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Updated: May 20, 2026

Isolation and Culture of Cells from the Nephrogenic Zone of the Embryonic Mouse Kidney
Published on: April 22, 2011
Nephronectin expression is regulated by SMAD signaling in osteoblast-like MC3T3-E1 cells
Masayuki Tsukasaki1, Atsushi Yamada, Kentaro Yoshimura
1Department of Biochemistry, School of Dentistry, Showa University, Tokyo, Japan.
Abstract:
Nephronectin (Npnt) is an extracellular matrix protein known to be a ligand for the integrin α8β1. We previously demonstrated that Npnt expression was suppressed by TGF-β through ERK1/2 and JNK in osteoblasts. In this study, we found that inhibition of a TGF-β type I receptor (TGF-β R1, Alk5) by a specific inhibitor {2-[3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl]-1,5-naphthyridine} strongly induced Npnt expression in osteoblast-like MC3T3-E1 cells. The Alk5 inhibitor-induced increase of Npnt expression occurred in both time- and dose-dependent manners, while that expression was also induced by introduction of an siRNA for Smad2, a central intracellular mediator of TGF-β signaling. These results suggest that the expression of Npnt is regulated by the Alk5-SMAD signaling pathway in osteoblasts.
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