Influence of Stim1 on TRPC post-translational modulation and cardiac hypertrophy

描述(申请人提供)：典型瞬时受体电位(TRPC)通道与钙调神经磷酸酶激活的T细胞核因子(CN-NFAT)信号介导的适应性不良心肌肥厚有关。然而，对渠道活动的监管还没有得到很好的理解。我们实验室已经报道了PKG磷酸化抑制TRPC6活性的一种调节机制。在HEK293细胞中的研究表明，TRPC通道的活性也可能受到基质相互作用蛋白-1(STIM1)的门控调节，STIM1最近被报道在体内参与了肥大反应。初步数据表明，STIM1和TRPC6通道偶联可能影响该通道的PKG抑制。这项拟议的工作有可能促进我们对心肌肥厚和随后的心力衰竭的分子机制的理解。通过更好地了解TRPC通道的调节，它在心脏病理的实验和模型中很重要，在人类心脏病中也上调，我们将了解治疗靶点的线索。我们假设STIM1与心肌细胞中的TRPC3和TRPC6通道相互作用，导致NFAT介导的钙内流增加和肥大信号转导。此外，我们认为心肌细胞中STIM1和TRPC3/6通道的偶联可以阻止PKG的磷酸化。我们将通过检测分离的心肌细胞的钙内流来测试这一点，并在体内探索STIM1和TRPC通道在啮齿动物心肌肥厚模型中的相互作用。

DESCRIPTION (provided by applicant): Canonical transient receptor potential (TRPC) channels are linked in maladaptive cardiac hypertrophy mediated by calcineurin-nuclear factor of activated T cells (Cn- NFAT) signaling. Yet, the regulation of channel activity is not well understood. Our lab has reported on one regulatory mechanism of by which PKG phosphorylation inhibits TRPC6 activity. Studies in HEK293 cells indicate TRPC channel activity may also be modulated by gating of stromal interacting protein-1 (Stim1) which was recently reported to contribute to the hypertrophic response in vivo. Preliminary data suggests that Stim1 and TRPC6 channel coupling may influence PKG inhibition of the channel. The proposed work has the potential to advance our understanding of the molecular mechanisms of cardiac hypertrophy and subsequent heart failure. By better understanding the modulation of TRPC channels, which are important in experimental and models of cardiac pathology and are also upregulated in human heart disease, we will learn clues about targets for therapy. We hypothesize that STIM1 interacts with TRPC3 and TRPC6 channels in the cardiomyocyte leading to increased calcium entry and hypertrophic signaling mediated by NFAT. Additionally, we propose that the coupling of Stim1 and TRPC3/6 channels in the cardiomyocyte prevents PKG phosphorylation. We will test this by examining the calcium influx in isolated cardiomyocytes, and in vivo we will explore the interaction between Stim1 and TRPC channels in rodent models of cardiac hypertrophy.