Department of Medicine, Nepean Clinical School, University of Sydney, Penrith, NSW, Australia.
Exp Dermatol. 2010 Aug;19(8):e151-7. doi: 10.1111/j.1600-0625.2009.01029.x.
Extracellular ATP via the activation of purinergic P2 receptors has an emerging role in cutaneous biology; however, the distribution of these receptors in mouse skin is poorly defined. This study investigated whether murine epidermal cell subpopulations express functional purinergic P2X(7) receptors. P2X(7) expression was examined by immunoblotting and immunofluorescence staining of epidermal cells from C57Bl/6 mice. P2X(7) function was evaluated by nucleotide-induced ethidium(+) uptake measurements in epidermal cells from C57Bl/6 mice, and from P2X(7) deficient mice and wild-type littermate controls. P2X(7) was detected in whole epidermal cell preparations, and specifically on Langerhans cells (LCs) and keratinocytes (KCs). ATP induced ethidium(+) uptake into LCs and KCs, with EC(50) values of 503 and 482 microm, respectively. BzATP, and to a lesser extent ATPgammaS and ADP, also induced ethidium(+) uptake; while UTP, alphabeta-meth-ATP and NAD were ineffective. ATP-induced ethidium(+) uptake was impaired by Na(+) and Mg(2+), and the P2X(7) antagonist, A-438079 and was absent in LCs and KCs from P2X(7) deficient mice. These results demonstrate that murine LCs and KCs express functional P2X(7), and support a role for this receptor in cutaneous biology.
细胞外 ATP 通过嘌呤能 P2 受体的激活在皮肤生物学中具有新兴作用；然而，这些受体在小鼠皮肤中的分布尚未明确界定。本研究旨在探讨小鼠表皮细胞亚群是否表达功能性嘌呤能 P2X(7)受体。通过对 C57Bl/6 小鼠表皮细胞的免疫印迹和免疫荧光染色来检测 P2X(7)的表达。通过核苷酸诱导 C57Bl/6 小鼠和 P2X(7)缺陷型小鼠及其野生型同窝对照的表皮细胞中的 ethidium(+)摄取来评估 P2X(7)的功能。P2X(7)在整个表皮细胞制剂中被检测到，并且特别存在于朗格汉斯细胞 (LCs) 和角质形成细胞 (KCs) 上。ATP 诱导 LCs 和 KCs 摄取 ethidium(+)，EC(50)值分别为 503 和 482 μm。BzATP，以及在较小程度上 ATPγS 和 ADP，也诱导 ethidium(+)摄取；而 UTP、alphabeta-meth-ATP 和 NAD 则无效。ATP 诱导的 ethidium(+)摄取被 Na(+)和 Mg(2+) 抑制，并且 P2X(7)拮抗剂 A-438079 以及在 P2X(7)缺陷型小鼠的 LCs 和 KCs 中均不存在。这些结果表明，小鼠 LCs 和 KCs 表达功能性 P2X(7)，并且支持该受体在皮肤生物学中的作用。
