Monocytic U937 adhesion, tumor necrosis factor-alpha and interleukin-1 beta expression in response to gelatin-based networks grafted with arginine-glycine-aspartic acid and proline-histidine-serine-arginine-asparagine oligopeptides.

In this study we synthesized gelatin-based, tissue-engineering, interpenetrating network (IPN) scaffolds immobilized with fibronectin (FN)-derived peptides to assess monocyte-biomaterial interaction. Human promonocytic U937 cells were seeded onto peptide-grafted IPN or tissue-culture polystyrene plate (TCPS) pre-adsorbed with FN or FN-derived peptides. The presence of RGD influenced U937 density on IPN. Interleukin-1 beta (IL-1beta) messenger ribonucleic acid (mRNA) expression in adherent U937 on treated TCPS was slightly upregulated at 4 h. Tumor necrosis factor alpha (TNF-alpha) and IL-1beta mRNA expression in adherent U937 on all IPNs was generally downregulated at 4 h. This downregulation of IL-1beta mRNA apparently varied in IPNs grafted with different ligand and was still present at 24 h. TNF-alpha and IL-1beta proteins released from U937 on treated TCPS were comparable with the control at 24 h, but TNF-alpha and IL-1beta protein expression in U937 on IPNs was lower at 24 h than on the TCPS control. The results indicate that the tissue-engineering substrate and the bioactive peptides modulate the initial U937 adhesion and the subsequent inflammatory cytokine gene and protein expression.