Sensitization of Erythrocytes to Suicidal Erythrocyte Death Following Water Deprivation

Abstract

Background/Aims: Klotho deficiency results in excessive formation of 1,25(OH)₂D₃, accelerated ageing and early death. Moreover, klotho deficiency enhances eryptosis, the suicidal erythrocyte death characterized by phosphatidylserine exposure at the erythrocyte surface. Triggers of eryptosis include increase of cytosolic Ca²⁺-activity ([Ca²⁺]_i), glucose depletion, hyperosmotic shock and oxidative stress. Klotho expression is decreased and 1,25(OH)₂D₃-formation enhanced by dehydration. The present study thus explored whether dehydration influences eryptosis. Methods: Blood was drawn from hydrated or 36h dehydrated mice. Plasma osmolarity was determined by vapour pressure method, plasma 1,25(OH)₂D₃ and aldosterone concentrations using ELISA, and plasma Ca²⁺-concentration utilizing photometry. Erythrocytes were exposed to Ca²⁺-ionophore ionomycin (1 µM, 30 min), energy depletion (12 h glucose removal), hyperosmotic shock (500 mM sucrose added, 2 h) and oxidative stress (100 µM tert-butyl-hydroperoxide, 30 min) and phosphatidylserine exposure at the erythrocyte surface estimated from annexin V binding. Results: Dehydration increased plasma osmolarity and plasma 1,25(OH)₂D₃ and aldosterone concentrations. Dehydration did not significantly modify phosphatidylserine-exposure of freshly drawn erythrocytes but significantly enhanced the increase of phosphatidylserine-exposure under control conditions and following treatment with ionomycin, glucose-deprivation, hyperosmolarity or tert-butyl-hydroperoxide. Conclusions: Dehydration sensitizes the erythrocytes to spontaneous eryptosis and to the triggering of eryptosis by excessive Ca²⁺-entry, energy depletion, hyperosmotic shock and oxidative stress.

Stimulation of Suicidal Erythrocyte Death by Garcinol

“…The concentrations required for the effect are lower than those required to counteract growth of tumor cells [20]. In theory, lower garcinol concentrations may be required for triggering of eryptosis in clinical conditions associated with enhanced eryptosis susceptibility of the erythrocytes, such as dehydration [48], hyperphosphatemia [58] chronic kidney disease (CKD) [40,[61][62][63], hemolytic-uremic syndrome [64], diabetes [65], hepatic failure [66], malignancy [30], sepsis [67], Sickle-cell disease [30], beta-thalassemia [30], Hb-C and G6PD-deficiency [30], as well as Wilsons disease [68]. In those disorders lower garcinol concentrations may be sufficient to trigger eryptosis.…”

Inhibition of Suicidal Erythrocyte Death by Volasertib

“…Signaling mechanisms inhibiting eryptosis include the kinases AMPK [22], cGMP-dependent protein kinase [22], MSK1/2 [29], PAK2 [22] and sorafenib/sunitinib sensitive kinases [22]. Eryptosis is stimulated by a myriad of xenobiotics [22, and enhanced eryptosis is observed in a variety of clinical conditions including iron deficiency [22], dehydration [84], hyperphosphatemia [74], vitamin D excess [38], chronic kidney disease (CKD) [85][86][87][88][89] hemolytic-uremic syndrome [90], diabetes [91], hepatic failure [92,93], malignancy [94,95], arteritis [96], sepsis [97], sickle-cell disease [22], beta-thalassemia [22], Hb-C and G6PD-deficiency [22], Wilsons disease [98], as well as advanced age [99]. Eryptosis further increases following erythrocyte storage for transfusion [100].…”

Stimulation of Suicidal Erythrocyte Death by Naphthazarin

“…Naphthazarin sensitizes breast cancer cells to the pro-apoptotic effect of radiation [6]. Naphthazarin is effective by various cellular mechanisms including oxidative stress [7,8] [13,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] and accelerated eryptosis contributes to the pathophysiology of several clinical conditions, such as iron deficiency, phosphate depletion, malignancy, metabolic syndrome, diabetes, hepatic and renal insufficiency, dehydration, hyperphosphataemia, haemolytic uraemic syndrome, sepsis, malaria, sickle cell disease, thalassaemia and Wilson's disease [13,[34][35][36].The present study explored whether naphthazarin is able to trigger suicidal death of erythrocytes, that is cells devoid of mitochondria and nuclei, key organelles in the execution of apoptosis. To this end, erythrocytes drawn from healthy volunteers were treated with naphthazarin, and phosphatidylserine surface abundance, cell volume, [Ca 2+ ] i , oxidative stress and ceramide abundance were determined.…”

“…Eryptosis could further be triggered by the activation of casein kinase 1a [13], Janus-activated kinase JAK3 [13], protein kinase C [13] or p38 kinase [13], and by inhibition of AMP-activated kinase AMPK [13], cGMP-dependent protein kinase [13], PAK2 kinase [13] or sorafenib/sunitinib-sensitive kinases [13]. Eryptosis may be elicited by a wide variety of chemicals [13,[15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] and accelerated eryptosis contributes to the pathophysiology of several clinical conditions, such as iron deficiency, phosphate depletion, malignancy, metabolic syndrome, diabetes, hepatic and renal insufficiency, dehydration, hyperphosphataemia, haemolytic uraemic syndrome, sepsis, malaria, sickle cell disease, thalassaemia and Wilson's disease [13,[34][35][36].…”