Untersuchung zur Rolle von HMGA2 im Fettgewebe: Mechanismen des Turnovers und der Hyperplasie

Adipose tissue expansion, which leads to overweight and obesity, is based on an increase in the number (hyperplasia) and volume (hypertrophy) of adipocytes. A cascade of transcription factors regulates the highly dynamic differentiation process during adipogenesis. This thesis analyzed the molecular mechanisms of adipocyte hyperplasia and turnover in adipose tissue, lipomas and ADSCs, focussing on HMGA2 participation. HMGA2 is considered to be a protein that is apparently linked to the process of proliferation and differentiation of cells. Investigation of human and canine abdominal subcutaneous white adipose tissue revealed a significantly higher expression of HMGA2 in overweight individuals compared to those of normal weight. The results indicate that the gain of body weight is due to hyperplasia of preadipocytes which are not or hardly able to differentiate to mature insulin-sensitive adipocytes. Furthermore, a significant increase of HMGA2 expression in patients with type II diabetes could be detected. In summary, this thesis highlight the important role of HMGA2 during adipogenesis, the cellular composition of adipose tissue and its possible influence on type II diabetes.