Project description:Overall goal: To elucidate fibroblast-specific role of TGFβ-Smad2/3 signaling in fibroblast activation and their differentiation to myofibroblasts. Purpose of analysis: To generate transcriptional profile of Smad2/3 and TGFβreceptors1/2-deficient fibroblasts in the context of pathological cardiac fibrosis.
Project description:Myocardial fibrosis is the most common pathological feather of adverse ventricular remodeling, and persistent fibrotic extension decreases myocardial compliance, promotes the development of heart failure. Epigenetics has been considered to play a potent regulatory role in the development of excessive myocardial fibrosis. Although, the explicit mechanism of epigenetic regulation in myocardial fibrosis still needs to be fully elucidated.RNA-seq analysis was used to screen differentially expressed genes in cardiac fibroblasts isolated from KDM5B KO and littermate control WT mice hearts at day 7 after MI operation.
Project description:Kinase-catalyzed phosphorylation plays crucial roles in numerous biological processes. CDC-like kinases (CLKs) are a group of evolutionarily conserved dual-specificity kinases that have been implicated in RNA splicing, glucose metabolism, diet-induced thermogenesis and so on. However, it is still largely unknown whether CLKs are involved in pathologic cardiac hypertrophy. This study aimed to investigate the role of CLKs in pathologic cardiac hypertrophy and the underlying mechanisms. Using small RNA interference, we discovered that defects in CLK4, but not CLK1, CLK2 or CLK3, were associated with the pathogenesis of pathological cardiomyocyte hypertrophy, while overexpression of CLK4 exerted resistance to isoproterenol-induced pathological cardiomyocyte hypertrophy. Moreover, the expression of CLK4 was significantly reduced in the failed myocardia of mice subjected to either transverse aortic constriction or isoproterenol infusion. Through the Cre/loxP system, we constructed cardiac-specific Clk4-knockout (Clk4-cKO) mice, which manifested pathological myocardial hypertrophy with progressive left ventricular systolic dysfunction and heart dilation. Phosphoproteomic analysis revealed significant changes in phosphorylation of sarcomere-related proteins in Clk4-cKO mice. Further experiments identified nexilin (NEXN), an F-actin binding protein, as the direct substrate of CLK4, and overexpression of a phosphorylation-mimic mutant of NEXN was sufficient to reverse the hypertrophic growth of cardiomyocytes induced by Clk4 knockdown. Importantly, restoring the phosphorylated NEXN significantly ameliorated the myocardial hypertrophy in Clk4-cKO mice. CLK4 phosphorylates NEXN to regulate the development of pathological cardiac hypertrophy. CLK4 may serve as a potential intervention target for the prevention and treatment of heart failure.
Project description:Deubiquitinating enzymes have gained more and more attention in the field of pathological cardiac hypertrophy. In this study, we explored the role of a deubiquitinase, OTUD1, in the transverse aortic constriction (TAC) induced cardiac hypertrophy. We found the upregulation of OTUD1 in heart tissues of TAC mice. OTUD1 overexpression promoted cardiac hypertrophy, cardiac fibrosis and apoptosis. Conversely, OTUD1 depletion alleviated these pathological changes both in vivo and in vitro. Mechanistically, ASK1 was identified as one substrate of OTUD1 using co-immunoprecipitation followed with LC-MS/MS. Interestingly, OTUD1 didn’t deubiquitinate ASK1, but increased the phosphorylation level of ASK1 during the process of cardiac hypertrophy. We found that PGAM5, the upper stream regulator of ASK1, was stabilized by OTUD1 in a K63 ubiquitin chain dependent way, which reminded us OTUD1 increased the phosphorylation level of ASK1 by deubiquitinating PGAM5. This study identified the OTUD1-ASK1 axis as a potential therapeutic target for pathological cardiac hypertrophy.
Project description:The heart undergoes physiological hypertrophy during pregnancy in healthy individuals. Metabolic syndrome (MetS) is now prevalent in women of child-bearing age and might add risks of adverse cardiovascular events during pregnancy. The present study asks if cardiac remodeling during pregnancy in obese individuals with MetS is abnormal and whether this predisposes them to a higher risk for cardiovascular disorders. The idea that MetS induces pathological cardiac remodeling during pregnancy was studied in a long-term (15 weeks) Western diet–feeding animal model that recapitulated features of human MetS. Pregnant female mice with Western diet (45% kcal fat)–induced MetS were compared with pregnant and nonpregnant females fed a control diet (10% kcal fat). Pregnant mice fed a Western diet had increased heart mass and exhibited key features of pathological hypertrophy, including fibrosis and upregulation of fetal genes associated with pathological hypertrophy. Hearts from pregnant animals with WD-induced MetS had a distinct gene expression profile that could underlie their pathological remodeling. Concurrently, pregnant female mice with MetS showed more severe cardiac hypertrophy and exacerbated cardiac dysfunction when challenged with angiotensin II/phenylephrine infusion after delivery. These results suggest that preexisting MetS could disrupt physiological hypertrophy during pregnancy to produce pathological cardiac remodeling that could predispose the heart to chronic disorders.
Project description:Cardiac hypertrophy can lead to heart failure, and is induced either by physiological stimuli eg postnatal development, chronic exercise training or pathological stimuli eg pressure or volume overload. Majority of new therapies for heart failure has mixed outcomes. A combined mouse model and oligo-array approach are used to examine whether phosphoinositide 3-kinase (p110-alpha isoform) activity is critical for maintenance of cardiac function and long-term survival in a setting of heart failure. The significance and expected outcome are to recognise genes involved in models of heart failure ie pathological- vs physiology-hypertrophy, and examine the molecular mechanisms responsible for such activity. Growth of the heart can be induced by physiological stimuli e.g., postnatal development, chronic exercise training, or pathological stimuli e.g., pressure or volume overload. Physiological hypertrophy (“good”) is characterised by a normal organisation of cardiac structure, and normal or enhanced cardiac function. In comparison, pathological hypertrophy (”bad”) is associated with fibrosis, cardiac dysfunction, and increased morbidity and mortality. The mechanistic process which allows the heart to enlarge in response to physiological stimuli while maintaining normal or enhanced function is of great clinical relevance because one potential therapeutic strategy is to inhibit the pathological growth process while augmenting the physiological growth process. One of the major process that regulate heart size is by phosphoinositide 3-kinase (PI3K). Thus the end goal of this project is to determine whether the p110 alpha isoform of PI3K could be a potential tool for augmenting physiological growth and improving cardiac function of the failing diseased heart, and to examine the underlying mechanisms responsible. Keywords: Disease progression analysis