Project description:This data set shows dramatic changes in gene expression in microglia isolated from C57Bl6/J mice subjected to transient middle cerebral artery occlusion, as compared to those subjected to sham surgery. Mice deficient in Mincle (Clec4e-/-) showed significantly improved injury outcomes 3 and 7 days after transient middle cerebral artery occlusion. However, when comparing changes in gene expression in microglia 24 hours after blood reperfusion, there were no differences between wild-type and Clec4e-/- mice, indicating that Mincle does not participate in early microglial activation. Wild type and Mincle knock-out (Clec4e-/-) mice. After 1 h of transient middle cerebral artery occlusion (tMCAO) and 24 h of reperfusion, mice were perfused with PBS, their brains dissected, and 2 ipsilesional hemispheres (with cerebellum and brainstem removed) pooled for microglia isolation. For sham-operated animals, the whole forebrain was used and brains were not pooled. After myelin separation by Percoll gradient centrifugation, around 80,000 CD45intermediate, CD11b+ microglial cells were sorted from each sample. Sham samples n=3, tMCAO samples n=5.
Project description:This data set shows dramatic changes in gene expression in microglia isolated from C57Bl6/J mice subjected to transient middle cerebral artery occlusion, as compared to those subjected to sham surgery. Mice deficient in Mincle (Clec4e-/-) showed significantly improved injury outcomes 3 and 7 days after transient middle cerebral artery occlusion. However, when comparing changes in gene expression in microglia 24 hours after blood reperfusion, there were no differences between wild-type and Clec4e-/- mice, indicating that Mincle does not participate in early microglial activation.
Project description:Immune responses and neuroinflammation occurring after acute ischemic stroke (AIS) are closely related to brain injury. Histone lactylation is a metabolic stress-related histone modification that participates in the pathogenesis of various diseases. However, the role of histone regulation in cerebral ischemic stroke remains unknown. In this study, a transient middle cerebral artery occlusion (tMCAO/R) model and an oxygen–glucose deprivation and reoxygenation (OGD/R) model were used to simulate in vivo/in vitro ischemia–reperfusion injury. The underlying mechanism of microglial histone lactylation was investigated using microglia-specific SMEK1-overexpressing mice and BV2 cells. The results showed that lactate overload resulted in elevated histone lactylation after AIS. Decreased SMEK1 expression in microglia after ischemic stroke was associated with increased lactate levels and subsequent neuroinflammation. Microglia-specific SMEK1 deficiency in microglia after ischemia can promote lactate production by inhibiting the pyruvate dehydrogenase kinase 3-pyruvate dehydrogenase (PDK3-PDH) pathway. Specifically, H3 lysine 9 lactylation (H3K9la) activated Ldha and Hif-1α transcription in microglia and promoted glycolysis. SMEK1-overexpressing mice exhibited better neurologic recovery after ischemic stroke than control mice. Mechanistically, we provided new evidence that microglial histone lactylation promoted glycolysis in ischemia‒reperfusion injury and elucidated the potential role of SMEK1 as an upstream regulatory molecule in histone lactylation after cerebral ischemia. According to our results, microglial SMEK1 may be potential therapeutic targets for AIS.
Project description:We inflicted TBI to chemokine-deficient mouse lines in order to establish involvement of various signalling pathways that may be addressed therapeutically. Interacting chemokine pathways in brain regulate distinct inflammatory cells. Activated microglia are separate from invading phagocytes and dendritic cells. Findings show potential targets to interfere with specific inflammatory responses after brain injury.
Project description:We inflicted TBI to chemokine-deficient mouse lines in order to establish involvement of various signalling pathways that may be addressed therapeutically. Interacting chemokine pathways in brain regulate distinct inflammatory cells. Activated microglia are separate from invading phagocytes and dendritic cells. Findings show potential targets to interfere with specific inflammatory responses after brain injury. TBI was carried out in Ccl3-/- and Ccr2-/- mice, total RNA prepared from injured cerebral neocortex after three days. RNA samples were from uninjured Ccl3-/- and Ccr2-/- mice as reference for hybridization on Affymetrix microarrays.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Translational research is commonly performed in the C57B6/J mouse strain, chosen for its genetic homogeneity and phenotypic uniformity. Here, we evaluate the suitability of the white-footed deer mouse (Peromyscus leucopus) as a model organism for aging research, offering a comparative analysis against C57B6/J and diversity outbred (DO) Mus musculus strains. Our study includes comparisons of body composition, skeletal muscle function, and cardiovascular parameters, shedding light on potential applications and limitations of P. leucopus in aging studies. Notably, P. leucopus exhibits distinct body composition characteristics, emphasizing reduced muscle force exertion and a unique metabolism, particularly in fat mass. Cardiovascular assessments showed changes in arterial stiffness, challenging conventional assumptions and highlighting the need for a nuanced interpretation of aging-related phenotypes. Our study also highlights inherent challenges associated with maintaining and phenotyping P. leucopus cohorts. Behavioral considerations, including anxiety-induced responses during handling and phenotyping assessment, pose obstacles in acquiring meaningful data. Moreover, the unique anatomy of P. leucopus necessitates careful adaptation of protocols designed for Mus musculus. While showcasing potential benefits, further extensive analyses across broader age ranges and larger cohorts are necessary to establish the reliability of P. leucopus as a robust and translatable model for aging studies.
Project description:Engrams are considered to be substrates for memory storage, and the functional dysregulation of the engrams leads to cognition impairment.However, the cellular basis for these maladaptive changes lead to the forgetting of memories remains unclear. Here we found that the expression of autophagy protein 7 (Atg7) mRNA was dramatically upregulated in aged DG engrams, and led to the forgetting of contextual fear memory and the activation of surrounding microglia.To determine mechanism by which autophagy in DG engrams activates the surrounding microglia, mice were co-injected AAV-RAM-Cre either with AAV-Dio-Atg7-Flag or AAV-Dio- EYFP in dorsal dentate gyrus to overexpress ATG7 in the DG memory engrams. Microglia were separated using magnetic-activated cell sorting and subjected to RNA-Seq in dorsal hippocampus .Bioinformatics analysis shown overexpression of Atg7 in dorsal DG memory engrams caused an increase in the expression of Tlr2 in the surrounding microglia.Depletion of Toll-like receptor 2/4 (TLR2/4) in DG microglia prohibited excessive microglial activation and synapse elimination induced by the overexpression of ATG7 in DG engrams, and thus prevented forgetting. Furthermore, the expression of Rac1, a Rho-GTPases which regulates active forgetting in both fly and mice, was upregulated in aged engrams. Optogentic activation of Rac1 in DG engrams promoted the autophagy of the engrams, the activation of microglia, and the forgetting of fear memory. Invention of the Atg7 expression and microglia activation attenuated forgetting induced by activation of Rac1 in DG engrams. Together, our findings revealed autophagy-dependent synapse elimination of DG engrams by microglia as a novel forgetting mechanism.
Project description:BackgroundCopy number variation is an important dimension of genetic diversity and has implications in development and disease. As an important model organism, the mouse is a prime candidate for copy number variant (CNV) characterization, but this has yet to be completed for a large sample size. Here we report CNV analysis of publicly available, high-density microarray data files for 351 mouse tail samples, including 290 mice that had not been characterized for CNVs previously.ResultsWe found 9634 putative autosomal CNVs across the samples affecting 6.87% of the mouse reference genome. We find significant differences in the degree of CNV uniqueness (single sample occurrence) and the nature of CNV-gene overlap between wild-caught mice and classical laboratory strains. CNV-gene overlap was associated with lipid metabolism, pheromone response and olfaction compared to immunity, carbohydrate metabolism and amino-acid metabolism for wild-caught mice and classical laboratory strains, respectively. Using two subspecies of wild-caught Mus musculus, we identified putative CNVs unique to those subspecies and show this diversity is better captured by wild-derived laboratory strains than by the classical laboratory strains. A total of 9 genic copy number variable regions (CNVRs) were selected for experimental confirmation by droplet digital PCR (ddPCR).ConclusionThe analysis we present is a comprehensive, genome-wide analysis of CNVs in Mus musculus, which increases the number of known variants in the species and will accelerate the identification of novel variants in future studies.