Innate immune activation through Nalp3 inflammasome sensing of asbestos and silica

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

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

Mitigation of nicotine-induced podocyte injury through inhibition of thioredoxin interacting protein

Nicotine has been reported to initiate NLRP3 inflammasome formation and activation in different pathological conditions. The current study assessed whether thioredoxin-interacting protein (TXNIP) mediates nicotine-induced NLRP3 inflammasome activation and consequent podocyte injury. Co-immunoprecipitation analysis demonstrated that nicotine-induced TXNIP/NLRP3 interaction in podocytes relative to control groups. However, pre-treatment with TXNIP inhibitors, verapamil (Vera) or SRI-37330 (SRI) attenuates nicotine-induced TXNIP/NLRP3 interaction. Confocal microscopic analysis showed that nicotine treatment significantly increased the colocalization of Nlrp3 with Asc, Nlrp3 with caspase-1 and Nlrp3 with TXNIP in podocytes compared to control cells. Pretreatment with TXNIP inhibitor Vera or SRI abolished nicotine-induced Nlrp3/Asc, Nlrp3/caspase-1 or Nlrp3/TXNIP colocalization. Correspondingly, nicotine treatment significantly increased the caspase-1 activity and IL-1β production compared to control cells. However, prior treatment with TXNIP inhibiting Vera or SRI significantly attenuated the nicotine-induced caspase-1 activity and IL-1β production. Further immunofluorescence analysis showed that nicotine treatment significantly decreased podocin and nephrin expression compared to control cells. However, pretreatment with TXNIP inhibiting Vera or SRI attenuated the nicotine-induced podocin and nephrin reduction. In addition, confocal, flow cytometry and biochemical analysis showed that nicotine treatment significantly increased desmin expression, apoptosis and cell permeability compared to control cells. However, prior treatment with TXNIP inhibiting Vera or SRI significantly attenuated the nicotine-induced desmin expression, apoptosis and cell permeability. Taken together, our results demonstrate that TXNIP/NLRP3 interaction constitutes a potentially key signalling mechanism driving nicotine-induced NLRP3 inflammasome formation, activation and subsequent podocyte damage.

Microglial NOX2 as a therapeutic target in traumatic brain injury: Mechanisms, consequences, and potential for neuroprotection

Traumatic brain injury (TBI) is a leading cause of long-term disability worldwide, with secondary injury mechanisms, including neuroinflammation and oxidative stress, driving much of its chronic pathology. While NADPH oxidase 2 (NOX2)-mediated reactive oxygen species (ROS) production is a recognized factor in TBI, the specific role of microglial NOX2 in perpetuating oxidative and inflammatory damage remains underexplored. Addressing this gap is critical, as current therapeutic approaches primarily target acute symptoms and fail to interrupt the persistent neuroinflammation that contributes to progressive neurodegeneration. Besides NOX, other ROS-generating enzymes, such as CYP1B1, COX2, and XO, also play crucial roles in triggering oxidative stress and neuroinflammatory conditions in TBI. However, this review highlights the pathophysiological role of microglial NOX2 in TBI, focusing on its activation following injury and its impact on ROS generation, neuroinflammatory signaling, and neuronal loss. These insights reveal NOX2 as a critical driver of secondary injury, linked to worsened outcomes, particularly in aged individuals where NOX2 activation is more pronounced. In addition, this review evaluates emerging therapeutic approaches targeting NOX2, such as GSK2795039 and other selective NOX2 inhibitors, which show potential in reducing ROS levels, limiting neuroinflammation, and preserving neurological functions. By highlighting the specific role of NOX2 in microglial ROS production and secondary neurodegeneration, this study advocates for NOX2 inhibition as a promising strategy to improve TBI outcomes by addressing the unmet need for therapies targeting long-term inflammation and neuroprotection. Our review highlights the potential of NOX2-targeted interventions to disrupt the cycle of oxidative stress and inflammation, ultimately offering a pathway to mitigate the chronic impact of TBI.

Clustering of NLRP3 induced by membrane or protein scaffolds promotes inflammasome assembly

NLRP3 is a pattern recognition receptor forming an inflammasome in response to diverse pathogen and self-derived triggers, but molecular insights on NLRP3 activation are still lacking. Here, we drive ectopic NLRP3 to different subcellular locations in NLRP3-deficient macrophages to map the spatial activation profile of NLRP3, and find that NLRP3 variants enriched at the organellar membranes respond to canonical triggers similarly to wild-type NLRP3; however, unlike wild-type, these NLRP3 variants can be activated even in the absence of the polybasic phospholipid-binding segment. Mechanistically, membrane or protein scaffolds mediate NLRP3 clustering, which leads to the unfastening of the inactive NACHT domain conformation preceding the activated NLRP3 oligomer formation. Our data thus suggest that scaffold-promoted clustering is an important step in NLRP3 activation, enabling NLRP3 to sense distinct activator-induced cellular anomalies exhibited via lipid or protein assemblies, thereby establishing NLRP3 as the master sensor of perturbations in cell homeostasis.

TMEM175 activity in BK-deficient macrophages maintains lysosomal function and mediates silica-induced inflammatory response in macrophages

Objective: Lysosomal ion channel function in macrophages contributes to the development of silica-induced inflammation. Recent studies have shown that blocking K+ entry into the lysosome via the BK channel reduces silica-induced damage and inflammation in macrophages. This study aims to explore the mechanisms of particle-induced inflammation in BK-/- macrophages. Methods: Bone marrow derived macrophages (BMdM) from C57BL/6 wildtype (WT) and BK-/- mice were exposed in vitro to silica and IL-1β release and cell death assessed. The effect of BK-/- on lysosomal pH, proteolytic activity, and cholesterol accumulation was evaluated. Results: BK-/- BMdM failed to demonstrate a reduction in IL-1β or cell death following silica exposure. BK-/- BMdM had comparable lysosome function to WT suggesting a compensatory mechanism was maintaining lysosome function. BK-/- macrophages demonstrated an upregulation of a second lysosomal potassium channel, TMEM175. Inhibition of TMEM175 activity caused an increase in lysosomal pH and reduced silica-induced cell death and IL-1β release in both BK-/- and WT BMdM. Conclusion: BK-/- BMdM did not exhibit the same phenotype seen with pharmaceutical abrogation of BK channel activity and showed no differences from WT in response to silica exposure. Upregulation of TMEM175 in BK-/- macrophages appears to prevent changes in lysosomal pH and cholesterol accumulation. Inhibiting TMEM175 activity in both BK-/- and WT BMdM resulted in an increase in lysosomal pH and reduced silica-induced inflammation, suggesting that reduced particle-induced cell damage and inflammation is not dependent on the activity of a single lysosomal ion channel but rather on mechanisms that elevate lysosomal pH.

Mitigating microplastic-induced organ Damage: Mechanistic insights from the microplastic-macrophage axes

We live in a world increasingly dominated by plastic, leading to the generation of microplastic particles that pose significant global health concerns. Microplastics can enter the body via ingestion, inhalation, and direct contact, accumulating in various tissues and potentially causing harm. Despite this, the specific cellular mechanisms and signaling pathways involved remain poorly understood. Macrophages are essential in absorbing, distributing, and eliminating microplastics, playing a key role in the body's defense mechanisms. Recent evidence highlights oxidative stress signaling as a key pathway in microplastic-induced macrophage dysfunction. The accumulation of microplastics generates reactive oxygen species (ROS), disrupting normal macrophage functions and exacerbating inflammation and organ damage. This review serves as the first comprehensive examination of the interplay between microplastics, macrophages, and oxidative stress. It discusses how oxidative stress mediates macrophage responses to microplastics and explores the interactions with gut microbiota. Additionally, it reviews the organ damage resulting from alterations in macrophage function mediated by microplastics and offers a novel perspective on the defense, assessment, and treatment of microplastic-induced harm from the viewpoint of macrophages.

Targeting oxidative stress-mediated regulated cell death as a vulnerability in cancer

Reactive oxygen species (ROS), regulators of cellular behaviors ranging from signaling to cell death, have complex production and control mechanisms to maintain a dynamic redox balance under physiological conditions. Redox imbalance is frequently observed in tumor cells, where ROS within tolerable limits promote oncogenic transformation, while excessive ROS induce a range of regulated cell death (RCD). As such, targeting ROS-mediated regulated cell death as a vulnerability in cancer. However, the precise regulatory networks governing ROS-mediated cancer cell death and their therapeutic applications remain inadequately characterized. In this Review, we first provide a comprehensive overview of the mechanisms underlying ROS production and control within cells, highlighting their dynamic balance. Next, we discuss the paradoxical nature of the redox system in tumor cells, where ROS can promote tumor growth or suppress it, depending on the context. We also systematically explored the role of ROS in tumor signaling pathways and revealed the complex ROS-mediated cross-linking networks in cancer cells. Following this, we focus on the intricate regulation of ROS in RCD and its current applications in cancer therapy. We further summarize the potential of ROS-induced RCD-based therapies, particularly those mediated by drugs targeting specific redox balance mechanisms. Finally, we address the measurement of ROS and oxidative damage in research, discussing existing challenges and future prospects of targeting ROS-mediated RCD in cancer therapy. We hope this review will offer promise for the clinical application of targeting oxidative stress-mediated regulated cell death in cancer therapy.

Cellular defense mechanisms against asbestos fibers

Although inhalation of sufficient doses and dimensions of airborne asbestos dusts in an occupational setting can produce cancer in the lungs, pleura and peritoneum, tumors occur in <5-10% of exposed individuals, even among persons with considerable historical exposures. In this perspective, we review cell defense mechanisms that are involved in protective and adaptive responses to asbestos exposure. These adaptive responses are orchestrated through a multifaceted cellular program involving the concerted action of diverse stress response pathways, including antioxidant responses, DNA repair mechanisms, molecular mechanisms for intracellular signaling leading to proliferation, apoptosis, and inflammation, and cell cycle regulation. These cell defenses suggest that humans can adjust to moderate levels of stress or change without experiencing negative effects, implying the existence of a threshold dose. Likewise, reported no-observed adverse-effect levels (NOAELs) for various asbestos fiber types and asbestos-related cancers in experimental and epidemiological data further support the existence of a threshold dose and are discussed here.

SiO2 particles induce pulmonary fibrosis by modulating NLRP3 through the ROS/Keap1/Nrf2 signaling pathway in rats

Recent studies have shown that the activation of the ROS-dependent NLRP3 inflammasome plays a key role in the pathogenesis of silicosis; however, the mechanism by which SiO2-induced ROS activates NLRP3 remains unclear. In this study, rats were intratracheally instilled with a SiO2 suspension once and then received daily intravenous injections of NAC (at doses of 20, 40, and 80 mg/kg, respectively) to inhibit SiO2-induced ROS. Rats that were intratracheally instilled with a SiO2 suspension once served as silicosis models, while those that were intratracheally instilled with PBS once served as controls. After 40 days, lung samples were taken for pathological observation, and the BALF was collected to measure ROS levels. The mRNA and protein expression levels of Keap1/Nrf2 signaling indicators (Keap1, Nrf2) and NLRP3 inflammasome indicators (NLRP3, GSDMD) were detected. The results showed that the Keap1/Nrf2 signaling pathway and the NLRP3 were activated in the silicosis rat lungs, accompanied by an increase in ROS levels. When ROS was inhibited, the Keap1/Nrf2 signaling pathway, the NLRP3, and the degree of pulmonary fibrosis were all suppressed in a dose-dependent manner. Therefore, we conclude that SiO2 particles induce pulmonary fibrosis in rats by modulating the NLRP3 inflammasome via the ROS/Keap1/Nrf2 signaling pathway.

Stimulation of macrophage cell lines confined with silica and/or silicon particles and embedded in structured collagen gels

Macrophages encapsulated in composite gels are subjected to a three-dimensional (3D) microenvironment and material-related stimuli that allow modulation of their phenotypes. Herein, 3D collagen fibrillar networks structured with di- or tri-functionalized oligourethanes, including Si-O or Si-Si particles confined therein, are compared regarding their physicochemical properties and material-guided macrophage activation. Gelation kinetics, degradation/swelling, and rheometric results demonstrated that the properties of the composite gels depend on the oligourethane functionalization number (derived from diols/triols and L-Lysine diisocyanate, LDI) and silica incorporation. Human or murine macrophages seeded or encapsulated in the composite gels showed good viability and the adoption of an anti-inflammatory phenotype in response to the silica in the composite gel, showing accelerated gelation when cell culture components are present in the liquid precursors. An increase in cell viability proportional to the storage modulus was observed. ELISA tests strongly suggest that the Si-Si nanoparticles in the composites can antagonize the pro-inflammatory stimulation with lipopolysaccharides (LPS) and interferon-gamma (IFNγ), even promoting an anti-inflammatory response in embedded cells after 24 h. Silicon-doped and crosslinked collagen gels have good potential to modulate macrophage inflammatory response, serving as a 3D immunomodulatory scaffold.

Siglec-14-Mediated Inflammatory Responses to Carbon Nanomaterials

Carbon nanomaterials (CNM), including carbon nanotubes (CNT) and graphene nanoplatelets (GNP), are expected to have diverse industrial applications due to their unique physical properties. However, concerns have been raised regarding their toxicity in humans. In this context, risk assessment must include an understanding of the molecular mechanisms underlying human recognition of CNM. We have recently identified human sialic acid-binding immunoglobulin-like lectin (Siglec)-14 as a CNT-recognizing receptor. Since no rodent orthologs for Siglec-14 exist, previous rodent toxicological studies may underestimate CNM toxicity in humans. Therefore, in this study, we investigate Siglec-14 responses to various CNM. Siglec-14 recognizes various types of CNM via its extracellular aromatic cluster with a similar affinity, regardless of size and shape. Ultrathin single-walled CNT (SWCNT) and spherical carbon black nanoparticles (CBNP) activated macrophage Siglec-14 signaling, leading to IL-8 production. Notably, GNP as well as long needle-like MWCNT not only activate this inflammatory signal but also cause phagosomal damage, leading to the release of IL-1β, the most prominent pro-inflammatory cytokine. In mice transduced with Siglec-14, intratracheal injection of GNP or long needle-like MWCNT caused lung inflammation, whereas injection of SWCNT or CBNP did not. Taken together, these results suggest that CNM-induced inflammation requires two processes: macrophage receptor ligation and phagosomal damage. This indicates that CNM may be safe unless they cause damage to the macrophage phagosome.

NLRP3 inflammasome-mediated premature immunosenescence drives diabetic vascular aging dependent on the induction of perivascular adipose tissue dysfunction

AIMS

The vascular aging process accelerated by type 2 diabetes mellitus (T2DM) is responsible for the elevated risk of associated cardiovascular diseases. Metabolic disorder-induced immune senescence has been implicated in multi-organ/tissue damage. Herein, we sought to determine the role of immunosenescence in diabetic vascular aging and to investigate the underlying mechanisms.

METHODS AND RESULTS

Aging hallmarks of the immune system appear prior to the vasculature in streptozotocin (STZ)/high-fat diet (HFD)-induced T2DM mice or db/db mice. Transplantation of aged splenocytes or diabetic splenocytes into young mice triggered vascular senescence and injury compared with normal control splenocyte transfer. RNA sequencing profile and validation in immune tissues revealed that the toll-like receptor 4-nuclear factor-kappa B-NLRP3 axis might be the mediator of diabetic premature immunosenescence. The absence of Nlrp3 attenuated immune senescence and vascular aging during T2DM. Importantly, senescent immune cells, particularly T cells, provoked perivascular adipose tissue (PVAT) dysfunction and alternations in its secretome, which in turn impair vascular biology. In addition, senescent immune cells may uniquely affect vasoconstriction via influencing PVAT. Lastly, rapamycin alleviated diabetic immune senescence and vascular aging, which may be partly due to NLRP3 signalling inhibition.

CONCLUSION

These results indicated that NLRP3 inflammasome-mediated immunosenescence precedes and drives diabetic vascular aging. The contribution of senescent immune cells to vascular aging is a combined effect of their direct effects and induction of PVAT dysfunction, the latter of which can uniquely affect vasoconstriction. We further demonstrated that infiltration of senescent T cells in PVAT was increased and associated with PVAT secretome alterations. Our findings suggest that blocking the NLRP3 pathway may prevent early immunosenescence and thus mitigate diabetic vascular aging and damage, and targeting senescent T cells or PVAT might also be the potential therapeutic approach.

A complex of NLRP3 with caspase-4 is essential for inflammasome activation by Tannerella forsythia infection

Periodontitis, a chronic inflammatory disease of periodontal tissue, is often associated with a group of pathogenic bacteria known as the "red complex", including Tannerella forsythia. Previous papers showed that T. forsythia induces many kinds of inflammatory cytokines including interleukin (IL)-1β regulated by inflammasome activation. However, the physiological function of periodontitis and the mechanism to induce inflammasome activation by T. forsythia infection are poorly understood. In this study, we demonstrate that the Nod-like receptor pyrin domain containing 3 (NLRP3) and caspase-4 are essential for inflammasome activation by T. forsythia infection, playing a crucial role in IL-1β maturation in THP-1 cells. We also showed that the knockout of ASC or Gasdermin D suppresses pyroptotic cell death. Moreover, co-immunoprecipitation assays confirmed the formation of a complex involving caspase-4, NLRP3, and ASC following T. forsythia infection. Additionally, reactive oxygen species production was identified as a key factor in caspase-4-mediated NLRP3 inflammasome activation by T. forsythia infection. These results enhance our understanding of inflammasome activation in response to T. forsythia infection and provide new insights into the pathogenic mechanisms of periodontitis.

Proteomics and Metabolomics Analyses Reveal a Dynamic Landscape of Coal Workers' Pneumoconiosis: An Insight into Disease Progression

Coal worker's pneumoconiosis (CWP) is characterized by chronic inflammation and pulmonary fibrosis. The key factor contributing to the incurability of CWP is the unclear pathogenesis. This study explored the characteristic changes in proteomics and metabolomics of early and advanced CWP patients through proteomics and metabolomics techniques. Proteomics identified proteins that change with the progression of CWP, with significant enrichment in the TGF-β signaling pathway and autoimmune disease pathways. Metabolomics revealed the metabolic characteristics of CWP at different stages. These metabolites mainly include changes in amino acid metabolism, unsaturated fatty acid synthesis, and related metabolites. Integrated analysis found that ABC transporters are a shared pathway among the three groups, and ABCD2 is involved in the ABC transporter pathway. In the subsequent independent sample verification analysis, consistent with proteomics experiments, compared to the CM group, FMOD expression level was upregulated in the NIC group. TFR expression level was consistently downregulated in both the IC and NIC groups. Additionally, ABCD2 increased in the IC group but decreased in the NIC group. In summary, this study revealed the metabolic characteristics of CWP at different stages. These findings may provide valuable insights for the early prediction, diagnosis, and treatment of CWP.

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.

Ozone-induced lung injury and inflammation: Pathways and therapeutic targets for pulmonary diseases caused by air pollutants

Exposure to ambient Ozone (O3) air pollution directly causes by its oxidative properties, respiratory epithelial cell injury, and cell death, which promote inflammation and hyperreactivity, posing a significant public health concern. Recent clinical and experimental studies have made strides in elucidating the mechanisms underlying O3-induced epithelial cell injury, inflammation, and airway hyperreactivity, which are discussed herein. The current data suggest that O3-induced oxidative stress is a central event-inducing oxeiptotic cell death pathway. O3-induced epithelial barrier damage and cell death, triggering the release of alarmins and damage-associated molecular patterns (DAMPs), with subsequent endogenous activation of Toll-like receptors (TLRs), DNA sensing pathways, and inflammasomes, activating interleukin-1-Myd88 inflammatory pathway with the production of a range of chemokines and cytokines. This cascade orchestrates lung tissue-resident cell activation in response to O3 in leukocyte and non-leukocyte populations, driving sterile innate immune response. Chronic inflammatory response to O3, by repeated exposures, supports a mixed phenotype combining asthma and emphysema, in which their exacerbation by other particulate pollutants potentially culminates in respiratory failure. We use data from lung single-cell transcriptomics to map genes of O3-damage sensing and signaling pathways to lung cells and thereby highlight potential hotspots of O3 responses. Deeper insights into these pathological pathways might be helpful for the identification of novel therapeutic targets and strategies.

Idiopathic Pulmonary Fibrosis Caused by Damaged Mitochondria and Imbalanced Protein Homeostasis in Alveolar Epithelial Type II Cell

Alveolar epithelial Type II (ATII) cells are closely associated with early events of Idiopathic pulmonary fibrosis (IPF). Proteostasis dysfunction, endoplasmic reticulum (ER) stress, and mitochondrial dysfunction are known causes of decreased proliferation of alveolar epithelial cells and the secretion of pro-fibrotic mediators. Here, a large body of evidence is systematized and a cascade relationship between protein homeostasis, endoplasmic reticulum stress, mitochondrial dysfunction, and fibrotropic cytokines is proposed, providing a theoretical basis for ATII cells dysfunction as a possible pathophysiological initiating event for idiopathic pulmonary fibrosis.

Exploring NLRP3-related phenotypic fingerprints in human macrophages using Cell Painting assay

Existing research has proven difficult to understand the interplay between upstream signaling events during NLRP3 inflammasome activation. Additionally, events downstream of inflammasome complex formation such as cytokine release and pyroptosis can exhibit variation, further complicating matters. Cell Painting has emerged as a prominent tool for unbiased evaluation of the effect of perturbations on cell morphological phenotypes. Using this technique, phenotypic fingerprints can be generated that reveal connections between phenotypes and possible modes of action. To the best of our knowledge, this was the first study that utilized Cell Painting on human THP-1 macrophages to generate phenotypic fingerprints in response to different endogenous and exogenous NLRP3 inflammasome triggers and to identify phenotypic features specific to NLRP3 inflammasome complex formation. Our results demonstrated that not only can Cell Painting generate morphological fingerprints that are NLRP3 trigger-specific but it can also identify cellular fingerprints associated with NLRP3 inflammasome activation.

Allergy Treatment: A Comprehensive Review of Nanoparticle-based Allergen Immunotherapy

Allergic disorders rising in prevalence globally, affecting a substantial proportion of individuals in industrialized nations. The imbalance in the immune system, characterized by elevated allergen-specific T helper 2 (Th2) cells and immunoglobulin E (IgE) antibodies, is a key factor in allergy development. Allergen-specific immunotherapy (AIT) is the only treatment capable of alleviating allergic symptoms, preventing new sensitizations, and reducing asthma risk in allergic rhinitis patients. Traditional AIT, however, faces challenges such as frequent administration, adverse effects, and inconsistent patient outcomes. Nanoparticle-based approaches have emerged as a promising strategy to enhance AIT. This review explores the utilization of nanoparticles in AIT, highlighting their ability to interact with the immune system and improve therapeutic outcomes. Various types of nanoparticles, including polyesters, polysaccharide polymers, liposomes, protamine-based nanoparticles (NPs), and polyanhydrides, have been employed as adjuvants or carriers to enhance AIT's efficacy and safety. Nanoparticles offer advantages such as allergen protection, improved immune response modulation, targeted cell delivery, and reduced side effects. This review provides an overview of the current landscape of nanoparticle-based allergen immunotherapy, discussing its potential to revolutionize allergy treatment compared to traditional immunotherapy.

Functional Characterization of the Hephaestin Variant D568H Provides Novel Mechanistic Insights on Iron-Dependent Asbestos-Induced Carcinogenesis

A local disruption of iron homeostasis leading to oxidative stress is considered one of the main mechanisms of asbestos-related genotoxicity. Another aspect contributing to the risk of developing pathological consequences upon asbestos exposure is individual genetic factors. In a previous study, we identified a coding SNP in the hephaestin gene (HEPH) that protects against developing asbestos-related thoracic cancer. Heph is a ferroxidase that promotes iron export in concert with the permease ferroportin (Fpn1). Here, we performed an in-depth functional characterization of the HephD568H variant to gain insights into the molecular basis of its protective activity. We showed that HephD568H forms a complex with Fpn1 and possesses full ferroxidase activity. Although HephD568H is more efficiently recruited to the plasma membrane, it is impaired in binding iron-deficient Tfn, whose interaction with wild-type (WT) ferroxidase emerged as a novel mechanism to perceive brain iron needs. Heph is expressed in the human lung by pericytes and fibroblasts, and lung pericytes were shown to respond to iron demand by upregulating the iron exporter pair. These results extend the paradigm of local iron regulation discovered at the blood-brain barrier to the pulmonary vasculature. Furthermore, they establish a mechanistic link between changes in iron sensing and the risk of developing asbestos-related malignancies.

Silica-induced ferroptosis activates retinoic acid signaling in dendritic cells to drive inflammation and fibrosis in silicosis

Silicosis, a chronic lung disease caused by inhalation of silica (SiO2) particles from environmental contamination or industrial exposure, is characterized by persistent inflammation and fibrosis. This study elucidates a novel mechanism where SiO2 exposure triggers ferroptosis, a lipid peroxidation-dependent form of cell death, in dendritic cells (DCs), thereby activating retinoic acid (RA) signaling. The RA response amplifies inflammatory pathways, including cGAS-STING-IFN-I and IL-1β signaling, exacerbating lung inflammation and fibrosis. The study uses murine models to demonstrate that ferroptosis inhibitors, such as ferrostatin-1, mitigate SiO2-induced inflammation and collagen deposition. Furthermore, systemic administration of the synthetic retinoid AM80 reduces pulmonary damage by modulating immune cell distribution and promoting lymphocyte homing. These findings reveal the interplay between ferroptosis and RA signaling as a pivotal driver of silicosis pathology and suggest therapeutic avenues targeting ferroptosis and RA modulation for disease management.

Interaction, diagnosis, and treatment of lung microbiota-NLRP3 inflammasome-target organ axis in sepsis

Sepsis is defined as a life-threatening condition caused by a dysregulated host response to infection, leading to multi-organ dysfunction, and representing a significant global health burden. The progression of sepsis is closely linked to disruptions in lung microbiota, including bacterial translocation, impaired barrier function, and local microenvironmental disturbances. Conversely, the worsening of sepsis exacerbates lung microbiota imbalances, contributing to multi-organ dysfunction. Recent culture-independent microbiological techniques have unveiled the complexity of the respiratory tract microbiome, necessitating a reassessment of the interactions between the host, microbes, and pathogenesis in sepsis. This review synthesizes current insights into the causes of microbiota dysbiosis and the regulatory mechanisms of the NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome, as well as their interactions during sepsis and sepsis-induced organ dysfunction. In addition, we summarize novel diagnostic and therapeutic approaches from the current study that may offer promising prospects for the management of sepsis.

Porcine β-defensin 5 (pBD-5) modulates the inflammatory and metabolic host intestinal response to infection

Swine dysentery (SD) presents considerable challenges to both animal welfare and pork industry sustainability. Control and prevention of SD rely on antibiotics and non-vaccine biosecurity practices. Host defense peptides (HDPs) have emerged as promising alternatives to treat and prevent such health concern. This study investigated the effects of porcine β-defensin 5 (pBD-5) and its potential host cytotoxicity, metabolic influence, gene expression modulation and direct antimicrobial activity on Brachyspira hyodysenteriae growth in vitro. pBD-5 does not directly inhibit B. hyodysenteriae growth or significantly alters the metabolic activity or membrane integrity of host cells, indicating no significant cytotoxicity at the tested concentrations. Host transcriptome sequencing revealed a reduction in the number of differentially expressed genes in cells exposed to B. hyodysenteriae following pBD-5 treatment, when compared to the pathogen alone, suggesting an immunomodulatory effect. Pathway analysis revealed the downregulation of immune-related pathways, including IL-17, toll-like receptor (TLR), and NOD-like receptor signalling pathways, upon pBD-5 exposure. Conversely, metabolic pathways such as ribosome, protein digestion and absorption, and renin-angiotensin system were upregulated by pBD-5 treatment, hinting at a role in producing and conserving energy during the challenge. While this study offers insights into the immunomodulatory effects of pBD-5, further research is necessary to elucidate its precise mechanisms and potential applications as an alternative treatment for infectious diseases.

Dihydromyricetin Suppresses Lipopolysaccharide-Induced Intestinal Injury Through Reducing Reactive Oxygen Species Generation and NOD-Like Receptor Pyrin Domain Containing 3 Inflammasome Activation

As an integral component of the gram-negative bacterial cellular envelope, excess production of lipopolysaccharide (LPS) regularly precipitates causing intestinal damage and barrier dysfunction in avian species. Dihydromyricetin (DHM), a naturally occurring constituent in rattan tea, exhibits protective characteristics against various tissue injuries. However, the intervention mechanism of DHM on intestinal injury induced by LPS in chickens has not been determined. Consequently, this study aimed to elucidate the mechanisms through which DHM mitigates LPS-induced intestinal damage in chickens through the reactive oxygen species (ROS)-NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome. Primary intestinal epithelial cells (IECs) were isolated and cultured from 14-day-old specific pathogen free (SPF) chicken embryos, and DHM ranging from 20 to 320 μmol/L increased cell survival rates. Additionally, DHM at 20 and 40 μmol/L demonstrated reduction in oxidative stress and ROS accumulation, mirroring the impact of ROS inhibitor (2.5 mmol/L NAC). DHM efficiently regulated ROS production, thereby augmenting ZO-1, occludin and claudin-1 expression to enhance barrier function; upregulating bcl-2 expression and downregulating bax and caspase-3 expression to regulate apoptosis and suppressing inflammation in IECs. Suppression of ROS subsequently attenuates NLRP3 inflammasome activation, leading to a remarkable downregulation of IL-1β, IL-18 and lactate dehydrogenase (LDH) secretion, consistent with direct inactivation of NLRP3 inflammasome (10 μmol/L MCC950). Notably, DHM diminished IL-1β and IL-18 levels and LDH activity via suppression of ROS-regulated NLRP3 and caspase-1 expression and activation. In summary, DHM prevents LPS-induced intestinal impairment by modulating ROS generation and NLRP3 inflammasome activation.

The spectrum of lysosomal stress and damage responses: from mechanosensing to inflammation

Cells and tissues turn over their aged and damaged components in order to adapt to a changing environment and maintain homeostasis. These functions rely on lysosomes, dynamic and heterogeneous organelles that play essential roles in nutrient redistribution, metabolism, signaling, gene regulation, plasma membrane repair, and immunity. Because of metabolic fluctuations and pathogenic threats, lysosomes must adapt in the short and long term to maintain functionality. In response to such challenges, lysosomes deploy a variety of mechanisms that prevent the breaching of their membrane and escape of their contents, including pathogen-associated molecules and hydrolases. While transient permeabilization of the lysosomal membrane can have acute beneficial effects, supporting inflammation and antigen cross-presentation, sustained or repeated lysosomal perforations have adverse metabolic and transcriptional consequences and can lead to cell death. This review outlines factors contributing to lysosomal stress and damage perception, as well as remedial processes aimed at addressing lysosomal disruptions. We conclude that lysosomal stress plays widespread roles in human physiology and pathology, the understanding and manipulation of which can open the door to novel therapeutic strategies.

Pro-inflammatory macrophages produce mitochondria-derived superoxide by reverse electron transport at complex I that regulates IL-1β release during NLRP3 inflammasome activation

Macrophages stimulated by lipopolysaccharide (LPS) generate mitochondria-derived reactive oxygen species (mtROS) that act as antimicrobial agents and redox signals; however, the mechanism of LPS-induced mitochondrial superoxide generation is unknown. Here we show that LPS-stimulated bone-marrow-derived macrophages produce superoxide by reverse electron transport (RET) at complex I of the electron transport chain. Using chemical biology and genetic approaches, we demonstrate that superoxide production is driven by LPS-induced metabolic reprogramming, which increases the proton motive force (∆p), primarily as elevated mitochondrial membrane potential (Δψm) and maintains a reduced CoQ pool. The key metabolic changes are repurposing of ATP production from oxidative phosphorylation to glycolysis, which reduces reliance on F1FO-ATP synthase activity resulting in a higher ∆p, while oxidation of succinate sustains a reduced CoQ pool. Furthermore, the production of mtROS by RET regulates IL-1β release during NLRP3 inflammasome activation. Thus, we demonstrate that ROS generated by RET is an important mitochondria-derived signal that regulates macrophage cytokine production.

Occupational dust and chemical exposures and the development of autoimmune rheumatic diseases

Although the association between certain occupational exposures and the development of autoimmune rheumatic disease was first described over a century ago, this association has only become more widely recognized in the past 10 years because of the use of high-silica-content engineered stone in construction and home renovation. There is now a substantial and growing body of evidence that occupational dust and chemical exposure, be it through mining, stonemasonry, building or other trades, increases the risk of various systemic autoimmune rheumatic diseases (SARDs) including rheumatoid arthritis and systemic sclerosis. Although the pathogenic mechanisms of silica-induced autoimmunity are not fully elucidated, it is thought that alveolar macrophage ingestion of silica and the ensuing phagosomal damage is an initiating event that ultimately leads to production of autoantibodies and immune-mediated tissue injury. The purportedly causal association between occupational exposure to chemicals, such as organic solvents, and an increased risk of SARDs is less frequently recognized compared with silica dust, and its immunopathogenesis is less well understood. An appreciation of the importance of occupational dust and chemical exposures in the development of SARDs has implications for workplace health and safety regulations and offers a unique opportunity to better understand autoimmune disease pathogenesis and implement preventative strategies.

Preclinical studies of natural flavonoids in inflammatory bowel disease based on macrophages: a systematic review with meta-analysis and network pharmacology

Flavonoid is a category of bioactive polyphenolic compounds that are extensively distributed in plants with specific pharmacological properties, such as anti-inflammatory and anti-oxidant. Importantly, natural flavonoids have shown the protected function on the dextran sulfate sodium (DSS)-induced colitis in animals and lipopolysaccharides (LPS)-induced inflammatory response in macrophages. The purpose of this systematic review is to explore the efficacy of natural flavonoids in animal models of IBD (inflammatory bowel disease) and potential mechanisms in macrophages by meta-analysis and network pharmacology in preclinical studies. Relevant foundation studies were searched from January 2010 to November 2023 in databases like PubMed, Elsevier ScienceDirect, and Web of Science. Then, OriginPro software was used to extract values from images, and the analysis was performed using Review Manager 5.3. The retrieved data was analyzed according to the fixed-effects model and random-effects model. Subsequently, heterogeneity was evaluated using the I2 statistics. Lastly, network pharmacology was applied to confirm mechanisms of natural flavonoids on IBD. According to the results of meta-analysis, we found the natural flavonoids exhibited powerful therapeutic effects against IBD, which not only reversed colonic shortness (WMD = 1.33, 95% CI (1.07, 1.59), P < 0.00001), but also reduced histological score (SMD =  - 2.66, 95% CI (- 3.77, - 1.95), P < 0.00001) between natural flavonoid treatment groups compared with the experimental IBD model. Furthermore, treatment with natural flavonoids decreased the levels of tumor necrosis factor-α (TNF-α) in macrophages. Mechanistically, our summarized data substantiate that natural flavonoids alleviate LPS-induced M1 macrophage polarization, anti-oxidant, anti-inflammatory, maintain intestinal barrier, and inhibit the activation of the NLR family pyrin domain containing 3 (NLRP3) inflammasome in macrophages. Moreover, the results of network pharmacology also support this. This systematic review demonstrated the efficiency of natural flavonoids in treating IBD in preclinical research by meta-analysis and network pharmacology, which offered supporting evidence for clinical trial implementation. However, some limitations remain present, such as technique quality shortage, missed reports on account of negative results, failure to count sample size, and the risk of bias.

The impact of biocorrosion and titanium ions release on peri-implantitis

OBJECTIVES

Biofilm accumulation is considered the primary cause of peri-implant inflammation. Still, metallosis caused by an increased concentration of titanium ions at the site of peri-implantitis site cannot be ignored. Whether titanium ions alone or in concert with bacterial biofilm trigger inflammation and bone destruction in peri-implant tissues remains unproven.

MATERIALS AND METHODS

Articles were retrieved from PubMed/Medline, Web of Science. All studies focusing on titanium ions release in peri-implant reactions were included and evaluated.

RESULTS

Titanium implants are considered non-inert and may release titanium ions in the intraoral microenvironment, the most important of which is the acidic environment created by bacterial biofilms. Although the correlation between titanium ion release and the incidence or progression of peri-implantitis is controversial, several studies have confirmed the potential role of titanium ions. Diffusion or entry of titanium ions into the circulation may be a scavenging effect on local titanium ions but can cause systemic adverse effects. However, existing measures are not yet able to balance reducing biocorrosion and maintaining osteogenic results, and the exploration of new materials requires long-term clinical data.

CONCLUSIONS

Titanium ions have potential impacts on peri-implant tissue and systemic circulation. Titanium ions are closely associated with bacterial biofilms in the occurrence and development of periimplantitis. The preventive strategies for the release and action of titanium ions remain to be explored.

CLINICAL RELEVANCE

Our findings may provide the hope of shedding light on the pathogenesis of peri-implantitis and its treatment.

Acid Sphingomyelinase and Ceramide Signaling Pathway Mediates Nicotine-Induced NLRP3 Inflammasome Activation and Podocyte Injury

Background: Recent studies have shown that Nlrp3 inflammasome activation is importantly involved in podocyte dysfunction induced by nicotine. The present study was designed to test whether acid sphingomyelinase (Asm) and ceramide signaling play a role in mediating nicotine-induced Nlrp3 inflammasome activation and subsequent podocyte damage. Methods and Results: Nicotine treatment significantly increased the Asm expression and ceramide production compared to control cells. However, prior treatment with amitriptyline, an Asm inhibitor significantly attenuated the nicotine-induced Asm expression and ceramide production. Confocal microscopic and biochemical analyses showed that nicotine treatment increased the colocalization of NLRP3 with Asc, Nlrp3 vs. caspase-1, IL-1β production, caspase-1 activity, and desmin expression in podocytes compared to control cells. Pretreatment with amitriptyline abolished the nicotine-induced colocalization of NLRP3 with Asc, Nlrp3 with caspase-1, IL-1β production, caspase-1 activity and desmin expression. Immunofluorescence analyses showed that nicotine treatment significantly decreased the podocin expression compared to control cells. However, prior treatment with amitriptyline attenuated the nicotine-induced podocin reduction. In addition, nicotine treatment significantly increased the cell permeability, O2 production, and apoptosis compared to control cells. However, prior treatment with amitriptyline significantly attenuated the nicotine-induced cell permeability, O2 production and apoptosis in podocytes. Conclusions: Asm is one of the important mediators of nicotine-induced inflammasome activation and podocyte injury. Asm may be a therapeutic target for the treatment or prevention of glomerulosclerosis associated with smoking.

Glycyrrhizin Alleviates the Damage Caused by Zearalenone and Protects the Glandular Stomach of Chickens

Zearalenone (ZEA) is a kind of mycotoxin that widely contaminates food and feed and poses a threat to poultry farming. As a natural extract, glycyrrhizin acid (GA) has antioxidant, antibacterial, and anti-inflammatory effects. Although studies have revealed the toxic effects of ZEA on the liver, the mechanism by which GA reduces ZEA's toxic protective glandular stomach remains unclear. In order to study the therapeutic effect of GA on tissue damage caused by ZEA, we conducted in vivo and in vitro experiments to compare the expression of inflammation, oxidative stress, apoptosis, and necrosis. The results showed that ZEA can induce inflammation in tissues and cells, inducing apoptosis and necrosis. In addition, GA can alleviate the toxic effects caused by ZEA and protect cells. Dietary GA significantly increased the antioxidant capacity of glandulae and inhibited the overexpression of NFκB/IκB-α and its mediated inflammatory response. Moreover, GA decreased the expression of pro-apoptotic factors and necrosis factors, thereby alleviating apoptosis and necrosis of chicken glandular stomach cells. At present, the mechanism of ZEA damage to livers and lungs has been confirmed by studies. However, there have been no studies on GA alleviating the damage caused by ZEA to the glandular stomach. Therefore, the purpose of this study was to explore the mechanism of GA alleviating the damage caused by ZEA in the glandular stomach through in vivo and in vitro experimental comparison. The results may provide some reference for the solution of feed contamination.

A mechanistic review-regulation of silica-induced pulmonary inflammation by IL-10 and exacerbation by Type I IFN

Occupational exposure to crystalline silica (CS) is known to induce silicosis, a chronic lung disease characterized by the formation of granulomas and severe lung fibrosis. Specifically, individuals exposed to low doses of CS may develop silicosis after a decade or more of exposure. Similarly, in rat silicosis models exposed to occupationally relevant doses of α-quartz, there is an initial phase characterized by minimal and well-controlled pulmonary inflammation, followed by the development of robust and persistent inflammation. During the initial phase, the inflammation provoked by α-quartz is subdued by two mechanisms. Firstly, α-quartz particles are engulfed by alveolar macrophages (AMs) of the alternatively activated (M2) subtype and interstitial macrophages (IMs), limiting their interaction with other lung cells. Secondly, the anti-inflammatory cytokine, interleukin (IL)-10, is constitutively expressed by these macrophages, further dampening the inflammatory response. In the later inflammatory phase, IL-10-dependent anti-inflammatory state is disrupted by Type I interferons (IFNs), leading to the production of pro-inflammatory cytokines in response to α-quartz, aided by lipopolysaccharides (LPS). This review delves into the complex pathways involving IL-10, LPS, and Type I IFNs in α-quartz-induced pulmonary inflammation, offering a detailed analysis of the underlying mechanisms and identifying areas for future research.

Toxicity of size separated chrysotile fibres: The relevance of the macrophage-endothelial axis crosstalk

Asbestos minerals have been widely exploited due to their physical-chemical properties, and chrysotile asbestos has accounted for about 95% of all asbestos commercially employed worldwide. The exposure to chrysotile, classified like other five amphibole asbestos species as carcinogenic to humans, represents a serious occupational and environmental hazard. Nevertheless, this mineral is still largely employed in about 65% of the countries worldwide, which still allow its "safe use". The complex mechanisms through which the mineral fibres induce toxicity are not yet completely understood. In this regard, the morphometric parameters of asbestos fibres (e.g., length, width, aspect ratio) are known for their fundamental role in determining the degree of pathogenicity. In this context, the potential toxicity of short chrysotile fibres remains widely debated due to the contradictory results from countless studies. Thus, the present study investigated the different toxicity mechanisms of two representative batches of short (length ≤5 µm) and long (length >5 µm) chrysotile fibres obtained by cryogenic milling. The fibre doses were based upon equal mass and size, since due to chrysotile ability to form bundles, it was not possible to calculate the number of fibers applied per cell. The cytotoxic, genotoxic, and pro-inflammatory potential of the two size-separated chrysotile fractions was investigated on human THP-1-derived macrophages and HECV endothelial cells, both separately and in a co-culture setup, mimicking the alveolar pro-inflammatory microenvironment, in time course experiments up to 1 week. Both chrysotile fractions displayed cytotoxic, genotoxic, and pro-inflammatory effects, with results comparable to the well-known damaging effects of crocidolite asbestos, or higher, as in the case of the longer chrysotile fraction. Furthermore, in presence of HECV, fibre-treated macrophages showed prolonged inflammation, indicating an interesting crosstalk between these cells able to sustain a low-grade chronic inflammation in the lung. In conclusion, these results help to shed light on some important open questions on the mechanisms of toxicity of chrysotile asbestos fibres.

Dual role of pyroptosis in liver diseases: mechanisms, implications, and therapeutic perspectives

Pyroptosis, a form of programmed cell death induced by inflammasome with a mechanism distinct from that of apoptosis, occurs via one of the three pathway types: classical, non-classical, and granzyme A/B-dependent pyroptosis pathways. Pyroptosis is implicated in various diseases, notably exhibiting a dual role in liver diseases. It facilitates the clearance of damaged hepatocytes, preventing secondary injury, and triggers immune responses to eliminate pathogens and damaged cells. Conversely, excessive pyroptosis intensifies inflammatory responses, exacerbates hepatocyte damage and promotes the activation and proliferation of hepatic stellate cells, accelerating liver fibrosis. Furthermore, by sustaining an inflammatory state, impacts the survival and proliferation of cancer cells. This review comprehensively summarizes the dual role of pyroptosis in liver diseases and its therapeutic strategies, offering new theoretical foundations and practical guidance for preventing and treating of liver diseases.

Stat3 Induces IL-10 and SR-A/CD204 Expression in Silica Nanoparticle-Triggered Pulmonary Fibrosis through Transactivation

Inhalation of silica dust in the workplace has been addressed as a serious occupational pulmonary disease subsequently leading to inflammation and fibrosis. Enhanced expression of IL-10 significantly contributes to the disease etiology, along with an elevated Th2-type paradigm. Previously, we showed that the exaggerated Th2-type response was also associated with consistent upregulation of Stat3 in mouse airways stimulated with silica microparticles. However, a precise understanding of silicosis in light of the IL-10/Stat3 immune axis is required. We, therefore, aimed to determine the regulatory role of IL-10 in nanosized silica (nSiO2)-induced pulmonary fibrosis in association with Stat3. Herein, we report that amorphous nSiO2 could induce pulmonary fibrosis with consistent and concomitant upregulation of IL-10, Stat3, and SR-A/CD204. Following exogenous administration of siStat3 and rIL-10, the study further confirmed that Stat3 mediates the regulation of IL-10 and SR-A/CD204 and that IL-10 could regulate its own expression in an autoregulatory loop. The ChIP assay highlighted the localization of Stat3 over two putative binding sites in the IL-10 promoter region, which subsequently resulted in the overexpression of SR-A/CD204. Conclusively, Stat3-mediated transregulation of IL-10 through an autoregulatory loop in silicosis could offer novel molecular targets for therapeutic interventions.

A comprehensive retrospect on the current perspectives and future prospects of pneumoconiosis

Pneumoconiosis is a widespread occupational pulmonary disease caused by inhalation and retention of dust particles in the lungs, is characterized by chronic pulmonary inflammation and progressive fibrosis, potentially leading to respiratory and/or heart failure. Workers exposed to dust, such as coal miners, foundry workers, and construction workers, are at risk of pneumoconiosis. This review synthesizes the international and national classifications, epidemiological characteristics, strategies for prevention, clinical manifestations, diagnosis, pathogenesis, and treatment of pneumoconiosis. Current research on the pathogenesis of pneumoconiosis focuses on the influence of autophagy, apoptosis, and pyroptosis on the progression of the disease. In addition, factors such as lipopolysaccharide and nicotine have been found to play crucial roles in the development of pneumoconiosis. This review provides a comprehensive summary of the most fundamental achievements in the treatment of pneumoconiosis with the purpose of indicating the future direction of its treatment and control. New technologies of integrative omics, artificial intelligence, systemic administration of mesenchymal stromal cells have proved useful in solving the conundrum of pneumoconiosis. These directional studies will provide novel therapeutic targets for the treatment of pneumoconiosis.

Genome-wide screen based on 2DG activated NLRP3 inflammasome reveals the priming signal of TLR2/4 to IKKβ but not IKKα

NLRP3 inflammasome activation is a pivotal area of research in innate immunity, yet the precise priming and activation signal remain unclear. In this study, we demonstrate that glycolysis inhibitor 2-Deoxy-D-glucose (2DG) triggers NLRP3-driven pyroptosis in human leukemia monocyte THP-1 cells by interfering glycosylation rather than glycolysis, which occurs independent of potassium efflux but requires the involvement of glycolysis rate-limiting enzyme PFKP. Using a CRISPR-Cas9 mediated large-scale screen, with 2DG as a new tool for probing NLRP3 activation, we identified that TLR2, rather than TLR4, initiates a rapid and robust priming signal for NLRP3 inflammasome activation. Importantly, both TLR2 and TLR4 depend entirely on MyD88, but not TRIF, for signal transduction. Furthermore, we discovered that TAK1, IKKβ and NEMO, but not IKKα, are essential for the priming signal. Additionally, we observed that deficiency in the linear ubiquitin assembly complex (LUBAC) subunits HOIP and HOIL-1, but not SHARPIN, is sufficient to inhibit 2DG-induced pyroptotic cell death. Collectively, our study reveals some common mechanism in the NLRP3 priming signals, as well as specific mechanisms upstream of NLRP3 triggered by 2DG, and underscores the potential of 2DG as a trigger to facilitate further detailed analysis of the underlying mechanisms of NLRP3 inflammasome activation. One Sentence Summary: Priming signal by IKKβ is essential for NLRP3 activation.

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.

Balanced regulation of ROS production and inflammasome activation in preventing early development of colorectal cancer

Reactive oxygen species (ROS) production and inflammasome activation are the key components of the innate immune response to microbial infection and sterile insults. ROS are at the intersection of inflammation and immunity during cancer development. Balanced regulation of ROS production and inflammasome activation serves as the central hub of innate immunity, determining whether a cell will survive or undergo cell death. However, the mechanisms underlying this balanced regulation remain unclear. Mitochondria and NADPH oxidases are the two major sources of ROS production. Recently, NCF4, a component of the NADPH oxidase complex that primarily contributes to ROS generation in phagocytes, was reported to balance ROS production and inflammasome activation in macrophages. The phosphorylation and puncta distribution of NCF4 shifts from the membrane-bound NADPH complex to the perinuclear region, promoting ASC speck formation and inflammasome activation, which triggers downstream IL-18-IFN-γ signaling to prevent the progression of colorectal cancer (CRC). Here, we review ROS signaling and inflammasome activation studies in colitis-associated CRC and propose that NCF4 acts as a ROS sensor that balances ROS production and inflammasome activation. In addition, NCF4 is a susceptibility gene for Crohn's disease (CD) and CRC. We discuss the evidence demonstrating NCF4's crucial role in facilitating cell-cell contact between immune cells and intestinal cells, and mediating the paracrine effects of inflammatory cytokines and ROS. This coordination of the signaling network helps create a robust immune microenvironment that effectively prevents epithelial cell mutagenesis and tumorigenesis during the early stage of colitis-associated CRC.

Knowledgebase-Driven Exploration and Experimental Verification of Simvastatin's Inhibitory Impact on P2X7/NLRP3 Inflammasome Pathway

Depression is a mental health disorder and is the fourth most prevalent disease. Previous studies have suggested that statins are involved in the reduction of neuroinflammation. However, the potential mechanism for this relationship is unclear. The current study aimed to elucidate this by examining the effects of simvastatin on the P2X7/NLRP3 pathway in rats exposed to chronic mild stress (CMS). To achieve this goal, a depression database was first constructed, and simvastatin was used as an input to predict potential targets using machine/deep learning methods. Interestingly, the P2X7/NLRP3 pathway was predicted as a potential target for simvastatin. Subsequently, a depression rat model was established by inducing CMS for 4 weeks. Behavioral changes were detected via a sucrose preference test and forced swim test. The depression rats were then treated with simvastatin (10 mg/kg/day) for 14 days. Following treatment, changes in behavior and the activation of the NLRP3/ASC/caspase-1 inflammasome pathway in the depression model rats were observed. The P2X7 agonist (ATP) and selective P2X7 antagonist brilliant blue G (BBG) were also used for in vivo intervention. Data from the experiment showed that treatment with simvastatin and BBG significantly reduced the depressive-like behaviors in depression model rats, as well as the protein and mRNA expression levels of P2X7 and NLRP3 inflammasome. The protein and mRNA levels of the pro-inflammatory cytokine interleukin-1β significantly increased. These results demonstrate that simvastatin exerted an antidepressant-like effect in the CMS model of rats, and this effect was dependent on the inhibition of the P2X7/NLRP3 inflammasome pathway.

From fat to fire: The lipid-inflammasome connection

Inflammasomes are multiprotein complexes that play a crucial role in regulating immune responses by governing the activation of Caspase-1, the secretion of pro-inflammatory cytokines, and the induction of inflammatory cell death, pyroptosis. The inflammasomes are pivotal in effective host defense against a range of pathogens. Yet, overt activation of inflammasome signaling can be detrimental. The most well-studied NLRP3 inflammasome has the ability to detect a variety of stimuli including pathogen-associated molecular patterns, environmental irritants, and endogenous stimuli released from dying cells. Additionally, NLRP3 acts as a key sensor of cellular homeostasis and can be activated by disturbances in diverse metabolic pathways. Consequently, NLRP3 is considered a key player linking metabolic dysregulation to numerous inflammatory disorders such as gout, diabetes, and atherosclerosis. Recently, compelling studies have highlighted a connection between lipids and the regulation of NLRP3 inflammasome. Lipids are integral to cellular processes that serve not only in maintaining the structural integrity and subcellular compartmentalization, but also in contributing to physiological equilibrium. Certain lipid species are known to define NLRP3 subcellular localization, therefore directly influencing the site of inflammasome assembly and activation. For instance, phosphatidylinositol 4-phosphate plays a crucial role in NLRP3 localization to the trans Golgi network. Moreover, new evidence has demonstrated the roles of lipid biosynthesis and trafficking in activation of the NLRP3 inflammasome. This review summarizes and discusses these emerging and varied roles of lipid metabolism in inflammasome activation. A deeper understanding of lipid-inflammasome interactions may open new avenues for therapeutic interventions to prevent or treat chronic inflammatory and autoimmune conditions.

DAG-MAG-ΒHB: A Novel Ketone Diester Modulates NLRP3 Inflammasome Activation in Microglial Cells in Response to Beta-Amyloid and Low Glucose AD-like Conditions

BACKGROUND

A neuroinflammatory disease such as Alzheimer's disease, presents a significant challenge in neurotherapeutics, particularly due to the complex etiology and allostatic factors, referred to as CNS stressors, that accelerate the development and progression of the disease. These CNS stressors include cerebral hypo-glucose metabolism, hyperinsulinemia, mitochondrial dysfunction, oxidative stress, impairment of neuronal autophagy, hypoxic insults and neuroinflammation. This study aims to explore the efficacy and safety of DAG-MAG-ΒHB, a novel ketone diester, in mitigating these risk factors by sustaining therapeutic ketosis, independent of conventional metabolic pathways.

METHODS

We evaluated the intestinal absorption of DAG-MAG-ΒHB and the metabolic impact in human microglial cells. Utilizing the HMC3 human microglia cell line, we examined the compound's effect on cellular viability, Acetyl-CoA and ATP levels, and key metabolic enzymes under hypoglycemia. Additionally, we assessed the impact of DAG-AG-ΒHB on inflammasome activation, mitochondrial activity, ROS levels, inflammation and phagocytic rates.

RESULTS

DAG-MAG-ΒHB showed a high rate of intestinal absorption and no cytotoxic effect. In vitro, DAG-MAG-ΒHB enhanced cell viability, preserved morphological integrity, and maintained elevated Acetyl-CoA and ATP levels under hypoglycemic conditions. DAG-MAG-ΒHB increased the activity of BDH1 and SCOT, indicating ATP production via a ketolytic pathway. DAG-MAG-ΒHB showed remarkable resilience against low glucose condition by inhibiting NLRP3 inflammasome activation.

CONCLUSIONS

In summary, DAG-MAG-ΒHB emerges as a promising treatment for neuroinflammatory conditions. It enhances cellular health under varying metabolic states and exhibits neuroprotective properties against low glucose conditions. These attributes indicate its potential as an effective component in managing neuroinflammatory diseases, addressing their complex progression.

Identification of markers correlating with mitochondrial function in myocardial infarction by bioinformatics

BACKGROUND

Myocardial infarction (MI), one of the most serious cardiovascular diseases, is also affected by altered mitochondrial metabolism and immune status, but their crosstalk is poorly understood. In this paper, we use bioinformatics to explore key targets associated with mitochondrial metabolic function in MI.

METHODS

The datasets (GSE775, GSE183272 and GSE236374) were from National Center for Biotechnology Information (NCBI) Gene Expression Omnibus (GEO) in conjunction with mitochondrial gene data that were downloaded from the MitoCarta 3.0 database. Differentially expressed genes (DEGs) in the dataset were screened by ClusterGVis, Weighted Gene Co-Expression Network Analysis (WGCNA) and GEO2R, and functional enrichment was performed by Gene Set Enrichment Analysis (GSEA) and Kyoto Encyclopedia of Genomes (KEGG). Then mitochondria-associated DEGs (MitoDEGs) were obtained. Protein-protein interaction (PPI) networks were constructed to identify central MitoDEGs that are strongly associated with MI. The Cytoscape and miRWalk databases were then used to predict the transcription factors and target miRNAs of the central MitoDEG, respectively. Finally, the mouse model has been established to demonstrate the expression of MitoDEGs and their association with cardiac function.

RESULTS

MitoDEGs in MI were mainly involved in mitochondrial function and adenosine triphosphate (ATP) synthesis pathways. The 10 MI-related hub MitoDEGs were then obtained by eight different algorithms. Immunoassays showed a significant increase in monocyte macrophage and T cell infiltration. According to animal experiments, the expression trends of the four hub MitoDEGs (Aco2, Atp5a1, Ndufs3, and Ndufv1) were verified to be consistent with the bioinformatics results.

CONCLUSION

Our study identified key genes (Aco2, Atp5a1, Ndufs3, and Ndufv1) associated with mitochondrial function in myocardial infarction.

First Description of the Role of the Relationship Between Serum Amyloid P Components and Nuclear Factors/Pro-Cytokines During Critical Periods of Toxoplasmic Encephalitis

Background/Objectives:Toxoplasma gondii (T. gondii), an obligate food-borne intracellular parasite, causes severe neuropathology by establishing a persistent infection in the host brain. We have previously shown that T. gondii infection induces severe neuropathology in the brain manifested by increased nitric oxide production, oxidative stress, glial activation/BBB damage, increased pro-inflammatory cytokine glia maturation factor-beta and induced apoptosis. Methods: The aim of this experimental study was to investigate the serum amyloid P (SAP) components, nuclear factor kappa B (NF-κB), interleukin-1 beta (IL-1β), caspase 1 (Casp 1), tumor necrosis factor-alpha (TNF-α) and complement 3 (C3) gene expressions on the 10th, 20th and 30th days after infection with T. gondii in the neuroimmunopathogenesis of toxoplasmic encephalitis (TE) in mouse brains by real-time quantitative polymerase chain reaction. The study also aimed to determine whether there was a correlation between the markers included in the study on these critical days, which had not previously been investigated. The mRNA expression levels of SAP components, NF-κB, IL-1β, Casp 1, TNF-α and C3 were examined. Results: The most notable outcome of this investigation was the observation that SAP components exhibited a 13.9-fold increase on day 10 post-infection, followed by a rapid decline in the subsequent periods. In addition, IL-1β expression increased 20-fold, while SAP components decreased 13-fold on day 20 after infection. Additionally, the TNF-α, Casp 1 and NF-κB expression levels were consistently elevated to above normal levels at each time point. Conclusions: This study identified SAP components, NF-κB, IL-1β, Casp 1 and TNF-α expressions as playing critical roles in TE neuroimmunopathogenesis. Furthermore, to the best of our knowledge, this is the first study to investigate SAP components during the transition from acute systemic infection to early/medium chronic and chronic infection and to explore the relationship between SAP components and other nuclear factors/pro-cytokines.

Pyroptosis the Emerging Link Between Gut Microbiota and Multiple Sclerosis

This review elucidates the pivotal role of pyroptosis, triggered by gut microbiota, in the development of multiple sclerosis (MS), emphasizing its significance within the gut-brain axis. Our comprehensive analysis of recent literature reveals how dysbiosis in the gut microbiota of MS patients-characterized by reduced microbial diversity and shifts in bacterial populations-profoundly impacts immune regulation and the integrity of the central nervous system (CNS). Pyroptosis, an inflammatory form of programmed cell death, significantly exacerbates MS by promoting the release of inflammatory cytokines and causing substantial damage to CNS tissues. The gut microbiota facilitates this detrimental process through metabolites such as short-chain fatty acids and neuroactive compounds, or self-structural products like lipopolysaccharides (LPS), which modulate immune responses and influence neuronal survival. This review highlights the potential of modulating gut microbiota to regulate pyroptosis, thereby suggesting that targeting this pathway could be a promising therapeutic strategy to mitigate inflammatory responses and preserve neuronal integrity in patients with MS.

Design Principles for Immunomodulatory Biomaterials

The immune system is imperative to the survival of all biological organisms. A functional immune system protects the organism by detecting and eliminating foreign and host aberrant molecules. Conversely, a dysfunctional immune system characterized by an overactive or weakened immune system causes life-threatening autoimmune or immunodeficiency diseases. Therefore, a critical need exists to develop technologies that regulate the immune system to ensure homeostasis or treat several diseases. Accumulating evidence shows that biomaterials─artificial materials (polymers, metals, ceramics, or engineered cells and tissues) that interact with biological systems─can trigger immune responses, offering a materials science-based strategy to modulate the immune system. This Review discusses the expanding frontiers of biomaterial-based immunomodulation, focusing on principles for designing these materials. This Review also presents examples of immunomodulatory biomaterials, which include polymers and metal- and carbon-based nanomaterials, capable of regulating the innate and adaptive immune systems.

Molecular mechanisms of zymosan-induced inflammasome activation in macrophages

Zymosan is a β-glucan-rich component derived from the cell walls of Saccharomyces cerevisiae extensively used in research for its potent immunomodulatory properties. It can prompt inflammatory responses such as peritonitis and arthritis, and is particularly used to study the immune response to fungal particles. Although the zymosan induced-release of the proinflammatory cytokine IL-1β by macrophages is an essential mechanism for combating fungal infection and inducing inflammation, the exact processes leading to its release remain not well understood. In this study, we uncover the intracellular mechanisms involved in zymosan induced-release of active IL-1β by peritoneal macrophages. Zymosan initiates pro-IL-1β formation through TLR2/MyD88 activation; however, Dectin-1 activation only amplify the conversion of pro-IL-1β into its active form. The conversion of inactive to active IL-1β upon zymosan stimulation depends on the NLRP3, ASC, and caspase-1 driven by the decrease in intracellular potassium ions. Notably, zymosan-induced activation of caspase-1 does not require phagocytosis. Instead, zymosan induces a rapid drop in the intracellular ATP concentration, which occurs concomitant with caspase-1 and IL-1β activation. Accordingly, disruption of glycolytic flux during zymosan stimulation promotes an additional reduction of intracellular ATP and concurrently amplifies the activation of caspase-1 and IL-1β. These results reveal that fungal recognition by macrophages results in a metabolic dysfunction, leading to a decrease of intracellular ATP associated with inflammasome activation.

Bufei Huoxue capsule alleviates silicosis by inhibiting the activation of nucleotide-like receptor containing pyrin domain 3 inflammasome and macrophages polarization based on network pharmacology

OBJECTIVE

To predict the targets of Bufei Huoxue capsule (, BFHX) using network pharmacology analysis and to explore its effects and functional targets in a silicotic rat model.

METHODS

The drug and disease targets were correlated through network pharmacology analysis to explore the targets and signaling pathways of BFHX affecting silicosis. NR8383 cells were cultured to verify the core genes and pathways. A rat model of silicosis was established to verify whether the mechanism behind SiO2-caused pulmonary fibrosis was alleviated by BFHX (0.82 g/kg) and how it affected key targets and pathways.

RESULTS

Overlapping BFHX and silicotic gene targets produced 159 interactive targets, and 55 were screened by network topology analysis. The results of gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses suggested that BFHX could affect silicosis through the nucleotide-like receptor containing pyrin domain 3 (NLRP3) inflammasome. In NR8383 cells, the expression of core genes related to the NLRP3 inflammasome could be inhibited by BFHX treatment. BFHX reduced the degree of alveolitis and collagen deposition, attenuating pulmonary fibrosis in SiO2-induced rat model. Pulmonary macrophage pyroptosis after SiO2 exposure was observed under transmission electron microscopy. BFHX alleviated the morphological characteristics of pyroptosis. BFHX also reduced the expression of NLRP3, caspase-1, interleukin-1 beta (IL-1β), IL-18, IL-6, and tumor necrosis factor-alpha in lung tissues of silicotic rat model. BFHX affected the K ion content in bronchoalveolar lavage fluid when assessed by energy dispersive spectrometer testing. The expression of CD68+ and CD206+ were also reduced after BFHX intervention.

CONCLUSION

NOD-like receptor signaling is vital for BFHX's effects on silicosis. It exerts anti-pulmonary fibrosis effects by inhibiting pulmonary macrophage pyroptosis and polarization through NLRP3 inflammasome activation.

Mechanism of Resveratrol on LPS/ATP-induced pyroptosis and inflammatory response in HT29 cells

Pyroptosis plays an important role in maintenance of intestinal homeostasis, the abnormal activation of NOD-like receptor thermal protein domain-associated protein 3 (NLRP3) inflammasome can promote the event and development of ulcerative colitis (UC). Its protective effects such as inhibiting pyroptosis in various inflammation-related diseases have been demonstrated, but whether resveratrol (RES) can also alleviate the progression of the disease by inhibiting pyroptosis in UC and the mechanism have rarely been studied. In this study, lipopolysaccharide (LPS) combined with adenosine triphosphate (ATP) was used to induce HT29 human colon cancer cells to construct an intestinal epithelial cell pyroptosis and inflammation model in vitro to investigate the anti-inflammatory effect of RES, reveal the regulatory mechanism of RES on pyroptosis, and provide a new theoretical basis for the treatment of UC. In vitro experiences, HT29 cells were dividing into control group, LPS/ATP group, RES low-dose group, RES high-dose group, NF-κB inhibitor pyrrolidine dithiocarbamate group (PDTC group), and LPS/ATP+PDTC group. The mRNA expressions of pyroptosis-related indicators such as NLRP3, apoptosis-associated speck-like protein containing CARD (ASC), Caspase-1(CASP1), IL-18, IL-1β, and inflammatory factors such as TNF-α and IL-6 were detected by qRT-PCR. The protein expressions of pyroptosis-related indicators NLRP3, ASC, CASP1, IL-18, IL-1β, NF-κB-p65 in the nucleus, and IκBα and p-IκBα in the cytoplasm were detected by Western blot. Immunofluorescence saw the distribution and expression of NLRP3, ASC and NF-κB-p65 protein in each group. The morphology and degree of pyroptosis in each group were observed by transmission electron microscope. The results showed that compared with the control group, the pyroptosis-related proteins including NLRP3, ASC, CASP1, IL-18, IL-1β, and inflammatory factors including TNF-α and IL-6 in the LPS/ATP group were increased, and LPS/ATP activated the activity of NF-κB signaling pathway. Compared with the LPS/ATP group, RES downregulated the expression of pyroptosis-related proteins and inflammatory factors in HT29 cells, and inhibited the activation of the NF-κB signaling pathway in HT29 cells pyroptosis. RES down-regulates the pyroptosis of HT29 cells induced by LPS/ATP and the expression of pyroptosis-related indicators NLRP3, ASC, CASP1, IL-18, IL-1β and inflammatory factors TNF-α and IL-6 in the inflammatory response and inhibits the occurrence of pyroptosis. The mechanism is related to the inhibition of NF-κB pathway activity.