title: Abnormal collagen assembly, though normal phenotype, in alginate bead cultures of chick embryo chondrocytes.
abstract: The collagens produced by chick embryo chondrocytes cultured in alginate beads were investigated both biochemically and ultrastructurally. The cartilage phenotype is maintained for at least 14 days, as indicated by the production of the cartilage-specific collagens II, IX, and XI and the absence of collagen I. There were differences in the distributions of collagens among the three different compartments analyzed (cells and their associated matrix, further-removed matrix (released by alginate solubilization), and culture medium), with large amounts of collagen IX (mainly in proteoglycan form) in the culture medium. Inhibition of lysyl oxidase activity by beta-aminopropionitrile led to an overall decrease in collagen production. In contrast to the biochemical observations, collagen ultrastructure in the extracellular matrix of alginate cultures was not in the form of the expected 64-nm banded fibrils, but rather in the form of segment-long-spacing-like crystallites. This abnormal structure is likely to be a result of alginate disrupting normal assembly. We conclude that, in this system, the native fibrillar structure of the collagenous matrix is not essential for the maintenance of the differentiated phenotype of chondrocytes.
authors.affiliation: Department of Biochemistry, University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: K E
authors.initials: KE
authors.lastname: Gregory
authors.forename: M E
authors.initials: ME
authors.lastname: Marsden
authors.forename: J
authors.initials: J
authors.lastname: Anderson-MacKenzie
authors.forename: J B
authors.initials: JB
authors.lastname: Bard
authors.forename: P
authors.initials: P
authors.lastname: Bruckner
authors.forename: J
authors.initials: J
authors.lastname: Farjanel
authors.forename: S P
authors.initials: SP
authors.lastname: Robins
authors.forename: D J
authors.initials: DJ
authors.lastname: Hulmes
mesh_terms: D000464:Alginates; D000629:Aminopropionitrile / Q000494:pharmacology; D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000648:ultrastructure; D018929:Cell Culture Techniques; D002478:Cells, Cultured; D002642:Chick Embryo; D019902:Chondrocytes / Q000378:metabolism* / Q000648:ultrastructure; D019765:Chondroitin ABC Lyase / Q000378:metabolism; D002845:Chromatography; D003094:Collagen / Q000032:analysis / Q000378:metabolism* / Q000648:ultrastructure; D003460:Crystallization; D017077:Culture Media, Conditioned / Q000737:chemistry; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure*; D005470:Fluorometry; D006909:Hydroxyproline / Q000032:analysis; D008854:Microscopy, Electron; D008863:Microspheres; D010434:Pepsin A / Q000378:metabolism; D010641:Phenotype; D011498:Protein Precursors / Q000032:analysis / Q000378:metabolism
chemical_list: D000464:Alginates; D017077:Culture Media, Conditioned; D011498:Protein Precursors; D000629:Aminopropionitrile; D003094:Collagen; D010434:Pepsin A; D019765:Chondroitin ABC Lyase; D006909:Hydroxyproline