Pathogenesis of Cardiopulmonary Fibrosis Associated with Heart Failure in the Elderly

项目摘要/摘要 与衰老相关的心脏和肺组织的不良重构在慢性阻塞性肺疾病患者中得到越来越多的认识 心衰并保留射血分数(HFpEF)。HFpEF与纤维化的发生发展有关 并降低了这些重要结构的顺应性(增加了刚度)。反过来，这种结构刚性导致 工作量增加，最终导致心力衰竭，临床结果不佳。人们对这些基础知识知之甚少 这种组织僵硬发生的机制。我们已经找到了提升表达能力的证据 组织谷氨酰胺转氨酶(TG2)活性在衰老和慢性疾病中的作用 心脏压力超负荷，伴随糖酵解代谢增强而发生。由于TG2已知会参与 在蛋白质交联和促进纤维化形成方面，我们假设这种衰老介导的增强 TG2通过糖酵解应激启动了各种生物事件，包括成纤维细胞的激活和 细胞外基质蛋白胶原沉积和交联性导致组织僵硬的形成 实验性高频脉冲电场。我们希望通过TG2活动的干预来探索这一新的假说 可能为老年性HFpEF提供一种新的治疗途径。在具体目标1中，我们将利用衰老 并在体外对照成纤维细胞，直接探讨衰老相关生物通路对细胞生长的影响 糖酵解、TG2、赖氨酸氧化酶(LOX)、基质蛋白改变与细胞的机制关系 信号和生理功能。预期结果：这些体外研究将促进我们的理解 关于介导TG2诱导和相关下游信号的上游衰老相关机制 小路。在特定目标2中，我们将使用野生型小鼠和衰老加速小鼠(SAM)模型 包括易感(SAMP8)和耐药(SAMR1)菌株，有或没有心脏左侧压力超负荷 评估衰老相关的在体分子和生理反应的脑室(主动脉收缩) 心脏和肺组织重塑、纤维化和僵硬。此外，我们将使用这些老化的 评估TG2抑制剂ERW1041E对上述病理生理反应影响的小鼠模型 测试TG2作为衰老依赖的组织纤维化和HFpEF的重要介体的有效性。我们会 确定TG2介导的胶原堆积和LOX介导的胶原氧化在心脏中的程度 利用新的体内成像技术对这些小鼠的肺和肺组织进行研究，并进一步将它们与 纤维化进展和缓解。此外，还将评估TG2介导的基质蛋白交联性 使用一种非侵入性的生物检测。预期结果：我们希望这些研究将为 老化的心脏和肺组织纤维化和僵硬的发生机制。意义：结果 我们的研究可能会导致在人类中使用类似的技术来评估衰老早期阶段的存在。 相关的HFpEF和相关治疗的有效性，旨在抑制组织纤维化。

Project Summary/Abstract Aging-related adverse remodeling in cardiac and pulmonary tissues is increasingly recognized in patients with heart failure with preserved ejection fraction (HFpEF). HFpEF is associated with the development of fibrosis and decreased compliance (increased stiffness) of these vital structures. In turn, this structural rigidity results in increased work load and eventual HF with poor clinical outcomes. Little is known about the basic mechanism by which this tissue stiffness occurs. We have found evidence for elevation of expression and activity of tissue transglutaminase (TG2) in age-dependent pathologies including senescence and chronic cardiac pressure overload, occurring with enhanced glycolytic metabolism. Since TG2 is known to participate in protein cross-linking and stimulation of fibrogenesis, we hypothesize that this aging-mediated enhancement of TG2 through glycolytic stress sets in motion a variety of biologic events, including fibroblast activation and extracellular matrix protein collagen deposition and cross-linking that lead to development of tissue stiffness in experimental HFpEF. We wish to explore this novel hypothesis with the idea that intervention of TG2 activity may provide a new therapeutic approach for age-related HFpEF. In Specific Aim 1, we will utilize senescent and control fibroblasts in vitro to directly explore the influence of aging-related biologic pathways on mechanistic relationships between glycolysis, TG2, lysyl oxidase (LOX), matrix protein alteration and cell signaling and physiologic function. Expected outcome: These in vitro studies will advance our understanding about upstream aging-related mechanisms that mediate TG2 induction and associated downstream signaling pathways. In Specific Aim 2, we will use wild-type mice and a senescent-accelerated mouse (SAM) model including prone (SAMP8) and resistant (SAMR1) strains with or without pressure-overload of the cardiac left ventricle (constriction of the aorta) to assess aging-related in vivo molecular and physiologic responses of cardiac and pulmonary tissue remodeling, fibrosis and stiffness. Additionally, we will use these senescent mouse models to assess the influence of ERW1041E, a TG2 inhibitor, on these pathophysiological responses to test validation of TG2 as a significant mediator of aging-dependent tissue fibrosis and HFpEF. We will determine the extent of TG2-mediated collagen accumulation and LOX-mediated collagen oxidation in cardiac and pulmonary tissues in these mice with use of novel in vivo imaging techniques and further relate them to fibrogenic progression and remission. Further, TG2-mediated matrix protein crosslinking will be assessed using a non-invasive bioassay. Expected outcome: We hope that these studies will provide new insights into mechanisms by which tissue fibrosis and stiffness occur in aging hearts and lungs. Significance: The results of our studies may lead to similar techniques in humans to assess the presence of early stages of aging- associated HFpEF and effectiveness of related therapy directed toward inhibition of tissue fibrosis.