Rheumatology and Immunology Department, Jiujiang City Key Laboratory of Cell Therapy, The First Hospital of Jiujiang City, 332000 Jiujiang, Jiangxi, China.
Discov Med. 2024 Nov;36(190):2274-2286. doi: 10.24976/Discov.Med.202436190.209.
Pulmonary fibrosis is a severe respiratory condition marked by the formation of scar tissue in the lungs, which makes it distinguishable from atypical fibrosis. The specific mechanisms of angiotensin-converting enzyme 2 (ACE2) in pulmonary fibrosis are still unclear, although it has been demonstrated to have a significant role in this condition. The objective of this study was to examine the impact of ACE2 on lung fibrosis.
Both and experimental approaches were employed in this study to evaluate the function of ACE2. In the experiments, an animal model of pulmonary fibrosis was established by injecting 0.1 mL of bleomycin solution into C57BL/6 male mice, and the effects of ACE2 overexpression on pulmonary fibrosis were observed, for the animal group overexpressing ACE2 (Model+ACE2 group), treatments with SB505124 (transforming growth factor-β type I receptor (TGF-βRI) (ALK5) inhibitor) and XAV939 (Wnt Family Member 3a (Wnt3a) inhibitor) were administered, to evaluate the effects of these pathway inhibitors on ACE2 overexpression in the treatment of pulmonary fibrosis. Lung tissue samples were collected from the animals and subjected to pathological examination (hematoxylin and eosin (HE) and Masson's trichrome staining) to assess the degree of pathological inflammation and fibrosis. Concurrently, the expression levels of proteins and genes related to the ACE2, Wnt/glycogen synthase kinase (GSK)-3β/β-catenin, and TGF-β1/Smad2 signaling pathways were measured using Western blotting and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) techniques. In the experiments, pulmonary fibrosis was simulated in human lung fibroblasts (HLFs), which were stimulated with TGF-β1. The correlation of ACE2 overexpression to attenuate pulmonary fibrosis with Wnt/GSK-3β/β-catenin and TGF-β1/Smad2 signaling pathways was explored.
The ACE2 overexpression could effectively reduce pulmonary fibrosis and inflammation in mice and HLFs by modulating signaling pathways ( < 0.01). In mice, ACE2 reduced inflammation and collagen accumulation, decreasing levels of α-smooth muscle actin (α-SMA) and fibronectin ( < 0.01). Compared to the Model+ACE2 group, the Model+ACE2+SB505124 underwent a greater reduction in inflammation and fibrosis, as well as decreased levels of α-SMA and fibronectin ( < 0.05). Overexpression of ACE2, XAV939, and SB505124 all significantly reduced the expression levels of Wnt3a, β-catenin, p-GSK-3β, TGF-β1, and p-Smad2 proteins in mice with pulmonary fibrosis ( < 0.05). In HLFs, ACE2 counteracted TGF-β1 effects, reducing cell proliferation and levels of fibrosis markers such as collagen, α-SMA and fibronectin ( < 0.01). It also inhibited the TGF-β1-induced epithelial-mesenchymal transition (EMT), showcasing its therapeutic potential against lung fibrosis and inflammation by regulating key signaling pathways and EMT processes ( < 0.01).
The desirable effects of ACE2 in alleviating pulmonary fibrosis are associated with the regulation of the Wnt/GSK-3β/β-catenin and TGF-β1/Smad2 signaling pathway. These results offer significant evidence for further investigation into the potential use of ACE2 in treating pulmonary fibrosis and provide new avenues for the advancement of innovative therapeutic approaches.
肺纤维化是一种严重的呼吸系统疾病，其特征是肺部形成疤痕组织，这使其与非典型纤维化区别开来。血管紧张素转换酶 2（ACE2）在肺纤维化中的具体机制尚不清楚，但已证明它在这种疾病中具有重要作用。本研究旨在研究 ACE2 对肺纤维化的影响。
本研究采用 和 实验方法来评估 ACE2 的功能。在 实验中，通过向 C57BL/6 雄性小鼠注射 0.1ml 博来霉素溶液建立肺纤维化动物模型，观察 ACE2 过表达对肺纤维化的影响，对于过表达 ACE2 的动物组（模型+ACE2 组），给予 SB505124（转化生长因子-β型 I 受体（TGF-βRI）（ALK5）抑制剂）和 XAV939（Wnt 家族成员 3a（Wnt3a）抑制剂）治疗，以评估这些途径抑制剂对 ACE2 过表达治疗肺纤维化的影响。从动物中收集肺组织样本进行病理检查（苏木精和伊红（HE）和 Masson 三色染色），以评估病理炎症和纤维化的程度。同时，使用 Western blot 和定量逆转录聚合酶链反应（qRT-PCR）技术测量与 ACE2、Wnt/糖原合酶激酶（GSK）-3β/β-连环蛋白和 TGF-β1/Smad2 信号通路相关的蛋白和基因的表达水平。在 实验中，通过用 TGF-β1 刺激人肺成纤维细胞（HLFs）来模拟肺纤维化。探讨 ACE2 过表达通过 Wnt/GSK-3β/β-catenin 和 TGF-β1/Smad2 信号通路减轻肺纤维化的相关性。
ACE2 过表达可通过调节信号通路有效减轻小鼠和 HLFs 中的肺纤维化和炎症（<0.01）。在小鼠中，ACE2 减少炎症和胶原蛋白积累，降低α-平滑肌肌动蛋白（α-SMA）和纤维连接蛋白的水平（<0.01）。与模型+ACE2 组相比，模型+ACE2+SB505124 组的炎症和纤维化减轻更明显，α-SMA 和纤维连接蛋白的水平也降低（<0.05）。ACE2、XAV939 和 SB505124 的过表达均显著降低了肺纤维化小鼠中 Wnt3a、β-连环蛋白、p-GSK-3β、TGF-β1 和 p-Smad2 蛋白的表达水平（<0.05）。在 HLFs 中，ACE2 拮抗 TGF-β1 的作用，降低细胞增殖和纤维化标志物如胶原蛋白、α-SMA 和纤维连接蛋白的水平（<0.01）。它还抑制 TGF-β1 诱导的上皮-间充质转化（EMT），通过调节关键信号通路和 EMT 过程，展示了其在治疗肺纤维化和炎症方面的治疗潜力（<0.01）。
ACE2 缓解肺纤维化的理想效果与 Wnt/GSK-3β/β-catenin 和 TGF-β1/Smad2 信号通路的调节有关。这些结果为进一步研究 ACE2 在治疗肺纤维化中的潜在用途提供了重要证据，并为创新治疗方法的发展提供了新途径。
