0397 : Delphinidin and calcium signaling in human T lymphocytes: a basis to elucidate pathways leading to proliferation and apoptosis

Abstract

Delphinidin, an anthocyanin present in red wine, has been reported to exert vasculoprotective properties due to its vasodilatory and antioxidant effects at the level of the endothelium. However, the effect of delphinidin on cells involves in inflammation in cardiovascular diseases remains unknown. We have investigated the effect of delphinidin on the proliferation and apoptosis of T lymphocytes with respect to calcium signaling. Human T cells were isolated from blood of healthy patients. Proliferation was assessed using CyQUANT® NF Cell Proliferation Assay Kit and apoptosis by flow cytometry. Calcium signaling was analyzed using Fluo-4 probe and the mechanisms were depicted using appropriate drugs. Delphinidin did not modify basal proliferation but it was able to decrease the phytohemagglutinin (PHA)-induced proliferation. Inhibitors of capacitative entry and estrogen receptor antagonist, fulvestrant, but not the NO-synthase inhibitor prevented the effect of delphinidin. In addition, delphinidin reduced actinomycin D-induced apoptosis via a mechanism sensitive to capacitative entry inhibitors. Interestingly, delphinidin decreased the ability of thapsigargin to increase both calcium release and entry. The effect of delphinidin was sensitive to capacitative entry inhibitors and partially prevented by fulvestrant but not by the NO synthase inhibitor. Immunohistochemistry analysis showed that delphinidin reduced membrane translocation of STIM-1, a principal step in capacitative entry activation through « calcium release activated channels » CRAC. Together, these data suggest that delphinidin attenuates T lymphocyte activation via multiple cellular targets on the regulation of calcium signaling via estrogen antagonist sensitive and insensitive pathways. The consequence of which results in inhibition of both proliferation and apoptosis. These effects concur to the protective effect of delphinidin on processes leading to inflammation associated with T lymphocyte activation.