Williams 2015 J Biol Chem
Williams AS, Kang L, Zheng J, Grueter CA, Bracy DP, James FD, Pozzi A, Wasserman DH (2015) Integrin Ξ±1-null mice exhibit improved fatty liver when fed a high fat diet despite severe hepatic insulin resistance. J Biol Chem 290:6546-57. |
Williams AS, Kang L, Zheng J, Grueter CA, Bracy DP, James FD, Pozzi A, Wasserman DH (2015) J Biol Chem
Abstract: Hepatic insulin resistance is associated with increased collagen. Integrin Ξ±1Ξ²1 is a collagen binding receptor expressed on hepatocytes. Here we show that expression of the Ξ±1 subunit is increased in hepatocytes isolated from high fat fed (HF-fed) mice. To determine whether the integrin Ξ±1 subunit protects against impairments in hepatic glucose metabolism, we analyzed glucose tolerance and insulin sensitivity in HF-fed integrin Ξ±1-null (itgΞ±1-/-) and wild-type littermates (itgΞ±1+/+). Using the insulin clamp, we found that insulin-stimulated hepatic glucose production was suppressed by ~50% in HF-fed itgΞ±1+/+ mice. In contrast, it was not suppressed in HF-fed itgΞ±1-/- mice indicating severe hepatic insulin resistance. This was associated with decreased hepatic insulin signaling in HF-fed itgΞ±1-/- mice. Interestingly, hepatic triglyceride and diglyceride content were normalized to chow-fed levels in HF-fed itgΞ±1-/- mice. This indicates that hepatic steatosis is dissociated from insulin resistance in HF-fed itgΞ±1-/- mice. The decrease in hepatic lipid accumulation in HF-fed itgΞ±1-/- mice was associated with altered free fatty acid metabolism. These studies establish a role for integrin signaling in facilitating hepatic insulin action, while promoting lipid accumulation in mice challenged with a HF diet.
Copyright Β© 2015, The American Society for Biochemistry and Molecular Biology. β’ Keywords: Extracellular matrix, Insulin resistance, Integrin lipid metabolism Liver metabolism
β’ O2k-Network Lab: US TN Nashville Wasserman DH
Labels: MiParea: Respiration, Exercise physiology;nutrition;life style
Pathology: Diabetes
Organism: Mouse Tissue;cell: Liver Preparation: Permeabilized tissue
Coupling state: LEAK, OXPHOS
Pathway: F, N
HRR: Oxygraph-2k