Regulation of interleukin 1 and its receptor in human keratinocytes.
AUTOR(ES)
Blanton, R A
RESUMO
Keratinocytes in culture synthesize and respond to interleukin 1 (IL-1). We have measured surface IL-1 receptor (IL-1R) on keratinocytes in culture using radiolabeled IL-1 binding assays. Surface IL-1R levels are less than 2000 receptors per cell in postconfluent cultures but increase 9- to 20-fold 24 hr after treatment with phorbol 12-myristate 13-acetate (PMA) at 10 ng/ml or after raising the extracellular Ca2+ concentration to 2 mM. This induction of surface IL-1R can be blocked by the addition of retinoic acid and parallels induction of squamous differentiation markers. These results imply that IL-1R levels may be related to the degree of differentiation of these cells. In parallel studies IL-1 protein levels were determined by bioassay and by Western blotting (immunoblots). All detectable IL-1 protein and essentially all IL-1 activity was cell-associated. Although constitutive levels of IL-1 biological activity and protein are significant in these cultures, IL-1 levels increase when either PMA or retinoic acid alone are added to cultures. IL-1 does not increase when PMA and retinoic acid are added simultaneously to cultures; nor is it induced when extracellular Ca2+ concentrations are raised to 2 mM. Thus, cell-associated IL-1 levels do not necessarily parallel surface IL-1R levels in these cultures. Taken together, these results demonstrate that IL-1 and surface IL-1R levels are differentially and complexly regulated in keratinocyte cultures. Possible implications of these results in terms of normal and abnormal regulation of proliferation and differentiation are discussed.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=286670Documentos Relacionados
- 1,25-Dihydroxyvitamin D3 production by human keratinocytes. Kinetics and regulation.
- Human keratinocytes produce but do not process pro-interleukin-1 (IL-1) beta. Different strategies of IL-1 production and processing in monocytes and keratinocytes.
- Interleukin 6 is expressed in high levels in psoriatic skin and stimulates proliferation of cultured human keratinocytes.
- Methotrexate induces differentiation of human keratinocytes.
- Thrombospondin-induced adhesion of human keratinocytes.