The effects of hyaluronan oligosaccharides.

To investigate the effects of hyaluronan oligosaccharides(o-HA) on the proliferation and the migration of endothelial cells(EC),as well as the mechanisms of its involvement in angiogenesis，porcine vascular endothelial cells (PIECs) were treated with o-HA and the cell proliferation was determined by cell counting and flow cytometry. The cell viability and motility were assessed by MTT and wound recovery assays, respectively. The results indicated that o-HA caused a significant increase of PIEC proliferation and migration after o-HA treatments. An increased expression of CD44 Antibody c-Myc and cyclin D1 induced by o-HA was observed by Western blotting. The levels of phosphorylated Src kinase and ERK-1/2 were also upregulated after o-HA treatments. To further distinguish which of the two known HA receptors, namely CD44 and RHAMM, is responsible for the downstream tyrosine phosphorylation, o-HA treated PIECs were pre-blocked with the anti-RHAMM antibody or the anti-CD44 antibody, then assayed for ERK-1/2 phosphorylation by immunoblotting with an anti-phospho-ERK-1/2 antibody. We found that only the anti-RHAMM antibody slightly inhibited o-HA-induced tyrosine phosphorylation of ERK-1/2 . The results suggested that in vitro pro-proliferation effect of o-HA in ECs,. Anti-CD44 was mediated by RHAMM receptors, resulted in the activation of the Src kinase and MAPK(ERK-1/2) signal pathway and thus promoted the cell proliferation with the involvement of cyclin D1 expression.