Inhibition of adenosine monophosphate-activated protein kinase suppresses bone morphogenetic protein-2-induced mineralization of osteoblasts via Smad-independent mechanisms.

Inhibition of adenosine monophosphate-activated protein kinase suppresses bone morphogenetic protein-2-induced mineralization of osteoblasts via Smad-independent mechanisms.
Endocr J. 2017 Dec 16;:
Authors: Takeno A, Kanazawa I, Notsu M, Tanaka KI, Sugimoto T
Abstract
Previous studies showed that adenosine monophosphate-activated protein kinase (AMPK), which plays as an intracellular energy sensor, promotes the differentiation and mineralization of osteoblasts via enhancing expression of bone morphogenetic protein (BMP)-2, which is a potent inducer of osteoblastogenesis. Thus, the aim of this study was to examine the roles of AMPK in BMP-2-induced osteoblastogenesis. We used a murine osteoblastic cell line MC3T3-E1 and a murine marrow stromal cell line ST2. BMP-2 (50 and 100 ng/mL) stimulated alkaline phosphatase (ALP) activity and enhanced mineralization of MC3T3-E1 cells, while the effects of BMP-2 were partly abolished by an inhibitor of AMPK, ara-A (0.1 mM). Real-time PCR showed that BMP-2 significantly increased the mRNA expressions of Alp, osteocalcin (Ocn), Runx2, Osterix and Dlx-5 in MC3T3-E1 cells, while co-incubation of ara-A significantly decreased the BMP-2-stimulated expression of Alp, Ocn, and Runx2. Moreover, co-incubation of ara-A suppressed the BMP-2-induced upregulation of Alp and Ocn in ST2 cells. Western blot analysis showed that BMP-2 phosphorylated Smad1/5 although it did not affect AMPK phosphorylation in MC3T3...

Source: Endocrine Journal - December 19, 2017 Category: Endocrinology Tags: Endocr J Source Type: research