Wang Xiaotong, Zhang Di, Zhu Yaxue, Li Daojie, Shen Long, Wang Qiankun, Gao Yun, Li Xiaoping, Yu Mei
College of Animal Science and Technology, Center for Advanced Science in Animal Breeding and Health Breeding, Huazhong Agricultural University, Wuhan 430070, China.
College of Engineering, the Cooperative Innovation Center for Sustainable Pig Production, Huazhong Agricultural University, Wuhan 430070, China.
Sci Total Environ. 2024 Jan 15;908:168303. doi: 10.1016/j.scitotenv.2023.168303. Epub 2023 Nov 7.
Gaseous ammonia (NH), as a main air pollutant in pig farms and surrounding areas, directly affects animal and human health. The lung, as an important organ for gas exchange in the respiratory system, is damaged after NH exposure, but the underlying mechanism needs to be further explored. In this study, seven weeks old piglets were exposed to 50 ppm NH for 30 days, and displayed pulmonary fibrosis. Then, the toxicological mechanism of NH-induced pulmonary fibrosis was explored from the aspects of whole genome wide protein expression and post-translational modification. Totally, 404 differentially expressed proteins (DEPs) and 136 differentially lysine acetylated proteins (DAPs) were identified. The expression or lysine acetylation levels of proteins involved in mitochondrial energy metabolism including fatty acid oxidation (CPT1A, ACADVL, ACADS, HADHA, and HADHB), TCA cycle (IDH2 and MDH2), and oxidative phosphorylation (NDUFB7, NDUFV1, ATP5PB, ATP5F1A, COX5A, and COX5B) were significantly changed after NH exposure, which suggested that NH disrupted mitochondrial energy metabolism in the lung of piglets. Next, we found that type 2 alveolar epithelial cells (AEC2) damaged after NH exposure in vivo and in vitro. Integrin-linked kinase (ILK) was enriched in focal adhesion pathway, and showed significantly up-regulated acetylation levels at K191 (FC = 2.99) and K209 sites (FC = 1.52) after NH exposure. We illustrated that ILK-K191 hyper-acetylation inhibited AEC2 proliferation and induced AEC2 apoptosis by down-regulating pAKT-S473 in vitro. In conclusion, for the first time, our study revealed that protein acetylation played an important role in the process of NH-induced pulmonary fibrosis in piglets. Our findings provided valuable insights into toxicological harm of NH to human health.
气态氨（NH₃）作为猪场及其周边地区的主要空气污染物，直接影响动物和人类健康。肺作为呼吸系统中气体交换的重要器官，在接触NH₃后会受到损伤，但其潜在机制仍需进一步探索。在本研究中，7周龄仔猪暴露于50 ppm NH₃ 30天，出现了肺纤维化。然后，从全基因组蛋白质表达和翻译后修饰方面探讨了NH₃诱导肺纤维化的毒理学机制。共鉴定出404个差异表达蛋白（DEP）和136个差异赖氨酸乙酰化蛋白（DAP）。接触NH₃后，参与线粒体能量代谢的蛋白质，包括脂肪酸氧化（CPT1A、ACADVL、ACADS、HADHA和HADHB）、三羧酸循环（IDH2和MDH2）以及氧化磷酸化（NDUFB7、NDUFV1、ATP5PB、ATP5F1A、COX5A和COX5B）的表达或赖氨酸乙酰化水平发生了显著变化，这表明NH₃破坏了仔猪肺中的线粒体能量代谢。接下来，我们发现体内和体外接触NH₃后Ⅱ型肺泡上皮细胞（AEC2）受损。整合素连接激酶（ILK）在粘着斑通路中富集，接触NH₃后，其在K191（FC = 2.99）和K209位点（FC = 1.52）的乙酰化水平显著上调。我们证明，在体外，ILK-K191超乙酰化通过下调pAKT-S473抑制AEC2增殖并诱导AEC2凋亡。总之，我们的研究首次揭示了蛋白质乙酰化在NH₃诱导仔猪肺纤维化过程中起重要作用。我们的发现为NH₃对人类健康的毒理学危害提供了有价值的见解。
