Project description:Purpose:RNA-Seq analysis was performed on mouse hearts with or without hispidulin treatment 4 weeks after arotic banding or sham surgery to determining the effect of hispidulin on pressure overload induced cardiac hypertrophy. Methods: the mRNA profiles of mouse hearts underwent sham or arotic banding surgery with treatment of hispidulin or DMSO were generated by RNA-seq analysis in triplicate. The expression level of gene was calculated by RSEM(v.1.2.12). Differential expression analysis was performed using the DESeq2(V 1.4.5). Results: RNA isolation, library construction, and sequencing were performed on a BGISEQ-500 (Beijing Genomic Institution, www.genomics.org.cn, BGI). For the gene expression analysis, the fold changes were also estimated according to the fragments per kilobase of exon per million fragments mapped (FPKM) in each sample. The significance of different gene expression was defined by the following filter criteria: false discovery rate (FDR) ≤0.001 and log2-ratio 1. After comparing of DMSO+AB group and hispidulin+AB group, we found that 113 genes were significantly differentially expressed. Gene ontology and cluster analysis indicated that alternated genes were enriched in fatty acid oxidation, glucose metabolism, TCA cycle, oxidative phosphorylation, hypertrophic cardiomyopathy, ECM organism, oxidative stress and unfolded protein binding. This result indicated that hispidulin improved mitochondrial function. Conclusions: Our study represents the first detailed analysis of heart transcriptomes, with biologic replicates, generated by RNA-seq technology. The optimized data analysis workflows reported here should provide a framework for comparative investigations of expression profiles. Our results show that NGS offers a comprehensive and more accurate quantitative and qualitative evaluation of mRNA content within a cell or tissue. We conclude that RNA-seq based transcriptome characterization would expedite genetic network analyses and permit the dissection of complex biologic functions.
Project description:Hypertrophic cardiomyopathy (HCM) is one of the most frequent inherited heart condition and a well-established risk factor for cardiovascular mortality worldwide. Although hypertrophy is traditionally regarded as an adaptive response to increased workload caused by physiological or pathological stress, prolonged hypertrophy can lead to heart failure characterized by impaired systolic function, increased apoptosis, fibrosis, ventricular dilation, and impaired metabolic substrate flexibility. While the key regulators for cardiac hypertrophy are well studied, the role of Prdm16 in this process remains poorly understood. In the present study, we demonstrate that Prdm16 is dispensable for cardiac development. However, it is required in the adult heart to preserve mitochondrial function and inhibit hypertrophy with advanced age. Cardiac-specific deletion of Prdm16 results in cardiac hypertrophy, excessive ventricular fibrosis, mitochondrial dysfunction, and impaired metabolic flexibility, leading to heart failure. We demonstrate that Prdm16 and euchromatic histone-lysine N- methyltransferase factors (Ehmts) act together to reduce the expression of fetal genes reactivated in pathological hypertrophy by inhibiting the functions of pro- hypertrophic transcription factor Myc. Although young Prdm16 knockout mice show normal cardiac function, they are predisposed to develop heart failure in response to metabolic stress. Collectively, our results demonstrate that Prdm16 protects the heart against age-dependent cardiac hypertrophy, fibrosis, mitochondrial dysfunction, adverse metabolic remodeling, and heart failure.
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
Project description:Pathological cardiac hypertrophy is a major risk factor for the development of heart failure and sudden cardiac death, yet the molecular mechanism of cardiac hypertrophy is not fully understood. Recently, we found that the expression of Lin28a, a RNA-binding protein, was significantly upregulated during the early stages of cardiac hypertrophy. Interestingly, cardiac specific conditional deletion of Lin28a blunted pressure overload-induced cardiac hypertrophic responses. Given that Lin28a can bind to diverse mRNA to regulate their abundance and/or translation, we conducted RNA-seq to profile the cardiac transcriptome alteration without Lin28a under pressure overload. It showed that metabolic pathways, including glycolysis and biosynthetic pathway, were remarkedly affected. Thus, our study identifies Lin28a as a crucial regulator of cardiac hypertrophy via its role in metabolic programming.
Project description:Background: Cardiac Ryanodine receptors (RyR2) can regulate Ca2+ release in the excitation-contraction coupling, when activated, it releases a large amount of Ca2+ into the cytoplasm. Additionally, studies have shown that dantrolene (a RyR2 inhibitor) protects against heart failure and arrhythmias by inhibiting domain decompression, Ca2+ leakage and diastolic Ca2+ sparking. However, the role and mechanism of dantrolene in cardiac hypertrophy remain unclear. Objective: In this study, we aimed to evaluate the therapeutic effects of dantrolene on pressure overload-induced cardiac hypertrophy in mice models by transverse aortic contraction (TAC) surgery and to explore its potential mechanism. Methods: C57/B6 mice (age: 8 weeks) underwent TAC or sham surgical procedure and were administered oral dantrolene (30 mg/kg) or the solvent drug postoperatively. After 4 weeks of drug treatment, RNA sequencing of mice left ventricle was performed.qRT–PCR validation was performed using SYBR Green assays. Results: We found that dantrolene significantly alleviated TAC-induced cardiac hypertrophy. According to RNA sequencing, 184 down-regulated genes were found after dantrolene treatment compared with TAC group, 8 of these were validated with qRT–PCR. According to the KEGG analysis, Creb3l3, IL18R1 and Ccl5 were down-regulated after dantrolene treatment, which were related to TNF-α pathway. Conclusion: As a RyR2 inhibitor, dantrolene attenuates cardiac hypetrophy through downregulating the TNF-α/NF-κB/NLRP3 signaling pathway.