Identification of adipocyte genes regulated by caloric intake

• CONTEXT: Changes in energy intake have marked and rapid effects on metabolic functions and some of the effects may be due to changes in adipose tissue gene expression that precede alterations in body weight. OBJECTIVE: To identify genes in adipose tissue regulated by changes in caloric intake independent of changes in body weight. RESEARCH DESIGN AND METHODS: Obese subjects were given a very-low calorie diet (VLCD; 450 kcal/day) for 16 weeks. After the diet, ordinary food was gradually reintroduced during 2 weeks while there were minimal changes in body weight. Adipose tissue gene expression was measured by microarray analysis. First, genes regulated during caloric restriction and in the opposite direction during the weight stable re-feeding phase were identified. To verify opposite regulation to that observed during caloric restriction, identified genes were further analyzed using adipocyte expression profiles from healthy subjects before and after overfeeding. Results were confirmed using real time PCR or immunoassay. RESULTS: Using a significance level of p<0.05 for all comparisons, 52 genes were downregulated and 50 were up-regulated by caloric restriction and regulated in the opposite direction by re-feeding and overfeeding. Among these were genes that affect lipogenesis (ACLY, ACACA, FASN, SCD), protein synthesis (4EBP1, 4EBP2), beta-oxidation (CPT1B), liberation of fatty acids (CIDEA) and glyceroneogenesis (PCK2). Interestingly, several of these are under control of the master regulator mTOR. CONCLUSIONS: The observed transcriptional changes indicate that mTOR plays a central role in the control of diet-regulated adipocyte genes involved in lipogenesis and protein synthesis.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Endokrinologi och diabetes (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Endocrinology and Diabetes (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Dermatologi och venereologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Dermatology and Venereal Diseases (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Kardiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cardiac and Cardiovascular Systems (hsv//eng)

Nyckelord

Obesity

DNA microarray

caloric restriction

overfeeding

adipose tissue

MEDICINE

MEDICIN

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