کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2828564 1162735 2013 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Age-related nanostructural and nanomechanical changes of individual human cartilage aggrecan monomers and their glycosaminoglycan side chains
موضوعات مرتبط
علوم زیستی و بیوفناوری بیوشیمی، ژنتیک و زیست شناسی مولکولی زیست شناسی مولکولی
پیش نمایش صفحه اول مقاله
Age-related nanostructural and nanomechanical changes of individual human cartilage aggrecan monomers and their glycosaminoglycan side chains
چکیده انگلیسی
The nanostructure and nanomechanical properties of aggrecan monomers extracted and purified from human articular cartilage from donors of different ages (newborn, 29 and 38 year old) were directly visualized and quantified via atomic force microscopy (AFM)-based imaging and force spectroscopy. AFM imaging enabled direct comparison of full length monomers at different ages. The higher proportion of aggrecan fragments observed in adult versus newborn populations is consistent with the cumulative proteolysis of aggrecan known to occur in vivo. The decreased dimensions of adult full length aggrecan (including core protein and glycosaminoglycan (GAG) chain trace length, end-to-end distance and extension ratio) reflect altered aggrecan biosynthesis. The demonstrably shorter GAG chains observed in adult full length aggrecan monomers, compared to newborn monomers, also reflects markedly altered biosynthesis with age. Direct visualization of aggrecan subjected to chondroitinase and/or keratanase treatment revealed conformational properties of aggrecan monomers associated with chondroitin sulfate (CS) and keratan sulfate (KS) GAG chains. Furthermore, compressive stiffness of chemically end-attached layers of adult and newborn aggrecan was measured in various ionic strength aqueous solutions. Adult aggrecan was significantly weaker in compression than newborn aggrecan even at the same total GAG density and bath ionic strength, suggesting the importance of both electrostatic and non-electrostatic interactions in nanomechanical stiffness. These results provide molecular-level evidence of the effects of age on the conformational and nanomechanical properties of aggrecan, with direct implications for the effects of aggrecan nanostructure on the age-dependence of cartilage tissue biomechanical and osmotic properties.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Structural Biology - Volume 181, Issue 3, March 2013, Pages 264-273
نویسندگان
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