Identification of Functional Platelet-Activating Factor Receptors on Human Keratinocytes
| Autor: | Robert C. Murphy, M. Rola-Pleszczynski, J. G. Morelli, J. C. Huff, Jeffrey B. Travers, E. W. Gelfand |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Keratinocytes
Receptors Cell Surface Human skin Platelet Membrane Glycoproteins Dermatology Biology Immunofluorescence Biochemistry Calcium in biology Receptors G-Protein-Coupled chemistry.chemical_compound medicine Humans Platelet Activating Factor Receptor Molecular Biology Cells Cultured Skin medicine.diagnostic_test Platelet-activating factor Cell Biology Cell biology HaCaT medicine.anatomical_structure chemistry Cell culture Calcium Keratinocyte |
| Zdroj: | Journal of Investigative Dermatology. 105(6):816-823 |
| ISSN: | 0022-202X |
| DOI: | 10.1111/1523-1747.ep12326581 |
| Popis: | Platelet-activating factor (PAF) is a potent inflammatory mediator that has been shown to be produced by human keratinocytes and is thought to play a role in cutaneous inflammation. Immunofluorescence and radioligand binding studies were used to characterize PAF receptors (PAF-R) on human keratinocytes and the human epidermoid cell lines A-431 and HaCaT. Indirect immunofluorescence studies demonstrated anti-PAF-R staining of primary cultures of human keratinocytes, A-431 cells, and HaCaT cells. Primary cultures of human fibroblasts and the melanoma cell line SK-30 failed to show immunostaining above that seen with control antiserum. With indirect immunofluorescence studies of sections of normal human skin, a granular anti-PAF-R staining pattern was noted on the keratinocyte cell membranes. A-431 cells readily metabolized PAF by deacetylation-reacylation at 37 degrees C, but not at 4 degrees C. Binding studies on crude membrane preparations of A-431 cells conducted at 4 degrees C demonstrated specific binding that reached saturation by 120 min. Scatchard analysis of PAF binding data revealed a single class of high-affinity (KD = 6.3 +/- 0.3 nM) PAF binding sites. The immunofluorescence and radioligand binding sites were shown to be functional PAF-Rs, as 10 pM to 1 microM PAF increased intracellular calcium in primary cultures of human keratinocytes, A-431 cells, and HaCaT cells, whereas PAF treatment of primary cultures of human fibroblasts or the melanoma cell line SK-30 did not result in changes in the intracellular calcium concentration. The structurally dissimilar PAF-R antagonists CV-6209, Ro19-3704, and alprazolam all inhibited the PAF-induced calcium changes in A-431 cells. The CV-6209 inhibition was seen at doses that competed with the PAF binding to these cells. These studies provide the first evidence for the presence of a functional PAF-R expressed on human keratinocytes, suggesting that this lipid mediator may play an important role in normal keratinocytes or in inflammatory dermatology. |
| Databáze: | OpenAIRE |
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