Function and Regulation of Noncanonical Caspase-4/5/11 Inflammasome

The role of pyroptosis in environmental pollutants-induced multisystem toxicities

The global ecosystem is adversely affected by environmental pollutants, which have numerous deleterious consequences on both the environment and human health. A multitude of human organs and systems, including the neurological, digestive, cardiovascular, reproductive, and respiratory systems, can be adversely affected by these pollutants. Pyroptosis is a form of programmed cell death, primarily involving the Caspase-1/Gasdermin D (GSDMD) classical inflammasome pathway, Caspase-4/5/11/GSDMD non-classical inflammasome pathway, Caspase-3/8 pathway, and other signaling pathways, which induce cell death and regulate the occurrence of inflammatory responses. Pyroptosis plays an important role in a range of diseases, including cancer, neurodegenerative diseases and cardiovascular disease. Evidence has emerged in recent years indicating that environmental pollutants exert various toxic effects by modulating pyroptosis. In this review, we examine hepatotoxicity, cardiovascular toxicity, nephrotoxicity, neurotoxicity, pulmonary toxicity, reproductive toxicity and the related mechanisms caused by environmental pollutants through the regulation of pyroptosis. We aim to provide theoretical references for future toxicity research on environmental pollutants.

A new type of Caspase-1 upon recognizing bacteria inhibits GSDME-dependent histone modification and NF-κB signaling

In the present study, a new type of Caspase-1 homolog is identified from Crassostrea gigas (defined as CgCas1-2D). It is composed of 2×DSRM-CASc domain and has closer evolutionary relationship with mammalian Caspase-1s. The mRNA expressions of CgCas1-2D increase significantly after Vibrio splendidus or LPS stimulation. Recombinant CgCas1-2D and its 2×DSRM and CASc domains all bind various PAMPs and bacteria. rCgCas1-2D shows the highest binding activity to human Caspase-1 substrate. Upon recognizing bacteria, CgCas1-2D co-localizes and interacts with CgGSDME, while it has no cleavage activity to CgGSDME. CgCas1-2D inhibits the histone methylation and acetylation levels and CgNF-κB/Rel nuclear translocation mediated by CgGSDME. In addition, CgCas1-2D suppresses the mRNA expression levels of cytokines mediated by GSDME-NF-κB/Rel axis. The results demonstrate that a new type of anti-inflammatory Caspase-1 identified from oyster upon recognizing various bacteria interacts with GSDME to inhibit the histone modification and NF-κB signaling to suppress the inflammation.

Microbial characteristics of gut microbiome dysbiosis in patients with chronic liver disease

BACKGROUND

In this study, we are committed to exploring the characteristics of the gut microbiome in three different stages of chronic liver disease (CLD): Chronic hepatitis B, liver cirrhosis, and hepatocellular carcinoma (HCC).

AIM

To delineate the gut microbiota traits in individuals with chronic liver ailments (chronic hepatitis B, cirrhosis, HCC), scrutinizes microbiome alterations during the progression of these diseases, and assesses microbiome disparities among various Child-Pugh categories in cirrhosis sufferers.

METHODS

A cohort of 60 CLD patients from the Third People’s Hospital of Yunnan Province were recruited from February to August 2023, together with 37 healthy counterparts. Employing 16SrDNA high-throughput sequencing, we evaluated the diversity and composition of the gut microbiota.

RESULTS

Compared to healthy subjects, patients exhibited a reduced presence of Firmicutes and a corresponding decline in butyrate-producing genera. In contrast, an upsurge in Proteobacteria was observed in the diseased cohorts, particularly an increase in Enterobacteriaceae that intensified with the disease's progression. At the genus level, the occurrence of Escherichia_Shigella, Parabacteroides, Streptococcus, Klebsiella, and Enterococcus was higher, with Escherichia_Shigella numbers augmenting as the disease advanced. Furthermore, in cirrhosis patients, an increase in Proteobacteria was noted as liver reserve diminished, alongside a decrease in Ruminococcaceae and Bacteroidaceae.

CONCLUSION

The reduced abundance of short-chain fatty acid-producing bacteria in the intestine, alongside the increased abundance of gram-negative bacteria such as Escherichia_Shigella and Parabacteroides, may promote the progression of CLD.

NLRP3 Inflammasome-mediated pyroptosis in acute lung injury: Roles of main lung cell types and therapeutic perspectives

The NLRP3 inflammasome plays a pivotal role in the pathogenesis of acute lung injury (ALI) by regulating pyroptosis, a highly inflammatory form of programmed cell death. NLRP3-mediated pyroptosis leads to alveolar epithelial cell injury, increased pulmonary microvascular endothelial permeability, excessive alveolar macrophage activation, and neutrophil dysfunction, collectively driving ALI progression. In addition to the classical NLRP3-dependent pathway, the non-canonical pyroptosis pathway (caspase-4/5/11) also contributes to ALI by inducing pyroptotic cell death in AECs and ECs, further amplifying NLRP3 activation through damage-associated molecular patterns (DAMP) release. Moreover, neutrophils (NE) pyroptosis exhibits dual roles in ALI, as it enhances pathogen clearance but also exacerbates excessive inflammation and tissue damage, highlighting the complexity of its regulation. Targeting the NLRP3 inflammasome and pyroptotic pathways has emerged as a promising therapeutic strategy for ALI. Various NLRP3 inhibitors (e.g., MCC950, CY-09, OLT1177) and pyroptosis inhibitors have demonstrated significant anti-inflammatory and tissue-protective effects in preclinical models. However, the clinical translation of NLRP3-targeted therapies remains challenging due to off-target effects, potential immunosuppression, lack of patient stratification strategies, and compensatory activation of alternative inflammasomes (e.g., AIM2, NLRC4). Future studies should focus on optimizing the selectivity of NLRP3 inhibitors, developing personalized therapeutic approaches, and exploring combination strategies to enhance their clinical applicability in ALI.

Targeting pyroptosis for cancer immunotherapy: mechanistic insights and clinical perspectives

Pyroptosis is a distinct form of programmed cell death characterized by the rupture of the cell membrane and robust inflammatory responses. Increasing evidence suggests that pyroptosis significantly affects the tumor microenvironment and antitumor immunity by releasing damage-associated molecular patterns (DAMPs) and pro-inflammatory mediators, thereby establishing it as a pivotal target in cancer immunotherapy. This review thoroughly explores the molecular mechanisms underlying pyroptosis, with a particular focus on inflammasome activation and the gasdermin family of proteins (GSDMs). It examines the role of pyroptotic cell death in reshaping the tumor immune microenvironment (TIME) involving both tumor and immune cells, and discusses recent advancements in targeting pyroptotic pathways through therapeutic strategies such as small molecule modulators, engineered nanocarriers, and combinatory treatments with immune checkpoint inhibitors. We also review recent advances and future directions in targeting pyroptosis to enhance tumor immunotherapy with immune checkpoint inhibitors, adoptive cell therapy, and tumor vaccines. This study suggested that targeting pyroptosis offers a promising avenue to amplify antitumor immune responses and surmount resistance to existing immunotherapies, potentially leading to more efficacious cancer treatments.

Inflammasomes and autophagy in cancer: unlocking targeted therapies

This study clarifies the interaction between autophagy and inflammasome within the cancer framework. The inflammasome generates pro-inflammatory cytokines to direct the immune response to pathogens and cellular stressors. Autophagy maintains cellular homeostasis and can either promote or inhibit cancer. These pathways interact to affect tumorigenesis, immune responses, and therapy. Autophagy controls inflammasome activity by affecting cancer pathogenesis and tumor microenvironment inflammation, highlighting novel cancer therapeutic approaches. Recent studies indicate that modulating autophagy and inflammasome pathways can boost anti-cancer immunity, reduce drug-resistance, and improve therapeutic efficacy. Recent studies indicate modulating inflammasome and autophagy pathways can augment anti-cancer immunity, mitigate therapy resistance, and improve treatment efficacy. Cancer research relies on understanding the inflammasome-autophagy relationship to develop targeted therapies that enhance anti-tumor efficacy and reduce inflammatory symptoms. Customized therapies may improve outcomes based on autophagy gene variations and inflammasome polymorphisms. This study investigates autophagy pathways and the inflammasome in tumor immunopathogenesis, cytokine function, and cancer therapeutic strategies, highlighting their significance in cancer biology and treatment.

Shuxuetong injection inhibits pyroptosis in acute ischemic stroke via CD44/NLRP3/GSDMD signal

ETHNOPHARMACOLOGICAL RELEVANCE

Acute ischemic stroke (AIS) is an important cause of death and disability in the world. Based on the blood stasis syndrome of stroke, Shuxuetong Injection (SXT) is a representative prescription for the treatment of AIS, which extracted by modern technology from Whitmania pigra Whitman (Shuizhi) and Pheretima aspergillum E.Perrier (Dilong).

AIM OF THE STUDY

This study is in order to examine whether SXT regulates pyroptosis in AIS via Cluster of Differentiation 44 (CD44)/NOD-like receptor thermal protein domain associated protein 3 (NLRP3)/gasdermin D (GSDMD) signal.

MATERIALS AND METHODS

The rats were randomly divided into sham group, model (transient middle cerebral artery occlusion, 24 h) group, SXT low-dose group (0.27 mL/kg), SXT medium-dose group (0.54 mL/kg), SXT high-dose group (1.08 mL/kg) and positive drug group (edaravone injection, 1.35 mL/kg). Transient middle cerebral artery occlusion (tMCAO, 24 h) model of rats was set up. Neurological deficit score, tetrazolium red staining, hematoxylin-eosin staining, and Nissl staining were used to observe and screen out the optimal dosage for improving AIS. Mechanism research indicators included transmission electron microscopy and Western blot. Adeno-associated virus (AAV)-CD44 and small interfering RNA (siRNA) of CD44 were used for knocking down the CD44 expression level to verify whether SXT could resist pyroptosis through CD44. The oxygen and glucose deprivation/re-oxygenation (OGD/R, 24 h) model of PC12 cells was used for in vitro pharmacological validation. Molecular docking, cellular thermal shift assay and drug affinity responsive target stability were employed to assess the binding affinity of critical components for the CD44 protein.

RESULTS

SXT conspicuously mitigated the neurological function scores and cerebral infarct volume in tMCAO rats, thereby safeguarding nerve cells. In vitro, SXT not only enhanced the viability of PC12 cells subjected to OGD/R but also mitigated cellular swelling and inflammatory infiltration. The optimal dose was 1.08 mL/kg (rats) or 72.56 mg/mL (PC12 cells). SXT reduced pyroptosis and inflammation in tMCAO rats and OGD/R cells by decreasing the expression levels of GSDMD-N, NLRP3 and CD44. In addition, after knocking down the expression level of CD44 by using AAV-CD44 and siRNA-CD44, it was found that the pyroptosis of AIS intervened by SXT was closely related to the CD44/NLRP3/GSDMD signal. The pivotal constituent of SXT, xanthine, exhibited pronounced binding affinity towards the CD44 protein, thereby demonstrating the capacity to stabilize this molecular target.

CONCLUSION

This study demonstrates that Shuxuetong Injection inhibits pyroptosis in acute ischemic stroke via CD44/NLRP3/GSDMD signal.

Pyroptosis for osteoarthritis treatment: insights into cellular and molecular interactions inflammatory

Osteoarthritis (OA) is a widely prevalent chronic degenerative disease often associated with significant pain and disability. It is characterized by the deterioration of cartilage and the extracellular matrix (ECM), synovial inflammation, and subchondral bone remodeling. Recent studies have highlighted pyroptosis-a form of programmed cell death triggered by the inflammasome-as a key factor in sustaining chronic inflammation. Central to this process are the inflammatory cytokines interleukin-1β (IL-1β) and interleukin-18 (IL-18), which play crucial roles mediating intra-articular pyroptosis through the NOD-like receptor protein 3 (NLRP3) inflammasome. This paper investigates the role of the pyroptosis pathway in perpetuating chronic inflammatory diseases and its linkage with OA. Furthermore, it explores the mechanisms of pyroptosis, mediated by nuclear factor κB (NF-κB), the purinergic receptor P2X ligand-gated ion channel 7 (P2X7R), adenosine monophosphate (AMP)-activated protein kinase (AMPK), and hypoxia-inducible factor-1α (HIF-1α). Additionally, it examines the interactions among various cellular components in the context of OA. These insights indicate that targeting the regulation of pyroptosis presents a promising therapeutic approach for the prevention and treatment of OA, offering valuable theoretical perspectives for its effective management.

Cell death in acute lung injury: caspase-regulated apoptosis, pyroptosis, necroptosis, and PANoptosis

There has been abundant research on the variety of programmed cell death pathways. Apoptosis, pyroptosis, and necroptosis under the action of the caspase family are essential for the innate immune response. Caspases are classified into inflammatory caspase-1/4/5/11, apoptotic caspase-3/6/7, and caspase-2/8/9/10. Although necroptosis is not caspase-dependent to transmit cell death signals, it can cross-link with pyroptosis and apoptosis signals under the regulation of caspase-8. An increasing number of studies have reiterated the involvement of the caspase family in acute lung injuries caused by bacterial and viral infections, blood transfusion, and ventilation, which is influenced by noxious stimuli that activate or inhibit caspase engagement pathways, leading to subsequent lung injury. This article reviews the role of caspases implicated in diverse programmed cell death mechanisms in acute lung injury and the status of research on relevant inhibitors against essential target proteins of the described cell death mechanisms. The findings of this review may help in delineating novel therapeutic targets for acute lung injury.

Different types of cell death and their interactions in myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion (I/R) injury is a multifaceted process observed in patients with coronary artery disease when blood flow is restored to the heart tissue following ischemia-induced damage. Cardiomyocyte cell death, particularly through apoptosis, necroptosis, autophagy, pyroptosis, and ferroptosis, is pivotal in myocardial I/R injury. Preventing cell death during the process of I/R is vital for improving ischemic cardiomyopathy. These multiple forms of cell death can occur simultaneously, interact with each other, and contribute to the complexity of myocardial I/R injury. In this review, we aim to provide a comprehensive summary of the key molecular mechanisms and regulatory patterns involved in these five types of cell death in myocardial I/R injury. We will also discuss the crosstalk and intricate interactions among these mechanisms, highlighting the interplay between different types of cell death. Furthermore, we will explore specific molecules or targets that participate in different cell death pathways and elucidate their mechanisms of action. It is important to note that manipulating the molecules or targets involved in distinct cell death processes may have a significant impact on reducing myocardial I/R injury. By enhancing researchers' understanding of the mechanisms and interactions among different types of cell death in myocardial I/R injury, this review aims to pave the way for the development of novel interventions for cardio-protection in patients affected by myocardial I/R injury.

Nanomaterials evoke pyroptosis boosting cancer immunotherapy

Cancer immunotherapy is currently a very promising therapeutic strategy for treating tumors. However, its effectiveness is restricted by insufficient antigenicity and an immunosuppressive tumor microenvironment (ITME). Pyroptosis, a unique form of programmed cell death (PCD), causes cells to swell and rupture, releasing pro-inflammatory factors that can enhance immunogenicity and remodel the ITME. Nanomaterials, with their distinct advantages and different techniques, are increasingly popular, and nanomaterial-based delivery systems demonstrate significant potential to potentiate, enable, and augment pyroptosis. This review summarizes and discusses the emerging field of nanomaterials-induced pyroptosis, focusing on the mechanisms of nanomaterials-induced pyroptosis pathways and strategies to activate or enhance specific pyroptosis. Additionally, we provide perspectives on the development of this field, aiming to accelerate its further clinical transition.

NLRP3 inflammasome and gut microbiota-brain axis: a new perspective on white matter injury after intracerebral hemorrhage

ABSTRACT

Intracerebral hemorrhage is the most dangerous subtype of stroke, characterized by high mortality and morbidity rates, and frequently leads to significant secondary white matter injury. In recent decades, studies have revealed that gut microbiota can communicate bidirectionally with the brain through the gut microbiota-brain axis. This axis indicates that gut microbiota is closely related to the development and prognosis of intracerebral hemorrhage and its associated secondary white matter injury. The NACHT, LRR, and pyrin domain-containing protein 3 (NLRP3) inflammasome plays a crucial role in this context. This review summarizes the dysbiosis of gut microbiota following intracerebral hemorrhage and explores the mechanisms by which this imbalance may promote the activation of the NLRP3 inflammasome. These mechanisms include metabolic pathways (involving short-chain fatty acids, lipopolysaccharides, lactic acid, bile acids, trimethylamine-N-oxide, and tryptophan), neural pathways (such as the vagus nerve and sympathetic nerve), and immune pathways (involving microglia and T cells). We then discuss the relationship between the activated NLRP3 inflammasome and secondary white matter injury after intracerebral hemorrhage. The activation of the NLRP3 inflammasome can exacerbate secondary white matter injury by disrupting the blood-brain barrier, inducing neuroinflammation, and interfering with nerve regeneration. Finally, we outline potential treatment strategies for intracerebral hemorrhage and its secondary white matter injury. Our review highlights the critical role of the gut microbiota-brain axis and the NLRP3 inflammasome in white matter injury following intracerebral hemorrhage, paving the way for exploring potential therapeutic approaches.

NEK7 phosphorylation amplifies NLRP3 inflammasome activation downstream of potassium efflux and gasdermin D

The NLRP3 inflammasome plays a critical role in innate immunity and inflammatory diseases. NIMA-related kinase 7 (NEK7) is essential for inflammasome activation, and its interaction with NLRP3 is enhanced by K+ efflux. However, the mechanism by which K+ efflux promotes this interaction remains unknown. Here, we show that NEK7 is rapidly phosphorylated at threonine-190/191 by JNK1 downstream of K+ efflux and gasdermin D (GSDMD) after NLRP3 activation. NEK7 phosphorylation enhances the binding between NEK7 and NLRP3, which further promotes inflammasome assembly and activation. Mutant mice and macrophages in which Thr190 and Thr191 of Nek7 were replaced by valine exhibited impaired NEK7 phosphorylation, NLRP3 inflammasome activation, and IL-1β secretion. Thus, NEK7 phosphorylation is an important event that acts downstream of K+ efflux and GSDMD to further enhance NLRP3 inflammasome activation.

PRRSV-2 nsp2 Ignites NLRP3 inflammasome through IKKβ-dependent dispersed trans-Golgi network translocation

The NLRP3 inflammasome is a fundamental component of the innate immune system, yet its excessive activation is intricately associated with viral pathogenesis. Porcine reproductive and respiratory syndrome virus type 2 (PRRSV-2), belonging to the family Arteriviridae, triggers dysregulated cytokine release and interstitial pneumonia, which can quickly escalate to acute respiratory distress and death. However, a mechanistic understanding of PRRSV-2 progression remains unclear. Here, we screen that PRRSV-2 nsp2 activates the NLRP3 inflammasome, thereby instigating a state of hyperinflammation. Mechanistically, PRRSV-2 nsp2 interacts with the nucleotide-binding and oligomerization (NACHT) domain of NLRP3, augmenting IKKβ recruitment to driving NLRP3 translocation to the dispersed trans-Golgi network (dTGN) for oligomerization. This process facilitates ASC polymerization, culminating in the activation of the NLRP3 inflammasome. In addition, the IKKβ-dependent NLRP3 translocation to the dTGN is pivotal for pseudorabies virus (PRV) and encephalomyocarditis virus (EMCV)-induced inflammatory responses. Collectively, these results elucidate a novel mechanism of NLRP3 inflammasome activation during PRRSV-2 infection, providing valuable insights into PRRSV-2 pathogenesis.

Targeting programmed cell death in diabetic kidney disease: from molecular mechanisms to pharmacotherapy

Diabetic kidney disease (DKD), one of the most prevalent microvascular complications of diabetes, arises from dysregulated glucose and lipid metabolism induced by hyperglycemia, resulting in the deterioration of renal cells such as podocytes and tubular epithelial cells. Programmed cell death (PCD), comprising apoptosis, autophagy, ferroptosis, pyroptosis, and necroptosis, represents a spectrum of cell demise processes intricately governed by genetic mechanisms in vivo. Under physiological conditions, PCD facilitates the turnover of cellular populations and serves as a protective mechanism to eliminate impaired podocytes or tubular epithelial cells, thereby preserving renal tissue homeostasis amidst hyperglycemic stress. However, existing research predominantly elucidates individual modes of cell death, neglecting the intricate interplay and mutual modulation observed among various forms of PCD. In this comprehensive review, we delineate the diverse regulatory mechanisms governing PCD and elucidate the intricate crosstalk dynamics among distinct PCD pathways. Furthermore, we review recent advancements in understanding the pathogenesis of PCD and explore their implications in DKD. Additionally, we explore the potential of natural products derived primarily from botanical sources as therapeutic agents, highlighting their multifaceted effects on modulating PCD crosstalk, thereby proposing novel strategies for DKD treatment.

Advances in research on the impact and mechanisms of pathogenic microorganism infections on pyroptosis

Pyroptosis, also known as inflammatory necrosis, is a form of programmed cell death characterized by the activation of gasdermin proteins, leading to the formation of pores in the cell membrane, continuous cell swelling, and eventual membrane rupture. This process results in the release of intracellular contents, including pro-inflammatory cytokines like IL-1β and IL-18, which subsequently trigger a robust inflammatory response. This process is a crucial component of the body's innate immune response and plays a significant role in combating infections. There are four main pathways through which pathogenic microorganisms induce pyroptosis: the canonical inflammasome pathway, the non-canonical inflammasome pathway, the apoptosis-associated caspase-mediated pathway, and the granzyme-mediated pathway. This article provides a brief overview of the effects and mechanisms of pathogen infections on pyroptosis.

Pyroptosis in Endothelial Cells and Extracellular Vesicle Release in Atherosclerosis via NF-κB-Caspase-4/5-GSDM-D Pathway

Background: Pyroptosis, an inflammatory cell death, is involved in the progression of atherosclerosis. Pyroptosis in endothelial cells (ECs) and its underlying mechanisms in atherosclerosis are poorly understood. Here, we investigated the role of a caspase-4/5-NF-κB pathway in pyroptosis in palmitic acid (PA)-stimulated ECs and EVs as players in pyroptosis. Methods: Human umbilical vein endothelial cells (HUVECs) were cultured in an endothelial cell medium, treated with Ox-LDL, PA, caspase-4/5 inhibitor, NF-κB inhibitor, and sEV release inhibitor for 24 h, respectively. The cytotoxicity of PA was determined using an MTT assay, cell migration using a scratch-wound-healing assay, cell morphology using bright field microscopy, and lipid deposition using oil red O staining. The mRNA and protein expression of GSDM-D, CASP4, CASP5, NF-κB, NLRP3, IL-1β, and IL-18 were determined with RT-PCR and Western blot. Immunofluorescence was used to determine NLRP3 and ICAM-1 expressions. Extracellular vesicles (EVs) were isolated using an exosome isolation kit and were characterized by Western blot and scanning electron microscopy. Results: PA stimulation significantly changed the morphology of the HUVECs characterized by cell swelling, plasma membrane rupture, and increased LDH release, which are features of pyroptosis. PA significantly increased lipid accumulation and reduced cell migration. PA also triggered inflammation and endothelial dysfunction, as evidenced by NLRP3 activation, upregulation of ICAM-1 (endothelial activation marker), and pyroptotic markers (NLRP3, GSDM-D, IL-1β, IL-18). Inhibition of caspase-4/5 (Ac-FLTD-CMK) and NF-κB (trifluoroacetate salt (TFA)) resulted in a significant reduction in LDH release and expression of caspase-4/5, NF-κB, and gasdermin D (GSDM-D) in PA-treated HUVECs. Furthermore, GW4869, an exosome release inhibitor, markedly reduced LDH release in PA-stimulated HUVECs. EVs derived from PA-treated HUVECs exacerbated pyroptosis, as indicated by significantly increased LDH release and augmented expression of GSDM-D, NF-κB. Conclusions: The present study revealed that inflammatory, non-canonical caspase-4/5-NF-κB signaling may be one of the crucial mechanistic pathways associated with pyroptosis in ECs, and pyroptotic EVs facilitated pyroptosis in normal ECs during atherosclerosis.

A Dual Role of the Senescence Marker P16Ink4a in Liver Endothelial Cell Function

P16Ink4a is a well-established marker of senescence. Although P16Ink4a is expressed in endothelial cells, little is known about its function in these cells. Using isolated liver endothelial cells with silencing or overexpression of P16Ink4a, we show here that dependent on P16Ink4a levels, different pathways and functions are affected. High levels of P16Ink4a reduce proliferation and induce senescence, while low levels have the opposite effects. Only high P16Ink4a expression reduces in vitro angiogenesis. Expression profiling reveals an inflammatory phenotype upon silencing of P16Ink4a, while P16Ink4a overexpression is associated with a profile associated with DNA damage, repair and senescence. Low levels of P16Ink4a induce reactive oxygen species (ROS) generation and increase endothelial cell leakage. Collectively, P16Ink4a represents an "antagonistic pleiotropy" gene, which is, on the one hand, required to prevent ROS generation and endothelial damage and, on the other hand, inhibits angiogenesis through induction of senescence at high levels.

IL-18 biology in severe asthma

The role of interleukin-18 (IL-18) and inflammasomes in chronic inflammatory airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD), has garnered significant attention in recent years. This review aims to provide an overview of the current understanding of IL-18 biology, the associated signaling pathways, and the involvement of inflammasome complexes in airway diseases. We explore the multifaceted role of IL-18 in asthma pathophysiology, including its interactions with other cytokines and contributions to both T2 and non-T2 inflammation. Importantly, emerging evidence highlights IL-18 as a critical player in severe asthma, contributing to chronic airway inflammation, airway hyperresponsiveness (AHR), and mucus impaction. Furthermore, we discuss the emerging evidence of IL-18's involvement in autoimmunity and highlight potential therapeutic targets within the IL-18 and inflammasome pathways in severe asthma patients with evidence of infections and airway autoimmune responses. By synthesizing recent advancements and ongoing research, this review underscores the importance of IL-18 as a potential novel therapeutic target in the treatment of severe asthma and other related conditions.

Role of Pyroptosis in Endometrial Cancer and Its Therapeutic Regulation

Pyroptosis is an inflammatory cell death induced by inflammasomes that release several pro-inflammatory mediators such as interleukin-18 (IL-18) and interleukin-1β (IL-1β). Pyroptosis, a type of programmed cell death, has recently received increased interest both as a therapeutic and immunological mechanism. Numerous studies have provided substantial evidence supporting the involvement of inflammasomes and pyroptosis in a variety of pathological conditions including cancers, nerve damage, inflammatory diseases and metabolic conditions. Researchers have demonstrated that dysregulation of pyroptosis and inflammasomes contribute to the progression of endometriosis and gynecological malignancies. Current research also indicates that inflammasome and pyroptosis-dependent signaling pathways may further induce the progression of endometrial cancer (EC). More specifically, dysregulation of NLR family pyrin domain 3 (NLRP3) and caspase-1-dependent pyroptosis play a contributory role in the pathogenesis and development of EC. Therefore, pyroptosis-regulated protein gasdermin D (GSDMD) may be an independent prognostic biomarker for the detection of EC. This review presents the molecular mechanisms of pyroptosis-dependent signaling pathways and their contributory role and function in advancing EC. Moreover, this review offers new insights into potential future applications and innovative approaches in utilizing pyroptosis to develop effective anti-cancer therapies.

Caspase inhibitors: a review on recently patented compounds (2016-2023)

INTRODUCTION

Caspases are a family of protease enzymes that play a crucial role in apoptosis. Dysregulation of caspase activity has been implicated in various pathological conditions, making caspases an important focus of research in understanding cell death mechanisms and developing therapeutic strategies for diseases associated with abnormal apoptosis.

AREAS COVERED

It is a comprehensive review of caspase inhibitors that have been comprising recently granted patents from 2016 to 2023. It includes peptide and non-peptide caspase inhibitors with their application for different diseases.

EXPERT OPINION

This review categorizes and analyses recently patented caspase inhibitors on various diseases. Diseases linked to caspase dysregulation, including neurodegenerative disorders, and autoimmune conditions, are highlighted to accentuate the therapeutic relevance of the patented caspase inhibitors. This paper serves as a valuable resource for researchers, clinicians, and pharmaceutical developers seeking an up-to-date understanding of recently patented caspase inhibitors. The integration of recent patented compounds, structural insights, and mechanistic details provides a holistic view of the progress in caspase inhibitor research and its potential impact on addressing various diseases.

The Battle of LPS Clearance in Host Defense vs. Inflammatory Signaling

Lipopolysaccharide (LPS) in blood circulation causes endotoxemia and is linked to various disease conditions. Current treatments focus on preventing LPS from interacting with its receptor Toll-like receptor 4 (TLR4) and reducing inflammation. However, our body has a natural defense mechanism: reticuloendothelial cells in the liver rapidly degrade and inactivate much of the circulating LPS within minutes. But this LPS clearance mechanism is not perfect. Excessive LPS that escape this clearance mechanism cause systemic inflammatory damage through TLR4. Despite its importance, the role of reticuloendothelial cells in LPS elimination is not well-studied, especially regarding the specific cells, receptors, and mechanisms involved. This gap hampers the development of effective therapies for endotoxemia and related diseases. This review consolidates the current understanding of LPS clearance, narrates known and explores potential mechanisms, and discusses the relationship between LPS clearance and LPS signaling. It also aims to highlight key insights that can guide the development of strategies to reduce circulating LPS by way of bolstering host defense mechanisms. Ultimately, we seek to provide a foundation for future research that could lead to innovative approaches for enhancing the body's natural ability to clear LPS and thereby lower the risk of endotoxin-related inflammatory diseases, including sepsis.

Caspase-4 Has Potential Utility as a Colorectal Tissue Biomarker for Dysplasia and Early-Stage Cancer

Background and Aims

Colorectal cancer (CRC) is the second most deadly cancer globally. The rapidly rising incidence rate of CRC, coupled with increased diagnoses in individuals <50 years, indicates that early detection of CRC, and those at an increased risk of CRC development, is paramount to improve the survival rates of these patients. Here, we profile caspase-4 expression across 2 distinct CRC development pathways, sporadic CRC (sCRC) and inflammatory bowel disease-associated CRC (IBD-CRC), to examine its utility as a novel biomarker for CRC risk and diagnosis.

Methods

Tissue samples from patients with CRC, colonic polyps, IBD-CRC, and sCRC were assessed by immunohistochemistry for caspase-4 expression in epithelial and stromal compartments. RNAseq expression data for caspase-4 in CRC and normal tissue samples were mined from online databases.

Results

Epithelial caspase-4 expression is selectively elevated in CRC tumor tissue compared to adjacent normal tissue, where it is not expressed. In the sCRC pathway, caspase-4 is expressed in the epithelial and stromal tissue of all histological subtypes of colonic polyps, with a significant increase in epithelial expression from low-grade dysplasia to high-grade dysplasia progression. For the IBD-CRC pathway, caspase-4 epithelial expression was specifically upregulated in dysplastic and neoplastic tissue of IBD-CRC but was not expressed in normal or inflamed tissue.

Conclusion

This study demonstrates that epithelial caspase-4 is selectively expressed in colon tissue during the development of dysplasia. As such, epithelial caspase-4 represents a promising novel tissue biomarker for CRC risk and diagnosis.

Pyroptosis: A promising biomarker for predicting colorectal cancer prognosis and enhancing immunotherapy efficacy

In this editorial, we comment on the article by Zhu et al published in the recent issue of the World Journal of Clinical Oncology. We focus specifically on the characteristics and mechanisms of pyroptosis and the impact of changes in the tumor immune microenvironment (TIME) on cancer prognosis. Pyroptosis is a distinct form of programmed cell death; its occurrence can change the TIME and regulate the growth and spread of tumors and therefore is significantly correlated with cancer prognosis. Previous research has demonstrated that pyroptosis-related genes can be used in prognostic models for various types of cancer. These models enhance the mechanistic understanding of tumor evolution and serve as valuable guides for clinical treatment decision-making. Nevertheless, further studies are required to thoroughly understand the function of pyroptosis within the TIME and to assess its mode of action. Such studies should reveal new tumor therapeutic targets and more successful tumor immunotherapy strategies.

Ribonuclease inhibitor 1 emerges as a potential biomarker and modulates inflammation and iron homeostasis in sepsis

Sepsis, marked by organ dysfunction, necessitates reliable biomarkers. Ribonuclease inhibitor 1 (RNH1), a ribonuclease (RNase) inhibitor, emerged as a potential biomarker for acute kidney injury and mortality in thoracoabdominal aortic aneurysm patients. Our study investigates RNH1 dynamics in sepsis, its links to mortality and organ dysfunction, and the interplay with RNase 1 and RNase 5. Furthermore, we explore RNH1 as a therapeutic target in sepsis-related processes like inflammation, non-canonical inflammasome activation, and iron homeostasis. We showed that RNH1 levels are significantly higher in deceased patients compared to sepsis survivors and correlate with creatine kinase, aspartate and alanine transaminase, bilirubin, serum creatinine and RNase 5, but not RNase 1. RNH1 mitigated LPS-induced TNFα and RNase 5 secretion, and relative mRNA expression of ferroptosis-associated genes HMOX1, FTH1 and HAMP in PBMCs. Monocytes were identified as the predominant type of LPS-positive PBMCs. Exogenous RNH1 attenuated LPS-induced CASP5 expression, while increasing IL-1β secretion in PBMCs and THP-1 macrophages. As RNH1 has contradictory effects on inflammation and non-canonical inflammasome activation, its use as a therapeutic agent is limited. However, RNH1 levels may play a central role in iron homeostasis during sepsis, supporting our clinical observations. Hence, RNH1 shows promise as biomarkers for renal and hepatic dysfunction and hepatocyte injury, and may be useful in predicting the outcome of septic patients.

Metabolic Endotoxemia: From the Gut to Neurodegeneration

Metabolic endotoxemia is a severe health problem for residents in developed countries who follow a Western diet, disrupting intestinal microbiota and the whole organism's homeostasis. Although the effect of endotoxin on the human immune system is well known, its long-term impact on the human body, lasting many months or even years, is unknown. This is due to the difficulty of conducting in vitro and in vivo studies on the prolonged effect of endotoxin on the central nervous system. In this article, based on the available literature, we traced the path of endotoxin from the intestines to the blood through the intestinal epithelium and factors promoting the development of metabolic endotoxemia. The presence of endotoxin in the bloodstream and the inflammation it induces may contribute to lowering the blood-brain barrier, potentially allowing its penetration into the central nervous system; although, the theory is still controversial. Microglia, guarding the central nervous system, are the first line of defense and respond to endotoxin with activation, which may contribute to the development of neurodegenerative diseases. We traced the pro-inflammatory role of endotoxin in neurodegenerative diseases and its impact on the epigenetic regulation of microglial phenotypes.

Exacerbated Activation of the NLRP3 Inflammasome in the Placentas from Women Who Developed Chronic Venous Disease during Pregnancy

Chronic venous disease (CVD) comprises a spectrum of morphofunctional disorders affecting the venous system, affecting approximately 1 in 3 women during gestation. Emerging evidence highlights diverse maternofetal implications stemming from CVD, particularly impacting the placenta. While systemic inflammation has been associated with pregnancy-related CVD, preliminary findings suggest a potential link between this condition and exacerbated inflammation in the placental tissue. Inflammasomes are major orchestrators of immune responses and inflammation in different organs and systems. Notwithstanding the relevance of inflammasomes, specifically the NLRP3 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3)- which has been demonstrated in the placentas of women with different obstetric complications, the precise involvement of this component in the placentas of women with CVD remains to be explored. This study employs immunohistochemistry and real-time PCR (RT-qPCR) to examine the gene and protein expression of key components in both canonical and non-canonical pathways of the NLRP3 inflammasome (NLRP3, ASC-apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain-caspase 1, caspase 5, caspase 8, and interleukin 1β) within the placental tissue of women affected by CVD. Our findings reveal a substantial upregulation of these components in CVD-affected placentas, indicating a potential pathophysiological role of the NLRP3 inflammasome in the development of this condition. Subsequent investigations should focus on assessing translational interventions addressing this dysregulation in affected patient populations.

Caspase-5: Structure, Pro-Inflammatory Activity and Evolution

Caspase-5 is a protease that induces inflammation in response to lipopolysaccharide (LPS), a component of the cell envelope of Gram-negative bacteria. The expression level of the CASP5 gene is very low in the basal state, but strongly increases in the presence of LPS. Intracellular LPS binds to the caspase activation and recruitment domain (CARD) of caspase-5, leading to the formation of a non-canonical inflammasome. Subsequently, the catalytic domain of caspase-5 cleaves gasdermin D and thereby facilitates the formation of cell membrane pores through which pro-inflammatory cytokines of the interleukin-1 family are released. Caspase-4 is also able to form a non-canonical inflammasome upon binding to LPS, but its expression is less dependent on LPS than the expression of caspase-5. Caspase-4 and caspase-5 have evolved via the duplication of a single ancestral gene in a subclade of primates, including humans. Notably, the main biomedical model species, the mouse, has only one ortholog, namely caspase-11. Here, we review the structural features and the mechanisms of regulation that are important for the pro-inflammatory roles of caspase-5. We summarize the interspecies differences and the evolution of pro-inflammatory caspases in mammals and discuss the potential roles of caspase-5 in the defense against Gram-negative bacteria and in sepsis.

Characterization of the Apoptotic and Antimicrobial Activities of Two Initiator Caspases of Sea Cucumber Apostichopus japonicus

Caspase (CASP) is a protease family that plays a vital role in apoptosis, development, and immune response. Herein, we reported the identification and characterization of two CASPs, AjCASPX1 and AjCASPX2, from the sea cucumber Apostichopus japonicus, an important aquaculture species. AjCASPX1/2 share similar domain organizations with the vertebrate initiator caspases CASP2/9, including the CARD domain and the p20/p10 subunits with conserved functional motifs. However, compared with human CASP2/9, AjCASPX1/2 possess unique structural features in the linker region between p20 and p10. AjCASPX1, but not AjCASPX2, induced marked apoptosis of human cells by activating CASP3/7. The recombinant proteins of AjCASPX2 and the CARD domain of AjCASPX2 were able to bind to a wide range of bacteria, as well as bacterial cell wall components, and inhibit bacterial growth. AjCASPX1, when expressed in Escherichia coli, was able to kill the host bacteria. Under normal conditions, AjCASPX1 and AjCASPX2 expressions were most abundant in sea cucumber muscle and coelomocytes, respectively. After bacterial infection, both AjCASPX1 and AjCASPX2 expressions were significantly upregulated in sea cucumber tissues and cells. Together, these results indicated that AjCASPX1 and AjCASPX2 were initiator caspases with antimicrobial activity and likely functioned in apoptosis and immune defense against pathogen infection.

Hope for vascular cognitive impairment: Ac-YVAD-cmk as a novel treatment against white matter rarefaction

Vascular cognitive impairment (VCI) is the second leading cause of dementia with limited treatment options, characterised by cerebral hypoperfusion-induced white matter rarefaction (WMR). Subcortical VCI is the most common form of VCI, but the underlying reasons for region susceptibility remain elusive. Recent studies employing the bilateral cortical artery stenosis (BCAS) method demonstrate that various inflammasomes regulate white matter injury and blood-brain barrier dysfunction but whether caspase-1 inhibition will be beneficial remains unclear. To address this, we performed BCAS on C57/BL6 mice to study the effects of Ac-YVAD-cmk, a caspase-1 inhibitor, on the subcortical and cortical regions. Cerebral blood flow (CBF), WMR, neuroinflammation and the expression of tight junction-related proteins associated with blood-brain barrier integrity were assessed 15 days post BCAS. We observed that Ac-YVAD-cmk restored CBF, attenuated BCAS-induced WMR and restored subcortical myelin expression. Within the subcortical region, BCAS activated the NLRP3/caspase-1/interleukin-1beta axis only within the subcortical region, which was attenuated by Ac-YVAD-cmk. Although we observed that BCAS induced significant increases in VCAM-1 expression in both brain regions that were attenuated with Ac-YVAD-cmk, only ZO-1 and occludin were observed to be significantly altered in the subcortical region. Here we show that caspase-1 may contribute to subcortical regional susceptibility in a mouse model of VCI. In addition, our results support further investigations into the potential of Ac-YVAD-cmk as a novel treatment strategy against subcortical VCI and other conditions exhibiting cerebral hypoperfusion-induced WMR.

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.

The role of the NLRP3 inflammasome and pyroptosis in cardiovascular diseases

An intense, stereotyped inflammatory response occurs in response to ischaemic and non-ischaemic injury to the myocardium. The NACHT, LRR and PYD domains-containing protein 3 (NLRP3) inflammasome is a finely regulated macromolecular protein complex that senses the injury and triggers and amplifies the inflammatory response by activation of caspase 1; cleavage of pro-inflammatory cytokines, such as pro-IL-1β and pro-IL-18, to their mature forms; and induction of inflammatory cell death (pyroptosis). Inhibitors of the NLRP3 inflammasome and blockers of IL-1β and IL-18 activity have been shown to reduce injury to the myocardium and pericardium, favour resolution of the inflammation and preserve cardiac function. In this Review, we discuss the components of the NLRP3 inflammasome and how it is formed and activated in various ischaemic and non-ischaemic cardiac pathologies (acute myocardial infarction, cardiac dysfunction and remodelling, atherothrombosis, myocarditis and pericarditis, cardiotoxicity and cardiac sarcoidosis). We also summarize current preclinical and clinical evidence from studies of agents that target the NLRP3 inflammasome and related cytokines.

Inflammasome diversity: exploring novel frontiers in the innate immune response

Pathogens elicit complex mammalian immune responses by activating multiple sensors within inflammasomes, which recognize diverse pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs). This simultaneous activation induces the formation of protein complexes referred to as multiple inflammasomes, that orchestrate a spectrum of programmed cell death pathways, including pyroptosis, apoptosis, and necroptosis. This concept is crucial for comprehending the complexity of the innate immune system's response to diverse pathogens and its implications for various diseases. Novel contributions here include emphasizing simultaneous sensor activation by pathogens, proposing the existence of multiple inflammasome complexes, and advocating for further exploration of their structural basis. Understanding these mechanisms may offer insights into disease pathogenesis, paving the way for potential therapeutic interventions targeting inflammasome-mediated immune responses.

"How to Release or Not Release, That Is the Question." A Review of Interleukin-1 Cellular Release Mechanisms in Vascular Inflammation

Cardiovascular disease remains the leading cause of death worldwide, characterized by atherosclerotic activity within large and medium-sized arteries. Inflammation has been shown to be a primary driver of atherosclerotic plaque formation, with interleukin-1 (IL-1) having a principal role. This review focuses on the current state of knowledge of molecular mechanisms of IL-1 release from cells in atherosclerotic plaques. A more in-depth understanding of the process of IL-1's release into the vascular environment is necessary for the treatment of inflammatory disease processes, as the current selection of medicines being used primarily target IL-1 after it has been released. IL-1 is secreted by several heterogenous mechanisms, some of which are cell type-specific and could provide further specialized targets for therapeutic intervention. A major unmet challenge is to understand the mechanism before and leading to IL-1 release, especially by cells in atherosclerotic plaques, including endothelial cells, vascular smooth muscle cells, and macrophages. Data so far indicate a heterogeneity of IL-1 release mechanisms that vary according to cell type and are stimulus-dependent. Unraveling this complexity may reveal new targets to block excess vascular inflammation.

MicroRNA-mediated epigenetic regulation of inflammasomes in inflammatory responses and immunopathologies

Inflammation represents the first-line defense mechanism of the host against pathogens and cellular stress. One of the most critical inflammatory responses is characterized by the activation of inflammasomes, intracellular multiprotein complexes that induce inflammatory signaling pathways in response to various pathogen-associated molecular patterns or danger-associated molecular patterns under physiological and pathological conditions. Inflammasomes are tightly regulated in normal cells, and dysregulation of these complexes is observed in various pathological conditions, especially inflammatory diseases and cancers. Epigenetic regulation has been suggested as a key mechanism in modulating inflammasome activity, and microRNAs (miRNAs) have been implicated in the post-transcriptional regulation of inflammasomes. Therefore, miRNA-mediated epigenetic regulation of inflammasomes in pathological conditions has received considerable attention, and current strategies for targeting inflammasomes have been shown to be effective in the treatment of diseases associated with inflammasome activation. This review summarizes recent studies suggesting the roles of miRNAs in the epigenetic control of inflammasomes and highlights the potential of miRNAs as a therapeutic tool for treating human diseases.

Emerging role of exosomes in ulcerative colitis: Targeting NOD-like receptor family pyrin domain containing 3 inflammasome

Ulcerative colitis (UC) is a chronic recurrent inflammatory bowel disease. Despite ongoing advances in our understanding of UC, its pathogenesis is yet unelucidated, underscoring the urgent need for novel treatment strategies for patients with UC. Exosomes are nanoscale membrane particles that mediate intercellular communication by carrying various bioactive molecules, such as proteins, RNAs, DNA, and metabolites. The NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome is a cytosolic tripartite protein complex whose activation induces the maturation and secretion of proinflammatory cytokines interleukin-1β (IL-1β) and IL-18, triggering the inflammatory response to a pathogenic agent or injury. Growing evidence suggests that exosomes are new modulators of the NLRP3 inflammasome, with vital roles in the pathological process of UC. Here, recent evidence is reviewed on the role of exosomes and NLRP3 inflammasome in UC. First, the dual role of exosomes on NLRP3 inflammasome and the effect of NLRP3 inflammasome on exosome secretion are summarized. Finally, an outlook on the directions of exosome-NLRP3 inflammasome crosstalk research in the context of UC is proposed and areas of further research on this topic are highlighted.

Roles of the Caspase-11 Non-Canonical Inflammasome in Rheumatic Diseases

Inflammasomes are intracellular multiprotein complexes that activate inflammatory signaling pathways. Inflammasomes comprise two major classes: canonical inflammasomes, which were discovered first and are activated in response to a variety of pathogen-associated molecular patterns (PAMPs) and danger-associated molecular patterns (DAMPs), and non-canonical inflammasomes, which were discovered recently and are only activated in response to intracellular lipopolysaccharide (LPS). Although a larger number of studies have successfully demonstrated that canonical inflammasomes, particularly the NLRP3 inflammasome, play roles in various rheumatic diseases, including rheumatoid arthritis (RA), infectious arthritis (IR), gouty arthritis (GA), osteoarthritis (OA), systemic lupus erythematosus (SLE), psoriatic arthritis (PA), ankylosing spondylitis (AS), and Sjögren's syndrome (SjS), the regulatory roles of non-canonical inflammasomes, such as mouse caspase-11 and human caspase-4 non-canonical inflammasomes, in these diseases are still largely unknown. Interestingly, an increasing number of studies have reported possible roles for non-canonical inflammasomes in the pathogenesis of various mouse models of rheumatic disease. This review comprehensively summarizes and discusses recent emerging studies demonstrating the regulatory roles of non-canonical inflammasomes, particularly focusing on the caspase-11 non-canonical inflammasome, in the pathogenesis and progression of various types of rheumatic diseases and provides new insights into strategies for developing potential therapeutics to prevent and treat rheumatic diseases as well as associated diseases by targeting non-canonical inflammasomes.

Harnessing the potential of CD40 agonism in cancer therapy

CD40 is a member of the tumor necrosis factor (TNF) receptor superfamily of receptors expressed on a variety of cell types. The CD40-CD40L interaction gives rise to many immune events, including the licensing of dendritic cells to activate CD8+ effector T cells, as well as the facilitation of B cell activation, proliferation, and differentiation. In malignant cells, the expression of CD40 varies among cancer types, mediating cellular proliferation, apoptosis, survival and the secretion of cytokines and chemokines. Agonistic human anti-CD40 antibodies are emerging as an option for cancer treatment, and early-phase clinical trials explored its monotherapy or combination with radiotherapy, chemotherapy, immune checkpoint blockade, and other immunomodulatory approaches. In this review, we present the current understanding of the mechanism of action for CD40, along with results from the clinical development of agonistic human CD40 antibodies in cancer treatment (selicrelumab, CDX-1140, APX005M, mitazalimab, 2141-V11, SEA-CD40, LVGN7409, and bispecific antibodies). This review also examines the safety profile of CD40 agonists in both preclinical and clinical settings, highlighting optimized dosage levels, potential adverse effects, and strategies to mitigate them.

Non-apoptotic cell death programs in cervical cancer with an emphasis on ferroptosis

BACKGROUND

Cervical cancer, a pernicious gynecological malignancy, causes the mortality of hundreds of thousands of females worldwide. Despite a considerable decline in mortality, the surging incidence rate among younger women has raised serious concerns. Immortality is the most important characteristic of tumor cells, hence the carcinogenesis of cervical cancer cells pivotally requires compromising with cell death mechanisms.

METHODS

The current study comprehensively reviewed the mechanisms of non-apoptotic cell death programs to provide possible disease management strategies.

RESULTS

Comprehensive evidence has stated that focusing on necroptosis, pyroptosis, and autophagy for disease management is associated with significant limitations such as insufficient understanding, contradictory functions, dependence on disease stage, and complexity of intracellular pathways. However, ferroptosis represents a predictable role in cervix carcinogenesis, and ferroptosis-related genes demonstrate a remarkable correlation with patient survival and clinical outcomes.

CONCLUSION

Ferroptosis may be an appropriate option for disease management strategies from predicting prognosis to treatment.

Effect of O antigen glycosyl isomerase gene mutation on biological property and pathogenicity of Burkholderia pseudomallei strain BPC006

Burkholderia pseudomallei, an intracellular pathogen, is responsible for melioidosis, a zoonotic disease. Its pathogenesis involves several virulence factors, among which lipopolysaccharide (LPS) plays a crucial role. Our research reveals that the O antigen present within the LPS significantly regulates the host immune response. In a previous study, we obtained a B. pseudomallei mutant strain ΔwbiI. Here, the purification of LPS from ΔwbiI and a gas chromatography-mass spectrometry (GC-MS) analysis were conducted. The results confirmed the absence of specific sugar 6-deoxy-Talp, which is a typical component of the O antigen in the wild type B. pseudomallei. Our findings underscore the potent impact the O antigen exerts on the virulence of B. pseudomallei. The ΔwbiI strain displayed significantly increased invasiveness and cytotoxicity in vitro. This enhanced cytotoxicity seems to be related to the exposure of lipid A and an increased cell membrane hydrophobicity resulting from the deletion of the O antigen. Additionally, in mouse models, the ΔwbiI strain resulted in a heightened host lethality and an excessive inflammatory response in mice. These findings indicate that the O-antigenic polysaccharide moiety of B. pseudomallei plays a role in its pathogenicity in vitro and in vivo.

Characterization of caspase gene family in Sebastes schlegelii and their expression profiles under Aeromonas salmonicida and Vibrio anguillarum infection

The caspase, functioning as a proteinase, plays a crucial role in eukaryotic cell apoptosis, regulation of apoptosis, cellular growth, differentiation, and immunity. The identification of caspase gene family in Sebastes schlegelii is of great help to understand its antimicrobial research. In S. schlegelii, we totally identified nine caspase genes, including four apoptosis initiator caspases (caspase 2, caspase 8, caspase 9 and caspase 10), four apoptosis executioners (caspase 3a, caspase 3b, caspase 6, and caspase 7) and one inflammatory executioner (caspase 1). The duplication of caspase 3 genes on chr3 and chr8 may have been facilitated by whole genome duplication (WGD) events or other complex evolutionary processes. In general, the number of caspase genes relatively conserved in high vertebrates, while exhibiting variation in teleosts. Furthermore, syntenic analysis and phylogenetic relationships analysis supported the correct classification of these caspase gene family in S. schlegelii, especially for genes with duplicated copies. Additionally, the expression patterns of these caspase genes in different tissues of S. schlegelii under healthy conditions were assessed. The results revealed that the expression levels of most caspase genes were significantly elevated in the intestine, spleen, and liver. To further investigate the potential immune functions of these caspase genes in S. schlegelii, we challenged individuals with A. salmonicida and V. anguillarum, respectively. After infection with A. salmonicida, the expression levels of caspase 1 in the liver and spleen of S. schlegelii remained consistently elevated throughout the infection time points. The expression levels of most caspase family members in the intestine exhibited significant divergence following V. anguillarum infection. This study provides a comprehensive understanding of the caspase gene families in S. schlegelii, thereby establishing a solid foundation for further investigations into the functional roles of these caspase genes.

Recent advances in understanding the human host immune response in tuberculous meningitis

Tuberculous meningitis (TBM), the most severe form of tuberculosis, causes death in approximately 25% cases despite antibiotic therapy, and half of survivors are left with neurological disability. Mortality and morbidity are contributed to by a dysregulated immune response, and adjunctive host-directed therapies are required to modulate this response and improve outcomes. Developing such therapies relies on improved understanding of the host immune response to TBM. The historical challenges in TBM research of limited in vivo and in vitro models have been partially overcome by recent developments in proteomics, transcriptomics, and metabolomics, and the use of these technologies in nested substudies of large clinical trials. We review the current understanding of the human immune response in TBM. We begin with M. tuberculosis entry into the central nervous system (CNS), microglial infection and blood-brain and other CNS barrier dysfunction. We then outline the innate response, including the early cytokine response, role of canonical and non-canonical inflammasomes, eicosanoids and specialised pro-resolving mediators. Next, we review the adaptive response including T cells, microRNAs and B cells, followed by the role of the glutamate-GABA neurotransmitter cycle and the tryptophan pathway. We discuss host genetic immune factors, differences between adults and children, paradoxical reaction, and the impact of HIV-1 co-infection including immune reconstitution inflammatory syndrome. Promising immunomodulatory therapies, research gaps, ongoing challenges and future paths are discussed.

Nanomaterials for Disease Treatment by Modulating the Pyroptosis Pathway

Pyroptosis differs significantly from apoptosis and cell necrosis as an alternative mode of programmed cell death. Its occurrence is mediated by the gasdermin protein, leading to characteristic outcomes including cell swelling, membrane perforation, and release of cell contents. Research underscores the role of pyroptosis in the etiology and progression of many diseases, making it a focus of research intervention as scientists explore ways to regulate pyroptosis pathways in disease management. Despite numerous reviews detailing the relationship between pyroptosis and disease mechanisms, few delve into recent advancements in nanomaterials as a mechanism for modulating the pyroptosis pathway to mitigate disease effects. Therefore, there is an urgent need to fill this gap and elucidate the path for the use of this promising technology in the field of disease treatment. This review article delves into recent developments in nanomaterials for disease management through pyroptosis modulation, details the mechanisms by which drugs interact with pyroptosis pathways, and highlights the promise that nanomaterial research holds in driving forward disease treatment.

Food-derived peptides as novel therapeutic strategies for NLRP3 inflammasome-related diseases: a systematic review

NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3), a member of the nucleotide-binding domain (NOD) and leucine-rich repeat sequence (LRR) protein (NLR) family, plays an essential role in the inflammation initiation and inflammatory mediator secretion, and thus is also associated with many disease progressions. Food-derived bioactive peptides (FDBP) exhibit excellent anti-inflammatory activity in both in vivo and in vitro models. They are encrypted in plant, meat, and milk proteins and can be released under enzymatic hydrolysis or fermentation conditions, thereby hindering the progression of hyperuricemia, inflammatory bowel disease, chronic liver disease, neurological disorders, lung injury and periodontitis by inactivating the NLRP3. However, there is a lack of systematic review around FDBP, NLRP3, and NLRP3-related diseases. Therefore, this review summarized FDBP that exert inhibiting effects on NLRP3 inflammasome from different protein sources and detailed their preparation and purification methods. Additionally, this paper also compiled the possible inhibitory mechanisms of FDBP on NLRP3 inflammasomes and its regulatory role in NLRP3 inflammasome-related diseases. Finally, the progress of cutting-edge technologies, including nanoparticle, computer-aided screening strategy and recombinant DNA technology, in the acquisition or encapsulation of NLRP3 inhibitory FDBP was discussed. This review provides a scientific basis for understanding the anti-inflammatory mechanism of FDBP through the regulation of the NLRP3 inflammasome and also provides guidance for the development of therapeutic adjuvants or functional foods enriched with these FDBP.

ASC/inflammasome-independent pyroptosis in ovarian cancer cells through translational augmentation of caspase-1

Canonical pyroptosis is type of programmed cell death depending on active caspase-1, and the inflammasome carries out caspase-1 activation. Here, we showed that docosahexaenoic acid (DHA) induced ovarian cancer cell deaths in caspase-1-dependent manner. DHA increased caspase-1 activity and led to interleukin-1β secretion and gasdermin D cleavage while disulfiram inhibited DHA-induced cell death, suggesting that DHA triggered pyroptosis. Intriguingly, ASC, the molecule recruiting caspase-1 to inflammasome for activation, was dispensable for DHA-induced pyroptosis. Instead, we observed remarkable elevation in caspase-1 abundance concurrent with the activation of caspase-1 in DHA-treated cells. As ectopically overexpressing caspase-1 resulted in robust amount of active caspase-1, we reason that DHA activates caspase-1 and pyroptosis through the generation of excessive amount of caspase-1 protein. Mechanistically, DHA increased caspase-1 by specifically accelerating caspase-1 protein synthesis via the p38MAPK/Mnk1 signaling pathway. We have uncovered an unknown pyroptosis mechanism in which caspase-1-dependent pyroptosis can occur without the participation of ASC/inflammasome.

Loss of CFTR function in macrophages alters the cell transcriptional program and delays lung resolution of inflammation

Cystic fibrosis (CF) is an autosomal recessive genetic disorder caused by mutations in the CF Transmembrane-conductance Regulator (CFTR) gene. The most severe pathologies of CF occur in the lung, manifesting as chronic bacterial infection, persistent neutrophilic inflammation, and mucopurulent airway obstruction. Despite increasing knowledge of the CF primary defect and the resulting clinical sequelae, the relationship between the CFTR loss of function and the neutrophilic inflammation remains incompletely understood. Here, we report that loss of CFTR function in macrophages causes extended lung inflammation. After intratracheal inoculation with Pseudomonas aeruginosa, mice with a macrophage-specific Cftr-knockout (Mac-CF) were able to mount an effective host defense to clear the bacterial infection. However, three days post-inoculation, Mac-CF lungs demonstrated significantly more neutrophil infiltration and higher levels of inflammatory cytokines, suggesting that Mac-CF mice had a slower resolution of inflammation. Single-cell RNA sequencing revealed that absence of CFTR in the macrophages altered the cell transcriptional program, affecting the cell inflammatory and immune responses, antioxidant system, and mitochondrial respiration. Thus, loss of CFTR function in macrophages influences cell homeostasis, leading to a dysregulated cellular response to infection that may exacerbate CF lung disease.

Placentas from Women with Late-Onset Preeclampsia Exhibit Increased Expression of the NLRP3 Inflammasome Machinery

Pre-eclampsia is a harmful and potentially lethal medical condition during pregnancy clinically diagnosed by hypertension and commonly accompanied by proteinuria and multiorgan affections. According to the time of diagnosis, it is differentiated between early-onset (EO-PE) and late-onset preeclampsia (LO-PE). Despite being less dangerous and presenting distinct pathophysiological signatures, LO-PE has a greater prevalence than EO-PE, both having significant consequences on the placenta. Previous works have evidenced that exacerbated inflammation in this organ might play a potential pathogenic role in the development of pre-eclampsia, and there is some preliminary evidence that the hyperactivation of inflammasomes can be related to the altered immunoinflammatory responses observed in the placentas of these patients. However, the precise role of inflammasomes in the placentas of women with LO-PE remains to be fully understood. In this work, we have studied the gene and protein expression of the main components related to the canonical and non-canonical pathways of the inflammasome NLRP3 (NLRP3, ASC, caspase 1, caspase 5, caspase 8, interleukin 1β, and interleukin 18) in the placental tissue of women with LO-PE. Our results show a marked increase in all these components in the placentas of women who have undergone LO-PE, suggesting that NLRP3 inflammasome plays a potentially pathophysiological role in the development of this entity. Future works should aim to evaluate possible translational approaches to this dysregulation in these patients.

Inflammasome pathway in kidney transplantation

Kidney transplantation is the best available renal replacement therapy for patients with end-stage kidney disease and is associated with better quality of life and patient survival compared with dialysis. However, despite the significant technical and pharmaceutical advances in this field, kidney transplant recipients are still characterized by reduced long-term graft survival. In fact, almost half of the patients lose their allograft after 15-20 years. Most of the conditions leading to graft loss are triggered by the activation of a large immune-inflammatory machinery. In this context, several inflammatory markers have been identified, and the deregulation of the inflammasome (NLRP3, NLRP1, NLRC4, AIM2), a multiprotein complex activated by either whole pathogens (including fungi, bacteria, and viruses) or host-derived molecules, seems to play a pivotal pathogenetic role. However, the biological mechanisms leading to inflammasome activation in patients developing post-transplant complications (including, ischemia-reperfusion injury, rejections, infections) are still largely unrecognized, and only a few research reports, reviewed in this manuscript, have addressed the association between abnormal activation of this pathway and the onset/development of major clinical effects. Finally, the regulation of the inflammasome machinery could represent in future a valuable therapeutic target in kidney transplantation.

Inhibition of Caspase-1-mediated pyroptosis promotes osteogenic differentiation, offering a therapeutic target for osteoporosis

BACKGROUND

Pyroptosis, an emerging inflammatory form of cell death, has been previously demonstrated to stimulate a massive inflammatory response, thus hindering the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). Nevertheless, the impact of pyroptosis in thwarting osteogenic differentiation and exacerbating the advancement of osteoporosis (OP) remains enigmatic.

METHODS

We evaluated the expression levels of pyroptosis-associated indicators, including NOD-like receptor family pyrin domain-containing protein 3 (NLRP3), CASPASE-1, IL-1β, and IL-18, in specimens obtained from femoral heads of OP patients, as well as in an ovariectomy-induced mouse model of OP. Subsequently, the precise roles of pyroptosis in osteogenic differentiation were investigated using bioinformatics analysis, alongside morphological and biochemical assessments.

RESULTS

The pivotal pyroptotic proteins, including NLRP3, Caspase-1, IL-1β, and IL-18, exhibited significant upregulation within the bone tissue samples of clinical OP cases, as well as in the femoral tissues of ovariectomy (OVX)-induced mouse OP model, displaying a negatively associated with compromised osteogenic capacity, as represented by lessened bone mass, suppressed expression of osteogenic proteins such as Runt-related transcription factor 2 (RUNX2), Alkaline phosphatase (ALP), Osterix (OSX), and Osteopontin (OPN), and increased lipid droplets. Moreover, bioinformatics analysis substantiated shared gene expression patterns between pyroptosis and OP pathology, encompassing NLRP3, Caspase-1, IL-1β, IL-18, etc. Furthermore, our in vitro investigation using ST2 cells revealed that dexamethasone treatment prominently induced pyroptosis while impeding osteogenic differentiation. Notably, gene silencing of Caspase-1 effectively counteracted the inhibitory effects of dexamethasone on osteogenic differentiation, as manifested by increased ALP activity and enhanced expression of RUNX2, ALP, OSX, and OPN.

CONCLUSION

Our findings unequivocally underscore that inhibition of Caspase-1-mediated pyroptosis promotes osteogenic differentiation, providing a promising therapeutic target for managing OP.

Recent advances in natural compounds inducing non-apoptotic cell death for anticancer drug resistance

The induction of cell death is recognized as a potent strategy for cancer treatment. Apoptosis is an extensively studied form of cell death, and multiple anticancer drugs exert their therapeutic effects by inducing it. Nonetheless, apoptosis evasion is a hallmark of cancer, rendering cancer cells resistant to chemotherapy drugs. Consequently, there is a growing interest in exploring novel non-apoptotic forms of cell death, such as ferroptosis, necroptosis, pyroptosis, and paraptosis. Natural compounds with anticancer properties have garnered significant attention due to their advantages, including a reduced risk of drug resistance. Over the past two decades, numerous natural compounds have been discovered to exert anticancer and anti-resistance effects by triggering these four non-apoptotic cell death mechanisms. This review primarily focuses on these four non-apoptotic cell death mechanisms and their recent advancements in overcoming drug resistance in cancer treatment. Meanwhile, it highlights the role of natural compounds in effectively addressing cancer drug resistance through the induction of these forms of non-apoptotic cell death.