Oxidation of mesangial matrix using a mixed function oxidase system augments adhesion of macrophages: possible role of macrophage scavenger receptors.

Oxygen radicals are believed to play a role in the pathogenesis of aging and glomerular injury. Changes in cellular function may result from modification of the extracellular matrix with which they interact. We produced oxidized mesangial matrix protein using a mixed function oxidase system. Carbonyl content of the oxidized matrix was significantly increased. Adhesion of macrophages to the oxidized mesangial matrix was significantly enhanced, an effect which was significantly abrogated by scavenger receptor blockade with polyinosinic acid or dextran sulfate. Neither polyinosinic acid nor dextran sulfate diminished macrophage adhesion to unmodified matrix. These data demonstrate for the first time that mesangial matrix can undergo oxidation and that such oxidation may promote accumulation of macrophages in the mesangium via interaction of macrophage scavenger receptors with oxidized matrix proteins.