title: Peroxidase Enzymes Regulate Collagen Biosynthesis and Matrix Mineralization by Cultured Human Osteoblasts.
abstract: The early recruitment of inflammatory cells to sites of bone fracture and trauma is a critical determinant in successful fracture healing. Released by infiltrating inflammatory cells, myeloperoxidase (MPO) and eosinophil peroxidase (EPO) are heme-containing enzymes, whose functional involvement in bone repair has mainly been studied in the context of providing a mechanism for oxidative defense against invading microorganisms. We report here novel findings that show peroxidase enzymes have the capacity to stimulate osteoblastic cells to secrete collagen I protein and generate a mineralized extracellular matrix in vitro. Mechanistic studies conducted using cultured osteoblasts show that peroxidase enzymes stimulate collagen biosynthesis at a post-translational level in a prolyl hydroxylase-dependent manner, which does not require ascorbic acid. Our studies demonstrate that osteoblasts rapidly bind and internalize both MPO and EPO, and the catalytic activity of these peroxidase enzymes is essential to support collagen I biosynthesis and subsequent release of collagen by osteoblasts. We show that EPO is capable of regulating osteogenic gene expression and matrix mineralization in culture, suggesting that peroxidase enzymes may play an important role not only in normal bone repair, but also in the progression of pathological states where infiltrating inflammatory cells are known to deposit peroxidases.
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia. mark.denichilo@adelaide.edu.au.|TQEH, Basil Hetzel Research Institute, 28 Woodville Road, Woodville, SA, 5011, Australia. mark.denichilo@adelaide.edu.au.
authors.forename: Mark O
authors.identifier: http://orcid.org/0000-0001-9152-7569
authors.initials: MO
authors.lastname: DeNichilo
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia.
authors.forename: Alexandra J
authors.initials: AJ
authors.lastname: Shoubridge
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia.
authors.forename: Vasilios
authors.initials: V
authors.lastname: Panagopoulos
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia.
authors.forename: Vasilios
authors.initials: V
authors.lastname: Liapis
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia.
authors.forename: Aneta
authors.initials: A
authors.lastname: Zysk
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia.
authors.forename: Irene
authors.initials: I
authors.lastname: Zinonos
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia.
authors.forename: Shelley
authors.initials: S
authors.lastname: Hay
authors.affiliation: Discipline of Orthopaedics and Trauma, The University of Adelaide, Adelaide, Australia.
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Atkins
authors.affiliation: Discipline of Orthopaedics and Trauma, The University of Adelaide, Adelaide, Australia.
authors.forename: David M
authors.initials: DM
authors.lastname: Findlay
authors.affiliation: Breast Cancer Research Unit, Discipline of Surgery, The University of Adelaide, Adelaide, Australia.|Centre for Personalized Cancer Medicine, The University of Adelaide, Adelaide, Australia.
authors.forename: Andreas
authors.initials: A
authors.lastname: Evdokiou
mesh_terms: D019644:Arthroplasty, Replacement, Hip; D001205:Ascorbic Acid / Q000737:chemistry; D001842:Bone and Bones / Q000378:metabolism; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis*; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D047209:Eosinophil Peroxidase / Q000378:metabolism; D005109:Extracellular Matrix / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation; D015971:Gene Expression Regulation, Enzymologic; D006418:Heme / Q000737:chemistry; D006801:Humans; D007249:Inflammation; D010006:Osteoblasts / Q000201:enzymology*; D010544:Peroxidases / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000378:metabolism
chemical_list: D011994:Recombinant Proteins; D006418:Heme; D003094:Collagen; D047209:Eosinophil Peroxidase; D010544:Peroxidases; D001205:Ascorbic Acid
keywords: Collagen biosynthesis; Matrix mineralization; Osteoblasts; Peroxidase enzymes