Inhibition of Ca²⁺Entry and Suicidal Erythrocyte Death by Naringin

Abstract

Naringin is a dietary flavonoid from citrus fruits with antioxidant and antiapoptotic activity. Similar to apoptosis of nucleated cells, suicidal death of erythrocytes or eryptosis is paralleled by cell shrinkage and cell membrane scrambling with phosphatidylserine exposure at the erythrocyte surface. Eryptosis is triggered by increased cytosolic Ca²⁺ activity, e.g. following energy depletion or oxidative stress. The present study thus explored whether naringin interferes with eryptosis. To this end, the cytosolic Ca²⁺ concentration was estimated from Fluo3 fluorescence, phosphatidylserine exposure from annexin-V-binding and cell volume from forward scatter in FACS analysis. As a result, energy depletion (48 h glucose removal) and oxidative stress (30 min exposure to 0.3 mM tert-butylhydroperoxide) increased Fluo-3 fluorescence, decreased the erythrocyte forward scatter and enhanced the percentage of annexin-V-binding erythrocytes. Naringin (up to 40 µM) did not significantly modify Fluo-3 fluorescence, erythrocyte forward scatter or annexin-V-binding in the presence of glucose and absence of oxidative stress. Naringin, however, significantly blunted the effect of glucose depletion and oxidative stress on Fluo-3 fluorescence, erythrocyte forward scatter or annexin-V-binding. In conclusion, naringin blunts the increase of cytosolic Ca²⁺ concentration, the shrinkage, the cell membrane scrambling and thus the suicidal death of erythrocytes following energy depletion or oxidative stress.

The Uremic Toxin Acrolein Promotes Suicidal Erythrocyte Death

“…Accelerated suicidal erythrocyte death may contribute to the anemia of several clinical disorders and eryptosis may be triggered by a wide variety of xenobiotics [22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45]. …”

Down-Regulation of Store-Operated Ca2+ Entry and Na+ Ca2+ Exchange in MCF-7 Breast Cancer Cells by Pharmacological JAK3 Inhibition

“…The Ca 2+ oscillations thus contribute to the regulation of diverse cellular functions [17,[35][36][37][38] including entering into the S and the M phase of the cell cycle [39,40] and cell survival [41,42]. Sustained increases of cytosolic Ca 2+ activity are known to trigger apoptosis [36,38,[43][44][45][46][47][48][49][50][51]. Orai and NCX dependent Ca 2+ oscillations are further instrumental in the stimulation of cell migration [52][53][54].…”

Stimulation of Erythrocyte Cell Membrane Scrambling by Gedunin

“…Eryptosis may be stimulated by a wide variety of xenobiotics [15,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66] and excessive eryptosis is further observed in several clinical conditions including diabetes, renal insufficiency, hemolytic uremic syndrome, sepsis, malaria, sickle cell disease, Wilson's disease, iron deficiency, malignancy, phosphate depletion, and metabolic syndrome [15]. …”