Calcium-oxidative stress signaling axis and casein kinase 1α mediate eryptosis and hemolysis elicited by novel p53 agonist inauhzin

Hemocompatibility studies in nanotoxicology: Hemolysis or eryptosis? (A review)

Hemocompatibility evaluation is an important step in nanotoxicological studies. It is generally accepted that nanomaterials promote lysis of erythrocytes, blood clotting, alter phagocytosis, and upregulate pro-inflammatory cytokines. However, there are no standardized guidelines for testing nanomaterials hemocompatibility despite the fact that nanomaterials enter the bloodstream and interact with blood cells. In this review, the current knowledge on the ability of nanomaterials to induce distinct cell death modalities of erythrocytes is highlighted primarily focusing on hemolysis and eryptosis. This review aims to summarize the molecular mechanisms underlying erythrotoxicity of nanomaterials and critically compare the sensitivity and efficiency of hemolysis or eryptosis assays for nanomaterials blood compatibility testing. The list of eryptosis-inducing nanomaterials is growing, but it is still difficult to generalize how physico-chemical properties of nanoparticles affect eryptosis degree and molecular mechanisms involved. Thus, another aim of this review is to raise the awareness of eryptosis as a nanotoxicological tool to encourage the corresponding studies. It is worthwhile to consider adding eryptosis to in vitro nanomaterials hemocompatibility testing protocols and guidelines.

Bufalin reprograms erythrocyte lifespan through p38 MAPK and Rac1 GTPase

Ample evidence indicates that bufalin (BFN), a cardiotonic steroid in Bufo toad toxin, possesses a potent anticancer activity mainly by stimulating apoptosis in cancer cells. Human red blood cells (RBCs) undergo eryptosis which contributes to a plethora of pathological conditions. No reports, however, have examined the potential toxicity of BFN to RBCs. This study aims to characterize the biochemical mechanisms governing the influence of BFN on the physiology and lifespan of RBCs. Isolated RBCs from healthy volunteers were exposed to anticancer concentrations of commercially available BFN from the skin of Bufo gargarizans (10-200 μM) for 24 h at 37 °C. Photometric assays were used to estimate hemolysis and hemolytic markers, and flow cytometry was used to detect eryptotic markers. Phosphatidylserine externalization was captured by fluorescein isothiocyante-labeled annexin V, cellular dimensions by light scatter patterns, and intracellular Ca2+ and reactive oxygen species (ROS) by fluorogenic dyes Fluo4/AM and 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), respectively. BFN caused Ca2+-independent hemolysis and release of LDH, AST, CK, and K+, and increased annexin V-bound cells, cytosolic Ca2+, cell shrinkage, and ROS levels. BFN also disrupted Na+ and Mg2+ trafficking, and was sensitive to PEG 8000, sucrose, SB203580, and NSC 23766. In whole blood, BFN depleted hemoglobin stores, increased fragmented RBCs, and was selectively toxic to reticulocytes, lymphocytes, and platelets. In conclusion, BFN elicits premature RBC death, subject to regulation by p38 MAPK and Rac1 GTPase, and is detrimental to other peripheral blood cells. Altogether, these novel findings prompt cautious consideration of the toxin in anticancer therapy.

Tamoxifen induces eryptosis through calcium accumulation and oxidative stress

Chemotherapy-related anemia is a major obstacle in anticancer therapy. Tamoxifen (TAM) is an antiestrogen prescribed for breast cancer patients with hemolytic potential and apoptotic properties in nucleated cells. However, the eryptotic activity of TAM has hitherto escaped the efforts of investigators. RBCs from apparently healthy volunteers were treated with 1-50 μM of TAM for 24 h at 37 °C. Hemoglobin leakage and LDH, AST, and AChE activities were photometrically determined while K+, Na+, and Mg2+ were detected by ion-selective electrode. Flow cytometry was used to identify eryptotic cells by annexin-V-FITC, intracellular Ca2+ by Fluo4/AM, sell size and morphology by FSC and SSC signals, respectively, and oxidative stress by H2DCFDA. Whole blood was also exposed to 30 μM of TAM for 24 h at 37 °C to examine the toxicity of TAM to WBCs and platelets. TAM caused Ca2+-independent, dose-responsive hemolysis accompanied by K+, LDH, and AST leakage without improving the mechanical stability of RBCs in hypotonic environments. TAM treatment also increased the proportion of cells positive for annexin-V-FITC, Fluo4, and DCF, along with diminished FSC and SSC signals and AChE activity. Notably, TAM toxicity was aggravated by sucrose but abrogated by vitamin C, PEG 8000, and urea. Moreover, TAM exhibited distinct cytotoxic profiles against leukocytes and platelets. TAM-induced eryptosis is characterized by breakdown of membrane asymmetry, inhibition of AChE activity, Ca2+ accumulation, cell shrinkage, and oxidative stress. Vitamin C, PEG 8000, and urea may hold promise to subvert the undesirable toxic effects of TAM on RBCs.

Metabolic exhaustion and casein kinase 1α drive deguelin-induced premature red blood cell death

1. Deguelin (DGN), a retinoid isolated from many plants, exhibits a potent anticancer activity against a wide spectrum of tumour cells. There is a dearth of evidence, however, regarding the toxicity of DGN to red blood cells (RBCs). This is relevant given the prevalent chemotherapy-associated anaemia observed in cancer patients.2. RBCs were exposed to 1-100 μM of DGN for 24 h at 37 °C. Haemolysis and related markers were photometrically measured while flow cytometry was employed to detect phosphatidylserine exposure through Annexin-V-FITC binding and light scatter properties. Additionally, cytosolic Ca2+ and reactive oxygen species were quantified using Fluo4/AM and H2DCFDA, respectively. DGN was also tested against specific signalling inhibitors in addition to vitamin C and ATP.3. DGN caused a significant increase in Annexin-V-positive cells which was accompanied by cell shrinkage without Ca2+ elevation or oxidative stress. DGN also elicited dose-responsive haemolysis which was ameliorated by preventing KCl efflux and in the presence of sucrose, D4476, and ATP. In whole blood, DGN significantly reduced the reticulocyte count and increased platelet distribution width and large cell count.4. DGN triggers premature RBC eryptosis and haemolysis through casein kinase 1α and ATP depletion, and exhibits a specific toxicity towards reticulocytes and platelets.

Casein kinase 1α mediates eryptosis: a review

Eryptosis is a coordinated non-lytic cell death of erythrocytes characterized by cell shrinkage, cell membrane scrambling, Ca²⁺ influx, ceramide accumulation, oxidative stress, activation of calpain and caspases. Physiologically, it aims at removing damaged or aged erythrocytes from circulation. A plethora of diseases are associated with enhanced eryptosis, including metabolic diseases, cardiovascular pathology, renal and hepatic diseases, hematological disorders, systemic autoimmune pathology, and cancer. This makes eryptosis and eryptosis-regulating signaling pathways a target for therapeutic interventions. This review highlights the eryptotic signaling machinery containing several protein kinases and its small molecular inhibitors with a special emphasis on casein kinase 1α (CK1α), a serine/threonine protein kinase with a broad spectrum of activity. In this review article, we provide a critical analysis of the regulatory role of CK1α in eryptosis, highlight triggers of CK1α-mediated suicidal death of red blood cells, cover the knowledge gaps in understanding CK1α-driven eryptosis and discover the opportunity of CK1α-targeted pharmacological modulation of eryptosis. Moreover, we discuss the directions of future research focusing on uncovering crosstalks between CK1α and other eryptosis-regulating kinases and pathways.

Apoptosis-mediated anti-proliferative activity of Calligonum comosum against human breast cancer cells, and molecular docking of its major polyphenolics to Caspase-3

Due to poor diagnosis breast cancer in women has emerged as the most common cause of death disease in developing countries. Medicinal plants have been used for thousands of years and can be useful in healthcare, especially in developing countries. Ethanol extracts of leaves of fire bush or arta (Calligonum comosum; EECC), exhibited significant anticancer potencies against two breast cancer cell lines, MCF-7 and MDA 231. These in vitro effects of EECC indicated potential anticancer activities that were determined to be specific since minimal toxicity was recorded against MCF-12, a non-cancerous breast cell line used as a reference. EECC also induced cell cycle arrest in MCF-7 and MDA 231 as revealed by the increased proportions of sub-G1 cells. Fluorescence-activated cell sorter analysis (FACS), utilizing double staining by annexin V-FITC/propidium iodide, revealed that the observed cytotoxic effects were mediated via apoptosis and necrosis. FACS measurement of thegreater in fluorescence intensity, linked with oxidation of DCFH to DCF, revealed that apoptosis was attributable to production of free radicals. EECC-mediated apoptosis was further validated by observation of up-regulation in the “executioner” enzyme, caspase 3. The current findings reveal that EECC exhibits significant, selective cytotoxicity to breast cancer cells, that proceeds via the generation of ROS, which culminates in apoptosis. The anti-proliferative effects of EECC weres further verified by use of a structure-based, virtual screening between its major bioactive polyphenolic constituents and the apoptosis executioner marker enzyme, caspase-3. Based on their glide score values against the active site of caspase 3, some phyto-constituents present in EECC, such as DL-alpha-tocopherol and campesterol, exhibited distinctive, drug-like potential with no predicted toxicity to non-target cells. Taken together, the usefulness of natural phenolic and flavonoid compounds contained in Calligonum comosum were suggested to be potent anticancer agents.

Eryptosis: Programmed Death of Nucleus-Free, Iron-Filled Blood Cells

Human erythrocytes are organelle-free cells packaged with iron-containing hemoglobin, specializing in the transport of oxygen. With a total number of approximately 25 trillion cells per individual, the erythrocyte is the most abundant cell type not only in blood but in the whole organism. Despite their low complexity and their inability to transcriptionally upregulate antioxidant defense mechanisms, they display a relatively long life time, of 120 days. This ensures the maintenance of tissue homeostasis where the clearance of old or damaged erythrocytes is kept in balance with erythropoiesis. Whereas the regulatory mechanisms of erythropoiesis have been elucidated over decades of intensive research, the understanding of the mechanisms of erythrocyte clearance still requires some refinement. Here, we present the main pathways leading to eryptosis, the programmed death of erythrocytes, with special emphasis on Ca²⁺ influx, the generation of ceramide, oxidative stress, kinase activation, and iron metabolism. We also compare stress-induced erythrocyte death with erythrocyte ageing and clearance, and discuss the similarities between eryptosis and ferroptosis, the iron-dependent regulated death of nucleated blood cells. Finally, we focus on the pathologic consequences of deranged eryptosis, and discuss eryptosis in the context of different infectious diseases, e.g., viral or parasitic infections, and hematologic disorders.

Geraniin inhibits whole blood IFN-γ and IL-6 and promotes IL-1β and IL-8, and stimulates calcium-dependent and sucrose-sensitive erythrocyte death

Correlations between circulating cytokine levels and disease states are well established, and pharmacological modulation of the immune response is thus an important aspect of the assessment of investigational new drugs. Moreover, chemotherapy-related anemia is a major obstacle in cancer treatment. Geraniin (GRN), a tannin extracted from Geranium and other plants, possesses promising antitumor potential. However, the effect of GRN on whole blood (WB) cytokine response and RBC physiology remains unexplored. Heparinized blood from consented, healthy adults was challenged with 100 ng/mL of lipopolysaccharide (LPS) with and without pretreatment with 10 μM of GRN for 24 h at 37 °C, and tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, IL-8, and IL-10 were assayed by ELISA. Moreover, single-cell RBC suspensions were treated with 5-100 μM of GRN for 24 or 48 h at 37 °C and cytotoxicity and canonical eryptotic markers were examined by flow cytometry. It was revealed that GRN significantly attenuated LPS-induced IFN-γ levels, increased IL-1β, decreased IL-6 only in absence of LPS, and aggravated LPS-induced IL-8 while together with LPS significantly diminished IL-10. Furthermore, GRN induced dose-responsive, Ca²⁺-dependent, and sucrose-sensitive hemolysis, along with phosphatidylserine exposure and Ca²⁺ accumulation with no appreciable cell shrinkage or oxidative damage. GRN was also selectively toxic to platelets, significantly delayed reticulocyte maturation, and significantly disrupted leukocyte proportions. In conclusion, GRN regulates the WB cytokine response and promotes premature hemolysis and eryptosis. This study provides insights into the therapeutic utility of GRN in a highly relevant cellular model system.

Lauric Acid, a Dietary Saturated Medium-Chain Fatty Acid, Elicits Calcium-Dependent Eryptosis

Cardiovascular diseases (CVD) are a leading cause of mortality worldwide, and dietary habits represent a major risk factor for dyslipidemia; a hallmark of CVD. Saturated fatty acids contribute to CVD by aggravating dyslipidemia, and, in particular, lauric acid (LA) raises circulating cholesterol levels. The role of red blood cells (RBCs) in CVD is increasingly being appreciated, and eryptosis has recently been identified as a novel mechanism in CVD. However, the effect of LA on RBC physiology has not been thoroughly investigated. RBCs were isolated from heparin-anticoagulated whole blood (WB) and exposed to 50-250 μM of LA for 24 h at 37 °C. Hemoglobin was photometrically examined as an indicator of hemolysis, whereas eryptosis was assessed by Annexin V-FITC for phosphatidylserine (PS) exposure, Fluo4/AM for Ca²⁺, light scatter for cellular morphology, H₂DCFDA for oxidative stress, and BODIPY 581/591 C11 for lipid peroxidation. WB was also examined for RBC, leukocyte, and platelet viability and indices. LA caused dose-responsive hemolysis, and Ca²⁺-dependent PS exposure, elevated erythrocyte sedimentation rate (ESR), cytosolic Ca²⁺ overload, cell shrinkage and granularity, oxidative stress, accumulation of lipid peroxides, and stimulation of casein kinase 1α (CK1α). In WB, LA disrupted leukocyte distribution with elevated neutrophil-lymphocyte ratio (NLR) due to selective toxicity to lymphocytes. In conclusion, this report provides the first evidence of the pro-eryptotic potential of LA and associated mechanisms, which informs dietary interventions aimed at CVD prevention and management.

Antiproliferative Wnt inhibitor wogonin prevents eryptosis following ionophoric challenge, hyperosmotic shock, oxidative stress, and metabolic deprivation

Anemia is a common complication of chemotherapy and may arise due to premature or suicidal death of red blood cells (RBCs). Prevention of RBC death thus lends itself as a promising strategy to counteract anemia. Wogonin (WGN; 5,7-dihydroxy-8-methoxyflavone) is a Wnt inhibitor derived from Scutellaria baicalensis plant with potent cytotoxic and antitumor potential. However, the nature of interaction of WGN with human RBCs is unknown. RBCs from healthy participants were exposed to different hemolytic and eryptotic stimuli for 24 or 48 hr at 37°C in the presence and absence of 100 μM WGN. Calcium overload was induced by 2 μM ionomycin, hyperosmotic shock with excessive sucrose, oxidative stress by 2-phenethyl isothiocyanate (PEITC), and metabolic deprivation by exclusion of glucose. Hemolysis was estimated from extracellular hemoglobin, phosphatidylserine (PS) exposure by Annexin V-FITC, intracellular calcium by Fluo4/AM, and oxidative stress by 2',7'-dichlorodihydrofluorescein diacetate (H₂ DCFDA). While WGN did not rescue the cells from the hemolytic activity of ionomycin, it reduced PS externalization by interfering with calcium influx under both ionomycin treatment and metabolic exhaustion. WGN also significantly inhibited PS exposure upon hyperosmotic shock, but the effect was independent of calcium entry. Moreover, WGN exhibited antihemolytic and anti-eryptotic activities against PEITC without appreciable reduction in ROS levels. Altogether, WGN prevents PEITC-induced hemolysis and suppresses eryptosis due to calcium accumulation, hyperosmotic shock, oxidative stress, and metabolic exhaustion. These novel insights may open new avenues into the therapeutic application of WGN for conditions in which anemia is commonly encountered, most notably cancer. PRACTICAL APPLICATIONS: The herbal supplement Sho-Saiko-To (Xiaochaihu-tang) is commonly prescribed to relieve symptoms of liver disease. Flavonoids from the herbal constituents of Sho-Saiko-To have demonstrated considerable anti-inflammatory, antioxidant, antimicrobial, antitumor, and immunomodulatory properties. In this work, we identify WGN, a major flavonoid in Sho-Saiko-To, as a novel inhibitor of hemolysis and eryptosis of human erythrocytes. Since inordinate erythrocyte death is a major obstacle in therapeutic drug development, our findings argue for the use of WGN as a natural alternative, either as a primary or an adjuvant drug, for a wide assortment of pathological conditions including cancer.

Bioymifi, a novel mimetic of TNF-related apoptosis-induced ligand (TRAIL), stimulates eryptosis

Tumor necrosis factor-related apoptosis-induced ligand (TRAIL) is a cytokine that initiates apoptosis upon binding to death receptor 5 (DR5) on cancer cells. Small molecule TRAIL mimetics have therefore been investigated as promising chemotherapeutic agents. Since anemia of chemotherapy is common, our goal is to investigate the hemolytic and eryptotic properties of novel DR5 agonist bioymifi (BMF) and identify the underlying molecular mechanisms. Whole blood (WB) was stimulated with 100 μM of BMF, whereas red blood cells (RBCs) were treated with 10-100 μM of BMF for 24 h at 37 °C. WB was analyzed for RBC, leukocyte, and platelet indices, while RBCs were examined for hemolysis by light absorbance of free hemoglobin, membrane scrambling by Annexin V-FITC, calcium by Fluo4/AM, cellular morphology by light scatter, and oxidative stress by 2',7'-dichlorodihydrofluorescein diacetate (H₂DCFDA) using flow cytometry. Caspase inhibitor Z-VAD-FMK, p38 inhibitor SB203580, casein kinase 1α inhibitor D4476, receptor-interacting protein 1 inhibitor necrostatin-2, reduced glutathione, or cyclooxygenase (COX) inhibitor aspirin were added accordingly. BMF exerted dose-responsive, calcium-independent hemolysis, reduced RBC hemoglobin, significantly increased Annexin V-, Fluo4-, and DCF-positive cells, along with a dual effect on forward and side light scatter. Notably, the cytotoxic potential of BMF was significantly mitigated upon pharmacological inhibition of p38. Furthermore, BMF exhibited selective toxicity to eosinophils and significantly diminished reticulocyte hemoglobin content. Altogether, these novel findings highlight the adverse outcomes of BMF exposure on RBC physiology and provide the first toxicological assessment of BMF as an antitumor agent.