Profiling of the secreted proteins during 3T3-L1 adipocyte differentiation leads to the identification of novel adipokines

Profiling of the secreted proteins during 3T3-L1 adipocyte differentiation leads to the identification of novel adipokines.Wang P, Mariman E, Keijer J, Bouwman F, Noben JP, Robben J, Renes J.Maastricht Proteomics Center, The Nutrition and Toxicology Research Institute Maastricht (NUTRIM), Department of Human Biology, Maastricht University, 6200 MD Maastricht, The Netherlands.Adipose tissue is an endocrine organ capable of secreting a number of adipokines with a role in the regulation of adipose tissue and whole-body metabolism. We used two-dimensional gel electrophoresis combined with mass spectrometry to profile the secreted proteins from (pre)adipocytes. The culture medium of 3T3-L1 cells during adipocyte differentiation was screened, and 41 proteins that responded to blocking of secretion by 20 degrees C treatment and/or brefeldin A treatment were identified. Prohibitin, stress-70 protein, and adhesion-regulating molecule 1 are reported for the first time as secreted proteins. In addition, procollagen C-proteinase enhancer protein, galectin-1, cyclophilin A and C, and SF20/IL-25 are newly identified as adipocyte secreted factors. Secretion profiles indicated a dynamic environment including an actively remodeling extracellular matrix and several factors involved in growth regulation.