Sun Yun, Chen Dan, Liu Fengjie, Liu Ting
Department of General Practice, The Second Hospital of Dalian Medical University, No. 467, Zhongshan Road, Dalian, People's Republic of China.
Biol Direct. 2025 Jul 1;20(1):76. doi: 10.1186/s13062-025-00670-7.
Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease characterized by excessive macrophage infiltration and extracellular matrix deposition. The progress of IPF is promoted by M2 macrophages which produce pro-fibrotic factors and induce fibroblast differentiation. SESN3 was upregulated in lung tissues of IPF patients and mice with bleomycin-induced pulmonary fibrosis. However, the role of SESN3 in IPF and its related mechanisms remain largely unknown.
Here, we used IL-4/13 to induce macrophage M2 polarization in RAW264.7 cells and constructed a mouse model of pulmonary fibrosis by intratracheal injection of bleomycin. Adenoviruses targeting SESN3 were constructed to infect RAW264.7 cells and BLM-induced mice to assess the function of SESN3 in macrophage M2 polarization in the progress of IPF and mRNA-seq and Co-IP-MS analysis were performed to find the downstream factors.
For in vitro experiments, SESN3 knockdown promoted the M2 polarization level, the release of pro-fibrosis factors and the activation of fibroblast, overexpression of SESN3 had an opposite trend. For in vivo experiments, the increased degree of pulmonary fibrosis in BLM mice was relieved after overexpression of SESN3. Meanwhile, overexpression of SESN3 repressed the increased macrophage M2 polarization level induced by BLM. Mechanically, FOSL2 was screened out through mRNA-seq and Co-IP-MS analysis due to its binding affinity with SESN3 and the observed downregulation of its downstream pro-fibrotic factor expression. The expression of FOSL2 in the nucleus was down-regulated after SESN3 overexpression. Under IL-4/13 treatment, the increased levels of macrophage M2 polarization and pro-fibrotic factors induced by SESN3 knockdown was recovered after knocking down FOSL2 in RAW264.7 cells.
In summary, our study suggested that SESN3 regulated the IPF process through inhibiting macrophage M2 polarization by targeting the activity of FOSL2.
特发性肺纤维化（IPF）是一种进行性肺部疾病，其特征为巨噬细胞过度浸润和细胞外基质沉积。M2巨噬细胞通过产生促纤维化因子并诱导成纤维细胞分化来促进IPF的进展。SESN3在IPF患者和博来霉素诱导的肺纤维化小鼠的肺组织中上调。然而，SESN3在IPF中的作用及其相关机制仍 largely 未知。
在此，我们使用IL-4/13诱导RAW264.7细胞中巨噬细胞M2极化，并通过气管内注射博来霉素构建肺纤维化小鼠模型。构建靶向SESN3的腺病毒以感染RAW264.7细胞和博来霉素诱导的小鼠，以评估SESN3在IPF进展中巨噬细胞M2极化中的功能，并进行mRNA测序和免疫共沉淀-质谱分析以寻找下游因子。
在体外实验中，敲低SESN3促进了M2极化水平、促纤维化因子的释放和成纤维细胞的活化，SESN3过表达则有相反的趋势。在体内实验中，SESN3过表达后，博来霉素小鼠肺纤维化的加重程度得到缓解。同时，SESN3过表达抑制了博来霉素诱导的巨噬细胞M2极化水平的升高。机制上，通过mRNA测序和免疫共沉淀-质谱分析筛选出FOSL2，因为它与SESN3具有结合亲和力，并且观察到其下游促纤维化因子表达下调。SESN3过表达后，FOSL2在细胞核中的表达下调。在IL-4/13处理下，在RAW264.7细胞中敲低FOSL2后，SESN3敲低诱导的巨噬细胞M2极化和促纤维化因子水平的升高得以恢复。
总之，我们的研究表明，SESN3通过靶向FOSL2的活性抑制巨噬细胞M2极化来调节IPF进程。
