TGFbeta1 is involved in high glucose-induced accumulation of pericellular chondroitin sulphate in human endothelial cells

Abstract

High glucose-induced endothelial cell dysfunction is considered to be the main cause of the development of vascular diabetes complications. Cultured endothelial cells exposed to high glucose in vitro demonstrate a variety of alterations, including extracellular matrix (ECM) deposition, growth inhibition, and changes in cell motility. Some of these effects were shown to be mediated by the up-regulation of endothelial transforming growth factor-beta1 (TGFbeta1) secretion and activation. We investigated the influence of high glucose on human immortalized endothelial cell line ECV304. According to our data, confluent cells exposed to 30 mM glucose for 48h secrete the increased amount of total and active TGFbeta1 (∼1.4-fold), and accumulate more chondroitin sulphate (CS) in their conditioned medium, pericellular matrix, and cell layer (∼1.6- to 2.0-fold). By blocking the coupling of CS chains to the core protein with p-nitrophenyl-β- d-xyloside and by chondroitinase ABC treatment, we demonstrated that the increased accumulation of pericellular CS is accompanied by increased cell attachment to immobilized hyaluronic acid (HA), while the expression of cell surface CD44 remains unaltered. Since the exogenous TGFbeta1 affects ECV304 cells in a similar manner, and anti-TGFbeta1-neutralizing antibody cancels the effect of high glucose, we suggest the involvement of TGFbeta1 in the development of endothelial cell response to high glucose in terms of CS accumulation and cell binding to HA.