Aggrecan and link protein affect cell adhesion to culture plates and to type II collagen.
Cartilage is a hypocellular tissue in which a balance of matrix molecules, especially aggrecan and link protein, play a critical role in maintaining structural integrity. To study the role of aggrecan and link protein in mediating cell activities, we have stably expressed them in NIH/3T3 fibroblasts and observed the effect on cell-substratum interactions. Overexpression of either protein destabilized the cell-substratum interaction. However, when both were co-expressed, the interaction between cell and substratum was less impaired. Similar results were obtained on type II collagen-coated plates. The addition of exogenous gene products into fibroblast cell lines and chondrocyte culture had the same effect as expression of the genes. The addition of exogenous hyaluronan to the growth medium or treatment of cells with hyaluronidase also decreased cell adhesion, indicating that hyaluronan also plays a role in the cell-substratum adhesion. The presence of aggrecan seems to increase the amount of link protein on the cell surface. Chondrocytes expressing high concentrations of aggrecan and link protein were maintained within a matrix network and were able to survive in suspended culture. Imbalances in aggrecan or link protein concentrations, or degradation of hyaluronan, disrupted the network and caused the chondrocytes to aggregate or adhere to the plates.
Yang
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BB
Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Science Center, University of Toronto, North York, Ontario, Canada.
Zhang
Y
Y
Cao
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Yang
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BL
D016475:3T3 Cells; D053674:Aggrecans; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology*; D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods; D002645:Chickens; D011508:Chondroitin Sulfate Proteoglycans / Q000502:physiology; D003094:Collagen / Q000502:physiology*; D017931:DNA Primers; D016326:Extracellular Matrix Proteins / Q000502:physiology; D006820:Hyaluronic Acid / Q000502:physiology; D006821:Hyaluronoglucosaminidase / Q000494:pharmacology; D037181:Lectins, C-Type; D051379:Mice; D016133:Polymerase Chain Reaction; D014176:Protein Biosynthesis; D011506:Proteins / Q000502:physiology*; D011509:Proteoglycans / Q000096:biosynthesis / Q000502:physiology*; D011994:Recombinant Proteins / Q000096:biosynthesis; D014162:Transfection; D000099249:Proteoglycan Link Protein
D053674:Aggrecans; D011508:Chondroitin Sulfate Proteoglycans; D003094:Collagen; D017931:DNA Primers; D016326:Extracellular Matrix Proteins; D006820:Hyaluronic Acid; D006821:Hyaluronoglucosaminidase; D037181:Lectins, C-Type; D011506:Proteins; D011509:Proteoglycans; D011994:Recombinant Proteins; D000099249:Proteoglycan Link Protein; C508320:Acan protein, mouse