The co-culture of dermal fibroblasts with human epidermal keratinocytes induces increased prostaglandin E-2 production and cyclooxygenase 2 activity in fibroblasts

[摘要] During wound healing, cell-cell interactions between epidermal keratinocytes and dermal fibroblasts contribute to the organization of epidermis, in which prostaglandin E-2 (PGE(2)) is considered to be involved in proliferation and differentiation of keratinocytes. In the current study, we investigated the regulation of PGE(2) biosynthesis in co-culture of human epidermal keratinocytes and human dermal fibroblasts. The production of PGE(2) was synergistically enhanced in the co-culture at cell ratios of keratinocytes to fibroblasts between 1/8 and 4, whereas the production of PGE(2) was negligible in individual monolayer cultures of keratinocytes or fibroblasts. To address the mechanism of PGE(2) production induced by the co-culture of keratinocytes and fibroblasts, we asked whether either cell-derived soluble factor(s) or direct cell-cell contact was required to augment the production of PGE(2). Neither the fibroblast-conditioned medium nor membrane fractions influenced the production of PGE(2) in keratinocytes. Keratinocyte-conditioned medium greatly enhanced the production of PGE(2) in fibroblasts, however, whereas the effect of keratinocyte-membrane fractions was weaker, The main soluble fraction in the keratinocyte-conditioned medium contained a precursor of interleukin-1 alpha (proIL-1 alpha) by western blot analysis, and PGE(2) production was inhibited by anti-IL-1 alpha antibody, but not by anti-IL-1 beta or by anti-tumor necrosis factor-alpha antibody, The enhanced production of PGE(2) in fibroblasts upon culturing with keratinocytes was due to the induction of COX-2 mRNA mediated by proIL-1 alpha released from keratinocytes. These results suggest that cell-cell interactions of keratinocytes and fibroblasts augment the production of PGE(2) by a mechanism in which the activity of COX-2 in fibroblasts is increased by the keratinocyte-derived proIL-1 alpha in a paracrine manner.

[发布日期] 1997-09-01

[关键词] cell-cell interaction;prointerleukin-1 alpha;wound healing