title: Extracellular matrix disruption is an early event in the pathogenesis of skeletal disease in mucopolysaccharidosis I.
abstract: Progressive skeletal and connective tissue disease represents a significant clinical burden in all of the mucopolysaccharidoses. Despite the introduction of enzyme replacement strategies for many of the mucopolysaccharidoses, symptomatology related to bone and joint disease appears to be recalcitrant to current therapies. In order to address these unmet medical needs a clearer understanding of skeletal and connective tissue disease pathogenesis is required. Historically the pathogenesis of the mucopolysaccharidoses has been assumed to directly relate to progressive storage of glycosaminoglycans. It is now apparent for many lysosomal storage disorders that more complex pathogenic mechanisms underlie patients' clinical symptoms. We have used proteomic and genome wide expression studies in the murine mucopolysaccharidosis I model to identify early pathogenic events occurring in micro-dissected growth plate tissue. Studies were conducted using 3 and 5-week-old mice thus representing a time at which no obvious morphological changes of bone or joints have taken place. An unbiased iTRAQ differential proteomic approach was used to identify candidates followed by validation with multiple reaction monitoring mass spectrometry and immunohistochemistry. These studies reveal significant decreases in six key structural and signaling extracellular matrix proteins; biglycan, fibromodulin, PRELP, type I collagen, lactotransferrin, and SERPINF1. Genome-wide expression studies in embryonic day 13.5 limb cartilage and 5 week growth plate cartilage followed by specific gene candidate qPCR studies in the 5week growth plate identified fourteen significantly deregulated mRNAs (Adamts12, Aspn, Chad, Col2a1, Col9a1, Hapln4, Lum, Matn1, Mmp3, Ogn, Omd, P4ha2, Prelp, and Rab32). The involvement of biglycan, PRELP and fibromodulin; all members of the small leucine repeat proteoglycan family is intriguing, as this protein family is implicated in the pathogenesis of late onset osteoarthritis. Taken as a whole, our data indicates that alteration of the extracellular matrix represents a very early event in the pathogenesis of the mucopolysaccharidoses and implies that biomechanical failure of chondro-osseous tissue may underlie progressive bone and joint disease symptoms. These findings have important therapeutic implications.
authors.affiliation: Department of Medical Genetics, University of British Columbia, 950 West 28 Avenue, Vancouver, British Columbia V5Z-4H4, Canada; The Child and Family Research Institute, University of British Columbia, 950 West 28 Avenue, Vancouver, British Columbia V5Z-4H4, Canada.
authors.forename: Jonathan M
authors.initials: JM
authors.lastname: Heppner
authors.affiliation: Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany; Cologne Center for Musculoskeletal Biomechanics, Medical Faculty, University of Cologne, Cologne, Germany.
authors.forename: Frank
authors.initials: F
authors.lastname: Zaucke
authors.affiliation: Department of Medical Genetics, University of British Columbia, 950 West 28 Avenue, Vancouver, British Columbia V5Z-4H4, Canada; The Child and Family Research Institute, University of British Columbia, 950 West 28 Avenue, Vancouver, British Columbia V5Z-4H4, Canada. Electronic address: lclarke@cfri.ca.
authors.forename: Lorne A
authors.initials: LA
authors.lastname: Clarke
mesh_terms: D000818:Animals; D058578:Biglycan / Q000378:metabolism; D001847:Bone Diseases / Q000209:etiology* / Q000378:metabolism*; D024042:Collagen Type I / Q000378:metabolism; D004195:Disease Models, Animal; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000378:metabolism; D005136:Eye Proteins / Q000378:metabolism; D000071235:Fibromodulin; D020869:Gene Expression Profiling; D006023:Glycoproteins / Q000378:metabolism; D006025:Glycosaminoglycans / Q000378:metabolism; D007150:Immunohistochemistry; D007781:Lactoferrin / Q000378:metabolism; D013058:Mass Spectrometry; D051379:Mice; D018345:Mice, Knockout; D008059:Mucopolysaccharidosis I / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000378:metabolism; D010003:Osteoarthritis / Q000209:etiology; D011509:Proteoglycans / Q000378:metabolism; D040901:Proteomics; D015843:Serpins / Q000378:metabolism; D000099174:Pigment Epithelium-Derived Factor
chemical_list: D058578:Biglycan; D024042:Collagen Type I; D016326:Extracellular Matrix Proteins; D005136:Eye Proteins; D000071235:Fibromodulin; D006023:Glycoproteins; D006025:Glycosaminoglycans; D007781:Lactoferrin; D009414:Nerve Growth Factors; D011509:Proteoglycans; D015843:Serpins; D000099174:Pigment Epithelium-Derived Factor; C546885:Bgn protein, mouse; C000604332:Fmod protein, mouse; C490748:Prelp protein, mouse
keywords: Arthritis; Extracellular matrix structural integrity; MPS I; MRM; SLRPs; iTRAQ