Identification of Novel Human Adipocyte Secreted Proteins by Using SGBS Cells

Adipose tissue is an endocrine organ secreting different types of proteins, known as adipokines. These adipokines play important roles in homeostasis and metabolism. Adipocyte differentiation leads to a change in adipokine secretion profile which is probably involved in disruption of homeostasis. Many adipokines have been identified but species differences and limitations of human adipose tissue material urged the need for better model systems. Here we used a human cell strain derived from a Simpson Golabi Behmel syndrome (SGBS) patient. SGBS cells have already been used in functional studies on adipocytes but not in a proteomic search for adipokines. In this study, 2D-MS/MS and nLC-MALDI-MS/MS were applied to investigate secretion profiles of SGBS adipokines. A total of 80 secreted proteins were identified; 6 proteins are novel adipocyte secreted proteins, 20 proteins have not been detected before in human adipose material and 23 additional proteins previously detected in visceral adipose tissue have been found here secreted by SGBS-cells of subcutaneous origin. It can be concluded that SGBS cells are both a valid human cell model for adipocyte secretion profiling and for searching for novel human (pre)adipocytes secreted proteins.