Integrin-mediated preadipocyte adhesion and migration on laminin-1.

Cell adhesion and migration are key events in many biological processes and depend on extracellular matrix proteins. Understanding these cellular events in adipogenesis is paramount to elucidating the biological mechanisms underlying preadipocyte-specific aspects of obesity, diabetes, and adipose tissue development for the design of pharmaceutical screening and tissue engineering strategies. We quantitatively investigated preadipocyte adhesion and migration on laminin-1 surfaces and identified candidate cognate preadipocyte receptors for laminin-1. In adhesion studies, we found that preadipocytes readily adhered to laminin-1 as compared with other extracellular matrix proteins. In addition, immunocytochemical analysis demonstrated that an array of integrin molecules was present on the surface of preadipocytes. Preadipocyte adhesion on laminin-1 was quantitatively assessed using a sedimentation adhesion assay, and results suggested that preadipocyte adhesion to laminin-1 was mediated by the alpha1beta1 integrin. In addition, digital time-lapse microscopy and quantitative cell tracking revealed that inhibition of the alpha1beta1 integrin resulted in abrogation of preadipocyte migration on laminin-1 surfaces. These results strongly support the hypothesis that preadipocyte adhesion to and migration on laminin-1 substrata are regulated, in part, by integrins.