Critical role for calcium mobilization in activation of the NLRP3 inflammasome

Pyroptosis, ferroptosis, and autophagy in spinal cord injury: regulatory mechanisms and therapeutic targets

Regulated cell death is a form of cell death that is actively controlled by biomolecules. Several studies have shown that regulated cell death plays a key role after spinal cord injury. Pyroptosis and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal cords. Autophagy, a complex form of cell death that is interconnected with various regulated cell death mechanisms, has garnered significant attention in the study of spinal cord injury. This injury triggers not only cell death but also cellular survival responses. Multiple signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis, ferroptosis, and autophagy. Therefore, this review aims to comprehensively examine the mechanisms underlying regulated cell deaths, the signaling pathways that modulate these mechanisms, and the potential therapeutic targets for spinal cord injury. Our analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord injury. Moreover, a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury.

Research progress on sepsis-associated encephalopathy by inhibiting pyroptosis

Sepsis is a life-threatening condition characterized by multiple organ dysfunction syndrome resulted from dysregulated host responses to infection. Sepsis-associated encephalopathy (SAE) is one of the most common symptoms of acute-phase sepsis, with nearly 70 % of patients with sepsis ultimately developing SAE. Pyroptosis represents a type of cell death that is initiated by inflammation. This cell death type is associated with various infectious and noninfectious diseases. The gasdermin family proteins are crucial cell death executors and critical components in regulating the canonical pyroptosis pathway in microglia. In this review, we summarize the inhibitory effects of several drugs and genes on the pyroptosis pathway. Our findings suggest that several drugs (puerarin, VX765, HC067047, dexpramipexole, and Danhong injection), erbin gene, and TRIM45 knockdown improve SAE by suppressing the canonical pathway of NLRP3/caspase-1/gasdermin D-mediated pyroptosis. Therefore, they have significant importance in terms of brain protection. Moreover, we review the relevant literature published in recent years and summarize the research status and development prospects in this field to provide a basis for subsequent related research.

Mitochondrial Dysfunction is a Crucial Immune Checkpoint for Neuroinflammation and Neurodegeneration: mtDAMPs in Focus

Neuroinflammation is a pivotal factor in the progression of both age-related and acute neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, multiple sclerosis, and stroke. Mitochondria, essential for neuronal health due to their roles in energy production, calcium buffering, and oxidative stress regulation, become increasingly susceptible to dysfunction under conditions of metabolic stress, aging, or injury. Impaired mitophagy in aged or injured neurons leads to the accumulation of dysfunctional mitochondria, which release mitochondrial-derived damage-associated molecular patterns (mtDAMPs). These mtDAMPs act as immune checkpoints, activating pattern recognition receptors (PRRs) and triggering innate immune signaling pathways. This activation initiates inflammatory responses in neurons and brain-resident immune cells, releasing cytokines and chemokines that damage adjacent healthy neurons and recruit peripheral immune cells, further amplifying neuroinflammation and neurodegeneration. Long-term mitochondrial dysfunction perpetuates a chronic inflammatory state, exacerbating neuronal injury and contributing additional immunogenic components to the extracellular environment. Emerging evidence highlights the critical role of mtDAMPs in initiating and sustaining neuroinflammation, with circulating levels of these molecules potentially serving as biomarkers for disease progression. This review explores the mechanisms of mtDAMP release due to mitochondrial dysfunction, their interaction with PRRs, and the subsequent activation of inflammatory pathways. We also discuss the role of mtDAMP-triggered innate immune responses in exacerbating both acute and chronic neuroinflammation and neurodegeneration. Targeting dysfunctional mitochondria and mtDAMPs with pharmacological agents presents a promising strategy for mitigating the initiation and progression of neuropathological conditions.

Disseminated Intravascular Coagulopathy and Persistent Inflammation, Immunosuppression, and Catabolism Syndrome: Pathophysiology, shared pathways, and clinical implications

BACKGROUND

Disseminated Intravascular Coagulopathy (DIC) and Persistent Inflammation, Immunosuppression, and Catabolism Syndrome (PICS) are critical care syndromes that frequently coexist in critically ill patients, but mechanisms underlying their shared pathways are not well understood.

OBJECTIVE

This review discusses the pathophysiology of DIC and PICS and explores the shared mechanisms behind DIC and PICS and their implications for clinical management.

FINDINGS

DIC and PICS share a common pathophysiological foundation of endothelial dysfunction, coagulation dysregulation, and inflammation, leading to a vicious cycle of microvascular injury and systemic inflammation, culminating in organ dysfunction. DIC has also been identified as an independent risk factor for PICS. Anticoagulation therapies such as antithrombin, recombinant human soluble thrombomodulin (rhTM), and heparin attenuates inflammation, a mechanism underlying both syndromes, thereby improving outcomes in PICS.

CONCLUSION

DIC and PICS share critical pathophysiological pathways that exacerbate outcomes in critically ill patients. Recognizing these interconnections is essential for developing targeted therapies. Standardizing PICS definitions and advancing research to clarify mechanisms, interplay, and causality between DIC and PICS are crucial next steps.

Mechanistic Insights into T-2 Toxin-Induced Thymic Epithelial Cell Injury and Immunotoxicity via the ROS-NF-κB-NLRP3 Signaling Axis

Thymic epithelial cells (TECs) are critical for thymic structure and function, yet the impact of T-2 toxin (T-2) on TECs and related molecular pathways remains unclear. This study sheds light on the mechanisms of T-2-induced TEC damage, focusing on the ROS-NF-κB-NLRP3 signaling axis. The in vivo and in vitro analyses suggest that T-2 induces TEC injury through ROS-driven NLRP3 inflammasome activation, NF-κB signaling, inflammation, and apoptosis. Molecular docking analysis verified the binding of T-2 to critical components involved in oxidative stress, inflammatory signaling pathways, and apoptosis. These findings were further supported by therapeutic interventions targeting ROS and NLRP3. N-acetylcysteine (NAC) effectively reduced ROS levels, suppressed NF-κB signaling, inhibited NLRP3 activation, and mitigated inflammation and apoptosis, effects mirrored by the NLRP3 inhibitor MCC950, emphasizing the critical role of ROS-mediated NLRP3 inflammasome activation through NF-κB signaling in T-2-induced TEC damage. Concurrently, inhibition of the NF-κB signaling further suppressed ROS levels, NLRP3 inflammasome activation, and apoptosis in MTEC1 cells, emphasizing the pivotal function of the ROS-NF-κB-NLRP3 axis in the pathogenesis of T-2-induced thymic injury. Our study offers an in-depth insight into the mechanisms driving T-2-induced immunotoxicity and identifies potential therapeutic strategies targeting these pathways to mitigate thymic injury and preserve immune function.

Deciphering the NLRP3 inflammasome in diabetic encephalopathy: Molecular insights and emerging therapeutic targets

Diabetic encephalopathy (DE) is a neurological complication characterized by neuroinflammation, cognitive impairment, and memory decline, with its pathogenesis closely linked to the activation of the NLRP3 inflammasome. As a central regulator of the innate immune system, the NLRP3 inflammasome plays a pivotal role in DE progression by mediating neuroinflammation, pyroptosis, mitochondrial dysfunction, oxidative stress, endoplasmic reticulum (ER) stress, and microglial polarization. This review systematically explores the molecular mechanisms by which the NLRP3 inflammasome contributes to DE, focusing on its role in neuroinflammatory cascades and neuronal damage, as well as the diabetes-associated physiological changes that exacerbate DE pathogenesis. Furthermore, we summarize emerging therapeutic strategies targeting the NLRP3 inflammasome, including small-molecule inhibitors and bioactive compounds derived from traditional herbal medicine, highlighting their potential for DE treatment. These findings not only advance our understanding of DE but also provide a foundation for developing NLRP3-targeted pharmacological interventions.

Inflammasomes: novel therapeutic targets for metabolic syndrome?

Chronic inflammation is a hallmark for Metabolic Syndrome (MetS). It is also one of the most important risk factors for insulin resistance and metabolic disorders. Inflammasomes, which are intracellular multiprotein complexes within the innate immune system, regulate the production and maturation of pro-inflammatory cytokines including interleukin-1β (IL-1β) and IL-18 upon sensing pathogens or danger signals in the cytosol. A growing body of evidence indicates that inflammasomes play a pivotal role in the pathophysiology and progression of metabolic diseases, as deficiency in the key component of inflammasomes protects mice from high fat diet induced obesity and insulin resistance. Thus, in this review, we will summarize the role of inflammasomes in MetS and how to treat MetS by targeting inflammasomes. This may provide novel insights and therapeutic targets for treating metabolic disorders.

NLRP3 inflammasome: structure, mechanism, drug-induced organ toxicity, therapeutic strategies, and future perspectives

Drug-induced toxicity is an important issue in clinical medicine, which typically results in organ dysfunction and adverse health consequences. The family of NOD-like receptors (NLRs) includes intracellular proteins involved in recognizing pathogens and triggering innate immune responses, including the activation of the NLRP3 inflammasome. The NLRP3 (nucleotide-binding oligomerization domain-like receptor family, pyrin domain-containing 3) inflammasome is a critical component for both innate and adaptive immune responses and has been implicated in various drug-induced toxicities, including hepatic, renal, and cardiovascular diseases. The unusual activation of the NLRP3 inflammasome causes the release of pro-inflammatory cytokines, such as IL-1β and IL-18, which can lead to more damage to tissues. Targeting NLRP3 inflammasome is a potential therapeutic endeavour for suppressing drug-induced toxicity. This review provides insights into the mechanism, drug-induced organ toxicity, therapeutic strategies, and prospective therapeutic approaches of the NLRP3 inflammasome and summarizes the developing therapies that target the inflammasome unit. This review has taken up one of the foremost endeavours in understanding and inhibiting the NLRP3 inflammasome as a means of generating safer pharmacological therapies.

Estrogen receptor β activation alleviates inflammatory bowel disease by suppressing NLRP3-dependent IL-1β production in macrophages via downregulation of intracellular calcium level

INTRODUCTION

Although several estrogen receptor β (ERβ) agonists have been reported to alleviate IBD, the pivotal mechanism remains obscure.

OBJECTIVES

To examine the effects and mechanisms of ERβ activation on cytokine/chemokine networks in colitis mice.

METHODS

Dextran sulfate sodium salt (DSS) and trinitro-benzene-sulfonic acid (TNBS) were used to induce mouse colitis model. Multiple molecular biological methods were employed to evaluate the severity of mouse colitis and the level of cytokine and/or chemokine.

RESULTS

Bioinformatics analysis, ELISA and immunofluorescence results showed that the targeted cytokines and/or chemokines associated with ERβ expression and activation is IL-1β, and the anti-colitis effect of ERβ activation was significantly attenuated by the overexpression of AAV9-IL-1β. Immunofluorescence analysis indicated that ERβ activation led to most evident downregulation of IL-1β expression in colonic macrophages as compared to monocytes and neutrophils. Given the pivotal roles of NLRP3, NLRC4, and AIM2 inflammasome activation in the production of IL-1β, we examined the influence of ERβ activation on inflammasome activity. ELISA and WB results showed that ERβ activation selectively blocked the NLRP3 inflammasome assembly-mediated IL-1β secretion. The calcium-sensing receptor (CaSR) and calcium signaling play crucial roles in the assembly of the NLRP3 inflammasome. WB and immunofluorescence results showed that ERβ activation reduced intracellular CaSR expression and calcium signaling in colonic macrophages. Combination with CaSR overexpression plasmid reversed the suppressive effect of ERβ activation on NLRP3 inflammasome assembly, and counteracting the downregulation of IL-1β secretion.

CONCLUSION

Our research uncovers that the anti-colitis effect of ERβ activation is accomplished through the reduction of IL-1β levels in colonic tissue, achieved by specifically decreasing CaSR expression in macrophages to lower intracellular calcium levels and inhibit NLRP3 inflammasome assembly-mediated IL-1β production.

NLRP3 Inflammasome in Vascular Dementia: Regulatory Mechanisms, Functions, and Therapeutic Implications: A Comprehensive Review

BACKGROUND

Vascular dementia, the second most common type of dementia globally after Alzheimer's disease, is associated with neuroinflammation. Activation of the NLRP3 inflammasome, an important pattern recognition receptor in human innate immunity, plays a key role in the pathogenesis of vascular dementia.

RESULTS

The NLRP3 inflammasome pathway destroys neuronal cells primarily through the production of IL-18 and IL-1β. Moreover, it exacerbates vascular dementia by producing IL-18, IL-1β, and the N-terminal fragment of GSDMD, which also contributes to neuronal cell death. Thus, blocking the NLRP3 inflammasome pathway presents a new therapeutic strategy for treating vascular dementia, thereby delaying or curing the disease more effectively and mitigating adverse effects.

CONCLUSIONS

This review explores the role and mechanisms of the NLRP3 inflammasome in vascular dementia, summarizing current research and therapeutic strategies. Investigating the activation of the NLRP3 inflammasome can reveal the pathogenesis of vascular dementia from a new perspective and propose innovative preventive and treatment strategies.

Regulation and therapeutic potential of NLRP3 inflammasome in intestinal diseases

The NOD-like receptor family, particularly the protein 3 that contains the pyrin domain (NLRP3), is an intracellular sensing protein complex responsible for detecting patterns associated with pathogens and injuries. NLRP3 plays a crucial role in the innate immune response. Currently, a wide range of research has indicated the crucial importance of NLRP3 in various inflammatory conditions. Similarly, the NLRP3 inflammasome plays a significant role in preserving intestinal balance and impacting the advancement of diseases. In addition, several randomized trials have demonstrated the safety and efficacy of targeting NLRP3 in the treatment of colitis, colorectal cancer, and related diseases. This review explores the mechanisms of NLRP3 assembly and activation in the gut. We describe its pathological significance in intestinal diseases. Finally, we summarize current and future therapeutic approaches targeting NLRP3 for intestinal diseases.

Thermal Proteome Profiling Reveals Meltome Upon NLRP3 Inflammasome Activation

NOD-like receptor (NLR) family pyrin domain containing 3 (NLRP3) involves in inflammasome complex assembly and innate immunity. Activation of the NLRP3 inflammasome induces conformational alterations in protein complexes, influencing their interactions with other molecules, which in turn affects protein thermal stability. To investigate the proteome-wide thermal stability alterations induced by NLRP3 inflammasome activation, we conducted a comprehensive analysis of meltome dynamics using thermal proteome profiling. Our analysis identified 337 proteins exhibiting alterations in thermal stability upon NLRP3 inflammasome activation. Subsequently, we validated three proteins by the cellular thermal shift assay. Notably, our findings reveal that the majority of these proteins tend to cluster into distinct macromolecular complexes. Furthermore, we identified FAM120A as a novel NLRP3 binding partner, with its suppression enhancing caspase-1 activation and IL-1β release in response to NLRP3 agonist. Collectively, these data provide a comprehensive framework for understanding the mechanisms of NLRP3 inflammasome activation and underscore the utility of thermal proteome profiling in exploring proteome-wide thermal stability changes during signaling transduction.

Activation of the hippocampal CA1 astrocyte Gq and Gi G protein-coupled receptors exerts a protective effect against attention deficit hyperactivity disorder

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is characterized by symptoms such as inattention, hyperactivity and impulsiveness, which significantly impact the healthy development of children. Our prior research demonstrated that exposure to S-Ketamine during pregnancy can lead to the development of ADHD, and existing studies have established a close association between astrocytes and the onset and progression of ADHD. The activation and inhibition of astrocytes are closely linked to neuropsychiatric dysfunction, and astrocytic NOD-like receptor protein 3 (NLRP3) has been reported to contribute to alterations in mental state and cognitive deficits. Thus, this study aims to investigate the role of astrocytes in ADHD by selectively modulating astrocyte function through Gq and Gi G protein-coupled receptors (GPCRs) and by specifically targeting the knockout of NLRP3.

METHODS

Pregnant C57BL/6 J mice or mice with a specific deletion of NLRP3 in astrocytes were administered intraperitoneal injections of 15 mg/kg of S-ketamine for 5 consecutive days from gestational day 14 to 18 to establish an ADHD model. To modulate astrocyte activity in the hippocampal CA1 region, we administered astrocyte-specific Gq-Adeno-associated virus (AAV) or Gi-AAV into the CA1 and maintained treatment with CNO. At 21 days postnatally, we conducted open field test (OFT), novel object recognition (NOR), elevated plus maze (EPM) and fear conditioning (FC) in the offspring mice. Additionally, on postnatal day 21, we implanted electrodes in the CA1 region of the offspring mice for neurophysiological monitoring and investigated local field potentials (LFP) during NOR on postnatal day 27. Lastly, pathological assessments were conducted after euthanasia.

RESULTS

Both the activation and inhibition of astrocytes in the hippocampal CA1 region improved impulsive-like behaviors and cognitive function in ADHD mice, reduced the power of theta (θ) oscillations during novel object exploration and decreased NLRP3-associated inflammatory factors, including cleaved caspase-1 and IL-18. Furthermore, compared to WT mice, astrocyte-specific NLRP3 conditional knockout mice demonstrated significantly reduced impulsive behavior and cognitive deficits, as well as a decrease in θ oscillation power and a reduction in NLRP3-associated inflammatory factors.

CONCLUSIONS

Our data provide compelling evidence that the activation of astrocytes alleviated impulsive-like behaviors and cognitive dysfunction, possibly by reducing NLRP3-associated pyroptosis following changes in calcium levels within the astrocytes. The activation of astrocytes can be a potential therapeutic target for ADHD.

TLR4-mediated endoplasmic reticulum stress regulates pyroptosis in macrophages infected with the Bacillus Calmette-Guérin mycobacterial

Tuberculosis results from Mycobacterium tuberculosis (Mtb) infection. Immune responses controlled by Toll-like receptor 4 (TLR4) are closely associated with the host response to pathogens, including Mtb. NLRP3 inflammasome-mediated pyroptosis forms a significant part of the inflammatory response during Mtb infection, and endoplasmic reticulum stress (ERS) is implicated in the activation of the NLRP3 inflammasome. Here, the function of TLR4 in macrophage pyroptosis induced by infection with the Bacillus Calmette-Guérin (BCG) mycobacterial strain was investigated. It was found that infection with BCG activated TLR4 signaling, induced ERS and subsequent NLRP3 inflammasome activation, leading to pyroptosis in mouse lung tissues. The TLR4 inhibitor TAK 242 inhibited the ERS onset, NLRP3 inflammasome stimulation, and pyroptosis, while the ERS inhibitor TUDCA blocked both inflammasome activation and pyroptosis, and the NLRP3 inhibitor MCC950 specifically inhibited pyroptosis. Furthermore, TAK 242, TUDCA, and MCC950 all exacerbated lung injury caused by BCG infection and promoted BCG survival. Similarly, after in BCG-infected THP-1 macrophages, TLR4 signaling was found to mediate NLRP3 inflammasome activation through ERS, thereby inducing pyroptosis. In summary, BCG infection leads to macrophage pyroptosis via the TLR4/ERS/NLRP3 inflammasome signaling axis, providing new insights for further research into the pathogenesis and treatment of tuberculosis.

EZH2-mediated suppression of TIMP1 in spinal GABAergic interneurons drives microglial activation via MMP-9-TLR2/4-NLRP3 signaling in neuropathic pain

Effective management of neuropathic pain remains a significant challenge due to the limited understanding of its underlying mechanisms. We found that the FDA-approved enhancer of zeste homolog 2 (EZH2) inhibitor, EPZ6438, can prevent the development of neuropathic pain caused by chronic constriction injury (CCI). Therefore, we utilized EPZ6438 as a probe to investigate the molecular events involved in the early stage of neuropathic pain. RNA-seq analysis reveals that EPZ6438 significantly upregulates Timp1 transcription in the spinal cord of mice. As a specific endogenous inhibitor of MMP-9, tissue inhibitor of metalloproteinase 1 (TIMP1) levels significantly decrease in the cerebrospinal fluid of both neuropathic pain patients and the CCI rat models. Importantly, intrathecal administration of mouse recombinant TIMP1 protein (rmTIMP1) reverses CCI-induced mechanical and thermal hyperalgesia. Mechanistically, substance P released from primary sensory neurons suppresses TIMP1 in spinal GABAergic interneurons by elevating EZH2 expression, which enhances H3K27me3 enrichment at the Timp1 promoter. Blocking spinal NK1R effectively prevents the downregulation of TIMP1 and alleviates CCI-induced hyperalgesia. The imbalance between TIMP1 and MMP-9 leads to NLRP3 activation in spinal microglia and increases IL-1β maturation via TLR2/4 pathway. TIMP1 injection eliminates MMP-9-induced NLRP3 activation and blocks hyperalgesia, suggesting that TIMP1 is a critical gatekeeper in preventing neuroinflammation during neuropathic pain development.

The Protective Effects of Vanillic Acid on LPS-induced Acute Lung Injury by Inhibiting STIM1-mediated NLRP3 Inflammasome Activation

Acute lung injury (ALI), which can progress to acute respiratory distress syndrome (ARDS), has inflammation as a crucial factor, especially the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome involvement. Stromal interaction molecule 1 (STIM1) can block NLRP3 activation, but the mechanism is unclear. Vanillic acid, possessing anti-inflammatory properties, has a role in acute lung injury (ALI) whose specific mechanism remains unclear. This study aimed to investigate the effectiveness of vanillic acid in ALI induced by lipopolysaccharides (LPS) and to elucidate the potential mechanisms. In vitro and in vivo experiments were conducted using cells and a mouse model to find out the impact and underlying mechanisms. We found that vanillic acid demonstrated significant inhibition of IL-1β and IL-18 release triggered by LPS and nigericin in J774A.1 cells. The in vivo findings indicated that vanillic acid not only mitigated acute lung injury but also suppressed NLRP3 inflammasome activation in mice. Mechanistically, vanillic acid inhibited the LPS-induced increase in STIM1 expression through the lysosomal degradation pathway. The reduced STIM1 expression diminished intracellular Ca2+ levels, thereby suppressing inflammasome activation and impeding the cleavage and maturation of Caspase-1 and GSDMD, and eventually attenuating cell pyroptosis. Vanillic acid exerts its inhibitory effects on NLRP3 inflammasome activation by promoting STIM1 degradation, thereby ameliorates ALI through impeding NLRP3-GSDMD mediated pyroptosis. The STIM1-NLRP3 signaling axis represents a promising avenue for potential therapeutic interventions in ALI.

Targeting NLRP3 and AIM2 signaling pathways by Viscosol alleviates metabolic dysregulations induced inflammatory responses in diabetic neuro- and nephropathy: An in silico and in vivo study

Type 2 Diabetes (T2D) is a chronic metabolic disorder, considered the fastest growing pandemic of the 21stcentury. Meta-inflammation is a pivotal characteristic of T2D. Hyperactivated PTP1B, NLRP3, and AIM2 inflammasomes are considered the major regulators of metabolic inflammation. The concept of diabetes as an inflammatory disease has changed the pathogenic vision of T2D and hence, the compounds that mitigateinflammation in the setting of T2D are under the limelight of research. Current study aimed to evaluatethe anti-inflammatory potency of Viscosol, a novel PTP1B inhibitor, isolated from Dodonaea viscosa, in the STZ-HFD-induced T2D mouse model. Herein, male mice(C57BL/6), were administrated with Streptozotocin (STZ) (40mg/kg) and Viscosol (33mg/kg), intraperitoneally. Computational profiling revealed good absorption, distribution, metabolism and excretion (ADME) properties, least toxicity, and high docking score of Viscosol with PTP1B(-6.4 kcal/mol), NLRP3(-7.2 kcal/mol), and AIM2(-7.4 kcal/mol). Viscosol treatment significantly restored normal body weight (p < 0.0001), decreased the blood glucose level (p < 0.001), serum ROS level(p < 0.05) and diminished the severity of histopathological lesions, inflammatory lobules and increased the cell count of both brain and kidney tissues. The RT-qPCR analysis showed that Viscosol significantly reduced the mRNA expression of PTP1B, NF-κB, NLRP3, and AIM2up to 2.7-folds, 2.6-folds, 5.7-folds and 14.2-folds in the kidney tissues and 1.6-folds, 1.2-folds, 10.2-folds and 1.5-folds in brain tissues. Conclusively, inhibition of PTP1B via Viscosol could attenuate meta-inflammation by suppressing the aberrant NLRP3 and AIM2 inflammasome signaling in diabetes-linked pathophysiology.

Combination therapies and other therapeutic approaches targeting the NLRP3 inflammasome and neuroinflammatory pathways: a promising approach for traumatic brain injury

OBJECTIVES

Traumatic brain injury (TBI) precipitates a neuroinflammatory cascade, with the NLRP3 inflammasome emerging as a critical mediator. This review scrutinizes the complex activation pathways of the NLRP3 inflammasome by underscoring the intricate interplay between calcium signaling, mitochondrial disturbances, redox imbalances, lysosomal integrity, and autophagy. It is hypothesized that a combination therapy approach-integrating NF-κB pathway inhibitors with NLRP3 inflammasome antagonists-holds the potential to synergistically dampen the inflammatory storm associated with TBI.

METHODS

A comprehensive analysis of literature detailing NLRP3 inflammasome activation pathways and therapeutic interventions was conducted. Empirical evidence supporting the concurrent administration of MCC950 and Rapamycin was reviewed to assess the efficacy of dual-action strategies compared to single-agent treatments.

RESULTS

Findings highlight potassium efflux and calcium signaling as novel targets for intervention, with cathepsin B inhibitors showing promise in mitigating neuroinflammation. Dual therapies, particularly MCC950 and Rapamycin, demonstrate enhanced efficacy in reducing neuroinflammation. Autophagy promotion, alongside NLRP3 inhibition, emerges as a complementary therapeutic avenue to reverse neuroinflammatory damage.

CONCLUSION

Combination therapies targeting the NLRP3 inflammasome and related pathways offer significant potential to enhance recovery in TBI patients. This review presents compelling evidence for the development of such strategies, marking a new frontier in neuroinflammatory research and therapeutic innovation.

NLRP3 inflammasome: significance and potential therapeutic targets to advance solid organ transplantation

INTRODUCTION

NOD-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome, integral to innate immunity, has become a pivotal figure in the inflammatory cascade.

AREAS COVERED

This article provides an overview of the NLRP3 inflammasome, reviewing its complicated structure, as well as the diverse signals that trigger its assembly. Furthermore, we explored the intricate relationship between the NLRP3 inflammasome and acute and chronic rejection in solid organ transplantation. Solid organ transplantation stands as a crucial medical intervention, yet its efficacy is challenged by immune-mediated complications, including acute rejection, ischemia-reperfusion injury, and chronic allograft rejection. We also investigated the encouraging potential of immunosuppressive therapies targeting NLRP3 signaling to alleviate inflammatory responses linked to transplantation.

EXPERT OPINION

In recent years, the NLRP3 inflammasome has garnered considerable attention owing to its critical functions spanning diverse fields. This study highlights the critical function of the NLRP3 inflammasome and presents insights, offering fresh perspectives on how its modulation might help to improve the outcomes among patients who undergo solid organ transplantations.

Inflammasomes and Cardiovascular Disease: Linking Inflammation to Cardiovascular Pathophysiology

Cardiovascular diseases (CVDs) remain a leading cause of global mortality, driven by risk factors such as dyslipidemia, hypertension and diabetes. Recent research has highlighted the critical role of inflammasomes, particularly the NLRP3 inflammasome, in the pathogenesis of various CVDs, including hypertension, atherosclerosis, myocardial infarction and heart failure. Inflammasomes are intracellular protein complexes that activate inflammatory responses through the production of pro-inflammatory cytokines such as IL-1β and IL-18, contributing to endothelial dysfunction, plaque formation and myocardial injury. This review provides a comprehensive overview of the structure, activation mechanisms and pathways of inflammasomes, with a focus on their involvement in cardiovascular pathology. Key activation pathways include ion fluxes (K+ efflux and Ca2+ signalling), endoplasmic reticulum (ER) stress, mitochondrial dysfunction and lysosomal destabilisation. The review also explores the therapeutic potential of targeting inflammasomes to mitigate inflammation and improve outcomes in CVDs. Emerging strategies include small-molecule inhibitors, biologics and RNA-based therapeutics, with a particular emphasis on NLRP3 inhibition. Additionally, the integration of artificial intelligence (AI) in cardiovascular research offers promising avenues for identifying novel biomarkers, predicting disease risk and developing personalised treatment strategies. Future research directions should focus on understanding the interactions between inflammasomes and other immune components, as well as genetic regulators, to uncover new therapeutic targets. By elucidating the complex role of inflammasomes in CVDs, this review underscores the potential for innovative therapies to address inflammation-driven cardiovascular pathology, ultimately improving patient outcomes.

Targeting the NLRP3 inflammasome in Parkinson's disease: From molecular mechanism to therapeutic strategy

Parkinson's disease is the second most common neurodegenerative disease, characterized by substantial loss of dopaminergic (DA) neurons, the formation of Lewy bodies (LBs) in the substantia nigra, and pronounced neuroinflammation. The nucleotide-binding domain like leucine-rich repeat- and pyrin domain-containing protein 3 (NLRP3) inflammasome is one of the pattern recognition receptors (PRRs) that function as intracellular sensors in response to both pathogenic microbes and sterile triggers associated with Parkinson's disease. These triggers include reactive oxygen species (ROS), misfolding protein aggregation, and potassium ion (K+) efflux. Upon activation, it recruits and activates caspase-1, then processes the pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18, which mediate neuroinflammation in Parkinson's disease. In this review, we provide a comprehensive overview of NLRP3 inflammasome, detailing its structure, activation pathways, and the factors that trigger its activation. We also explore the pathological mechanisms by which NLRP3 contributes to Parkinson's disease and discuss potential strategies for targeting NLRP3 as a therapeutic approach.

PLC and PAD2 Regulate Extracellular Calcium-Triggered Release of Macrophage Extracellular DNA Traps

Macrophages can respond to infection or cellular stress by forming inflammasomes or by releasing extracellular traps (ETs) of DNA through METosis. While ETs have been extensively studied in neutrophils, there are fewer studies on METosis. We show that extracellular calcium and LPS enable human monocyte-derived macrophages (hMDM) to release extracellular DNA decorated with myeloperoxidase (MPO) and citrullinated histone, alongside ASC aggregation and IL-1ß maturation, indicating NLRP3 inflammasome activation. Compared with m-CSF differentiated macrophages only gm-CSF differentiated macrophages expressed macrophage elastase (MMP12) and METs released by the latter had significantly more bactericidal activity toward E. coli. Mechanistically, phospholipase C and peptidyl arginine deiminase-2 inhibition attenuate MET release. Interestingly, NLRP3 inflammasome blockade by MCC950 had a significant effect on MET release. Finally, MET release was completely blocked by plasma membrane stabilization by punicalagin. Altogether, we demonstrate that extracellular calcium-activated hMDM extrude DNA, containing citrullinated histones, MPO, MMP12, and ASC specks and released METs kill bacteria independent of hMDM phagocytotic activity. We believe that calcium-activated hMDM adds a physiologically relevant condition to calcium ionophore induced cell death that may be important in autoimmunity.

NLRP3 inflammasome-based therapies by natural products: a new development in the context of cancer therapy

The leucine-rich repeat containing protein (NLR) canonical inflammasome family includes Nod-like receptor protein 3 (NLRP3). Via the mediation of apoptosis proteins and immunological reactions, it controls the pathogenesis of malignancy. Experimental studies showed a relationship among lymphogenesis, cancer metastasis, and NLRP3 expression. Natural products have also been used as lead-based substances in a number of investigations to speed up the creation of novel, specific NLRP3 inhibitors. Via the mediation of apoptotic proteins and immunological responses, it controls the pathogenesis of malignancy. Moreover, it was recently noted that among human cancers, chemotherapy activates NLRP3. Induction of NLRP3 could encourage the generation of IL-1β and IL-22 to facilitate the propagation of malignancy. Additionally, prior research has demonstrated that the usage of NLRP3 in cancer therapy may result in resistance to drugs. The depletion of NLRP3 could affect the survival of cells. Natural products have been used as lead materials in a number of studies to help generate novel, specific NLRP3 antagonists more quickly. In the present review, we examine the mechanism behind the beneficial effects of the natural substances on the inhibition of cancer growth and progression, with special focus on NLRP3 regulation.

Purinergic receptor P2X7 regulates interleukin-1α mediated inflammation in chronic kidney disease in a reactive oxygen species-dependent manner

Onset, progression and cardiovascular outcome of chronic kidney disease (CKD) are influenced by the concomitant sterile inflammation. The pro-inflammatory cytokine family interleukin (IL)-1 is crucial in CKD with the key alarmin IL-1α playing an additional role as an adhesion molecule that facilitates immune cell tissue infiltration and consequently inflammation. Here, we investigate calcium ion and reactive oxygen species (ROS)-dependent regulation of different aspects of IL-1α-mediated inflammation. We show that human CKD monocytes exhibit altered purinergic calcium ion signatures. Monocyte IL-1α release was reduced when inhibiting P2X7, and to a lesser extent P2X4, two ATP-receptors that were found upregulated compared to monocytes from healthy people. In murine CKD models, deleting P2X7 (P2X7-/-) abolished IL-1α release but increased IL-1α surface presentation by bone marrow derived macrophages and impaired immune cell infiltration of the kidney without protecting kidney function. In contrast, immune cell infiltration into injured wild type and P2X7-/- hearts was comparable in a myocardial infarction model, independent of previous kidney injury. Both the chimeric mouse line harboring P2X7-/- immune cells in wild type recipient mice, and the inversely designed chimeric line showed less acute inflammation. However, only the chimera harboring P2X7-/- immune cells showed a striking resistance against injury-induced cardiac remodeling. Mechanistically, ROS measurements reveal P2X7-induced mitochondrial ROS as an essential factor for IL-1α release by monocytes. Our studies uncover a dual role of P2X7 in regulating IL-1α biogenesis with consequences for inflammation and inflammation-induced deleterious cardiac remodeling that may determine clinical outcomes in CKD therapies.

Thermosensitive TRPM2: The regulatory mechanisms of its temperature sensitivity and physiological functions

Transient receptor potential melastatin 2 (TRPM2) is a non-selective cation channel with high Ca2+ permeability. TRPM2 exhibits temperature sensitivity, detecting warm to noxious high temperatures. This temperature sensitivity is regulated by several endogenous factors, including reactive oxygen species, adenosine diphosphate ribose, Ca2+ ions, and TRPM2 phosphorylation by protein kinase C, which alter TRPM2 activity at body temperature. Consequently, at core body temperature, TRPM2 regulates the physiological functions of TRPM2-expressing cells and tissues, such as immunocytes, pancreatic β cells, and the brain. In contrast, TRPM2 in sensory neurons detects warm temperatures. The current review summarizes the regulatory mechanisms of TRPM2 and its roles in physiological processes, focusing on temperature-dependent phenomena.

Natural and synthetic potential drug leads for rheumatoid arthritis probing innovative target: mitochondrial dysfunction and NLRP3 inflammasome activation

Rheumatoid arthritis (RA) is an autoimmune, chronic, inflammatory disease characterized by synovial hyperplasia, bone erosion, progressive joint deterioration, and excruciating joint pain. Worldwide RA prevalence is approximately 0.1-2%, affecting women and elderly population. Limited knowledge of disease pathogenesis causes hindrance in diagnosis and treatment of RA. Deep investigation of RA pathogenesis is deemed, for the development of novel therapies. Among diverse targets for RA, proper functioning of mitochondria is essential for endurance of synovial cells and chondrocytes. Once mitochondria are damaged, these affect immune and non-immune cells in terms of their activation, survival, and differentiation prima to occurrence of RA. An innate immune complex, NLRP3 (NOD-like receptor family pyrin domain-containing 3) inflammasome plays pivotal role in RA pathogenesis through its control on the synthesis of pro-inflammatory cytokines (IL-1β & IL-18) and induction of pyroptotic cell death. Mitochondrial dysfunction is the possible primary cause of NLRP3 inflammasome activation, leading to inflammation and joint destruction in RA. This review emphasizes that how mitochondrial dysregulation affect NLRP3 inflammasome activation and contribute to RA's inflammatory cascade. It also investigates synthetic and natural substances including Berberine, Ebselen, and Resveratrol that have emerged as promising drug leads for RA by modulating mitochondrial dysfunction and inhibiting NLRP3 inflammasome activation. Furthermore, it concise the evidences from RA-associated animal models explaining beneficial impact of various therapeutic agents in attenuation of inflammation and deterioration of bone and cartilage. Hence, the current review stresses molecular pathways in mitochondrial dynamics and NLRP3 inflammasome activation, as an approach to hone RA treatment goals.

NLRP3 inflammasome in cardiovascular diseases: an update

Cardiovascular disease (CVD) continues to be the leading cause of mortality worldwide. The nucleotide oligomerization domain-, leucine-rich repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is involved in numerous types of CVD. As part of innate immunity, the NLRP3 inflammasome plays a vital role, requiring priming and activation signals to trigger inflammation. The NLRP3 inflammasome leads both to the release of IL-1 family cytokines and to a distinct form of programmed cell death called pyroptosis. Inflammation related to CVD has been extensively investigated in relation to the NLRP3 inflammasome. In this review, we describe the pathways triggering NLRP3 priming and activation and discuss its pathogenic effects on CVD. This study also provides an overview of potential therapeutic approaches targeting the NLRP3 inflammasome.

Evolution of Biological Hydroxyapatite Modification Strategy: Anti-Inflammation Approach Rescues the Calcium-NOD-Like Receptor-Inflammation Axis-Mediated Periodontal Redevelopment Failure

Periodontal regenerative medicine is currently undergoing a paradigm shift from dissecting the healing process toward utilization of the developmental program. Biological hydroxyapatite (BHA), a major component of guided tissue regeneration, has long been optimized for inducing multidirectional differentiation of periodontal ligament cells (PDLCs). However, this approach runs counter to the redevelopment strategy. Thus, the conventional BHA should evolve to induce the redevelopment process of periodontal tissue. In this study, histopathological changes and immune microenvironment characteristics of the periodontal developmental process, natural healing process (Blank group), and BHA-mediated healing process (BHA group) were compared to evaluate the main manifestations of BHA-mediated periodontal "developmental engineering" outcome. Our results suggested that neither the Blank nor BHA group could recur key events in periodontal development. The implantation of BHA led to pro-inflammatory immune microenvironment and an unstable blood fibrin clot structure, which facilitated the invasion of outer gingival fibroblasts, consequently disrupting redevelopmental events. High-throughput chip technology was further used to explore the underlying mechanism of immune activation, revealing that the calcium-NOD-like receptor-inflammation axis signaling axis promoted the activation of pro-inflammatory immune response that contributed to redevelopment failure. An immunomodulatory cytokine interleukin 4 (IL4)-modified BHA was used to further validate the efficacy of developmental engineering strategy. IL4 could partially rescued the redevelopment failure through immunosuppression. This study presented an innovative strategy for the development of advanced periodontal regenerative materials and offered a potential approach for the application of development-inspired periodontal tissue engineering strategies. It represented a marked advancement in the development of regenerative medicine and propelled the clinical organ restoration forward.

Ginsenoside Rb1 ameliorates apical periodontitis via suppressing macrophage pyroptosis

OBJECTIVES

The objectives of current study were to investigate the role and related mechanism of Ginsenoside Rb1 (GRb1) on regulating apical periodontitis (AP) prognosis.

MATERIALS AND METHODS

Clinical specimens were used to determine the involvement of calcium overload-induced macrophage pyroptosis in periapical tissues. Next, a calcium ion-chelating agent (BAPTA-AM) was applied to detect the suppression of intracellular calcium overload in macrophage pyroptosis. Then, network pharmacology, western blot (WB) analysis, and Fluo-4 calcium assay were conducted to explore the role of GRb1 on intracellular calcium overload. To gain a better understanding of GRb1 in calcium overload-induced macrophage pyroptosis linked AP, GRb1-treated AP models were established.

RESULTS

We discovered clinically and experimentally that calcium overload-dependent macrophage pyroptosis is involved in AP pathogenesis, and reducing calcium overload greatly decreased macrophage pyroptosis in an AP cell model. Next, based on GRb1's inhibitory role in aberrant intracellular calcium accumulation, we discovered that GRb1 alleviates AP by suppressing calcium-dependent macrophage pyroptosis in both in vitro and in vivo models.

CONCLUSIONS

GRb1 is an effective therapeutic strategy to rescue the periapical tissues from inflammation due to its anti-pyroptosis function. Thus, the present study supports further investigation of GRb1 as an adjuvant therapy for AP.

Purinergic signaling in liver disease: calcium signaling and induction of inflammation

Purinergic signaling regulates many metabolic functions and is implicated in liver physiology and pathophysiology. Liver functionality is modulated by ionotropic P2X and metabotropic P2Y receptors, specifically P2Y1, P2Y2, and P2Y6 subtypes, which physiologically exert their influence through calcium signaling, a key second messenger controlling glucose and fat metabolism in hepatocytes. Purinergic receptors, acting through calcium signaling, play an important role in a range of liver diseases. Ionotropic P2X receptors, such as the P2X7 subtype, and certain metabotropic P2Y receptors can induce aberrant intracellular calcium transients that impact normal hepatocyte function and initiate the activation of other liver cell types, including Kupffer and stellate cells. These P2Y- and P2X-dependent intracellular calcium increases are particularly relevant in hepatic disease states, where stellate and Kupffer cells respond with innate immune reactions to challenges, such as excess fat accumulation, chronic alcohol abuse, or infections, and can eventually lead to liver fibrosis. This review explores the consequences of excessive extracellular ATP accumulation, triggering calcium influx through P2X4 and P2X7 receptors, inflammasome activation, and programmed cell death. In addition, P2Y2 receptors contribute to hepatic steatosis and insulin resistance, while inhibiting the expression of P2Y6 receptors can alleviate alcoholic liver steatosis. Adenosine receptors may also contribute to fibrosis through extracellular matrix production by fibroblasts. Thus, pharmacological modulation of P1 and P2 receptors and downstream calcium signaling may open novel therapeutic avenues.

Exploring the mechanism and crosstalk between IL-6 and IL- 1β on M2 macrophages under metabolic stress conditions

Macrophages are highly variable immune cells that are important in controlling inflammation and maintaining tissue balance. The ability to polarize into two major types-M1, promoting inflammation, and M2, resolving inflammation and contributing to tissue repair-determines their specific roles in health and disease. M2 macrophages are particularly important for reducing inflammation and promoting tissue regeneration, but their function is shaped mainly by surrounding cells. This is evident in obesity, diabetes, and chronic inflammation. Although many cytokines regulate macrophage polarization, interleukin-6 (IL-6) and interleukin-1β (IL-1β) are major players, but their effects on M2 macrophage behavior under metabolic stress remain unclear. This study describes the intricacies within M2 macrophages concerning IL-6 and IL-1β signaling when under metabolic stress. Though, more frequently than not, IL-6 is labelled as pro-inflammatory, it can also behave as an anti-inflammatory mediator. On the other hand, IL-1β is the main pro-inflammatory agent, particularly in metabolic disorders. The relationship between these cytokines and the macrophages is mediated through important pathways such as JAK/STAT and NFκB, which get perturbed by metabolic stress. Therefore, metabolic stress also alters the functional parameters of macrophages, including alterations in mitochondrial metabolism, glycolytic and oxidative metabolism. Phosphorylation alters the kinetics involved in energy consumption and affects their polarization and their function. However, it has been suggested that IL-6 and IL-1β may work in concert or competition when inducing M2 polarization and, importantly, implicate cytokine release, phagocytic activity, and tissue repair processes. In this review, we discuss the recent literature on the participation of IL-6 and IL-1β cytokines in macrophage polarization and how metabolic stress changes cytokine functions and synergistic relations. A better understanding of these cytokines would serve as an important step toward exploring alternative antiviral strategies directed against metabolic disturbance and, hence, approve further endeavors.

MAM-STAT3-Driven Mitochondrial Ca+2 Upregulation Contributes to Immunosenescence in Type A Mandibuloacral Dysplasia Patients

Individuals with homozygous laminA/C p.R527C mutations manifest a severe form of Mandibuloacral dysplasia-(MAD) and exhibit overlapping progeroid symptoms, for which the underlying molecular pathology remains unknown. Herein, it is shown that MAD patients achieved inflammaging with different pro-inflammatory cytokines compared to progeria-(HGPS) patient. Characterization of MAD iPSC-derived Mesenchymal stem cells (MAD-iMSC) uncovers deregulated mitochondrial Ca+2 as the primary cause of inflammaging, mediated through inflammasome formation rather than the cGAS-STING pathway. Moreover, MAD-iMSCs extracellular vesicles (EVs) can also upregulate mitochondrial Ca+2 in healthy cells. This deregulated Ca+2 homeostasis is indirectly mediated by mitochondrial calcium mediator, signal transducer, and activator of transcription-3 (STAT3), situated on the mitochondrial associated membrane (MAM). Inflammaging is mitigated by various FDA-approved MAM-STAT3 upstream inhibitors, such as (Tocilizumab) or by correcting R527C mutation with CRISPR/CAS9. These results provide new insights into MAD disease and propose targeting defective mitochondrial Ca+2 homeostasis as a promising therapy for reversing immunosenescence.

Targeting the NLRP3 inflammasome as a novel therapeutic target for osteoarthritis

Osteoarthritis, the most common arthritic condition, is an age-related progressive disease characterized by the loss of cartilage and synovial inflammation in the knees and hips. Development of pain, stiffness, and considerably restricted mobility of the joints are responsible for the production of matrix metalloproteinases and cytokines. Although several treatments are available for the management of this disease condition, they possess limitations at different levels. Recently, efforts have focused on regulating the production of the NLRP3 inflammasome, which plays a critical role in the disease's progression due to its dysregulation. Inhibition of NLRP3 inflammasome has shown the potential to modulate the production of MMP-13, caspase-1, IL-1β, etc., which has been reflected by positive responses in different preclinical and clinical studies. Aiming inhibition of this NLRP3 inflammasome, several compounds are in different stages of research owing to bring a novel agent for the treatment of osteoarthritis. This review summarizes the mechanistic pathways linking NLRP3 activation to osteoarthritis development and discusses the progress in new therapeutics aimed at effective treatment.

Active ingredients of traditional Chinese medicine inhibit NOD-like receptor protein 3 inflammasome: a novel strategy for preventing and treating heart failure

Heart failure (HF) has emerged as a significant global public health challenge owing to its high rates of morbidity and mortality. Activation of the NOD-like receptor protein 3 (NLRP3) inflammasome is regarded as a pivotal factor in the onset and progression of HF. Therefore, inhibiting the activation of the NLRP3 inflammasome may represent a promising therapeutic approach for preventing and treating HF. The active ingredients serve as the foundation for the therapeutic effects of traditional Chinese medicine (TCM). Recent research has revealed significant advantages of TCM active ingredients in inhibiting the activation of the NLRP3 inflammasome and enhancing cardiac structure and function in HF. The study aimed to explore the impact of NLRP3 inflammasome activation on the onset and progression of HF, and to review the current advancements in utilizing TCM active ingredients to inhibit the NLRP3 inflammasome for preventing and treating HF. This provides a novel perspective for the future development of precise intervention strategies targeting the NLRP3 inflammasome to prevent and treat HF.

Preventing NLRP3 inflammasome activation: Therapeutic atrategy and challenges in atopic dermatitis

Atopic dermatitis (AD) is a prevalent inflammatory skin disorder characterized by its chronic, persistent, and recurrent nature. The pathophysiology of this condition is complex, involving various factors including cell-mediated immune responses, compromised skin barrier function, and alterations in hypersensitivity reactions. These components synergistically contribute to the perpetuation of the bothersome "itch-scratch-itch" cycle. Recent research has highlighted the significant role of the NLRP3 inflammasome in the development of AD and other inflammatory conditions. Current research indicates that the NLRP3 inflammasome plays a pivotal role in both the acute and chronic phases of AD by modulating the Th2/Th1 immune deviation. Moreover, the pharmacological suppression of NLRP3 has shown promising results in mitigating the pathological aspects of AD. This review outlines potential drug development strategies that target the NLRP3 inflammasome as a therapeutic approach for AD and the challenges faced in this endeavor.

Apigenin inhibits NLRP3 inflammasome activation in monocytes and macrophages independently of CD38

Introduction

CD38, a regulator of intracellular calcium signalling, is highly expressed in immune cells. Mice lacking CD38 are very susceptible to acute bacterial infections, implicating CD38 in innate immune responses. The effects of CD38 inhibition on NLRP3 inflammasome activation in human primary monocytes and monocyte-derived macrophages have not been investigated. Apigenin is a naturally occurring flavonoid known to inhibit CD38. However, apigenin has also been proposed to inhibit the extracellular ATP receptor P2XR7, an upstream activator of NLRP3. In this study we aimed to investigate whether apigenin attenuates NLRP3 inflammasome activation in human monocytes and monocyte-derived macrophages through CD38 inhibition.

Methods

LPS-primed human monocytes and monocyte-derived macrophages were treated with apigenin, the CD38 inhibitor 78c, antagonists of CD38 second messengers (8-br-ADPR and 8-br-cADPR) or the ATP hydrolase, apyrase, prior to NLRP3 activation with ATP, monosodium urate crystals (MSU) or nigericin. IL-1β and TNF secretion and mRNA expression, as well as N-terminal gasdermin-D formation were quantified. Ca2+ mobilization was determined by live confocal microscopy. NLRP3 activity was also compared in WT and CD38-/- mouse bone marrow-derived macrophages (BMDMs) with and without CD38 inhibitors.

Results

Apigenin significantly inhibited IL-1β release from LPS-primed monocytes and macrophages activated with ATP, MSU, or nigericin. CD38 inhibition with 78c also attenuated NLRP3-dependent IL-1β release. Apigenin was a potent inhibitor of Ca2+ flux from the endoplasmic reticulum to the cytosol in human monocyte-derived macrophages. Apyrase attenuated IL-1β release induced by ATP or MSU, but not by nigericin. However, the NLRP3 inflammasome is not compromised in CD38-/- bone marrow-derived macrophages compared to corresponding WT cells, and apigenin moderated IL-1β release in both genotypes.

Discussion

Our data support that apigenin attenuates NLRP3 activation independently of CD38. Our results also suggest that MSU crystals activate NLRP3 through autocrine or paracrine ATP signalling.

Regulation of the NLRP3 inflammasome by autophagy and mitophagy

The NLRP3 inflammasome is a multiprotein complex that upon activation by the innate immune system drives a broad inflammatory response. The primary initial mediators of this response are pro-IL-1β and pro-IL-18, both of which are in an inactive form. Formation and activation of the NLRP3 inflammasome activates caspase-1, which cleaves pro-IL-1β and pro-IL-18 and triggers the formation of gasdermin D pores. Gasdermin D pores allow for the secretion of active IL-1β and IL-18 initiating the organism-wide inflammatory response. The NLRP3 inflammasome response can be beneficial to the host; however, if the NLRP3 inflammasome is inappropriately activated it can lead to significant pathology. While the primary components of the NLRP3 inflammasome are known, the precise details of assembly and activation are less well defined and conflicting. Here, we discuss several of the proposed pathways of activation of the NLRP3 inflammasome. We examine the role of subcellular localization and the reciprocal regulation of the NLRP3 inflammasome by autophagy. We focus on the roles of mitochondria and mitophagy in activating and regulating the NLRP3 inflammasome. Finally, we detail the impact of pathologic NLRP3 responses in the development and manifestations of pulmonary disease.

Ketone body metabolism and the NLRP3 inflammasome in Alzheimer's disease

Alzheimer's disease (AD) is a degenerative brain disorder and the most common form of dementia. AD pathology is characterized by senile plaques and neurofibrillary tangles (NFTs) composed of amyloid-β (Aβ) and hyperphosphorylated tau, respectively. Neuroinflammation has been shown to drive Aβ and tau pathology, with evidence suggesting the nod-like receptor family pyrin domain containing 3 (NLRP3) inflammasome as a key pathway in AD pathogenesis. NLRP3 inflammasome activation in microglia, the primary immune effector cells of the brain, results in caspase-1 activation and secretion of IL-1β and IL-18. Recent studies have demonstrated a dramatic interplay between the metabolic state and effector functions of immune cells. Microglial metabolism in AD is of particular interest, as ketone bodies (acetone, acetoacetate (AcAc), and β-hydroxybutyrate (BHB)) serve as an alternative energy source when glucose utilization is compromised in the brain of patients with AD. Furthermore, reduced cerebral glucose metabolism concomitant with increased BHB levels has been demonstrated to inhibit NLRP3 inflammasome activation. Here, we review the role of the NLRP3 inflammasome and microglial ketone body metabolism in AD pathogenesis. We also highlight NLRP3 inflammasome inhibition by several ketone body therapies as a promising new treatment strategy for AD.

The intricate interactions between inflammasomes and bacterial pathogens: Roles, mechanisms, and therapeutic potentials

Inflammasomes are intracellular multiprotein complexes that consist of a sensor, an adaptor, and a caspase enzyme to cleave interleukin (IL)-1β and IL-18 into their mature forms. In addition, caspase-1 and -11 activation results in the cleavage of gasdermin D to form pores, thereby inducing pyroptosis. Activation of the inflammasome and pyroptosis promotes host defense against pathogens, whereas dysregulation of the inflammasome can result in various pathologies. Inflammasomes exhibit versatile microbial signal detection, directly or indirectly, through cellular processes, such as ion fluctuations, reactive oxygen species generation, and the disruption of intracellular organelle function; however, bacteria have adaptive strategies to manipulate the inflammasome by altering microbe-associated molecular patterns, intercepting innate pathways with secreted effectors, and attenuating inflammatory and cell death responses. In this review, we summarize recent advances in the diverse roles of the inflammasome during bacterial infections and discuss how bacteria exploit inflammasome pathways to establish infections or persistence. In addition, we highlight the therapeutic potential of harnessing bacterial immune subversion strategies against acute and chronic bacterial infections. A more comprehensive understanding of the significance of inflammasomes in immunity and their intricate roles in the battle between bacterial pathogens and hosts will lead to the development of innovative strategies to address emerging threats posed by the expansion of drug-resistant bacterial infections.

MAP Kinase Signaling at the Crossroads of Inflammasome Activation

Inflammasomes are crucial mediators of both antimicrobial host defense and inflammatory pathology, requiring stringent regulation at multiple levels. This review explores the pivotal role of mitogen-activated protein kinase (MAPK) signaling in modulating inflammasome activation through various regulatory mechanisms. We detail recent advances in understanding MAPK-mediated regulation of NLRP3 inflammasome priming, licensing and activation, with emphasis on MAPK-induced activator protein-1 (AP-1) signaling in NLRP3 priming, ERK1 and JNK in NLRP3 licensing, and TAK1 in connecting death receptor signaling to NLRP3 inflammasome activation. Furthermore, we discuss novel insights into MAPK signaling in human NLRP1 inflammasome activation, focusing on the MAP3K member ZAKα as a key kinase linking ribosomal stress to inflammasome activation. Lastly, we review recent work elucidating how Bacillus anthracis lethal toxin (LeTx) manipulates host MAPK signaling to induce macrophage apoptosis as an immune evasion strategy, and the counteraction of this effect through genotype-specific Nlrp1b inflammasome activation in certain rodent strains.

Breaking the barriers: Overcoming cancer resistance by targeting the NLRP3 inflammasome

Inflammation has a pivotal role in the initiation and progression of various cancers, contributing to crucial processes such as metastasis, angiogenesis, cell proliferation and invasion. Moreover, the release of cytokines mediated by inflammation within the tumour microenvironment (TME) has a crucial role in orchestrating these events. The activation of inflammatory caspases, facilitated by the recruitment of caspase-1, is initiated by the activation of pattern recognition receptors on the immune cell membrane. This activation results in the production of proinflammatory cytokines, including IL-1β and IL-18, and participates in diverse biological processes with significant implications. The NOD-Like Receptor Protein 3 (NLRP3) inflammasome holds a central role in innate immunity and regulates inflammation through releasing IL-1β and IL-18. Moreover, it interacts with various cellular compartments. Recently, the mechanisms underlying NLRP3 inflammasome activation have garnered considerable attention. Disruption in NLRP3 inflammasome activation has been associated with a spectrum of inflammatory diseases, encompassing diabetes, enteritis, neurodegenerative diseases, obesity and tumours. The NLRP3 impact on tumorigenesis varies across different cancer types, with contrasting roles observed. For example, colorectal cancer associated with colitis can be suppressed by NLRP3, whereas gastric and skin cancers may be promoted by its activity. This review provides comprehensive insights into the structure, biological characteristics and mechanisms of the NLRP3 inflammasome, with a specific focus on the relationship between NLRP3 and tumour-related immune responses, and TME. Furthermore, the review explores potential strategies for targeting cancers via NLRP3 inflammasome modulation. This encompasses innovative approaches, including NLRP3-based nanoparticles, gene-targeted therapy and immune checkpoint inhibitors.

The Central Role of Interleukin-1 Signalling in the Pathogenesis of Kawasaki Disease Vasculitis: Path to Translation

Kawasaki disease (KD) manifests as an acute febrile condition and systemic vasculitis, the etiology of which remains elusive. Primarily affecting children under 5 years of age, if untreated KD can lead to a significant risk of coronary artery aneurysms and subsequent long-term cardiovascular sequelae, including myocardial ischemia and myocardial infarction. Intravenous immunoglobulin therapy mitigates the risk of aneurysm formation, but a subset of patients exhibit resistance to this treatment, increasing the susceptibility of coronary artery lesions. Furthermore, the absence of a KD-specific diagnostic test or biomarkers complicates early detection and appropriate treatment. Experimental murine models of KD vasculitis have substantially improved our understanding of the disease pathophysiology, revealing the key roles of the NLRP3 inflammasome and interleukin-1 (IL-1) signalling pathway. This review aims to delineate the pathophysiologic findings of KD while summarising the findings for the emerging key role of IL-1β in its pathogenesis, derived from both human data and experimental murine models, and the translational potential of these findings for anti-IL-1 therapies for children with KD.

Gelsolin alleviates rheumatoid arthritis by negatively regulating NLRP3 inflammasome activation

Despite numerous biomarkers being proposed for rheumatoid arthritis (RA), a gap remains in our understanding of their mechanisms of action. In this study, we discovered a novel role for gelsolin (GSN), an actin-binding protein whose levels are notably reduced in the plasma of RA patients. We elucidated that GSN is a key regulator of NLRP3 inflammasome activation in macrophages, providing a plausible explanation for the decreased secretion of GSN in RA patients. We found that GSN interacts with NLRP3 in LPS-primed macrophages, hence modulating the formation of the NLRP3 inflammasome complex. Reducing GSN expression significantly enhanced NLRP3 inflammasome activation. GSN impeded NLRP3 translocation to the mitochondria; it contributed to the maintenance of intracellular calcium equilibrium and mitochondrial stability. This maintenance is crucial for controlling the inflammatory response associated with RA. Furthermore, the exacerbation of arthritic symptoms in GSN-deficient mice indicates the potential of GSN as both a diagnostic biomarker and a therapeutic target. Moreover, not limited to RA models, GSN has demonstrated a protective function in diverse disease models associated with the NLRP3 inflammasome. Myeloid cell-specific GSN-knockout mice exhibited aggravated inflammatory responses in models of MSU-induced peritonitis, folic acid-induced acute tubular necrosis, and LPS-induced sepsis. These findings suggest novel therapeutic approaches that modulate GSN activity, offering promise for more effective management of RA and a broader spectrum of inflammatory conditions.

Neuroinflammation in Age-Related Neurodegenerative Diseases: Role of Mitochondrial Oxidative Stress

A shared hallmark of age-related neurodegenerative diseases is the chronic activation of innate immune cells, which actively contributes to the neurodegenerative process. In Alzheimer's disease, this inflammatory milieu exacerbates both amyloid and tau pathology. A similar abnormal inflammatory response has been reported in Parkinson's disease, with elevated levels of cytokines and other inflammatory intermediates derived from activated glial cells, which promote the progressive loss of nigral dopaminergic neurons. Understanding the causes that support this aberrant inflammatory response has become a topic of growing interest and research in neurodegeneration, with high translational potential. It has been postulated that the phenotypic shift of immune cells towards a proinflammatory state combined with the presence of immunogenic cell death fuels a vicious cycle in which mitochondrial dysfunction plays a central role. Mitochondria and mitochondria-generated reactive oxygen species are downstream effectors of different inflammatory signaling pathways, including inflammasomes. Dysfunctional mitochondria are also recognized as important producers of damage-associated molecular patterns, which can amplify the immune response. Here, we review the major findings highlighting the role of mitochondria as a checkpoint of neuroinflammation and immunogenic cell deaths in neurodegenerative diseases. The knowledge of these processes may help to find new druggable targets to modulate the inflammatory response.

Comparison of the Cecum Ligation and Puncture Method and the Intraperitoneal Lipopolysaccharide Injection Method for the Construction of a New-Onset Atrial Fibrillation Model of Sepsis

Background

New-onset atrial fibrillation (AF) in sepsis significantly impacted patient morbidity and mortality, yet the optimal animal model for studying this condition remains undetermined. This study aimed to establish a stable animal model for new-onset AF in sepsis and to explore the molecular mechanisms involved.

Methods

Forty-seven Sprague-Dawley rats were utilized, with the cecal ligation and puncture (CLP) group divided into 0.6 mm and 1.0 mm needle outer diameter subgroups, and the lipopolysaccharide (LPS) group into 5 mg/kg, 10 mg/kg, 15 mg/kg, and 20 mg/kg dosage subgroups. The incidence of new-onset AF and five-day mortality rates were compared to identify the most stable modeling conditions. Selected subgroups underwent further analysis, including cardiac ultrasound, electrophysiology, and pathological examinations. Inflammation-related molecular levels in the atrium were assessed using ELISA and Western blotting (WB).

Results

The intraperitoneal injection of 10 mg/kg LPS was identified as the most stable model for new-onset AF in sepsis, with significant findings including increased left atrial area and fibrosis, left ventricular pump dysfunction, uncoordinated ventricular wall motion, and impaired electrical impulse conduction. The effective atrial refractory period was markedly shorter, and susceptibility to AF was higher in the LPS group compared to the CLP group. Molecular analysis revealed elevated levels of NOD-like receptor protein 3(NLRP3) inflammasomes, apoptosis-associated speck-like protein containing a CARD(ASC), Caspase-1 p20 Elevated levels of three inflammation-related proteins and increased activity of the Sphingosine 1-phosphate/Sphingosine 1-phosphate Receptor 2(S1P/S1P2) signaling axis.

Conclusion

Intraperitoneal injection of 10 mg/kg of LPS can successfully construct a new-onset AF model in sepsis, and NLRP3 inflammatory vesicles mediated by the S1P/S1P2 signaling axis may promote new-onset AF in sepsis.

Functional identification of soluble uric acid as an endogenous inhibitor of CD38

Excessive elevation or reduction of soluble uric acid (sUA) levels has been linked to some of pathological states, raising another subject that sUA at physiological levels may be essential for the maintenance of health. Yet, the fundamental physiological functions and molecular targets of sUA remain largely unknown. Using enzyme assays and in vitro and in vivo metabolic assays, we demonstrate that sUA directly inhibits the hydrolase and cyclase activities of CD38 via a reversible non-competitive mechanism, thereby limiting nicotinamide adenine dinucleotide (NAD+) degradation. CD38 inhibition is restricted to sUA in purine metabolism, and a structural comparison using methyl analogs of sUA such as caffeine metabolites shows that 1,3-dihydroimidazol-2-one is the main functional group. Moreover, sUA at physiological levels prevents crude lipopolysaccharide (cLPS)-induced systemic inflammation and monosodium urate (MSU) crystal-induced peritonitis in mice by interacting with CD38. Together, this study unveils an unexpected physiological role for sUA in controlling NAD+ availability and innate immunity through CD38 inhibition, providing a new perspective on sUA homeostasis and purine metabolism.

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 phosphorylation of Smad3 by CaMKIIγ leads to the hepatocyte pyroptosis under perfluorooctane sulfonate exposure

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant and accumulated in the liver of mammals. PFOS exposure is closely associated with the development of pyroptosis. Nevertheless, the underlying mechanism is unclear. We found here that PFOS induced pyroptosis in the mice liver and L-02 cells as demonstrated by activation of the NOD-like receptor protein 3 inflammasome, gasdermin D cleavage and increased release of interleukin-1β and interleukin-18. The level of cytoplasmic calcium was accelerated in hepatocytes upon exposure to PFOS. The phosphorylated/activated form of calcium/calmodulin-dependent protein kinase II (CaMKII) was augmented by PFOS in vivo and in vitro. PFOS-induced pyroptosis was relieved by CaMKII inhibitor. Among various CaMKII subtypes, we identified that CaMKIIγ was activated specifically by PFOS. CaMKIIγ interacted with Smad family member 3 (Smad3) under PFOS exposure. PFOS increased the phosphorylation of Smad3, and CaMKII inhibitor or CaMKIIγ siRNA alleviated PFOS-caused phosphorylation of Smad3. Inhibiting Smad3 activity was found to alleviate PFOS-induced hepatocyte pyroptosis. This study puts forward that CaMKIIγ-Smad3 is the linkage between calcium homeostasis disturbance and pyroptosis, providing a mechanistic explanation for PFOS-induced pyroptosis.

Silencing of TXNIP attenuates oxidative stress injury in HEI-OC1 by inhibiting the activation of NLRP3 and NF-κB

Sensorineural hearing loss (SNHL) is the most common type of hearing loss worldwide. The primary mechanism is oxidative injury to the cochlea as a result of oxidative stress. Therefore, exploring antioxidant strategies is particularly important in addressing SNHL.Thioredoxin-interacting protein (TXNIP) is an upstream target of oxidative stress-induced damage, and the NOD-like receptor protein 3 (NLRP3) and NF-κB pathways may be the main downstream molecular pathways, but this has not been reported in SNHL. Therefore, we investigated the molecular mechanism and role of TXNIP in oxidative stress injury induced by H2O2 in the HEI-OC1 auditory cells. To induce oxidative stress, HEI-OC1 cells were treated with H2O2. The TXNIP expression was measured by western blotting and Immunofluorescence. Intracellular TXNIP was knocked down using small interfering RNAs (siRNAs). Cell viability was measured by CCK8, total intracellular reactive oxygen species (ROS) by DCFH-DA, mitochondrial ROS by Mito-SOX, NLRP3, pro-caspase-1, total p65 NF-κB, and phospho-p65 NF-κB expression were measured by western blotting. Statistical analyses were performed using one-way analysis of variance, and p < 0.05 was considered statistically significant. We found that H2O2 treatment induced oxidative stress injury in HEI-OC1 cells, as evidenced by decreased cell viability and increased total intracellular and mitochondrial ROS levels (p < 0.05). TXNIP expression was elevated, and NLRP3 and NF-κB were activated (p < 0.05). Moreover, siRNA-TXINIP co-treatment reversed these changes and protected HEI-OC1 cells from oxidative stress (p < 0.05). We concluded that H2O2-induced oxidative stress in HEI-OC1 cells was alleviated by TXNIP inhibition. The finding may provide new insight into the prevention and treatment of SNHL.

Updated insights into the NLRP3 inflammasome in postoperative cognitive dysfunction: emerging mechanisms and treatments

Postoperative cognitive dysfunction (POCD) poses a significant threat to patients undergoing anesthesia and surgery, particularly elderly patients. It is characterized by diminished cognitive functions post surgery, such as impaired memory and decreased concentration. The potential risk factors for POCD include age, surgical trauma, anesthetic type, and overall health condition; however, the precise mechanisms underlying POCD remain elusive. Recent studies suggest that neuroinflammation might be a primary pathogenic factor. NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes are implicated in exacerbating POCD by promoting the release of inflammatory factors and proteins that initiate pyroptosis, further influencing the disease process. The regulation of NLRP3 inflammasome activity, including its activation and degradation, is tightly controlled through multiple pathways and mechanisms. In addition, autophagy, a protective mechanism, regulates the NLRP3 inflammasome to control the progression of POCD. This review reviews recent findings on the role of the NLRP3 inflammasome in POCD pathogenesis and discusses therapeutic strategies aimed at reducing NLRP3 sources, inhibiting cellular pyroptosis, and enhancing autophagy.