Role of Receptor-Interacting Protein 140 in human fat cells

Abstract

BackgroundMice lacking Receptor-interacting protein 140 (RIP140) have reduced body fat which at least partly is mediated through increased lipid and glucose metabolism in adipose tissue. In humans, RIP140 is lower expressed in visceral white adipose tissue (WAT) of obese versus lean subjects. We investigated the role of RIP140 in human subcutaneous WAT, which is the major fat depot of the body.MethodsMessenger RNA levels of RIP140 were measured in samples of subcutaneous WAT from women with a wide variation in BMI and in different human WAT preparations. RIP140 mRNA was knocked down with siRNA in in vitro differentiated adipocytes and the impact on glucose transport and mRNA levels of target genes determined.ResultsRIP140 mRNA levels in subcutaneous WAT were decreased among obese compared to lean women and increased by weight-loss, but did not associate with mitochondrial DNA copy number. RIP140 expression increased during adipocyte differentiation in vitro and was higher in isolated adipocytes compared to corresponding pieces of WAT. Knock down of RIP140 increased basal glucose transport and mRNA levels of glucose transporter 4 and uncoupling protein-1.ConclusionsHuman RIP140 inhibits glucose uptake and the expression of genes promoting energy expenditure in the same fashion as the murine orthologue. Increased levels of human RIP140 in subcutaneous WAT of lean subjects may contribute to economize on energy stores. By contrast, the function and expression pattern does not support that RIP140 regulate human obesity.

Early B Cell Factor 1 Regulates Adipocyte Morphology and Lipolysis in White Adipose Tissue

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Twist1 in Human White Adipose Tissue and Obesity

“…Values are presented as range (mean Ϯ SD). Cohort 4, previously described (23), comprised 24 obese (23 women and one man, age 42 Ϯ 10 yr; BMI 44 Ϯ 4 kg/m 2 ) and 15 lean subjects (12 women and 2 men, age 41 Ϯ 13 yr; BMI 24 Ϯ 2 kg/m 2 ) from whom paired samples of sc and omental WAT were obtained during elective abdominal surgery for nonmalignant disorders. Subjects in cohorts 1, 2, and 3 were investigated after an overnight fast, and only saline was given as an iv infusion until adipose tissue was removed.…”

Liver X receptors and fat cell metabolism

“…8 In addition to genetic polymorphisms, expression of two LXR co-regulators (CIDEA and RIP-140) is downregulated in obese adipose tissue, which could result in altered LXR signaling. 106, 107 …”