The role of Nrf2 in the pathogenesis and treatment of ulcerative colitis

MS-275 facilitates osseointegration in osteoporotic rats by mitigating oxidative stress via activation of the miR-200a/Keap1/Nrf2 signaling pathway

OBJECTIVES

Osteoporosis, a prevalent metabolic bone disease affecting millions worldwide. Although MS-275 has been reported to inhibit oxidative stress, its ability to protect osteoblasts from oxidative stress damage has yet to be clarified. This study investigated whether MS-275 can inhibit oxidative stress and promote osteogenesis by activating the miRNA-200a/Keap1/Nrf2 signaling pathway.

METHODS

In vitro, MC3T3-E1 cells underwent induction with carbonyl cyanide 3-chlorophenylhydrazone, leading to the establishment of an oxidative stress model, investigating the underlying mechanism. In vivo, using a rat model of ovariectomized osteoporosis, evaluating the effects of MS-275.

RESULTS

In vitro, MS-275 treatment of oxidation-induced MC3T3-E1 cells resulted in up-regulation of osteoblast protein, increased expression of miRNA-200a, increased binding of miRNA-200a to Keap1 mRNA, decreased expression of Keap1 protein, and dissociation of Nrf2 from Keap1. The expressions of total Nrf2, nuclear Nrf2 and HO-1 were increased, mitochondrial function was enhanced, and oxidative damage was reduced. However, these effects were reversed after interference with miRNA-200a. In vivo,MS-275 effectively enhanced the microstructural features of distal femoral trabecular bone, increased the mineralization capacity of osteoblasts, and promoted bone formation.

DISCUSSION

MS-275 can reverse oxidative stress-induced cell damage, promote bone healing, and improve osteoporosis by activating the miRNA-200a/Keap1/Nrf2 pathway.

Discovery of β-amino acid substituted naphthalene sulfonamide derivatives as potent Kelch-like ECH-associated protein 1-nuclear factor erythroid 2-related factor 2 (Keap1-Nrf2) protein-protein interaction inhibitors for ulcerative colitis management

The transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) is a key regulator of cellular defense system against oxidative insults. Directly inhibiting the Kelch-like ECH-associated protein 1 (Keap1)-Nrf2 protein-protein interaction (PPI) has emerged as a promising approach to activate Nrf2 for the treatment of diseases associated with oxidative stress. Herein, we identified β-amino acids as privileged structural fragments for designing novel naphthalene sulfonamide-based Keap1-Nrf2 PPI inhibitors. Comprehensive structure-activity relationship (SAR) exploration identified compound 19 as the optimal inhibitor with an IC50 of 0.55 μM for disrupting the Keap1-Nrf2 interaction and a Kd of 0.50 μM for binding to Keap1. Further studies demonstrated that 19 effectively activated the Nrf2-regulated cytoprotective system and provided protective effects against dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in both in vitro and in vivo models. These findings highlight the potential of β-amino acid substituted naphthalene sulfonamide Keap1-Nrf2 inhibitor 19 as a prospective therapeutic agent for UC via Keap1 targeting.

The protective effect of naringenin on ulcerative colitis in mice through increasing Nrf2 pathway activity

Ulcerative colitis (UC) is a chronic inflammatory disease with an increasing prevalence worldwide. Naringenin (NAR) has been proven effective in preventing UC, but its mechanism has not been fully elucidated. In this study, network pharmacology and bioinformatics methods are used to screen the genes associated with NAR and UC. A mouse model of dextran sulfate sodium (DSS)-induced UC is established. After treatment with NAR, the disease activity index (DAI) is scored, and colonic histopathology is observed via hematoxylin-eosin (HE) staining. The expressions of the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway and inflammation-related factors in the colons of UC mice are examined via western blot analysis and immunohistochemistry (IHC). The results of the animal experiments reveal that the model group of UC mice present the most severe weight loss and the highest DAI scores. After the administration of NAR, weight loss is alleviated, and DAI scores are reduced ( P < 0.05). NAR improves pathological manifestations in the mouse colon, such as reducing inflammatory cell infiltration and restoring goblet cell loss ( P < 0.05). NAR significantly increases the protein expression levels of Nrf2, heme oxygenase 1 (HO-1), and NAD(P)H dehydrogenase [quinone] 1 (NQO1) in the colon ( P < 0.05) but decreases the protein expression levels of nuclear factor kappa-B (NF-κB), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) ( P < 0.05), thus alleviating the inflammatory response in UC model mice.

Ganoderic Acid Ameliorates Ulcerative Colitis by Improving Intestinal Barrier Function via Gut Microbiota Modulation

Ulcerative colitis (UC) is a chronic and recurrent gastrointestinal disease that affects millions of humans worldwide and imposes a huge social and economic burden. It is necessary to find safe and efficient drugs for preventing and treating UC. The aim of this study was to determine whether ganoderic acid (GA), the main bioactive components of Ganoderma lucidum, has preventive and therapeutic effect on UC in a dextran sulfate sodium (DSS)-induced UC mouse model. Our experimental results showed that GA significantly ameliorated the body weight loss and disease activity index (DAI) of UC mice. GA significantly restored 11% of the colon length and 69% of the spleen index compared to UC mice. GA significantly decreased the intestinal inflammatory response and improved the barrier function of the intestine by upregulating the tight junction proteins Zonula occludens-1 (ZO-1), occludin and claudin-1. A co-housing experiment showed that gut microbiota accounted for the therapeutic activity of GA on UC, which was confirmed by fecal microbiota transplantation from GA-treated mice to the UC mice. Furthermore, 16S rDNA high-throughput sequencing of fecal bacteria showed that GA significantly enriched the abundance of Lactobacillus, Oscillospira, Odoribacter and Ruminococcus, which were positively correlated with colon length. Furthermore, this study found the functional metabolites, including Indole-3-acetaldehyde (IAAld), Glutamine (Gln) and Glutathione (GSH), reduced barrier damage in the Caco-2 cell model. In conclusion, this study suggests that GA could ameliorate UC by improving intestinal barrier function via modulating gut microbiota and associated metabolites.

Network pharmacology and in vivo study: Unraveling the therapeutic mechanisms of Panax ginseng in potentially treating ulcerative colitis

BACKGROUND

Ulcerative colitis (UC), a chronic and challenging condition, necessitates the development of more effective treatments owing to the unsatisfactory efficacy and side effects associated with current medications. Traditional Chinese medicine (TCM), known for its multi-stage and multi-targeted approach, has a long history in treating gastrointestinal diseases and offering a promising alternative UC treatment. Panax ginseng (P. ginseng), a commonly used remedy for UC in TCM, exemplifies this potential, although the specific components and mechanisms through which its therapeutic effects are exerted remain to be fully elucidated, highlighting the need for further research to unlock its full potential as a treatment option.

AIM

To investigate the key constituents and biological pathways through which P. ginseng exerts therapeutic effects on UC.

METHODS

Network pharmacology investigated the UC-alleviating mechanism of P. ginseng, including "active ingredient-target-disease" network analysis, and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses. Panaxadiol (PD; active ingredient of P. ginseng) was tested in a mouse model of 3% dextran sulfate sodium-induced UC, with assessments of body weight, Disease Activity Index scores, and colon length. Colitis and intestinal barrier integrity were analyzed via hematoxylin-eosin and Alcian blue and periodic acid-Schiff staining, immunohistochemistry, real time-quantitative PCR, and western blotting.

RESULTS

By integrating and analyzing the targets of P. ginseng and UC, 15 critical hub genes were discovered. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed the mechanisms involved to be linked to MAPK and PI3K-Akt signaling. Among the 10 main active ingredients identified as potentially effective, PD was most abundant and was validated in vivo to mitigate weight loss, reduce Disease Activity Index scores, and prevent colon shortening. PD also reduced inflammation and suppressed expression of pro-inflammatory cytokines and mediators. In addition, PD increased expression of mucin and tight junction proteins. Ultimately, PD counteracted effects of dextran sulfate sodium by inhibiting phosphorylation of NF-кB and MAPK, while increasing phosphorylation of AMPK and expression of NRF2 and NQO1.

CONCLUSION

PD alleviates colitis and aids intestinal barrier repair, partly via modulation of the MAPK/NF-кB and AMPK/NRF2/NQO1 pathways. These findings also suggest new research methods for treatment of UC with TCM.

Mare milk and fermented mare milk alleviate dextran sulfate sodium salt-induced ulcerative colitis in mice by reducing inflammation and modulating intestinal flora

Mare milk (MM) and fermented mare milk (FM) are specialized animal milks with high nutritional value, containing a variety of functionally active substances that are capable of resisting inflammatory responses and oxidative stress. However, little relevant research on the maintenance of intestinal homeostasis has been performed. This study aimed to investigate the effects of MM and FM on the prevention of dextran sulfate sodium salt (DSS)-induced ulcerative colitis in a mouse model and to preliminarily elucidate the underlying mechanisms. The results showed that MM and FM had different degrees of protective effects against the damage caused by DSS and alleviated ulcerative colitis by inhibiting weight loss, reducing colon length shortening, and restoring intestinal structure. Additionally, MM and FM maintained intestinal tight junction protein levels to repair barrier function, downregulated inflammatory cytokines (e.g., IL-1β, TNF-α, IL-6, and iNOS) and bolstered the body's antioxidant defense system. Moreover, MM and FM regulated dysregulation of the intestinal microenvironment by improving the diversity of the gut microbiota and reshaping its structure, including increasing the proportion of Firmicutes and Bacteroidetes and the relative abundance of beneficial bacterial genera (e.g., Akkermansia). In summary, MM and FMM can serve as dietary resources for preventing ulcerative colitis and maintaining intestinal homeostasis.

Macadamia oil alleviates dextran sulfate sodium-induced ulcerative colitis in mice via activating the Nrf2/Ho-1 pathway

Macadamia nut oil (MO) fatty acids are mainly composed of oleic acid and palmitoleic acid, which have a variety of health benefits. This study established an ulcerative colitis (UC) mouse model using dextran sulfate sodium (DSS), and the ameliorative effects of MO on UC were investigated. The results revealed that MO supplementation mitigated weight loss and colon shortening, increased goblet cell counts, and alleviated histopathologic changes in UC mice. MO significantly increased the intestinal antioxidant levels in UC mice. Moreover, Nrf2 and Ho-1 mRNA and protein expression levels were significantly upregulated in UC mice following treatment with low- and high-dose MO. In contrast, expression levels of Keap1 were significantly downregulated. Lastly, MO inhibited the inflammatory factors (TNF-α, IL-6 and IL-1β) expression in UC mice. These results indicate that MO could enhance colonic antioxidant levels, induce apoptosis, and activate the Nrf2/Ho-1 pathway, thereby ameliorating the pathological injuries associated with UC.

Exploring Chemoprevention in Colorectal Cancer for Patients with Inflammatory Bowel Disease: Mechanisms of Action and Clinical Aspects

Background: Inflammatory bowel diseases (IBDs) have been associated with a higher risk of colorectal cancer (CRC) development and chronic colonic inflammation seems to have a critical role in the pathogenesis of CRC in patients suffering from IBD. In respect to that, surveillance colonoscopy at regular intervals is recommended in patients with colitis. Objective: This review aims to explore the chemopreventive potential of a range of agents, including mesalazine, thiopurines, anti-TNF agents, statins, ursodeoxycholic acid, aspirin, folic acid, and nutraceuticals. Results: These agents target inflammation, oxidative stress, and oncogenic pathways, thereby offering the potential to reduce the risk of CRC in patients with IBD. Anti-TNF agents, such as infliximab and adalimumab, not only reduce colonic inflammation, but also play a protective role against CRC by lessening the carcinogenic effects associated with prolonged inflammatory processes. Furthermore, mesalazine and thiopurines have demonstrated established efficacy, while newer biologics, including interleukin inhibitors, show promising advancements. Although nutraceuticals and dietary interventions require further clinical validation, they offer additional possibilities for non-pharmacological prevention. Conclusion: Despite progress, knowledge gaps persist regarding the long-term safety, optimal dosing, and combined use of these agents. A significant reduction in the incidence of CRC in patients with IBD could be achieved by advancing chemoprevention and personalizing strategies.

Cannabidiol Alleviates Intestinal Fibrosis in Mice with Ulcerative Colitis by Regulating Transforming Growth Factor Signaling Pathway

Objective

The aim of this study is to investigate the protective effect of Cannabidiol (CBD) on DSS-induced colitis in C57BL/6 mice and its related pathways.

Methods

A mouse model of ulcerative colitis (US) was induced by DSS. Enzyme-linked immunosorbent assay (ELISA), quantitative reverse transcription polymerase-chain reaction (qRT-PCR), Western blot (WB) and immunofluorescence (IF) were used to identify the key factors involved in inflammatory response, oxidative stress and intestinal fibrosis. In addition, we transfected si-RNA into CCD-18Co cells.

Results

The research suggests that CBD significantly improves intestinal inflammation by up-regulating the nuclear factor erythroid 2-related factor 2 (Nrf2) expression, inhibiting the classical Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κb) pathway, and inhibiting the release of IL-6 (Interleukin), IL-1β, Tumor Necrosis Factor-α (TNF-α) and other factors. At the same time, CBD plays an antioxidant role by regulating Nrf2/ HO-1 (Heme Oxygenase-1) pathway and activating HO-1 activity. On the other hand, CBD may regulate Transforming growth factor beta (TGF-β)/SMADs signaling pathway by inhibiting the expression of TGF-β1, thereby inhibiting the expression of α-SMA, Collagen1, TIMP1 and other factors, thus playing an anti-fibrotic role. Notably, when Nrf2 is inhibited or lacking, CBD loses the above protective effect against DSS-induced colon injury.

Conclusion

CBD affects the classical NF-κb pathway, Nrf2/ Heme Oxygenase-1 (HO-1) pathway, and Transforming growth factor beta (TGF-β)/SMAD pathway by regulating Nrf2, thereby reducing colonic inflammation and oxidative stress and improving the progression of colonic fibrosis.

Antioxidant and Laxative Effects of Methanol Extracts of Green Pine Cones (Pinus densiflora) in Sprague-Dawley Rats with Loperamide-Induced Constipation

Oxidative stress is the key cause of the etiopathogenesis of several diseases associated with constipation. This study examined whether the green pine cone can improve the symptoms of constipation based on the antioxidant activities. The changes in the key parameters for the antioxidant activity and laxative effects were examined in the loperamide (Lop)-induced constipation of Sprague-Dawley (SD) rats after being treated with the methanol extracts of green pine cone (MPC, unripe fruits of Pinus densiflora). MPC contained several bioactive compounds, including diterpenoid compounds such as dehydroabietic acid, taxodone, and ferruginol. In addition, it exhibited high scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals. These effects of MPC successfully reflected the improvement in nicotinamide adenine dinucleotide phosphate oxidase (NADP) H oxidase transcription, superoxide dismutase (SOD) levels, and nuclear factor erythroid 2-related factor 2 (Nrf2) phosphorylation levels in the mid colon of Lop+MPC-treated SD rats. Furthermore, significant improvements in the stool parameters, gastrointestinal (GI) transit, intestine length, and histopathological structure of the mid colon were detected in the Lop-induced constipation rats after MPC treatment. The other parameters, including the regulators for the adherens junction (AJ) and tight junction (TJ), and GI hormone secretion for laxative effects, were improved significantly in Lop+MPC-treated SD rats. These effects were also verified in Lop+MPC-treated primary rat intestine smooth muscle cells (pRISMCs) through analyses for antioxidant defense mechanisms. Overall, the finding of this study offers novel scientific evidence that MPC could be considered as a significant laxative for chronic constipation based on its antioxidant activity.

Zhumeria majdae essential oil attenuates TNBS-induced colitis in rats by regulating inflammatory and apoptotic pathways

BACKGROUND AND AIM

Zhumeria majdae, a unique native plant of southern Iran, has been traditionally used to treat various health issues. Preclinical studies suggest its therapeutic potential for immunological and inflammatory disorders. This study investigates the effect of Z. majdae essential oil (ZMEO) on TNBS-induced colitis in rats, focusing on the NF-κB/p38 MAPK/Nrf-2 pathway.

EXPERIMENTAL PROCEDURE

Forty-eight male Wistar rats were used, with all groups except the sham group receiving a single intra-rectal dose of TNBS. Three different doses of ZMEO and also 1 mg/kg dexamethasone were administered orally for 2 weeks. Colon tissue was analyzed for ulcer index, histological changes, inflammatory cytokines, apoptotic factors, and levels of NF-κB, p38 MAPK, and Nrf-2.

KEY RESULTS

GC-mass analysis identified 25 compounds with linalool (52.01%) and camphor (31.01%) as the major compounds in ZMEO. ZMEO ameliorated colon injuries, reduced ulcer index, and prevented the elevation of pro-inflammatory cytokines and pro-apoptotic proteins. It also increased the levels of IL-10 and Bcl-2 proteins. Furthermore, ZMEO decreased the expression of p-NF-κB and p38 MAPK while increasing the expression of pNrf-2.

CONCLUSIONS

ZMEO mitigates colon damage associated with IBD by suppressing inflammatory cytokines and pro-apoptotic proteins possibly through modulating the NF-κB/p38 MAPK/Nrf-2 signaling pathway.

Wound healing effect of polydeoxyribonucleotide derived from Hibiscus sabdariffa callus via Nrf2 signaling in human keratinocytes

There has been a growing interest in skin recovery in both the medical and cosmetics fields, leading to an increasing number of studies reporting diverse materials being utilized for this purpose. Among them, polydeoxyribonucleotide (PDRN) is known for its efficacy in skin repair processes, while Hibiscus sabdariffa (HS) is recognized for its antioxidant, hypolipidemic, and wound healing properties, including its positive impact on mammalian skin and cells. We hypothesized that these characteristics may have a germane relationship during the healing process. Consequently, we induced calli from HS and then extracted PDRN for use in treating human keratinocytes. PDRN (5 μg/mL) had considerable wound healing effects and wrinkle improvement effects. To confirm its function at the molecular level, we performed real-time polymerase chain reaction, western blotting, and immunocytochemistry. Furthermore, genes related to wound healing (MMP9, Nrf2, KGF, VEGF, SOD2, and AQP3) were significantly upregulated. Additionally, the protein expression of MMP9, AQP3, and CAT, which are closely related to wound healing and antioxidant cascades, was considerably enhanced. Based on cellular morphology and molecular-level evidence, we propose that PDRN from calli of HS can improve wound healing in human keratinocytes. Furthermore, its potential to serve as a novel material in cosmetic products is demonstrated.

Protective effects of ginsenosides on ulcerative colitis: a meta-analysis and systematic review to reveal the mechanisms of action

BACKGROUND

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon. Ginsenoside may be an ideal agent for UC treatment. However, its efficacy and safety are unknown. We aim to conduct a systematic evaluation to assess the effects and potential mechanisms of ginsenosides in animal models of UC.

METHODS

Six electronic databases will be searched (PubMed, Embase, Web of Science, China Knowledge Network (CNKI), China Science and Technology Journal Database (CQVIP), and Wanfang Data Knowledge). SYRCLE list will be used to assess the quality of literature, and STATA 15.1 for data analysis. Time-dose effects analysis will be used to reveal the time-dosage response relations between ginsenosides and UC.

RESULTS

Ultimately, fifteen studies involving 300 animals were included. Preliminary evidence was shown that ginsenosides could reduce Disease Activity Index (DAI) scores, weight loss, histological colitis score (HCS), spleen weight, Malondialdehyde (MDA), Myeloperoxidase (MPO) activity, interleukin-1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α) and increase colon length (CL), myeloperoxidase (GSH), interleukin 4 (IL-4), interleukin 10 (IL-10), Zonula Occludens-1 (ZO-1) and occludin. Results of time-dose interval analysis indicated that ginsenosides at a dosage of 5-200 mg/kg with an intervention time of 7-28 days were relatively effective.

CONCLUSIONS

Preclinical evidence suggests that ginsenoside is a novel treatment for UC. And the mechanisms of ginsenosides in treating UC may involve anti-inflammatory, antioxidant, barrier protection, intestinal flora regulation, and immune regulation. Although, due to the high heterogeneity, further large-scale and high-quality preclinical studies are needed to examine the protection of ginsenosides against UC.

Serotonin deficiency from constitutive SKN-1 activation drives pathogen apathy

When an organism encounters a pathogen, the host innate immune system activates to defend against pathogen colonization and toxic xenobiotics produced. C. elegans employ multiple defense systems to ensure survival when exposed to Pseudomonas aeruginosa including activation of the cytoprotective transcription factor SKN-1/NRF2. Although wildtype C. elegans quickly learn to avoid pathogens, here we describe a peculiar apathy-like behavior towards PA14 in animals with constitutive activation of SKN-1, whereby animals choose not to leave and continue to feed on the pathogen even when a non-pathogenic and healthspan-promoting food option is available. Although lacking the urgency to escape the infectious environment, animals with constitutive SKN-1 activity are not oblivious to the presence of the pathogen and display the typical pathogen-induced intestinal distension and eventual demise. SKN-1 activation, specifically in neurons and intestinal tissues, orchestrates a unique transcriptional program which leads to defects in serotonin signaling that is required from both neurons and non-neuronal tissues. Serotonin depletion from SKN-1 activation limits pathogen defenses capacity, drives the pathogen-associated apathy behaviors and induces a synthetic sensitivity to selective serotonin reuptake inhibitors. Taken together, our work reveals interesting insights into how animals perceive environmental pathogens and subsequently alter behavior and cellular programs to promote survival.

The Dual Role of NRF2 in Colorectal Cancer: Targeting NRF2 as a Potential Therapeutic Approach

Colorectal cancer (CRC), as the third most common bisexual cancer worldwide, requires urgent research on its underlying mechanisms and intervention methods. NRF2 is an important transcription factor involved in the regulation of redox homeostasis, protein degradation, DNA repair, and other cancer processes, playing an important role in cancer. In recent years, the complex role of NRF2 in CRC has been continuously revealed: on the one hand, it exhibits a chemopreventive effect on cancer by protecting normal cells from oxidative stress, and on the other hand, it also exhibits a protective effect on malignant cells. Therefore, this article explores the dual role of NRF2 and its related signaling pathways in CRC, including their chemical protective properties and promoting effects in the occurrence, development, metastasis, and chemotherapy resistance of CRC. In addition, this article focuses on exploring the regulation of NRF2 in CRC ferroptosis, as well as NRF2 drug modulators (activators and inhibitors) targeting CRC, including natural products, compounds, and traditional Chinese medicine formulations.

Histone deacetylase inhibitor, Trichostatin A mitigates ionizing radiation induced redox imbalance by regulating NRF2/GPX4/PINK1/PARKIN signaling in mice intestine

BACKGROUND

Gastrointestinal-acute radiation syndrome (GI-ARS) caused by moderate to high doses of ionizing radiation exposure contribute to early death in humans. GI injury is also a common adverse effect seen in cancer patients undergoing abdominal/pelvic radiotherapy. Currently, no countermeasure agents have been approved for medical management of GI-ARS. The present study aims to evaluate the mechanism of action of Trichostatin A(TSA), a pan histone deacetylase inhibitor, against radiation-induced GI injury.

METHODS

TSA (150 ng/kg bw) was administered to mice 1 h and 24 h after 15 Gy abdominal irradiation. Expression of various markers of oxidative stress, mitochondrial dysfunction, and apoptosis were checked in the jejunum, and their possible regulation through the Nrf2 signaling pathway was evaluated.

RESULTS

TSA administered post-irradiation (15 Gy + TSA) elevated intestinal total antioxidant and glutathione levels by regulating the expression of Slc7A11 and antioxidant proteins, GCLC, GPX4, and TXNRD1. Improved mitochondrial membrane potential, ATP levels, downregulation of mitochondrial quality control proteins, (PINK1 and PARKIN), and differential regulation of the apoptotic proteins, (BAX, PUMA and BCL2) with reduced intestinal epithelial cell apoptosis in the TSA-adminstered group were observed. TSA also upregulated Nrf2 in the presence of its specific inhibitor, ML385, suggesting its involvement in regulating Nrf2 signaling during oxidative stress induced by radiation in intestine. H & E stained jejunum cross-sections revealed that TSA mitigated radiation-mediated intestinal injury in mice.

CONCLUSIONS

Present findings indicate that TSA is beneficial in mitigating the damaging effects of ionizing radiation in the intestine.

[Sanguinarine alleviates ulcerative colitis in mice by regulating the Nrf2/NF-κB pathway]

OBJECTIVE

To investigate the mechanism of sanguinarine (SA) for alleviating ulcerative colitis (UC) induced by dextran sodium sulfate (DSS) in mice.

METHODS

Male C57BL/6 mouse models of 3.5% DSS-induced UC were randomized for treatment with 1, 5 and 10 mg/kg SA by gavage, 400 mg/kg sulfasalazine by gavage, or 10 mg/kg SA combined with intraperitoneal injection of 30 mg/kg ML385 (a Nrf2 inhibitor). The changes in intestinal inflammation was assessed by monitoring weight changes, disease activity index (DAI) score, colon length measurement, and HE staining. After the treatments, the colon tissues were collected for detection of malondialdehyde (MDA) content using colorimetry, mRNA expressions of inflammatory factors using RT-qPCR, and the expressions of Nrf2, HO-1, Keap-1, p-p65, p65, occludin, and ZO-1 proteins were detected using Western blotting.

RESULTS

SA treatment obviously alleviated weight loss, colon length shortening and DAI score increase and ameliorated structural destruction of the colon glands and colonic crypts in mice with DSSinduced UC. SA intervention significantly decreased the levels of TNF-α, IL-1β and IL-6 mRNA and lowered ROS and MDA levels in the colon tissue of UC mice. The mouse models receiving SA treatment showed significantly increased expressions of Nrf2, HO-1, occludin and ZO-1 and lowered expressions of Keap-1 and P-P65 in the colon tissue without significant changes of p65 expression, and these changes were SA dose-dependent. Treatment with ML385 obviously attenuated the effect of highdose SA for improving UC in the mouse models.

CONCLUSION

SA can improve UC-like enteritis in mice possibly by activating the Nrf2 pathway and inhibiting the NF-κB pathway in the colon tissue.

Mechanism of Action and Therapeutic Implications of Nrf2/HO-1 in Inflammatory Bowel Disease

Oxidative stress (OS) is a key factor in the generation of various pathophysiological conditions. Nuclear factor erythroid 2 (NF-E2)-related factor 2 (Nrf2) is a major transcriptional regulator of antioxidant reactions. Heme oxygenase-1 (HO-1), a gene regulated by Nrf2, is one of the most critical cytoprotective molecules. In recent years, Nrf2/HO-1 has received widespread attention as a major regulatory pathway for intracellular defense against oxidative stress. It is considered as a potential target for the treatment of inflammatory bowel disease (IBD). This review highlights the mechanism of action and therapeutic significance of Nrf2/HO-1 in IBD and IBD complications (intestinal fibrosis and colorectal cancer (CRC)), as well as the potential of phytochemicals targeting Nrf2/HO-1 in the treatment of IBD. The results suggest that the therapeutic effects of Nrf2/HO-1 on IBD mainly involve the following aspects: (1) Controlling of oxidative stress to reduce intestinal inflammation and injury; (2) Regulation of intestinal flora to repair the intestinal mucosal barrier; and (3) Prevention of ferroptosis in intestinal epithelial cells. However, due to the complex role of Nrf2/HO-1, a more nuanced understanding of the exact mechanisms involved in Nrf2/HO-1 is the way forward for the treatment of IBD in the future.

4-Octyl itaconate alleviates dextran sulfate sodium-induced ulcerative colitis in mice via activating the KEAP1-NRF2 pathway

Ulcerative colitis (UC) is a chronic idiopathic inflammatory bowel disease with a relapsing-remitting course. Although its etiology remains unknown, excessive oxidative stress in colon is a major intermediate factor that can promote the progression of UC. In the present study, we investigated the effect and the underlying mechanisms of 4-Octyl itaconate (OI) on dextran sulfate sodium (DSS)-induced UC in mice. Our work identified that OI alleviated the colitis by reducing the oxidative stress and the apoptosis in colon tissue, then increasing the tight junction proteins expression and in turn enhancing the intestinal barrier function, thereby creating less severe inflammatory responses. Moreover, our results demonstrated that OI reduced the Kelch-like ECH-associated protein 1 (KEAP1) expression and subsequent upregulated nuclear factor E2-related factor (NRF2) expression and its nuclear translocation which in turn induced the expression of glutathione S-transferase (GST) and NAD(P)H: quinone oxidoreductase 1 (NQO1). In addition, ML385, a NRF2 antagonist, can inhibit the protective effects of OI on UC, indicating that the role of OI in this colitis model could be dependent on the activation of KEAP1-NRF2 pathway. Notably, OI co-administration significantly enhanced the therapeutic effects of mesalazine or 1400W on UC. Collectively, itaconate may have a great potential for use in the treatment of IBD.

Protective effect of andrographolide against ulcerative colitis by activating Nrf2/HO-1 mediated antioxidant response

Ulcerative colitis (UC) is a recurring inflammatory bowel disease, in which oxidative stress plays a role in its progression, and regulation of the oxidative/antioxidative balance has been suggested as a potential target for the treatment of UC. The aim of this study was to evaluate the protective effect of andrographolide against UC and its potential antioxidant properties by modulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway. Dextran sulfate sodium (DSS) -induced UC mice and the LPS-induced HT29 inflammatory cell model were established to uncover the potential mechanisms of andrographolide. ML385, a Nrf2 inhibitor, was used in both models to assess whether andrographolide exerts a protective effect against UC through the Nrf2/HO-1 pathway. The in vivo experiment showed that andrographolide ameliorated the symptoms and histopathology of DSS-induced mice and restored the expressions of ZO-1, Occludin-1 and Claudin-1. Meanwhile, DSS-induced oxidative stress and inflammation were suppressed by andrographolide treatment, along with the upregulation of key proteins in the Nrf2/HO-1 pathway. In vitro experiments showed that andrographolide attenuated LPS-induced excessive generation of ROS in HT29 cells, reduced inflammatory factors, and upregulated the expression of proteins related to tight junctions and Nrf2/HO-1 pathway. In addition, ML385 abolished the beneficial effect of andrographolide. In conclusion, the protective effect of andrographolide against UC may involve the suppression of oxidative stress and inflammation via the Nrf2/HO-1 pathway.

Protective effects of sinomenine against dextran sulfate sodium-induced ulcerative colitis in rats via alteration of HO-1/Nrf2 and inflammatory pathway

BACKGROUND

Dextran Sulfate Sodium (DSS) induces ulcerative colitis (UC), a type of inflammatory bowel disease (IBD) that leads to inflammation, swelling, and ulcers in the large intestine. The aim of this experimental study is to examine how sinomenine, a plant-derived alkaloid, can prevent or reduce the damage caused by DSS in the colon and rectum of rats.

MATERIAL AND METHODS

Induction of ulcerative colitis (UC) in rats was achieved by orally administering a 2% Dextran Sulfate Sodium (DSS) solution, while the rats concurrently received oral administrations of sinomenine and sulfasalazine. The food, water intake was estimated. The body weight, disease activity index (DAI), colon length and spleen index estimated. Antioxidant, cytokines, inflammatory parameters and mRNA expression were estimated. The composition of gut microbiota was analyzed at both the phylum and genus levels in the fecal samples obtained from all groups of rats.

RESULTS

Sinomenine treatment enhanced the body weight, colon length and reduced the DAI, spleen index. Sinomenine treatment remarkably suppressed the level of NO, MPO, ICAM-1, and VCAM-1 along with alteration of antioxidant parameters such as SOD, CAT, GPx, GR and MDA. Sinomenine treatment also decreased the cytokines like TNF-α, IL-1, IL-1β, IL-6, IL-10, IL-17, IL-18 in the serum and colon tissue; inflammatory parameters viz., PAF, COX-2, PGE2, iNOS, NF-κB; matrix metalloproteinases level such as MMP-1 and MMP-2. Sinomenine significantly (P < 0.001) enhanced the level of HO-1 and Nrf2. Sinomenine altered the mRNA expression of RIP1, RIP3, DRP3, NLRP3, IL-1β, caspase-1 and IL-18. Sinomenine remarkably altered the relative abundance of gut microbiota like firmicutes, Bacteroidetes, F/B ratio, Verrucomicrobia, and Actinobacteria.

CONCLUSION

The results clearly indicate that sinomenine demonstrated a protective effect against DSS-induced inflammation, potentially through the modulation of inflammatory pathways and gut microbiota.

Li-Hong Tang alleviates dextran sodium sulfate-induced colitis by regulating NRF2/HO-1 signaling pathway and gut microbiota

Introduction

Ulcerative colitis (UC) is marked by recurring inflammation. Existing treatments are ineffective and may have toxic side effects. Thus, new therapeutic agents are urgently needed. We studied the botanical formula "Li-Hong Tang (LHT)", which contains two main ingredients, Salvia plebeia R. Br and Rhodiola crenulata (Hook. f. et Thoms.) H. Ohba. In this study, we aimed to identify the effects of LHT on UC and explore its potential mechanism.

Methods

LHT was analyzed using a mass spectrometer (MS). DSS at a dose of 2.5% was utilized to develop UC in mice. The administered groups received low, medium, and high dosages (0.32 g/kg, 0.64 g/kg, and 1.28 g/kg) of LHT and the positive medication, sulfasalazine (0.2 g/kg), respectively. Body weight, disease activity index (DAI) score, colon length, spleen index, serum myeloperoxidase (MPO), nitric oxide (NO), superoxide dismutase (SOD) and inflammatory factor concentrations were monitored. The expression of NRF2 and HO-1 in colonic tissues was evaluated by immunohistochemistry. 16S rDNA sequencing was employed to investigate alterations in the gut microbiota of the mice, aiming to elucidate the extent of LHT's impact.

Results

LHT may ameliorate DSS-induced colitis in mice by lowering inflammation, reducing oxidative stress, restoring the intestinal barrier, and influencing the NRF2/HO-1 pathway. Moreover, LHT treatment exhibited a regulatory effect on the gut microbiota, characterized by elevated levels of Patescibacteria, Verrucomicrobiota, Candidatus_Saccharimonas, Lactobacillus, and Ligilactobacillus levels while decreasing Oscillibacter and Colidextribacter levels. Further study indicated that MPO, NO, and inflammatory factors were positively correlated with Oscillibacter, Colidextribacter, Escherichia-Shigella, Anaerostines, and negatively with Lactobacillus, Clostridiales_unclassified, Candidatus_Saccharimonas, and Patescibacteria. Furthermore, colony network analysis revealed that Lactobacillus was negatively associated with Oscillibacter and Colidextribacter, whereas Oscillibacter was positively related to Colidextribacter.

Conclusion

LHT protects against DSS-induced mice by inhibiting the inflammatory response, oxidative stress, and mucosal injury. The protective role may involve regulating the NRF2/HO-1 signaling pathway and gut microbiota.

Protective effect of FKBP12 on dextran sulfate sodium-induced ulcerative colitis in mice as a tacrolimus receptor

Ulcerative colitis (UC) is a multifactorial intestinal disease with a high incidence. In recent years, there has been an urgent need for pleiotropic drugs with a clear biosafety profile. Tacrolimus (TAC) is an immunosuppressant with stronger in vivo effects and better gastrointestinal absorption and is considered a potential treatment for UC. FKBP12 is a mediator of TAC immunosuppression; however, it is unclear whether it can participate in the development of UC in combination with TAC. The purpose of this study is to preliminarily validate the function of FKBP12 by establishing dextran sulfate sodium (DSS)-induced UC model and TAC treatment. The results revealed that TAC was effective in alleviating DSS-induced UC symptoms such as body weight and disease activity index (DAI). TAC significantly protects colonic tissue and attenuates DSS-induced histomorphological changes. In addition, FKBP12 is down-regulated in the intestinal tissue of DSS-induced UC mice and in serum samples of UC patients. In conclusion, our study revealed that FKBP12 may act as a TAC receptor to have anti-inflammatory and protective effects on DSS-induced UC in mice, which will provide a new option for the treatment of UC.

Serotonin deficiency from constitutive SKN-1 activation drives pathogen apathy

When an organism encounters a pathogen, the host innate immune system activates to defend against pathogen colonization and toxic xenobiotics produced. C. elegans employ multiple defense systems to ensure survival when exposed to Pseudomonas aeruginosa including activation of the cytoprotective transcription factor SKN-1/NRF2. Although wildtype C. elegans quickly learn to avoid pathogens, here we describe a peculiar apathy-like behavior towards PA14 in animals with constitutive activation of SKN-1, whereby animals choose not to leave and continue to feed on the pathogen even when a non-pathogenic and healthspan-promoting food option is available. Although lacking the urgency to escape the infectious environment, animals with constitutive SKN-1 activity are not oblivious to the presence of the pathogen and display the typical pathogen-induced intestinal distension and eventual demise. SKN-1 activation, specifically in neurons and intestinal tissues, orchestrates a unique transcriptional program which leads to defects in serotonin signaling that is required from both neurons and non-neuronal tissues. Serotonin depletion from SKN-1 activation limits pathogen defense capacity, drives the pathogen-associated apathy behaviors and induces a synthetic sensitivity to selective serotonin reuptake inhibitors. Taken together, our work reveals new insights into how animals perceive environmental pathogens and subsequently alter behavior and cellular programs to promote survival.

KEY POINTS

Identify an apathy-like behavioral response for pathogens resulting from the constitutive activation of the cytoprotective transcription factor SKN-1.Uncover the obligate role for serotonin synthesis in both neuronal and non-neuronal cells for the apathy-like state and ability of serotonin treatment to restore normal behaviors.Characterize the timing and tissue specificity of SKN-1 nuclear localization in neurons and intestinal cells in response to pathogen exposure.Define the unique and context-specific transcriptional signatures of animals with constitutive SKN-1 activation when exposed to pathogenic environments.Reveal necessity for both neuronal and non-neuronal serotonin signaling in host survival from pathogen infection.

Anti-oxidant and anti-inflammatory potential of different polymer-based mesalamine delayed-release granules in TNBS-induced ulcerative colitis in wistar rats

Ulcerative colitis (UC) is an inflammatory condition of colon characterized by severe damage to the innermost colon tissues. A number of studies described the use of medication delivery systems based on natural polymers like polysaccharides for the purpose of reaching the colon. In this research, polymer-based mesalamine delayed-release granules (DRGs) were tested for their antioxidant and anti-inflammatory efficacy against UC. Chitosan (C), pectin (P), and pectin-chitosan (PC) mesalamine (M) DRGs were prepared and characterized. Data revealed satisfactory compatibility, flow, packing properties, drug release pattern, and delayed drug release by DRGs. Wistar rats were treated with 2,4,6-trinitrobenzenesulfonic acid (TNBS) (100 mg/kg) via rectal administration. Mesalamine and mesalamine DRGs (50 mg/kg) were administered orally separately for 14 days. Biomarkers of oxidative stress, inflammation, hematological tests, colon profile, and histopathology were performed. The findings demonstrated the good efficacy of the polysaccharides in delivering mesalamine to colon. Mesalamine and mesalamine DRGs based on various polymers showed significant antioxidant and anti-inflammatory effects in rats with UC. Mesalamine granules significantly attenuated colon lipid peroxidation, nitrites, myeloperoxidase activity, and interleukin-1β levels, and improved anti-oxidants (GSH, SOD). Data showed upregulation of Nrf2 activity by mesalamine granules with CM-DRGs showing maximum effect. Mesalamine and different polymer-based mesalamine DRGs significantly attenuated TNBS-induced decline in body weight, ulcer severity, and colon damage. CM-DRGs showed the most pronounced ameliorative effect on colon and hematology parameters via anti-oxidant and anti-inflammatory activities. Chitosan can be used as a carrier for oral colon delivery of mesalamine in DRG formulation for enhanced therapeutic efficacy in UC.

Amelioration of acetic acid-induced ulcerative colitis in rats by cetirizine and loratadine via regulation of the PI3K/Akt/Nrf2 signalling pathway and pro-inflammatory cytokine release

Objectives

Ulcerative colitis is a chronic inflammatory bowel disease (IBD) that causes inflammation and ulcers in the rectum and the innermost layer of the large intestine. Our study aimed to elucidate the ameliorative effect of cetirizine (CTZ) and loratadine (LOR) against acetic acid-induced ulcerative colitis in rats via assessment of the PI3K/p-Akt/Nrf2 signaling pathway and proinflammatory cytokine release.

Materials and Methods

Thirty-two rats were allocated into four groups (n=8). Group (I) was considered normal control. Acetic acid (AA) was injected intrarectally in groups (2-4). Group (2) was kept untreated. Group (3) was administered CTZ (20 mg/kg/day) for 7 days. Group (4) was administered LOR (10 mg/kg/day) for 7 days.

Results

AA showed severe macroscopic colonic lesions associated with increased ulcer number, area, and severity with significantly elevated PI3K, p-Akt, Nrf2, TNF-α, and IL-6 in colorectal tissue as compared to the normal control group. All the aforementioned indicators were greatly improved by CTZ and LOR therapy.

Conclusion

This is the first study to elucidate the ameliorative effect of CTZ and LOR against AA-induced UC in rats. CTZ and LOR treatment mitigates UC via amelioration of the PI3K/p-Akt/Nrf2 pathway and proinflammatory cytokine release.

Diosmetin alleviates neuropathic pain by regulating the Keap1/Nrf2/NF-κB signaling pathway

BACKGROUND

Neuropathic pain, a chronic condition with a high incidence, imposes psychological burdens on both patients and society. It is urgent to improve pain management and develop new analgesic drugs. Traditional Chinese medicine has gained popularity as a method for pain relief. Diosmetin (Dio) is mainly found in Chinese herbal medicines with effective antioxidant, anti-cancer, and anti-inflammatory properties. There are few known mechanisms underlying the effectiveness of Dio in treating neuropathic pain. However, the complete understanding of its therapeutic effect is missing.

PURPOSE

This study aimed to evaluate Dio's therapeutic effects on neuropathic pain models and determine its possible mechanism of action. We hypothesized that Dio may activate antioxidants and reduce inflammation, inhibit the activation of Kelch-like epichlorohydrin-associated protein 1 (Keap1) and nuclear factor-k-gene binding (NF-κB), promote the metastasis of nuclear factor erythroid 2-related factor 2 (Nrf2) and the expression of heme oxygenase 1 (HO-1), thus alleviating the neuropathic pain caused by spinal nerve ligation.

METHODS

Chronic nociceptive pain mouse models were established in vivo by L4 spinal nerve ligation (SNL). Different dosages of Dio (10, 50, 100 mg/kg) were intragastrically administered daily from the third day after the establishment of the SNL model. Allodynia, caused by mechanical stimuli, and hyperalgesia, caused by heat, were assessed using the paw withdrawal response frequency (PWF) and paw withdrawal latency (PWL), respectively. Cold allodynia were assessd by acetone test. RT-PCR was used to detect the content of interleukin-(IL)- 1β, IL-6 and tumor necrosis factor (TNF)-a. Immunofluorescence and western blotting were employed to assess the expression levels of Glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule (Iba1), Keap1, Nrf2, HO-1, and NF-κB p-p65 protein.

RESULTS

Dio administration relieved SNL-induced transient mechanical and thermal allodynia in mice. The protective effect of Dio in the SNL model was associated with its anti-inflammatory and anti-glial responses in the spinal cord. Dio inhibited both inflammatory factors and macrophage activation in the DRG. Furthermore, Dio regulated the Keap1/Nrf2/NF-κB signaling pathway. HO-1 and Nrf2 were upregulated following Dio administration, which also decreased the levels of Keap1 and NF-κB p65 protein.

CONCLUSION

Mice with SNL-induced neuropathic pain were therapeutically treated with Dio. Dio may protect against pain by inhibiting inflammatory responses and improved Keap1/Nrf2/NF-κB pathway. These results highlight the potential therapeutic effect of Dio for the development of new analgesic drugs.

Epigenetic regulation and therapeutic strategies in ulcerative colitis

Ulcerative colitis (UC) is an inflammatory bowel disease, and is characterized by the diffuse inflammation and ulceration in the colon and rectum mucosa, even extending to the caecum. Epigenetic modifications, including DNA methylations, histone modifications and non-coding RNAs, are implicated in the differentiation, maturation, and functional modulation of multiple immune and non-immune cell types, and are influenced and altered in various chronic inflammatory diseases, including UC. Here we review the relevant studies revealing the differential epigenetic features in UC, and summarize the current knowledge about the immunopathogenesis of UC through epigenetic regulation and inflammatory signaling networks, regarding DNA methylation, histone modification, miRNAs and lncRNAs. We also discuss the epigenetic-associated therapeutic strategies for the alleviation and treatment of UC, which will provide insights to intervene in the immunopathological process of UC in view of epigenetic regulation.

Lycium barbarum polysaccharide alleviates DSS-induced chronic ulcerative colitis by restoring intestinal barrier function and modulating gut microbiota

PURPOSE

This study examined the protective effects and mechanism of Lycium barbarum polysaccharides (LBP) in the context of intestinal barrier function and intestinal microbiota in mice with dextran sulfate sodium (DSS)-induced chronic ulcerative colitis (UC).

METHODS

C57BL/6J male mice were assigned to a standard normal diet without DSS (control group), a normal diet with DSS (DSS group, 2% DSS given discontinuously for 3 weeks) or a normal diet supplemented with LBP (1% dry feed weight, LBP group, 2% DSS given discontinuously for 3 weeks) for a total of 8 weeks, at which point colonic tissues and caecal contents were collected.

RESULTS

LBP exerted a significant effect against colitis by increasing body weight, colon length, DAI and histopathological scores. LBP inhibited proinflammatory cytokines (IL-1β, IL-6, iNOS and TNF-α) expression, improved anti-inflammatory cytokine (IL-10) expression, promoted the expression of tight junction proteins (Occludin and ZO-1) via nuclear factor erythroid 2-related factor 2 (Nrf2) activation and decreased Claudin-2 expression to maintain the intestinal mucosal barrier. In addition, the abundances of some probiotics (Ruminococcaceae, Lactobacillus, Butyricicoccus, and Akkermansia) were decreased with DSS treatment but increased obviously with LBP treatment. And LBP reduced the abundance of conditional pathogens associated with UC (Mucispirillum and Sutterella). Furthermore, LBP improved the production of short-chain fatty acids (SCFAs), including acetic acid, propionic acid, butyric acid and isobutyric acid.

CONCLUSION

LBP can alleviate DSS-induced UC by regulating inflammatory cytokines and tight junction proteins. Moreover, LBP promotes probiotics, suppresses conditional pathogens and increases SCFAs production, showing a strong prebiotic effect.

Mechanism of Nrf2 in the treatment of ulcerative colitis via regulating macrophage polarization

Ulcerative colitis (UC) is an inflammatory bowel disease induced by multiple factors, which causes abnormal activation of intestinal immune cells and excessive release of antibodies and inflammatory factors, repeatedly damaging the intestinal mucosa. Macrophages, as innate intestinal immune cells, often maintain the balance of M1/M2 macrophages polarization to normalize the regression inflammation, and the imbalance of their polarization will cause repeated damage of intestinal mucosa and persistent inflammation, which is a main cause of UC. Nuclear factor E2-related factor 2 (Nrf2), as an important regulator of antioxidant and anti-inflammatory, is often used as a target for the treatment of autoimmune diseases.Nrf2 alleviates intestinal high oxidative stress and inflammatory factors by balancing macrophage polarization, which may be of great significance for the prevention and treatment of UC. Summarizing the mechanism of macrophage polarization imbalance on the course of UC and the possible regulatory mechanism of Nrf2 may provide basis for the development of UC targeted therapeutic drugs.