Regulation of cultured human mesangial cell growth by ionized macromolecules.

We evaluated the importance of the net charge of polyionic macromolecules in the regulation of cultured human mesangial cell growth. Structurally unrelated polyanionic compounds, i.e., heparin, suramin, poly-L-aspartic acid, and poly-L-glutamic acid, strongly inhibited 10% fetal bovine serum-stimulated cell proliferation. On the other hand, two polycations, protamin sulfate and poly-L-lysine, were equally effective in inhibiting cell growth. The antiproliferative activity of each compound was neutralized by molecules with opposite net charge. These data indicate that both anionic and cationic macromolecules exert an antimitogenic effect on cultured human mesangial cells. This inhibitory effect is dependent upon charge density rather than on the net electric charge of each compound.