Chemotherapy drugs induce pyroptosis through caspase-3 cleavage of a gasdermin

Phosphorylation of caspases by a bacterial kinase inhibits host programmed cell death

The intracellular bacterial pathogen Legionella pneumophila utilizes the Dot/Icm system to translocate over 330 effectors into the host cytosol. These virulence factors modify a variety of cell processes, including pathways involved in cell death and survival, to promote bacterial proliferation. Here, we show that the effector LegK3 is a eukaryotic-like Ser/Thr kinase that functions to suppress host apoptosis. Mechanistically, LegK3 directly phosphorylates multiple caspases involved in apoptosis signaling, including Caspase-3, Caspase-7, and Caspase-9. LegK3-induced phosphorylation of these caspases occurs at serine (Ser29 in Caspase-3 and Ser199 in Caspase-7) or threonine (Thr102 in Caspase-9) residues located in the prodomain or interdomain linkers. These modifications interfere with the suitability of the caspases as the substrates of initiator caspases or upstream regulators without impacting their proteolytic activity. Collectively, our study reveals a novel strategy used by L. pneumophila to maintain the integrity of infected cells for its intracellular growth.

Ubiquitin-independent degradation of Bim blocks macrophage pyroptosis in sepsis-related tissue injury

Pyroptosis, a typical inflammatory cell death mode, has been increasingly demonstrated to have therapeutic value in inflammatory diseases such as sepsis. However, the mechanisms and therapeutic targets of sepsis remain elusive. Here, we reported that REGγ inhibition promoted pyroptosis by regulating members of the gasdermin family in macrophages. Mechanistically, REGγ directly degraded Bim, a factor of the Bcl-2 family that can inhibit the cleavage of GSDMD/E, ultimately preventing the occurrence of pyroptosis. Furthermore, cecal ligation and puncture (CLP)-induced sepsis model mice showed downregulation of REGγ at both the RNA and protein levels. Gasdermin-mediated pyroptosis was augmented in REGγ-knockout mice, and these mice exhibited more severe sepsis-related tissue injury. More importantly, we found that REGγ expression was downregulated in clinical sepsis samples, such as those from patients with Pseudomonas aeruginosa (PA) infection. Finally, PA-infected mice showed decreased REGγ levels in the lung. In summary, our study reveals that the REGγ-Bim-GSDMD/E pathway is a novel regulatory mechanism of pyroptosis in sepsis-related tissue injury.

Cisplatin induces acute liver injury by triggering caspase-3/GSDME-mediated cell pyroptosis

BACKGROUND

Cisplatin triggers Gasdermin E (GSDME) cleavage, causing membrane bubble formation, content release, and inflammation. Caspase-3 activation initiates GSDME cleavage, and thus inhibiting this pathway mitigates cisplatin-induced pyroptosis in hepatocytes. This study aimed to delve into how cisplatin induces liver injury via pyroptosis.

METHODS

For animal experiments, C57BL/6J mice were divided into three groups: control, liver injury model group, and Ac-DMLD-CMK (caspase-3 inhibitor) intervention group. The liver histology was evaluated by hematoxylin and eosin staining, immunohistochemistry, immunofluorescence and TUNEL staining. The mRNA and protein levels were detected by real-time polymerase chain reaction (PCR) and Western blot analysis. For in vitro experiments, HL-7702 cells were treated with cisplatin or GSDME siRNA. Cell pyroptosis was determined via cellular morphology, cytotoxicity and viability detection, flow cytometric assay, and Western blot detection for the expression of pyroptosis-related proteins.

RESULTS

Cisplatin-induced distinct liver morphological changes, hepatocellular injury, and inflammation in mice, along with elevated serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels and increased pro-inflammatory cytokine expression. Heightened macrophage infiltration and hepatocellular death indicated cisplatin-induced hepatotoxicity. Cisplatin upregulated GSDME activation, along with Bax-mediated caspase-3 cleavage both in vivo and in vitro, implicating caspase-3/GSDME-dependent pyroptosis in liver injury. Treatment with Ac-DMLD-CMK ameliorated cisplatin-induced liver injury, reducing hepatocellular lesions, serum ALT and AST levels, cytokine expression, macrophage infiltration, and hepatocyte death. Ac-DMLD-CMK also attenuated GSDME-dependent pyroptosis post-cisplatin induction, as evidenced by decreased GSDME expression, Bax upregulation, and cleaved caspase-3 activation. For HL-7702 cells, GSDME siRNA transfection reduced GSDME expression, attenuated typical signs of cisplatin-induced pyroptosis, partially restored cell viability, and significantly inhibited cytotoxicity and a decrease in the proportion of propidium iodide-positive cells, indicating protection against cisplatin-induced hepatocyte pyroptosis.

CONCLUSION

Our study underscores the role of the caspase-3/GSDME signaling pathway in mediating cisplatin-induced hepatotoxicity, particularly in cases of excessive or cumulative cisplatin exposure. These findings suggest that targeting GSDME could represent a promising therapeutic approach to mitigate cisplatin-induced liver damage.

ACSL4-mediated lipid rafts prevent membrane rupture and inhibit immunogenic cell death in melanoma

Chemotherapy including platinum-based drugs are a possible strategy to enhance the immune response in advanced melanoma patients who are resistant to immune checkpoint blockade (ICB) therapy. However, the immune-boosting effects of these drugs are a subject of controversy, and their impact on the tumor microenvironment are poorly understood. In this study, we discovered that lipid peroxidation (LPO) promotes the formation of lipid rafts in the membrane, which mediated by Acyl-CoA Synthetase Long Chain Family Member 4 (ACSL4) impairs the sensitivity of melanoma cells to platinum-based drugs. This reduction primarily occurs through the inhibition of immunogenic ferroptosis and pyroptosis by reducing cell membrane pore formation. By disrupting ACSL4-mediaged lipid rafts via the removal of membrane cholesterol, we promoted immunogenic cell death, transformed the immunosuppressive environment, and improved the antitumor effectiveness of platinum-based drugs and immune response. This disruption also helped reverse the decrease in CD8+ T cells while maintaining their ability to secrete cytokines. Our results reveal that ACSL4-dependent LPO is a key regulator of lipid rafts formation and antitumor immunity, and that disrupting lipid rafts has the potential to enhance platinum-based drug-induced immunogenic ferroptosis and pyroptosis in melanoma. This novel strategy may augment the antitumor immunity of platinum-based therapy and further complement ICB therapy.

Antagonistic nanobodies implicate mechanism of GSDMD pore formation and potential therapeutic application

Inflammasome activation results in the cleavage of gasdermin D (GSDMD) by pro-inflammatory caspases. The N-terminal domains (GSDMDNT) oligomerize and assemble pores penetrating the target membrane. As methods to study pore formation in living cells are insufficient, the order of conformational changes, oligomerization, and membrane insertion remained unclear. We have raised nanobodies (VHHs) against human GSDMD and find that cytosolic expression of VHHGSDMD-1 and VHHGSDMD-2 prevents oligomerization of GSDMDNT and pyroptosis. The nanobody-stabilized GSDMDNT monomers partition into the plasma membrane, suggesting that membrane insertion precedes oligomerization. Inhibition of GSDMD pore formation switches cell death from pyroptosis to apoptosis, likely driven by the enhanced caspase-1 activity required to activate caspase-3. Recombinant antagonistic nanobodies added to the extracellular space prevent pyroptosis and exhibit unexpected therapeutic potential. They may thus be suitable to treat the ever-growing list of diseases caused by activation of (non-) canonical inflammasomes.

High glucose promotes lipopolysaccharide-induced macrophage pyroptosis through GSDME O-GlcNAcylation

AIM

The high glucose (HG) environment in diabetic periodontitis aggravates the damage of periodontal tissue. Pyroptosis has been shown to be positively correlated with the severity of periodontitis, including macrophage pyroptosis. O-GlcNAcylation is a posttranslational modification that is involved in the pathogenesis of periodontitis. However, whether HG regulates macrophage pyroptosis through O-GlcNAcylation remains uncertain. This study aimed to investigate the effect of HG on the O-GlcNAcylation level of a pyroptosis regulator GSDME in macrophages to further probe the mechanisms of diabetic periodontitis.

METHODS

Blood samples were collected from patients with diabetic periodontitis. THP-1 monocytes were induced to differentiate into macrophages by phorbol 12-myristate 13-acetate and then treated with HG to simulate periodontitis in vitro. GSDME expression of blood samples and macrophages was measured by quantitative real-time PCR. Pyroptosis was assessed by propidium iodide staining, measurement of cell viability, cytotoxicity, protein levels of inflammation factors, and pyroptosis-related proteins. O-GlcNAcylation of GSDME was analyzed using co-immunoprecipitation (co-IP), IP, and western blot.

RESULTS

The results showed that GSDME expression was elevated in patients with periodontitis and HG-treated macrophages. HG inhibited cell viability but increased LDH content, levels of IL-1β, IL-18, TNF-α, NLRP3, GSDMD, and Caspase-1, indicating that HG promoted pyroptosis of macrophages, which was reversed by GSDME knockdown. HG treatment increased O-GlcNAcylation in macrophages. Mechanically, GSDME interacted with OGT, and OGT knockdown suppressed O-GlcNAcylation of GSDME at Ser (S)339 site. Knockdown of OGT inhibited pyroptosis in HG-treated macrophages, while GSDME overexpression partially reversed this inhibition.

CONCLUSION

HG treatment enhanced OGT-mediated GSDME O-GlcNAcylation, thereby augmenting pyroptosis in LPS-induced macrophages. These results may provide a novel sight for the treatment of periodontitis.

Characterization of ferroptosis-triggered pyroptotic signaling in heart failure

Pressure overload-induced cardiac hypertrophy is a common cause of heart failure (HF), and emerging evidence suggests that excessive oxidized lipids have a detrimental effect on cardiomyocytes. However, the key regulator of lipid toxicity in cardiomyocytes during this pathological process remains unknown. Here, we used lipidomics profiling and RNA-seq analysis and found that phosphatidylethanolamines (PEs) and Acsl4 expression are significantly increased in mice with transverse aortic constriction (TAC)-induced HF compared to sham-operated mice. In addition, we found that overexpressing Acsl4 in cardiomyocytes exacerbates pressure overload‒induced cardiac dysfunction via ferroptosis. Notably, both pharmacological inhibition and genetic deletion of Acsl4 significantly reduced left ventricular chamber size and improved cardiac function in mice with TAC-induced HF. Moreover, silencing Acsl4 expression in cultured neonatal rat ventricular myocytes was sufficient to inhibit hypertrophic stimulus‒induced cell growth. Mechanistically, we found that Acsl4-dependent ferroptosis activates the pyroptotic signaling pathway, which leads to increased production of the proinflammatory cytokine IL-1β, and neutralizing IL-1β improved cardiac function in Acsl4 transgenic mice following TAC. These results indicate that ACSL4 plays an essential role in the heart during pressure overload‒induced cardiac remodeling via ferroptosis-induced pyroptotic signaling. Together, these findings provide compelling evidence that targeting the ACSL4-ferroptosis-pyroptotic signaling cascade may provide a promising therapeutic strategy for preventing heart failure.

Starvation-induced phosphorylation activates gasdermin A to initiate pyroptosis

Pyroptosis, a pro-inflammatory form of programmed cell death, is crucial for host defense against pathogens and danger signals. Proteolytic cleavage of gasdermin proteins B-E (GSDMB-GSDME) is well established as a trigger for pyroptosis, but the intracellular activation mechanism of GSDMA remains elusive. Here, we demonstrate that severe starvation induces pyroptosis through phosphorylation-induced activation of GSDMA. Nutrient stresses stimulate GSDMA activation via phosphorylation mediated by Unc-51-like autophagy-activating kinase 1 (ULK1). Phosphorylation of Ser353 on human GSDMA by ULK1 or the phospho-mimetic Ser353Asp mutant of GSDMA liberates GSDMA from auto-inhibition, facilitating its membrane targeting and initiation of pyroptosis. To further validate the significance of GSDMA phosphorylation, we generated a constitutively active mutant Ser354Asp of mouse Gsdma, which induced skin inflammation and hyperplasia in mice, reminiscent of phenotypes with activated Gsdma. This study uncovers phosphorylation of GSDMA as a mechanism underlying pyroptosis initiation and cellular response to nutrient stress.

Pyroptosis and chemical classification of pyroptotic agents

Pyroptosis, as a lytic-inflammatory type of programmed cell death, has garnered considerable attention due to its role in cancer chemotherapy and many inflammatory diseases. This review will discuss the biochemical classification of pyroptotic inducers according to their chemical structure, pyroptotic mechanism, and cancer type of these targets. A structure-activity relationship study on pyroptotic inducers is revealed based on the surveyed pyroptotic inducer chemotherapeutics. The shared features in the chemical structures of current pyroptotic inducer agents were displayed, including an essential cyclic head, a vital linker, and a hydrophilic tail that is significant for π-π interactions and hydrogen bonding. The presented structural features will open the way to design new hybridized classes or scaffolds as potent pyroptotic inducers in the future, which may represent a solution to the apoptotic-resistance dilemma along with synergistic chemotherapeutic advantage.

Trapped in Cells: A Selective Accumulation Approach for Type-I Photodynamic Ablation of Cancer Stem-like Cells

Aldehyde dehydrogenase (ALDH) is an enzyme responsible for converting aldehyde functional groups into carboxylate metabolites. Elevated ALDH activity is a characteristic feature of cancer stem-like cells (CSCs). As a novel approach to target the CSC trait of overexpressing ALDH, we aimed to utilize ALDH activity for the selective accumulation of a photosensitizer in ALDHHigh CSCs. A novel ALDH substrate photosensitizer, SCHO, with thionylated coumarin and N-ethyl-4-(aminomethyl)benzaldehyde was developed to achieve this goal. Our study demonstrated the efficient metabolism of the aldehyde unit of SCHO into carboxylate, leading to its accumulation in ALDHHigh MDA-MB-231 cells. Importantly, we established the selectivity of SCHO as an ALDHHigh cell photosensitizer as it is not a substrate for ABC transporters. SCHO-based photodynamic therapy triggers apoptosis and pyroptosis in MDA-MB-231 cells and further reduces the characteristics of CSCs. Our study presents a novel strategy to target CSCs by exploiting their cellular metabolism to enhance photosensitizer accumulation, highlighting the potential of photodynamic therapy as a powerful tool for eliminating ALDHHigh CSCs.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

Gene Expression Regulation and the Signal Transduction of Programmed Cell Death

Cell death is of great significance in maintaining tissue homeostasis and bodily functions. With considerable research coming to the fore, it has been found that programmed cell death presents in multiple modalities in the body, which is not only limited to apoptosis, but also can be divided into autophagy, pyroptosis, ferroptosis, mitotic catastrophe, entosis, netosis, and other ways. Different forms of programmed cell death have disparate or analogous characteristics with each other, and their occurrence is accompanied by multiple signal transduction and the role of a myriad of regulatory factors. In recent years, scholars across the world have carried out considerable in-depth research on programmed cell death, and new forms of cell death are being discovered continually. Concomitantly, the mechanisms of intricate signaling pathways and regulators have been discovered. More critically, cancer cells tend to choose distinct ways to evade cell death, and different tumors adapt to different manners of death. Therefore, targeting the cell death network has been regarded as an effective tumor treatment strategy for a long time. The objective of our paper is to review the signaling pathways and gene regulation in several typical types of programmed cell death and their correlation with cancer.

Significance of Programmed Cell Death Pathways in Neurodegenerative Diseases

Programmed cell death (PCD) is a form of cell death distinct from accidental cell death (ACD) and is also referred to as regulated cell death (RCD). Typically, PCD signaling events are precisely regulated by various biomolecules in both spatial and temporal contexts to promote neuronal development, establish neural architecture, and shape the central nervous system (CNS), although the role of PCD extends beyond the CNS. Abnormalities in PCD signaling cascades contribute to the irreversible loss of neuronal cells and function, leading to the onset and progression of neurodegenerative diseases. In this review, we summarize the molecular processes and features of different modalities of PCD, including apoptosis, necroptosis, pyroptosis, ferroptosis, cuproptosis, and other novel forms of PCD, and their effects on the pathogenesis of neurodegenerative diseases, such as Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), multiple sclerosis (MS), traumatic brain injury (TBI), and stroke. Additionally, we examine the key factors involved in these PCD signaling pathways and discuss the potential for their development as therapeutic targets and strategies. Therefore, therapeutic strategies targeting the inhibition or facilitation of PCD signaling pathways offer a promising approach for clinical applications in treating neurodegenerative diseases.

Circular RNAs in programmed cell death: Regulation mechanisms and potential clinical applications in cancer: A review

Circular RNAs (circRNAs) are a novel class of non-coding RNAs with covalently closed structures formed by reverse splicing of precursor mRNAs. The widespread expression of circRNAs across species has been revealed by high-throughput sequencing and bioinformatics approaches, indicating their unique properties and diverse functions including acting as microRNA sponges and interacting with RNA-binding proteins. Programmed cell death (PCD), encompassing various forms such as apoptosis, necroptosis, pyroptosis, autophagy, and ferroptosis, is an essential process for maintaining normal development and homeostasis in the human body by eliminating damaged, infected, and aging cells. Many studies have demonstrated that circRNAs play crucial roles in tumourigenesis and development by regulating PCD in tumor cells, showing that circRNAs have the potential to be biomarkers and therapeutic targets in cancer. This review aims to comprehensively summarize the intricate associations between circRNAs and diverse PCD pathways in tumor cells, which play crucial roles in cancer development. Additionally, this review provides a detailed overview of the underlying mechanisms by which circRNAs modulate various forms of PCD for the first time. The ultimate objective is to offer valuable insights into the potential clinical significance of developing novel strategies based on circRNAs and PCD for cancer diagnosis, prognosis, and treatment.

Mitochondria-Targeting AIEgens as Pyroptosis Inducers for Boosting Type-I Photodynamic Therapy of Tongue Squamous Cell Carcinoma

The development of a photosensitizer (PS) that induces pyroptosis could be a star for photodynamic therapy (PDT), particularly with type-I PSs that produce reactive oxygen species (ROS) in a hypoxic tumor microenvironment. Since pyroptosis is a recently characterized cell death pathway, it holds promise for advancing PDT in oncology, with PSs playing a critical role. Herein, we develop a PS named Th-M with aggregation-induced emission (AIE) characteristics for type-I PDT against tongue squamous cell carcinoma (TSCC). Th-M stands out for its exceptional mitochondrial-targeting ability, which triggers mitochondrial dysfunction and leads to Caspase-3 and Gasdermin E (GSDME) cleavage under white light irradiation, inducing pyroptosis in TSCC cells. Our studies verify the effectiveness of Th-M in destroying cancer cells in vitro and suppressing tumor growth in vivo while also demonstrating a favorable biosafety profile. This work pioneers the application of Th-M as a mitochondria-targeted, type-I PS that leverages the mechanism of pyroptosis, offering a potent approach for the treatment of TSSC with promising implications for future PDT of cancers.

Golgi apparatus regulated pyroptosis through the miR-32-5p/Golga7/NLRP3 axis in chicken splenic lymphocytes exposure to ammonia

Ammonia, a common toxic gas, posed a hazard to both human and chickens. The Golgi apparatus, an essential organelle, helped maintain the internal environment of the organism and supported the protein foundation for the endoplasmic reticulum to be involved in pyroptosis. Thus, the Golgi apparatus has garnered significant attention. The purpose of our research was to explore the mechanisms of Golgin A7 (Golga7) involved in pyroptosis after chicken exposure to ammonia. To reach our goal, we first created an in vitro ammonia model to study the effect of ammonia on chicken splenic lymphocyte pyroptosis. Then, leveraging this model, we established Golga7 and miR-32-5p knockdown and overexpression models to investigate their roles in ammonia-induced pyroptosis. We found the ultrastructural changes in the nucleus, Golgi apparatus, and mitochondria of chicken splenic lymphocytes exposure to ammonia. The damage of mitochondria increased the level of Reactive Oxygen Species (ROS), which caused the down-regulation of miR-32-5p. The miR-32-5p inhibitor increased the expression of Golga7 and pyroptosis-related genes (NOD-like receptor protein 3 (NLRP3), Cysteine aspartase-1 (Caspase-1), Golgin A3 (Golga3), Nuclear Factor-kappa B (NF-κB), and Tumor Necrosis Factor-alpha (TNF-α)), which induced the pyroptosis, but when miR-32-5p mimic/si-Golga7 (Golga7 inhibitor) was utilized, these effects were reduced. Our research demonstrated that miR-32-5p/Golga7 regulated NLRP3 involving in the pyroptosis of chicken splenic cells exposed to ammonia. Our study provided a valuable foundation for the prevention and treatment chickens ammonia poisoning in the livestock production.

CRLF1 bridges AKT and mTORC2 through SIN1 to inhibit pyroptosis and enhance chemo-resistance in ovarian cancer

Ovarian cancer, the second most leading cause of gynecologic cancer mortality worldwide, is challenged by chemotherapy resistance, presenting a significant hurdle. Pyroptosis, an inflammation-linked programmed cell death mediated by gasdermins, has been shown to impact chemoresistance when dysregulated. However, the mechanisms connecting pyroptosis to chemotherapy resistance in ovarian cancer are unclear. We found that cytokine receptor-like factor 1 (CRLF1) is a novel component of mTORC2, enhancing AKT Ser473 phosphorylation through strengthening the interaction between AKT and stress-activated protein kinase interacting protein 1 (SIN1), which in turn inhibits the mitogen-activated protein kinase kinase kinase 5 (ASK1)-JNK-caspase-3-gasdermin E pyroptotic pathway and ultimately confers chemoresistance. High CRLF1-expressing tumors showed sensitivity to AKT inhibition but tolerance to cisplatin. Remarkably, overexpression of binding-defective CRLF1 variants impaired AKT-SIN1 interaction, promoting pyroptosis and chemosensitization. Thus, CRLF1 critically regulates chemoresistance in ovarian cancer by modulating AKT/SIN1-dependent pyroptosis. Binding-defective CRLF1 variants could be developed as tumor-specific polypeptide drugs to enhance chemotherapy for ovarian cancer.

Mechanisms of chondrocyte cell death in osteoarthritis: implications for disease progression and treatment

Osteoarthritis (OA) is a chronic joint disease characterized by the degeneration, destruction, and excessive ossification of articular cartilage. The prevalence of OA is rising annually, concomitant with the aging global population and increasing rates of obesity. This condition imposes a substantial and escalating burden on individual health, healthcare systems, and broader social and economic frameworks. The etiology of OA is multifaceted and not fully understood. Current research suggests that the death of chondrocytes, encompassing mechanisms such as cellular apoptosis, pyroptosis, autophagy, ferroptosis and cuproptosis, contributes to both the initiation and progression of the disease. These cell death pathways not only diminish the population of chondrocytes but also exacerbate joint damage through the induction of inflammation and other deleterious processes. This paper delineates the morphological characteristics associated with various modes of cell death and summarizes current research results on the molecular mechanisms of different cell death patterns in OA. The objective is to review the advancements in understanding chondrocyte cell death in OA, thereby offering novel insights for potential clinical interventions.

Cell Death: Mechanisms and Potential Targets in Breast Cancer Therapy

Breast cancer (BC) has become the most life-threatening cancer to women worldwide, with multiple subtypes, poor prognosis, and rising mortality. The molecular heterogeneity of BC limits the efficacy and represents challenges for existing therapies, mainly due to the unpredictable clinical response, the reason for which probably lies in the interactions and alterations of diverse cell death pathways. However, most studies and drugs have focused on a single type of cell death, while the therapeutic opportunities related to other cell death pathways are often neglected. Therefore, it is critical to identify the predominant type of cell death, the transition to different cell death patterns during treatment, and the underlying regulatory mechanisms in BC. In this review, we summarize the characteristics of various forms of cell death, including PANoptosis (pyroptosis, apoptosis, necroptosis), autophagy, ferroptosis, and cuproptosis, and discuss their triggers and signaling cascades in BC, which may provide a reference for future pathogenesis research and allow for the development of novel targeted therapeutics in BC.

Aerobic Exercise Attenuates Doxorubicin-Induced Cardiomyopathy by Suppressing NLRP3 Inflammasome Activation in a Rat Model

Doxorubicin (DOX) is a potent chemotherapeutic agent with well-documented dose-dependent cardiotoxicity. Regular exercise is recognized for its cardioprotective effects against DOX-induced cardiac inflammation, although the precise mechanisms remain incompletely understood. The activation of inflammasomes has been implicated in the pathogenesis and treatment of DOX-induced cardiotoxicity, with the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome emerging as a key mediator in cardiovascular inflammation. This study aimed to investigate the role of exercise in modulating the NLRP3 inflammasome to protect against DOX-induced cardiac inflammation. Male Sprague-Dawley rats were randomly assigned to receive a 10-day course of DOX or saline injections, with or without a preceding 10-week treadmill running regimen. Cardiovascular function and histological changes were subsequently evaluated. DOX-induced cardiotoxicity was characterized by cardiac atrophy, systolic dysfunction, and hypotension, alongside activation of the NLRP3 inflammasome. Our findings revealed that regular exercise preserved cardiac mass and hypertrophic indices and prevented DOX-induced cardiac dysfunction, although it did not fully preserve blood pressure. These results underscore the significant cardioprotective effects of exercise against DOX-induced cardiotoxicity. While regular exercise did not entirely prevent DOX-induced hypotension, our findings demonstrate that it confers protection against DOX-induced cardiotoxicity by suppressing NLRP3 inflammasome activation in the heart, underscoring its anti-inflammatory role. Further research should explore the temporal dynamics and interactions among exercise, pyroptosis, and other pathways in DOX-induced cardiotoxicity to enhance translational applications in cardiovascular medicine.

Ubiquitination in pyroptosis pathway: A potential therapeutic target for sepsis

Sepsis remains a significant clinical challenge, causing numerous deaths annually and representing a major global health burden. Pyroptosis, a unique form of programmed cell death characterized by cell lysis and the release of inflammatory mediators, is a crucial factor in the pathogenesis and progression of sepsis, septic shock, and organ dysfunction. Ubiquitination, a key post-translational modification influencing protein fate, has emerged as a promising target for managing various inflammatory conditions, including sepsis. This review integrates the current knowledge on sepsis, pyroptosis, and the ubiquitin system, focusing on the molecular mechanisms of ubiquitination within pyroptotic pathways activated during sepsis. By exploring how modulating ubiquitination can regulate pyroptosis and its associated inflammatory signaling pathways, this review provides insights into potential therapeutic strategies for sepsis, highlighting the need for further research into these complex molecular networks.

Small-molecule GSDMD agonism in tumors stimulates antitumor immunity without toxicity

Gasdermin-mediated inflammatory cell death (pyroptosis) can activate protective immunity in immunologically cold tumors. Here, we performed a high-throughput screen for compounds that could activate gasdermin D (GSDMD), which is expressed widely in tumors. We identified 6,7-dichloro-2-methylsulfonyl-3-N-tert-butylaminoquinoxaline (DMB) as a direct and selective GSDMD agonist that activates GSDMD pore formation and pyroptosis without cleaving GSDMD. In mouse tumor models, pulsed and low-level pyroptosis induced by DMB suppresses tumor growth without harming GSDMD-expressing immune cells. Protection is immune-mediated and abrogated in mice lacking lymphocytes. Vaccination with DMB-treated cancer cells protects mice from secondary tumor challenge, indicating that immunogenic cell death is induced. DMB treatment synergizes with anti-PD-1. DMB treatment does not alter circulating proinflammatory cytokine or leukocyte numbers or cause weight loss. Thus, our studies reveal a strategy that relies on a low level of tumor cell pyroptosis to induce antitumor immunity and raise the possibility of exploiting pyroptosis without causing overt toxicity.

Baicalin inhibits PANoptosis by blocking mitochondrial Z-DNA formation and ZBP1-PANoptosome assembly in macrophages

PANoptosis is an emerging form of regulated cell death (RCD) characterized by simultaneous activation of pyroptotic, apoptotic, and necroptotic signaling that not only participates in pathologies of inflammatory diseases but also has a critical role against pathogenic infections. Targeting PANoptosis represents a promising therapeutic strategy for related inflammatory diseases, but identification of inhibitors for PANoptosis remains an unmet demand. Baicalin () is an active flavonoid isolated from Scutellaria baicalensis Georgi (Huangqin), a traditional Chinese medicinal herb used for heat-clearing and detoxifying. Numerous studies suggest that baicalin possesses inhibitory activities on various forms of RCD including apoptosis/secondary necrosis, pyroptosis, and necroptosis, thereby mitigating inflammatory responses. In this study we investigated the effects of baicalin on PANoptosis in macrophage cellular models. Primary macrophages (BMDMs) or J774A.1 macrophage cells were treated with 5Z-7-oxozeaenol (OXO, an inhibitor for TAK1) in combination with TNF-α or LPS. We showed that OXO plus TNF-α or LPS induced robust lytic cell death, which was dose-dependently inhibited by baicalin (50-200 μM). We demonstrated that PANoptosis induction was accompanied by overt mitochondrial injury, mitochondrial DNA (mtDNA) release and Z-DNA formation. Z-DNA was formed from cytosolic oxidized mtDNA. Both oxidized mtDNA and mitochondrial Z-DNA puncta were co-localized with the PANoptosome (including ZBP1, RIPK3, ASC, and caspase-8), a platform for mediating PANoptosis. Intriguingly, baicalin not only prevented mitochondrial injury but also blocked mtDNA release, Z-DNA formation and PANoptosome assembly. Knockdown of ZBP1 markedly decreased PANoptotic cell death. In a mouse model of hemophagocytic lymphohistiocytosis (HLH), administration of baicalin (200 mg/kg, i.g., for 4 times) significantly mitigated lung and liver injury and reduced levels of serum TNF-α and IFN-γ, concomitant with decreased levels of PANoptosis hallmarks in these organs. Baicalin also abrogated the hallmarks of PANoptosis in liver-resident macrophages (Kupffer cells) in HLH mice. Collectively, our results demonstrate that baicalin inhibits PANoptosis in macrophages by blocking mitochondrial Z-DNA formation and ZBP1-PANoptosome assembly, thus conferring protection against inflammatory diseases. PANoptosis is a form of regulated cell death displaying simultaneous activation of pyroptotic, apoptotic, and necroptotic signaling. This study shows that induction of PANoptosis is linked to mitochondrial dysfunction and mitochondrial Z-DNA formation. Baicalin inhibits PANoptosis in macrophages in vitro via blocking mitochondrial dysfunction and the mitochondrial Z-DNA formation and thereby impeding the assembly of ZBP1-associated PANoptosome. In a mouse model of hemophagocytic lymphohistiocytosis (HLH), baicalin inhibits the activation of PANoptotic signaling in liver-resident macrophages (Kupffer cells) in vivo, thus mitigating systemic inflammation and multiple organ injury in mice.

Euphohelioscopin A enhances NK cell antitumor immunity through GSDME-triggered pyroptosis

Immune evasion by cancer cells poses a significant challenge for natural killer cell-based immunotherapy. Pyroptosis, a newly discovered form of programmed cell death, has shown great potential for enhancing the antitumor immunity of natural killer cells. Consequently, targeting pyroptosis has become an attractive strategy for boosting natural killer cell activity against cancer. In this study, various assays were conducted, including natural killer cell cytotoxicity assays, flow cytometry, xenograft tumor models, real-time polymerase chain reaction, and enzyme-linked immunosorbent assay, to assess natural killer cell-mediated cell killing, as well as gene and protein expressions. The results indicated that euphohelioscopin A, a potential pyroptosis activator, enhances natural killer cell-mediated lysis of tumor cells, resulting in inhibiting tumor growth that could be reversed by natural killer cell depletion. Furthermore, we found that euphohelioscopin A significantly enhanced IFNγ production in natural killer cells and synergistically upregulated GSDME with IFNγ in cancer cells. Euphohelioscopin A also increased the cleavage of GSDME, promoting granzyme B-induced pyroptosis, which could be reversed by GSDME knockdown and IFNγ blockade. Overall, the findings suggested that euphohelioscopin A enhanced natural killer cell-mediated killing of cancer cells by triggering pyroptosis, making euphohelioscopin A a promising pyroptosis activator with great potential for use in natural killer cell-based cancer immunotherapy.

Pharmacological inhibition of cGAS ameliorates postoperative cognitive dysfunction by suppressing caspase-3/GSDME-dependent pyroptosis

Neuroinflammation is a major driver of postoperative cognitive dysfunction (POCD). The cyclic GMP-AMP synthase-stimulator of interferon gene (cGAS-STING) signaling is a prominent alarming device for aberrant double-stranded DNA (dsDNA) that has emerged as a key mediator of neuroinflammation in cognitive-related diseases. However, the role of the cGAS-STING pathway in the pathogenesis of POCD remains unclear. A POCD model was developed in male C57BL/6J mice by laparotomy under isoflurane (Iso) anesthesia. The cGAS inhibitor RU.521 and caspase-3 agonist Raptinal were delivered by intraperitoneal administration. BV2 cells were exposed to Iso and lipopolysaccharide (LPS) in the absence or presence of RU.521, and then cocultured with HT22 cells in the absence or presence of Raptinal. Cognitive function was assessed using the Morris water maze test and novel object recognition test. Immunofluorescence assays were used to observe the colocalization of dsDNA and cGAS. The downstream proteins and pro-inflammatory cytokines were detected using the Western blot and enzyme-linked immunosorbent assay (ELISA). Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining was used to assess the degree of cell death in the hippocampus following anesthesia/surgery treatment. Isoflurane/laparotomy and Iso + LPS significantly augmented the levels of cGAS in the hippocampus and BV2 cells, accompanied by mislocalized dsDNA accumulation in the cytoplasm. RU.521 alleviated cognitive impairment, diminished the levels of 2'3'-cGAMP, cGAS, STING, phosphorylated NF-κB p65 and NF-κB-pertinent pro-inflammatory cytokines (TNFα and IL-6), and repressed pyroptosis-associated elements containing cleaved caspase-3, N-GSDME, IL-1β and IL-18. These phenotypes could be rescued by Raptinal in vivo and in vitro. These findings suggest that pharmacological inhibition of cGAS mitigates neuroinflammatory burden of POCD by dampening caspase-3/GSDME-dependent pyroptosis, providing a potential therapeutic strategy for POCD.

CircPDIA3/miR-449a/XBP1 feedback loop curbs pyroptosis by inhibiting palmitoylation of the GSDME-C domain to induce chemoresistance of colorectal cancer

Although oxaliplatin (OXA) is widely used in the frontline treatment of colorectal cancer (CRC), CRC recurrence is commonly observed due to OXA resistance. OXA resistance is associated with a number of factors, including abnormal regulation of pyroptosis. It is therefore important to elucidate the abnormal regulatory mechanism underlying pyroptosis. Here, we identified that the circular RNA circPDIA3 played an important role in chemoresistance in CRC. CircPDIA3 could induce chemoresistance in CRC by inhibiting pyroptosis both in vitro and in vivo. Mechanistically, RIP, RNA pull-down and co-IP assays revealed that circPDIA3 directly bonded to the GSDME-C domain, subsequently enhanced the autoinhibitory effect of the GSDME-C domain through blocking the GSDME-C domain palmitoylation by ZDHHC3 and ZDHHC17, thereby restraining pyroptosis. Additionally, it was found that the circPDIA3/miR-449a/XBP1 positive feedback loop increased the expression of circPDIA3 to induce chemoresistance. Furthermore, our clinical data and patient-derived tumor xenograft (PDX) models supported the positive association of circPDIA3 with development of chemoresistance in CRC patients. Taken together, our findings demonstrated that circPDIA3 could promote chemoresistance by amplifying the autoinhibitory effect of the GSDME-C domain through inhibition of the GSDME-C domain palmitoylation in CRC. This study provides novel insights into the mechanism of circRNA in regulating pyroptosis and providing a potential therapeutic target for reversing chemoresistance of CRC.

Cpeb4-mediated Dclk2 promotes neuronal pyroptosis induced by chronic cerebral ischemia through phosphorylation of Ehf

Chronic cerebral ischemia (CCI) is a clinical syndrome characterised by brain dysfunction due to decreased chronic cerebral perfusion. CCI initiates several inflammatory pathways, including pyroptosis. RNA-binding proteins (RBPs) play important roles in CCI. This study aimed to explore whether the interaction between RBP-Cpeb4 and Dclk2 affected Ehf phosphorylation to regulate neuronal pyroptosis. HT22 cells and mice were used to construct oxygen glucose deprivation (OGD)/CCI models. We found that Cpeb4 and Dclk2 were upregulated in OGD-treated HT22 cells and CCI-induced hippocampal CA1 tissues. Cpeb4 upregulated Dclk2 expression by increasing Dclk2 mRNA stability. Knockdown of Cpeb4 or Dclk2 inhibited neuronal pyroptosis in OGD-treated HT22 cells and CCI-induced hippocampal CA1 tissues. By binding to the promoter regions of Caspase1 and Caspase3, the transcription factor Ehf reduced their promoter activities and inhibited the transcription. Dclk2 phosphorylated Ehf and changed its nucleoplasmic distribution, resulting in the exit of p-Ehf from the nucleus and decreased Ehf levels. It promoted the expression of Caspase1 and Caspase3 and stimulated neuronal pyroptosis of HT22 cells induced by OGD. Cpeb4/Dclk2/Ehf pathway plays an important role in the regulation of cerebral ischemia-induced neuronal pyroptosis.

HDAC inhibitor regulates the tumor immune microenvironment via pyroptosis in triple negative breast cancer

Pyroptosis, an inflammatory form of cell death, promotes the release of immunogenic substances and stimulates immune cell recruitment, a process, which could turn cold tumors into hot ones. Thus, instigating pyroptosis in triple-negative breast cancer (TNBC) serves as a viable method for restoring antitumor immunity. We analyzed the effects of Histone Deacetylase Inhibitors (HDACi) on TNBC cells using the Cell Counting Kit-8 and colony formation assay. Apoptosis and lactate dehydrogenase (LDH) release assays were utilized to determine the form of cell death. The pyroptotic executor was validated by quantitative real-time polymerase chain reaction and western blot. Transcriptome was analyzed to investigate pyroptosis-inducing mechanisms. A subcutaneously transplanted tumor model was generated in BALB/c mice to evaluate infiltration of immune cells. HDACi significantly diminished cell proliferation, and pyroptotic "balloon"-like cells became apparent. HDACi led to an intra and extracellular material exchange, signified by the release of LDH and the uptake of propidium iodide. Among the gasdermin family, TNBC cells expressed maximum quantities of GSDME, and expression of GSDMA, GSDMB, and GSDME were augmented post HDACi treatment. Pyroptosis was instigated via the activation of the caspase 3-GSDME pathway with the potential mechanisms being cell cycle arrest and altered intracellular REDOX balance due to aberrant glutathione metabolism. In vivo experiments demonstrated that HDACi can activate pyroptosis, limit tumor growth, and escalate CD8+ lymphocyte and CD11b+ cell infiltration along with an increased presence of granzyme B in tumors. HDACi can instigate pyroptosis in TNBC, promoting infiltration of immune cells and consequently intensifying the efficacy of anticancer immunity.

Gasdermin D and Gasdermin E Are Dispensable for Silica-Mediated IL-1β Secretion from Mouse Macrophages

Silica crystals activate the NLRP3 inflammasome in macrophages, resulting in the caspase-1-dependent secretion of the proinflammatory cytokine IL-1β. Caspase-1-mediated cleavage of gasdermin D (GSDMD) triggers the formation of GSDMD pores, which drive pyroptotic cell death and facilitate the rapid release of IL-1β. However, the role of GSDMD in silica-induced lung injury is unclear. In this study, we show that although silica-induced lung injury is dependent on the inflammasome adaptor ASC and IL-1R1 signaling, GSDMD is dispensable for acute lung injury. Although the early rapid secretion of IL-1β in response to ATP and nigericin was GSDMD dependent, GSDMD was not required for IL-1β release at later time points. Similarly, secretion of IL-1β from macrophages in response to silica and alum proceeded in a GSDMD-independent manner. We further found that gasdermin E did not contribute to macrophage IL-1β secretion in the absence of GSDMD in vitro and was also not necessary for silica-induced acute lung injury in vivo. These findings demonstrate that GSDMD and gasdermin E are dispensable for IL-1β secretion in response to silica in vitro and in silica-induced acute lung injury in vivo.

Gasdermins as evolutionarily conserved executors of inflammation and cell death

The gasdermins are a family of pore-forming proteins that have recently emerged as executors of pyroptosis, a lytic form of cell death that is induced by the innate immune system to eradicate infected or malignant cells. Mammalian gasdermins comprise a cytotoxic N-terminal domain, a flexible linker and a C-terminal repressor domain. Proteolytic cleavage in the linker releases the cytotoxic domain, thereby allowing it to form β-barrel membrane pores. Formation of gasdermin pores in the plasma membrane eventually leads to a loss of the electrochemical gradient, cell death and membrane rupture. Here we review recent work that has expanded our understanding of gasdermin biology and function in mammals by revealing their activation mechanism, their regulation and their roles in autoimmunity, host defence and cancer. We further highlight fungal and bacterial gasdermin pore formation pointing to a conserved mechanism of cell death induction.

Full-length GSDME mediates pyroptosis independent from cleavage

Gasdermin (GSDM) family proteins, known as the executors of pyroptosis, undergo protease-mediated cleavage before inducing pyroptosis. We here discovered a form of pyroptosis mediated by full-length (FL) GSDME without proteolytic cleavage. Intense ultraviolet-C irradiation-triggered DNA damage activates nuclear PARP1, leading to extensive formation of poly(ADP-ribose) (PAR) polymers. These PAR polymers are released to the cytoplasm, where they activate PARP5 to facilitate GSDME PARylation, resulting in a conformational change in GSDME that relieves autoinhibition. Moreover, ultraviolet-C irradiation promotes cytochrome c-catalysed cardiolipin peroxidation to elevate lipid reactive oxygen species, which is then sensed by PARylated GSDME, leading to oxidative oligomerization and plasma membrane targeting of FL-GSDME for perforation, eventually inducing pyroptosis. Reagents that concurrently stimulate PARylation and oxidation of FL-GSDME, synergistically promoting pyroptotic cell death. Overall, the present findings elucidate an unreported mechanism underlying the cleavage-independent function of GSDME in executing cell death, further enriching the paradigms and understanding of FL-GSDME-mediated pyroptosis.

Polyester nanoparticles delivering chemotherapeutics: Learning from the past and looking to the future to enhance their clinical impact in tumor therapy

Polymeric nanoparticles (NPs), specifically those comprised of biodegradable and biocompatible polyesters, have been heralded as a game-changing drug delivery platform. In fact, poly(α-hydroxy acids) such as polylactide (PLA), poly(lactide-co-glycolide) (PLGA), and poly(ε-caprolactone) (PCL) have been heavily researched in the past three decades as the material basis of polymeric NPs for drug delivery applications. As materials, these polymers have found success in resorbable sutures, biodegradable implants, and even monolithic, biodegradable platforms for sustained release of therapeutics (e.g., proteins and small molecules) and diagnostics. Few fields have gained more attention in drug delivery through polymeric NPs than cancer therapy. However, the clinical translational of polymeric nanomedicines for treating solid tumors has not been congruent with the fervor or funding in this particular field of research. Here, we attempt to provide a comprehensive snapshot of polyester NPs in the context of chemotherapeutic delivery. This includes a preliminary exploration of the polymeric nanomedicine in the cancer research space. We examine the various processes for producing polyester NPs, including methods for surface-functionalization, and related challenges. After a detailed overview of the multiple factors involved with the delivery of NPs to solid tumors, the crosstalk between particle design and interactions with biological systems is discussed. Finally, we report state-of-the-art approaches toward effective delivery of NPs to tumors, aiming at identifying new research areas and re-evaluating the reasons why some research avenues have underdelivered. We hope our effort will contribute to a better understanding of the gap to fill and delineate the future research work needed to bring polyester-based NPs closer to clinical application. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Mitochondria and cell death

Mitochondria are cellular factories for energy production, calcium homeostasis and iron metabolism, but they also have an unequivocal and central role in intrinsic apoptosis through the release of cytochrome c. While the subsequent activation of proteolytic caspases ensures that cell death proceeds in the absence of collateral inflammation, other phlogistic cell death pathways have been implicated in using, or engaging, mitochondria. Here we discuss the emerging complexities of intrinsic apoptosis controlled by the BCL-2 family of proteins. We highlight the emerging theory that non-lethal mitochondrial apoptotic signalling has diverse biological roles that impact cancer, innate immunity and ageing. Finally, we delineate the role of mitochondria in other forms of cell death, such as pyroptosis, ferroptosis and necroptosis, and discuss mitochondria as central hubs for the intersection and coordination of cell death signalling pathways, underscoring their potential for therapeutic manipulation.

Innate immune sensing of cell death in disease and therapeutics

Innate immunity, cell death and inflammation underpin many aspects of health and disease. Upon sensing pathogens, pathogen-associated molecular patterns or damage-associated molecular patterns, the innate immune system activates lytic, inflammatory cell death, such as pyroptosis and PANoptosis. These genetically defined, regulated cell death pathways not only contribute to the host defence against infectious disease, but also promote pathological manifestations leading to cancer and inflammatory diseases. Our understanding of the underlying mechanisms has grown rapidly in recent years. However, how dying cells, cell corpses and their liberated cytokines, chemokines and inflammatory signalling molecules are further sensed by innate immune cells, and their contribution to further amplify inflammation, trigger antigen presentation and activate adaptive immunity, is less clear. Here, we discuss how pattern-recognition and PANoptosome sensors in innate immune cells recognize and respond to cell-death signatures. We also highlight molecular targets of the innate immune response for potential therapeutic development.

A new insight into the mechanism of dichlorodiphenyltrichloroethane-induced hepatotoxicity based on GSDME-mediated pyroptosis

There have been persistent concerns about the safety risks associated with DDT residues in the environment. Studies have shown that exposure to DDT or its metabolites can cause various liver diseases. However, the mechanisms of liver toxicity haven't been well studied. In our current investigation, we observed that DDT triggers pyroptosis in human liver cells (HL-7702), representing a novel form of programmed cell death. Our results delineated DDT (0-100 μM) induced pyroptosis in HL-7702 cells, which was confirmed through morphological changes, lactate dehydrogenase (LDH) release, gasdermin E (GSDME) cleavage and Annexin-V/PI staining. Knockdown of GSDME reduced cell death and transferred the mode of cell death from pyroptosis to apoptosis. Notably, DDT exposure markedly increased reactive oxygen species (ROS) production, concurrent with c-Jun N-terminal kinase (JNK) phosphorylation. Intervention with a ROS inhibitor or JNK inhibitor SP600125 restored cell viability and hindered GSDME-mediated pyroptosis. Our results firstly demonstrate that DDT suppresses HL-7702 cells growth by inducing pyroptosis mainly through the ROS/JNK/GSDME pathway. These findings not only contribute to an in-depth understanding of DDT toxicity but also open avenues for gaining valuable insights into potential mitigation strategies and therapeutic interventions.

Pyroptotic-Spatiotemporally Selective Delivery of siRNA against Pyroptosis and Autoimmune Diseases

Small-interfering RNAs (siRNAs) offer promising prospects for treating pyroptosis-related autoimmune diseases. However, poor stability and off-target effects during in vivo transportation hinder their practical clinical applications. Precision delivery and adaptive release of siRNAs into inflamed tissues and immune cells could unleash their full therapeutic potential. This study establishes a pyroptotic-spatiotemporally selective siRNA delivery system (PMRC@siGSDME) that selectively targets inflammatory tissues, responds to pyroptosis, and exhibits remarkable therapeutic efficacy against various autoimmune diseases. Novel hybrid nanovesicles (NVs) are designed as a combination of pyroptotic macrophage membranes (PMs) and R8-cardiolipin-containing nanovesicles (RC-NVs). Evidence provides that PM-derived proteins involved in cell-cell interactions and membrane trafficking may contribute to the specificity of NVs to inflammatory tissue. In addition, cardiolipin anchored in the hybrid NVs increases its affinity for activated gasdermin E (GSDME) and achieves pyroptosis-adaptive release of siGSDME for the spatiotemporally selective suppression of immune responses. More importantly, PMRC@siGSDME displays significant anti-inflammatory and therapeutic effects in multiple mouse autoimmune disease models, including arthritis and inflammatory bowel disease (IBD). Collectively, an innovative siRNA delivery strategy precisely tailored for pyroptotic cells has been developed, paving the way for new treatments for autoimmune inflammatory diseases with minimal side effects and wide clinical applicability.

Recent advances in caspase-3, breast cancer, and traditional Chinese medicine: a review

Caspases (cysteinyl aspartate-specific proteinases) are a group of structurally similar proteases in the cytoplasm that can be involved in cell differentiation, programmed death, proliferation, and inflammatory generation. Experts have found that caspase-3 can serve as a terminal splicing enzyme in apoptosis and participate in the mechanism by which cytotoxic drugs kill cancer cells. Breast cancer (BC) has become the most common cancer among women worldwide, posing a severe threat to their lives. Finding new therapeutic targets for BC is the primary task of contemporary physicians. Numerous studies have revealed the close association between caspase-3 expression and BC. Caspase-3 is essential in BC's occurrence, invasion, and metastasis. In addition, Caspase-3 exerts anticancer effects by regulating cell death mechanisms. Traditional Chinese medicine acting through caspase-3 expression is increasingly used in clinical treatment. This review summarizes the biological mechanism of caspase-3 and research progress on BC. It introduces a variety of traditional Chinese medicine related to caspase-3 to provide new ideas for the clinical treatment of BC.

AI-powered omics-based drug pair discovery for pyroptosis therapy targeting triple-negative breast cancer

Due to low success rates and long cycles of traditional drug development, the clinical tendency is to apply omics techniques to reveal patient-level disease characteristics and individualized responses to treatment. However, the heterogeneous form of data and uneven distribution of targets make drug discovery and precision medicine a non-trivial task. This study takes pyroptosis therapy for triple-negative breast cancer (TNBC) as a paradigm and uses data mining of a large TNBC cohort and drug databases to establish a biofactor-regulated neural network for rapidly screening and optimizing compound pyroptosis drug pairs. Subsequently, biomimetic nanococrystals are prepared using the preferred combination of mitoxantrone and gambogic acid for rational drug delivery. The unique mechanism of obtained nanococrystals regulating pyroptosis genes through ribosomal stress and triggering pyroptosis cascade immune effects are revealed in TNBC models. In this work, a target omics-based intelligent compound drug discovery framework explores an innovative drug development paradigm, which repurposes existing drugs and enables precise treatment of refractory diseases.

Synthetic lethality of combined ULK1 defection and p53 restoration induce pyroptosis by directly upregulating GSDME transcription and cleavage activation through ROS/NLRP3 signaling

BACKGROUND

High expression of ubiquitin ligase MDM2 is a primary cause of p53 inactivation in many tumors, making it a promising therapeutic target. However, MDM2 inhibitors have failed in clinical trials due to p53-induced feedback that enhances MDM2 expression. This underscores the urgent need to find an effective adaptive genotype or combination of targets.

METHODS

Kinome-wide CRISPR/Cas9 knockout screen was performed to identify genes that modulate the response to MDM2 inhibitor using TP53 wild type cancer cells and found ULK1 as a candidate. The MTT cell viability assay, flow cytometry and LDH assay were conducted to evaluate the activation of pyroptosis and the synthetic lethality effects of combining ULK1 depletion with p53 activation. Dual-luciferase reporter assay and ChIP-qPCR were performed to confirm that p53 directly mediates the transcription of GSDME and to identify the binding region of p53 in the promoter of GSDME. ULK1 knockout / overexpression cells were constructed to investigate the functional role of ULK1 both in vitro and in vivo. The mechanism of ULK1 depletion to activate GSMDE was mainly investigated by qPCR, western blot and ELISA.

RESULTS

By using high-throughput screening, we identified ULK1 as a synthetic lethal gene for the MDM2 inhibitor APG115. It was determined that deletion of ULK1 significantly increased the sensitivity, with cells undergoing typical pyroptosis. Mechanistically, p53 promote pyroptosis initiation by directly mediating GSDME transcription that induce basal-level pyroptosis. Moreover, ULK1 depletion reduces mitophagy, resulting in the accumulation of damaged mitochondria and subsequent increasing of reactive oxygen species (ROS). This in turn cleaves and activates GSDME via the NLRP3-Caspase inflammatory signaling axis. The molecular cascade makes ULK1 act as a crucial regulator of pyroptosis initiation mediated by p53 activation cells. Besides, mitophagy is enhanced in platinum-resistant tumors, and ULK1 depletion/p53 activation has a synergistic lethal effect on these tumors, inducing pyroptosis through GSDME directly.

CONCLUSION

Our research demonstrates that ULK1 deficiency can synergize with MDM2 inhibitors to induce pyroptosis. p53 plays a direct role in activating GSDME transcription, while ULK1 deficiency triggers upregulation of the ROS-NLRP3 signaling pathway, leading to GSDME cleavage and activation. These findings underscore the pivotal role of p53 in determining pyroptosis and provide new avenues for the clinical application of p53 restoration therapies, as well as suggesting potential combination strategies.

Long non-coding RNAs in ferroptosis, pyroptosis and necroptosis: from functions to clinical implications in cancer therapy

As global population ageing accelerates, cancer emerges as a predominant cause of mortality. Long non-coding RNAs (lncRNAs) play crucial roles in cancer cell growth and death, given their involvement in regulating downstream gene expression levels and numerous cellular processes. Cell death, especially non-apoptotic regulated cell death (RCD), such as ferroptosis, pyroptosis and necroptosis, significantly impacts cancer proliferation, invasion and metastasis. Understanding the interplay between lncRNAs and the diverse forms of cell death in cancer is imperative. Modulating lncRNA expression can regulate cancer onset and progression, offering promising therapeutic avenues. This review discusses the mechanisms by which lncRNAs modulate non-apoptotic RCDs in cancer, highlighting their potential as biomarkers for various cancer types. Elucidating the role of lncRNAs in cell death pathways provides valuable insights for personalised cancer interventions.

Dual roles of inflammatory programmed cell death in cancer: insights into pyroptosis and necroptosis

Programmed cell death (PCD) is essential for cellular homeostasis and defense against infections, with inflammatory forms like pyroptosis and necroptosis playing significant roles in cancer. Pyroptosis, mediated by caspases and gasdermin proteins, leads to cell lysis and inflammatory cytokine release. It has been implicated in various diseases, including cancer, where it can either suppress tumor growth or promote tumor progression through chronic inflammation. Necroptosis, involving RIPK1, RIPK3, and MLKL, serves as a backup mechanism when apoptosis is inhibited. In cancer, necroptosis can enhance immune responses or contribute to tumor progression. Both pathways have dual roles in cancer, acting as tumor suppressors or promoting a pro-tumorigenic environment depending on the context. This review explores the molecular mechanisms of pyroptosis and necroptosis, their roles in different cancers, and their potential as therapeutic targets. Understanding the context-dependent effects of these pathways is crucial for developing effective cancer therapies.

Iridium(III) Photosensitizers Induce Simultaneous Pyroptosis and Ferroptosis for Multi-Network Synergistic Tumor Immunotherapy

The integration of pyroptosis and ferroptosis hybrid cell death induction to augment immune activation represents a promising avenue for anti-tumor treatment, but there is a lack of research. Herein, we developed two iridium (III)-triphenylamine photosensitizers, IrC and IrF, with the capacity to disrupt redox balance and induce photo-driven cascade damage to DNA and Kelch-like ECH-associated protein 1 (KEAP1). The activation of the absent in melanoma 2 (AIM2)-related cytoplasmic nucleic acid-sensing pathway, triggered by damaged DNA, leads to the induction of gasdermin D (GSDMD)-mediated pyroptosis. Simultaneously, iron homeostasis, regulated by the KEAP1/nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase 1 (HO-1) pathway, serves as a pivotal bridge, facilitating not only the induction of gasdermin E (GSDME)-mediated non-canonical pyroptosis, but also ferroptosis in synergy with glutathione peroxidase 4 (GPX4) depletion. The collaborative action of pyroptosis and ferroptosis generates a synergistic effect that elicits immunogenic cell death, stimulates a robust immune response and effectively inhibits tumor growth in vivo. Our work introduces the first metal-based small molecule dual-inducers of pyroptosis and ferroptosis for potent cancer immunotherapy, and highlights the significance of iron homeostasis as a vital hub connecting synergistic effects of pyroptosis and ferroptosis.

Macrophage membrane-based biomimetic nanocarrier system for enhanced immune activation and combination therapy in liver cancer

Previous studies have demonstrated that the combination of photodynamic therapy, photothermal therapy and chemotherapy is highly effective in treating hepatocellular carcinoma (HCC). However, the clinical application of this approach has been hindered by the lack of efficient and low-toxicity drug delivery platforms. To address this issue, we developed a novel biomimetic nanocarrier platform named ZID@RM, which utilizes ZIF8 functional nanoparticles encapsulated with macrophage membrane and loaded with indocyanine green and doxorubicin. The bionic nanocarrier platform has good biocompatibility, reducing the risk of rapid clearance by macrophages and improving the targeting ability for HCC cells. Under the dual regulation of acidity and infrared light, ZID@RM stimulated the generation of abundant reactive oxygen species within HCC cells, induced tumor cell pyroptosis and promoted the release of damage-associated molecular patterns to induce immune responses. In the future, this technology platform has the potential to provide personalized and improved healthcare by using patients' own macrophage membranes to create an efficient drug delivery system for tumor therapy.Graphical abstract Scheme 1 Schematic representation of the synthesis of a biomimetic nanomedicine delivery platform (ZID@RM) and its application in tumor imaging-guided combination therapy.

Nanoparticle-mediated cell pyroptosis: a new therapeutic strategy for inflammatory diseases and cancer

Pyroptosis, a lytic form of cell death mediated by the gasdermin family, is characterized by cell swelling and membrane rupture. Inducing pyroptosis in cancer cells can enhance antitumor immune responses and is a promising strategy for cancer therapy. However, excessive pyroptosis may trigger the development of inflammatory diseases due to immoderate and continuous inflammatory reactions. Nanomaterials and nanobiotechnology, renowned for their unique advantages and diverse structures, have garnered increasing attention owing to their potential to induce pyroptosis in diseases such as cancer. A nano-delivery system for drug-induced pyroptosis in cancer cells can overcome the limitations of small molecules. Furthermore, nanomedicines can directly induce and manipulate pyroptosis. This review summarizes and discusses the latest advancements in nanoparticle-based treatments with pyroptosis among inflammatory diseases and cancer, focusing on their functions and mechanisms and providing valuable insights into selecting nanodrugs for pyroptosis. However, the clinical application of these strategies still faces challenges owing to a limited understanding of nanobiological interactions. Finally, future perspectives on the emerging field of pyroptotic nanomaterials are presented.

Icaritin Exerts Anti-Cancer Effects through Modulating Pyroptosis and Immune Activities in Hepatocellular Carcinoma

Icaritin (ICT), a natural compound extracted from the dried leaves of the genus Epimedium, possesses antitumor and immunomodulatory properties. However, the mechanisms through which ICT modulates pyroptosis and immune response in hepatocellular carcinoma (HCC) remain unclear. This study demonstrated that ICT exhibits pyroptosis-inducing and anti-hepatocarcinoma effects. Specifically, the caspase1-GSDMD and caspase3-GSDME pathways were found to be involved in ICT-triggered pyroptosis. Furthermore, ICT promoted pyroptosis in co-cultivation of HepG2 cells and macrophages, regulating the release of inflammatory cytokines and the transformation of macrophages into a proinflammatory phenotype. In the Hepa1-6+Luc liver cancer model, ICT treatment significantly increased the expression of cleaved-caspase1, cleaved-caspase3, and granzyme B, modulated cytokine secretion, and stimulated CD8+ T cell infiltration, resulting in a reduction in tumor growth. In conclusion, the findings in this research suggested that ICT may modulate cell pyroptosis in HCC and subsequently regulate the immune microenvironment of the tumor. These observations may expand the understanding of the pharmacological mechanism of ICT, as well as the therapy of liver cancer.

Pyroptosis in Skeleton Diseases: A Potential Therapeutic Target Based on Inflammatory Cell Death

Skeletal disorders, including fractures, osteoporosis, osteoarthritis, rheumatoid arthritis, and spinal degenerative conditions, along with associated spinal cord injuries, significantly impair daily life and impose a substantial burden. Many of these conditions are notably linked to inflammation, with some classified as inflammatory diseases. Pyroptosis, a newly recognized form of inflammatory cell death, is primarily triggered by inflammasomes and executed by caspases, leading to inflammation and cell death through gasdermin proteins. Emerging research underscores the pivotal role of pyroptosis in skeletal disorders. This review explores the pyroptosis signaling pathways and their involvement in skeletal diseases, the modulation of pyroptosis by other signals in these conditions, and the current evidence supporting the therapeutic potential of targeting pyroptosis in treating skeletal disorders, aiming to offer novel insights for their management.

Terphenyllin induces CASP3-dependent apoptosis and pyroptosis in A375 cells through upregulation of p53

BACKGROUND

Melanoma, one of the most lethal forms of skin cancer, has the potential to develop in any area where melanocytes are present. Currently, postoperative recurrence due to the emergence of systemic drug resistance represents a significant challenge in the treatment of melanoma. In this study, terphenyllin (TER), a distinctive inhibitory impact on melanoma cells was identified from the natural p-terphenyl metabolite. This study aimed to elucidate the intrinsic mechanism of this inhibitory effect, which may facilitate the discovery of novel chemotherapeutic agents.

METHODS

A transcriptome sequencing and metabolomic analysis of TER-treated A375 cells was conducted to identify potential pathways of action. The key proteins were knocked out and backfilled using CRISPR-Cas9 technology and molecular cloning. Subsequently, the results of cytosolic viability, LDH release, immunofluorescence and flow cytometry were employed to demonstrate the cell death status of the drug-treated cells.

RESULTS

The p53 signalling pathway was markedly upregulated following TER treatment, leading to the activation of CASP3 via the intrinsic apoptotic pathway. The activated CASP3 initiated apoptosis, while simultaneously continuing to cleave the GSDME, thereby triggering pyroptosis. The knockout of p53, a key protein situated upstream of this pathway, resulted in a significant rescue of TER-induced cell death, as well as an alleviation of the decrease in cell viability. However, the knockout of key proteins situated downstream of the pathway (CASP3 and GSDME) did not result in a rescue of TER-induced cell death, but rather a transformation of the cells from apoptosis and pyroptosis.

CONCLUSIONS

The induction of apoptosis and pyroptosis in A375 cells by TER is mediated via the p53-BAX/FAS-CASP3-GSDME signalling pathway. This lays the foundation for TER as a potential anti-melanoma drug in the future. It should be noted that CASP3 and GSDME in this pathway solely regulate the mode of cell death, rather than determine whether cell death occurs. This distinction may prove valuable in future studies of apoptosis and pyroptosis.

Electrostimulation Evokes Caspase-3-Activated Fast Cancer Cell Pyroptosis and Its Nuclear Stress Response Pathways

Pyroptosis of programmed cell death has been recognized as a more effective way to inhibit the occurrence and development of tumors than the better-studied apoptosis. However, it is still challenging to quickly and effectively trigger pyroptosis of cancer cells for high-efficacy cancer treatment. Here, we report on the first use of mild constant-potential electrostimulation (cp-ES) to quickly trigger cancer cell pyroptosis with a probability up to ∼91.4% and significantly shortened time (within 1 h), ∼3-6 times faster than typical drug stimulation to induce pyroptosis. We find that the ES-induced cancer cell pyroptosis is through the activated caspase-3 (pathway) cleavage of gasdermin E (GSDME) to form an N-terminal fragment (GSDME-N) and observe nuclear shrinkage and reduction of the number of nucleoli as well as down-/up-regulated expression of two important nucleoproteins of nucleolin and nucleophosmin (NPM1). The study enriches the basic understanding of pyroptosis and provides a new avenue for potential effective treatment of cancer.

Analysis of PANoptosis-related ceRNA network reveals lncRNA MIR17HG involved in osteogenic differentiation inhibition impaired by tumor necrosis factor-α

BACKGROUND

Inflammatory cytokines such as Interleukin 1β(IL1β), IL6,Tumor Necrosis Factor-α (TNF-α) can inhibit osteoblast differentiation and induce osteoblast apoptosis. PANoptosis, a newly identified type of programmed cell death (PCD), may be influenced by long noncoding RNA (lncRNAs) which play important roles in regulating inflammation. However, the potential role of lncRNAs in inflammation and PANoptosis during osteogenic differentiation remains unclear. This study aimed to investigate the regulatory functions of lncRNAs in inflammation and apoptosis during osteogenic differentiation.

METHODS AND RESULTS

High-throughput sequencing was used to identify differentially expressed genes involved in osteoblast differentiation under inflammatory conditions. Two lncRNAs associated with inflammation and PANoptosis during osteogenic differentiation were identified from sequencing data and Gene Expression Omnibus (GEO) databases. Their functionalities were analyzed using diverse bioinformatics methodologies, resulting in the construction of the lncRNA-miRNA-mRNA network. Among these, lncRNA (MIR17HG) showed a high correlation with PANoptosis. Bibliometric methods were employed to collect literature data on PANoptosis, and its components were inferred. PCR and Western Blotting experiments confirmed that lncRNA MIR17HG is related to PANoptosis in osteoblasts during inflammation.

CONCLUSIONS

Our data suggest that TNF-α-induced inhibition of osteogenic differentiation and PANoptosis in MC3T3-E1 osteoblasts is associated with MIR17HG. These findings highlight the critical role of MIR17HG in the interplay between inflammation, PANoptosis, and osteogenic differentiation, suggesting potential therapeutic targets for conditions involving impaired bone formation and inflammatory responses.