热休克蛋白27（HSP27）在肺纤维化（PF）期间过度表达，并加重了PF的病情；然而，在PF期间HSP27的上调和HSP27抑制的治疗策略尚不清楚。我们开发了一个模拟临床立体定向体放射治疗（SBRT）的小鼠模型，并验证了RIPF的诱导。同时使用了HSP25（HSP27的小鼠形式）转基因（TG）和LLC1源性正位肺肿瘤模型。使用了患有RIPF和特发性肺纤维化的患者的肺组织，以及各种纤维化小鼠模型的肺组织和适当的细胞系系统。利用公共基因表达数据集进行治疗反应率分析。此外，还使用了一种人造小分子HSP27抑制剂J2。 在PF期间，HSP27表达及其磷酸化形式（pHSP27）增加。SMAD特异性E3泛素蛋白酶配体2（Smurf2）mRNA表达下降，这与HSP27的泛素降解有关，是pHSP27表达增加的原因。此外，在PF模型中发现miRNA15b的表达增加，同时Smurf2 mRNA表达减少。在PF动物的肺组织、放射治疗正位肺癌模型和患者的PF组织中观察到pHSP27和Smurf2之间的反向相关性。此外，一种HSP27抑制剂与HSP27蛋白交联以改善PF，在目标PF的上皮至间充质转化（EMT）阶段时更为有效。我们的研究结果揭示了HSP27在PF期间上调的机制，并提供了一种克服PF的HSP27抑制治疗策略。© 2023.作者（们）发表。

Heat shock protein 27 (HSP27) is overexpressed during pulmonary fibrosis (PF) and exacerbates PF; however, the upregulation of HSP27 during PF and the therapeutic strategy of HSP27 inhibition is not well elucidated.We have developed a mouse model simulating clinical stereotactic body radiotherapy (SBRT) with focal irradiation and validated the induction of RIPF. HSP25 (murine form of HSP27) transgenic (TG) and LLC1-derived orthotropic lung tumor models were also used. Lung tissues of patients with RIPF and idiopathic pulmonary fibrosis, and lung tissues from various fibrotic mouse models, as well as appropriated cell line systems were used. Public available gene expression datasets were used for therapeutic response rate analysis. A synthetic small molecule HSP27 inhibitor, J2 was also used.HSP27 expression with its phosphorylated form (pHSP27) increased during PF. Decreased mRNA expression of SMAD-specific E3 ubiquitin-protein ligase 2 (Smurf2), which is involved in ubiquitin degradation of HSP27, was responsible for the increased expression of pHSP27. In addition, increased expression of miRNA15b was identified with decreased expression of Smurf2 mRNA in PF models. Inverse correlation between pHSP27 and Smurf2 was observed in the lung tissues of PF animals, an irradiated orthotropic lung cancer models, and PF tissues from patients. Moreover, a HSP27 inhibitor cross-linked with HSP27 protein to ameliorate PF, which was more effective when targeting the epithelial to mesenchymal transition (EMT) stage of PF.Our findings identify upregulation mechanisms of HSP27 during PF and provide a therapeutic strategy for HSP27 inhibition for overcoming PF.© 2023. The Author(s).