Necrotic Pathways Research Articles

Possible induction of apoptotic and necrotic death pathways in lung cancer cells by Clinopodium vulgare L. and phenolic acids and flavonoids detection by LC-MS-MS

The objective of this research was to ascertain the phenolic content and antiproliferation and inducing of apoptosis activities of methanol extract of Clinopodium vulgare(CVME) on lung cancer cells.Initially, the viability and proliferation of lung cancer cells treated with CVME were assessed using MTT staining. AnnexinV/Propodium iodide fluorescent staining was then utilized to scan apoptotic cells with a cell counting device. Furthermore, the mRNA levels of proapoptotic Bax and antiapoptotic Bcl-2 were assessed via real-time PCR. Additionally, LC-MS-MS was used to determine the phenolic content of CVME. Following the administration of varying doses of CVME, it was found that the viability and proliferation of lung cancer cells reduced. The Bax and Bcl-2 mRNA levels did not significantly alter, however it was demonstrated that the cells killed by the necrotic pathway rather than by apoptosis. The main components of flavonoids and phenolic acids in CVME were found to be resveratrol and caffeic acid, respectively. Consequently, it can be said that lung cancer cells are inhibited by CVME, an abundant source of phenolics, via the necrotic pathway.

Phenolic Contents, Antioxidant Activities, LCMS Profiles of Mespilus germanica Leaf Extract and Effects on mRNA Transcription Levels of Apoptotic, Autophagic, and Necrotic Genes in MCF7 and A549 Cancer Cell Lines.

Cancer, defined by the continuous, uncontrollable proliferation of cells in the human body, is a disease with a rapidly increasing incidence and mortality rate. Scientists are looking for novel ways to cure and prevent this sneaky disease because of the toxicity of contemporary chemotherapy and the cancer cells' resilience to anticancer drugs. Determining the effect of herbal medicines, which do not have as harmful side effects as synthetic drugs, on cancer cell lines is an essential preliminary study in the production of effective drugs against cancer. In this study, the phenolic acid profile, antioxidant capacity, and cytotoxicity of the medicinal plant Mespilus germanica (MG) leaf extract were determined, and its effects on the expression of some apoptotic, necrotic, and autophagic pathway genes of MCF7 (Human breast cancer line) and A549 (Human lung cancer line) and healthy HDF (Human Dermal Fibroblasts) cells were investigated for the first time. The LCMS device detected many important phenolic compounds previously reported to act against cancer cells in Mespilus germanica leaf extract. DPPH and total phenolic content showed high antioxidant capacity. The cytotoxicity of MG was determined by the MTT method. The levels of mRNA transcription for Atg5, Atg3, Rıpk1, Bcl2, Bax, Apaf1, Caspase-8, Caspase-7, Caspase-3, and Caspase-9, as well as the expression patterns of the DNA damage markers P53 and Parp-1 genes, were assessed. MG leaf extract did not cause significant toxicity against healthy HDF cells. However, it had a cytotoxic effect on A549 and MCF7 cancer cell lines, increasing the transcription levels of essential genes involved in cell death mechanisms. This research is the first to analyze the phenolic components and antioxidant capabilities of leaf extracts from Mespilus germanica. Additionally, it investigates the impact of these extracts on crucial genes involved in cell death pathways of A549 lung cancer, MCF7 breast cancer, and non-cancerous HDF (Human Dermal Fibroblasts) cells.

Synergistic Treatment of Breast Cancer by Combining the Antimicrobial Peptide Piscidin with a Modified Glycolipid.

Piscidin 3 (P3), a peptide produced by fish, and a hexyl ester-modified sophorolipid (SL-HE), have individually shown promise as antimicrobial and anticancer drugs. A recent report by our team revealed that combining P3 with SL-HE in a 1:8 molar ratio resulted in an 8-fold enhancement in peptide activity, while SL-HE improved by 25-fold its antimicrobial activity against the Gram-positive microorganism Bacillus cereus. Extending these findings, the same P3/SL-HE combination was assessed on two breast cancer cell lines: BT-474, a hormonally positive cell line, and MDA-MB-231, an aggressive triple-negative cell line. The results demonstrated that the 1:8 molar ratio of P3/SL-HE synergistically enhances the anticancer effects against both tumorigenic breast cell lines. Mechanistic studies indicate the activation of an intrinsic apoptotic cell death mechanism through an increase in reactive oxygen species and mitochondrial dysfunction and a secondary programmed necrotic pathway that involves pore formation in the plasma membrane. When a fibroblast cell line, CCD1065SK HDF, was utilized to determine selectivity, the synergistic SL-HE/P3 combination exhibited a protective property compared to the use of SL-HE alone and therefore afforded vastly improved selectivity indices. Given the promising results reported herein, the synergistic combination of P3/SL-HE constitutes a novel strategy that merits further study for the treatment of breast cancer.

ZBP1 regulates cytokine production and cell death in lung fibroblasts following influenza virus infection

Abstract Regulated cell death following influenza viral infection is an important determinant of disease severity and is required for effective viral clearance. However, extensive cell death can lead to severe tissue damage and compromised lung function. Z-DNA binding protein-1 (ZBP1) is a critical sensor of influenza A virus (IAV) that can activate both apoptotic (non-inflammatory) or necrotic (inflammatory) cell death pathways. The cell type-specific effects of ZBP1 activation during influenza virus infection have not been clearly defined. Here, our single-cell gene expression studies identified lung fibroblasts as a cell type expressing high levels of Zbp1 following IAV infection in vivo. Following infection in vitro, we observed that ~20% of primary lung fibroblasts were readily infected by IAV but did not support high levels of spreading infection. Lung fibroblasts from wildtype mice underwent cell death with ~50% reduction in cell survival at 24 hours while lung fibroblasts from Zbp1 knockout mice were almost completely resistant to cell death. Analysis of cytokine production prior to cell death demonstrated that IAV infection in lung fibroblasts triggered an early ZBP1-dependent production of inflammatory proteins. Knockout of ZBP1 reduced inflammatory cytokine/chemokine production, but left interferon pathways intact. These studies identify lung fibroblasts as a key cell type activating Zbp1-mediated cytokine production and cell death during influenza virus infection.

Cpd-A1 alleviates acute kidney injury by inhibiting ferroptosis.

Acute kidney injury (AKI) is defined as sudden loss of renal function characterized by increased serum creatinine levels and reduced urinary output with a duration of 7 days. Ferroptosis, an iron-dependent regulated necrotic pathway, has been implicated in the progression of AKI, while ferrostatin-1 (Fer-1), a selective inhibitor of ferroptosis, inhibited renal damage, oxidative stress and tubular cell death in AKI mouse models. However, the clinical translation of Fer-1 is limited due to its lack of efficacy and metabolic instability. In this study we designed and synthesized four Fer-1 analogs (Cpd-A1, Cpd-B1, Cpd-B2, Cpd-B3) with superior plasma stability, and evaluated their therapeutic potential in the treatment of AKI. Compared with Fer-1, all the four analogs displayed a higher distribution in mouse renal tissue in a pharmacokinetic assay and a more effective ferroptosis inhibition in erastin-treated mouse tubular epithelial cells (mTECs) with Cpd-A1 (N-methyl-substituted-tetrazole-Fer-1 analog) being the most efficacious one. In hypoxia/reoxygenation (H/R)- or LPS-treated mTECs, treatment with Cpd-A1 (0.25 μM) effectively attenuated cell damage, reduced inflammatory responses, and inhibited ferroptosis. In ischemia/reperfusion (I/R)- or cecal ligation and puncture (CLP)-induced AKI mouse models, pre-injection of Cpd-A1 (1.25, 2.5, 5 mg·kg-1·d-1, i.p.) dose-dependently improved kidney function, mitigated renal tubular injury, and abrogated inflammation. We conclude that Cpd-A1 may serve as a promising therapeutic agent for the treatment of AKI.

Abstract 5441: Down regulation of cysteine glutamate antiporter in ALDH1A1 expressing oral and breast cancer stem cells induced oxidative stress triggered ferroptosis

Abstract Background: Sulfasalazine, an xCT inhibitor, is being used as a repurposed antineoplastic drug to induce ferroptosis. Ferroptosis is a regulated necrotic cell death pathway that is dependent on iron reserves. Interestingly, cancer stem cells (CSCs) that are regarded as major drivers of resistance to conventional therapies accompanied with tumor relapse and recurrence have bulk amount of iron reserves in the form of ferritin. This suggests that inducing ferroptosis might disrupt stemness and drug resistant mechanisms in cancer stem cells, thereby reducing the risk of drug resistance, cancer recurrence, and relapse. Materials & Methods: In the present study, ALDH1A1 expressing oral (OCSCs) and breast (BCSCs) cancer stem cells were sorted and used to investigate the role of sulfasalazine to induce ferroptosis. To check the self-renewability of CSCs spheroid formation assay was performed and the resultant CSCs were treated with sulfasalazine (SAS) and subjected to gene expression analysis RT PCR and flow cytometry. FACS was performed to check stem cell marker expression, cell cycle arrest, and apoptosis. Results: Our results suggest that the cells showed a gradual increase in sphere formation till S3 in the case of OCSCs and S2 in the case of BCSCs, with a gradual decrease in sphere forming efficiency from the respective generations. When treated with 0.6mM SAS, these cells induced ferroptosis by downregulating stem cell markers like ALDH1A1, SLC7A11, ferritin, and GPx 4 with a concomitant increase in transferrin and STEAP 3. Flow cytometry studies revealed that the cells have undergone mitochondrial dysfunction characterized by loss of membrane potential and the cell cycle progression was halted in the G2/M phase. Conclusion: In the present study, we demonstrate that SAS potentially induced ferroptosis accompanied with oxidative stress in both OCSCs as well as BCSCs by lowering GPx 4 activity, a key enzyme that scavenges the products produced as a result of oxidative stress. Citation Format: Ravishankar Bellala. Down regulation of cysteine glutamate antiporter in ALDH1A1 expressing oral and breast cancer stem cells induced oxidative stress triggered ferroptosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5441.

Lycopene prevents cell death in NRK-52E cells by inhibition of high glucose-activated DNA damage and apoptotic, autophagic, and necrotic pathways.

This study aims to investigate the effects of lycopene on apoptotic, autophagic, and necrotic pathways, oxidative status, and DNA damage in diabetic nephropathy at the molecular level. The sample of the study includes seven groups: lycopene (L), high glucose (G), high glucose + lycopene (GL), and control (C) groups tested at 12 and 24 h. The expression levels of genes in oxidative, apoptotic, autophagic, and necrotic cell death pathways are determined by reverse transcription-quantitative polymerase chain reaction analysis. The comet assay method is used for the analysis of DNA damage. It is observed that adding lycopene to high glucose for protective purposes reduces the expression of genes related to apoptosis, autophagy, and necrosis, as well as the DNA damage index, compared to cells given high glucose alone. Lycopene can be a safe and effective alternative agent.

Down-Regulation of Cysteine-Glutamate Antiporter in ALDH1A1 Expressing Oral and Breast Cancer Stem Cells Induced Oxidative Stress-Triggered Ferroptosis.

Background: Sulfasalazine, an xCT inhibitor, is being used as a repurposed antineoplastic drug to induce ferroptosis. Ferroptosis is a regulated necrotic cell death pathway that is dependent on iron reserves. Interestingly, cancer stem cells (CSCs) that are regarded as major drivers of resistance to conventional therapies accompanied with tumor relapse and recurrence have bulk amount of iron reserves in the form of ferritin. This suggests that inducing ferroptosis might disrupt stemness and drug-resistant mechanisms in cancer stem cells, thereby reducing the risk of drug-resistance, cancer recurrence, and relapse. Materials & Methods: In the present study, ALDH1A1 expressing oral (OCSCs) and breast (BCSCs) cancer stem cells were sorted and used to investigate the role of sulfasalazine to induce ferroptosis. To check the self-renewability of CSCs spheroid formation, assay was performed and the resultant CSCs were treated with sulfasalazine (SAS) and subjected to gene expression analysis RT-PCR and flow cytometry. FACS was performed to check stem cell marker expression, cell cycle arrest, and apoptosis. Results: Our results suggest that the cells showed a gradual increase in sphere formation till S3 in the case of OCSCs and S2 in the case of BCSCs, with a gradual decrease in sphere-forming efficiency from the respective generations. When treated with 0.6mM SAS, these cells induced ferroptosis by downregulating stem cell markers like ALDH1A1, SLC7A11, ferritin, and GPx-4 with a concomitant increase in transferrin and STEAP-3. Flow cytometry studies revealed that the cells have undergone mitochondrial dysfunction characterized by loss of membrane potential and the cell cycle progression was halted in the G2/M phase. Conclusion: In the present study, we demonstrate that SAS potentially induced ferroptosis accompanied with oxidative stress in both OCSCs as well as BCSCs by lowering GPx-4 activity, a key enzyme that scavenges the products produced as a result of oxidative stress.

Ros-responsive dextran-phenylboronic acid-silibinin nanoparticles for targeting delivery of BAPTA-AM to effectively eliminate calcium overload-mediated inflammatory cascades and mitochondrial apoptosis: Alleviating acute liver injury

Calcium overload in hepatocytes mediates the crosstalk and amplification loop with oxidative stress and severe inflammation that initiate pro-apoptotic and necrotic signaling pathways in acute liver injury (ALI). In this study, an N-acetylgalactosamine-modified amphiphilic dextran-silibinin conjugate (GalNAc-Dex-Sil) with ROS-sensitive phenylboronic acid (PBA) linkage was synthesized. The as-prepared amphiphilic polymer was self-assembled into GalNAc-Dex-Sil nanoparticles, which efficiently encapsulated the membrane-permeable calcium chelator BAPTA-AM (BA), achieving GalNAc-mediated hepatocyte-specific targeting and ROS-responsive release in injured hepatocytes through PBA cleavage. Accordingly, a single low-dose injection of formulation (BA: 150 μg·kg−1) significantly alleviated hepatocyte oxidative stress and inflammation, rescued dying hepatocytes, prevented further hepatocyte damage, and ultimately restored liver function in the ALI mouse model by 1) rapidly and effectively eliminating the overloaded calcium and scavenging excessive ROS via released BA to block the feed-forward vicious cycles of the cell damage, 2) inhibiting the inflammatory cascade by decreasing the expression of the key factor of the NF-κB/NLPR3 axis, 3) inhibiting the key branch of the mitochondrial apoptotic pathway (Cyt C/Bcl-2 family/caspase-3 axis) and death receptor pathway (TNFα/Caspase-8 axis), and 4) stabilizing hepatocyte membranes through the synergistic hepatoprotective effect of silibinin. Taken together, this formulation exhibited great potential as a potent and effective ALI treatment strategy.

Synthesis of novel spirochromane incorporating Schiff's bases, potential antiproliferative activity, and dual EGFR/HER2 inhibition: Cell cycle analysis and in silico study

Spirochromanes incorporating Schiff's bases and semicarbazones 4a-e and 5a-j were synthesizedand analyzed for their potential antiproliferative activity using four human cancer cell lines (MCF-7, HCT-116, PC3, and A549). Compounds 5a, 5b and 5g possessed the highest antiproliferative activity among the tested compounds,with an IC50 range of 1.154–9.09 μM. Compound 5j selectively inhibited the PC3 cell proliferation (IC50 = 5.47 μM). Spirochromanes 5a, 5b and 5g exhibited high inhibitory activity against EGFR (IC50 = 0.116, 0.132, and 0.077 μM, respectively) and HER2 (IC50 = 0.055, 0.210 and 0.085 μM, respectively) compared with the references, erlotinib (IC50 = 0.090 and 0.038 μM, respectively) and gefitinib (IC50 = 0.052 and 0.072 μM, respectively). Cell cycle analysis and apoptosis results showed that compounds 5a, 5b and 5g arrested growth inthe S phase, and the programmed cell death induced by these compounds was an apoptotic mechanism rather than a necrotic pathway. Molecular docking studies of spirochromanes 5a, 5b and 5g to EGFR and HER2 binding sites were performed to explore the orientation mode and interaction.

The anti-breast cancer activity of indeno[1,2-b]pyridin-5-one and their hydrazonal precursors endowed with anti-CDK-2 enzyme activity

A new series of aza-indeno[1,2-b]pyridin-5-one derivatives 6a-h was designed. The novel pyridin-5-one derivatives were constructed via cyclization of their corresponding hydrazonal precursors 4a-h with indandione. Structural elucidation of all new compounds was fully conducted. All novel hydrazonals 4a-h and indeno-pyridinone derivatives 6a-h were screened for their anti-breast cancer activity against two cell lines; MCF-7 and MDA-231. Among all screened compounds, hydrazonals 4a and 4h showed the highest cytotoxic potency. The cell cycle analysis data revealed that hydrazonals 4a and 4h caused a 1.36- and 1.2-fold increase in the proportion of cells in S phase. Annexin V-FITC apoptosis test for the same two hydrazonal derivatives 4a and 4h indicated that these molecules induce apoptosis by means of the programmed cell death pathway rather than the necrotic pathway. Pharmacokinetic parameters of these two hydrazonals as well as their molecular docking study with the CDK-2 enzyme, provided more insights of their biological activity and druggability.

Doxorubicin-induced senescence promotes resistance to cell death by modulating genes associated with apoptotic and necrotic pathways in prostate cancer DU145 CD133+/CD44+ cells

Cancer stem cells (CSCs) are the most important cause of cancer treatment failure. Traditional cancer treatments, such as chemotherapy and radiotherapy, damage healthy cells alongside malignant cells, leading to severe adverse effects. Therefore, inducing cellular senescence without triggering apoptosis, which further damages healthy cells, may be an alternative strategy. However, there is insufficient knowledge regarding senescence induction in CSCs that show resistance to treatment and stemness properties. The present study aims to elucidate the effects of senescence induction on proliferation, cell cycle, and apoptosis in prostate CSCs and non-CSCs. Prostate CSCs were isolated from DU145 cancer cells using the FACS method. Subsequently, senescence induction was performed in RWPE-1, DU145, prostate CSCs, and non-CSCs by using different concentrations of Doxorubicin (DOX). Cellular senescence was detected using the senescence markers SA-β-gal, Ki67, and senescence-associated heterochromatin foci (SAHF). The effects of senescence on cell cycle and apoptosis were evaluated using the Muse Cell Analyzer, and genes in signaling pathways associated with the apoptotic/necrotic pathway were analyzed by real-time PCR. Prostate CSCs were isolated with 95.6 ± 1.4% purity according to CD133+/CD44+ characteristics, and spheroid formation belonging to stem cells was observed. After DOX-induced senescence, we observed morphological changes, SA-β-gal positivity, SAHF, and the lack of Ki67 in senescent cells. Furthermore; we detected G2/M cell cycle arrest and downregulation of various apoptosis-related genes in senescent prostate CSCs. Our results showed that DOX is a potent inducer of senescence for prostate CSCs, inhibits proliferation by arresting the cell cycle, and senescent prostate CSCs develop resistance to apoptosis.

Resveratrol in Neurodegeneration, in Neurodegenerative Diseases, and in the Redox Biology of the Mitochondria.

Neurodegeneration is a process leading to the progressive loss of structure and functions of neurons. Many neurodegenerative diseases such as Alzheimer's disease, Parkinson's disease, and Huntington's disease have shown many common points at the subcellular level. Neurons are metabolically active cells and need a high amount of energy. Mitochondria are known as the energy synthesis center for cells, involved in the synthesis of adenosine triphosphate by oxidative phosphorylation. Rather than just being an energy synthesis center, it has critical importance for many cellular functions such as calcium homeostasis, cell proliferation, cell growth, and apoptosis. In the process of mitochondrial dysfunction, cellular functions are disrupted and cells enter the apoptotic or necrotic pathway. Resveratrol (trans-3,5,4-trihydoxystilbene), a plant-derived polyphenol found in the seed of grapes, berries, peanuts, and wine, has many biological effects such as inhibition of lipid peroxidation, scavenging of free radicals, changes in eicosanoid synthesis, inhibition of platelet aggregation, anti-inflammatory and anticancer activity, and regulation of lipid metabolism. Through the reviewed literature, the current study investigated the protective role of resveratrol in neurodegenerative diseases. Studies show that resveratrol moderates mitochondrial function, redox status, and cellular dynamics in both in vivo and in vitro experimental models of neurodegeneration. Resveratrol suppresses reactive oxygen species production by reducing the activity of complex III due to its competition effect with coenzyme Q. In the present work, we discussed the protective effects of resveratrol on neurodegeneration, neurodegenerative diseases, and the redox biology of the mitochondria.

Placental damage comparison between preeclampsia with COVID-19, COVID-19, and preeclampsia: analysis of caspase-3, caspase-1, and tumor necrosis factor-alpha expression

Some studies have reported that preeclampsia with coronavirus disease 2019 (COVID-19) significantly increases the risk of adverse perinatal outcome until near to three-fold over the normal pregnancy. Preeclampsia pathophysiology in theory, increases the perinatal mortality and morbidity starting from placental injury which is also believed to share the common pathway with COVID-19 infection. Major typical placental injuries for these matters could be apoptotic, necrotic, or pyroptotic. This study aimed to compare placental damage between those three conditions above in those three typical injuries. This was an observational analytic study with cross-sectional setting. Seventy-two pregnant women admitted to hospital consecutively with diagnosis of preeclampsia with COVID-19, Preeclampsia only and COVID-19 only. Diagnosis for preeclampsia was following FIGO criteria with at least one of the severe features. COVID-19 eligible for this study was PCR test confirmative with moderate to severe clinical degree. Placenta were taken after the delivery, and parameters were quantified with immunohistochemistry test for caspase-3, caspase-1, and TNF-alpha representing apoptotic, pyroptotic, and necrotic pathway respectively. Pregnancy with double complications, preeclampsia, and COVID-19, significantly has the highest placental damage on apoptotic, pyroptotic, and necrotic pathway shown from the caspase-3, caspase-1, and TNF-alpha expression in placenta (p <0.05). Moderate to severe degree of COVID-19 resulting higher placental damage compared to preeclampsia in all the three forms (p <0.05). Apoptotic process was the most prominent among other pathways. Preeclampsia with COVID-19 infection showed significant placental damage, with major changes related were apoptosis, inflammation, and necrosis. This data support poor perinatal outcome of pregnancy having preeclampsia and COVID-19 at the same time.

Dynamic changes in global methylation and plant cell death mechanism in response to NiO nanoparticles.

This report is a first comprehensive work on the potential of engineered nickel oxide nanoparticles affecting the epigenome and modulating global methylation leading to retention of transgenerational footprints. Nickel oxide nanoparticles (NiO-NPs) are known to instigate extensive phenotypic and physiological damage to plants. In the present work, it was shown that exposure to increasing concentrations of NiO-NP-induced cell death cascades in model systems, Allium cepa and tobacco BY-2 cells. NiO-NP also generated variation in global CpG methylation; its transgenerational transmission was shown in affected cells. Plant tissues exposed to NiO-NP showed progressive replacement of essential cations, like Fe and Mg, as seen in XANES and ICP-OES data, providing earliest signs of disturbed ionic homeostasis. Fluorescent staining based confocal microscopy confirmed upsurge of H2O2 and nitric oxide after NiO-NP exposure. A NiO-NP concentration gradient-based switching-on of the cell death cascades was observed when autophagosomes were seen in samples exposed to lower and median concentrations of NiO-NP (10-125mg L-1). The apoptotic cell death marker, caspase-3 like protein, was noted in the median to higher doses (50-500mg L-1), and leakage of lactate dehydrogenase marking necrotic cell death was observed in samples exposed to the highest doses (125-500mg L-1) of NiO-NP. Concomitant increase of DNA hypermethylation (quantified by ELISA-based assay) and genomic DNA damage (evaluated through Comet-based analyses) was recorded at higher doses of NiO-NP. MSAP profiles confirmed that global methylation changes incurring in the parental generation upon NiO-NP exposure were transmitted through the two subsequent generations of BY-2 cells which was supported by data from A. cepa, too. Thus, it was evident that NiO-NP exposure incited DNA hypermethylation, as an aftermath of oxidative burst, and led to induction of autophagy, apoptotic and necrotic cell death pathways. Global methylation changes induced by NiO-NP exposure can be transmitted through subsequent cell generations.

Necrocide 1 mediates necrotic cell death and immunogenic response in human cancer cells

Many anticancer agents induce apoptosis, mitotic catastrophe or cellular senescence. Here, we report the functional characterization of an experimental inducer of tumor necrosis factor (TNF)-independent necrosis, necrocide-1 (NC1). NC1 (but not its stereoisomer) killed a panel of human cancer cells (but not normal cells) at nanomolar concentrations and with a non-apoptotic, necrotic morphotype, both in vitro and in vivo. NC1-induced killing was not inhibited by caspase blockers, anti-apoptotic BCL2 overexpression or TNFα neutralization, suggesting that NC1 elicits a bona fide necrotic pathway. However, pharmacological or genetic inhibition of necroptosis, pyroptosis and ferroptosis failed to block NC1-mediated cell death. Instead, NC1 elicited reactive oxygen species (ROS) production by mitochondria, and elimination of mitochondrial DNA, quenching of mitochondrial ROS, as well as blockade of mitochondrial permeability transition with cyclosporine A, interfered with NC1-induced cell death. NC1 induced hallmarks of immunogenic cell death incurring calreticulin (CALR) exposure, ATP secretion and high mobility group box 1 (HMGB1) release. Taken together, these data identify a previously uncharacterized signaling cascade leading to an immunogenic variant of mitochondrion-regulated necrosis, supporting the notion that eliciting regulated necrosis may constitute a valid approach for anticancer therapy.

RIPK necrotic cell death pathway in both donor photoreceptor and host immune cells synergize to affect photoreceptor graft survival.

Photoreceptor transplant has been put forward as a repair strategy to tackle degenerated retinas. Nonetheless, cell death and immune rejection seriously limit the success of this strategy, with only a small fraction of transplanted cells surviving. Improving the survival of transplanted cells is of critical importance. Recent evidence has identified receptor-interacting protein kinase 3 (RIPK3) as a molecular trigger controlling necroptotic cell death and inflammation. However, its role in photoreceptor transplantation and regenerative medicine has not been studied. We hypothesized that modulation of RIPK3 to address both cell death and immunity could have advantageous effects on photoreceptor survival. In a model of inherited retinal degeneration, deletion of RIPK3 in donor photoreceptor precursors significantly increases the survival of transplanted cells. Simultaneous RIPK3 deletion in donor photoreceptors and recipients maximizes graft survival. Lastly, to discern the role of RIPK3 in the host immune response, bone marrow transplant experiments demonstrated that peripheral immune cell RIPK3 deficiency is protective for both donor and host photoreceptor survival. Interestingly, this finding is independent of photoreceptor transplantation, as the peripheral protective effect is also observed in an additional retinal detachment photoreceptor degeneration model. Altogether, these results indicate that immunomodulatory and neuroprotective strategies targeting the RIPK3 pathway can aid regenerative therapies of photoreceptor transplantation.

Gene expression profiles for apoptotic and necrotic pathways during Amanita phalloides intoxication in mice

Background and Aims: Amanita phalloides is the deadliest toxic mushroom in the world and causes death from acute liver failure. α-amanitin (α-AMA), the most potent toxin, inhibits RNA polymerase II in hepatocytes, stops protein synthesis, and causes hepatotoxicity. However, the information about the mechanisms underlying hepatotoxicity caused by α-AMA is quite inadequate. This study aims to reveal the complex necrotic and apoptotic mechanisms occurring in mouse hepatocytes depending on A. phalloides exposure time in vivo. Methods: BALB-c male mice were divided into 5 groups (n=7): control, α-AMA-2, α-AMA-12, α-AMA-72, and α-AMA-96 groups. A poisoning model was created by oral administration of A. phalloides mushroom extract containing 10 mg/kg of α-AMA to mice and they were sacrificed after 2, 12, 72, and 96 h. Then, TNF-α, Bax, caspase-3, and Bcl-2 gene expression levels in liver tissues were examined by the RT-qPCR method. Time-dependent damage to liver tissues was also evaluated histopathologically. Results: RT-qPCR results showed that proinflammatory cytokine TNF-α mRNA expression levels increased in mouse liver tissues at 2 and 12 h after A. phalloides administration compared among the groups. Bax mRNA expression levels increased in the 12 and 72 h after A. phalloides ingestion. It was observed that caspase-3 mRNA expression levels increased in the 72 and 96 h groups compared among the groups, while Bcl-2 mRNA expression levels decreased in the 72 and 96 h groups. Conclusion: Our findings showed that necrotic mechanisms develop in the early period after A. phalloides mushroom poisoning, and then apoptotic mechanisms are effective. In conclusion, understanding the mechanisms of A. phalloides-induced hepatotoxicity will provide important information for new treatment strategies to be developed.

Resolution Potential of Necrotic Cell Death Pathways

During tissue damage caused by infection or sterile inflammation, not only damage-associated molecular patterns (DAMPs), but also resolution-associated molecular patterns (RAMPs) can be activated. These dying cell-associated factors stimulate immune cells localized in the tissue environment and induce the production of inflammatory mediators or specialized proresolving mediators (SPMs). Within the current prospect of science, apoptotic cell death is considered the main initiator of resolution. However, more RAMPs are likely to be released during necrotic cell death than during apoptosis, similar to what has been observed for DAMPs. The inflammatory potential of many regulated forms of necrotic cell death modalities, such as pyroptosis, necroptosis, ferroptosis, netosis, and parthanatos, have been widely studied in necroinflammation, but their possible role in resolution is less considered. In this review, we aim to summarize the relationship between necrotic cell death and resolution, as well as present the current available data regarding the involvement of certain forms of regulated necrotic cell death in necroresolution.

Current Insights in the Mechanisms of Cobra Venom Cytotoxins and Their Complexes in Inducing Toxicity: Implications in Antivenom Therapy.

Cytotoxins (CTXs), an essential class of the non-enzymatic three-finger toxin family, are ubiquitously present in cobra venoms. These low-molecular-mass toxins, contributing to about 40 to 60% of the cobra venom proteome, play a significant role in cobra venom-induced toxicity, more prominently in dermonecrosis. Structurally, CTXs contain the conserved three-finger hydrophobic loops; however, they also exhibit a certain degree of structural diversity that dictates their biological activities. In their mechanism, CTXs mediate toxicity by affecting cell membrane structures and membrane-bound proteins and activating apoptotic and necrotic cell death pathways. Notably, some CTXs are also responsible for depolarizing neurons and heart muscle membranes, thereby contributing to the cardiac failure frequently observed in cobra-envenomed victims. Consequently, they are also known as cardiotoxins (CdTx). Studies have shown that cobra venom CTXs form cognate complexes with other components that potentiate the toxic effects of the venom's individual component. This review focuses on the pharmacological mechanism of cobra venom CTXs and their complexes, highlighting their significance in cobra venom-induced pathophysiology and toxicity. Furthermore, the potency of commercial antivenoms in reversing the adverse effects of cobra venom CTXs and their complexes in envenomed victims has also been discussed.