Proteolytic processing of osteopontin by PHEX and accumulation of osteopontin fragments in Hyp mouse bone, the murine model of X-linked hypophosphatemia

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dc.contributor.authorBarros, Nilana Meza Tenório de [UNIFESP]
dc.contributor.authorHoac, Betty
dc.contributor.authorNeves, Raquel Leão [UNIFESP]
dc.contributor.authorAddison, William N.
dc.contributor.authorAssis, Diego Magno [UNIFESP]
dc.contributor.authorMurshed, Monzur
dc.contributor.authorCarmona, Adriana Karaoglanovic [UNIFESP]
dc.contributor.authorMcKee, Marc D.
dc.contributor.institutionUniversidade Federal de São Paulo (UNIFESP)
dc.contributor.institutionMcGill Univ
dc.contributor.institutionHarvard Univ
dc.date.accessioned2016-01-24T14:31:16Z
dc.date.available2016-01-24T14:31:16Z
dc.date.issued2013-03-01
dc.description.abstractX-linked hypophosphatemia (XLH/HYP)with renal phosphate wasting, hypophosphatemia, osteomalacia, and tooth abscessesis caused by mutations in the zinc-metallopeptidase PHEX gene (phosphate-regulating gene with homologies to endopeptidase on the X chromosome). PHEX is highly expressed by mineralized tissue cells. Inactivating mutations in PHEX lead to distal renal effects (implying accumulation of a secreted, circulating phosphaturic factor) and accumulation in bone and teeth of mineralization-inhibiting, acidic serine- and aspartate-rich motif (ASARM)-containing peptides, which are proteolytically derived from the mineral-binding matrix proteins of the SIBLING family (small, integrin-binding ligand N-linked glycoproteins). Although the latter observation suggests a local, direct matrix effect for PHEX, its physiologically relevant substrate protein(s) have not been identified. Here, we investigated two SIBLING proteins containing the ASARM motifosteopontin (OPN) and bone sialoprotein (BSP)as potential substrates for PHEX. Using cleavage assays, gel electrophoresis, and mass spectrometry, we report that OPN is a full-length protein substrate for PHEX. Degradation of OPN was essentially complete, including hydrolysis of the ASARM motif, resulting in only very small residual fragments. Western blotting of Hyp (the murine homolog of human XLH) mouse bone extracts having no PHEX activity clearly showed accumulation of an approximate to 35kDa OPN fragment that was not present in wild-type mouse bone. Immunohistochemistry and immunogold labeling (electron microscopy) for OPN in Hyp bone likewise showed an accumulation of OPN and/or its fragments compared with normal wild-type bone. Incubation of Hyp mouse bone extracts with PHEX resulted in the complete degradation of these fragments. in conclusion, these results identify full-length OPN and its fragments as novel, physiologically relevant substrates for PHEX, suggesting that accumulation of mineralization-inhibiting OPN fragments may contribute to the mineralization defect seen in the osteomalacic bone characteristic of XLH/HYP. (c) 2013 American Society for Bone and Mineral Research.en
dc.description.affiliationUniversidade Federal de São Paulo, Dept Biofis, BR-04039032 São Paulo, Brazil
dc.description.affiliationUniversidade Federal de São Paulo, Dept Ciencias Exatas & Terra, Diadema, Brazil
dc.description.affiliationMcGill Univ, Fac Dent, Montreal, PQ, Canada
dc.description.affiliationHarvard Univ, Sch Dent Med, Dept Oral Med Infect & Immun, Boston, MA 02115 USA
dc.description.affiliationMcGill Univ, Dept Med, Fac Med, Montreal, PQ, Canada
dc.description.affiliationMcGill Univ, Fac Med, Dept Anat & Cell Biol, Montreal, PQ, Canada
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Dept Biofis, BR-04039032 São Paulo, Brazil
dc.description.affiliationUnifespUniversidade Federal de São Paulo, Dept Ciencias Exatas & Terra, Diadema, Brazil
dc.description.sourceWeb of Science
dc.description.sponsorshipAlexion Pharmaceuticals
dc.description.sponsorshipCanadian Institutes of Health Research (CIHR)
dc.description.sponsorshipFonds de Recherche Quebec-Sante (FRQS) Network in Oral and Bone Health Research
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
dc.description.sponsorshipIDFAPESP: FAPESP-11/50495-0
dc.description.sponsorshipIDCNPq: CNPq-470806/2009-5
dc.format.extent688-699
dc.identifierhttp://dx.doi.org/10.1002/jbmr.1766
dc.identifier.citationJournal of Bone and Mineral Research. Hoboken: Wiley-Blackwell, v. 28, n. 3, p. 688-699, 2013.
dc.identifier.doi10.1002/jbmr.1766
dc.identifier.issn0884-0431
dc.identifier.urihttp://repositorio.unifesp.br/handle/11600/35987
dc.identifier.wosWOS:000315106300027
dc.language.isoeng
dc.publisherWiley-Blackwell
dc.relation.ispartofJournal of Bone and Mineral Research
dc.rightsinfo:eu-repo/semantics/openAccess
dc.rights.licensehttp://olabout.wiley.com/WileyCDA/Section/id-406071.html
dc.subjectOSTEOPONTINen
dc.subjectPHEXen
dc.subjectX-LINKED HYPOPHOSPHATEMIAen
dc.subjectMINERALIZATIONen
dc.subjectBONE ENZYMESen
dc.titleProteolytic processing of osteopontin by PHEX and accumulation of osteopontin fragments in Hyp mouse bone, the murine model of X-linked hypophosphatemiaen
dc.typeinfo:eu-repo/semantics/article
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