Choline dehydrogenase interacts with SQSTM1 to activate mitophagy and promote coelomocyte survival in Apostichopus japonicus following Vibrio splendidus infection  

作　　者：Lian-Lian Sun Ying-Fen Dai Mei-Xiang You Cheng-Hua Li 

机构地区：[1]State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products,Ningbo University,Ningbo,Zhejiang 315211,China [2]Laboratory for Marine Fisheries Science and Food Production Processes,Qingdao National Laboratory for Marine Science and Technology,Qingdao,Shandong 266071,China

出　　处：《Zoological Research》2023年第5期905-918,共14页动物学研究（英文）

基　　金：supported by the National Natural Science Foundation of China (32102825);Natural Science Foundation of Zhejiang Province (LQ22C190003)。

摘　　要：Previous studies have shown that Vibrio splendidus infection causes mitochondrial damage in Apostichopus japonicus coelomocytes,leading to the production of excessive reactive oxygen species(ROS)and irreversible apoptotic cell death.Emerging evidence suggests that mitochondrial autophagy(mitophagy)is the most effective method for eliminating damaged mitochondria and ROS,with choline dehydrogenase(CHDH)identified as a novel mitophagy receptor that can recognize non-ubiquitin damage signals and microtubule-associated protein 1 light chain 3(LC3)in vertebrates.However,the functional role of CHDH in invertebrates is largely unknown.In this study,we observed a significant increase in the mRNA and protein expression levels of A.japonicus CHDH(AjCHDH)in response to V.splendidus infection and lipopolysaccharide(LPS)challenge,consistent with changes in mitophagy under the same conditions.Notably,AjCHDH was localized to the mitochondria rather than the cytosol following V.splendidus infection.Moreover,AjCHDH knockdown using si RNA transfection significantly reduced mitophagy levels,as observed through transmission electron microscopy and confocal microscopy.Further investigation into the molecular mechanisms underlying CHDH-regulated mitophagy showed that AjCHDH lacked an LC3-interacting region(LIR)for direct binding to LC3 but possessed a FB1 structural domain that binds to SQSTM1.The interaction between AjCHDH and SQSTM1 was further confirmed by immunoprecipitation analysis.Furthermore,laser confocal microscopy indicated that SQSTM1 and LC3 were recruited by AjCHDH in coelomocytes and HEK293T cells.In contrast,AjCHDH interference hindered SQSTM1 and LC3 recruitment to the mitochondria,a critical step in damaged mitochondrial degradation.Thus,AjCHDH interference led to a significant increase in both mitochondrial and intracellular ROS,followed by increased apoptosis and decreased coelomocyte survival.Collectively,these findings indicate that AjCHDH-mediated mitophagy plays a crucial role in coelomocyte survival in A.japon

关 键 词：Choline dehydrogenase MITOPHAGY SQSTM1 Microtubule-associated protein 1 light chain 3 Apostichopus japonicus 

分 类 号：S947.9[农业科学—水产养殖]