Glomerular polyanion and control of cell function.

The glomerular polyanion comprises all anionic sites of glomerular cell surfaces, basement membranes and extracellular matrix. Charged structures may play a critical pathophysiologic role within the glomerular microcirculation, as loss of charges results in altered permselectivity of the filtration barrier and proteinuria. Neutralization of cell surface negative charges of cultured glomerular epithelial and mesangial cells by the polycation poly-L-lysine (PL) is accompanied by increased prostanoid synthesis. Recent studies have shown that PL enhances mesangial cell proliferation in culture. Conversely, the polyanion heparin prevents the effect of PL, and inhibits the growth-stimulatory effect of serum. Thus, our data suggest that the glomerular polyanion, in addition to maintaining the integrity of the filtration barrier, regulates key cell functions such as eicosanoid biosynthesis and proliferation.