Project description:Cardiac metabolism is deranged in heart failure, but underlying mechanisms remain unclear. Lysine demethylase 8 (Kdm8) represses gene expression in the embryo and controls metabolism in cancer. However, its function in cardiac homeostasis is unknown. We show that Kdm8 maintains a mitochondrial gene network active by repressing Tbx15 to prevent dilated cardiomyopathy leading to lethal heart failure. Deletion of Kdm8 in mouse cardiomyocytes increased H3K36me2 with activation of Tbx15 and repression of target genes in the NAD+ pathway before dilated cardiomyopathy initiates. Moreover, NAD+ supplementation prevented dilated cardiomyopathy in Kdm8 mutant mice and TBX15 overexpression blunted NAD+-activated cardiomyocyte respiration. Furthermore, KDM8 was downregulated in human hearts affected by dilated cardiomyopathy and higher TBX15 expression defines a subgroup of affected hearts with the strongest downregulation of genes encoding mitochondrial proteins. Thus, KDM8 represses TBX15 to maintain cardiac metabolism. Our results suggest that epigenetic dysregulation of metabolic gene networks initiates myocardium deterioration towards heart failure and could underlie heterogeneity of dilated cardiomyopathy.
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:Mice heterozygous for dn-p21 littermates were sacrificed at 10 weeks of age. Ventricles were isolated and snap-frozen in liquid nitrogen. Use 3 month old FVB Females as controls. [GSM2334, GSM2335, GSM2336] Read more at http://cardiogenomics.med.harvard.edu/groups/proj1/pages/ras_home.html Keywords = ras Keywords = dilated cardiomyopathy Keywords: other
Project description:Increased COUP-TFII levels are found in human dilated cardiomyopathy as well as in mouse models that develop cardiomyopathy. COUP-TFII overexpression in adult mouse hearts caused ventricular dilation and compromised cardiac functions. To gain insights on COUP-TFII’s effect in hearts, we identified the molecular profile of COUP-TFII overexpressing hearts through microarray analysis. The result may shred light on molecular mechanisms that mediate development of dilated cardiomyopathy.
Project description:Cardiac metabolism is deranged in heart failure, but underlying mechanisms remain unclear. Lysine demethylase 8 (Kdm8) represses gene expression in the embryo and controls metabolism in cancer. However, its function in cardiac homeostasis is unknown. We show that Kdm8 maintains a mitochondrial gene network active by repressing Tbx15 to prevent dilated cardiomyopathy leading to lethal heart failure. Deletion of Kdm8 in mouse cardiomyocytes increased H3K36me2 with activation of Tbx15 and repression of target genes in the NAD+ pathway before dilated cardiomyopathy initiates. Moreover, NAD+ supplementation prevented dilated cardiomyopathy in Kdm8 mutant mice and TBX15 overexpression blunted NAD+-activated cardiomyocyte respiration. Furthermore, KDM8 was downregulated in human hearts affected by dilated cardiomyopathy and higher TBX15 expression defines a subgroup of affected hearts with the strongest downregulation of genes encoding mitochondrial proteins. Thus, KDM8 represses TBX15 to maintain cardiac metabolism. Our results suggest that epigenetic dysregulation of metabolic gene networks initiates myocardium deterioration towards heart failure and could underlie heterogeneity of dilated cardiomyopathy.