title: Osteocalcin Mediates Biomineralization during Osteogenic Maturation in Human Mesenchymal Stromal Cells.
abstract: There is a growing interest in cell therapies using mesenchymal stromal cells (MSCs) for repairing bone defects. MSCs have the ability to differentiate into osteoprogenitors and osteoblasts as well as to form calcified bone matrix. However, the molecular mechanisms governing mineralization during osteogenic differentiation remain unclear. Non-collagenous proteins in the extracellular matrix are believed to control different aspects of the mineralization. Since osteocalcin is the most abundant non-collagenous bone matrix protein, the purpose of this study is to investigate the roles of osteocalcin in mineral species production during osteogenesis of MSCs. Using Raman spectroscopy, we found that the maturation of mineral species was affected by osteocalcin expression level. After osteocalcin was knocked down, the mineral species maturation was delayed and total hydroxyapatite was lower than the control group. In addition, the expression of osteogenic marker genes, includingRUNX2, alkaline phosphatase, type I collagen, and osteonectin, was downregulated during osteogenic differentiation compared to the control group; whereas gene expression of osterix was upregulated after the knockdown. Together, osteocalcin plays an essential role for the maturation of mineral species and modulates osteogenic differentiation of MSCs. The results offer new insights into the enhancement of new bone formation, such as for the treatments of osteoporosis and fracture healing.
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei 11221, Taiwan. tsaoyutzu@gmail.com.|Division of Nephrology, Department of Medicine, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan 33004, Taiwan. tsaoyutzu@gmail.com.
authors.forename: Yu-Tzu
authors.initials: YT
authors.lastname: Tsao
authors.affiliation: Institute of Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan. hieiinuyasha@gmail.com.
authors.forename: Yi-Jeng
authors.initials: YJ
authors.lastname: Huang
authors.affiliation: Institute of Biophotonics, National Yang-Ming University, Taipei 11221, Taiwan. haohsiang.wu@gmail.com.
authors.forename: Hao-Hsiang
authors.initials: HH
authors.lastname: Wu
authors.affiliation: Stem Cell Research Center, National Yang-Ming University, Taipei 11221, Taiwan. yuan_01@hotmail.com.
authors.forename: Yu-An
authors.initials: YA
authors.lastname: Liu
authors.affiliation: Stem Cell Research Center, National Yang-Ming University, Taipei 11221, Taiwan. lyspub1@gmail.com.
authors.forename: Yi-Shiuan
authors.initials: YS
authors.lastname: Liu
authors.affiliation: Institute of Clinical Medicine, National Yang-Ming University, Taipei 11221, Taiwan. DAV47@tpech.gov.tw.|Stem Cell Research Center, National Yang-Ming University, Taipei 11221, Taiwan. DAV47@tpech.gov.tw.|Taipei City Hospital, Taipei 10341, Taiwan. DAV47@tpech.gov.tw.|Department of Medical Research, Taipei Veterans General Hospital, Taipei 11217, Taiwan. DAV47@tpech.gov.tw.|Department of Orthopaedics and Traumatology, Taipei Veterans General Hospital, Taipei 11217, Taiwan. DAV47@tpech.gov.tw.
authors.forename: Oscar K
authors.initials: OK
authors.lastname: Lee
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000880:Anthraquinones; D002113:Calcification, Physiologic / Q000235:genetics*; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D024042:Collagen Type I / Q000235:genetics / Q000378:metabolism; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics / Q000378:metabolism; D017886:Durapatite / Q000378:metabolism; D015870:Gene Expression; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D015675:Osteocalcin / Q000235:genetics* / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics*; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013059:Spectrum Analysis, Raman; D013194:Staining and Labeling / Q000379:methods
chemical_list: D000880:Anthraquinones; D024042:Collagen Type I; D050659:Core Binding Factor Alpha 1 Subunit; D015676:Osteonectin; C493709:RUNX2 protein, human; D015675:Osteocalcin; C010078:alizarin; D017886:Durapatite; D000469:Alkaline Phosphatase
keywords: Raman spectroscopy; hydroxyapatite; mesenchymal stromal cells (MSCs); mineralization; non-collagenous protein; osteocalcin; osteogenic differentiation