Project description:As a type of secreted membrane vesicle, exosomes are emerging as an important mode of cell-to-cell communication. The objective of this study was to compare the abundance of transcripts present in the parental B16F0 cell to transcripts present in exosomes isolated from B16F0 conditioned media. Identifying local mechanisms of immunosuppression is a key barrier for expanding the clinical benefit of cancer immunotherapy. While exosomes are emerging as a new mode of intercellular communication, their role in establishing a malignant tissue niche remains unclear. Similar to the sculpting of tumor antigens during oncogenesis, a related hypothesis is that proteins secreted by malignant cells are shaped by somatic evolution. To test this hypothesis, we characterized the biological influence of tumor-derived exosomes on immune cell function. In particular, we analyzed exosomes from three melanoma models: B16F0, a non-immunogenic model of malignant melanoma; Cloudman S91, a model of immunogenic melanoma; and Melan-A, an immortalized melanocyte cell line. Using electron microscopy, exosomes derived from all three cell lines were morphologically similar. The exosomes contained receptors derived from the parent cell as demonstrated by IL12RB2 expression on B16F0 exosomes and intact mRNAs. Furthermore, transcript profiling of B16F0 exosomes and cells suggested that exosomal mRNA is enriched for mRNAs that target immune-related pathways, including Ptpn11 that inhibited T cell proliferation and Dnmt3a that inhibited T cell production of IFN-gamma. Functionally, B16F0 exosomes dose-dependently suppressed cell proliferation and the expression of IL12RB2 in primary CD8+ T cells. In contrast, Cloudman S91 exosomes promoted T cell proliferation and Melan-A exosomes had a negligible effect on primary CD8+ T cells. Collectively, the results are consistent with somatic editing of exosomal payloads and suggest that exosomes establish a density-dependent field effect by altering the activity of immune cells that enter the tumor microenvironment.
Project description:As a type of secreted membrane vesicle, exosomes are emerging as an important mode of cell-to-cell communication. The objective of this study was to compare the abundance of mRNA and miRNA present in the parental B16F0 cell to mRNA and miRNA present in exosomes isolated from B16F0 conditioned media. Identifying local mechanisms of immunosuppression is a key barrier for expanding the clinical benefit of cancer immunotherapy. While exosomes are emerging as a new mode of intercellular communication, their role in establishing a malignant tissue niche remains unclear. Similar to the sculpting of tumor antigens during oncogenesis, a related hypothesis is that proteins secreted by malignant cells are shaped by somatic evolution. To test this hypothesis, we characterized the biological influence of tumor-derived exosomes on immune cell function.
Project description:While recent clinical studies demonstrate the promise of cancer immunotherapy, a barrier for broadening the clinical benefit is identifying how tumors locally suppress cytotoxic immunity. As an emerging mode of intercellular communication, exosomes secreted by malignant cells can deliver a complex payload of coding and non-coding RNA to cells within the tumor microenvironment. Here, we quantified the RNA payload within tumor-derived exosomes and the resulting dynamic transcriptomic response to cytotoxic T cells upon exosome delivery to better understand how tumor-derived exosomes can alter immune cell function. Exosomes derived from B16F0 melanoma cells were enriched for a subset of coding and non-coding RNAs that did not reflect the abundance in the parental cell. Upon exosome delivery, RNAseq revealed the dynamic changes in the transcriptome of CTLL2 cytotoxic T cells. In analyzing transiently co-expressed gene clusters, pathway enrichment suggested that the B16F0 exosomal payload altered mitochondrial respiration, which was confirmed independently, and upregulated genes associated with the Notch signaling pathway. Interestingly, exosomal miRNA appeared to have no systematic effect on downregulating target mRNA levels.
Project description:We collected whole genome testis expression data from hybrid zone mice. We integrated GWAS mapping of testis expression traits and low testis weight to gain insight into the genetic basis of hybrid male sterility.
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: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.