Project description:During acute sympathetic stress, the overeactivation of β-adrenergic receptors (β-ARs) caused cardiac fibrosis, by triggering inflammation and cytokine expression. It is unknown whether exercise training inhibited acute β-AR overactivation-induced cytokine expression and cardiac injury. Here, we reported that running exercise inhibited cardiac fibrosis and improved cardiac function in mice treated by isoproterenol, a β-AR agonist. Cytokine antibody array revealed that exercise prevented the expression changes of most cytokines induced by isoproterenol. Specifically, 18 ISO-upregulated and 3 ISO-downregulated cytokines belonged to six families (eg. chemokine) were prevented. A further KEGG analysis of these cytokines revealed that Hedgehog and Rap1 signaling pathways were involved in the regulation of cytokine expression by exercise. The expression changes of some cytokines that were prevented by exercise were verified by ELISA and real-time PCR. In conclusion, running exercise prevented the cytokine changes following acute β-AR overactivation and therefore attenuated cardiac fibrosis.
Project description:Physiological exercise leads to an activation of an distinct genetic program in the heart. During this process, we identified histone deacetlyase 4 (HDAC4) as an epigentic modifier, that regulates this adaptive process. To identify HDAC4 dependent genes that can are regulated after physiological stress, we investigated the cardiac gene expression in cardiomyocyte specific HDAC4 knockout animals and control animals after running exercise. We used microarrays to detail the global programme of gene expression underlying physiological cardiac adaption on exercise and identified distinct, histone deacetylase 4 dependent up-regulated genes during this process.
Project description:Comparative analysis of mouse cardiac left ventricle gene expression: voluntary wheel exercise and pregnancy-induced cardiac hypertrophy We performed microarray analysis on RNA from left ventricles of mice in non-pregnant diestrus cycle, mid-pregnancy (MP), late-pregnancy (LP), and immediate post-partum (0PP). These were compared to 7days (7EX) and 21 days (21EX) of voluntary wheel running exercise.
Project description:Calorie restriction (CR) improved healthspan in two longitudinal studies in nonhuman primates (NHPs), yet only the University of Wisconsin (UW) study demonstrated an increase in survival in CR monkeys relative to controls; the National Institute on Aging (NIA) study did not. Here, analysis of left ventricle samples showed that CR did not reduce cardiac fibrosis relative to controls. However, there was a 5.9-fold increase of total fibrosis in UW hearts, compared to NIA. Diet composition was a prominent difference between the studies; therefore, we used the NHP diets to characterize diet-associated molecular and functional changes in the hearts of mice. Consistent with the findings from the NHP samples, mice fed UW or a modified NIA diet with increased sucrose and fat developed greater cardiac fibrosis compared to the NIA diet, and transcriptomics analysis revealed diet-induced activation of myocardial oxidative phosphorylation and cardiac muscle contraction pathways.
Project description:Deletion of Tmem43 encoding nuclear membrane protein TMEM43, specifically in mouse cardiac myocytes leads to cardiac fibrosis and dysfunction. Temporal RNA-seq identified early and late trascriptomic changes and implicates TGFb1 in the pathogenesis of ACM caused by Tmem43 haploinsufficiency.
Project description:Fibrotic changes in the myocardium and cardiac arrhythmias represent fatal complications in rheumatic disease systemic sclerosis (SSc), however the underlying mechanisms remain elusive. Fos-related antigen-2 (Fosl-2) has been implicated in development of organ fibrosis. Mice overexpressing Fosl-2 (Fosl-2tg) showed interstitial cardiac fibrosis, disorganized connexin43/40 in intercalated discs and deregulated expression of genes controlling conduction system. Fosl-2tg mice developed higher heart rate (HR), prolonged QT intervals, arrhythmias with prevalence of premature ventricular contractions, ventricular tachycardias, II-degree atrio-ventricular blocks and reduced HR variability. Following stimulation with isoproterenol Fosl-2tg mice showed impaired HR response. To assess the role of inflammation in cardiac fibrosis we used Rag2-/-Fosl-2tg mice lacking T/B cells. These mice showed no myocardial fibrosis and ECG abnormalities. Transcriptomics analysis of cardiac Rag-2-/-Fosl-2wt/Rag2-/-Fosl-2tg/Fosl-2tg fibroblasts revealed that systemic inflammation triggered fibrotic and arrhythmogenic alterations while Fosl-2-overexpression mediated profibrotic signature. In human cardiac fibroblasts FOSL-2-overexpression enhanced myofibroblast signature under proinflammatory or profibrotic stimuli. These results demonstrate that under immunofibrotic conditions activator protein 1 transcription factor component Fosl-2 exaggerates myocardial fibrosis, arrhythmias and aberrant response to stress.