Rutaecarpine inhibits KEAP1-NRF2 interaction to activate NRF2 and ameliorate dextran sulfate sodium-induced colitis

KEAP1-NRF2 protein-protein interaction inhibitors: Design, pharmacological properties and therapeutic potential

The transcription factor nuclear factor erythroid 2-related factor 2 (NRF2) is considered the master regulator of the phase II antioxidant response. It controls a plethora of cytoprotective genes related to oxidative stress, inflammation, and protein homeostasis, among other processes. Activation of these pathways has been described in numerous pathologies including cancer, cardiovascular, respiratory, renal, digestive, metabolic, autoimmune, and neurodegenerative diseases. Considering the increasing interest of discovering novel NRF2 activators due to its clinical application, initial efforts were devoted to the development of electrophilic drugs able to induce NRF2 nuclear accumulation by targeting its natural repressor protein Kelch-like ECH-associated protein 1 (KEAP1) through covalent modifications on cysteine residues. However, off-target effects of these drugs prompted the development of an innovative strategy, the search of KEAP1-NRF2 protein-protein interaction (PPI) inhibitors. These innovative activators are proposed to target NRF2 in a more selective way, leading to potentially improved drugs with the application for a variety of diseases that are currently under investigation. In this review, we summarize known KEAP1-NRF2 PPI inhibitors to date and the bases of their design highlighting the most important features of their respective interactions. We also discuss the preclinical pharmacological properties described for the most promising compounds.

Honokiol Ameliorates DSS-Induced Mouse Colitis by Inhibiting Inflammation and Oxidative Stress and Improving the Intestinal Barrier

Ulcerative colitis (UC) is a multifactor intestinal disease with increased morbidity. Recently, pleiotropic drugs with exact biosafety have been urgently needed. Honokiol (HKL) is the major bioactive component of traditional Chinese medicine "Houpu," with almost no toxic effects and approved anti-inflammation, antioxidant, antispasmodic, etc. effects. This study examined the therapeutic effect of HKL in dextran sulfate sodium- (DSS-) induced experimental colitis. In vivo, C57BL/6 mice received 3% DSS for seven days to generate UC, and HKL was pretreated for five days and given during the whole DSS-induced period. In vitro, RAW264.7 macrophages were stimulated with lipopolysaccharide (LPS) to induce inflammation, and mouse colon epithelial cells (MCEC) were treated with HKL or pretreated with HKL and then stimulated with LPS-induced macrophage supernate to investigate the barrier enhancement roles. HKL significantly ameliorated disease activity index (DAI), colon length, and histopathological scores in DSS-induced colitis. The inflammatory mediators of interleukin 1β (IL-1β), interleukin 6 (IL-6), tumor necrosis factor α (TNF-α), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX2) were decreased, and the tight conjunction proteins were increased in the HKL-treated group both in vivo and in vitro. Above all, HKL can relieve experimental UC through anti-inflammation, antioxidant, and epithelial barrier enhancement roles. These effects were associated with peroxisome proliferator-activated receptor γ (PPARγ)/nuclear factor-κB (NF-κB) p65, sirtuin3 (SIRT3)/adenosine 5'-monophosphate- (AMP-) activated protein kinase (AMPK), and nuclear factor erythroid 2-related factor 2 (NRF2)/heme oxygenase 1 (HO1) signaling pathways. In conclusion, after further clinical studies, HKL may be a promising drug for UC.

The Alleviation of Dextran Sulfate Sodium (DSS)-Induced Colitis Correlate with the logP Values of Food-Derived Electrophilic Compounds

Food-derived electrophilic compounds (FECs) are small molecules with electrophilic groups with potential cytoprotective effects. This study investigated the differential effects of six prevalent FECs on colitis in dextran sodium sulfate (DSS)-induced mice and the underlying relationship with molecular characteristics. Fumaric acid (FMA), isoliquiritigenin (ISO), cinnamaldehyde (CA), ferulic acid (FA), sulforaphane (SFN), and chlorogenic acid (CGA) exhibited varying improvements in colitis on clinical signs, colonic histopathology, inflammatory and oxidative indicators, and Nrf2 pathway in a sequence of SFN, ISO > FA, CA > FMA, CGA. Representative molecular characteristics of the “penetration-affinity−covalent binding” procedure, logP value, Keap1 affinity energy, and electrophilic index of FECs were theoretically calculated, among which logP value revealed a strong correlation with colitis improvements, which was related to the expression of Nrf2 and its downstream proteins. Above all, SFN and ISO possessed high logP values and effectively improving DSS-induced colitis by activating the Keap1−Nrf2 pathway to alleviate oxidative stress and inflammatory responses.

Epoxymicheliolide prevents dextran sulfate sodium-induced colitis in mice by inhibiting TAK1-NF-κB pathway and activating Keap1-NRF2 signaling in macrophages

Ulcerative colitis (UC) is an unspecific colorectal inflammation associated with macrophages overactivation. Therefore, macrophage-targeted treatment has been considered a promising strategy for UC therapy. Epoxymicheliolide (EMCL) is a compound from Aucklandia lappa Decne, a TCM for treating gastrointestinal inflammatory diseases. The purpose of this study is to investigate the therapeutic effect of EMCL on DSS-induced mice colitis through the anti-inflammatory activity on macrophages and its underlying mechanisms. We found that EMCL inhibited the release of NO and PGE₂ by down-regulating the expression of iNOS and COX2, while suppressed the expression of IL-1β, IL-6, and TNF-α in LPS-stimulated RAW264.7 macrophages. EMCL also inhibited NO production in LPS-activated peritoneal macrophages and TNFα-stimulated RAW264.7 cells. Moreover, EMCL blocked the phosphorylation of TAK1, IKKα/β, and IκBα, as well as IκBα degradation, thereby inhibiting the NF-κB pro-inflammatory signaling. Furthermore, EMCL decreased the intracellular ROS, by activating the NRF2 antioxidant pathway. CETSA and molecular docking showed that EMCL might form a covalent bond with Cys174 of TAK1 or Cya151 of Keap1, which may contribute to EMCL-mediated actions. Additionally, a thiol donor β-mercaptoethanol obviously abolished EMCL-mediated actions in vitro, suggesting the crucial role of the α, γ-unsaturated lactone of EMCL on its anti-inflammatory effects. Furthermore, EMCL not only ameliorated symptoms of colitis and colon barrier injury, but also decreased the levels of pro-inflammatory cytokines, MPO, NO, and MDA in DSS-challenged mice. Thus, our study demonstrated that EMCL ameliorated UC by targeting NF-κB and Nrf2 pathways, indicating it may server as a promising drug candidate for UC therapy.

BP5 alleviates endotoxemia-induced acute lung injury by activating Nrf2 via dual regulation of the Keap1-Nrf2 interaction and the Akt (Ser473)/GSK3β (Ser9)/Fyn pathway

Oxidative stress and inflammation play a crucial role in the pathogenesis of acute lung injury (ALI). Previously, pentapeptide bursopentin (BP5, Cys-Lys-Arg-Val-Tyr) was reported to possess significant antioxidant activity and inhibit lipopolysaccharides (LPS)-induced NF-κB activation in vitro, whereas little is known about its effects in vivo. In this study, we explored the effects of BP5 on endotoxemia-induced ALI in mice and the underlying molecular mechanisms. Our studies revealed that BP5 markedly improved survival and effectively alleviated lung injury by reducing overoxidation and excessive inflammatory response in endotoxemia mice. In LPS-stimulated mouse primary macrophages and RAW 264.7 cells, BP5 also exhibited antioxidant and anti-inflammatory properties by enhancing Nrf2 activation. Importantly, these beneficial effects were abolished by Nrf2 knockdown. To further elucidate the underlying mechanisms, we performed localized surface plasmon resonance (LSPR) assays, molecular docking, together with cell-based studies, and found that BP5 inhibited the Keap1-Nrf2 interaction to promote Nrf2 nuclear translocation and activation. Moreover, BP5-induced Nrf2 activation was shown to be accompanied by an increase in the phosphorylation of Akt (at Ser473) and GSK3β (at Ser9), and a decrease in Fyn nuclear accumulation both in vitro and in vivo. Pharmacologically inhibiting phosphorylation of Akt and GSK3β obviously enhanced Fyn nuclear accumulation in RAW 264.7 cells, which partially attenuated the promoting effect of BP5 on Nrf2 nuclear accumulation and activation. Furthermore, In Nrf2^-/- mice, the protective effects of BP5 on the endotoxemia-induced ALI in WT mice were largely vanished. Our findings indicated that BP5 effectively protected endotoxemia-induced ALI against oxidative stress and inflammatory response, which are largely dependent on activation of the Nrf2 pathway. Underlying mechanisms include dual regulation of the Keap-Nrf2 interaction and the Akt (Ser473)/GSK3β (Ser9)/Fyn pathway.

Application of ARE-reporter systems in drug discovery and safety assessment

The human body is continuously exposed to xenobiotics and internal or external oxidants. The health risk assessment of exogenous chemicals remains a complex and challenging issue. Alternative toxicological test methods have become an essential strategy for health risk assessment. As a core regulator of constitutive and inducible expression of antioxidant response element (ARE)-dependent genes, nuclear factor erythroid 2-related factor 2 (Nrf2) plays a critical role in maintaining cellular redox homeostasis. Consistent with the properties of Nrf2-mediated antioxidant response, Nrf2-ARE activity is a direct indicator of oxidative stress and thus has been used to identify and characterize oxidative stressors and redox modulators. To screen and distinguish chemicals or environmental insults that affect the cellular antioxidant activity and/or induce oxidative stress, various in vitro cell models expressing distinct ARE reporters with high-throughput and high-content properties have been developed. These ARE-reporter systems are currently widely applied in drug discovery and safety assessment. In the present review, we provide an overview of the basic structures and applications of various ARE-reporter systems employed for discovering Nrf2-ARE modulators and characterizing oxidative stressors.

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.

Rutaecarpine prevents the malignant biological properties of breast cancer cells by the miR-149-3p/S100A4 axis

Background

Breast cancer (BC) is a frequent malignancy that endangers women's health, and its fatality rate ranks 1st among female malignancies. Research has shown that rutaecarpine (RUT), which is a Chinese herbal medicine, blocks the proliferation of cancer cells by a variety of molecular mechanisms. However, the possible effects and mechanism of RUT in the autophagy and angiogenesis of BC cells has not been clearly articulated.

Methods

MiR-149-3p and S100A4 expression levels were assessed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and the optimal concentration and time of RUT was confirmed by Cell Counting Kit-8 (CCK-8) assays of the BC cells. After treatment, changes in cell proliferation and the cell cycle were evaluated by CCK-8 assays, clone formation assays, and flow cytometry, and the levels of apoptosis, autophagy, and angiogenesis-related proteins were identified by Western blot. The targeted regulation of miR-149-3p on S100A4 was also examined by luciferase reporter assays.

Results

We found that RUT inhibited cell growth and upregulated miR-149-3p in MDA-MB-231 cells. In relation to the biological function activity, RUT attenuated proliferation and angiogenesis, and induced cell-cycle arrest and autophagy by miR-149-3p in the MDA-MB-231 cells. Additionally, miR-149-3p downregulated S100A4 by targeting binding to S100A4, and S100A4 was required for miR-149-3p to play a role in BC progression. We also discovered that an autophagy agonist (rapamycin) or an angiogenesis inhibitor (TNP-470) changed BC progression mediated by the RUT/miR-149-3p/S100A4 axis.

Conclusions

RUT blocks the malignant behaviors of BC cells through the miR-149-3p/S100A4 axis and thus alters autophagy and angiogenesis. Thus, the RUT-mediated miR-149-3p/S100A4 axis might be an underlying therapeutic agent and target for BC.

Polysaccharides from Garlic Protect against Liver Injury in DSS-Induced Inflammatory Bowel Disease of Mice via Suppressing Pyroptosis and Oxidative Damage

Inflammatory bowel disease (IBD), a widespread intestinal disease threatening human health, is commonly accompanied by secondary liver injury (SLI). Pyroptosis and oxidative stress act as an important role underlying the pathophysiology of SLI, during which a large number of proinflammatory cytokines and oxidative intermediates can be produced, thereby causing the liver severely damaged. Suppression of pyroptosis and oxidative damage can be considered one of the critical strategies for SLI therapy. Garlic, a natural food with eatable and medicinal functions, is widely used in people's daily life. There is no study about the alleviation of garlic against IBD accompanied with SLI. This study is aimed at investigating the efficacy of the polysaccharides from garlic (PSG) in treating IBD and SLI, as well as its pharmacological mechanism. The results showed that PSG significantly alleviated dextran sulfate sodium-induced IBD determined by evaluating the bodyweight loss, disease activity index, colon length, and colonic pathological examination of mice. PSG significantly reduced the colonic inflammation by reversing the levels of myeloperoxidase, diamine oxidase activity, iNOS, and COX2 and strengthened the intestinal barrier by increasing the expressions of ZO1, occludin, and MUC2 of IBD mice. Furthermore, PSG strongly alleviated SLI determined by assessing the liver morphological change, liver index, levels of ALT and AST, and liver pathological change of mice. Mechanically, PSG reduced the high levels of LPS, IL-1β, IL18, NLRP3, gasdermin D, caspase 1, ASC, TLR4, MyD88, NF-κB, phospho-NF-κB, while it increased IL-10 in the livers of mice, indicating that PSG alleviated SLI by suppressing inflammation and pyroptosis. Additionally, PSG significantly inhibited the oxidative damage in the liver tissues of SLI mice by reducing the levels of ROS, MDA, Keap-1, 8-OHDG, and phospho-H2AX and increasing the levels of GPX4, SOD2, HO1, NQO1, and Nrf2. These findings suggested that the garlic polysaccharides could be used to treat IBD accompanied with SLI in humans.

Traditional Chinese Medicine and Natural Products: Potential Approaches for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a rare, recurrent, and intractable inflammation obstruction of the stomach tract, usually accompanied by inflammation of cell proliferation and inflammation of the colon and carries a particular cause of inflammation. The clinical use of drugs in western countries affects IBD treatment, but various adverse effects and high prices limit their application. For these reasons, Traditional Chinese Medicine (TCM) is more advantageous in treating IBD. This paper reviews the mechanism and research status of TCM and natural products in IBD treatment by analyzing the relevant literature to provide a scientific and theoretical basis for IBD treatment.

The Protective Effect of Sulforaphane on Dextran Sulfate Sodium-Induced Colitis Depends on Gut Microbial and Nrf2-Related Mechanism

Sulforaphane (SFN), an isothiocyanate present in cruciferous vegetables such as broccoli and brussels sprouts, has a variety of biological functions. This study was undertaken to assess the potential efficacy of SFN in ameliorating dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice and to elucidate the underlying mechanisms. UC was induced in mice with administration of 2% DSS in drinking water for 7 days. Male C57BL/6 mice were treated with Mesalazine (50 and 100 mg/kg body weight) and various doses of SFN (2.5, 5, 10, and 20 mg/kg body weight). In DSS colitis mice, the hallmarks of disease observed as shortened colon lengths, increased disease activity index (DAI) scores and pathological damage, higher proinflammatory cytokines and decreased expression of tight junction proteins, were alleviated by SFN treatment. SFN also partially restored the perturbed gut microbiota composition and increased production of volatile fatty acids (especially caproic acid) induced by DSS administration. The heatmap correlation analysis indicated that Lactobacillus johnsonii, Bacteroides acidifaciens, unclassified Rikenellaceae RC9, and unclassified Bacteroides were significantly correlated with disease severity. Nuclear factor (erythroid-derived 2)-like 2 (Nrf2), Signal Transducer and Activator of Transcription 3 (STAT3), and Phase II enzyme UDP-glucuronosyltransferase (UGT) were involved in the protective effect of SFN against DSS-induced colitis. This study's findings suggest that SFN may serve as a therapeutic agent protecting against UC.

Adipose-Derived Mesenchymal Stem Cells Combined With Extracellular Vesicles May Improve Amyotrophic Lateral Sclerosis

The complexity of central nervous system diseases together with their intricate pathogenesis complicate the establishment of effective treatment strategies. Presently, the superiority of adipose-derived mesenchymal stem cells (ADSCs) on neuronal injuries has attracted significant attention. Similarly, extracellular vesicles (EVs) are potential interventional agents that could identify and treat nerve injuries. Herein, we reviewed the potential effects of ADSCs and EVs on amyotrophic lateral sclerosis (ALS) injured nerves, and expound on their practical application in the clinic setting. This article predominantly focused on the therapeutic role of ADSCs concerning the pathogenesis of ALS, the protective and reparative effects of EVs on nerve injury, as well as the impact following the combined usage of ADSCs and EVs in ALS.

Cold Exposure Induces Intestinal Barrier Damage and Endoplasmic Reticulum Stress in the Colon via the SIRT1/Nrf2 Signaling Pathway

Ambient air temperature is a key factor affecting human health. Long-term exposure to a cold environment can cause various diseases, while the impact on the intestine, the organ which has the largest contact area with the external environment, cannot be ignored. In this study, we investigated the effect of chronic cold exposure on the colon and its preliminary mechanism of action. Mice were exposed to 4°C for 3 hours a day for 10 days. We found that cold exposure damaged the morphology and structure of the colon, destroyed the tight junctions of the colonic epithelial tissue, and promoted inflammation of the colon. At the same time, cold exposure also activated the unfolded protein response (UPR) in the colon and promoted apoptosis in intestinal epithelial cells. Chronic cold exposure induced oxidative stress in vivo, but also significantly enhanced the response of the Nrf2 pathway that promotes an anti-oxidant effect. Furthermore, we demonstrated that chronic cold exposure promoted p65 acetylation to aggravate the inflammatory response by inhibiting SIRT1. Similar results were observed following SIRT1 knock-down by shRNA in Caco-2 cells treated with Thapsigargin (Tg). Knock-down of SIRT1 promoted nuclear localization of Nrf2, and increased the level of Nrf2 acetylation. Taken together, our study indicates that cold exposure may aggravate endoplasmic reticulum stress and damage epithelial tight junctions in the colon by inhibiting SIRT1, which promotes nuclear localization of Nrf2 and induces an anti-oxidant response to maintain intestinal homeostasis. These findings suggest that SIRT1 is a potential target for regulating intestinal health under cold exposure conditions.

Rutaecarpine ameliorates lipopolysaccharide‑induced BEAS‑2B cell injury through inhibition of endoplasmic reticulum stress via activation of the AMPK/SIRT1 signaling pathway

Rutaecarpine (RUT) is an alkaloid isolated from Tetradium ruticarpum, which has been reported to protect against several inflammatory diseases. However, to the best of our knowledge, the role of RUT in acute lung injury (ALI) and the specific molecular mechanism remain unknown. In the present study, an in vitro model of ALI was established in BEAS-2B cells by lipopolysaccharide (LPS) administration. Cell viability following RUT treatment with or without LPS stimulation was evaluated using a Cell Counting Kit-8 assay. The inflammatory response and oxidative stress were detected using ELISA kits and commercially available kits, respectively. TUNEL assay and western blotting were performed to assess cell apoptosis. The expression levels of endoplasmic reticulum (ER) stress-related proteins and AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) signaling pathway-related proteins were measured by western blotting. The results revealed that RUT markedly improved cell viability after LPS treatment in a dose-dependent manner. In addition, RUT inhibited the LPS-induced inflammatory response and oxidative stress in BEAS-2B cells, and suppressed the LPS-induced apoptosis of BEAS-2B cells. Mechanistically, RUT alleviated ER stress by inhibiting the production of CHOP, glucose-regulated protein-78, caspase-12 and activating transcription factor 6. Additionally, western blotting demonstrated that RUT activated the phosphorylation of AMPK and SIRT1, which indicated the involvement of the AMPK/SIRT1 signaling pathway in the protective effect of RUT against LPS-induced lung injury. In conclusion, these results demonstrated that RUT mitigated LPS-induced lung cell injury by inhibiting ER stress via the activation of the AMPK/SIRT1 signaling pathway.

Artemisia argyi extract alleviates inflammation in a DSS-induced colitis mouse model and enhances immunomodulatory effects in lymphoid tissues

Background

The incidence of inflammatory bowel disease (IBD), an inflammatory disorder of the gastrointestinal system has increased. IBD, characterized by aberrant immune responses against antigens, is thought to be caused by the invasion of enterobacteria. The pathogenesis of IBD is complicated, hence novel effective therapeutic agents are warranted. Therefore, this study evaluates the potential of Artemisia argyi, a medicinal herb, in alleviating IBD.

Methods

The effectiveness of the A. argyi ethanol extract was verified both in vitro and in vivo. Inflammation was induced in RAW 264.7 cells by 1 μg/mL of lipopolysaccharide (LPS) and by 3% dextran sodium sulfate (DSS) in a DSS-induced colitis mouse model. During the ten-day colitis induction, 200 mg/kg of A. argyi ethanol extract was orally administered to the treatment group. Levels of inflammation-related proteins and genes were analyzed in the colon, serum, and lymphoid tissues, i.e., Peyer’s patches (PPs) and spleen. The chemical constituent of the A. argyi ethanol extract was identified using an ultra-high performance liquid chromatography mass spectrometry (UPLC-MS/MS) analysis.

Results

A. argyi ethanol extract treatment ameliorated IBD symptoms and reduced the expression of inflammation-related proteins and genes in the colon and serum samples. Furthermore, A. argyi treatment induced the activation of anti-oxidative associated proteins, such as nuclear factor-erythroid factor 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1); and the treatment have also inhibited nuclear factor-κB (NF-κB), a central mediator of inflammatory responses. A. argyi enhanced the immunomodulatory effects in the PPs and spleen, which may stem from interleukin-10 (IL-10) upregulation. Chemical analysis identified a total of 28 chemical compounds, several of which have been reported to exert anti-inflammatory effects.

Conclusions

The effectiveness of the A. argyi ethanol extract in alleviating IBD was demonstrated; application of the extract successfully mitigated IBD symptoms, and enhanced immunomodulatory responses in lymphoid tissues. These findings suggest A. argyi as a promising herbal medicine for IBD treatment.

4-Octyl Itaconate Supplementation Relieves Soybean Diet-Induced Liver Inflammation and Glycolipid Metabolic Disorders by Activating the Nrf2-Pparγ Pathway in Juvenile Gibel Carp

Itaconate is a promising new candidate for anti-inflammatory and metabolic reprogramming, and 4-octyl itaconate (OI) is a cell-permeable itaconate derivative. To investigate the effect of OI in inflammatory response and glycolipid metabolism, we fed gibel carp with a 40% dietary soybean meal diet containing 0.1% OI (SBM + 0.1OI) or not (SBM) and compared these with fishmeal (FM) as reference. Compared with FM, dietary SBM decreased the growth performance, induced inflammation in the intestine and liver, and decreased the glucose utilization ability of the liver. However, 0.1% OI supplementation in SBM significantly increased the growth performance (from 20.11 ± 0.77 to 23.33 ± 0.45 g, P < 0.05), reduced inflammation in different organs through Nrf2 activation, and alleviated SBM-induced high plasma glucose (from 6.06 ± 0.23 to 4.37 ± 0.14 g, P < 0.05) and low crude body lipid (from 4.08 ± 0.17 to 4.91 ± 0.10 g, P < 0.05). Multi-omics revealed that OI had obvious effects on carbohydrate metabolism. OI regulates peroxisome proliferator-activated receptor gamma (ppar-γ), and its target genes (glut2 and gk) enhance liver glycolysis and lipid de novo lipogenesis, which are also dependent on Nrf2 activation. To conclude, dietary 0.1% OI can promote the growth of gibel carp and alleviate foodborne intestinal and hepatic inflammation and abnormal glycolipid metabolism by Nrf2-regulated Pparγ expression.

Ficus pandurata Hance Inhibits Ulcerative Colitis and Colitis-Associated Secondary Liver Damage of Mice by Enhancing Antioxidation Activity

Inflammatory bowel disease (IBD), a global disease threatening human health, is commonly accompanied by secondary liver damage (SLD) mediated by the gut-liver axis. Oxidative stress acts a critical role in the onset of IBD, during which excessive oxidation would destroy the tight junctions between intestinal cells, promote proinflammatory factors to penetrate, and thereby damage the intestinal mucosa. Ficus pandurata Hance (FPH) is widely used for daily health care in South China. Our previous study showed that FPH protected acute liver damage induced by alcohol. However, there is no study reporting FPH treating ulcerative colitis (UC). This study is designed to investigate whether FPH could inhibit UC and reveal its potential mechanism. The results showed that FPH significantly alleviated the UC disease symptoms including the body weight loss, disease activity index (DAI), stool consistency changing, rectal bleeding, and colon length loss of UC mice induced by dextran sulfate sodium (DSS) and reversed the influences of DSS on myeloperoxidase (MPO) and diamine oxidase activity (DAO). FPH suppressed UC via inhibiting the TLR4/MyD88/NF-κB pathway and strengthened the gut barrier of mice via increasing the expressions of ZO-1 and occludin and enhancing the colonic antioxidative stress property by increasing the levels of T-SOD and GSH-Px and the expressions of NRF2, HO-1, and NQO1 and reducing MDA level and Keap1, p22-phox, and NOX2 expressions. Furthermore, FPH significantly inhibited SLD related to colitis by reducing the abnormal levels of the liver index, ALT, AST, and cytokines including TNFα, LPS, LBP, sCD14, and IL-18 in the livers, as well as decreasing the protein expressions of NLRP3, TNFα, LBP, CD14, TLR4, MyD88, NF-κB, and p-NF-κB, suggesting that FPH alleviated UC-related SLD via suppressing inflammation mediated by inhibiting the TLR4/MyD88/NF-κB pathway. Our study firstly investigates the anticolitis pharmacological efficacy of FPH, suggesting that it can be enlarged to treat colitis and colitis-associated liver diseases in humans.

Isosteviol Sodium Exerts Anti-Colitic Effects on BALB/c Mice with Dextran Sodium Sulfate-Induced Colitis Through Metabolic Reprogramming and Immune Response Modulation

PURPOSE

Inflammatory bowel diseases (IBDs) are global health problems that are associated with immune regulation, but clinical IBDs treatment is currently inadequate. Effective preventive or therapeutic methods for immune disorders rely on controlling the function of immune cells. Isosteviol sodium (STV-Na) has antioxidant activity, but the therapeutic effect of STV-Na against IBD remain undocumented. Herein, we investigated the therapeutic effect of STV-Na in mice models with IBDs.

METHODS

Mice received 3.5% DSS for 7 days to establish IBD models. Intraperitoneal STV-Na was given 2 days before DSS and lasted for 9 days. Commercially available drugs used in treating IBDs (5-aminosalicylic acid, dexamethasone, and infliximab) were used as positive controls. Samples were collected 7 days after colitis induction. Histopathological score, biochemical parameters, molecular biology methods, and metabolomics were used for evaluating the therapeutic effect of STV-Na.

RESULTS

Our data revealed that STV-Na could significantly alleviate colon inflammation in mice with colitis. Specifically, STV-Na treatment improved body weight loss, increased colon length, decreased histology scores, and restored the hematological parameters of mice with colitis. The untargeted metabolomics analysis revealed that metabolic profiles were restored by STV-Na treatment. Furthermore, STV-Na therapy suppressed the number of CD68 macrophages and F4/80 cell infiltration. And STV-Na suppressed M1 and M2 macrophage numbers along with the mRNA expressions of proinflammatory cytokines. Moreover, STV-Na administration increased the number of regulatory T (Treg) cells while decreasing Th1/Th2/Th17 cell counts in the spleen. Additionally, STV-Na treatment restored intestinal barrier disruption in DSS-triggered colitis tissues by ameliorating the TJ proteins, increasing goblet cell proportions, and mucin protein production, and decreasing the permeability to FITC-dextran, which was accompanied by decreased plasma LPS and DAO contents.

CONCLUSION

These results indicate that STV-Na can ameliorate colitis by modulating immune responses along with metabolic reprogramming, and could therefore be a promising therapeutic strategy for IBDs.

Caffeic Acid Supplement Alleviates Colonic Inflammation and Oxidative Stress Potentially Through Improved Gut Microbiota Community in Mice

Caffeic acid (CA) is one of the major phenolic acids of coffee with multiple biological activities. Our previous study found that 500 mg/kg of chlorogenic acid (CGA) had the potential capacity of alleviating colonic inflammation. Moreover, CGA can be degraded into caffeic acid (CA) by the gut microbiota in the colon. Therefore, we hypothesize that CA can exert protective effects on colonic inflammation. To test the hypothesis, 251 mg/kg CA was supplemented to DSS-induced colitis mice. The results showed that CA treatment recovered DSS-induced disease activity index (DAI), colon length, and histopathology scores of colon tissue. Additionally, CA treatment significantly decreased pro-inflammatory cytokines and malondialdehyde (MDA) levels and increased the level of IL-10, total antioxidant capacity (T-AOC), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) in serum. qPCR results indicated that CA treatment dramatically downregulated mRNA expression of IL-1β, IL-6, and TNF-α as well as upregulated SOD1, GPX1, GPX2, CAT, and IL-10. In addition, CA supplementation significantly increased mRNA expression of Nrf-2, HO-1, and NQO1, which showed its antioxidant and anti-inflammatory capacities potentially by activating the Nrf-2/HO-1 pathway. Moreover, CA supplementation prevented gut barrier damage by enhancing Occludin gene expression. Furthermore, CA supplementation altered the gut microbiome composition by decreasing the relative abundance of Bacteroides and Turicibacter, and enhancing the relative abundance of Alistipes and Dubosiella. Meanwhile, CA supplementation increases the abundance of Dubosiella and Akkermansia. In conclusion, CA supplementation could effectively alleviate DSS-induced colitis by improving the defense against oxidative stress and inflammatory response.

Green Pea (Pisum sativum L.) Hull Polyphenol Extracts Ameliorate DSS-Induced Colitis through Keap1/Nrf2 Pathway and Gut Microbiota Modulation

As a processing by-product, green pea hull (GPH) was found to be rich in phenolic components in our previous studies. In this study, UHPLC-LTQ-OrbiTrap-MS (Ultra performance liquid chromatography-linear ion trap orbitrap tandem mass spectrometry) technique was used to quantify polyphenols, and DSS (sodium dextran sulfate)-induced colitis mouse model was established to explore the effect of GPH extracts on colitis. The results showed that quercetin and its derivatives, kaempferol trihexanside and catechin and its derivatives were the main phenolic substances in the extract, reaching 2836.57, 1482.00 and 1339.91 µg quercetin/g GPH extract, respectively; GPH extracts can improved inflammatory status, repaired colonic function, regulated inflammatory factors, and restored oxidative balance in mice. Further, GPH extracts can activate Keap1-Nrf2-ARE signaling pathway, regulate downstream antioxidant protease and gut microbiota by increasing F/B value and promoting the growth of Lactobacillaceae and Lachnospiraceae, and improve the level of SCFAs (short-chain fatty acids) to relieve DSS-induced colitis in mice. Therefore, GPH may be a promising dietary resource for the treatment of ulcerative colitis.

Natural-derived alkaloids exhibit great potential in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic nonspecific inflammatory disease of colon and rectum with unknown etiology, and the lesions are mainly confined to the mucosa and submucosa of large intestine. The main clinical features of UC include diarrhea, abdominal pain, bloody purulent stool and tenesmus, which seriously affect patients' quality of life. Most of UC patients would receive drug therapy with the exception of surgery for some severe cases. However, current drugs for the treatment of UC have certain limitations including difficulty of radical treatment, adverse reactions and drug resistance after long-term use and exorbitant price of some drugs. The research and development of new drugs for the treatment of UC is urgent, and natural alkaloids are an important source. This research paid close attention to the progress of natural alkaloids from diverse medicinal plants for treating UC in the last twenty years. The potential mechanisms for the natural alkaloids in the treatment of UC was closely related to its modulation of oxidative stress, immune response, intestinal flora and improvement of the gut barrier function. Remarkable effectiveness and safety of natural-derived alkaloids make them potential candidates of UC therapy.

St. John's Wort alleviates dextran sodium sulfate-induced colitis through pregnane X receptor-dependent NFκB antagonism

St. John's wort (SJW), from traditional herbs, activates the pregnane X receptor (PXR), a potential drug target for treating inflammatory bowel disease (IBD). However, how SJW alleviates dextran sodium sulfate (DSS)-induced experimental IBD by activating PXR is unknown. To test this, PXR-humanized, wild-type (WT) and Pxr-null mice, primary intestinal organoids cultures, and the luciferase reporter gene assays were employed. In vivo, a diet supplemented with SJW was found to activate intestinal PXR both in WT and PXR-humanized mice, but not in Pxr-null mice. SJW prevented DSS-induced IBD in PXR-humanized and WT mice, but not in Pxr-null mice. In vitro, hyperforin, a major component of SJW, activated PXR and suppressed tumor necrosis factor (TNF)α-induced nuclear factor (NF) κB translocation in primary intestinal organoids from PXR-humanized mice, but not Pxr-null mice. Luciferase reporter gene assays showed that hyperforin dose-dependently alleviated TNFα-induced NFκB transactivation by activating human PXR in Caco2 cells. Furthermore, SJW therapeutically attenuated DSS-induced IBD in PXR-humanized mice. These data indicate the therapeutic potential of SJW in alleviating DSS-induced IBD in vivo, and TNFα-induced NFκB activation in vitro, dependent on PXR activation, which may have clinical implications for using SJW as a herbal drug anti-IBD treatment.

Identification of evodiamine and rutecarpine as novel TMEM16A inhibitors and their inhibitory effects on peristalsis in isolated Guinea-pig ileum

The transmembrane member 16A (TMEM16A)-encoded Ca2+-activated Cl- channel (CaCC) is expressed in interstitial cells of Cajal (ICCs) and involved in the generation of the slow-wave currents of gastrointestinal (GI) smooth muscles. TMEM16A modulators have been shown to positively or negatively regulate the contraction of gastrointestinal smooth muscle. Therefore, targeting the pharmacological modulation of TMEM16A may represent a novel treatment approach for gastrointestinal dysfunctions such as constipation and diarrhoea. In this study, evodiamine and rutecarpine were extracted from the traditional Chinese medicine Evodia rutaecarpa and identified as novel TMEM16A inhibitors with comparable inhibitory effects. Their effects on intestinal peristalsis were examined. Whole-cell patch clamp results show that evodiamine and rutecarpine inhibited TMEM16A Cl- currents in CHO cells. The half-maximal inhibition values (IC50) of evodiamine and rutecarpine on TMEM16A Cl- currents were 11.8 ± 1.3 μΜ and 9.2 ± 0.4 μM, and the maximal effect values (Emax) were 95.8 ± 5.1% and 99.1 ± 1.6%, respectively. The Lys384, Thr385, and Met524 in TMEM16A are critical for evodiamine and rutecarpine's inhibitory effects. Further functional studies show that both evodiamine and rutecarpine can significantly suppress the peristalsis in isolated guinea-pig ileum. These findings demonstrate that evodiamine and rutecarpine are new TMEM16A inhibitors and support the regulation effect of TMEM16A modulators on gastrointestinal motility.

Rutaecarpine Increases Anticancer Drug Sensitivity in Drug-Resistant Cells through MARCH8-Dependent ABCB1 Degradation

The overexpression of adenosine triphosphate (ATP)-binding cassette (ABC) subfamily B member 1 (ABCB1; P-glycoprotein; MDR1) in some types of cancer cells is one of the mechanisms responsible for the development of multidrug resistance (MDR), which leads to the failure of chemotherapy. Therefore, it is important to inhibit the activity or reduce the expression level of ABCB1 to maintain an effective intracellular level of chemotherapeutic drugs. In this study, we found that rutaecarpine, a bioactive alkaloid isolated from Evodia Rutaecarpa, has the capacity to reverse ABCB1-mediated MDR. Our data indicated that the reversal effect of rutaecarpine was related to the attenuation of the protein level of ABCB1. Mechanistically, we demonstrated that ABCB1 is a newly discovered substrate of E3 ubiquitin ligase membrane-associated RING-CH 8 (MARCH8). MARCH8 can interact with ABCB1 and promote its ubiquitination and degradation. In short, rutaecarpine increased the degradation of ABCB1 protein by upregulating the protein level of MARCH8, thereby antagonizing ABCB1-mediated MDR. Notably, the treatment of rutaecarpine combined with other anticancer drugs exhibits a therapeutic effect on transplanted tumors. Therefore, our study provides a potential chemotherapeutic strategy of co-administrating rutaecarpine with other conventional chemotherapeutic agents to overcome MDR and improve therapeutic effect.

Mechanisms of Gegen Qinlian Pill to ameliorate irinotecan-induced diarrhea investigated by the combination of serum pharmacochemistry and network pharmacology

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine suggests the use of natural extracts and compounds is a promising strategy to prevent irinotecan (CPT-11)-induced gut toxicity and resulting diarrhea. Previous work from our lab indicated the protective effect of Gegen Qinlian decoction; given this, we further speculated that Gegen Qinlian Pill (GQP) would exhibit similar therapeutic effects. The effective material basis as well as potential mechanisms underlying the effect of GQP for the treatment of CPT-11-induced diarrhea have not been fully elucidated.

AIM OF THE STUDY

The application of natural extracts or compounds derived from Chinese medicine is deemed to a promising strategy to prevent irinotecan (CPT-11)-induced gut toxicity. The aim of this study was to investigated the beneficial effects of GQP on CPT-11-induced gut toxicity and further explored its anti-diarrheal mechanism.

METHODS

First, the beneficial effect of GQP in alleviating diarrhea in mice following CPT-11 administration was investigated. We also obtained the effective ingredients in GQP from murine serum samples using HPLC-Q-TOF-MS analysis. Based on these active components, we next established an interaction network linking "compound-target-pathway". Finally, a predicted mechanism of action was obtained using in vivo GQP validation based on Gene Ontology (GO) functional and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses.

RESULTS

A total of 19, GQP-derived chemical compounds were identified in murine serum samples. An interaction network linking "compound-target-pathway" was then established to illuminate the interaction between the components present in serum and their targets that mitigated diarrhea. These results indicated GQP exerted a curative effect on diarrhea and diarrhea-related diseases through different targets, which cumulatively regulated inflammation, oxidative stress, and proliferation processes.

CONCLUSION

Taken together, this study provides a feasible strategy to elucidate the effective constituents in traditional Chinese medicine formulations. More specifically, this work detailed the basic pharmacological effects and underlying mechanism behind GQP's effects in the treatment of CPT-11-induced gut toxicity.

Nrf2 Participates in M2 Polarization by Trichinella spiralis to Alleviate TNBS-Induced Colitis in Mice

Trichinella spiralis induced alternative activated macrophages (M2), leading to protect against Crohn's disease, known as Th1 -related inflammation, which enhances oxidative stress in the host. However, the relationship of oxidative stress and T. spiralis -mediated immune response is still unknown. In our study, we showed that nuclear factor erythroid 2-related factor-2 (Nrf2), a key transcription factor in antioxidant, participated in M2 polarization induced by T. spiralis muscle larval excretory/secretory (ES) products in vitro. ES -treated M2 were injected intravenously after TNBS challenge and we demonstrated that ES-M could alleviate the severity of the colitis in mice. Adoptive transfer of ES -treated M2 decreased the level of IFN-γ and increased the levels of IL-4 and IL-10 in vivo. However, the capacity of ES -treated Nrf2 KO macrophages to treat colitis was dramatically impaired. ES -treated Nrf2 KO macrophages was insufficient to result in the elevated levels of IL-4 and IL-10. These findings indicate that Nrf2 was required for M2 polarization induced by T. spiralis ES to alleviate colitis in mice.

Loss of QKI in macrophage aggravates inflammatory bowel disease through amplified ROS signaling and microbiota disproportion

Inflammatory bowel disease (IBD) is a refractory chronic inflammatory illness of the gastrointestinal (GI) tract. Macrophage exerts an important role in IBD development. QKI, as an RNA binding protein, was related with inflammatory responses in bacterial infections by regulating the polarization of macrophages. Therefore, we suspected that QKI-regulated macrophages have the potential to play a certain role in IBD and the underlying mechanism. Our results demonstrated that the mice with macrophage-specific deletion of QKI induced with dextran sodium sulfate (DSS) are more susceptible to IBD development, exhibited a severe leaky gut barrier phenotype and higher intense oxidative stress, which are rescued by treating with butylated hydroxyanisole (BHA), an agonist of NRF2. Mechanically, we observed that Keap1 mRNA in the nucleus was exported to the cytoplasm after LPS stimuli in parallel with QKI reductions, and the removal of QKI by shRNA facilitated Keap1 mRNA nuclear exporting and expression in cytoplasm, consequently NRF2 activation in nucleus was weakened, and led to the impaired antioxidant abilities. In addition, mice models of fecal microbiota transplant (FMT) and the co-culturing of mice epithelia cells with feces derived from the DSS-treated QKI-deficit mice revealed consistently aggravated colitis along with a severe oxidative stress; 16S sequencing analysis substantiated the altered compositions of commensal bacteria too. Overall, the current study represents the first effort to explore the anti-oxidant role of QKI in the intestinal macrophage via post-transcriptional regulation of Keap1 mRNA localization and the relevant NRF2 antioxidant signaling, and the disproportional changes in the microbiota were attributable to the mediation of pathogenic damage in the IBD development of QKI-deficit mice.

The dietary supplement Rhodiola crenulata extract alleviates dextran sulfate sodium-induced colitis in mice through anti-inflammation, mediating gut barrier integrity and reshaping the gut microbiome

Rhodiola species are edible medicinal plants, which have been traditionally used in both Asia and Europe as an adaptogen, a tonic, an anti-depressant and anti-inflammatory supplement. However, whether it presents a therapeutic effect on colitis or not remains unknown. The aim of this study is to investigate the protective effect of a Rhodiola crenulata extract (RCE) on mice with DSS-induced colitis. RCE significantly alleviated the pathological abnormalities in colitic mice, including the correspondingly increased colon length, ameliorated colonic injury and reduced pro-inflammatory factors. The protective effect was similar to that of the positive control, 5-aminosalicylic acid. The DSS-induced epithelial apoptosis and maintained intestinal barrier function were attenuated by RCE through the upregulation of the level of tight junction proteins such as ZO-1 and occludin. Notably, RCE prevented gut dysbiosis in colitic mice by restoring the microbial richness and diversity, and decreasing the abundance of Proteobacteria phylum and opportunistic pathogenic Parasutterella and Staphylococcus, as well as increasing the abundance of beneficial microbes in Lactobacillus and Bifidobacterium, which were closely correlated with its protective effect against colitis. Meanwhile, chemical characterization of RCE was performed by UPLC-HR-MS to explain its material basis. A total of 63 compounds were identified, while the content of two bioactive ingredients (salidroside, 1.81%; rosavin, 0.034%) was determined.

Rutaecarpine Ameliorates Ethanol-Induced Gastric Mucosal Injury in Mice by Modulating Genes Related to Inflammation, Oxidative Stress and Apoptosis

Background: Rutaecarpine (RUT), a major quinazolino carboline alkaloid compound from the dry unripe fruit Tetradium ruticarpum (A. Juss.) T. G. Hartley, has various pharmacological effects. The aim of this present study was to investigate the potential gastroprotective effect of rutaecarpine on ethanol-induced acute gastric mucosal injury in mice and associated molecular mechanisms, such as activating Nrf2 and Bcl-2 via PI3K/AKT signaling pathway and inhibiting NF-κB.

Methods: Gastric ulcer index and histopathology was carried out to determine the efficacy of RUT in gastric ulceration, and the content of SOD, GSH in serum and CAT, MDA, MPO, TNF-α, IL-6, IL-1β in tissue were measured by kits. Besides, in order to illustrate the potential inflammatory, oxidative, and apoptotic perturbations, the mRNA levels of NF-κB p65, PI3K, AKT, Nrf2, Nqo1, HO-1, Bcl-2 and Bax were analyzed. In addition, the protein expression of NF-κB p65 and Nrf2 in cytoplasm and nucleus, AKT, p-AKT, Bcl-2 Bax and Caspase 3 were analyzed for further verification. Finally, immunofluorescence analysis was performed to further verify nuclear translocation of NF-κB p65.

Results: Current data strongly demonstrated that RUT alleviated the gross gastric damage, ulcer index and the histopathology damage caused by ethanol. RUT inhibited the expression and nuclear translocation of NF-κB p65 and the expression of its downstream signals, such as TNF-α, IL-6, IL-1β and MPO. Immunofluorescence analysis also verifies the result. In the context of oxidative stress, RUT improved the antioxidant milieu by remarkably upregulating the expression Nqo1 and HO-1 with activating Nrf2, and could remarkably upregulate antioxidant SOD, GSH, CAT and downregulate levels of MDA. Additionally, RUT activate the expression of Bcl-2 and inhibited the expression of downstream signals Bax and Caspase 3 to promote gastric cellular survival. These were confirmed by RUT activation of the PI3K/AKT pathway manifested by enhanced expression of PI3K and promotion of AKT phosphorylation.

Conclusion: Taken together, these results strongly demonstrated that RUT exerted a gastroprotective effect against gastric mucosal injury induced by ethanol. The underlying mechanism might be associated with the improvement of anti-inflammatory, anti-oxidation and anti-apoptosis system.

α-Hydroxy acid as an aldehyde surrogate: metal-free synthesis of pyrrolo[1,2-a]quinoxalines, quinazolinones, and other N-heterocycles via decarboxylative oxidative annulation reaction

A metal-free and efficient procedure for the synthesis of pyrrolo[1,2-a]quinoxalines, quinazolinones, and indolo[1,2-a]quinoxaline has been developed. The key features of our method include the in situ generation of aldehyde from α-hydroxy acid in the presence of TBHP (tert-butyl hydrogen peroxide), and further condensation with various amines, followed by intramolecular cyclization and subsequent oxidation to afford the corresponding quinoxalines, quinazolinones derivatives in moderate to high yields.

Recent progress in Keap1-Nrf2 protein-protein interaction inhibitors

Therapeutic targeting the protein-protein interaction (PPI) of Nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and its main regulator, Kelch-like ECH-Associating protein 1 (Keap1) has been emerged as a feasible way to combat oxidative stress related diseases, due to the key role of Nrf2 in oxidative stress regulation. In recent years, many efforts have been made to develop potent Keap1-Nrf2 inhibitors with new chemical structures. Various molecules with diverse chemical structures have been reported and some compounds exhibit high potency. This review summarizes peptide and small molecule Keap1-Nrf2 inhibitors reported recently. We also highlight the pharmacological effects and discuss the possible therapeutic application of Keap1-Nrf2 inhibitors.

Tau accumulates in Crohn's disease gut

A sizeable body of evidence has recently emerged to suggest that gastrointestinal (GI) inflammation might be involved in the development of Parkinson's disease (PD). There is now strong epidemiological and genetical evidence linking PD to inflammatory bowel diseases and we recently demonstrated that the neuronal protein alpha-synuclein, which is critically involved in PD pathophysiology, is upregulated in inflamed segments of Crohn's colon. The microtubule associated protein tau is another neuronal protein critically involved in neurodegenerative disorders but, in contrast to alpha-synuclein, no data are available about its expression and phosphorylation patterns in inflammatory bowel diseases. Here, we examined the expression levels of tau isoforms, their phosphorylation profile and truncation in colon biopsy specimens from 16 Crohn's disease (CD) and 6 ulcerative colitis (UC) patients and compared them to samples from 16 controls. Additional experiments were performed in full thickness segments of colon of five CD and five control subjects, in primary cultures of rat enteric neurons and in nuclear factor erythroid 2-related factor (Nrf2) knockout mice. Our results show the upregulation of two main human tau isoforms in the enteric nervous system (ENS) in CD but not in UC. This upregulation was not transcriptionally regulated but instead likely resulted from a decrease in protein clearance via an Nrf2 pathway. Our findings, which provide the first detailed characterization of tau in CD, suggest that the key proteins involved in neurodegenerative disorders such as alpha-synuclein and tau, might also play a role in CD.

The Long Noncoding RNA ZFAS1 Potentiates the Development of Hepatocellular Carcinoma via the microRNA-624/MDK/ERK/JNK/P38 Signaling Pathway

Background

A long noncoding RNA (lncRNA), ZNFX1 antisense RNA 1 (ZFAS1), was increased in multiple cancers, including hepatocellular carcinoma (HCC), resulting in malignancy development and progression. However, the mechanisms involving the interaction between ZFAS1 and microRNA-624 (miRNA-624) remain largely unknown. Therefore, the goal of this study was to probe the functional role of ZFAS1 in the development of HCC and its underlying mechanism.

Methods

Firstly, differentially expressed lncRNAs in HCC tissues were screened out by microarray. Subsequently, the prognostic effect of ZFAS1 patients with HCC was analyzed by the Kaplan-Meier analysis and The Cancer Genome Atlas database. ZFAS1 regulation on miRNA-624 was determined after si-ZFAS1 and/or miRNA-624 inhibitor were transfected into HepG2 and SMMC7721 cell lines. Finally, the effects of ZFAS1 on the growth and metastasis of HCC were observed by in vivo tumorigenesis and metastasis tests.

Results

ZFAS1 was overexpressed in HCC tissues and cells and indicated worse prognosis and shorter survival in patients with HCC. Silencing of ZFAS1 inhibited the malignancy of HCC cells, but miR-624 inhibitor could partially reverse the repressive role of si-ZFAS1. Moreover, ZFAS1 induced the extracellular-regulated protein kinases/c-Jun N-terminal kinase (ERK/JNK)/P38 pathway by binding to midkine (MDK) through miR-624, thus promoting the occurrence of HCC.

Conclusion

Collectively, ZFAS1 depletion inhibited the occurrence of HCC by downregulating the MDK/ERK/JNK/P38 pathway through restoring miR-624 expression. Inhibition of ZFAS1 may act as an innovative target to suppress occurrence in HCC.