Piezo1介导机械应力调控心肌肥厚心室重塑的作用及机制

Recent studies indicated that mechanical stress plays an important role in myocardial hypertrophy and ventricular remodeling, and mechanical stress activated ion channels plays an important role. Piezo1, a newly discovered ion channel activated by stress, is involved in vascular remodeling. However, its role in myocardial hypertrophy and ventricular remodeling has not been reported. We detected Piezo1 protein expression in cultured neonatal cardiomyocyte of mice. Moreover, increased Piezo1 expression accompanied with elevated mechanical stress is closely related with progression of myocardial hypertrophy in mouse trans-aorta coarctation (TAC) model. We therefore hypothesized that Piezo1 mediates mechanical stress-induced cardiac hypertrophy and ventricular remodeling, possibly via promoting intracelluar calcium reflux to activate calcineurin/NFATc1 pathyway, activating PI3K/Akt/mTOR pathway, and finally results to myocardial hypertrophy. In our study, we would employ the technology of Crispr/Cas9 to construct cardiomyocytes conditional Piezo1 knockout mice, and Piezo1 shRNA to knockdown Piezo1 or overexpressiong of Piezo1 in mice myocardiocytes, to explore the effects and underlying mechanisms of Piezo1 in mechanical stress-induced myocardial hypertrophy and ventricular remodeling in TAC and cardiomyocytes Felx cell stretch model.

近来发现机械应力在心肌肥厚心室重塑中起着重要的作用，应力激活离子通道是其重要的信号途径。Piezo1是新发现的应力激活离子通道，参与机械应力介导的血管重塑，但其对心室重塑的作用未见报道。我们发现培养的小鼠心肌细胞高表达Piezo1；小鼠主动脉弓缩窄心肌肥厚模型中，随着机械应力增加和心肌肥厚的进行性加重，Piezo1表达显著增加。因此，推测Piezo1介导机械应力调控心肌肥厚心室重塑的进程。Piezo1可能通过增加钙内流，激活CaN/NFATc1；Piezo1也可能激活PI3K/Akt/mTOR促心肌肥厚通路。本研究拟应用Crispr/Cas9心肌细胞条件性Piezo1敲除小鼠和Piezo1 shRNA技术使心肌细胞敲除或过表达Piezo1，在主动脉弓缩窄心肌肥厚模型和小鼠心肌细胞Flex cell牵张模型中，将首次揭示Piezo1介导机械应力调控心肌肥厚心室重塑中的作用及机制。

Piezo1是应力激活的离子通道，参与机械应力介导的血管重塑，但在心室重塑中的作用及机制尚无报道。本项目旨在阐明Piezo1在压力诱导的心肌肥厚中的作用和机制。应用小鼠主动脉弓缩窄致心肌肥厚模型，发现Piezo1表达随着机械应力增加和心肌肥厚加重而升高，并主要定位于心肌细胞。因此，构建心肌细胞条件性Piezo1敲除小鼠，证实心肌细胞Piezo1敲除显著抑制压力诱导的心肌肥厚，延缓心室重塑和心力衰竭进展。同时，应用培养的新生鼠心肌细胞去氧肾上腺素刺激心肌细胞肥大模型，发现Piezo1特异性激动剂Yoda1可促进心肌细胞肥大，而silence RNA技术抑制Piezo1表达能显著减轻心肌细胞的肥大，阐明了Piezo1具有促进心肌肥厚的作用。进一步通过转录组测序筛选、在体外新生鼠心肌细胞中Piezo1小分子抑制剂及相关通路抑制剂的验证，证实Piezo1通过激活钙调相关信号Calpain/CaN通路调控心肌肥厚的机制。研究结果首次揭示了Piezo1介导机械应力调控心肌肥厚心室重塑的作用及机制。