Spred2 Deficiency Exacerbates D-Galactosamine/Lipopolysaccharide -induced Acute Liver Injury in Mice via Increased Production of TNF?.
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ABSTRACT: Acute liver injury (ALI) is characterized by hepatocyte damage and inflammation. In the present study, we examined whether the absence of Sprouty-related EVH1-domain-containing protein 2 (Spred2), a negative regulator of the Ras/Raf/ERK/MAPK pathway, influences ALI induced by D-galactosamine (D-GalN) and lipopolysaccharide (LPS). Compared to wild-type mice, Spred2-/- mice developed exacerbated liver injury represented by enhanced hepatocyte damage and inflammation. Enhanced ERK activation was observed in Spred2-/--livers, and the MEK/ERK inhibitor U0126 ameliorated ALI. Hepatic tumour necrosis factor ? (TNF?) and interleukin (IL)-1? levels were increased in Spred-2-/--livers, and the neutralization of TNF? dramatically ameliorated ALI, which was associated with decreased levels of endogenous TNF? and IL-1?. When mice were challenged with D-GalN and TNF?, much severer ALI was observed in Spred2-/- mice with significant increases in endogenous TNF? and IL-1? in the livers. Immunohistochemically, Kupffer cells were found to produce TNF?, and isolated Kupffer cells from Spred2-/- mice produced significantly higher levels of TNF? than those from wild-type mice after LPS stimulation, which was significantly decreased by U0126. These results suggest that Spred2 negatively regulates D-GalN/LPS-induced ALI under the control of TNF? in Kupffer cells. Spred2 may present a therapeutic target for the treatment of ALI.
SUBMITTER: Yang X
PROVIDER: S-EPMC5760641 | biostudies-literature | 2018 Jan
REPOSITORIES: biostudies-literature
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