Either integrin subunit beta1 or beta3 is involved in mediating monocyte adhesion, IL-1beta protein and mRNA expression in response to surfaces functionalized with fibronectin-derived peptides.

We synthesized gelatin-based, interpenetrating network (IPN) scaffolds immobilized with fibronectin (FN)-derived peptides to assess monocyte-biomaterial interaction. Human primary monocytes were seeded onto peptide-grafted IPN or tissue-culture polystyrene (TCPS) pre-adsorbed with FN or FN-derived peptides. Monocyte cell density on both TCPS and IPN surfaces was higher in the presence of the arginine-glycine-aspartic acid (RGD) peptide. Pretreatment with anti-integrin beta1 or beta3 antibody decreased monocyte density on all ligand-modified TCPS and IPN. Interleukin-1 beta (IL-1beta) protein levels of cells on modified TCPS decreased over time. IL-1beta expression of monocytes in the presence of IPNs peaked at 24 h and then decreased through 168 h. Ligand identity did not affect IL-1beta expression in either TCPS or IPN samples. Pretreatment with anti-integrin beta1 or beta3 antibody reduced IL-1beta levels from both TCPS and IPN samples in a ligand-independent manner, particularly at 24 h. Monocytic IL-1beta mRNA expression in IPN samples without antibody pretreatment was highest at 2 h and decreased over time. IL-1beta mRNA expression in cells with anti-integrin beta1 or beta3 antibody pretreatment was similar to those without antibody pretreatment, except for methoxygrafted IPN samples. The change in IL-1beta mRNA expression did not correlate with changes in protein expression. The results indicate that monocyte adhesion was affected by the substrate and the RGD sequence and beta1 or beta3 containing integrin receptors. beta1- or beta3-containing integrin receptors were also involved in IL-1beta gene and protein expression in monocytes adhered to gelatin-based biomaterial surfaces.