected to (1) sham operation (non-ischemic control, NIC) or normothermic CGBI of 10 min followed by 8 hr reperfusion (8R). Hippocampal CA1 and CA3 were dissected. n = 5 CA1 or CA3 were pooled to give a single replicate and there were 3 or 4 replicates per group. Post-mitochondrial supernatant (PMS) was prepared. Twenty percent of PMS was TRIzol extracted to give total RNA. The remainder was run on a 20% sucrose pad to isolate polysome pellets, which were also TRIzol extracted to give polysome RNA. Total and polysome RNA were then run on Affymetrix Rat Gene 2.0 microarrays.
Project description:Ischemic tolerance can be induced by numerous preconditioning stimuli, including various Toll-like receptor (TLR) ligands. We have shown previously that systemic administration of the TLR4 ligand, lipopolysaccharide (LPS) or the TLR9 ligand, unmethylated CpG ODNs prior to transient brain ischemia in mice confers substantial protection against ischemic damage. To elucidate the molecular mechanisms of preconditioning, we compared brain and blood genomic profiles in response to preconditioning with these TLR ligands and to preconditioning via exposure to brief ischemia. The experiment is a comparison of multiple treatment groups with sampling at multiple time points. The objective is to identify differentially regulated genes associated with preconditioning. Time points are examined both following preconditioning alone and following subsequent ischemic challenge (middle cerebral artery occlusion (MCAO)). Brain ipsilateral cortex tissue and blood were collected and processed from each animal. 6 experimental conditions: (n=3-4 mice/condition) LPS treated (i.p. 0.2mg/kg) + ischemic challenge (45min MCAO) CpG treated (i.p. 0.8mg/kg) + ischemic challenge (45min MCAO) Saline treated (i.p.) + ischemic challenge (45min MCAO) brief ischemia (12 min MCAO) + ischemic challenge (45min MCAO) Sham of brief ischemia (12 min) + ischemic challenge (45min MCAO) Non-treated + ischemic challenge (45min MCAO) Time points: Pre-ischemic challenge 3hr 24hr 72hr Post-ischemic challenge 3hr 24hr Unhandled (6 mice)-BASELINE
Project description:Oxygen-glucose deprivation (OGD) is a cellular phenomenon consistently observed upon occurrence of ischemic stroke which eventually results in neuronal death. Neuronal cell death after ischemia takes place via two distinct processes, necrosis and apoptosis. Apoptosis, programmed cell death, is denoted by chromatin condensation, nuclear blebbing, cellular shrinkage, and DNA fragmentation. Unlike apoptosis, cellular swelling and lysis is suggestive of necrosis. However, these two processes are related not only to the severity but also to the duration of ischemia. Microarray analysis was carried out using 20 Illumina mouse Ref8V1.1 genechip arrays. The assignment of the arrays was as follows: Controls (n=5); exposure to OGD for 10min, 5h, 8h, 15h and 24 h (n=3 respectively).
Project description:Post-ischemic microglial activation may contribute to neuronal damage through the release of large amounts of pro-inflammatory cytokines and neurotoxic factors. The involvement of microRNAs (miRNAs) in the pathogenesis of disorders related to the brain and central nervous system has been previously studied, but it remains unknown whether the production of pro-inflammatory cytokines is regulated by miRNAs.BV-2 and primary rat microglial cells were activated by exposure to oxygen-glucose deprivation (OGD). Global cerebral ischemia was induced using the four-vessel occlusion (4-VO) model in rats. Induction of pro-inflammatory and neurotoxic factors, such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and nitric oxide (NO), were assessed by ELISA, immunofluorescence, and the Griess assay, respectively. The miRNA expression profiles of OGD-activated BV-2 cells were subsequently compared with the profiles of resting cells in a miRNA microarray. BV-2 and primary rat microglial cells were transfected with miR-181c to evaluate its effects on TNF-α production after OGD. In addition, a luciferase reporter assay was conducted to confirm whether TNF-α is a direct target of miR-181c.OGD induced BV-2 microglial activation in vitro, as indicated by the overproduction of TNF-α, IL-1β, and NO. Global cerebral ischemia/reperfusion injury induced microglial activation and the release of pro-inflammatory cytokines in the hippocampus. OGD also downregulated miR-181c expression and upregulated TNF-α expression. Overproduction of TNF-α after OGD-induced microglial activation provoked neuronal apoptosis, whereas the ectopic expression of miR-181c partially protected neurons from cell death caused by OGD-activated microglia. RNAinterference-mediated knockdown of TNF-α phenocopied the effect of miR-181c-mediated neuronal protection, whereas overexpression of TNF-α blocked the miR-181c-dependent suppression of apoptosis. Further studies showed that miR-181c could directly target the 3'-untranslated region of TNF-α mRNA, suppressing its mRNA and protein expression.Our data suggest a potential role for miR-181c in the regulation of TNF-α expression after ischemia/hypoxia and microglia-mediated neuronal injury.