Tang Xiaofang, Wei Wei, Sun Yuqing, Weaver Timothy E, Nakayasu Ernesto S, Clair Geremy, Snowball John M, Na Cheng-Lun, Apsley Karen S, Martin Emily P, Kotton Darrell N, Alysandratos Konstantinos-Dionysios, Huo Jiuzhou, Molkentin Jeffery D, Gower William A, Lin Xinhua, Whitsett Jeffrey A
State Key Laboratory of Genetic Engineering, Greater Bay Area Institute of Precision Medicine (Guangzhou), School of Life Sciences, Shanghai Key Laboratory of Lung Inflammation and Injury, Zhongshan Hospital, Fudan University, Shanghai, China .
Perinatal Institute, Divisions of Neonatology, Perinatal and Pulmonary Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, USA.
J Clin Invest. 2024 Oct 15;134(23):e173861. doi: 10.1172/JCI173861.
The most common mutation in surfactant protein C gene (SFTPC), SFTPCI73T, causes interstitial lung disease with few therapeutic options. We previously demonstrated that EMC3, an important component of the multiprotein endoplasmic reticulum membrane complex (EMC), is required for surfactant homeostasis in alveolar type 2 epithelial (AT2) cells at birth. In the present study, we investigated the role of EMC3 in the control of SFTPCI73T metabolism and its associated alveolar dysfunction. Using a knock-in mouse model phenocopying the I73T mutation, we demonstrated that conditional deletion of Emc3 in AT2 cells rescued alveolar remodeling/simplification defects in neonatal and adult mice. Proteomic analysis revealed that Emc3 depletion reversed the disruption of vesicle trafficking pathways and rescued the mitochondrial dysfunction associated with I73T mutation. Affinity purification-mass spectrometry analysis identified potential EMC3 interacting proteins in lung AT2 cells, including valosin containing protein (VCP) and its interactors. Treatment of SftpcI73T knock-in mice and SFTPCI73T-expressing iAT2 cells derived from SFTPCI73T patient-specific iPSCs with the VCP inhibitor CB5083 restored alveolar structure and SFTPCI73T trafficking, respectively. Taken together, the present work identifies the EMC complex and VCP in the metabolism of the disease-associated SFTPCI73T mutant, providing therapeutical targets for SFTPCI73T-associated interstitial lung disease.
表面活性蛋白C基因（SFTPC）最常见的突变，即SFTPCI73T，会导致间质性肺病，且治疗选择有限。我们之前证明，内质网多蛋白膜复合物（EMC）的重要组成部分EMC3是出生时肺泡II型上皮（AT2）细胞表面活性物质稳态所必需的。在本研究中，我们调查了EMC3在控制SFTPCI73T代谢及其相关肺泡功能障碍中的作用。使用模拟I73T突变的基因敲入小鼠模型，我们证明在AT2细胞中条件性敲除Emc3可挽救新生和成年小鼠的肺泡重塑/简化缺陷。蛋白质组学分析表明，Emc3缺失可逆转囊泡运输途径的破坏，并挽救与I73T突变相关的线粒体功能障碍。亲和纯化-质谱分析确定了肺AT2细胞中潜在的EMC3相互作用蛋白，包括含缬酪肽蛋白（VCP）及其相互作用分子。用VCP抑制剂CB5083处理SftpcI73T基因敲入小鼠和源自SFTPCI73T患者特异性诱导多能干细胞的表达SFTPCI73T的iAT2细胞，分别恢复了肺泡结构和SFTPCI73T的运输。综上所述，本研究确定了EMC复合物和VCP在疾病相关的SFTPCI73T突变体代谢中的作用，为SFTPCI73T相关的间质性肺病提供了治疗靶点。
