Exp Mol Med.  2015 Jan;47(1):e128. 10.1038/emm.2014.95.

Fucoidan promotes osteoblast differentiation via JNK- and ERK-dependent BMP2-Smad 1/5/8 signaling in human mesenchymal stem cells

• Kim BS
• Kang HJ
• Park JY
• Lee J

• KMID: 2155393
• DOI: http://doi.org/10.1038/emm.2014.95

Abstract

Fucoidan has attracted attention as a potential drug because of its biological activities, which include osteogenesis. However, the molecular mechanisms involved in the osteogenic activity of fucoidan in human alveolar bone marrow-derived mesenchymal stem cells (hABM-MSCs) remain largely unknown. We investigated the action of fucoidan on osteoblast differentiation in hABM-MSCs and its impact on signaling pathways. Its effect on proliferation was determined using the crystal violet staining assay. Osteoblast differentiation was evaluated based on alkaline phosphatase (ALP) activity and the mRNA expression of multiple osteoblast markers. Calcium accumulation was determined by Alizarin red S staining. We found that fucoidan induced hABM-MSC proliferation. It also significantly increased ALP activity, calcium accumulation and the expression of osteoblast-specific genes, such as ALP, runt-related transcription factor 2, type I collagen-alpha 1 and osteocalcin. Moreover, fucoidan induced the expression of bone morphogenetic protein 2 (BMP2) and stimulated the activation of extracellular signal-related kinase (ERK), c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase by increasing phosphorylation. However, the effect of fucoidan on osteogenic differentiation was inhibited by specific inhibitors of ERK (PD98059) and JNK (SP600125) but not p38 (SB203580). Fucoidan enhanced BMP2 expression and Smad 1/5/8, ERK and JNK phosphorylation. Moreover, the effect of fucoidan on osteoblast differentiation was diminished by BMP2 knockdown. These results indicate that fucoidan induces osteoblast differentiation through BMP2-Smad 1/5/8 signaling by activating ERK and JNK, elucidating the molecular basis of the osteogenic effects of fucoidan in hABM-MSCs.

MeSH Terms

Bone Morphogenetic Protein 2/genetics/*metabolism
Calcium/metabolism
Cell Differentiation/drug effects
Cell Proliferation/drug effects
Cells, Cultured
Dose-Response Relationship, Drug
Extracellular Signal-Regulated MAP Kinases/*metabolism
Gene Expression Regulation/drug effects
Gene Knockdown Techniques
Humans
JNK Mitogen-Activated Protein Kinases/*metabolism
Mesenchymal Stromal Cells/cytology/*drug effects/*metabolism
Osteoblasts/cytology/drug effects/metabolism
Osteogenesis/drug effects
Phosphorylation
Polysaccharides/*pharmacology
Protein Kinase Inhibitors/pharmacology
RNA, Messenger/genetics
Signal Transduction/*drug effects
Smad Proteins/*metabolism
Bone Morphogenetic Protein 2
Calcium
Extracellular Signal-Regulated MAP Kinases
JNK Mitogen-Activated Protein Kinases
Polysaccharides
Protein Kinase Inhibitors
RNA, Messenger
Smad Proteins