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Adipophilin protein expression in muscle – a possible protective role against insulin resistance
Author(s) -
de Wilde Janneke,
Smit Egbert,
Snepvangers Frank J. M.,
de Wit Nicole W. J.,
Mohren Ronny,
Hulshof Martijn F. M.,
Mariman Edwin C. M.
Publication year - 2010
Publication title -
the febs journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.981
H-Index - 204
eISSN - 1742-4658
pISSN - 1742-464X
DOI - 10.1111/j.1742-4658.2009.07525.x
Subject(s) - perilipin , endocrinology , medicine , insulin resistance , palmitic acid , peroxisome proliferator activated receptor , lipid droplet , oleic acid , triglyceride , chemistry , peroxisome , fatty acid binding protein , biology , adipose tissue , fatty acid , receptor , insulin , biochemistry , adipocyte , cholesterol , gene
Adipophilin is a 50 kDa protein that belongs to the PAT family (perilipin, adipophilin, TIP47, S3‐12 and OXPAT), which comprises proteins involved in the coating of lipid droplets. Little is known about the functional role of adipophilin in muscle. Using the C2C12 cell line as a model, we demonstrate that palmitic acid‐treated cells highly express the adipophilin protein in a dose‐dependent way. Next, we show that oleic acid is a more potent inducer of adipophilin protein levels than palmitic acid. Cells treated with oleic acid have a higher adipophilin protein expression and higher triglyceride levels but less impairment of insulin signaling than cells treated with palmitic acid. Additionally, we show that peroxisome proliferator‐activated receptor (PPAR)α, PPARβ/δ and PPARγ agonists all increase the expression of the adipophilin protein in C2C12 cells. This effect was most pronounced for the PPARα agonist GW7647. Furthermore, the expression of adipophilin as a 37 kDa N‐terminally truncated protein is higher in the gastrocnemius than in the quadriceps of C57BL/6J mice, especially after an 8‐week high‐fat diet. The expression of adipophilin was higher in the muscle of mice fed a 4‐week high‐fat diet based on olive oil or safflower oil than in mice fed a 4‐week high‐fat diet based on palm oil. After 2 weeks of intervention, plasma glucose, plasma insulin and the homeostasis model assessment of insulin resistance index were lower in mice fed a 4‐week high‐fat diet based on olive oil or safflower oil than in mice fed a 4‐week high‐fat diet based on palm oil. Taken together, the results obtained in the present study indicate that adipophilin protein expression in muscle is involved in maintaining insulin sensitivity.