Recent advances in the mechanisms of NLRP3 inflammasome activation and its inhibitors. Cell Death Dis. 2019;10:128. [PMID: 30755589 PMCID: PMC6372664 DOI: 10.1038/s41419-019-1413-8]

Neuroprotective potential of tranilast in streptozotocin-induced sporadic Alzheimer's disease model targeting TXNIP-NLRP3 inflammasome pathway

Sporadic Alzheimer's disease (sAD) is a progressive neurodegenerative disorder characterised by oxidative stress, neuroinflammation, mitochondrial dysfunction and cerebral insulin resistance. Even though approximately 95 % of AD cases are reported as sporadic, the exact pathogenesis remains sparse. Tranilast, an analogue of tryptophan metabolite, was initially endowed as an anti-allergic agent and used in multiple inflammatory ailments. Still, the molecular mechanisms targeting sAD are yet to be investigated. In the present study, we investigated the neuroprotective potential of tranilast by performing biochemical, molecular and histopathological assessments using both in vivo and in vitro experimental sAD models. Streptozotocin (STZ; 3 mg/kg) was bilaterally injected on day 1 and 3 through the intracerebroventricular (ICV) route to Sprague Dawley rats for the in vivo model induction. Spontaneous alternation test, novel object recognition test, and passive avoidance test were performed to assess the altered behavioural patterns in animals. Furthermore, human neuroblastoma cells (SHSY5Y) were exposed to STZ (1 mM) and tranilast for 24 h to validate the in vivo results. Three weeks of tranilast (30 and 100 mg/kg, p.o.) treatment improved neurobehavioural anomalies in ICV-STZ-treated rats by halting neuroinflammation and NLRP3 inflammasome activation caused by enhanced reactive oxygen species (ROS) and thioredoxin interaction protein (TXNIP) overexpression. The phosphorylated tau (p-tau S416) level was also increased in the ICV-STZ rat's hippocampus and reversed upon tranilast treatment. A high dose of tranilast (100 mg/kg) treatment sensitised hippocampal insulin signalling in ICV-STZ-treated rats. Furthermore, in cell culture studies, 24-h tranilast (30 and 100 μM) treatment reduced the mitochondrial ROS production and attenuated inflammasome activation in STZ-treated SHSY5Y cells. In summary, the findings of the study proclaim the neuroprotective potential of tranilast in STZ induced model of sAD by modulating the TXNIP-NLRP3 inflammasome pathway.

Refractory Pleuritis in a Patient with Silicosis, Systemic Sclerosis, and Sjögren's Syndrome: Considering the Potential Role of Adjuvant-Induced Autoimmunity

BACKGROUND Silicosis, which is caused by the inhalation of crystalline silica, is known to be associated with a variety of autoimmune diseases. Recently, a new pathogenesis called autoimmune/inflammatory syndrome induced by adjuvants (ASIA) has been reported, which occurs after exposure to substances with adjuvant activity, including silica, and shares clinical features observed in several autoimmune diseases. CASE REPORT A 65-year-old man with silicosis was admitted to our hospital due to fever and chronic fatigue. Symptoms such as sicca and Raynaud's phenomenon and pleural effusion appeared as new findings on admission. Examination led to a diagnosis of systemic scleroderma (SSc) and Sjögren's syndrome (SjS). Considering that SjS was the main cause of the disease, corticosteroid therapy was initiated. However, the patient's general condition deteriorated, leading finally to his death. Silica acts as an adjuvant, inducing chronic inflammatory cytokine release. Thus, prolonged exposure to silica can contribute to the development of autoimmune diseases such as SSc and SjS. In this case, the refractory pleuritis may have been related to the pathogenesis of ASIA. ASIA is difficult to manage if the causative adjuvant cannot be eliminated. CONCLUSIONS We described a case of newly diagnosed SSc and SjS with therapy-resistant pleuritis in a patient with silicosis. Silicosis complicated with corticosteroid-resistant autoimmune disease suggests that ASIA, an adjuvant disease, is involved in the pathogenesis. Therefore, not only SSc and SjS but also the pathogenesis of ASIA should be considered in such cases. Since adjuvant exposure is a causative factor in ASIA, avoiding such exposure is crucial.

Chaperone-mediated autophagy, heat shock protein 70, and serotonin: novel targets of beta-hydroxybutyrate in HFFD/LPS-induced sporadic Alzheimer's disease model

Sporadic Alzheimer's disease (AD), which accounts for the majority of cases, is sturdily influenced by lifestyle factors such as dietary habits, obesity, and diabetes, leading to its classification as Type 3 diabetes. To model this pathological link, our AD-like model was developed by feeding Wistar male rats a high-fat diet with fructose in drinking water (HFFD) for 8 weeks, followed by a single dose of lipopolysaccharide (LPS). This group was compared with a normal control group fed a standard diet and a β-hydroxybutyrate (BHB)-treated group (125 mg/kg, p.o.), administered starting 3 h after LPS and continuing for 1 week. The results demonstrate that BHB treatment illuminated cognitive gains, as indicated by the Y-maze, Morris water maze, and novel object recognition tests. In addition, it preserved hippocampal cytoarchitecture, reduced neurodegeneration, and attenuated amyloid plaques and phosphorylated Tau deposition. Cellularly, BHB restored critical molecular mechanisms, including increased lysosomal-associated membrane protein 2A (LAMP2A) hippocampal content as the main marker of chaperone-mediated autophagy (CMA), along with the chaperon protein Hsp70. Moreover, BHB alleviated neuroinflammation by inhibiting the nucleotide-binding domain, leucine-rich-containing family, and pyrin domain-containing-3 (NLRP3) inflammasome activation alongside the downstream targets cleaved caspase-1 and IL-1β/IL-18 cytokines. BHB also reduced pyroptotic markers, caspase-11 and gasdermin-N, and microglia-induced inflammation as it shifted microglial polarization toward the neuroprotective M2 phenotype. Finally, BHB normalized hippocampal neurotransmitter levels of the inhibited acetylcholine and serotonin. These findings support BHB as a promising, multifaceted treatment for AD, highlighting the roles of CMA, Hsp70, and 5-HT in slowing disease progression and improving cognitive function.

Asthma and Cardiovascular Diseases: Uncovering Common Ground in Risk Factors and Pathogenesis

Asthma and cardiovascular diseases (CVDs) are the 2 common and complex health problems with a substantial global impact. Epidemiological studies indicate that asthma and CVDs are common, with evidence supporting their cooccurrence. Inflammation, oxidative stress, obesity, metabolic syndrome, smoking, secondhand smoke exposure, physical inactivity, and environmental exposures are all risk factors for asthma and CVDs. In addition, inflammatory and immunological pathways, autonomic dysfunction, endothelial dysfunction, thrombosis, coagulation, and common genetic risk factors contribute to the asthma-CVD relationship. Asthmatic individuals have higher morbidity and mortality rates related to CVDs and high-risk factors. Techniques such as screening for CVDs in asthma patients, pharmaceutical therapy, and lifestyle changes are critical for effectively managing these comorbid illnesses. Understanding the link between asthma and CVD is necessary for integrated and clinical management approaches to enhance patient outcomes and lessen the burden of these related diseases.

Inhibitors of inflammasome (NLRP3) signaling pathway as promising therapeutic candidates for oral cancer

Inflammasomes are complex protein assemblies responsible for regulating the development and release of proinflammatory cytokines like interleukin-1beta (IL-1β) and interleukin-18 (IL-18) against the intracellular triggers. Among these, the Nod-like receptor protein 3 (NLRP3) inflammasome stands out as the most extensively studied and well-characterized member, implicated in numerous pathological conditions. A systematic literature search was conducted on the PubMed such as PubMed, Scopus, Google Scholar database to identify peer-reviewed publications pertaining to the role of NLRP3 in oral cancer pathogenesis and its inhibitors for targeted therapy. Recent research highlights the emerging significance of the NLRP3 inflammasome in tumorigenesis, garnering attention as a potential target for anticancer therapies. This review delves into the involvement of NLRP3 in cancer development and progression, providing an in-depth overview of its activation (and inhibition) and its impact on oral cancer pathogenesis. The manuscript provides a detailed review of the natural and synthetic compounds inhibiting the NLRP3 signaling pathway, which might act as therapeutic lead molecules in oral cancer. This holds promise to overcome targeted and effective treatment options the development of novel drugs targeting the NLRP3 inflammasome-mediated mechanisms in oral cancer.

A novel regulator of NLRP3 inflammasome: Peptides

The NLRP3 inflammasome plays a crucial role as a critical regulator of the immune response and has been implicated in the pathogenesis of numerous diseases. Peptides, known for their remarkable potency, selectivity, and low toxicity, have been extensively employed in disease treatment. Recent research has unveiled the potential of peptides in modulating the activity of the NLRP3 inflammasome. This review begins by examining the structure of the NLRP3 inflammasome, encompassing NLRP3, ASC, and Caspase-1, along with the three activation pathways: canonical, non-canonical, and alternative. Subsequently, we provide a comprehensive summary of peptide modulators targeting the NLRP3 inflammasome and elucidate their underlying mechanisms. The efficacy of these modulators has been validated through in vitro and in vivo experiments on NLRP3 inflammasome regulation. Furthermore, we conduct sequence alignment of the identified peptides and investigate their binding sites on the NLRP3 protein. This work is a foundational exploration for advancing peptides as potential therapeutic agents for NLRP3-related diseases.

Loteprednol etabonate alleviates NLRP3 inflammasome-associated inflammatory diseases in mice by suppressing the transcription of IL-1β

Excessive activation of the NLRP3 inflammasome leads to cellular inflammation and tissue damage. Finding an inhibitor of its activation is urgent need for NLRP3 inflammasome-associated inflammatory diseases. In this study, we identified Loteprednol etabonate (LE), a well-known anti-inflammatory drug for ocular conditions, as a potent inhibitor of NLRP3 inflammasome activation through screening an FDA-approved drug library. In cellular models, LE significantly reduced IL-1β transcription, suppressed NLRP3 inflammasome activation, and finally inhibited the maturation and secretion of IL-1β and GSDMD-mediated pyroptosis. Mechanistic investigations showed that LE might inhibit IL-1β transcription by blocking both NF-κB and AP-1 signaling pathways. Furthermore, in mouse models of NLRP3 inflammasome-associated inflammatory diseases, including LPS-induced sepsis and DSS-induced colitis, intraperitoneal injection of LE significantly suppressed inflammatory response and improved mice survival rate. Collectively, these findings identify LE as a novel inhibitor of NLRP3 inflammasome activation, offering a promising therapeutic strategy for the treatment of NLRP3 inflammasome-associated inflammatory diseases.

Updated insights into the molecular networks for NLRP3 inflammasome activation

Over the past decade, significant advances have been made in our understanding of how NACHT-, leucine-rich-repeat-, and pyrin domain-containing protein 3 (NLRP3) inflammasomes are activated. These findings provide detailed insights into the transcriptional and posttranslational regulatory processes, the structural-functional relationship of the activation processes, and the spatiotemporal dynamics of NLRP3 activation. Notably, the multifaceted mechanisms underlying the licensing of NLRP3 inflammasome activation constitute a focal point of intense research. Extensive research has revealed the interactions of NLRP3 and its inflammasome components with partner molecules in terms of positive and negative regulation. In this Review, we provide the current understanding of the complex molecular networks that play pivotal roles in regulating NLRP3 inflammasome priming, licensing and assembly. In addition, we highlight the intricate and interconnected mechanisms involved in the activation of the NLRP3 inflammasome and the associated regulatory pathways. Furthermore, we discuss recent advances in the development of therapeutic strategies targeting the NLRP3 inflammasome to identify potential therapeutics for NLRP3-associated inflammatory diseases. As research continues to uncover the intricacies of the molecular networks governing NLRP3 activation, novel approaches for therapeutic interventions against NLRP3-related pathologies are emerging.

Role of NLRP3 inflammasome in nanoparticle adjuvant-mediated immune response

The nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome is pivotal in orchestrating the immune response induced by nanoparticle adjuvants. Understanding the intricate mechanisms underlying the activation of NLRP3 inflammasome by these adjuvants is crucial for deciphering their immunomodulatory properties. This review explores the involvement of the NLRP3 inflammasome in mediating immune responses triggered by nanoparticle adjuvants. It delves into the signaling pathways and cellular mechanisms involved in NLRP3 activation, highlighting its significance in modulating the efficacy and safety of nanoparticle-based adjuvants. A comprehensive grasp of the interplay between NLRP3 inflammasome and nanoparticle adjuvants holds promise for optimizing vaccine design and advancing immunotherapeutic strategies.

Pyroptosis in sepsis-associated acute kidney injury: mechanisms and therapeutic perspectives

Sepsis-associated acute kidney injury (S-AKI) is a severe complication characterized by high morbidity and mortality, driven by multi-organ dysfunction. Recent evidence suggests that pyroptosis, a form of programmed cell death distinct from apoptosis and necrosis, plays a critical role in the pathophysiology of S-AKI. This review examines the mechanisms of pyroptosis, focusing on inflammasome activation (e.g., NLRP3), caspase-mediated processes, and the role of Gasdermin D in renal tubular damage. We also discuss the contributions of inflammatory mediators, oxidative stress, and potential therapeutic strategies targeting pyroptosis, including inflammasome inhibitors, caspase inhibitors, and anti-inflammatory therapies. Lastly, we highlight the clinical implications and challenges in translating these findings into effective treatments, underscoring the need for personalized medicine approaches in managing S-AKI.

Mitochondrial DNA signals driving immune responses: Why, How, Where?

There has been a recent expansion in our understanding of DNA-sensing mechanisms. Mitochondrial dysfunction, oxidative and proteostatic stresses, instability and impaired disposal of nucleoids cause the release of mitochondrial DNA (mtDNA) from the mitochondria in several human diseases, as well as in cell culture and animal models. Mitochondrial DNA mislocalized to the cytosol and/or the extracellular compartments can trigger innate immune and inflammation responses by binding DNA-sensing receptors (DSRs). Here, we define the features that make mtDNA highly immunogenic and the mechanisms of its release from the mitochondria into the cytosol and the extracellular compartments. We describe the major DSRs that bind mtDNA such as cyclic guanosine-monophosphate-adenosine-monophosphate synthase (cGAS), Z-DNA-binding protein 1 (ZBP1), NOD-, LRR-, and PYD- domain-containing protein 3 receptor (NLRP3), absent in melanoma 2 (AIM2) and toll-like receptor 9 (TLR9), and their downstream signaling cascades. We summarize the key findings, novelties, and gaps of mislocalized mtDNA as a driving signal of immune responses in vascular, metabolic, kidney, lung, and neurodegenerative diseases, as well as viral and bacterial infections. Finally, we define common strategies to induce or inhibit mtDNA release and propose challenges to advance the field.

Can pyridoxine function as an anti-pyroptosis agent? A narrative review

BACKGROUND

Pyroptosis, a highly inflammatory form of programmed cell death, plays a key role in diseases such as sepsis, rheumatoid arthritis, Alzheimer's disease, and COPD. It is driven by inflammasome activation, leading to the release of pro-inflammatory cytokines. Pyridoxine (Vitamin B6), an essential micronutrient with known anti-inflammatory effects, has been suggested as a potential regulator of inflammasome activation and pyroptosis. This review examines current evidence on pyridoxine's role in modulating pyroptosis.

METHODS

A literature search was conducted in PubMed, Scopus, and Web of Science for studies published between 2014 and 2024. The search focused on pyridoxine's relationship with inflammation, inflammasomes, and pyroptosis pathways using keywords such as "pyridoxine," "Vitamin B6," "pyroptosis," "inflammasome," "caspase-1," and "gasdermin D." Both preclinical and human studies were reviewed, with emphasis on molecular mechanisms underlying pyridoxine's anti-inflammatory effects.

RESULTS

Studies consistently showed that pyridoxine reduced inflammasome activation, decreased pro-inflammatory cytokine production, and inhibited caspase-1 (CASP-1) activity, thereby suppressing pyroptosis. Human studies, though indirect, linked higher pyridoxine levels to reduced systemic inflammation, suggesting a possible anti-pyroptotic effect.

CONCLUSIONS

Pyridoxine shows potential as an anti-pyroptotic agent due to its anti-inflammatory and immunomodulatory properties. However, further well-designed clinical trials are needed to confirm its role in controlling pyroptosis, especially in diseases associated with excessive inflammasome activation.

Thermal proteome profiling reveals meltome upon NLRP3 inflammasome activation

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 (TPP). 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 (CETSA). Notably, our findings reveal that the majority of these proteins tend to cluster into distinct macromolecular complexes. Furthermore, we identify 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 TPP in exploring proteome-wide thermal stability changes during signaling transduction.

Salmonella-NLRP3 Inflammasome Crosstalk: Host Defense Activation Versus Bacterial Immune Evasion Strategies

The innate immune system plays a crucial role in defending against Salmonella infection. Inflammasomes are macromolecular complexes that assemble in response to the recognition of pathogen- or danger-associated molecular patterns. These complexes serve as signaling platforms for the activation of inflammatory Caspases, which subsequently triggers the maturation and secretion of the pro-inflammatory cytokines IL-1β and IL-18. This process also initiates pyroptosis, a highly inflammatory form of programmed cell death characterized by lytic cell lysis. Salmonella are intracellular pathogens that proliferate within epithelial cells and macrophages, posing a significant public health risk in both developed and developing countries. During Salmonella infection, the canonical NLRP3 and NLRC4 inflammasome, as well as non-canonical inflammasome, are activated. Unlike NLRC4 and non-canonical inflammasomes, which play crucial roles during intestinal infection phases, the role of NLRP3 inflammasome in resisting Salmonella infection demonstrates a higher degree of complexity and uncertainty. Nonetheless, the activation of NLRP3 inflammasome, along with the downstream innate and adaptive responses, form a robust host immune barrier against potential pathogens. Therefore, successful pathogens must evolve multiple mechanisms to circumvent or counteract these immune barriers. Here we review and discuss the mechanisms of NLRP3 inflammasome activation triggered by intracellular Salmonella, as well as the multiple strategies employed by Salmonella to avoid or delay NLRP3 inflammasome activation. A deeper understanding of how NLRP3 inflammasomes recognize Salmonella and how pathogens evade NLRP3 activation has the potential to facilitate the development of novel prevention and control measures for Salmonella infection.

Macrophage-targeting nano-formulated bicalutamide alleviates colitis by inducing MAP3K1-mediated degradation of NLRP3

The excessive activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) in macrophages has been recognized as a critical factor in the exacerbation of severe inflammatory bowel disease (IBD). Consequently, the modulation of macrophage NLRP3 activity may serve as an effective strategy for mitigating IBD. Our study has indicated that bicalutamide, a clinically administered agent, has the capacity to reduce inflammation by promoting the degradation of NLRP3 in a macrophage-specific manner. However, the therapeutic efficacy of bicalutamide in treating colitis has remained limited. In an effort to enhance the precision of NLRP3 regulation, a nano-bicalutamide system targeting macrophages has been developed, which has shown potential to significantly improve the therapeutic impact on colitis. Mechanistically, it has been found that this system degrades the NLRP3 protein through the autophagy pathway by recruiting the E3 ligase, mitogen-activated protein kinase kinase 1 (MAP3K1), and the autophagy receptor protein optineurin (OPTN). Furthermore, our findings have indicated that the degradation of macrophage NLRP3 inhibits its M1-type polarization, which in turn hinders the colitis process. The system that we have devised has demonstrated potential to address the urgent need for the treatment of colitis, as well as other diseases related to macrophage NLRP3 dysregulation.

Cardio-Rheumatic Diseases: Inflammasomes Behaving Badly

Cardio-rheumatology is an evolving and interdisciplinary field lying at the intersection of rheumatology and cardiovascular medicine that recognizes that individuals with autoimmune and inflammatory rheumatic complications have a much higher likelihood of developing cardiovascular diseases (CVDs). Inflammasomes are multiprotein complexes stimulated by the immune system after the detection of pathogens or cellular injury. Inflammasomes undergo a two-stage activation process initiated by nuclear factor (NF)-κB, subsequently playing a crucial role in innate immunity through activation of caspase 1 and the consequent release of proinflammatory cytokines such as IL-18 and IL-1β. However, a loss of control of inflammasome activation can cause inflammatory diseases in humans. Recent studies have focused on the role of inflammasomes in inflammatory cascades implicated in the pathogenesis of several diseases. Here, we review inflammasome activation, its mechanism of action, and its role in CVD. In particular, we describe the role of inflammasomes in rheumatic heart disease, Kawasaki disease, familial Mediterranean fever, ankylosing spondylitis, and rheumatoid arthritis as exemplars to illustrate pathobiological mechanisms and the potential for targeting inflammasomes for therapeutic benefit.

NLRP3 inflammasomes pathway: a key target for Metformin

Nucleotide-binding oligomerization domain, Leucine rich Repeat and Pyrin domain containing 3 (NLRP3) is a signaling pathway that is involved in inflammatory cascades, cell survival and the immune response. NLRP3 is activated by cellular damage, oxidative stress, and other factors that stimulate the immune system. Stimulation of NLRP3 induces inflammatory reactions and the production of inflammatory cytokines. These inflammatory mediators are implicated in several diseases. Metformin (MET) is an anti-hyperglycemia agent that is extensively used in clinical practice worldwide due to its high efficiency, safety profile, and affordable price. MET is the only member of biguanide class that is used in clinical practice and a potent AMP-activated protein kinase (AMPK) agonist with proven anti-inflammatory characteristics. Due to its anti-inflammatory properties, MET is considered to be effective against diseases that have an inflammatory background, and the NLRP3 pathway is involved in the pathophysiology of these disorders. In this review, we have evaluated the evidence if MET can affect this pathway and its utility for future therapeutic approaches.

Alloferon Mitigates LPS-Induced Endometritis by Attenuating the NLRP3/CASP1/IL-1β/IL-18 Signaling Cascade

Endometritis is an inflammatory reaction of the uterine lining that can lead to infertility. Alloferon, a linear non-glycosylated oligopeptide, has been recognized for its potent anti-inflammatory and immunomodulatory effects. In light of these attributes, this study aims to explore the potential therapeutic effects of alloferon in alleviating endometrial inflammation induced by lipopolysaccharide (LPS), while elucidating the underlying protective mechanisms. Two conditions representing pre- and post-menopause states were simulated using an ovariectomized (Ovx) murine model. The findings underscore alloferon's remarkable capacity to alleviate cardinal signs of endometritis, including redness, swelling, and congestion, while concurrently restoring the structural integrity of the endometrial tissue. Moreover, alloferon effectively modulates the expression of key inflammatory mediators, such as nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3), cysteine aspartate-specific protease 1 (CASP1), interleukin-1β (IL-1β), and interleukin-18 (IL-18). In vitro experiments were conducted to further corroborate and validate these findings. In conclusion, alloferon shows promising potential in mitigating LPS-induced inflammation by attenuating the NLRP3/CASP1/IL-1β/IL-18 signaling cascade.

ATG16L1 restrains macrophage NLRP3 activation and alveolar epithelial cell injury during septic lung injury

BACKGROUND

The lung is the organ most commonly affected by sepsis. Additionally, acute lung injury (ALI) resulting from sepsis is a major cause of death in intensive care units. Macrophages are essential for maintaining normal lung physiological functions and are implicated in various pulmonary diseases. An essential autophagy protein, autophagy-related protein 16-like 1 (ATG16L1), is crucial for the inflammatory activation of macrophages.

METHODS

ATG16L1 expression was measured in lung from mice with sepsis. ALI was induced in myeloid ATG16L1-, NLRP3- and STING-deficient mice by intraperitoneal injection of lipopolysaccharide (LPS, 10 mg/kg). Using immunofluorescence and flow cytometry to assess the inflammatory status of LPS-treated bone marrow-derived macrophages (BMDMs). A co-culture system of BMDMs and MLE-12 cells was established in vitro.

RESULTS

Myeloid ATG16L1-deficient mice exhibited exacerbated septic lung injury and a more intense inflammatory response following LPS treatment. Mechanistically, ATG16L1-deficient macrophages exhibited impaired LC3B lipidation, damaged mitochondria and reactive oxygen species (ROS) accumulation. These abnormalities led to the activation of NOD-like receptor family pyrin domain-containing protein 3 (NLRP3), subsequently enhancing proinflammatory response. Overactivated ATG16L1-deficient macrophages aggravated the damage to alveolar epithelial cells and enhanced the release of double-stranded DNA (dsDNA), thereby promoting STING activation and subsequent NLRP3 activation in macrophages, leading to positive feedback activation of macrophage NLRP3 signalling. Scavenging mitochondrial ROS or inhibiting STING activation effectively suppresses NLRP3 activation in macrophages and alleviates ALI. Furthermore, overexpression of myeloid ATG16L1 limits NLRP3 activation and reduces the severity of ALI.

CONCLUSIONS

Our findings reveal a new role for ATG16L1 in regulating macrophage NLRP3 feedback activation during sepsis, suggesting it as a potential therapeutic target for treating sepsis-induced ALI.

KEY POINTS

Myeloid-specific ATG16L1 deficiency exacerbates sepsis-induced lung injury. ATG16L1-deficient macrophages exhibit impaired LC3B lipidation and ROS accumulation, leading to NLRP3 inflammasome activation. Uncontrolled inflammatory responses in ATG16L1-deficient macrophages aggravate alveolar epithelial cell damage. Alveolar epithelial cells release dsDNA, activating the cGAS-STING-NLRP3 signaling pathway, which subsequently triggers a positive feedback activation of NLRP3. Overexpression of ATG16L1 helps mitigate lung tissue inflammation, offering a novel therapeutic direction for sepsis-induced lung injury.

Hypocrellin A from an ethnic medicinal fungus protects against NLRP3-driven gout in mice by suppressing inflammasome activation

Abnormal activation of NLRP3 inflammasome causes the progression of gout, and no small-molecule inhibitor of NLRP3 has been approved yet for clinical use. In this study we established a nigericin-induced inflammasome activation cell model for screening of a natural product library by measuring IL-1β secretion in cell supernatants. Among 432 compounds tested, we found that hypocrellin A (HA), one of the major active components of a traditional ethnic medicinal fungus Hypocrella bambusea in the Northwest Yunnan of China, exhibited the highest inhibition on IL-1β production (IC50 = 0.103 μM). In PMA-primed THP-1 cells or bone marrow derived macrophages (BMDMs) treated with multiple stimuli (nigericin, ATP or MSU), HA dose-dependently suppressed the activation of NLRP3 inflammasome, reducing the subsequent release of inflammatory cytokines and LDH. Furthermore, the suppression of inflammasome activation by HA was specific to NLRP3, but not to AIM2 or NLRC4. In LPS-primed BMDMs treated with nigericin, HA inhibited ASC oligomerization and speckle formation, and blocked the NLRP3-NEK7 interaction during inflammasome assembly without influencing the priming stage. Moreover, we demonstrated that HA directly bound to the NACHT domain of NLRP3, and that Arg578 and Glu629 were the critical residues for HA binding to NLRP3. In MSU-induced peritonitis and acute gouty arthritis mouse models, administration of HA (10 mg/kg, i.p., once or twice daily) effectively suppressed the inflammatory responses mediated by NLRP3 inflammasome. We conclude that HA is a broad-spectrum and specific NLRP3 inhibitor, and a valuable lead compound to develop novel therapeutic inhibitors against NLRP3-driven diseases. This study also elucidates the anti-inflammation mechanisms and molecular targets of HA, a major active component in medicinal fungus Hypocrella bambusea that has been long used by Chinese ethnic groups.

Role of gasdermins in chronic kidney disease

Gasdermins (GSDMs), functioning as membrane perforating proteins, can be activated by canonical inflammasomes, noncanonical inflammasomes, as well as non-inflammasomes, leading to cell pyroptosis and the subsequent release of inflammatory mediators. Increasing evidence has implicated that GSDMs are associated with chronic kidney disease (CKD), including diabetes nephropathy, lupus nephritis, obstructive nephropathy, and crystalline nephropathy. This review centers on the role of GSDMs-mediated pyroptosis in the pathogenesis of CKD, providing novel ideas for enhancing the prognosis and therapeutic strategies of CKD.

NEDD4 E3 ligase-catalyzed NAMPT ubiquitination and autophagy activation are essential for pyroptosis-independent NAMPT secretion in human monocytes

NAMPT is an important intracellular metabolic enzyme (iNAMPT) regulating the NAD+ salvage pathway. However, increased cellular stress (infection, inflammation, hypoxia) promotes the secretion of extracellular NAMPT (eNAMPT), a TLR4 ligand and damage-associated molecular pattern protein (DAMP) that directly drives amplification of innate immune-mediated inflammatory, fibrotic, and neoplastic responses to influence disease severity. We sought to examine the mechanisms underlying pyroptotic eNAMPT release from human monocytic THP-1 cells, evoked by Nigericin, and non-pyroptotic eNAMPT secretion elicited by lipopolysaccharide (LPS). Our data indicate eNAMPT secretion/release requires NLRP3 inflammasome activation with substantial attenuation by either NLRP3 inhibition (MCC-950) or targeted genetic deletion of key inflammasome components, including NLRP3, caspase-1, or gasdermin D (GSDMD). Pyroptosis-associated eNAMPT release involved cleavage of the pore-forming GSDMD protein resulting in plasma membrane rupture (PMR) whereas non-pyroptotic LPS-induced eNAMPT secretion involved neither GSDMD cleavage nor PMR, verified utilizing non-cleavable GSDMD mutant constructs. LPS-induced eNAMPT secretion, however, was highly dependent upon NAMPT ubiquitination catalyzed by a complex containing the NEDD4 E3 ligase, Hsp90 (a selective chaperone), and intact GSDMD verified by enzymatic inhibition or silencing of NEDD4, GSDMD, or Hsp90. NAMPT ubiquitination and secretion involves autophagy activation as super-resolution microscopy analyses demonstrate NAMPT co-localization with autophagosome marker LC3B and eNAMPT secretion was significantly reduced by targeted ATG5 and ATG7 inhibition, critical components of the autophagy E3-like complex. These studies provide key insights into eNAMPT secretion that may accelerate the development of therapeutic strategies that address unmet therapeutic needs in inflammatory, fibrotic and neoplastic disorders.

Role of toll-like receptors in post-COVID-19 associated neurodegenerative disorders?

In the intricate realm of interactions between hosts and pathogens, Toll-like receptors (TLRs), which play a crucial role in the innate immune response, possess the ability to identify specific molecular signatures. This includes components originating from pathogens such as SARS-CoV-2, as well as the resulting damage-associated molecular patterns (DAMPs), the endogenous molecules released after cellular damage. A developing perspective suggests that TLRs play a central role in neuroinflammation, a fundamental factor in neurodegenerative conditions like Alzheimer's and Parkinson's disease (PD). This comprehensive review consolidates current research investigating the potential interplay between TLRs, their signaling mechanisms, and the processes of neurodegeneration following SARS-CoV-2 infection with an aim to elucidate the involvement of TLRs in the long-term neurological complications of COVID-19 and explore the potential of targeting TLRs as a means of implementing intervention strategies for the prevention or treatment of COVID-19-associated long-term brain outcomes.

The Role of IL-6 in Ischemic Stroke

The pathophysiology of a stroke is a complex process involving oxidative stress and inflammation. As a result of the actions of reactive oxygen species (ROS), not only does vascular damage occur, but the brain tissue is also damaged. It is a dynamic process, induced by a cellular-molecular immune response, focused on the development of an immediate reaction. During ischemia, inflammatory mediators are released, among which IL-6 plays a particularly important role in the acute phase of a stroke. Recently, a lot of attention has been devoted to this pleiotropic pro-inflammatory cytokine, which enhances the migration of leukocytes and is controlled by chemokines and the expression of adhesion handlers. The impact of IL-6 on the severity of neurological treatment and on patient prognosis in AIS is of interest to many researchers. More and more data indicate that it may be a reliable prognostic factor in strokes.

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.

Engineered Drug-Amphiphile Conjugate Nanoparticles for Targeted Inhibition of AQP4-Mediated NLRP3 Inflammasome Signaling in Collagen-Induced Rheumatoid Arthritis

Aquaporins (AQPs) are transmembrane proteins that transport water, small solutes, and molecules across cell membranes. Studies have reported the role of AQPs in the activation, migration, and proliferation of immune cells, thus modulating the pathogenesis of autoimmune disease. In joints, the enhanced AQP4 expression exaggerates pathological changes like hydrarthrosis, acidosis, and hyperosmotic stress-inducing dysfunction of the articular chondrocytes, leading to articular cartilage destruction in collagen-induced arthritis (CIA). Acetazolamide (AZM), a sulfonamide carbonic anhydrase inhibitor of AQP4, reversibly decreases water permeability through AQP4 and is a potential molecule for targeting AQP4 in the CIA. However, its low solubility and low bioavailability limit its therapeutic effectiveness. Therefore, in this study, we have synthesized a polyphenol drug (gallic acid) (GA) and an amphiphile (glycerol monostearate) (GMS) conjugate to self-assemble into nanoparticles and encapsulated with AZM. Apart from AZM, GA is known for its antioxidant and anti-inflammatory properties. Therefore, intra-articular injection of AZM@GA-GMS NPs efficiently downregulates the expression of AQP4 and associated NLRP3 inflammasome activation. Moreover, the NPs are cytocompatible and showed enzyme-responsive drug release and thus offer a promising therapeutic strategy for RA by inhibiting AQP4-mediated inflammatory pathways. This opens up an avenue for treatment for RA.

Ubiquitin Ligases in Control: Regulating NLRP3 Inflammasome Activation

Ubiquitin ligases play pivotal roles in the regulation of NLR family pyrin domain containing 3 (NLRP3) inflammasome activation, a critical process in innate immunity and inflammatory responses. This review explores the intricate mechanisms by which various E3 ubiquitin ligases exert both positive and negative influences on NLRP3 inflammasome activity through diverse post-translational modifications. Negative regulation of NLRP3 inflammasome assembly is mediated by several E3 ligases, including F-box and leucine-rich repeat protein 2 (FBXL2), tripartite motif-containing protein 31 (TRIM31), and Casitas B-lineage lymphoma b (Cbl-b), which induce K48-linked ubiquitination of NLRP3, targeting it for proteasomal degradation. Membrane-associated RING-CH 7 (MARCH7) similarly promotes K48-linked ubiquitination leading to autophagic degradation, while RING finger protein (RNF125) induces K63-linked ubiquitination to modulate NLRP3 function. Ariadne homolog 2 (ARIH2) targets the nucleotide-binding domain (NBD) domain of NLRP3, inhibiting its activation, and tripartite motif-containing protein (TRIM65) employs dual K48 and K63-linked ubiquitination to suppress inflammasome assembly. Conversely, Pellino2 exemplifies a positive regulator, promoting NLRP3 inflammasome activation through K63-linked ubiquitination. Additionally, ubiquitin ligases influence other components critical for inflammasome function. TNF receptor-associated factor 3 (TRAF3) mediates K63 polyubiquitination of apoptosis-associated speck-like protein containing a CARD (ASC), facilitating its degradation, while E3 ligases regulate caspase-1 activation and DEAH-box helicase 33 (DHX33)-NLRP3 complex formation through specific ubiquitination events. Beyond direct inflammasome regulation, ubiquitin ligases impact broader innate immune signaling pathways, modulating pattern-recognition receptor responses and dendritic cell maturation. Furthermore, they intricately control NOD1/NOD2 signaling through K63-linked polyubiquitination of receptor-interacting protein 2 (RIP2), crucial for nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) activation. Furthermore, we explore how various pathogens, including bacteria, viruses, and parasites, have evolved sophisticated strategies to hijack the host ubiquitination machinery, manipulating NLRP3 inflammasome activation to evade immune responses. This comprehensive analysis provides insights into the molecular mechanisms underlying inflammasome regulation and their implications for inflammatory diseases, offering potential avenues for therapeutic interventions targeting the NLRP3 inflammasome. In conclusion, ubiquitin ligases emerge as key regulators of NLRP3 inflammasome activation, exhibiting a complex array of functions that finely tune immune responses. Understanding these regulatory mechanisms not only sheds light on fundamental aspects of inflammation but also offers potential therapeutic avenues for inflammatory disorders and infectious diseases.

SUMOylation regulates GSDMD stability and pyroptosis

Various post-translational modifications (PTMs), such as palmitoylation, acetylation, and ubiquitination, have been shown to regulate pyroptosis. However, the role of small ubiquitin-like modifier (SUMO) modification, known as SUMOylation, in regulating GSDMD activity and pyroptosis remains unclear. Here, we demonstrate that inhibition of SUMOylation reduces inflammatory pyroptosis by downregulating GSDMD expression. Identification of key SUMOylation sites on GSDMD-K177, is critical for regulates pyroptosis. Furthermore, we identify SENP3 as a critical deSUMOylating enzyme that binds to GSDMD, suppressing GSDMD SUMO modification, which destabilizes GSDMD and inhibits LDH secretion. These findings highlight the role of SUMOylation in GSDMD mediated-pyroptosis, suggesting SUMO inhibitors as potential therapies for inflammatory diseases.

Shared molecular, cellular, and environmental hallmarks in cardiovascular disease and cancer: Any place for drug repurposing?

Cancer and cardiovascular disease (CVD) are the 2 biggest killers worldwide. Specific treatments have been developed for the 2 diseases. However, mutual therapeutic targets should be considered because of the overlap of cellular and molecular mechanisms. Cancer research has grown at a fast pace, leading to an increasing number of new mechanistic treatments. Some of these drugs could prove useful for treating CVD, which realizes the concept of cancer drug repurposing. This review provides a comprehensive outline of the shared hallmarks of cancer and CVD, primarily ischemic heart disease and heart failure. We focus on chronic inflammation, altered immune response, stromal and vascular cell activation, and underlying signaling pathways causing pathological tissue remodeling. There is an obvious scope for targeting those shared mechanisms, thereby achieving reciprocal preventive and therapeutic benefits. Major attention is devoted to illustrating the logic, advantages, challenges, and viable examples of drug repurposing and discussing the potential influence of sex, gender, age, and ethnicity in realizing this approach. Artificial intelligence will help to refine the personalized application of drug repurposing for patients with CVD. SIGNIFICANCE STATEMENT: Cancer and cardiovascular disease (CVD), the 2 biggest killers worldwide, share several underlying cellular and molecular mechanisms. So far, specific therapies have been developed to tackle the 2 diseases. However, the development of new cardiovascular drugs has been slow compared with cancer drugs. Understanding the intersection between pathological mechanisms of the 2 diseases provides the basis for repurposing cancer therapeutics for CVD treatment. This approach could allow the rapid development of new drugs for patients with CVDs.

The cellular and molecular cardiac tissue responses in human inflammatory cardiomyopathies after SARS-CoV-2 infection and COVID-19 vaccination

Myocarditis, characterized by inflammatory cell infiltration, can have multiple etiologies, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection or, rarely, mRNA-based coronavirus disease 2019 (COVID-19) vaccination. The underlying cellular and molecular mechanisms remain poorly understood. In this study, we performed single-nucleus RNA sequencing on left ventricular endomyocardial biopsies from patients with myocarditis unrelated to COVID-19 (Non-COVID-19), after SARS-CoV-2 infection (Post-COVID-19) and after COVID-19 vaccination (Post-Vaccination). We identified distinct cytokine expression patterns, with interferon-γ playing a key role in Post-COVID-19, and upregulated IL16 and IL18 expression serving as a hallmark of Post-Vaccination myocarditis. Although myeloid responses were similar across all groups, the Post-Vaccination group showed a higher proportion of CD4+ T cells, and the Post-COVID-19 group exhibited an expansion of cytotoxic CD8+ T and natural killer cells. Endothelial cells showed gene expression changes indicative of vascular barrier dysfunction in the Post-COVID-19 group and ongoing angiogenesis across all groups. These findings highlight shared and distinct mechanisms driving myocarditis in patients with and without a history of SARS-CoV-2 infection or vaccination.

NLRP3 and AIM2 inflammasomes exacerbate the pathogenic Th17 cell response to eggs of the helminth Schistosoma mansoni

Infection with the helminth Schistosoma mansoni can cause exacerbated morbidity and mortality via a pathogenic host CD4 T cell-mediated immune response directed against parasite egg antigens, with T helper (Th) 17 cells playing a major role in the development of severe granulomatous hepatic immunopathology. The role of inflammasomes in intensifying disease has been reported; however, neither the types of caspases and inflammasomes involved, nor their impact on the Th17 response are known. Here we show that enhanced egg-induced IL-1β secretion and pyroptotic cell death required both caspase-1 and caspase-8 as well as NLRP3 and AIM2 inflammasome activation. Schistosome genomic DNA activated AIM2, whereas reactive oxygen species, potassium efflux and cathepsin B, were the major activators of NLRP3. NLRP3 and AIM2 deficiency led to a significant reduction in pathogenic Th17 responses, suggesting their crucial and non-redundant role in promoting inflammation. Additionally, we show that NLRP3- and AIM2-induced IL-1β suppressed IL-4 and protective Type I IFN (IFN-I) production, which further enhanced inflammation. IFN-I signaling also curbed inflammasome- mediated IL-1β production suggesting that these two antagonistic pathways shape the severity of disease. Lastly, Gasdermin D (Gsdmd) deficiency resulted in a marked decrease in egg-induced granulomatous inflammation. Our findings establish NLRP3/AIM2-Gsdmd axis as a central inducer of pathogenic Th17 responses which is counteracted by IFN-I pathway in schistosomiasis.

Stress-experienced monocytes/macrophages lose anti-inflammatory function via β2-adrenergic receptor in skin allergic inflammation

BACKGROUND

Psychological stress can exacerbate the development of allergies; however, the underlying mechanisms remain poorly understood. IgE-mediated cutaneous allergic inflammation (IgE-CAI) is a basophil-dependent skin allergy with eosinophil infiltration at inflammatory sites. Its resolution involves anti-inflammatory programmed death ligand 2 (PD-L2)-positive macrophages.

OBJECTIVE

This study sought to elucidate the cellular and molecular mechanisms by which psychological stress exacerbates IgE-CAI.

METHODS

Neural tissue involved in stress-induced IgE-CAI exacerbation was identified by performing denervation and brain destruction experiments in mice. Immune cell transplantation, RNA sequencing, flow cytometry, and ELISA were used to identify and characterize immune cells with stress-altered functioning, followed by identification of key factors involved in IgE-CAI exacerbation.

RESULTS

Stress-induced exacerbation of IgE-CAI was found to be sympathetic and β2-adrenergic receptor (Adrb2)-dependent. Adoptive transfer experiments revealed that stress diminished the anti-inflammatory functions of PD-L2-positive macrophages through Adrb2, exacerbating the inflammation. RNA sequencing analysis indicated that PD-L2-positive macrophages in stressed mice exhibit reduced expression of efferocytosis-related genes, including Gas6 and MerTK. Consequently, the efferocytic capacity of these macrophages decreased, resulting in increased numbers of dead cells in the lesions. The exacerbation and upregulation of Ccl24 expression in IgE-CAI skin lesions were countered by a Caspase-1 inhibitor.

CONCLUSIONS

Psychological stress diminishes the efferocytotic capacity of PD-L2-positive macrophages, causing an accumulation of dead cells. This, in turn, heightens eosinophil infiltration through Caspase-1-dependent production of CCL24, exacerbating IgE-CAI.

A New Perspective on the Prediction and Treatment of Stroke: The Role of Uric Acid

Stroke, a major cerebrovascular disease, has high morbidity and mortality. Effective methods to reduce the risk and improve the prognosis are lacking. Currently, uric acid (UA) is associated with the pathological mechanism, prognosis, and therapy of stroke. UA plays pro/anti-oxidative and pro-inflammatory roles in vivo. The specific role of UA in stroke, which may have both neuroprotective and damaging effects, remains unclear. There is a U-shaped association between serum uric acid (SUA) levels and ischemic stroke (IS). UA therapy provides neuroprotection during reperfusion therapy for acute ischemic stroke (AIS). Urate-lowering therapy (ULT) plays a protective role in IS with hyperuricemia or gout. SUA levels are associated with the cerebrovascular injury mechanism, risk, and outcomes of hemorrhagic stroke. In this review, we summarize the current research on the role of UA in stroke, providing potential targets for its prediction and treatment.

Strategic Mutations in Designer Native Peptides Combat NLRP3 Inflammasome Activation in Neurodegenerative Disorders

Nucleotide-binding oligomerization domain (NOD)-, leucine-rich repeat (LRR)-, and pyrin domain (PYD)-containing protein 3 (NLRP3) form an inflammasome by assembling with apoptosis-associated speck-like protein containing a CARD (ASC) and procaspase-1 that plays a pivotal role in various neurodegenerative diseases such as Alzheimer's and Parkinson diseases. We designed native peptides derived from the PYDs of NLRP3 and ASC based on their interfacial interaction to inhibit NLRP3 inflammasome formation. Screening revealed that NP3, derived from NLRP3, inhibits inflammasome activation. Furthermore, a strategic mutation (F → L) in native peptide NP3 results in MNP2 that selectively binds to PYD of ASC with nanomolar affinity, inhibiting NLRP3 inflammasome formation, interleukin-1β (IL-1β) release, and caspase-1 maturation. MNP2 also reduced potassium (K) and chloride (Cl) ion efflux, key signals in NLRP3 activation, and prevented mitochondrial damage and reactive oxygen species (ROS) production. MNP2 significantly reduced NLRP3 inflammasome formation in neurodegenerative conditions triggered by amyloid-β (Aβ), Tau, and α-Synuclein (α-Syn), suggesting a promising therapeutic strategy for NLRP3-related inflammatory diseases, including neurodegenerative disorders.

Plant-derived compounds and neurodegenerative diseases: Different mechanisms of action with therapeutic potential

Neurodegenerative diseases are a group of disorders characterized by progressive degeneration of discrete groups of neurons causing severe disability. The main risk factor is age, hence their incidence is rapidly increasing worldwide due to the rise in life expectancy. Although the causes of the disease are not identified in about 90% of the cases, in the last decades there has been great progress in understanding the basis for neurodegeneration. Different pathological mechanisms including oxidative stress, mitochondrial dysfunction, alteration in proteostasis and inflammation have been addressed as important contributors to neuronal death. Despite our better understanding of the pathophysiology of these diseases, there is still no cure and available therapies only provide symptomatic relief. In an effort to discover new therapeutic approaches, natural products have aroused interest among researchers given their structural diversity and wide range of biological activities. In this review, we focus on three plant-derived compounds with promising neuroprotective potential that have been traditionally used by folk medicine: the flavonoid quercetin (QCT), the phytocannabinoid cannabidiol (CBD)and the tryptamine N,N-dimethyltryptamine (DMT). These compounds exert neuroprotective effects through different mechanisms of action, some overlapping, but each demonstrating a principal biological activity: QCT as an antioxidant, CBD as an anti-inflammatory, and DMT as a promoter of neuroplasticity. This review summarizes current knowledge on these activities, potential therapeutic benefits of these compounds and their limitations as candidates for neuroprotective therapies. We envision that treatments with QCT, CBD, and DMT could be effective either when combined or when targeting different stages of these diseases.

Microbial Trojan Horses: Virulence Factors as Key Players in Neurodegenerative Diseases

Changes in population demographics indicate that the elderly population will reach 2.1 billion worldwide by 2050. In parallel, there will be an increase in neurodegenerative diseases such as Alzheimer's and Parkinson's. This review explores dysbiosis occurring in these pathologies and how virulence factors contribute to the worsening or development of clinical conditions, and it summarizes existing and potential ways to combat microorganisms related to these diseases. Microbiota imbalances can contribute to the progression of neurodegenerative diseases by increasing intestinal permeability, exchanging information through innervation, and even acting as a Trojan horse affecting immune cells. The microorganisms of the microbiota produce virulence factors to protect themselves from host defenses, many of which contribute to neurodegenerative diseases. These virulence factors are expressed according to the genetic composition of each microorganism, leading to a wide range of factors to be considered. Among the main virulence factors are LPS, urease, curli proteins, amyloidogenic proteins, VacA, and CagA. These factors can also be packed into bacterial outer membrane vesicles, which transport proteins, RNA, and DNA, enabling distal communication that impacts various diseases, including Alzheimer's and Parkinson's.

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.

Therapeutic Potential of Gasdermin D-Mediated Myocardial Pyroptosis in Ischaemic Heart Disease: Expanding the Paradigm From Bench to Clinical Insights

Ischaemic heart disease (IHD) remains a leading cause of global morbidity and mortality. One significant contributor to the pathology of IHD is the excessive release of inflammatory mediators during the disease progression. Pyroptosis is a form of programmed cell death (PCD) triggered by the activation of inflammasomes and caspase 1. The activation of inflammatory caspase 1 proteolytically cleaves gasdermin D (GSDMD) to the activated form amino acid terminus (GSDMD-NT), leading to disruption of the plasma membrane. This cascade of events is considered the canonical pathway of pyroptosis. IHD also caused oxidative stress, thereby triggering noncanonical pyroptosis via the activation of caspases 4/5/11. Previous studies have provided compelling evidence of the close relationship between pyroptosis and the aetiology of IHD (e.g., acute myocardial infarction, myocardial ischaemia and reperfusion injury and chronic myocardial infarction), as well as the association of pyroptosis with unfavourable clinical outcomes. Several interventions aimed at targeting pyroptosis have demonstrated promising therapeutic benefits against IHD-related pathologies. This review provides mechanistic insights into the roles of pyroptosis in IHD from in vitro, in vivo and clinical perspectives. In-depth understanding into this area could also pave the way for the future development of novel therapeutic strategies targeting pyroptosis in IHD.

Metabolic Reprogramming of Macrophages by Biomimetic Melatonin-Loaded Liposomes Effectively Attenuates Acute Gouty Arthritis in a Mouse Model

Gouty arthritis is characterized by an acute inflammatory response triggered by monosodium urate (MSU) crystals deposited in the joints and periarticular tissues. Current treatments bring little effects owing to serious side effects, necessitating the exploration of new and safer therapeutic options. Macrophages play a critical role in the initiation, progression, and resolution of acute gout, with the cellular profiles closely linked to their activation and polarization. This suggests that metabolic regulation can be of significance in managing gouty inflammation. In this study, it is demonstrated that melatonin, a natural hormone, modulates the metabolic remodeling of inflammatory macrophages by shifting their metabolism from glycolysis to oxidative phosphorylation, further altering functions of the pathogenic macrophage. To improve melatonin delivery to the inflamed sites, macrophage membrane-coated melatonin-loaded liposomes (MLT-MLP) are developed. Benefiting from the inflammation-homing characteristic of macrophage membrane, such engineered liposomes effectively target the inflamed site and demonstrate potent anti-inflammatory effects, achieving an enhanced amelioration of acute gouty arthritis. In conclusion, this study proposes a novel strategy aimed at metabolic reprogramming of macrophages to attenuate the pathological injuries in acute gout, providing a potential therapeutic strategy of gout-associated diseases, especially gouty arthritis.

Triptolide attenuates LPS-induced chondrocyte inflammation by inhibiting inflammasome activation via the Wnt/β-catenin and NF-κB signaling pathways

Osteoarthritis (OA) is a common form of arthritis characterized by subchondral bone proliferation and articular cartilage degeneration. Recently, the Nod-like receptor pyrin domain 3 (NLRP3) inflammasome has gained attention due to its association with synovial inflammation in OA. Triptolide (TP), known for its immunosuppressive and anti-inflammatory effects, has been studied in various diseases. However, the specific impact of TP on OA and its underlying mechanism remains largely unexplored. In this study, chondrocytes were treated with a specific concentration of TP, and subsequent analysis through Western blotting and immunofluorescence staining revealed decreased expression levels of MMP-13, NLRP3, Caspase-1, ASC, β-catenin, p-p65, and IκB compared to the model group. ELISA results demonstrated significantly lower levels of IL-1β, IL-18, and TNF-α in the TP treatment group compared to the model group. In addition, triptolide ameliorates the degradation of the extracellular matrix (ECM) by enhancing the expression of collagen-II. In conclusion, our findings suggest that TP exhibits anti-inflammatory effects on chondrocytes in the presence of LPS-induced inflammation by inhibiting the activation of the NLRP3 inflammasome via the Wnt/β-catenin and NF-κB pathway. These results contribute to a better understanding of TP's potential therapeutic benefits in managing OA.

Research Progress in the Molecular Mechanism of NLRP3 Inflammasome in Alzheimer's Disease and Regulation by Natural Plant Products

Alzheimer's disease (AD) is a prominent neurodegenerative disorder affecting the central nervous system in the elderly. Current understanding of AD primarily centers on the gradual decline in cognitive and memory functions, believed to be influenced by factors including mitochondrial dysfunction, β-amyloid aggregation, and neuroinflammation. Emerging research indicates that neuroinflammation plays a significant role in the development of AD, with the inflammasome potentially mediating inflammatory responses that contribute to neurodegeneration. Recent studies in AD pathology have identified a novel form of inflammasome referred to as NOD-like receptor pyrin domain-containing 3 (NLRP3) inflammasome. Pathological alterations closely associated with NLRP3 inflammasome activation have been observed in the brain tissues of AD patients, transgenic mice, and in vitro neurocyte models. Numerous studies have demonstrated the potent neuroprotective properties of natural plant products (NPPs) against NLRP3 inflammasome-mediated AD pathology. This review provides a comprehensive examination of the NLRP3 inflammasome, its involvement in AD pathology, and the mechanisms underlying the therapeutic effects of NPP targeting the NLRP3 inflammasome.

Brain-derived textiloma post glioblastoma resection and application of oxidized regenerated cellulose: A pilot, bedside-to-bench, translational study

Oxidized regenerated cellulose (ORC; marketed as Surgicel® and Tabotamp®) is routinely used as an intraoperative hemostatic agent. Rarely, residual ORC has been associated with a foreign body reaction generating cystic or granulomatous lesions (i.e., textilomas) at the surgical site. Here, we report a bedside-to-bench, translational report of an intracranial mass after neurosurgical resection of glioblastoma with ORC application. As part of patient care, we performed magnetic resonance imaging and histopathological analysis of the mass. We then performed in vitro studies to evaluate the effect of ORC on cytokine production and viability of BV-2 murine microglial cells by using quantitative PCR along with live cell microscopy and crystal violet staining, respectively. Magnetic resonance imaging demonstrated a recurrent mass pressing on the adjacent right ventricle, which was removed in a second surgery for diagnostic and therapeutic purposes. Unexpectedly, histopathological examination of the resected mass revealed abundant ORC arising from the site with inflammation, microglial activation, and collagenization. Mechanistically, we show an ORC-induced modest increase in inflammatory cytokines with a subsequent decrease in microglial cell viability. These findings suggest that ORC may mediate microglial immune response and viability, and serve to raise awareness and guide interpretation of post-treatment surveillance imaging findings in the instance of foreign body reaction.

New perspectives on microbiome-dependent gut-brain pathways for the treatment of depression with gastrointestinal symptoms: from bench to bedside

Patients with depression are more likely to have chronic gastrointestinal (GI) symptoms than the general population, but such symptoms are considered only somatic symptoms of depression and lack special attention. There is a chronic lack of appropriate diagnosis and effective treatment for patients with depression accompanied by GI symptoms, and studying the association between depression and GI disorders (GIDs) is extremely important for clinical management. There is growing evidence that depression is closely related to the microbiota present in the GI tract, and the microbiota-gut-brain axis (MGBA) is creating a new perspective on the association between depression and GIDs. Identifying and treating GIDs would provide a key opportunity to prevent episodes of depression and may also improve the outcome of refractory depression. Current studies on depression and the microbially related gut-brain axis (GBA) lack a focus on GI function. In this review, we combine preclinical and clinical evidence to summarize the roles of the microbially regulated GBA in emotions and GI function, and summarize potential therapeutic strategies to provide a reference for the study of the pathomechanism and treatment of depression in combination with GI symptoms.

The Tan-Re-Qing Capsule mitigates acute lung injury by suppressing the NLRP3 inflammasome and MAPK/NF-κB signaling pathways

OBJECTIVE

The Tan-Re-Qing Capsule (TRQC), a traditional Chinese medicine (TCM) preparation, has been historically utilized in treating acute lung injury (ALI) and COVID-19-induced pulmonary diseases. This study aimed to explore the effect and underlying mechanisms of TRQC in lipopolysaccharide (LPS)-induced ALI models.

METHODS

The changes of acute lung injury and inflammatory response were observed after TRQC treatment of the LPS-induced ALI mouse model. Based on active compounds in TRQC and network pharmacology analysis, potential targeting signals were identified. The effects of TRQC on signaling in LPS-stimulated BMDMs were investigated. Additionally, the defecatory status of mice and the mechanism of Cl- secretion in HBE cells and T84 colonic epithelial cells were examined.

RESULTS

TRQC exhibited a notable amelioration of inflammatory injuries in ALI mice. Utilizing a systems-pharmacology approach based on active chemical compounds, TRQC was found to regulate inflammation-related pathways, including NF-κB, NOD-like signaling, and MAPK signaling. In vitro experiments demonstrated that TRQC effectively suppressed LPS-induced activation of macrophages and the assembly of the NLRP3 inflammasome induced by LPS and Nigericin. These effects were attributed to the suppression of NF-κB and NOD-like signaling pathways. Furthermore, TRQC blocked MAPK signaling, thereby mitigating the inhibitory effects of LPS and Nigericin on Ca2+-dependent Cl- efflux across colonic epithelial cells. This mechanism generated a cathartic effect, potentially aiding in the removal of harmful substances and pathogenic bacteria.

CONCLUSION

Our study demonstrates that TRQC significantly mitigates ALI by effectively suppressing the NLRP3 inflammasome and MAPK/NF-κB signaling pathways. These findings suggest that TRQC could serve as a promising therapeutic candidate for inflammatory lung diseases, offering a novel approach to managing conditions like ALI and potentially extending to other inflammatory diseases.

Lipopolysaccharide-Neutralizing Peptide Modulates P2X7 Receptor-Mediated Interleukin-1β Release

Lipopolysaccharide (LPS)-neutralizing peptides are emerging as new potential therapeutic modalities to treat sepsis and skin infections. Purinergic ligand-gated ion channels (P2X receptors) play a critical role in various biological processes, including inflammation. Recent drug development efforts have significantly focused on the modulation of P2X receptors. Here, we investigated the effects of the synthetic LPS-neutralizing peptide Pep19-2.5 on human P2X receptors in cells of the innate immune system. Pep19-2.5 concentration-dependently triggered Ca2+ influx, interleukin (IL)-1β, and lactate dehydrogenase (LDH) release in Toll-like receptor-stimulated human macrophages and monocytes. Ca2+ influx was mediated at least partially by P2X7 receptors, and IL-1β and LDH release by P2X7 receptors, respectively. Confocal microscopy confirmed the colocalization of Pep19-2.5 with P2X7 receptors. Pep19-2.5-induced IL-1β release in primed cells was dependent on K+ efflux, caspase-1, and the nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3 inflammasome. In the presence of the P2X7 receptor agonist 2'(3')-O-(4-benzoylbenzoyl)adenosine-5'-triphosphate, Pep19-2.5 reduced IL-1β and LDH release. In 1321N1, astrocytoma cells stably transfected with human P2X receptors, Pep19-2.5 potently modulated P2X7 and P2X4 receptors (IC50 values of 0.346 and 0.146 μM, respectively) but showed less (P2X1, P2X3) or no activity (P2X2) at other P2X receptor subtypes. Our findings underline the potential of LPS-neutralizing peptides as modulators of P2X receptors, thus expanding their applicability beyond the treatment of sepsis to the treatment of inflammatory diseases.

Gut-liver axis in sepsis-associated liver injury: Epidemiology, challenges and clinical practice

Although the liver has a remarkable regenerative capacity, sepsis-associated liver injury (SLI) is a complication often seen in intensive care units. Due to its role in immune and inflammatory regulation, the liver is particularly vulnerable during severe infections. Understanding the global prevalence, causes, and management of SLI is essential to improve outcomes and reduce healthcare costs. This paper aims to explore these factors, with an emphasis on identifying effective strategies for clinical management. Zhang et al's bibliometric analysis of 787 publications (745 original articles and 42 reviews, mostly in animal models) from 2000 to 2023 highlights the growing interest in SLI, focusing on oxidative stress, gut microbiota, and inflammatory processes. Key components such as nuclear factor-kappa B and the NOD-like receptor thermal protein domain associated protein 3 inflammasome pathway, along with their links to gut microbiota imbalance and oxidative stress, are crucial for understanding SLI pathogenesis. The gut-liver axis, particularly the role of intestinal permeability and bacterial translocation in liver inflammation, is emphasized. In this context, bacterial translocation is especially relevant for critically ill patients, as it can exacerbate liver inflammation. The findings underscore the need for integrated care in intensive care units, prioritizing gut health and careful antibiotic use to prevent dysbiosis. Despite extensive research, there remains a lack of clinical trials to validate therapeutic approaches. The abundance of experimental studies highlights potential therapeutic targets, stressing the need for high-quality randomized clinical trials to translate these findings into clinical practice.

Immunometabolic Effect of Nitric Oxide on Human Macrophages Challenged With the SARS-CoV2-Induced Cytokine Storm. A Fluxomic Approach

The cytokine storm associated with SARS-CoV-2 infection is one of the most distinctive pathological signatures in COVID-19 patients. Macrophages respond to this pro-inflammatory challenge by reprogramming their functional and metabolic phenotypes. Interestingly, human macrophages fail to express the inducible form of the NO synthase (NOS2) in response to pro-inflammatory activation and, therefore, NO is not synthesized by these cells. The contribution of exogenously added NO, via a chemical NO-donor, on the immunometabolic changes associated with the cytokine storm is investigated. By using metabolic, transcriptomic, and functional assays the effect of NO in human macrophages is evaluated and found specific responses. Moreover, through integrative fluxomic analysis, pathways modified by NO that contribute to the expression of a particular phenotype in human macrophages are identified, which includes a decrease in mitochondrial respiration and TCA with a slight increase in the glycolytic flux. A significant ROS increase and preserved cell viability are observed in the presence of NO, which may ease the inflammatory response and host defense. Also, NO reverses the cytokine storm-induced itaconate accumulation. These changes offer additional clues to understanding the potential crosstalk between NO and the COVID-19 cytokine storm-dependent signaling pathways.

Berberine chloride loaded nano-PEGylated liposomes attenuates imidacloprid-induced neurotoxicity by inhibiting NLRP3/Caspase-1/GSDMD-mediated pyroptosis

Concerns have been expressed about imidacloprid (IMI), one of the most often used pesticides, and its potential neurotoxicity to non-target organisms. Chronic neuroinflammation is central to the pathology of several neurodegenerative disorders. Hence, exploring the molecular mechanism by which IMI would trigger neuroinflammation is particularly important. This study examined the neurotoxic effects of oral administration of IMI (45 mg/kg/day for 30 days) and the potential neuroprotective effect of berberine (Ber) chloride loaded nano-PEGylated liposomes (Ber-Lip) (10 mg/kg, intravenously every other day for 30 days) using laboratory rat. The histopathological changes, anti-oxidant and oxidative stress markers (GSH, SOD, and MDA), proinflammatory cytokines (IL1β and TNF-α), microglia phenotype markers (CD86 and iNOS for M1; CD163 for M2), the canonical pyroptotic pathway markers (NLRP3, caspase-1, GSDMD, and IL-18) and Alzheimer's disease markers (Neprilysin and beta amyloid [Aβ] deposits) were assessed. Oral administration of IMI resulted in apparent cerebellar histopathological alterations, oxidative stress, predominance of M1 microglia phenotype, significantly upregulated NLRP3, caspase-1, GSDMD, IL-18 and Aβ deposits and significantly decreased Neprilysin expression. Berberine reduced the IMI-induced aberrations in the measured parameters and improved the IMI-induced histopathological and ultrastructure alterations brought on by IMI. This study highlights the IMI neurotoxic effect and its potential contribution to the development of Alzheimer's disease and displayed the neuroprotective effect of Ber-Lip.

Baicalein inhibits NLRP3 inflammasome activation and mitigates placental inflammation and oxidative stress in gestational diabetes mellitus

Gestational diabetes mellitus (GDM) is a common metabolic disorder during pregnancy characterized by glucose intolerance, which poses risks to both maternal and fetal health. Baicalein, a flavonoid derived from the roots of Scutellaria baicalensis Georgi, exhibits various biological functions and has been implicated in the modulation of several diseases. However, the regulatory effects and underlying mechanisms of Baicalein in GDM progression remain unclear. In this study, we found that Baicalein ameliorates metabolic disturbances in GDM mice by improving glucose tolerance, insulin sensitivity, fasting blood glucose levels, and plasma insulin levels. Additionally, Baicalein treatment positively impacted litter size and birth weight. GDM mice exhibited increased inflammation and oxidative stress, which were mitigated following Baicalein administration (40 mg/kg). Furthermore, elevated protein levels of NLRP3, IL-1β, and IL-18 observed in GDM mice were reduced by Baicalein treatment. In conclusion, Baicalein inhibits the NLRP3 inflammasome and alleviates placental inflammation and oxidative stress associated with GDM. These findings provide valuable insights into the potential therapeutic role of Baicalein in managing GDM.

Mechanisms and Emerging Regulators of Neuroinflammation: Exploring New Therapeutic Strategies for Neurological Disorders

Neuroinflammation is a complex and dynamic response of the central nervous system (CNS) to injury, infection, and disease. While acute neuroinflammation plays a protective role by facilitating pathogen clearance and tissue repair, chronic and dysregulated inflammation contributes significantly to the progression of neurodegenerative disorders such as Alzheimer's disease, Parkinson's disease, and Multiple Sclerosis. This review explores the cellular and molecular mechanisms underlying neuroinflammation, focusing on the roles of microglia, astrocytes, and peripheral immune cells. Key signaling pathways, including NF-κB, JAK-STAT, and the NLRP3 inflammasome, are discussed alongside emerging regulators such as non-coding RNAs, epigenetic modifications, and the gut-brain axis. The therapeutic landscape is evolving, with traditional anti-inflammatory drugs like NSAIDs and corticosteroids offering limited efficacy in chronic conditions. Immunomodulators, gene and RNA-based therapeutics, and stem cell methods have all shown promise for more specific and effective interventions. Additionally, the modulation of metabolic states and gut microbiota has emerged as a novel strategy to regulate neuroinflammation. Despite significant progress, challenges remain in translating these findings into clinically viable therapies. Future studies should concentrate on integrated, interdisciplinary methods to reduce chronic neuroinflammation and slowing the progression of neurodegenerative disorders, providing opportunities for revolutionary advances in CNS therapies.