Antagonistic effects of bone morphogenetic protein-4 and -7 on renal mesangial cell proliferation induced by aldosterone through MAPK activation

• Published in: American journal of physiology. Renal physiology Vol. 292; no. 5; pp. F1513 - F1525
• Main Authors: Otani, Hiroyuki, Otsuka, Fumio, Inagaki, Kenichi, Takeda, Masaya, Miyoshi, Tomoko, Suzuki, Jiro, Mukai, Tomoyuki, Ogura, Toshio, Makino, Hirofumi
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.05.2007
• Subjects: Aldosterone - pharmacology; Animals; Biochemistry; Bone Morphogenetic Protein 4; Bone Morphogenetic Protein 7; Bone Morphogenetic Protein Receptors, Type I - metabolism; Bone Morphogenetic Proteins - antagonists & inhibitors; Bone Morphogenetic Proteins - pharmacology; Bones; Cell growth; Cell Line; Cell Proliferation - drug effects; Enzyme Activation; Extracellular Signal-Regulated MAP Kinases - metabolism; Hormones; JNK Mitogen-Activated Protein Kinases - metabolism; Kidneys; Mesangial Cells - cytology; Mice; Mineralocorticoid Receptor Antagonists; Mitogen-Activated Protein Kinases - metabolism; Mitosis - drug effects; Peptides; Phosphorylation - drug effects; Proteins; Rodents; Signal Transduction - drug effects; Smad6 Protein - metabolism; Spironolactone - analogs & derivatives; Spironolactone - pharmacology; Transforming Growth Factor beta - antagonists & inhibitors; Transforming Growth Factor beta - pharmacology
• ISSN: 1931-857X; 1522-1466
• DOI: 10.1152/ajprenal.00402.2006

Aldosterone and angiotensin II (ANG II) contribute to the development and progression of renal damage. Here we investigated the effects of bone morphogenetic proteins (BMPs) on renal cell proliferation evoked by aldosterone and ANG II with mouse mesangial cells, which express mineralocorticoid receptors (MR), ANG II type 1 receptors, and BMP signaling molecules. Aldosterone and ANG II stimulated mesangial cell mitosis and activated ERK1/2 and SAPK/JNK signaling. These aldosterone effects were neutralized by the MR antagonist eplerenone and inhibition of transcription or translation, suggesting the involvement of genomic activation via MR. BMP-4 and BMP-7 stimulated Smad1, -5, -8 signaling more potently than BMP-2 and BMP-6, leading to suppression of mesangial cell mitosis and MR expression. MAPK inhibitors including U-0126 and SP-600125, but not SB-203580, suppressed aldosterone-induced cellular DNA synthesis, implying that ERK1/2 and SAPK/JNK pathways play crucial roles in mesangial cell proliferation. BMP-4 and BMP-7 inhibited phosphorylation of ERK1/2 and SAPK/JNK induced by aldosterone while activating p38 pathway, resulting in inhibition of aldosterone-induced cell mitosis. In contrast, aldosterone modulated the mesangial BMP system by decreasing expression of ALK-3, BMP-4, and BMP-7 while increasing inhibitory Smad6 expression. Thus novel functional cross talk between the mesangial BMP system and aldosterone signaling was uncovered, in which inhibition of MAPK signaling and MR expression by BMP-4 and BMP-7 may be involved in ameliorating renal damage due to mesangial proliferation caused by aldosterone.