Efficient material-induced activation of monocyte-derived dendritic cells releasing surface molecules, matrix metalloproteinases, and growth factors needed for regenerative tissue remodeling

Abstract

New experimental approaches for tissue repair have recently been proposed and include the application of natural or synthetic biomaterials and immune cells. Herein, fully synthetic poly(glycidyl ether) (PGE) copolymer coatings are evaluated as bioinstructive materials for the in vitro culture and intrinsic activation of human immune cells. Immature monocyte-derived dendritic cells (moDCs) are exposed to PGE brush and gel coatings of varying copolymer composition, wettability, and deformability immobilized on polystyrene culture dishes. Compared to moDCs cultured on standard tissue culture-treated polystyrene, activation marker levels on the cell surface are strongly enhanced on PGE substrates. Thereby, moDCs undergo a distinct morphological change and reach levels of activation comparable to those achieved by toll-like receptor (TLR) ligand liposaccharide (LPS), specifically for the expression of costimulatory molecules CD86 and CD40 as well as human leukocyte antigen (HLA)-DR. In addition, PGE coatings induce a significantly enhanced level of programmed cell death ligands 1 and 2 (PD-L1/-L2) on the moDC surface, two molecules crucially involved in maintaining immune tolerance. In addition, an increased release of matrix metalloproteinases MMP-1 and MMP-7, as well as transforming growth factor (TGF)-β1 and epidermal growth factor (EGF) was observed in moDCs cultured on PGE substrates. As fully synthetic biomaterials, PGE coatings demonstrate intrinsic functional competence in instructing immature human moDCs for phenotypic activation in vitro, accompanied by the secretion of bioactive molecules, which are known to be crucial for tissue regeneration. Hence, PGE coatings hold strong potential for immune-modulating implant coatings, while PGE-activated moDCs are promising candidates for future clinical cell-based immunoengineering therapies.