C-Type Natriuretic Peptide Inhibits Proliferation and Monocyte Chemoattractant Protein-1 Secretion in Cultured Human Mesangial Cells

Abstract

Background: Mesangial cell proliferation and matrix accumulation are hallmarks of various progressive glomerular diseases. We examined whether C-type natriuretic peptide (CNP) that is known to regulate the proliferation of vascular smooth muscle cells could modulate these pathological processes using human glomerular mesangial cells (GMCs) in culture. Methods: Proliferation of GMCs cultured with different concentrations of CNP-22 for 48 h was determined by a colorimetric assay using a tetrazorium salt. Monocyte chemoattractant protein-1 (MCP-1) and type IV collagen secretion into the culture media by GMCs in the presence or absence of CNP-22 were evaluated by ELISA. Expression of mRNA for natriuretic peptide receptor B (NPR-B), a specific receptor for CNP, was examined by reverse transcription polymerase chain reaction (RT-PCR). Results: CNP-22 (1–10 µM) inhibited serum-induced GMC growth in a dose-dependent manner. The amount of MCP-1 in the culture supernatant was increased approximately 2.4-fold by 5 µg/ml of lipopolysaccharide. This increase was inhibited by CNP-22 at 0.1–1 µM in a dose-dependent fashion. CNP-22 (10 µM) inhibited GMC type IV collagen secretion stimulated by 20 ng/ml of platelet-derived growth factor. Expression of NPR-B mRNA was confirmed in GMCs by RT-PCR. Conclusions: CNP suppresses GMC proliferation and MCP-1 and type IV collagen secretion by GMCs. It may have a therapeutic potential against human proliferative glomerular diseases, especially those with the involvement of monocytes.