Project description:Cartilage originates from mesenchymal cell condensations that differentiate into chondrocytes of transient growth plate cartilage or permanent cartilage of the articular joint surface and trachea. MicroRNAs fine-tune the activation of entire signaling networks and thereby modulate complex cellular responses, but so far only limited data are available on miRNAs that regulate cartilage development. Here we characterize an miRNA which promotes the biosynthesis of a key component in the RAF/MEK/ERK pathway in cartilage. Specifically, by transcriptome profiling we identified miR-322 to be upregulated during chondrocyte differentiation. Among the various miR-322 target genes in the RAF/MEK/ERK pathway, only Mek1 was identified as a regulated target in chondrocytes. Surprisingly, an increased concentration of miR-322 stabilizes Mek1-mRNA to arise protein levels and dampen ERK1/2 phosphorylation, while cartilage-specific inactivation in mice linked the loss of miR-322 to decreased MEK1 levels and increased RAF/MEK/ERK pathway activation. Such mice died perinatally due to tracheal growth restriction and respiratory failure. Hence, a single miRNA can stimulate the production of an inhibitory component of a central signaling pathway to impair cartilage development.
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:The aim of the study was to investigate whether the trefoil peptide genes, in concerted action with a miRNA regulatory network, were contributing to nutritional maintrenance. Using a Tff2 knock-out mouse model, 48 specific miRNAs were noted to be significantly deregulated when compared to the wild type strain.
Project description:The aim of the study was to investigate whether the trefoil peptide genes, in concerted action with a miRNA regulatory network, were contributing to nutritional maintrenance. Using a Tff3 knock-out mouse model, 21 specific miRNAs were noted to be significantly deregulated when compared to the wild type strain.
Project description:Articular and growth plate cartilage have comparable structures consisting of three distinct layers of chondrocytes, suggesting similar differentiation programs and therefore similar gene expression profiles. To address this hypothesis and to explore transcriptional changes that occur during the onset of articular and growth plate cartilage divergence, we used microdissection of 10-day-old rat proximal tibial epiphyses, microarray analysis, and bioinformatics to compare gene expression profiles in individual layers of articular and growth plate cartilage. We found that many genes that were spatially upregulated in intermediate/deep zone of articular cartilage were also spatially upregulated in resting zone of growth plate cartilage (overlap greater than expected by chance, P < 0.001). Interestingly, superficial zone of articular cartilage showed an expression profile with similarities to both proliferative and hypertrophic zones of growth plate cartilage (P < 0.001 each). Additionally, significant numbers of known proliferative zone markers (3 out of 6) and hypertrophic zone markers (27 out of 126) were spatially upregulated in superficial zone compared to intermediate/deep zone (more than expected by chance, P < 0.001 each). In conclusion, we provide evidence that intermediate/deep zone of articular cartilage has a gene expression profile more similar to resting zone of growth plate cartilage, whereas superficial zone has a gene expression profile more similar to proliferative and hypertrophic zones.
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: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:The aim of the current study was to identify molecular markers for articular cartilage that can be used for the quality control of tissue engineered cartilage. Therefore a genom-wide expression analysis was performed using RNA isolated from articular and growth plate cartilage, both extracted from the knee joints of minipigs. Keywords: Native material or primary cells isolated from articular cartilage and growth plate cartilage
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.