Fermented Oyster Extract Promotes Osteoblast Differentiation by Activating the Wnt/β-Catenin Signaling Pathway, Leading to Bone Formation

• Published in: Biomolecules
• Main Authors: Ilandarage Menu Neelaka Molagoda, Wisurumuni Arachchilage Hasitha Maduranga Karunarathne, Yung Hyun Choi, Eui Kyun Park, You-Jin Jeon, Bae-Jin Lee, Chang-Hee Kang, Gi-Young Kim
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2019
• Subjects: crassostrea gigas; oyster; bone formation; mineralization; wnt/β-catenin; Microbiology; QR1-502; Pacific; Crassostrea gigas; Pacific oyster
• Online Access: https://doi.org/10.3390/biom9110711; https://doaj.org/article/6ed0e3ed30c6415a81896ce2c451d126

The Pacific oyster, Crassostrea gigas , is well-known as a nutritious food. Recently, we revealed that fermented extract of C. gigas (FO) inhibited ovariectomy-induced osteoporosis, resulting from suppression of osteoclastogenesis. However, since the beneficial effect of FO on osteogenesis is poorly understood, it was examined in mouse preosteoblast MC3T3-E1 cells, human osteosarcoma MG-63 osteoblast-like cells, and zebrafish larvae in this study. We found that FO increased mitochondrial activity from days 1 to 7; however, total cell number of MC3T3-E1 cells gradually decreased without any change in cell viability, which suggests that FO stimulates the differentiation of MC3T3-E1 cells. FO also promoted the expression of osteoblast marker genes, including runt-related transcription factor 2 (mRUNX2) , alkaline phosphatase (mALP) , collagen type I α1 (mCol1α1) , osteocalcin (mOCN) , osterix (mOSX) , bone morphogenetic protein 2 (mBMP2) , and mBMP4 in MC3T3-E1 cells accompanied by a significant increase in ALP activity. FO also increased nuclear translocation of RUNX2 and OSX transcription factors, ALP activity, and calcification in vitro along with the upregulated expression of osteoblast-specific marker proteins such as RUNX2, ALP, Col1α1, OCN, OSX, and BMP4. Additionally, FO enhanced bone mineralization (calcein intensity) in zebrafish larvae at 9 days post-fertilization comparable to that in the β-glycerophosphate (GP)-treated group. All the tested osteoblast marker genes, including zRUNX2a , zRUNX2b , zALP , zCol1a1 , zOCN , zBMP2 , and zBMP4 , were also remarkably upregulated in the zebrafish larvae in response to FO. It also promoted tail fin regeneration in adult zebrafish as same as the GP-treated groups. Furthermore, not only FO positively regulate β-catenin expression and Wnt/β-catenin luciferase activity, but pretreatment with a Wnt/β-catenin inhibitor (FH535) also significantly decreased FO-mediated bone mineralization in zebrafish larvae, which indicates that FO-induced osteogenesis depends on the ...