Trifluoperazine-Induced Suicidal Erythrocyte Death and S-Nitrosylation Inhibition, Reversed by the Nitric Oxide Donor Sodium Nitroprusside

Abstract

Background and Purpose: The high potency antipsychotic drug trifluoperazine (10-[3-(4-methyl-1-piperazinyl)-propyl]-2-(trifluoromethyl)-(10)H-phenothiazine dihydrochloride; TFP) may either counteract or promote suicidal cell death or apoptosis. Similar to apoptosis, erythrocytes may enter eryptosis, characterized by phosphatidylserine exposure at the cell surface and cell shrinkage. Eryptosis can be stimulated by an increase in cytoplasmic Ca²⁺ concentration ([Ca²⁺]_i) and inhibited by nitric oxide (NO). We explored whether TFP treatment of erythrocytes induces phosphatidylserine exposure, cell shrinkage, and calcium influx, whether it impairs S-nitrosylation and whether these effects are inhibited by NO. Methods: Phosphatidylserine exposure at the cell surface was estimated from annexin-V-binding, cell volume from forward scatter, [Ca²⁺]_i from Fluo3-fluorescence, and protein nitrosylation from fluorescence switch of the Bodipy-TMR/Sypro Ruby signal. Results: Exposure of human erythrocytes to TFP significantly enhanced the percentage of annexin-V-binding cells, raised [Ca²⁺]_i, and decreased S-nitrosylation. The effect of TFP on annexin-V-binding was not affected by removal of extracellular Ca²⁺ alone, but was significantly inhibited by pre-treatment with sodium nitroprusside (SNP), an effect significantly augmented by additional removal of extracellular Ca²⁺. A 3 hours treatment with 0.1 µM Ca²⁺ ionophore ionomycin triggered annexin-V-binding and cell shrinkage, effects fully reversed by removal of extracellular Ca²⁺. Conclusions: TFP induces eryptosis and decreases protein S-nitrosylation, effects blunted by nitroprusside. The effect of nitroprusside is attenuated in the presence of extracellular Ca²⁺.

Oxidative stress, eryptosis and anemia: a pivotal mechanistic nexus in systemic diseases

“…Antioxidant therapy in SCD would, thus, have the potential to reduce the strong anemia prevalent in SCD by inhibition of eryptosis. Vitamin C and NAC have already been shown to inhibit eryptosis in vitro . Besides, vitamin C inhibits eryptosis in glucose‐6‐phosphate‐dehydrogenase deficiency .…”

“…has reported a higher glomerular filtration rate, diminished oxidative stress, and a higher weight gain in rats that underwent a 5/6 nephrectomy and were treated with the antioxidant NAC as compared to untreated rats that underwent this procedure. NAC has been shown to be effective against eryptosis in vitro . Increased eryptosis in CKD mediates enhanced adhesion of erythrocytes to the vascular endothelium which, in turn, could impede microcirculation .…”

The specific PKC-α inhibitor chelerythrine blunts costunolide-induced eryptosis

“…Interestingly, inhibition of PKC-α commonly triggers apoptosis in nucleated cells [30,31], while its inhibition protects anucleated human erythrocytes from stress-induced cell death [32,33], the so-called eryptosis [34]. Eryptosis is triggered by a plenty of xenobiotics [35] and inhibited by several other xenobiotics or by endogenous molecules, including nitric oxide [36], GSH [37] and erythropoietin [38,39]. Due to a wide range of biological activities, costunolide has been extensively studied over the past 20 years.…”

Proliferating tumor cells mimick glucose metabolism of mature human erythrocytes

“…b) Mature human erythrocytes possess transcription factors, including all of the members of the redox-sensitive NFκB-signaling pathways [4]. c) Impairment of nitrosylation induces eryptosis (programmed cell death of erythrocytes, similar to apoptosis) [5]. The terminology eryptosis was introduced by Lang et al [6].…”