Sato T, Kirimura Y, Mori Y
Department of Biochemistry, School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan.
J Invest Dermatol. 1997 Sep;109(3):334-9. doi: 10.1111/1523-1747.ep12335935.
During wound healing, cell-cell interactions between epidermal keratinocytes and dermal fibroblasts contribute to the organization of epidermis, in which prostaglandin E2 (PGE2) is considered to be involved in proliferation and differentiation of keratinocytes. In the current study, we investigated the regulation of PGE2 biosynthesis in co-culture of human epidermal keratinocytes and human dermal fibroblasts. The production of PGE2 was synergistically enhanced in the co-culture at cell ratios of keratinocytes to fibroblasts between 1/8 and 4, whereas the production of PGE2 was negligible in individual monolayer cultures of keratinocytes or fibroblasts. To address the mechanism of PGE2 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 PGE2. Neither the fibroblast-conditioned medium nor membrane fractions influenced the production of PGE2 in keratinocytes. Keratinocyte-conditioned medium greatly enhanced the production of PGE2 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-1alpha) by western blot analysis, and PGE2 production was inhibited by anti-IL-1alpha antibody, but not by anti-IL-1beta or by anti-tumor necrosis factor-alpha antibody. The enhanced production of PGE2 in fibroblasts upon culturing with keratinocytes was due to the induction of COX-2 mRNA mediated by proIL-1alpha released from keratinocytes. These results suggest that cell-cell interactions of keratinocytes and fibroblasts augment the production of PGE2 by a mechanism in which the activity of COX-2 in fibroblasts is increased by the keratinocyte-derived proIL-1alpha in a paracrine manner.
在伤口愈合过程中，表皮角质形成细胞与真皮成纤维细胞之间的细胞间相互作用有助于表皮的组织形成，其中前列腺素E2（PGE2）被认为参与角质形成细胞的增殖和分化。在本研究中，我们调查了人表皮角质形成细胞与人真皮成纤维细胞共培养时PGE2生物合成的调节情况。在角质形成细胞与成纤维细胞的细胞比例为1/8至4的共培养中，PGE2的产生协同增强，而在角质形成细胞或成纤维细胞的单个单层培养中，PGE2的产生可忽略不计。为了探讨角质形成细胞与成纤维细胞共培养诱导PGE2产生的机制，我们研究了增强PGE2产生是否需要细胞来源的可溶性因子或直接的细胞间接触。成纤维细胞条件培养基和膜组分均不影响角质形成细胞中PGE2的产生。然而，角质形成细胞条件培养基能显著增强成纤维细胞中PGE2的产生，而角质形成细胞膜组分的作用较弱。通过蛋白质印迹分析，角质形成细胞条件培养基中的主要可溶性组分含有白细胞介素-1α前体（proIL-1α），抗IL-1α抗体可抑制PGE2的产生，但抗IL-1β抗体或抗肿瘤坏死因子-α抗体则无此作用。与角质形成细胞共培养时，成纤维细胞中PGE2产生的增强是由于角质形成细胞释放的proIL-1α介导的COX-2 mRNA的诱导。这些结果表明，角质形成细胞与成纤维细胞的细胞间相互作用通过一种旁分泌机制增强PGE2的产生，即角质形成细胞来源的proIL-1α增加成纤维细胞中COX-2的活性。
