Suppressor of cytokine signaling 3 (SOCS3) is related to pro-inflammatory cytokine production and triglyceride deposition in turbot (Scophthalmus maximus)

Tan, Peng [Ocean University of China] Peng, Mo [Ocean University of China] Liu, Dongwu [Ocean University of China] Guo, Huarong [Ocean University of China] Mai, Kangsen [Qingdao National Laboratory for Marine Science and Technology] Nian, Rui [Ocean University of China] Macq, Benoît [UCL] Ai, Qinghui [Ocean University of China] et al.[show all]

Turbot (Scophthalmus maximus) is an economically important fish that is farmed by aquaculture for human consumption. Aquacultured turbot are commonly fed a high-lipid diet; however, this diet causes excessive lipid deposition and the overexpression of pro-inflammatory cytokines. Studies in mammals have indicated that a relationship exists between pro-inflammatory cytokine overexpression and altered lipid metabolism through the activation of suppressor of cytokine signaling 3 (SOCS3). In this study, we investigated the relationship between SOCS3 and triglyceride (TG) deposition and mechanism of SOCS3 activation in farmed turbot fed high-lipid diet (HLD). TG content increased with SOCS3 production, mediated by toll-like receptor-nuclear transcription factor kappa-B (TLR-NFκB) signaling in the liver of turbot fed a HLD and in turbot primary liver cells incubated with oleic acid (OA). Overexpression of SOCS3 increased TG deposition via the increased production of mature sterol regulatory element binding protein 1 (m-SREBP-1). Knockdown of SOCS3 in turbot primary liver cells resulted in normalized TG deposition and decreased m-SREBP-1 production. These results suggest that the HLD and OA can induce cytokine expression by activating the TLR-NFκB signaling pathways, resulting in increased SOCS3 expression. It is proposed that SOCS3 enhances m-SREBP-1 production, leading to TG deposition. These findings provide important new insights into the relationship between cytokine expression and TG deposition and mechanism of HLD-induced pro-inflammatory response, which could help to improve the health of farmed turbot and a better understanding of fish immunity.