Increased store-operated and 1-oleoyl-2-acetyl-sn-glycerol-induced calcium influx in monocytes is mediated by transient receptor potential canonical channels in human essential hypertension.

OBJECTIVE

Activation of nonselective cation channels of the transient receptor potential canonical (TRPC) family has been associated with hypertension. Whether store-operated channels, which are activated after depletion of intracellular stores, or second-messenger-operated channels, which are activated by 1-oleoyl-2-acetyl-sn-glycerol, are affected in essential hypertension is presently unknown.

METHODS

Using a polymerase chain reaction, an in-cell western assay and the fluorescent dye technique we studied TRPC3, TRPC5, and TRPC6 expression and store-operated and 1-oleoyl-2-acetyl-sn-glycerol-induced calcium influx into human monocytes in 19 patients with essential hypertension and in 17 age-matched and sex-matched normotensive control individuals.

RESULTS

We observed a significantly increased expression of TRPC3 and TRPC5, but not TRPC6, in essential hypertension. Store-operated calcium influx was significantly elevated in essential hypertension. Store-operated calcium influx was reduced by the inhibitor 2-aminoethoxydiphenylborane, specific TRPC3 and TRPC5 knockdown, but not TRPC6 knockdown using gene silencing by RNA interference. 1-Oleoyl-2-acetyl-sn-glycerol-induced calcium influx and barium influx were also significantly elevated in essential hypertension. The 1-oleoyl-2-acetyl-sn-glycerol-induced cation influx was reduced by TRPC3 and TRPC5 knockdown.

CONCLUSION

We demonstrated an increased TRPC3 and TRPC5 expression and a subsequently increased store-operated calcium influx and increased 1-oleoyl-2-acetyl-sn-glycerol-induced cation influx in monocytes of patients with essential hypertension. This increased activation of monocytes through TRPC channels in patients with essential hypertension may promote vascular disease in these patients.