Huang Jie-Rou, Chen Liang, Li Chao-Qian
Department of Respiratory Medicine, the First Affiliated Hospital of Guangxi Medical University, Nanning, China.
Department of Rheumatology and Immunology, Hunan Provincial People's Hospital, the First-Affiliated Hospital of Hunan Normal University, Changsha, China.
Adv Clin Exp Med. 2025 Feb;34(2):211-225. doi: 10.17219/acem/186365.
Patients with rheumatoid arthritis-associated interstitial lung disease (RA-ILD) are characterized by severe pulmonary fibrosis and immune dysregulation. Heat shock protein 90 (HSP90) is involved in the progression of pulmonary fibrosis and the immune response.
This study aimed to explore whether HSP90 regulates the development of RA-ILD and its underlying mechanism.
In vivo, collagen-induced arthritis (CIA)-mice were treated with bleomycin (BLM) to establish an arthritic mouse model of pulmonary fibrosis. In vitro, human lung fibroblast 1 (HLF1) was exposed to transforming growth factor beta 1 (TGF-β1) to simulate an RA-ILD model. The RA-ILD models were treated with the HSP90 inhibitor ethoxyquin (EQ) to explore the potential mechanism of HSP90 in RA-ILD. Histopathological analysis was performed, and pulmonary fibrosis was evaluated. The differentiation of M1/M2 macrophages and Th1/Th17/Treg cells was assessed. The role of the TGF-β/Smad2/3 pathway in EQ-mediated RA-ILD progression was also explored.
HSP90α and HSP90β were upregulated in the RA-ILD models. Ethoxyquin mitigated arthritis in BLM-CIA mice, and reduced the expression of alpha-smooth muscle actin (α-SMA), collagen I (Col-1) and fibronectin (FN), as well as hydroxyproline content, thereby relieving pulmonary fibrosis. In addition, EQ increased M1 macrophages and inducible nitric oxide synthase (iNOS) and tumor necrosis factor alpha (TNF-α) levels; conversely, EQ decreased M2 macrophages and vascular endothelial growth factor (VEGF)-A and TGF-β1 contents. It also decreased Th17 (interleukin (IL)-17) while increasing Th1 (interferon gamma (IFN-γ)) and Treg (Foxp3), and restricted the expression of transforming growth factor beta type receptor I and II (TGF-βRI and TGF-βRII) and the phosphorylation of Smad2 and Smad3.
This study revealed that EQ regulated pulmonary fibrosis and cellular immunity by inhibiting HSP90, appearing to act through the TGF-β/Smad2/3 pathway. These findings suggest that EQ holds potential as a therapeutic agent for treating RA-ILD.
类风湿关节炎相关间质性肺病（RA-ILD）患者的特征为严重的肺纤维化和免疫失调。热休克蛋白90（HSP90）参与肺纤维化的进展和免疫反应。
本研究旨在探讨HSP90是否调控RA-ILD的发展及其潜在机制。
在体内，用博来霉素（BLM）处理胶原诱导的关节炎（CIA）小鼠，以建立肺纤维化的关节炎小鼠模型。在体外，使人肺成纤维细胞1（HLF1）暴露于转化生长因子β1（TGF-β1）以模拟RA-ILD模型。用HSP90抑制剂乙氧喹（EQ）处理RA-ILD模型，以探究HSP90在RA-ILD中的潜在机制。进行组织病理学分析并评估肺纤维化情况。评估M1/M2巨噬细胞和Th1/Th17/Treg细胞的分化。还探究了TGF-β/Smad2/3信号通路在EQ介导的RA-ILD进展中的作用。
在RA-ILD模型中HSP90α和HSP90β上调。乙氧喹减轻了BLM-CIA小鼠的关节炎，降低了α-平滑肌肌动蛋白（α-SMA）、I型胶原（Col-1）和纤连蛋白（FN）的表达以及羟脯氨酸含量，从而缓解了肺纤维化。此外，EQ增加了M1巨噬细胞以及诱导型一氧化氮合酶（iNOS）和肿瘤坏死因子α（TNF-α）水平；相反，EQ降低了M2巨噬细胞以及血管内皮生长因子（VEGF）-A和TGF-β1含量。它还降低了Th17（白细胞介素（IL）-17）水平，同时增加了Th1（干扰素γ（IFN-γ））和Treg（叉头框蛋白3（Foxp3））水平，并抑制了I型和II型转化生长因子β受体（TGF-βRI和TGF-βRII）的表达以及Smad2和Smad3的磷酸化。
本研究表明，EQ通过抑制HSP90调控肺纤维化和细胞免疫反应，其作用似乎是通过TGF-β/Smad2/3信号通路介导的。这些发现提示EQ有望成为治疗RA-ILD的药物。
