Center for Cononary Artery Disease, Beijing Anzhen Hospital, Capital Medical University, Beijing 100029, PR China.
Department of Health Care for Cadres, Beijing Jishuitan Hospital, Beijing 100035, PR China.
Microvasc Res. 2022 Mar;140:104279. doi: 10.1016/j.mvr.2021.104279. Epub 2021 Nov 10.
CC chemokine receptor 5 (CCR5) has been demonstrated to be correlated to activation of pro-inflammatory immune cells and tissue injury. This study focused on the role of CCR5 in myocardial injury in rats with diabetic cardiomyopathy (DCM) and the mechanism of action.
A rat model of DCM was induced by streptozotocin (STZ). CCR5 was knocked down in rats to determine its role in myocardial injury and immune cell infiltration. The upstream regulators of CCR5 were bioinformatically predicted and the binding between nuclear receptor subfamily 4 group A member 2 (NR4A2) and CCR5 was validated. The portion of M1 and M2 macrophages in tissues was determined by flow cytometry or double-labeling immunofluorescence. Rat bone marrow mononuclear cells (BMMCs) were treated with granulocyte/macrophage colony stimulating factor (GM-CSF/M-CSF) and co-cultured with H9C2 cells for in vitro experiments.
STZ-treated rats had impaired cardiac function and increased levels of creatine kinase-MB, cardiac troponin I and lactate dehydrogenase. CCR5 inhibition significantly alleviated myocardial injury in rats and reduced the portion of M1 macrophages in rat cardiac tissues. NR4A2, which could suppress CCR5 transcription, was poorly expressed in rats with DCM. NR4A2 overexpression played a similar myocardium-protective role in rats. In vitro, overexpression of NR4A2 induced M2 polarization of macrophages, which protected the co-cultured H9C2 cells from high glucose-induced damage, but the protective role was blocked after CCR5 overexpression.
This study demonstrated that NR4A2 suppresses CCR5 expression and promotes M2 polarization of macrophages to alleviate cardiomyocyte loss and myocardial injury.
CC 趋化因子受体 5（CCR5）已被证明与促炎免疫细胞的激活和组织损伤有关。本研究重点探讨了 CCR5 在糖尿病心肌病（DCM）大鼠心肌损伤中的作用及其作用机制。
用链脲佐菌素（STZ）诱导大鼠 DCM 模型。敲低大鼠 CCR5 以确定其在心肌损伤和免疫细胞浸润中的作用。通过生物信息学预测 CCR5 的上游调节因子，并验证核受体亚家族 4 组 A 成员 2（NR4A2）与 CCR5 的结合。通过流式细胞术或双标记免疫荧光法测定组织中 M1 和 M2 巨噬细胞的比例。用粒细胞/巨噬细胞集落刺激因子（GM-CSF/M-CSF）处理大鼠骨髓单核细胞（BMMCs），并与 H9C2 细胞共培养进行体外实验。
STZ 处理的大鼠心功能受损，肌酸激酶同工酶-MB、心肌肌钙蛋白 I 和乳酸脱氢酶水平升高。CCR5 抑制显著减轻大鼠心肌损伤，减少大鼠心脏组织中 M1 巨噬细胞的比例。NR4A2 可抑制 CCR5 转录，但在 DCM 大鼠中表达水平较低。NR4A2 过表达在大鼠中发挥类似的心肌保护作用。体外，NR4A2 过表达诱导巨噬细胞 M2 极化，保护共培养的 H9C2 细胞免受高糖诱导的损伤，但 CCR5 过表达后阻断了其保护作用。
本研究表明，NR4A2 抑制 CCR5 的表达，促进巨噬细胞 M2 极化，减轻心肌细胞丢失和心肌损伤。
