Aging and estrogen-dependent HDAC2 regulation: implications in cardiac injury

项目摘要 随着年龄的增长和雌激素（E2）水平的下降，女性患心血管疾病（CVD）的风险增加 在绝经期，但绝经后激素替代疗法（HRT）的有益效果， 降低风险仍然存在争议。雌激素通过诱导其受体ERα介导其保护作用 与E2靶基因结合。表观遗传酶如组蛋白脱乙酰酶（HDAC）的失调是 与病理性衰老有关，I类HDAC 2作为心脏肥大的正调节因子发挥作用 (CH)来应对压力。长期的研究目标是为临床的发展做出贡献。 有用的机制为基础的干预措施，以治疗或预防心血管疾病在绝经后老龄女性。的 本R 03申请的总体目标是建立年龄依赖性E2/ERα信号传导的概念验证 在生理和病理生理条件下调节心脏中HDAC 2的表达。中央 假设内源性E2/ERα信号通过抑制HDAC 2而具有心脏保护作用 在绝经前女性中的表达。这个项目的基本原理是年龄概念的证明- 依赖E2/ERα介导的HDAC 2表达抑制和心脏保护将使随后的 明确的R 01研究旨在设计治疗或预防老年女性心脏病的策略。的 中心假设将通过2个特定目的进行检验：1）确定E2/ER α的年龄依赖性效应 心脏HDAC 2的表达。a）从正常男性分离的培养的人CM（HCM）， 和绝经后女性心室心脏组织将用于建立转录抑制， HDAC 2基因通过E2/ERα和（B）年轻和老年雌性和雄性小鼠心脏组织的作用， 用于确定心脏ER和HDAC 2基因表达的年龄和性别依赖性调节， 通过新颖的液滴数字PCR（ddPCR）、分子和生物化学技术，2)确定 卵巢切除术和E2对心脏功能和HDAC 2调节的功能影响 表达/活动。在这个目标中，将在药物诱导的CH中研究E2对HDAC 2阻遏的影响， 卵巢切除（年轻和老年）的雌性小鼠，利用超声心动图，收缩压 测量、ELISA、组织学和基因表达研究。本申请中提出的研究是 在申请人看来是创新的，因为它利用了新的ddPCR技术并研究了一种新的 E2/ERα介导的HDAC 2抑制在心脏转录水平的调控机制。这将 从而确定新的E2/ERα转录靶点及其在年轻和衰老心脏中的功能作用 女性这项拟议中的研究意义重大，因为它有望提供强有力的科学依据 继续研究和开发用于老年女性的E2组合药物。

Project Summary The risk of cardiovascular disease (CVD) increases in females with aging and falling estrogen (E2) levels during menopause, yet the beneficial effects of postmenopausal hormone-replacement therapy (HRT) on reducing the risk remain controversial. Estrogen mediates its protective effects by inducing its receptor ERα binding to E2-target genes. Dysregulation of epigenetic enzymes like histone deacetylases (HDACs) are implicated in pathological aging and class I HDAC2 functions as a positive regulator of cardiac hypertrophy (CH) in response to stress. The long-term research goal is to contribute toward the development of clinically useful mechanism-based interventions to treating or preventing CVD in postmenopausal aging females. The overall objective for this R03 application is to establish proof of concept of age dependent E2/ERα signaling regulating HDAC2 expression in heart under physiological and pathophysiological conditions. The central hypothesis is that endogenous E2/ERα signaling is cardioprotective through the inhibition of HDAC2 expression in premenopausal females. The rationale underlying this project is that proof of concept of age- dependent E2/ERα-mediated repression of HDAC2 expression and cardio protection will enable subsequent definitive R01 studies aimed at designing strategies to treat or prevent heart diseases in aging females. The central hypothesis will be examined with 2 Specific Aims: 1) Identify age-dependent effects of E2/ER alpha on cardiac HDAC2 expression. Under this aim a) cultured human CM (HCM) isolated from normal male, pre and postmenopausal female ventricular heart tissue will be utilized to establish transcriptional repression of HDAC2 gene via actions of E2/ERα and (b) young and old female and male mice heart tissues will be utilized to determine age- and sex-dependent regulation of cardiac ERs and HDAC2 gene expression and activity by novel Droplet Digital PCR (ddPCR), molecular and biochemical techniques. 2) Determine the functional consequences of ovariectomy and E2 on cardiac function and regulation of HDAC2 expression/activity. In this aim, effects of E2 on HDAC2 repression will be studied in drug–induced CH in ovariectomized (young and aged) female mice by utilizing echocardiography, systolic blood pressure measurements, ELISA, histology, and gene expression studies. The research proposed in this application is innovative in the applicant's opinion, because it utilizes new ddPCR technique and studies a novel regulatory mechanism of E2/ERα-mediated HDAC2 repression at the transcription level in heart. This will lead to define new E2/ERα transcriptional target and its functional role in the heart of young and aging females. The proposed research is significant because it is expected to provide strong scientific justification for the continued research and development of combinatorial drug with E2 for aging females.