Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 649-677-Adipocyte Biology
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-650
Wieland Kiess*1, Franziska Kässner2, Gordian Schmid2, Kathrin Landgraf2, Astrid Tannert3, Franziska Katharina Wilhelm4, Antje Andrea Garten4 and Antje Körner1
1University of Leipzig, Dept. of Women´s & Child Health, Leipzig, Germany, 2Childrens Hospital/University of Leipzig, Leipzig, Germany, 3Rudolf-Boehm-Institute for Pharmacology and Toxicology, 4Childrens Hospital/University of Leipzig
Aims: Human cell models are an important tool for the investigation of molecular mechanisms underlying adiposity. Till now only few in vitro human preadipocyte models are known. We aimed to compare a new human preadipocyte model termed LipPD1 derived from a resected lipoma carrying a deletion in the PTEN (phosphatase and tensin homolog) gene with the established SGBS (Simpson-Golabi-Behmel Syndrome) preadipocyte strain (1) concerning functional and signaling analysis.

Methods: Adipose differentiation was determined by Nile Red lipid staining and cell counting. To determine gene expression quantitative PCR was used. Lipolysis rates were measured by glycerol release after stimulation with isoproterenol. Insulin stimulated glucose uptake was quantified by measuring 14C-labelled 2-deoxyglucose uptake. PI3K (Phosphoinositide-3-kinase) activity was determined by applying FRAP (fluorescence redistribution after photobleaching)/TIRF (total internal reflection fluorescence) analysis.

Results: LipPD1 cells preserved a capacity for adipocyte differentiation of 55.1±4.2% for 29 population doublings. The expression of the adipocyte markers PPARy, FASN, adiponectin and AP2 (FABP4) during differentiation tended to be increased in LipPD1 compared to SGBS. Functional analysis revealed no significant differences between LipPD1 and SGBS in 2-deoxyglucose uptake after insulin stimulation. Lipolysis was activated by isoproterenol and not significantly different in LipPD1 compared to SGBS adipocytes. A fluorescent biomarker, reflecting PI3K activity by redistribution to the plasma membrane, was found membrane-associated to a significantly higher amount in LipPD1 (33.4±2.7%) compared to SGBS adipocytes (20.9±2.3%). A constitutive activation of the kinase AKT was verified by detecting significantly increased Ser473 and Thr308 phosphorylation in LipPD1 cells compared to SGBS. AKT phosphorylation was further enhanced after stimulation with IGF-I.

Conclusion: LipPD1 cells have increased PI3K/AKT activity compared to SGBS. In regard of their adipocyte functions LipPD1 behave like SGBS adipocytes and are a suitable model to investigate molecular mechanisms of adiposity.

(1) Wabitsch M et al, Int J Obes Relat Metab Disord. 2001;25:8.

Nothing to Disclose: WK, FK, GS, KL, AT, FKW, AAG, AK

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: Federal Ministry of Education and Research (BMBF), Germany, FKZ: 01EO1001; German Research Council (DFG, KFO152);  “Leipziger Forschungszentrum für Zivilisationserkrankungen” (LIFE Function);German Diabetes Society (DDG); Integrated Research and Treatment Center AdiposityDiseases (IFB) Leipzig, Germany