Adhesion of a chondrocytic cell line (USAC) to fibronectin and its regulation by proteoglycan.
BACKGROUND
Chondrocytes produce various extracellular matrices during chondrogenesis. Fibronectin and proteoglycan are major extracellular matrix proteins in cartilage tissue, but the interactions between them are not clear.


METHODS
Recently, we succeeded in establishing a cell line (USAC) with phenotypes of chondrocytes from a human osteogenic sarcoma of the mandible. Using this cell line, cell adhesion to fibronectin, the effect of proteoglycan on the cell adhesion and expression of integrin alpha5beta1 were investigated.


RESULTS
Cells immediately adhered to fibronectin and then spread. Proteoglycan inhibited cell adhesion to fibronectin dose-dependently, whereas collagen did not. The expression of both mRNAs of alpha5 and beta1 subunits was detected 12 h after treatment with proteoglycan, but the expression of beta1 subunit mRNA had diminished by 24 h after treatment.


CONCLUSIONS
These findings suggest that proteoglycan might modulate signal transduction from fibronectin by decreasing the expression of alpha5beta1 integrin.
Imoto
Emi
E
Second Department of Oral and Maxillofacial Surgery, School of Dentistry, Ota-ku, Tokyo, Japan. imoemi@senzoku.showa-u.ac.jp
Kakuta
Saburo
S
Hori
Mayumi
M
Yagami
Kimitosi
K
Nagumo
Masao
M
D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000199:Actins / Q000032:analysis; D000704:Analysis of Variance; D002448:Cell Adhesion / Q000187:drug effects; D002460:Cell Line; D002465:Cell Movement; D019902:Chondrocytes / Q000187:drug effects / Q000502:physiology*; D020219:Chondrogenesis / Q000502:physiology; D003094:Collagen / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005109:Extracellular Matrix / Q000502:physiology; D005353:Fibronectins / Q000187:drug effects / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D011509:Proteoglycans / Q000008:administration & dosage / Q000494:pharmacology / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis; D017469:Receptors, Fibronectin / Q000032:analysis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013223:Statistics as Topic; D014407:Tumor Cells, Cultured
D000199:Actins; D005353:Fibronectins; D011509:Proteoglycans; D012333:RNA, Messenger; D017469:Receptors, Fibronectin; D003094:Collagen