Small Heterodimer Partner Deficiency Increases Inflammatory Liver Injury Through C-X-C motif chemokine ligand 2-Driven Neutrophil Recruitment in Mice.
Although detailed pathophysiological mechanisms of fulminant hepatitis remain elusive, immune cell recruitment with excessive cytokine production is a well-recognized hallmark of the disease. We determined the function of orphan nuclear receptor small heterodimer partner (SHP) in concanavalin A (ConA)-induced hepatitis model. Male C57BL/6 J mice were injected intravenously with either a lethal dose (25 mg/kg) or a sub-lethal dose (15 mg/kg) of ConA. For the C-X-C motif chemokine ligand (CXCL) 2 neutralization study, mice were intravenously administered anti-mouse CXCL2 antibody (100 μg/mouse). Thirty-six hours following lethal dose of ConA administration, 47% wild type (WT) mice were alive, whereas >85% of Shp knockout (KO) were dead. Shp KO mice were highly susceptible to ConA-induced liver injury and exhibited increased liver necrosis upon sub-lethal dose of ConA administration. FACS analysis and immunohistochemical staining showed significantly higher neutrophil infiltration in Shp KO mice, as compared with WT mice. We found that also in the WT situation, Shp expression gradually decreased, while Cxcl2 expression increased until 6 h, and vice versa at 24 h upon ConA-treatment, indicating an inverse correlation between Shp and Cxcl2 expression during ConA-induced hepatitis. Furthermore, in vivo neutralization of CXCL2 with neutralizing antibody reduces ConA-induced plasma ALT and AST levels, hepatocyte death and neutrophil infiltration in Shp KO mice. Collectively, these results confirm that lacking of SHP results in CXCL2-dependent neutrophil infiltration in ConA-induced liver damage. SHP plays a protective, anti-inflammatory role in liver during acute liver inflammation.