Research
| Title： | TLRs signaling pathway regulation, antibacterial and apoptotic activity of largemouth bass ECSIT during Edwardsiella piscicida infection |
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| First author： | Pi, Xiangyu; Yan, Dong; Xu, Yang; Pan, Mingzhu; Wang, Zisheng; Chang, Mingxian; Qi, Zhitao |
| Journal： | AQUACULTURE |
| Years： | 2025 |
| DOI： | 10.1016/j.aquaculture.2024.741615 |
| Abstract： | Evolutionary conserved signaling intermediate in Toll pathways (ECSIT) was a pleiotropic molecule with roles in inflammation, embryonic development and mitochondrial function. In the present study, the ECSIT gene was identified from largemouth bass (Micropterus salmoides), and its functions during Edwardsiella piscicida infection were analyzed. Largemouth bass ECSIT shared high sequence identities (60.3 % similar to 90.1 %) with ECSIT of other fish species. Also, two important protein domains (the ECSIT domain and C-terminal domain) that conserved exist in other vertebrates' ECSIT were found in largemouth bass ECSIT. Largemouth bass ECSIT was ubiquitously expressed in all selected tissues and could be up-regulated in spleen after E. piscidia infection. Several toll-like receptors (TLRs) signaling related genes, including MyD88, tumor necrosis factor receptor-associated factor 6 (TRAF6), transforming-growth factor-beta-activated kinase-1 (TAK1), NF-kappa B and P65, could be induced by largemouth bass ECSIT in Epithelioma papulosum cyprini (EPC) cells or EPC cells infected with E. piscidia. And, largemouth bass ECSIT could interact with TRAF6 that was confirmed by co-IP assay and molecular docking analysis. In addition, overexpression of ECSIT could significantly suppress the intracellular proliferation of E. piscicida. Further, largemouth bass ECSIT could induce the apoptosis of EPC cells following E. piscicida infection and up-regulate several apoptosis-related genes, including p53, B-cell lymphoma-2 associated X (Bax), programmed cell death 8 (PDCD8), baculoviral IAP repeat-containing 5 (BIRC5), caspase9 and caspase3. Our results demonstrated that largemouth bass ECSIT had activities of regulation of TLRs signaling pathway, antibacterial, and apoptotic inducing in response to E. piscicida infection. To the best of our knowledge, this is the first report on ECSIT of largemouth bass and first research about the relationship between fish ECSIT and apoptosis. Our study further enriched the functions of ECSIT and provided foundation of in-depth understanding the antibacterial immune mechanisms in fish. |
