All-Trans Retinoic Acid Modulates TLR4/NF-κB Signaling Pathway Targeting TNF-α and Nitric Oxide Synthase 2 Expression in Colonic Mucosa during Ulcerative Colitis and Colitis Associated Cancer

Update of gut gas metabolism in ulcerative colitis

INTRODUCTION

Ulcerative colitis (UC) is a chronic, nonspecific inflammatory disease of the intestine. The intestinal microbiota is essential in the occurrence and development of UC. Gut gases are produced via bacterial fermentation or chemical interactions, which can reveal altered intestinal microbiota, abnormal cellular metabolism, and inflammation responses. Recent studies have demonstrated that UC patients have an altered gut gas metabolism.

AREAS COVERED

In this review, we integrate gut gas metabolism advances in UC and discuss intestinal gases' clinical values as new biomarkers or therapeutic targets for UC, providing the foundation for further research. Literature regarding gut gas metabolism and its significance in UC from inception to October 2023 was searched on the MEDLINE database and references from relevant articles were investigated.

EXPERT OPINION

Depending on their type, concentration, and volume, gut gases can induce or alleviate clinical symptoms and regulate intestinal motility, inflammatory responses, immune function, and oxidative stress, significantly impacting UC. Gut gases may function as new biomarkers and provide potential diagnostic or therapeutic targets for UC.

The protective effect of teprenone in TNBS-induced ulcerative colitis rats by modulating the gut microbiota and reducing inflammatory response

OBJECTIVE

Ulcerative colitis (UC), a chronic and refractory nonspecific inflammatory bowel disease, affects millions of patients worldwide and increases the risk of colorectal cancer. Teprenone is an acylic polyisoprenoid that exerts anti-inflammatory properties in rat models of peptic ulcer disease. This in vitro and in vivo study was designed to investigate the effects of teprenone on UC and to explore the underlying mechanisms.

METHODS

Human intestinal epithelial cells (Caco-2 cells) serve as the in vitro experimental model. Lipopolysaccharide (LPS, 1 μg/mL) was employed to stimulate the production of pro-inflammatory cytokines (interleukin [IL]-6, IL-1β, and tumor necrosis factor [TNF]-α), Toll-like receptor-4 (TLR4), MyD88 expression, and NF-κB activation. A trinitrobenzene sulfonic acid (TNBS)-induced chronic UC rat model was employed for the in vivo assay.

RESULTS

Pro-inflammatory cytokine stimulation by LPS in Caco-2 cells was inhibited by teprenone at 40 μg/mL through the TLR4/NF-κB signaling pathway. Teprenone attenuated TNBS-induced UC, decreased myeloperoxidase and malondialdehyde, induced TLR4 expression and NF-κB activation, and increased glutathione and zonula occludens-1 level in the rat colonic tissue. Moreover, Fusobacterium, Escherichia coli, Porphyromonas gingivalis elevation, and Mogibacterium timidum decline in UC rats were inhibited by teprenone.

CONCLUSION

Based on our results, the protective effects of teprenone for UC may be related to its ability to modulate the gut microbiota and reduce the inflammatory response.

Protective role of curcumin in disease progression from non-alcoholic fatty liver disease to hepatocellular carcinoma: a meta-analysis

Background: Pathological progression from non-alcoholic fatty liver disease (NAFLD) to liver fibrosis (LF) to hepatocellular carcinoma (HCC) is a common dynamic state in many patients. Curcumin, a dietary supplement derived from the turmeric family, is expected to specifically inhibit the development of this progression. However, there is a lack of convincing evidence. Methods: The studies published until June 2023 were searched in PubMed, Web of Science, Embase, and the Cochrane Library databases. The SYstematic Review Center for Laboratory animal Experimentation (SYRCLE) approach was used to evaluate the certainty of evidence. StataSE (version 15.1) and Origin 2021 software programs were used to analyze the critical indicators. Results: Fifty-two studies involving 792 animals were included, and three disease models were reported. Curcumin demonstrates a significant improvement in key indicators across the stages of NAFLD, liver fibrosis, and HCC. We conducted a detailed analysis of common inflammatory markers IL-1β, IL-6, and TNF-α, which traverse the entire disease process. The research results reveal that curcumin effectively hinders disease progression at each stage by suppressing inflammation. Curcumin exerted hepatoprotective effects in the dose range from 100 to 400 mg/kg and treatment duration from 4 to 10 weeks. The mechanistic analysis reveals that curcumin primarily exerts its hepatoprotective effects by modulating multiple signaling pathways, including TLR4/NF-κB, Keap1/Nrf2, Bax/Bcl-2/Caspase 3, and TGF-β/Smad3. Conclusion: In summary, curcumin has shown promising therapeutic effects during the overall progression of NAFLD-LF-HCC. It inhibited the pathological progression by synergistic mechanisms related to multiple pathways, including anti-inflammatory, antioxidant, and apoptosis regulation.

Overcoming cancer risk in inflammatory bowel disease: new insights into preventive strategies and pathogenesis mechanisms including interactions of immune cells, cancer signaling pathways, and gut microbiota

Inflammatory bowel disease (IBD), characterized primarily by gastrointestinal inflammation, predominantly manifests as Crohn's disease (CD) and ulcerative colitis (UC). It is acknowledged that Inflammation plays a significant role in cancer development and patients with IBD have an increased risk of various cancers. The progression from inflammation to carcinogenesis in IBD is a result of the interplay between immune cells, gut microbiota, and carcinogenic signaling pathways in epithelial cells. Long-term chronic inflammation can lead to the accumulation of mutations in epithelial cells and the abnormal activation of carcinogenic signaling pathways. Furthermore, Immune cells play a pivotal role in both the acute and chronic phases of IBD, contributing to the transformation from inflammation to tumorigenesis. And patients with IBD frequently exhibit dysbiosis of the intestinal microbiome. Disruption of the gut microbiota and subsequent immune dysregulation are central to the pathogenesis of both IBD and colitis associated colorectal cancer (CAC). The proactive management of inflammation combined with regular endoscopic and tumor screenings represents the most direct and effective strategy to prevent the IBD-associated cancer.

Gastrodin Attenuates Colitis and Prevents Tumorigenesis in Mice by Interrupting TLR4/MD2/NF-κB Signaling Transduction

INTRODUCTION

Chronic inflammation is one of the causative factors for tumorigenesis. Gastrodin is a main active ingredient isolated from Gastrodia elata Blume, a famous medicinal herb with a long edible history.

AIM

This study aimed to explore the effects of gastrodin on colitis-associated carcinogenesis (CRC) in mice and to elucidate its potential molecular mechanisms.

METHODS

Balb/c mice were induced with azoxymethane (AOM) and dextran sulfate sodium (DSS) for 12 weeks. Gastrodin (50 mg/kg) was administered via oral gavage three times per week until the end of the experiment. Disease indexes, including body weight, bloody diarrhea, colon length, histopathological score, and tumor size, were measured. Tumor cell proliferation was evaluated by BrdU incorporation assay and tumor cell cytotoxicity was assessed by cell counting kit (CCK-8). The expression levels of toll-like receptor 4 (TLR4)/nuclear factor kappa-B (NF-κB) signaling molecules, NF-κB luciferase, and pro-inflammatory cytokines were determined by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), immunoblotting, immunohistochemistry (IHC), enzyme-linked immunosorbent assay (ELISA), or reporter gene assays. The binding affinity between gastrodin and myeloid differentiation protein-2 (MD2) was analyzed by molecular docking and cellular thermal shift assay (CETSA).

RESULTS

Gastrodin administration was demonstrated to mitigate various CRC-related symptoms in mice, including weight loss, diarrhea, and tissue abnormalities. Notably, gastrodin suppressed tumor cell growth during colitis- associated tumorigenesis, resulting in fewer and smaller adenomas in the colon. Unlike irinotecan, a broadspectrum antitumor drug, gastrodin did not exhibit apparent cytotoxicity in various colorectal adenocarcinoma cell lines. Additionally, gastrodin downregulated TLR4/NF-κB signaling molecules and pro-inflammatory mediators in mice and macrophages. Molecular docking and CETSA experiments suggested that gastrodin binds to the MD2 protein, potentially interfering with the recognition of lipopolysaccharide (LPS) by TLR4, leading to NF-κB pathway inhibition.

CONCLUSION

This study provides evidence for the first time that gastrodin attenuated colitis and prevented colitisrelated carcinogenesis in mice, at least partially, by diminishing tumor-promoting cytokines through the interruption of TLR4/MD2/NF-κB signaling transduction.

Phytochemical analysis of Origanum majorana L. extract and investigation of its antioxidant, anti-inflammatory and immunomodulatory effects against experimentally induced colitis downregulating Th17 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Origanum majorana L. is a member of the Lamiaceae family and is commonly used in Egyptian cuisine as a seasoning and flavor enhancer. It is also recognized as a well-known traditional medicine in Egypt and is widely used for treating abdominal colic due to its antispasmodic properties. However, the protective effects of Origanum majorana L. against ulcerative colitis and its underlying mechanisms remain unclear.

AIM OF THE STUDY

This study aimed to identify the biologically active components present in methanol extracts of Origanum majorana L. using gas chromatography/mass spectrometry (GC/MS). Additionally, it aimed to investigate the therapeutic effects of these extracts on acetic acid-induced ulcerative colitis and elucidate the potential mechanisms involved.

MATERIALS AND METHODS

We conducted a GC-MS analysis of the methanolic extract obtained from Origanum majorana L. Thirty-two male rats were included in the study and divided into four experimental groups, with eight rats in each group: sham, UC, UC + O. majorana, and UC sulfasalazine. After euthanizing the rats, colon tissue samples were collected for gross and microscopic examinations, assessment of oxidative stress, and molecular evaluation. GC-MS analysis identified 15 components in the extracts. Pretreatment with O. majorana L. extract and sulfasalazine significantly improved the disease activity index (DAI) and resulted in notable improvements in macroscopic and microscopic colon findings. Additionally, both treatments demonstrated preventive effects against colonic oxidative damage by reducing the levels of malondialdehyde (MDA) and increasing the levels of the antioxidant systems superoxide dismutase (SOD), catalase (CAT), and glutathione (GSH), which operate through the Nrf2/HO-1 signaling pathway. Moreover, these treatments downregulated the colonic inflammatory cascade by inhibiting NFκB, TNFα, IL-1β, IL6, IL23, IL17, COX-2, and iNOS, subsequently leading to downregulation of the JAK2/STAT3 signaling pathway and a decrease in the Th17 cell response. Furthermore, a reduction in the number of apoptotic epithelial cells that expressed caspase-3 was observed.

CONCLUSION

pretreatment with O. majorana L. extract significantly ameliorated acetic acid-induced ulcerative colitis. This effect could be attributed to the protective, antioxidant, anti-inflammatory, and anti-apoptotic properties of the extract.

Tryptophan alleviates intestinal damage through regulating necroptosis and TLR4/NOD signaling pathways in pigs after lipopolysaccharide challenge

This study aimed to test the hypothesis that necroptosis, toll-like receptor 4 (TLR4)/nucleotide-binding oligomerization domain (NOD) signaling pathway in the jejunum of lipopolysaccharide (LPS)-challenged piglets are involved in the alleviation of intestinal injury and inflammation by tryptophan supplementation. Tryptophan supplementation has improved intestinal morphology. Also, tryptophan has been found to increase the mRNA and protein expression of tight junction proteins and decrease the expression of pro-inflammatory cytokines. Dietary tryptophan decreased the mRNA expression of heat shock protein 70, TLR4, NOD1, NOD2, myeloid differentiation primary response gene 88, interleukin 1 receptor-associated kinase 1, TNF receptor-associated factor 6, receptor-interacting serine/threonine-protein kinase 2-like, nuclear factor-kappaB transcription factor P65 in the jejunum of piglets. Tryptophan alleviated LPS-induced necroptosis and decreased the mRNA expression of mixed lineage kinase domain-like, receptor-interacting serine/threonine kinase 1, receptor-interacting serine/threonine-protein kinase 3-like, Fas (TNFRSF6)-associated via death domain, PGAM family member 5. Collectively, our results suggest that tryptophan supplementation helps in the attenuation of intestinal injury and inflammation by alleviating necroptosis and TLR4/NOD in lipopolysaccharide-challenged pigs.

Gut Microbiota, Inflammatory Bowel Disease, and Cancer: The Role of Guardians of Innate Immunity

Inflammatory bowel diseases (IBDs) are characterized by a persistent low-grade inflammation that leads to an increased risk of colorectal cancer (CRC) development. Several factors are implicated in this pathogenetic pathway, such as innate and adaptive immunity, gut microbiota, environment, and xenobiotics. At the gut mucosa level, a complex interplay between the immune system and gut microbiota occurs; a disequilibrium between these two factors leads to an alteration in the gut permeability, called 'leaky gut'. Subsequently, an activation of several inflammatory pathways and an alteration of gut microbiota composition with a proliferation of pro-inflammatory bacteria, known as 'pathobionts', take place, leading to a further increase in inflammation. This narrative review provides an overview on the principal Pattern Recognition Receptors (PRRs), including Toll-like receptors (TLRs) and NOD-like receptors (NLRs), focusing on their recognition mechanisms, signaling pathways, and contributions to immune responses. We also report the genetic polymorphisms of TLRs and dysregulation of NLR signaling pathways that can influence immune regulation and contribute to the development and progression of inflammatory disease and cancer.

The Contribution of Hippocampal All-Trans Retinoic Acid (ATRA) Deficiency to Alzheimer's Disease: A Narrative Overview of ATRA-Dependent Gene Expression in Post-Mortem Hippocampal Tissue

There is accumulating evidence that vitamin A (VA) deficiency contributes to the pathogenesis and progression of Alzheimer's disease (AD). All-trans retinoic acid (ATRA), a metabolite of VA in the brain, serves distinct roles in the human hippocampus. Agonists of retinoic acid receptors (RAR), including ATRA, promote activation of the non-amyloidogenic pathway by enhancing expression of α-secretases, providing a mechanistic basis for delaying/preventing amyloid beta (Aβ) toxicity. However, whether ATRA is actually deficient in the hippocampi of patients with AD is not clear. Here, using a publicly available human transcriptomic dataset, we evaluated the extent to which ATRA-sensitive genes are dysregulated in hippocampal tissue from post-mortem AD brains, relative to age-matched controls. Consistent with ATRA deficiency, we found significant dysregulation of many ATRA-sensitive genes and significant upregulation of RAR co-repressors, supporting the idea of transcriptional repression of ATRA-mediated signaling. Consistent with oxidative stress and neuroinflammation, Nrf2 and NfkB transcripts were upregulated, respectively. Interestingly, transcriptional targets of Nrf2 were not upregulated, accompanied by upregulation of several histone deacetylases. Overall, our investigation of ATRA-sensitive genes in the human hippocampus bolsters the scientific premise of ATRA depletion in AD and that epigenetic factors should be considered and addressed as part of VA supplementation.

Inhibitory effects of Clostridium butyricum culture and supernatant on inflammatory colorectal cancer in mice

Clostridium butyricum (CB) is a spore-forming, gram-positive and obligate anaerobic rod bacterium. CB can modulate the composition of the gut microbiome and promote the growth of beneficial microbes in the intestine by generating short-chain fatty acids (SCFAs), which in turn protect against colitis and prevents the formation of inflammatory-associated colorectal cancer (CRC) by ameliorating colon inflammatory processes. Yet, it remains unclear whether the culture and supernatant of CB could directly influence inflammatory CRC in mice. In this study, azoxymethane (AOM)+dextran sodium sulphate (DSS) was used to induce CRC model in C57BL/6 mice. Next, the serum levels of inflammatory cytokines, including interleukin-6 (IL-6), interleukin-10 (IL-10), and cytokines TNF-α, were measured and the pathohistological examination of the large intestine was performed. Both CB culture and supernatant were found to have anti-inflammatory properties. Subsequently, Western blot and Real-Time Quantitative PCR (RT-qPCR) revealed that CB and supernatant regulate the NF-κB/p65 pathway to inhibit the development and progression of inflammatory CRC in AOM+DSS-treated mice, which could be due to the high levels of butyric acid in the supernatant.

Nitric Oxide, Neutrophil/Lymphocyte, and Platelet/Lymphocyte Ratios as Promising Inflammatory Biomarkers in Complicated Crohn's Disease: Outcomes of Corticosteroids and Anti-TNF-α Therapies

Crohn's disease (CD) is a relapsing-remitting inflammatory bowel disease with a progressive course. The aim of our study was to evaluate the relationship between nitric oxide (NO), pro-inflammatory cytokines, and blood count-based ratios in patients with complicated Crohn's disease as well as the outcome of corticosteroid or anti-TNF-α therapy. In this context, we evaluated the NLR as the ratio of neutrophils count to lymphocytes count, PLR as the ratio of platelets count to lymphocytes count, and MLR as the ratio of monocytes count to lymphocytes count in patients and controls. Furthermore, we assessed NO production by the Griess method in plasma along with iNOS and NF-κB expression by immunofluorescence method in intestinal tissues of patients and controls. In the same way, we evaluated plasma TNF-α, IL-17A, and IL-10 levels using ELISA. Our results indicate that blood count-based ratios NLR, PLR, and MLR were significantly higher in patients compared to controls. In addition, increased systemic levels of NO, TNF-α, and IL-17A and colonic expression of iNOS and NF-κB were observed in the same patients. Interestingly, the high ratio of NLR and MLR as well as NO production were significantly decreased in treated patients. Collectively, our findings suggest that nitric oxide as well as the blood count-based ratios (NLR, PLR, MLR) could constitute useful biomarkers in complicated Crohn's disease, predicting the response to treatments.

Yiyi Fuzi Baijiang Powder Alleviates Dextran Sulfate Sodium-Induced Ulcerative Colitis in Rats via Inhibiting the TLR4/NF-κB/NLRP3 Inflammasome Signaling Pathway to Repair the Intestinal Epithelial Barrier, and Modulating Intestinal Microbiota

Ulcerative colitis (UC) is a chronic non-specific inflammatory disease of the intestine, which is prone to recurrence and difficult to cure. Yiyi Fuzi Baijiang powder (YFBP), as a classic Chinese herbal formula, is commonly used in the clinical treatment of UC. However, its potential mechanism remains unclear. In this study, we investigated the mechanism by which YFBP exerts a therapeutic effect against UC. Firstly, we used network pharmacology to screen the active ingredients and potential targets of YFBP and constructed a "drug-ingredient-target" network. Based on bioinformatics, we searched for differentially expressed genes (DEGs) associated with UC and obtained common targets. The core targets of YFBP in the treatment of UC were identified using a protein-protein interaction (PPI) network, and molecular docking techniques were used to evaluate the binding energies of the core targets and corresponding ingredients. Enrichment analysis by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that YFBP exerted therapeutic effects by regulating multiple inflammatory pathways including TLR4, NF-κB, and TNF. Secondly, an experimental study was carried out in vivo for verification. Our results demonstrated that YFBP could effectively improve the symptoms and intestinal pathological of UC rats. Further study showed that YFBP could significantly downregulate the expressions of TLR4 and p-NF-κB p65 in UC rats, inhibit the activation of NLRP3 inflammasome, reduce the levels of IL-1β and TNF-α, and then upregulate the expressions of tight junction proteins in intestinal epithelial cells. In addition, YFBP could improve the intestinal microbial community. In conclusion, our study revealed that YFBP had a good therapeutic effect on UC, and its mechanism might be related to the inhibition of the TLR4/NF-κB/NLRP3 inflammasome signaling pathway to repair intestinal epithelial barrier and the modulation of intestinal microbiota.

Effect of Diacerein on HOTAIR/IL-6/STAT3, Wnt/β-Catenin and TLR-4/NF-κB/TNF-α axes in colon carcinogenesis

Colorectal cancer (CRC) is a common malignancy with high mortality and poor prognosis. Diacerein (DIA) is an anti-inflammatory used for treatment of osteoarthritis. We delineated some underlying molecular mechanisms of DIA's anti-carcinogenic effect in CRC using in vivo and in vitro models. Human Caco-2 cells were treated with DIA followed by MTT and Annexin V assays and CRC was experimentally induced using 1,2-dimethylhydrazine. DIA (50 mg/kg/day, orally) was administrated for 8 weeks. The MTT assay confirmed cytotoxic effect of DIA in vitro and Annexin V confirmed its apoptotic effect. DIA resulted in regression of tumour lesions with reduced colonic TLR4, NF-κB and TNF-α protein levels and down-regulated VEGF expression, confirming anti-angiogenic impact. DIA triggered caspase-3 expression and regulated Wnt/β-Catenin pathway, by apparently interrupting the IL-6/STAT3/ lncRNA HOTAIR axis. In conclusion, DIA disrupted IL-6/STAT3/ lncRNA HOTAIR axis which could offer an effective therapeutic strategy for the management of CRC.

Colorectal Cancer in Ulcerative Colitis: Mechanisms, Surveillance and Chemoprevention

Patients with ulcerative colitis (UC) are at a two- to three-fold increased risk of developing colorectal cancer (CRC) than the general population based on population-based data. UC-CRC has generated a series of clinical problems, which are reflected in its worse prognosis and higher mortality than sporadic CRC. Chronic inflammation is a significant contributor to the development of UC-CRC, so comprehending the relationship between the proinflammatory factors and epithelial cells together with downstream signaling pathways is the core to elucidate the mechanisms involved in developing of CRC. Clinical studies have shown the importance of early prevention, detection and management of CRC in patients with UC, and colonoscopic surveillance at regular intervals with multiple biopsies is considered the most effective way. The use of endoscopy with targeted biopsies of visible lesions has been supported in most populations. In contrast, random biopsies in patients with high-risk characteristics have been suggested during surveillance. Some of the agents used to treat UC are chemopreventive, the effects of which will be examined in cancers in UC in a population-based setting. In this review, we outline the current state of potential risk factors and chemopreventive recommendations in UC-CRC, with a specific focus on the proinflammatory mechanisms in promoting CRC and evidence for personalized surveillance.

Vitamin–Microbiota Crosstalk in Intestinal Inflammation and Carcinogenesis

Inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC) are common diseases of the digestive system. Vitamin deficiencies and gut microbiota dysbiosis have a close relationship with the risk, development, and progression of IBD and CAC. There is a strong link between vitamins and the gut microbiome. Vitamins are extremely crucial for maintaining a healthy gut microbiota, promoting growth and development, metabolism, and innate immunity. Gut microbiota can not only influence the transport process of vitamins, but also produce vitamins to compensate for insufficient food intake. Emerging evidence suggests that oral vitamin supplementation can reduce inflammation levels and improve disease prognosis. In addition, improving the diet structure and consuming foods rich in vitamins not only help to improve the vitamin deficiency, but also help to reduce the risk of IBD. Fecal microbiota transplantation (FMT) and the application of vitamin-producing probiotics can better assist in the treatment of intestinal diseases. In this review, we discuss the interaction and therapeutic roles of vitamins and gut microbiota in IBD and CAC. We also summarize the methods of treating IBD and CAC by modulating vitamins. This may highlight strategies to target gut-microbiota-dependent alterations in vitamin metabolism in the context of IBD and CAC therapy.

Melatonin mediated inhibition of EZH2-NOS2 crosstalk attenuates inflammatory bowel disease in preclinical in vitro and in vivo models

AIMS

Inflammatory Bowel Disease is characterised by abdominal pain, diarrhoea, rectal bleeding and weight loss. Sometimes it may leads to severe health complications resulting in death of an individual. Current research efforts to highlight the role of melatonin in regulating EZH2, a master epigenetic regulator and its beneficiary effect in case of IBD management.

MATERIAL METHODS

Murine macrophages (RAW 264.7) were treated with lipopolysaccharides (LPS) to activate them for generating inflammatory response to investigate efficacy of melatonin in-vitro models. Similarly, for developing in vivo models, Dextran sodium sulphate (36-50 kDa) was used. Evaluations of anti-inflammatory activities were carried out by nitrite assay, western blotting, q-PCR, immunofluorescence, and histological studies.

KEY FINDINGS

Reduction of epigenetic target, EZH2 by melatonin significantly improves the clinical symptoms of dextran sodium sulphate induced colitis and may be implicated as a potential therapeutic target in IBD management. The present study evaluates the efficacy of melatonin by epigenetic regulation in IBD models. Down regulation of EZH2 by melatonin reduced the chemical induced inflammatory insults in in vitro and in vivo models. Exploration of molecular pathways has revealed interlink of EZH2 and NOS2, a hallmark of inflammation. Molecular mechanistic action of melatonin is attributed to inhibition of the expression and physical interaction of EZH2 and NOS2.

SIGNIFICANCE

Our study highlights melatonin therapeutic effect via attenuating interaction between EZH2 and NOS2 which is beneficial in managing IBD treatment.

Gasotransmitters in the tumor microenvironment: Impacts on cancer chemotherapy (Review)

Nitric oxide, carbon monoxide and hydrogen sulfide are three endogenous gasotransmitters that serve a role in regulating normal and pathological cellular activities. They can stimulate or inhibit cancer cell proliferation and invasion, as well as interfere with cancer cell responses to drug treatments. Understanding the molecular pathways governing the interactions between these gases and the tumor microenvironment can be utilized for the identification of a novel technique to disrupt cancer cell interactions and may contribute to the conception of effective and safe cancer therapy strategies. The present review discusses the effects of these gases in modulating the action of chemotherapies, as well as prospective pharmacological and therapeutic interfering approaches. A deeper knowledge of the mechanisms that underpin the cellular and pharmacological effects, as well as interactions, of each of the three gases could pave the way for therapeutic treatments and translational research.

NF-kB pathway is involved in microscopic colitis pathogenesis

OBJECTIVE

To investigate the potential inflammatory pathways involved in the development of microscopic colitis (MC).

METHODS

This prospective study analysed human intestinal tissue that was collected and classified as healthy controls (HC), microscopic colitis (MC) and ulcerative colitis (UC). An RT² Profiler PCR Array for human inflammatory response and autoimmunity was used to evaluate the expression of 84 specific genes related to the inflammatory and autoimmunity pathways. Data were validated by means of real-time polymerase chain reaction on an independent group of MC intestinal tissue samples.

RESULTS

This study measured the expression of inflammatory genes in HC (n = 10), in patients with MC (n = 8) and in patients with active UC (n = 10). Of the 84 genes included in the array, the expression of the C-C motif chemokine ligand 19, C-C motif chemokine ligand 21, lymphotoxin beta and complement C3 genes that are involved in the non-canonical nuclear transcription factor kappa B (NF-kB) pathway was increased by 2.96, 6.05, 5.96 and 5.93 times in MC compared with HC, respectively. These results were confirmed by real-time polymerase chain reaction.

CONCLUSIONS

The findings suggest that an impairment of the non-canonical NF-kB pathway is involved in the development of MC.

Yiyi Fuzi Baijiang Decoction Alleviates Ulcerative Colitis Partly by Regulating TLR4-Mediated PI3K/Akt and NF-κB Pathways

Yiyi Fuzi Baijiang Decoction (YFBD), an ancient prescription developed by the ancient Chinese physician, Zhang Zhongjing, has shown remarkable effects in treating ulcerative colitis (UC). However, there are few studies on its mechanism. This study was designed to explore the potential mechanism of YFBD in treating UC. The principal ingredients of YFBD were analyzed using high-performance liquid chromatography (HPLC). Dextran sulfate sodium- (DSS-) induced mice and lipopolysaccharide- (LPS-) stimulated RAW264.7 cells were used in the study. The body weight and disease activity index (DAI) of mice were recorded and analyzed for 10 days. After sacrifice, the colonic tissues were harvested. The colon length was measured, and the histopathological changes were observed by hematoxylin and eosin staining. The levels of inflammatory cytokines in mice colons and RAW246.7 cells were determined by real-time quantitative PCR and immunofluorescence. The effects of YFBD on the TLR4-mediated PI3K/Akt and NF-κB pathways were determined by western blot analysis. HPLC identified five compounds in YFBD: chlorogenic acid, caffeic acid, benzoylmesaconine, benzoyl aconitine, and quercetin. YFBD alleviated weight loss, colon shortening, and colonic histopathological lesion in mice. Meanwhile, it decreased the DAI and histological score of mice with UC. In addition, YFBD remarkably decreased the levels of interleukin- (IL-) 6, IL-1β, and tumor necrosis factor (TNF)-α in the colons of DSS-induced mice and LPS-stimulated RAW246.7 cells. Furthermore, the expression of key proteins in TLR4-mediated PI3K/Akt and NF-κB pathways significantly decreased with YFBD treatment. In conclusion, YFBD had protective effects on mice with UC, which was in part related to its anti-inflammatory effects and downregulation of TLR4-mediated PI3K/Akt and NF-κB pathways.

PRKAR2A-derived circular RNAs promote the malignant transformation of colitis and distinguish patients with colitis-associated colorectal cancer

BACKGROUND

Emerging studies have proved that colonic inflammation caused by refractory inflammatory bowel disease (IBD) can initiate the colitis-associated cancer (CAC), but the transition from inflammation to carcinoma is still largely unknown.

METHODS

In this study, mouse colitis and CAC models were established, and the RNA-seq by circRNA microarray was employed to identify the differentially expressed circRNAs and mRNAs in different comparisons (DSS vs. NC and AOM/DSS vs. DSS). The bioinformatics analyses were used to search the common characteristics in mouse colitis and CAC.

RESULTS

The K-means clustering algorithm packaged these differential expressed circRNAs into subgroup analysis, and the data strongly implied that mmu_circ_0001109 closely correlated to the pro-inflammatory signals, while mmu_circ_0001845 was significantly associated with the Wnt signalling pathway. Our subsequent data in vivo and in vitro confirmed that mmu_circ_0001109 could exacerbate the colitis by up-regulating the Jak-STAT3 and NF-kappa B signalling pathways, and mmu_circ_0001845 promoted the CAC transformation through the Wnt signalling pathway. By RNA blasting between mice and humans, the human RTEL1- and PRKAR2A-derived circRNAs, which might be considered as homeotic circRNAs of mmu_circ_0001109 and mmu_circ_0001845, respectively, were identified. The clinical data revealed that RTEL1-derived circRNAs had no clinical significance in human IBD and CAC. However, three PRKAR2A-derived circRNAs, which had the high RNA similarities to mmu_circ_0001845, were remarkably up-regulated in CAC tissue samples and promoted the transition from colitis to CAC.

CONCLUSIONS

Our results suggested that these human PRKAR2A-derived circRNAs could be novel candidates for distinguishing CAC patients and predicted the prognosis of CAC.

All-Trans Retinoic Acid Attenuates Transmissible Gastroenteritis Virus-Induced Inflammation in IPEC-J2 Cells via Suppressing the RLRs/NF-κB Signaling Pathway

Transmissible gastroenteritis virus (TGEV) infection can cause transmissible gastroenteritis (TGE), especially in suckling piglets, resulting in a significant economic loss for the global pig industry. The pathogenesis of TGEV infection is closely related to intestinal inflammation. All-trans retinoic acid (ATRA) has anti-inflammatory activity and immunomodulatory properties, but it is unclear whether ATRA can attenuate the inflammatory response induced by TGEV. This study aimed to investigate the protective effect of ATRA on TGEV-induced inflammatory injury in intestinal porcine epithelial cells (IPEC-J2) and to explore the underlying molecular mechanism. The results showed that TGEV infection triggered inflammatory response and damaged epithelial barrier integrity in IPEC-J2 cells. However, ATRA attenuated TGEV-induced inflammatory response by inhibiting the release of pro-inflammatory cytokines, including IL-1β, IL-6, IL-8 and TNF-α. ATRA also significantly reversed the reduction of ZO-1 and Occludin protein levels induced by TGEV infection and maintained epithelial barrier integrity. Moreover, ATRA treatment significantly prevented the upregulation of IкBα and NF-κB p65 phosphorylation levels and the nuclear translocation of NF-кB p65 induced by TGEV. On the other hand, treatment of TGEV-infected IPEC-J2 cells with the NF-κB inhibitors (BAY11-7082) significantly decreased the levels of inflammatory cytokines. Furthermore, ATRA treatment significantly downregulated the mRNA abundance and protein levels of TLR3, TLR7, RIG-I and MDA5, and downregulated their downstream signaling molecules TRIF, TRAF6 and MAVS mRNA expressions in TGEV-infected IPEC-J2 cells. However, the knockdown of RIG-I and MDA5 but not TLR3 and TLR7 significantly reduced the NF-κB p65 phosphorylation level and inflammatory cytokines levels in TGEV-infected IPEC-J2 cells. Our results indicated that ATRA attenuated TGEV-induced IPEC-J2 cells damage via suppressing inflammatory response, the mechanism of which is associated with the inhibition of TGEV-mediated activation of the RLRs/NF-κB signaling pathway.

A novel hypothesis for COVID-19 pathogenesis: Retinol depletion and retinoid signaling disorder

The SARS-CoV-2 virus has caused a worldwide COVID-19 pandemic. In less than a year and a half, more than 200 million people have been infected and more than four million have died. Despite some improvement in the treatment strategies, no definitive treatment protocol has been developed. The pathogenesis of the disease has not been clearly elucidated yet. A clear understanding of its pathogenesis will help develop effective vaccines and drugs. The immunopathogenesis of COVID-19 is characteristic with acute respiratory distress syndrome and multiorgan involvement with impaired Type I interferon response and hyperinflammation. The destructive systemic effects of COVID-19 cannot be explained simply by the viral tropism through the ACE2 and TMPRSS2 receptors. In addition, the recently identified mutations cannot fully explain the defect in all cases of Type I interferon synthesis. We hypothesize that retinol depletion and resulting impaired retinoid signaling play a central role in the COVID-19 pathogenesis that is characteristic for dysregulated immune system, defect in Type I interferon synthesis, severe inflammatory process, and destructive systemic multiorgan involvement. Viral RNA recognition mechanism through RIG-I receptors can quickly consume a large amount of the body's retinoid reserve, which causes the retinol levels to fall below the normal serum levels. This causes retinoid insufficiency and impaired retinoid signaling, which leads to interruption in Type I interferon synthesis and an excessive inflammation. Therefore, reconstitution of the retinoid signaling may prove to be a valid strategy for management of COVID-19 as well for some other chronic, degenerative, inflammatory, and autoimmune diseases.

All-trans retinoic acid plus high-dose dexamethasone as first-line treatment for patients with newly diagnosed immune thrombocytopenia: a multicentre, open-label, randomised, controlled, phase 2 trial

BACKGROUND

High-dose dexamethasone is the standard initial treatment for patients with immune thrombocytopenia, but many patients still relapse and require further treatments. All-trans retinoic acid has been shown to exert immunomodulatory effects and promote thrombopoiesis, and so we aimed to assess the activity and safety of all-trans retinoic acid plus high-dose dexamethasone as a first-line treatment for newly diagnosed patients with immune thrombocytopenia.

METHODS

This multicentre, open-label, randomised, controlled, phase 2 trial was done at six different tertiary medical centres in China. Eligible participants were adults (aged >18 years) with treatment-naive, newly diagnosed, primary immune thrombocytopenia who had either a platelet count of less than 30 × 109 platelets per L or a platelet count of less than 50 × 109 platelets per L and clinically significant bleeding. We randomly assigned (1:1) participants to receive either all-trans retinoic acid (10 mg orally twice daily for 12 weeks) plus high-dose dexamethasone (40 mg/day intravenously for 4 consecutive days) or high-dose dexamethasone alone using a central, web-based randomisation system. If patients did not respond by day 14, the 4-day course of dexamethasone was repeated. The primary endpoint was 6-month sustained response, defined as the maintenance of a platelet count of at least 30 × 109 platelets per L and at least 2-times higher than the baseline count and the absence of bleeding, with no need for rescue medication at this time. The primary endpoint was analysed by intention-to-treat and safety was assessed in all participants who received at least one dose of the study drug. This trial is registered with ClinicalTrials.gov, NCT04217148, and is now completed.

FINDINGS

Between Jan 1, 2020, and June 30, 2020, 132 patients were randomly assigned to either all-trans retinoic acid plus high-dose dexamethasone (n=66) or high-dose dexamethasone alone (n=66). Three patients did not receive their allocated treatment, leaving 129 in the safety analysis set. At 6 months, a significantly higher proportion of participants in the all-trans retinoic acid plus high-dose dexamethasone group (45 [68%] of 66) than in the high-dose dexamethasone monotherapy group (27 [41%] of 66) had a sustained response (OR 3·095, 95% CI 1·516-6·318; p=0·0017). The most common adverse events were dry skin (31 [48%] of 64 patients), headaches (12 [19%]), and insomnia (12 [19%]) in the combination group, and insomnia (ten [15%] of 65 patients) and anxiety or mood disorders (eight [12%]) in the monotherapy group. Both treatments were well tolerated and no grade 4 or worse adverse events occurred. There were no treatment-related deaths.

INTERPRETATION

The combination of all-trans retinoic acid and high-dose dexamethasone was safe and active in newly diagnosed patients with primary immune thrombocytopenia, providing a sustained response. This regimen represents a potential first-line treatment in this setting, but further studies are needed to validate its efficacy and safety.

FUNDING

The Beijing Municipal Science and Technology Commission, the National Natural Science Foundation of China, the Beijing Natural Science Foundation, the National Key Research and Development Program of China, and the Foundation for Innovative Research Groups of the National Natural Science Foundation of China.

TLR4 signaling in the development of colitis-associated cancer and its possible interplay with microRNA-155

Ulcerative colitis (UC) has closely been associated with an increased risk of colorectal cancer. However, the exact mechanisms underlying colitis-associated cancer (CAC) development remain unclear. As a classic pattern-recognition receptor, Toll like receptor (TLR)4 is a canonical receptor for lipopolysaccharide of Gram-negative bacteria (including two CAC-associated pathogens Fusobacterium nucleatum and Salmonella), and functions as a key bridge molecule linking oncogenic infection to colonic inflammatory and malignant processes. Accumulating studies verified the overexpression of TLR4 in colitis and CAC, and the over-expressed TLR4 might promote colitis-associated tumorigenesis via facilitating cell proliferation, protecting malignant cells against apoptosis, accelerating invasion and metastasis, as well as contributing to the creation of tumor-favouring cellular microenvironment. In recent years, considerable attention has been focused on the regulation of TLR4 signaling in the context of colitis-associated tumorigenesis. MicroRNA (miR)-155 and TLR4 exhibited a similar dynamic expression change during CAC development and shared similar CAC-promoting properties. The available data demonstrated an interplay between TLR4 and miR-155 in the context of different disorders or cell lines. miR-155 could augment TLR4 signaling through targeting negative regulators SOCS1 and SHIP1; and TLR4 activation would induce miR-155 expression via transcriptional and post-transcriptional mechanisms. This possible TLR4-miR-155 positive feedback loop might result in the synergistic accelerating effect of TLR4 and miR-155 on CAC development.

Dexamethasone and Fumaric Acid Ester Conjugate Synergistically Inhibits Inflammation and NF-κB in Macrophages

Macrophage-mediated inflammation drives autoimmune and chronic inflammatory diseases. Treatment with anti-inflammatory agents can be an effective strategy to reduce this inflammation; however, high concentrations of these agents can have immune-dampening and other serious side effects. Synergistic combination of anti-inflammatory agents can mitigate dosing by requiring less drug. Multiple anti-inflammatory agents were evaluated in combination for synergistic inhibition of macrophage inflammation. The most potent synergy was observed between dexamethasone (DXM) and fumaric acid esters (e.g., monomethyl fumarate (MMF)). Furthermore, this combination was found to synergistically inhibit inflammatory nuclear factor κB (NF-κB) transcription factor activity. The optimal ratio for synergy was determined to be 1:1, and DXM and MMF were conjugated by esterification at this molar ratio. The DXM-MMF conjugate displayed improved inhibition of inflammation over the unconjugated combination in both murine and human macrophages. In the treatment of human donor monocyte-derived macrophages, the combination of DXM and MMF significantly inhibited inflammatory gene expression downstream of NF-κB and overall performed better than either agent alone. Further, the DXM-MMF conjugate significantly inhibited expression of NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome-associated genes. The potent anti-inflammatory activity of the DXM-MMF conjugate in human macrophages indicates that it may have benefits in the treatment of autoimmune and inflammatory diseases.

Dietary intake of vegetables, fruit, and antioxidants and risk of ulcerative colitis: A case-control study in Japan

OBJECTIVES

Oxidative stress is considered one of the etiologic factors involved in ulcerative colitis (UC), yet there is limited epidemiologic information regarding the relationship between antioxidant intake and the risk of UC. The aim of the present case-control study in Japan was to examine the association between intake of green and yellow vegetables, other vegetables, fruit, vitamin C, vitamin E, retinol, alpha-carotene, beta-carotene, and cryptoxanthin and UC risk.

METHODS

A total of 384 cases within 4 y of diagnosis with UC and 665 controls were included in the study. Data on dietary intake and confounders were obtained using a self-reported questionnaire. Information on dietary factors was collected using a 169-item semiquantitative food-frequency questionnaire. Adjustment was made for sex, age, pack-y of smoking, alcohol consumption, history of appendicitis, family history of UC, education level, and body mass index.

RESULTS

Higher intake levels of other vegetables, vitamin C, and retinol were independently associated with a reduced risk of UC. The adjusted odds ratio between extreme quartiles was 0.51 (95% confidence interval [CI], 0.34-0.76; P for trend ≤ 0.001) for other vegetables, 0.45 (95% CI, 0.30-0.69, P for trend ≤ 0.001) for vitamin C, and 0.64 (95% CI, 0.43-0.95, P for trend = 0.04) for retinol. There were no associations between intake of green and yellow vegetables, fruit, vitamin E, alpha-carotene, beta-carotene, or cryptoxanthin and UC risk (P for trend = 0.29, 0.56, 0.89, 0.20, 0.69, and 0.22, respectively).

CONCLUSIONS

Intake of other vegetables, vitamin C, and retinol was inversely associated with UC risk.

Regulatory Action of all trans Retinoic Acid on Metastasis Induced lung Cell Metabolic Changes during Implantation of B16F10 Cancer Cells in C57BL6 Mice

The changes that occur during metastasis lodging is under intense research now to develop preventive new drugs to fight against the deadly metastasis. The molecular drug, all trans Retinoic Acid (ATRA) has regulatory effects on signal mediated metabolism. In this study, we have analyzed the metastasis facilitating metabolic changes in mice lung when a highly metastatic melanoma cell line (B16F10) having potency to lodge in lung was implanted via tail vein injection into C57BL/6 mice (1×106 cells/ml in PBS). One group of implanted mice were treated with 0.60 mg of ATRA per Kg body weight daily for 21 days. The alteration of protein, enzymatic and non-enzymatic antioxidants (SOD, Catalase, GPX, GSH) levels and the lipid profile with cholesterol level were evaluated in the lung tissues. The ATRA treatment caused 62.16% inhibition on metastatic nodule formation. Compared to normal mice, the cancer control mice showed an increased (p≤ 0.01**) total protein, LPO and NO and a decreased antioxidant. In ATRA treated group, all these levels were reverted to near normal levels with a high significance (p≤ 0.01**) difference from untreated cancer mice. The lipid profile and cholesterol level also were altered in cancer and were normalized in ATRA treated group with high significance (p≤ 0.01**). All these results implies that the metabolic changes induced in the lung tissue during metastatic lodging of melanoma cells were prevented and regularized by the ATRA treatment in vivo which give a scope of anti-metastatic therapy using ATRA.

Clinical significance of changes of TLR4/MyD88/NF-κB signaling pathway in peripheral blood mononuclear cells of gastric cancer patients with Helicobacter pylori infection

BACKGROUND

The correlation between Helicobacter pylori (H. pylori) and gastric cancer has been widely recognized in the world. The abnormal expression of TLR4/MyD88/NF-κB signaling pathway related factors is obvious in gastric cancer patients, suggesting that this pathway is closely related to the occurrence and development of gastric cancer. However, there is also a correlation between the TLR4/MyD88/NF-κB signaling pathway and H. pylori infection in gastric cancer patients.

AIM

To investigate the clinical significance of changes of the TLR4/MyD88/NF-κB signaling pathway in peripheral blood mononuclear cells (PBMCs) of patients with gastric cancer infected by H. pylori.

METHODS

Eighty gastric cancer patients treated at Huzhou Third People's Hospital from October 2017 to October 2020 were selected as a study group, and 50 healthy ts volunteers were selected as a control group. The expression levels of TLR-4, NF-κB, and myeloid differentiation factor (MyD88) in PBMCs of gastric cancer patients with different pathological characteristics and H. pylori infection status were compared between the two groups, and the correlation between TLR-4, NF-κB, and MyD88 protein levels and H. pylori infection was analyzed.

RESULTS

Compared with the control group, the expression levels of TLR-4, NF-κB, and MyD88 in the study group were significantly higher than those of the control group (P < 0.05). The expression of TLR4/MyD88/NF-κB signaling pathway related molecules differed significantly in gastric cancer patients with different clinical stages, lymph node metastasis status, and depth of invasion (P < 0.05), and TLR4/MyD88/NF-κB expression differed significantly in different gender and age groups (P < 0.05). The expression of TLR-4, NF-κB, and MyD88 in the H. pylori positive group was significantly higher than that of the H. pylori negative group (P < 0.05). Pearson analysis showed that H. pylori infection was positively correlated with the expression of TLR-4, NF-κB, and MyD88 (r = 0.726, 0.684, and 0.631, P < 0.01).

CONCLUSION

The expression levels of TLR4/MyD88/NF-κB signaling pathway related molecules in peripheral blood mononuclear cells (PBMCs) of patients with gastric cancer increase significantly, and are significantly different among groups with different pathological characteristics and parameters. It is speculated that H. pylori infection may participate in the occurrence and development of gastric cancer by inducing the abnormal expression of the TLR4/MyD88/NF-κB signaling pathway.

All-trans-retinoic acid ameliorates atherosclerosis, promotes perivascular adipose tissue browning, and increases adiponectin production in Apo-E mice

All-trans-retinoic acid (atRA), an active metabolite of vitamin A, exerts a potential role in the prevention of cardiovascular diseases. It has been shown that atRA ameliorates atherosclerosis while the exact mechanism underlying this protection remains unknown. This study investigated the influence of atRA on insulin resistance (IR), atherosclerosis, and the process of perivascular adipose tissue (PVAT) browning. Moreover, syntheses of adiponectin, adipokine with anti-atherogenic effects, and tumor necrosis factor-alpha (TNF-α), a pro-inflammatory cytokine, were determined in PVAT. Apolipoprotein E-deficient mice (Apo-E) and control C57BL/6J wild-type mice were treated with atRA (5 mg/kg/day) or vehicle (corn oil) by plastic feeding tubes for 8 weeks. Long-term atRA treatment in Apo-E mice did not affect insulin resistance. AtRa administration ameliorated atherosclerosis, induced PVAT browning, and increased adiponectin production in PVAT in Apo-E mice. Furthermore, atRA increased nitric oxide (NO) level but did not affect adiponectin concentration in the aorta of Apo-E mice. These results indicate that atRA ameliorates atherosclerosis in Apo-E mice. We also observed the browning of PVAT. Besides, atRA increased the synthesis of adiponectin in PVAT and augmented NO level in the aorta in ApoE mice.

Curcumin inhibits the growth of liver cancer by impairing myeloid-derived suppressor cells in murine tumor tissues

Curcumin, one of the active ingredients of Curcuma longa (Jianghuang), has been reported to exert multiple bioactivities, including pro-apoptotic and anti-inflammatory activities. In recent years, curcumin has been extensively studied, and it has been revealed that curcumin inhibits the growth of numerous types of cancer. However, to the best of our knowledge, the inhibitory effects of curcumin on the activation or expansion of myeloid-derived suppressor cells (MDSCs) in liver cancer and the underlying mechanism have not yet been determined. Therefore, the present study aimed to investigate the inhibitory effect of curcumin on MDSC activity and the associated anti-neoplastic mechanism in a HepG2 ×enograft mouse model. The effect of curcumin on the viability of Huh-7, MHCC-97H and HepG2 cells in vitro was analyzed using a Cell Counting Kit-8 assay. The effects of curcumin on tumor growth, numbers of MDSCs, expression levels of proteins involved in the toll-like receptor 4 (TLR4)/NF-κB signaling pathway, levels of related inflammatory factors and angiogenesis were determined in HepG2 ×enograft model mice, which were given different doses of curcumin via intragastrical administration. The results of the present study revealed that curcumin inhibited the viability of Huh-7, MHCC-97H and HepG2 cells and the growth of HepG2 ×enograft tumors in mice. Flow cytometric analysis indicated that curcumin reduced the number of MDSCs in mouse xenograft tumors. In addition, the results demonstrated that curcumin inhibited the TLR4/NF-κB signaling pathway and the expression of inflammatory factors, including IL-6, IL-1β, prostaglandin E2 and cyclooxygenase-2, in mouse xenograft tumors. Furthermore, curcumin suppressed the secretion of granulocyte-macrophage colony-stimulating factor (GM-CSF) and granulocyte-colony stimulating factor (G-CSF), which are essential factors for MDSCs modulation, in tumor tissues. Additionally, curcumin was revealed to inhibit angiogenesis, which was demonstrated by the downregulation of the expression levels of vascular endothelial growth factor, CD31 and α-smooth muscle actin in western blotting, immunohistochemistry and immunofluorescence experiments. In conclusion, the findings of the present study identified a novel mechanism via which curcumin may suppress the growth of liver cancer by reducing the numbers of MDSCs and subsequently disrupting the process of angiogenesis. These conclusions were supported by the observed inactivation of the TLR4/NF-κB signaling pathway-mediated inflammatory response and the downregulation of GM-CSF and G-CSF secretion in xenograft tissues.

Function of intestinal barrier protected by regulating the miR-199a-3p in ulcerative colitis: Modulation of IL-23/IL-17A axis

Ulcerative colitis is a chronic inflammatory bowel disorder, which is having higher mortality rate. The present report evaluates the protective effect of miR-199a-3p oligomer for the treatment of Ulcerative colitis (UC). Ulcerative colitis was induced by administration of dextran sulfate sodium [DSS (3%)] with drinking water for the duration of one week in mice and miR-199a-3p oligomer was treated for the same duration. Effect of miR-199a-3p oligomer was determined by estimating the body weight, blood stool and length of colon in UC mice. Inflammatory cytokines, oxidative stress parameters and Treg/Th17 ratio was determined in the serum, intestinal and spleen tissue of UC mice. mRNA expression of TGFβ, Foxp3, RORγt and STAT3 was estimated in the intestinal tissue of UC mice. Moreover, permeability of intestine was determined by estimating the expression of FITC-dextran in the serum and expression of junction protein in the tissue of UC mice. The data of the study suggest that treatment with miR-199a-3p oligomer ameliorates the altered condition in ulcerative colitis mice. There was reduction in the level of cytokines and parameters of oxidative stress in the intestine of miR-199a-3p oligomer than UC group. Moreover, intestinal permeability was enhanced in miR-199a-3p oligomer treated UC mice. The level of Th17 in the serum and mRNA expression of TGFβ, Foxp3, RORγt and STAT3 was attenuated in miR-199a-3p oligomer treated UC mice. In conclusion, the data of the study suggest that treatment with miR-199a-3p oligomer ameliorates intestinal barrier in ulcerative colitis by down regulating the IL-17A/IL-23 axis.

Probiotic Bacillus Spores Together with Amino Acids and Immunoglobulins Exert Protective Effects on a Rat Model of Ulcerative Colitis

In inflammatory bowel disease (IBD), experimental models have proven to be important tools for evaluating potential therapeutic agents and for investigating the mechanisms of pathogenesis. Oxidative stress and the immune response have been associated with acetic acid (AA)-induced ulcerative colitis (UC). Our study aimed to evaluate, for the first time, the ability of a spore-based probiotic and an amino acid and immunoglobulin supplement in reducing tissue damage and inflammatory responses in an experimental animal model of UC. Forty-two Wistar rats were divided into six groups, receiving 1% carboxymethylcellulose, 4% AA, MegaSporeBiotic™ (MSB; 1 × 10⁹ colony forming units/day) and MegaMucosa™ (MM; 70 mg/100 g/day). Pretreatment with MSB or MM alone and in combination significantly lowered inflammation and reduced damage to the colonic mucosa. Pretreatment with these agents resulted in levels of proinflammatory cytokines, vascular tight junction proteins, and measures of oxidative stress similar to those reported for methylprednisolone, one of the first-line therapies for moderate to severe activity of UC. The protection was further confirmed by histologic analysis of the colon tissue. In conclusion, pretreatment with probiotic spore-forming Bacillus strains and a supplement of amino acids in combination with immunoglobulins exhibited anti-inflammatory and antioxidant effects in an AA-induced rat model of UC.

Systematic Investigation of the Efficacy of Sinitang Decoction Against Ulcerative Colitis

The aim of this study was to investigate the precise clinical use of Sinitang decoction (SNT) in ulcerative colitis (UC). Network pharmacology-based analysis of the drug components-targets-diseases-pathways was used to predict the possible clinical applications of SNT. Next, 2,4,6-trinitrobenzenesulfonic acid (TNBS) was used to establish a rat model of UC, and the efficacy of SNT against UC was tested, followed by a proteomic analysis of the specific signatures regulated by SNT against UC. SNT was predicted to be effective in inflammatory bowel disease, UC, and several other diseases. In the rats with UC, SNT decreased the disease activity index and colon mucosal damage index compared to the untreated UC model rats. Additionally, SNT reversed the upregulated levels of serum tumor necrosis factor (TNF)-α, prostaglandin E₂ (PGE₂), interleukin (IL)-6, and nitric oxide (NO) in UC model rats. The proteomic analysis identified 78 proteins that were differentially regulated by SNT in the rats with UC, which were associated with the Gene Ontology terms sulfur compound binding, calcium ion binding, and Toll-like receptor (TLR)-4 binding. Among these differentially regulated proteins, C-reactive protein (CRP) and collagen alpha-1(XII) chain (COL12A1) were found to be signature proteins associated with the efficacy of SNT against UC. This study represents the first precise investigation of the efficacy and mechanisms of SNT against UC, and shows that SNT is a promising candidate for personalized management of UC.

Anemoside B4 prevents acute ulcerative colitis through inhibiting of TLR4/NF-κB/MAPK signaling pathway

Anemoside B4 (B4) is a compound extracted from Pulsatilla chinensis(P. chinensis). Pharmacological studies have proved that it has certain anti-inflammatory activity. Acute ulcerative colitis (ulcerative colitis) is a non-specific inflammatory disease whose pathogenesis is not completely known, and there is no effective drugs. The purpose of this study was to investigate the protective effect of B4 on ulcerative colitis and its mechanism. In this study, the C57BL/6 mice model of ulcerative colitis was established by DSS [3% (w/v)] and treated with intraperitoneal injection of B4 and oral administration of mesalazine, respectively. During the experiment, the clinical symptoms of the mice were scored by the disease activity index (DAI). Histopathological changes were observed by HE staining. In addition, the effect of LPS on Raw264.7 cells was also studied. In vivo studies showed that B4 could prevent DSS-induced colitis mice from losing weight, shortening colon length and improving pathological changes of colon tissues. B4 significantly reduced levels of inflammatory cytokines IL-1β, IL-6, and TNF-α in colon tissues. In vitro experiments, B4 was almost nontoxic to Raw264.7 cells and could protect the Raw264.7 cells induced by LPS. In terms of mechanism, B4 significantly inhibited the activation of the TLR4 signaling pathway induced by DSS and down-regulate the expression of key proteins in the TLR4/NF-κB/MAPK signaling pathway in Raw264.7 cells induced by LPS. These findings suggest that the inhibition of B4 on ulcerative colitis may be through the TLR4/NF-κB/MAPK pathway. Therefore, B4 may be used as a potential drug for the treatment of ulcerative colitis.

Nitric Oxide (NO) and NO Synthases (NOS)-Based Targeted Therapy for Colon Cancer

Colorectal cancer (CRC) is one of the most lethal malignancies worldwide and CRC therapy remains unsatisfactory. In recent decades, nitric oxide (NO)-a free-radical gas-plus its endogenous producer NO synthases (NOS), have attracted considerable attention. NO exerts dual effects (pro- and anti-tumor) in cancers. Endogenous levels of NO promote colon neoplasms, whereas exogenously sustained doses lead to cytotoxic functions. Importantly, NO has been implicated as an essential mediator in many signaling pathways in CRC, such as the Wnt/β-catenin and extracellular-signal-regulated kinase (ERK) pathways, which are closely associated with cancer initiation, metastasis, inflammation, and chemo-/radio-resistance. Therefore, NO/NOS have been proposed as promising targets in the regulation of CRC carcinogenesis. Clinically relevant NO-donating agents have been developed for CRC therapy to deliver a high level of NO to tumor sites. Notably, inducible NOS (iNOS) is ubiquitously over-expressed in inflammatory-associated colon cancer. The development of iNOS inhibitors contributes to targeted therapies for CRC with clinical benefits. In this review, we summarize the multifaceted mechanisms of NO-mediated networks in several hallmarks of CRC. We review the clinical manifestation and limitations of NO donors and NOS inhibitors in clinical trials. We also discuss the possible directions of NO/NOS therapies in the immediate future.

Targeting TLR4-dependent inflammation in post-hemorrhagic brain injury

Recent data have implicated inflammation of the cerebrospinal fluid spaces after subarachnoid, intraventricular, and intracerebral hemorrhage to be a critical driver of multiple secondary brain injuries such as hydrocephalus, cerebral edema, and vasospasm. While TLR4-dependent reparative inflammation is an important protective response that can eliminate physical irritants and damaged cells, sustained or inappropriately triggered inflammation can initiate or propagate disease.Areas covered: We review recent advances in our understanding of how TLR4, including its upstream damage-associated molecular patterns and its downstream MyD88-dependent and independent signaling pathways, contributes to hemorrhage-induced inflammation in numerous brain diseases. We discuss prospects for the pharmacotherapeutic targeting of TLR4 in these disorders, including the use of repurposed FDA-approved agents.Expert opinion: TLR4 inhibitors with good blood-brain-barrier (BBB) penetration could be useful adjuncts in post-hemorrhagic hydrocephalus and multiple other diseases associated with brain hemorrhage and inflammation.

Genomic and molecular alterations in human inflammatory bowel disease-associated colorectal cancer

Patients with inflammatory bowel disease are at increased risk of colorectal cancer, which has worse prognosis than sporadic colorectal cancer. Until recently, understanding of pathogenesis in inflammatory bowel disease-associated colorectal cancer was restricted to the demonstration of chromosomic/microsatellite instabilities and aneuploidy. The advance of high-throughput sequencing technologies has highlighted the complexity of the pathobiology and revealed recurrently mutated genes involved in the RTK/RAS, PI3K, WNT, and TGFβ pathways, leading to potentially new targetable mutations. Moreover, alterations of mitochondrial DNA and the dysregulation of non-coding sequences have also been described, as well as several epigenetic modifications. Although recent studies have brought new insights into pathobiology and raised the prospect of innovative therapeutic approaches, the understanding of colorectal carcinogenesis in inflammatory bowel disease and how it differs from sporadic colorectal cancer remains not fully elucidated. Further studies are required to better understand the pathogenesis and molecular alterations leading to human inflammatory bowel disease-associated colorectal cancer.

Protective Effect of Iridoid Glycosides of the Leaves of Syringa oblata Lindl. on Dextran Sulfate Sodium-Induced Ulcerative Colitis by Inhibition of the TLR2/4/MyD88/NF-κB Signaling Pathway

Iridoid glycoside (IG) is the major active fraction extracted from the leaves of Syringa oblata Lindl. In view of its antimicrobial and antidiarrheal potential, it could be beneficial for the treatment of ulcerative colitis (UC). In the present study, IG (20, 40, and 80 mg/kg) was administered orally for 14 days to dextran sulfate sodium- (DSS-) induced colitis rats. The anti-inflammatory effects of IG on DSS-induced UC were evaluated by comparing observations in DSS-induced colitis and drug-treated groups using disease activity index (DAI), macroscopic score, histological analysis, and apoptosis assay. To elucidate the antioxidant mechanisms of IG on NOX-dependent ROS production, the activities of 8-OHdG, NOX1, and NOX2 in DSS-induced colitis were determined. The levels of proinflammatory cytokines such as IL-2, IL-4, IL-5, IL-12p40, and IL-13 were detected. The inflammation-associated protein and mRNA expressions of TLR-2, TLR-4, MyD88, and NF-κBp65 were assessed by immunohistochemistry and real-time quantitative PCR, respectively. The results suggested that IG treatment significantly reduced DAI, macroscopic score, and histological damage compared to untreated animals (p < 0.01), whereas administration of IG remarkably attenuated the upregulation of 8-OHdG, NOX1, and NOX2 and the expression of proinflammatory cytokines such as IL-2, IL-4, IL-5, IL-12p40, and IL-13 in DSS-treated rats in a concentration-dependent manner. In addition, IG treatment could dose dependently suppress the protein and mRNA levels of TLR-2, TLR-4, MyD88, and NF-κBp65. The dose of IG that produced the most significant protective effect was 80 mg/kg. The above results demonstrate that IG exerts its inhibitory effect on cell apoptosis, oxidative stress, and proinflammatory cytokines in DSS-induced colitis through modulation of the TLR2/4/MyD88/NF-κB signaling pathway.

Retinoid acid induced 16 deficiency aggravates colitis and colitis-associated tumorigenesis in mice

Inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC) is a serious health issue, but etiopathological factors remain unclear. Although some studies reported the roles of Retinoid acid induced 16 (RAI16) in the tumorigenesis of hepatocellular carcinoma and PKA signaling, the roles of RAI16 in IBD and CRC are undressed. RAI16^−/− mice were generated and the roles of RAI16 were addressed in dextran sodium sulfate (DSS) or azoxymethane (AOM)-DSS induced IBD or CAC mouse models, respectively. At first, RAI16^−/− mice were viable, fertile with no apparent defects. Then, it was found that RAI16^−/− mice were more susceptibility to colitis induced by DSS than wild type (WT) littermates, which was evaluated by disease activity index and histological score. Furthermore, the expressions of tissues repair associated molecules Cox2, Ereg and MMP-10 were significantly decreased in RAI16^−/− colon under DSS treatment. Gut barrier related genes including antimicrobial peptides Reg3b and Reg3g and intestinal mucus genes Muc4, Muc6 and Muc20 were reduced in RAI16^−/− colon. These findings indicated that RAI16 may function to affect genes involved in intestinal barrier function and immunoprotective inflammation. Accordingly, RAI16^−/− mice displayed significantly increased tumor burden compared with WT mice assessed in CAC model induced by AOM/DSS. Much more Ki67 + nuclei were observed in RAI16^−/− tumors suggesting RAI16 to be critical in colonic cell proliferation during tumorigenesis. Conclusively, we demonstrate the roles of RAI16 in colonic inflammation and inflammation-associated tumorigenesis by using a novel RAI16^−/− mouse model for the first time.

Inflammation and Inflammatory Cytokine Contribute to the Initiation and Development of Ulcerative Colitis and Its Associated Cancer

Dysregulated inflammatory responses play a pivotal role in the initiation, development, and progression of tumors, as demonstrated by the association between ulcerative colitis and the increased risk of colon carcinoma. In this review, the underlying mechanisms for the initiation and development of ulcerative colitis and colitis-associated cancer are described, mainly focusing on the inflammation and inflammatory cytokine. Disruption of the intestinal mucosal barrier and bacterial invasion resulted in intestinal inflammation; and further TLR4/NF-κB stimulation in intestinal epithelial cells, inflammatory cell infiltration, and inflammatory cytokine release all confer survival advantages to or promote abnormal proliferation in susceptible cells. Importantly, the respective roles of TLR4/NF-κB, TNF-α, and IL-6 in intestinal epithelial cells and inflammatory cells are summarized in detail. A thorough understanding of these molecular mechanisms may help researchers and clinicians to explore novel approaches for the prevention and treatment of colitis-associated cancer.

PTPRO exaggerates inflammation in ulcerative colitis through TLR4/NF-κB pathway

Previous studies have implicated protein tyrosine phosphatase receptor type O (PTPRO) as a key regulator in inflammation-associated diseases; however, its role in ulcerative colitis (UC) remains largely unknown. Thus, we aim to elucidate the potential role and underlying mechanism of PTPRO in UC. In this study, increased expression of PTPRO, toll-like receptor (TLR4) and inflammatory cytokines were observed in mucosal tissues (MTs) from inflamed areas and lamina propria mononuclear cells (LPMCs) of patients with UC compared with those from healthy controls. Then, it was manifested that PTPRO promoted the expression of TLR4 and proinflammatory cytokines in lipopolysaccharide-induced (LPS-induced) inflammatory macrophage model. Besides, PTPRO inhibited the proliferation of intestinal epithelial cells (IECs) but enhanced the apoptosis of IECs in macrophages. Moreover, levels of phosphorylated nuclear factor κB (NF-κB)/p65 and inhibitor of NF-κB α (IκBα) were more significantly increased in PTPRO overexpressed macrophages. In addition, the area under receiver operating characteristic curve was 0.807 (95%CI = 0.686-0.958, P < .001) suggesting PTPRO as an ideal diagnostic marker for UC. Taken these, the present study shows strong evidence that PTPRO exaggerates inflammation in UC via TLR4/NF-κB signaling pathway.

Albumin nano-encapsulation of caffeic acid phenethyl ester and piceatannol potentiated its ability to modulate HIF and NF-kB pathways and improves therapeutic outcome in experimental colitis

Hypoxia inducible factor and nuclear factor-kappa beta pathways have been proposed as therapeutic targets for several inflammatory diseases. Caffeic acid phenethyl ester (CAPE) and piceatannol (PIC) are natural anti-inflammatory compounds; however, poor bioavailability and limited understanding of biomolecular mechanistic limits its clinical use. The aims of this study are to enhance bioavailability and investigate their impact on nuclear p65 and HIF-1α for the first time in experimental colitis.Dextran sulphate sodium was used to induce colitis in mice and effect of either free CAPE/PIC or CAPE/PIC loaded albumin nanoparticles treatment was observed on disease development and levels of cellular p65 and HIF-1α.Our results indicate that albumin nano-encapsulation of CAPE/PIC not only enhances its anti-inflammatory potential but also potentiates its ability to effectively modulate inflammation related biomolecular pathways. Hence, combining nanotechnology with natural compounds could result in development of new therapeutic options for IBD.

Vitamin A and inflammatory bowel diseases: from cellular studies and animal models to human disease

Vitamin A (VA) and metabolites such as Retinoic Acid (RA) and all-trans-RA (at-RA) are crucial in the modulation of the immune system and may be determinative in the balance of the immune responses. Inflammatory bowel diseases (IBD) consist of chronic relapsing and heterogeneous disorders with not well-known etiology. Due to its role in inflammatory processes, VA may be helpful in the treatment of IBD. Area covered: As VA plays a significant role in the inflammatory processes, this review aims to show the potential role of this vitamin in IBD, searching for cellular studies, animal models, and studies with humans. Expert commentary: Many studies have described the importance of alternative therapeutic approaches for IBD. Due to its role in the immune system, VA may also exert an indispensable role in the IBD. Nevertheless, some authors have shown that these compounds could stimulate the release of pro-inflammatory cytokines. For these reasons, more studies should be performed to establish the precise mechanisms of VA and its metabolites in systemic and intestinal inflammation.

Multi-Target Cinnamic Acids for Oxidative Stress and Inflammation: Design, Synthesis, Biological Evaluation and Modeling Studies

Inflammation is a complex phenomenon that results as a healing response of organisms to different factors, exerting immune signaling, excessive free radical activity and tissue destruction. Lipoxygenases and their metabolites e.g., LTB₄, are associated with allergy, cell differentiation and carcinogenesis. Lipoxygenase 12/15 has been characterized as a mucosal-specific inhibitor of IgA and a contributor to the development of allergic sensitization and airway inflammation. Development of drugs that interfere with the formation or effects of these metabolites would be important for the treatment of various diseases like asthma, psoriasis, ulcerative colitis, rheumatoid arthritis, atherosclerosis, cancer and blood vessel disorders. In this study we extended our previous research synthesizing a series of multi-target cinnamic acids from the corresponding aldehydes with suitable 4-OH/Br substituted phenyl acetic acid by Knoevenagel condensation. The final products 1i, 3i, 3ii, 4i, 6i, 6ii, and 7i were obtained in high yields (52–98%) Their structures were verified spectrometrically, while their experimentally lipophilicity was determined as R_M values. The novel derivatives were evaluated for their antioxidant activity using DPPH, hydroxyl radical, superoxide anion and ABTS^+•, anti-lipid peroxidation and soybean lipoxygenase inhibition assays. The compounds presented medium interaction with DPPH (30–48% at 100 µM). In contrast all the synthesized derivatives strongly scavenge OH radicals (72–100% at 100 µM), ABTS^+• (24–83% at 100 µM) and presented remarkable inhibition (87–100% at 100 µM) in linoleic acid peroxidation (AAPH). The topological polar surface of the compounds seems to govern the superoxide anion scavenging activity. Molecular docking studies were carried out on cinnamic acid derivative 3i and found to be in accordance with experimental biological results. All acids presented interesting lipoxygenase inhibition (IC₅₀ = 7.4–100 µM) with compound 3i being the most potent LOX inhibitor with IC₅₀ = 7.4 µM combining antioxidant activities. The antioxidant results support the LOX inhibitory activities. The recorded in vitro results highlight compound 3i as a lead compound for the design of new potent lipoxygenase inhibitors for the treatment of asthma, psoriasis, ulcerative colitis, rheumatoid arthritis, atherosclerosis, cancer and blood vessel disorders.