Center for Innovation in Immunoregulative Technology and Therapeutics, Kyoto University, Kyoto, Japan.
J Invest Dermatol. 2011 Aug;131(8):1660-7. doi: 10.1038/jid.2011.123. Epub 2011 May 19.
G-protein coupled receptors (GPCR) exert diverse physiological functions, many of which are exploited therapeutically. The roles of GPCR in keratinocytes in immune response in the skin, however, remain poorly defined. In this study, we focused on Gi-coupled GPCR in keratinocytes and defined their actions in immunoactivation of cultured keratinocytes in vitro and immune reaction in the skin in vivo. We first activated HaCaT cells by tumor necrosis factor (TNF)-α and IFN-γ and examined effects of various ligands for GPCR on production of CCL17 and CCL5. Agonists for Gi-coupled receptors, particularly GW9508 for GPR40, inhibited CCL17 and CCL5 expression in a pertussis toxin-sensitive manner. The inhibitory effect by GW9508 was abrogated by depletion of GPR40 with RNA interference. GW9508 further suppressed expression of IL-11, IL-24, and IL-33 induced in HaCaT cells by TNF-α and IFN-γ. GW9508 also inhibited CCL5 and CXCL10 production by normal human epidermal keratinocytes. Administration of GW9508 topically to the skin in the challenging phase suppressed ear swelling in a repeated hapten application model and contact hypersensitivity with downregulation of CCL5 and CXCL10, respectively. Thus, in the skin, stimulation of Gi-coupled receptors attenuates induction of critical cytokines and chemokines by proinflammatory cytokines in keratinocytes and suppresses allergic inflammation in the skin.
G 蛋白偶联受体（GPCR）发挥多种生理功能，其中许多功能被用于治疗。然而，GPCR 在皮肤角质形成细胞中的免疫反应中的作用仍未得到明确界定。在本研究中，我们专注于角质形成细胞中的 Gi 偶联 GPCR，并定义了它们在体外培养角质形成细胞免疫激活和体内皮肤免疫反应中的作用。我们首先用肿瘤坏死因子（TNF）-α和 IFN-γ激活 HaCaT 细胞，并研究了各种 GPCR 配体对 CCL17 和 CCL5 产生的影响。Gi 偶联受体的激动剂，特别是 GPR40 的 GW9508，以百日咳毒素敏感的方式抑制 CCL17 和 CCL5 的表达。用 RNA 干扰耗尽 GPR40 可消除 GW9508 的抑制作用。GW9508 进一步抑制了 TNF-α和 IFN-γ诱导的 HaCaT 细胞中 IL-11、IL-24 和 IL-33 的表达。GW9508 还抑制了正常人类表皮角质形成细胞中 CCL5 和 CXCL10 的产生。在挑战阶段将 GW9508 局部施用于皮肤可抑制重复变应原应用模型中的耳部肿胀和接触超敏反应，分别下调 CCL5 和 CXCL10。因此，在皮肤中，Gi 偶联受体的刺激可减弱角质形成细胞中促炎细胞因子诱导的关键细胞因子和趋化因子的诱导，并抑制皮肤中的过敏炎症。
