Fig. 6. ATP is elevated early in hypertension and is responsible for CD86 up-regulation through the P2X7 receptor in APCs.

(A) DAMPs including ATP, uric acid, oxLDL, and HMGB-1 were measured in the plasma of normotensive mice, and mice were made hypertensive for 6 days. (B) Blood plasma ATP levels were measured at different time points after hypertension induction. A group of mice were cotreated with Ang II and hydralazine [14d(Hyd)]. n = 5 for normotensive, Ang II-treated, and Ang II and hydralazine cotreated mice; n = 4 for L-NAME-treated mice. (C) Surface CD86 expression on splenic DCs from mice infused with Ang II for 0, 4, 7, or 14 days. (D) Splenic DCs from naïve mice were stimulated with the indicated concentrations of ATP for 12 hours in vitro, and their surface CD86 expression was measured. (E) Splenic DCs were stimulated with medium or 3 μM ATP. Some ATP-treated cells were also incubated with antagonists to P2X7 [A740003 (A74) or BBG], pan-P2Y (suramin), P2Y2 [AR-C 118925XX (AR-C)], or P2Y1 (BPTU). Surface CD86 was measured after 18 hours. (F) Splenic DCs from P2X7-deficient mice were treated with different concentrations of ATP, and surface CD86 was measured. (G) Surface CD86 expression on splenic DCs and peritoneal macrophages was derived from normotensive and hypertensive P2X7-deficient mice.