Effect of the quercetin on the calcium transport through biological membranes

ONTIVEROS M; RINALDI DE; VIGIL M; MARDER M; ESPELT M.V; MANGIALAVORI I; ROSSI, R; ROSSI JP; FERREIRA-GOMEZ MS

Congreso; Fronteras en biociencia; 2018

Recently, there has been increasing interest in the research on flavonoids from plant sources because of their beneficial properties for health. Several studies have attributed them anti-oxidative, anti-inflammatory, anti-mutagenic, and anti-carcinogenic properties coupled with their capacity to modulate key cellular enzyme functions. Flavonoids exert their effect in different ways, in particular,there are flavonoids related with changes of intracellular calcium concentration suggesting that they could affect the calcium transport, including the sarcoplasmic/endoplasmic reticulum Ca2+-ATPase and the plasma membrane Ca2+-ATPase (PMCA). However, the molecular mechanisms underlying this effect is not yet clear.This work seeks to investigate the effect of a flavonoid -quercetin- on PMCA4, aP-type ATPase essential in the control of intracellular Ca2+ in eukaryotic cells. Results show that quercetin inhibits to purified PMCA4with a K0.5= 0.34 ± 0.01 M and that the inhibition is totally dependent of theMg2+ concentration suggesting that the inhibitor is quercetin-Mg2+ complex. To assess whether the effects observed of quercetin on the purified hPMCA4 could occur in a living cell, we studied: (1) the quercetinlocalization in HEK293T cells, and (2) the cytoplasmic Ca2+ dynamic in HEK293T cellsand CaCo2 cells.Results reveal that quercetin is incorporated into the cells and that itsautofluorescence appear in the nucleus and cytoplasm according to concentrations and incubation times.On the other hands, when HEK293T cells that overexpress PMCA4 are treated with quercetin, the cytoplasmic Ca2+ dynamic is affected probably because the PMCA activity is inhibited. Similar results were obtained in preliminary experimentsin Caco-2 cells.Results indicate that PMCA is inhibited by quercetin in conditions which it appear into the cellssuggesting that it is possible a direct interaction between PMCA cytoplasmic domains and quercetin.In conclusion, our findings suggest that PMCA could be involve in the molecular mechanismunderlyingquercetineffect on biological systems.