Caspase-8 is the molecular switch for apoptosis, necroptosis and pyroptosis

Redox cell signalling triggered by black carbon and/or radiofrequency electromagnetic fields: Influence on cell death

The capacity of environmental pollutants to generate oxidative stress is known to affect the development and progression of chronic diseases. This scientific review identifies previously published experimental studies using preclinical models of exposure to environmental stress agents, such as black carbon and/or RF-EMF, which produce cellular oxidative damage and can lead to different types of cell death. We summarize in vivo and in vitro studies, which are grouped according to the mechanisms and pathways of redox activation triggered by exposure to BC and/or EMF and leading to apoptosis, necrosis, necroptosis, pyroptosis, autophagy, ferroptosis and cuproptosis. The possible mechanisms are considered in relation to the organ, cell type and cellular-subcellular interaction with the oxidative toxicity caused by BC and/or EMF at the molecular level. The actions of these environmental pollutants, which affect everyday life, are considered separately and together in experimental preclinical models. However, for overall interpretation of the data, toxicological studies must first be conducted in humans, to enable possible risks to human health to be established in relation to the progression of chronic diseases. Further actions should take pollution levels into account, focusing on the most vulnerable populations and future generations.

Caspase-8 in inflammatory diseases: a potential therapeutic target

Caspase-8, a renowned cysteine-aspartic protease within its enzyme family, initially garnered attention for its regulatory role in extrinsic apoptosis. With advancing research, a growing body of evidence has substantiated its involvement in other cell death processes, such as pyroptosis and necroptosis, as well as its modulatory effects on inflammasomes and proinflammatory cytokines. PANoptosis, an emerging concept of cell death, encompasses pyroptosis, apoptosis, and necroptosis, providing insight into the often overlapping cellular mortality observed during disease progression. The activation or deficiency of caspase-8 enzymatic activity is closely linked to PANoptosis, positioning caspase-8 as a key regulator of cell survival or death across various physiological and pathological processes. Aberrant expression of caspase-8 is closely associated with the development and progression of a range of inflammatory diseases, including immune system disorders, neurodegenerative diseases (NDDs), sepsis, and cancer. This paper delves into the regulatory role and impact of caspase-8 in these conditions, aiming to elucidate potential therapeutic strategies for the future intervention.

Red-Light Triggered H-Abstraction Photoinitiators for the Efficient Oxygen-Independent Therapy of Hypoxic Tumors

The clinical application of photodynamic therapy (PDT) is limited by oxygen-dependence and side effects caused by photosensitizer residues. Photoinitiators based on the H-abstraction reaction can address these challenges because they can generate alkyl radical-killing cells independently of oxygen and undergo rapid bleaching following H-abstraction. Nonetheless, the development of photoinitiators for PDT has been impeded by the absence of effective design strategies. Herein, we have developed aryl-ketone substituted cyanine (ACy-R), the first red-light triggered H-abstraction photoinitiators for hypoxic cancer therapy. These ACy-R molecules inherited the near-infrared absorption of cyanine dye, and aryl-ketone modification imparted H-abstraction capability. Experimental and quantum calculations revealed that modifying the electron-withdrawing groups of the aryl (e.g., ACy-5F) improved the contribution of the O atom to the photon excitation process promoting intersystem crossing and H-abstraction ability. Particularly, ACy-5F rapidly penetrated cells and enriched in the endoplasmic reticulum. Even under severe hypoxia, ACy-5F initiated red-light induced H-abstraction with intracellular biomolecules, inducing necroptosis and ferroptosis. Moreover, ACy-5F was degraded after H-abstraction, thus avoiding the side effects of long-term phototoxicity after therapy. This study not only provides a crucial molecular tool for hypoxic tumors therapy, but also presents a promising strategy for the development of multifunctional photosensitizers and photoinitiators.

Genetic association and drug target exploration of inflammation-related proteins with risk of major depressive disorder

BACKGROUND

In numerous observational studies, circulating inflammation-related proteins have been linked with major depressive disorder (MDD), yet the precise causal direction of this relationship remains unclear. This study aims to investigate the potential causal link between inflammation-related proteins and the risk of developing MDD.

METHODS

We utilized summary data from a genome-wide association study (GWAS) of 91 circulating inflammation-associated proteins in 14,824 individuals of European descent. Additionally, we incorporated findings from a substantial GWAS on MDD, which included 294,322 cases and 741,438 controls. Our analysis employed a two-sample bidirectional Mendelian randomization (MR) approach, with inverse variance weighting (IVW) as the primary method. We augmented this with two supplementary techniques (MR-Egger and weighted median approaches) to detect and address potential pleiotropy. Furthermore, to identify and evaluate possible drug targets, we conducted a thorough search within the Drug-Gene Interaction Database (DGIdb).

RESULTS

Analysis using MR unveiled significant and causative associations between genetically determined CASP-8 (odds ratio (OR): 0.97), CD40 (OR: 0.96), IL-18 (OR: 0.98), SLAMF1 (OR: 0.97), and uPA (OR: 0.98) with MDD. Conversely, reverse MR analysis indicated causal associations between MDD and CCL19 (OR: 1.15), HGF (OR: 1.15), IL-8 (OR: 1.10), IL-18 (OR: 1.11), IL20RA (OR: 1.12), TGFA (OR: 1.12) and TNFSF14 (OR: 1.16). Notably, a significant bidirectional causal link was observed between IL-18 and MDD. Gene-drug analysis identified CD40, HGF, IL-8, IL-18, SLAMF1, and TGFA as potential therapeutic targets.

CONCLUSIONS

We've pinpointed causal links between inflammation-related proteins and MDD, offering compelling and innovative evidence to enhance our understanding of the inflammatory mechanisms involved in MDD and to investigate potential targets for anti-MDD medications.

PARP inhibitors enhance antitumor immune responses by triggering pyroptosis via TNF-caspase 8-GSDMD/E axis in ovarian cancer

BACKGROUND

In addition to their established action of synthetic lethality in tumor cells, poly(ADP-ribose) polymerase inhibitors (PARPis) also orchestrate tumor immune microenvironment (TIME) that contributes to suppressing tumor growth. However, it remains not fully understood whether and how PARPis trigger tumor-targeting immune responses.

METHODS

To decode the immune responses reshaped by PARPis, we conducted T-cell receptor (TCR) sequencing and immunohistochemical (IHC) analyses of paired clinical specimens before and after niraparib monotherapy obtained from a prospective study, as well as ID8 mouse ovarian tumors. To validate the induction of immunogenic cell death (ICD) by PARPis, we performed immunofluorescence/IHC staining with homologous recombination deficiency tumor cells and patient-derived xenograft tumor tissues, respectively. To substantiate that PARPis elicited tumor cell pyroptosis, we undertook comprehensive assessments of the cellular morphological features, cleavage of gasdermin (GSDM) proteins, and activation of TNF-caspase signaling pathways through genetic downregulation/depletion and selective inhibition. We also evaluated the critical role of pyroptosis in tumor suppression and immune activation following niraparib treatment using a syngeneic mouse model with implanting CRISPR/Cas9 edited Gsdme-/ - ID8 tumor cells into C57BL/6 mice.

RESULTS

Our findings revealed that PARPis augmented the proportion of neoantigen-recognized TCR clones and TCR clonal expansion, and induced an inflamed TIME characterized by increased infiltration of both innate and adaptive immune cells. This PARPis-strengthened immune response was associated with the induction of ICD, specifically identified as pyroptosis, which possessed distinctive morphological features and GSDMD/E cleavage. It was validated that the cleavage of GSDMD/E was due to elevated caspase 8 activity downstream of the TNFR1, rather than FAS and TRAIL-R. On PARP inhibition, the NF-κB signaling pathway was activated, leading to increased secretion of TNF-α and subsequent initiation of the TNFR1-caspase 8 cascade. Impeding pyroptosis through the depletion of Gsdme significantly compromised the tumor-suppressing effects of PARP inhibition and undermined the anti-immune response in the syngeneic ID8 mouse model.

CONCLUSIONS

PARPis induce a specific type of ICD called pyroptosis via TNF-caspase 8-GSDMD/E axis, resulting in an inflamed TIME and augmentation of tumor-targeting immune responses. These findings deepen our understanding of PARPis activities and point toward a promising avenue for synergizing PARPis with immunotherapeutic interventions.

TRIAL REGISTRATION NUMBER

NCT04507841.

Exploring the therapeutic mechanisms of resveratrol for treating arecoline-induced malignant transformation in oral epithelial cells: insights into hub targets

BACKGROUND

Betel nut chewing is a significant risk factor for oral cancer due to arecoline, its primary active component. Resveratrol, a non-flavonoid polyphenol, possesses anti-cancer properties. It has been shown to inhibit arecoline-induced oral malignant cells in preliminary experiments but the underlying mechanism remains unclear. This research therefore aimed to explore the potential therapeutic targets of resveratrol in treating arecoline-induced oral cancer.

METHODS

Data mining identified common targets and hub targets of resveratrol in arecoline-induced oral cancer. Gene set variation analysis (GSVA) was used to score and validate the expression and clinical significance of these hub targets in head and neck cancer (HNC) tissues. Molecular docking analysis was conducted on the hub targets. The effect of resveratrol intervention on hub targets was verified by experiments.

RESULTS

Sixty-one common targets and 15 hub targets were identified. Hub targets were highly expressed in HNC and were associated with unfavorable prognoses. They played a role in HNC metastasis, epithelial-mesenchymal transition, and invasion. Their expression also affected immune cell infiltration and correlated negatively with sensitivity to chemotherapeutic agents such as bleomycin and docetaxel. Experiments demonstrated that resveratrol down-regulated the expression of the hub targets, inhibited their proliferation and invasion, and induced apoptosis.

CONCLUSION

Resveratrol inhibits the arecoline-induced malignant phenotype of oral epithelial cells by regulating the expression of some target genes, suggesting that resveratrol may be used not only as an adjuvant treatment for oral cancer, but also as an adjuvant for oral cancer prevention due to its low toxicity and high efficacy. © 2024 Society of Chemical Industry.

Disulfidptosis: A new type of cell death

Disulfidptosis is a novel form of cell death that is distinguishable from established programmed cell death pathways such as apoptosis, pyroptosis, autophagy, ferroptosis, and oxeiptosis. This process is characterized by the rapid depletion of nicotinamide adenine dinucleotide phosphate (NADPH) in cells and high expression of solute carrier family 7 member 11 (SLC7A11) during glucose starvation, resulting in abnormal cystine accumulation, which subsequently induces andabnormal disulfide bond formation in actin cytoskeleton proteins, culminating in actin network collapse and disulfidptosis. This review aimed to summarize the underlying mechanisms, influencing factors, comparisons with traditional cell death pathways, associations with related diseases, application prospects, and future research directions related to disulfidptosis.

Exploring the correlation between innate immune activation of inflammasome and regulation of pyroptosis after intracerebral hemorrhage: From mechanism to treatment

Stroke has emerged as the primary cause of disability and death globally in recent years. Intracerebral hemorrhage (ICH), a particularly severe kind of stroke, is occurring in an increasing number of people. The two main clinical treatments for ICH now in use are conservative pharmaceutical therapy and surgical intervention, both of which have risks and drawbacks. Consequently, it is crucial to look into the pathophysiology of ICH and consider cutting-edge therapeutic approaches. Recent research has revealed that pyroptosis is a newly identified type of cell death distinguished by the break of the cell membrane and the discharge of pro-inflammatory substances through different routes. Following ICH, glial cells experience pyroptosis, which worsens neuroinflammation. Hence, the onset and progression of ICH are strongly linked to pyroptosis, which is facilitated by different inflammasomes. It is essential to conduct a comprehensive investigation of ICH damage processes and uncover new targets for treatment. The impact and function of pyroptosis in ICH, as well as the activation and regulation of inflammasomes and their mediated pyroptosis pathways will be fully discussed in this review.

The phthalide compound tokinolide B from Angelica sinensis exerts anti-inflammatory effects through Nur77 binding

BACKGROUND

Nur77, an orphan member of the nuclear receptor superfamily, regulates inflammatory diseases and is a therapeutic target for treating inflammation. Phthalides in Angelica sinensis exhibit anti-inflammatory activity.

PURPOSE

This study aimed to screen compounds from A. sinensis phthalide extract that could exert anti-inflammatory activity by targeting Nur77. To provide new theoretical support for better elucidation of Chinese medicine targeting mitochondria to achieve multiple clinical efficacies.

METHODS

The anti-inflammatory capacity of phthalides was assessed in tumor necrosis factor-alpha (TNF-α)-stimulated HepG2 cells using western blotting. The interaction between phthalides and Nur77 was verified by molecular docking, surface plasmon resonance, and cellular thermal shift assay. Co-immunoprecipitation, western blotting, and immunostaining were performed to determine the molecular mechanisms. The in vivo anti-inflammatory activity of the phthalides was evaluated in a lipopolysaccharide (LPS)/d-galactosamine (d-GalN)-induced acute hepatitis and liver injury mouse model of acute hepatitis and liver injury. Finally, the toxicity of phthalide toxicity was assessed in zebrafish experiments.

RESULTS

Among the 27 phthalide compounds isolated from A. sinensis, tokinolide B (TB) showed the best Nur77 binding capacity and, the best anti-inflammatory activity, which was induced without apoptosis. In vivo and in vitro experiments showed that TB promoted Nur77 translocation from the nucleus to the mitochondria and interacted with tumor necrosis factor receptor-associated factor 2 (TRAF2) and sequestosome 1 (p62) to induce mitophagy for anti-inflammatory functions. TB substantially inhibited LPS/d-GalN-induced acute hepatitis and liver injury in mice. TB also exhibited significantly lower toxicity than celastrol in zebrafish experiments.

CONCLUSION

These findings suggested that TB inhibits inflammation by promoting Nur77 interaction with TRAF2 and p62, thereby inducing mitophagy. These findings offer promising directions for developing novel anti-inflammatory agents, enhance the understanding of phthalide compounds, and highlight the therapeutic potential of traditional Chinese herbs.

The mechanism and promising therapeutic strategy of diabetic cardiomyopathy dysfunctions: Focus on pyroptosis

Diabetes is a major risk factor for cardiovascular diseases, and myocardial damage caused by hyperglycemia is the main cause of heart failure. However, there is still a lack of systematic understanding of myocardial damage caused by diabetes. At present, we believe that the cellular inflammatory damage caused by hyperglycemia is one of the causes of diabetic cardiomyopathy. Pyroptosis, as a proinflammatory form of cell death, is closely related to the occurrence and development of diabetic cardiomyopathy. Therefore, this paper focuses on the important role of inflammation in the occurrence and development of diabetic cardiomyopathy. From the perspective of pyroptosis, we summarize the pyroptosis of different types of cells in diabetic cardiomyopathy and its related signaling pathways. It also summarizes the treatment of diabetic cardiomyopathy, hoping to provide methods for the prevention and treatment of diabetic cardiomyopathy by inhibiting pyroptosis.

Overview of pyroptosis mechanism and in-depth analysis of cardiomyocyte pyroptosis mediated by NF-κB pathway in heart failure

The pyroptosis of cardiomyocytes has become an essential topic in heart failure research. The abnormal accumulation of these biological factors, including angiotensin II, advanced glycation end products, and various growth factors (such as connective tissue growth factor, vascular endothelial growth factor, transforming growth factor beta, among others), activates the nuclear factor-κB (NF-κB) signaling pathway in cardiovascular diseases, ultimately leading to pyroptosis of cardiomyocytes. Therefore, exploring the underlying molecular biological mechanisms is essential for developing novel drugs and therapeutic strategies. However, our current understanding of the precise regulatory mechanism of this complex signaling pathway in cardiomyocyte pyroptosis is still limited. Given this, this study reviews the milestone discoveries in the field of pyroptosis research since 1986, analyzes in detail the similarities, differences, and interactions between pyroptosis and other cell death modes (such as apoptosis, necroptosis, autophagy, and ferroptosis), and explores the deep connection between pyroptosis and heart failure. At the same time, it depicts in detail the complete pathway of the activation, transmission, and eventual cardiomyocyte pyroptosis of the NF-κB signaling pathway in the process of heart failure. In addition, the study also systematically summarizes various therapeutic approaches that can inhibit NF-κB to reduce cardiomyocyte pyroptosis, including drugs, natural compounds, small molecule inhibitors, gene editing, and other cutting-edge technologies, aiming to provide solid scientific support and new research perspectives for the prevention and treatment of heart failure.

Chronic environmental level exposure to perfluorooctane sulfonate overshadows graphene oxide to induce apoptosis through activation of the ROS-p53-caspase pathway in marine medaka Oryzias melastigma

The widespread occurrence of perfluorooctane sulfonate (PFOS) and the mass production and application of graphene oxide (GO) lead to their inevitable release and interaction in the environment, which may enhance associated toxic impacts on aquatic organisms. This study elucidates the induction of apoptosis by 60-day chronic single and mixture exposures to environmentally relevant levels of PFOS (0.5 μg/L and 5 μg/L) and GO (1 mg/L) in adult marine medaka Oryzias melastigma. Results showed a significant increase (p < 0.05) in reactive oxygen species (ROS) levels, the apoptotic positive rate in livers, and activities of caspases 3, 8, and 9 in all treated groups compared to the control. PFOS individual and PFOS-GO combined exposures significantly impacted fish growth, upregulated expressions of six apoptosis-related genes including p53, apaf1, il1b, tnfa, bcl2l1, bax, as well as enriched cell cycle and p53 signaling pathways (transcriptomic analysis) related to apoptosis compared to control group. Besides higher ROS production, GO also had a higher binding affinity to proteins than PFOS, especially to caspase 8 as revealed by molecular docking. Overall, PFOS induced ROS-p53-caspase apoptosis pathway through multi-gene regulation during single or mixture exposure, while GO single exposure induced apoptosis through tissue damage and ROS-caspase pathway activation and direct docking with caspase 8 to activate the caspase cascade. Under co-exposure, the PFOS-induced apoptotic pathway overshadowed the GO-induced pathway, due to competition for limited active sites on caspases. These findings will contribute to a better understanding of the apoptosis mechanism and ecological risks of nanomaterials and per- and polyfluoroalkyl substances in marine ecosystems.

Reuterin promotes pyroptosis in hepatocellular cancer cells through mtDNA-mediated STING activation and caspase 8 expression

Hepatocellular carcinoma (HCC) is the most common form of liver cancer with poor prognosis. The available drugs for advanced HCC are limited and substantial therapeutic advances including new drugs and new combination therapies are still in urgent need. In this study, we found that the major metabolite of Lactobacillus reuteri (L. reuteri), reuterin showed great anti-HCC potential and could help in sorafenib treatment. Reuterin treatment impaired mitophagy and caused the aberrant clustering of mitochondrial nucleoids to block mitochondrial DNA (mtDNA) replication and mitochondrial fission, which could promote mtDNA leakage and subsequent STING activation in HCC cells. STING could activate pyroptosis and necroptosis, while reuterin treatment also induced caspase 8 expression to inhibit necroptosis through cleaving RIPK3 in HCC cells. Thus, pyroptosis was the main death form in reuterin-treated HCC cells and STING suppression remarkably rescued the growth inhibitory effect of reuterin and concurrently knockdown caspase 8 synergized to restrain the induction of pyroptosis. In conclusion, our study explains the detailed molecular mechanisms of the antitumor effect of reuterin and reveals its potential to perform as a combinational drug for HCC treatment.

Applications of pyroptosis activators in tumor immunotherapy

Contemporary progress in tumor immunotherapy has solidified its role as an effective approach in combating cancer. Nonetheless, the prevalent "immune cold" state within the tumor microenvironment poses a substantial barrier to its efficacy. Addressing this, pyroptosis-a gasdermin-mediated programmed cell death characterized by its inflammatory profile-emerges as a crucial mechanism. It catalyzes the release of vast quantities of pro-inflammatory cytokines and immunogens, potentially transforming immunosuppressive "cold" tumors into reactive "hot" ones. Herein, we will initially present an overview of pyroptosis as a distinct form of cell death, along with its molecular mechanisms. Subsequently, we will focus on introducing how pyroptosis activators are utilized in the field of tumor immunotherapy. Insights gained from applications of pyroptosis activators in tumor immunotherapy could lead to the development of safe and efficient pyroptosis activators, significantly enriching the arsenal for tumor immunotherapy.

Identification of necroptosis genes and characterization of immune infiltration in non-alcoholic steatohepatitis

BACKGROUND

The most common progressive form of non-alcoholic fatty liver disease (NAFLD) is non-alcoholic steatohepatitis (NASH), which is characterized by the development of cirrhosis, and requires liver transplantation. We screened for the differentially expressed necroptosis-related genes in NASH in this study, and analyzed immune infiltration through microarray and bioinformatics analysis to identify potential biomarkers, and explore the molecular mechanisms involved in NASH.

METHODS

The GSE24807 microarray dataset of NASH patients and healthy controls was downloaded, and we identified the differentially expressed genes (DEGs). Necroptosis-related differential genes (NRDEGs) were extracted from these DEGs, and functionally annotated by enrichment analyses. The core genes were obtained by constructing gene co-expression networks using weighted gene co-expression network analysis (WGCNA). Finally, the transcription factor (TF) regulatory network and the mRNA-miRNA network were constructed, and the infiltrating immune cell populations were analyzed with CIBERSORT.

RESULTS

We identified six necroptosis-related genes (CASP1, GLUL, PYCARD, IL33, SHARPIN, and IRF9), and they are potential diagnostic biomarkers for NASH. In particular, PYCARD is a potential biomarker for NAFLD progression. Analyses of immune infiltration showed that M2 macrophages, γδ T cells, and T follicular helper cells were associated with the immune microenvironment of NASH, which is possibly regulated by CASP1, IL33, and IRF9.

CONCLUSIONS

We identified six necroptosis-related genes in NASH, which are also potential diagnostic biomarkers. Our study provides new insights into the molecular mechanisms and immune microenvironment of NASH.

Low Expression of CASP8 Could be a Prognostic Biomarker in Neuroblastoma Patients

The aim of study was to investigate whether CASP8 (CASPASE8) could be a biomarker for prognosis in neuroblastoma. The prognostic value of CASP8 was determined by analyzing CASP8 methylation status and gene expressions in the tumor tissues of 37 neuroblastoma patients. Bisulfite and quantitative multiplex-methylation-specific polymerase chain reaction (PCR) were used to identify the methylation status. CASP8 messenger ribonucleic acid (RNA) expression levels were determined using reverse transcriptase-quantitative PCR. CASP8 expression levels associated with prognostic value were also analyzed using the TARGET NBL (141 cases) database through PDX for Childhood Cancer Therapeutics (PCAT) and SEQC (498 cases) via the R2 platform. CASP8 methylation status was associated with risk groups, MYCN amplification, and 17q gain status. CASP8 expression was found to be statistically different between high- and low-risk neuroblastoma groups. Low expression of CASP8 was associated with MYCN amplification status. Low expression of CASP8 has shown statistically significant prognostic value through TARGET NBL and SEQC-498 data sets. CASP8 messenger RNA expressions and methylation status were associated with the MYCN amplified high-risk group in neuroblastoma. CASP8 messenger RNA expressions may be considered as a clinical prognostic marker in neuroblastoma.

Potential of CME@ZIF-8 MOF Nanoformulation: Smart Delivery of Silymarin for Enhanced Performance and Mechanism in Albino Rats

Silymarin, an antioxidant, is locally used for kidney and heart ailments. However, its limited water solubility and less oral bioavailability limit its therapeutic efficiency. The present study investigated the enhancement of solubility and bioavailability of silymarin by loading it in Cordia myxa plant extract-coated zeolitic imidazole framework (CME@ZIF-8) against carbon tetrachloride (CCl4)-induced nephrotoxicity and cardiac toxicity in albino rats. The synthesized PEG-coated silymarin drug-loaded CME@ZIF-8 MOFs (PEG-Sily@CME@ZIF-8) were characterized by scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, energy dispersive X-ray spectroscopy, UV-visible spectroscopy, X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, and zeta potential. The average crystal size of CME@ZIF-8 and PEG-Sily@CME@ZIF-8 was 12.69 and 16.81 nm, respectively. The silymarin drug loading percentage in PEG-Sily@CME@ZIF-8 was 33.05% (w/w). In the animal model with CCl4 treatment, different parameters like serum profile, enzymatic level, genotoxicity, and histopathology were assessed. Treatment with PEG-Sily@CME@ZIF-8 with different doses of 500, 1000, and 1500 μg/kg body weight efficiently ameliorated the alterations in the antioxidant defenses, biochemical parameters, and histopathological alterations and DNA damage in comparison to silymarin drug in a CCl4-induced toxicity rat model via alleviating the cellular abnormalities and attenuation of normal antioxidant enzymes levels. Moreover, the molecular mechanism of drug-silymarin interaction with the target protein was investigated. It involves the binding pockets of silymarin molecules with VEGFR, TNF-α, NLRP3, AT1R, NOX1, RIPK1, Caspase-3, CHOP, and MMP-9 proteins, elucidating the silymarin-protein interactions by the formation of hydrogen bonds and hydrophobic interactions. This study suggests that the nanodrug PEG-Sily@CME@ZIF-8 MOFs protect the kidneys and heart possibly by mitigating oxidative stress more efficiently than the conventional drug silymarin.

Inflammasomes and their role in PANoptosomes

Inflammasomes are multiprotein signaling structures in the innate immune system that drive cell death and inflammatory responses. These protein complexes generally comprise an innate immune sensor, the adaptor protein ASC, and the inflammatory protease caspase-1. Inflammasomes are formed when a cytosolic sensor, also known as a pattern recognition receptor, senses its cognate ligand, which can include microbial components, endogenous damage/danger signals, or environmental stimuli. Inflammasome assembly leads to autoproteolytic cleavage and activation of caspase-1. This activation, in turn, induces proteolytic maturation and release of the proinflammatory cytokines interleukin (IL)-1β and IL-18, and the activation of the pore-forming molecule gasdermin D to induce cell death, known as pyroptosis. Recent studies have identified inflammasomes as integral components of larger cell death complexes, known as PANoptosomes. These PANoptosomes regulate PANoptosis, an innate immune cell death pathway initiated by innate immune sensors and driven by caspases and receptor-interacting serine/threonine protein kinases. PANoptosome assembly and activation leads to cell lysis, inflammation, and the release of proinflammatory cytokines, damage-associated molecular patterns, and alarmins. In this review, we discuss the current understanding of different inflammasomes and their role in PANoptosomes.

Identification of a novel PANoptosis-related gene signature for predicting the prognosis in clear cell renal cell carcinoma

PANoptosis has been shown to play an important role in tumorigenesis and gain more attention. Yet, the prognostic significance of PANoptosis-related genes has not been investigated more in clear cell renal cell carcinoma (ccRCC). The aim of this research was designed to identify and create a signature of PANoptosis-related genes which was expected to predict prognosis of ccRCC more effectively. The transcriptome data and clinical information were collected from The Cancer Genome Atlas database and the Gene Expression Omnibus database. Optimal differentially expressed PANoptosis-related genes, which were closely associated with prognosis and employed to construct a risk score, were extracted by univariate Cox analysis, least absolute shrinkage and selection operator Cox regression and multivariate Cox analysis. We performed Kaplan-Meier survival analysis and time-dependent receiver operating characteristic curves to complete this process. By adopting univariate and multivariate analysis, the constructed risk score was assessed to verify whether it could be taken as an independent contributor for prognosis. Moreover, we created a nomogram in order to predict overall survival (OS) of ccRCC. Five differentially expressed PANoptosis-related genes were screened out and used to construct a risk score. Our results showed that ccRCC patients with high risk score had a poor prognosis and shorter OS. The results of Kaplan-Meier curves and the area under the receiver operating characteristic curves of 1-, 3-, and 5-year OS indicated that the prediction performance was satisfactory. Additionally, the risk model could be taken as an independent prognostic factor in training and validation cohorts. The nomogram exhibited excellent reliability in predicting OS, which was validated by calibration curves. We identified 5 PANoptosis-related genes, which were used to construct a risk score and a nomogram for prognostic prediction with reliable predictive capability. The present study may provide new potential therapeutic targets and precise treatment strategies for ccRCC.

Long-term PS micro/nano-plastic exposure: Particle size effects on hepatopancreas injury in Parasesarma pictum

With the widespread use of plastic products, microplastics and nanoplastics have emerged as prevalent pollutants in coastal aquatic ecosystems. Parasesarma pictum, a common estuarine crab species, was selected as a model organism. P. pictum was exposed to polystyrene (PS) particles of sizes 80 nm (80PS), 500 nm (500PS), and 1000 nm (1000PS), as well as to clean seawater (CK) for 21 days. Histological and fluorescent staining results showed that PS particles of all three sizes induced hepatopancreatic nuclear pyknosis, cell junction damage, and necrosis. The degree of damage was observed as 1000PS > 80PS > 500PS. Transcriptomic analysis revealed that major differentially expressed genes (DEGs) were associated with cellular processes, membrane components, and catalytic activity. The respiratory chain disruptions and immune exhaustion induced by 1000PS were notably stronger than those by 80PS and 500PS. Additionally, necrosis caused hepatopancreas injury in P. pictum rather than apoptosis or autophagy after long-term PS particle exposure. Furthermore, PS particles of all three sizes inhibited innate immunity, while the complement pathway was not significantly affected in the 80PS group. This study elucidated potential distinctions in how plastic particles of varying sizes (nanoplastics, microplastics, and micro/nanoplastics) impact P. pictum, providing a reference for toxicological mechanism research on microplastics and nanoplastics in aquatic organisms. Future research should focus on exploring long-term effects and potential mitigation strategies for microplastics and nanoplastics of more types and a wider range of particle size pollution in aquatic environments.

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.

An Overview of Hexavalent Chromium-Induced Necroptosis, Pyroptosis, and Ferroptosis

Heavy metals are common environmental industrial pollutants. Due to anthropogenic activity, chromium, especially its hexavalent form [Cr(VI)], is a widespread environmental contaminant that poses a threat to human health. In this review paper, we summarize the currently reported molecular mechanisms involved in chromium toxicity with a focus on the induction of pro-inflammatory non-apoptotic cell death pathways such as necroptosis, pyroptosis, and ferroptosis. The review highlights the ability of chromium to induce necroptosis, pyroptosis, and ferroptosis revealing the signaling pathways involved. Cr(VI) can induce RIPK1/RIPK3-dependent necroptosis both in vitro and in vivo. Chromium toxicity is associated with pyroptotic NLRP3 inflammasome/caspase-1/gasdermin D-dependent secretion of IL-1β and IL-18. Furthermore, this review emphasizes the role of redox imbalance and intracellular iron accumulation in Cr(VI)-induced ferroptosis. Of note, the crosstalk between the investigated lethal subroutines in chromium-induced toxicity is primarily mediated by reactive oxygen species (ROS), which are suggested to act as a rheostat determining the cell death pathway in cells exposed to chromium. The current study provides novel insights into the pro-inflammatory effects of chromium, since necroptosis, pyroptosis, and ferroptosis affect inflammation owing to their immunogenic properties linked primarily with damage-associated molecular patterns. Inhibition of these non-apoptotic lethal subroutines can be considered a therapeutic strategy to reduce the toxicity of heavy metals, including chromium.

Identifying new biomarkers and potential therapeutic targets for breast cancer through the integration of human plasma proteomics: a Mendelian randomization study and colocalization analysis

Background

The proteome is a crucial reservoir of targets for cancer treatment. While some targeted therapies have been developed, there are still significant challenges in early diagnosis and treatment, highlighting the need to identify new biomarkers and therapeutic targets for breast cancer. Therefore, we conducted a comprehensive proteome-wide Mendelian randomization (MR) study to identify novel biomarkers and potential therapeutic targets for breast cancer.

Methods

Protein quantitative trait locus (pQTL) data were extracted from two published plasma proteome-wide association studies. Genetic variants associated with breast cancer were obtained from the Breast Cancer Association Consortium, which included 133,384 cases and 113,789 controls, and the Finnish cohort study, comprising 18,786 cases and 182,927 controls. We employed summary-based MR and colocalization methods to identify potential drug targets for breast cancer, which were subsequently validated using a two-sample MR approach. Finally, a protein-protein interaction (PPI) network was constructed to detect interactions between the identified proteins and existing cancer drug targets.

Results

Gene-predicted levels of ten proteins were associated with breast cancer risk. Decreased levels of CASP8, DDX58, CPNE1, ULK3, PARK7, and BTN2A1, as well as increased levels of TNFRSF9, TNXB, DNPH1, and TLR1, were linked to an elevated risk of breast cancer. Among these, CASP8 and DDX58 were supported by tier-one evidence, while CPNE1, ULK3, PARK7, and TNFRSF9 received tier-two evidence support. The remaining proteins, TNXB, BTN2A1, DNPH1, and TLR1, were supported by tier-three evidence. CASP8, DDX58, CPNE1, ULK3, PARK7, and TNFRSF9 have already been identified as targets in drug development and potential therapeutic targets for breast cancer treatment. Additionally, ULK3 showed promise as a prognostic biomarker for breast cancer.

Conclusions

The present study identified several novel potential drug targets and biomarkers for breast cancer, providing new insights into its diagnosis and treatment. The integration of PPI and druggability evaluations enhances the prioritization of these therapeutic targets, paving the way for future drug development efforts.

Zinc oxide nanoparticles disrupt the mammary epithelial barrier via Z-DNA binding protein 1-triggered PANoptosis

Lactation women, a highly concerned demographic in society, face health risks that deserve attention. Zinc oxide nanoparticles (ZnO NPs) are widely utilized in food and daily products due to their excellent physicochemical properties, leading to the potential exposure of lactating women to ZnO NPs. Hence, assessing the potential risks associated with ZnO NP exposure during lactation is critical. While studies have confirmed that exposure to ZnO NPs during lactation can induce toxic responses in multiple organs through blood circulation, the effects of lactational exposure on mammary tissue remain unclear. This research investigated the impairment of mammary tissue induced by ZnO NPs and its potential mechanisms. Through administering multiple injections of ZnO NPs into the tail vein of lactating ICR mice, our study revealed that ZnO NPs can deposit in the mammary tissues, downregulating key components of mammary epithelial barrier such as ZO-1, occludin, and claudin-3. In vivo, we also found that ZnO NPs can simultaneously induce apoptosis, necroptosis, and pyroptosis, called PANoptosis. Additionally, using EpH4-Ev cells to simulate an in vitro mammary epithelial barrier model, we observed that ZnO NPs effectively disrupted the integrity of mammary epithelial barrier and induced PANoptosis. Furthermore, we confirmed that PANoptosis was responsible for the mammary epithelial barrier disruption induced by ZnO NPs. Moreover, we identified that ZBP1 was the primary mechanism of ZnO NPs inducing PANoptosis. These discoveries are designed to enhance our comprehension of the mechanisms underlying mammary epithelial barrier disruption caused by ZnO NPs, and we aim to highlight the potential hazards associated with daily usage and therapeutic exposure to ZnO NPs during lactation.

Nynrin preserves hematopoietic stem cell function by inhibiting the mitochondrial permeability transition pore opening

Mitochondria are key regulators of hematopoietic stem cell (HSC) homeostasis. Our research identifies the transcription factor Nynrin as a crucial regulator of HSC maintenance by modulating mitochondrial function. Nynrin is highly expressed in HSCs under both steady-state and stress conditions. The knockout Nynrin diminishes HSC frequency, dormancy, and self-renewal, with increased mitochondrial dysfunction indicated by abnormal mPTP opening, mitochondrial swelling, and elevated ROS levels. These changes reduce HSC radiation tolerance and promote necrosis-like phenotypes. By contrast, Nynrin overexpression in HSCs diminishes irradiation (IR)-induced lethality. The deletion of Nynrin activates Ppif, leading to overexpression of cyclophilin D (CypD) and further mitochondrial dysfunction. Strategies such as Ppif haploinsufficiency or pharmacological inhibition of CypD significantly mitigate these effects, restoring HSC function in Nynrin-deficient mice. This study identifies Nynrin as a critical regulator of mitochondrial function in HSCs, highlighting potential therapeutic targets for preserving stem cell viability during cancer treatment.

Azadirachtin Induces Fat Body Apoptosis by Suppressing Caspase-8 in the Fall Armyworm, Spodoptera frugiperda

Azadirachtin is a widely used botanical pesticide for agricultural pest control worldwide. However, the molecular mechanisms of azadirachtin in insects are not fully understood. In this study, histological analysis and RNA sequencing were conducted to investigate the impact of azadirachtin on the larval development of Spodoptera frugiperda. Under azadirachtin exposure, the development was completely inhibited, and the major internal tissues, fat body, and midgut were strongly damaged under histological analysis. Differential gene expression analysis demonstrated that nutrient absorption and detoxification metabolism-related genes are differentially expressed. Interestingly, the expression of the apoptosis-related gene, caspase-8, was significantly inhibited under exposure to azadirachtin. In addition, after knocking down the expression of the caspase-8 gene, the fat body displayed a similar apoptotic phenotype as azadirachtin treatment; the distribution of chromatin and lipid droplets was uneven in the fat body cells. Thus, the results in this study demonstrated that exposure to azadirachtin rapidly activates apoptosis, resulting in innate tissue disruption, ultimately arresting larval development in S. frugiperda.

Molecular mechanism and potential role of mitophagy in acute pancreatitis

Acute pancreatitis (AP) is a multifaceted inflammatory disorder stemming from the aberrant activation of trypsin within the pancreas. Despite the contribution of various factors to the pathogenesis of AP, such as trypsin activation, dysregulated increases in cytosolic Ca2+ levels, inflammatory cascade activation, and mitochondrial dysfunction, the precise molecular mechanisms underlying the disease are still not fully understood. Mitophagy, a cellular process that preserves mitochondrial homeostasis under stress, has emerged as a pivotal player in the context of AP. Research suggests that augmenting mitophagy can mitigate pancreatic injury by clearing away malfunctioning mitochondria. Elucidating the role of mitophagy in AP may pave the way for novel therapeutic strategies. This review article aims to synthesize the current research findings on mitophagy in AP and underscore its significance in the clinical management of the disorder.

Intranuclear Irradiation Inhibits Solid Tumor Growth by Upregulating Caspase8 and Activating Apoptosis

Radioimmunotherapy (RIT) is a novel and promising cancer treatment method, with ongoing research focusing on RIT antibody selection, radionuclides, treatment options, and benefited patient groups. As we dive into the mechanisms of tumor biology, a deeper exploration of how RIT affects tumor tissue is needed to provide new ways to improve clinical treatment outcome and patient prognosis. We labeled the anti-PD-L1 monoclonal antibody atezolizumab with iodine-131 (131I), separated and purified the labeled mAb with Sephadex G-25 medium gel filtration resin, and tested product stability. We detected the in vivo activity of 131I-PD-L1 mAb by analyzing its in vivo biodistribution and performing SPECT imaging and then set different treatment groups to study the effect of 131I-atezolizumab on the survival of tumor-bearing mice. Western blot, real-time quantitative PCR, and immunohistochemistry were used to detect the expression level of Caspase8 and Nlrp3 in tumor. TUNEL fluorescence staining was used to detect the apoptosis in the tumor. The radiopharmaceutical molecular probe 131I-atezolizumab showed high stability and in vivo biological activity. The treatment regimen adopted had a positive effect on the survival of tumor-bearing mice. 131I internal irradiation upregulated Caspase8 in tumor and ultimately inhibited solid tumor growth by activating apoptosis pathways. We also found a significant increase in the expression of NLRP3, which plays an important role in the pyroptosis pathway, in tumor. In summary, our data demonstrated that radiopharmaceuticals combined with immunotherapy affected tumor tissue by modulating relevant biological pathways, thereby achieving better antitumor effects compared with single therapy and providing new insights for promoting better patient prognosis and combination treatment strategies.

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.

Arsenic induces hepatotoxicity in chickens via PANoptosis pathway

Environmental pollution caused by arsenic or its compounds is called arsenic pollution. Arsenic pollution mainly comes from people's mining and smelting of arsenic compounds. In addition, the widespread use of arsenic compounds, such as the use and production of arsenic-containing pesticides, is also a source of arsenic contamination. Arsenic contamination leads to an increased risk of arsenic exposure, and the multi-organ toxicity induced by arsenic exposure is a global health problem. As a non-mammalian vertebrate with high nutrient levels, chickens readily absorb and accumulate arsenic from their food. Relevant studies have shown that arsenic exposure induces hepatotoxicity in chickens, and there has been a steady stream of research into the specific mechanisms involved. PANoptosis, a newly discovered and unique mode of programmed cell death (PCD) characterized by both apoptosis, cellular pyroptosis, and necroptosis. There are no studies to indicate whether chicken liver toxicity due to arsenic is associated with PANoptosis. Therefore, we established chicken animal models and chicken primary hepatocyte models exposed to different arsenic concentrations to dissect the role and mechanism of PANoptosis in arsenic exposure-induced hepatotoxicity in chickens. Our histopathological results showed that arsenic treatment caused dose-dependent damage to chicken liver structure. Meanwhile, different doses of arsenic treatment groups caused significant up-regulation of the protein level of ZBP1, a key factor of PANoptosis. And then consequently triggered the abnormal gene and protein expression levels of apoptosis-associated factors (Caspase-8, Caspase-7, Caspase-3), cellular pyroptosis-associated factors (NLRP3, ASC, GSDMD) and necroptosis-associated factors (RIPK1, RIPK3, MLKL). In conclusion, our study revealed that PANoptosis is involved in arsenic-induced chicken hepatotoxicity. Our findings provide a new perspective on the pathogenesis of arsenic exposure-induced hepatotoxicity in chickens.

Mycobacterium tuberculosis Utilizes Serine/Threonine Kinase PknF to Evade NLRP3 Inflammasome-driven Caspase-1 and RIPK3/Caspase-8 Activation in Murine Dendritic Cells

Dendritic cells (DCs) are crucial for initiating the acquired immune response to infectious diseases such as tuberculosis. Mycobacterium tuberculosis has evolved strategies to inhibit activation of the NLRP3 inflammasome in macrophages via its serine/threonine protein kinase, protein kinase F (PknF). It is not known whether this pathway is conserved in DCs. In this study, we show that the pknF deletion mutant of M. tuberculosis (MtbΔpknF) compared with wild-type M. tuberculosis-infected cells induces increased production of IL-1β and increased pyroptosis in murine bone marrow-derived DCs (BMDCs). As shown for murine macrophages, the enhanced production of IL-1β postinfection of BMDCs with MtbΔpknF is dependent on NLRP3, ASC, and caspase-1/11. In contrast to macrophages, we show that MtbΔpknF mediates RIPK3/caspase-8-dependent IL-1β production in BMDCs. Consistently, infection with MtbΔpknF results in increased activation of caspase-1 and caspase-8 in BMDCs. When compared with M. tuberculosis-infected cells, the IL-6 production by MtbΔpknF-infected cells was unchanged, indicating that the mutant does not affect the priming phase of inflammasome activation. In contrast, the activation phase was impacted because the MtbΔpknF-induced inflammasome activation in BMDCs depended on potassium efflux, chloride efflux, reactive oxygen species generation, and calcium influx. In conclusion, PknF is important for M. tuberculosis to evade NLRP3 inflammasome-mediated activation of caspase-1 and RIPK3/caspase-8 pathways in BMDCs.

Microglial activation and pyroptosis induced by nano-TiO2 in marine medaka brain

Recently, nano-titanium dioxide (nano-TiO2) has been widely distributed over surface water. However, there are few reports on its effects on the central nervous system of fish. In this study, we investigated whether nano-TiO2 enters the medaka brain after exposure and its effect on the brain. Marine medaka brains were examined after exposure to 0.01 g/L nano-TiO2 for 3, 10, and 20 d. Nano-TiO2-like particles were found in the telencephalon of treated fish. There was no obvious brain histopathological injury. The number of irregular mitochondria with absent cristae increased. Gene expression of the apoptosis-related genes, casp8, bcl2b, and bax, decreased significantly in the nano-TiO2 group at 3 d. In contrast, the pyroptosis-related genes, gsdmeb and casp1, and inflammation-related factor, il18, increased significantly. As an activated microglia marker, mRNA expression of cd68 increased significantly in the nano-TiO2 treated group. Moreover, CD68 protein expression also increased significantly at 10 d. Altogether, we show that nano-TiO2 can alter mitochondrial morphology in the telencephalon of medaka, leading to microglial activation and pyroptosis.

Ferroptosis and iron metabolism in diabetes: Pathogenesis, associated complications, and therapeutic implications

Diabetes mellitus is a complex chronic disease, considered as one of the most common metabolic disorders worldwide, posing a major threat to global public health. Ferroptosis emerges as a novel mechanism of programmed cell death, distinct from apoptosis, necrosis, and autophagy, driven by iron-dependent lipid peroxidation accumulation and GPx4 downregulation. A mounting body of evidence highlights the interconnection between iron metabolism, ferroptosis, and diabetes pathogenesis, encompassing complications like diabetic nephropathy, cardiomyopathy, and neuropathy. Moreover, ferroptosis inhibitors hold promise as potential pharmacological targets for mitigating diabetes-related complications. A better understanding of the role of ferroptosis in diabetes may lead to an improvement in global diabetes management. In this review, we delve into the intricate relationship between ferroptosis and diabetes development, exploring associated complications and current pharmacological treatments.

Role of gasotransmitters in necroptosis

Gasotransmitters are endogenous gaseous signaling molecules that can freely pass through cell membranes and transmit signals between cells, playing multiple roles in cell signal transduction. Due to extensive and ongoing research in this field, we have successfully identified many gasotransmitters so far, among which nitric oxide, carbon monoxide, and hydrogen sulfide are best studied. Gasotransmitters are implicated in various diseases related to necroptosis, such as cardiovascular diseases, inflammation, ischemia-reperfusion, infectious diseases, and neurological diseases. However, the mechanisms of their effects on necroptosis are not fully understood. This review focuses on endogenous gasotransmitter synthesis and metabolism and discusses their roles in necroptosis, aiming to offer new insights for the therapeutic approaches to necroptosis-associated diseases.

Cell life-or-death events in osteoporosis: All roads lead to mitochondrial dynamics

Mitochondria exhibit heterogeneous shapes and networks within and among cell types and tissues, also in normal or osteoporotic bone tissues with complex cell types. This dynamic characteristic is determined by the high plasticity provided by mitochondrial dynamics and is stemmed from responding to the survival and functional requirements of various bone cells in a specific microenvironments. In contrast, mitochondrial dysfunction, induced by dysregulation of mitochondrial dynamics, may act as a trigger of cell death signals, including common apoptosis and other forms of programmed cell death (PCD). These PCD processes consisting of tightly structured cascade gene expression events, can further influence the bone remodeling by facilitating the death of various bone cells. Mitochondrial dynamics, therefore, drive the bone cells to stand at the crossroads of life and death by integrating external signals and altering metabolism, shape, and signal-response properties of mitochondria. This implies that targeting mitochondrial dynamics displays significant potential in treatment of osteoporosis. Considerable effort has been made in osteoporosis to emphasize the parallel roles of mitochondria in regulating energy metabolism, calcium signal transduction, oxidative stress, inflammation, and cell death. However, the emerging field of mitochondrial dynamics-related PCD is not well understood. Herein, to bridge the gap, we outline the latest knowledge on mitochondrial dynamics regulating bone cell life or death during normal bone remodeling and osteoporosis.

Ginsenoside Rg2 Attenuates Aging-Induced Liver Injury via Inhibiting Caspase 8-Mediated Pyroptosis, Apoptosis and Modulating Gut Microbiota

Aging is an irresistible natural law of the progressive decline of body molecules, organs, and overall function with the passage of time, resulting in eventual death. World Health Organization data show that aging is correlated with a wide range of common chronic diseases in the elderly, and is an essential driver of many diseases. Panax Ginseng C.A Meyer is an ancient herbal medicine, which has an effect of "long service, light weight, and longevity" recorded in the ancient Chinese medicine book "Compendium of Materia Medica." Ginsenoside Rg2, the main active ingredient of ginseng, also exerts a marked effect on the treatment of liver injury. However, it remains unclear whether Rg2 has the potential to ameliorate aging-induced liver injury. Hence, exploring the hepatoprotective properties of Rg2 and its possible molecular mechanism by Senescence Accelerate Mouse Prone 8 (SAMP8) and gut microbiota. Our study demonstrated that Rg2 can inhibit pyroptosis and apoptosis through caspase 8, and regulate the gut-liver axis to alleviate liver inflammation by changing the composition of gut microbiota, thus improving aging-induced liver injury. These findings provide theoretical support for the pharmacological effects of ginsenosides in delaying aging-induced liver injury.

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.

RIPK3 and caspase-8 interpret cytokine signals to regulate ILC3 survival in the gut

Group 3 innate lymphoid cells (ILC3s) are abundant in the developing or healthy intestine to critically support tissue homeostasis in response to microbial colonization. However, intestinal ILC3s are reduced during chronic infections, colorectal cancer, or inflammatory bowel disease (IBD), and the mechanisms driving these alterations remain poorly understood. Here we employed RNA sequencing of ILC3s from IBD patients and observed a significant upregulation of RIPK3, the central regulator of necroptosis, during intestinal inflammation. This was modeled in mice where we found that intestinal ILC3s express RIPK3, with conventional (c)ILC3s exhibiting high RIPK3 and low levels of pro-survival genes relative to lymphoid tissue inducer (LTi)-like ILC3s. ILC3-specific RIPK3 is promoted by gut microbiota, further upregulated following enteric infection, and dependent upon IL-23R and STAT3 signaling. However, lineage-specific deletion of RIPK3 revealed a redundant role in ILC3 survival, due to a blockade of RIPK3-mediated necroptosis by caspase 8, which was also activated in response to enteric infection. In contrast, lineage-specific deletion of caspase 8 resulted in loss of cILC3s from the healthy intestine and all ILC3 subsets during enteric infection, which increased pathogen burdens and gut inflammation. This function of caspase 8 required catalytic activity induced by TNF or TL1A and was dispensable if RIPK3 was simultaneously deleted. Caspase 8 activation and cell death were associated with increased Fas on ILC3s, and the Fas-FasL pathway was upregulated by cILC3s during enteric infection, which could restrain the abundance of intestinal ILC3s. Collectively, these data reveal that interpretation of key cytokine signals controls ILC3 survival following microbial challenge, and that an imbalance of these pathways, such as in IBD or across ILC3 subsets, provokes depletion of tissue-protective ILC3s from the inflamed intestine.

METTL3 restricts RIPK1-dependent cell death via the ATF3-cFLIP axis in the intestinal epithelium

Intestinal epithelial cells (IECs) are pivotal for maintaining intestinal homeostasis through self-renewal, proliferation, differentiation, and regulated cell death. While apoptosis and necroptosis are recognized as distinct pathways, their intricate interplay remains elusive. In this study, we report that Mettl3-mediated m6A modification maintains intestinal homeostasis by impeding epithelial cell death. Mettl3 knockout induces both apoptosis and necroptosis in IECs. Targeting different modes of cell death with specific inhibitors unveils that RIPK1 kinase activity is critical for the cell death triggered by Mettl3 knockout. Mechanistically, this occurs via the m6A-mediated transcriptional regulation of Atf3, a transcription factor that directly binds to Cflar, the gene encoding the anti-cell death protein cFLIP. cFLIP inhibits RIPK1 activity, thereby suppressing downstream apoptotic and necroptotic signaling. Together, these findings delineate the essential role of the METTL3-ATF3-cFLIP axis in homeostatic regulation of the intestinal epithelium by blocking RIPK1 activity.

Exploring caspase functions in mouse models

Caspases are enzymes with protease activity. Despite being known for more than three decades, caspase investigation still yields surprising and fascinating information. Initially associated with cell death and inflammation, their functions have gradually been revealed to extend beyond, targeting pathways such as cell proliferation, migration, and differentiation. These processes are also associated with disease mechanisms, positioning caspases as potential targets for numerous pathologies including inflammatory, neurological, metabolic, or oncological conditions. While in vitro studies play a crucial role in elucidating molecular pathways, they lack the context of the body's complexity. Therefore, laboratory animals are an indispensable part of successfully understanding and applying caspase networks. This paper aims to summarize and discuss recent knowledge, understanding, and challenges in caspase knock-out mice.

Breviscapine Reduces Sepsis-Induced Acute Lung Injury by Targeting CASP8 to Regulate Neutrophil Apoptosis and Inflammation

Background

Breviscapine has been demonstrated to have beneficial effects in ameliorating acute lung injury (ALI), yet its potential therapeutic value and molecular mechanisms in sepsis-induced ALI remain unexplored.

Methods

We utilized network pharmacology approach to identify the potential targets and mechanisms of breviscapine in treating sepsis-induced ALI. To construct a murine model of sepsis, we performed cecal ligation and puncture (CLP). Hematoxylin and eosin (HE) staining and enzyme-linked immunosorbent assay (ELISA) were employed to respectively determine the pathologic changes and levels of inflammatory factors. Neutrophil count and total protein level in bronchoalveolar lavage fluid (BALF) were detected by corresponding kit. Additionally, we utilized flow cytometry, immunofluorescence, Western blotting, and real-time reverse transcription PCR (qRT-PCR) to detect cell apoptosis, protein expression, and gene expression. Finally, we used ELISA kits to detect the activity of myeloperoxidase (MPO) and caspase-8 (CASP8).

Results

Breviscapine was revealed to target 81 potential proteins in the treatment of sepsis-induced ALI, while CASP8 was the most important one as demonstrated by network analysis. In vivo experiments demonstrated that breviscapine effectively reduced the severity of sepsis-induced ALI and inflammation, and significantly suppressed neutrophil infiltration in the lung tissues of CLP mice and promoted neutrophil apoptosis in the peripheral blood. In vitro experiments revealed that lipopolysaccharide (LPS)-induced neutrophil apoptosis was inhibited, and the expression and activity of CASP8 were down-regulated. Breviscapine intervention markedly up-regulated the expression and activity of CASP8, consequently activating neutrophil apoptosis and inhibiting inflammatory response by activating the NF-κB signaling pathway.

Conclusion

Breviscapine is remarkably effective in improving sepsis-induced ALI, and its mechanism of action may be to induce neutrophil apoptosis, inhibit inflammatory overreaction and reduce its infiltration in pulmonary tissues by up-regulating the expression and activity of CASP8.

DL-3-n-Butylphthalide Ameliorates Post-stroke Emotional Disorders by Suppressing Neuroinflammation and PANoptosis

Post-stroke emotional disorders such as post-stroke anxiety and post-stroke depression are typical symptoms in patients with stroke. They are closely associated with poor prognosis and low quality of life. The State Food and Drug Administration of China has approved DL-3-n-butylphthalide (NBP) as a treatment for ischemic stroke (IS). Clinical research has shown that NBP alleviates anxiety and depressive symptoms in patients with IS. Therefore, this study explored the role and molecular mechanisms of NBP in cases of post-stroke emotional disorders using network pharmacology and experimental validation. The results showed that NBP treatment significantly increased the percentage of time spent in the center of the middle cerebral artery occlusion (MCAO) rats in the open field test and the percentage of sucrose consumption in the sucrose preference test. Network pharmacology results suggest that NBP may regulate neuroinflammation and cell death. Further experiments revealed that NBP inhibited the toll-like receptor 4/nuclear factor kappa B signaling pathway, decreased the level of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-1β, and interleukin-6, and M1-type microglia markers (CD68, inducible nitric oxide synthase), and reduced the expression of PANoptosis-related molecules including caspase-1, caspase-3, caspase-8, gasdermin D, and mixed lineage kinase domain-like protein in the hippocampus of the MACO rats. These findings demonstrate that the mechanisms through which NBP ameliorates post-stroke emotional disorders in rats are associated with inhibiting neuroinflammation and PANoptosis, providing a new strategy and experimental basis for treating post-stroke emotional disorders.

The TRIF-RIPK1-Caspase-8 signalling in the regulation of TLR4-driven gene expression

The inflammatory response is tightly regulated to eliminate invading pathogens and avoid excessive production of inflammatory mediators and tissue damage. Caspase-8 is a cysteine protease that is involved in programmed cell death. Here we show the TRIF-RIPK1-Caspase-8 is required for LPS-induced CYLD degradation in macrophages. TRIF functions in the upstream of RIPK1. The homotypic interaction motif of TRIF and the death domain of RIPK1 are essential for Caspase-8 activation. Caspase-8 cleaves CYLD and the D235A mutant is resistant to the protease activity of Caspase-8. TRIF and RIPK1 serve as substrates of Capase-8 in vitro. cFLIP interacts with Caspase-8 to modulate its protease activity on CYLD and cell death. Deficiency in TRIF, Caspase-8 or CYLD can lead to a decrease or increase in the expression of genes encoding inflammatory cytokines. Together, the TRIF-Caspase-8 and CYLD play opposite roles in the regulation of TLR4 signalling.

Sphingolipid metabolism and regulated cell death in malignant melanoma

Malignant melanoma (MM) is a highly invasive and therapeutically resistant skin malignancy, posing a significant clinical challenge in its treatment. Programmed cell death plays a crucial role in the occurrence and progression of MM. Sphingolipids (SP), as a class of bioactive lipids, may be associated with many kinds of diseases. SPs regulate various forms of programmed cell death in tumors, including apoptosis, necroptosis, ferroptosis, and more. This review will delve into the mechanisms by which different types of SPs modulate various forms of programmed cell death in MM, such as their regulation of cell membrane permeability and signaling pathways, and how they influence the survival and death fate of MM cells. An in-depth exploration of the role of SPs in programmed cell death in MM aids in unraveling the molecular mechanisms of melanoma development and holds significant importance in developing novel therapeutic strategies.

Yinchenhao Decoction mitigates intestinal impairment induced by high carbohydrate diet in largemouth bass (Micropterus salmoides): insights from inflammation, apoptosis, oxidative stress, tight junctions, and microbiota homeostasis

As a major source of energy, carbohydrates have a protein-saving effect. However, excessive consumption of carbohydrates can lead to the disruption of the intestinal barrier in fish, especially for carnivorous fish. Therefore, traditional Chinese medicine component Yinchenhao Decoction (YD), was used to detect the effect on intestinal barriers and microbial community equilibrium for largemouth bass in current research. In this research, a series of NC (normal carbohydrate diet) and HC (high carbohydrate diet) with graded YD treatments during 10 weeks feeding trial. Results suggested that 2% and 4% YD treatments significantly reduced gut inflammation and mucosal loss caused by HC. Compared with NC, HC significantly decreased the relative expression of intestinal tight junction-related genes (zo1, claudin1, claudin7, and occludin). However, with the application of YD, the expression of tight junction-related genes (zo1, claudin1, and claudin7) increased significantly (p < 0.05). Likewise, administration of YD significantly reduced elevated plasma diamine oxidase (DAO) activity caused by HC (p < 0.05). Additionally, YD significantly downregulated the mRNA expression of endoplasmic reticulum stress (ERS)-related genes (grp78, atf6, chopα, ire1, xbp1, and eifα) and pro-apoptosis genes (casp3, casp8, and bax) (p < 0.05), while upregulating the anti-apoptosis gene bcl2 (p < 0.05). Moreover, YD significantly increased the mRNA expression of antioxidant genes and the enzyme activities of CAT and GPX, while decreased MDA concentration significantly (p < 0.05). Whereas, YD markedly decreased the expression of pro-inflammatory genes (il1β, tnfα, il8, and nf-κB) and the immune enzymes activity (ACP and AKP) (p < 0.05) by up-regulating the expression of anti-inflammatory genes (ikb and il10). Notably, YD modulated the largemouth bass intestinal microbial community, enhanced the diversity and increased the abundance of probiotic microorganisms in the intestinal microbiota. In summary, YD supplementation in HC alleviated inflammation, apoptosis, oxidative stress, tight-junction injury, and microbiota disequilibrium in the intestine, which suggested that YD could be a valuable functional additive in aquaculture.

Apoptotic signaling pathways in bone metastatic lung cancer: a comprehensive analysis

This review provides a comprehensive analysis of apoptotic signaling pathways in the context of bone metastatic lung cancer, emphasizing the intricate molecular mechanisms and microenvironmental influences. Beginning with an overview of apoptosis in cancer, the paper explores the specific molecular characteristics of bone metastatic lung cancer, highlighting alterations in apoptotic pathways. Focused discussions delve into key apoptotic signaling pathways, including the intrinsic and extrinsic pathways, and the roles of critical molecular players such as Bcl-2 family proteins and caspases. Microenvironmental factors, such as the tumor microenvironment, extracellular matrix interactions, and immune cell involvement, are examined in depth. The review also addresses experimental approaches and techniques employed in studying apoptotic signaling, paving the way for a discussion on current therapeutic strategies, their limitations, and future prospects. This synthesis contributes a holistic understanding of apoptosis in bone metastatic lung cancer, offering insights for potential therapeutic advancements.

Inflammatory caspase substrate specificities

Caspases are a family of cysteine proteases that act as molecular scissors to cleave substrates and regulate biological processes such as programmed cell death and inflammation. Extensive efforts have been made to identify caspase substrates and to determine factors that dictate substrate specificity. Thousands of putative substrates have been identified for caspases that regulate an immunologically silent type of cell death known as apoptosis, but less is known about substrates of the inflammatory caspases that regulate an immunostimulatory type of cell death called pyroptosis. Furthermore, much of our understanding of caspase substrate specificities is derived from work done with peptide substrates, which do not often translate to native protein substrates. Our knowledge of inflammatory caspase biology and substrates has recently expanded and here, we discuss the recent advances in our understanding of caspase substrate specificities, with a focus on inflammatory caspases. We highlight new substrates that have been discovered and discuss the factors that engender specificity. Recent evidence suggests that inflammatory caspases likely utilize two binding interfaces to recognize and process substrates, the active site and a conserved exosite.

The mechanosensitive Piezo1 channel exacerbates myocardial ischaemia/reperfusion injury by activating caspase-8-mediated PANoptosis

PANoptosis is a newly discovered type of cell death characterized by pyroptosis, apoptosis and/or necroptosis and has been implicated in the inflammatory response. Piezo1 is a mechanosensitive ion channel that plays important roles in physiological development and various diseases. However, whether cardiomyocytes undergo PANoptosis during myocardial ischaemia/reperfusion (I/R) injury and the role of Piezo1 in this process remain largely unexplored. In this study, our results revealed that the expression levels of the main components of the PANoptosome, including caspase-8, caspase-3, NLRP3, caspase-1, GSDMD, RIPK1, RIPK3 and MLKL, were significantly upregulated in I/R heart tissues over time, indicating the occurrence of PANoptosis in I/R hearts. Accordingly, Piezo1 expression was significantly upregulated in I/R-injured hearts and hypoxia/reoxygenation (H/R)-treated cardiomyocytes. In contrast, pharmacological inhibition of Piezo1 by the inhibitor GsMTx4 in mice markedly attenuated the I/R-mediated decline in cardiac contractile function and increases in infarct size, apoptosis, oxidative stress and inflammation accompanied by the inhibition of PANoptosis-related mediators in I/R hearts. Consistently, the effects of Piezo1 on calcium influx and PANoptosis were further verified by GsMTx4 and Piezo1 activator Yoda1 in H/R-treated cardiomyocytes in vitro. Moreover, caspase-8 rather than calcium influx was required for H/R-induced PANoptosis in vitro. Mechanistically, Piezo1 interacts with caspase-8, a key initial activator of the PANoptosome complex, which subsequently activates cardiomyocyte PANoptosis, leading to cardiac dysfunction. In summary, these data suggest that Piezo1 is a new cardiac mechanosensor that promotes cardiac I/R injury possibly through the caspase-8-mediated activation of cardiomyocyte PANoptosis and highlight that Piezo1 may represent a new target for treating ischaemic heart disease.

Circulating inflammatory factors and risk causality associated with type 2 diabetic nephropathy: A Mendelian randomization and bioinformatics study

The main causative factors of diabetic nephropathy (DN), a common complication of diabetes mellitus, are metabolic abnormalities and hemodynamic changes. However, studies have shown that the immune-inflammatory response also plays an important role in DN pathogenesis. Therefore, in this study, we analyzed the causal relationship and immune infiltration between inflammatory factors and DN using Mendelian randomization (MR) and bioinformatics techniques. We analyzed the causal relationship between 91 inflammatory factors and DN using two-sample MR dominated by the results of inverse variance-weighted analysis. Based on the MR analysis, the immune mechanism of inflammatory factors in DN was further explored using immune cell infiltration analysis. MR analysis indicated a positive causal relationship between DN and IL1A, caspase 8 (CASP8), macrophage colony-stimulating factor 1, IL10, STAM-binding protein, and tumor necrosis factor ligand superfamily member 12 (TNFSF12) and a negative causal relationship between DN and cystatin D, fibroblast growth factor 19, neurturin, and TNFSF14. The pathogenic mechanism of CASP8 may involve the recruitment of CD4+ T cells and macrophages for DN infiltration. In this study, we found a causal relationship between DN and IL1A, CASP8, macrophage colony-stimulating factor 1, IL10, STAM-binding protein, TNFSF12, cystatin D, fibroblast growth factor 19, neurturin, and TNFSF14. Bioinformatic immune infiltration analysis further revealed that CASP8 regulates DN by influencing the infiltration of immune cells, such as T cells and macrophages.

The protease caspase-1: Activation pathways and functions

Caspase-1 is one of the main mediators of inflammatory caspases and has become a correspondent with inflammation, cell death, and several inflammatory diseases. In this review, we systematically summarize both original and recent advances in caspase-1 to provide references for a better understanding of the molecular mechanisms in its activation and functions. This study investigates and summarizes the published articles concerning caspase-1, inflammation, pyroptosis, apoptosis, and cell death by searching academic search systems, including the PubMed, Web of Science, and Google Scholar. Caspase-1 is one of the main mediators of inflammatory caspases and has become a correspondent with inflammation and cell death. In cell death, caspase-1 was originally found to cause apoptosis in fibroblasts. Importantly, caspase-1 was later reported to execute programmed cell death, including pyroptosis and apoptosis, in many immune cells in response to diverse stimuli. It is widely established that different pathways can activate caspase-1 and subsequently mediate cell death and inflammation. It has become increasingly clear that caspase-1 is responsible for the initiation and control of pyroptosis, apoptosis, and inflammation in addition to its well-known function in cleaving IL-1β. The significant advancement in the understanding of caspase-1-controlled cell death and novel substrates inspires new therapeutic approaches in the future.