Liu Haijun, Guan Qingzhou, Zhao Peng, Li Jiansheng
Collaborative Innovation Center for Chinese Medicine and Respiratory Diseases co-constructedby Henan province & Education Ministry of People's Republic of China, Academy of Chinese Medical Sciences, Henan University of Traditional Chinese Medicine, Zhengzhou, Henan Province, China.
The First Affiliated Hospital of Henan University of Chinese Medicine, Zhengzhou, China.
Exp Lung Res. 2022 Apr 4:1-14. doi: 10.1080/01902148.2022.2055227.
Idiopathic pulmonary fibrosis (IPF) is an interstitial disease of unknown origin, characterized by tissue fibrosis, for which currently there is no effective treatment. Macrophages, the main immune cells in lung tissue, are involved in the whole process of pulmonary fibrosis. In recent years, intercellular transformation has led to wide spread concern among pulmonary fibrosis researchers. Macrophages with flexible heterogeneity and plasticity participate in different physiological processes in the body. Cell chemokine receptor 8 (CCR8) is expressed in a variety of cells and plays a significant chemotactic role in the induction of cell activation and migration. It can also promote the differentiation of macrophages under certain environmental conditions. The current study is intended to explore the role of CCR8 in macrophage to myofibroblast transdifferentiation (MMT) in IPF. We conducted experiments using CCR8-specific small interfering RNA (siRNA), an autophagy inhibitor (3-methyladenine, 3-MA), and an agonist (rapamycin) to explore the underlying mechanisms of macrophage transdifferentiation into myofibroblast cells in transforming growth factor-beta (TGF-β)-induced pulmonary fibrosis. TGF-β treatment increased the CCR8 protein level in a time- and dose-dependent manner in mouse alveolar macrophages, as well as macrophage transdifferentiation-related markers, including vimentin, collagen 1, and a-SMA, and cell migration. In addition, the levels of autophagy were enhanced in macrophages treated with TGF-β. We found that 3-MA, an autophagy inhibitor, decreased the expression levels of macrophage transdifferentiation-related markers and attenuated cell migration. Furthermore, the inhibition of CCR8 via -specific siRNA reduced the levels of autophagy and macrophage transdifferentiation-related markers, and inhibited the cell migration. Enhancing autophagy with rapamycin attenuated the inhibition effect of -specific siRNA on macrophage migration and the increase in myofibroblast marker proteins. Our findings showed that the macrophages exposed to TGF-β had the potential to transdifferentiate into myofibroblasts and CCR8 was involved in the process. The effect of CCR8 on TGF-β-induced macrophage transdifferentiation occurs mainly through autophagy. Targeting CCR8 may be a novel therapeutic strategy for the treatment of IPF.
特发性肺纤维化（IPF）是一种病因不明的间质性疾病，其特征为组织纤维化，目前尚无有效治疗方法。巨噬细胞是肺组织中的主要免疫细胞，参与肺纤维化的全过程。近年来，细胞间转化引起了肺纤维化研究人员的广泛关注。具有灵活异质性和可塑性的巨噬细胞参与体内不同的生理过程。细胞趋化因子受体8（CCR8）在多种细胞中表达，在诱导细胞活化和迁移中发挥重要的趋化作用。在特定环境条件下，它还能促进巨噬细胞的分化。当前研究旨在探讨CCR8在IPF中巨噬细胞向肌成纤维细胞转分化（MMT）过程中的作用。我们使用CCR8特异性小干扰RNA（siRNA）、自噬抑制剂（3-甲基腺嘌呤，3-MA）和激动剂（雷帕霉素）进行实验，以探究在转化生长因子-β（TGF-β）诱导的肺纤维化中巨噬细胞转分化为肌成纤维细胞的潜在机制。TGF-β处理以时间和剂量依赖性方式增加了小鼠肺泡巨噬细胞中CCR8蛋白水平，以及巨噬细胞转分化相关标志物，包括波形蛋白、胶原蛋白1和α-平滑肌肌动蛋白（α-SMA），并促进了细胞迁移。此外，TGF-β处理的巨噬细胞中自噬水平增强。我们发现，自噬抑制剂3-MA降低了巨噬细胞转分化相关标志物的表达水平，并减弱了细胞迁移。此外，通过特异性siRNA抑制CCR8降低了自噬水平和巨噬细胞转分化相关标志物水平，并抑制了细胞迁移。用雷帕霉素增强自噬减弱了特异性siRNA对巨噬细胞迁移的抑制作用以及肌成纤维细胞标志物蛋白的增加。我们的研究结果表明，暴露于TGF-β的巨噬细胞具有转分化为肌成纤维细胞的潜力，且CCR8参与了这一过程。CCR8对TGF-β诱导的巨噬细胞转分化的作用主要通过自噬发生。靶向CCR8可能是治疗IPF的一种新的治疗策略。
