CTRP9通过MAPK/Drp1介导的线粒体分裂和AdipoR1诱导的免疫代谢增强巨噬细胞的胞葬作用。
CTRP9 Enhances Efferocytosis in Macrophages via MAPK/Drp1-Mediated Mitochondrial Fission and AdipoR1-Induced Immunometabolism.
作者信息
Song Cheng-Xiang, Chen Ji-Ying, Li Na, Guo Yuan
机构信息
Department of Cardiology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, People's Republic of China.
The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital of Shandong University, Jinan, 250012, People's Republic of China.
出版信息
J Inflamm Res. 2021 Mar 23;14:1007-1017. doi: 10.2147/JIR.S302944. eCollection 2021.
BACKGROUND
Clearance of apoptotic cells (ACs) by phagocytes (efferocytosis) suppresses post-apoptotic necrosis and alleviates inflammation. Defective efferocytosis induces diseases that include atherosclerosis and autoimmune diseases. C1q/TNF-related protein 9 (CTRP9), a novel adipokine, has been reported to protect against various cardiovascular disease; however, the effect of CTRP9 on efferocytosis has not been elucidated.
METHODS
- The efferocytosis of macrophages incubated with ACs with or without CTRP9 treatment was detected by flow cytometry (FCM) and immunostaining. The unengulfed ACs of CTRP9-KO and wild-type (WT) mice after dexamethasone injection were detected by TUNEL assay. 2. As mitochondrial fission is important for promoting efferocytosis, the effect of CTRP9 on mitochondrial fission was measured by fission/fusion-related proteins (MFN2, DRP1, MFF, and OPA1) and visualized by staining with MitoTracker. 3. On account of metabolism insults in engulfed macrophages, we conducted a two-stage efferocytosis assay, and the protective effects of CTRP9 on metabolism were investigated by Western blot.
RESULTS
CTRP9 significantly facilitated macrophage efferocytosis, and it promoted mitochondrial fission by increasing the expression of p-DRP1 (s616) and the translocation of DRP1 from the cytoplasm to the mitochondria. The p38/Jnk-MAPK pathway was activated after treatment with 1 μg/mL CTRP9. When we blocked the activation of MAPK signaling by SB203580 and SP600125, the mediated effect on p-DRP1 (s616) was reduced. Moreover, CTRP9 increased the levels of ABCA1, PPAR-y, HIF-1a and GLUT1, as well as the release of lactate in basal and engulfed macrophages, which revealed that the metabolism of macrophages was advanced. Apoptotic cell-conditioned media (ACCM) and ACs increased the expression of adiponectin receptor 1 (AdipoR1). Down-regulation of AdipoR1 by siRNA could abrogate the immunometabolism effects of CTRP9.
CONCLUSION
CTRP9 promoted efferocytosis in macrophages via MAPK/drp1-mediated mitochondrial fission and AdipoR1-induced immunometabolism.
背景
吞噬细胞清除凋亡细胞（噬菌作用）可抑制凋亡后坏死并减轻炎症。噬菌作用缺陷会引发包括动脉粥样硬化和自身免疫性疾病在内的多种疾病。C1q/TNF相关蛋白9（CTRP9）是一种新型脂肪因子，据报道可预防多种心血管疾病；然而，CTRP9对噬菌作用的影响尚未阐明。
方法
- 通过流式细胞术（FCM）和免疫染色检测经或未经CTRP9处理的巨噬细胞与凋亡细胞共孵育后的噬菌作用。用地塞米松注射后，通过TUNEL检测CTRP9基因敲除（KO）小鼠和野生型（WT）小鼠未被吞噬的凋亡细胞。2. 由于线粒体分裂对促进噬菌作用很重要，通过与分裂/融合相关蛋白（MFN2、DRP1、MFF和OPA1）检测CTRP9对线粒体分裂的影响，并用MitoTracker染色进行可视化观察。3. 鉴于被吞噬巨噬细胞中的代谢损伤，我们进行了两阶段噬菌作用检测，并通过蛋白质免疫印迹法研究CTRP9对代谢的保护作用。
结果
CTRP9显著促进巨噬细胞的噬菌作用，并通过增加p-DRP1（s616）的表达以及DRP1从细胞质向线粒体的转位来促进线粒体分裂。用1μg/mL CTRP9处理后，p38/Jnk-MAPK通路被激活。当我们用SB203580和SP600125阻断MAPK信号的激活时，对p-DRP1（s616）的介导作用减弱。此外，CTRP9增加了基础状态和被吞噬巨噬细胞中ABCA1、PPAR-γ、HIF-1α和GLUT1的水平以及乳酸的释放，这表明巨噬细胞的代谢得到了促进。凋亡细胞条件培养基（ACCM）和凋亡细胞增加了脂联素受体1（AdipoR1）的表达。通过小干扰RNA（siRNA）下调AdipoR1可消除CTRP9的免疫代谢作用。
结论
CTRP9通过MAPK/drp1介导的线粒体分裂和AdipoR1诱导的免疫代谢促进巨噬细胞的噬菌作用。
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