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Loss of matrilin 1 does not exacerbate the skeletal phenotype in a mouse model of multiple epiphyseal dysplasia caused by a Matn3 V194D mutation

OBJECTIVE: Mutations in matrilin 3 can result in multiple epiphyseal dysplasia (MED), a disease characterized by delayed and irregular bone growth and early-onset osteoarthritis. Although intracellular retention of the majority of mutant matrilin 3 was previously observed in a murine model of MED ca...

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Detalles Bibliográficos
Autores principales: Bell, Peter A, Piróg, Katarzyna A, Fresquet, Maryline, Thornton, David J, Boot-Handford, Raymond P, Briggs, Michael D
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Wiley Subscription Services, Inc., A Wiley Company 2012
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3374853/
https://www.ncbi.nlm.nih.gov/pubmed/22083516
http://dx.doi.org/10.1002/art.33486
Descripción
Sumario:OBJECTIVE: Mutations in matrilin 3 can result in multiple epiphyseal dysplasia (MED), a disease characterized by delayed and irregular bone growth and early-onset osteoarthritis. Although intracellular retention of the majority of mutant matrilin 3 was previously observed in a murine model of MED caused by a Matn3 V194D mutation, some mutant protein was secreted into the extracellular matrix. Thus, it was proposed that secretion of mutant matrilin 3 may be dependent on the formation of hetero-oligomers with matrilin 1. The aim of this study was to investigate the hypothesis that deletion of matrilin 1 would abolish the formation of matrilin 1/matrilin 3 hetero-oligomers, eliminate the secretion of mutant matrilin 3, and influence disease severity. METHODS: Mice with a Matn3 V194D mutation were crossed with Matn1-null mice, generating mice that were homozygous for V194D and null for matrilin 1. This novel mouse was used for in-depth phenotyping, while cartilage and chondrocytes were studied both histochemically and biochemically. RESULTS: Endochondral ossification was not disrupted any further in mice with a double V194D mutation compared with mice with a single mutation. A similar proportion of mutant matrilin 3 was present in the extracellular matrix, and the amount of retained mutant matrilin 3 was not noticeably increased. Retained mutant matrilin 3 formed disulfide-bonded aggregates and caused the co-retention of matrilin 1. CONCLUSION: We showed that secretion of matrilin 3 V194D mutant protein is not dependent on hetero-oligomerization with matrilin 1, and that the total ablation of matrilin 1 expression has no impact on disease severity in mice with MED. Mutant matrilin 3 oligomers form non-native disulfide-bonded aggregates through the misfolded A domain.