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: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:Epigenetic modifications, such as cytosine methylation and histone modification, have been shown involved in the pathology of ischemic brain injury. Recent works have implicated 5-hydroxymethylcytosine (5hmC), a DNA base derived from 5-methylcytosine (5mC) through the oxidation by Ten-Eleven Translocation (TET) enzymes, in DNA methylation-related plasticity. In this study we show that 5hmC abundance could be induced to increase by ischemia injury. Genome-wide profiling of 5hmC identified differentially hydroxymethylated regions (DhMRs) associated with ischemic injury and DhMRs were found enriched among the genes involved in cell junction, neuronal morphogenesis and neurodevelopment. These data together suggest that 5hmC modification could serve as a potential therapeutic target for the treatment of ischemic stroke. To determine the genome-wide 5hmC distribution in both ischemic injury (I/R) and control mice (C57BL/6), we employed a previously established chemical labeling and affinity purification method, coupled with high-throughput sequencing (Song et al, Nature Biotechnology, 2011). The ischemic or matched control brain tissues from three pairs of ischemic mice and control mice were used for the analyses.
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:We inflicted TBI to wildetype (wt) mice in order to establish whether the anti-inflammatory agent cyclophosphamide can be used therapeutically. Cyclophosphamide was found to regulate distinct inflammatory cells such as activated microglia separate from invading phagocytes and dendritic cells. Cyclophosphamide postinjury selectively reduces antigen-presenting dendritic cells. Findings show feasibility of drug development to interfere with brain inflammation.