Effect of molecular weight of tyramine-modified hyaluronan on polarization state of THP-1 and peripheral blood mononuclear cells-derived macrophages

The immunomodulatory properties of hyaluronan and its derivatives are key to their use in medicine and tissue engineering. In this work we evaluated the capability of soluble tyramine-modified hyaluronan (THA) of two molecular weights (low Mw=280 kDa and high Mw=1640 kDa) for polarization of THP-1 and peripheral blood mononuclear cells (PBMCs)-derived macrophages (M{Phi}s). We demonstrate the polarization effects of the supplemented THA by flow cytometry and multiplex ELISA for the THP-1 derived M{Phi}s and by semi-automated image analysis from confocal microscopy, immunofluorescent staining utilising CD68 and CD206 surface markers, RT-qPCR gene expression analysis, as well as using the enzyme-linked immunosorbent assay (ELISA) for PBMCs-derived M{Phi}s. Our data indicate that supplementation with LMW THA drives changes in THP-1 derived M{Phi}s towards a pro-inflammatory M1-like phenotype, whereas supplementation with the HMW THA leads to a more mixed profile with some features of both M1 and M2 phenotypes, suggesting either a heterogeneous population or a transitional state. For cells directly sourced from human patients, PMBCs-derived M{Phi}s, results exhibit a higher degree of variability, pointing out a differential regulation of factors including IL-10 and CD206 between the two cell sources. While human primary cells add to the clinical relevance, donor diversity introduces wider variability in the dataset, preventing drawing strong conclusions. Nevertheless, the M{Phi}s profiles observed in THP-1 derived cells for treatments with LMW and HMW THA are generally consistent with what might be expected for the treatment with non-modified hyaluronans of respective molecular weights, confirming the known association holds true for the chemically tyramine-modified hyaluronan. We stipulate that these responses will provide basis for more accurate in vivo representation and translational immunomodulatory guidance for the use of THA-based biomaterials to a wider biomaterials and tissue engineering communities. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/575241v3_ufig1.gif" ALT="Figure 1"> View larger version (24K): org.highwire.dtl.DTLVardef@899d95org.highwire.dtl.DTLVardef@c8b80aorg.highwire.dtl.DTLVardef@1aad98dorg.highwire.dtl.DTLVardef@1b0ce60_HPS_FORMAT_FIGEXP M_FIG C_FIG