title: Loss of Type I Collagen Telopeptide Lysyl Hydroxylation Causes Musculoskeletal Abnormalities in a Zebrafish Model of Bruck Syndrome.
abstract: Bruck syndrome (BS) is a disorder characterized by joint flexion contractures and skeletal dysplasia that shows strong clinical overlap with the brittle bone disease osteogenesis imperfecta (OI). BS is caused by biallelic mutations in either the FKBP10 or the PLOD2 gene. PLOD2 encodes the lysyl hydroxylase 2 (LH2) enzyme, which is responsible for the hydroxylation of lysine residues in fibrillar collagen telopeptides. This hydroxylation directs crosslinking of collagen fibrils in the extracellular matrix, which is necessary to provide stability and tensile integrity to the collagen fibrils. To further elucidate the function of LH2 in vertebrate skeletal development, we created a zebrafish model harboring a homozygous plod2 nonsense mutation resulting in reduced telopeptide hydroxylation and crosslinking of bone type I collagen. Adult plod2 mutants present with a shortened body axis and severe skeletal abnormalities with evidence of bone fragility and fractures. The vertebral column of plod2 mutants is short and scoliotic with compressed vertebrae that show excessive bone formation at the vertebral end plates, and increased tissue mineral density in the vertebral centra. The muscle fibers of mutant zebrafish have a reduced diameter near the horizontal myoseptum. The endomysium, a layer of connective tissue ensheathing the individual muscle fibers, is enlarged. Transmission electron microscopy of mutant vertebral bone shows type I collagen fibrils that are less organized with loss of the typical plywood-like structure. In conclusion, plod2 mutant zebrafish show molecular and tissue abnormalities in the musculoskeletal system that are concordant with clinical findings in BS patients. Therefore, the plod2 zebrafish mutant is a promising model for the elucidation of the underlying pathogenetic mechanisms leading to BS and the development of novel therapeutic avenues in this syndrome. © 2016 American Society for Bone and Mineral Research.
authors.affiliation: Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium.
authors.forename: Charlotte
authors.initials: C
authors.lastname: Gistelinck
authors.affiliation: Biology Department, Ghent University, Ghent, Belgium.
authors.forename: Paul Eckhard
authors.initials: PE
authors.lastname: Witten
authors.affiliation: Biology Department, Ghent University, Ghent, Belgium.
authors.forename: Ann
authors.initials: A
authors.lastname: Huysseune
authors.affiliation: Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium.
authors.forename: Sofie
authors.initials: S
authors.lastname: Symoens
authors.affiliation: Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium.
authors.forename: Fransiska
authors.initials: F
authors.lastname: Malfait
authors.affiliation: Biology Department, Ghent University, Ghent, Belgium.
authors.forename: Daria
authors.initials: D
authors.lastname: Larionova
authors.affiliation: Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium.
authors.forename: Pascal
authors.initials: P
authors.lastname: Simoens
authors.affiliation: Center for X-ray Tomography of Ghent University (UGCT), Department of Physics and Astronomy, Ghent University, Ghent, Belgium.
authors.forename: Manuel
authors.initials: M
authors.lastname: Dierick
authors.affiliation: Center for X-ray Tomography of Ghent University (UGCT), Department of Physics and Astronomy, Ghent University, Ghent, Belgium.
authors.forename: Luc
authors.initials: L
authors.lastname: Van Hoorebeke
authors.affiliation: Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium.
authors.forename: Anne
authors.initials: A
authors.lastname: De Paepe
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: Ronald Y
authors.initials: RY
authors.lastname: Kwon
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: MaryAnn
authors.initials: M
authors.lastname: Weis
authors.affiliation: Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
authors.forename: David R
authors.initials: DR
authors.lastname: Eyre
authors.affiliation: Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium.
authors.forename: Andy
authors.initials: A
authors.lastname: Willaert
authors.affiliation: Center for Medical Genetics Ghent, Ghent University, Ghent, Belgium.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Coucke
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001176:Arthrogryposis / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D001842:Bone and Bones / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000473:pathology; D002113:Calcification, Physiologic; D020134:Catalytic Domain; D018389:Codon, Nonsense / Q000235:genetics; D024042:Collagen Type I / Q000378:metabolism*; D017124:Conserved Sequence / Q000235:genetics; D003432:Cross-Linking Reagents / Q000378:metabolism; D019143:Evolution, Molecular; D006900:Hydroxylation; D007814:Larva / Q000378:metabolism; D008239:Lysine / Q000378:metabolism*; D013058:Mass Spectrometry; D009139:Musculoskeletal Abnormalities / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D009672:Notochord / Q000473:pathology; D010013:Osteogenesis Imperfecta / Q000150:complications / Q000000981:diagnostic imaging / Q000378:metabolism / Q000473:pathology*; D010455:Peptides / Q000378:metabolism*; D010641:Phenotype; D055114:X-Ray Microtomography; D015027:Zebrafish / Q000378:metabolism*; D029961:Zebrafish Proteins / Q000235:genetics
chemical_list: D018389:Codon, Nonsense; D024042:Collagen Type I; D003432:Cross-Linking Reagents; D010455:Peptides; D029961:Zebrafish Proteins; C052929:collagen type I trimeric cross-linked peptide; D008239:Lysine
keywords: BRUCK SYNDROME; COLLAGEN; LYSYL HYDROXYLASE 2; OSTEOGENESIS IMPERFECTA; PLOD2