Duan Jia-Xi, Zhou Yong, Zhou Ai-Yuan, Guan Xin-Xin, Liu Tian, Yang Hui-Hui, Xie Hui, Chen Ping
Department of Respiratory Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, Hunan, China; Research Unit of Respiratory Disease, Central South University, Changsha 410011, Hunan, China; Diagnosis and Treatment Center of Respiratory Disease, Central South University, Changsha 410011, Hunan, China.
Department of Physiology, Xiangya School of Medicine, Central South University, Changsha 410078, Hunan, China.
Mol Immunol. 2017 Nov;91:105-113. doi: 10.1016/j.molimm.2017.08.020. Epub 2017 Sep 8.
Acute lung injury (ALI) is a condition resulting from direct or indirect lung injury associated with high mortality and morbidity. The phenotype of macrophages in lung contributes to the pathological progress of ALI. Calcitonin gene-related peptide (CGRP) is one of the most abundant neuropeptides in lung, and attenuates lipopolysaccharide (LPS)-induced ALI in rats. However, the exact effect of CGRP on the activation of macrophages remains unknown. Here we investigate the effect of CGRP on the macrophages activation and inflammation in murine macrophages in vitro. We found that LPS increased the expression of CGRP in a LPS-induced ALI murine model and LPS-stimulated murine macrophages. Although CGRP didn't alter the expression of tumor necrosis factor-α (a marker of pro-inflammatory phenotype of macrophages, M1 macrophages) or Arginase 1 (Arg1, a marker of M2 macrophages) in non-differentiated macrophages, CGRP significantly reduced the NLRP3 and pro-IL-1β mRNA expression induced by LPS, as well as NLRP3 protein and IL-1β secretion induced by LPS+ATP in macrophages in vitro. On the other hand, CGRP dramatically enhanced the Arg1 expression and activity induced by IL-4 in the time- and dose-dependent manners. CGRP also promoted the expression of markers of M2 macrophages (IL-10, Fizz1 and Mrc1) induced by IL-4 in murine macrophages. These effects of CGRP were also observed in primary murine peritoneal macrophages. In addition, we found that CGRP regulated macrophages polarization partially through calmodulin, PKC and PKA pathways. Specifically, CGRP could inhibit the degradation of I-κB induced by LPS, and enhance the phosphorylation of STAT6 induced by IL-4 in macrophages. In conclusion, our results indicate that CGRP regulates macrophage polarization and inhibits inflammation in murine macrophages.
急性肺损伤（ALI）是一种由直接或间接肺损伤导致的病症，具有高死亡率和发病率。肺中巨噬细胞的表型有助于ALI的病理进展。降钙素基因相关肽（CGRP）是肺中含量最丰富的神经肽之一，可减轻大鼠脂多糖（LPS）诱导的ALI。然而，CGRP对巨噬细胞活化的确切作用尚不清楚。在此，我们在体外研究CGRP对小鼠巨噬细胞中巨噬细胞活化和炎症的影响。我们发现在LPS诱导的ALI小鼠模型和LPS刺激的小鼠巨噬细胞中，LPS增加了CGRP的表达。虽然CGRP在未分化的巨噬细胞中未改变肿瘤坏死因子-α（巨噬细胞促炎表型的标志物，M1巨噬细胞）或精氨酸酶1（Arg1，M2巨噬细胞的标志物）的表达，但CGRP显著降低了LPS诱导的NLRP3和前白细胞介素-1β mRNA表达，以及体外巨噬细胞中LPS + ATP诱导的NLRP3蛋白和白细胞介素-1β分泌。另一方面，CGRP以时间和剂量依赖性方式显著增强了IL-4诱导的Arg1表达和活性。CGRP还促进了IL-4在小鼠巨噬细胞中诱导的M2巨噬细胞标志物（IL-10、Fizz1和Mrc1）的表达。在原代小鼠腹腔巨噬细胞中也观察到了CGRP的这些作用。此外，我们发现CGRP部分通过钙调蛋白、蛋白激酶C和蛋白激酶A途径调节巨噬细胞极化。具体而言，CGRP可抑制LPS诱导的I-κB降解，并增强巨噬细胞中IL-4诱导的信号转导和转录激活因子6（STAT6）的磷酸化。总之，我们的结果表明CGRP调节小鼠巨噬细胞的极化并抑制炎症。
