Gout-associated uric acid crystals activate the NALP3 inflammasome

Anti-inflammatory effect of Plantago asiatica crude extract in rat gout arthritis model

Plantago asiatica L., a perennial herb in the family Plantaginaceae, has been shown to impart several pharmacologic activities, including anti-oxidative, anti-inflammatory, and diuretic effects. In the study here, the anti-gout(y) arthritis (GA) effects of a crude extract from P. asiatica L. (PAE) were investigated in a rat GA model. For this, PAE was prepared by ethanol extraction and analyzed for phytochemicals by RP-HPLC and Q-TOF-MS. Thereafter, potential therapeutic effects of the PAE were investigated in rats; Wistar rats (male, 8 wk-of-age) were randomly allocated into four groups (n = 9/group) and intra-articularly injected with 3 mg monosodium urate (MSU) in saline solution to establish a GA model. For the study, rats received oral dosings of 0.3 mg colchicine/kg or 1 g PAE/kg (w/w) before and after gout was established. At fixed times after the treatments, assessment of joint swelling ratios and pathological changes in the joints, as well as of select cytokine expression in the blood, was done. RP-HPLC results showed the PAE contained at least 8 'active' ingredients, with plantamajoside, verbascoside, and cymaroside being the most abundant. In comparison to in control rats, MSU induced joint space narrowing, ankle joint swelling, and increased levels of pro-inflammatory interleukin (IL)-1β, IL-17a, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ, and reductions in anti-inflammatory IL-10 in the blood. PAE treatment significantly reversed patho- genic joint space narrowing and swelling, reversed the MSU-induced changes in inflammatory factors, and in general imparted effects very similar to those seen with colchicine (COL; known non-steroidal anti-inflammatory drug for clinical treatment of GA). Collectively, these findings provide experimental evidence supporting the potential applicability of PAE to treat gouty arthritis.

Nobiletin ameliorates monosodium urate-induced gouty arthritis in mice by enhancing AMPK/mTOR-mediated autophagy to inhibit NF-κB/NLRP3 inflammasome activation

BACKGROUND

Gouty arthritis (GA) is a common rheumatic disease caused by the release of monosodium urate crystal (MSU) deposits into joint space. Nobiletin is a polymethoxylated flavonoid isolated from citrus fruits and has many beneficial activities. This study aimed to elucidate the therapeutic efficacy of nobiletin in GA and to reveal its potential mechanisms.

METHODS

Phorbol-12-myristate-13-acetate (PMA)-differentiated THP-1 macrophages were primed with lipopolysaccharide (LPS) and then stimulated with MSU crystals in the presence or absence of nobiletin. Cell viability as well as the levels of proinflammatory cytokines, pathway-related proteins, NLRP3 inflammasomes, and autophagy-related proteins were evaluated. MSU was used to induce GA in mice. Hematoxylin-eosin staining was conducted to assess histological morphology changes. Immunofluorescence staining was performed to measure LC3 expression in THP-1 cells and ankle joint tissues.

RESULTS

For in vitro analysis, nobiletin reduced LPS and MSU-induced cell viability inhibition. Additionally, nobiletin inhibited inflammation and NF-κB/NLRP3 pathway in THP-1 cells. Moreover, nobiletin inhibited the activation of NLRP3 inflammasome by promoting AMPK/mTOR-mediated autophagy. For in vivo analysis, nobiletin attenuated MSU-induced GA in mice. Additionally, nobiletin suppressed inflammation and NF-κB/NLRP3 pathway and promoted tissue autophagy in GA mice.

CONCLUSION

Nobiletin prevents MSU-induced GA in mice by inhibiting NF-κB/NLRP3 inflammasome activation through AMPK/mTOR-mediated autophagy.

Neuronal regulated cell death in aging-related neurodegenerative diseases: key pathways and therapeutic potentials

Regulated cell death (such as apoptosis, necroptosis, pyroptosis, autophagy, cuproptosis, ferroptosis, disulfidptosis) involves complex signaling pathways and molecular effectors, and has been proven to be an important regulatory mechanism for regulating neuronal aging and death. However, excessive activation of regulated cell death may lead to the progression of aging-related diseases. This review summarizes recent advances in the understanding of seven forms of regulated cell death in age-related diseases. Notably, the newly identified ferroptosis and cuproptosis have been implicated in the risk of cognitive impairment and neurodegenerative diseases. These forms of cell death exacerbate disease progression by promoting inflammation, oxidative stress, and pathological protein aggregation. The review also provides an overview of key signaling pathways and crosstalk mechanisms among these regulated cell death forms, with a focus on ferroptosis, cuproptosis, and disulfidptosis. For instance, FDX1 directly induces cuproptosis by regulating copper ion valency and dihydrolipoamide S-acetyltransferase aggregation, while copper mediates glutathione peroxidase 4 degradation, enhancing ferroptosis sensitivity. Additionally, inhibiting the Xc- transport system to prevent ferroptosis can increase disulfide formation and shift the NADP + /NADPH ratio, transitioning ferroptosis to disulfidptosis. These insights help to uncover the potential connections among these novel regulated cell death forms and differentiate them from traditional regulated cell death mechanisms. In conclusion, identifying key targets and their crosstalk points among various regulated cell death pathways may aid in developing specific biomarkers to reverse the aging clock and treat age-related neurodegenerative conditions.

Discovery of a novel Thiazole amide inhibitor of Inflammasome and Pyroptosis pathways

Upon the activation of inflammasomes, inflammatory caspases cleave and activate gasdermin D (GSDMD), leading to pore formation that causes cell membrane rupture and amplifies downstream inflammatory responses. Dysregulated inflammasome activation and pyroptosis signaling pathways are implicated in numerous inflammatory diseases. In our work, a set of novel thiazole amide compounds with inhibitory activity against NLRP3 inflammasome-induced pyroptosis was identified. Of all the compounds tested, compound 21 demonstrated the most potent anti-pyroptotic effects. It suppressed GSDMD cleavage and decreased IL-1β and lactate dehydrogenase (LDH) release in a concentration-dependent manner. Compound 21 bound to NLRP3 protein and increased the thermal stability of NLRP3 concentration-dependently. The molecular docking and dynamics simulations revealed that compound 21 binds to the NLRP3 protein's active site, suppressing inflammasome activation. Further investigations showed that compound 21 also partially blocked upstream NF-κB signaling and downstream GSDMD N-terminal domain (GSDMD-NT) oligomerization, which explains its broad inhibitory effects on pyroptosis driven by multiple inflammasomes. Overall, this study presents a promising thiazole amide compound with inhibitory activity against inflammasome activation and subsequent pyroptosis, warranting further exploration.

Broxyquinoline targets NLRP3 to inhibit inflammasome activation and alleviate NLRP3-associated inflammatory diseases

The NLR family pyrin domain-containing 3 (NLRP3) inflammasome is responsible for various pathogenic and non-pathogenic damage signals and plays a critical role in host defense against pathogens and physiological damage. However, inflammasome activation and its subsequent effects also lead to a variety of inflammatory diseases. In this study, we identified broxyquinoline, an FDA-approved antimicrobial drug, as a effective NLRP3 inflammasome inhibitor. Broxyquinoline suppressed NLRP3 inflammasome-dependent interleukin-1β (IL-1β) release, but did not affect NLRC4 or AIM2 inflammasome activation. Mechanistically, broxyquinoline directly targets Arg165 of NLRP3 protein, thus preventing NEK7-NLRP3 interaction, NLRP3 oligomerization, and ASC speck formation, without affecting the NF-κB pathway. Consequently, broxyquinoline significantly attenuated the progression of monosodium urate (MSU)-induced peritonitis and myelin oligodendrocyte glycoprotein (MOG35-55)-induced experimental autoimmune encephalomyelitis (EAE) in murine models. In conclusion, we demonstrated that broxyquinoline directly targets the NLRP3 protein to suppress the activation of NLRP3 inflammasome and provide a promising therapeutic agent for NLRP3 inflammasome-associated diseases.

Phytochemical characterization and pharmacological mechanisms of Huazhuo Sanjie Chubi Decoction in treating gouty arthritis: A multivariant approach

ETHNOPHARMACOLOGICAL RELEVANCE

Huazhuo Sanjie Chubi Decoction (HSCD), a Chinese herbal formula, is traditionally used for the treatment of spleen deficiency with dampness accumulation and is commonly used to treat gouty arthritis (GA). However, the potential active compounds and mechanisms of HSCD remain unclear.

AIM OF THE STUDY

To elucidate the key bioactive compounds and pharmacological mechanisms of HSCD in treating GA.

MATERIALS AND METHODS

The chemical compounds in HSCD were qualitatively and quantitatively analyzed using ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Network pharmacology and molecular docking were employed to identify key active compounds and associated molecular pathways. Monosodium urate (MSU)-induced RAW264.7 macrophages and GA rat model were used to explore the potential therapeutic effects and mechanisms of HSCD in treating GA.

RESULTS

UPLC-MS/MS identified 184 compounds in HSCD, with 28 key compounds quantified. Network pharmacology revealed that verbenalin, limonin, and quercitrin are strongly associated with the molecular mechanisms of HSCD in treating GA via the PI3K-AKT signaling pathway. These compounds exhibited strong binding affinity to PI3K and AKT proteins. In RAW264.7 cells, HSCD and the three identified compounds dose-dependently reduced inflammation by inhibiting nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3), cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). They also downregulated both the PI3K-AKT and apoptosis signaling pathways. In rats, HSCD exerted therapeutic effects against acute GA by alleviating swelling and pathological damage to the ankle joints. Moreover, the molecular mechanisms in vivo were confirmed to be associated with the PI3K-AKT and apoptosis signaling pathways.

CONCLUSION

This study employed a multivariant approach to demonstrate the main bioactive compounds and molecular mechanisms of HSCD in treating GA, thereby supporting its traditional use.

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

INTRODUCTION

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

AREAS COVERED

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

EXPERT OPINION

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

Caspases: structural and molecular mechanisms and functions in cell death, innate immunity, and disease

Caspases are critical regulators of cell death, development, innate immunity, host defense, and disease. Upon detection of pathogens, damage-associated molecular patterns, cytokines, or other homeostatic disruptions, innate immune sensors, such as NLRs, activate caspases to initiate distinct regulated cell death pathways, including non-lytic (apoptosis) and innate immune lytic (pyroptosis and PANoptosis) pathways. These cell death pathways are driven by specific caspases and distinguished by their unique molecular mechanisms, supramolecular complexes, and enzymatic properties. Traditionally, caspases are classified as either apoptotic (caspase-2, -3, -6, -7, -8, -9, and -10) or inflammatory (caspase-1, -4, -5, and -11). However, extensive data from the past decades have shown that apoptotic caspases can also drive lytic inflammatory cell death downstream of innate immune sensing and inflammatory responses, such as in the case of caspase-3, -6, -7, and -8. Therefore, more inclusive classification systems based on function, substrate specificity, or the presence of pro-domains have been proposed to better reflect the multifaceted roles of caspases. In this review, we categorize caspases into CARD-, DED-, and short/no pro-domain-containing groups and examine their critical functions in innate immunity and cell death, along with their structural and molecular mechanisms, including active site/exosite properties and substrates. Additionally, we highlight the emerging roles of caspases in cellular homeostasis and therapeutic targeting. Given the clinical relevance of caspases across multiple diseases, improved understanding of these proteins and their structure-function relationships is critical for developing effective treatment strategies.

Unraveling the effects of uric acid on endothelial cells: A global proteomic study

This work aims to understand how normouricemic levels of uric acid can induce endothelial dysfunction seeking global proteomic alterations in Human Umbilical Vein cells (HUVEC). It reveals significant alterations in redox-sensitive and antioxidant proteins, chaperones, and proteins associated with cell migration and adhesion in response to uric acid exposure. Monitoring cellular oxidation with the roGFP2-Grx1 probe proved increased oxidation levels induced by uric acid, which can be attenuated by peroxidasin (PXDN) inhibition, suggesting a regulatory role for PXDN in mitigating oxidative stress induced by uric acid. As a consequence of uric acid oxidation and the formation of reactive intermediate, we identified adducts in proteins (+140 kDa) in a novel post-translation modification named uratylation. Increased misfolded protein levels and p62 aggregation were also found, indicating disturbances in cellular proteostasis. Furthermore, uric acid promoted monocyte adhesion and upregulated ICAM and VCAM protein levels, implicating a pro-inflammatory response in endothelial cells. These findings provide critical insights into the molecular mechanisms underlying vascular damage associated with uric acid.

Inflammasome Activation and Neutrophil Extracellular Traps in Atherosclerosis

The deposition of cholesterol containing cholesterol crystals and the infiltration of immune cells are features of atherosclerosis. Although the role of cholesterol crystals in the progression of atherosclerosis have long remained unclear, recent studies have clarified the involvement of cholesterol crystals in inflammatory responses. Cholesterol crystals activate the NLRP3 inflammasome, a molecular complex involved in the innate immune system. Activation of NLRP3 inflammasomes in macrophages cause pyroptosis, which is accompanied by the release of inflammatory cytokines such as IL-1β and IL-1α. Furthermore, NLRP3 inflammasome activation drives neutrophil infiltration into atherosclerotic plaques. Cholesterol crystals trigger NETosis against infiltrated neutrophils, a form of cell death characterized by the formation of neutrophil extracellular traps (NETs), which, in turn, prime macrophages to enhance inflammasome-mediated inflammatory responses. Colchicine, an anti-inflammatory drug effective in cardiovascular disease, is expected to inhibit cholesterol crystal-induced NLRP3 inflammasome activation and neutrophil infiltration. In this review, we illustrate the reinforcing cycle of inflammation that is amplified by inflammasome activation and NETosis.

Allopurinol abates hepatocellular carcinoma in rats via modulation of NLRP3 inflammasome and NF-κB pathway

The present research was performed to examine the possible capability of allopurinol to prevent developing hepatocellular carcinoma (HCC) and to explore the fundamental mechanisms that control the hepatoprotective effect considering the enormous impact of HCC on patients' quality of life. Male Sprague Dawely rats were given i.p. injection of thioacetamide (TAA) (200 mg/kg) twice a week for 16 weeks in order to induce HCC. The histological analysis and assessment of the serum levels of liver function indicators verified the development of HCC. Two regimens of allopurinol (100 mg/kg, p.o.) were used; the first involved giving it concurrently with TAA from week 13 to week 16, and the second regimen started from week 9 to week 16. Chronic TAA damage was associated with considerable overexpression of the profibrogenic cytokine TGF-β, degradation and nuclear translocation of NF-κB, which released a number of inflammatory mediators, and upregulation of the NLRP3/caspase1 pathway. Administration of allopurinol demonstrated considerable enhancements in liver function and oxidative balance. Moreover, pathological characteristics like cirrhosis, dysplastic changes, and HCC nodules were greatly diminished. Allopurinol via suppressing TGF-β expression, inhibiting NF-κB nuclear translocation, and restricting inflammatory NLRP3/caspase1/IL-1β pathway was able to protect against TAA-induced liver damage, and it could be a promising therapy for HCC.

Adaptations in mitochondrial quality control and interactions with innate immune signaling within skeletal muscle: A narrative review

Skeletal muscle health and function are essential determinants of metabolic health, physical performance, and overall quality of life. The quality of skeletal muscle is heavily dependent on the complex mitochondrial reticulum that contributes toward its unique adaptability. It is now recognized that mitochondrial perturbations can activate various innate immune pathways, such as the nucleotide-binding oligomerization domain (NOD)-like receptor protein 3 (NLRP3) inflammasome complex by propagating inflammatory signaling in response to damage-associated molecular patterns (DAMPs). The NLRP3 inflammasome is a multimeric protein complex and is a prominent regulator of innate immunity and cell death by mediating the activation of caspase-1, pro-inflammatory cytokines interleukin-1β and interleukin-18 and pro-pyroptotic protein gasdermin-D. While several studies have begun to demonstrate the relationship between various mitochondrial DAMPs (mtDAMPs) and NLRP3 inflammasome activation, the influence of various metabolic states on the production of these DAMPs and subsequent inflammatory profile remains poorly understood. This narrative review aimed to address this by highlighting the effects of skeletal muscle use and disuse on mitochondrial quality mechanisms including mitochondrial biogenesis, fusion, fission and mitophagy. Secondly, this review summarized the impact of alterations in mitochondrial quality control mechanisms following muscle denervation, aging, and exercise training in relation to NLRP3 inflammasome activation. By consolidating the current body of literature, this work aimed to further the understanding of innate immune signaling within skeletal muscle, which can highlight areas for future research and therapeutic strategies to regulate NLRP3 inflammasome activation during divergent metabolic conditions.

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.

Innate immune sensor NLRP3 drives PANoptosome formation and PANoptosis

Inflammasomes are multiprotein innate immune complexes formed in response to infections, tissue damage, or cellular stress that promote the maturation and release of IL-1β/IL-18 and are implicated in lytic cell death. The NLRP3 inflammasome is canonically activated by an initial priming event followed by an activation stimulus, leading to rapid cell death that occurs through caspase-1 (CASP1) and gasdermin D (GSDMD) activation, called pyroptosis. CASP1- and GSDMD-deficient cells are protected from the rapid LPS plus ATP-induced pyroptosis. However, innate immune responses physiologically occur over time, extending beyond minutes to hours and days. Therefore, in this study, we assessed lytic cell death beyond the early timepoints. While cells lacking the innate immune sensor NLRP3 were protected from cell death induced by the canonical NLRP3 trigger, LPS priming and ATP stimulation (LPS plus ATP), for extended time, CASP1- and GSDMD-deficient cells started to lyse in a time-dependent manner after 2 h. Nevertheless, robust IL-1β and IL-18 release was still dependent on CASP1 activation. These data suggested that NLRP3 engages an additional innate immune, lytic cell death pathway. Indeed, LPS plus ATP induced the activation of caspases and RIPKs associated with PANoptosis in WT cells, and cells deficient in PANoptosis machinery were protected from cell death for extended times. A PANoptosome complex containing NLRP3, ASC, CASP8, and RIPK3 was observed by microscopy in WT, as well as CASP1- or GSDMD-deficient, cells by 30 min post-stimulation. Overall, these findings highlight the central role of NLRP3 as a PANoptosome sensor. Given the physiological role of innate immune cell death, PANoptosis, in health and disease, our study emphasizes the importance of a comprehensive understanding of PANoptosomes, and their components, as therapeutic targets.

Current and future role of CT and advanced CT applications in inflammatory arthritis in the clinic and trials

Computed tomography (CT) has traditionally been underutilized in the imaging of inflammatory arthritis due to its limitations in assessing soft tissue inflammation and concerns over radiation exposure. However, recent technological advancements have positioned CT as a more viable imaging modality for arthritis, offering high specificity and sensitivity in detecting structural bone changes. However, advances in ultra-low-dose CT protocols and AI-driven image reconstruction have significantly reduced radiation exposure while maintaining diagnostic quality. Dynamic CT and spectral CT techniques, including dual-energy CT (DECT), have broadened CT's application in assessing dynamic joint instabilities and visualizing inflammatory changes through material-specific imaging. Techniques such as CT subtraction imaging and iodine mapping have enhanced the detection of active soft-tissue inflammation, virtual non-calcium reconstructions, and the detection of bone marrow edema. Possible CT applications span various forms of arthritis, including gout, calcium pyrophosphate deposition disease (CPPD), psoriatic arthritis, and axial spondyloarthritis. Beyond its diagnostic capabilities, CT's ability to provide detailed structural assessment positions is a valuable tool for monitoring disease progression and therapeutic response, particularly in clinical trials. While MRI remains superior for soft tissue evaluation, CT's specificity for bone-related changes and its potential for integration into routine arthritis management warrant further exploration and research. This review explores the current and emerging roles of CT in arthritis diagnostics, with a focus on novel applications and future potential.

Emulsion adjuvant-induced uric acid release modulates optimal immunogenicity by targeting dendritic cells and B cells

Squalene-based emulsion (SE) adjuvants like MF59 and AS03 are used in protein subunit vaccines against influenza virus (e.g., Fluad, Pandemrix, Arepanrix) and SARS-CoV-2 (e.g., Covifenz, SKYCovione). We demonstrate the critical role of uric acid (UA), a damage-associated molecular pattern (DAMP), in triggering immunogenicity by SE adjuvants. In mice, SE adjuvants elevated DAMP levels in draining lymph nodes. Strikingly, inhibition of UA synthesis reduced vaccine-induced innate immunity, subsequently impairing optimal antibody and T cell responses. In vivo treatment with UA crystals elicited partial adjuvant effects. In vitro stimulation with UA crystals augmented the activation of dendritic cells (DCs) and B cells and altered multiple pathways in these cells, including inflammation and antigen presentation in DCs and cell proliferation in B cells. In an influenza vaccine model, UA contributed to protection against influenza viral infection. These results demonstrate the importance of DAMPs, specifically the versatile role of UA in the immunogenicity of SE adjuvants, by regulating DCs and B cells.

Low Serum Uric Acid Levels are Associated with Severe Diabetic Foot Infection: A Cross-Sectional Study from China

Diabetic foot ulcers (DFUs) are among the most serious complications of diabetes which are associated with high disability and mortality rates. This study aims to investigate the associations between uric acid (UA) levels and diabetic foot ulcer (DFU) characteristics. In total, 1820 participants with DFUs were included in this study; 192 and 1628 participants were included in the hyperuricemia group (HUA, UA > 420 µmol/L) and the nonhyperuricemia group (NHUA, UA ≤420 µmol/L), respectively. The NHUA group was divided into a middle-UA subgroup (SMUA, 420 µmol/L ≥ UA ≥ 180 µmol/L; 304 individuals) and a low-UA subgroup (SLUA, UA <180 µmol/L; 1324 individuals). There were no significant differences in the rates of deep ulcers, severe infection or amputation between NHUA and HUA. In univariate analysis of subgroups, the differences in the rates of deep ulcers, severe infection and amputation were significant. After adjusting for confounders (sex, fasting glucose level, diabetes duration, eGFR, deep ulcers and severe infection) in multivariate analysis, the severe infection rate (OR = 4.0, 95%CI 1.6-10.0, P < 0.01) was still significantly greater in the SLUA group than in the SMUA group while the rate of deep ulcers (OR =2.4, 95%CI 1.0-6.1, P = 0.06) and amputation (OR =1.1, 95%CI 0.3-4.3, P = 0.91) showed non-statistical difference. UA levels below 180 µmol/L can be a risk factor for severe infection in DFUs.

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.

RAGE deficiency obstructs high uric acid-induced oxidative stress and inflammatory response

Hyperuricemia is a metabolic disorder primarily associated with gout and implicated in various metabolic inflammatory diseases. While the role of monosodium urate crystals triggering inflammation has been well-documented, recent findings suggest that soluble high uric acid (HUA) also induces pro-inflammatory cytokine production in human monocytes. However, the comprehensive effects of HUA levels on macrophage dysfunction and the underlying mechanisms remain underexplored. This study employs urate oxidase knockout (UOX-KO) and receptor for advanced glycation end products deficiency (RAGE-/-) mouse models to elucidate macrophage function and its mechanistic pathways. Our results demonstrate that HUA promotes M1 polarization and migration of macrophages while impairing their phagocytic ability. This process is mediated through the high mobility group box 1 (HMGB1)-RAGE- ROS axis. Notably, RAGE deficiency in bone marrow-derived cells partially mediates these effects. Pathologically, elevated HMGB1 and monocyte chemoattractant protein 1 levels in pancreatic islets increases macrophage infiltration in UOX-KO mice. Treatment with the FPS-ZM1, as a pharmacological RAGE inhibitor, effectively decreases serum UA levels, ameliorates islet inflammation and insulin resistance. These findings suggest that soluble HUA serves as a pro-inflammatory trigger through the HMGB1-RAGE-ROS axis, and that RAGE inhibition may mitigate these effects by decreasing inflammatory macrophage infiltration in the islets. Additionally, the influence of UA on macrophages extends beyond gout, potentially contributing to the pathogenesis of other metabolic inflammatory conditions, such as atherosclerosis, non-alcoholic steatohepatitis, obesity, and hyperlipidemia.

Cholesterol Embolic Renal Disease: Experience of a Large Healthcare System

Context. To determine the clinical-pathological features associated with cholesterol embolic renal disease, and review of literature. Design. This retrospective case series includes patients with cholesterol embolic renal disease (10 of 3087 kidney biopsies) who were diagnosed at Northwell Health, New York, between July 2017 and October 2022. Results. Cholesterol embolic renal disease is a rare disease with a prevalence of 0.32%. Four of 10 patients had intravascular interventional radiology procedures within 6 months prior to kidney biopsy. Four patients had remote interventional radiology history (6 months to 4 years). Seven patients presented with acute kidney injury; 3 patients underwent renal biopsy due to proteinuria. The average baseline creatinine was 2.0 ± 0.9 mg/dL; the creatinine at kidney biopsy and at follow-up was 4.3 ± 3.0 mg/dL and 2.8 ± 1.3 mg/dL, respectively. Eight patients had elevated serum eosinophil counts. Three patients died (mortality rate 30%) in an average follow-up of 4 months (range: 1-10 months). One patient progressed to end-stage kidney disease. The presence of cholesterol clefts is a hallmark of atherosclerotic emboli. Cholesterol clefts were present on the specimen for light microscopy (H&E and special stains) in 9 biopsies; 7 patients had cholesterol clefts in vascular lumens and/or walls. Cholesterol clefts were present on semi-thin sections for electron microscopy examination in 4 biopsies. One patient had cholesterol clefts present in semi-thin sections only. Conclusions. The clinical manifestation of cholesterol embolic renal disease in patients without recent intravascular interventional radiology history can be indolent but is associated with high mortality. Careful examination of all levels with light microscopy, including the perirenal tissue, and semi-thin sections can increase the detection rate of cholesterol embolic renal disease.

Association between rheumatoid arthritis and hyperuricemia among adults: a cross-sectional study based on NHANES data

OBJECTIVES

This study aimed to explore the relationship between rheumatoid arthritis (RA) and hyperuricemia among adults.

METHOD

All the data were from the National Health and Nutrition Examination Survey (NHANES 1997-2018) database. Linear regression, logistic regression, and restricted cubic spline (RCS) analyses were used to investigate the association between RA and hyperuricemia. Subgroup analysis and interaction tests were conducted to assess the influence of various subgroups on their association.

RESULTS

This study included 41,460 patients, among whom 2603 had RA. The RA group had higher uric acid levels compared with the non-RA group (P < 0.001). Linear regression showed that RA was significantly related to uric acid levels among several adjusted models (all P < 0.05). Logistic regression analysis also indicated the independent association between RA and hyperuricemia in a positive relationship (P < 0.05). Subgroup analysis revealed significant association in the subgroups of females, age ≥ 60 years, non-Hispanics, individuals with hypertension and antihypertensive drugs use, and those with BMI ≥ 30 kg/m2 (all P < 0.05). The interaction test showed that there was no interaction effect between baseline features and RA (all interaction P > 0.05). RCS analysis further found that the course of RA, rather than the age of diagnosis, was related to hyperuricemia (P < 0.05). Furthermore, we found that the association between RA and hyperuricemia was mainly observed in populations with 15-30-year course of RA (P < 0.05).

CONCLUSIONS

RA was associated with hyperuricemia and their association was still stable even after adjusting for several variables, suggesting that uric acid levels should be routinely tested to detect hyperuricemia at an early stage in patients with RA. Key Points • Revealing association between rheumatoid arthritis (RA) and hyperuricemia risk: This study initially explored the association between RA and hyperuricemia, finding that RA was positively related to the higher uric acid levels and hyperuricemia risk. • Reflecting the role of RA course on their association: Our study found that their association was mainly observed in population with RA course of 15-30 years.

An objective diagnosis of gout and calcium pyrophosphate deposition disease with machine learning of Raman spectra acquired in a point-of-care setting

OBJECTIVE

Raman spectroscopy is proposed as a next-generation method for the identification of monosodium urate (MSU) and calcium pyrophosphate (CPP) crystals in synovial fluid. As the interpretation of Raman spectra requires specific expertise, the method is not directly applicable for clinicians. We developed an approach to demonstrate that the identification process can be automated with the use of machine learning techniques. The developed system is tested in a point-of-care-setting at our outpatient rheumatology department.

METHODS

We collected synovial fluid samples from 446 patients with various rheumatic diseases from three centres. We analysed all samples with our Raman spectroscope and used 246 samples for training and 200 samples for validation. Trained observers classified every Raman spectrum as MSU, CPP or other. We designed two one-against-all classifiers, one for MSU and one for CPP. These classifiers consisted of a principal component analysis model followed by a support vector machine.

RESULTS

The accuracy for classification of CPP using the 2023 ACR/EULAR CPPD classification criteria was 96.0% (95% CI: 92.3, 98.3), while the accuracy for classification of MSU using the 2015 ACR/EULAR gout classification criteria was 92.5% (95% CI: 87.9, 95.7). Overall, the accuracy for classification of pathological crystals was 88.0% (95% CI: 82.7, 92.2). The model was able to discriminate between pathological crystals, artifacts and other particles such as microplastics.

CONCLUSION

We here demonstrate that potentially complex Raman spectra from clinical patient samples can be successfully classified by a machine learning approach, resulting in an objective diagnosis independent of the opinion of the medical examiner.

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.

Tubulin targeting agents and their implications in non-cancer disease management

Microtubules act as molecular 'tracks' for the intracellular transport of accessory proteins, enabling them to assemble into various larger structures, such as spindle fibres formed during the cell cycle. Microtubules provide an organisational framework for the healthy functioning of various cellular processes that work through the process of dynamic instability, driven by the hydrolysis of GTP. In this role, tubulin proteins undergo various modifications, and in doing so modulate various healthy or pathogenic physiological processes within cells. In this review, we provide a detailed update of small molecule chemical agents that interact with tubulin, along with their implications, specifically in non-cancer disease management.

Familial Mediterranean fever with sigmoid colon stricture

We describe a case of familial Mediterranean fever (FMF) with sigmoid colon stricture. The patient, a woman in her 30 s, had a 12-year history of ileocolitis-type Crohn's disease. The colonoscope could not pass because of the sigmoid colon stricture, and the patient was referred to our hospital with complaints of abdominal pain and fever. At 2-month postreferral, the patient presented with severe abdominal pain and fever. Computed tomography and intestinal ultrasonography revealed no bowel obstruction, whereas wall thickening was observed in the sigmoid colon and small bowel. Our medical interview revealed a cyclical nature to the symptoms. We diagnosed FMF and initiated colchicine. Subsequently, for more than 2 years, the patient remained asymptomatic, and the sigmoid colon stricture improved. FMF should be considered in patients with inflammatory bowel disease with periodic abdominal pain and fever.

Gout drives metabolic dysfunction-associated steatotic liver disease through gut microbiota and inflammatory mediators

This study explores the relationship between gout and metabolic dysfunction-associated steatotic liver disease (MASLD), two metabolic conditions linked to worsening health outcomes. While hyperuricemia's association with MASLD is established, the specific connection between gout and MASLD remains less explored. Using data from the UK Biobank, the study employs COX proportional hazard models, multi-state survival analysis, and Mendelian randomization to assess the independent and mutual risks of gout and MASLD. Findings indicate a mutual risk increase: male gout patients, those younger than 60, and those with high BMI are particularly susceptible to MASLD, while female MASLD patients are at heightened risk for gout. Shared risk factors for both conditions include high BMI, hypertension, diabetes, and hyperuricemia. The study further identifies a bidirectional causal link, with gout leading to MASLD, mediated by gut microbiota Ruminococcaceae and proteins like IL-2 and GDF11, implicating specific metabolic pathways. The findings highlight a clinical and mechanistic correlation, emphasizing the need for targeted interventions to address these overlapping metabolic pathways in future treatments.

Neutrophils and NETs in kidney disease

Neutrophils, conventionally regarded as a homogeneous immune cell population, have emerged as a heterogeneous group of cells with distinct gene profiles and immune properties. Activated neutrophils release a spectrum of bioactive substances, including cytokines, chemokines, proteolytic enzymes, reactive oxygen species and neutrophil extracellular traps (NETs), which are composed of decondensed DNA and antimicrobial proteins. NETs have a pivotal role in innate immunity, including in preventing the ascent of uropathogenic bacteria into the kidneys, as they efficiently trap pathogenic microorganisms. However, although indispensable for defence against pathogens, NETs also pose risks of self-damage owing to their cytotoxicity, thrombogenicity and autoantigenicity. Accordingly, neutrophils and NETs have been implicated in the pathogenesis of various disorders that affect the kidneys, including acute kidney injury, vasculitis, systemic lupus erythematosus, thrombotic microangiopathy and in various aetiologies of chronic kidney disease. Pathological alterations in the glomerular vascular wall can promote the infiltration of neutrophils, which can cause tissue damage and inflammation through their interactions with kidney-resident cells, including mesangial cells and podocytes, leading to local cell death. Targeting neutrophil activation and NET formation might therefore represent a new therapeutic strategy for these conditions.

TPL2 kinase activity is required for Il1b transcription during LPS priming but dispensable for NLRP3 inflammasome activation

The NLRP3 inflammasome complex is an important mechanism for regulating the release of pro-inflammatory cytokines, IL-1β and IL-18, in response to harmful pathogens. Overproduction of pro-inflammatory cytokines has been linked to cryopyrin-associated periodic syndrome, arthritis, and other inflammatory conditions. It has been previously shown that tumor progression locus 2, a serine-threonine kinase, promotes IL-1β synthesis in response to LPS stimulation; however, whether TPL2 kinase activity is required during inflammasome priming to promote Il1b mRNA transcription and/or during inflammasome activation for IL-1β secretion remained unknown. In addition, whether elevated type I interferons, a consequence of either Tpl2 genetic ablation or inhibition of TPL2 kinase activity, decreases IL-1β expression or inflammasome function has not been explored. Using LPS-stimulated primary murine bone marrow-derived macrophages, we determined that TPL2 kinase activity is required for transcription of Il1b, but not Nlrp3, Il18, caspase-1 (Casp1), or gasdermin-D (Gsdmd) during inflammasome priming. Both Casp1 and Gsdmd mRNA synthesis decreased in the absence of type I interferon signaling, evidence of crosstalk between type I interferons and the inflammasome. Our results demonstrate that TPL2 kinase activity is differentially required for the expression of inflammasome precursor cytokines and components but is dispensable for inflammasome activation. These data provide the foundation for the further exploration of TPL2 kinase inhibitor as a potential therapeutic in inflammatory diseases.

White Blood Cell Count Is Associated with Hyperuricemia in Patients with Type 2 Diabetes Mellitus

Background

Hyperuricemia is highly prevalent among patients with type 2 diabetes mellitus (T2DM). Inflammation is associated with the process of hyperuricemia. However, it is unclear whether white blood cell (WBC) count, a convenient inflammatory marker, is associated with hyperuricemia in patients with T2DM. Thus, we aimed to explore the possible association between WBC count and hyperuricemia in patients with T2DM.

Methods

A total of 1768 patients with T2DM were retrospectively included. Cumulative data were analyzed in patients with T2DM.

Results

WBC count was significantly elevated in T2DM patients with hyperuricemia compared with those without hyperuricemia (6.80 [5.60, 8.02] vs 6.20 [5.27, 7.24] 109/L, p<0.001). There was a significant positive correlation between WBC count and serum UA levels in patients with T2DM (r=0.165, 95% CI: [0.118, 0.211], p<0.001). Multivariable logistic regression analysis revealed an independent association between WBC count and hyperuricemia in patients with T2DM (OR=1.185, 95% CI: [1.077, 1.303], p<0.001).

Conclusion

Elevated WBC count, even within the normal range, is associated with hyperuricemia in patients with T2DM, suggesting that chronic inflammation, as indicated by a higher WBC count, may be related to the development of hyperuricemia in patients with T2DM and urate-lowering therapy may be helpful to ameliorate chronic inflammatory damage in T2DM patients with hyperuricemia.

Emerging Targets, Novel Directions, and Innovative Approaches in Thrombosis Therapy

In clinical practice, antiplatelet, anticoagulant and fibrinolytic drugs are the mainstay of thrombosis treatment, but their potential bleeding side effects limit their widespread use. Therefore, modifying these existing drugs or developing new therapies that mitigate bleeding risks while maintaining their efficacy and utilization is necessary. Since the critical role of platelets in thrombosis is closely related to their cell surface receptors, intracellular signaling pathways and metabolism, current research focuses on these three major classes of platelet targets to develop new antithrombotic drugs. The coagulation cascade has always been the main target of anticoagulant drugs, but since the role of molecules of the contact system is more critical in thrombosis than in hemostasis, molecules targeting the contact system, such as FXIa and FXIIa, have become the main direction of anticoagulant drug research at present. Moreover, since the inflammatory response has been found to be significantly associated with thrombosis in recent years, the development of drugs that target inflammatory pathways, such as inflammasome, has also become a hot topic. This article provides a detailed description of these targets or drug formulations that are currently being investigated, including their mode of action and antithrombotic efficiency, and also points out their existing shortcomings. Moreover, antithrombotic nanomedicines can achieve precise release of drugs, which can greatly improve the thrombolytic efficiency and reduce side effects. In conclusion, this review focuses on summarizing the current new targets and new methods of antithrombotic drug research, hoping to provide a little reference for future related research.

Discovery of DFV890, a Potent Sulfonimidamide-Containing NLRP3 Inflammasome Inhibitor

The discovery of DFV890 ((R)-1), a potent and selective NLRP3 antagonist, is described. Replacement of the sulfonyl urea core from the first-generation NLRP3 antagonist CRID3 with a sulfonimidamide core afforded a novel and potent series of NLRP3 antagonists. The (R)-enantiomers of the sulfonimidamide series were found to be consistently more potent than structurally related sulfonyl ureas. Replacement of the furan unit of CRID3 with a 5-substituted thiazole unit led to DFV890 ((R)-1), which potently inhibited IL-1β production in THP-1 cells and in primary human cells, blocked multiple downstream effectors of NLRP3 activation, and substantially improved PK properties and significantly lowered the predicted human dose compared to that for CRID3. DFV890 ((R)-1) was also effective in an air pouch model of gout.

Non-Anticoagulation Strategies Aimed at Primary Stroke Prevention in Nascent Atrial Fibrillation

At its earliest appearance, atrial fibrillation (AF) is often unnoticed, asymptomatic, and/or merely device-detected. Widespread use of heart-rate monitoring technologies has facilitated such "nascent atrial fibrillation (nAF)" recognition. Consequently, clinicians face a growing number of patients affected by new-onset AF in the absence of a definite indication for anticoagulation due to several counterarguments: (1) a CHA2DS2-VA score ≤ 1 in otherwise apparently healthy subjects; (2) an uncertain embolic/hemorrhagic benefit/risk ratio with anticoagulation; (3) EKG demonstration and confirmation of AF; and (4) existence of a pathogenic mechanism other than atrial hypercoagulability. In this frustrating limitation of pharmacological options, cardiologists may miss a complete comprehension of drugs with proven anti-ictal potential, whose administration may serve both as a bridge strategy toward future anticoagulation and as a consolidative strategy paralleling anticoagulation. This review aims to summarize and elucidate such therapeutic strategies and their preventative mechanisms.

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.

High-affinity uric acid clearance based on motile β-CD/F-127 polyrotaxane microspheres for enhanced diabetic wound repair

Hyperuricemia-related diabetic wounds are notoriously difficult to treat due to elevated uric acid (UA) levels, excessive reactive oxygen species (ROS), and chronic inflammation. Current therapies often fail to address these underlying causes, underscoring the need for innovative approaches that not only clear UA but also mitigate inflammation and promote tissue regeneration. In this study, we developed a polyrotaxane-based microsphere (HPR MS) system conjugated with 4,5-diamino-2-thiouracil (DT) to achieve high-affinity UA clearance without increasing cytotoxicity. By leveraging the molecular motility of the polyrotaxane structure, featuring β-cyclodextrin (β-CD) shuttles along the F-127 axis, we significantly improved the molecular recognition between DT and UA for enhanced UA absorption efficiency. In vitro experiments confirmed that HPR/DT MS rapidly reduced UA levels compared to control groups. Using a type 2 diabetic wound model, HPR/DT MS treatment effectively reduced UA levels, suppressed COX-2 expression, and transformed the immune microenvironment from a pro-inflammatory to a regenerative state in vivo. This was accompanied by enhanced M2 macrophage polarization, angiogenesis, and improved blood perfusion, resulting in accelerated wound healing. Overall, these findings highlight HPR/DT MS as a promising therapeutic strategy for hyperuricemia-related diabetic wounds, targeting the core pathological factors to improve wound repair.

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.

Post-hoc analysis of the CARES trial suggests delayed progression of chronic kidney disease in patients with gout during urate-lowering therapy

Based on the hypothesis that hyperuricemia is a modifiable risk factor for chronic kidney disease (CKD) progression, there is an expectation that urate-lowering therapy (ULT) could delay the progression of CKD. Here, we investigated changes in kidney function and the association of the serum uric acid (sUA) level and kidney function during ULT in patients with gout. To do this we conducted post-hoc analysis on patients who received ULT with either febuxostat or allopurinol for more than six months in the CARES trial. The estimated glomerular filtration rate (eGFR) slope (annual rate of change in eGFR) was calculated using the CKD-EPI creatinine equation and linear mixed modeling. Among the 5,002 patients with gout, 3,264 (65.3%) demonstrated an increased eGFR while receiving ULT over a median follow-up of 2.5 years. Increased average sUA levels were significantly associated with declines in eGFR slope (per 1 mg/dL increase, (adjusted beta of -0.1912). Propensity score matched analysis demonstrated a significant association between low average sUA levels below 6 mg/dL during ULT and a reduced risk of eGFR decline (adjusted odds ratio: 0.66, 95% confidence interval 0.57-0.77). Despite the well-documented natural decline of eGFR over time in the general population, more than half of the patients enrolled in the CARES trial did not experience declines in eGFR while receiving ULT. Thus, our study shows maintaining low sUA levels with ULT was significantly associated with a decreased risk of CKD progression in patients with gout.

Retained blood syndrome after cardiac surgery

OBJECTIVES

Retained blood syndrome (RBS) is defined as the postoperative retention of blood within the thoracic cavity. In addition to the mechanical impacts on cardiac and pulmonary function, RBS triggers inflammatory processes. It is associated with increased morbidity following cardiac surgery. The goal of this non-systematic review was to summarize the current understanding of the pathophysiology, consequences and both prophylactic and therapeutic measures related to RBS.

METHODS

The subjects to be covered were defined in advance. A literature search was conducted in PubMed and Google Scholar using relevant search terms and MeSH terms.

CONCLUSIONS

RBS is a significant complication following cardiac surgical procedures. It is associated with a poorer prognosis due to mechanical suppression of haemodynamics and the amplification of inflammatory processes. Therefore, preventing pericardial and pleural effusions should be a priority in cardiac surgical care. If RBS occurs, aggressive anti-inflammatory therapy should be initiated to prevent the development of long-term complications.

[Autoinflammatory diseases associated with IL-18]

Autoinflammatory diseases (AIDs) are conditions characterized by dysfunction of innate immunity, causing systemic inflammation and various clinical symptoms. The field of AIDs has expanded due to improved comprehension of pathophysiological mechanisms and advancements in genomics techniques. A new emerging category of AIDs is characterized by a significant increase in interleukin 18 (IL-18), a pro-inflammatory cytokine synthesized in macrophages and activated by caspase 1 via various inflammasomes. IL-18 plays a role in the regulation of innate and adaptive immunity. IL-18 is involved in various functions, such as the proliferation, survival, and differentiation of immune cells, tissue infiltration of immune cells, polarization of immune responses, and production of other pro-inflammatory cytokines. This review analyzes the literature on IL-18 regarding its functions and its implications in the diagnosis and treatment of AIDs. IL-18-associated AIDs comprise Still's disease and diseases associated with mutations in NLRC4, XIAP, CDC42, and PSTPIP1, as well as IL-18BP deficiencies. With the exception of PSTPIP1-associated diseases, these conditions all carry a risk of macrophagic activation syndrome. Measuring IL-18 levels in serum can aid in the diagnosis, prognosis, and monitoring of these diseases. Therapies targeting IL-18 and its signaling pathways are currently under investigation.

Roles of NLRC4 inflammasome in neurological disorders: Mechanisms, implications, and therapeutic potential

The nucleotide-binding oligomerization domain-like receptor family caspase recruitment domain containing 4 (NLRC4) inflammasome, a vital component of the innate immune system, is known for defending against bacterial infections. However, recent insights have revealed its significant impact on neurological disorders. This comprehensive review discussed the mechanisms underlying the activation and regulation of the NLRC4 inflammasome, highlighting the complexity of its response to cellular stress and damage signals. The biological functions of NLRC4 were explored, particularly its influence on cytokine production and the induction of pyroptosis, a form of inflammatory cell death. This review further emphasized the role of the NLRC4 inflammasome in brain injuries and neurodegenerative disorders. In the realm of brain injuries such as stroke and traumatic brain injury, as well as in neurodegenerative diseases including Alzheimer's disease, Parkinson's disease, multiple sclerosis, and amyotrophic lateral sclerosis, the NLRC4 inflammasome played a pivotal role in modulating neuroinflammatory responses, which was crucial for understanding the progression and potential therapeutic targeting of these conditions. The emerging role of NLRC4 in psychiatric disorders and its potential impact on glioma progression were also examined. Additionally, this review presented a thorough summary of the latest research on inhibitors that impeded the assembly and activation of the NLRC4 inflammasome, pointing to new therapeutic possibilities in neurological disorders. In conclusion, by integrating current knowledge on the activation and regulation of NLRC4 with its biological functions and clinical implications, this article underscored the importance of NLRC4 inflammasome in neurological pathologies, which opened new possibilities for the treatment of challenging neurological conditions.

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.

Developing Monosodium Urate Monohydrate Crystals-Induced Gout Model in Rodents and Rabbits

Gout is a chronic disease caused by the deposition of monosodium urate monohydrate (MSU) crystals within the body, particularly in one or more joints, which can lead to sudden severe attacks of pain, swelling, redness, and tenderness, known as gout flares. Historically termed the "disease of kings," gout is one of the oldest joint diseases and remains the most common form of inflammatory arthritis haunting humans in the 21st century. It is associated with cardiovascular, metabolic, and renal comorbidities and can lead to reduced mobility and impaired physical function and contributing to work absenteeism. Given its increasing global incidence, novel therapies for gouty arthritis disease are urgently needed. Experimental gout models are indispensable tools for deciphering disease pathogenesis and evaluating the efficacy and side effect of newly developed therapeutics at preclinical stage. Herein, we described a series of highly reproducible acute gout flare and air pouch models in rodents and rabbits that can be used to address various scientific questions relevant to pathological changes and immune responses during and after a gout attack. Animal gout flare models, elicited by MSU crystals, mimic the main histopathological features of human gouty arthritis, including damage to cartilage and joint swelling. Meanwhile, air pouch models serve as a tool to evaluate robust inflammatory cytokine secretion and neutrophil infiltration. This article provides a detailed description of procedures and troubleshooting tips required to reproducibly induce gout flare and air pouch models in animals and critically evaluate the pathogenesis of the disease. © 2025 Wiley Periodicals LLC. Basic Protocol 1: Preparation of monosodium urate crystalline Basic Protocol 2: Development of MSU-induced gout flare model in mice Support Protocol 1: Histological assessment of mouse ankle tissues Basic Protocol 3: Development of MSU-induced gout flare model in rats Basic Protocol 4: Development of MSU-induced gout flare model in rabbits Basic Protocol 5: Development and validation of reference articles in MSU-induced air pouch model in rats Basic Protocol 6: Development and validation of reference articles in MSU-induced air pouch model in mice Support Protocol 2: Flow cytometry of mouse neutrophils in air pouch lavage samples.

Cell death crosstalk in respiratory diseases: unveiling the relationship between pyroptosis and ferroptosis in asthma and COPD

Asthma and chronic obstructive pulmonary disease (COPD) are heterogeneous obstructive diseases characterized by airflow limitations and are recognized as significant contributors to fatality all over the globe. Asthma accounts for about 4, 55,000 deaths, and COPD is the 3rd leading contributor of mortality worldwide. The pathogenesis of these two obstructive disorders is complex and involves numerous mechanistic pathways, including inflammation-mediated and non-inflammation-mediated pathways. Among all the pathological categorizations, programmed cell deaths (PCDs) play a dominating role in the progression of these obstructive diseases. The two major PCDs that are involved in structural and functional remodeling in the progression of asthma and COPD are Pyroptosis and Ferroptosis. Pyroptosis is a PCD mechanism mediated by the activation of the Nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) inflammasome, leading to the maturation and release of Interleukin-1β and Interleukin-18, whereas ferroptosis is a lipid peroxidation-associated cell death. In this review, the major molecular pathways contributing to these multifaceted cell deaths have been discussed, and crosstalk among them regarding the pathogenesis of asthma and COPD has been highlighted. Further, the possible therapeutic approaches that can be utilized to mitigate both cell deaths at once have also been illustrated.

Multitargeted biological actions of polydatin in preventing pseudogout acute attack

Introduction

We have recently shown that polydatin (PD) prevents calcium pyrophosphate (CPP) crystal-induced arthritis in mice. This study aims to explore potential mechanisms of action associated with this anti-inflammatory effect.

Materials and methods

Acute arthritis was induced in Balb/c mice by the injection of crystals into the ankle joint. Animals were randomised to receive PD or colchicine according to a prophylactic protocol. Ankle swelling was measured and both joints and muscles were harvested at sacrifice. Histological evaluations were performed using H&E staining to assess cartilage and muscle damage. Kondziela's inverted test was used to assess muscle strength. An exploratory protein array was performed on joint tissue to identify relevant inflammatory pathways. Human monocytes pretreated with PD were stimulated with CPP crystals. The use of specific inhibitors was instrumental in demonstrating their anti-inflammatory effects and assessing the role of SIRT1. The chemotaxis assay was performed to test the effect of PD and J-113863 on PBMCs migration in response to plasma and synovial fluids. Cytokine levels were measured by ELISA.

Results

CPP crystals injection resulted in swelling, leukocyte infiltration, loss of synovial membrane structure homogeneity. Mice pretreated with PD showed reduced ankle swelling and this was associated with very limited inflammatory damage. Regarding the effect on gastrocnemius muscle, crystals induced leukocyte infiltration and edema. PD and colchicine treatment reduced muscle damage and preserved musculoskeletal structure in mice. The cytokine array revealed the activation of various inflammatory pathways after CPP injection and PD was shown to influence leukocyte migration, angiogenesis and inflammation. In vitro, PD reduced inflammatory cytokines, chemokines and VEGF levels. CCR-1 inhibition was effective in reducing pro-inflammatory mediator levels in CPP treated monocytes and in reducing PBMCs migration. The anti-inflammatory action of PD also involved SIRT-1 activation, and its inhibition reverted the beneficial effects of PD. Finally, PD reduced the PBMCs migration in response to synovial fluids.

Conclusion

PD effectively prevents inflammatory responses to CPP crystals in mice, preserving both articular and muscular structures. Its anti-inflammatory effects are primarily mediated through pathways regulating leukocyte migration and the suppression of pro-inflammatory mediators.

Discovery of Potent and Brain-Penetrant Bicyclic NLRP3 Inhibitors with Peripheral and Central In Vivo Activity

NLRP3 is a danger sensor protein responsible for inflammasome activation. This leads to pro-inflammatory cytokines release, like IL-1β, and pyroptosis, a regulated cell death. Mounting evidence associates excessive NLRP3 activation to neurodegenerative conditions, such as Alzheimer's and Parkinson's diseases. Thus, NLRP3 inhibitors could potentially provide therapeutic benefit for these disorders. We describe here the evolution of inhibitors relying on a pyridazine-based motif for their key interactions with NLRP3. A Cryo-EM structure helped optimizing protein-ligand complementarity. Subsequently, conformational NMR studies pointed the efforts toward 5,6-bicyclic cores that allowed a balance between brain penetration and undesirable properties, such as hERG inhibition. The effort culminated in compound 19, which showed moderate (mouse) to good (rat) brain penetration and was active at low dose in an LPS challenge model. Importantly, an earlier compound was active in a central neuroinflammation model providing a valuable proof of concept for NLRP3 inhibition.

NLRP3 inflammasome in cardiovascular diseases: an update

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

Cornuside alleviates cognitive impairments induced by Aβ1-42 through attenuating NLRP3-mediated neurotoxicity by promoting mitophagy

Alzheimer's disease (AD) is a progressive neurodegenerative disorder in which mitochondrial dysfunction and neuroinflammation play crucial roles in its progression. Our previous studies found that cornuside from Cornus officinalis Sieb.Et Zucc is an anti-AD candidate, however, its underlying mechanism remains unknown. In the present study, AD mice were established by intracerebroventricular injection of Aβ1-42 and treated with cornuside (3, 10, 30 mg/kg) for 2 weeks. Cornuside significantly ameliorated behavioral deficits, protected synaptic plasticity and relieved neuronal damage in Aβ1-42 induced mice. Importantly, cornuside decreased NLRP3 inflammasome activation, characterized by decreased levels of NLRP3, ASC, Caspase-1, GSDMD, and IL-1β. Furthermore, cornuside promoted mitophagy accompanied by decreasing SQSTM1/p62 and promoting LC3B-I transforming into LC3B-II, via Pink1/Parkin signaling instead of FUNDC1 or BNIP3 pathways. In order to investigate the relationship between NLRP3 inflammasome and mitophagy in the neuroprotective mechanism of cornuside, we established an in-vitro model in BV2 cells exposed to LPS and Aβ1-42. And cornuside inhibited NLRP3 inflammasome activation and subsequent cytokine release, also protected neurons from damaging factors in microenvironment of conditional culture. Cornuside improved mitochondrial function by promoting oxidative phosphorylation and glycolysis, decreasing the production of ROS and mitochondrial membrane potential depolarization. Besides, mitophagy was also facilitated with increased colocalization of MitoTracker with LC3B and Parkin, and Pink1/Parkin, FUNDC1 and BNIP3 pathways were all involved in the mechanism of cornuside. By blocking the formation of autophagosomes by 3-MA, the protective effects on mitochondria, the inhibition on NLRP3 inflammasome as well as neuronal protection in conditional culture were eliminated. There is reason to believe that the promotion of mitophagy plays a key role in the NLRP3 inhibition of cornuside. In conclusion, cornuside re-establishes the mitophagy flux which eliminates damaged mitochondria and recovers mitochondrial function, both of them are in favor of inhibiting NLRP3 inflammasome activation, then alleviating neuronal and synaptic damage, and finally improving cognitive function.

J-Shaped Association Between Non-HDL Cholesterol to HDL Cholesterol Ratios and Gout in US Adults With Gout

Background and Aim

This study aims to assess the potential association between NHHR and gout risk among the US adult population.

Methods and Results

Utilizing data from the NHANES spanning from 2007 to 2018, we performed a cross-sectional analysis. A weighted multivariable logistic regression model, generalized additive model (GAM) and a restricted cubic spline model were applied to elucidate the association between NHHR and gout risk. In addition, subgroup and sensitivity analyses were conducted to ensure the stability of our findings. This study cohort included 27,731 participants. Multivariate logistic regression analysis indicated a significant correlation between NHHR and the likelihood of gout. This association was sustained after accounting for a range of potential confounding confounders. The risk of gout was observed to escalate with increasing quartiles of NHHR quartiles, with a 67% increased risk in the fourth quartile. Both RCS and curve fitting results indicated a J-shaped relationship between NHHR and gout. The association remained significant in several subgroup analyses. The interaction test did not yield statistically significant effects on this association.

Conclusion

The NHHR is nonlinearly correlated with the risk of gout in US adults. Further investigation research into the role of NHHR in gout could offer new perspectives on the prevention and treatment of gout. However, additional large-scale prospective studies are necessary to validate and reinforce these results.

The role of hyperuricemia in the progression of end-stage kidney disease and its molecular prospective in inflammation and cardiovascular diseases: A general review

With the ongoing development of the Chinese economy, the occurrence of chronic kidney disease (CKD) has experienced a remarkable upsurge recently, and due to uremia caused by CKD, the number of patients undergoing dialysis has shown a dramatic increase. China has been ranked first in the world for patients undergoing hemodialysis (HD) and peritoneal dialysis (PD) with approximately one million patients across the country. Due to the loss of kidney function caused by CKD, the kidneys tend to lose their ability to excrete uric acid (UA) out of the body; therefore, most patients undergoing dialysis are complicated with hyperuricemia (HUA). HUA is an abnormal disease of purine metabolism, and it's considered a chronic disease. More than 90% of patients suffering from HUA will not show any symptoms on physical examination. According to statistics, if high serum UA is left untreated, 55% of patients will develop severe problems due to the purine crystallization in the body, and the kidneys are the most affected organs by HUA causing renal insufficiency that can promote end-stage kidney disease (ESKD) by activating the renin-angiotensin system (RAS), which will lead to inflammation, arteriosclerosis, cardiovascular diseases (CVD), and other diseases. Lifestyle modifications and pharmacological interventions are the first primary choice for lowering UA, although dialysis will tend to reduce the high UA levels in the blood, drugs are also necessary. This review will summarize the mechanisms and metabolism of UA, the relationship between HUA and ESKD progression, HUA and inflammation, HUA and CVD, and pharmacological treatment of HUA.

Arginine-Rich Peptides Regulate the Pathogenic Galectin-10 Crystallization and Mitigate Crystallopathy-Associated Inflammation

Protein self-assembly into a crystal in vivo triggers acute or chronic organ injury that can lead to intractable diseases lacking specific treatment options. In this study, we report the discovery of ionic arginine-rich peptides to disrupt the pathogenic galectin-10 (gal-10) crystallization, where the aberrant deposition of gal-10 crystals in airways causes the activation of IL-1β-dependent inflammation and the stimulation of epithelial cells to produce TNF-α. Gal-10 crystals show susceptibility to pH changes and charged residue substitutions at the protein packing interfaces, manifesting the role of charge-charge attractions across protein-protein interaction interfaces in governing gal-10 crystallization. To dissolve the gal-10 crystal, the ionic peptides R9 and R12Y8 were identified to eliminate the interprotein charge-charge interactions. The efficacy of R12Y8 in mitigating the gal-10 crystallopathy in vivo was assessed in a crystal-induced lung inflammation mice model. The mice intratracheally administrated by R12Y8 exhibited a downregulated release of proinflammatory cytokines and reduced infiltration of inflammatory cells in the lungs. Our study demonstrates that the pathogenic gal-10 crystallization is readily eliminated by R-rich peptides, which may display translational potentials for the treatment of gal-10 crystallopathy.

The Role of Purine Metabolism and Uric Acid in Postnatal Neurologic Development

This review explores the essential roles of purine metabolism including the catabolic product, uric acid, in the development of dopaminergic neurons of the substantia nigra pars compacta. The high energy requirements of the substantia nigra pars compacta alongside necessary purinergic neurotransmission and the influence of oxidative stress during development makes these neurons uniquely susceptible to changes in purine metabolism. Uric acid's role as a central nervous system antioxidant may help to ameliorate these effects in utero. Understanding the mechanisms by which purines and uric acid influence development of the substantia nigra pars compacta can help further explain neurologic consequences of inborn errors of purine metabolism, such as Lesch-Nyhan disease.