Natural Products as a Novel Therapeutic Strategy for NLRP3 Inflammasome-Mediated Gout

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.

Zanthoxylum piperitum Benn. Attenuates Monosodium Urate-Induced Gouty Arthritis: A Network Pharmacology Investigation of Its Anti-Inflammatory Mechanisms

Background: Monosodium urate crystal accumulation in the joints is the cause of gout, an inflammatory arthritis that is initiated by elevated serum uric acid levels. It is the most prevalent form of inflammatory arthritis, affecting millions worldwide, and requires effective treatments. The necessity for alternatives with fewer side effects is underscored by the frequent adverse effects of conventional therapies, such as urate-lowering drugs. IL-1β is a potential therapeutic target due to its significant role in the inflammatory response induced by MSU. Zanthoxylum piperitum Benn. (ZP), a shrub that possesses antibacterial, antioxidant, and anti-inflammatory properties, has demonstrated potential in the treatment of inflammatory conditions. Methods: For anti-inflammatory properties of ZP, Raw264.7 cell stimulated LPS were treated ZP and using RNA-seq with Bone marrow derived macrophage, we observed to change inflammatory gene. Pharmacological networks were conducted to select target gene associated with ZP. For in vivo, mice were injected MSU in footpad for induce gouty arthritis model. The components of ZP were analyzed using GC-MS, and distilled extracts of ZP (deZP) were prepared. Results: In vitro, deZP decreased inflammatory cytokines. However, in vivo, it also decreased paw thickness and IL-1β levels. The anti-inflammatory effects of deZP are believed to be mediated through the NLRP3 inflammasome pathway, as indicated by RNA sequencing and network pharmacology analyses. Conclusions: ZP has an anti-inflammatory effect and regulation of the NLRP3 inflammasome in vitro and in vivo. Further research, including clinical trials, is required to confirm the safety of deZP, determine the optimal dosing, and evaluate its long-term effects.

Role of HIF1A gene polymorphisms with serum uric acid and HIF-1α levels in monosodium urate crystal-induced arthritis

BACKGROUND

Gouty arthritis is a metabolic disease characterized by the deposition of monosodium urate crystals in the joints, which triggers the release of interleukin-1β (IL-β) by activating the NLRP3 inflammasome. Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor involved in IL-β production and as a regulator of NLRP3.

OBJECTIVES

The aims were to analyze the association of HIF1A rs11549465, rs11549467, and rs2057482 variants in patients with gouty arthritis, and to evaluate the correlation between urate and HIF-1α levels according to the associated genotypes.

METHODS

Cases and controls were genotyped using TaqMan probes, and urate and HIF-1α levels were quantified. Data were analyzed using SPSS v21 software and P-values < 0.05 were considered statistically significant.

RESULTS

Urate and HIF-1α levels were higher in patients than in controls (P < 0.05). Under the three inheritance models (codominant, dominant, and recessive), the AA genotype of the rs11549467 variant was associated with gout risk (OR = 5.74, P = 0.009, OR = 3.33, P = 0.024, and OR = 9.09, P = 0.003, respectively). There were significant differences in the distribution of serum levels of both HIF-1α (P < 0.0001) and urate (P = 0.016) according to the genotypes of the rs11549467 variant.

CONCLUSION

These results suggest that the HIF1A rs11549467 variant may play a key role in the pathogenesis of gouty arthritis. Key Points • The pathogenesis of gouty arthritis involves the HIF1A gene. • In patients with gout, the AA genotype of the rs11549467 (HIF1A) variant is associated with increased serum levels of urate and HIF-1α. • HIF-1α is involved in the regulation of IL-1β and NLRP3.

Gut microecology: effective targets for natural products to modulate uric acid metabolism

Gut microecology,the complex community consisting of microorganisms and their microenvironments in the gastrointestinal tract, plays a vital role in maintaining overall health and regulating various physiological and pathological processes. Recent studies have highlighted the significant impact of gut microecology on the regulation of uric acid metabolism. Natural products, including monomers, extracts, and traditional Chinese medicine formulations derived from natural sources such as plants, animals, and microorganisms, have also been investigated for their potential role in modulating uric acid metabolism. According to research, The stability of gut microecology is a crucial link for natural products to maintain healthy uric acid metabolism and reduce hyperuricemia-related diseases. Herein, we review the recent advanced evidence revealing the bidirectional regulation between gut microecology and uric acid metabolism. And separately summarize the key evidence of natural extracts and herbal formulations in regulating both aspects. In addition,we elucidated the important mechanisms of natural products in regulating uric acid metabolism and secondary diseases through gut microecology, especially by modulating the composition of gut microbiota, gut mucosal barrier, inflammatory response, purine catalyzation, and associated transporters. This review may offer a novel insight into uric acid and its associated disorders management and highlight a perspective for exploring its potential therapeutic drugs from natural products.

Hyperuricemia and its related diseases: mechanisms and advances in therapy

Hyperuricemia, characterized by elevated levels of serum uric acid (SUA), is linked to a spectrum of commodities such as gout, cardiovascular diseases, renal disorders, metabolic syndrome, and diabetes, etc. Significantly impairing the quality of life for those affected, the prevalence of hyperuricemia is an upward trend globally, especially in most developed countries. UA possesses a multifaceted role, such as antioxidant, pro-oxidative, pro-inflammatory, nitric oxide modulating, anti-aging, and immune effects, which are significant in both physiological and pathological contexts. The equilibrium of circulating urate levels hinges on the interplay between production and excretion, a delicate balance orchestrated by urate transporter functions across various epithelial tissues and cell types. While existing research has identified hyperuricemia involvement in numerous biological processes and signaling pathways, the precise mechanisms connecting elevated UA levels to disease etiology remain to be fully elucidated. In addition, the influence of genetic susceptibilities and environmental determinants on hyperuricemia calls for a detailed and nuanced examination. This review compiles data from global epidemiological studies and clinical practices, exploring the physiological processes and the genetic foundations of urate transporters in depth. Furthermore, we uncover the complex mechanisms by which the UA induced inflammation influences metabolic processes in individuals with hyperuricemia and the association with its relative disease, offering a foundation for innovative therapeutic approaches and advanced pharmacological strategies.

Mechanism of Reactive Oxygen Species-Guided Immune Responses in Gouty Arthritis and Potential Therapeutic Targets

Gouty arthritis (GA) is an inflammatory disease caused by monosodium urate (MSU) crystals deposited in the joint tissues causing severe pain. The disease can recur frequently and tends to form tophus in the joints. Current therapeutic drugs for the acute phase of GA have many side effects and limitations, are unable to prevent recurrent GA attacks and tophus formation, and overall efficacy is unsatisfactory. Therefore, we need to advance research on the microscopic mechanism of GA and seek safer and more effective drugs through relevant targets to block the GA disease process. Current research shows that the pathogenesis of GA is closely related to NLRP3 inflammation, oxidative stress, MAPK, NET, autophagy, and Ferroptosis. However, after synthesizing and sorting out the above mechanisms, it is found that the presence of ROS is throughout almost the entire spectrum of micro-mechanisms of the gout disease process, which combines multiple immune responses to form a large network diagram of complex and tight connections involved in the GA disease process. Current studies have shown that inflammation, oxidative stress, cell necrosis, and pathological signs of GA in GA joint tissues can be effectively suppressed by modulating ROS network-related targets. In this article, on the one hand, we investigated the generative mechanism of ROS network generation and its association with GA. On the other hand, we explored the potential of related targets for the treatment of gout and the prevention of tophus formation, which can provide effective reference ideas for the development of highly effective drugs for the treatment of GA.

The alleviatory effects of koumine on MSU-induced gouty arthritis via the TLR4/NF-κB/NLRP3 pathway

The aim of this study was to validate the preventive effects of koumine (KM), a monoterpene indole alkaloid, on gouty arthritis (GA) and to explore its possible mechanisms. C57BL/6 mice were intraperitoneally administered KM (0.8, 2.4 or 7.2 mg/kg), colchicine (3.0 mg/kg) or sterile saline. One hour later, a monosodium urate (MSU) suspension was injected into the right hind paws of the mice to establish an acute gout model. Inflammation symptoms were evaluated at 0, 3, 6, 12 and 24 h, and the mechanical withdrawal threshold was evaluated at 0, 6 and 24 h. After 24 h, the mice were euthanized, and the joint tissue, kidney and blood were collected for subsequent experiments. Histological examination and antioxidant enzyme, kidney index and serum uric acid (UA) measurements were taken. The expression levels of the signalling pathway components were determined. KM effectively alleviated the symptoms of redness, swelling and pain; counteracted inflammatory cell infiltration; and increased antioxidant enzyme levels, reduced kidney index and serum UA levels through regulating UA excretion in MSU-induced mice. The expression of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB)/nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 (NLRP3) signalling pathway proteins and mRNA were reduced in the KM group. These results suggest that KM may be effective in alleviating GA through the TLR4/NF-κB/NLRP3 pathway.

Molecular Foundations of Inflammatory Diseases: Insights into Inflammation and Inflammasomes

Inflammatory diseases are a global health problem affecting millions of people with a wide range of conditions. These diseases, including inflammatory bowel disease (IBD), rheumatoid arthritis (RA), osteoarthritis (OA), gout, and diabetes, impose a significant burden on patients and healthcare systems. A complicated interaction between genetic variables, environmental stimuli, and dysregulated immune responses shows the complex biological foundation of various diseases. This review focuses on the molecular mechanisms underlying inflammatory diseases, including the function of inflammasomes and inflammation. We investigate the impact of environmental and genetic factors on the progression of inflammatory diseases, explore the connection between inflammation and inflammasome activation, and examine the incidence of various inflammatory diseases in relation to inflammasomes.

Targeting the NLRP3 inflammasome for the treatment of hypertensive target organ damage: Role of natural products and formulations

BACKGROUND AND AIM

Hypertension is a major global health problem that causes target organ damage (TOD) in the heart, brain, kidney, and blood vessels. The mechanisms of hypertensive TOD are not fully understood, and its treatment is challenging. This review provides an overview of the current knowledge on the role of Nod-like receptor pyrin domain containing 3 (NLRP3) inflammasome in hypertensive TOD and the natural products and formulations that inhibit it.

METHODS

We searched PubMed, Web of Science, Google Scholar, and CNKI for relevant articles using the keywords "hypertension," "target organ damage," "NLRP3 inflammasome," "natural products," and "formulations." We reviewed the effects of the NLRP3 inflammasome on hypertensive TOD in different organs and discussed the natural products and formulations that modulate it.

KEY RESULTS

In hypertensive TOD, the NLRP3 inflammasome is activated by various stimuli such as oxidative stress and inflammation. Activation of NLRP3 inflammasome leads to the production of pro-inflammatory cytokines that exacerbate tissue damage and dysfunction. Natural products and formulations, including curcumin, resveratrol, triptolide, and allicin, have shown protective effects against hypertensive TOD by inhibiting the NLRP3 inflammasome.

CONCLUSIONS AND IMPLICATIONS

The NLRP3 inflammasome is a promising therapeutic target in hypertensive TOD. Natural products and formulations that inhibit the NLRP3 inflammasome may provide novel drug candidates or therapies for hypertensive TOD. Further studies are needed to elucidate the molecular mechanisms and optimize the dosages of these natural products and formulations and evaluate their clinical efficacy and safety.

Potential roles of NLRP3 inflammasome in the pathogenesis of Kawasaki disease

There is a heterogeneous group of rare illnesses that fall into the vasculitis category and are characterized mostly by blood vessel inflammation. Ischemia and disrupted blood flow will cause harm to the organs whose blood arteries become inflamed. Kawasaki disease (KD) is the most prevalent kind of vasculitis in children aged 5 years or younger. Because KD's cardiovascular problems might persist into adulthood, it is no longer thought of as a self-limiting disease. KD is a systemic vasculitis with unknown initiating factors. Numerous factors, such as genetic predisposition and infectious pathogens, are implicated in the etiology of KD. As endothelial cell damage and inflammation can lead to coronary endothelial dysfunction in KD, some studies hypothesized the crucial role of pyroptosis in the pathogenesis of KD. Additionally, pyroptosis-related proteins like caspase-1, apoptosis-associated speck-like protein containing a CARD (ASC), proinflammatory cytokines like IL-1 and IL-18, lactic dehydrogenase, and Gasdermin D (GSDMD) have been found to be overexpressed in KD patients when compared to healthy controls. These occurrences may point to an involvement of inflammasomes and pyroptotic cell death in the etiology of KD and suggest potential treatment targets. Based on these shreds of evidence, in this review, we aim to focus on one of the well-defined inflammasomes, NLRP3, and its role in the pathophysiology of KD.