Project description:There is evidence that microglia interact with infiltrating Th1 and Th17 cells and this interaction results in mutual activation. However, the potential of a distinct cytokine milieu generated by these effector T cell subsets to activate microglia is poorly understood. In this study, we tested the ability of factors secreted by Th1 and Th17 cells to induce microglial activation. Interestingly, we found that only Th1-associated factors had the potential to activate microglia while the Th17-associated factors as well as direct contact of Th17 cells with microglia only had a minimal effect. Further Th1-derived factors triggered a proinflammatory M1-type gene expression profile in microglia Microglia harvested from mixed glial cultures were treated with supernatants from Th1- or Th17 cultures. Microglia cultured in medium was used as controls. At 16h post treatment RNA was isolated from the microglia and probed on Agilent´s murine 4x44k microarrays. RNA isolated from four independent experiments were used for the gene expression profiling. Microglia, Th1, Th17
Project description:There is evidence that microglia interact with infiltrating Th1 and Th17 cells and this interaction results in mutual activation. However, the potential of a distinct cytokine milieu generated by these effector T cell subsets to activate microglia is poorly understood. In this study, we tested the ability of factors secreted by Th1 and Th17 cells to induce microglial activation. Interestingly, we found that only Th1-associated factors had the potential to activate microglia while the Th17-associated factors as well as direct contact of Th17 cells with microglia only had a minimal effect. Further Th1-derived factors triggered a proinflammatory M1-type gene expression profile in microglia
Project description:Autoreactive T cells that infiltrate into the central nervous system (CNS) are believed to have a significant role in mediating the pathology of neurodegenerative diseases such as Alzheimer's disease, amyotrophic lateral sclerosis and multiple sclerosis. Their interaction with microglia and astrocytes in the CNS is crucial for the regulation of the neuroinflammatory process. Our previous work demonstrated that effectors secreted by Th1 and Th17 cells have different capacities to influence the phenotype and function of the glial cells. We have shown that Th1 effectors altered the phenotype and function of both microglia and astrocytes whereas Th17 effectors induced direct effects only on astrocytes but not on microglia. Here we investigated if effector molecules associated with IFN-g producing Th1 cells induced different gene expression profiles in microglia and astrocytes. We performed a microarray analysis of RNA isolated from microglia and astrocytes treated with medium and Th1 culture supernatants and compared the gene expression data. By using the criteria of 2-fold change and a false discovery rate of 0.01 (corrected p-value < 0.01), we demonstrated that a total of 2106 and 1594 genes were differentially regulated microglia and astrocytes respectively in response to Th1-derived factors. We observed that Th1 associated effectors induce distinct transcriptional changes in microglia and astrocytes in addition to commonly regulated transcripts. These distinct transcriptional changes regulate distinct physiological functions and this knowledge can help in better understanding of T cell mediated neuropathologies.
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:CD4+ T cells differentiate into phenotypically distinct T-helper cells upon antigenic stimulation. Regulation of plasticity between these CD4+ T-cell lineages is critical for immune homeostasis and prevention of autoimmune diseases. However, the factors that regulate lineage stability are largely unknown. Here we investigate a role for retinoic acid (RA) in the regulation of lineage stability using T helper 1 (Th1) cells, traditionally considered the most phenotypically stable Th subset. We found that RA, through its receptor RARa, sustains stable expression of Th1 lineage specifying genes as well as repressing genes that instruct Th17 cell fate. RA signaling is essential for limiting Th1 cell conversion into Th17 effectors and for preventing pathogenic Th17 responses in vivo. Our studies identify RA-RARa as a key component of the regulatory network governing Th1 cell fate and define a new paradigm for the development of pathogenic Th17 cells. These findings have important implications for autoimmune diseases in which dysregulated Th1-Th17 responses are observed. Identification of RARa binding in wild-type Th1 cells and mapping of enhancers using chromatin IP against p300, H3k4me1, H3k4me3, and H3k27ac in wild-type and dnRara Th1 cells.
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:SILAC based protein correlation profiling using size exclusion of protein complexes derived from Mus musculus tissues (Heart, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
Project description:SILAC based protein correlation profiling using size exclusion of protein complexes derived from seven Mus musculus tissues (Heart, Brain, Liver, Lung, Kidney, Skeletal Muscle, Thymus)
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.