Article

Diabetologia

, Volume 51, Issue 1, pp 155-164

Fat depot-related differences in gene expression, adiponectin secretion, and insulin action and signalling in human adipocytes differentiated in vitro from precursor stromal cells

  • S. PerriniAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , L. LaviolaAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , A. CignarelliAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , M. MelchiorreAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , F. De StefanoAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , C. CaccioppoliAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , A. NatalicchioAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , M. R. OrlandoAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
  • , G. GarrutiAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
    • , M. De FazioAffiliated withDepartment of Emergency and Organ Transplantation, Section of General Surgery, University of Bari School of Medicine
    • , G. CatalanoAffiliated withDepartment of Emergency and Organ Transplantation, Section of General Surgery, University of Bari School of Medicine
    • , V. MemeoAffiliated withDepartment of Emergency and Organ Transplantation, Section of General Surgery, University of Bari School of Medicine
    • , R. GiorginoAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of Medicine
    • , F. GiorginoAffiliated withDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari School of MedicineDepartment of Emergency and Organ Transplantation, Section of Internal Medicine, Endocrinology and Metabolic Diseases, University of Bari Email author 

Abstract

Aim/hypothesis

The distinct metabolic properties of visceral and subcutaneous adipocytes may be due to inherent characteristics of the cells that are resident in each fat depot. To test this hypothesis, human adipocytes were differentiated in vitro from precursor stromal cells obtained from visceral and subcutaneous fat depots and analysed for genetic, biochemical and metabolic endpoints.

Methods

Stromal cells were isolated from adipose tissue depots of nondiabetic individuals. mRNA levels of adipocyte-specific proteins were determined by real-time RT-PCR. Insulin signalling was evaluated by immunoblotting with specific antibodies. Glucose transport was measured by a 2-deoxy-glucose uptake assay. Adiponectin secretion in the adipocyte-conditioned medium was determined by a specific RIA.

Results

With cell differentiation, mRNA levels of PPARG, C/EBPα (also known as CEBPA), AP2 (also known as GTF3A), GLUT4 (also known as SLC2A4) were markedly upregulated, whereas GLUT1 (also known as SLC2A1) mRNA did not change. However, expression of C/EBPα, AP2 and adiponectin was higher in subcutaneous than in visceral adipocytes. By contrast, adiponectin was secreted at threefold higher rates by visceral than by subcutaneous adipocytes while visceral adipocytes also showed two- to threefold higher insulin-stimulated glucose uptake. Insulin-induced phosphorylation of the insulin receptor, IRS proteins, Akt and extracellular signal-regulated kinase-1/2 was more rapid and tended to decrease at earlier time-points in visceral than in subcutaneous adipocytes.

Conclusions/interpretation

Subcutaneous and visceral adipocytes, also when differentiated in vitro from precursor stromal cells, retain differences in gene expression, adiponectin secretion, and insulin action and signalling. Thus, the precursor cells that reside in the visceral and subcutaneous fat depots may already possess inherent and specific metabolic characteristics that will be expressed upon completion of the differentiation programme.

Keywords

Adiponectin Akt Erk Extracellular signal-regulated kinase Glucose uptake Insulin signalling Subcutaneous fat Visceral fat