Sarcomeric Regulation of Signal Transduction and Cardiomyopathy

项目摘要/摘要 肌节是心肌细胞(CMS)中产生驱动力的特殊细胞骨架结构 心脏收缩。编码肌节成分的基因突变，或“肌节突变”，通常 导致遗传性心肌病，包括大多数遗传性扩张型心肌病(DCM)。肌节 突变被认为会削弱CM的收缩，从而导致DCM心脏的收缩缺陷。怎么- 肌节功能的其他方面是否与扩张型心肌病的发病机制有关尚不完全清楚。 学习。这种知识差距阻碍了对扩张型心肌病发病机制的全面了解，并限制了对 制定有效的治疗策略。 这项研究方案测试了肌节调节信号转导的最重要的假设， 这在扩张型心肌病的发病机制中起重要作用。具体地说，郭博士将剖析Ac-Ac-Ac的作用机制。 TiNiN-2(ACTN2)突变通过SRF辅因子MKL1/2干扰血清反应因子(SRF)信号转导，以及 这条通路对扩张型心肌病的贡献。这一假设将通过三个具体目标进行检验。目标1将 研究ACTN2是否通过促进CMS中的肌动蛋白聚合来激活MKL-SRF信号。AIM 2将去- 终止If，那么ACTN2-MKL1/2通路通过影响SRF-染色质结合来调节CMS的转录。 目的3将验证ACTN2-MKL-SRF信号与扩张型心肌病发病机制有关的假设 由ACTN2错义突变引起。该项目将揭示扩张型心肌病发病机制的新分子见解。 这些见解可能会导致治疗扩张型心肌病的新的治疗方法。 该项目建立在最先进的技术基础上，如腺相关病毒(AAV)递送 基于CRISPR/Cas9的体细胞突变和心脏遗传马赛克分析 郭医生。K99/R00将进一步赞助诱导多能干细胞(HiPSCs)培训、基因组编辑、SIN- 单细胞转录学和工程心脏组织，再加上郭博士过去的专业知识，将建立- LISH为成功的独立研究提供了一个强大而全面的技术平台。这笔赠款还将 支持郭博士的教育，由具有相关专业知识和设施的世界级科学家组成的导师团队- 在郭博士向独立过渡之际，他谈到了他的职业发展活动。

PROJECT SUMMARY/ABSTRACT Sarcomeres are specialized cytoskeletal structures in cardiomyocytes (CMs) that generate the force driving the heart contraction. Mutations in genes coding sarcomere components, or “sarcomere mutations”, often cause inherited cardiomyopathies including most cases of inherited dilated cardiomyopathy (DCM). Sarcomere mutations are believed to impair CM contraction, thereby causing the contractile defects in DCM hearts. How- ever, whether other aspects of sarcomere function contribute to DCM pathogenesis has been incompletely studied. This knowledge gap prevents comprehensive understanding of DCM pathogenesis and limits the de- velopment of effective therapeutic strategies. This research proposal tests the overarching hypothesis that sarcomeres regulate signal transduction, which contributes to the pathogenesis of DCM. Specifically, Dr. Guo will dissect the mechanisms by which ac- tinin-2 (ACTN2) mutations perturb serum response factor (SRF) signaling through SRF cofactors MKL1/2, and the contribution of this pathway to DCM. This hypothesis will be tested through three Specific Aims. Aim 1 will study whether ACTN2 activates MKL-SRF signaling by promoting actin polymerization in CMs. Aim 2 will de- termine if then ACTN2-MKL1/2 pathway regulates transcription in CMs by affecting SRF-chromatin binding. Aim 3 will test the hypothesis that ACTN2-MKL-SRF signaling contributes to the pathogenesis of DCM caused by ACTN2 missense mutations. This project will reveal novel molecular insights about DCM pathogenesis. These insights may lead to new therapeutic approaches to treat DCM. This project is built upon state-of-the-art technologies such as adeno-associated virus (AAV)-delivered CRISPR/Cas9-based somatic mutagenesis and cardiac genetic mosaics analysis that were co-developed by Dr. Guo. K99/R00 will further sponsor training in induced pluripotent stem cells (hiPSCs), genome editing, sin- gle-cell transcriptomics and engineered heart tissues, which together with Dr. Guo’s past expertise will estab- lish a powerful and comprehensive technical platform for successful independent research. This grant will also support Dr. Guo’s education from a mentorship team of world-class scientists with relevant expertise and facili- tate Dr. Guo’s career development activities as he transitions toward independence.