Hepatocyte SHP-1 is a Critical Modulator of Inflammation During Endotoxemia

Abstract

Abstract Liver hepatocytes (Hep) are known to be central players during the inflammatory response to systemic infection. Interestingly, the protein tyrosine phosphatases (PTP) SHP-1, has been recognized as a major regulator of inflammation; however their implication in the control of Hep-mediated inflammatory response is still unknown. To study its implication in the regulation of the Hep-mediated inflammatory response during endotoxemia, Cre-Lox mice with a Hep-specific Ptpn6 deletion (Ptpn6 H-KO ) were injected with LPS. In contrast to the wild-type mice (Ptpn6 f/f ) that started to die by 24 hrs post-inoculation, the Ptpn6 H-KO mice exhibited mortality by 6 hrs. In parallel, higher amounts of metabolic markers, pro-inflammatory mediators and circulating cytokines were detected in Ptpn6 H-KO mice. Primary Hep obtained from Ptpn6 H-KO , also showed increased secretion of pro-inflammatory cytokines and nitric oxide (NO) comparatively to its wild type (Ptpn6 f/f ) counterpart. Pharmacological approaches to block TNF-α and NO production protected both the Ptpn6 f/f and the Ptpn6 H-KO mice against deadly LPS-mediated endotoxemia. Collectively, these results establish hepatocyte SHP-1 is a critical player regulating systemic inflammation. Our findings further suggest that SHP-1 activation could represent a new therapeutic avenue to better control inflammatory-related pathologies.