The Versatile Gasdermin Family: Their Function and Roles in Diseases

A genomic association study revealing subphenotypes of childhood steroid-sensitive nephrotic syndrome in a larger genomic sequencing cohort

Dissecting the genetic components that contribute to the two main subphenotypes of steroid-sensitive nephrotic syndrome (SSNS) using genome-wide association studies (GWAS) strategy is important for understanding the disease. We conducted a multicenter cohort study (360 patients and 1835 controls) combined with a GWAS strategy to identify susceptibility variants associated with the following two subphenotypes of SSNS: steroid-sensitive nephrotic syndrome without relapse (SSNSWR, 181 patients) and steroid-dependent/frequent relapse nephrotic syndrome (SDNS/FRNS, 179 patients). The distribution of two single-nucleotide polymorphisms (SNPs) in ANKRD36 and ALPG was significant between SSNSWR and healthy controls, and that of two SNPs in GAD1 and HLA-DQA1 was significant between SDNS/FRNS and healthy controls. Interestingly, rs1047989 in HLA-DQA1 was a candidate locus for SDNS/FRNS but not for SSNSWR. No significant SNPs were observed between SSNSWR and SDNS/FRNS. Meanwhile, chromosome 2:171713702 in GAD1 was associated with a greater steroid dose (>0.75 mg/kg/d) upon relapse to first remission in patients with SDNS/FRNS (odds ratio = 3.14; 95% confidence interval, 0.97-9.87; P = 0.034). rs117014418 in APOL4 was significantly associated with a decrease in eGFR of greater than 20% compared with the baseline in SDNS/FRNS patients (P = 0.0001). Protein-protein intersection network construction suggested that HLA-DQA1 and HLA-DQB1 function together through GSDMA. Thus, SSNSWR belongs to non-HLA region-dependent nephropathy, and the HLA-DQA/DQB region is likely strongly associated with disease relapse, especially in SDNS/FRNS. The study provides a novel approach for the GWAS strategy of SSNS and contributes to our understanding of the pathological mechanisms of SSNSWR and SDNS/FRNS.

Pyroptosis in Diabetic Peripheral Neuropathy and its Therapeutic Regulation

Pyroptosis is a pro-inflammatory form of cell death resulting from the activation of gasdermins (GSDMs) pore-forming proteins and the release of several pro-inflammatory factors. However, inflammasomes are the intracellular protein complexes that cleave gasdermin D (GSDMD), leading to the formation of robust cell membrane pores and the initiation of pyroptosis. Inflammasome activation and gasdermin-mediated membrane pore formation are the important intrinsic processes in the classical pyroptotic signaling pathway. Overactivation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome triggers pyroptosis and amplifies inflammation. Current evidence suggests that the overactivation of inflammasomes and pyroptosis may further induce the progression of cancers, nerve injury, inflammatory disorders and metabolic dysfunctions. Current evidence also indicates that pyroptosis-dependent cell death accelerates the progression of diabetes and its frequent consequences including diabetic peripheral neuropathy (DPN). Pyroptosis-mediated inflammatory reaction further exacerbates DPN-mediated CNS injury. Accumulating evidence shows that several molecular signaling mechanisms trigger pyroptosis in insulin-producing cells, further leading to the development of DPN. Numerous studies have suggested that certain natural compounds or drugs may possess promising pharmacological properties by modulating inflammasomes and pyroptosis, thereby offering potential preventive and practical therapeutic approaches for the treatment and management of DPN. This review elaborates on the underlying molecular mechanisms of pyroptosis and explores possible therapeutic strategies for regulating pyroptosis-regulated cell death in the pharmacological treatment of DPN.

Gasdermin D silencing alleviates airway inflammation and remodeling in an ovalbumin-induced asthmatic mouse model

Emerging evidence demonstrates that pyroptosis has been implicated in the pathogenesis of asthma. Gasdermin D (GSDMD) is the pyroptosis executioner. The mechanism of GSDMD in asthma remains unclear. The aim of this study was to elucidate the potential role of GSDMD in asthmatic airway inflammation and remodeling. Immunofluorescence staining was conducted on airway epithelial tissues obtained from both asthma patients and healthy controls (HCs) to evaluate the expression level of N-GSDMD. ELISA was used to measure concentrations of cytokines (IL-1β, IL-18, IL-17A, and IL-10) in serum samples collected from asthma patients and healthy individuals. We demonstrated that N-GSDMD, IL-18, and IL-1β were significantly increased in samples with mild asthma compared with those from the controls. Then, wild type and Gsdmd-knockout (Gsdmd-/-) mice were used to establish asthma model. We performed histopathological staining, ELISA, and flow cytometry to explore the function of GSDMD in allergic airway inflammation and tissue remodeling in vivo. We observed that the expression of N-GSDMD, IL-18, and IL-1β was enhanced in OVA-induced asthma mouse model. Gsdmd knockout resulted in attenuated IL-18, and IL-1β production in both bronchoalveolar lavage fluid (BALF) and lung tissue in asthmatic mice. In addition, Gsdmd-/- mice exhibit a significant reduction in airway inflammation and remodeling, which might be associated with reduced Th17 inflammatory response and M2 polarization of macrophages. Further, we found that GSDMD knockout may improve asthmatic airway inflammation and remodeling through regulating macrophage adhesion, migration, and macrophage M2 polarization by targeting Notch signaling pathway. These findings demonstrate that GSDMD deficiency profoundly alleviates allergic inflammation and tissue remodeling. Therefore, GSDMD may serve as a potential therapeutic target against asthma.

Neobractatin induces pyroptosis of esophageal cancer cells by TOM20/BAX signaling pathway

BACKGROUND

Emerging evidence suggests that pyroptosis, a form of programmed cell death, has been implicated in cancer progression. The involvement of specific proteins in pyroptosis is an area of growing interest. TOM20, an outer mitochondrial membrane protein, has recently garnered attention for its potential role in pyroptosis. Our previous study found that NBT could induce pyroptosis by ROS/JNK pathway in esophageal cancer cells.

PURPOSE

This study aims to investigate whether NBT induces pyroptosis and verify whether such effects are involved in up-regulation of TOM20 in esophageal cancer cells.

METHODS

The University of ALabama at Birmingham CANcer data analysis Portal (UALCAN) was used to analyze the clinical significance of GSDME in esophageal cancer. MTT assay, morphological observation and Western blot were performed to verify the roles of TOM20 and BAX in NBT-induced pyroptosis after CRISPR-Cas9-mediated knockout. Immunofluorescence was used to determine the subcellular locations of BAX and cytochrome c. MitoSOX Red was employed to assess the mitochondrial reactive oxygen species (ROS) level. KYSE450 and TOM20 knockout KYSE450-/- xenograft models were established to elucidate the mechanisms involved in NBT-induced cell death.

RESULTS

In this study, NBT effectively upregulated the expression of TOM20 and facilitated the translocation of BAX to mitochondria, which promoted the release of cytochrome c from mitochondria to the cytoplasm, leading to the activation of caspase-9 and caspase-3, and finally induced pyroptosis. Knocking out TOM20 by CRISPR-Cas9 significantly inhibited the expression of BAX and the downstream BAX/caspase-3/GSDME pathway, which attenuated NBT-induced pyroptosis. The elevated mitochondrial ROS level was observed after NBT treatment. Remarkably, the inhibition of ROS by N-acetylcysteine (NAC) effectively suppressed the activation of TOM20/BAX pathway. Moreover, in vivo experiments demonstrated that NBT exhibited potent antitumor effects in both KYSE450 and TOM20 knockout KYSE450-/- xenograft models. Notably, the attenuated antitumor effects and reduced cleavage of GSDME were observed in the TOM20 knockout model.

CONCLUSION

These findings reveal that NBT induces pyroptosis through ROS/TOM20/BAX/GSDME pathway, which highlight the therapeutic potential of targeting TOM20 and GSDME, providing promising prospects for the development of innovative and effective treatment approaches for esophageal cancer.

Redox signaling in cell fate: Beyond damage

This review explores the nuanced role of reactive oxygen species (ROS) in cell fate, challenging the traditional view that equates ROS with cellular damage. Through significant technological advancements in detecting localized redox states and identifying oxidized cysteines, a paradigm shift has emerged: from ROS as merely damaging agents to crucial players in redox signaling. We delve into the intricacies of redox mechanisms, which, although confined, exert profound influences on cellular physiological responses. Our analysis extends to both the positive and negative impacts of these mechanisms on cell death processes, including uncontrolled and programmed pathways. By unraveling these complex interactions, we argue against the oversimplified notion of a 'stress response', advocating for a more nuanced understanding of redox signaling. This review underscores the importance of localized redox states in determining cell fate, highlighting the sophistication and subtlety of ROS functions beyond mere damage.

Migraine and gasdermin D: a new perspective on the inflammatory basis of migraine

Migraine is a common and disabling primary headache disorder and inflammation is a proposed factor in the complex ethiology of the disease. Gasdermin D (GSDMD) is a membrane pore-forming protein acting through the caspase system. End result is cell death caused by leakage of intracellular components to extracellular space which also results in inflammation. Stemming from this knowledge, the potential role of GSDMD in migraine was investigated in this prospective study. This prospective study was conducted between September 2022 to April 2023. 47 patients with migraine were designated as the patient group, whereas 47 healthy volunteers were designated as the control group. Serum GSDMD levels of both groups were compared, with an additional comparison between migraine patients during symptom-free and attack periods. Migraine related characteristics of the patients were also included in the study. Median GSDMD levels of the patient and control group did not reveal a significant difference. Nausea, vomiting and severity of headache were found to be correlated with GSDMD levels in migraine patients. Patients with nausea revealed a higher GSDMD level compared to patients without nausea during both symptom-free and attack periods (p = 0.021 and p = 0.01, respectively). Nausea was correlated to higher GSDMD levels in the patient population during symptom-free period (p = 0.030). The severity of pain was positively correlated with GSDMD levels during the attack period (p < 0.001). Gasdermin family and GSDMD in particular are promising prospects for therapy in a wide spectrum of disorders. Gasdermin proteins are candidates to be the focus for future studies both related to pathogenesis and drug therapy in migraine and varying inflammatory-driven clinical pictures.

Correlation of gasdermin B staining patterns with prognosis, progression, and immune response in colorectal cancer

BACKGROUND

Pyroptosis is a type of programmed cell death mediated by the gasdermin family. Gasdermin B (GSDMB), as a member of gasdermin family, can promote the occurrence of cell pyroptosis. However, the correlations of the GSDMB expression in colorectal cancer with clinicopathological predictors, immune microenvironment, and prognosis are unclear.

METHODS

Specimens from 267 colorectal cancer cases were analyzed by immunohistochemistry to determine GSDMB expression, CD3+, CD4+, and CD8+ T lymphocytes, CD20+ B lymphocytes, CD68+ macrophages, and S100A8+ immune cells. GSDMB expression in cancer cells was scored in the membrane, cytoplasm, and nucleus respectively. GSDMB+ immune cell density was calculated. Univariate and multivariate survival analyses were performed. The association of GSDMB expression with other clinicopathological variables and immune cells were also analyzed. Double immunofluorescence was used to identify the nature of GSDMB+ immune cells. Cytotoxicity assays and sensitivity assays were performed to detect the sensitivity of cells to 5-fluorouracil.

RESULTS

Multivariate survival analysis showed that cytoplasmic GSDMB expression was an independent favorable prognostic indicator. Patients with positive cytoplasmic or nuclear GSDMB expression would benefit from 5-fluorouracil based chemotherapy. The assays in vitro showed that high GSDMB expression enhanced the sensitivity of colorectal cancer cells to 5-fluorouracil. Patients with positive membranous or nuclear GSDMB expression had more abundant S100A8+ immune cells in the tumor invasive front. Positive nuclear GSDMB expression indicated more CD68+ macrophages in the tumor microenvironment. Moreover, GSDMB+ immune cell density in the stroma was associated with a higher neutrophil percentage but a lower lymphocyte counts and monocyte percentage in peripheral blood. Furthermore, the results of double immunofluorescence showed that GSDMB co-expressed with CD68 or S100A8 in stroma cells.

CONCLUSION

The GSDMB staining patterns are linked to its role in cancer progression, the immune microenvironment, systemic inflammatory response, chemotherapeutic efficacy, and prognosis. Colorectal cancer cells with high GSDMB expression are more sensitive to 5-fluorouracil. However, GSDMB expression in immune cells has different effects on cancer progression from that in cancer cells.

Palmitic acid induces GSDMD-mediated pyroptosis in periodontal ligament cells via the NF-κB pathway

OBJECTIVE

Obesity can affect periodontal tissues and exacerbate periodontitis. Pyroptosis, a newly identified type of inflammatory cell death, is involved in the development of periodontal inflammation. The saturated fatty acid palmitic acid (PA) is elevated in obese patients. The effect of PA on pyroptosis in periodontal ligament cells (PDLCs) and its underlying mechanisms remain unknown.

MATERIALS AND METHODS

Human PDLCs were isolated from healthy individuals and cultured for experiments. The effects of PA on PDLC pyroptosis and the underlying mechanisms were examined by transmission electron microscopy, quantitative real-time PCR and western blotting.

RESULTS

The morphology of PDLCs in the PA group indicated pyroptotic characteristics, including swollen cells, plasma membrane rupture and changes in subcellular organelles. PA induced inflammatory responses in PDLCs, as indicated by an increase in IL-1β in the cell culture supernatant. Furthermore, we found that the pyroptosis-related proteins caspase-1, caspase-4 and GSDMD were involved in PA-induced cell death. GSDMD and caspase-4 inhibitors alleviated pyroptotic death of PDLCs. Moreover, PA promoted NF-κB P65 phosphorylation. A NF-κB inhibitor decreased IL-1β expression and partly rescued cell death induced by PA.

CONCLUSION

PA activated the NF-κB pathway and induced the inflammatory response in PDLCs. Caspase-4/GSDMD mediated PDLC pyroptosis induced by PA.

New insights into Gasdermin D pore formation

Gasdermin D (GSDMD) is a pore-forming protein that perforates the plasma membrane (PM) during pyroptosis, a pro-inflammatory form of cell death, to induce the unconventional secretion of inflammatory cytokines and, ultimately, cell lysis. GSDMD is activated by protease-mediated cleavage of its active N-terminal domain from the autoinhibitory C-terminal domain. Inflammatory caspase-1, -4/5 are the main activators of GSDMD via either the canonical or non-canonical pathways of inflammasome activation, but under certain stimuli, caspase-8 and other proteases can also activate GSDMD. Activated GSDMD can oligomerize and assemble into various nanostructures of different sizes and shapes that perforate cellular membranes, suggesting plasticity in pore formation. Although the exact mechanism of pore formation has not yet been deciphered, cysteine residues are emerging as crucial modulators of the oligomerization process. GSDMD pores and thus the outcome of pyroptosis can be modulated by various regulatory mechanisms. These include availability of activated GSDMD at the PM, control of the number of GSDMD pores by PM repair mechanisms, modulation of the lipid environment and post-translational modifications. Here, we review the latest findings on the mechanisms that induce GSDMD to form membrane pores and how they can be tightly regulated for cell content release and cell fate modulation.

Nanomedicine-induced cell pyroptosis to enhance antitumor immunotherapy

Immunotherapy is a therapeutic modality designed to elicit or augment an immune response against malignancies. Despite the immune system's ability to detect and eradicate neoplastic cells, certain neoplastic cells can elude immune surveillance and elimination through diverse mechanisms. Therefore, antitumor immunotherapy has emerged as a propitious strategy. Pyroptosis, a type of programmed cell death (PCD) regulated by Gasdermin (GSDM), is associated with cytomembrane rupture due to continuous cell expansion, which results in the release of cellular contents that can trigger robust inflammatory and immune responses. The field of nanomedicine has made promising progress, enabling the application of nanotechnology to enhance the effectiveness and specificity of cancer therapy by potentiating, enabling, or augmenting pyroptosis. In this review, we comprehensively examine the paradigms underlying antitumor immunity, particularly paradigms related to nanotherapeutics combined with pyroptosis; these treatments include chemotherapy (CT), hyperthermia therapy, photodynamic therapy (PDT), chemodynamic therapy (CDT), ion-interference therapy (IIT), biomimetic therapy, and combination therapy. Furthermore, we thoroughly discuss the coordinated mechanisms that regulate these paradigms. This review is expected to enhance the understanding of the interplay between pyroptosis and antitumor immunotherapy, broaden the utilization of diverse nanomaterials in pyroptosis-based antitumor immunotherapy, and facilitate advancements in clinical tumor therapy.

Gasdermin B (GSDMB) in psoriatic patients-a preliminary comprehensive study on human serum, urine and skin

Psoriasis is one of the most common skin diseases and a crucial issue to manage in contemporary dermatology. The search for the details of its pathogenesis, markers and treatment is continuously ongoing. Our aim was to investigate the role of gasdermin B (GSDMB) in psoriasis, the second protein from the gasdermin family, involved in cell death and proliferation. GSDMB serum and urinary concentrations have never been studied in psoriatics, neither tissue expression of GSDMB by immunohistochemistry. The study included 60 psoriatic patients and 30 volunteers without dermatoses as controls. The serum and urinary GSDMB were evaluated by ELISA. Tissue expression of GSDMB was analyzed by immunohistochemistry. The serum and absolute urine concentrations of GSDMB were significantly higher in psoriatic patients than controls without skin diseases (p = 0.0137, p = 0.039 respectively). Urinary GSDMB/creatinine concentration ratio was significantly lower in patients compared to controls (p = 0.0241). The expression of GSDMB in the dermis and epidermis was significantly more prevalent in psoriatic plaque compared to the non-lesional skin and healthy skin of controls (p = 0.0012, p = 0.017, respectively). Serum GSDMB correlated positively with the age of patients (R = 0.41; p = 0.001). Our study adds to the current state of knowledge about psoriasis concerning the potential involvement of GSDMB. Possibly it could be engaged in keratinocytes migration, which requires further research. Elevated serum GSDMB and decreased urinary GSDMB/creatinine concentration ratio could potentially be investigated as psoriasis biomarkers. GSDMB could be investigated in the future as a potential therapeutic target.

The gasdermin family: emerging therapeutic targets in diseases

The gasdermin (GSDM) family has garnered significant attention for its pivotal role in immunity and disease as a key player in pyroptosis. This recently characterized class of pore-forming effector proteins is pivotal in orchestrating processes such as membrane permeabilization, pyroptosis, and the follow-up inflammatory response, which are crucial self-defense mechanisms against irritants and infections. GSDMs have been implicated in a range of diseases including, but not limited to, sepsis, viral infections, and cancer, either through involvement in pyroptosis or independently of this process. The regulation of GSDM-mediated pyroptosis is gaining recognition as a promising therapeutic strategy for the treatment of various diseases. Current strategies for inhibiting GSDMD primarily involve binding to GSDMD, blocking GSDMD cleavage or inhibiting GSDMD-N-terminal (NT) oligomerization, albeit with some off-target effects. In this review, we delve into the cutting-edge understanding of the interplay between GSDMs and pyroptosis, elucidate the activation mechanisms of GSDMs, explore their associations with a range of diseases, and discuss recent advancements and potential strategies for developing GSDMD inhibitors.

Exploring the role of pyroptosis in the pathogenicity of heart disease

Cell death is an essential cellular mechanism that ensures quality control and whole-body homeostasis. Various modes of cell death have been studied and detailed. Unbalanced cell death can lead to uncontrolled cell proliferation (i.e., tumors) or excessive loss of cells (i.e., ischemia injury tissue loss). Thus, it is imperative for modes of cell death to be balanced and controlled. Here, we will focus on a recent mode of cell death called pyroptosis. While extensive studies have shown the role of this route of cell death in macrophages and monocytes, evidence for pyroptosis have expanded to encompass other pathologies, including cancer and cardiac diseases. Herein, we provide a brief review on pyroptosis and discuss current gaps in knowledge and scientific advances in cardiac pyroptosis in recent years. Lastly, we provide conclusions and prospective on the relevance to various cardiac diseases.

Evolutionary insights and functional diversity of gasdermin family proteins and homologs in microorganisms

The gasdermin protein family and its homologs in microorganisms have gained significant attention due to their roles in programmed cell death, immune defense, and microbial infection. This review summarizes the current research status of gasdermin proteins, their structural features, and functional roles in fungi, bacteria, and viruses. The review presents evolutionary parallels between mammalian and microbial defense systems, highlighting the conserved role of gasdermin proteins in regulating cell death processes and immunity. Additionally, the structural and functional characteristics of gasdermin homologs in microorganisms are summarized, shedding light on their potential as targets for therapeutic interventions. Future research directions in this field are also discussed to provide a roadmap for further investigation.

Therapeutic strategies targeting the NLRP3‑mediated inflammatory response and pyroptosis in cerebral ischemia/reperfusion injury (Review)

Ischemic stroke poses a major threat to human health. Therefore, the molecular mechanisms of cerebral ischemia/reperfusion injury (CIRI) need to be further clarified, and the associated treatment approaches require exploration. The NOD‑like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome serves an important role in causing CIRI, and its activation exacerbates the underlying injury. Activation of the NLRP3 inflammasome triggers the maturation and production of the inflammatory molecules IL‑1β and IL‑18, as well as gasdermin‑D‑mediated pyroptosis and CIRI damage. Thus, the NLRP3 inflammasome may be a viable target for the treatment of CIRI. In the present review, the mechanisms of the NLRP3 inflammasome in the intense inflammatory response and pyroptosis induced by CIRI are discussed, and the therapeutic strategies that target the NLRP3‑mediated inflammatory response and pyroptosis in CIRI are summarized. At present, certain drugs have already been studied, highlighting future therapeutic perspectives.

Role of pyroptosis in the pathogenesis of various neurological diseases

Pyroptosis, an inflammatory programmed cell death process, has recently garnered significant attention due to its pivotal role in various neurological diseases. This review delves into the intricate molecular signaling pathways governing pyroptosis, encompassing both caspase-1 dependent and caspase-1 independent routes, while emphasizing the critical role played by the inflammasome machinery in initiating cell death. Notably, we explore the Nucleotide-binding domain leucine-rich repeat (NLR) containing protein family, the Absent in melanoma 2-like receptor family, and the Pyrin receptor family as essential activators of pyroptosis. Additionally, we comprehensively examine the Gasdermin family, renowned for their role as executioner proteins in pyroptosis. Central to our review is the interplay between pyroptosis and various central nervous system (CNS) cell types, including astrocytes, microglia, neurons, and the blood-brain barrier (BBB). Pyroptosis emerges as a significant factor in the pathophysiology of each cell type, highlighting its far-reaching impact on neurological diseases. This review also thoroughly addresses the involvement of pyroptosis in specific neurological conditions, such as HIV infection, drug abuse-mediated pathologies, Alzheimer's disease, and Parkinson's disease. These discussions illuminate the intricate connections between pyroptosis, chronic inflammation, and cell death in the development of these disorders. We also conducted a comparative analysis, contrasting pyroptosis with other cell death mechanisms, thereby shedding light on their unique aspects. This approach helps clarify the distinct contributions of pyroptosis to neuroinflammatory processes. In conclusion, this review offers a comprehensive exploration of the role of pyroptosis in various neurological diseases, emphasizing its multifaceted molecular mechanisms within various CNS cell types. By elucidating the link between pyroptosis and chronic inflammation in the context of neurodegenerative disorders and infections, it provides valuable insights into potential therapeutic targets for mitigating these conditions.

The lipid basis of cell death and autophagy

ABBREVIATIONS

ACSL: acyl-CoA synthetase long chain family; DISC: death-inducing signaling complex; DAMPs: danger/damage-associated molecular patterns; Dtgn: dispersed trans-Golgi network; FAR1: fatty acyl-CoA reductase 1; GPX4: glutathione peroxidase 4; LPCAT3: lysophosphatidylcholine acyltransferase 3; LPS: lipopolysaccharide; MUFAs: monounsaturated fatty acids; MOMP: mitochondrial outer membrane permeabilization; MLKL, mixed lineage kinase domain like pseudokinase; oxPAPC: oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine; OxPCs: oxidized phosphatidylcholines; PUFAs: polyunsaturated fatty acids; POR: cytochrome p450 oxidoreductase; PUFAs: polyunsaturated fatty acids; RCD: regulated cell death; RIPK1: receptor interacting serine/threonine kinase 1; SPHK1: sphingosine kinase 1; SOAT1: sterol O-acyltransferase 1; SCP2: sterol carrier protein 2; SFAs: saturated fatty acids; SLC47A1: solute carrier family 47 member 1; SCD: stearoyl-CoA desaturase; VLCFA: very long chain fatty acids.

Pyroptosis Tuning in Intestinal Cryptosporidiosis via the Natural Histone Deacetylase Inhibitor Romidepsin

Cryptosporidium is an opportunistic protozoan, with many species of cross-human infectivity. It causes life-threatening diarrhoea in children and CD4-defective patients. Despite its limited efficacy, nitazoxanide remains the primary anti-cryptosporidial drug. Cryptosporidium infects the intestinal brush border (intracellular-extracytoplasmic) and down-regulates pyroptosis to prevent expulsion. Romidepsin is a natural histone deacetylase inhibitor that triggers pyroptosis. Romidepsin's effect on cryptosporidiosis was assessed in immunocompromised mice via gasdermin-D (GSDM-D) immunohistochemical expression, IFN-γ, IL-1β and IL-18 blood levels by ELISA, and via parasite scanning by modified Ziehl-Neelsen staining and scanning electron microscopy (SEM). Oocyst deformity and local cytokines were also assessed in ex vivo ileal explants. Following intraperitoneal injection of romidepsin, oocyst shedding significantly reduced at the 9th, 12th and 15th d.p.i. compared with infected-control and drug-control (nitazoxanide-treated) mice. H&E staining of intestinal sections from romidepsin-treated mice showed significantly low intestinal scoring with marked reduction in epithelial hyperplasia, villous blunting and cellular infiltrate. SEM revealed marked oocyst blebbing and paucity (in vivo and ex vivo) after romidepsin compared with nitazoxanide. Regarding pyroptosis, romidepsin triggered significantly higher intestinal GSDM-D expression in vivo, and higher serum/culture IFN-γ, IL-1β and IL-18 levels in romidepsin-treated mice than in the control groups. Collectively, in cryptosporidiosis, romidepsin succeeded in enhancing pyroptosis in the oocysts and infected epithelium, reducing infection and shifting the brush border towards normalisation.

Harnessing Pyroptosis for Cancer Immunotherapy

Cancer immunotherapy is a novel pillar of cancer treatment that harnesses the immune system to fight tumors and generally results in robust antitumor immunity. Although immunotherapy has achieved remarkable clinical success for some patients, many patients do not respond, underscoring the need to develop new strategies to promote antitumor immunity. Pyroptosis is an immunostimulatory type of regulated cell death that activates the innate immune system. A hallmark of pyroptosis is the release of intracellular contents such as cytokines, alarmins, and chemokines that can stimulate adaptive immune activation. Recent studies suggest that pyroptosis promotes antitumor immunity. Here, we review the mechanisms by which pyroptosis can be induced and highlight new strategies to induce pyroptosis in cancer cells for antitumor defense. We discuss how pyroptosis modulates the tumor microenvironment to stimulate adaptive immunity and promote antitumor immunity. We also suggest research areas to focus on for continued development of pyroptosis as an anticancer treatment. Pyroptosis-based anticancer therapies offer a promising new avenue for treating immunologically 'cold' tumors.

Chemical Hypoxia Induces Pyroptosis in Neuronal Cells by Caspase-Dependent Gasdermin Activation

Hypoxia-induced neuronal death is a major cause of neurodegenerative diseases. Pyroptosis is a type of inflammatory programmed cell death mediated by elevated intracellular levels of reactive oxygen species (ROS). Therefore, we hypothesized that hypoxia-induced ROS may trigger pyroptosis via caspase-dependent gasdermin (GSDM) activation in neuronal cells. To test this, we exposed SH-SY5Y neuronal cells to cobalt chloride (CoCl2) to trigger hypoxia and then evaluated the cellular and molecular responses to hypoxic conditions. Our data revealed that CoCl2 induced cell growth inhibition and the expression of hypoxia-inducible factor-1α in SH-SY5Y cells. Exposure to CoCl2 elicits excessive accumulation of cytosolic and mitochondrial ROS in SH-SY5Y cells. CoCl2-induced hypoxia not only activated the intrinsic (caspases-3, -7, and -9) apoptotic pathway but also induced caspase-3/GSDME-dependent and NLRP3/caspase-1/GSDMD-mediated pyroptosis in SH-SY5Y cells. Importantly, inhibition of caspase-3 and -1 using selective inhibitors ameliorated pyroptotic cell death and downregulated GSDM protein expression. Additionally, treatment with a ROS scavenger significantly suppressed caspase- and pyroptosis-related proteins in CoCl2-treated SH-SY5Y cells. Our findings indicate that hypoxia-mediated ROS production plays an important role in the activation of both apoptosis and pyroptosis in SH-SY5Y neuronal cells, thus providing a potential therapeutic strategy for hypoxia-related neurological diseases.

Nuclear and mitochondrial genetic variants associated with mitochondrial DNA copy number

Mitochondrial DNA copy number (mtDNA-CN) is a biomarker for mitochondrial dysfunction associated with several diseases. Previous genome-wide association studies (GWAS) have been performed to unravel underlying mechanisms of mtDNA-CN regulation. However, the identified gene regions explain only a small fraction of mtDNA-CN variability. Most of this data has been estimated from microarrays based on various pipelines. In the present study we aimed to (1) identify genetic loci for qPCR-measured mtDNA-CN from three studies (16,130 participants) using GWAS, (2) identify potential systematic differences between our qPCR derived mtDNA-CN measurements compared to the published microarray intensity-based estimates, and (3) disentangle the nuclear from mitochondrial regulation of the mtDNA-CN phenotype. We identified two genome-wide significant autosomal loci associated with qPCR-measured mtDNA-CN: at HBS1L (rs4895440, p = 3.39 × 10-13) and GSDMA (rs56030650, p = 4.85 × 10-08) genes. Moreover, 113/115 of the previously published SNPs identified by microarray-based analyses were significantly equivalent with our findings. In our study, the mitochondrial genome itself contributed only marginally to mtDNA-CN regulation as we only detected a single rare mitochondrial variant associated with mtDNA-CN. Furthermore, we incorporated mitochondrial haplogroups into our analyses to explore their potential impact on mtDNA-CN. However, our findings indicate that they do not exert any significant influence on our results.

Gasdermins: a dual role in pyroptosis and tumor immunity

The gasdermin (GSDM) protein family plays a pivotal role in pyroptosis, a process critical to the body's immune response, particularly in combatting bacterial infections, impeding tumor invasion, and contributing to the pathogenesis of various inflammatory diseases. These proteins are adept at activating inflammasome signaling pathways, recruiting immune effector cells, creating an inflammatory immune microenvironment, and initiating pyroptosis. This article serves as an introduction to the GSDM protein-mediated pyroptosis signaling pathways, providing an overview of GSDMs' involvement in tumor immunity. Additionally, we explore the potential applications of GSDMs in both innovative and established antitumor strategies.

CD19 occupancy with tafasitamab increases therapeutic index of CART19 cell therapy and diminishes severity of CRS

ABSTRACT

In the development of various strategies of anti-CD19 immunotherapy for the treatment of B-cell malignancies, it remains unclear whether CD19 monoclonal antibody therapy impairs subsequent CD19-targeted chimeric antigen receptor T-cell (CART19) therapy. We evaluated the potential interference between the CD19-targeting monoclonal antibody tafasitamab and CART19 treatment in preclinical models. Concomitant treatment with tafasitamab and CART19 showed major CD19 binding competition, which led to CART19 functional impairment. However, when CD19+ cell lines were pretreated with tafasitamab overnight and the unbound antibody was subsequently removed from the culture, CART19 function was not affected. In preclinical in vivo models, tafasitamab pretreatment demonstrated reduced incidence and severity of cytokine release syndrome and exhibited superior antitumor effects and overall survival compared with CART19 alone. This was associated with transient CD19 occupancy with tafasitamab, which in turn resulted in the inhibition of CART19 overactivation, leading to diminished CAR T apoptosis and pyroptosis of tumor cells.

Novel, pathogenic insertion variant of GSDME associates with autosomal dominant hearing loss in a large Chinese pedigree

Nonsyndromic hearing loss (NSHL) is a genetically diverse, highly heterogeneous condition characterised by deafness, and Gasdermin E (GSDME) variants have been identified as directly inducing autosomal dominant NSHL. While many NSHL cases associated with GSDME involve the skipping of exon 8, there is another, less understood pathogenic insertion variant specifically found in Chinese pedigrees that causes deafness, known as autosomal dominant 5 (DFNA5) hearing loss. In this study, we recruited a large Chinese pedigree, conducted whole-exome and Sanger sequencing to serve as a comprehensive clinical examination, and extracted genomic DNA samples for co-segregation analysis of the members. Conservation and expression analyses for GSDME were also conducted. Our clinical examinations revealed an autosomal dominant phenotype of hearing loss in the family. Genetic analysis identified a novel insertion variant in GSDME exon 8 (GSDME: NM_004403.3: c.1113_1114insGGGGTGCAGCTTACAGGGTGGGTGT: p. P372fs*36). This variant is segregated with the deafness phenotype of this pedigree. The GSDME gene was highly conserved in the different species we analysed, and its mRNA expression was ubiquitously low in different human tissues. In conclusion, we have successfully identified a novel pathogenic insertion variant of GSDME in a Chinese pedigree that causes deafness, shedding light on the genetic basis of hearing loss within this specific family. Our findings expand the spectrum of known variants associated with GSDME-related deafness and may further support both the underlying gain-of-function mechanism and functional associations of GSDME hearing loss variants.

The Role of Gasdermin-D-Mediated Pryoptosis in Organ Injury and Its Therapeutic Implications

Gasdermin-D (GSDMD) belongs to the Gasdermin family (GSDM), which are pore-forming effector proteins that facilitate inflammatory cell death, also known as pyroptosis. This type of programmed cell death is dependent on inflammatory caspase activation, which cleaves gasdermin-D (GSDMD) to form membrane pores and initiates the release of pro-inflammatory cytokines. Pyroptosis plays an important role in achieving immune regulation and homeostasis within various organ systems. The role of GSDMD in pyroptosis has been extensively studied in recent years. In this review, we summarize the role of GSDMD in cellular and organ injury mediated by pyroptosis. We will also provide an outlook on GSDMD therapeutic targets in various organ systems.

Pyroptosis in microbial infectious diseases

Pyroptosis is a gasdermins-mediated programmed cell death that plays an essential role in immune regulation, and its role in autoimmune disease and cancer has been studied extensively. Increasing evidence shows that various microbial infections can lead to pyroptosis, associated with the occurrence and development of microbial infectious diseases. This study reviews the recent advances in pyroptosis in microbial infection, including bacterial, viral, and fungal infections. We also explore potential therapeutic strategies for treating microbial infection-related diseases by targeting pyroptosis.

GSDMA at the crossroads between pyroptosis and tumor immune evasion in glioma

Pyroptosis, an inflammatory and programmed cell death process, has been controversial in its role in tumor immunity. However, as the first molecule in the gasdermin family, the mechanism of GSDMA in glioma growth is not well understood. We identified the differentially expressed gene GSDMA from Treg cells-related genes using the TCGA database. The biological functions of GSDMA and the relationship between GSDMA expression and tumor immune cell infiltration and cancer patient survival were investigated using open-source databases and platforms. Additionally, flow cytometry analysis was used to examine the effect of GSDMA on tumor immune cell infiltration. Our study showed that GSDMA expression played an important role in immune evasion in glioma. Patients with high GSDMA expression had a worse prognosis. In vivo studies demonstrated that GSDMA knockdown could enhance the infiltration level of CD8+ T cells. High GSDMA expression was also positively correlated with poor anti-PD-L1 treatment outcomes in GBM patients, suggesting that GSDMA may be a potential biomarker that should be considered in combination with anti-PD-L1 therapy for glioma patients. In conclusion, our study demonstrates that high GSDMA expression in gliomas is associated with immune-infiltrating cells CD8+ T cells and Treg cells, and indicates a worse prognosis in glioma. Therefore, GSDMA may serve as a therapeutic target for glioma progression and should be applied in immunotherapy for glioma patients.

CASP1 is a target for combination therapy in pancreatic cancer

Gemcitabine (GEM) is commonly used as the first-line chemotherapeutic agent for treating pancreatic cancer (PC) patients. However, drug resistance is a major hurdle in GEM-based chemotherapy for PC. Recent studies have shown that pyroptosis, a type of programmed death, plays a significant regulatory role in cancer development and therapy. In this study, we observed an increase in the expression of Caspase-1(CASP1)/Gasdermin-D (GSDMD) in PC and found that high expression of CASP1 and GSDMD was associated with poor overall survival (OS) and progression-free survival (PFS) of PC patients. Knockdown of either CASP1 or GSDMD resulted in the inhibition of cell viability and migration in PC cells. More importantly, the knockdown of CASP1 or GSDMD enhanced GEM-induced cell death in PC cells. Interestingly, subsequent investigations demonstrated that enzymatically active CASP1 promoted GEM-induced cell death in PC cells. The activation of CASP1 by the DPP8/DPP9 inhibitor (Val-boroPro, VbP) increased GEM-induced cell death by inducing pyroptosis. These findings suggest that inhibiting CASP1 to suppress its oncogenic effects or activating it to promote cell pyroptosis both enhance the sensitivity of PC cells to GEM therapy.

Redox regulation of the NLRP3-mediated inflammation and pyroptosis

The review considers modern data on the mechanisms of activation and redox regulation of the NLRP3 inflammasome and gasdermins, as well as the role of selenium in these processes. Activation of the inflammasome and pyroptosis represent an evolutionarily conserved mechanism of the defense against pathogens, described for various types of cells and tissues (macrophages and monocytes, microglial cells and astrocytes, podocytes and parenchymal cells of the kidneys, periodontal tissues, osteoclasts and osteoblasts, as well as cells of the digestive and urogenital systems, etc.). Depending on the characteristics of redox regulation, the participants of NLRP3 inflammation and pyroptosis can be subdivided into 2 groups. Members of the first group block the mitochondrial electron transport chain, promote the formation of reactive oxygen species and the development of oxidative stress. This group includes granzymes, the mitochondrial antiviral signaling protein MAVS, and others. The second group includes thioredoxin interacting protein (TXNIP), erythroid-derived nuclear factor-2 (NRF2), Kelch-like ECH-associated protein 1 (Keap1), ninjurin (Ninj1), scramblase (TMEM16), inflammasome regulatory protein kinase NLRP3 (NEK7), caspase-1, gasdermins GSDM B, D and others. They have redox-sensitive domains and/or cysteine residues subjected to redox regulation, glutathionylation/deglutathionylation or other types of regulation. Suppression of oxidative stress and redox regulation of participants in NLRP3 inflammation and pyroptosis depends on the activity of the antioxidant enzymes glutathione peroxidase (GPX) and thioredoxin reductase (TRXR), containing a selenocysteine residue Sec in the active site. The expression of GPX and TRXR is regulated by NRF2 and depends on the concentration of selenium in the blood. Selenium deficiency causes ineffective translation of the Sec UGA codon, translation termination, and, consequently, synthesis of inactive selenoproteins, which can cause various types of programmed cell death: apoptosis of nerve cells and sperm, necroptosis of erythrocyte precursors, pyroptosis of infected myeloid cells, ferroptosis of T- and B-lymphocytes, kidney and pancreatic cells. In addition, suboptimal selenium concentrations in the blood (0.86 μM or 68 μg/l or less) have a significant impact on expression of more than two hundred and fifty genes as compared to the optimal selenium concentration (1.43 μM or 113 μg/l). Based on the above, we propose to consider blood selenium concentrations as an important parameter of redox homeostasis in the cell. Suboptimal blood selenium concentrations (or selenium deficiency states) should be used for assessment of the risk of developing inflammatory processes.

Pyroptosis inhibiting nanobodies block Gasdermin D pore formation

Human Gasdermin D (GSDMD) is a key mediator of pyroptosis, a pro-inflammatory form of cell death occurring downstream of inflammasome activation as part of the innate immune defence. Upon cleavage by inflammatory caspases in the cytosol, the N-terminal domain of GSDMD forms pores in the plasma membrane resulting in cytokine release and eventually cell death. Targeting GSDMD is an attractive way to dampen inflammation. In this study, six GSDMD targeting nanobodies are characterized in terms of their binding affinity, stability, and effect on GSDMD pore formation. Three of the nanobodies inhibit GSDMD pore formation in a liposome leakage assay, although caspase cleavage was not perturbed. We determine the crystal structure of human GSDMD in complex with two nanobodies at 1.9 Å resolution, providing detailed insights into the GSDMD-nanobody interactions and epitope binding. The pore formation is sterically blocked by one of the nanobodies that binds to the oligomerization interface of the N-terminal domain in the multi-subunit pore assembly. Our biochemical and structural findings provide tools for studying inflammasome biology and build a framework for the design of GSDMD targeting drugs.

Pyroptosis in neurodegenerative diseases: from bench to bedside

The central nervous system regulates all aspects of physiology to some extent. Neurodegenerative diseases (NDDs) lead to the progressive loss and dysfunction of neurons, which are particularly evident in Alzheimer's disease, Parkinson's disease, and many other conditions. NDDs are multifactorial diseases with complex pathogeneses, and there has been a rapid increase in the prevalence of NDDs. However, none of these diseases can be cured, making the development of novel treatment strategies an urgent necessity. Numerous studies have indicated how pyroptosis induces inflammation and affects many aspects of NDD. Therefore, components related to pyroptosis are potential therapeutic candidates and are attracting increasing attention. Here, we review the role of pyroptosis in the pathogenesis of NDDs and potential treatment options. Additionally, several of the current drugs and relevant inhibitors are discussed. Through this article, we provide theoretical support for exploring new therapeutic targets and updating clinical treatment strategies for NDDs. Notably, pyroptosis, a recently widely studied mode of cell death, is still under-researched compared to other traditional forms of cell death. Moreover, the focus of research has been on the onset and progression of NDDs, and the lack of organ-specific target discovery and drug development is a common problem for many basic studies. This urgent problem requires scientists and companies worldwide to collaborate in order to develop more effective drugs against NDDs.

Gasdermins in sepsis

Sepsis is a hyper-heterogeneous syndrome in which the systemic inflammatory response persists throughout the course of the disease and the inflammatory and immune responses are dynamically altered at different pathogenic stages. Gasdermins (GSDMs) proteins are pore-forming executors in the membrane, subsequently mediating the release of pro-inflammatory mediators and inflammatory cell death. With the increasing research on GSDMs proteins and sepsis, it is believed that GSDMs protein are one of the most promising therapeutic targets in sepsis in the future. A more comprehensive and in-depth understanding of the functions of GSDMs proteins in sepsis is important to alleviate the multi-organ dysfunction and reduce sepsis-induced mortality. In this review, we focus on the function of GSDMs proteins, the molecular mechanism of GSDMs involved in sepsis, and the regulatory mechanism of GSDMs-mediated signaling pathways, aiming to provide novel ideas and therapeutic strategies for the diagnosis and treatment of sepsis.

Caspase-3/GSDME mediated pyroptosis: A potential pathway for sepsis

The inflammatory response is one of the host's mechanisms to combat pathogens. Normal and controlled inflammation can accelerate the clearance of pathogens. However, in sepsis, the host often exhibits an excessive inflammatory response to infection, leading to tissue and organ damage. Therefore, studying the mechanisms underlying the occurrence and development of sepsis is of significant importance. Pyroptosis is a form of programmed cell death (PCD) executed by the gasdermins (GSDMs) family, and its pro-inflammatory characteristics are considered a crucial component of the sepsis mechanism. Previous research on pyroptosis in sepsis has mainly focused on the caspase-1/4/5/11-GSDMD pathway, which has made significant progress. However, there is a lack of research on the roles of other GSDMs family members in sepsis. New research has revealed that the caspase-3/GSDME pathway can also mediate pyroptosis, playing important roles in cancer, other inflammatory diseases, and even some sepsis-related conditions. This discovery suggests the potential value of investigating caspase-3/GSDME in sepsis research. This review provides an overview of the role of the GSDMs family in infectious diseases, summarizes current research on the caspase-1/4/5/11-GSDMD pathway, describes the role of caspase-3 in sepsis, and discusses the research findings related to pyroptosis mediated by the caspase-3/GSDME pathway in cancer, inflammatory diseases, and sepsis-related conditions. The aim of this article is to propose the concept of caspase-3/GSDME as a potential target in sepsis research. Considering the role of this pathway in other diseases, including inflammatory conditions, and given the unique nature of sepsis as an inflammatory disease, the article suggests that this pathway may also play a role in sepsis. This hypothesis provides new insights and options for future sepsis research, although direct experiments are needed to validate this hypothesis.

Roles of pyroptosis in atherosclerosis pathogenesis

Pyroptosis is a pro-inflammatory type of regulated cell death (RCD) characterized by gasdermin protein-mediated membrane pore formation, cell swelling, and rapid lysis. Recent studies have suggested that pyroptosis is closely related to atherosclerosis (AS). Previous studies reported that pyroptosis involving endothelial cells (ECs), macrophages, and smooth muscle cells (SMCs) plays an important role in the formation and development of AS. Pyroptosis not only causes local inflammation but also amplifies the inflammatory response and it aggravates plaque instability, leading to plaque rupture and thrombosis, eventually resulting in acute cardiovascular events. In this review, we clarified some novel pathways and mechanics and presented some potential drugs.

GPX4 in cell death, autophagy, and disease

Selenoprotein GPX4 (glutathione peroxidase 4), originally known as PHGPX (phospholipid hydroperoxide glutathione peroxidase), is the main oxidoreductase in the use of glutathione as a reducing agent in scavenging lipid peroxidation products. There are three GPX4 isoforms: cytosolic (cGPX4), mitochondrial (mGPX4), and nuclear (nGPX4), with distinct spatiotemporal expression patterns during embryonic development and adult life. In addition to inducing the main phenotype of ferroptosis, the loss of GPX4 can in some cells trigger apoptosis, necroptosis, pyroptosis, or parthanatos, which mediates or accelerates developmental defects, tissue damage, and sterile inflammation. The interaction of GPX4 with the autophagic degradation pathway further modulates cell fate in response to oxidative stress. Impaired GPX4 function is implicated in tumorigenesis, neurodegeneration, infertility, inflammation, immune disorders, and ischemia-reperfusion injury. Additionally, the R152H mutation in GPX4 can promote the development of Sedaghatian-type spinal metaphyseal dysplasia, a rare and fatal disease in newborns. Here, we discuss the roles of classical GPX4 functions as well as emerging GPX4-regulated processes in cell death, autophagy, and disease.Abbreviations: AA: arachidonic acid; cGPX4: cytosolic GPX4; CMA: chaperone-mediated autophagy; DAMPs: danger/damage-associated molecular patterns; mGPX4: mitochondrial GPX4; nGPX4: nuclear GPX4; GSDMD-N: N-terminal fragment of GSDMD; I/R: ischemia-reperfusion; PLOOH: phospholipid hydroperoxide; PUFAs: polyunsaturated fatty acids; RCD: regulated cell death; ROS: reactive oxygen species; Se: selenium; SSMD: Sedaghatian-type spondylometaphyseal dysplasia; UPS: ubiquitin-proteasome system.

The gasdermins: a pore-forming protein family expressed in the epidermis

Gasdermins comprise a family of pore-forming proteins, which play critical roles in (auto)inflammatory diseases and cancer. They are expressed as self-inhibited precursor proteins consisting of an aminoterminal cytotoxic effector domain (NT-GSDM) and a carboxyterminal inhibitor domain (GSDM-CT) separated by an unstructured linker region. Proteolytic processing in the linker region liberates NT-GSDM, which translocates to membranes, forms oligomers, and induces membrane permeabilization, which can disturb the cellular equilibrium that can lead to cell death. Gasdermin activation and pore formation are associated with inflammation, particularly when induced by the inflammatory protease caspase-1 upon inflammasome activation. These gasdermin pores allow the release of the pro-inflammatory cytokines interleukin(IL)-1β and IL-18 and induce a lytic type of cell death, termed pyroptosis that supports inflammation, immunity, and tissue repair. However, even at the cellular level, the consequences of gasdermin activation are diverse and range from induction of programmed cell death - pyroptosis or apoptosis - to poorly characterized protective mechanisms. The specific effects of gasdermin activation can vary between species, cell types, the membrane that is being permeabilized (plasma membrane, mitochondrial membrane, etc.), and the overall biological state of the local tissue/cells. In epithelia, gasdermins seem to play crucial roles. Keratinocytes represent the main cell type of the epidermis, which is the outermost skin layer with an essential barrier function. Compared to other tissues, keratinocytes express all members of the gasdermin family, in part in a differentiation-specific manner. That raises questions regarding the specific roles of individual GSDM family members in the skin, the mechanisms and consequences of their activation, and the potential crosstalk between them. In this review, we summarize the current knowledge about gasdermins with a focus on keratinocytes and the skin and discuss the possible roles of the different family members in immunity and disease.

The Redox Protein High-Mobility Group Box 1 in Cell Death and Cancer

Significance: As a redox-sensitive protein, high-mobility group box 1 (HMGB1) is implicated in regulating stress responses to oxidative damage and cell death, which are closely related to the pathology of inflammatory diseases, including cancer. Recent Advances: HMGB1 is a nonhistone nuclear protein that acts as a deoxyribonucleic acid chaperone to control chromosomal structure and function. HMGB1 can also be released into the extracellular space and function as a damage-associated molecular pattern protein during cell death, including during apoptosis, necrosis, necroptosis, pyroptosis, ferroptosis, alkaliptosis, and cuproptosis. Once released, HMGB1 binds to membrane receptors to shape immune and metabolic responses. In addition to subcellular localization, the function and activity of HMGB1 also depend on its redox state and protein posttranslational modifications. Abnormal HMGB1 plays a dual role in tumorigenesis and anticancer therapy (e.g., chemotherapy, radiation therapy, and immunotherapy) depending on the tumor types and stages. Critical Issues: A comprehensive understanding of the role of HMGB1 in cellular redox homeostasis is important for deciphering normal cellular functions and pathological manifestations. In this review, we discuss compartmental-defined roles of HMGB1 in regulating cell death and cancer. Understanding these advances may help us develop potential HMGB1-targeting drugs or approaches to treat oxidative stress-related diseases or pathological conditions. Future Directions: Further studies are required to dissect the mechanism by which HMGB1 maintains redox homeostasis under different stress conditions. A multidisciplinary effort is also required to evaluate the potential applications of precisely targeting the HMGB1 pathway in human health and disease. Antioxid. Redox Signal. 39, 569-590.

Role of gasdermin family proteins in cancers (Review)

The gasdermin (GSDM) family comprises six proteins, including GSDMA‑GSDME and Pejvakin. Most of these proteins have a crucial role in inducing pyroptosis; in particular, GSDMD and GSDME are the most extensively studied proteins as the executioners of the pyroptosis process. Pyroptosis is a highly pro‑inflammatory form of programmed cell death and is closely associated with the incidence, development and prognosis of multiple cancer types. The present review focused on the current knowledge of the molecular mechanism of GSDM‑mediated pyroptosis, its intricate role in cancer and the potential therapeutic value of its anti‑tumor effects.

Microbial gasdermins: More than a billion years of pyroptotic-like cell death

In the recent past, the concept of immunity has been extended to eukaryotic and prokaryotic microorganisms, like fungi and bacteria. The latest findings have drawn remarkable evolutionary parallels between metazoan and microbial defense-related genes, unveiling a growing number of shared transkingdom components of immune systems. One such component is the gasdermin family of pore-forming proteins - executioners of a highly inflammatory immune cell death program in mammals, termed pyroptosis. Pyroptotic cell death limits the spread of intracellular pathogens by eliminating infected cells and coordinates the broader inflammatory response to infection. The microbial gasdermins have similarly been implicated in defense-related cell death reactions in fungi, bacteria and archaea. Moreover, the discovery of the molecular regulators of gasdermin cytotoxicity in fungi and bacteria, has established additional evolutionary links to mammalian pyroptotic pathways. Here, we focus on the gasdermin proteins in microorganisms and their role in organismal defense and provide perspective on this remarkable case study in comparative immunology.

Pyroptosis and the cellular consequences of gasdermin pores

The family of gasdermin proteins plays a key role in the host response against external and internal pathogenic signals by mediating the form of inflammatory regulated cell death known as pyroptosis. One of the most well-studied gasdermins within innate immunity is gasdermin D, which is cleaved, oligomerizes, and forms plasma membrane pores. Gasdermin D pores lead to a number of downstream cellular consequences including plasma membrane rupture, or cell lysis. In this review, we describe mechanisms of activation for each of the gasdermins, their cell type specificity and some disease associations. We then discuss downstream consequences of gasdermin pore formation, including cellular mechanisms of membrane repair. Finally, we present some important next steps to better understand pyroptosis and the cellular consequences of gasdermin pore formation.

Role of NLRP3 inflammasome-mediated neuronal pyroptosis and neuroinflammation in neurodegenerative diseases

BACKGROUND

Neurodegenerative diseases are a common group of neurological disorders characterized by progressive loss of neuronal structure and function leading to cognitive impairment. Recent studies have shown that neuronal pyroptosis mediated by the NLRP3 inflammasome plays a crucial role in the pathogenesis of neurodegenerative diseases.

OBJECTIVE AND METHOD

The NLRP3 inflammasome is a multiprotein complex that, when activated within cells, triggers an inflammatory response, ultimately leading to pyroptotic cell death of neurons. Pyroptosis is a typical pro-inflammatory programmed cell death process occurring downstream of NLRP3 inflammasome activation, characterized by the formation of pores on the cell membrane by the GSDMD protein, leading to cell lysis and the release of inflammatory factors. It has been found that NLRP3 inflammasome-mediated neuronal pyroptosis is closely associated with the development of various neurodegenerative diseases, such as Alzheimer's disease, traumatic brain injury, and Parkinson's disease. Therefore, inhibiting NLRP3 inflammasome activation and attenuating neuronal pyroptosis could potentially serve as novel strategies for the treatment of neurodegenerative diseases.

RESULTS

The aim of this review is to explore the role of NLRP3 activation-mediated neuronal pyroptosis and neuroinflammation in neurodegenerative diseases. Firstly, we extensively discuss the relationship between NLRP3 inflammasome-mediated neuronal pyroptosis and neuroinflammation in various neurodegenerative diseases. Subsequently, we further explore the mechanisms driving NLRP3 activation and assembly, as well as the post-translational modifications regulating NLRP3 inflammasome activation.

CONCLUSION

Understanding these mechanisms will contribute to a deeper understanding of the link between neuronal pyroptosis and neurodegenerative diseases, and hold significant implications for the treatment and prevention of neurodegenerative diseases.

Gasdermin E (GSDME)-A New Potential Marker of Psoriasis and Its Metabolic Complications: The First Combined Study on Human Serum, Urine and Tissue

Psoriasis is a frequent and incurable skin disease whose pathogenesis is still not fully understood. It is characterized by immune disturbances leading to hyperproliferation and improper differentiation of keratinocytes. Gasdermin E (GSDME) is a protein from the gasdermin family involved in the processes of inflammation and cell death based on apoptosis, necroptosis and pyroptosis. It has never been studied in psoriatics' sera or urine before. Our study enrolled 60 patients with psoriasis and 30 volunteers without dermatoses as controls. Serum and urinary GSDME concentrations were examined by ELISA and tissue expression of GSDME by immunohistochemistry. Serum GSDME concentration was significantly higher in patients than controls (p < 0.05). There were no differences in urinary GSDME concentrations between patients and controls. GSDME expression was significantly higher in the psoriatic plaque than non-lesional patients' skin and compared to controls (both p < 0.001). There was no correlation between serum GSDME or its lesional expression and psoriasis severity, age or disease duration. GSDME serum concentration was significantly negatively correlated with BMI, triglycerides and glucose concentrations. The obtained results suggest the engagement of GSDME in psoriasis pathogenesis. It could potentially become a new non-invasive psoriasis marker. Considering its pro-apoptotic influence, GSDME could be compensatively elevated to direct cells towards apoptosis, whereas under other circumstances, it may lead to pyroptosis and sustain inflammation. GSDME may exert a protective influence on the metabolic complications in psoriasis which requires further studies.

Gasdermin D (GSDMD) Is Upregulated in Psoriatic Skin-A New Potential Link in the Pathogenesis of Psoriasis

Psoriasis is an important issue in daily dermatological practice. Not only is it an aesthetic defect but it is also a matter of decreased life quality and economic burden. However frequent, the pathogenesis of psoriasis remains uncertain despite numerous investigations. Gasdermins are a family of six proteins. Gasdermin D (GSDMD) is the best-studied from this group and is involved in the processes of inflammation, proliferation, and death of cells, especially pyroptosis. GSDMD has never been studied in psoriatic sera or urine before. Our study involved 60 patients with psoriasis and 30 volunteers without dermatoses as controls. Serum and urinary GSDMD concentrations were examined by ELISA. The tissue expression of GSDMD was assessed by immunohistochemistry. The serum-GSDMD concentration was insignificantly higher in the patients than controls. There were no differences in the urinary-GSDMD concentrations between the patients and controls. Strong tissue expression of GSDMD was significantly more prevalent in psoriatic plaque than in the non-lesional skin and healthy skin of the controls. There was no correlation between the serum-GSDMD concentrations and the psoriasis severity in PASI, age, or disease duration. Taking into consideration the documented role of gasdermins in cell proliferation and death, the increased expression of GSDMD in psoriatic skin may demonstrate the potential involvement of this protein in psoriasis pathogenesis. Neither serum, nor urinary GSDMD can be currently considered a psoriasis biomarker; however, future studies may change this perspective.

Copper metabolism in cell death and autophagy

Copper is an essential trace element in biological systems, maintaining the activity of enzymes and the function of transcription factors. However, at high concentrations, copper ions show increased toxicity by inducing regulated cell death, such as apoptosis, paraptosis, pyroptosis, ferroptosis, and cuproptosis. Furthermore, copper ions can trigger macroautophagy/autophagy, a lysosome-dependent degradation pathway that plays a dual role in regulating the survival or death fate of cells under various stress conditions. Pathologically, impaired copper metabolism due to environmental or genetic causes is implicated in a variety of human diseases, such as rare Wilson disease and common cancers. Therapeutically, copper-based compounds are potential chemotherapeutic agents that can be used alone or in combination with other drugs or approaches to treat cancer. Here, we review the progress made in understanding copper metabolic processes and their impact on the regulation of cell death and autophagy. This knowledge may help in the design of future clinical tools to improve cancer diagnosis and treatment.Abbreviations: ACSL4, acyl-CoA synthetase long chain family member 4; AIFM1/AIF, apoptosis inducing factor mitochondria associated 1; AIFM2, apoptosis inducing factor mitochondria associated 2; ALDH, aldehyde dehydrogenase; ALOX, arachidonate lipoxygenase; AMPK, AMP-activated protein kinase; APAF1, apoptotic peptidase activating factor 1; ATF4, activating transcription factor 4; ATG, autophagy related; ATG13, autophagy related 13; ATG5, autophagy related 5; ATOX1, antioxidant 1 copper chaperone; ATP, adenosine triphosphate; ATP7A, ATPase copper transporting alpha; ATP7B, ATPase copper transporting beta; BAK1, BCL2 antagonist/killer 1; BAX, BCL2 associated X apoptosis regulator; BBC3/PUMA, BCL2 binding component 3; BCS, bathocuproinedisulfonic acid; BECN1, beclin 1; BID, BH3 interacting domain death agonist; BRCA1, BRCA1 DNA repair associated; BSO, buthionine sulphoximine; CASP1, caspase 1; CASP3, caspase 3; CASP4/CASP11, caspase 4; CASP5, caspase 5; CASP8, caspase 8; CASP9, caspase 9; CCS, copper chaperone for superoxide dismutase; CD274/PD-L1, CD274 molecule; CDH2, cadherin 2; CDKN1A/p21, cyclin dependent kinase inhibitor 1A; CDKN1B/p27, cyclin-dependent kinase inhibitor 1B; COMMD10, COMM domain containing 10; CoQ10, coenzyme Q 10; CoQ10H2, reduced coenzyme Q 10; COX11, cytochrome c oxidase copper chaperone COX11; COX17, cytochrome c oxidase copper chaperone COX17; CP, ceruloplasmin; CYCS, cytochrome c, somatic; DBH, dopamine beta-hydroxylase; DDIT3/CHOP, DNA damage inducible transcript 3; DLAT, dihydrolipoamide S-acetyltransferase; DTC, diethyldithiocarbamate; EIF2A, eukaryotic translation initiation factor 2A; EIF2AK3/PERK, eukaryotic translation initiation factor 2 alpha kinase 3; ER, endoplasmic reticulum; ESCRT-III, endosomal sorting complex required for transport-III; ETC, electron transport chain; FABP3, fatty acid binding protein 3; FABP7, fatty acid binding protein 7; FADD, Fas associated via death domain; FAS, Fas cell surface death receptor; FASL, Fas ligand; FDX1, ferredoxin 1; GNAQ/11, G protein subunit alpha q/11; GPX4, glutathione peroxidase 4; GSDMD, gasdermin D; GSH, glutathione; HDAC, histone deacetylase; HIF1, hypoxia inducible factor 1; HIF1A, hypoxia inducible factor 1 subunit alpha; HMGB1, high mobility group box 1; IL1B, interleukin 1 beta; IL17, interleukin 17; KRAS, KRAS proto-oncogene, GTPase; LOX, lysyl oxidase; LPCAT3, lysophosphatidylcholine acyltransferase 3; MAP1LC3, microtubule associated protein 1 light chain 3; MAP2K1, mitogen-activated protein kinase kinase 1; MAP2K2, mitogen-activated protein kinase kinase 2; MAPK, mitogen-activated protein kinases; MAPK14/p38, mitogen-activated protein kinase 14; MEMO1, mediator of cell motility 1; MT-CO1/COX1, mitochondrially encoded cytochrome c oxidase I; MT-CO2/COX2, mitochondrially encoded cytochrome c oxidase II; MTOR, mechanistic target of rapamycin kinase; MTs, metallothioneins; NAC, N-acetylcysteine; NFKB/NF-Κb, nuclear factor kappa B; NLRP3, NLR family pyrin domain containing 3; NPLOC4/NPL4, NPL4 homolog ubiquitin recognition factor; PDE3B, phosphodiesterase 3B; PDK1, phosphoinositide dependent protein kinase 1; PHD, prolyl-4-hydroxylase domain; PIK3C3/VPS34, phosphatidylinositol 3-kinase catalytic subunit type 3; PMAIP1/NOXA, phorbol-12-myristate-13-acetate-induced protein 1; POR, cytochrome P450 oxidoreductase; PUFA-PL, PUFA of phospholipids; PUFAs, polyunsaturated fatty acids; ROS, reactive oxygen species; SCO1, synthesis of cytochrome C oxidase 1; SCO2, synthesis of cytochrome C oxidase 2; SLC7A11, solute carrier family 7 member 11; SLC11A2/DMT1, solute carrier family 11 member 2; SLC31A1/CTR1, solute carrier family 31 member 1; SLC47A1, solute carrier family 47 member 1; SOD1, superoxide dismutase; SP1, Sp1 transcription factor; SQSTM1/p62, sequestosome 1; STEAP4, STEAP4 metalloreductase; TAX1BP1, Tax1 binding protein 1; TEPA, tetraethylenepentamine; TFEB, transcription factor EB; TM, tetrathiomolybdate; TP53/p53, tumor protein p53; TXNRD1, thioredoxin reductase 1; UCHL5, ubiquitin C-terminal hydrolase L5; ULK1, Unc-51 like autophagy activating kinase 1; ULK1, unc-51 like autophagy activating kinase 1; ULK2, unc-51 like autophagy activating kinase 2; USP14, ubiquitin specific peptidase 14; VEGF, vascular endothelial gro wth factor; XIAP, X-linked inhibitor of apoptosis.

Pyroptosis: A road to next-generation cancer immunotherapy

The goal of cancer immunotherapy is to clear tumor cells by activating antitumor immunity, especially by mobilizing tumor-reactive CD8+T cells. Pyroptosis, programmed lytic cell death mediated by gasdermin (GSDM), results in the release of cellular antigens, damage-associated molecular patterns (DAMPs) and cytokines. Therefore, pyroptotic tumor cell-derived tumor antigens and DAMPs not only reverse immunosuppression of the tumor microenvironment (TME) but also enhance tumor antigen presentation by dendritic cells, leading to robust antitumor immunity. Exploring nanoparticles and other approaches to spatiotemporally control tumor pyroptosis by regulating gasdermin expression and activation is promising for next-generation immunotherapy.

Role of Gasdermin E in the Biogenesis of Apoptotic Cell-Derived Exosomes

The gasdermins are a family of pore-forming proteins that has recently been suggested to play a central role in pyroptosis. In this study, we describe the novel roles of gasdermins in the biogenesis of apoptotic cell-derived exosomes. In apoptotic human HeLa and HEK293 cells, GSDMA, GSDMC, GSDMD, and GSDME increased the release of apoptotic exosomes. GSDMB and DFNB59, in contrast, negatively affected the release of apoptotic exosomes. GSDME at its full-length and cleaved forms was localized in the exosomes and exosomal membrane. Full-length and cleaved forms of GSDME are suggested to increase Ca2+ influx to the cytosol through endosomal pores and thus increase the biogenesis of apoptotic exosomes. In addition, the GSDME-mediated biogenesis of apoptotic exosomes depended on the ESCRT-III complex and endosomal recruitment of Ca2+-dependent proteins, that is, annexins A2 and A7, the PEF domain family proteins sorcin and grancalcin, and the Bro1 domain protein HD-PTP. Therefore, we propose that the biogenesis of apoptotic exosomes begins when gasdermin-mediated endosomal pores increase cytosolic Ca2+, continues through the recruitment of annexin-sorcin/grancalcin-HD-PTP, and is completed when the ESCRT-III complex synthesizes intraluminal vesicles in the multivesicular bodies of dying cells. Finally, we found that GSDME-bearing tumors released apoptotic exosomes to induce inflammatory responses in the in vivo mouse 4T1 orthotropic model of BALB/c breast cancer. The data indicate that the switch from apoptosis to pyroptosis could drive the transfer of mass signals to nearby or distant living cells and tissues by way of extracellular vesicles, and that gasdermins play critical roles in that process.

The gasdermin protein family: emerging roles in gastrointestinal health and disease

Since the identification and characterization of gasdermin (GSDM) D as the main effector of inflammatory regulated cell death (or pyroptosis), literature on the GSDM family of pore-forming proteins is rapidly expanding, revealing novel mechanisms regulating their expression and functions that go beyond pyroptosis. Indeed, a growing body of evidence corroborates the importance of GSDMs within the gastrointestinal system, underscoring their critical contributions to the pathophysiology of gastrointestinal cancers, enteric infections and gut mucosal inflammation, such as inflammatory bowel disease. However, with this increase in knowledge, several important and controversial issues have arisen regarding basic GSDM biology and its role(s) during health and disease states. These include critical questions centred around GSDM-dependent lytic versus non-lytic functions, the biological activities of cleaved versus full-length proteins, the differential roles of GSDM-expressing mucosal immune versus epithelial cells, and whether GSDMs promote pathogenic or protective effects during specific disease settings. This Review provides a comprehensive summary and interpretation of the current literature on GSDM biology, specifically focusing on the gastrointestinal tract, highlighting the main controversial issues and their clinical implications, and addressing future areas of research to unravel the specific role(s) of this intriguing, yet enigmatic, family of proteins.

The Pyroptotic and Nonpyroptotic Roles of Gasdermins in Modulating Cancer Progression and Their Perspectives on Cancer Therapeutics

Gasdermins (GSDMs) are a protein family encoded by six paralogous genes in humans, including GSDMA, GSDMB, GSDMC, GSDMD, GSDME (also known as DFNA5), and DFNB59 (also known as pejvakin). Structurally, members of the GSDM family possess a C-terminus (an autoinhibitory domain) and a positively charged N-terminus (a pore-forming domain) linked with divergent peptide linkers. Recently, GSDMs have been identified as key executors of pyroptosis (an immunogenic programmed cell death) due to their pore-forming activities on the plasma membrane when proteolytically cleaved by caspases or serine proteases. Accumulating studies suggest that chemoresistance is attributed to dysregulation of apoptotic machinery and that inducing pyroptosis to bypass aberrant apoptosis can potently resensitize apoptosis-resistant cancer to chemotherapeutics. Pyroptosis is initiated by pore formation and culminates with plasma membrane rupture; these processes enable the release of proinflammatory cytokines (e.g., IL-1β and IL-18) and damage-associated molecular patterns, which further modulate antitumor immunity within the tumor microenvironment. Although pyroptosis is considered a promising strategy to boost antitumor effects, it is also reported to cause unwanted tissue damage (e.g., gut damage and nephrotoxicity). Intriguingly, mounting evidence has uncovered nonpyroptotic roles of GSDMs in tumorigenesis, such as proliferation, invasion, metastasis, and drug resistance. Thus, this provides a rationale for GSDMs as potential therapeutic targets. Taken together, we shed unbiased light on the pyroptosis-dependent roles of GSDMs in cancer progression and highlighted how GSDMs modulate tumorigenesis in a pyroptosis-independent manner. It is evident that targeting GSDMs seems profound in cancer management; however, several problems require further investigation to target GSDMs from bench to bedside, which is elucidated in the discussion section.

The pyroptotic role of Caspase-3/GSDME signalling pathway among various cancer: A Review

Cytotoxic drugs have long been recognised to kill cancer cells through apoptosis. According to a current study, pyroptosis inhibits cell proliferation and shrinks tumors. Pyroptosis and apoptosis are caspase-dependent programmed cell death (PCD) processes. Inflammasomes activate caspase-1 and latent cytokines, including IL-1β and IL-18, to cleave gasdermin E (GSDME) and induce pyroptosis. Gasdermin proteins activate caspase-3 to induce pyroptosis, which is associated with tumour genesis, development, and therapy response. These proteins may serve as therapeutic biomarkers for cancer detection, and their antagonists may be a new target. Caspase-3, a crucial protein in both pyroptosis and apoptosis, governs tumour cytotoxicity when activated, and GSDME expression modulates this. Once active caspase-3 cleaves GSDME, its N-terminal domain punches holes in the cell membrane, causing it to expand, burst, and die. To understand the cellular and molecular mechanisms of PCD mediated by caspase-3 and GSDME, we focused on pyroptosis. Hence, caspase-3 and GSDME may be promising targets for cancer treatment.

Recent Organic Photosensitizer Designs for Evoking Proinflammatory Regulated Cell Death in Antitumor Immunotherapy

In the past decades, immunotherapy has achieved a series of clinical successes in the field of cancer. However, existing therapeutic options usually show a low immune response to solid tumors caused by immunosuppressive "cold" tumor microenvironment (TME). Several types of proinflammatory regulated cell death (RCD), mainly including ferroptosis and pyroptosis, have been studied recently, which can provide proinflammatory signals and immunogenicity necessary for remodeling TME and activating an antitumor immune response. A variety of chemotherapeutic drugs are proven to be effective in the proinflammatory RCD induction of tumor cells, but several adverse effects and intrinsic drug resistance usually occur in the therapeutic process, greatly hindering their further clinical application. The emerging organic photosensitizer (PS)-based materials open new possibilities to effectively activate proinflammatory RCD through precise spatiotemporal regulation of intracellular reactive oxygen species-associated signaling pathways, which can overcome many challenges encountered in current proinflammatory RCD-mediated immunotherapy. In this review, the recent design strategies of PS probes are detailly summarized and their potential advantages for tumor-specific proinflammatory RCD induction are discussed. Moreover, the representative examples in cancer immunotherapy are highlighted and future perspectives in this emerging field are proposed.