Hitscherich Pamela G, Xie Lai-Hua, Del Re Dominic, Lee Eun Jung
Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey.
Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, New Jersey.
Physiol Rep. 2019 Jul;7(13):e14137. doi: 10.14814/phy2.14137.
Following myocardial infarction (MI), myocardial inflammation plays a crucial role in the pathogenesis of MI injury and macrophages are among the key cells activated during the initial phases of the host response regulating the healing process. While macrophages have emerged as attractive effectors in tissue injury and repair, the contribution of macrophages on cardiac cell function and survival is not fully understood due to complexity of the in vivo inflammatory microenvironment. Understanding the key cells involved and how they communicate with one another is of paramount importance for the development of effective clinical treatments. Here, novel in vitro myocardial inflammation models were developed to examine how both direct and indirect interactions with polarized macrophage subsets present in the post-MI microenvironment affect cardiomyocyte function. The indirect model using conditioned medium from polarized macrophage subsets allowed examination of the effects of macrophage-derived factors on stem cell-derived cardiomyocyte function for up to 3 days. The results from the indirect model demonstrated that pro-inflammatory macrophage-derived factors led to a significant downregulation of cardiac troponin T (cTnT) and sarcoplasmic/endoplasmic reticulum calcium ATPase (Serca2) gene expression. It also demonstrated that inhibition of macrophage-secreted matricellular protein, osteopontin (OPN), led to a significant decrease in cardiomyocyte store-operated calcium entry (SOCE). In the direct model, stem cell-derived cardiomyocytes were co-cultured with polarized macrophage subsets for up to 3 days. It was demonstrated that anti-inflammatory macrophages significantly increased cardiomyocyte Ca fractional release while macrophages independent of their subtypes led to significant downregulation of SOCE response in cardiomyocytes. This study describes simplified and controlled in vitro myocardial inflammation models, which allow examination of potential beneficial and deleterious effects of macrophages on cardiomyocytes and vise versa. This can lead to our improved understanding of the inflammatory microenvironment post-MI, otherwise difficult to directly investigate in vivo or by using currently available in vitro models.
心肌梗死后，心肌炎症在心肌损伤的发病机制中起关键作用，巨噬细胞是宿主反应初始阶段被激活的关键细胞之一，参与调节愈合过程。虽然巨噬细胞已成为组织损伤和修复中有吸引力的效应细胞，但由于体内炎症微环境的复杂性，巨噬细胞对心脏细胞功能和存活的贡献尚未完全明确。了解其中涉及的关键细胞以及它们如何相互作用对于开发有效的临床治疗方法至关重要。在此，我们建立了新型体外心肌炎症模型，以研究与心肌梗死后微环境中存在的极化巨噬细胞亚群的直接和间接相互作用如何影响心肌细胞功能。使用来自极化巨噬细胞亚群的条件培养基的间接模型能够检测巨噬细胞衍生因子对干细胞衍生心肌细胞功能长达3天的影响。间接模型的结果表明，促炎巨噬细胞衍生因子导致心肌肌钙蛋白T（cTnT）和肌浆网/内质网钙ATP酶（Serca2）基因表达显著下调。该结果还表明，抑制巨噬细胞分泌的基质细胞蛋白骨桥蛋白（OPN）会导致心肌细胞储存性钙内流（SOCE）显著降低。在直接模型中,将干细胞衍生的心肌细胞与极化巨噬细胞亚群共培养长达3天。结果表明，抗炎巨噬细胞显著增加心肌细胞钙分数释放，而无论其亚型如何，巨噬细胞均导致心肌细胞SOCE反应显著下调。本研究描述了简化且可控的体外心肌炎症模型，该模型能够检测巨噬细胞对心肌细胞潜在的有益和有害影响，反之亦然。这有助于我们更好地理解心肌梗死后的炎症微环境，否则很难在体内直接研究或使用现有的体外模型进行研究。
