新型G蛋白偶联雌激素受体调控PKD参与心肌重塑的分子机制研究

Heart remodeling and failure is the leading cause of death in patients with cardiovascular diseases. Results from my last National Natural Science Foundation of China (NSFC)-funded project confirmed that protein kinase D (PKD) is involved in the development of pressure overload-induced cardiac hypertrophy, remodeling and heart failure through regulating cardiac autophagy. Our preliminary studies also found that a novel estrogen receptor, GPER, inhibited the activity of PKD by activating protein kinase A (PKA) in cultured cardiomyocytes. Considering that the incidence of heart diseases in women significantly increases after menopause, and that the estrogen replacement therapy in post-menopausal women did not show beneficial effects, the discovery of GPER has opened a new door in this field of research for developing more specific hormone therapy for postmenopausal women. This proposal will test our hypothesis that GPER protects heart from pressure-induced heart remodeling and failure by regulating PKA/PKD/autophagy pathways using genetic and pharmaceutic approaches in both in vivo and in vitro studies. Ovariectomized spontaneously hypertensive rat (SHR) and WKY rats, as well as cultured cardiomyocytes and cardiac fibroblasts will be used with the treatments of the agonists, antagonists, and siRNAs of GPER. Structure and functions, and the autophagy-related pathways will be evaluated in both the whole heart and the cell levels. PKA agonist and antagonist will be used to determine the involvement of PKA in mediating the protective effects of GPER. The functional roles of estrogen receptor (ER)α and ERβ will be also compared with GPER. The completion of this project will advance our understanding of how estrogen protects heart and provide experimental evidence for new therapeutic approach targeting GPER/PKD-mediated pathways.

心肌重塑和心力衰竭是心脏病患者死亡的主要原因之一。我们上一个国家自然科学基金项目证实蛋白激酶D（PKD）参与了自噬过程并减轻压力负荷所引起的心肌肥厚。我们的研究同时发现一种新的雌激素受体，GPER，可通过激活蛋白激酶A（PKA）而抑制PKD活性。基于绝经后女性心脏病发病率显著上升，而雌激素替代治疗效果不明确且可增加癌症发病率，GPER与绝经后女性心脏病发生关系的研究为近年来该领域的热点之一，以期更加明确绝经后女性心脏病的发生机制并研发更为特异性的激素替代治疗。因此，本项目拟通过在体动物实验以卵巢摘除的自发性高血压大鼠为模型，以及心肌细胞和成纤维细胞培养技术，借助于受体激活剂、拮抗剂及基因敲除技术，从细胞、组织以及整体水平深入而全面地探讨GPER通过PKA/PKD通路调控心肌自噬并对心肌损伤的保护机制。本项目的完成将为绝经后女性心血管疾病治疗的新靶点提供实验依据。

心肌肥厚和心力衰竭是心脏病患者死亡的主要原因之一，绝经后女性心脏肥大和心力衰竭的发生率显着增加。新型雌激素受体——G蛋白偶联受体是最近发现的雌激素受体，我们的研究发现其通过调控自噬水平发挥心肌保护作用，我们课题组最新的实验通过串联蛋白质谱分析筛选了新型G蛋白偶联受体下游作用的靶基因Rap1GAP。通过腺病毒及小干扰RNA过表达及敲除Rap1GAP，我们发现Rap1GAP通过调控氧化应激、自噬及凋亡参与心肌肥厚的发生及发展，为心肌肥厚的治疗提供新的治疗靶点。