HSPs, Inflammatory Response and Cardiovascular Disease

描述(由申请人提供)：这项建议解决了一个范式转变：细胞外热休克蛋白(HSP)是促炎和促凋亡的。热休克蛋白可预防或改善损伤；然而，有证据表明这些蛋白质具有促炎作用。细胞外HSP60通过Toll样受体(TLR)激活先天免疫系统，导致细胞因子的产生。热休克蛋白抗体在人群中被发现，在那些患有心血管疾病的人中更普遍，就像血浆中热休克蛋白60的存在一样。在预先存在的炎性损伤的背景下，通过表达HSPs来诱导热休克反应，结果不是保护，而是细胞死亡。我们假设细胞外HSP60可以作为心血管系统炎症的诱导剂，并且炎症可以矛盾地抑制HSP对损伤的反应，或者将热休克反应的诱导从保护转变为有害。我们将在3个特定目标中解决这个问题：1.确定HSP60在心脏炎症中的作用-HSP60是TLR-4的配体，可以激活先天免疫系统，导致细胞因子的产生。在成人心肌细胞中，我们将确定HSP60的结合，确定HSP60的促凋亡作用，以及它对细胞因子产生的影响。2.确定重复性损伤如何与热休克反应相互作用，将其从保护性转化为促凋亡-通过炎症刺激和热休克蛋白诱导的损伤导致的顺序损伤导致细胞凋亡，而不是保护。我们发现，包括肿瘤坏死因子-α和热休克蛋白60在内的炎性刺激可诱导细胞凋亡，当随后发生热休克时，细胞凋亡率大大增加。因此，HSP60可以为心血管系统的损伤做好准备。实验将研究肿瘤坏死因子-α在热休克后的影响，确定这如何不成比例地增加损伤，以及HSP60如何导致细胞凋亡。3.找出衰竭心脏热休克蛋白60升高的机制(S)。我们假设HSPs的转录因子HSF-1在心力衰竭时被ERK1和GSK3失活，而HSP60表达的增加是由NFKB驱动的。反过来，心力衰竭时的细胞外HSP60会导致炎症和NFKB的激活。工作将涉及HSF-1的修饰和功能，以及HSP表达的控制。PI研究的长期目标是了解热休克蛋白在心脏损伤中的作用，从而进一步深入了解如何预防和治疗心脏损伤。

DESCRIPTION (provided by applicant): This proposal addresses a paradigm shift: that extracellular heat shock proteins (HSP) are pro-inflammatory and pro-apoptotic. HSPs prevent or ameliorate injury; however, there is evidence of a pro-inflammatory side to these proteins. Extracellular HSP60 is activates the innate immune system via the toll-like receptors (TLR), leading to the production of cytokines. Antibodies to HSPs are found in the population, and more prevalent in those with cardiovascular disease, as is the presence of HSP60 in the plasma. Induction of the heat shock response with expression of HSPs in the setting of a pre-existing inflammatory injury, results not in protection, but in cell death. We hypothesize that extracellular HSP60 can function as an inducer of inflammation in the cardiovascular system, and that inflammation can paradoxically inhibit the HSP response to injury, or convert the induction of the heat shock response from protective to harmful. We will address this in 3 Specific Aims: 1. Define the role of HSP60 in cardiac inflammation- HSP60 is a ligand forTLR-4 and can activate the innate immune system resulting in the production of cytokines. In adult cardiac myocytes, we will characterize the binding of HSP60, define the pro-apoptotic effect of HSP60 and as well as its effect on cytokine production. 2. Determine how repetitive injury interacts with the heat shock response to convert it from protective to pro-apoptotic- Sequential injury by an inflammatory stimulus followed by a HSP inducing injury results in apoptosis rather than protection. We have found that inflammatory stimuli, including TNF-alpha and HSP60, induce apoptosis, and when followed by heat shock, greatly increase apoptosis. Thus, HSP60 can prime the cardiovascular system for injury. Experiments will study the effect of TNF-alpha followed by heat shock, determine how this disproportionately increases injury, and how HSP60 causes apoptosis. 3. Identify the mechanism (s) leading to increased HSP60 in the failing heart. We hypothesize that HSF-1, a transcription factor for HSPs, is inactivated in heart failure by ERK1 and GSK3, and that increased HSP60 expression is driven by NFKB. In turn, extracellular HSP60 in heart failure causes inflammation and activation of NFKB. Work will address HSF-1 modification and function, and control of HSP expression. The long term goal of the Pi's research is to understand the role of heat shock proteins in cardiac injury, and thus, to achieve further insights into how to prevent as well as treat cardiac injury.