The ethanolic extract of Artemisia anomala exerts anti-inflammatory effects via inhibition of NLRP3 inflammasome

Novel Isoalantolactone-Based Derivatives as Potent NLRP3 Inflammasome Inhibitors: Design, Synthesis, and Biological Characterization

The NLRP3 inflammasome has been recognized as a promising therapeutic target in drug discovery for inflammatory diseases. Our initial research identified a natural sesquiterpene isoalantolactone (IAL) as the active scaffold targeting NLRP3 inflammasome. To improve its activity and metabolic stability, a total of 64 IAL derivatives were designed and synthesized. Among them, compound 49 emerged as the optimal lead, displaying the most potent inhibitory efficacy on nigericin-induced IL-1β release in THP-1 cells, with an IC50 value of 0.29 μM, approximately 27-fold more potent than that of IAL (IC50: 7.86 μM), and exhibiting higher metabolic stability. Importantly, 49 remarkably improved DSS-induced ulcerative colitis in vivo. Mechanistically, we demonstrated that 49 covalently bound to cysteine 279 in the NACHT domain of NLRP3, thereby inhibiting the assembly and activation of NLRP3 inflammasome. These results provided compelling evidence to further advance the development of more potent NLRP3 inhibitors based on this scaffold.

Shen-Ling-Bai-Zhu-San alleviates the imbalance of intestinal homeostasis in dextran sodium sulfate-induced colitis mice by regulating gut microbiota and inhibiting the NLRP3 inflammasome activation

ETHNOPHARMACOLOGICAL RELEVANCE

Shen-Ling-Bai-Zhu-San (SLBZS) is a classic formula for strengthening the spleen and dispelling dampness, which has shown excellent efficacy in inflammatory bowel disease (IBD) in traditional Chinese medicine clinical studies. However, its exact pharmacological mechanism needs to be further elucidated.

AIM OF THE STUDY

This study aims to investigate the restorative effect and mechanism of SLBZS on disturbed intestinal homeostasis in DSS-induced colitis mice.

MATERIALS AND METHODS

A colitis model was induced by 3% dextran sulfate sodium (DSS) for seven days, and SLBZS was administered by gavage. The influence of SLBZS on DSS-induced clinical symptoms and disease activity index (DAI) was monitored and analyzed. Alcian blue and fluorescein isothiocyanate-conjugated wheat germ agglutinin (FITC-WGA) staining were used to assess intestinal mucus changes. The expression of intestinal barrier function indexes and immune-associated indexes were determined by H&E staining, real-time quantitative PCR (RT-qPCR), and Western blot. And gut microbiota changes were detected by 16S rDNA sequencing technology. The antibiotic experiment was used to explore the role of gut microbiota in SLBZS treatment.

RESULTS

The results showed that SLBZS significantly improved the physiological indexes including body weight, DAI score, and colon length of colitis mice. We focused on the effects of SLBZS on intestinal homeostasis in colitis mice. First, SLBZS could enhance the secretion of intestinal mucin and the expression levels of tight junctions and adhesive junctions. Second, SLBZS inhibited the expression level of inflammatory factors and reduced the protein expression level of NLRP3 inflammasome. Third, 16S rDNA sequencing analysis revealed that SLBZS repaired the dysfunctional gut microbiota of colitis mice, such as enhancing the abundance of short-chain fatty acid-producing bacteria including Faecalibaculum, Colidextribacter, and Coprococcus. Further, by gut microbiota-depleted mice, we found that SLBZS could not exert an anti-colitis effect when gut microbiota was absent.

CONCLUSIONS

SLBZS restored intestinal environmental homeostasis by enhancing intestinal barrier function, inhibiting NLRP3 inflammasome, and restoring disturbed gut microbiota. And SLBZS could not ameliorate colitis mice with depleted gut microbiota. Our finding provided a theoretical basis for the clinical application of SLBZS in IBD.

Medicinal Plants, Phytochemicals and Regulation of the NLRP3 Inflammasome in Inflammatory Bowel Diseases: A Comprehensive Review

Ongoing research explores the underlying causes of ulcerative colitis and Crohn's disease. Many experts suggest that dysbiosis in the gut microbiota and genetic, immunological, and environmental factors play significant roles. The term "microbiota" pertains to the collective community of microorganisms, including bacteria, viruses, and fungi, that reside within the gastrointestinal tract, with a particular emphasis on the colon. When there is an imbalance or disruption in the composition of the gut microbiota, it is referred to as dysbiosis. Dysbiosis can trigger inflammation in the intestinal cells and disrupt the innate immune system, leading to oxidative stress, redox signaling, electrophilic stress, and inflammation. The Nod-like Receptor (NLR) Family Pyrin Domain Containing 3 (NLRP3) inflammasome, a key regulator found in immunological and epithelial cells, is crucial in inducing inflammatory diseases, promoting immune responses to the gut microbiota, and regulating the integrity of the intestinal epithelium. Its downstream effectors include caspase-1 and interleukin (IL)-1β. The present study investigated the therapeutic potential of 13 medicinal plants, such as Litsea cubeba, Artemisia anomala, Piper nigrum, Morus macroura, and Agrimonia pilosa, and 29 phytocompounds such as artemisitene, morroniside, protopine, ferulic acid, quercetin, picroside II, and hydroxytyrosol on in vitro and in vivo models of inflammatory bowel diseases (IBD), with a focus on their effects on the NLRP3 inflammasome. The observed effects of these treatments included reductions in IL-1β, tumor necrosis factor-alpha, IL-6, interferon-gamma, and caspase levels, and increased expression of antioxidant enzymes, IL-4, and IL-10, as well as regulation of gut microbiota. These effects could potentially provide substantial advantages in treating IBD with few or no adverse effects as caused by synthetic anti-inflammatory and immunomodulated drugs. However, additional research is necessary to validate these findings clinically and to develop effective treatments that can benefit individuals who suffer from these diseases.

The protection of luteolin against diabetic cardiomyopathy in rats is related to reversing JNK-suppressed autophagy

Increasing evidence has shown that impaired autophagy dramatically causes myocardial hypertrophy and fibrosis in the diabetic heart, ultimately leading to diabetic cardiomyopathy (DCM). Luteolin has been reported to effectively attenuate diabetic cardiovascular injury by inhibiting oxidative stress and alleviate sepsis-induced myocardial injury by enhancing autophagy. However, whether luteolin can reduce DCM through activating autophagy and the underlying mechanism remain unclear. Here, reversing the c-Jun N-terminal kinase (JNK)-suppressed autophagy pathway by which luteolin attenuates DCM was explored. Male Sprague-Dawley rats were injected with streptozotocin to induce diabetes. After 6 weeks of diabetes, rats were treated with luteolin (50, 100 and 200 mg kg^-1, i.g.) for 4 weeks. Histological and functional alterations in the diabetic heart were determined using HE staining, Masson staining and echocardiography. The expressions of myocardial miR-221, JNK, and c-Jun and autophagic vesicles in diabetes were evaluated by quantitative PCR, Western blotting and electron microscopy. Luteolin significantly improved cardiac function and attenuated myocardial disorganization and fibrosis in the diabetic rat accompanying the dose-dependent down-regulation of JNK, c-Jun, miR-221 and p62, increase of LC3-II/I and autophagic vesicles, and decrease of mitochondrial swelling in the diabetic heart. These data suggest that the protection of luteolin against DCM, at least, is related to suppressing JNK/c-Jun-regulated miR-221 and the subsequent blockage of autophagy.

Protective effecs of baicalin magnesium on non-alcoholic steatohepatitis rats are based on inhibiting NLRP3/Caspase-1/IL-1β signaling pathway

Baicalin magnesium is a water-soluble compound isolated from the aqueous solution by Scutellaria baicalensis Georgi. Preliminary experiments have demonstrated that baicalin magnesium can exert protective effects against acute liver injury in rats induced by carbon tetrachloride or lipopolysaccharide combined with d-galactose by regulating lipid peroxidation and oxidative stress. The aim of this study was to investigate the protective effect of baicalin magnesium on non-alcoholic steatohepatitis (NASH) in rats and to elucidate the underlying mechanisms. NASH was induced through a high-fat diet (HFD) for 8 weeks, and Sprague-Dawley rats were intravenously injected with baicalin magnesium, baicalin, and magnesium sulfate for 2 weeks, respectively. Serum was obtained for biochemical analyses and the determination of oxidative stress indicators. Liver tissues were collected for use in liver index assessment, histopathological examination, inflammatory factor analysis, and protein and gene expression analysis. The results revealed that baicalin magnesium markedly improved HFD-induced lipid deposition, inflammatory response, oxidative stress, and histopathological impairments. And baicalin magnesium may exert a protective effect on NASH rats by inhibiting the NLR family pyrin domain involving the 3 (NLRP3)/caspase-1/interleukin (IL)-1β inflammatory pathway. Additionally, the effect of baicalin magnesium was remarkably superior to that of equimolar baicalin and magnesium sulfate in regard to ameliorating NASH symptoms. In conclusion, the findings suggested that baicalin magnesium may represent a potential drug for the treatment of NASH.

Steroidal alkaloid with unprecedented triheterocyclic architecture

Veratrazine A (1), a steroidal alkaloid with a unique 6/5/5 triheterocyclic scaffold as the side chain, was isolated from Veratrum stenophyllum, and its structure was established via spectroscopic analyses and X-ray diffraction. A plausible biosynthetic pathway for 1 is proposed. Bioassy exhibits moderate anti-inflammatory activities in vitro and in vivo.

Uncoupled pyroptosis and IL-1β secretion downstream of inflammasome signaling

Inflammasomes are supramolecular platforms that organize in response to various damage-associated molecular patterns and pathogen-associated molecular patterns. Upon activation, inflammasome sensors (with or without the help of ASC) activate caspase-1 and other inflammatory caspases that cleave gasdermin D and pro-IL-1β/pro-IL-18, leading to pyroptosis and mature cytokine secretion. Pyroptosis enables intracellular pathogen niche disruption and intracellular content release at the cost of cell death, inducing pro-inflammatory responses in the neighboring cells. IL-1β is a potent pro-inflammatory regulator for neutrophil recruitment, macrophage activation, and T-cell expansion. Thus, pyroptosis and cytokine secretion are the two main mechanisms that occur downstream of inflammasome signaling; they maintain homeostasis, drive the innate immune response, and shape adaptive immunity. This review aims to discuss the possible mechanisms, timing, consequences, and significance of the two uncoupling preferences downstream of inflammasome signaling. While pyroptosis and cytokine secretion may be usually coupled, pyroptosis-predominant and cytokine-predominant uncoupling are also observed in a stimulus-, cell type-, or context-dependent manner, contributing to the pathogenesis and development of numerous pathological conditions such as cryopyrin-associated periodic syndromes, LPS-induced sepsis, and Salmonella enterica serovar Typhimurium infection. Hyperactive cells consistently release IL-1β without LDH leakage and pyroptotic death, thereby leading to prolonged inflammation, expanding the lifespans of pyroptosis-resistant neutrophils, and hyperactivating stimuli-challenged macrophages, dendritic cells, monocytes, and specific nonimmune cells. Death inflammasome activation also induces GSDMD-mediated pyroptosis with no IL-1β secretion, which may increase lethality in vivo. The sublytic GSDMD pore formation associated with lower expressions of pyroptotic components, GSDMD-mediated extracellular vesicles, or other GSDMD-independent pathways that involve unconventional secretion could contribute to the cytokine-predominant uncoupling; the regulation of caspase-1 dynamics, which may generate various active species with different activities in terms of GSDMD or pro-IL-1β, could lead to pyroptosis-predominant uncoupling. These uncoupling preferences enable precise reactions to different stimuli of different intensities under specific conditions at the single-cell level, promoting cooperative cell and host fate decisions and participating in the pathogen "game". Appropriate decisions in terms of coupling and uncoupling are required to heal tissues and eliminate threats, and further studies exploring the inflammasome tilt toward pyroptosis or cytokine secretion may be helpful.

Comparative and phylogenetic analysis of complete chloroplast genomes from five Artemisia species

Artemisia Linn. is a large genus within the family Asteraceae that includes several important medicinal plants. Because of their similar morphology and chemical composition, traditional identification methods often fail to distinguish them. Therefore, developing an effective identification method for Artemisia species is an urgent requirement. In this study, we analyzed 15 chloroplast (cp) genomes, including 12 newly sequenced genomes, from 5 Artemisia species. The cp genomes from the five Artemisia species had a typical quadripartite structure and were highly conserved across species. They had varying lengths of 151,132-151,178 bp, and their gene content and codon preferences were similar. Mutation hotspot analysis identified four highly variable regions, which can potentially be used as molecular markers to identify Artemisia species. Phylogenetic analysis showed that the five Artemisia species investigated in this study were sister branches to each other, and individuals of each species formed a monophyletic clade. This study shows that the cp genome can provide distinguishing features to help identify closely related Artemisia species and has the potential to serve as a universal super barcode for plant identification.

An Artemisia ordosica extract: Effects on growth performance, immune, and inflammatory response in lipopolysaccharide-challenged broilers

Artemisia ordosica has been applied as a traditional Chinese/Mongolian medicine for treating csertain inflammatory ailments. This study was conducted to investigate the effect of Artemisia ordosica alcohol extract (AOAE) supplemented in diets on growth performance, immune, and inflammatory response in lipopolysaccharide (LPS)-challenged broilers. A total of 240 one-day-old Arbor Acre male broilers were randomly allotted into 5 groups with 6 replicates (n = 8), which were basal diet group (CON), LPS-challenge and basal diet group (LPS), LPS-challenge and the basal diet added with low (500 mg/kg), middle (750 mg/kg), and high (1,000 mg/kg) dose of AOAE groups (AOAE-L, AOAE-M, and AOAE-H), respectively. On d 16, 18, 20, 22, 24, 26, and 28, all broilers were injected intra-abdominally either with LPS or an equivalent amount of saline. Results showed that dietary AOAE alleviated the LPS-induced decrease in average daily gain and average daily feed intake in the broilers (P < 0.05). Dietary AOAE supplementation reversed the increased spleen index and the decreased bursa index in LPS-challenged broilers (P < 0.05). Moreover, feeding AOAE could mitigate the elevation of IL-1β in serum, liver, and spleen, IL-2 in serum and liver, IL-6 in serum and spleen, and the decrease of IgG in spleen, IgM in serum, liver, and spleen, and IL-4 in serum of the LPS-challenged broilers (P < 0.05). This study also showed that AOAE supplementation alleviated the increase of mRNA expression of TLR4, MyD88, TRAF6, NF-κB p65, NF-κB p50, IL-1β, and IL-6, and the decrease of gene expression of IκBα and PPARγ in liver and/or spleen of broilers challenged by LPS (P < 0.05). We speculated that AOAE administration could effectively alleviate LPS-induced inflammation via decreasing over-production of proinflammatory cytokines, ultimately relieving the growth inhibition of broilers caused by LPS. In conclusion, 1,000 mg/kg AOAE has a strong capacity to enhance immunity and inhibit inflammation, and can be used as a potential novel feed additive with applications in treating inflammation-related diseases and bacterial infection in broilers.