Frontiers in Molecular Immunology

Heat stress induces suppressor of cytokine signaling (SOCS) 1 and SOCS2 expression in the intestinal gut and disrupts inflammatory cytokine production in pigs. These changes may be important to the development of inflammatory bowel disease in heat-stressed pigs. However, the underlying mechanisms have not yet been completely elucidated. In the present study, we examined the roles of SOCS1 and SOCS2 in regulating the nuclear factor (NF)-κB pathway in CRL-2845 porcine macrophages. Ectopic expression of HSP70 significantly modulated NF-κB activity (p ≤ 0.05). Moreover, co-expression of SOCS1 or SOCS2 with HSP70 reduced NF-κB activity, which was abolished by SOCS1 or SOCS2 knockdown with  small interfering RNA. Additionally, myeloid differentiation factor 88 (MyD88)-adaptor-like (Mal) protein was down-regulated in cells expressing SOCS1 and SOCS2. SOCS1 and SOCS2 were found to negatively regulate the activity of NF-κB induced by HSP70 overexpression by degrading Mal. These findings may facilitate the development of novel SOCS1-based and SOCS2-based therapeutic strategies for controlling heat stress-related disorders in pigs.