Murine epidermal Langerhans cells and keratinocytes express functional P2X7 receptors

Abstract

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 P2X7 receptors. P2X7 expression was examined by immunoblotting and immunofluorescence staining of epidermal cells from C57Bl/6 mice. P2X7 function was evaluated by nucleotide-induced ethidium+ uptake measurements in epidermal cells from C57Bl/6 mice, and from P2X7 deficient mice and wild-type littermate controls. P2X7 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 EC50 values of 503 and 482 μm, respectively. BzATP, and to a lesser extent ATPγS and ADP, also induced ethidium+ uptake; while UTP, αβ-meth-ATP and NAD were ineffective. ATP-induced ethidium+ uptake was impaired by Na+ and Mg2+, and the P2X7 antagonist, A-438079 and was absent in LCs and KCs from P2X7 deficient mice. These results demonstrate that murine LCs and KCs express functional P2X7, and support a role for this receptor in cutaneous biology. © 2010 John Wiley & Sons A/S.