Abstract 17405: MicroRNA-205 Knockdown Induces Preadipocyte Cell Proliferation and Adipogenesis in Visceral Adipose of Obese Mice
Introduction: Central obesity involves deposition of fat around the trunk and in visceral adipose (VA) tissue. It is more common in men and carries a higher risk of CVD, dyslipidemia and T2D. In obese individuals, the increase in adiposity results from increases in the number and size of adipocytes, while the degree of hypertrophy relative to hyperplasia influences the level of body fat and the metabolic consequences of obesity.
Hypothesis: miR-205 expression is increased in differentiated adipocytes and its inhibition leads to visceral adiposity.
Methods: NONcNZO10 (NZ10) mice with polygenic susceptibility to T2D or SWR controls were fed Control (CD) or South Beach (SD; high protein/unsaturated fat) diets for 25 weeks. After 12 hr. fasting the mice were sacrificed and VA was collected. Total RNA was isolated and subjected to Sanger 14 multi-species miRNA microarray. Mouse 3T3-L1 preadipocytes were cultured in either preadipocyte maintenance medium or DM2 adipogenic differentiation medium. Preadipocytes were transfected with both pre and anti-miR-205 precursor and inhibitor molecules using OPTI-MEM and NeoFx transfection agent.
Results: Visceral adiposity was not induced in the control SWR fed either diet or NZ10 mice fed south beach diet as can be assessed by their body weights and percent fat levels (p<0.01). NZ10mice fed CD were hyperglycemic with impaired glucose tolerance test and hyperinsulinemic; gene expression analysis showed significant induction of key adipogenic genes; PPAR gamma and FABP4 in the VA of these mice. Microarray and real time PCR data revealed 10-fold down regulation of miR-205 in the VA of NZ10 mice fed CD vs SD or SWR mice fed either diet. miR-205 inhibition using anti-miR-205 inhibitor molecules in 3T3-L1 cells significantly increased cell proliferation as assessed by BrdU assay (p<0.001). Oil Red O staining of differentiating adipocytes with miR-205 knocked down showed increased staining for lipids (p<0.001). Also real time PCR analysis revealed increased mR-205 expression in differentiated adipocytes over preadipocytes (p<0.001).
Conclusions: miR 205 inhibition increases preadipocyte cell proliferation and adipogenesis in the visceral adipose of obese mice.
- © 2011 by American Heart Association, Inc.