Do we really understand what the immunological disturbances in inflammatory bowel disease mean?

Lactobacillus acidophilus inhibits the TNF-α-induced increase in intestinal epithelial tight junction permeability via a TLR-2 and PI3K-dependent inhibition of NF-κB activation

Background

Defective intestinal epithelial tight junction (TJ), characterized by an increase in intestinal TJ permeability, has been shown to play a critical role in the pathogenesis of inflammatory bowel disease (IBD). Tumor necrosis factor-α (TNF-α) is a key pro-inflammatory cytokine involved in the immunopathology of IBD and has been shown to cause an increase in intestinal epithelial TJ permeability. Although TNF-α antibodies and other biologics have been advanced for use in IBD treatment, these therapies are associated with severe side effects and have limited efficacy, and there is an urgent need for therapies with benign profiles and high therapeutic efficacy. Probiotic bacteria have beneficial effects and are generally safe and represent an important class of potential therapeutic agents in IBD. Lactobacillus acidophilus (LA) is one of the most used probiotics for wide-ranging health benefits, including in gastrointestinal, metabolic, and inflammatory disorders. A specific strain of LA, LA1, was recently demonstrated to have protective and therapeutic effects on the intestinal epithelial TJ barrier. However, the mechanisms of actions of LA1 remain largely unknown.

Methods

The primary aim of this study was to investigate microbial-epithelial interactions and novel signaling pathways that regulate the effect of LA1 on TNF-α-induced increase in intestinal epithelial TJ permeability, using cell culture and animal model systems.

Results and Conclusion

Pre-treatment of filter-grown Caco-2 monolayers with LA1 prevented the TNF-α-induced increase in intestinal epithelial TJ permeability by inhibiting TNF-α-induced activation of NF-κB p50/p65 and myosin light chain kinase (MLCK) gene and kinase activity in a TLR-2-dependent manner. LA1 produced a TLR-2- and MyD88-dependent activation of NF-κB p50/p65 in immune cells; however, LA1, in intestinal cells, inhibited the NF-κB p50/p65 activation in a TLR-2-dependent but MyD88-independent manner. In addition, LA1 inhibition of NF-κB p50/p65 and MLCK gene was mediated by TLR-2 pathway activation of phosphatidylinositol 3-kinase (PI3K) and IKK-α phosphorylation. Our results demonstrated novel intracellular signaling pathways by which LA1/TLR-2 suppresses the TNF-α pathway activation of NF-κB p50/p65 in intestinal epithelial cells and protects against the TNF-α-induced increase in intestinal epithelial TJ permeability.

Targeted Application of Functional Foods as Immune Fitness Boosters in the Defense against Viral Infection

In recent times, the emergence of viral infections, including the SARS-CoV-2 virus, the monkeypox virus, and, most recently, the Langya virus, has highlighted the devastating effects of viral infection on human life. There has been significant progress in the development of efficacious vaccines for the prevention and control of viruses; however, the high rates of viral mutation and transmission necessitate the need for novel methods of control, management, and prevention. In recent years, there has been a shift in public awareness on health and wellbeing, with consumers making significant dietary changes to improve their immunity and overall health. This rising health awareness is driving a global increase in the consumption of functional foods. This review delves into the benefits of functional foods as potential natural means to modulate the host immune system to enhance defense against viral infections. We provide an overview of the functional food market in Europe and discuss the benefits of enhancing immune fitness in high-risk groups, including the elderly, those with obesity, and people with underlying chronic conditions. We also discuss the immunomodulatory mechanisms of key functional foods, including dairy proteins and hydrolysates, plant-based functional foods, fermentates, and foods enriched with vitamin D, zinc, and selenium. Our findings reveal four key immunity boosting mechanisms by functional foods, including inhibition of viral proliferation and binding to host cells, modulation of the innate immune response in macrophages and dendritic cells, enhancement of specific immune responses in T cells and B cells, and promotion of the intestinal barrier function. Overall, this review demonstrates that diet-derived nutrients and functional foods show immense potential to boost viral immunity in high-risk individuals and can be an important approach to improving overall immune health.

Analysis of Killer Cell Immunoglobulin-Like Receptor Genes and Their HLA Ligands in Inflammatory Bowel Diseases

Genetic studies have illustrated that killer cell immunoglobulin-like receptor (KIR) genes could participate in various autoimmune disorders. We aimed to clarify the role of KIR genes, HLA ligands, HLA-KIR interactions, and their genotypes in inflammatory bowel disease (IBD) susceptibility. The study population was composed of 183 IBD subjects, comprising 100 ulcerative colitis (UC) patients, 83 Crohn's disease (CD) patients, and 274 healthy subjects. Polymerase chain reaction with sequence-specific primers (PCR-SSP) was used to evaluate the absence or presence of the 15 KIR genes, 5 HLA class I ligands, and 2 pseudogenes. We did not find any significant difference in allele frequency of KIRs and pseudogenes between IBD patients and healthy controls. In the case of HLA genes, there was a significant difference in HLA-B-Bw4Thr80 frequency between UC patients and healthy controls (P = 0.03, OR = 0.06, 95%CI = 0.008-0.4). Furthermore, we found a significant difference in HLA-C1Asn80 frequency between CD patients and healthy controls (P = 0.04, OR = 0.49, 95% CI = 0.3-0.8). In the full-array combination of KIR genes, there was no significant frequency difference between UC patients and healthy controls, while two KIR genotypes showed a significant susceptible association with CD. Our data do not support a strong role of NK cells in IBD susceptibility, but it does not rule out a role for KIR variability in IBD patients. However, there are some protective associations such as Bw4 alleles; these associations may be due to the interaction of the alleles to TCRs rather than KIRs.

Bioelectric neuromodulation for gastrointestinal disorders: effectiveness and mechanisms

The gastrointestinal tract has extensive, surgically accessible nerve connections with the central nervous system. This provides the opportunity to exploit rapidly advancing methods of nerve stimulation to treat gastrointestinal disorders. Bioelectric neuromodulation technology has considerably advanced in the past decade, but sacral nerve stimulation for faecal incontinence currently remains the only neuromodulation protocol in general use for a gastrointestinal disorder. Treatment of other conditions, such as IBD, obesity, nausea and gastroparesis, has had variable success. That nerves modulate inflammation in the intestine is well established, but the anti-inflammatory effects of vagal nerve stimulation have only recently been discovered, and positive effects of this approach were seen in only some patients with Crohn's disease in a single trial. Pulses of high-frequency current applied to the vagus nerve have been used to block signalling from the stomach to the brain to reduce appetite with variable outcomes. Bioelectric neuromodulation has also been investigated for postoperative ileus, gastroparesis symptoms and constipation in animal models and some clinical trials. The clinical success of this bioelectric neuromodulation therapy might be enhanced through better knowledge of the targeted nerve pathways and their physiological and pathophysiological roles, optimizing stimulation protocols and determining which patients benefit most from this therapy.

The Bisindole Alkaloid Caulerpin, from Seaweeds of the Genus Caulerpa, Attenuated Colon Damage in Murine Colitis Model

Caulerpin (CLP), an alkaloid from algae of the genus Caulerpa, has shown anti-inflammatory activity. Therefore, this study aimed to analyze the effect of CLP in the murine model of peritonitis and ulcerative colitis. Firstly, the mice were submitted to peritonitis to evaluate which dose of CLP (40, 4, or 0.4 mg/kg) could decrease the inflammatory infiltration in the peritoneum. The most effective doses were 40 and 4 mg/kg. Then, C57BL/6 mice were submitted to colitis development with 3% dextran sulfate sodium (DSS) and treated with CLP at doses of 40 and 4 mg/kg. The disease development was analyzed through the disease activity index (DAI); furthermore, colonic tissue samples were submitted to histological analysis, NFκB determination, and in vitro culture for cytokines assay. Therefore, CLP at 4 mg/kg presented the best results, triggering improvement of DAI and attenuating the colon shortening and damage. This dose was able to reduce the TNF-α, IFN-γ, IL-6, IL-17, and NFκB p65 levels, and increased the levels of IL-10 in the colon tissue. Thus, CLP mice treatment at a dose of 4 mg/kg showed promising results in ameliorating the damage observed in the ulcerative colitis.

The Immunological Basis of Inflammatory Bowel Disease

Inflammatory bowel diseases (IBDs) are chronic ailments, Crohn's disease and ulcerative colitis being the most important. These diseases present an inflammatory profile and they differ according to pathophysiology, the affected area in the gastrointestinal tract, and the depth of the inflammation in the intestinal wall. The immune characteristics of IBD arise from abnormal responses of the innate and adaptive immune system. The number of Th17 cells increases in the peripheral blood of IBD patients, while Treg cells decrease, suggesting that the Th17/Treg proportion plays an important role in the development and maintenance of inflammation. The purpose of this review was to determine the current state of knowledge on the immunological basis of IBD. Many studies have shown the need for further explanation of the development and maintenance of the inflammatory process.

Degree of colitis correlates with microbial composition and cytokine responses in colon and caecum of Gαi2-deficient mice

An altered immune response and gut microbiota have been associated with the pathology of inflammatory bowel diseases (IBDs). However, there is limited knowledge of how inflammation is associated with changes in the microbiota. We studied the microbiota in the intestine and faeces as well as the cytokine gene expressions in caecum and colon of a mouse model (Gαi2(-/-)) of colitis, and analysed them in relation to the degrees of inflammation in the colon. The degree of colitis was associated with general changes in the complexity of the microbiota and was corroborated by quantitative analyses of the Bacteroides and Lactobacillus High gene expression levels of IL-17 and IFN-γ in colon and caecum were detected in Gαi2(-/-) mice with moderate and severe colitis. High IL-27 gene expression in the colon of mice with moderate and severe colitis and in the caecum of mice with moderate colitis was also detected. Negative correlations between IL-27 and Bacteroides and Lactobacillus and between IFN-γ and Lactobacillus were detected in caecum. This research indicates that the degree of colitis in IBD correlates with the gene expression of cytokines and with disturbances in the gut microbiota. Furthermore, the caecum could have an important role in the pathology of IBD.

Anti-inflammatory activity of fruit fractions in vitro, mediated through toll-like receptor 4 and 2 in the context of inflammatory bowel disease

Pattern recognition receptors such as Toll-Like Receptor 2 (TLR2) and 4 (TLR4) are important in detecting and responding to stress and bacterial stimuli. Defect or damage in the TLR2 and TLR4 pathways can lead to sustained inflammation, characteristic of inflammatory bowel disease (IBD). The goal of this study was to identify fruit fractions that can be tested further to develop them as complementary therapies for IBD. In order to do this, we identified fruit fractions that mediate their anti-inflammatory response through the TLR4 and TLR2 pathway. Human Embryonic Kidney (HEK)-hTLR4 and hTLR2 cells were stimulated with their respective ligands to induce inflammation. These cells were treated with one of the 12 fractionated fruits and the inflammatory effect measured. 10 of the fruits came up as anti-inflammatory in the hTLR4 assay and nine in the hTLR2 assays. Many of the fruit fractions mediated their anti-inflammatory actions either mainly in their hydrophobic fractions (such as elderberry) or hydrophilic fractions (such as red raspberry), or both. The strongest anti-inflammatory effects were seen for feijoa and blackberry. This study shows that fruits can have multiple fractions eliciting anti-inflammatory effects in a pathway specific manner. This suggests that the compounds found in fruits can act together to produce health benefits by way of reducing inflammation. Exploiting this property of fruits can help develop complimentary therapies for inflammatory diseases.

Anti-inflammatory activity of traditional Chinese medicinal herbs

Accumulating epidemiological and clinical evidence shows that inflammation is an important risk factor for various human diseases. Thus, suppressing chronic inflammation has the potential to delay, prevent, and control various chronic diseases, including cerebrovascular, cardiovascular, joint, skin, pulmonary, blood, lymph, liver, pancreatic, and intestinal diseases. Various natural products from traditional Chinese medicine (TCM) have been shown to safely suppress proinflammatory pathways and control inflammation-associated disease. In vivo and/or in vitro studies have demonstrated that anti-inflammatory effects of TCM occur by inhibition of the expression of master transcription factors (for example, nuclear factor-κB (NF-κB)), pro-inflammatory cytokines (for example, tumor necrosis factor-α (TNF-α), chemokines (for example, chemokine (C-C motif) ligand (CCL)-24), intercellular adhesion molecule expression and pro-inflammatory mediators (for example, inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX2)). However, a handful of review articles have focused on the anti-inflammatory activities of TCM and explore their possible mechanisms of action. In this review, we summarize recent research attempting to identify the anti-inflammatory constituents of TCM and their molecular targets that may create new opportunities for innovation in modern pharmacology.

Inflammatory bowel disease and demyelination: more than just a coincidence?

Infliximab and other anti-TNF-α agents have been implicated for drug-induced demyelination in patients with inflammatory bowel diseases (IBDs). We evaluated existing data from MEDLINE and EMBASE and conducted a narrative review to investigate further the aforementioned association. Our literature search highlighted 34 case reports, 3 case-control studies, 1 prospective and 7 retrospective cohort studies published in English. Available data suggest that IBD patients can manifest demyelinating events in both central and peripheral nervous system, however, they are still insufficient to conclude whether anti-TNF-α therapies are an independent risk factor for demyelination. Prospective cohort studies with internal control groups are needed to estimate the true incidence of demyelinating disorders in patients with IBD and to elucidate if anti-TNF-α therapy increases further the risk of demyelination.

Protective effect of quercetin against acetic acid induced inflammatory bowel disease (IBD) like symptoms in rats: possible morphological and biochemical alterations

BACKGROUND

Inflammatory bowel disease (IBD) is characterized by most common symptoms such as rectal bleeding. Lack of specific, curative treatments tempted us to evaluate the therapeutic efficacy of quercetin against acetic acid induced IBD like symptoms.

METHODS

Animals were randomly divided into five groups (n = 6): naive, control, sulphasalazine and quercetin, and were pretreated for three days. Colitis was induced by intra-rectal administration of 3% acetic acid.

RESULTS

Pretreatment with sulphasalazine or quercetin significantly attenuated the biochemical and morphological alterations in the colon induced by acetic acid in rats.

CONCLUSIONS

The findings of the study suggest the possible role of quercetin as therapeutics in IBD.

Serological markers of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an intestinal inflammatory disease of unknown etiology with two main distinguishable entities, Crohn's disease (CD) and ulcerative colitis (UC). Current diagnosis of IBD relies on the clinical, endoscopic, radiological, histological and biochemical features, but these approaches have shortcomings, especially in cases of overlapping symptoms of CD and UC. The detection of serological markers can improve the diagnosis of IBD, because an aberrant immune response against microbial or endogenous antigens in a genetically susceptible host seems to be implicated in IBD pathogenesis. Current evidence suggests that the detection of serum immunology markers is useful in differential diagnosis of CD versus UC and can be a valuable aid in stratifying patients according to disease phenotype and risk of complications.

Enhanced blood lymphocytes apoptosis in children with inflammatory bowel disease

The aim of this work was to measure peripheral lymphocyte apoptosis during IBD flare and remission. Subjects and Methods. Flow-cytometric assessment of apoptosis of peripheral blood lymphocytes (PBL) was assessed in 30 children with IBD (16 with ulcerative colitis and 14 with Crohn's disease) compared to 22, age and sex matched, healthy children. This was carried out during a flare, whether in newly diagnosed or relapsing patients, and after achievement of remission. Clinical findings, complete blood count, liver transaminases, and kidney functions were assessed. Results. Early apoptotic and late apoptotic/necrotic lymphocytes were significantly higher during IBD flare compared to controls (P ≤ 0.01 and <0.01, resp., in ulcerative colitis and P ≤ 0.01 and <0.01, resp., in Crohn's disease patients). Remission values were significantly decreased but did not come back to the control levels. Early apoptotic values were significantly related to joint involvement in IBD patients (P < 0.0001). Conclusions. We can speculate a systemic nature of IBD as evident by enhanced peripheral lymphocyte apoptosis. This is related, to a great extent, to the disease process as it is more deranged in flare than in remission. Relation of this derangement to extraintestinal manifestations needs a special attention.

Serological markers of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a heterogeneous group of chronic inflammatory disorders of the gastrointestinal tract with two main distinguishable entities, Crohn’s disease (CD) and ulcerative colitis (UC). IBD-unclassified (IBD-U) is a diagnosis that covers the “grey” zone of diagnostic uncertainty between UC and CD. Current diagnosis of IBD relies on the clinical, endoscopic, radiological, histological and biochemical features, but this approach has shortcomings especially in cases of overlapping symptoms of CD and UC. The need for a diagnostic tool that would improve the conventional methods in IBD diagnosis directed the search towards potential immunological markers, since an aberrant immune response against microbial or endogenous antigens in a genetically susceptible host seems to be implicated in IBD pathogenesis. The spectrum of antibodies to different microbial antigens and autoantibodies associated with IBD is rapidly expanding. Most of these antibodies are associated with CD like anti-glycan antibodies: anti-Saccharomices cerevisiae (ASCA) and the recently described anti-laminaribioside (ALCA), anti-chitobioside (ACCA), anti-mannobioside (AMCA), anti-laminarin (anti-L) and anti-chitin (anti-C) antibodies; in addition to other antibodies that target microbial antigens: anti-outer membrane porin C (anti-OmpC), anti-Cbir1 flagellin and anti-I2 antibody. Also, autoantibodies targeting the exocrine pancreas (PAB) were shown to be highly specific for CD. In contrast, UC has been associated with anti-neutrophil cytoplasmic autoantibodies (pANCA) and antibodies against goblet cells (GAB). Current evidence suggests that serologic panels of multiple antibodies are useful in differential diagnosis of CD versus UC and can be a valuable aid in stratifying patients according to disease phenotype and risk of complications.

Intestinal anti-inflammatory activity of red wine extract: unveiling the mechanisms in colonic epithelial cells

The development of new therapeutic approaches, combining efficacy and safety against intestinal inflammation, notably inflammatory bowel disease (IBD), has emerged as an important goal due to the significant side effects and the lack of effectiveness of standard current therapies. Recently, several studies described the health-promoting effects of red wine, including anti-inflammatory properties, but the molecular mechanisms underlying its beneficial role remain largely unknown. Red wine is rich in phenolic compounds and it has been suggested that the positive effect of red wine intake might be attributed not only to the antioxidant properties of these compounds but also to the modulation of signalling cascades in connection with physiological and pathophysiological conditions such as inflammatory processes. This study assesses the potential anti-inflammatory action of a red wine extract (RWE) enriched in polyphenols in a cellular model of intestinal inflammation using cytokines-stimulated HT-29 colon epithelial cells. RWE suppressed cytokines-induced IκB degradation and interleukin-8 production in a dose-dependent manner. Coherently, key inflammatory mediators downstream NF-κB activation; notably cyclooxygenase-2 and inducible nitric oxide synthase were maintained at low levels by RWE in the presence of the cytokines. Additionally, RWE inhibited both the increase of nitric oxide derived from iNOS and of protein tyrosine nitration, a biomarker of nitrosative stress that typically requires the reaction of nitric oxide with the superoxide radical. Taken together, the anti-inflammatory action of RWE, mechanistically supported by the modulation of cascades orchestrated by NF-κB and involving nitric oxide, suggests that RWE (a readily straightforward preparation when compared with the purification of specific compounds) may represent a simple and inexpensive therapeutic strategy in the context of intestinal inflammation.

MIF as a disease target: ISO-1 as a proof-of-concept therapeutic

Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine that has been implicated as playing a causative role in many disease states, including sepsis, pneumonia, diabetes, rheumatoid arthritis, inflammatory bowel disease, psoriasis and cancer. To inhibit the enzymatic and biologic activities of MIF, we and others have developed small-molecule MIF inhibitors. Most MIF inhibitors bind within the hydrophobic pocket that contains highly conserved amino acids known to be essential for MIF's proinflammatory activity. The best characterized of these small-molecule MIF inhibitors, (S,R)-3-(4-hydroxyphenyl)-4,5-dihydro-5-isoxazole acetic acid methyl ester (ISO-1) has been validated in scores of laboratories worldwide. Like neutralizing anti-MIF antibodies, ISO-1 significantly improves survival and reduces disease progression and/or severity in multiple murine models where MIF is implicated. This MIF inhibitor, its derivatives and other MIF-targeted compounds show great promise for future testing in disease states where increased MIF activity has been discovered.

Beneficial effects of treatment with transglutaminase inhibitor cystamine on the severity of inflammation in a rat model of inflammatory bowel disease

Inflammatory bowel disease (IBD) represents a socially and clinically relevant disorder, characterized by intestinal chronic inflammation. Cystamine (CysN) is a multipotent molecule with healthy effects and, moreover, it is an inhibitor of transglutaminases (TGs), including the TG type 2 (TG2), an enzyme with pleiotropic functions, involved in different pathways of inflammation and central in the pathogenesis of some human disorders as the IBD. Our aim was to evaluate the effect of CysN in an IBD rat model. A total of 30 rats were divided into 4 groups: controls without treatment (CTR; n=7); receiving the 2,4,6-trinitrobenzene sulfonic acid enema (TNBS group; n=8); treated with TNBS enema plus oral CysN (TNBS-CysN group; n=8); treated with CysN (CysN group; n=7). After killing, bowel inflammation was evaluated applying specific scores. TG activity, TG2 and isopeptide bond immunohistochemical expression, and tumor necrosis factor-α (TNF-α) were evaluated in the colonic tissue, such as interleukin-6 (IL-6) serological levels (ELISA). TG2 was also evaluated on the luminal side of the colon by immunoautoradiography. Colonic samples from IBD patients were compared with animal results. TNBS-CysN group developed a less severe colitis compared with the TNBS group (macroscopic score 0.43±0.78 vs 3.28±0.95, microscopic score 6.62±12.01 vs 19.25±6.04, P<0.05, respectively) associated with a decrease of TG activity, TG2 and isopeptide bond immunohistochemical expression, TNF-α and IL-6 levels. No statistically significant differences were found between CysN and CTR groups. The colonic immunolocalization of TG2 was comparable in humans affected by IBD and TNBS-administered animals. This is the first demonstration that treatment with a CysN has an anti-inflammatory effect, reducing severity of colitis in a rat model. CysN could be tested as a possible treatment or co-treatment in IBD therapeutic trials.

Inflammatory bowel disease and hepatitis B and C in Western Balkans: a referral centre study and review of the literature

BACKGROUND AND AIMS

There is limited data on IBD patients diagnosed with viral hepatitis B and C. The aim of the study was to assess the prevalence of chronic HBV or HCV infection in IBD patients followed by our centre and to describe and review the course of bowel and liver disease during therapy.

METHODS

Single centre retrospective study on 482 consecutive IBD patients. Laboratory investigation for HBV and HCV was performed with routine methods. Treatment protocols for HBV included IFNa and nucleot(s)ide administration and for HCV combined IFNa and ribavirin.

RESULTS

We diagnosed 15 patients (15/482, 3.1%) with HBV or HCV. Of these, 11 were HBV (11/482, 2.3%) and 4 were HCV (4/482, 0.8%). Nine of eleven HBV patients received antiviral therapy (8 lamivudine, 1 IFNa). Five lamivudine patients were switched to tenofovir and in another one adefovir dipivoxil were added. Bowel disease was in remission in ten of the eleven HBV patients. One patient was diagnosed with carcinoid tumor. Two HCV patients received IFNa that was well tolerated. One HCV patient denied therapy and one died from hepatocellular cancer. Of the seven patients on azathioprine only one achieved sustained response. Four patients on Infliximab achieved bowel disease remission but experienced biochemical or virological flare.

CONCLUSIONS

This study demonstrates that prevalence of HBV and HCV infection in a large IBD cohort from Western Balkans is compared to that of the background population. IBD patients under immunosuppressants may apparently be treated with safety if preventive antiviral treatment is administered.

Endoplasmic reticulum stress-activated C/EBP homologous protein enhances nuclear factor-kappaB signals via repression of peroxisome proliferator-activated receptor gamma

Endoplasmic reticulum (ER) stress is a causative factor of inflammatory bowel diseases. ER stress mediators, including CCAAT enhancer-binding protein (C/EBP) homologous protein (CHOP), are elevated in intestinal epithelia from patients with inflammatory bowel diseases. The present study arose from the question of how chemical ER stress and CHOP protein were associated with nuclear factor-κB (NF-κB)-mediated epithelial inflammatory response. In a human intestinal epithelial cell culture model, chemical ER stresses induced proinflammatory cytokine interleukin-8 (IL-8) expression and the nuclear translocation of CHOP protein. CHOP was positively involved in ER-activated IL-8 production and was negatively associated with expression of peroxisome proliferator-activated receptor γ (PPARγ). ER stress-induced IL-8 production was enhanced by NF-κB activation that was negatively regulated by PPARγ. Mechanistically, ER stress-induced CHOP suppressed PPARγ transcription by sequestering C/EBPβ and limiting availability of C/EBPβ binding to the PPARγ promoter. Due to the CHOP-mediated regulation of PPARγ action, ER stress can enhance proinflammatory NF-κB activation and maintain an increased level of IL-8 production in human intestinal epithelial cells. In contrast, PPARγ was a counteracting regulator of gut inflammatory response through attenuation of NF-κB activation. The collective results support the view that balances between CHOP and PPARγ are crucial for epithelial homeostasis, and disruption of these balances in mucosal ER stress can etiologically affect the progress of human inflammatory bowel diseases.

Effect of overweight on gastrointestinal microbiology and immunology: correlation with blood biomarkers

A cross-sectional study was carried out in order to compare intestinal microbiological and immunological biomarkers with blood glucose and lipids, satiety-related hormones and inflammatory biomarkers characterising differences between obese and normal weight subjects. Faecal and blood samples were obtained from twenty obese subjects with an average BMI of 32·9 kg/m2and twenty normal weight subjects with an average BMI of 23·3 kg/m2. Blood insulin, TAG and leptin were significantly elevated, whereas concentrations of HDL and ghrelin were significantly decreased in the obese subjects. Inflammatory status in the obese subjects was characterised by a trend for elevated blood C-reactive protein (CRP;P = 0·06) and IL-6 (P = 0·02). The faecal microbial composition differed between the groups; less sulphate-reducing bacteria (P = 0·05) and a trend for lessBacteroides(P = 0·07) were measured for overweight subjects. Furthermore, an inverse correlation was demonstrated between faecalBacteroideslevels and waist circumference (P = 0·05). The faecal microbial metabolites differed between the groups; increased concentrations of branched-chain fatty acids, phenolics, valeric acid, di- and hydroxy acids were described in the obese subjects. No differences between the measured intestinal inflammatory biomarkers were detected. However, systemic inflammation (CRP and IL-6) was correlated with the faecal concentrations of phenolics and lactic acid (P < 0·05 and 0·05, andP < 0·01 and 0·05, respectively). In summary, weight-related differences were observed both in the intestinal microbial composition and its activity. The role of intestinal signals, such as phenolics and lactic acid in the development of weight-related problems, needs to be studied further.

PTEN loss induces epithelial--mesenchymal transition in human colon cancer cells

BACKGROUND

The epithelial-mesenchymal transition is a critical early event in the invasion and metastasis of many types of cancer, including colorectal cancer (CRC). Chronic inflammation is an inducer of several cancer types and inflammatory cytokines have been implicated in tumor invasion.

MATERIALS AND METHODS

Human colon cancer cell lines HCT116 and SW480 were transfected with phosphatase and tensin homolog deleted on chromosome 10 (PTEN) siRNA or non-targeting control (NTC). Invasiveness was measured using a modified Boyden chamber assay and migration was assessed using a scratch assay.

RESULTS

PTEN knockdown increased the invasion and migration of CRC cells and the addition of medium containing tumor necrosis factor-alpha (TNF-alpha) further enhanced the migration and invasion. PTEN knockdown resulted in nuclear beta-catenin accumulation and increased expression of downstream proteins c-Myc and cyclin D1.

CONCLUSION

Our study supports the findings of clinical studies identifying an association of PTEN loss with late stage cancer. Cellular factors secreted from the surrounding tumor milieu likely act in concert with genetic changes in the tumor cells and contribute to enhanced tumor invasion.

Anti-inflammatory action of mollugin and its synthetic derivatives in HT-29 human colonic epithelial cells is mediated through inhibition of NF-kappaB activation

Mollugin is the active compound of Rubia cordifolia, which has been used as a traditional Chinese medicine for the treatment of various inflammatory diseases including arthritis and uteritis. In the present study, we investigated for the first time the inhibitory effects and the mechanisms of action of mollugin (M1) and its synthetic derivatives (M2-M4) on tumor necrosis factor (TNF)-alpha-induced inflammatory responses in HT-29 human colon epithelial cells. Treatment with M1 and its derivatives M2-M4 significantly inhibited TNF-alpha-induced attachment of U937 monocytic cells to HT-29 cells, which mimics the initial phase of colon inflammation. TNF-alpha-induced mRNA induction of the chemokines, monocyte chemoattractant protein (MCP)-1 and interleukin (IL)-8, and the intercellular cell adhesion molecule (ICAM)-1, which are involved in adhesion between leukocytes and epithelial cells, was suppressed by M1-M4, and M1 was the most efficacious. In addition, M1-M4 significantly suppressed TNF-alpha-induced NF-kappaB transcriptional activity. Such NF-kappaB inhibitory activity of M1-M4 (20 microM) correlated with their ability to suppress TNF-alpha-induced chemokine expression and U937 monocytic cell adhesion to HT-29 colonic epithelial cells. Treatment of HT-29 cells with M1 and PDTC, a NF-kappaB inhibitor, synergistically suppressed both TNF-alpha-induced NF-kappaB activation and monocytic cell adhesion to HT-29 cells. These results suggest that M1-M4 inhibit TNF-alpha-induced expression of inflammatory molecules via NF-kappaB, and that M1, a potent NF-kappaB inhibitor, may be a valuable new drug candidate for the treatment of colon inflammation.