Oh YS, Khil LY, Cho KA, Ryu SJ, Ha MK, Cheon GJ, Lee TS, Yoon JW, Jun HS, Park SC. A potential role for skeletal muscle caveolin-1 as an insulin sensitivity modulator in ageing-dependent non-obese type 2 diabetes: studies in a new mouse model.
Diabetologia 2008;
51:1025-34. [PMID:
18408913 DOI:
10.1007/s00125-008-0993-0]
[Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Accepted: 02/21/2008] [Indexed: 10/22/2022]
Abstract
AIMS/HYPOTHESIS
Type 2 diabetes mellitus is a common age-dependent disease. We discovered that male offspring of non-diabetic C57BL/6 and DBA/2 mice, called JYD mice, develop type 2 diabetes when they grow old. JYD mice show characteristics of insulin resistance, hyperglycaemia and hyperinsulinaemia in old age without obesity. We postulated that the mechanism of age-dependent type 2 diabetes in this model relates to caveolin-1 status in skeletal muscle, which appears to regulate insulin sensitivity in the mice.
METHODS
We compared insulin sensitivity in aged C57BL/6 and JYD mice using glucose and insulin tolerance tests and (18)F-fluorodeoxyglucose positron emission tomography. We also determined insulin signalling molecules and caveolin proteins using western blotting, and altered caveolin-1 levels in skeletal muscle of C57BL/6 and JYD mice using viral vector systems, to examine the effect of this on insulin sensitivity.
RESULTS
In 30-week-old C57BL/6 and JYD mice, the basal levels of IRS-1, Akt and peroxisome proliferator-activated receptor-gamma decreased, as did insulin-stimulated phosphorylation of Akt and insulin receptor beta. However, caveolin-1 was only increased about twofold in 30-week-old JYD mice as compared with 3-week-old mice, whereas an eightfold increase was seen in C57BL/6 mice. Downregulation of caveolin-1 production in C57BL/6 mice caused severe impairment of glucose and insulin tolerance. Upregulation of caveolin-1 in aged diabetic JYD mice significantly improved insulin sensitivity with a concomitant increase of glucose uptake in the skeletal muscle.
CONCLUSIONS/INTERPRETATION
The level of skeletal muscle caveolin-1 is correlated with the progression of age-dependent type 2 diabetes in JYD mice.
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