Differential expression of proteins in omental and subcutaneous adipose tissue
María Insenser1,2, Rafael Montes1,2, Rafael Simó1,3, Joan Vendrell1,4 & Héctor F Escobar-Morreale1,2
Background: Adipose tissue is considered a highly active metabolic and endocrine organ with important physiological functions. The evaluation of protein expression has the potential advantage of providing a global vision of the cellular pathways associated with adipose tissue dysfunction and obesity, permitting the identification of novel candidate molecules that would have not been considered of interest otherwise.
Objectives: To identify proteins differentially expressed in subcutaneous and in omental adipose tissue from obese and non-obese patients by applying two-dimensional differential in gel electrophoresis (2D-DIGE).
Methods: Subcutaneous and omental adipose tissue was obtained from 12 patients (six male and six female), including six morbidly obese patients (age 36.6±16.3 years; BMI 51.85±8.4 kg/m2) and six non-obese patients (age 44±21.3 years; BMI 24.4±2.2 kg/m2).
Proteins from adipose tissue were extracted by using a homogenizer. 2D clean up kit was used to remove interfering components. The protein extracts (n=24) were analyzed 2D-DIGE. Protein spots showing significant differences between patients and controls were identified, excised, trypsin-digested and analyzed by matrix-assisted laser-desorption ionization time-of-flight time-of-flight (MALDI-TOF-TOF).
Results: This technology allowed the analysis of ~1700 protein spots in the comparative study of proteins. We considered changes within 95% confidence interval (P<0.05) and standardized average spots volume ratio exceeding 1.4 in at least 9 of the 12 gels analyzed. A total of 48 spots showing statistically significant differential expression between both tissues were identified. The validation of these spots by western blot and gene expression with real time PCR is ongoing at present.
Conclusions: There are differences in the proteomic profiles of subcutaneous and omental adipose tissue that are also modulated by the presence or absence of obesity. The precise identification of these proteins will provide some insight into the molecular events in visceral and omental adipose tissue associated with obesity.
Grants: FIS PI 080944, CIBERDEM CB07/08/.