TGF-β suppresses POEM expression through ERK1/2 and JNK in osteoblasts

POEM, also called nephronectin, is an extracellular matrix protein that is considered to play a critical role as an adhesion molecule in the development and functioning of various tissues, such as kidneys and bones. In the present study, we examined the molecular mechanism of POEM gene expression, and found that transforming growth factor-β (TGF-β) strongly inhibited POEM expression in the mouse osteoblastic cell line, MC3T3-E1. TGF-β-induced decrease of POEM expression occurred in both time- and dose-dependent manners through the activation of TGF-β receptor I and extracellular signal-regulated kinase/c-Jun N-terminal kinase pathways.