Response of stratified cultures of human keratinocytes to disruption of proteoglycan synthesis by p-nitrophenyl-beta-D-xylopyranoside.
Proteoglycans play a role in regulating proliferation and adhesion of cells to each other and to the basal lamina. Synthesis of proteoglycans is disrupted by beta-xylosides, which serve as alternate substrate sites for glycosaminoglycan chain attachment and therefore prevent glycosylation of the core protein. We have investigated the effects of p-nitrophenyl-beta-D-xylopyranoside (PNP-xyloside) on cultured human keratinocytes. Stratified cultures were incubated for 7 days with PNP-xyloside (0.05-2.0 mM). Concentrations as low as 0.05 mM increased the secretion of free chondroitin sulfate by 10-15-fold over untreated cultures. Cell-associated proteoglycan decreased as PNP-xyloside concentration increased. At 2 mM PNP-xyloside, heparan sulfate as well as chondroitin sulfate addition to core proteins was disrupted: the core protein of epican, a heparan sulfate form of CD44 found on keratinocytes, was detected immunologically but lacked heparan sulfate. 2.0 mM PNP-xyloside reduced the number of attached cells by 20-25% after 7 days, but had little effect on morphology or protein synthesis. These results indicate that intact proteoglycans are not critical for maintaining epidermal keratinocyte stratification, cell-cell adhesion, or growth.
Haggerty
J G
JG
Dermatology Service, VA Medical Center, West Haven, Connecticut 06516.
Bretton
R H
RH
Milstone
L M
LM
D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D002809:Chondroitin Sulfates / Q000378:metabolism; D003470:Culture Media; D004848:Epithelium / Q000187:drug effects; D006027:Glycosides / Q000494:pharmacology*; D019812:Heparan Sulfate Proteoglycans; D006497:Heparan Sulfate / Q000096:biosynthesis; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D046911:Macromolecular Substances; D009994:Osmolar Concentration; D011509:Proteoglycans / Q000037:antagonists & inhibitors / Q000096:biosynthesis*; D013431:Sulfates / Q000378:metabolism
D002809:Chondroitin Sulfates; D003470:Culture Media; D006027:Glycosides; D019812:Heparan Sulfate Proteoglycans; D006497:Heparan Sulfate; D046911:Macromolecular Substances; D011509:Proteoglycans; D013431:Sulfates; C008646:4-nitrophenyl beta-D-xyloside