Oroxindin inhibits macrophage NLRP3 inflammasome activation in DSS-induced ulcerative colitis in mice via suppressing TXNIP-dependent NF-κB pathway

D-mannose alleviates intervertebral disc degeneration through glutamine metabolism

BACKGROUND

Intervertebral disc degeneration (IVDD) is a multifaceted condition characterized by heterogeneity, wherein the balance between catabolism and anabolism in the extracellular matrix of nucleus pulposus (NP) cells plays a central role. Presently, the available treatments primarily focus on relieving symptoms associated with IVDD without offering an effective cure targeting its underlying pathophysiological processes. D-mannose (referred to as mannose) has demonstrated anti-catabolic properties in various diseases. Nevertheless, its therapeutic potential in IVDD has yet to be explored.

METHODS

The study began with optimizing the mannose concentration for restoring NP cells. Transcriptomic analyses were employed to identify the mediators influenced by mannose, with the thioredoxin-interacting protein (Txnip) gene showing the most significant differences. Subsequently, small interfering RNA (siRNA) technology was used to demonstrate that Txnip is the key gene through which mannose exerts its effects. Techniques such as colocalization analysis, molecular docking, and overexpression assays further confirmed the direct regulatory relationship between mannose and TXNIP. To elucidate the mechanism of action of mannose, metabolomics techniques were employed to pinpoint glutamine as a core metabolite affected by mannose. Next, various methods, including integrated omics data and the Gene Expression Omnibus (GEO) database, were used to validate the one-way pathway through which TXNIP regulates glutamine. Finally, the therapeutic effect of mannose on IVDD was validated, elucidating the mechanistic role of TXNIP in glutamine metabolism in both intradiscal and orally treated rats.

RESULTS

In both in vivo and in vitro experiments, it was discovered that mannose has potent efficacy in alleviating IVDD by inhibiting catabolism. From a mechanistic standpoint, it was shown that mannose exerts its anti-catabolic effects by directly targeting the transcription factor max-like protein X-interacting protein (MondoA), resulting in the upregulation of TXNIP. This upregulation, in turn, inhibits glutamine metabolism, ultimately accomplishing its anti-catabolic effects by suppressing the mitogen-activated protein kinase (MAPK) pathway. More importantly, in vivo experiments have further demonstrated that compared with intradiscal injections, oral administration of mannose at safe concentrations can achieve effective therapeutic outcomes.

CONCLUSIONS

In summary, through integrated multiomics analysis, including both in vivo and in vitro experiments, this study demonstrated that mannose primarily exerts its anti-catabolic effects on IVDD through the TXNIP-glutamine axis. These findings provide strong evidence supporting the potential of the use of mannose in clinical applications for alleviating IVDD. Compared to existing clinically invasive or pain-relieving therapies for IVDD, the oral administration of mannose has characteristics that are more advantageous for clinical IVDD treatment.

Dimethyl fumarate covalently modifies Cys673 of NLRP3 to exert anti-inflammatory effects

The NLRP3 inflammasome plays a pivotal role in various chronic inflammation-driven human diseases. However, no drugs specifically targeting NLRP3 inflammasome have been approved by the Food and Drug Administration (FDA) of the United States. In our current study, we showed that dimethyl fumarate (DMF) efficiently suppressed the activation of the NLRP3 inflammasome induced by multiple agonists and covalently modified Cys673 of NLRP3, thereby impeding the interaction between NLRP3 and NEK7. The inhibitory effect of DMF was nullified by anaplerosis of the Cys673 mutant (but not the wild-type) NLRP3 in Nlrp3-/- THP-1 cells. In vivo experiments, DMF demonstrated protective effects in the dextran sodium sulfate (DSS)-induced ulcerative colitis of WT mice, but not in Nlrp3-/- mice. In summary, our study identified DMF as a direct covalent inhibitor of NLRP3 and a potential candidate for the treatment of NLRP3 inflammasome-mediated diseases.

An inulin-type fructan CP-A from Codonopsis pilosula attenuates experimental colitis in mice by promoting autophagy-mediated inactivation of NLRP3 inflammasome

Inulin-type fructan CP-A, a predominant polysaccharide in Codonopsis pilosula, demonstrates regulatory effects on immune activity and anti-inflammation. The efficacy of CP-A in treating ulcerative colitis (UC) is, however, not well-established. This study employed an in vitro lipopolysaccharide (LPS)-induced colonic epithelial cell model (NCM460) and an in vivo dextran sulfate sodium (DSS)-induced colitis mouse model to explore CP-A's protective effects against experimental colitis and its underlying mechanisms. We monitored the clinical symptoms in mice using various parameters: body weight, disease activity index (DAI), colon length, spleen weight, and histopathological scores. Additionally, molecular markers were assessed through enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), immunofluorescence (IF), immunohistochemistry (IHC), and Western blotting assays. Results showed that CP-A significantly reduced reactive oxygen species (ROS), tumor necrosis factor-alpha (TNF-α), and interleukins (IL-6, IL-1β, IL-18) in LPS-induced cells while increasing IL-4 and IL-10 levels and enhancing the expression of Claudin-1, ZO-1, and occludin proteins in NCM460 cells. Correspondingly, in vivo findings revealed that CP-A administration markedly improved DAI, reduced colon shortening, and decreased the production of myeloperoxidase (MPO), malondialdehyde (MDA), ROS, IL-1β, IL-18, and NOD-like receptor protein 3 (NLRP3) inflammasome-associated genes/proteins in UC mice. CP-A treatment also elevated glutathione (GSH) and superoxide dismutase (SOD) levels, stimulated autophagy (LC3B, P62, Beclin-1, and ATG5), and reinforced Claudin-1 and ZO-1 expression, thereby aiding in intestinal epithelial barrier repair in colitis mice. Notably, the inhibition of autophagy via chloroquine (CQ) diminished CP-A's protective impact against colitis in vivo. These findings elucidate that CP-A's therapeutic effect on experimental colitis possibly involves mitigating intestinal inflammation through autophagy-mediated NLRP3 inflammasome inactivation. Consequently, inulin-type fructan CP-A emerges as a promising drug candidate for UC treatment.

Natural products modulate NLRP3 in ulcerative colitis

Ulcerative colitis (UC) is a clinically common, progressive, devastating, chronic inflammatory disease of the intestine that is recurrent and difficult to treat. Nod-like receptor protein 3 (NLRP3) is a protein complex composed of multiple proteins whose formation activates cysteine aspartate protease-1 (caspase-1) to induce the maturation and secretion of inflammatory mediators such as interleukin (IL)-1β and IL-18, promoting the development of inflammatory responses. Recent studies have shown that NLRP3 is associated with UC susceptibility, and that it maintains a stable intestinal environment by responding to a wide range of pathogenic microorganisms. The mainstay of treatment for UC is to control inflammation and relieve symptoms. Despite a certain curative effect, there are problems such as easy recurrence after drug withdrawal and many side effects associated with long-term medication. NLRP3 serves as a core link in the inflammatory response. If the relationship between NLRP3 and gut microbes and inflammation-associated factors can be analyzed concerning its related inflammatory signaling pathways, its expression status as well as specific mechanism in the course of IBD can be elucidated and further considered for clinical diagnosis and treatment of IBD, it is expected that the development of lead compounds targeting the NLRP3 inflammasome can be developed for the treatment of IBD. Research into the prevention and treatment of UC, which has become a hotbed of research in recent years, has shown that natural products are rich in therapeutic means, and multi-targets, with fewer adverse effects. Natural products have shown promise in treating UC in numerous basic and clinical trials over the past few years. This paper describes the regulatory role of the NLRP3 inflammasome in UC and the mechanism of recent natural products targeting NLRP3 against UC, which provides a reference for the clinical treatment of this disease.

Emerging Paradigms in Inflammatory Disease Management: Exploring Bioactive Compounds and the Gut Microbiota

The human gut microbiota is a complex ecosystem of mutualistic microorganisms that play a critical role in maintaining human health through their individual interactions and with the host. The normal gastrointestinal microbiota plays a specific physiological function in host immunomodulation, nutrient metabolism, vitamin synthesis, xenobiotic and drug metabolism, maintenance of structural and functional integrity of the gut mucosal barrier, and protection against various pathogens. Inflammation is the innate immune response of living tissues to injury and damage caused by infections, physical and chemical trauma, immunological factors, and genetic derangements. Most diseases are associated with an underlying inflammatory process, with inflammation mediated through the contribution of active immune cells. Current strategies to control inflammatory pathways include pharmaceutical drugs, lifestyle, and dietary changes. However, this remains insufficient. Bioactive compounds (BCs) are nutritional constituents found in small quantities in food and plant extracts that provide numerous health benefits beyond their nutritional value. BCs are known for their antioxidant, antimicrobial, anticarcinogenic, anti-metabolic syndrome, and anti-inflammatory properties. Bioactive compounds have been shown to reduce the destructive effect of inflammation on tissues by inhibiting or modulating the effects of inflammatory mediators, offering hope for patients suffering from chronic inflammatory disorders like atherosclerosis, arthritis, inflammatory bowel diseases, and neurodegenerative diseases. The aim of the present review is to summarise the role of natural bioactive compounds in modulating inflammation and protecting human health, for their safety to preserve gut microbiota and improve their physiology and behaviour.

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.

Natural flavones from edible and medicinal plants exhibit enormous potential to treat ulcerative colitis

Ulcerative colitis (UC) is a chronic aspecific gut inflammatory disorder that primarily involves the recta and colons. It mostly presents as a long course of repeated attacks. This disease, characterized by intermittent diarrhoea, fecal blood, stomachache, and tenesmus, severely decreases the living quality of sick persons. UC is difficult to heal, has a high recurrence rate, and is tightly related to the incidence of colon cancer. Although there are a number of drugs available for the suppression of colitis, the conventional therapy possesses certain limitations and severe adverse reactions. Thus, it is extremely required for safe and effective medicines for colitis, and naturally derived flavones exhibited huge prospects. This study focused on the advancement of naturally derived flavones from edible and pharmaceutical plants for treating colitis. The underlying mechanisms of natural-derived flavones in treating UC were closely linked to the regulation of enteric barrier function, immune-inflammatory responses, oxidative stress, gut microflora, and SCFAs production. The prominent effects and safety of natural-derived flavones make them promising candidate drugs for colitis treatment.

Disulfiram with Cu2+ alleviates dextran sulfate sodium-induced ulcerative colitis in mice

Background: Disulfiram (DSF), a Food and Drug Administration (FDA)-approved drug for chronic alcohol addiction, has anti-inflammatory effects that help prevent various cancers, and Cu²⁺ can enhance the effects of DSF. Inflammatory bowel diseases (IBD) are characterized by chronic or recurrent relapsing gastrointestinal inflammation. Many drugs targeting the immune responses of IBD have been developed, but their application has many problems, including side effects and high costs. Therefore, there is an urgent need for new drugs. In this study, we investigated the preventive effects of DSF+Cu²⁺ on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. Methods: The anti-inflammatory effects were investigated using the DSS-induced colitis mouse model and lipopolysaccharide (LPS)-induced macrophages. DSS-induced TCRβ^-/- mice were used to demonstrate the effect of DSF in conjunction with Cu²⁺ on CD4⁺ T cell-secreted interleukin 17 (IL-17). In addition, the effect of DSF+Cu²⁺ on intestinal flora was studied by 16S rRNA microflora sequencing. Results: DSF and Cu²⁺ could significantly reverse the symptom of DSS-induced UC in mice, such as weight loss, disease activity index score, colon length shortening, and reversal of colon pathological changes. DSF and Cu²⁺ could inhibit colonic macrophage activation by blocking the nuclear factor kappa B (NF-κB) pathway, reducing nucleotide-binding oligomerization domain, leucine-rich repeat and pyrin domain-containing 3 (NLRP3)-inflammasome-derived interleukin 1 beta (IL-1β) secretion and caspase-1 (CASP1) activation, and decreasing IL-17 secretion by CD4⁺ T cells. Moreover, the treatment of DSF and Cu²⁺ could protect the intestinal barrier by reversing the expression of tight junction proteins, zonula occluden-1 (ZO-1), occludin, and mucoprotein-2 (MUC2). Additionally, DSF+Cu²⁺ could reduce the abundance of harmful bacteria and increase beneficial bacteria in the intestinal tract of mice, effectively improving intestinal microecology. Conclusion: Our study evaluated the effect of DSF+Cu²⁺ on the immune system and gut microbiota in colonic inflammation and highlighted its potential to treat UC in the clinic.

Progress on Regulation of NLRP3 Inflammasome by Chinese Medicine in Treatment of Ulcerative Colitis

Ulcerative colitis (UC) is a chronic, non-specific intestinal disease that not only affects the quality of life of patients and their families but also increases the risk of colorectal cancer. The nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome is an important component of inflammatory response system, and its activation induces an inflammatory cascade response that is involved in the development and progression of UC by releasing inflammatory cytokines, damaging intestinal epithelial cells, and disrupting the intestinal mucosal barrier. Chinese medicine (CM) plays a vital role in the prevention and treatment of UC and is able to regulate NLRP3 inflammasome. Many experimental studies on the regulation of NLRP3 inflammasome mediated by CM have been carried out, demonstrating that CM formulae with main effects of clearing heat, detoxifying toxicity, drying dampness, and activating blood circulation. Flavonoids and phenylpropanoids can effectively regulate NLRP3 inflammasome. Other active components of CM can interfere with the process of NLRP3 inflammasome assembly and activation, leading to a reduction in inflammation and UC symptoms. However, the reports are relatively scattered and lack systematic reviews. This paper reviews the latest findings regarding the NLRP3 inflammasome activation-related pathways associated with UC and the potential of CM in treating UC through modulation of NLRP3 inflammasome. The purpose of this review is to explore the possible pathological mechanisms of UC and suggest new directions for development of therapeutic tools.

Treatment Effects of Natural Products on Inflammatory Bowel Disease In Vivo and Their Mechanisms: Based on Animal Experiments

Inflammatory bowel disease (IBD) is a chronic, non-specific inflammatory disease of the intestine that can be classified as ulcerative colitis (UC) and Crohn's disease (CD). Currently, the incidence of IBD is still increasing in developing countries. However, current treatments for IBD have limitations and do not fully meet the needs of patients. There is a growing demand for new, safe, and highly effective alternative drugs for IBD patients. Natural products (NPs) are used in drug development and disease treatment because of their broad biological activity, low toxicity, and low side effects. Numerous studies have shown that some NPs have strong therapeutic effects on IBD. In this paper, we first reviewed the pathogenesis of IBD as well as current therapeutic approaches and drugs. Further, we summarized the therapeutic effects of 170 different sources of NPs on IBD and generalized their modes of action and therapeutic effects. Finally, we analyzed the potential mechanisms of NPs for the treatment of IBD. The aim of our review is to provide a systematic and credible summary, thus supporting the research on NPs for the treatment of IBD and providing a theoretical basis for the development and application of NPs in drugs and functional foods.

Therapeutic interventions target the NLRP3 inflammasome in ulcerative colitis: Comprehensive study

One of the significant health issues in the world is the prevalence of ulcerative colitis (UC). UC is a chronic disorder that mainly affects the colon, beginning with the rectum, and can progress from asymptomatic mild inflammation to extensive inflammation of the entire colon. Understanding the underlying molecular mechanisms of UC pathogenesis emphasizes the need for innovative therapeutic approaches based on identifying molecular targets. Interestingly, in response to cellular injury, the NLR family pyrin domain containing 3 (NLRP3) inflammasome is a crucial part of the inflammation and immunological reaction by promoting caspase-1 activation and the release of interleukin-1β. This review discusses the mechanisms of NLRP3 inflammasome activation by various signals and its regulation and impact on UC.

Ferulic acid relieved ulcerative colitis by inhibiting the TXNIP/NLRP3 pathway in rats

Ulcerative colitis (UC) is a disorder of the bowel that is characterized by a chronic inflammatory response. The traditional Chinese herbal medicine ferulic acid (FA) is known for its antioxidant, antiapoptotic, and antiinflammatory properties. However, its role in UC is still unclear. Thus, the current study was conducted to investigate the role of FA in UC. Rats were treated with 2,4,6-triabrobenzene sulfonic acid to induce UC and subjected to FA. Human intestinal microvascular endothelial cells (HIMECs) were treated with tumor necrosis factor-α (TNF-α) and pretreated with FA. Pathological changes in colonic tissues were visualized via hematoxylin-eosin staining. Enzyme linked immunosorbent assay was conducted to detect interleukin (IL)-6, IL-12, and IL-1β levels. Cell morphology was visualized by using a microscope, and viability was detected by using MTT. The percentage of apoptosis was detected via flow cytometry. Western blot analysis was performed to detect the expression of the apoptosis-related proteins thioredoxin-interacting protein (TXNIP) and NOD-like receptor pyrin domain-containing 3 (NLRP3). In vivo FA administration alleviated intestinal injury in UC rats and inhibited inflammatory factor levels (IL-6, IL-12, and IL-1β), apoptosis-related protein expression (caspase-1 and caspase-3) and the TXNIP/NLRP3 signaling pathway. In vitro, TNF-α treatment reduced HIMEC viability, increased cell apoptosis and inflammatory factor levels and activated the TXNIP/NLRP3 signaling pathway. However, FA treatment restored the viability of HIMECs, reduced TNF-α-induced cell apoptosis and inflammation and inhibited the TXNIP/NLRP3 signaling pathway. Furthermore, with increasing FA concentration, the effects were stronger. In summary, FA inhibits the inflammatory injury of endothelial cells in ulcerative colitis or alleviates TNF-α-induced HIMEC injury by inhibiting the TXNIP/NLRP3 signaling pathway.

Physiological and Pathophysiological Roles of Thioredoxin Interacting Protein: A Perspective on Redox Inflammation and Metabolism

Significance: Thioredoxin interacting protein (TXNIP) is a member of the arrestin fold superfamily with important cellular functions, including cellular transport, mitochondrial energy generation, and protein cycling. It is the only arrestin-domain protein known to covalently bind to thioredoxin and plays roles in glucose metabolism, inflammation, apoptosis, and cancer. Recent Advances: The crystal structure of the TXNIP-thioredoxin complex provided details about this fascinating interaction. Recent studies showed that TXNIP is induced by endoplasmic reticulum (ER) stress, activates NLR family pyrin domain containing 3 (NLRP3) inflammasomes, and can regulate glucose transport into cells. The tumor suppressor role of TXNIP in various cancer types and the role of TXNIP in fructose absorption are now described. Critical Issues: The influence of TXNIP on redox state is more complex than its interaction with thioredoxin. Future Directions: It is incompletely understood which functions of TXNIP are thioredoxin-dependent. It is also unclear whether TXNIP binding can inhibit glucose transporters without endocytosis. TXNIP-regulated control of ER stress should also be investigated further. Antioxid. Redox Signal. 38, 442-460.

Anticancer potential of phytochemicals from Oroxylum indicum targeting Lactate Dehydrogenase A through bioinformatic approach

In recent years, small molecule inhibition of LDHA (Lactate Dehydrogenase A) has evolved as an appealing option for anticancer therapy. LDHA catalyzes the interconversion of pyruvate and lactate in the glycolysis pathway to play a crucial role in aerobic glycolysis. Therefore, in the current investigation LDHA was targeted with bioactive phytochemicals of an ethnomedicinally important plant species Oroxylum indicum (L.) Kurz. A total of 52 phytochemicals were screened against LDHA protein through molecular docking, ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) assay and molecular dynamics simulation to reveal three potential lead compounds such as Chrysin-7-O-glucuronide (-8.2 kcal/mol), Oroxindin (-8.1 kcal/mol) and Oroxin A (-8.0 kcal/mol). ADMET assay unveiled favorable pharmacokinetic, pharmacodynamic and toxicity properties for all the lead compounds. Molecular dynamics simulation exhibited significant conformational stability and compactness. MM/GBSA free binding energy calculations further corroborated the selection of top candidates where Oroxindin (-46.47 kcal/mol) was found to be better than Chrysin-7-O-glucuronide (-45.72 kcal/mol) and Oroxin A (-37.25 kcal/mol). Aldolase reductase and Xanthine dehydrogenase enzymes were found as potential drug targets and Esculin, the FDA approved drug was identified as structurally analogous to Oroxindin. These results could drive in establishing novel medications targeting LDHA to fight cancer.

Treatment of ulcerative colitis with Wu-Mei-Wan by inhibiting intestinal inflammatory response and repairing damaged intestinal mucosa

BACKGROUND

Wu-Mei-Wan (WMW), a traditional Chinese medicine, has been applied in the treatment of gastrointestinal diseases with long-term diarrhea and mucopurulent bloody stool as the main symptoms since ancient times. Studies have shown that WMW inhibits intestinal inflammation, repairs damaged intestinal mucosa, resists colon necrosis, and resists intestinal fibrosis. However, the specific mechanism of action is not yet clear.

OBJECTIVE

Ulcerative colitis (UC), an intestinal disease with intestinal inflammation and injury as the main pathological manifestations, is one of the high-risk factors for colon cancer. Inhibiting the inflammatory response and promoting colonic epithelial repair are critical to the treatment of UC. However, there is still a lack of remedies with satisfactory curative effects. In this study, the role of WMW in dextran sulfate sodium (DSS)-induced colitis in mice and its related mechanisms are discussed from two aspects: intestinal inflammation and tissue repair.

METHODS

DSS was used to induce colitis in mice and the therapeutic effect of WMW was analyzed by disease activity score, histopathological score, colon length measurement, serum cytokine detection, and flow cytometry. Macrophage activation and colonic stem cell proliferation were observed by immunohistochemistry. The expression of critical molecules in macrophage activation and colonic stem cell proliferation signaling pathways in colon tissue was detected with immunohistochemistry, immunofluorescence staining, RT-qPCR, and Western blot.

RESULTS

WMW could significantly alleviate DSS-induced colitis. We showed that WMW could reduce disease activity, reduce pathological scores, limit weight loss, inhibit colon shortening, inhibit inflammatory factor secretion, attenuate inflammatory response, and promote the repair of damaged colonic epithelium. WMW inhibited the activation of colonic macrophages, and its mechanism might be inhibiting the Notch/NF-κB/NLRP3 pathway; WMW promoted the proliferation of colonic stem cells, and its mechanism was associated with the regulation of the Hippo/YAP signaling pathway.

CONCLUSION

The results of this study suggested that WMW could treat UC via a mechanism that inhibited the intestinal inflammatory response and repaired damaged intestinal mucosa.

Sesquiterpene lactones-rich fraction from Aucklandia lappa Decne. alleviates dextran sulfate sodium induced ulcerative colitis through co-regulating MAPK and Nrf2/Hmox-1 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Aucklandia lappa Decne. (ALDE) is the general name for Asteraceae plants Yunmuxiang, which has traditionally been proven to have the efficacy in relieving depression by regulating qi, alleviating cold by warming, attenuating pain in stomach and relieving diarrhea in intestines. Therefore, ALDE is always recommended as an herbal remedy for gastrointestinal dysfunction.

AIM OF THE STUDY

The purpose of this study was to explore the therapeutic potential and mechanism of action of the sesquiterpene lactone-rich fraction (SLRF) of ALDE extracts in vivo and in vitro.

MATERIALS AND METHODS

An aqueous extract (AE) and SLRF of ALDE were prepared and the contents of the main components were quantified by high performance liquid chromatography (HPLC). The therapeutic effects of the extracts were evaluated in C57BL/6 mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC). Body weight, disease activity index (DAI), and colon length were recorded, and histopathological changes in the colon were characterized using hematoxylin and eosin (H&E) staining. The in vitro anti-inflammatory activity and possible mechanisms of the two main sesquiterpene lactones in ALDE (costunolide and dehydrocostus lactone) were studied by quantitative proteomic analysis. Finally, based on bioinformatic analysis, we used polymerase chain reaction (PCR), immunofluorescence, and western blot experiments to verify the anti-inflammatory mechanism of the extracts in C57BL/6 mice.

RESULTS

The SLRF of ALDE significantly improved the pathological symptoms and inflammatory pathology of UC, whereas the AE had a weak protective effect. In RAW264.7 cells stimulated with lipopolysaccharide (LPS), costunolide and dehydrocostus lactone significantly reduced the mRNA levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, suggesting that these two sesquiterpene lactones had strong anti-inflammatory activity. Quantitative proteomics results indicated that the anti-inflammatory mechanism of these lactones was associated with the NF-κB/MAPK and Nrf2-Hmox-1 pathways. These results were further validated in SLRF-treated mice.

CONCLUSION

This study confirmed that the SLRF of ALDE exerted protective activity against UC by regulating the Nrf2-Hmox-1, NF-κB, and MAPK pathways.

Inflammasome-targeting natural compounds in inflammatory bowel disease: Mechanisms and therapeutic potential

Inflammatory bowel disease (IBD), mainly including Crohn’s disease and ulcerative colitis, seriously affects human health and causes substantial social and economic burden. The pathogenesis of IBD is still not fully elucidated, whereas recent studies have demonstrated that its development is associated with the dysfunction of intestinal immune system. Accumulating evidence have proven that inflammasomes such as NLRP3 and NLRP6 play a prominent role in the pathogenesis of IBD. Thus, regulating the activation of inflammasomes have been considered to be a promising strategy in IBD treatment. A number of recent studies have provided evidence that blocking inflammasome related cytokine IL-1β can benefit a group of IBD patients with overactivation of NLRP3 inflammasome. However, therapies for targeting inflammasomes with high efficacy and safety are rare. Traditional medical practice provides numerous medical compounds that may have a role in treatment of various human diseases including IBD. Recent studies demonstrated that numerous medicinal herb derived compounds can efficiently prevent colon inflammation in animal models by targeting inflammasomes. Herein, we summarize the main findings of these studies focusing on the effects of traditional medicine derived compounds on colitis treatment and the underlying mechanisms in regulating the inflammasomes. On this basis, we provide a perspective for future studies regarding strategies to improve the efficacy, specificity and safety of available herbal compounds, and to discover new compounds using the emerging new technologies, which will improve our understanding about the roles and mechanisms of herbal compounds in the regulation of inflammasomes and treatment of IBD.

Ainsliadimer C, a disesquiterpenoid isolated from Ainsliaea macrocephala, ameliorates inflammatory responses in adipose tissue via Sirtuin 1-NLRP3 inflammasome axis

Interleukin-1β (IL-1β), a key pro-inflammatory cytokine, is majorly produced by macrophages through NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome, which has been identified as the culprit to deteriorate the inflammatory crosstalk between macrophages and adipocytes. Ainsliadimer C (AC) is a disesquiterpenoid isolated from Ainsliaea macrocephala. In the current study, we investigated the effects of AC on adipose tissue inflammation in co-culture of macrophages and adipocytes in vitro as well as in LPS-treated mice in vivo. We showed that AC (20-80 µM) dose-dependently inhibited the secretion of IL-1β from LPS plus ATP-stimulated THP-1 macrophages by inhibiting the activation of NLRP3 inflammasome. Furthermore, we found that AC treatment activated NAD⁺-dependent deacetylase Sirtuin 1 (SIRT1), resulting in reduced acetylation level of NLRP3. Molecular modeling analysis revealed that binding of AC to sirtuin-activating compound-binding domain increased the affinity of the substrate to the catalytic domain of SIRT1. Moreover, AC (80 µM) significantly attenuated macrophage-conditioned medium-induced inflammatory responses in 3T3-L1 adipocytes. In LPS-induced acute inflammatory mice, administration of AC (20, 60 mg·kg^-1·d^-1, ip) for 5 days significantly suppressed the pro-inflammatory cytokine levels in serum and epididymal white adipose tissue (eWAT), attenuated macrophage infiltration into eWAT, and mitigated adipose tissue inflammation. The beneficial effects of AC were blocked by co-administration of a selective SIRT1 inhibitor EX-527 (10 mg·kg^-1·d^-1). Taken together, AC suppresses NLRP3-mediated IL-1β secretion through activating SIRT1, leading to attenuated inflammation in macrophages and adipose tissue, which might be a candidate to treat obesity-associated metabolic diseases.

Trans-10-Hydroxy-2-Decenoic Acid Alleviates Dextran Sulfate Sodium-Induced Colitis in Mice via Regulating the Inflammasome-Mediated Pyroptotic Pathway and Enhancing Colonic Barrier Function

SCOPE

The objective of this study is to explore the effects of 10-hydroxy-2-decenoic acid (10-HDA), the major fatty acid in royal jelly, on dextran sodium sulfate (DSS)-induced mice ulcerative colitis (UC) and its potential mechanism of action.

METHODS AND RESULTS

Forty male C57BL/6 mice are randomly divided into five experimental groups: control, DSS, DSS + 25 (or 100)mg kg^-1  d^-1 10-HDA, and DSS + 200 mg kg^-1  d^-1 mesalazine (ME). UC is induced in mice using 2.5% DSS in drinking water for 7 days. During the induction, these UC mice are orally administrated 10-HDA or ME per day. Meanwhile, lipopolysaccharide (LPS)/adenosine-triphosphate (ATP)-stimulated THP1 cells are used as a model to test the effects of 10-HDA. 10-HDA reduces DSS-induced pathological damage, reactive oxygen species (ROS) accumulation, neutrophil infiltration, and cytokine production in colonic tissue. Compared with the DSS group, the expressions of thioredoxin interacting protein (TXNIP), NOD-like receptor family pyrin domain containing 3 (NLRP3), apoptosis-associated speck-like protein containing a caspase-recruitment domain (ASC), cysteinyl aspartate specific proteinase-1 (Caspase-1), gasdermin-D (GSDMD), N-terminal domain of gasdermin-D (N-GSDMD), interleukin-1β (IL-1β), and interleukin-18 (IL-18) in the colon are decreased after administration of 10-HDA. 10-HDA also elevates the barrier integrity and the expressions of zonula occludens-1 (ZO-1) and Occludin in colonic epithelium exposed to DSS. In THP1 cells, the inflammasome-mediated pyroptosis induced by LPS/ATP is inhibited by 10-HDA pretreatment.

CONCLUSION

10-HDA alleviates DSS-induced colitis by regulating the NLRP3 inflammasome-mediated pyroptotic pathway and enhancing colonic barrier function.

Melatonin, an endogenous hormone, modulates Th17 cells via the reactive-oxygen species/TXNIP/HIF-1α axis to alleviate autoimmune uveitis

Background

Melatonin, an indoleamine produced by the pineal gland, plays a pivotal role in maintaining circadian rhythm homeostasis. Recently, the strong antioxidant and anti-inflammatory properties of melatonin have attracted attention of researchers. We evaluated the therapeutic efficacy of melatonin in experimental autoimmune uveitis (EAU), which is a representative animal model of human autoimmune uveitis.

Methods

EAU was induced in mice via immunization with the peptide interphotoreceptor retinoid binding protein 1–20 (IRBP_1–20). Melatonin was then administered via intraperitoneal injection to induce protection against EAU. With EAU induction for 14 days, clinical and histopathological scores were graded to evaluate the disease progression. T lymphocytes accumulation and the expression of inflammatory cytokines in the retinas were assessed via flow cytometry and RT-PCR, respectively. T helper 1 (Th1), T helper 17 (Th17), and regulatory T (Treg) cells were detected via flow cytometry for both in vivo and in vitro experiments. Reactive-oxygen species (ROS) from CD4 + T cells was tested via flow cytometry. The expression of thioredoxin-interacting protein (TXNIP) and hypoxia-inducible factor 1 alpha (HIF-1α) proteins were quantified via western blot.

Results

Melatonin treatment resulted in notable attenuation of ocular inflammation in EAU mice, evidenced by decreasing optic disc edema, few signs of retinal vasculitis, and minimal retinal and choroidal infiltrates. Mechanistic studies revealed that melatonin restricted the proliferation of peripheral Th1 and Th17 cells by suppressing their transcription factors and potentiated Treg cells. In vitro studies corroborated that melatonin restrained the polarization of retina-specific T cells towards Th17 and Th1 cells in addition to enhancing the proportion of Treg cells. Pretreatment of retina-specific T cells with melatonin failed to induce EAU in naïve recipients. Furthermore, the ROS/ TXNIP/ HIF-1α pathway was shown to mediate the therapeutic effect of melatonin in EAU.

Conclusions

Melatonin regulates autoimmune T cells by restraining effector T cells and facilitating Treg generation, indicating that melatonin could be a hopeful treatment alternative for autoimmune uveitis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-022-02477-z.

Picroside II alleviates DSS-induced ulcerative colitis by suppressing the production of NLRP3 inflammasomes through NF-κB signaling pathway

CONTEXT

Ulcerative colitis (UC) is a common acute or chronic intestinal disease with the imbalance of inflammation. Picroside II (P-II) exerts the protective role in various inflammation-related diseases. However, the effect of P-II on UC is still unclear.

OBJECTIVE

To explore the effect of P-II on UC and its potential mechanism.

MATERIALS AND METHODS

Human monocytic leukemia cell line THP-1 were treated with phorbol ester (PMA) to differentiate into macrophage. The differentiated THP-1 cells were hatched with LPS combined with ATP or Nigericin to activate the NLRP3 inflammasome in vitro. The UC model was constructed by injection of DSS into mice.

RESULTS

The maximum non-toxic concentration of P-II on THP-1 cells was 60 μM. LPS combined with ATP or Nigericin stimulated the production of IL-1β, which was antagonized by P-II treatment. Meanwhile, P-II administration interfered the aggregation of ASC and the assembly of NLRP3 inflammasomes. Also, P-II treatment reduced the LPS and ATP-induced elevation of the relative protein expression of NLRP3, pro-caspase-1, IL-1β and p-p65/p65, and the concentration of TNF-α and IL-6. Besides, the NF-κB specific inhibitor BAY-117082 notably repressed the LPS together with ATP-enhanced the relative protein expression of NLRP3, caspase-1 and IL-1β. Moreover, in vivo results showed that P-II relieved the DDS-induced UC, as evidenced by the improvement of mice weight, DAI and pathological scores. In addition, P-II treatment notably decreased DDS-promoted expression of NLRP3 inflammasomes and inflammatory factors in vivo.

CONCLUSION

P-II alleviated DSS-induced UC by repressing the production of NLRP3 inflammasomes via NF-κB signaling pathway.

Efficacy and Safety of Probiotics Combined With Traditional Chinese Medicine for Ulcerative Colitis: A Systematic Review and Meta-Analysis

Background: The combination of probiotics and traditional Chinese medicine (TCM) is a prospective therapy for ulcerative colitis (UC), and its efficacy and safety need to be urgently evaluated.

Objective: This study aims to comprehensively assess the efficacy and safety of probiotics combined with TCM for the treatment of UC.

Methods: The Pubmed, EMBASE, Cochrane library, China Academic Journals (CNKI), Wan-fang database, Chinese biomedical literature service system (CBM), and Chinese Science and Technology Journals (CQVIP) were searched. Subgroup analysis were designed in accordance with different control drugs, treatment courses, and types of probiotics. The Review Manager software (version 5.4.1) was utilized for statistical analysis.

Results: 14 original studies containing 1,154 patients were analyzed and showed that probiotics with TCM was more effective than 5-aminosalicylic acid (5-ASA), probiotics or TCM used individually. Moreover, probiotics combined with TCM could inhibit the intestinal inflammation, reduce the recurrence rate and the incidence of adverse events. The subgroup analysis showed that a mixture of different probiotics was more effective than a single strain.

Conclusion: It is suggested that probiotics combined with TCM could effectively control clinical symptoms, inhibit intestinal inflammatory response, and finally slow down the disease progress and reduce the disease recurrence with less adverse events. The mixture of different probiotics used in conjunction with individually tailored TCM is a potential clinical strategy for UC.

Kakonein restores hyperglycemia‐induced macrophage digestion dysfunction through regulation of cathepsin B‐dependent NLRP3 inflammasome activation

In hyperglycemia‐induced complications, macrophages play important roles in disease progression, and altered digestion is a key feature that dictates macrophage function. Recent evidence indicates that kakonein (Ka) possesses anti‐inflammatory activities for hyperglycemia‐induced complication. In this study, we established a mouse model of Nlrp3^+/+ and Nlrp3^−/− hyperglycemia and administering Ka, primary culture macrophages were tested by engulfing and digesting microbes. The role of macrophages in the cathepsin B–NLRP3 pathway involved in the mechanism of Ka in restoring macrophage digestion function was investigated using biochemical analyses, molecular biotechnology, and microbiology. Ka restored the function of macrophage digestion, which were same characterized by Nlrp3^−/− mice. Meanwhile, kakonein could decrease NLRP3 inflammasome products expression and NLRP3/ASC or NLRP3/Casp1 colocalization in macrophage. Interestingly, Ka suppressed inflammasome response not by reducing NLRP3 and ASC expression but by reducing cathepsin B release and activation. And Ka restored macrophage digestion and inhibited NLRP3 inflammasome activation consistent with cathepsin B inhibitor. It is concluded that Ka reduced the release of lysosomal cathepsin B and consequently inhibited NLRP3 inflammasome activation to prevent macrophage digestion. Hence, Ka may contribute to new targets for treatment of hyperglycemia‐associated dysfunction of macrophage digestion and development of innovative drugs.

Modelling and targeting mitochondrial protein tyrosine phosphatase 1: a computational approach

The present research scintillates on the homology modelling of rat mitochondrial protein tyrosine phosphatase 1 (PTPMT1) and targeting its activity using flavonoids through a computational docking approach. PTPMT1 is a dual-specificity phosphatase responsible for protein phosphorylation and plays a vital role in the metabolism of cardiolipin biosynthesis, insulin regulation, etc. The inhibition of PTPMT1 has also shown enhanced insulin levels. The three-dimensional structure of the protein is not yet known. The homology modelling was performed using SWISS-MODEL and Geno3D webservers to compare the efficiencies. The PROCHECK for protein modelled using SWISS-MODEL showed 91.6% of amino acids in the most favoured region, 0.7% residues in the disallowed region that was found to be significant compared to the model built using Geno3D. 210 common flavonoids were docked in the modelled protein using the AutoDock 4.2.6 along with a control drug alexidine dihydrochloride. Our results show promising candidates that bind protein tyrosine phosphatase 1, including, prunin (- 8.66 kcal/mol); oroxindin (- 8.56 kcal/mol); luteolin 7-rutinoside (- 8.47 kcal/mol); 3(2H)-isoflavenes (- 8.36 kcal/mol); nicotiflorin (- 8.29 kcal/mol), ranked top in the docking experiments. We predicted the pharmacokinetic and Lipinski properties of the top ten compounds with the lowest binding energies. To further validate the stability of the modelled protein and docked complexes molecular dynamics simulations were performed using Desmond, Schrodinger for 150 ns in conjunction with MM-GBSA. Thus, flavonoids could act as potential inhibitors of PTPMT1, and further, in-vitro and in-vivo studies are essential to complete the drug development process.

The Communication Between Intestinal Microbiota and Ulcerative Colitis: An Exploration of Pathogenesis, Animal Models, and Potential Therapeutic Strategies

Ulcerative Colitis (UC) is a chronic inflammatory bowel disease. The prolonged course of UC and the lack of effective treatment management make it difficult to cure, affecting the health and life safety of patients. Although UC has received more attention, the etiology and pathogenesis of UC are still unclear. Therefore, it is urgent to establish an updated and comprehensive understanding of UC and explore effective treatment strategies. Notably, sufficient evidence shows that the intestinal microbiota plays an important role in the pathogenesis of UC, and the treating method aimed at improving the balance of the intestinal microbiota exhibits a therapeutic potential for UC. This article reviews the relationship between the genetic, immunological and microbial risk factors with UC. At the same time, the UC animal models related to intestinal microbiota dysbiosis induced by chemical drugs were evaluated. Finally, the potential value of the therapeutic strategies for restoring intestinal microbial homeostasis and treating UC were also investigated. Comprehensively, this study may help to carry out preclinical research, treatment theory and methods, and health management strategy of UC, and provide some theoretical basis for TCM in the treatment of UC.

The Effects of Sishen Wan on T Cell Responses in Mice Models of Ulcerative Colitis Induced by Dextran Sodium Sulfate

Currently, it is unclear whether Sishen Wan (SSW) could modulate the balance of Th1 cells, Th17 cells, and Tregs and we evaluated the effects of SSW on T cell responses in mice models of ulcerative colitis (UC). The mice models of acute UC (4% dextran sodium sulfate (DSS), 8 days) and chronic UC (3% DSS, 16 days) with SSW were assayed. Colon tissues were collected for immunohistochemical analysis, enzyme linked immunosorbent assay (ELISA), and flow cytometry (FCM). The expressions of cytokines associated with Tregs, transcription factors of Th17 cells, the frequencies of Th1 cells, Th17 cells, and Tregs, and the functional plasticity of Th17 cells were detected. The frequency of IFN-γ⁺ T cells was not changed significantly with SSW treatment in acute DSS. In chronic models, the frequency of IFN-γ⁺ T cells was downregulated with SSW. Meanwhile, the levels of RORγt and the frequency of IL-17A⁺ Th17 cells showed no significant differences after SSW treatment. Despite no significant effect on the transdifferentiation of Th17 cells in chronic UC models, SSW transdifferentiated Th17 cells into IL-10⁺ Th17 cells and downregulated IFN-γ⁺ Th17 cells/IL-10⁺ Th17 cells in acute DSS. Moreover, there were no significant changes of cytokines secreted by Tregs in acute DSS after SSW treatment, but SSW facilitated the expressions of IL-10 and IL-35, as well as development of IL-10⁺ Tregs in chronic DSS. SSW showed depressive effects on the immunoreaction of Th17 cells and might promote the conversion of Th17 cells into IL-10⁺ Th17 cells in acute UC, while it inhibited the excessive reaction of Th1 cells, facilitated the development of Tregs, and enhanced the anti-inflammatory effects in chronic UC.

Tricholoma matsutake-derived peptide WFNNAGP protects against DSS-induced colitis by ameliorating oxidative stress and intestinal barrier dysfunction

Inflammatory bowel disease (IBD) is a non-specific, chronic inflammatory disease of the intestine. The precise etiology and mechanism underlying the pathogenesis of IBD have not been elucidated. In this study, we investigated the mechanisms through which the Tricholoma matsutake-derived peptide, WFNNAGP, exerts protective effects on the inflammatory response and oxidative stress in a dextran sodium sulfate (DSS)-induced IBD mouse model. WFNNAGP significantly attenuated colitis symptoms in mice, including weight loss, diarrhea, shortened colon, bloody stools, and histopathological changes. WFNNAGP significantly ameliorated the DSS-induced oxidative damage, showing scavenging activity against hydroxyl and DPPH radicals (23.67 ± 4.11% and 34.53 ± 2.45%), increased SOD activity (191.48 ± 4.35 U per mg prot), and decreased MDA activity (1.61 ± 0.24 nmol per mg prot). In addition, WFNNAGP improved the inflammatory response by inhibiting MPO and pro-inflammatory cytokine expression and protected the barrier function by promoting the expression of occludin and ZO-1 in the colon. Western blotting showed that WFNNAGP reduced the inflammatory response by downregulating NF-κB expression and inhibiting the formation and activation of NLRP3 and caspase-1. Thus, WFNNAGP may reduce colonic inflammation in mice by enhancing oxidative defense systems and barrier function and may be a promising candidate for IBD intervention.

Hepatic small extracellular vesicles promote microvascular endothelial hyperpermeability during NAFLD via novel-miRNA-7

BACKGROUND

A recent study has reported that patients with nonalcoholic fatty liver disease (NAFLD) are more susceptible to coronary microvascular dysfunction (CMD), which may predict major adverse cardiac events. However, little is known regarding the causes of CMD during NAFLD. In this study, we aimed to explore the role of hepatic small extracellular vesicles (sEVs) in regulating the endothelial dysfunction of coronary microvessels during NAFLD.

RESULTS

We established two murine NAFLD models by feeding mice a methionine-choline-deficient (MCD) diet for 4 weeks or a high-fat diet (HFD) for 16 weeks. We found that the NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome-dependent endothelial hyperpermeability occurred in coronary microvessels during both MCD diet and HFD-induced NAFLD. The in vivo and in vitro experiments proved that novel-microRNA(miR)-7-abundant hepatic sEVs were responsible for NLRP3 inflammasome-dependent endothelial barrier dysfunction. Mechanistically, novel-miR-7 directly targeted lysosomal associated membrane protein 1 (LAMP1) and promotes lysosomal membrane permeability (LMP), which in turn induced Cathepsin B-dependent NLRP3 inflammasome activation and microvascular endothelial hyperpermeability. Conversely, a specific novel-miR-7 inhibitor markedly improved endothelial barrier integrity. Finally, we proved that steatotic hepatocyte was a significant source of novel-miR-7-contained hepatic sEVs, and steatotic hepatocyte-derived sEVs were able to promote NLRP3 inflammasome-dependent microvascular endothelial hyperpermeability through novel-miR-7.

CONCLUSIONS

Hepatic sEVs contribute to endothelial hyperpermeability in coronary microvessels by delivering novel-miR-7 and targeting the LAMP1/Cathepsin B/NLRP3 inflammasome axis during NAFLD. Our study brings new insights into the liver-to-microvessel cross-talk and may provide a new diagnostic biomarker and treatment target for microvascular complications of NAFLD.

Photodynamic Therapy of Novel Photosensitizer Ameliorates TNBS-Induced Ulcerative Colitis via Inhibition of AOC1

Ulcerative colitis (UC), a chronic, nonspecific inflammatory bowel disease characterized by continuous and diffuse inflammatory changes in the colonic mucosa, requires novel treatment method. Photodynamic therapy (PDT), as a promising physico-chemical treatment method, were used to treat UC rats’ model with novel photosensitizer LD₄ in this paper, the treatment effect and mechanism was investigated. LD₄-PDT could improve the survival rate of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced UC model rats, decrease expression of interleukin (IL)-6, IL-1, tumor necrosis factor (TNF)-α, malondialdehyde (MDA), myeloperoxidase (MPO) and increase the expression of glutathione (GSH) and superoxide oxidase (SOD), while protecting the integrity of the intestinal epithelium. LD₄-PDT treatment could rebuild the intestinal microflora composition and reprogram the colonic protein profiles in TNBS-induced rats to almost the normal state. Proteomics analysis based upon TNBS-induced UC model rats revealed that Amine oxidase copper-containing 1 (AOC₁) was a potential target of LD₄-PDT. Novel photosensitizer agent LD₄-PDT represents an efficient treatment method for UC, and AOC₁ may be a promising target.

Shaoyao decoction attenuates DSS-induced ulcerative colitis, macrophage and NLRP3 inflammasome activation through the MKP1/NF-κB pathway

BACKGROUND

Shaoyao decoction (SYD), a traditional Chinese medicine prescription that originated in the Jin-Yuan Dynasty, has shown effects in treating ulcerative colitis. However, the underlying mechanism is unclear. We combined network pharmacology with molecular biology technology to detect the mechanism underlying the effect of SYD on ulcerative colitis. We combined network pharmacology with molecular biology technology to detected the further mechanism in SYD effect on ulcerative colitis.

PURPOSE

In this study, we investigated the mechanism by which SYD exerts a protective effect against ulcerative colitis in vivo and in vitro.

STUDY DESIGN AND METHODS

We focused on two aspects of the mechanism by which SYD relieves ulcerative colitis, regulation of the MAPK cascade and the NF-κB signaling pathway, through analysis of the "active ingredient-target-disease" network followed by GO enrichment and KEGG pathway analysis according to network pharmacology. Mice with ulcerative colitis underwent 5% dextran sulfate sodium (DSS), and the RAW 264.7 cell model was used to identify important targets.

RESULTS

We found that after 5% DSS treatment, the inflammation indexes and the expression of NLRP3-related proteins were increased concomitant with the loss of mucins and occludin. Treatment with SYD (2.25 g/kg, BW) significantly improved the expression of mucins and occludin after DSS at the protein and transcriptional levels. Furthermore, SYD treatment significantly reduced NF-κB P65 and P38 expression, thus exerting a great antinecrotic effect, as revealed by TUNEL staining and Western blotting. The beneficial effects of SYD were almost canceled by NSC 95397 (an inhibitor of mitogen-activated protein kinase phosphatase-1 (MKP1)) after DSS treatment in vivo or LPS treatment in vitro. In addition, treatment with SYD reduced caspase-1 activity and rescued the release of ASC and GSDMD, thus inhibiting the assembly of NLRP3 and maintaining the integrity of the intestinal barrier. We also conducted in vitro experiments in the LPS-induced RAW 264.7 cell model and found that cells incubated with 1 mg/ml SYD for 24 h possessed the highest cell viability. Next, we incubated 1 mg/ml SYD for 24 h after treatment with 1 µg/ml LPS for 6 h. We showed that 1 mg/ml SYD displayed anti-inflammatory and anti-necrotic effects through the NLRP3, NF-κB P65 and P38 pathways, and the effects of SYD were also inhibited by 10 nM NSC 95397.

CONCLUSION

These results demonstrate that SYD has protective effects against ulcerative colitis and alleviates pyroptosis by inhibiting the MKP1/NF-κB/NLRP3 pathway.

Epigallocatechin gallate (EGCG) attenuates staphylococcal alpha-hemolysin (Hla)-induced NLRP3 inflammasome activation via ROS-MAPK pathways and EGCG-Hla interactions

Alpha-hemolysin (Hla), the virulence factor secreted by Staphylococcus aureus (S. aureus), plays a critical role in infection and inflammation, which is a severe health burden worldwide. Therefore, it is necessary to develop a drug against Hla. Epigallocatechin gallate (EGCG), a polyphenol extracted from green tea, has excellent anti-inflammatory activity. In this study, we investigated the inhibitory effect of EGCG on Hla-induced NLRP3 inflammasome activation in vitro and in vivo and elucidated the potential molecular mechanism. We found that EGCG attenuated the hemolysis of Hla by inhibiting its secretion. Besides, EGCG significantly decreased overproduction of ROS and activation of MAPK signaling pathway induced by Hla, thereby markedly attenuating the expression of NLRP3 inflammasome-related proteins in THP-1 cells. Notably, EGCG could spontaneously bind to Hla with affinity constant of 1.71 × 10-4 M, thus blocking the formation of the Hla heptamer. Moreover, Hla-induced expression of NLRP3, ASC and caspase-1 protein and generation of IL-1β and IL-18 in the damaged liver tissue of mice were also significantly suppressed by EGCG in a dose-dependent manner. Collectively, EGCG could be a promising candidate for alleviating Hla-induced the activation of NLRP3 inflammasome, depending on ROS mediated MAPK signaling pathway, and inhibition of Hla secretion and heptamer formation. These findings will enlighten the applications of EGCG to reduce the S. aureus infection by targeting Hla in food and related pharmaceutical fields.

CP-25 exerts therapeutic effects in mice with dextran sodium sulfate-induced colitis by inhibiting GRK2 translocation to downregulate the TLR4-NF-κB-NLRP3 inflammasome signaling pathway in macrophages

Deficiency of G protein-coupled receptor kinase 2 (GRK2) was found to protect mice from dextran sulfate sodium (DSS)-induced colitis. Paeoniflorin-6'-O-benzene sulfonate (CP-25) has been shown to exert anti-inflammatory immune regulatory effects in animal models of inflammatory autoimmune disease. This study aimed to investigate the of GRK2 in the pathogenesis of ulcerative colitis (UC) and its effects on macrophage polarization, macrophage subtype regulation of intestinal barrier function, and therapeutic effects of CP-25 in mice with DSS-induced colitis. We found imbalanced macrophage polarization, intestinal barrier dysfunction, and abnormal activation of GRK2 and TLR4-NF-κB-NLRP3 inflammasome signaling pathway in the colonic mucosa of patients with UC. CP-25, restored the damaged intestinal barrier function by inhibiting the transmembrane region of GRK2 in macrophages stimulated by lipopolysaccharides. CP-25 exerted therapeutic effects by ameliorating clinical manifestation, regulating macrophage polarization, and restoring abnormally activated TLR4-NF-κB-NLRP3 inflammasome signaling pathway by inhibiting GRK2. These data suggest the pathogenesis of UC may be related to the imbalance of macrophage polarization, which leads to abnormal activation of TLR4-NF-κB-NLRP3 inflammasome signaling pathway mediated by GRK2 and destruction of the intestinal mucosal barrier. CP-25 confers therapeutic effects on colitis by inhibiting GRK2 translocation to induce the downregulation of TLR4-NF-κB-NLRP3 inflammasome signaling in macrophages.

Transcriptional enhancement of GBP-5 by BATF aggravates sepsis-associated liver injury via NLRP3 inflammasome activation

Strong inflammatory response triggered by the activation of the innate immune system is one typical characteristic of sepsis-associated liver injury (SALI). Guanylate-binding protein 5 (GBP-5) is a component of cell-autonomous immunity and known to be associated with inflammation. Currently, whether GBP-5 participates in SALI and its roles in this disease are yet to be investigated. Using a lipopolysaccharide (LPS)-induced SALI mouse model, we found GBP-5 was highly expressed in LPS-treated mice, and its expression was tightly related to the serum concentrations of live injury markers and inflammatory cytokines, liver damage scores by H&E staining, and amounts of apoptotic hepatocytes by TUNEL staining. Moreover, GBP-5 overexpression was found to aggravate LPS-induced SALI by promoting the activation of NLR family pyrin domain containing 3 (NLRP3) inflammasome, then facilitated the production of pro-inflammatory cytokines, eventually induced hepatocyte cell death. Direct transcriptional activation of GBP-5 by basic leucine zipper ATF-like transcription factor (BATF) was identified and further validated. This study unveils a transcriptional upregulation of GBP-5 by interacting with BATF, which promotes the progression of LPS-induced SALI through NLRP3 inflammasome activation, and provides novel therapeutic insights for halting the progression of liver injury in various liver diseases.

Identification of anti-inflammatory compounds from Zhongjing formulae by knowledge mining and high-content screening in a zebrafish model of inflammatory bowel diseases

BACKGROUND

Inflammatory bowel diseases (IBD) are chronic relapsing intestinal inflammations with increasing global incidence, and new drug development remains in urgent demand for IBD management. To identify effective traditional Chinese medicine (TCM) formulae and compounds in IBD treatment, we innovatively combined the techniques of knowledge mining, high-content screening and high-resolution mass spectrometry, to conduct a systematic screening in Zhongjing formulae, which is a large collection of TCM prescriptions with most abundant clinical evidences.

METHODS

Using Word2vec-based text learning, the correlations between 248 Zhongjing formulae and IBD typical symptoms were analyzed. Next, from the top three formulae with predicted relationship with IBD, TCM fractions were prepared and screened on a transgenic zebrafish IBD model for their therapeutic effects. Subsequently, the chemical compositions of the fraction hits were analyzed by mass spectrometry, and the major compounds were further studied for their anti-IBD effects and potential mechanisms.

RESULTS

Through knowledge mining, Peach Blossom Decoction, Pulsatilla Decoction, and Gegen Qinlian Decoction were predicted to be the three Zhongjing formulae mostly related to symptoms typical of IBD. Seventy-four fractions were prepared from the three formulae and screened in TNBS-induced zebrafish IBD model by high-content analysis, with the inhibition on the intestinal neutrophil accumulation and ROS level quantified as the screening criteria. Six herbal fractions showed significant effects on both pathological processes, which were subsequently analyzed by mass spectrometry to determine their chemical composition. Based on the major compounds identified by mass spectrometry, a second-round screen was conducted and six compounds (palmatine, daidzin, oroxyloside, chlorogenic acid, baicalin, aesculin) showed strong inhibitory effects on the intestinal inflammation phenotypes. The expression of multiple inflammatory factors, including il1β, clcx8a, mmp and tnfα, were increased in TNBS-treated fish, which were variously inhibited by the compounds, with aesculin showing the most potent effects. Moreover, aesculin and daidzin also upregulated e-cadherin's expression.

CONCLUSION

Taken together, we demonstrated the regulatory effects of several TCM formulae and their active compounds in the treatment of IBD, through a highly efficient research strategy, which can be applied in the discovery of effective TCM formulae and components in other diseases.