Sphingosine-1-phosphate/S1PR2-mediated signaling triggers Smad1/5/8 phosphorylation and thereby induces Runx2 expression in osteoblasts

Katsumasa Higashi, Etsuko Matsuzaki, Yoko Hashimoto, Fumi Takahashi-Yanaga, Aiko Takano, Hisashi Anan, Masato Hirata, Fusanori Nishimura

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Sphingosine-1-phosphate (S1P) is a signaling sphingolipid that also plays crucial roles in bone regeneration. Recently, we reported that the S1P receptors S1PR1 and S1PR2 were mainly expressed in osteoblast-like cells, and that the S1P/S1PR1 signaling pathway up-regulated osteoprotegerin and osteoblast differentiation. However, the involvement of S1P/S1PR2 signaling in osteoblast differentiation is not well understood. Here we investigate the role of S1P/S1PR2-mediated signaling in osteoblast differentiation and clarify the underlying signaling mechanisms. We found that an S1P/S1PR2/Gi-independent signaling pathway activated RhoA activity, leading to phosphorylation of Smad1/5/8 in mouse osteoblast-like MC3T3-E1 cells and primary osteoblasts. Furthermore, this signaling pathway promoted nuclear translocation of Smad4, and increased the amount of Smad6/7 protein in the nucleus. S1P also up-regulated runt-related transcription factor 2 (Runx2) expression through S1PR2/RhoA/ROCK/Smad1/5/8 signaling. Moreover, we found that S1P partially triggered S1PR2/RhoA/ROCK pathway leading to bone formation in vivo. These findings suggest that S1P induces RhoA activity, leading to the phosphorylation of Smad1/5/8, thereby promoting Runx2 expression and differentiation in osteoblasts. Our findings describe novel molecular mechanisms in S1P/S1PR2-mediated osteoblast differentiation that could aid future studies of bone regeneration.

Original languageEnglish
Pages (from-to)1-11
Number of pages11
JournalBone
Volume93
DOIs
Publication statusPublished - Dec 1 2016

All Science Journal Classification (ASJC) codes

  • Endocrinology, Diabetes and Metabolism
  • Physiology
  • Histology

Fingerprint Dive into the research topics of 'Sphingosine-1-phosphate/S1PR2-mediated signaling triggers Smad1/5/8 phosphorylation and thereby induces Runx2 expression in osteoblasts'. Together they form a unique fingerprint.

  • Cite this