Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, 39216, USA.
Department of Molecular Pharmacology and Physiology, University of South Florida, Tampa, FL, 33612, USA.
Basic Res Cardiol. 2019 Aug 15;114(5):37. doi: 10.1007/s00395-019-0746-x.
In response to myocardial infarction (MI), neutrophils (PMNs) are early responders that initiate the inflammatory reaction. Because macrophages and fibroblasts show polarization states after MI, we hypothesized PMNs also undergo phenotypic changes over the MI time course. The objective of the current study was to map the continuum of polarization phenotypes in cardiac neutrophils over the first week of MI. C57BL/6J male mice (3-6 months old) underwent permanent coronary artery ligation to induce MI, and PMNs were isolated from the infarct region at days 1, 3, 5, and 7 after MI. Day 0 served as a no MI negative control. Aptamer proteomics was performed on biological replicates (n = 10-12) for each time point. Day (D)1 MI neutrophils had a high degranulation profile with increased matrix metalloproteinase (MMP) activity. D3 MI neutrophil profiles showed upregulation of apoptosis and induction of extracellular matrix (ECM) organization. D5 MI neutrophils further increased their ECM reorganization profile. D7 MI neutrophils had a reparative signature that included expression of fibronectin, galectin-3, and fibrinogen to contribute to scar formation by stimulating ECM reorganization. Of note, fibronectin was a key modulator of degranulation, as it amplified MMP-9 release in the presence of an inflammatory stimulus. Our results indicate that neutrophils selectively degranulate over the MI time course, reflective of both their intrinsic protein profiles as well as the ECM environment in which they reside. MMPs, cathepsins, and ECM proteins were prominent neutrophil degranulation indicators.
针对心肌梗死（MI），中性粒细胞（PMN）是启动炎症反应的早期应答者。由于 MI 后巨噬细胞和成纤维细胞表现出极化状态，我们假设 PMN 也会在 MI 过程中经历表型变化。本研究的目的是在 MI 的第一周内描绘心脏中性粒细胞极化表型的连续变化。3-6 个月大的雄性 C57BL/6J 小鼠进行永久性冠状动脉结扎以诱导 MI，并在 MI 后第 1、3、5 和 7 天从梗死区域分离 PMN。第 0 天作为无 MI 的阴性对照。对每个时间点的生物学重复（n=10-12）进行适体蛋白质组学分析。MI 第 1 天的中性粒细胞脱颗粒程度较高，基质金属蛋白酶（MMP）活性增加。MI 第 3 天的中性粒细胞谱显示凋亡上调，并诱导细胞外基质（ECM）组织。MI 第 5 天的中性粒细胞进一步增加了 ECM 重组谱。MI 第 7 天的中性粒细胞具有修复特征，包括表达纤维连接蛋白、半乳糖凝集素-3 和纤维蛋白原，通过刺激 ECM 重组促进瘢痕形成。值得注意的是，纤维连接蛋白是脱颗粒的关键调节剂，因为它在存在炎症刺激时放大 MMP-9 的释放。我们的结果表明，中性粒细胞在 MI 过程中选择性脱颗粒，反映了它们内在的蛋白质谱以及它们所处的 ECM 环境。MMP、组织蛋白酶和 ECM 蛋白是突出的中性粒细胞脱颗粒指标。
