Role of NF-kappaB activation in intestinal immune homeostasis

Free total rhubarb anthraquinones protect intestinal mucosal barrier of SAP rats via inhibiting the NLRP3/caspase-1/GSDMD pyroptotic pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Rhubarb is the peeled and dried roots of Rheum palmatum L. and Rheum tanguticum Maxim. ex Balf. or Rheum officinale Baill. Free total rhubarb anthraquinones (FTRAs) were isolated and extracted from rhubarb. Previous studies have revealed that the early administration of FTRAs protects the intestinal mucosal barrier in rats with severe acute pancreatitis (SAP), the mechanism of which is not yet clear. However, we observed an enhanced expression of intestinal pyroptotic factors in rats treated with SAP, which may be related to the mechanism of intestinal barrier protection by FTRAs.

AIM OF THE STUDY

The main objective of this study was to investigate the mechanism by which FTRAs protect the intestinal mucosal barrier in SAP rats, focusing on the classical pyroptosis pathway.

MATERIALS AND METHODS

SAP was induced in rats through retrograde injection of sodium taurocholate via the pancreaticobiliary duct. Subsequently, FTRAs (22.5, 45, and 90 mg/kg), rhubarb (900 mg/kg, positive control), and saline (control) were administered at 0 h (immediately), 12 h, and 24 h post-surgery. Pancreatic and intestinal tissue injury, positive PI staining rate, and expression levels of various factors in intestinal tissues were compared across different groups. These factors include diamine oxidase (DAO), lactate dehydrogenase (LDH), high mobility group box chromosomal protein 1(HMGB1) and pro-inflammatory factors in intestinal and serum, pyroptosis-associated factors, toll-like receptor 4 (TLR-4), nuclear factor kappa-B (NF-kB), apoptosis-associated speck-like protein (ASC), NOD-like receptor protein 3 (NLRP3), cysteine protease-1 (caspase-1) and Gasdermin (GSDMD).

RESULTS

The findings indicated that FTRAs protected the damaged intestine and pancreas and restored the expression of intestinal epithelial junction proteins in SAP rats. Additionally, it reduced intestinal and serum levels of DAO, interleukin 1, interleukin 18, HMGB1, and LDH, attenuated intestinal Positive PI staining rate, and significantly decreased the expressions of TLR-4, NF-kB, ASC, NLRP3, caspase-1 and GSDMD in SAP rats.

CONCLUSIONS

The results suggest that FTRAs inhibited pyroptosis through down-regulation of the NLRP3-Caspase-1-GSDMD and TLR-4- NF-kB signaling pathways of intestinal tissues., thereby protecting the intestinal barrier of SAP rats.

Current Knowledge on the Preparation and Benefits of Cruciferous Vegetables as Relates to In Vitro, In Vivo, and Clinical Models of Inflammatory Bowel Disease

Inflammatory bowel disease is a chronic condition with a significant economic and social burden. The disease is complex and challenging to treat because it involves several pathologies, such as inflammation, oxidative stress, dysbiosis, and intestinal damage. The search for an effective treatment has identified cruciferous vegetables and their phytochemicals as potential management options for inflammatory bowel disease because they contain prebiotics, probiotics, and anti-inflammatory and antioxidant metabolites essential for a healthy gut. This critical narrative style review provides a robust insight into the pharmacological effects and benefits of crucifers and their documented bioactive compounds in in vitro and in vivo models, as well as clinical inflammatory bowel disease. The review highlights the significant impact of crucifer preparation and the presence of glucosinolates, isothiocyanates, flavonoids, and polyphenolic compounds, which are essential for the anti-inflammatory and antioxidative benefits of cruciferous vegetables, as well as their ability to promote the healthy microbial community and maintain the intestinal barrier. This review may serve as a viable nutritional guide for future research on methods and features essential to developing experiments, preventions, and treatments for inflammatory bowel disease. There is limited clinical information and future research may utilize current innovative tools, such as metabolomics, for adequate knowledge and effective translation into clinical therapy.

MicroRNA-29b-3p promotes intestinal permeability in IBS-D via targeting TRAF3 to regulate the NF-κB-MLCK signaling pathway

Irritable bowel syndrome with predominant diarrhea (IBS-D) is characterized by increased intestinal permeability. Previous studies have shown that the microRNA-29 gene is involved in the regulation of intestinal permeability in patients with IBS-D. NF-κB was proved to play a key role in inflammatory response of intestine and resultant disruption of tight junction integrity, whose activity could be inhibited by TNF Receptor-Associated Factor 3 (TRAF3). However, the exact mechanism that induces increased intestinal permeability in IBS-D patients has not been clarified. In this study, we found that microRNA-29b‑3p (miR-29b-3p) was significantly upregulated, while TRAF3 was decreased and the NF-κB-MLCK pathway was activated within the colonic tissue of IBS-D patients. Subsequently, we confirmed the targeting relationship between miR-29b-3p and TRAF3 through a double-luciferase reporter assay. Lentivirus transfection of NCM460 cells with miR-29b-3p-overexpressing and -silencing vectors demonstrated that the expression of TRAF3 was negatively correlated with the level of miR-29b-3p. The NF-κB/MLCK pathway was activated in the miR-29b-3p-overexpressing group and inhibited to some extent in the miR-29b-3p-silencing group. Results in WT and miR-29 knockout mice showed that miR-29b-3p levels were increased, TRAF3 levels were decreased, and the NF-κB/MLCK signaling was activated in the WT IBS-D group as compared with the WT control group. The protein levels of TRAF3 and TJs in the miR-29b-/- IBS-D group were partially recovered and NF-κB/MLCK pathway indicators were, to a certain extent, decreased as compared with the WT IBS-D group. These results suggested that miR-29b-3p deletion enhances the TRAF3 level in IBS-D mice and alleviates the high intestinal permeability. In brief, through the analysis of intestinal tissue samples from IBS-D patients and miR-29b-/- IBS-D mice, we showed that miR-29b-3p is involved in the pathogenesis of intestinal hyperpermeability in IBS-D via targeting TRAF3 to regulate the NF-κB-MLCK signaling pathway.

Anti-Inflammatory Effects of Allocryptopine via the Target on the CX3CL1-CX3CR1 axis/GNB5/AKT/NF-κB/Apoptosis in Dextran Sulfate-Induced Mice

Allocryptopine (ALL) is an isoquinoline alkaloid extracted from Macleaya cordata(Willd). R. Br., which has been claimed to have anti-inflammatory and neuroprotection properties. However, the mechanism by which ALL ameliorates inflammatory bowel disease (IBD) remains unclear. Here, we used network pharmacology and quantitative proteomic approaches to investigate the effect of ALL on IBD pathogenesis. Network pharmacology predicted potential targets and signaling pathways of ALL's anti-IBD effects. As predicted by network pharmacology, gene ontology (GO) analysis, in terms of the proteomic results, showed that the immune response in mucosa and antimicrobial humoral response were enriched. Further study revealed that the ALL-related pathways were the chemokine signaling pathway and apoptosis in the Kyoto Encyclopedia of Genes and Genomes (KEGG). In addition, we identified AKT1 as a hub for the critical pathways through protein-protein interaction (PPI) network analysis. Similar to mesalazine (MES), Western blot verified that ALL downregulated upstream chemokine CX3CL1 and GNB5 content to reduce phosphorylation of AKT and NF-κB, as well as the degree of apoptosis, to improve inflammatory response in the colon. Our research may shed light on the mechanism by which ALL inhibits the CX3CL1/GNB5/AKT2/NF-κB/apoptosis pathway and improves the intestinal barrier to reduce colitis response and act on the CX3CL1-CX3CR1 axis to achieve neuroprotection.

Hypothermic machine perfusion alleviates ischemia-reperfusion injury of intestinal transplantation in pigs

Background

Intestinal transplantation (IT) has become an important procedure for the treatment of irreversible intestinal failure. However, IT is extremely vulnerable to ischemia-reperfusion injury (IRI). Due to the limitations of static cold storage (SCS), hypothermic machine perfusion (HMP) is rapidly gaining popularity. In this study, the intestinal HMP system is established and HMP is compared with SCS.

Methods

An intestinal HMP system was built. Ten miniature pigs were randomly divided into the HMP and SCS groups, and their intestines were perfused using the HMP device and SCS, respectively, followed by orthotopic auto-transplantation. Analysis was done on the grafts between the two groups.

Results

Operation success rates of the surgery were 100% in both groups. The 7-day survival rate was 100% in the HMP group, which was significantly higher than that of the SCS group (20%, P< 0.05). The pathological results showed that fewer injuries of grafts were in the HMP group. Endotoxin (ET), IL-1, IL-6, IFN-γ and TNF-α levels in the HMP group were significantly lower than in the SCS group (P<0.05), whereas IL-10 levels were significantly higher (P<0.05).The intestinal expression levels of ZO-1 and Occludin were higher in the HMP group compared to the SCS group, whereas Toll-like receptor 4 (TLR4), nuclear factor kappa B (NFκB), and caspase-3 were lower.

Conclusions

In this study, we established a stable intestinal HMP system and demonstrated that HMP could significantly alleviate intestinal IRI and improve the outcome after IT.

Influence of Huangqin Decoction on the immune function and fecal microbiome of chicks after experimental infection with Escherichia coli O78

Huangqin Decoction (HQD), a traditional Chinese medicine formula from the Shang Han Lun written by Zhang Zhongjing, has been used in China for nearly two thousand years. According to the traditional Chinese medicine and previous literature, HQD has the effect of clearing heat, removing toxins, relieving diarrhea and pain. Therefore, HQD was used to prevent or cure many diseases, such as inflammation, diarrhea, malaria, and other acute or chronic gastrointestinal diseases. The effect of HQD, one-herb-absent HQD treatments and enrofloxacin (ENR) on the average daily gain (ADG), mortality rates, visceral index and toll-like receptors (TLRs), inflammatory factors and intestinal microflora in E. coli O78-inoculated chicks were investigated. HQD supplementation increased ADG and reduced the mortality rates caused by E. coli challenge, decreased the heart, liver, bursa of Fabricius (BF) and spleen index. HQD supplementation decreased the serum lysozyme (LZM), IL-1β, TNF-α, IL-10, IL-6 level, down-regulated the mRNA expression of TLR4, -5 and -15 in the spleen by E. coli challenged chicks, and up-regulated the mRNA expression of TLR4, -5 and -15 in BF. At the phylum level, HQD supplementation reversed the increase of Operational Taxonomic Unit (OTUs), decreased the relative abundance of harmful bacteria Proteobacteria, increased the relative abundance of probiotic bacteria Bacteroidetes and Firmicutes. At the genus level, HQD decreased the relative abundance of harmful bacteria Escherichia-Shigella and Pseudomonas. It means that HQD treatment reversed the change of the gut microbiota structure. Compared with HQD, HQD-DZ and HQD-HQ increased the mortality rates. HQD-HQ decreased the ADG and liver index. HQD-GC decreased the spleen index. All herb-absent increased the serum IL-6, but only the HQD-HQ and HQD-SY increased the serum TNF-α. All herb-absent did not activate the TLRs signaling pathways in spleen and BF of chicks. The harmful bacteria Escherichia-Shigella were increased in HQD-HQ and HQD-DZ treatments. HQD-DZ treatment also increased the level of Proteobacteria. The results showed that dietary supplementation with HQD, by down-regulating the mRNA expression of TLR4, -5 and -15 in the spleen, further decreasing the serum LZM and IL-1β, TNF-α, IL-10, IL-6 level, improves the immune function and reverses the change of fecal microbiome in chicks challenged with E. coli. In herb-absent supplementation, the results showed that SY and DZ play a key role in reducing the levels of inflammatory factors and keeping fecal microbiome balance respectively. More importantly, HQ is indispensable in HQD, not only play a key role in reducing the level of inflammatory factors, but also in keeping the balance of fecal microflora.

Polyphenolic Profile, Anti-Inflammatory and Anti-Nociceptive Activities of Some African Medicinal Plants

The aim of the present study was to investigate the polyphenolic profile and the anti-inflammatory and anti-nociceptive activities of four traditionally used medicinal plants from Burkina Faso: Parkia biglobosa, Detarium microcarpum, Vitellaria paradoxa and Sclerocarya birrea. The analysis of the main phenolic compounds was performed by the HPLC-UV-MS method. The anti-inflammatory effect of the aqueous bark extracts was investigated by the λ-carrageenan-induced rat paw edema test. The anti-nociceptive activity was evaluated by the Randall−Selitto test under inflammatory conditions. Seven phenolic acids (gallic, protocatechuic, gentisic, vanillic, p-coumaric, ferulic, and syringic acids), and three flavonoids (catechin, epicatechin, and quercitrin) were identified in the plant samples. High contents of gallic acid were determined in the D. microcarpum, P. biglobosa and S. birrea extracts (190−300 mg/100 g), and V. paradoxa extract was the richest in epicatechin (173.86 mg/100 g). The λ-carrageenan-induced inflammation was significantly reduced (p < 0.001) by the P. biglobosa and D. microcarpum extracts (400 mg/kg p.o.). Under the inflammatory conditions, a significant anti-nociceptive activity (p < 0.001) was obtained after 2−3 h from the induction of inflammation. The effects of the tested extracts could be related to the presence of polyphenols and could be useful in the management of certain inflammatory diseases.

DHA-Enriched Phospholipids and EPA-Enriched Phospholipids Alleviate Lipopolysaccharide-Induced Intestinal Barrier Injury in Mice via a Sirtuin 1-Dependent Mechanism

Intestinal barrier dysfunction has emerged as a potential contributor to the development of several severe diseases. Herein, the effect and underlying mechanism of DHA-enriched phospholipids (DHA-PL) and EPA-enriched phospholipids (EPA-PL) on protecting against lipopolysaccharide (LPS)-induced intestinal barrier injury were elucidated. C57BL/6J male mice were fed an AIN-93G diet containing 1% DHA-PL or EPA-PL for 4 weeks and then were intraperitoneally injected with LPS (10 mg/kg) to cause intestinal barrier injury. The results manifested that DHA-PL and EPA-PL pretreatment balanced apoptosis and autophagy in intestinal epithelial cells and maintained intestinal tight junction integrity. Our findings also demonstrated that cotreatment with EX-527, a sirtuin 1 specific inhibitor, hindered the role of DHA-PL and EPA-PL against LPS-evoked intestinal barrier injury through reversing the inhibitory action of them on NF-κB and MAPKs activation as well as their potentiating actions on Nrf2 nuclear translocation. Overall, DHA-PL and EPA-PL alleviated LPS-mediated intestinal barrier injury via inactivation of the NF-κB and MAPKs pathways as well as activating the Nrf2 antioxidant pathway via up-regulating sirtuin 1.

The deubiquitinase OTUD1 inhibits colonic inflammation by suppressing RIPK1-mediated NF-κB signaling

The E3 ubiquitin ligase (E3)-mediated ubiquitination and deubiquitinase (DUB)-mediated deubiquitination processes are closely associated with the occurrence and development of colonic inflammation. Ovarian tumor deubiquitinase 1 (OTUD1) is involved in immunoregulatory functions linked to infectious diseases. However, the effect of OTUD1 on intestinal immune responses during colonic inflammatory disorders such as inflammatory bowel disease (IBD) remains unclear. Here, we show that loss of OTUD1 in mice contributes to the pathogenesis of dextran sulfate sodium (DSS)-induced colitis via excessive release of proinflammatory cytokines. In addition, bone marrow transplantation experiments revealed that OTUD1 in hematopoietic cells plays a dominant role in protection against colitis. Mechanistically, OTUD1 physically interacts with receptor-interacting serine/threonine-protein kinase 1 (RIPK1) and selectively cleaves K63-linked polyubiquitin chains from RIPK1 to inhibit the recruitment of NF-κB essential modulator (NEMO). Moreover, the expression of OTUD1 in mucosa samples from ulcerative colitis (UC) patients was lower than that in mucosa samples from healthy controls. Furthermore, we demonstrate that the UC-associated OTUD1 G430V mutation abolishes the ability of OTUD1 to inhibit RIPK1-mediated NF-κB activation and intestinal inflammation. Taken together, our study unveils a previously unexplored role of OTUD1 in moderating intestinal inflammation by inhibiting RIPK1-mediated NF-κB activation, suggesting that the OTUD1-RIPK1 axis could be a potential target for the treatment of IBD.

Baicalin Alleviates LPS-Induced Oxidative Stress via NF-κB and Nrf2–HO1 Signaling Pathways in IPEC-J2 Cells

Baicalin is a natural plant extract with anti-inflammatory and anti-oxidant activities. However, the molecular mechanism of baicalin on oxidative stress in IPEC-J2 cells exposed to LPS remains to be unclear. In this study, LPS stimulation significantly increased Toll-like receptor 4, tumor necrosis factor-α, and interleukins (IL-6 and IL-1β) expression in IPEC-J2 cells, and it activated the nuclear factor (NF-κB) expression. While, baicalin exerted anti-inflammatory effects by inhibiting NF-κB signaling pathway. LPS stimulation significantly increased the levels of the oxidative stress marker MDA, inhibited the anti-oxidant enzymes catalase and superoxide dismutase, which were all reversed by baicalin pre-treatment. It was found that baicalin treatment activated the nuclear import of nuclear factor-erythroid 2 related factor 2 (Nrf2) protein, and significantly increased the mRNA and protein expression of its downstream anti-oxidant factors such as heme oxygenase-1 and quinone oxidoreductase-1, which suggested that baicalin exerted anti-oxidant effects by activating the Nrf2-HO1 signaling pathway. Thus, pretreatment with baicalin inhibited LPS - induced oxidative stress and protected the normal physiological function of IPEC-J2 cells via NF-κB and Nrf2–HO1 signaling pathways.

Silencing of CREB Inhibits HDAC2/TLR4/NF-κB Cascade to Relieve Severe Acute Pancreatitis-Induced Myocardial Injury

The purpose of the present study is to investigate the role of CREB in cardiomyocytes proliferation in regulation of HDAC2-dependent TLR4/NF-κB pathway in severe acute pancreatitis (SAP)-induced myocardial injury. The SAP rat model was developed by injecting sodium touracholate into SD rats and then infected with lentivirus vectors expressing sh-CREB in the presence/absence of LPS. The pathological alterations of rat pancreatic and cardiac tissues were observed by HE staining. TUNEL assay was used to study apoptosis of cardiomyocytes. Next, the loss- and gain-function assay was conducted in LPS-induced myocardial injury cardiomyocytes to define the roles of CREB, HDAC2, and TLR4 in cardiomyocyte proliferation, apoptosis, inflammation, and myocardial injury in vitro. ChIP assay was used to study the enrichment of CREB bound to HDAC2 promoter. RT-qPCR and Western blot analysis were used to detect the expressions of related mRNA and proteins in the NF-κB pathway, respectively. CREB was found to be overexpressed in both SAP tissues and cells. CREB directly bound to the promoter of HDAC2 and activated its expression. Overexpressed CREB or HDAC2 inhibited proliferation and promoted apoptosis of cardiomyocytes. Suppression of CREB inhibited the HDAC2/TLR4/NF-κB cascade to promote proliferation and inhibit apoptosis of cardiomyocytes. The in vitro results were validated in vivo experiments. Coherently, suppression of CREB can inhibit HDAC2/TLR4/NF-κB cascade to promote cardiomyocyte proliferation, thus ameliorating SAP-induced myocardial injury.

A Palmitoylethanolamide Producing Lactobacillus paracasei Improves Clostridium difficile Toxin A-Induced Colitis

Genetically engineered probiotics, able to in situ deliver therapeutically active compounds while restoring gut eubiosis, could represent an attractive therapeutic alternative in Clostridium difficile infection (CDI). Palmitoylethanolamide is an endogenous lipid able to exert immunomodulatory activities and restore epithelial barrier integrity in human models of colitis, by binding the peroxisome proliferator–activated receptor-α (PPARα). The aim of this study was to explore the efficacy of a newly designed PEA-producing probiotic (pNAPE-LP) in a mice model of C. difficile toxin A (TcdA)-induced colitis. The human N-acyl-phosphatidylethanolamine-specific phospholipase D (NAPE-PLD), a key enzyme involved in the synthesis of PEA, was cloned and expressed in a Lactobacillus paracasei that was intragastrically administered to mice 7 days prior the induction of the colitis. Bacteria carrying the empty vector served as negative controls (pLP).In the presence of palmitate, pNAPE-LP was able to significantly increase PEA production by 27,900%, in a time- and concentration-dependent fashion. Mice treated with pNAPE-LP showed a significant improvement of colitis in terms of histological damage score, macrophage count, and myeloperoxidase levels (−53, −82, and −70.4%, respectively). This was paralleled by a significant decrease both in the expression of toll-like receptor-4 (−71%), phospho-p38 mitogen-activated protein kinase (−72%), hypoxia-inducible factor-1-alpha (−53%), p50 (−74%), and p65 (−60%) and in the plasmatic levels of interleukin-6 (−86%), nitric oxide (−59%), and vascular endothelial growth factor (−71%). Finally, tight junction protein expression was significantly improved by pNAPE-LP treatment as witnessed by the rescue of zonula occludens-1 (+304%), Ras homolog family member A-GTP (+649%), and occludin expression (+160%). These protective effects were mediated by the specific release of PEA by the engineered probiotic as they were abolished in PPARα knockout mice and in wild-type mice treated with pLP. Herein, we demonstrated that pNAPE-LP has therapeutic potential in CDI by inhibiting colonic inflammation and restoring tight junction protein expression in mice, paving the way to next generation probiotics as a promising strategy in CDI prevention.

Abdominal paracentesis drainage attenuates intestinal inflammation in rats with severe acute pancreatitis by inhibiting the HMGB1-mediated TLR4 signaling pathway

BACKGROUND

Our previous studies confirmed that abdominal paracentesis drainage (APD) attenuates intestinal mucosal injury in rats with severe acute pancreatitis (SAP), and improves administration of enteral nutrition in patients with acute pancreatitis (AP). However, the underlying mechanisms of the beneficial effects of APD remain poorly understood.

AIM

To evaluate the effect of APD on intestinal inflammation and accompanying apoptosis induced by SAP in rats, and its potential mechanisms.

METHODS

SAP was induced in male adult Sprague-Dawley rats by 5% sodium taurocholate. Mild AP was induced by intraperitoneal injections of cerulein (20 μg/kg body weight, six consecutive injections). Following SAP induction, a drainage tube connected to a vacuum ball was placed into the lower right abdomen of the rats to build APD. Morphological changes, serum inflammatory mediators, serum and ascites high mobility group box protein 1 (HMGB1), intestinal barrier function indices, apoptosis and associated proteins, and toll-like receptor 4 (TLR4) signaling molecules in intestinal tissue were assessed.

RESULTS

APD significantly alleviated intestinal mucosal injury induced by SAP, as demonstrated by decreased pathological scores, serum levels of D-lactate, diamine oxidase and endotoxin. APD reduced intestinal inflammation and accompanying apoptosis of mucosal cells, and normalized the expression of apoptosis-associated proteins in intestinal tissues. APD significantly suppressed activation of the intestinal TLR4 signaling pathway mediated by HMGB1, thus exerting protective effects against SAP-associated intestinal injury.

CONCLUSION

APD improved intestinal barrier function, intestinal inflammatory response and accompanying mucosal cell apoptosis in SAP rats. The beneficial effects are potentially due to inhibition of HMGB1-mediated TLR4 signaling.

The role of polyphenols in poultry nutrition

In the last two decades, poultry and animal industries became increasingly interested in using plant-based feed supplements, herbs and their derivatives to retain or enhance their health and productivity. These health benefits for the host mainly attributed to the secondary plant metabolites, namely polyphenols. Polyphenols are renowned for their antioxidant, immunomodulatory, anti-mutagenic and anti-inflammatory properties. However, despite these advantages of polyphenols, they have been characterized by poor absorption in the gut and low concentration in target cells that compromise their role as effective antioxidants. The low bioavailability of polyphenols necessitates the need for further investigations to harness their full potential in poultry farms. This review is existing evidence about the bioavailability of polyphenols and their antioxidant, immunomodulatory, antimicrobial, detoxification properties and their impacts on poultry performance.

Non-coding RNAs in aortic dissection: From biomarkers to therapeutic targets

Aortic dissection (AD) is the rupture of the aortic intima, causing the blood in the cavity to enter the middle of the arterial wall. Without urgent and proper treatment, the mortality rate increases to 50% within 48 hours. Most patients present with acute onset of symptoms, including sudden severe pain and complex and variable clinical manifestations, which can be easily misdiagnosed. Despite this, the molecular mechanisms underlying AD are still unknown. Recently, non‐coding RNAs have emerged as novel regulators of gene expression. Previous studies have proven that ncRNAs can regulate several cardiovascular diseases; therefore, their potential as clinical biomarkers and novel therapeutic targets for AD has aroused widespread interest. To date, several studies have reported that microRNAs are crucially involved in AD progression. Additionally, several long non‐coding RNAs and circular RNAs have been found to be differentially expressed in AD samples, suggesting their potential roles in vascular physiology and disease. In this review, we discuss the functions of ncRNAs in AD pathophysiology and highlight their potential as biomarkers and therapeutic targets for AD. Meanwhile, we present the animal models previously used for AD research, as well as the specific methods for constructing mouse or rat AD models.

miR-145a Regulation of Pericyte Dysfunction in a Murine Model of Sepsis

BACKGROUND

Sepsis is a life-threatening systemic disease with severe microvascular dysfunction. Pericytes preserve vascular homeostasis. To our knowledge, the potential roles of microRNAs in sepsis-induced pericyte dysfunction have not been explored.

METHODS

We determined lung pericyte expression of miR-145a in cecal ligation and puncture (CLP)-induced sepsis. Mouse lung pericytes were isolated and transfected with a miR-145a mimic, followed by stimulation with lipopolysaccharide (LPS). We measured inflammatory cytokine levels. To assess the functions of miR-145a in vivo, we generated a pericyte-specific miR-145a-knockout mouse and determined sepsis-induced organ injury, lung and renal vascular leakage, and mouse survival rates. We used RNA sequencing and Western blotting to analyze the signaling pathways regulated by miR-145a.

RESULTS

CLP led to decreased miR-145a expression in lung pericytes. The miR-145a mimic inhibited LPS-induced increases in cytokines. In CLP-induced sepsis, pericytes lacking miR-145a exhibited increased lung and kidney vascular leakage and reduced survival rates. We found that miR-145a could suppress LPS-induced NF-κB activation. In addition, we confirmed that the transcription factor Friend leukemia virus integration 1 (Fli-1) is a target of miR-145a and that Fli-1 activates NF-κB signaling.

CONCLUSION

Our results demonstrated that pericyte miR-145a mediates sepsis-associated microvascular dysfunction, potentially by means of Fli-1-mediated modulation of NF-κB signaling.

Isoflavones and inflammatory bowel disease

Isoflavones constitute a class of plant hormones including genistein, daidzein, glycitein, formononetin, biochanin A, and irilone, and the major source of human intake is soybeans. Inflammatory bowel disease (IBD) is a chronic recurrent inflammatory disease including ulcerative colitis, Crohn’s disease, and indeterminate colitis, which seriously affects the quality of life of patients and has become a global health problem. Although the pathogenesis of IBD is not very clear, many factors are thought to be related to the occurrence and development of IBD such as genes, immunity, and intestinal flora. How to control IBD effectively for a long time is still a problem for gastroenterologists. Diet has an important effect on IBD. Patients with IBD should pay more attention to diet. To date, many studies have reported that isoflavones have both good and bad effects on IBD. Isoflavones have many activities such as regulating the inflammatory signal pathways and affecting intestinal barrier functions and gut flora. They can also act through estrogen receptors, as they have a similar structure to estrogen. Isoflavones are easy to get from diet for human. Whether they are valuable to be applied to the treatment of IBD is worth studying. This review summarizes the relationship between isoflavones and IBD.

The Kiwifruit Allergen Act d 1 Activates NF-κB Signaling and Affects mRNA Expression of TJ Proteins and Innate Pro-Allergenic Cytokines

Impairment of the intestinal barrier is one of the key events in the initiation of the sensitization process in food allergy. The aim of this study was to explore the effects of kiwifruit allergen Act d 1 on intestinal permeability and tight junction protein (TJP) gene expression in vivo and to explore its potential to activate the NF-ĸB signaling pathway and to regulate expression of epithelial pro-allergenic cytokines. Influences of Act d 1 on TJP gene expression and pro-allergenic cytokines in the mouse intestine was analyzed by qPCR upon allergen administration by oral gavage. The effect on the in vivo intestinal permeability was assessed in ELISA by measuring the translocation of β-lactoglobulin (BLG) into circulation. The capacity of Act d 1 to activate the NF-ĸB pathway was tested in HEK293 cells by fluorescent microscopy and flow cytometry. Administration of Actinidin (Act d 1) increased intestinal permeability to the BLG. This was accompanied by changes in gene expression of TJP mRNA and pro-allergenic cytokines IL-25, IL-33, and thymic stromal lymphopoietin (TSLP) compared to the control. Act d 1 reduced TEER of the HEK293 monolayer, was positive in an NF-ĸB-reporter HEK293 cell assay, and induced secretion of TSLP. These findings shed more light on the molecular events in the sensitization process of kiwifruit but possibly also of other protease food allergens.

Effect of Puerarin, Baicalin and Berberine Hydrochloride on the Regulation of IPEC-J2 Cells Infected with Enterotoxigenic Escherichia coli

Puerarin, baicalin and berberine hydrochloride are the main components of Gegen Qinlian Decoction, which has been used to treat diarrhoea in China for hundreds of years, yet the biological function and molecular mechanism of these components are not clear. To investigate the effects of puerarin, baicalin, and berberine hydrochloride on the regulation of porcine intestinal epithelial cells (IPEC-J2 cells) infected with enterotoxigenic Escherichia coli (ETEC). IPEC-J2 cells were pretreated with puerarin (200 μg/mL), baicalin (1 μg/mL), and berberine hydrochloride (100 μg/mL) at 37°C for 3 h and then coincubated with the F4ac ETEC bacterial strain 200 at 37°C for 3 h. ETEC infection damaged the structure of IPEC-J2 cells, upregulated mucin 4 (P < 0.01) and mucin 13 mRNA (P < 0.05) expression, increased the apoptosis rate (P < 0.05), and promoted inflammatory responses (IL-6 and CXCL-2 mRNA expression) in IPEC-J2 cells by activating the nuclear factor-κB (NF-κB) signaling pathway. Pretreatment with puerarin, baicalin, and berberine hydrochloride improved the structure and morphology of IPEC-J2 cells and inhibited ETEC adhesion by downregulating specific adhesion molecules. Pretreatment with baicalin decreased the inflammatory response; pretreatment with baicalin and berberine hydrochloride decreased the inflammatory response mediated by the NF-κB signaling pathway. Pretreatment with puerarin, baicalin, and berberine hydrochloride protected IPEC-J2 cells from ETEC infection by inhibiting bacterial adhesion and inflammatory responses.

Potential of Omega-3 Polyunsaturated Fatty Acids in Managing Chemotherapy- or Radiotherapy-Related Intestinal Microbial Dysbiosis

Chemotherapy- or radiotherapy-related intestinal microbial dysbiosis is one of the main causes of intestinal mucositis. Cases of bacterial translocation into peripheral blood and subsequent sepsis occur as a result of dysfunction in the intestinal barrier. Evidence from recent studies depicts the characteristics of chemotherapy- or radiotherapy-related intestinal microbial dysbiosis, which creates an imbalance between beneficial and harmful bacteria in the gut. Decreases in beneficial bacteria can lead to a weakening of the resistance of the gut to harmful bacteria, resulting in robust activation of proinflammatory signaling pathways. For example, lipopolysaccharide (LPS)-producing bacteria activate the nuclear transcription factor-κB signaling pathway through binding with Toll-like receptor 4 on stressed epithelial cells, subsequently leading to secretion of proinflammatory cytokines. Nevertheless, various studies have found that the omega-3 (n-3) polyunsaturated fatty acids (PUFAs) such as docosahexaenoic acid and eicosapentaenoic acid can reverse intestinal microbial dysbiosis by increasing beneficial bacteria species, including Lactobacillus, Bifidobacterium, and butyrate-producing bacteria, such as Roseburia and Coprococcus. In addition, the n-3 PUFAs decrease the proportions of LPS-producing and mucolytic bacteria in the gut, and they can reduce inflammation as well as oxidative stress. Importantly, the n-3 PUFAs also exert anticancer effects in colorectal cancers. In this review, we summarize the characteristics of chemotherapy- or radiotherapy-related intestinal microbial dysbiosis and introduce the contributions of dysbiosis to the pathogenesis of intestinal mucositis. Next, we discuss how n-3 PUFAs could alleviate chemotherapy- or radiotherapy-related intestinal microbial dysbiosis. This review provides new insights into the clinical administration of n-3 PUFAs for the management of chemotherapy- or radiotherapy-related intestinal microbial dysbiosis.

SRT1720 ameliorates sodium taurocholate-induced severe acute pancreatitis in rats by suppressing NF-κB signalling

Severe acute pancreatitis (SAP) is a medical emergency that is often associated with multiple organ failure and high mortality. Although an SAP diagnosis requires prompt treatment, therapeutic options remain limited. SRT1720 is a newly formulatedSIRT1 activator that exerts multiple pharmacological activities with beneficial health effects. However, its potential as an SAP treatment has not been explored. The current study assessed the effect of SRT1720 on a rat model of sodium taurocholate-induced SAP and explored the underlying mechanism. SAP was induced in rats by retrograde injection of a 3.5% sodium taurocholate solution (1 ml/kg) in the biliopancreatic duct. SRT1720 (5 mg/kg) was administered intraperitoneally after sodium taurocholate exposure. Serum samples were analysed for inflammatory cytokine levels and select enzymatic activities using the enzyme-linked immunosorbent assay and commercial enzyme activity assay kits, respectively; protein expression levels were evaluated by western blotting; mRNA levels of biomarkers were determined by quantitative real-time PCR; histopathological changes were analysed by haematoxylin and eosin staining and immunohistochemistry.SRT1720 treatment significantly reduced serum amylase, lipase, pancreatic histological scores, proinflammatory cytokine (TNF-α and IL-6) levels, and expression of NF-κB and p65 in sodium taurocholate-induced SAP rats. Importantly, the treatment stimulated SIRT1 and IκBα levels in pancreatic tissue. Our data suggest that SRT1720 protects rats from sodium taurocholate-induced SAP by suppressing the NF-κB signalling pathway.

Cardiotrophin-1 attenuates experimental colitis in mice

Cardiotrophin-1 (CT-1) holds potent anti-inflammatory, cytoprotective, and anti-apoptotic effects in the liver, kidneys, and heart. In the present study, the role of endogenous CT-1 and the effect of exogenous CT-1 were evaluated in experimental ulcerative colitis. Colitis was induced in CT-1 knockout and wild-type (WT) mice by administration of dextran sulphate sodium (DSS) in the drinking water during 7 days. CT-1 knockout mice showed higher colon damage and disease severity than WT mice. In addition, CT-1 (200 µg/kg/day, iv) or vehicle (as control) was administered during 3 days to WT, colitic mice, starting on day 4 after initiation of DSS. Disease activity index (DAI), inflammatory markers (tumor necrosis factor α (TNF-α), INFγ, IL-17, IL-10, inducible nitric oxide synthase (iNOS)), colon damage, apoptosis (cleaved caspase 3), nuclear factor κB (NFκB) and STAT-3 activation, and bacterial translocation were measured. Compared with mice treated with DSS, mice also treated with exogenous CT-1 showed lower colon damage, DAI, plasma levels of TNFα, colon expression of TNF-α, INFγ, IL-17, iNOS and cleaved caspase 3, higher NFκB and signal transducer and activator of transcription 3 (STAT3) pathways activation, and absence of bacterial translocation. We conclude that endogenous CT-1 plays a role in the defense and repair response of the colon against ulcerative lesions through an anti-inflammatory and anti-apoptotic effect. Supplementation with exogenous CT-1 ameliorates disease symptoms, which opens a potentially new therapeutic strategy for ulcerative colitis.

Augmenter of liver regeneration (ALR) regulates acute pancreatitis via inhibiting HMGB1/TLR4/NF-κB signaling pathway

This research aimed to explore the effect of augmenter of liver regeneration (ALR) in acute pancreatitis (AP) of mice and the underlying mechanism. Caerulein were given to mice to get AP models. AP mice were given saline, ALR plasmids or negative control plasmids. Then, pancreas tissues were fixed and stained for histological examination. The levels of serum amylase, serum lipase, MPO, HMGB1, TNF-α, IL-1β as well as MCP-1 were detected by ELISA assay. The mRNA levels of TLR4, p65, IκBα, iNOS, COX-2 and GAPDH were examined by RT-qPCR. The protein levels of HMGB1, TLR4, MD2, MyD88, IκBα and GAPDH were detected by western blotting. ALR decreased serum amylase as well as lipase levels and alleviated the histopathological alterations of the pancreas in AP mice. ALR decreased the MPO activity of pancreas in AP Mice. ALR decreased the HMGB1/TLR4 signaling pathway in AP Mice. ALR decreased pancreas IL-1β and MCP-1 in AP mice, and also decreased plasma TNF-α and IL-1β in AP mice. ALR attenuated the cerulein-caused increase in p65 mRNA and protein levels, but had no effects on mRNA and protein levels of IκBα. The AP mice significantly promoted the mRNA levels of iNOS and COX-2 that was inhibited by ALR. HNE formation was also increased in AP mice, but it was decreased by ALR. ALR alleviates acute pancreatitis by inhibiting HMGB1/TLR4/NF-κB signaling pathway. It is promising to alleviate the syndromes of patients with acute via targeting ALR.

Isoastragaloside I inhibits NF-κB activation and inflammatory responses in BV-2 microglial cells stimulated with lipopolysaccharide

The excessive activation of microglia in many neurodegenerative diseases is detrimental to neuronal survival. Isoastragaloside I (ISO I) is a natural saponin molecule found within the roots of Astragalus membranaceus, a famous traditional Chinese medicine. In the present study, the anti‑inflammatory effects and the mechanisms of action of ISO I on activated BV-2 cells stimulated with lipopolysaccharide (LPS) were investigated. ISO I dose‑dependently inhibited the excessive release of nitric oxide (NO) and tumor necrosis factor (TNF)-α in the LPS-stimulated BV-2 cells. Moreover, it decreased the production of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2), and mitigated the gene expression of interleukin (IL)-1β, TNF-α and iNOS induced by LPS. Further experiments revealed that ISO I decreased the phosphorylation levels of nuclear factor-κB (NF-κB), and suppressed its nuclear translocation and transactivation activity. In addition, it inhibited the activation of signaling pathway molecules, such as PI3K, Akt and mitogen-activated protein kinases (MAPKs). Taken together, our findings suggest that ISO I prevents LPS-induced microglial activation probably by inhibiting the activation of the NF-κB via PI3K/Akt and MAPK signaling pathways, indicating its therapeutic potential for neurological diseases relevant to neuroinflammation.

Impact of Novel Sorghum Bran Diets on DSS-Induced Colitis

We have demonstrated that polyphenol-rich sorghum bran diets alter fecal microbiota; however, little is known regarding their effect on colon inflammation. Our aim was to characterize the effect of sorghum bran diets on intestinal homeostasis during dextran sodium sulfate (DSS)-induced colitis. Male Sprague-Dawley rats (N = 20/diet) were provided diets containing 6% fiber from cellulose, or Black (3-deoxyanthocyanins), Sumac (condensed tannins) or Hi Tannin Black (both) sorghum bran. Colitis was induced (N = 10/diet) with three separate 48-h exposures to 3% DSS, and feces were collected. On Day 82, animals were euthanized and the colon resected. Only discrete mucosal lesions, with no diarrhea or bloody stools, were observed in DSS rats. Only bran diets upregulated proliferation and Tff3, Tgfβ and short chain fatty acids (SCFA) transporter expression after a DSS challenge. DSS did not significantly affect fecal SCFA concentrations. Bran diets alone upregulated repair mechanisms and SCFA transporter expression, which suggests these polyphenol-rich sorghum brans may suppress some consequences of colitis.

Identification and application of anti-inflammatory compounds screening system based on RAW264.7 cells stably expressing NF-κB-dependent SEAP reporter gene

BACKGROUND

NF-κB is one of the key transcription factors in the inflammatory response, transactivates a series of pro-inflammatory genes and is therefore regarded as an important target for anti-inflammatory drug screening.

METHOD

We recombined the reporter gene vector with inserting the "neo" transcript into the vector pNF-κB-SEAP, made the reporter gene vector stable in a eukaryotic cell line. The recombinant reporter gene vector we named pNF-κB-SEAP-Neo was transfected into RAW264.7. We selected the transfected RAW264.7 cell line with G418 for 15 days and then get RAW264.7 cells stably expressing NF-κB-dependent SEAP named as RAW264.7-pNF-κB-SEAP cells. We treated the RAW264.7-pNF-κB-SEAP cells with NF-κB agonists as LPS, PolyI:C and TNF-α, NF-κB inhibitor as PDTC and BAY117085, in different concentrations and time points and tested the expression of the SEAP, constructed the drug screening system on the base of the RAW264.7-pNF-κB-SEAP cell line. 130 chemicals were screened with the drug screening system we constructed and one of these chemicals numbered w10 was found could inhibit the NF-κB significantly. At last, we verified the inhibition of w10 to expression of genes promoted with NF-κB in HepG2 and Hela, and to migration of Hela.

RESULT

In this study, we established a drug screening system based on RAW264.7 cells that stably expressed the NF-κB-dependent, SEAP reporter gene. To develop a standard method for drug screening using this reporter-gene cell line, the test approach of SEAP was optimized and basic conditions for drug screening were chosen. This included the initial cell number inoculated in a 96-well plate, the optimum agonist, inhibitor of NF-κB pathway and their concentrations during screening. Subsequently, 130 newly synthesized compounds were screened using the stable reporter-gene cell line. The anti-inflammatory effects of the candidate compounds obtained were further verified in 2 cancer cell lines. The results indicated that compound W10 (methyl 4-(4-(prop-2-yn-1-ylcarbamoyl) phenylcarbamoyl) benzoate) significantly inhibited SEAP production under the screening conditions. Further results confirmed that the precursor compound significantly inhibited the transcription of NF-κB target genes.

CONCLUSION

In conclusion, RAW264.7 cells, stably expressing the NF-κB-dependent SEAP-reporter gene, may provide a new, feasible, and efficient cellular drug-screening system.

Immunomodulation of monocytes by probiotic and selected lactic Acid bacteria

Some lactic acid bacteria (LAB), especially bacteria belonging to the genus Lactobacillus, are recognized as common inhabitants of the human gastrointestinal tract and have received considerable attention in the last decades due to their postulated health-promoting effects. LAB and probiotic bacteria can modulate the host immune response. However, much is unknown about the mediators and mechanisms responsible for their immunological effect. Here, we present a study using cytokine secretion from the monocytic cell line THP-1 and NF-κB activation in the monocytic cell line U937-3xkB-LUC to elucidate immune stimulating abilities of LAB in vitro. In this study, we investigate both commercially available and potential probiotic LAB strains, and the role of putative surface proteins of L. reuteri using mutants. L. reuteri strains induced the highest cytokine secretion and the highest NF-κB activation, whereas L. plantarum strains and L. rhamnosus GG were low inducers/activators. One of the putative L. reuteri surface proteins, Hmpref0536_10802, appeared to be of importance for the stimulation of THP-1 cells and the activation of NF-κB in U937-3xkB-LUC cells. Live and UV-inactivated preparations resulted in different responses for two of the strains investigated. Our results add to the complexity in the interaction between LAB and human cells and suggest the possible involvement of secreted pro- and anti-inflammatory mediators of LAB. It is likely that it is the sum of bacterial surface proteins and bacterial metabolites and/or secreted proteins that induce cytokine secretion in THP-1 cells and activate NF-κB in U937-3xkB-LUC cells in this study.

A novel anti-inflammatory role of GPR120 in intestinal epithelial cells

GPR120 (free fatty acid receptor-4) is a G protein-coupled receptor for medium- and long-chain unsaturated fatty acids, including ω-3 fatty acids. Recent studies have shown GPR120 to play cardinal roles in metabolic disorders via modulation of gut hormone secretion and insulin sensitivity and to exert anti-inflammatory effects in macrophages and adipose tissues. However, information on anti-inflammatory role of GPR120 at the level of intestinal epithelium is very limited. Current studies demonstrated differential levels of GPR120 mRNA and protein along the length of the human, mouse, and rat intestine and delineated distinct anti-inflammatory responses following GPR120 activation in model human intestinal epithelial Caco-2 cells, but not in model mouse intestinal epithelial endocrine cell line STC-1. In Caco-2 cells, GPR120 was internalized, bound to β-arrestin-2, and attenuated NF-κB activation in response to 30-min exposure to the agonists GW9508, TUG-891, or docosahexaenoic acid. These effects were abrogated in response to small interfering RNA silencing of β-arrestin-2. Treatment of STC-1 cells with these agonists did not induce receptor internalization and had no effects on NF-κB activation, although treatment with the agonists GW9508 or TUG-891 for 6 h augmented the synthesis and secretion of the gut hormone glucagon-like peptide-1 in this cell line. Our studies for the first time demonstrated a GPR120-mediated novel anti-inflammatory pathway in specific intestinal epithelial cell types that could be of therapeutic relevance to intestinal inflammatory disorders.

Treatment with Mesna and n-3 polyunsaturated fatty acids ameliorates experimental ulcerative colitis in rats

Oxidative damage is a central feature of ulcerative colitis. Here, we tested whether the antioxidant Mesna, when administered alone or in combination with n-3 polyunsaturated fatty acids (n-3 PUFAs), affects the outcome of dextran sodium sulphate (DSS)-induced ulcerative colitis in rats. After the induction of colitis, DSS-treated rats were further treated orally (p.o), intraperitoneally (i.p) or intrarectally (i.r) for either 7 or 14 days with Mesna, n-3 PUFAs or both. Rats were euthanized at the end of each treatment period. Clinical disease activity index was recorded throughout the experiment. At necropsy colorectal gross lesions were scored. Colitis was scored histologically, and the expression of myeloperoxidase (MPO), caspase-3, inducible nitric oxide synthase (iNOS) and nuclear factor κB (NF-κΒ) in colonic tissue was assessed by immunohistochemistry. Mesna alone was sufficient to significantly reduce colorectal tissue damage when administered orally or intraperitoneally. Orally coadministered n-3 PUFAs enhanced this effect, resulting in the significant suppression of DSS colitis after 7 days, and a remarkable recovery of colorectal mucosa was evident after 14 days of treatment. The amelioration of colon pathology co-existed with a significant decrease in MPO expression, overexpression of iNOS and reduction of nuclear NF-κB p65 in inflammatory cells, and the suppression of apoptosis in colonic epithelial cells. The simultaneous administration of Mesna and n-3 PUFAs is particularly effective in ameliorating DSS colitis in rats, by reducing oxidative stress, inflammation and apoptosis, probably through a mechanism that involves the inhibition of NF-κB and overexpression of iNOS.

TLR4-mediated NF-κB signaling pathway mediates HMGB1-induced pancreatic injury in mice with severe acute pancreatitis

Severe acute pancreatitis (SAP) is an extremely dangerous acute abdominal disorder which causes multiple complications and has a high mortality rate. Previous research has suggested that high-mobility group box 1 (HMGB1) plays an important role in the pathogenesis of SAP; however, the mechanisms underlying this strong correlation remain unclear. In this study, to further investigate whether HMGB1 acts as a stimulating factor, and whether Toll-like receptor 4 (TLR4) acts as its major mediator in the development of pancreatic injury during SAP, recombinant human HMGB1 (rhHMGB1) and TLR4-deficient mice were used. We found that HMGB1 and TLR4 were highly expressed, and nuclear factor-κB (NF-κB) was activated in our mouse model of SAP. We noted that the rhHMGB1 pancreas-targeted injection activated the TLR4-mediated NF-κB signaling pathway and induced pancreatic injury in wild-type mice. In TLR4-deficient mice, the rhHMGB1-induced activation of NF-κB and pathological changes in the pancreas were less evident than in wild-type mice. Therefore, this study provides evidence that HMGB1 promotes the pathogenesis of pancreatitis, and its downstream TLR4-mediated NF-κB signaling pathway is a potential important mediator in the development of this form of pancreatic injury.

Extracellular Vesicles Derived from Bone Marrow Mesenchymal Stem Cells Protect against Experimental Colitis via Attenuating Colon Inflammation, Oxidative Stress and Apoptosis

The administration of bone mesenchymal stem cells (BMSCs) could reverse experimental colitis, and the predominant mechanism in tissue repair seems to be related to their paracrine activity. BMSCs derived extracellular vesicles (BMSC-EVs), including mcirovesicles and exosomes, containing diverse proteins, mRNAs and micro-RNAs, mediating various biological functions, might be a main paracrine mechanism for stem cell to injured cell communication. We aimed to investigate the potential alleviating effects of BMSC-EVs in 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis model. Intravenous injection of BMSC-EVs attenuated the severity of colitis as evidenced by decrease of disease activity index (DAI) and histological colonic damage. In inflammation response, the BMSC-EVs treatment significantly reduced both the mRNA and protein levels of nuclear factor kappaBp65 (NF-κBp65), tumor necrosis factor-alpha (TNF-α), induciblenitric oxidesynthase (iNOS) and cyclooxygenase-2 (COX-2) in injured colon. Additionally, the BMSC-EVs injection resulted in a markedly decrease in interleukin-1β (IL-1β) and an increase in interleukin-10 (IL-10) expression. Therapeutic effect of BMSC-EVs associated with suppression of oxidative perturbations was manifested by a decrease in the activity of myeloperoxidase (MPO) and Malondialdehyde (MDA), as well as an increase in superoxide dismutase (SOD) and glutathione (GSH). BMSC-EVs also suppressed the apoptosis via reducing the cleavage of caspase-3, caspase-8 and caspase-9 in colitis rats. Data obtained indicated that the beneficial effects of BMSC-EVs were due to the down regulation of pro-inflammatory cytokines levels, inhibition of NF-κBp65 signal transduction pathways, modulation of anti-oxidant/ oxidant balance, and moderation of the occurrence of apoptosis.

Protective effect of glutamine on intestinal injury and bacterial community in rats exposed to hypobaric hypoxia environment

AIM: To investigate the protective effect of glutamine (Gln) on intestinal injury and the bacterial community in rats exposed to hypobaric hypoxia environment.

METHODS: Sprague-Dawley rats were divided into control, hypobaric hypoxia (HH), and hypobaric hypoxia + Gln (5.0 g/kg BW·d) (HG) groups. On the first 3 d, all rats were placed in a normal environment. After the third day, the HH and HG groups were transferred into a hypobaric chamber at a simulated elevation of 7000 m for 5 d. The rats in the HG group were given Gln by gavage daily for 8 d. The rats in the control and HH groups were treated with the same volume of saline. The intestinal morphology, serum levels of malondialdehyde (MDA), superoxide dismutase (SOD), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-gamma (IFN-γ) and diamino oxidase (DAO) were examined. We also evaluated the expression levels of occludin, toll-like receptor 4 (TLR4), nuclear factor-κB p65 (NF-κB p65) and myeloid differentiation factor 88 (MyD88), and examined the bacterial community in caecal contents.

RESULTS: Hypobaric hypoxia induced the enlargement of the heart, liver, lung and kidney, and caused spleen atrophy. Intestinal villi damage was also observed in the HH group. Supplementation with Gln significantly alleviated hypobaric-induced damage to main organs including the intestine, increased serum SOD (1.14 ± 0.03 vs 0.88 ± 0.04, P < 0.05) and MDA (8.35 ± 1.60, P < 0.01) levels and decreased serum IL-6 (1172.13±30.49 vs 1407.05 ± 34.36, P < 0.05), TNF-α (77.46 ± 0.78 vs 123.70 ± 3.03, P < 0.001), IFN-γ (1355.42 ± 72.80 vs 1830.16 ± 42.07, P < 0.01) and DAO (629.30 ± 9.15 vs 524.10 ± 13.34, P < 0.001) levels. Moreover, Gln significantly increased occludin (0.72 ± 0.05 vs 0.09 ± 0.01, P < 0.001), TLR4 (0.15 ± 0.05 vs 0.30 ±0.09, P < 0.05), MyD88 (0.32 ± 0.08 vs 0.71 ± 0.06, P < 0.01), and NF-κB p65 (0.16 ± 0.04 vs 0.44 ± 0.03, P < 0.01) expression levels and improved the intestinal bacterial community.

CONCLUSION: Gln treatment protects from intestinal injury and regulates the gut flora imbalance in hypoxia environment. These effects may be related to the TLR4/MyD88/NF-κB signaling pathway.

Remote ischemic preconditioning as treatment for non-ischemic gastrointestinal disorders: Beyond ischemia-reperfusion injury

Common gastrointestinal diseases such as radiation enteritis (RE), acute pancreatitis, inflammatory bowel diseases (IBD) and drug-induced hepatotoxicity share pathophysiological mechanisms at the molecular level, mostly involving the activation of many pathways of the immune response, ultimately leading to tissue injury. Increased oxidative stress, inflammatory cytokine release, inflammatory cell infiltration and activation and the up-regulation of inflammatory transcription factors participate in the pathophysiology of these complex entities. Treatment varies in each specific disease, but at least in the cases of RE and IBD immunosuppressors are effective. However, full therapeutic responses are not always achieved. The pathophysiology of ischemia-reperfusion (IR) injury shares many of these mechanisms. Brief and repetitive periods of ischemia in an organ or limb have been shown to protect against subsequent major IR injury in distant organs, a phenomenon called remote ischemic preconditioning (RIP). This procedure has been shown to protect the gut, pancreas and liver by modulating many of the same inflammatory mechanisms. Since RIP is safe and tolerable, and has shown to be effective in some recent clinical trials, I suggest that RIP could be used as a physiologically relevant adjunct treatment for non-ischemic gastrointestinal inflammatory conditions.

Short-chain fatty acids activate GPR41 and GPR43 on intestinal epithelial cells to promote inflammatory responses in mice

BACKGROUND & AIMS

Short-chain fatty acids (SCFAs), the most abundant microbial metabolites in the intestine, activate cells via G-protein-coupled receptors (GPRs), such as GPR41 and GPR43. We studied regulation of the immune response by SCFAs and their receptors in the intestines of mice.

METHODS

Inflammatory responses were induced in GPR41(-/-), GPR43(-/-), and C57BL6 (control) mice by administration of ethanol; 2, 4, 6-trinitrobenzene sulfonic-acid (TNBS); or infection with Citrobacter rodentium. We examined the effects of C rodentium infection on control mice fed SCFAs and/or given injections of antibodies that delay the immune response. We also studied the kinetics of cytokine and chemokine production, leukocyte recruitment, intestinal permeability, and T-cell responses. Primary colon epithelial cells were isolated from GPR41(-/-), GPR43(-/-), and control mice; signaling pathways regulated by SCFAs were identified using immunohistochemical, enzyme-linked immunosorbent assay, and flow cytometry analyses.

RESULTS

GPR41(-/-) and GPR43(-/-) mice had reduced inflammatory responses after administration of ethanol or TNBS compared with control mice, and had a slower immune response against C rodentium infection, clearing the bacteria more slowly. SCFAs activated intestinal epithelial cells to produce chemokines and cytokines in culture and mice after administration of ethanol, TNBS, or C rodentium. These processes required GPR41 and GPR43 and were required to recruit leukocytes and activate effector T cells in the intestine. GPR41 and GPR43 activated extracellular signal-regulated kinase 1/2 and p38 mitogen-activated protein kinase signaling pathways in epithelial cells to induce production of chemokines and cytokines during immune responses.

CONCLUSIONS

SCFAs activate GPR41 and GPR43 on intestinal epithelial cells, leading to mitogen-activated protein kinase signaling and rapid production of chemokines and cytokines. These pathways mediate protective immunity and tissue inflammation in mice.

Iron-metabolic function and potential antibacterial role of Hepcidin and its correlated genes (Ferroportin 1 and Transferrin Receptor) in turbot (Scophthalmus maximus)

Antimicrobial peptide plays an important role in fish immunity. The small molecular antimicrobial peptide Hepcidin in turbot was studied and reported in this paper. The Ferroportin 1 (FPN1) and Transferrin Receptor (TFR) genes, which are related to Hepcidin, were cloned in turbot. The characteristics of Hepcidin and its related genes were studied, including an analysis of the expression patterns and cloning of the Hepcidin promoter, the relationship between Hepcidin and NF-κB and the regulation of iron-metabolism. The results showed that the promoter of SmHepcidin contains the binding sites of NF-κB, and NF-κB may directly or indirectly receive feedback signals from SmHepcidin. In the liver, spleen and kidney, in which there was an increased SmHepcidin expression level, SmFPN1 dramatically decreased and SmTFR was also either decreased or exhibited no obvious change after bacterial/viral infection and an injection of exogenous Hepcidin protein. RNAi experiments in turbot kidney cells confirmed the expression changes of these gene patterns. Furthermore, the administration of exogenous Hepcidin protein, which regulates the level of chelatable iron in cells, further confirmed the function of Hepcidin in iron metabolism. It is speculated that the rapidly increased expression of SmHepcidin may induce changes in the expression of related genes, and that the in vivo chelatable iron concentration which participates in the antibacterial process was also changed when exogenous pathogens are present in turbot. It is suggested that SmHepcidin plays a defensive role against pathogenic infection.

Role of TLR4/NF-κB in damage to intestinal mucosa barrier function and bacterial translocation in rats exposed to hypoxia

The role of Toll-like receptor 4 (TLR4)/nuclear factor-kappa-B (NF-κB) in intestinal mucosal barrier damage and bacterial translocation under hypoxic exposure is unclear. Here, we investigated their role using an acute hypobaric hypoxia model. Adult Sprague-Dawley rats were divided into control (C), hypoxia (H), hypoxia+NF-κB inhibitor pyrrolidinedithiocarbamic acid (PDTC) (100 mg. kg) (HP), hypoxia+0.5 mg/kg lipopolysaccharide (HPL), and hypoxia+PDTC+LPS (HPL) group. Except control group, other four groups were placed in a hypobaric chamber set at 7000 m. Samples were collected at 72 h after pressure reduction. Damage in ultrastructure of the intestinal tract was examined by transmission electron microscopy and bacterial translocation was detected by cultivation. Kinetic turbidimetric assay was used to measure the serum LPS.

ELISA was performed to detect TNF-α and IL-6 serum concentrations. Fluorescent quantitative RT-PCR was used to measure TLR4 mRNA levels was measured using quantitative RT-PCR and protein of NF-κB p65 was measured by western blotting. Different degrees of intestinal mucosa damage were observed in groups H and HL. The damage was significantly alleviated after blockage of the TLR4/NF-κB signaling pathway. PDTC- treatment also reversed hyoxia- and LPS-induced bacterial translocation rate and increased serum levels of LPS, TNF-α, and IL-6. TLR4 mRNA levels and NF-κB p65 expression were consistent with the serum factor results. This study suggested that TLR4 and NF-κB expression increased in rat intestinal tissues after acute hypoxia exposure. PDTC-treatment reversed TLR4 and NF-κB upregulation and alleviated damage to the intestinal tract and bacterial translocation. Thus, the TLR4/NF-κB signaling pathway may be critical to the mechanism underlying hypoxia-induced damage to intestinal barrier function and bacterial translocation.

Paeoniflorin suppresses the expression of intercellular adhesion molecule-1 (ICAM-1) in endotoxin-treated human monocytic cells

BACKGROUND AND PURPOSE

Paeoniflorin (PF) has ameliorative effects on learning and memory impairment and cerebral ischaemia in rats and has protective effects against the degeneration of dopaminergic neurons in substantia nigra. The neuroprotective effects of PF are most probably derived from its anti-inflammatory property. Abnormally high levels of intercellular adhesion molecule-1 (ICAM-1) have been found to be associated with a wide range of inflammatory and immune responses. Here we studied whether PF regulates the levels of ICAM-1 elevated in LPS-activated differentiated human monocytic U937 cells and TNF-α-stimulated human umbilical vein endothelial cells (HUVECs).

EXPERIMENTAL APPROACH

mRNA levels were evaluated by RT-PCR. Protein levels were evaluated by Western blot analysis. An immunofluorescence technique was used to estimate NF-κB translocation, and NF-κB binding to nuclear DNA was determined by EMSA.

KEY RESULTS

PF inhibited ICAM-1 expression elevated in LPS-induced U937 cells and TNF-α-stimulated HUVECs. Although previous reports showed that PF's action is mediated by activating adenosine A₁ receptors, application of a selective adenosine A₁ receptor antagonist did not change the inhibitory effect of PF in our experiments. To elucidate the underlying mechanisms of the effect of PF, we studied its effect on signalling pathways upstream of ICAM-1 expression. PF suppressed the activation of the NF-κB pathway, which regulates the expression of ICAM-1. The TLR4 and MAPK pathways were shown not to be involved in the effects of PF in these cells.

CONCLUSIONS AND IMPLICATIONS

PF inhibits ICAM-1 expression in LPS-treated U937 cells and TNF-α-stimulated HUVECs by suppressing the activation of the NF-κB pathway.

The amphioxus genome provides unique insight into the evolution of immunity

Immune systems evolve as essential strategies to maintain homeostasis with the environment, prevent microbial assault and recycle damaged host tissues. The immune system is composed of two components, innate and adaptive immunity. The former is common to all animals while the latter consists of a vertebrate-specific system that relies on somatically derived lymphocytes and is associated with near limitless genetic diversity as well as long-term memory. Deuterostome invertebrates provide a view of immune repertoires in phyla that immediately predate the origins of vertebrates. Genomic studies in amphioxus, a cephalochordate, have revealed homologs of genes encoding most innate immune receptors found in vertebrates; however, many of the gene families have undergone dramatic expansions, greatly increasing the innate immune repertoire. In addition, domain-swapping accounts for the innovation of new predicted pathways of receptor function. In both amphioxus and Ciona, a urochordate, the VCBPs (variable region containing chitin-binding proteins), which consist of immunoglobulin V (variable) and chitin binding domains, mediate recognition through the V domains. The V domains of VCBPs in amphioxus exhibit high levels of allelic complexity that presumably relate to functional specificity. Various features of the amphioxus immune repertoire reflect novel selective pressures, which likely have resulted in innovative strategies. Functional genomic studies underscore the value of amphioxus as a model for studying innate immunity and may help reveal how unique relationships between innate immune receptors and both pathogens and symbionts factored in the evolution of adaptive immune systems.

Steroid receptor coactivator-3 differentially regulates the inflammatory response in peritoneal macrophages

Steroid receptor coactivator-3 (SRC-3) is a transcriptional coactivator that plays an important role in the regulation of cytokine mRNA translation. In the present study, SCR-3 gene knockout mice were used to study the effects of SCR-3 on the regulation of the inflammatory response in peritoneal macrophages induced by lipopolysaccharides (LPS). Peritoneal macrophages (PMs) of SRC-3^−/− mice showed a decrease in the release of TNF-α, IL-1β and IL-6, and an increase in the release of IL-10. Furthermore, results of RT-PCR also showed that levels of TNF-α, IL-1β and IL-6 mRNA expression were significantly lower, while the level of IL-10 mRNA expression was higher in the SRC-3^−/− mice, compared to those of wild-type mice, following treatment with LPS (p<0.01). In addition, western blotting revealed that: i) the extent of reduction of the glucocorticoid receptor in PMs from SRC-3^−/− mice was significantly lower than that in wild-type mice (p<0.01); ii) the extent of increase of AP-1 in PMS from SRC-3^−/− mice was significantly lower than that in wild-type mice (p<0.01); iii) the extent of increase of NF-κB p65 in PMs from SRC-3^−/− mice was significantly higher than that in wild-type mice (p<0.01). Collectively, our studies revealed that SRC-3 may play a key role in the maintenance of innate immunity. Furthermore, absence of the SRC-3 protein may result in the partial loss of inflammation and phagocytosis barrier function, including suppression of LPS-induced transcriptional activity, release of TNF-α, IL-1β and IL-6, and obstruction of the function of phagocytes and elimination of bacteria, as well as their production.

Pathways analysis of molecular markers in chronic sinusitis with polyps

OBJECTIVE

To perform a comprehensive molecular pathways analysis of genes identified through genome-wide expression profiling and the published literature for chronic sinusitis with polyps.

STUDY DESIGN

Molecular pathways analysis.

SETTING

Academic medical center.

METHODS

A molecular pathways analysis of gene biomarkers discovered through hypothesis-driven and high-throughput molecular studies was performed. Genes identified with a PubMed literature search were analyzed with Ingenuity Pathways Analysis software to identify central molecules implicated in the pathogenesis of chronic sinusitis with polyps. The central pathways were then compared with those identified through genome-wide expression profiling of ethmoid polyps.

RESULTS

A total of 97 molecules were investigated with Ingenuity Pathways Analysis based on 55 studies that evaluated differences in gene expression (39), genetic variation (12), or proteomics (4). The analysis revealed 9 statistically significant molecular networks containing central nodes that included transcription factors, protein kinases, cytokines, and growth factors/receptors. The highest scoring networks implicated nuclear factor kappa-B, tumor necrosis factor, and mitogen-activated protein kinases. The majority of pathways in the literature review analysis overlapped with those identified through a single genome-wide expression study.

CONCLUSIONS

Chronic sinusitis with polyps is a complex disease with suspected contribution of multiple genetic and environmental factors. The search for causative genes has led to the discovery of numerous candidates. Pathways analysis applied to these candidate genes identified common central molecules that are likely to be key mediators of the disease process. Novel therapies targeting these molecules may be applicable for the treatment of chronic sinusitis with polyps.

The intestinal microbiota and chronic disorders of the gut

Mucosal surfaces of the gut are colonized by large numbers of heterogeneous bacteria that contribute to intestinal health and disease. In genetically susceptible individuals, a 'pathogenic community' may arise, whereby abnormal gut flora contributes to alterations in the mucosa and local immune system leading to gastrointestinal disease. These diseases include enteric infections, such as Clostridium difficile infection, small intestinal bacterial overgrowth, functional gastrointestinal disorders (including IBS), IBD and colorectal cancer. Prebiotics, probiotics and synbiotics (a combination of prebiotics and probiotics) have the capacity to reverse pathologic changes in gut flora and local immunity. Intestinal health and disease need to be thoroughly characterized to understand the interplay between the indigenous microbiota, the immune system and genetic host factors. This Review provides a broad overview of the importance of the intestinal microbiota in chronic disorders of the gut.

New paradigms in chronic intestinal inflammation and colon cancer: role of melatonin

In intestinal bowel disease (IBD), immune-mediated conditions exert their effects through various cells and proinflammatory mediators. Recent data support a participation of the endoplasmic reticulum stress and mitochondrial dysfunctions in IBD. Moreover, it is evident that chronic degenerative pathologies, including IBD, share comparable disease mechanisms with alteration in the autophagy mechanisms. Chronic inflammation in IBD exposes these patients to a number of signals known to have tumorigenic effects. This circuitry of inflammation and cancer modifies apoptosis and autophagy, and promotes cellular cycle progression, invasion, and angiogenesis. Melatonin has been shown as a specific antioxidant reducing oxidative damage in both lipid and aqueous cell environments. However, several studies provide further insight into the molecular mechanisms of melatonin action in the colon. In this line, recent data suggest that melatonin modulates autophagy and sirtuin activity. An anti-autophagic property of melatonin has been demonstrated, and it could contribute to its anti-oncogenic activity. Nevertheless, there is no information about whether antitumoral effects of melatonin on colon cancer are dependent on autophagy. Sirtuins have pleiotropic effects on cancer development, being reported both as facilitator and as suppressor of colon cancer development. Sirtuins and melatonin are connected through the circadian clock machinery, and melatonin seems able to correct the alterations in sirtuin activity associated with several pathological conditions. Autophagy and sirtuin activities are linked through 5'AMP-activated protein kinase (AMPK) activation, which switches on autophagy and increases sirtuin. The effect of melatonin on AMPK and the impact of this effect on IBD and colon cancer remain an open question.

The regulation of thymic stromal lymphopoietin in gut immune homeostasis

Thymic stromal lymphopoietin is a novel IL-7-like cytokine that exerts immunomodulatory effects and is constitutively expressed by intestinal epithelial cells in response to commensal bacteria colonization. Thymic stromal lymphopoietin can directly or indirectly promote Th2 and Treg responses, and is believed to inhibit Th1 and Th17 responses and limit the expression of proinflammatory cytokines such as IL-17 and IFN-γ. In response to infection by enteric pathogens, intestinal epithelial cells upregulate thymic stromal lymphopoietin expression in order to generate balance between inflammation and immune clearance. Recently, however, aberrant expression of thymic stromal lymphopoietin has been associated with inflammatory bowel disease. Thus, we sought to examine the relationship between the TLSP-TSLPR pathway and inflammation in hopes of contributing to the search for a novel therapeutic target to treat a variety of inflammatory diseases, including inflammatory bowel disease.

Enterocyte death and intestinal barrier maintenance in homeostasis and disease

The intestinal epithelium is the largest surface area of the body in contact with the external environment. This specialized single cell layer is constantly renewed and is a physical barrier that separates intestinal microbiota from underlying tissues, preventing bacterial infiltration and subsequent inflammation. Specialized secretory epithelial cell types such as Paneth cells and goblet cells limit bacterial adhesion and infiltration by secreting antibacterial peptides and mucins, respectively. Rapid cell renewal coincides with apical exfoliation of 'old' enterocytes without compromising epithelial barrier integrity. When the intestinal epithelium is inflamed barrier integrity can be compromised, due to uncontrolled death of enterocytes allowing bacterial infiltration. This review discusses the different mechanisms which regulate or affect intestinal barrier integrity under homeostatic and inflammatory conditions.

[Barrier- and autophagic functions of the intestinal epithelia: role of disturbances in the pathogenesis of Crohn's disease]

Crohn's disease is a widely known debilitating chronic inflammatory disease, mostly affecting terminal ileum and/or colon. Epidemiological, familial and twin studies suggest that genetic factors play an important role in susceptibility to the disease. Clinical observations suggest that ill-defined environmental factors also play a part. Advances in molecular genotyping technology, statistical methodologies, bioinformatics and the combined use of them in genome wide scanning and association studies resulted in the identification of more than 30 susceptibility genes and loci associated with Crohn's disease and revealed and highlighted a number of new previously unsuspected pathways playing a role in the pathogenesis of Crohn's disease. Close association of the disease with polymorphisms in the genes encoding the pattern recognition receptors particularly the NOD2 protein, the Wnt pathway transcription factor Tcf4 (also known as TCFL2) and the autophagic regulator ATG16L1 have been found. The polymorphisms involved are associated with decreased defensin production (defensin deficiency) which can lead to changes in the composition of the commensal microbial flora, defects in the intestinal barrier functions and bacterial invasion of the mucosa. Other recently recognized consequences of the polymorphisms involving the genes encoding NOD2 and ATG16L1 proteins are that the truncated NOD2 protein is unable to induce autophagy and this protein, just like the ATG16L1 T300A mutant protein, leads to failure adequately to destroy phagocytosed bacteria. The consequence is persisting low level infection, chronic intestinal inflammation, tissue injury and the clinical symptoms of the disease. Thus, Crohn's disease can be seen to be caused by defects in the innate immune defense, in particular defects in bacterial processing and clearance. The accumulated evidence suggests that Crohn's disease is associated with an exaggerated adaptive immune response to the persisting intestinal microbes in genetically susceptible hosts. Intervention in these circumstances should probably be geared to strengthening of the innate immune responses rather than simple attempts to suppress adaptive immunity.