Probiotic components of Bacillus siamensis LF4 mitigated β-conglycinin caused cell injury via modulating TLR2/MAPKs/NF-κB signaling in Lateolabrax maculatus

Zi-Yan Liu; Hong-Ling Yang; Sha Li; Guo-He Cai; Ji-Dan Ye; Chun-Xiao Zhang; Yun-Zhang Sun

doi:10.1016/j.fsi.2023.109010

Probiotic components of Bacillus siamensis LF4 mitigated β-conglycinin caused cell injury via modulating TLR2/MAPKs/NF-κB signaling in Lateolabrax maculatus

Fish Shellfish Immunol. 2023 Oct:141:109010. doi: 10.1016/j.fsi.2023.109010. Epub 2023 Aug 19.

Authors

Zi-Yan Liu¹, Hong-Ling Yang², Sha Li¹, Guo-He Cai², Ji-Dan Ye², Chun-Xiao Zhang², Yun-Zhang Sun³

Affiliations

¹ The Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen, 361021, China.
² The Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen, 361021, China; Xiamen Key Laboratory for Feed Quality Testing and Safety Evaluation, Fisheries College, Jimei University, Xiamen, 361021, China.
³ The Key Laboratory of Healthy Mariculture for the East China Sea, Ministry of Agriculture, Fisheries College, Jimei University, Xiamen, 361021, China; Xiamen Key Laboratory for Feed Quality Testing and Safety Evaluation, Fisheries College, Jimei University, Xiamen, 361021, China; Engineering Research Center of the Modern Technology for Eel Industry, Ministry of Education, Xiamen, 361021, China. Electronic address: jmusunyunzhang@163.com.

PMID: 37598736
DOI: 10.1016/j.fsi.2023.109010

Abstract

β-conglycinin is a recognized factor in leading to intestinal inflammation and limiting application of soybean meal in aquaculture. Our previous study reported that heat-killed B. siamensis LF4 could effectively mitigate inflammatory response and apoptosis caused by β-conglycinin in spotted seabass (Lateolabrax maculatus) enterocytes, but the mechanisms involved are not fully understood. In the present study, therefore, whole cell wall (CW), peptidoglycan (PG) and lipoteichoic acid (LTA) and cell-free supernatant (CFS) have been collected from B. siamensis LF4 and their mitigative function on β-conglycinin-induced adverse impacts and mechanisms underlying were evaluated. The results showed that β-conglycinin-induced cell injury, characterized with significantly decreased cell viability and increased activities of lactate dehydrogenase, glutamic oxaloacetic transaminase, glutamic propylic transaminase (P < 0.05), were reversed by subsequent heat-killed B. siamensis LF4 and its CW, LTA, PG and CFS treatment. Enterocytes co-cultured with heat-killed B. siamensis LF4 and its CW, LTA, PG and CFS (especially PG) significantly increased expressions of anti-inflammatory genes (IL-2, IL-4, IL-10 and TGF-β1), tight junction proteins (ZO-1, occludin and claudin-b) and antimicrobial peptides (β-defensin, hepcidin-1, NK-lysin and piscidin-5), and decreased expressions of pro-inflammatory genes (IL-1β, IL-8 and TNF-α) and apoptosis-related genes (caspase 3, caspase 8 and caspase 9) (P < 0.05), indicating their excellent mitigation effects on β-conglycinin-induced cell damages. In addition, heat-killed B. siamensis LF4 and its CW, LTA, PG and CFS significantly increased TLR2 mRNA level (especially in PG treatment), and decreased MAPKs (JNK, ERK, p38 and AP-1) and NF-κB related genes expressions. In conclusion, heat-killed B. siamensis LF4 and its CW, LTA, PG and CFS could modulating TLR2/MAPKs/NF-κB signaling and alleviating β-conglycinin-induced enterocytes injury in spotted seabass (L. maculatus), and PG presented the best potential.

Keywords: Apoptosis; Bacillus siamensis; Enterocytes; Inflammation; Lateolabrax maculatus; TLR2/MAPKs/NF-κB signaling; β-conglycinin.