Human Keratinocytes Synthesize, Secrete, and Deposit Fibronectin in the Pericellular Matrix

• Published in: Journal of investigative dermatology Vol. 82; no. 6; pp. 580 - 586
• Main Authors: Kubo, Miyoko, Norris, David A., Howell, Samuel E., Ryan, Sheli R, Clark, Richard A F
• Format: Journal Article
• Language: English
• Published: Danvers, MA Elsevier Inc 01.06.1984; Nature Publishing
• Subjects: Biological and medical sciences; Enzyme-Linked Immunosorbent Assay; Epidermal Cells; Epidermis - metabolism; Fibronectins - biosynthesis; Fibronectins - metabolism; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Humans; Vertebrates: skin, associated glands, phaneres, light organs, various exocrine glands (salt gland, uropygial gland...), adipose tissue, connective tissue; Human; Epidermis; Keratinocyte; Extracellular matrix; Biosynthesis; Skin; Metabolism; Fibronectin
• ISSN: 0022-202X; 1523-1747
• DOI: 10.1111/1523-1747.ep12261325

Fibronectin production by human keratinocytes cultured in serum-free, low-calcium medium without a fibroblast feeder layer was examined using several techniques. Immunohistochemical examination confirmed that the cultures were not contaminated with fibroblasts or Langerhans cells. By indirect immunofluorescence, fibronectin appeared as intracellular granules within all cells and as short radial fibrils between the cells and the substratum, and in the pericellular matrix. Conditioned media taken from 4-, 6-, 8-, 10-, and 12-day cultures contained fibronectin as measured by enzyme-linked immunosorbent assay in proportion to the cell number in cultures. Synthesis of fibronectin by 7-day keratinocyte cultures was determined by 18-h [35S]methionine metabolic labeling followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis and autoradiography. Fibronectin accounted for 12% of the secreted protein under these culture conditions. Our results indicate that human keratinocytes under conditions that prevent terminal differentiation in vitro can synthesize, secrete, and deposit fibronectin in the extracellular matrix.