Hepatic SH2B1 and SH2B2 regulate liver lipid metabolism and VLDL secretion in mice

PLoS One. 2013 Dec 17;8(12):e83269. doi: 10.1371/journal.pone.0083269. eCollection 2013.

Abstract

SH2B1 is an SH2 and PH domain-containing adaptor protein. Genetic deletion of SH2B1 results in obesity, type 2 diabetes, and fatty liver diseases in mice. Mutations in SH2B1 are linked to obesity in humans. SH2B1 in the brain controls energy balance and body weight at least in part by enhancing leptin sensitivity in the hypothalamus. SH2B1 in peripheral tissues also regulates glucose and lipid metabolism, presumably by enhancing insulin sensitivity in peripheral metabolically-active tissues. However, the function of SH2B1 in individual peripheral tissues is unknown. Here we generated and metabolically characterized hepatocyte-specific SH2B1 knockout (HKO) mice. Blood glucose and plasma insulin levels, glucose tolerance, and insulin tolerance were similar between HKO, albumin-Cre, and SH2B1(f/f) mice fed either a normal chow diet or a high fat diet (HFD). Adult-onset deletion of SH2B1 in the liver either alone or in combination with whole body SH2B2 knockout also did not exacerbate HFD-induced insulin resistance and glucose intolerance. Adult-onset, but not embryonic, deletion of SH2B1 in the liver attenuated HFD-induced hepatic steatosis. In agreement, adult-onset deletion of hepatic SH2B1 decreased the expression of diacylglycerol acyltransferase-2 (DGAT2) and increased the expression of adipose triglyceride lipase (ATGL). Furthermore, deletion of liver SH2B1 in SH2B2 null mice attenuated very low-density lipoprotein (VLDL) secretion. These data indicate that hepatic SH2B1 is not required for the maintenance of normal insulin sensitivity and glucose metabolism; however, it regulates liver triacylglycerol synthesis, lipolysis, and VLDL secretion.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adaptor Proteins, Signal Transducing / physiology*
  • Animals
  • Diet, High-Fat
  • Fatty Liver / genetics
  • Fatty Liver / metabolism
  • Glucose Intolerance / genetics
  • Insulin Resistance / genetics
  • Lipid Metabolism / genetics*
  • Lipoproteins, VLDL / metabolism*
  • Liver / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout

Substances

  • Adaptor Proteins, Signal Transducing
  • Lipoproteins, VLDL
  • Sh2b2 protein, mouse
  • Sh2bpsm1 protein, mouse