Project description:Numerous studies found intestinal microbiota alterations which are thought to affect the development of various diseases through the production of gut-derived metabolites. However, the specific metabolites and their pathophysiological contribution to cardiac hypertrophy or heart failure progression still remain unclear. N,N,N-trimethyl-5-aminovaleric acid (TMAVA), derived from trimethyllysine through the gut microbiota, was elevated with gradually increased risk of cardiac mortality and transplantation in a prospective heart failure cohort (n=1647). TMAVA treatment aggravated cardiac hypertrophy and dysfunction in high-fat diet-fed mice. Decreased fatty acid oxidation (FAO) is a hallmark of metabolic reprogramming in the diseased heart and contributes to impaired myocardial energetics and contractile dysfunction. Proteomics uncovered that TMAVA disturbed cardiac energy metabolism, leading to inhibition of FAO and myocardial lipid accumulation. TMAVA treatment altered mitochondrial ultrastructure, respiration and FAO and inhibited carnitine metabolism. Mice with γ-butyrobetaine hydroxylase (BBOX) deficiency displayed a similar cardiac hypertrophy phenotype, indicating that TMAVA functions through BBOX. Finally, exogenous carnitine supplementation reversed TMAVA induced cardiac hypertrophy. These data suggest that the gut microbiota-derived TMAVA is a key determinant for the development of cardiac hypertrophy through inhibition of carnitine synthesis and subsequent FAO.
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: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:Heart failure is driven by the interplay between master regulatory transcription factors and dynamic alterations in chromatin structure. Coordinate activation of developmental, inflammatory, fibrotic and growth regulators underlies the hallmark phenotypes of pathologic cardiac hypertrophy and contractile failure. While transactivation in this context is known to be associated with recruitment of histone acetyl-transferase enzymes and local chromatin hyperacetylation, the role of epigenetic reader proteins in cardiac biology is unknown. We therefore undertook a first study of acetyl-lysine reader proteins, or bromodomains, in heart failure. Using a chemical genetic approach, we establish a central role for BET-family bromodomain proteins in gene control during the evolution of heart failure. BET inhibition suppresses cardiomyocyte hypertrophy in a cell-autonomous manner, confirmed by RNA interference in vitro. Following both pressure overload and neurohormonal stimulation, BET inhibition potently attenuates pathologic cardiac remodeling in vivo. Integrative transcriptional and epigenomic analyses reveal that BET proteins function mechanistically as pause-release factors critical to activation of canonical master regulators and effectors that are central to heart failure pathogenesis. Specifically, BET bromodomain inhibition in mice abrogates pathology-associated pause release and transcriptional elongation, thereby preventing activation of cardiac transcriptional pathways relevant to the gene expression profile of failing human hearts. This study implicates epigenetic readers in cardiac biology and identifies BET co-activator proteins as therapeutic targets in heart failure. ChIP-Seq of mouse heart tissues from mice induced with heart failure and treated with JQ1 BET bromodomain inhibitor
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.