Evaluation of the expression and function of the P2X7 receptor and ART1 in human regulatory T-cell subsets Article uri icon

abstract

  • Regulatory T cells that express CD39 (CD39%2b Treg) exhibit specific immunomodulatory properties. Ectonucleotidase CD39 hydrolyses ATP and ADP. ATP is a ligand of the P2X7 receptor and induces the shedding of CD62L and apoptosis. However, the role of ATP in CD39%2b Treg cells has not been defined. Furthermore, NAD can activate the P2X7 receptor via ADP-ribosyltransferase (ART) enzymes and cause cell depletion in murine models. We evaluated the expression and function of P2X7 and ART1 in CD39%2b Treg and CD39- Treg cells in the presence or absence of ATP and NAD. We isolated peripheral blood mononuclear cells from healthy subjects and purified CD4%2b T cells, CD4%2b CD25%2b T cells and CD4%2b CD25%2b CD39%2b T cells. P2X7 and ART1 expression was assessed by flow cytometry and real-time PCR. Our results showed low P2X7 expression on CD39%2b Treg cells and higher levels of ART1 expression in CD4%2b CD39%2b T cells than the other subtypes studied. Neither shedding of CD62L nor cell death of CD39%2b Treg or CD39- Treg cells was observed by 1mM ATP or 60. μM NAD. In contrast, P2Xs receptor-dependent proliferation with 300. μM ATP, was inhibited by NAD in the different cell types analysed. The NAD proliferation-inhibition was increased with P2Xs and A2a agonist and was reversed with P2Xs and A2a antagonist, therefore NAD inhibits P2Xs-dependent proliferation and A2a activation. In conclusion, our results suggest that the altered function and expression of P2X7 and ART1 in the human CD39%2b Treg or CD39- Treg cells could participate in the resistance against cell death induced by ATP or NAD. © 2015 Elsevier GmbH.

publication date

  • 2016-01-01