A new model of primary human adipocytes reveals reduced early insulin signalling in type 2 diabetes

TY - JOUR

T1 - A new model of primary human adipocytes reveals reduced early insulin signalling in type 2 diabetes

AU - Algenstaedt, P

AU - Rosenblatt, N

AU - Kolb, I

AU - Krützelmann, A

AU - Schwarzloh, B

AU - Böttcher, A

AU - Wiesner, L

AU - Greten, H

AU - Hansen-Algenstaedt, N

PY - 2004/8/1

Y1 - 2004/8/1

N2 - The aim of this study was to establish a diabetic model of primary human adipocytes for investigating potential defects in early insulin signalling. Specimens of human subcutaneous adipose tissue were obtained during orthopaedic surgical procedures. Preadipocytes were isolated and differentiated to adipocytes. Western blot analysis and immunoprecipitation were performed to determine protein content of IRS-1, IRS-2, p85, phosphorylation of IRS-1, IRS-2, Akt and MAPK as well as association between p85 and IRS-1/IRS-2. In addition to short-term insulin stimulation, the effect of hyperinsulinaemia was investigated by treating cells with insulin over a period of 36 hours. We found a significantly reduced basal expression of IRS-1 (54 +/- 15%) in adipocytes from type 2 diabetic subjects compared to controls with a further significant reduction in expression after long-term treatment (30 +/- 12%) compared to short-term treatment. IRS-2 expression also showed a significant reduction under hyperinsulinaemic conditions (20 +/- 2%) in diabetics vs. controls. Furthermore, long-term treatment with insulin in diabetic adipocytes led to a significant reduction in the phosphorylation of IRS-1(68 +/- 11%), IRS-2 (82 +/- 11%), Akt (42 +/- 2%), and MAPK (92 +/- 12%) and in the subsequent association between p85 to IRS-1 and IRS-2 (100 +/- 16% and 96 +/- 12%) in comparison to controls. Investigating glucose uptake diabetic adipocytes revealed a significant reduction of 90 +/- 2%. In this study, we were able to establish a new diabetic model of primary human adipocytes. A defect in early insulin signalling in type 2 diabetic patients under hyperinsulinaemic conditions was determined. These results might help to give further insights in early insulin action; additionally, this human model represents a useful target for the study of new therapeutic approaches.

AB - The aim of this study was to establish a diabetic model of primary human adipocytes for investigating potential defects in early insulin signalling. Specimens of human subcutaneous adipose tissue were obtained during orthopaedic surgical procedures. Preadipocytes were isolated and differentiated to adipocytes. Western blot analysis and immunoprecipitation were performed to determine protein content of IRS-1, IRS-2, p85, phosphorylation of IRS-1, IRS-2, Akt and MAPK as well as association between p85 and IRS-1/IRS-2. In addition to short-term insulin stimulation, the effect of hyperinsulinaemia was investigated by treating cells with insulin over a period of 36 hours. We found a significantly reduced basal expression of IRS-1 (54 +/- 15%) in adipocytes from type 2 diabetic subjects compared to controls with a further significant reduction in expression after long-term treatment (30 +/- 12%) compared to short-term treatment. IRS-2 expression also showed a significant reduction under hyperinsulinaemic conditions (20 +/- 2%) in diabetics vs. controls. Furthermore, long-term treatment with insulin in diabetic adipocytes led to a significant reduction in the phosphorylation of IRS-1(68 +/- 11%), IRS-2 (82 +/- 11%), Akt (42 +/- 2%), and MAPK (92 +/- 12%) and in the subsequent association between p85 to IRS-1 and IRS-2 (100 +/- 16% and 96 +/- 12%) in comparison to controls. Investigating glucose uptake diabetic adipocytes revealed a significant reduction of 90 +/- 2%. In this study, we were able to establish a new diabetic model of primary human adipocytes. A defect in early insulin signalling in type 2 diabetic patients under hyperinsulinaemic conditions was determined. These results might help to give further insights in early insulin action; additionally, this human model represents a useful target for the study of new therapeutic approaches.

KW - Adipocytes

KW - Aged

KW - Case-Control Studies

KW - Cell Differentiation

KW - Cells, Cultured

KW - Deoxyglucose

KW - Diabetes Mellitus, Type 2

KW - Female

KW - Humans

KW - Hyperinsulinism

KW - Insulin

KW - Insulin Receptor Substrate Proteins

KW - Intracellular Signaling Peptides and Proteins

KW - Male

KW - Middle Aged

KW - Mitogen-Activated Protein Kinases

KW - Phosphatidylinositol 3-Kinases

KW - Phosphoproteins

KW - Phosphorylation

KW - Protein-Serine-Threonine Kinases

KW - Proto-Oncogene Proteins

KW - Proto-Oncogene Proteins c-akt

KW - Signal Transduction

KW - Time Factors

U2 - 10.1055/s-2004-825798

DO - 10.1055/s-2004-825798

M3 - SCORING: Journal article

C2 - 15326562

VL - 36

SP - 531

EP - 537

JO - HORM METAB RES

JF - HORM METAB RES

SN - 0018-5043

IS - 8

ER -