American Ginseng-mediated Autophagy and Suppression of Inflammation (Project 3)

摘要 慢性心力衰竭是各种心血管疾病(CVD)的最后一步，仍然是心血管疾病死亡的主要原因，无法治愈。到目前为止，通过阻断或抑制炎症细胞因子和氧化应激等过度激活的单一途径在心血管疾病中发挥作用的治疗方法被证明是无效的，甚至是有害的。在这种背景下，传统中药的治疗理念提出了一个新的研究方向，即通过协调多个信号通路来维持系统的动态平衡，而不是阻断或抑制单个过度激活的信号通路。然而，这一概念一直被批评为草药治疗CVD的神秘说法，因为发现相互矛盾，而且缺乏对草药治疗CVD的有效性和安全性的机理分析。事实上，草药预防适应性不良心脏重塑和心力衰竭的分子机制仍有待建立。 在国家补充和替代医学中心(NCCAM)的指导下，我们利用加拿大国家研究委员会、国家测量标准研究所(NRCC-INMS)的标准化西洋参提取物，从机械上探讨了人参的心脏保护作用。人参是人参属的根，在亚洲国家已被用作民间药物数千年。我们的发现有力地支持了一个新的工作假说，即西洋参通过协调心脏中的自噬活动和Nrf2信号来抑制氧化应激和炎症反应，以及随后的适应性不良心脏重构和功能障碍。为了验证这一假设，我们提出了以下三个具体目标： 目的1.探讨自噬和Nrf2在西洋参抑制巨噬细胞氧化应激和炎性细胞因子产生以及心肌细胞氧化应激、肥大生长和细胞死亡中的作用； 目的2.测定西洋参中协调自噬和Nrf2途径的活性成分，从而阻断体外氧化应激和炎症的恶性循环； 目的3.确定西洋参通过激活心肌自噬和Nrf2抑制适应性不良心肌肥大和功能障碍的活性成分； 这些实验将首次证明西洋参激活的自噬在西洋参激活的Nrf2介导的心脏保护中是必不可少的。总体而言，这一提议的结果不仅将为西洋参介导的心脏保护提供一个新的分子机制，而且还将为细分人参活性成分的心脏保护作用建立生物标志物。

Abstract Chronic heart failure, the final step of different cardiovascular diseases (CVD), remains the leading cause of cardiovascular death without a cure. To date, the therapeutic approaches by blocking or inhibiting over-activated single pathway such as inflammatory cytokines and oxidative stress which have been firmly established to play a causative role in CVD turn out to be ineffective or even harmful. In this context, the therapeutic concept of traditional herb medicine that aims to maintain systemic homeostasis by orchestrating multiple signaling pathways rather than blocking or inhibiting single over-activated signaling pathway raises a novel research direction. However, this concept has always been criticized as the 'mystical' claim for herb medicines to treat CVD, due to the contradictory findings and the lack of mechanistic analysis of herb medicine's efficacy and safety for the treatment of CVD. Indeed, the molecular mechanism by which herb medicines protect against maladaptive cardiac remodeling and heart failure remains to be established. Utilizing a standardized American ginseng extract from the National Research Council of Canada, Institute for National Measurement Standards (NRCC-INMS) under the guidelines of National Center for Complementary and Alternative Medicine (NCCAM), we have mechanistically explored the cardiac protective actions of ginseng, the root of genus Panax that has been used as a folk medicine for several thousand years in Asian countries. Our findings strongly support a novel working hypothesis that American ginseng suppresses oxidative stress and inflammatory responses, as well as the subsequent maladaptive cardiac remodeling and dysfunction via coordinating autophagic activity and Nrf2 signaling in the heart. To test this hypothesis, we propose three specific aims as follows: Aim 1. To determine role of autophagy and Nrf2 in regulating the American ginseng-mediated suppression of oxidative stress and inflammatory cytokine production in macrophages as well as oxidative stress, hypertrophic growth and cell death in cardiomyocytes; Aim 2. To determine the active components of American ginseng for the coordination of autophagy and Nrf2 pathway thereby blocking the vicious cycle of oxidative stress and inflammation in vitro; Aim 3. To determine the active components of American ginseng for the suppression of maladaptive cardiac hypertrophy and dysfunction via activating both myocardial autophagy and Nrf2 in the heart; These experiments will demonstrate for the first time that American ginseng-activated autophagy is essential for American ginseng-activated Nrf2-mediated cardiac protection. Overall, the outcome of this proposal will not only provide a novel molecular mechanism of American ginseng-mediated cardiac protection, but also establish biomarkers for the sub-fractionating of the active components of ginsengs for cardiac protection.