Specific tissue distribution of megsin, a novel serpin, in the glomerulus and its up-regulation in IgA nephropathy

Mesangial cells play critical roles in maintaining a structure and function of the glomerulus. We previously cloned a novel mesangium-predominant gene , megsin, a new serine protease inhibitor. To clarify localization and role s of megsin protein, we raised polyclonal antibodies to megsin. By immunohi stochemistry, megsin protein was specifically identified in the mesangial a rea. The amount of megsin protein was increased in glomeruli of patients wi th IgA nephropathy than in those of normal individuals and of patients with minimal change nephrotic syndrome or membranous nephropathy, suggesting a pathophysiological role of megsin as a functional modulator of mesangial fu nctions in situ. (C) 2001 Academic Press.