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Cytosolic phospholipase A(2)? protects against Fas- but not LPS-induced liver injury.

ABSTRACT: Cytosolic phospholipase A(2)? (cPLA(2)?) is a rate-limiting key enzyme controlling the release of arachidonic acid (AA) substrate for the synthesis of prostaglandins and leukotrienes. This study was designed to explore the role of hepatocyte cPLA(2)? in Fas-mediated liver injury, in vivo.Transgenic mice with targeted expression of cPLA(2)? under control of the albumin-promoter enhancer and wild-type mice were injected intraperitoneally with anti-Fas antibody Jo2 or lipopolysaccharide plus d-galactosamine and monitored for liver injury and survival at various time points.The cPLA(2)? Tg mice resist Fas-induced liver failure, as reflected by the lower serum transaminase levels, fewer apoptotic hepatocytes, reduced caspase activation, and reduced PARP cleavage when compared to the matched wild type mice. Inhibition of cPLA(2)? by its pharmacological inhibitor, pyrrolidine, enhanced Jo2-induced liver injury in both cPLA(2)? Tg and wild type mice. Hepatic overexpression of cPLA(2)? increases the expression of EGFR in the liver and the EGFR inhibitor, AG1478, exacerbated Jo2-mediated liver injury. The cPLA(2)? transgenic mice develop more prominent liver tissue damage than wild-type mice after LPS/d-galactosamine injection.Hepatocyte cPLA(2)? protects against Fas-induced liver injury and this effect is mediated at least in part through the upregulation of EGFR.

SUBMITTER: Li G

PROVIDER: S-EPMC3221788 | biostudies-other | 2011 Dec

REPOSITORIES: biostudies-other

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Cytosolic phospholipase A(2)α protects against Fas- but not LPS-induced liver injury.

Li Guiying G Chen Weina W Han Chang C Wu Tong T

Journal of hepatology 20110414 6

<h4>Background & aims</h4>Cytosolic phospholipase A(2)α (cPLA(2)α) is a rate-limiting key enzyme controlling the release of arachidonic acid (AA) substrate for the synthesis of prostaglandins and leukotrienes. This study was designed to explore the role of hepatocyte cPLA(2)α in Fas-mediated liver injury, in vivo.<h4>Methods</h4>Transgenic mice with targeted expression of cPLA(2)α under control of the albumin-promoter enhancer and wild-type mice were injected intraperitoneally with anti-Fas anti ...[more]

PMID: 21703211

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Project description:Acetaminophen (APAP) overdose is the primary cause of drug‑induced acute liver failure in numerous Western countries. NLR family pyrin domain containing 3 (NLRP3) inflammasome activation serves a pivotal role in the pathogenesis of various forms of acute liver injury. However, the cellular source for NLRP3 induction and its involvement during APAP‑induced hepatotoxicity have not been thoroughly investigated. In the present study, hematoxylin and eosin staining was performed to assess histopathological changes of liver tissue. Immunohistochemistry staining(NLRP3, Caspase‑1, IL‑1β, GSDMD and Caspase‑3), western blotting (NLRP3, Caspase‑1, IL‑1β, GSDMD and Caspase‑3) and RT‑qPCR (NLRP3, Caspase‑1 and IL‑1β) were performed to assess the expression of NLRP3/GSDMD signaling pathway. TUNEL staining was performed to assess apoptosis of liver tissue. The serum expression levels of inflammatory factors (IL‑6, IL‑18, IL‑1β and TNF‑α) were assessed using ELISA and inflammation of liver tissue was assessed using immunohistochemistry (Ly6G and CD68) and RT‑qPCR (TNF‑α, Il‑6, Mcp‑1, Cxcl‑1, Cxcl‑2). A Cell Counting Kit‑8 was performed to assess cell viability and apoptosis. Protein and gene expression were analyzed by western blotting (PCNA, CCND1) and RT‑qPCR (CyclinA2, CyclinD1 and CyclinE1). Through investigation of an APAP‑induced acute liver injury model (AILI), the present study demonstrated that APAP overdose induced activation of NLRP3 and cleavage of gasdermin D (GSDMD) in hepatocytes, both in vivo and in vitro. Additionally, mice with hepatocyte‑specific knockout of Nlrp3 exhibited reduced liver injury and lower mortality following APAP intervention, accompanied by decreased infiltration of inflammatory cells and attenuated inflammatory response. Furthermore, pharmacological blockade of NLRP3/GSDMD signaling using MCC950 or disulfiram significantly ameliorated liver injury and reduced hepatocyte death. Notably, hepatocyte Nlrp3 deficiency promoted liver recovery by enhancing hepatocyte proliferation. Collectively, the present study demonstrated that inhibition of the NLRP3 inflammasome protects against APAP‑induced acute liver injury by reducing hepatocyte pyroptosis and suggests that targeting NLRP3 may hold therapeutic potential for treating AILI.

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Cytosolic phospholipase A(2)? protects against Fas- but not LPS-induced liver injury.

Publications

Cytosolic phospholipase A(2)α protects against Fas- but not LPS-induced liver injury.

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