Hepatocytes produce TNF-α following hypoxia-reoxygenation and liver ischemia-reperfusion in a NADPH oxidase- and c-Src-dependent manner.

Abstract

Cell line studies have previously demonstrated that hypoxia-reoxygenation (H/R) leads to the production of NADPH oxidase 1 and 2 (NOX1 and NOX2)-dependent reactive oxygen species (ROS) required for the activation of c-Src and NF-κB. We now extend these studies into mouse models to evaluate the contribution of hepatocytes to the NOX- and c-Src-dependent TNF-α production that follows H/R in primary hepatocytes and liver ischemia-reperfusion (I/R). In vitro, c-Src-deficient primary hepatocytes produced less ROS and TNF-α following H/R compared with controls. In vivo, c-Src-KO mice also had impaired TNF-α and NF-κB responses following partial lobar liver I/R. Studies in NOX1 and p47phox knockout primary hepatocytes demonstrated that both NOX1 and p47phox are partially required for H/R-mediated TNF-α production. To further investigate the involvement of NADPH oxidases in the production of TNF-α following liver I/R, we performed additional in vivo experiments in knockout mice deficient for NOX1, NOX2, p47phox, Rac1, and/or Rac2. Cumulatively, these results demonstrate that NOX2 and its activator subunits (p47phox and Rac) control the secretion of TNF-α by the liver following I/R. Interestingly, in the absence of Kupffer cells and NOX2, NOX1 played a dominant role in TNF-α production following hepatic I/R. However, NOX1 deletion alone had little effect on I/R-induced TNF-α. Thus Kupffer cell-derived factors and NOX2 act to suppress hepatic NOX1-dependent TNF-α production. We conclude that c-Src and NADPH oxidase components are necessary for redox-mediated production of TNF-α following liver I/R and that hepatocytes play an important role in this process.

• Authors: Netanya Y Spencer, Weihong Zhou, Qiang Li, Yulong Zhang, Meihui Luo, Ziying Yan, Thomas J Lynch, Duane Abbott, Botond Banfi, John F Engelhardt
• Journal: American journal of physiology. Gastrointestinal and liver physiology (Am J Physiol Gastrointest Liver Physiol) Vol. 305 Issue 1 Pg. G84-94 (Jul 01 2013) ISSN: 1522-1547 [Electronic] United States
• PMID: 23639811 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• NF-kappa B
• Reactive Oxygen Species
• Tumor Necrosis Factor-alpha
• Gadolinium
• NADPH Oxidases
• CSK Tyrosine-Protein Kinase
• src-Family Kinases
• gadolinium chloride

Topics

• Animals
• Blotting, Western
• CSK Tyrosine-Protein Kinase
• Gadolinium
• Gene Expression Regulation, Enzymologic (physiology)
• Hepatocytes (metabolism)
• Liver (blood supply, metabolism, pathology)
• Mice
• Mice, Knockout
• NADPH Oxidases (genetics, metabolism)
• NF-kappa B (genetics, metabolism)
• Reactive Oxygen Species (metabolism)
• Reperfusion Injury (metabolism)
• Tumor Necrosis Factor-alpha (genetics, metabolism)
• src-Family Kinases (genetics, metabolism)