Different types of cell death and their shift in shaping disease

Enhanced apoptosis and inflammation allied with autophagic and apoptotic Leishmania amastigotes in the seemingly undamaged ear skin of clinically affected dogs with canine visceral Leishmaniasis

Programmed cell death plays a relevant role in the pathogenesis of visceral Leishmaniasis. Apoptosis selects suitable parasites, regulating parasite density, whereas autophagy eliminates pathogens. This study aimed to assess the inflammation and apoptosis in inflammatory cells and presents a unique description of the presence of autophagic and apoptotic Leishmania amastigotes in naturally Leishmania-infected dogs. Fragments from seemingly undamaged ear skin of sixteen Leishmania-infected dogs and seven uninfected dogs were evaluated through histomorphometry, ultrastructural, immunohistochemical and transmission electron microscopy (TEM) analyses. Leishmania amastigotes were present on seemingly undamaged ear skin only in clinically affected dogs. Parasite load, morphometrical parameters of inflammation and apoptotic index of inflammatory cells were higher in clinically affected animals and were related to clinical manifestations. Apoptotic index and morphometric parameters of the inflammatory infiltrate in undamaged ear skin were positively correlated with parasite load. Apoptotic and non-apoptotic Leishmania amastigotes were observed within neutrophils and macrophages. Leishmania amastigotes were positive for Bax, a marker for apoptosis, by immunohistochemistry. Morphological characteristics of apoptosis and autophagy in Leishmania amastigotes were observed only in phagocytes of clinically affected dogs. Positive correlations were found between histomorphometry and clinical manifestations. Our results showed that apoptosis and autophagy in Leishmania amastigotes may be related to both the increase in parasite load and apoptotic index in inflammatory cells, and with the intensity of the inflammatory response in clinically affected dogs. Thus, our study suggests that apoptotic and autophagy Leishmania within phagocytes may have facilitate the survival of the parasite and it appears to play an important role in the process of Leishmania infection.

Integrative assessment of mixture toxicity of household chemicals using the toxic unit approach and mode of action

Household chemicals used daily are often combined, leading to inhalation exposure to mixtures. However, methods for assessing their toxic effects are limited. This study proposes an in vitro assay strategy for evaluating household chemical mixtures using benzalkonium chloride (BKC) and didecyldimethylammonium chloride (DDAC), a common disinfectant. Our approach utilizes the mode of action (MOA) of chemicals by applying toxicity units (TU) to assess the key events related to lung disease, such as reactive oxygen species (ROS) production and cell death. The TU (EC50) values for BKC and DDAC were 3.97 µg/mL and 1.89 µg/mL, respectively, from cytotoxicity results. The TU value of the mixture (5:5 ratio of BKC to DDAC) was calculated as 2.56 µg/mL. Using the OpenMRA platform, the TU values were predicted as 2.37 µg/mL with the concentration addition (CA) model and 11.26 µg/mL with the independent action (IA) model, indicating that the mixture effects were additive and closer to that predicted using the CA model. Both BKC and DDAC induced apoptosis and ROS production in human epithelial cells in a dose-dependent manner, suggesting similar modes of action in promoting cell death. Our results suggested that BKC and DDAC exhibited additive toxicity when combined. Our results demonstrate the utility of the TU-based approach, which combines cytotoxicity, ROS induction, and apoptosis measurements to evaluate mixture toxicity. This approach may be beneficial for assessing early key events relevant to lung diseases and offers a practical strategy for evaluating the inhalation toxicity of household chemical mixtures.

Live and let die: analyzing ultrastructural features in cell death

Cell death is an important process that supports morphogenesis during development and tissue homeostasis during adult life by removing damaged or unwanted cells and its dysregulation is associated with numerous disease states. There are different pathways through which a cell can undergo cell death, each relying on peculiar molecular mechanisms and morpho-ultrastructural features. To date, however, while molecular and genetic approaches have been successfully integrated into the field, cell death studies rarely incorporate ultrastructural data from electron microscopy. This review article reports a gallery of original transmission electron microscopy images to describe the ultrastructural features of cells undergoing different types of cell death programs, including necrosis, apoptosis, autophagy, mitotic catastrophe, ferroptosis, methuosis, and paraptosis. TEM has been an important technology in cell biology for well over 50 years and still continues to offer significant advantages in the area of cell death research. TEM allows detailed characterization of the ultrastructural changes within the cell, such as the alteration of organelles and subcellular structures, the nuclear reorganization, and the loss of membrane integrity that enable a distinction between the different forms of cell death based on morphological criteria. Possible pitfalls are also described.

Hyperoxia induces autophagy in pulmonary epithelial cells: insights from in vivo and in vitro experiments

Patients with hypoxemia require high-concentration oxygen therapy. However, prolonged exposure to oxygen concentrations 21% higher than physiological concentrations (hyperoxia) may cause oxidative cellular damage. Pulmonary alveolar epithelial cells are major targets for hyperoxia-induced oxidative stress. In this study, we evaluated the therapeutic potential of the antioxidant N-acetyl-L-cysteine (NAC) for preventing hyperoxia-induced cell death. In vitro experiments were performed using the human lung cancer cell line A549. In brief, NAC-treated and untreated cells were exposed to various concentrations of oxygen (hyperoxia) for different durations. The results indicated that hyperoxia inhibited proliferation and caused cell cycle arrest in A549 cells. It also induced necrosis and autophagy. Furthermore, hyperoxia increased intracellular reactive oxygen species levels and altered mitochondrial membrane potential. Co-treatment with NAC improved the survival of cells exposed to 95% oxygen for 24 h. Experiments performed using a neonatal rat model of acute lung injury confirmed that hyperoxia induced an autophagic response. This study provides evidence for hyperoxia-induced autophagy both in vitro and in vivo. NAC can protect A549 cells from death induced by short-term hyperoxia. Our findings may inform protective strategies against hyperoxia-induced injury in developing lungs-for example, bronchopulmonary dysplasia in premature infants.

NIR emissive probe for fluorescence turn-on based dead cell sorting and in vivo viscosity mapping in C. elegans

Dead cell sorting is pivotal and plays a very significant role in homeostasis. Apoptosis and ferroptosis are the two major regulatory cell death processes. Apoptosis is a programmed cell death process, while ferroptosis is a regulatory cell death process. Monitoring the dead cells coming out from these processes is extremely important to stop various cellular dysfunctions. Here, we present a single NIR emissive probe that can observe both apoptotic and ferroptosis regulatory cell deaths. We were able to directly visualize the dead cells in both animal and plant cells upon a significant increase in the fluorescence intensity of the probe. During cell death, the increased cytoplasm viscosity restricted the rotor motion and helped in the fluorescence turn-on of the probe. Lysosomal viscosity was found to play a crucial role in the ferroptosis pathway. On the other hand, the probe was not only efficient in mapping the viscosity in various parts of live Caenorhabditis elegans (C. elegans) bodies but also able to differentiate between live and dead animals.

Ferroptosis driven by nanoparticles for tackling glioblastoma

Glioblastoma (GBM) is the most aggressive, malignant, and drug-resistant brain tumor. There are no effective treatment options for GBM, which usually leads to relapses that cause patients to die a few months later. Ferroptosis, a newly discovered mechanism of regulated cell death, has been identified as a tumor suppressor in solid tumors and represents an alternative to apoptosis resistance. This mechanism of cell death is characterized by iron overload, which is responsible for generating reactive oxygen species (ROS) in the cell. Understanding the ferroptosis pathway and its key regulators can be used to develop rational delivery systems that specifically target these regulators in GBM cells and promote cell death. This review conducted a systematic literature search to better understand the potential of ferroptosis as a target for developing nanoparticles to tackle GBM. The mechanisms of action, design parameters, efficacy, and safety concerns of 16 nanoparticles were evaluated, demonstrating the potential of combining ferroptosis inducers with nanocarriers to promote a selective delivery to the tumor microenvironment.

Death by ribosome

Next to their essential role as protein production factories, ribosomes serve as molecular sensors of cell stress. Stalled and collided ribosomes trigger specific stress signaling, including the ribotoxic stress response (RSR). The RSR is initiated by the mitogen-activated protein (MAP)-3 kinase ZAKα in response to a plethora of translational aberrations, leading to activation of the stress-activated MAP kinases p38 and jun N-terminal kinase (JNK). Recent insights have highlighted an important role for the RSR pathway in triggering programmed cell death processes, including apoptosis and pyroptosis, in a broad range of physiologically relevant conditions. In this review, we summarize recent work on known links between programmed and accidental ribosome toxicity, RSR signaling, and cell death.

Regulation of ubiquitination in sepsis: from PAMP versus DAMP to peripheral inflammation and cell death

Sepsis (sepsis) is a systemic inflammatory response triggered by infection, and its pathologic features include overproduction of peripheral inflammatory factors (e.g., IL-1β, IL-6, TNF-α), which ultimately leads to cytokine storm and multiple organ dysfunction syndrome (MODS). Pathogen-associated molecular patterns (PAMP) and damage-associated molecular patterns (DAMP) induce strong immune responses and exacerbate inflammation by activating pattern recognition receptors (PRRs) in the host. Ubiquitination, as a key protein post-translational modification, dynamically regulates the activity of several inflammation-associated proteins (e.g., RIPK1, NLRP3) through the coordinated action of the E1, E2, and E3 enzymes, affects cell death pathways such as necroptosis and pyroptosis, and ultimately regulates the release of peripheral inflammatory factors. Deubiquitinating enzymes (DUBs), on the other hand, influence the intensity of the inflammatory response in sepsis by counter-regulating the ubiquitination process and balancing pro- and anti-inflammatory signals. This review focuses on how PAMP and DAMP activate inflammatory pathways via PRRs, and the central role of ubiquitination and deubiquitination in the development of sepsis, especially the mechanisms in regulating the secretion of peripheral inflammatory factors and cell death. By deeply dissecting the impact of the balance of ubiquitination and deubiquitination on inflammatory regulation, we further envision its potential as a therapeutic target in sepsis.

Immunogenic properties of nickel-doped maghemite nanoparticles and the implication for cancer immunotherapy

Nanoparticles are commonly used in diagnostics and therapy. They are also increasingly being implemented in cancer immunotherapy because of their ability to deliver drugs and modulate the immune system. However, the effect of nanoparticles on immune cells involved in the anti-tumor immune response is not well understood. The study reported here showed that nickel-doped maghemite nanoparticles (FN NP) are differentially cytotoxic to cultured mouse and human cancer cell lines, causing their death without negatively impacting the subsequent anticancer immune response. It also found that FN NP induced cell death in the mouse colorectal cancer cell line CT26 and human prostate cancer cell line PC-3, but not in the human prostate cancer cell line LNCaP. The induced cancer cell death did not affect the phenotype and responsivity of the isolated mouse peritoneal macrophages, or ex vivo-generated mouse bone marrow-derived, or human monocyte-derived dendritic cells. Additionally, the induced cancer cell death did not prevent the ex vivo-generated mouse or human dendritic cells from stimulating lymphocytes and enriching cell cultures with cancer cell-reactive T-cells. In conclusion, this study shows that FN NP could be a valuable platform for targeting cancer cells without causing immunosuppressive effects on the subsequent anticancer immune response.

A new cannabigerol derivative, LE-127/2, induces autophagy mediated cell death in human cutaneous melanoma cells

Despite the targeted- and immunotherapies used in the past decade, survival rate among patients with metastatic melanoma remains low, therefore, melanoma is responsible for the majority of skin cancer-related deaths. The ongoing investigation of natural antitumor agents, the nonpsychoactive cannabinoid, cannabigerol (CBG) found in Cannabis sativa is emerging as a promising candidate. CBG offers a potential therapeutic role in the treatment of melanoma demonstrating cell growth inhibition in some tumors. Its low water solubility and bioavailability hinder the potential effectiveness. To address these challenges, a modified CBG, namely LE-127/2 was synthesized by Mannich-type reaction. The aim was to investigate the effect of this novel compound on cell proliferation as well as the mechanism of cell death with a particular focus on autophagy and apoptosis. Human cutan melanoma cell lines, WM35, A2058 and WM3000 were utilized for the present study. Cell proliferation of the cells after the treatment with LE-127/2, parent CBG or vemurafenib was assessed by Cell Titer Blue Assay. Cells were treated with a 1.25-80 µM of the above-mentioned compounds, and it was found that at 20 μM of all drugs showed a comparable effective inhibition of cell proliferation, however, vemurafenib and CBG proved to be more effective than LE-127/2. In addition, clonogenic cell survival assays were performed to examine the inhibitory effect of LE-127/2 on the colony formation ability of melanoma cell lines. Cells treated with 20 µM of LE-127/2 for 14 days showed about a 50% suppression of clonogenic cell survival. LE-127/2 exerted the most intensive inhibition on A2058 cell colonies. Furthermore, notably, LDH cytotoxicity assay performed on HaCaT cell line, proved LE-127/2 to be cytotoxic only at higher concentration, such as 80 μM, while the parent CBG was cytotoxic at concentration as low as 5 μM, suggesting that the new CBG derivative as a drug candidate may be applied in human pharmacotherapy without causing a substantial damage in intact epidermal cells. Analysis of protein expression revealed the impact of LE-127/2 on the expression of basic proteins (LC-3, Beclin-1 and p62) involved in the process of autophagy in the three different melanoma cell lines studied. Elevated expression of these proteins was detected as a result of LE-127/2 (20 µM) treatment. LE-127/2 also induced the expression of some proteins involved in apoptosis, and it is particularly noteworthy the increased level of cleaved PARP. Based on the results obtained, it can be concluded that LE-127/2 induced autophagy could lead to the inhibition of cell proliferation and death in melanoma cells.

Pathogen-induced apoptosis in echinoderms: A review

Echinoderms possess unique biological traits that make them valuable models in immunology, regeneration, and developmental biology studies. As a class rich in active substances with significant nutritional and medicinal value, echinoderms face threats from marine pathogens, including bacteria, viruses, fungi, protozoa, and parasites, which have caused substantial economic losses in echinoderm aquaculture. Echinoderms counteract pathogen invasion through innate immunity and programmed cell death, in particular, with apoptosis being essential for eliminating infected or damaged cells and maintaining homeostasis in many echinoderm cell types. Despite the importance of this process, there is a lack of comprehensive and updated reviews on this topic. This review underscores that echinoderm apoptotic pathways exhibit a complexity comparable to that of vertebrates, featuring proteins with unique domains that may indicate the presence of novel signaling mechanisms. We synthesize current knowledge on how echinoderms utilize diverse transcriptional and post-transcriptional mechanisms to regulate apoptosis in response to pathogen infections and explore how pathogens have evolved strategies to manipulate echinoderm apoptosis, either by inhibiting it to create survival niches or by inducing excessive apoptosis to weaken the host. By elucidating the primary apoptotic pathways in echinoderms and the host-pathogen interactions that modulate these pathways, this review aims to reveal new mechanisms of apoptosis in animal immune defense and provide insights into the evolutionary arms race between hosts and pathogens.

Navigating the complexities of cell death: Insights into accidental and programmed cell death

Cell death is a critical biological phenomenon that can be categorized into accidental cell death (ACD) and programmed cell death (PCD), each exhibiting distinct signaling, mechanistic and morphological characteristics. This paper provides a comprehensive overview of seven types of ACD, including coagulative, liquefactive, caseous, fat, fibrinoid, gangrenous and secondary necrosis, discussing their pathological implications in conditions such as ischemia and inflammation. Additionally, we review eighteen forms of PCD, encompassing autophagy, apoptosis, necroptosis, pyroptosis, paraptosis, ferroptosis, anoikis, entosis, NETosis, eryptosis, parthanatos, mitoptosis, and newly recognized types such as methuosis, autosis, alkaliptosis, oxeiptosis, cuprotosis and erebosis. The implications of these cell death modalities for cellular processes, development, and disease-particularly in the context of neoplastic and neurodegenerative disorders-are also covered. Furthermore, we explore the crosstalk between various forms of PCD, emphasizing how apoptotic mechanisms can influence pathways like necroptosis and pyroptosis. Understanding this interplay is crucial for elucidating cellular responses to stress, as well as for its potential relevance in clinical applications and therapeutic strategies. Future research should focus on clarifying the molecular mechanisms that govern different forms of PCD and their interactions.

Ferroptosis as a hero against oral cancer

Cancer is an abnormal condition altering the cells to proliferate out of control simultaneously being susceptible to evolution. The lining which is made up of tissues in the lips, upper throat and mouth can undergo mutations, is recognised as mouth cancer or oral cancer. Substantial number of mouth lesions are identified at a point where it is typically not possible to get effective remedial care. Ferroptosis is a cutting-edge instance of cellular destruction which stands out in distinction to other sorts of cell death. It appears to have distinctive cellular, molecular and gene-level attributes and scavenges on deposits of reactive oxygen species triggered via iron-induced lipid peroxidation. It is said to be involved dichotomously in cancer development. Because the ferroptotic tumour cells put out numerous chemicals that alternatively signal for cancer attenuation or growth. There is increasing proof that researchers are now keenly investigating to stimulate ferroptosis through various inducers and pathways in the intent for oral cancer therapeutics, specifically to kill malignant tumours that refuse to respond well to conventional treatments. Also, it has the ability to reverse chemotherapy and radiotherapy resistance in victims maximising the success rate of the treatments. This review centres on the stimulation of ferroptosis as a stand-alone therapy for oral cancer, or in combination with other medicines, agents and pathways.

Insights into medicinal attributes of imidazo[1,2-a]pyridine derivatives as anticancer agents

Cancer ranks among the most life-threatening diseases worldwide and is continuously affecting all age groups. Consequently, many research studies are being carried out to develop new cancer treatments, but many of them experience resistance and cause severe toxicity to the patients. Therefore, there is a continuous need to design novel anticancer agents that are target-based, have a higher potency, and have minimal toxicity. The imidazo[1,2-a]pyridine (IP) pharmacophore has been found to be a prominent moiety in the field of medicinal chemistry due to its vast biological properties. Also, it holds immense potential for combating cancer with minimal side effects, depending on the substitution patterns of the core structure. IPs exhibit significant capability in regulating various cellular pathways, offering possibilities for targeted anticancer effects. The present review summarizes the anticancer profile of numerous IP derivatives synthesized and developed by various researchers from 2016 till now, as inhibitors of phosphoinositide-3-kinase/mammalian target of rapamycin (PI3K/mTOR), protein kinase B/mammalian target of rapamycin (Akt/mTOR), aldehyde dehydrogenase (ALDH), and tubulin polymerization. This review provides a comprehensive analysis of the anticancer activity afforded by the discussed IP compounds, emphasizing the structure-activity-relationships (SARs). The aim is also to underscore the potential therapeutic future of the IP moiety as a potent partial structure for upcoming cancer drug development and to aid researchers in the field of rational drug design.

The role of S-adenosylhomocysteine hydrolase-like 1 in cancer

This integrative review aims to highlight the importance of investigating the functional role of AHCYL1, also known as IRBIT, in cancer cells. It has recently been suggested that AHCYL1 regulates cell survival/death, stemness capacity, and the host adaptive response to the tumor microenvironment. Despite this knowledge, the role of AHCYL1 in cancer is still controversial, probably due to its ability to interact with multiple factors in a tissue-specific manner. Understanding the mechanisms regulating the functional interplay between the tumor and the tumor microenvironment that controls the expression of AHCYL1 could provide a deeper comprehension of the regulation of tumor development. Addressing how AHCYL1 modulates cellular plasticity processes in a tumoral context is potentially relevant to developing translational approaches in cancer biology.

Genotoxic and Anti-Migratory Effects of Camptothecin Combined with Celastrol or Resveratrol in Metastatic and Stem-like Cells of Colon Cancer

Background: Colorectal cancer is one of the leading and most lethal neoplasms. Standard chemotherapy is ineffective, especially in metastatic cancer, and does not target cancer stem cells. A promising approach to improve cancer treatment is the combination therapy of standard cytostatic drugs with natural compounds. Several plant-derived compounds have been proven to possess anticancer properties, including the induction of apoptosis and inhibition of cancer invasion. This study was focused on investigating in vitro the combination of camptothecin (CPT) with celastrol (CEL) or resveratrol (RSV) as a potential strategy to target metastatic (LOVO) and stem-like (LOVO/DX) colon cancer cells. Methods: The genotoxic effects that drive cancer cells into death-inducing pathways and the ability to inhibit the migratory properties of cancer cells were evaluated. The γH2AX+ assay and Fast-Halo Assay (FHA) were used to evaluate genotoxic effects, the annexin-V apoptosis assay to rate the level of apoptosis, and the scratch test to assess antimigratory capacity. Results: The results showed that both combinations CPT-CEL and CPT-RSV improve general genotoxicity of CPT alone on metastatic cells and CSCs. However, the assessment of specific double-stranded breaks (DSBs) indicated a better efficacy of the CPT-CEL combination on LOVO cells and CPT-RSV in LOVO/DX cells. Interestingly, the combinations CPT-CEL and CPT-RSV did not improve the pro-apoptotic effect of CPT alone, with both LOVO and LOVO/DX cells suggesting activation of different cell death mechanisms. Furthermore, it was found that the combinations of CPT-CEL and CPT-RSV improve the inhibitory effect of camptothecin on cell migration. Conclusions: These findings suggest the potential utility of combining camptothecin with celastrol or resveratrol in the treatment of colon cancer, including more aggressive forms of the disease. So far, no studies evaluating the effects of combinations of these compounds have been published in the available medical databases.

The role of immune cell death in spermatogenesis and male fertility

The male reproductive system provides a distinctive shield to the immune system, safeguarding germ cells (GCs) from autoimmune harm. The testis in mammals creates a unique immunological setting due to its exceptional immune privilege and potent local innate immunity. which can result from a number of different circumstances, including disorders of the pituitary gland, GC aplasia, and immunological elements. Apoptosis, or programmed cell death (PCD), is essential for mammalian spermatogenesis to maintain and ensure an appropriate number of GCs that correspond with the supporting capability of the Sertoli cells. Apoptosis is substantial in controlling the number of GCs in the testis throughout spermatogenesis, and any dysregulation of this process has been linked to male infertility. There is a number of evidence about the potential of PCD in designing novel therapeutic approaches in the treatment of infertility. A detailed understanding of PCD and the processes that underlie immunological infertility can contribute to the progress in designing strategies to prevent and treat male infertility. This review will provide a summary of the role of immune cell death in male reproduction and infertility and describe the therapeutic strategies and agents for treatment based on immune cell death.

Saikosaponins Targeting Programmed Cell Death as Anticancer Agents: Mechanisms and Future Perspectives

Saikosaponins (SS), which are major bioactive compounds in Radix Bupleuri, have long been used clinically for multicomponent, multitarget, and multipathway therapeutic strategies. Programmed cell death (PCD) induction is among the multiple mechanisms of SS and mediates the anticancer efficacy of this drug family. Although SS show promise for anticancer therapy, the available data to explain how SS mediate their key anticancer effects through PCD (apoptosis, autophagy, ferroptosis, and pyroptosis) remain limited and piecemeal. This review offers an extensive analysis of the key pathways and mechanisms involved in PCD and explores the importance of SS in cancer. We believe that high-quality clinical trials and a deeper understanding of the pharmacological targets involved in the signalling cascades that govern tumour initiation and progression are needed to facilitate the development of innovative SS-based treatments. Elucidating the specific anticancer pathways activated by SS and further clarifying how comprehensive therapies lead to cross-link among the different types of cell death will inspire the clinical translation of SS as cancer treatments.

Assessment of silver nanoparticles' antitumor effects: Insights into cell number, viability, and morphology of glioblastoma and prostate cancer cells

Silver nanoparticles (AgNPs) hold promise for cancer therapy. This study aimed to evaluate their impact on tumor and non-tumor cell number, viability, and morphology. Antitumor activity was tested on U-87MG (glioblastoma) and DU-145 (prostate cancer) cell lines. Treatment with AgNPs notably reached a reduction of U-87MG and DU-145 cell growth by 89.30% and 79.74%, respectively, resulting in slower growth rates. AgNPs induced DNA damage, evidenced by reduced nuclear area and DNA content via fluorescent image-based analyses. Conversely, HFF-1 non-tumor cells displayed no significant changes post-AgNPs exposure. Viability assays revealed substantial reductions in U-87MG and DU-145 cells (79% and 63% in MTT assays, 30% and 52.2% in high-content analyses), while HFF-1 cells exhibited lower sensitivity. Tumor cells had notably lower IC50 values than non-tumor cells, indicating selective susceptibility. Transmission electron microscopy (TEM) showed morphological changes post-AgNPs administration, including increased vacuoles, myelin figures, membrane ghosts, cellular extravasation, and membrane projections. The findings suggest the potential of AgNPs against glioblastoma and prostate cancer, necessitating further exploration across other cancer cell lines.

Synthesis and biological research of new imidazolone-sulphonamide-pyrimidine hybrids as potential EGFR-TK inhibitors and apoptosis-inducing agents

Development of new effective EGFR-targeted antitumor agents is needed because of their clinical significance. A new series of imidazolone-sulphonamide-pyrimidine hybrids was designed and synthesized as modified analogs of some reported EGFR inhibitors. The cytotoxic activity of all the synthesized hybrids was investigated against the breast MCF-7 cancerous cell line using doxorubicin (Dox) as a positive control. 4-(Furan-2-ylmethylene)imidazolone-sulphonamide-pyrimidine 6b had the best potent activity against MCF-7 cells with IC50 result of 1.05 μM, which was better than Dox (IC50 = 1.91 μM). In addition, mechanistic studies revealed the ability of compounds 5g, 5h and 6b to inhibit EGFR kinase. Cell cycle analysis revealed that compound 6b can halt MCF-7 cells at the G1 phase with a concomitant decrease in cellular percentage at the S and G2/M phases. This compound produced a noticeable rise in the proportion of apoptotic cells with regard to the untreated control. Furthermore, the effects of hybrid 6b on the expression levels of pro-apoptotic Bax and pro-survival Bcl2 were assessed. The results showed that this compound upregulated the level of Bax expression as well as declined the expression value of Bcl-2 with regard to the untreated control.

Involvement of necroptotic cell death in macrophages in progression of bleomycin and LPS-induced acute exacerbation of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is the severe form of interstitial pneumonias. Acute exacerbation (AE) of IPF is characterized by progressive lung fibrosis with the irreversible lung function decline and inflammation, and is often fatal with poor prognosis. However, the physiological and molecular mechanisms in AE of IPF are still not fully understood. In this study, we investigated the mechanism underlying AE of IPF, using bleomycin (BLM) and lipopolysaccharide (LPS) (BLM + LPS)-treated mice. The mice were treated with a single dose of 1.5 mg/kg BLM (on day 0) and/or 0.5 mg/kg LPS (on day 14), and maintained for another 7 days (total 21 days). Administration of BLM + LPS more severely aggravated the respiratory function, fibrosis, and inflammation in the lungs, together with the elevated interleukin-6 level in bronchoalveolar lavage fluid, than the control or BLM alone-treated mice. Moreover, the terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) assay demonstrated that subsequent treatment with LPS elevated cell death in the lungs of BLM-administered mice. Furthermore, the expression levels of mixed lineage kinase domain-like protein (MLKL), a marker of necroptotic cell death, and CD68-positive macrophages were increased, and most of them were co-stained in the lungs of BLM + LPS-treated mice. These results, taken together, indicate that BLM + LPS treatment showed more exacerbated the respiratory function with extensive fibrosis and inflammation than treatment with BLM alone in mice. Fibrosis and inflammation in AE of IPF seen in BLM + LPS-administered mice included an increase in macrophages and their necroptotic cell death.

Hydrogen sulfide regulates macrophage polarization and necroptosis to accelerate diabetic skin wound healing

Hydrogen sulfide (H2S), recognized as the third gasotransmitter, plays a pivotal role in the pathophysiological processes of various diseases. Cystathionine γ-lyase (CSE) is the main enzyme for H2S production in the skin. However, effects and mechanisms of H2S in diabetic skin wound healing remain unclear. Our findings revealed a decrease in plasma H2S content in diabetic patients with skin wounds. CSE knockout (KO) diabetic mice resulted in delayed wound healing, reduced blood perfusion, and CD31 expression around the wounds. It also led to increased infiltration of inflammatory cells and M1-type macrophages, decreased collagen levels, α-smooth muscle actin (α-SMA), and proliferating cell nuclear antigen (PCNA) expression. Additionally, there were enhanced expressions of necroptosis related proteins, including receptor interacting protein kinase 1 (RIPK1), RIPK3 and mixed lineage kinase domain like protein (MLKL). In comparison, sodium hydrosulfide (NaHS), H2S donor, accelerated skin wound healing in leptin receptor deficiency (db/db) mice. This acceleration was accompanied by increased blood perfusion and CD31 expression, reduced infiltration of inflammatory cells and M1-type macrophages, elevated collagen levels, α-SMA, and PCNA expressions, and decreased necroptosis-related protein expressions together with nuclear factor-κB (NF-κB) p65 phosphorylation. In conclusion, H2S regulates macrophage polarization and necroptosis, contributing to the acceleration of diabetic skin wound healing. These findings offer a novel strategy for the treatment of diabetic skin wounds.

Mitochondria-Targeting Type-I Photodrug: Harnessing Caspase-3 Activity for Pyroptotic Oncotherapy

Precise control of cellular signaling events during programmed cell death is crucial yet challenging for cancer therapy. The modulation of signal transduction in cancer cells holds promise but is limited by the lack of efficient, biocompatible, and spatiotemporally controllable approaches. Here we report a photodynamic strategy that modulates both apoptotic and pyroptotic cell death by altering caspase-3 protein activity and the associated signaling crosstalk. This strategy employs a mitochondria-targeting, near-infrared activatable probe (termed M-TOP) that functions via a type-I photochemical mechanism. M-TOP is less dependent on oxygen and more effective in treating drug-resistant cancer cells, even under hypoxic conditions. Our study shows that higher doses of M-TOP induce pyroptotic cell death via the caspase-3/gasdermin-E pathway, whereas lower doses lead to apoptosis. This photodynamic method is effective across diverse gasdermin-E-expressing cancer cells. Moreover, the M-TOP mediated shift from apoptotic to pyroptotic modulation can evoke a controlled inflammatory response, leading to a robust yet balanced immune reaction. This effectively inhibits both distal tumor growth and postsurgical tumor recurrence. This work demonstrates the feasibility of modulating intracellular signaling through the rational design of photodynamic anticancer drugs.

Apoptotic signaling: Beyond cell death

Apoptosis is the best described form of regulated cell death, and was, until relatively recently, considered irreversible once particular biochemical points-of-no-return were activated. In this manuscript, we examine the mechanisms cells use to escape from a self-amplifying death signaling module. We discuss the role of feedback, dynamics, propagation, and noise in apoptotic signaling. We conclude with a revised model for the role of apoptosis in animal development, homeostasis, and disease.

RIPK1 inhibitors: A key to unlocking the potential of necroptosis in drug development

Within the field of medical science, there is a great deal of interest in investigating cell death pathways in the hopes of discovering new drugs. Over the past two decades, pharmacological research has focused on necroptosis, a cell death process that has just been discovered. Receptor-interacting protein kinase 1 (RIPK1), an essential regulator in the cell death receptor signalling pathway, has been shown to be involved in the regulation of important events, including necrosis, inflammation, and apoptosis. Therefore, researching necroptosis inhibitors offers novel ways to treat a variety of disorders that are not well-treated by the therapeutic medications now on the market. The research and medicinal potential of RIPK1 inhibitors, a promising class of drugs, are thoroughly examined in this study. The journey from the discovery of Necrostatin-1 (Nec-1) to the recent advancements in RIPK1 inhibitors is marked by significant progress, highlighting the integration of traditional medicinal chemistry approaches with modern technologies like high-throughput screening and DNA-encoded library technology. This review presents a thorough exploration of the development and therapeutic potential of RIPK1 inhibitors, a promising class of compounds. Simultaneously, this review highlights the complex roles of RIPK1 in various pathological conditions and discusses potential inhibitors discovered through diverse pathways, emphasizing their efficacy against multiple disease models, providing significant guidance for the expansion of knowledge about RIPK1 and its inhibitors to develop more selective, potent, and safe therapeutic agents.

Immunosuppression in Sepsis: Biomarkers and Specialized Pro-Resolving Mediators

Severe infection can lead to sepsis. In sepsis, the host mounts an inappropriately large inflammatory response in an attempt to clear the invading pathogen. This sustained high level of inflammation may cause tissue injury and organ failure. Later in sepsis, a paradoxical immunosuppression occurs, where the host is unable to clear the preexisting infection and is susceptible to secondary infections. A major issue with sepsis treatment is that it is difficult for physicians to ascertain which stage of sepsis the patient is in. Sepsis treatment will depend on the patient's immune status across the spectrum of the disease, and these immune statuses are nearly polar opposites in the early and late stages of sepsis. Furthermore, there is no approved treatment that can resolve inflammation without contributing to immunosuppression within the host. Here, we review the major mechanisms of sepsis-induced immunosuppression and the biomarkers of the immunosuppressive phase of sepsis. We focused on reviewing three main mechanisms of immunosuppression in sepsis. These are lymphocyte apoptosis, monocyte/macrophage exhaustion, and increased migration of myeloid-derived suppressor cells (MDSCs). The biomarkers of septic immunosuppression that we discuss include increased MDSC production/migration and IL-10 levels, decreased lymphocyte counts and HLA-DR expression, and increased GPR18 expression. We also review the literature on the use of specialized pro-resolving mediators (SPMs) in different models of infection and/or sepsis, as these compounds have been reported to resolve inflammation without being immunosuppressive. To obtain the necessary information, we searched the PubMed database using the keywords sepsis, lymphocyte apoptosis, macrophage exhaustion, MDSCs, biomarkers, and SPMs.

Allantoin Derived From Dioscorea opposita Thunb Ameliorates Cyclophosphamide-Induced Premature Ovarian Failure in Female Rats by Attenuating Apoptosis, Autophagy and Pyroptosis

Background and objectives Cyclophosphamide (CP) is widely used as a chemotherapy drug for the treatment of malignant tumors and autoimmune diseases, but it has strong toxic and side effects and can cause permanent damage to the ovaries, which affects women's quality of life. This study aimed to investigate the anti-premature ovarian failure protective effect of allantoin isolated from Dioscorea opposita Thunb. Methods Firstly, 75 mg/kg CP was injected into rats to establish an in vivo model of premature ovarian failure (POF). The POF rats were divided into the normal control group (NC), premature ovarian failure group (POF), and POF group treated with allantoin (ALL I 140 mg/kg and ALL II 70 mg/kg, daily 21 days). It investigated the estrous cycles, hormone levels, apoptosis rate, mitochondrial membrane potential (MMP), reactive oxygen species (ROS), mitophagy, and protein marker (Bax, Bcl2, LC3B, L-1β, caspase-1 and NLRP3). Results The results indicated that allantoin alleviated cyclophosphamide-induced premature ovarian failure in female rats, decreased the anoestrum, increased the level of estradiol (E2), and decreased the levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), decreased apoptosis rate, MMP, mitophagy and ROS in ovarian granulosa cells of POF rats, down-regulated L-1β, caspase-1, LC3B-II/LC3B-I in ovarian tissue, and up-regulated the Bcl2 and NLRP3. Conclusions Our study revealed the ovarian-protective effect of allantoin in CP-induced premature ovarian failure for the first time, the effect was achieved through attenuation of the apoptosis, autophagy, and pyroptosis. The study underlines the potential clinical application of allantoin as a protectant agent for premature ovarian failure.

The Anti-Oxidative, Anti-Inflammatory, Anti-Apoptotic, and Anti-Necroptotic Role of Zinc in COVID-19 and Sepsis

Zinc is a structural component of proteins, functions as a catalytic co-factor in DNA synthesis and transcription of hundreds of enzymes, and has a regulatory role in protein-DNA interactions of zinc-finger proteins. For many years, zinc has been acknowledged for its anti-oxidative and anti-inflammatory functions. Furthermore, zinc is a potent inhibitor of caspases-3, -7, and -8, modulating the caspase-controlled apoptosis and necroptosis. In recent years, the immunomodulatory role of zinc in sepsis and COVID-19 has been investigated. Both sepsis and COVID-19 are related to various regulated cell death (RCD) pathways, including apoptosis and necroptosis. Lack of zinc may have a negative effect on many immune functions, such as oxidative burst, cytokine production, chemotaxis, degranulation, phagocytosis, and RCD. While plasma zinc concentrations decline swiftly during both sepsis and COVID-19, this reduction is primarily attributed to a redistribution process associated with the inflammatory response. In this response, hepatic metallothionein production increases in reaction to cytokine release, which is linked to inflammation, and this protein effectively captures and stores zinc in the liver. Multiple regulatory mechanisms come into play, influencing the uptake of zinc, the binding of zinc to blood albumin and red blood cells, as well as the buffering and modulation of cytosolic zinc levels. Decreased zinc levels are associated with increasing severity of organ dysfunction, prolonged hospital stay and increased mortality in septic and COVID-19 patients. Results of recent studies focusing on these topics are summarized and discussed in this narrative review. Existing evidence currently does not support pharmacological zinc supplementation in patients with sepsis or COVID-19. Complementation and repletion should follow current guidelines for micronutrients in critically ill patients. Further research investigating the pharmacological mechanism of zinc in programmed cell death caused by invasive infections and its therapeutic potential in sepsis and COVID-19 could be worthwhile.

Redox Status of Erythrocytes as an Important Factor in Eryptosis and Erythronecroptosis

Overall, reactive oxygen species (ROS) signalling significantly contributes to initiation and mo-dulation of multiple regulated cell death (RCD) pathways. Lately, more information has become available about RCD modalities of erythrocytes, including the role of ROS. ROS accumulation has therefore been increasingly recognized as a critical factor involved in eryptosis (apoptosis of erythrocytes) and erythro-necroptosis (necroptosis of erythrocytes). Eryptosis is a Ca2+-dependent apoptosis-like RCD of erythrocytes that occurs in response to oxidative stress, hyperosmolarity, ATP depletion, and a wide range of xenobiotics. Moreover, eryptosis seems to be involved in the pathogenesis of multiple human diseases and pathological processes. Several studies have reported that erythrocytes can also undergo necroptosis, a lytic RIPK1/RIPK3/MLKL-mediated RCD. As an example, erythronecroptosis can occur in response to CD59-specific pore-forming toxins. We have systematically summarized available studies regarding the involvement of ROS and oxidative stress in these two distinct RCDs of erythrocytes. We have focused specifically on cellular signalling pathways involved in ROS-mediated cell death decisions in erythrocytes. Furthermore, we have summarized dysregulation of related erythrocytic antioxidant defence systems. The general concept of the ROS role in eryptotic and necroptotic cell death pathways in erythrocytes seems to be established. However, further studies are required to uncover the complex role of ROS in the crosstalk and interplay between the survival and RCDs of erythrocytes.