Project description:Sustained Akt activation induces cardiac hypertrophy (LVH), which may lead to heart failure. This study tested the hypothesis that Akt activation contributes to mitochondrial dysfunction in pathological LVH. Akt activation induced LVH and progressive repression of mitochondrial fatty acid oxidation (FAO) pathways. Preventing LVH by inhibiting mTOR failed to prevent the decline in mitochondrial function but glucose utilization was maintained. Akt activation represses expression of mitochondrial regulatory, FAO, and oxidative phosphorylation genes in vivo that correlate with the duration of Akt activation in part by reducing FOXO-mediated transcriptional activation of mitochondrial-targeted nuclear genes in concert with reduced signaling via PPARα/PGC-1α and other transcriptional regulators. In cultured myocytes Akt activation disrupted mitochondrial bioenergetics, which could be partially reversed by maintaining nuclear FOXO, but not by increasing PGC-1α. Thus, although short-term Akt activation may be cardioprotective during ischemia by reducing mitochondrial metabolism and increasing glycolysis, long-term Akt activation in the adult heart contributes to pathological LVH in part by reducing mitochondrial oxidative capacity. Three samples per group of 8-week-old wild-type or transgenic mice with cardiac-specific constitutive expression of an activated Akt (caAkt) in the heart at 8 weeks of age were used. Mice have been previously described in depth (Shioi T, McMullen JR, Kang PM, Douglas PS, Obata T, Franke TF, Cantley LC, Izumo S. 2002. Akt/protein kinase B promotes organ growth in transgenic mice. Mol. Cell. Biol. 22:2799-2809.). After hearts were removed total myocardial RNA was labeled and processed as described below for microarray analysis to detail the global changes in gene expression underlying development of heart failure in this mouse model.
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:Heart failure with preserved ejection fraction (HFpEF) is a prevalent health condition associated with high morbidity and mortality, but currently, there are few effective therapies. Our previous research showed that inhibiting histone deacetylase 6 (HDAC6) had a beneficial effect on a genetic cardiomyopathy model. The overlapping underlying mechanisms involving inflammation and metabolism between cardiomyopathy and HFpEF prompted us to explore the role of HDAC6 in HFpEF. The results showed that inhibiting HDAC6 with TYA-018 reversed preexisting cardiac hypertrophy and diastolic dysfunction, and improved lung congestion and exercise capacity in mouse models of HFpEF, including a newly developed model that combines moderate trans-aortic constriction and high-fat diet to mimic the systemic and cardiovascular features of human HFpEF. Moreover, mice with genetic Hdac6 deletion delayed the development of HFpEF and were resistant to the effects of TYA-018. The efficacy of TYA-018 was comparable to a SGLT2 inhibitor, and the combination showed increased effects. Mechanistically, TYA-018 restored expression of gene sets associated with hypertrophy, fibrosis, and mitochondrial energy production in heart tissue from HFpEF mice. TYA-018 also inhibited activation of human cardiac fibroblasts and increased mitochondrial respiratory capacity in induced pluripotent stem cell–derived cardiomyocytes. These findings support the direct role of HDAC6 on HFpEF pathophysiology in the heart and that inhibiting HDAC6 may be a promising approach to treating HFpEF.
Project description:Sustained Akt activation induces cardiac hypertrophy (LVH), which may lead to heart failure. This study tested the hypothesis that Akt activation contributes to mitochondrial dysfunction in pathological LVH. Akt activation induced LVH and progressive repression of mitochondrial fatty acid oxidation (FAO) pathways. Preventing LVH by inhibiting mTOR failed to prevent the decline in mitochondrial function but glucose utilization was maintained. Akt activation represses expression of mitochondrial regulatory, FAO, and oxidative phosphorylation genes in vivo that correlate with the duration of Akt activation in part by reducing FOXO-mediated transcriptional activation of mitochondrial-targeted nuclear genes in concert with reduced signaling via PPARα/PGC-1α and other transcriptional regulators. In cultured myocytes Akt activation disrupted mitochondrial bioenergetics, which could be partially reversed by maintaining nuclear FOXO, but not by increasing PGC-1α. Thus, although short-term Akt activation may be cardioprotective during ischemia by reducing mitochondrial metabolism and increasing glycolysis, long-term Akt activation in the adult heart contributes to pathological LVH in part by reducing mitochondrial oxidative capacity.
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:Heart failure with preserved ejection fraction (HFpEF) is a prevalent health condition associated with high morbidity and mortality, but currently, there are few effective therapies. Our previous research showed that inhibiting histone deacetylase 6 (HDAC6) had a beneficial effect on a genetic cardiomyopathy model. The overlapping underlying mechanisms involving inflammation and metabolism between cardiomyopathy and HFpEF prompted us to explore the role of HDAC6 in HFpEF. The results showed that inhibiting HDAC6 with TYA-018 reversed preexisting cardiac hypertrophy and diastolic dysfunction, and improved lung congestion and exercise capacity in mouse models of HFpEF, including a newly developed model that combines moderate trans-aortic constriction and high-fat diet to mimic the systemic and cardiovascular features of human HFpEF. Moreover, mice with genetic Hdac6 deletion delayed the development of HFpEF and were resistant to the effects of TYA-018. The efficacy of TYA-018 was comparable to a SGLT2 inhibitor, and the combination showed increased effects. Mechanistically, TYA-018 restored expression of gene sets associated with hypertrophy, fibrosis, and mitochondrial energy production in heart tissue from HFpEF mice. TYA-018 also inhibited activation of human cardiac fibroblasts and increased mitochondrial respiratory capacity in induced pluripotent stem cell–derived cardiomyocytes. These findings support the direct role of HDAC6 on HFpEF pathophysiology in the heart and that inhibiting HDAC6 may be a promising approach to treating HFpEF.
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.
Project description:BackgroundLong terminal repeat (LTR) retrotransposons make up a large fraction of the typical mammalian genome. They comprise about 8% of the human genome and approximately 10% of the mouse genome. On account of their abundance, LTR retrotransposons are believed to hold major significance for genome structure and function. Recent advances in genome sequencing of a variety of model organisms has provided an unprecedented opportunity to evaluate better the diversity of LTR retrotransposons resident in eukaryotic genomes.ResultsUsing a new data-mining program, LTR_STRUC, in conjunction with conventional techniques, we have mined the GenBank mouse (Mus musculus) database and the more complete Ensembl mouse dataset for LTR retrotransposons. We report here that the M. musculus genome contains at least 21 separate families of LTR retrotransposons; 13 of these families are described here for the first time.ConclusionsAll families of mouse LTR retrotransposons are members of the gypsy-like superfamily of retroviral-like elements. Several different families of unrelated non-autonomous elements were identified, suggesting that the evolution of non-autonomy may be a common event. High sequence similarity between several LTR retrotransposons identified in this study and those found in distantly-related species suggests that horizontal transfer has been a significant factor in the evolution of mouse LTR retrotransposons.