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Zappa F, Intartaglia D, Guarino AM, De Cegli R, Wilson C, Salierno FG, Polishchuk E, Sorrentino NC, Conte I, De Matteis MA. Role of trafficking protein particle complex 2 in medaka development. Traffic 2024; 25:e12924. [PMID: 37963679 DOI: 10.1111/tra.12924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/16/2023] [Accepted: 10/27/2023] [Indexed: 11/16/2023]
Abstract
The skeletal dysplasia spondyloepiphyseal dysplasia tarda (SEDT) is caused by mutations in the TRAPPC2 gene, which encodes Sedlin, a component of the trafficking protein particle (TRAPP) complex that we have shown previously to be required for the export of type II collagen (Col2) from the endoplasmic reticulum. No vertebrate model for SEDT has been generated thus far. To address this gap, we generated a Sedlin knockout animal by mutating the orthologous TRAPPC2 gene (olSedl) of Oryzias latipes (medaka) fish. OlSedl deficiency leads to embryonic defects, short size, diminished skeletal ossification and altered Col2 production and secretion, resembling human defects observed in SEDT patients. Moreover, SEDT knock-out animals display photoreceptor degeneration and gut morphogenesis defects, suggesting a key role for Sedlin in the development of these organs. Thus, by studying Sedlin function in vivo, we provide evidence for a mechanistic link between TRAPPC2-mediated membrane trafficking, Col2 export, and developmental disorders.
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Affiliation(s)
- Francesca Zappa
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
| | - Daniela Intartaglia
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
| | - Andrea M Guarino
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | - Rossella De Cegli
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
| | - Cathal Wilson
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
| | | | - Elena Polishchuk
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
| | - Nicolina Cristina Sorrentino
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
- Department of Clinical Medicine and Surgery, University of Naples Federico II, Naples, Italy
| | - Ivan Conte
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
- Department of Biology, University of Naples Federico II, Naples, Italy
| | - Maria Antonietta De Matteis
- Telethon Institute of Genetics and Medicine, TIGEM, Pozzuoli (Naples), Italy
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, Naples, Italy
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Tan Z, Kong M, Wen S, Tsang KY, Niu B, Hartmann C, Chan D, Hui CC, Cheah KSE. IRX3 and IRX5 Inhibit Adipogenic Differentiation of Hypertrophic Chondrocytes and Promote Osteogenesis. J Bone Miner Res 2020; 35:2444-2457. [PMID: 32662900 DOI: 10.1002/jbmr.4132] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/19/2020] [Accepted: 07/14/2020] [Indexed: 12/12/2022]
Abstract
Maintaining the correct proportions of different cell types in the bone marrow is critical for bone function. Hypertrophic chondrocytes (HCs) and osteoblasts are a lineage continuum with a minor contribution to adipocytes, but the regulatory network is unclear. Mutations in transcription factors, IRX3 and IRX5, result in skeletal patterning defects in humans and mice. We found coexpression of Irx3 and Irx5 in late-stage HCs and osteoblasts in cortical and trabecular bone. Irx3 and Irx5 null mutants display severe bone deficiency in newborn and adult stages. Quantitative analyses of bone with different combinations of functional alleles of Irx3 and Irx5 suggest these two factors function in a dosage-dependent manner. In Irx3 and Irx5 nulls, the amount of bone marrow adipocytes was increased. In Irx5 nulls, lineage tracing revealed that removal of Irx3 specifically in HCs exacerbated reduction of HC-derived osteoblasts and increased the frequency of HC-derived marrow adipocytes. β-catenin loss of function and gain of function specifically in HCs affects the expression of Irx3 and Irx5, suggesting IRX3 and IRX5 function downstream of WNT signaling. Our study shows that IRX3 and IRX5 regulate fate decisions in the transition of HCs to osteoblasts and to marrow adipocytes, implicating their potential roles in human skeletal homeostasis and disorders.
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Affiliation(s)
- Zhijia Tan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, HKSAR, China
| | - Mingpeng Kong
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, HKSAR, China
| | - Songjia Wen
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, HKSAR, China
| | - Kwok Yeung Tsang
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, HKSAR, China
| | - Ben Niu
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, HKSAR, China
| | - Christine Hartmann
- Institute of Musculoskeletal Medicine, Department of Bone and Skeletal Research, Faculty of Medicine, University of Münster, Münster, Germany
| | - Danny Chan
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, HKSAR, China
| | - Chi-Chung Hui
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children and Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Kathryn S E Cheah
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pok Fu Lam, Hong Kong, HKSAR, China
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3
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Struck AK, Dierks C, Braun M, Hellige M, Wagner A, Oelmaier B, Beineke A, Metzger J, Distl O. A recessive lethal chondrodysplasia in a miniature zebu family results from an insertion affecting the chondroitin sulfat domain of aggrecan. BMC Genet 2018; 19:91. [PMID: 30305023 PMCID: PMC6180608 DOI: 10.1186/s12863-018-0678-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 09/23/2018] [Indexed: 12/27/2022] Open
Abstract
Background Congenital skeletal malformations represent a heterogeneous group of disorders affecting bone and cartilage development. In cattle, particular chondrodysplastic forms have been identified in several miniature breeds. In this study, a phenotypic characterization was performed of an affected Miniature Zebu calf using computed tomography, necropsy and histopathological examinations, whole genome sequencing of the case and its parents on an Illumina NextSeq 500 in 2 × 150 bp paired-end mode and validation using Sanger sequencing and a Kompetitive Allele Specific PCR assay. Samples from the family of an affected Miniature Zebu with bulldog syndrome including parents and siblings, 42 healthy Miniature Zebu not related with members of the herd and 88 individuals from eight different taurine cattle breeds were available for validation. Results A bulldog-like Miniature Zebu calf showing a large bulging head, a short and compressed body and extremely short and stocky limbs was delivered after a fetotomy. Computed tomography and necropsy revealed severe craniofacial abnormalities including a shortening of the ventral nasal conchae, a cleft hard palate, rotated limbs as well as malformed and fused vertebrae and ribs. Histopathologic examination showed a disorganization of the physeal cartilage with disorderly arranged chondrocytes in columns and a multifocal closed epiphyseal plate. Whole-genome sequencing of this malformed Miniature Zebu calf, its dam and sire and subsequent comparative sequence analysis revealed a one base pair insertion (ACAN:c.5686insC) located within the cartilage development gene aggrecan (ACAN) exclusively homozygous in the affected calf and heterozygous in its parents. This variant was predicted to cause a frameshift (p.Val1898fsTer9) and thus a truncation of the chondroitin sulfate domain as well as a loss of the C-terminal globular domain of ACAN. It perfectly co-segregated with the lethal bulldog syndrome in Miniature Zebus. Conclusions We found a novel mutation in ACAN causing a recessive lethal chondrodysplasia in Miniature Zebu cattle. A diagnostic test for this mutation is now available for Miniature Zebu breeders preventing further cases of bulldog syndrome by targeted matings. To the authors’ best knowledge, this is the first case of a Miniature Zebu associated with an ACAN mutation. Electronic supplementary material The online version of this article (10.1186/s12863-018-0678-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Ann-Kathrin Struck
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Claudia Dierks
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Marina Braun
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Maren Hellige
- Clinic for Horses, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Anna Wagner
- Department of Pathology, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | | | - Andreas Beineke
- Department of Pathology, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Julia Metzger
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, 30559, Hannover, Germany
| | - Ottmar Distl
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, 30559, Hannover, Germany.
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Wang C, Tan Z, Niu B, Tsang KY, Tai A, Chan WCW, Lo RLK, Leung KKH, Dung NWF, Itoh N, Zhang MQ, Chan D, Cheah KSE. Inhibiting the integrated stress response pathway prevents aberrant chondrocyte differentiation thereby alleviating chondrodysplasia. eLife 2018; 7:37673. [PMID: 30024379 PMCID: PMC6053305 DOI: 10.7554/elife.37673] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 07/05/2018] [Indexed: 12/16/2022] Open
Abstract
The integrated stress response (ISR) is activated by diverse forms of cellular stress, including endoplasmic reticulum (ER) stress, and is associated with diseases. However, the molecular mechanism(s) whereby the ISR impacts on differentiation is incompletely understood. Here, we exploited a mouse model of Metaphyseal Chondrodysplasia type Schmid (MCDS) to provide insight into the impact of the ISR on cell fate. We show the protein kinase RNA-like ER kinase (PERK) pathway that mediates preferential synthesis of ATF4 and CHOP, dominates in causing dysplasia by reverting chondrocyte differentiation via ATF4-directed transactivation of Sox9. Chondrocyte survival is enabled, cell autonomously, by CHOP and dual CHOP-ATF4 transactivation of Fgf21. Treatment of mutant mice with a chemical inhibitor of PERK signaling prevents the differentiation defects and ameliorates chondrodysplasia. By preventing aberrant differentiation, titrated inhibition of the ISR emerges as a rationale therapeutic strategy for stress-induced skeletal disorders.
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Affiliation(s)
- Cheng Wang
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Zhijia Tan
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Ben Niu
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Kwok Yeung Tsang
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Andrew Tai
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Wilson C W Chan
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Rebecca L K Lo
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Keith K H Leung
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Nelson W F Dung
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
| | - Nobuyuki Itoh
- Graduate School of Pharmaceutical Sciences, University of Kyoto, Kyoto, Japan
| | - Michael Q Zhang
- Department of Biological Sciences, Center for Systems Biology, The University of Texas at Dallas, Richardson, United States.,MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, Tsinghua University, Beijing, China
| | - Danny Chan
- School of Biomedical Sciences, University of Hong Kong, Hong Kong, China
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5
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Tan Z, Niu B, Tsang KY, Melhado IG, Ohba S, He X, Huang Y, Wang C, McMahon AP, Jauch R, Chan D, Zhang MQ, Cheah KSE. Synergistic co-regulation and competition by a SOX9-GLI-FOXA phasic transcriptional network coordinate chondrocyte differentiation transitions. PLoS Genet 2018; 14:e1007346. [PMID: 29659575 PMCID: PMC5919691 DOI: 10.1371/journal.pgen.1007346] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 04/26/2018] [Accepted: 03/29/2018] [Indexed: 11/18/2022] Open
Abstract
The growth plate mediates bone growth where SOX9 and GLI factors control chondrocyte proliferation, differentiation and entry into hypertrophy. FOXA factors regulate hypertrophic chondrocyte maturation. How these factors integrate into a Gene Regulatory Network (GRN) controlling these differentiation transitions is incompletely understood. We adopted a genome-wide whole tissue approach to establish a Growth Plate Differential Gene Expression Library (GP-DGEL) for fractionated proliferating, pre-hypertrophic, early and late hypertrophic chondrocytes, as an overarching resource for discovery of pathways and disease candidates. De novo motif discovery revealed the enrichment of SOX9 and GLI binding sites in the genes preferentially expressed in proliferating and prehypertrophic chondrocytes, suggesting the potential cooperation between SOX9 and GLI proteins. We integrated the analyses of the transcriptome, SOX9, GLI1 and GLI3 ChIP-seq datasets, with functional validation by transactivation assays and mouse mutants. We identified new SOX9 targets and showed SOX9-GLI directly and cooperatively regulate many genes such as Trps1, Sox9, Sox5, Sox6, Col2a1, Ptch1, Gli1 and Gli2. Further, FOXA2 competes with SOX9 for the transactivation of target genes. The data support a model of SOX9-GLI-FOXA phasic GRN in chondrocyte development. Together, SOX9-GLI auto-regulate and cooperate to activate and repress genes in proliferating chondrocytes. Upon hypertrophy, FOXA competes with SOX9, and control toward terminal differentiation passes to FOXA, RUNX, AP1 and MEF2 factors. In the development of the mammalian growth plate, while several transcription factors are individually well known for their key roles in regulating phases of chondrocyte differentiation, there is little information on how they interact and cooperate with each other. We took an unbiased genome wide approach to identify the transcription factors and signaling pathways that play dominant roles in the chondrocyte differentiation cascade. We developed a searchable library of differentially expressed genes, GP-DGEL, which has fine spatial resolution and global transcriptomic coverage for discovery of processes, pathways and disease candidates. Our work identifies a novel regulatory mechanism that integrates the action of three transcription factors, SOX9, GLI and FOXA. SOX9-GLI auto-regulate and cooperate to activate and repress genes in proliferating chondrocytes. Upon entry into prehypertrophy, FOXA competes with SOX9, and control of hypertrophy passes to FOXA, RUNX, AP1 and MEF2 factors.
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Affiliation(s)
- Zhijia Tan
- School of Biomedical Sciences, LKS Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong
| | - Ben Niu
- School of Biomedical Sciences, LKS Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong
| | - Kwok Yeung Tsang
- School of Biomedical Sciences, LKS Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong
| | - Ian G. Melhado
- School of Biomedical Sciences, LKS Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong
| | - Shinsuke Ohba
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, W.M. Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - Xinjun He
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, W.M. Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - Yongheng Huang
- Genome Regulation Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China
| | - Cheng Wang
- School of Biomedical Sciences, LKS Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong
| | - Andrew P. McMahon
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, W.M. Keck School of Medicine of the University of Southern California, Los Angeles, California, United States of America
| | - Ralf Jauch
- Genome Regulation Laboratory, Guangzhou Institutes of Biomedicine and Health, Guangzhou, China
| | - Danny Chan
- School of Biomedical Sciences, LKS Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong
| | - Michael Q. Zhang
- Department of Biological Sciences, Center for Systems Biology, The University of Texas at Dallas, Dallas, Texas, United States of America
- MOE Key Laboratory of Bioinformatics, Center for Synthetic and Systems Biology, TNLIST, Tsinghua University, Beijing, China
| | - Kathryn S. E. Cheah
- School of Biomedical Sciences, LKS Faculty of Medicine, the University of Hong Kong, Pokfulam, Hong Kong
- * E-mail:
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Gibson BG, Briggs MD. The aggrecanopathies; an evolving phenotypic spectrum of human genetic skeletal diseases. Orphanet J Rare Dis 2016; 11:86. [PMID: 27353333 PMCID: PMC4924316 DOI: 10.1186/s13023-016-0459-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2016] [Accepted: 05/27/2016] [Indexed: 12/25/2022] Open
Abstract
The large chondroitin sulphated proteoglycan aggrecan (ACAN) is the most abundant non-collagenous protein in cartilage and is essential for its structure and function. Mutations in ACAN result in a broad phenotypic spectrum of non-lethal skeletal dysplasias including spondyloepimetaphyseal dysplasia, spondyloepiphyseal dysplasia, familial osteochondritis dissecans and various undefined short stature syndromes associated with accelerated bone maturation. However, very little is currently known about the disease pathways that underlie these aggrecanopathies, although they are likely to be a combination of haploinsufficiency and dominant-negative (neomorphic) mechanisms. This review discusses the known human and animal aggrecanopathies in the context of clinical presentation and potential disease mechanisms.
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Affiliation(s)
- Beth G Gibson
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, NE1 3BZ, UK
| | - Michael D Briggs
- Institute of Genetic Medicine, Newcastle University, Newcastle-upon-Tyne, NE1 3BZ, UK. .,International Centre for Life, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK.
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Cx43-Dependent Skeletal Phenotypes Are Mediated by Interactions between the Hapln1a-ECM and Sema3d during Fin Regeneration. PLoS One 2016; 11:e0148202. [PMID: 26828861 PMCID: PMC4734779 DOI: 10.1371/journal.pone.0148202] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 01/14/2016] [Indexed: 12/17/2022] Open
Abstract
Skeletal development is a tightly regulated process and requires proper communication between the cells for efficient exchange of information. Analysis of fin length mutants has revealed that the gap junction protein Connexin43 (Cx43) coordinates cell proliferation (growth) and joint formation (patterning) during zebrafish caudal fin regeneration. Previous studies have shown that the extra cellular matrix (ECM) protein Hyaluronan and Proteoglycan Link Protein1a (Hapln1a) is molecularly and functionally downstream of Cx43, and that hapln1a knockdown leads to reduction of the glycosaminoglycan hyaluronan. Here we find that the proteoglycan aggrecan is similarly reduced following Hapln1a knockdown. Notably, we demonstrate that both hyaluronan and aggrecan are required for growth and patterning. Moreover, we provide evidence that the Hapln1a-ECM stabilizes the secreted growth factor Semaphorin3d (Sema3d), which has been independently shown to mediate Cx43 dependent phenotypes during regeneration. Double knockdown of hapln1a and sema3d reveal synergistic interactions. Further, hapln1a knockdown phenotypes were rescued by Sema3d overexpression. Therefore, Hapln1a maintains the composition of specific components of the ECM, which appears to be required for the stabilization of at least one growth factor, Sema3d. We propose that the Hapln1a dependent ECM provides the required conditions for Sema3d stabilization and function. Interactions between the ECM and signaling molecules are complex and our study demonstrates the requirement for components of the Hapln1a-ECM for Sema3d signal transduction.
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Tsang KY, Tsang SW, Chan D, Cheah KSE. The chondrocytic journey in endochondral bone growth and skeletal dysplasia. ACTA ACUST UNITED AC 2015; 102:52-73. [PMID: 24677723 DOI: 10.1002/bdrc.21060] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2014] [Accepted: 02/23/2014] [Indexed: 12/29/2022]
Abstract
The endochondral bones of the skeleton develop from a cartilage template and grow via a process involving a cascade of chondrocyte differentiation steps culminating in formation of a growth plate and the replacement of cartilage by bone. This process of endochondral ossification, driven by the generation of chondrocytes and their subsequent proliferation, differentiation, and production of extracellular matrix constitute a journey, deviation from which inevitably disrupts bone growth and development, and is the basis of human skeletal dysplasias with a wide range of phenotypic severity, from perinatal lethality to progressively deforming. This highly coordinated journey of chondrocyte specification and fate determination is controlled by a myriad of intrinsic and extrinsic factors. SOX9 is the master transcription factor that, in concert with varying partners along the way, directs the different phases of the journey from mesenchymal condensation, chondrogenesis, differentiation, proliferation, and maturation. Extracellular signals, including bone morphogenetic proteins, wingless-related MMTV integration site (WNT), fibroblast growth factor, Indian hedgehog, and parathyroid hormone-related peptide, are all indispensable for growth plate chondrocytes to align and organize into the appropriate columnar architecture and controls their maturation and transition to hypertrophy. Chondrocyte hypertrophy, marked by dramatic volume increase in phases, is controlled by transcription factors SOX9, Runt-related transcription factor, and FOXA2. Hypertrophic chondrocytes mediate the cartilage to bone transition and concomitantly face a live-or-die situation, a subject of much debate. We review recent insights into the coordination of the phases of the chondrocyte journey, and highlight the need for a systems level understanding of the regulatory networks that will facilitate the development of therapeutic approaches for skeletal dysplasia.
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Affiliation(s)
- Kwok Yeung Tsang
- Department of Biochemistry, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong, China
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9
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Abstract
Growth plate is a specialized cartilaginous structure that mediates the longitudinal growth of skeletal bones. It consists of ordered zones of chondrocytes that secrete an extracellular matrix (ECM) composed of specific types of collagens and proteoglycans. Several heritable human skeletal dysplasias are caused by mutations in these ECM components and this review focuses on the roles of type II, IX, X, and XI collagens, aggrecan, matrilins, perlecan, and cartilage oligomeric matrix protein in the growth plate as deduced from human disease phenotypes and mouse models. Substantial advances have been achieved in deciphering the interaction networks and individual roles of these components in the construction of the growth plate ECM. Furthermore, ER stress and other cellular responses have been identified as key downstream effects of the ECM mutations contributing to abnormal growth plate development. The next challenge is to utilize the molecular level knowledge for the development of potential therapeutics.
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Affiliation(s)
- Johanna Myllyharju
- Oulu Center for Cell-Matrix Research, Biocenter Oulu and Faculty of Biochemistry and Molecular Medicine, University of Oulu, PO Box 5000, FIN-90014, Oulu, Finland,
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10
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Eames BF, Amores A, Yan YL, Postlethwait JH. Evolution of the osteoblast: skeletogenesis in gar and zebrafish. BMC Evol Biol 2012; 12:27. [PMID: 22390748 PMCID: PMC3314580 DOI: 10.1186/1471-2148-12-27] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 03/05/2012] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Although the vertebrate skeleton arose in the sea 500 million years ago, our understanding of the molecular fingerprints of chondrocytes and osteoblasts may be biased because it is informed mainly by research on land animals. In fact, the molecular fingerprint of teleost osteoblasts differs in key ways from that of tetrapods, but we do not know the origin of these novel gene functions. They either arose as neofunctionalization events after the teleost genome duplication (TGD), or they represent preserved ancestral functions that pre-date the TGD. Here, we provide evolutionary perspective to the molecular fingerprints of skeletal cells and assess the role of genome duplication in generating novel gene functions. We compared the molecular fingerprints of skeletogenic cells in two ray-finned fish: zebrafish (Danio rerio)--a teleost--and the spotted gar (Lepisosteus oculatus)--a "living fossil" representative of a lineage that diverged from the teleost lineage prior to the TGD (i.e., the teleost sister group). We analyzed developing embryos for expression of the structural collagen genes col1a2, col2a1, col10a1, and col11a2 in well-formed cartilage and bone, and studied expression of skeletal regulators, including the transcription factor genes sox9 and runx2, during mesenchymal condensation. RESULTS Results provided no evidence for the evolution of novel functions among gene duplicates in zebrafish compared to the gar outgroup, but our findings shed light on the evolution of the osteoblast. Zebrafish and gar chondrocytes both expressed col10a1 as they matured, but both species' osteoblasts also expressed col10a1, which tetrapod osteoblasts do not express. This novel finding, along with sox9 and col2a1 expression in developing osteoblasts of both zebrafish and gar, demonstrates that osteoblasts of both a teleost and a basally diverging ray-fin fish express components of the supposed chondrocyte molecular fingerprint. CONCLUSIONS Our surprising finding that the "chondrogenic" transcription factor sox9 is expressed in developing osteoblasts of both zebrafish and gar can help explain the expression of chondrocyte genes in osteoblasts of ray-finned fish. More broadly, our data suggest that the molecular fingerprint of the osteoblast, which largely is constrained among land animals, was not fixed during early vertebrate evolution.
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Affiliation(s)
- B Frank Eames
- Institute of Neuroscience, University of Oregon, Eugene, OR 97403-1254, USA.
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Tsang KY, Chan D, Bateman JF, Cheah KSE. In vivo cellular adaptation to ER stress: survival strategies with double-edged consequences. J Cell Sci 2010; 123:2145-54. [PMID: 20554893 DOI: 10.1242/jcs.068833] [Citation(s) in RCA: 99] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Disturbances to the balance of protein synthesis, folding and secretion in the endoplasmic reticulum (ER) induce stress and thereby the ER stress signaling (ERSS) response, which alleviates this stress. In this Commentary, we review the emerging idea that ER stress caused by abnormal physiological conditions and/or mutations in genes that encode client proteins of the ER is a key factor underlying different developmental processes and the pathology of diverse diseases, including diabetes, neurodegeneration and skeletal dysplasias. Recent studies in mouse models indicate that the effect of ERSS in vivo and the nature of the cellular strategies induced to ameliorate pathological ER stress are crucial factors in determining cell fate and clinical disease features. Importantly, ERSS can affect cellular proliferation and the differentiation program; cells that survive the stress can become 'reprogrammed' or dysfunctional. These cell-autonomous adaptation strategies can generate a spectrum of context-dependent cellular consequences, ranging from recovery to death. Secondary effects can include altered cell-extracellular-matrix interactions and non-cell-autonomous alteration of paracrine signaling, which contribute to the final phenotypic outcome. Recent reports showing that ER stress can be alleviated by chemical compounds suggest the potential for novel therapeutic approaches.
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Affiliation(s)
- Kwok Yeung Tsang
- Department of Biochemistry and Centre for Reproduction, Development and Growth, Li Ka Shing Faculty of Medicine, The University of Hong Kong, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
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The developmental roles of the extracellular matrix: beyond structure to regulation. Cell Tissue Res 2009; 339:93-110. [PMID: 19885678 DOI: 10.1007/s00441-009-0893-8] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 10/05/2009] [Indexed: 10/20/2022]
Abstract
Cells in multicellular organisms are surrounded by a complex three-dimensional macromolecular extracellular matrix (ECM). This matrix, traditionally thought to serve a structural function providing support and strength to cells within tissues, is increasingly being recognized as having pleiotropic effects in development and growth. Elucidation of the role that the ECM plays in developmental processes has been significantly advanced by studying the phenotypic and developmental consequences of specific genetic alterations of ECM components in the mouse. These studies have revealed the enormous contribution of the ECM to the regulation of key processes in morphogenesis and organogenesis, such as cell adhesion, proliferation, specification, migration, survival, and differentiation. The ECM interacts with signaling molecules and morphogens thereby modulating their activities. This review considers these advances in our understanding of the function of ECM proteins during development, extending beyond their structural capacity, to embrace their new roles in intercellular signaling.
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13
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The developmental roles of the extracellular matrix: beyond structure to regulation. Cell Tissue Res 2009. [DOI: 10.1007/s00441-009-0893-8 doi:dx.doi.org] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
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14
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Domowicz MS, Cortes M, Henry JG, Schwartz NB. Aggrecan modulation of growth plate morphogenesis. Dev Biol 2009; 329:242-57. [PMID: 19268444 DOI: 10.1016/j.ydbio.2009.02.024] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2008] [Revised: 02/02/2009] [Accepted: 02/20/2009] [Indexed: 10/21/2022]
Abstract
Chick and mouse embryos with heritable deficiencies of aggrecan exhibit severe dwarfism and premature death, demonstrating the essential involvement of aggrecan in development. The aggrecan-deficient nanomelic (nm) chick mutant E12 fully formed growth plate (GP) is devoid of matrix and exhibits markedly altered cytoarchitecture, proliferative capacity, and degree of cell death. While differentiation of chondroblasts to pre-hypertrophic chondrocytes (IHH expression) is normal up to E6, the extended periosteum expression pattern of PTCH (a downstream effector of IHH) indicates altered propagation of IHH signaling, as well as accelerated down-regulation of FGFR3 expression, decreased BrdU incorporation and higher levels of ERK phosphorylation, all indicating early effects on FGF signaling. By E7 reduced IHH expression and premature expression of COL10A1 foreshadow the acceleration of hypertrophy observed at E12. By E8, exacerbated co-expression of IHH and COL10A1 lead to delayed separation and establishment of the two GPs in each element. By E9, increased numbers of cells express P-SMAD1/5/8, indicating altered BMP signaling. These results indicate that the IHH, FGF and BMP signaling pathways are altered from the very beginning of GP formation in the absence of aggrecan, thereby inducing premature hypertrophic chondrocyte maturation, leading to the nanomelic long bone growth disorder.
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Affiliation(s)
- Miriam S Domowicz
- Departments of Pediatrics and Biochemistry and Molecular Biology, Committee on Developmental Biology, The University of Chicago, Chicago, IL 60637, USA
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15
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A mutation in Ihh that causes digit abnormalities alters its signalling capacity and range. Nature 2009; 458:1196-200. [PMID: 19252479 DOI: 10.1038/nature07862] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 02/12/2009] [Indexed: 11/08/2022]
Abstract
Brachydactyly type A1 (BDA1) was the first recorded disorder of the autosomal dominant Mendelian trait in humans, characterized by shortened or absent middle phalanges in digits. It is associated with heterozygous missense mutations in indian hedgehog (IHH). Hedgehog proteins are important morphogens for a wide range of developmental processes. The capacity and range of signalling is thought to be regulated by its interaction with the receptor PTCH1 and antagonist HIP1. Here we show that a BDA1 mutation (E95K) in Ihh impairs the interaction of IHH with PTCH1 and HIP1. This is consistent with a recent paper showing that BDA1 mutations cluster in a calcium-binding site essential for the interaction with its receptor and cell-surface partners. Furthermore, we show that in a mouse model that recapitulates the E95K mutation, there is a change in the potency and range of signalling. The mice have digit abnormalities consistent with the human disorder.
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16
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Patra D, Xing X, Davies S, Bryan J, Franz C, Hunziker EB, Sandell LJ. Site-1 protease is essential for endochondral bone formation in mice. ACTA ACUST UNITED AC 2007; 179:687-700. [PMID: 18025304 PMCID: PMC2080931 DOI: 10.1083/jcb.200708092] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Site-1 protease (S1P) has an essential function in the conversion of latent, membrane-bound transcription factors to their free, active form. In mammals, abundant expression of S1P in chondrocytes suggests an involvement in chondrocyte function. To determine the requirement of S1P in cartilage and bone development, we have created cartilage-specific S1P knockout mice (S1Pcko). S1Pcko mice exhibit chondrodysplasia and a complete lack of endochondral ossification even though Runx2 expression, Indian hedgehog signaling, and osteoblastogenesis is intact. However, there is a substantial increase in chondrocyte apoptosis in the cartilage of S1Pcko mice. Extraction of type II collagen is substantially lower from S1Pcko cartilage. In S1Pcko mice, the collagen network is disorganized and collagen becomes entrapped in chondrocytes. Ultrastructural analysis reveals that the endoplasmic reticulum (ER) in S1Pcko chondrocytes is engorged and fragmented in a manner characteristic of severe ER stress. These data suggest that S1P activity is necessary for a specialized ER stress response required by chondrocytes for the genesis of normal cartilage and thus endochondral ossification.
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Affiliation(s)
- Debabrata Patra
- Department of Orthopaedic Surgery, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO 63110, USA.
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17
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Kappen C, Neubüser A, Balling R, Finnell R. Molecular basis for skeletal variation: insights from developmental genetic studies in mice. BIRTH DEFECTS RESEARCH. PART B, DEVELOPMENTAL AND REPRODUCTIVE TOXICOLOGY 2007; 80:425-50. [PMID: 18157899 PMCID: PMC3938168 DOI: 10.1002/bdrb.20136] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Skeletal variations are common in humans, and potentially are caused by genetic as well as environmental factors. We here review molecular principles in skeletal development to develop a knowledge base of possible alterations that could explain variations in skeletal element number, shape or size. Environmental agents that induce variations, such as teratogens, likely interact with the molecular pathways that regulate skeletal development.
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Affiliation(s)
- C Kappen
- Center for Human Molecular Genetics, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA.
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18
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Cavanagh JAL, Tammen I, Windsor PA, Bateman JF, Savarirayan R, Nicholas FW, Raadsma HW. Bulldog dwarfism in Dexter cattle is caused by mutations in ACAN. Mamm Genome 2007; 18:808-14. [PMID: 17952705 DOI: 10.1007/s00335-007-9066-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2007] [Accepted: 08/13/2007] [Indexed: 11/27/2022]
Abstract
Bulldog dwarfism in Dexter cattle is one of the earliest single-locus disorders described in animals. Affected fetuses display extreme disproportionate dwarfism, reflecting abnormal cartilage development (chondrodysplasia). Typically, they die around the seventh month of gestation, precipitating a natural abortion. Heterozygotes show a milder form of dwarfism, most noticeably having shorter legs. Homozygosity mapping in candidate regions in a small Dexter pedigree suggested aggrecan (ACAN) as the most likely candidate gene. Mutation screening revealed a 4-bp insertion in exon 11 (2266_2267insGGCA) (called BD1 for diagnostic testing) and a second, rarer transition in exon 1 (-198C>T) (called BD2) that cosegregate with the disorder. In chondrocytes from cattle heterozygous for the insertion, mutant mRNA is subject to nonsense-mediated decay, showing only 8% of normal expression. Genotyping in Dexter families throughout the world shows a one-to-one correspondence between genotype and phenotype at this locus. The heterozygous and homozygous-affected Dexter cattle could prove invaluable as a model for human disorders caused by mutations in ACAN.
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Affiliation(s)
- Julie A L Cavanagh
- ReproGen, The University of Sydney, PMB3, Camden, New South Wales 2570, Australia.
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19
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Tsang KY, Chan D, Cheslett D, Chan WCW, So CL, Melhado IG, Chan TWY, Kwan KM, Hunziker EB, Yamada Y, Bateman JF, Cheung KMC, Cheah KSE. Surviving endoplasmic reticulum stress is coupled to altered chondrocyte differentiation and function. PLoS Biol 2007; 5:e44. [PMID: 17298185 PMCID: PMC1820825 DOI: 10.1371/journal.pbio.0050044] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2006] [Accepted: 12/13/2006] [Indexed: 11/19/2022] Open
Abstract
In protein folding and secretion disorders, activation of endoplasmic reticulum (ER) stress signaling (ERSS) protects cells, alleviating stress that would otherwise trigger apoptosis. Whether the stress-surviving cells resume normal function is not known. We studied the in vivo impact of ER stress in terminally differentiating hypertrophic chondrocytes (HCs) during endochondral bone formation. In transgenic mice expressing mutant collagen X as a consequence of a 13-base pair deletion in Col10a1 (13del), misfolded α1(X) chains accumulate in HCs and elicit ERSS. Histological and gene expression analyses showed that these chondrocytes survived ER stress, but terminal differentiation is interrupted, and endochondral bone formation is delayed, producing a chondrodysplasia phenotype. This altered differentiation involves cell-cycle re-entry, the re-expression of genes characteristic of a prehypertrophic-like state, and is cell-autonomous. Concomitantly, expression of Col10a1 and 13del mRNAs are reduced, and ER stress is alleviated. ERSS, abnormal chondrocyte differentiation, and altered growth plate architecture also occur in mice expressing mutant collagen II and aggrecan. Alteration of the differentiation program in chondrocytes expressing unfolded or misfolded proteins may be part of an adaptive response that facilitates survival and recovery from the ensuing ER stress. However, the altered differentiation disrupts the highly coordinated events of endochondral ossification culminating in chondrodysplasia. The assembly and folding of secreted proteins in the endoplasmic reticulum (ER) is exquisitely regulated by a complex mechanism that maintains an equilibrium between folded and unfolded proteins. Perturbation of this homeostasis induces ER stress, which, if not alleviated through ER stress signaling (ERSS), ultimately triggers cell death. Normal bone growth occurs through a highly coordinated differentiation program that yields specialized cartilage cells (chondrocytes); when this program is disrupted, chondrodysplasia, or malformed skeletons, can result. Chondrodysplasias caused by mutations that affect protein assembly and secretion are characterized by a disorganization of bony growth plates and distension of the ER. We tested whether these chondrodysplasia characteristics were linked to ERSS. By investigating the impact of ER stress on the cell fate of hypertrophic chondrocytes (HCs) in transgenic mice expressing mutations in collagen that prevent proper folding, we revealed a novel adaptive mechanism that helps alleviate the unfolded protein load. Instead of undergoing apoptosis, the HCs undergoing ER stress adapt, re-enter the cell cycle, and revert to a less-mature state in which expression of the mutant collagen is reduced. Our findings have broad implications for adaptive mechanisms to ER stress in vivo and for the pathophysiology underlying chondrodysplasias caused by mutations that impact on protein assembly and secretion. When subjected to ER stress (by expression of misfolded or unfolded proteins), hypertrophic chondrocytes undergo alterations to their developmental program that may be part of an adaptive response.
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Affiliation(s)
- Kwok Yeung Tsang
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Danny Chan
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Deborah Cheslett
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Wilson C. W Chan
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Chi Leong So
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Ian G Melhado
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Tori W. Y Chan
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Kin Ming Kwan
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Ernst B Hunziker
- ITI Research Institute for Dental and Skeletal Biology, University of Bern, Bern, Switzerland
| | - Yoshihiko Yamada
- Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, Bethesda, Maryland, United States of America
| | - John F Bateman
- Murdoch Childrens Research Institute, Royal Children's Hospital, Melbourne, Victoria, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Kenneth M. C Cheung
- Department of Orthopaedics and Traumatology, University of Hong Kong, Pokfulam, Hong Kong, China
| | - Kathryn S. E Cheah
- Department of Biochemistry, University of Hong Kong, Pokfulam, Hong Kong, China
- * To whom correspondence should be addressed. E-mail:
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20
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Ho MSP, Tsang KY, Lo RLK, Susic M, Mäkitie O, Chan TWY, Ng VCW, Sillence DO, Boot-Handford RP, Gibson G, Cheung KMC, Cole WG, Cheah KSE, Chan D. COL10A1 nonsense and frame-shift mutations have a gain-of-function effect on the growth plate in human and mouse metaphyseal chondrodysplasia type Schmid. Hum Mol Genet 2007; 16:1201-15. [PMID: 17403716 DOI: 10.1093/hmg/ddm067] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Missense, nonsense and frame-shift mutations in the collagen X gene (COL10A1) result in metaphyseal chondrodysplasia type Schmid (MCDS). Complete degradation of mutant COL10A1 mRNA by nonsense-mediated decay in human MCDS cartilage implicates haploinsufficiency in the pathogenesis for nonsense mutations in vivo. However, the mechanism is unclear in situations where the mutant mRNA persist. We show that nonsense/frame-shift mutations can elicit a gain-of-function effect, affecting chondrocyte differentiation in the growth plate. In an MCDS proband, heterozygous for a p.Y663X nonsense mutation, the growth plate cartilage contained 64% wild-type and 36% mutant mRNA and the hypertrophic zone was disorganized and expanded. The in vitro translated mutant collagen X chains, which are truncated, were misfolded, unable to assemble into trimers and interfered with the assembly of normal alpha1(X) chains into trimers. Unlike Col10a1 null mutants, transgenic mice (FCdel) bearing the mouse equivalent of a human MCDS p.P620fsX621 mutation, displayed typical characteristics of MCDS with disproportionate shortening of limbs and early onset coxa vara. In FCdel mice, the degree of expansion of the hypertrophic zones was transgene-dosage dependent, being most severe in mice homozygous for the transgene. Chondrocytes in the lower region of the expanded hypertrophic zone expressed markers uncharacteristic of hypertrophic chondrocytes, indicating that differentiation was disrupted. Misfolded FCdel alpha1(X) chains were retained within the endoplasmic reticulum of hypertrophic chondrocytes, activating the unfolded protein response. Our findings provide strong in vivo evidence for a gain-of-function effect that is linked to the activation of endoplasmic reticulum-stress response and altered chondrocyte differentiation, as a possible molecular pathogenesis for MCDS.
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Affiliation(s)
- Matthew S P Ho
- Department of Biochemistry, The University of Hong Kong, Pokfulam, Hong Kong, China
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21
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Aszódi A, Legate KR, Nakchbandi I, Fässler R. What mouse mutants teach us about extracellular matrix function. Annu Rev Cell Dev Biol 2006; 22:591-621. [PMID: 16824013 DOI: 10.1146/annurev.cellbio.22.010305.104258] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
For many years the extracellular matrix was viewed as a benign scaffold for arranging cells within connective tissues, but it is now being redefined as a dynamic, mobile, and flexible key player in defining cellular behavior. Gene targeting, transgene expression, and spontaneous mutations of extracellular matrix proteins in mice have greatly accelerated our mechanistic view of the structural and instructive functions of the extracellular matrix in developmental and regenerative processes. This review summarizes the phenotypes of genetic mouse models carrying mutations in extracellular matrix proteins, with specific emphasis on recent advances. The application of reverse genetics has demonstrated the multifunctionality of matrix proteins in a biological context and, in addition, has brought a novel perspective to the understanding of human pathologies.
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Affiliation(s)
- A Aszódi
- Department of Molecular Medicine, Max Planck Institute for Biochemistry, 82152 Martinsried, Germany.
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22
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Abstract
In the past decade, there has been an explosion of interest in hyaluronan, an often misunderstood, biochemically simple, yet functionally complex carbohydrate polymer that is a resident of many extracellular matrices. Previously thought of as a passive, space-filling component of the extracellular matrix, the so-called "goo" concept, hyaluronan has risen to a much higher regard in recent years, even being called "magic glue" in a recent perspective. Hyaluronan is likely to be the common thread in many morphogenetic processes, including condensation events and epithelial-to-mesenchymal transformation. Hyaluronan is comparatively unique as a component of the extracellular matrix as it is solely composed of carbohydrate. In order to truly understand this biopolymer, one must first understand its biosynthesis, then understand its uptake and turnover, then identify its binding proteins and receptors. Major advances have been made in all of these arenas within the past decade. Hyaluronan synthases, hyaluronidases, and the hyaladherins have been molecularly identified and cloned. Furthermore, many have now been inactivated, employing gene targeting strategies, to create mice deficient in the respective gene product function. Collectively, huge strides have been made in our understanding of the diverse biological functions for this fascinating molecule. Hyaluronan appeared in metazoans immediately prior to the arrival of the vertebrates, and may be required for the differentiation, development, and/or function of most cell lineages, structures, and tissues that we associate with vertebrates, such as the neural crest, the skeleton, including the teeth, skin, and hair, and the chambered heart. In this review, we will update the reader on the advances of the past decade and provide insight into those morphogenetic processes through which hyaluronan regulates vertebrate development.
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Affiliation(s)
- Andrew P Spicer
- Center for Extracellular Matrix Biology, Institute of Biosciences and Technology, Texas A&M University System Health Science Center, Houston, Texas, USA.
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23
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Garciadiego-Cázares D, Rosales C, Katoh M, Chimal-Monroy J. Coordination of chondrocyte differentiation and joint formation byα5β1 integrin in the developing appendicular skeleton. Development 2004; 131:4735-42. [PMID: 15329344 DOI: 10.1242/dev.01345] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The control point by which chondrocytes take the decision between the cartilage differentiation program or the joint formation program is unknown. Here, we have investigated the effect of α5β1 integrin inhibitors and bone morphogenetic protein (BMP) on joint formation. Blocking ofα5β1 integrin by specific antibodies or RGD peptide(arginine-glycine-aspartic acid) induced inhibition of pre-hypertrophic chondrocyte differentiation and ectopic joint formation between proliferating chondrocytes and hypertrophic chondrocytes. Ectopic joint expressed Wnt14,Gdf5, chordin, autotaxin, type I collagen and CD44, while expression of Indian hedgehog and type II collagen was downregulated in cartilage. Expression of these interzone markers confirmed that the new structure is a new joint being formed. In the presence of BMP7, inhibition of α5β1 integrin function still induced the formation of the ectopic joint between proliferating chondrocytes and hypertrophic chondrocytes. By contrast,misexpression of α5β1 integrin resulted in fusion of joints and formation of pre-hypertrophic chondrocytes. These facts indicate that the decision of which cell fate to make pre-joint or pre-hypertrophic is made on the basis of the presence or absence of α5β1 integrin on chondrocytes.
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Affiliation(s)
- David Garciadiego-Cázares
- Departamento de Biología Celular y Fisiología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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24
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Abstract
The proteoglycan aggregate of the cartilage is composed of aggrecan, link protein, and hyaluronan and forms a unique gel-like moiety that provides resistance to compression in joints and a foundational cartilage structure critical for growth plate formation. Aggrecan, a large chondroitin sulfate proteoglycan, is one of the major structural macromolecules in cartilage and binds both hyaluronan and link protein through its N-terminal domain G1. Link protein, a small glycoprotein, is homologous to the G1 domain of aggrecan. Mouse cartilage matrix deficiency (cmd) is caused by a functional null mutation of the aggrecan gene and is characterized by perinatal lethal dwarfism and craniofacial abnormalities. Link protein knockout mice show chondrodysplasia similar to but milder than cmd mice, suggesting a supporting role of link protein for the aggregate structure. Analysis of these mice revealed that the proteoglycan aggregate plays an important role in cartilage development and maintenance of cartilage tissue and may provide a clue to the identification of human genetic disorders caused by mutations in these genes.
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Affiliation(s)
- Hideto Watanabe
- Institute for Molecular Science of Medicine, Aichi Medical University, Yazako, Nagakute, Aichi, 480-1195, Japan.
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25
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Chambers MG, Kuffner T, Cowan SK, Cheah KSE, Mason RM. Expression of collagen and aggrecan genes in normal and osteoarthritic murine knee joints. Osteoarthritis Cartilage 2002; 10:51-61. [PMID: 11795983 DOI: 10.1053/joca.2001.0481] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The STR/ort mouse strain develops osteoarthritis (OA) of the medial tibial cartilage whilst CBA mice do not develop this disease. We investigated whether changes occur in the expression of genes encoding major extracellular matrix proteins in the connective tissue of the murine knee joint in OA. DESIGN Expression of the genes encoding collagens II (Col2alpha1), X (Col10alpha1), alpha2(XI) (Col11alpha2) and aggrecan (Agc) was detected in skeletally mature and immature male mice of the CBA and STR/ort strains by in situ hybridization. RESULTS Col2alpha1 was expressed by chondrocytes of the tibial and patella-femoral cartilage and by the meniscal cartilage in all young mice (4-9 weeks) but only in the patella-femoral cartilage in older mice of both strains (36-45 weeks). In contrast Col2alpha1 was expressed by growth plate chondrocytes of both species at all ages. Similarly, Col2alpha1 transcripts were detected in cruciate ligament cells in both strains at all ages. Col10alpha1 transcripts were detected in cruciate ligament cells in both strains at all ages. Col10alpha1 expression was evident in the hypertrophic chondrocytes in the growth plate of young CBA and STR mice, but was not active in these cells in mature animals. However, Col10alpha1 was transcribed in articular chondrocytes of the tibia, meniscal and patella-femoral cartilages of all ages, in normal and osteoarthritic mice. Transcripts were also present in ligament of some mature animals. Col11alpha2 followed a similar pattern of expression in CBA cartilages to Col2alpha1, being active in adult growth plate but generally inactive in adult articular cartilages. Young CBA and STR/ort mice expressed Col11alpha2 in articular cartilage and very strongly throughout the growth plate. Agc expression was detected in all articular cartilages at all ages in both strains. Interestingly, transcripts for all four genes were absent in tibial articular chondrocytes located close to osteoarthritic lesions in STR/ort mice, indicating that these cells are unable to synthesize matrix proteins. Adult STR/ort mice also showed evidence of tissue remodeling around the periphery of the knee joint. Cells in remodeling areas actively transcribed Col2alpha1, Col10alpha1, Col11alpha2 and Agc. CONCLUSION It is unlikely that OA develops in STR/ort mice because of failure to express major proteins in joint tissue. However, once lesions develop in articular cartilage neighbouring chondrocytes fail to express genes encoding several matrix proteins.
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Affiliation(s)
- M G Chambers
- Cell & Molecular Biology Section, Division of Biomedical Sciences, Imperial College School of Medicine, London, England
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26
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Selleri L, Depew MJ, Jacobs Y, Chanda SK, Tsang KY, Cheah KS, Rubenstein JL, O'Gorman S, Cleary ML. Requirement for Pbx1 in skeletal patterning and programming chondrocyte proliferation and differentiation. Development 2001; 128:3543-57. [PMID: 11566859 DOI: 10.1242/dev.128.18.3543] [Citation(s) in RCA: 203] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pbx1 and a subset of homeodomain proteins collaboratively bind DNA as higher-order molecular complexes with unknown consequences for mammalian development. Pbx1 contributions were investigated through characterization of Pbx1-deficient mice. Pbx1 mutants died at embryonic day 15/16 with severe hypoplasia or aplasia of multiple organs and widespread patterning defects of the axial and appendicular skeleton. An obligatory role for Pbx1 in limb axis patterning was apparent from malformations of proximal skeletal elements, but distal structures were unaffected. In addition to multiple rib and vertebral malformations, neural crest cell-derived skeletal structures of the second branchial arch were morphologically transformed into elements reminiscent of first arch-derived cartilages. Although the skeletal malformations did not phenocopy single or compound Hox gene defects, they were restricted to domains specified by Hox proteins bearing Pbx dimerization motifs and unaccompanied by alterations in Hox gene expression. In affected domains of limbs and ribs, chondrocyte proliferation was markedly diminished and there was a notable increase of hypertrophic chondrocytes, accompanied by premature ossification of bone. The pattern of expression of genes known to regulate chondrocyte differentiation was not perturbed in Pbx1-deficient cartilage at early days of embryonic skeletogenesis, however precocious expression of Col1a1, a marker of bone formation, was found. These studies demonstrate a role for Pbx1 in multiple developmental programs and reveal a novel function in co-ordinating the extent and/or timing of proliferation with terminal differentiation. This impacts on the rate of endochondral ossification and bone formation and suggests a mechanistic basis for most of the observed skeletal malformations.
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Affiliation(s)
- L Selleri
- Department of Pathology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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27
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Smits P, Li P, Mandel J, Zhang Z, Deng JM, Behringer RR, de Crombrugghe B, Lefebvre V. The transcription factors L-Sox5 and Sox6 are essential for cartilage formation. Dev Cell 2001; 1:277-90. [PMID: 11702786 DOI: 10.1016/s1534-5807(01)00003-x] [Citation(s) in RCA: 448] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
L-Sox5 and Sox6 are highly identical Sry-related transcription factors coexpressed in cartilage. Whereas Sox5 and Sox6 single null mice are born with mild skeletal abnormalities, Sox5; Sox6 double null fetuses die with a severe, generalized chondrodysplasia. In these double mutants, chondroblasts poorly differentiate. They express the genes for all essential cartilage extracellular matrix components at low or undetectable levels and initiate proliferation after a long delay. All cartilages are thus extracellular matrix deficient and remain rudimentary. While chondroblasts in the center of cartilages ultimately activate prehypertrophic chondrocyte markers, epiphyseal chondroblasts ectopically activate hypertrophic chondrocyte markers. Thick intramembranous bone collars develop, but the formation of cartilage growth plates and endochondral bones is disrupted. L-Sox5 and Sox6 are thus redundant, potent enhancers of chondroblast functions, thereby essential for endochondral skeleton formation.
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Affiliation(s)
- P Smits
- Department of Molecular Genetics, The University of Texas M.D. Anderson Cancer Center, Houston 77030, USA
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28
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Kiani C, Lee V, Cao L, Chen L, Wu Y, Zhang Y, Adams ME, Yang BB. Roles of aggrecan domains in biosynthesis, modification by glycosaminoglycans and product secretion. Biochem J 2001; 354:199-207. [PMID: 11171095 PMCID: PMC1221644 DOI: 10.1042/0264-6021:3540199] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aggrecan is a member of the chondroitin sulphate (CS) proteoglycan family, which also includes versican/PG-M, neurocan and brevican. Members of this family exhibit structural similarity: a G1 domain at the N-terminus and a G3 domain at the C-terminus, with a central sequence for modification by CS chains. A unique feature of aggrecan is the insertion of three additional domains, an inter-globular domain (IGD), a G2 domain and a keratan sulphate (KS) domain (sequence modified by KS chains), between the G1 domain and the CS domain (sequence modified by CS chains). The G1 and G3 domains have been implicated in product secretion, but G2, although structurally similar to the tandem repeats of G1, performs an unknown function. To define the functions of each aggrecan domain in product processing, we cloned and expressed these domains in various combinations in COS-7 cells. The results indicated that the G3 domain enhanced product secretion, alone or in combination with the KS or CS domain, and promoted glycosaminoglycan (GAG) chain attachment. Constructs containing the G1 domain were not secreted. Addition of a CS domain sequence to G1 reduced this inhibition, but GAG chain attachment was still decreased. The potential GAG chain attachment site in the IGD was occupied by GAGs, and IGD product was secreted efficiently. The KS domain was modified by GAG chains and secreted. Finally, the G2 domain was expressed but not secreted, and inhibited secretion of the IGD when expressed as an IGD-G2 combination.
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Affiliation(s)
- C Kiani
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 100 College Street, Toronto M5G 1L5, Canada
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Abstract
Major advances have been made in the last 10 years in the genetics of skeletogenesis. This has followed the general progress in our understanding of the genetic control of development in chicken and mouse and more recent advances in human genetics. This large field now encompasses three smaller but distinct fields of investigation. Those are skeleton patterning, cell differentiation in the skeleton, and cell function in the skeleton. This review focuses primarily on advances in understanding cell differentiation and cell function in the skeleton at the genetic level.
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Affiliation(s)
- G Karsenty
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
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