Collagen-derived peptides to target inflammation in myocardial infarction

项目摘要 心肌梗死（MI）导致疤痕的产生，疤痕主要由心脏细胞外基质构成。 矩阵（ECM）。ECM的降解和沉积之间的平衡是临床预后的强有力预测因素。 结果。ECM降解通过基质金属蛋白酶（MMP）发生;并且ECM沉积通过基质金属蛋白酶（MMP）发生。 心脏成纤维细胞ECM降解和沉积均促进不良重塑和向心脏进展 失败在MMP家族中，MMP-9已被报道为心功能不全的预后指标， 心肌梗死（MI）患者;因为MMP-9水平与患者死亡率直接相关。因此， 抑制心肌梗死后MMP-9的作用早已被认识。然而，使用整体MMP-9抑制的临床试验 由于缺乏MMP抑制剂特异性和MMP-9在几种重要的免疫调节中的重要性， 流程. 我们最近发现了一种ECM衍生肽（p1159），作为竞争性和特异性MMP-9底物。 在此，我们建议使用p1159来调节MMP-9裂解的天然底物后MI。这种方法 不抑制MMP-9活性，使其参与基本过程;相反，它调节MMP-9 蛋白水解能力减少促进炎症和抑制修复的内源性底物的裂解。 合成肽p1159是由MMP-9产生的天然形成的片段C-1158/59的模拟物 MI后胶原蛋白的裂解。在人类中，MI后内源性C-1158/59的血浆水平与较低的 左心室充盈压，表明C-1158/59的治疗潜力。事实上，用外源性 MI后p1159显示LV扩张较少，炎症和纤维化减少，心脏功能改善。在 在体外，我们鉴定了整合素α4（Itga 4）作为肽受体。虽然我们知道外源性递送是有益的， p1159如何调节MI后炎症和ECM沉积还没有被机械地剖析。 因此，该建议的中心假设是，p1159通过以下方式减弱MI后的不良重塑： 作为竞争性底物以减少促进炎症所必需的底物的MMP-9蛋白水解 和ECM沉积。阐明p1159在心肌梗死后的作用方式和信号通路， 在这种情况下，我们将使用细胞特异性Itga 4转基因动物来鉴定p1159脾气的机制。 MI后炎症反应，调节心脏成纤维细胞信号传导以减少ECM分泌;和 促进巨噬细胞-成纤维细胞串扰。

PROJECT SUMMARY Myocardial infarction (MI) leads to the generation of a scar that is mostly constituted by cardiac extracellular matrix (ECM). The balance between degradation and deposition of ECM is a strong predictor of clinical outcomes. ECM degradation occurs by matrix metalloproteinases (MMPs); and ECM deposition occurs by cardiac fibroblasts. Both ECM degradation and deposition promote adverse remodeling and progression to heart failure. Within the MMP family, MMP-9 has been reported as a prognostic indicator of cardiac dysfunction in myocardial infarction (MI) patients; as MMP-9 levels directly associate with patient mortality. Thus, the advantage of inhibiting MMP-9 after MI has been long recognized. However, clinical trials using global MMP-9 inhibition have mostly failed both due to lack of MMP inhibitor specificity and importance of MMP-9 in several essential processes. We recently identified an ECM-derived peptide (p1159) that acts as a competitive and specific MMP-9 substrate. Herein, we propose use of p1159 to modulate MMP-9 cleavage of native substrates post-MI. This approach does not inhibit MMP-9 activity, allowing it to participate in essential processes; instead, it modulates MMP-9 proteolytic capacity to reduce cleavage of endogenous substrates that promote inflammation and inhibit repair. The synthetic peptide p1159 is a mimetic of the naturally formed fragment C-1158/59 generated by MMP-9 cleavage of collagen post-MI. In humans, plasma levels of endogenous C-1158/59 post-MI correlate with lower left ventricle filling pressure, indicating a therapeutic potential of C-1158/59. Indeed, mice treated with exogenous p1159 post-MI display less LV dilation, reduced inflammation and fibrosis, and improved cardiac function. In vitro, we identified integrin α4 (Itga4) as a peptide receptor. While we know that exogenous delivery is beneficial, how p1159 regulates post-MI inflammation and ECM deposition has not been mechanistically dissected. Accordingly, the central hypothesis of this proposal is that p1159 blunts adverse remodeling after MI by serving as a competitive substrate to reduce MMP-9 proteolysis of substrates necessary for promotion of inflammation and ECM deposition. To elucidate the mode-of-action and signaling pathways mediated by p1159 in the post-MI setting, we will use cell-specific Itga4 transgenic animals to identify the mechanisms whereby p1159 tempers the post-MI inflammatory response, modulates cardiac fibroblast signaling to reduce ECM secretion; and promotes macrophage-fibroblast crosstalk.