Attachment, proliferation and adipogenic differentiation of adipo-stromal cells on self-assembled monolayers of different chemical compositions

The objective of this study is to investigate the spreading area, proliferation and adipogenic differentiation of adipo-stromal cells cultured on the surface of self-assembled monolayers (SAM) prepared by alkanethiols with hydroxyl (OH), methyl (CH(3)), amine (NH(2)) and carboxyl terminal groups (COOH) or the mixture at different ratios. A modified enzyme-linked immunosorbent assay (ELISA) examination revealed that a high adsorption of vitronectin and fibronectin was observed for the SAM of NH(2) or the mixed SAM of OH and NH(2) groups and the mixed SAM of OH and CH(3) or OH and COOH groups, respectively. The cell spreading area and the proliferation level were higher for the SAM of NH(2) or COOH or the mixed SAM of OH and NH(2) or OH and COOH groups than those of other substrates. When incubated in an adipogenic differentiation medium, the cells showed a high level of glycerol-3-phosphate dehydrogenase (GPDH) activity for the SAM of CH(3) or the mixed SAM of OH and COOH groups. In addition, a high mRNA expression of peroxisome proliferator-activated receptor gamma2 (PPRAgamma2) and fatty acid binding protein 2 (aP2) was observed. For the SAM of NH(2) or COOH groups, the strong activation of extracellular signal-regulated kinase 1 and 2 (ERK1/2) was observed while the mRNA expression of connective tissue growth factor (CTGF) and cysteinrich 61 (CYR61) was enhanced. The proliferation of the cells was significantly suppressed by adding an inhibitor of ERK1/2. The mRNA expression of PPAR gamma2 was significantly induced by adding the inhibitor. It is concluded that the proliferation and adipogenic differentiation of adipo-stromal cells depended on the chemical composition of substrate surface, although the extent was influenced by that of ERK1/2 activation.