PPARγ alleviated hepatocyte steatosis through reducing SOCS3 by inhibiting JAK2/STAT3 pathway

Peroxisome proliferator-activated receptor gamma (PPAR gamma) participates in the process of insulin resistance (IR), a crucial pathophysiology in non-alcoholic fatty liver disease (NAFLD). Meanwhile, suppressor of cytokine signaling3 (SOCS3) also regulates IR in NAFLD. Both PPAR gamma and SOCS3 play a role in NAFLD through regulating IR, while it is unclear whether these two proteins interact to regulate hepatic steatosis. PPARy, SOCS3 and its associated JAK2/STAT3 pathway were analyzed using Kuppfer cells (KCs) treatment with LPS and BRL-3A cells treatment with palmitic acid, KC-conditioned medium (KCCM), PPARy agonist rosiglitazone (ROZ) or JAK2 inhibitor AG490 to demonstrate the role of PPARy and SOCS3 in hepatocytes steatosis. As LPS concentration increasing, phagocytosis activity of KCs decreased; but releasing of TNF-alpha and IL-6 increased. After treatment with KCCM, mRNA level of SOCS3, JAK2 and STAT3 as well as protein expression of SOCS3, p-JAK2 and p-STAT3 in steatosis BRL-3A cells increased significantly, which were inhibited by AG490 or ROZ treatment. Taken together, these results indicated that KCCM attributed to KCs dysfunction facilitated hepatocyte steatosis through promoting expressing SOCS3; but PPARy agonist ROZ alleviated steatosis through reducing SOCS3 expression by inhibiting JAK2/STAT3 in hepatocytes. (C) 2018 Elsevier Inc. All rights reserved.