The influence of extracellular matrix substrata on preadipocyte development in serum-free cultures of stromal-vascular cells.

The influence of the extracellular matrix (ECM) and ECM components on preadipocyte development was examined in primary cultures of adipose tissue stromal-vascular (S-V) cells. Extracellular matrix derived from Engelbreth-Holm-Swarm (EHS) cells or tumors enhanced several aspects of adipogenesis in vitro. In comparison to uncoated and fibronectin substrata, EHS-ECM substratum markedly increased attachment, spreading, and hypertrophy of preadipocytes while antagonizing spreading of non-preadipocytes. In addition, adipocyte number increased (P < .05) on these substrata despite no increase in total cell number: this resulted in a greater (P < .05) proportion of preadipocytes. These effects of EHS-ECM were also observed with laminin substrata per se, whereas types I and IV collagen and fibronectin had no influence. In contrast to all other substrata, adipocyte number decreased and total cell number increased 2.5-fold on ECM derived from corneal endothelial cells; this resulted in the lowest proportion of preadipocytes. Challenging cultures with adipogenic media (+serum) did not counter the inhibitory influence of corneal endothelial ECM, whereas dexamethasone partially neutralized the inhibitory influence of this ECM. These studies clearly show that source or type of the ECM dictated the influence of ECM substrata on preadipocyte development in primary S-V cultures. However, these studies indicated that the ECM and in particular laminin may play a critical role in morphological aspects of preadipocyte development.