Mechanism involved in enhancement of osteoblast differentiation by hyaluronic acid

Michinao Kawano, Wataru Ariyoshi, Kenjiro Iwanaga, Toshinori Okinaga, Manabu Habu, Izumi Yoshioka, Kazuhiro Tominaga, Tatsuji Nishihara

Research output: Contribution to journalArticle

42 Citations (Scopus)

Abstract

Objectives: Bone morphogenetic protein-2 (BMP-2) is expected to be utilized to fill bone defects and promote healing of fractures. However, it is unable to generate an adequate clinical response for use in bone regeneration. Recently, it was reported that glycosaminoglycans, including heparin, heparan sulfate, keratan sulfate, dermatan sulfate, chondroitin-4-sulfate, chondroitin-6-sulfate, and hyaluronic acid (HA), regulate BMP-2 activity, though the mechanism by which HA regulates osteogenic activities has not been fully elucidated. The aim of this study was to investigate the effects of HA on osteoblast differentiation induced by BMP-2. Materials and methods: Monolayer cultures of osteoblastic lineage MG63 cells were incubated with BMP-2 and HA for various time periods. To determine osteoblastic differentiation, alkaline phosphatase (ALP) activity in the cell lysates was quantified. Phosphorylation of Smad 1/5/8, p38, and ERK proteins was determined by Western blot analysis. To elucidate the nuclear translocation of phosphorylated Smad 1/5/8, stimulated cells were subjected to immunofluorescence microscopy. To further elucidate the role of HA in enhancement of BMP-2-induced Smad signaling, mRNA expressions of the BMP-2 receptor antagonists noggin and follistatin were detected using real-time RT-PCR. Results: BMP-2-induced ALP activation, Smad 1/5/8 phosphorylation, and nuclear translocation were up-regulated when MG63 cells were cultured with both BMP-2 and HA. Western blot analysis revealed that phosphorylation of ERK protein was diminished by HA. Furthermore, the mRNA expressions of noggin and follistatin induced by BMP-2 were preferentially blocked by HA. Conclusions: These results indicate that HA enhanced BMP-2 induces osteoblastic differentiation in MG63 cells via down-regulation of BMP-2 antagonists and ERK phosphorylation.

Original languageEnglish
Pages (from-to)575-580
Number of pages6
JournalBiochemical and biophysical research communications
Volume405
Issue number4
DOIs
Publication statusPublished - 2011 Feb 25
Externally publishedYes

Keywords

  • ALP
  • BMP-2
  • Hyaluronic acid
  • MAPK
  • Osteoblast
  • Smad

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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