Involvement of IL-6 in the pathogenesis of inflammatory bowel disease and colon cancer

Pro-Inflammatory Cytokines Trigger the Overexpression of Tumour-Related Splice Variant RAC1B in Polarized Colorectal Cells

Simple Summary

Tumours are now known to develop more quickly when the tumour cell mass is located in a tissue that shows signs of chronic inflammation. Under such conditions, inflammatory cells from the surrounding tumour microenvironment provide survival signals to which cancer cells respond. We have previously found that some colorectal tumours overexpress the protein RAC1B that sustains tumour cell survival. Here we used a colon mucosa-like in vitro cell model and found that the presence of cancer-associated fibroblasts and pro-inflammatory macrophages stimulated colorectal cells to increase their RAC1B levels. Under these conditions, the secreted survival signals were analysed, and interleukin-6 identified as the main trigger for the increase in RAC1B levels. The results contribute to understand the tumour-promoting effect of inflammation at the molecular level.

Abstract

An inflammatory microenvironment is a tumour-promoting condition that provides survival signals to which cancer cells respond with gene expression changes. One example is the alternative splicing variant Rat Sarcoma Viral Oncogene Homolog (Ras)-Related C3 Botulinum Toxin Substrate 1 (RAC1)B, which we previously identified in a subset of V-Raf Murine Sarcoma Viral Oncogene Homolog B (BRAF)-mutated colorectal tumours. RAC1B was also increased in samples from inflammatory bowel disease patients or in an acute colitis mouse model. Here, we used an epithelial-like layer of polarized Caco-2 or T84 colorectal cancer (CRC) cells in co-culture with fibroblasts, monocytes or macrophages and analysed the effect on RAC1B expression in the CRC cells by RT-PCR, Western blot and confocal fluorescence microscopy. We found that the presence of cancer-associated fibroblasts and M1 macrophages induced the most significant increase in RAC1B levels in the polarized CRC cells, accompanied by a progressive loss of epithelial organization. Under these conditions, we identified interleukin (IL)-6 as the main trigger for the increase in RAC1B levels, associated with Signal Transducer and Activator of Transcription (STAT)3 activation. IL-6 neutralization by a specific antibody abrogated both RAC1B overexpression and STAT3 phosphorylation in polarized CRC cells. Our data identify that pro-inflammatory extracellular signals from stromal cells can trigger the overexpression of tumour-related RAC1B in polarized CRC cells. The results will help to understand the tumour-promoting effect of inflammation and identify novel therapeutic strategies.

The role of the mitochondrial protein VDAC1 in inflammatory bowel disease: a potential therapeutic target

Recent studies have implicated mitochondrial dysfunction as a trigger of inflammatory bowel diseases, including Crohn's disease (CD) and ulcerative colitis (UC). We have investigated the role of the mitochondria gate-keeper protein, the voltage-dependent-anion channel 1 (VDAC1), in gastrointestinal inflammation and tested the effects of the newly developed VDAC1-interacting molecules, VBIT-4 and VBIT-12, on UC induced by dextran sulfate sodium (DSS) or trinitrobenzene sulphonic acid (TNBS) in mice. VDAC1, which controls metabolism, lipids transport, apoptosis, and inflammasome activation, is overexpressed in the colon of CD and UC patients and DSS-treated mice. VBIT-12 treatment of cultured colon cells inhibited the DSS-induced VDAC1 overexpression, oligomerization, and apoptosis. In the DSS-treated mice, VBIT-12 suppressed weight loss, diarrhea, rectal bleeding, pro-inflammatory cytokine production, crypt and epithelial cell damage, and focal inflammation. VBIT-12 also inhibited the infiltration of inflammatory cells, apoptosis, mtDNA release, and activation of caspase-1 and NRLP3 inflammasome to reduce the inflammatory response. The levels of the ATP-gated P2X7-Ca2+/K+ channel and ER-IP3R-Ca2+ channel, and of the mitochondrial anti-viral protein (MAVS), mediating NLRP3 inflammasome assembly and activation, were highly increased in DSS-treated mice, but not when VBIT-12 treated. We conclude that UC may be promoted by VDAC1-overexpression and may therefore be amenable to treatment with novel VDAC1-interacting molecules. This VDAC1-based strategy exploits a completely new target for UC treatment and opens a new avenue for treating other inflammatory/autoimmune diseases.

Advances in the treatment of inflammatory bowel disease: Focus on polysaccharide nanoparticulate drug delivery systems

The complex pathogenesis of inflammatory bowel disease (IBD) explains the several hurdles for finding an efficient approach to cure it. Nowadays, therapeutic protocols aim to reduce inflammation during the hot phase or maintain remission during the cold phase. Nonetheless, these drugs suffer from severe side effects or poor efficacy due to low bioavailability in the inflamed region of the intestinal tract. New protocols based on antibodies that target proinflammatory cytokines are clinically relevant. However, besides being expensive, their use is associated with a primary nonresponse or a loss of response following a long administration period. Accordingly, many researchers exploited the physiological changes of the mucosal barrier for designing nanoparticulate drug delivery systems to target inflamed tissues. Others exploited biocompatibility and relative affordability of polysaccharides to test their intrinsic anti-inflammatory and healing properties in IBD models. This critical review updates state of the art on advances in IBD treatment. Data on using polysaccharide nanoparticulate drug delivery systems for IBD treatment are reviewed and discussed.

Neuroinflammation as an etiological trigger for depression comorbid with inflammatory bowel disease

Patients with inflammatory bowel disease (IBD) suffer from depression at higher rates than the general population. An etiological trigger of depressive symptoms is theorised to be inflammation within the central nervous system. It is believed that heightened intestinal inflammation and dysfunction of the enteric nervous system (ENS) contribute to impaired intestinal permeability, which facilitates the translocation of intestinal enterotoxins into the blood circulation. Consequently, these may compromise the immunological and physiological functioning of distant non-intestinal tissues such as the brain. In vivo models of colitis provide evidence of increased blood–brain barrier permeability and enhanced central nervous system (CNS) immune activity triggered by intestinal enterotoxins and blood-borne inflammatory mediators. Understanding the immunological, physiological, and structural changes associated with IBD and neuroinflammation may aid in the development of more tailored and suitable pharmaceutical treatment for IBD-associated depression.

Dietary Interventions Ameliorate Infectious Colitis by Restoring the Microbiome and Promoting Stem Cell Proliferation in Mice

Decreases in short-chain-fatty-acids (SCFAs) are linked to inflammatory bowel disease (IBD). Yet, the mechanisms through which SCFAs promote wound healing, orchestrated by intestinal stem cells, are poorly understood. We discovered that, in mice with Citrobacter rodentium (CR)-induced infectious colitis, treatment with Pectin and Tributyrin diets reduced the severity of colitis by restoring Firmicutes and Bacteroidetes and by increasing mucus production. RNA-seq in young adult mouse colon (YAMC) cells identified higher expression of Lgr4, Lgr6, DCLK1, Muc2, and SIGGIR after Butyrate treatment. Lineage tracing in CR-infected Lgr5-EGFP-IRES-CreERT2/ROSA26-LacZ (Lgr5-R) mice also revealed an expansion of LacZ-labeled Lgr5(+) stem cells in the colons of both Pectin and Tributyrin-treated mice compared to control. Interestingly, gut microbiota was required for Pectin but not Tributyrin-induced Lgr5(+) stem cell expansion. YAMC cells treated with sodium butyrate exhibited increased Lgr5 promoter reporter activity due to direct Butyrate binding with Lgr5 at -4.0 Kcal/mol, leading to thermal stabilization. Upon ChIP-seq, H3K4me3 increased near Lgr5 transcription start site that contained the consensus binding motif for a transcriptional activator of Lgr5 (SPIB). Thus, a multitude of effects on gut microbiome, differential gene expression, and/or expansion of Lgr5(+) stem cells seem to underlie amelioration of colitis following dietary intervention.

Exclusive inhibition of IL-6 trans-signaling by soluble gp130FlyRFc

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A variety of sgp130Fc muteins was generated.

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Introduction of a gp130 SNP (R281Q) into sgp130Fc increases IL-6 specificity.

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The sgp130Fc variant sgp130^FlyR exclusively affects IL-6 trans-signaling.

gp130 is the signal-transducing receptor for the Interleukin (IL)-6 type cytokines IL-6 and IL-11. To induce signaling, IL-6 forms a complex with IL-6 receptor (IL-6R) and IL-11 with IL-11 receptor (IL-11R). Membrane-bound IL-6R and IL-11R in complex with gp130 and the cytokine mediate classic-signaling, whereas trans-signaling needs soluble IL-6R and IL-11R variants. Interleukin (IL)-6 trans-signaling is of particular importance because it drives the development of autoimmune diseases, including rheumatoid arthritis and chronic inflammatory bowel diseases, whereas a role for IL-11 trans-signaling remains elusive. Soluble gp130 selectively inhibits trans-signaling of IL-6 whereas both, classic- and trans-signaling are abrogated by IL-6- and IL-6R-antibodies. Recently, we described an optimized sgp130 variant, which carries three amino acid substitutions T102Y/Q113F/N114L (sgp130^FlyFc) resulting in reduced inhibition of IL-11 trans-signaling by increasing the affinity of sgp130 for the site I of IL-6. Moreover, we described that the patient mutation R281Q in gp130 results in reduced IL-11 signaling. Here, we show that the combination of T102Y/Q113F/N114L and R281Q in the new variant sgp130^FlyRFc results in complete preservation of IL-11 mediated trans-signaling, whereas inhibition of IL-6 trans-signaling is maintained. Since sgp130Fc (olamkicept) has successfully completed a phase IIa trial in Crohn’s disease (CD) and ulcerative colitis, sgp130^FlyRFc might serve as second-generation therapeutic to diminish IL-11 trans-signaling cross-reactivity.

Class Ib MHC-Mediated Immune Interactions Play a Critical Role in Maintaining Mucosal Homeostasis in the Mammalian Large Intestine

Lymphocytes within the intestinal epithelial layer (IEL) in mammals have unique composition compared with their counterparts in the lamina propria. Little is known about the role of some of the key colonic IEL subsets, such as TCRαβ⁺CD8⁺ T cells, in inflammation. We have recently described liver-enriched innate-like TCRαβ⁺CD8αα regulatory T cells, partly controlled by the non-classical MHC molecule, Qa-1^b, that upon adoptive transfer protect from T cell-induced colitis. In this study, we found that TCRαβ⁺CD8αα T cells are reduced among the colonic IEL during inflammation, and that their activation with an agonistic peptide leads to significant Qa-1^b-dependent protection in an acute model of colitis. Cellular expression of Qa-1^b during inflammation and corresponding dependency in peptide-mediated protection suggest that Batf3-dependent CD103⁺CD11b^- type 1 conventional dendritic cells control the protective function of TCRαβ⁺CD8αα T cells in the colonic epithelium. In the colitis model, expression of the potential barrier-protective gene, Muc2, is enhanced upon administration of a Qa-1b agonistic peptide. Notably, in steady state, the mucin metabolizing Akkermansia muciniphila was found in significantly lower abundance amid a dramatic change in overall microbiome and metabolome, increased IL-6 in explant culture, and enhanced sensitivity to dextran sulfate sodium in Qa-1b deficiency. Finally, in patients with inflammatory bowel disease, we found upregulation of HLA-E, a Qa-1^b analog with inflammation and biologic non-response, in silico, suggesting the importance of this regulatory mechanism across species.

RKIP Pleiotropic Activities in Cancer and Inflammatory Diseases: Role in Immunity

Simple Summary

The human body consists of tissues and organs formed by cells. In each cell there is a switch that allows the cell to divide or not. In contrast, cancer cells have their switch on which allow them to divide and invade other sites leading to death. Over two decades ago, Doctor Kam Yeung, University of Toledo, Ohio, has identified a factor (RKIP) that is responsible for the on/off switch which functions normally in healthy tissues but is inactive or absent in cancers. Since this early discovery, many additional properties have been ascribed to RKIP including its role in inhibiting cancer metastasis and resistance to therapeutics and its role in modulating the normal immune response. This review describes all of the above functions of RKIP and suggesting therapeutics to induce RKIP in cancers to inhibit their growth and metastases as well as inhibit its activity to treat non-cancerous inflammatory diseases.

Abstract

Several gene products play pivotal roles in the induction of inflammation and the progression of cancer. The Raf kinase inhibitory protein (RKIP) is a cytosolic protein that exerts pleiotropic activities in such conditions, and thus regulates oncogenesis and immune-mediated diseases through its deregulation. Herein, we review the general properties of RKIP, including its: (i) molecular structure; (ii) involvement in various cell signaling pathways (i.e., inhibition of the Raf/MEK/ERK pathway; the NF-kB pathway; GRK-2 or the STAT-3 pathway; as well as regulation of the GSK3Beta signaling; and the spindle checkpoints); (iii) regulation of RKIP expression; (iv) expression’s effects on oncogenesis; (v) role in the regulation of the immune system to diseases (i.e., RKIP regulation of T cell functions; the secretion of cytokines and immune mediators, apoptosis, immune check point inhibitors and RKIP involvement in inflammatory diseases); and (vi) bioinformatic analysis between normal and malignant tissues, as well as across various immune-related cells. Overall, the regulation of RKIP in different cancers and inflammatory diseases suggest that it can be used as a potential therapeutic target in the treatment of these diseases.

Anti-Osteoporotic Effects of n-trans-Hibiscusamide and Its Derivative Alleviate Ovariectomy-Induced Bone Loss in Mice by Regulating RANKL-Induced Signaling

Osteoporosis is characterized by the deterioration of bone structures and decreased bone mass, leading to an increased risk of fracture. Estrogen deficiency in postmenopausal women and aging are major factors of osteoporosis and are some of the reasons for reduced quality of life. In this study, we investigated the effects of n-trans-hibiscusamide (NHA) and its derivative 4-O-(E)-feruloyl-N-(E)-hibiscusamide (HAD) on receptor activator of nuclear factor kappa-Β (NF-κB) ligand (RANKL)-induced osteoclast differentiation and an ovariectomized osteoporosis mouse model. NHA and HAD significantly inhibited the differentiation of osteoclasts from bone marrow-derived macrophages (BMMs) and the expression of osteoclast differentiation-related genes. At the molecular level, NHA and HAD significantly downregulated the phosphorylation of mitogen-activated protein kinase (MAPK) signaling molecules. However, Akt and NF-κB phosphorylation was inhibited only after NHA or HAD treatment. In the ovariectomy (OVX)-induced osteoporosis model, both NHA and HAD effectively improved trabecular bone structure. C-terminal telopeptide (CTX), a bone resorption marker, and RANKL, an osteoclast stimulation factor, were significantly reduced by NHA and HAD. The tartrate-resistant acid phosphatase (TRAP)-stained area, which indicates the osteoclast area, was also decreased by these compounds. These results show the potential of NHA and HAD as therapeutic agents for osteoporosis.

Regulation of meprin metalloproteases in mucosal homeostasis

Mucus is covering the entire epithelium of the gastrointestinal tract (GIT), building the interface for the symbiosis between microorganisms and their host. Hence, a disrupted mucosal barrier or alterations of proper mucus composition, including the gut microbiota, can cause severe infection and inflammation. Meprin metalloproteases are well-known to cleave various pro-inflammatory molecules, contributing to the onset and progression of pathological conditions including sepsis, pulmonary hypertension or inflammatory bowel disease (IBD). Moreover, meprins have an impact on migration and infiltration of immune cells like monocytes or leukocytes during intestinal inflammation by cleaving tight junction proteins or cell adhesion molecules, thereby disrupting epithelial cell barrier and promoting transendothelial cell migration. Interestingly, both meprin α and meprin β are susceptibility genes for IBD. However, both genes are significantly downregulated in inflamed intestinal tissue in contrast to healthy donors. Therefore, a detailed understanding of the underlying molecular mechanisms is the basis for developing new and effective therapies against manifold pathologies like IBD. This review focuses on the regulation of meprin metalloproteases and its impact on physiological and pathological conditions related to mucosal homeostasis.

The Role of β-Carotene in Colonic Inflammation and Intestinal Barrier Integrity

Background: Carotenoids are naturally occurring pigments accounting for the brilliant colors of fruits and vegetables. They may display antioxidant and anti-inflammatory properties in humans besides being precursors to vitamin A. There is a gap of knowledge in examining their role within colonic epithelial cells. We proposed to address this research gap by examining the effects of a major dietary carotenoid, β-carotene, in the in vitro epithelial cell model. Methods: We examined the function of β-carotene in the lipopolysaccharide (LPS)/toll-like receptor 4 (TLR4) signaling pathway. We conducted western blotting assays to evaluate expressions of TLR4 and its co-receptor, CD14. We also examined NF-κB p65 subunit protein levels in the model system. Furthermore, we studied the impact of β-carotene on the tight junction proteins, claudin-1, and occludin. We further carried out immunocytochemistry experiments to detect and visualize claudin-1 expression. Results: β-Carotene reduced LPS-induced intestinal inflammation in colonic epithelial cells. β-Carotene also promoted the levels of tight junction proteins, which might lead to enhanced barrier function. Conclusions: β-Carotene could play a role in modulating the LPS-induced TLR4 signaling pathway and in enhancing tight junction proteins. The findings will shed light on the role of β-carotene in colonic inflammation and also potentially in metabolic disorders since higher levels of LPS might induce features of metabolic diseases.

Utilization of physiologically-based pharmacokinetic model to assess disease-mediated therapeutic protein-disease-drug interaction in immune-mediated inflammatory diseases

It is known that interleukin-6 (IL-6) can significantly modulate some key drug-metabolizing enzymes, such as phase I cytochrome P450s (CYPs). In this study, a physiologically-based pharmacokinetic (PBPK) model was developed to assess CYPs mediated therapeutic protein drug interactions (TP-DIs) in patients with immune-mediated inflammatory diseases (IMIDs) with elevated systemic IL-6 levels when treated by anti-IL-6 therapies. Literature data of IL-6 levels in various diseases were incorporated in SimCYP to construct respective virtual patient populations. The modulation effects of systemic IL-6 level and local IL-6 level in the gastrointestinal tract (GI) on CYPs activities were assessed. Upon blockade of the IL-6 signaling pathway by an anti-IL-6 treatment, the area under plasma concentration versus time curves (AUCs) of S-warfarin, omeprazole, and midazolam were predicted to decrease by up to 40%, 42%, and 46%, respectively. In patients with Crohn's disease and ulcerative colitis treated with an anti-IL-6 therapy, the lowering of the elevated IL-6 levels in the local GI tissue were predicted to result in further decreases in AUCs of those CYP substrates. The propensity of TP-DIs under comorbidity conditions, such as in patients with cancer with IMID, were also explored. With further validation with relevant clinical data, this PBPK model may provide an in silico way to quantify the magnitude of potential TP-DI in patients with elevated IL-6 levels when an anti-IL-6 therapeutic is used with concomitant small-molecule drugs. This model may be further adapted to evaluate the CYP modulation effect by other therapeutic modalities, which would significantly alter levels of proinflammatory cytokines during the treatment period.

Depression in individuals who subsequently develop inflammatory bowel disease: a population-based nested case-control study

OBJECTIVE

Depression is a potential risk factor for developing IBD. This association may be related to GI symptoms occurring before diagnosis. We aimed to determine whether depression, adjusted for pre-existing GI symptoms, is associated with subsequent IBD.

DESIGN

We conducted a nested case-control study using the Clinical Practice Research Datalink identifying incident cases of UC and Crohn's disease (CD) from 1998 to 2016. Controls without IBD were matched for age and sex. We measured exposure to prevalent depression 4.5-5.5 years before IBD diagnosis. We created two sub-groups with prevalent depression based on whether individuals had reported GI symptoms before the onset of depression. We used conditional logistic regression to derive ORs for the risk of IBD depending on depression status.

RESULTS

We identified 10 829 UC cases, 4531 CD cases and 15 360 controls. There was an excess of prevalent depression 5 years before IBD diagnosis relative to controls (UC: 3.7% vs 2.7%, CD 3.7% vs 2.9%). Individuals with GI symptoms prior to the diagnosis of depression had increased adjusted risks of developing UC and CD compared with those without depression (UC: OR 1.47, 95% CI 1.21 to 1.79; CD: OR 1.41, 95% CI 1.04 to 1.92). Individuals with depression alone had similar risks of UC and CD to those without depression (UC: OR 1.13, 95% CI 0.99 to 1.29; CD: OR 1.12, 95% CI 0.91 to 1.38).

CONCLUSIONS

Depression, in the absence of prior GI symptoms, is not associated with subsequent development of IBD. However, depression with GI symptoms should prompt investigation for IBD.

Unravelling the broader complexity of IL-6 involvement in health and disease

The classification of interleukin-6 (IL-6) as a pro-inflammatory cytokine undervalues the biological impact of this cytokine in health and disease. With broad activities affecting the immune system, tissue homeostasis and metabolic processes, IL-6 displays complex biology. The significance of these involvements has become increasingly important in clinical settings where IL-6 is identified as a prominent target for therapy. Here, clinical experience with IL-6 antagonists emphasises the need to understand the context-dependent properties of IL-6 within an inflammatory environment and the anticipated or unexpected consequences of IL-6 blockade. In this review, we will describe the immunobiology of IL-6 and explore the gamut of IL-6 bioactivity affecting the clinical response to biological drugs targeting this cytokine pathway.

Selective inhibition of IL-6 trans-signaling by a miniaturized, optimized chimeric soluble gp130 inhibits TH17 cell expansion

The cytokine interleukin-6 (IL-6) signals through three mechanisms called classic signaling, trans-signaling, and trans-presentation. IL-6 trans-signaling is distinctly mediated through a soluble form of its transmembrane receptor IL-6R (sIL-6R) and the coreceptor gp130 and is implicated in multiple autoimmune diseases. Although a soluble form of gp130 (sgp130) inhibits only IL-6 trans-signaling, it also blocks an analogous trans-signaling mechanism of IL-11 and its soluble receptor sIL-11R. Here, we report miniaturized chimeric soluble gp130 variants that efficiently trap IL-6:sIL-6R but not IL-11:sIL-11R complexes. We designed a novel IL-6 trans-signaling trap by fusing a miniaturized sgp130 variant to an IL-6:sIL-6R complex-binding nanobody and the Fc portion of immunoglobulin G (IgG). This trap, called cs-130Fc, exhibited improved inhibition of as well as increased selectivity for IL-6 trans-signaling compared to the conventional fusion protein sgp130Fc. We introduced affinity-enhancing mutations in cs-130Fc and sgp130Fc that further improved selectivity toward IL-6 trans-signaling. Moreover, cs-130Fc efficiently inhibited the expansion of T helper 17 (TH17) cells in cultures of mouse CD4+ T cells treated with IL-6:sIL-6R. Thus, these variants may provide or lead to the development of more precisely targeted therapeutics for inflammatory disorders associated with IL-6 trans-signaling.

Flaxseed oligosaccharides alleviate DSS-induced colitis through modulation of gut microbiota and repair of the intestinal barrier in mice

Intestinal epithelial barrier dysfunction with dysbiosis of gut microbiota contributes to the occurrence and acceleration of colitis. This study aimed to evaluate the effect of flaxseed oligosaccharides (FOSs) on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) mice and to elucidate the underlying mechanisms. UC was induced in mice by administering 2% DSS in drinking water for 8 days. Then, FOS (50 mg kg-1 d-1, 100 mg kg-1 d-1 and 200 mg kg-1 d-1) was administered by gavage for 14 days. The results showed that FOS treatment (200 mg kg-1 d-1) significantly ameliorated colitis by decreasing disease activity index (DAI), increasing colon length and improving colonic histology. FOS treatment (200 mg kg-1 d-1) down-regulated the critical markers of oxidative stresses, including malondialdehyde (MDA) and myeloperoxidase (MPO). Furthermore, FOS (200 mg kg-1 d-1) significantly suppressed the levels of pro-inflammatory cytokines including tumor necrosis factor (TNF)-α, interleukin (IL)-6 and interleukin (IL)-1β but increased that of anti-inflammatory cytokine interleukin (IL)-10. The 16S rDNA gene high-throughput sequencing results indicated that FOS treatment increased the gut microbial diversity and inhibited the proliferation of inflammation-related bacteria such as unidentified_Clostridiales. An increase in total short-chain fatty acids (SCFAs), propionic acid and butyric acid, was also observed by FOS supplementation. FOS (200 mg kg-1d-1) also protected the intestinal barrier by increasing the protein levels of Claudin1 and Occludin. In conclusion, FOS attenuated DSS-induced colitis by modulating the gut microbiota and repairing the intestinal barrier.

The association between diarrhea and serum cytokines in patients with gynecologic cancer treated with surgery and pelvic chemoradiotherapy

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Gastrointestinal symptoms including diarrhea and constipation are common in patients with gynecologic cancer receiving pelvic chemoradiotherapy.

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There was an increase of serum IL-6 levels in patients with ≥grade 2 diarrhea during pelvic chemoradiotherapy.

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Serum IL-1β and TNFα levels did not change during pelvic chemoradiotherapy.

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Radiotherapy-related and clinical factors affect the development of chemoradiotherapy-induced diarrhea.

Purpose

We investigated whether serum cytokines including Interleukin (IL)-1β, IL-6 and tumor necrosis factor alpha (TNFα) are increased during pelvic chemoradiotherapy (CRT) in patients with gynecologic malignancies, and sought to identify prognostic factors for the development of diarrhea during pelvic CRT.

Materials and methods

Patients with cervical or endometrial cancer receiving postoperative pelvic CRT were eligible for this prospective study. Patients were evaluated weekly during CRT for symptoms, including diarrhea and constipation. Serum cytokine levels were measured using immunoassays 1 week before CRT, and at week 3 and 5–6 during CRT. Radiotherapy-related parameters such as mean dose, minimum dose, and maximum dose to the small bowel were also analyzed. Multivariate logistic regression analysis was used to assess factors associated with development of enteritis symptoms.

Results

Twenty-six patients were enrolled, all of whom were eligible for symptom and dosimetric parameter evaluation; 24 were eligible for cytokine level measurement. Cytokine levels did not differ between patients with and without diarrhea before CRT. IL-6 levels increased during CRT, and were significantly higher in patients with diarrhea ≥grade 2 than in those with grade 0–1 at week 5–6 (6.771 ± 2.657 pg/mL vs. 3.396 ± 0.499 pg/mL, p = 0.046). Serum IL-1β and TNFα levels did not change during CRT. Diarrhea before CRT and the maximum dose to the small bowel were independent prognostic factors for CRT-induced diarrhea in the multivariate analysis.

Conclusions

There was an increase of serum IL-6 levels in patients with ≥grade 2 diarrhea during pelvic CRT. Serum IL-1β and TNFα levels did not change during CRT. Radiotherapy-related and clinical factors affect the development of diarrhea during pelvic CRT.

Local Immune Changes in Early Stages of Inflammation and Carcinogenesis Correlate with the Collagen Scaffold Changes of the Colon Mucosa

Simple Summary

Chronic colitis and colon cancer develop for alteration of the mucosa homeostatic regulation, also involving TGF-β1. Dextran sulphate sodium (DSS)-induced colitis and azoxymethane (AOM)-induced colorectal carcinogenesis animal models allow for the investigation of the pathological evolution steps. Since chronic inflammation is a common factor, we aimed to explore in rat models the colon mucosa immunological and structural conditions at one month after the end of the inductions, a transition period between acute effects and established lesions. We found, in comparison to healthy controls, downregulation of inflammatory cytokines (except IL-6) and of TGF-β1. At the same time, the collagen scaffold was significantly remodelled in both groups. We conclude that the pro-inflammatory cytokines, in front of a downregulated TGF-β1, sustained a smouldering inflammation with structural changes preparing the niche of both pathologies (ulcerative colitis with fibrosis; tumour). The collagen scaffold changes pointing to an unnoticed inflammation may be suggested as a possible pre-neoplastic condition marker.

Abstract

Continuous activation of the immune system inside a tissue can lead to remodelling of the tissue structure and creation of a specific microenvironment, such as during the tumour development. Chronic inflammation is a central player in stimulating changes that alter the tissue stroma and can lead to fibrotic evolution. In the colon mucosa, regulatory mechanisms, including TGF-β1, avoid damaging inflammation in front of the continuous challenge by the intestinal microbiome. Inducing either DSS colitis or AOM colorectal carcinogenesis in AVN-Wistar rats, we evaluated at one month after the end of each treatment whether immunological changes and remodelling of the collagen scaffold were already in development. At this time point, we found in both models a general downregulation of pro-inflammatory cytokines and even of TGF-β1, but not of IL-6. Moreover, we demonstrated by multi-photon microscopy the simultaneously presence of pro-fibrotic remodelling of the collagen scaffold, with measurable changes in comparison to the control mucosa. The scaffold was significantly modified depending on the type of induced stimulation. These results suggest that at one month after the end of the DSS or AOM inductions, a smouldering inflammation is present in both induced conditions, since the pro-inflammatory cytokines still exceed, in proportion, the local homeostatic regulation of which TGF-β1 is a part (inflammatory threshold). Such an inflammation appears sufficient to sustain remodelling of the collagen scaffold that may be taken as a possible pathological marker for revealing pre-neoplastic inflammation.

A Potential Role of IL-6/IL-6R in the Development and Management of Colon Cancer

Colorectal cancer (CRC) is the third most frequent cancer worldwide and the second greatest cause of cancer deaths. About 75% of all CRCs are sporadic cancers and arise following somatic mutations, while about 10% are hereditary cancers caused by germline mutations in specific genes. Several factors, such as growth factors, cytokines, and genetic or epigenetic alterations in specific oncogenes or tumor-suppressor genes, play a role during the adenoma-carcinoma sequence. Recent studies have reported an increase in interleukin-6 (IL-6) and soluble interleukin-6 receptor (sIL-6R) levels in the sera of patients affected by colon cancer that correlate with the tumor size, suggesting a potential role for IL-6 in colon cancer progression. IL-6 is a pleiotropic cytokine showing both pro- and anti-inflammatory roles. Two different types of IL-6 signaling are known. Classic IL-6 signaling involves the binding of IL-6 to its membrane receptor on the surfaces of target cells; alternatively, IL-6 binds to sIL-6R in a process called IL-6 trans-signaling. The activation of IL-6 trans-signaling by metalloproteinases has been described during colon cancer progression and metastasis, involving a shift from membrane-bound interleukin-6 receptor (IL-6R) expression on the tumor cell surface toward the release of soluble IL-6R. In this review, we aim to shed light on the role of IL-6 signaling pathway alterations in sporadic colorectal cancer and the development of familial polyposis syndrome. Furthermore, we evaluate the possible roles of IL-6 and IL-6R as biomarkers useful in disease follow-up and as potential targets for therapy, such as monoclonal antibodies against IL-6 or IL-6R, or a food-based approach against IL-6.

The Role of microRNAs in Development of Colitis-Associated Colorectal Cancer

Colorectal cancer (CRC) is the third most deadly cancer worldwide, and inflammatory bowel disease (IBD) is one of the critical factors in CRC carcinogenesis. IBD is responsible for an unphysiological and sustained chronic inflammation environment favoring the transformation. MicroRNAs (miRNAs) belong to a class of highly conserved short single-stranded segments (18-25 nucleotides) non-coding RNA and have been extensively discussed in both CRC and IBD. However, the role of miRNAs in the development of colitis-associated CRC (CAC) is less clear. The aim of this review is to summarize the major upregulated (miR-18a, miR-19a, miR-21, miR-31, miR-155 and miR-214) and downregulated (miR-124, miR-193a-3p and miR-139-5p) miRNAs in CAC, and their roles in genes' expression modulation in chronic colonic-inflammation-induced carcinogenesis, including programmed cell-death pathways. These miRNAs dysregulation could be applied for early CAC diagnosis, to predict therapy efficacy and for precision treatment.

Association of atrial fibrillation with outcomes in patients hospitalized with inflammatory bowel disease: an analysis of the National Inpatient Sample

Introduction

We aimed to determine in-hospital outcomes, length of hospital stay (LOS) and resource utilization in a contemporary cohort of patients with inflammatory bowel disease (IBD) and atrial fibrillation (AFIB).

Material and methods

The National Inpatient Sample database October 2015 to December 2017 was utilized for data analysis using the International Classification of Diseases, Tenth Revision codes to identify the patients with the principal diagnosis of IBD.

Results

Of 714,863 IBD patients, 64,599 had a diagnosis of both IBD and AFIB. We found that IBD patients with AFIB had a greater incidence of in-hospital mortality (OR = 1.3; 95% CI: 1.1–1.4), sepsis (OR = 1.2; 95% CI: 1.1–1.3), mechanical ventilation (OR = 1.2; 95% CI: 1.1–1.5), shock requiring vasopressor (OR = 1.4; 95% CI: 1.1–1.9), lower gastrointestinal bleeding (LGIB) (OR = 1.09, 95% CI: 1.04–1.1), and hemorrhage requiring blood transfusion (OR = 1.2, 95% CI: 1.17–1.37). Mean LOS ± SD, mean total charges and total costs were higher in patients with IBD and AFIB.

Conclusions

In this study, IBD with AFIB was associated with increased in-hospital mortality and morbidity, mean LOS and resource utilization.

Canthin-6-one ameliorates TNBS-induced colitis in rats by modulating inflammation and oxidative stress. An in vivo and in silico approach

Canthin-6-one (Cant) is an indole alkaloid found in several botanical drugs used as medicines, reported to be gastroprotective, anti-inflammatory, anti-microbial, anti-diarrheal and anti-proliferative. We aimed to explore Cant in the management of colitis using a trinitrobenzenesulfonic acid (TNBS)-induced rat model. Cant (1, 5 and 25 mg/kg) was administered by oral gavage to Wistar rats followed by induction of colitis with TNBS. Macroscopic and histopathological scores, myeloperoxidase (MPO), malondialdehyde (MDA) and reduced glutathione (GSH) were assessed in colon tissues. Pro- (TNF-α, IL-1β and IL-12p70) and anti-inflammatory (IL-10) cytokines, and vascular endothelial growth factor (VEGF) were also quantified. Mitogen-activated protein kinase 14 (MAPK14) and Toll-like receptor-8 (TLR8), as putative targets, were considered through in silico analysis. Cant (5 and 25 mg/kg) reduced macroscopic and histological colon damage scores in TNBS-treated rats. MPO and MDA were reduced by up to 61.69% and 92.45%, respectively, compared to TNBS-treated rats alone. Glutathione concentration was reduced in rats administered with TNBS alone (50.00% of sham group) but restored to 72.73% (of sham group) with Cant treatment. TNF-α, IL-1β, IL-12p70 and VEGF were reduced, and anti-inflammatory IL-10 was increased following Cant administration compared to rats administered TNBS alone. Docking ligation results for MAPK14 (p38α) and TLR8 with Cant, confirmed that these proteins are feasible putative targets. Cant has an anti-inflammatory effect in the intestine by down-regulating molecular immune mediators and decreasing oxidative stress. Therefore, Cant could have therapeutic potential for the treatment of inflammatory bowel disease and related syndromes.

The impact of visceral obesity on chronic constipation, inflammation, immune function and cognitive function in patients with inflammatory bowel disease

Objective: Obesity has gained attention among patients with inflammatory bowel disease (IBD). The impact of visceral obesity on chronic constipation, inflammation, immune function and cognition after diagnosis of IBD is still unknown.

Methods: This is a cross-sectional study of 150 IBD patients. Patients’ visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) were measured and were grouped according to visceral obesity. The potential impact of visceral obesity on cognitive function were evaluated using Mini-Mental State Examination. We evaluated patients’ incidence of chronic constipation, levels of interleukin-6 (IL-6), T cells and body mass index in two groups.

Results: The prevalence of visceral obesity was 51% (37 out of 72) for Crohn’s disease (CD) patients and 26% for UC patients (20 out of 78 patients). CD patients with visceral obesity has higher incidence of chronic constipation (81% vs. 57%, P = 0.028), higher IL-6 levels (15.28 pg/ml vs. 9.429 pg/ml, P = 0.007) and lower CD4⁺ T cells (32.7% vs. 44.0%, P < 0.001). VAT/SAT ratio is associated with BMI (P < 0.001).

Conclusions: IBD patients had high risks of visceral obesity. CD Patients with visceral obesity had higher prevalence of chronic constipation, higher inflammation levels, decreased immune function.

IL6 genetic variants haplotype is associated with susceptibility and disease activity but not with therapy response in patients with inflammatory bowel disease

PURPOSE

The aim of the present study was to evaluate the IL6 -174 G>C (rs1800795) and -572 G>C (rs1800796) genetic variants and their association with inflammatory bowel diseases (IBDs), disease activity, and response to TNF-α inhibitors.

METHODS

The study included 178 patients with IBD and 224 healthy controls. Among the IBD patients, 66 of them were in use of TNF-α inhibitors therapy and were followed during 48 weeks and categorized as responders and non-responders.

RESULTS

In total, 89 (50.0%) had ulcerative colitis (UC) and 89 (50.0%) had Crohn's disease (CD). The IL6 -572 CC genotype presented a protective effect in CD patients in codominant and recessive models, while the IL6 -174 CC genotype was associated with susceptibility to UC and CD. The presence of G/C haplotype in the recessive model (GCGC) was associated with UC. The Crohn's disease endoscopic index of severity was low in those patients carrying the GCGC haplotype. It was observed that there was no association between the IL6 genetic variants and TNF-α inhibitor therapy response.

CONCLUSION

The G/C haplotype (recessive model) was associated with susceptibility to UC but not to CD. However, the G/C haplotype (dominant model) was associated with the endoscopic activity of CD. Moreover, these IL6 variants did not predict the TNF-α inhibitor therapy response.

Knockout-Induced Pluripotent Stem Cells for Disease and Therapy Modeling of IL-10-Associated Primary Immunodeficiencies

Samples from patients with rare diseases, such as primary immunodeficiencies, are often limited, which hampers careful analysis of the pathomechanisms involved in immune cell dysregulation. To overcome this issue, induced pluripotent stem cells (iPSCs) represent an almost inexhaustible cell source and thus provide an excellent opportunity to generate disease models for rare diseases and to validate new therapeutic approaches. To obtain a better understanding of primary immunodeficiencies associated with the interleukin (IL)-10 signaling pathway, for example, very-early-onset inflammatory bowel disease (VEO-IBD), we generated genetic knockouts (KOs) of IL-10RA (IL-10 receptor α-chain) and IL-10RB (IL-10 receptor β-chain) as well as the downstream targets of the IL-10-receptor (IL-10R) signal transducers and activators of transcription (STAT)1 and STAT3 via an sgRNA (single-guide RNA)-CRISPR-Cas9-expressing lentiviral system. IL-10 signaling-associated KO models and a VEO-IBD patient-derived iPSC clone were differentiated into macrophages for disease models. IL-10R- or STAT3-deficient disease models showed no IL-10-induced BCL3 or SOCS3 expression, whereas lipopolysaccharide (LPS) stimulation induced IL-10R independently of BCL3 and SOCS3 expression. Cytokine secretion profiles from iPSC-derived macrophage disease models showed that IL-10 was involved in many inflammatory cytokine secretions, which indicated formation of both anti- and proinflammatory macrophage phenotypes. Macrophage-secreted cytokines were separated into IL-10R- and STAT3-dependent (IL-6, TNF-α), or into IL-10R-, STAT1-, and STAT3-dependent cytokines (CCL2, CXCL10). Importantly, lentiviral correction restored IL-10-mediated regulation of LPS-induced cytokine secretion in corrected IL-10RB, STAT1, and VEO-IBD patient-derived disease models. Furthermore, treatment of IL-10RB-deficient macrophages with anti-inflammatory small molecules (SB202190, filgotinib) reduced proinflammatory cytokine secretion patterns. Taken together, the described iPSC KO models gave new insights into the pathomechanisms of immune cell dysregulation and served as model systems to test potential therapeutic approaches, including lentiviral gene therapy and targeted small-molecule treatment.

Biological characteristics of IL-6 and related intestinal diseases

The intestine serves as an important digestive and the largest immune organ in the body. Interleukin-6(IL-6), an important mediator of various pathways, participates in the interactions between different kinds of cells and closely correlates with intestinal physiological and pathological condition. In this review we summarize the signaling pathways of IL-6 and its functions in maintaining intestinal homeostasis. We also explored its relation with nervous system and highlight its potential role in Parkinson's disease. Based on its specialty of the double-side influences on intestinal tumors and inflammation, we summarize how they are done through distinctive process.

Effect of resistance exercise training on Crohn's disease patients

Crohn’s disease (CD) is observed with increased levels of cytokines which cause inflammation in many parts of the digestive tract. Aerobic exercise contributes to the reduction of the intestine’s inflammation and increases the quality of life. Another type of exercise that shows research interest about its effects on CD symptoms is the resistance exercise (RE). The aim of the study was to review the influence of RE on CD patients. The study’s literature was collected from PubMed and Scholar databases. According to the results, the main phase of a RE training program must have a gradual increase of intensity (60%–80%) and resting periods of 15–30 seconds after each exercise, and 2–3 minutes between exercises. Also, CD patients who were in remission improved the muscle strength and quality of life via their participation in RE training program. However, the secretion of interleukin-6 in both CD and RE contributes in various physiological mechanisms setting a contradictory role in the effectiveness of RE at the disease’s inflammatory situation. So, the use of RE training in CD patients needs more research for safer participation.

A systematic review of preclinical studies on the efficacy of propolis for the treatment of inflammatory bowel disease

Propolis is a resinous substance produced by bees from plants. There has been some evidence indicating that propolis may be a candidate for the treatment of inflammatory bowel disease (IBD) because of its potent antioxidant properties and ability to modulate immune response and gut microbiome. The objective of this systematic review was to investigate the role of propolis in the treatment of IBD, emphasizing possible mechanisms underlying the anti-inflammatory properties of it. Searches were performed in ISI, PubMed/Medline, Scopus, EMBASE, and Cochrane Library databases up to March 2020. According to the studies examined in this review, the administration of propolis can be useful in attenuating many aspects of clinical, macroscopic, and histological features of colitis in animal models. The efficacy of propolis in the treatment of IBD might be attributed to its potent antioxidants and anti-inflammatory activities. Propolis may also be involved in the modulation of the gut microbiota and in the improvement of the intestinal mucosal barrier function. The major mechanism of action is most likely to be mediated via the prevention of some transcriptional factors and associated proteins. However, future studies are warranted to investigate the clinical utility of propolis as a candidate in the treatment of IBD.

The impact of the level and distribution of methyl-esters of pectins on TLR2-1 dependent anti-inflammatory responses

Pectins have anti-inflammatory effects via Toll-like receptor (TLR) inhibition in a degree of methyl-esterification-(DM)-dependent manner. However, pectins also vary in distribution of methyl-esters over the galacturonic-acid (GalA) backbone (Degree of Blockiness - DB) and impact of this on anti-inflammatory capacity is unknown. Pectins mainly inhibit TLR2-1 but magnitude depends on both DM and DB. Low DM pectins (DM18/19) with both low (DB86) and high DB (DB94) strongly inhibit TLR2-1. However, pectins with intermediate DM (DM43/DM49) and high DB (DB60), but not with low DB (DB33), inhibit TLR2-1 as strongly as low DM. High DM pectins (DM84/88) with DB71 and DB91 do not inhibit TLR2-1 strongly. Pectin-binding to TLR2 was confirmed by capture-ELISA. In human macrophages, low DM and intermediate DM pectins with high DB inhibited TLR2-1 induced IL-6 secretion. Both high number and blockwise distribution of non-esterified GalA in pectins are responsible for the anti-inflammatory effects via inhibition of TLR2-1.

Dysregulation of IL6/IL6R-STAT3-SOCS3 signaling pathway in IBD-associated colorectal dysplastic lesions as compared to sporadic colorectal adenomas in non-IBD patients

BACKGROUND

IL6-IL6R-STAT3-SOCS3 signaling pathway is known to play important roles in regulating intestinal epithelial homeostasis, in pathogenesis of inflammatory bowel disease (IBD), and in tumorigenesis of colorectal neoplasia. We studied the expressions of these factors in IBD-associated dysplasia and compared to sporadic colorectal adenomas in non-IBD individuals.

MATERIALS AND METHODS

The expression of IL6, IL6R, STAT3, and SOCS3 within dysplastic as well as background non-dysplastic epithelial cells was evaluated by immunohistochemistry in 26 sporadic colorectal adenomas in non-IBD patients, 32 adenoma-like and 30 non-adenoma-like dysplastic lesions in IBD (41 ulcerative colitis, 21 Crohn's disease) patients. The level of expression of each factor was arbitrarily scored as 0, 1, 2, and 3.

RESULTS

In both IBD and non-IBD lesions, neoplastic epithelium showed a higher expression of all factors, except the IL6R, as compared to non-neoplastic epithelium. For non-neoplastic epithelium between IBD and non-IBD settings, the colitic epithelium showed a similar IL6, lower IL6R, higher STAT3, and higher SOCS3 expression. As compared to non-IBD adenomas, IBD-associated dysplasia showed a significantly lower IL6, lower IL6R, higher STAT3, and lower SOCS3 expression. Most notably, a parallel-elevation pattern of STAT3/SOCS3 expressions was seen in non-IBD adenomas but an inverse-expression pattern of STAT3/SOCS3 seen in IBD dysplastic lesions. No significant differences existed between adenoma-like and non-adenoma-like lesions.

CONCLUSIONS

IL6/IL6R-STAT3-SOCS3 signaling pathway does not seem to be preferentially associated with IBD-associated dysplasia. However, the STAT3-SOCS3 interaction appears dysregulated in IBD, characterized by a loss of STAT3/SOCS3 balance,i.e., loss of the normal negative regulation of SOCS3.

Novel Dietary Proteins Selectively Affect Intestinal Health In Vitro after Clostridium difficile-Secreted Toxin A Exposure

Bacterial gastroenteritis forms a burden on a global scale, both socially and economically. The Gram-positive bacterium Clostridium difficile is an inducer of gastrointestinal bacterial infections, often triggered following disruption of the microbiota by broad-spectrum antibiotics to treat other conditions. The clinical manifestatiaons, e.g., diarrhea, are driven by its toxins secretion, toxin A (TcdA) and toxin B (TcdB). Current therapies are focused on discontinuing patient medication, including antibiotics. However, relapse rates upon therapy are high (20-25%). Here, eighteen dietary proteins were evaluated for their capacity to restore gut health upon C. difficile-derived TcdA exposure. We used bioengineered intestinal tubules to assess proteins for their beneficial effects by examining the epithelial barrier, cell viability, brush-border enzyme activity, IL-6 secretion, IL-8 secretion and nitric oxide (NO) levels upon TcdA challenge. TcdA effectively disrupted the epithelial barrier, increased mitochondrial activity, but did not affect alkaline phosphatase activity, IL-6, IL-8 and NO levels. Intervention with dietary proteins did not show a protective effect on epithelial barrier integrity or mitochondrial activity. However, bovine plasma and potato protein increased alkaline phosphatase activity, egg-white protein increased IL-6 and IL-8 release and wheat, lesser mealworm and yeast protein increased NO levels after TcdA exposure. Hence, dietary proteins can influence parameters involved in intestinal physiology and immune activation suggesting that supplementation with specific dietary proteins may be of benefit during C. difficile infections.

Chemical Profile, Antioxidant, Anti-Inflammatory, and Anti-Cancer Effects of Italian Salvia rosmarinus Spenn. Methanol Leaves Extracts

In this study, we evaluated and compared the chemical composition, the antioxidant, anti-inflammatory, and anti-proliferative effects of four methanol extracts (R1–R4), of Salvia rosmarinus Spenn. in two different sites of Southern Italy obtained by maceration or ultrasound-assisted extraction. Extracts of S. rosmarinus collected on the Ionian coast are indicated with the abbreviations R1 (maceration) and R2 (ultrasound-assisted extraction). Extracts of S. rosmarinus collected on the Tyrrhenian coast are indicated with the abbreviations R3 (maceration) and R4 (ultrasound-assisted extraction). The chemical composition was analyzed using High Pressure liquid chromatography–Diod-Array detection–Electrospray ionization–Quadrupole–Mass Spectroscopy (HPLC-DAD-ESI-Q-MS). The antioxidant activity was analyzed by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) 2,2-diphenyl-1-picrylhydrazyl (DPPH), β-carotene bleaching, and Ferric Reducing Antioxidant Power (FRAP) assays. Antioxidant features were also assessed in lipopolysaccharide (LPS)-stimulated RAW-264.7 murine macrophages, evaluating Reactive Oxygen Species (ROS) production; in the same experimental model, the anti-inflammatory activity of the extracts was investigated. Interestingly, all extracts displayed antioxidant and anti-inflammatory properties. They exhibited significative nitrite production inhibitory activity, whith IC₅₀ values ranging from 3.46 to 5.53 µg/mL, without impairing cell viability. The anti-inflammatory activity was also investigated by Western Blotting and immunofluorescence assay, highlighting the R3 and R4 extracts ability to reduce NF-κB translocation, as well as to disrupt the MAPKs signaling pathway. Extracts exhibited both potential anti-proliferative activity on breast cancer cells, inducing apoptosis, without affecting non-tumorigenic cells, and the ability to inhibit MDA-MB-231 cells’ motility. Finally, the rosemary extracts treatment significantly reduced the power of conditioned media, from MCF-7 or MDA-MB-231 cells to induce nitrite production on RAW 264.7 cells, confirming their promising anti-inflammatory activity.

Resveratrol and Resveratrol-Aspirin Hybrid Compounds as Potent Intestinal Anti-Inflammatory and Anti-Tumor Drugs

Resveratrol (3,4,5-Trihydroxy-trans-stilbene) is a naturally occurring polyphenol that exhibits beneficial pleiotropic health effects. It is one of the most promising natural molecules in the prevention and treatment of chronic diseases and autoimmune disorders. One of the key limitations in the clinical use of resveratrol is its extensive metabolic processing to its glucuronides and sulfates. It has been estimated that around 75% of this polyphenol is excreted via feces and urine. To possibly alleviate the extensive metabolic processing and improve bioavailability, we have added segments of acetylsalicylic acid to resveratrol in an attempt to maintain the functional properties of both. We initially characterized resveratrol-aspirin derivatives as products that can inhibit cytochrome P450 Family 1 Subfamily A Member 1 (CYP1A1) activity, DNA methyltransferase (DNMT) activity, and cyclooxygenase (COX) activity. In this study, we provide a detailed analysis of how resveratrol and its aspirin derivatives can inhibit nuclear factor kappa B (NFκB) activation, cytokine production, the growth rate of cancer cells, and in vivo alleviate intestinal inflammation and tumor growth. We identified resveratrol derivatives C3 and C11 as closely preserving resveratrol bioactivities of growth inhibition of cancer cells, inhibition of NFκB activation, activation of sirtuin, and 5’ adenosine monophosphate-activated protein kinase (AMPK) activity. We speculate that the aspirin derivatives of resveratrol would be more metabolically stable, resulting in increased efficacy for treating immune disorders and as an anti-cancer agent.

Hemokinin-1 and substance P stimulate production of inflammatory cytokines and chemokines in human colonic mucosa via both NK1 and NK2 tachykinin receptors

There is increasing focus on the involvement of tachykinins in immune and inflammatory responses. Hemokinin-1 (HK-1) is a recently identified tachykinin that originates primarily from immune cells, and has structural similarities to substance P (SP), found mainly in neurons. However, there are species differences in HK-1, and the role of HK-1 in humans, particularly the intestine, has received minimal attention. The aim of this study was to investigate the inflammatory role of human HK-1 in the human colon. The effects of HK-1 and SP were compared on the production of multiple inflammatory cytokines and chemokines from human colonic mucosal explants. Data generated by Procarta multiplex assay and QuantiGene assay demonstrated that 4 h incubation with HK-1 (0.1 μM) significantly stimulated transcript expression and release of MCP-1, MIP-1α and β, RANTES, TNF-α, IL-1β and IL-6 from the mucosa. SP (0.1 μM) had comparable actions, but had no effect on MCP-1 or RANTES. These effects were inhibited separately by tachykinin NK₁ and NK₂ receptor antagonists SR140333 and SR48968 (both 0.1 μM), suggesting that these responses were mediated by both NK1 and NK2 receptors. In conclusion, these data support a novel inflammatory role for HK-1 in human colon, signaling via NK1 and NK2 receptors (and possibly other tachykinin-preferring receptors) to regulate the release of a broad spectrum of proinflammatory mediators. The study suggests that along with SP, HK-1 is also a proinflammatory mediator, likely involved in colonic inflammation, including inflammatory bowel disease (IBD).

Gut instincts: vitamin D/vitamin D receptor and microbiome in neurodevelopment disorders

The gut microbiome regulates a relationship with the brain known as the gut–microbiota–brain (GMB) axis. This interaction is influenced by immune cells, microbial metabolites and neurotransmitters. Recent findings show gut dysbiosis is prevalent in autism spectrum disorder (ASD) as well as attention deficit hyperactivity disorder (ADHD). There are previously established negative correlations among vitamin D, vitamin D receptor (VDR) levels and severity of ASD as well as ADHD. Both vitamin D and VDR are known to regulate homeostasis in the brain and the intestinal microbiome. This review summarizes the growing relationship between vitamin D/VDR signalling and the GMB axis in ASD and ADHD. We focus on current publications and summarize the progress of GMB in neurodevelopmental disorders, describe effects and mechanisms of vitamin D/VDR in regulating the microbiome and synoptically highlight the potential applications of targeting vitamin D/VDR signalling in neurodevelopment disorders.

Lessons on the Sigma-1 Receptor in TNBS-Induced Rat Colitis: Modulation of the UCHL-1, IL-6 Pathway

Inflammatory Bowel Disease (IBD) is an autoimmune ailment of the gastrointestinal (GI) tract, which is characterized by enhanced activation of proinflammatory cytokines. It is suggested that the sigma-1 receptor (σ1R) confers anti-inflammatory effects. As the exact pathogenesis of IBD is still unknown and treatment options are limited, we aimed to investigate the effects of σ1R in 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced experimental colitis. To this end, male Wistar-Harlan rats were used to model colitic inflammation through the administration of TNBS. To investigate the effects of σ1R, Fluvoxamine (FLV, σ1R agonist) and BD1063 (σ1R antagonist) were applied via intracolonic administration to the animals once a day for three days. Our radioligand binding studies indicated the existence of σ1Rs as [3H](+)-pentazocine binding sites, and FLV treatment increased the reduced σ1R maximum binding capacity in TNBS-induced colitis. Furthermore, FLV significantly attenuated the colonic damage, the effect of which was abolished by the administration of BD1063. Additionally, FLV potentially increased the expression of ubiquitin C-terminal hydrolase ligase-1 (UCHL-1) and the levels of endothelial nitric oxide synthase (eNOS), and decreased the levels of interleukin-6 (IL-6) and inducible NOS (iNOS) expression. In summary, our study offers evidence for the anti-inflammatory potential of FLV and σ1R in experimental colitis, and our results present a promising approach to the development of new σ1R-targeted treatment options against IBD.

Targeting IL-10, ZO-1 gene expression and IL-6/STAT-3 trans-signaling by a combination of atorvastatin and mesalazine to enhance anti-inflammatory effects and attenuates progression of oxazolone-induced colitis

Ulcerative colitis (UC) is a chronic inflammatory disease characterized by diffused inflammation of the colon and rectum mucosa. The pathogenesis of UC is multifactorial, and the exact underlying mechanisms remain poorly understood. This study aims to investigate the effect of mesalazine and atorvastatin combination in enhancing anti-inflammatory effects and attenuates progression of oxazolone colitis in rats. In the present study, male albino rats (N = 60) were divided into six groups (10 rats each), the first two groups served as normal control and a control saline group. Colitis was induced by intra-rectal administration of oxazolone in the 5th and 7th days after pre-sensitization. Then, rats were divided into untreated group, groups treated with mesalazine or atorvastatin or their combination. Colitis was assessed by colon length, body weight, and incidence of diarrhea, rectal bleeding, and histopathology of colon tissue. Colon tissues were used for measuring interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α), IL-13, signal transducer and activator of transcription-3 (STAT-3), myeloperoxidase activity (MPO), reduced glutathione(GSH), and tissue expression of IL-10, tight junction protein zonula occludens (ZO-1), and caspase-3 genes. The combination therapy significantly attenuated progression of UC by decreasing incidence of diarrhea, rectal bleeding, weight loss, IL-13, IL-6, TNF-α, STAT-3, caspase-3, and MPO activity and significantly increased IL-10, ZO-1, colon length, and GSH content, and these effects were more superior to single drugs. These findings showed that combination therapy was able to ameliorate progression of UC and enhance anti-inflammatory effects possibly by restoring IL-10 and ZO-1 levels and limiting IL-6/STAT-3 trans-signaling.

Baicalin alleviates TNBS-induced colitis by inhibiting PI3K/AKT pathway activation

Inflammatory bowel diseases (IBDs) are chronic immunological disorders of the intestinal tract characterized by persistent inflammation. Baicalin, a type of flavonoid, has exhibited a wide range of pharmacological activities, including immunomodulation and anti-inflammation. However, little is known about the therapeutic role of baicalin in IBD. The aim of the present study was to ascertain whether baicalin could be a therapeutic drug of IBD and investigate its specific mechanisms. In the present study, the results revealed that baicalin not only significantly alleviated TNBS-induced colitis by reducing the release of IL-6, TNF-α and IL-1β and increasing the level of IL-10, but promoted the expression of tight-junction proteins ZO-1 and β-catenin, which may have been achieved by blockage of the PI3K/AKT signaling pathway. In vitro, the results demonstrated that baicalin clearly inhibited the release of TNF-α, IL-6 and IL-1β and promoted the expression of IL-10 in LPS-induced HT-29 cells, and significantly decreased LPS-induced HT-29 cell apoptosis by blockage of the PI3K/AKT signaling pathway. In conclusion, the present research revealed for the first time that baicalin acted as a therapeutic drug in IBD by suppression of the PI3K/AKT signaling pathway.

miR-29a-5p/STAT3 Positive Feedback Loop Regulates TETs in Colitis-Associated Colorectal Cancer

BACKGROUND

Interleukin (IL)-6/signal transducers and activators of transcription 3 (STAT3) signaling plays an important role in the development of colitis-associated colorectal cancer (CAC). The mechanism of CAC formation remains unclear, and the relationship between miRNAs and the IL-6/STAT3 signaling pathway in the development of CAC is not well understood. In this study, we investigated the relationship between miR-29a-5p and the IL-6/STAT3 signaling pathway in the development of CAC and alterations in 10-11 translocations (TETs) regulated by this network.

METHODS

miR-29a-5p was screened in a CAC mouse model by high-throughput microarray analysis and investigated in human colorectal cancer tissue samples and colon cell lines by quantitative reverse transcription polymerase chain reaction (Q-RTPCR). The expression of miR-29a and TETs was detected by Q-RTPCR, and the expression of STAT3/P-STAT3 and TET3 was detected via Western blot assay. The expression of TET1 and 5-hydroxymethylcytosine (5hmC) was detected through immunofluorescence.

RESULTS

Our results showed that miR-29a-5p was significantly upregulated and was accompanied by STAT3 activation in the colon tissues of CAC mouse and human colorectal cancer tissues, as compared with normal colon tissues. In contrast, the levels of TETs and 5hmC were decreased. In vitro, overexpression of miR-29a-5p in colonic cell lines (HCT-116 and IEC-6) and RAW264.7 cells increased STAT3 expression, but decreased that of TET3, TET1, and 5hmC. miR-29a-5p downregulation in HCT-116 and IEC-6 cell lines could rescue the expression of STAT3 and TET3. Notably, STAT3 activation induced by IL-6 upregulated miR-29a-5p expression and reduced TET expression in vitro, although STAT3 inhibitor treatment downregulated miR-29a-5p expression, which was induced by IL-6.

CONCLUSIONS

Our studies showed that tumor development occurred with inflammation. The miR-29a-5p/STAT3 signaling axis could play an important role in the development of CAC, and the miR-29a-5p/STAT3 positive feedback loop may amplify the effects of inflammation, lead to decreased levels of TET and 5hmC, and eventually lead to the development of CAC.

Modulation of cytokine patterns and microbiome during pregnancy in IBD

OBJECTIVE

Pregnancy may affect the disease course of IBD. Both pregnancy and IBD are associated with altered immunology and intestinal microbiology. However, to what extent immunological and microbial profiles are affected by pregnancy in patients with IBD remains unclear.

DESIGN

Faecal and serum samples were collected from 46 IBD patients (31 Crohn's disease (CD) and 15 UC) and 179 healthy controls during first, second and third trimester of pregnancy, and prepregnancy and postpartum for patients with IBD. Peripheral blood cytokine profiles were determined by ELISA, and microbiome analysis was performed by sequencing the V4 region of the bacterial 16S rRNA gene.

RESULTS

Proinflammatory serum cytokine levels in patients with IBD decrease significantly on conception. Reduced interleukin (IL)-10 and IL-5 levels but increased IL-8 and interferon (IFN)γ levels compared with healthy controls were seen throughout pregnancy, but cytokine patterns remained stable during gestation. Microbial diversity in pregnant patients with IBD was reduced compared with that in healthy women, and significant differences existed between patients with UC and CD in early pregnancy. However, these microbial differences were no longer present during middle and late pregnancy. Dynamic modelling showed considerable interaction between cytokine and microbial composition.

CONCLUSION

Serum proinflammatory cytokine levels markedly improve on conception in pregnant patients with IBD, and intestinal microbiome diversity of patients with IBD normalises during middle and late pregnancy. We thus conclude that pregnancy is safe and even potentially beneficial for patients with IBD.

Rotavirus Reprograms Multiple Interferon Receptors and Restricts Their Intestinal Antiviral and Inflammatory Functions

Rotaviruses (RV) cause acute severe diarrhea in the absence of substantial intestinal inflammation. They are also highly infectious in their homologous host species. The replication capacity of RV in the small bowel is substantially due to its ability to inhibit different types of interferons (IFNs). Here, we found that during RV infection in vitro, both virus-infected and uninfected bystander cells resist STAT1 phosphorylation and interferon regulatory factor 7 (IRF7) induction in response to exogenous interferon (IFN). Functionally, cellular transcription in response to stimulation with IFN, but not intracellular double-stranded RNA (dsRNA), was inhibited by RV. Further, IFNAR1 stimulation during RV infection significantly repressed a set of virus-induced transcripts. Regulation of IFN signaling in vivo was studied in suckling mice using the highly infectious murine EW RV strain. Kinetic studies indicated that sustained EW RV replication and IFN induction in the small intestine are accompanied by significant decreases in IFN-stimulated transcripts. Lipopolysaccharide (LPS)-mediated intestinal damage, driven by STAT1-induced inflammation, was also prevented in EW RV-infected mice. Remarkably, by ectopically stimulating either IFNAR1 or IFNGR1 in EW RV-infected mice, we could eliminate several intestinal antiviral and inflammatory transcriptional responses to RV. In contrast to infection with homologous RV, infection with a STAT1-sensitive heterologous RV strain induced IFN-stimulated transcripts, inflammatory cytokines, and intestinal expression of STAT1-pY701. Finally, RV strain-specific STAT1 regulation also likely determines the intestinal activation of multiple caspases. The simian RRV strain, but not murine EW RV, uniquely triggers the cleavage of both extrinsic and intrinsic caspases (caspases 8, 9, and 3) in a STAT1-mediated manner. Collectively, our findings reveal efficient reprograming of multiple IFN receptors toward a negative-feedback mode of signaling, accompanied by suppression of IFN-mediated antiviral, apoptotic, and inflammatory functions, during natural RV intestinal infection.IMPORTANCE Rotavirus is a highly infectious pathogen that causes severe diarrhea. Replication of RV in the small intestine is restricted to homologous host species, and host range restriction is substantially determined by the interferon response. In this study, we demonstrate that during infection, RV bystander cells resist exogenous IFN-mediated STAT1 signaling and transcription. In a suckling mouse model, ectopically stimulating different intestinal interferon receptors during RV infection eliminates several innate and inflammatory antiviral responses. Different intestinal inflammatory cytokines were also suppressed by homologous RV, as was intestinal damage in response to endotoxin. The ability of RV to suppress IFN-mediated receptors likely impacts intestinal cell homeostasis, as the cleavage of multiple intestinal caspases during RV infection is mediated by the IFN-STAT1 signaling pathway. Together, our results provide a mechanism underlying both the remarkable interferon resistance of homologous RV and its ability to prevent substantial inflammatory damage to the small bowel.

Dietary cranberry suppressed colonic inflammation and alleviated gut microbiota dysbiosis in dextran sodium sulfate-treated mice

Increased consumption of fruits may decrease the risk of chronic inflammatory diseases including inflammatory bowel disease (IBD). Gut microbiota dysbiosis plays an important etiological role in IBD. However, the mechanisms of action underlying the anti-inflammatory effects of dietary cranberry (Vaccinium macrocarpon) in the colon and its role on gut microbiota were unclear. In this study, we determined the anti-inflammatory efficacy of whole cranberry in a mouse model of dextran sodium sulfate (DSS)-induced colitis, as well as its effects on the structure of gut microbiota. The results showed that dietary cranberry significantly decreased the severity of colitis in DSS-treated mice, evidenced by increased colon length, and decreased disease activity and histologic score of colitis in DSS-treated mice compared to the positive control group (p < 0.05). Moreover, the colonic levels of pro-inflammatory cytokine (IL-1β, IL-6 and TNF-α) were significantly reduced by cranberry supplementation (p < 0.05). Analysis of the relative abundance of fecal microbiota in phylum and genus levels revealed that DSS treatment significantly altered the microbial structure of fecal microbiota in mice. α diversity was significantly decreased in the DSS group, compared to the healthy control group. But, cranberry treatment significantly improved DSS-induced decline in α-diversity. Moreover, cranberry treatment partially reversed the change of gut microbiota in colitic mice by increasing the abundance of potential beneficial bacteria, for example, Lactobacillus and Bifidobacterium, and decreasing the abundance of potential harmful bacteria, such as Sutterella and Bilophila. Overall, our results for the first time demonstrated that modification of gut microbiota by dietary whole cranberry might contribute to its inhibitory effects against the development of colitis in DSS-treated mice.

Polydeoxyribonucleotide Exerts Therapeutic Effect by Increasing VEGF and Inhibiting Inflammatory Cytokines in Ischemic Colitis Rats

Ischemic colitis is resulted from an inadequate blood supply to a segment or entire colon. Polydeoxyribonucleotide (PDRN), extracted from salmon sperm, has been reported to exert anti-inflammatory and anti-ischemic effects through the adenosine A_2A receptor (A_2AR). We investigated whether PDRN possesses therapeutic effectiveness on ischemic colitis rats. Ischemic colitis was induced by selective devascularization. The skin temperature on the ischemic colitis-induced region was determined. To assess the colonic damage score and collagen deposition, colonic tissue sections were stained with hematoxylin and eosin (H&E), and Masson trichrome staining was performed. Western blot analysis for A_2AR, vascular endothelial growth factor (VEGF), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-6, Bax, Bcl-2, and extracellular signal-regulated kinase 1/2 (ERK1/2) was performed. Skin temperature was increased and mucosal damage and collagen deposition were observed in the affected colonic tissues in the ischemic colitis rats. Expressions of inflammatory cytokines (TNF-α, IL-1β, and IL-6) and inflammatory mediator (COX-2) were upregulated in the ischemic colitis rats. Apoptosis was increased by decreasing the ratio of Bcl-2 to Bax and by suppressing the phosphorylated form of ERK1/2 expression in the ischemic colitis rats. Treatment with PDRN alleviated mucosal damage reduced the expressions of inflammatory cytokines and COX-2 and inhibited apoptosis in the ischemic colitis rats. PDRN treatment more enhanced the expressions of A_2AR and VEGF in the ischemic colitis rats. PDRN showed therapeutic effectiveness on ischemic colitis by increasing VEGF expression and inhibiting inflammatory cytokines and COX-2 through enhancing A_2AR expression.

Serum galectins as potential biomarkers of inflammatory bowel diseases

The inflammatory bowel diseases (IBD), which include mainly Crohn’s disease (CD) and ulcerative colitis (UC), are common chronic inflammatory conditions of the digestive system. The diagnosis of IBD relies on the use of a combination of factors including symptoms, endoscopy and levels of serum proteins such as C-reactive protein (CRP) or faecal calprotectin. Currently there is no single reliable biomarker to determine IBD. Galectins are a family of galactoside-binding proteins that are commonly altered in the circulation of disease conditions such as cancer and inflammation. This study investigated serum galectin levels as possible biomarkers in determining IBD and IBD disease activity. Levels of galectins-1, -2, -3, -4, -7 and -8 were analysed in 208 samples from ambulant IBD patients (97 CD, 71 UC) patients and 40 from healthy people. Disease activity was assessed using Harvey-Bradshaw Index for CD and simple clinical colitis activity index for UC. The relationship of each galectin in determining IBD and IBD disease activity were analysed and compared with current IBD biomarker CRP. It was found that serum level of galectin-1 and -3, but not galectins-2, -4, -7 and -8, were significantly higher in IBD patients than in healthy people. At cut-off of 4.1ng/ml, galectin-1 differentiated IBD from healthy controls with 71% sensitivity and 87% specificity. At cut-off of 38.5ng/ml, galectin-3 separated IBD from healthy controls with 53% sensitivity and 87% specificity. None of the galectins however were able to distinguish active disease from remission in UC or CD. Thus, levels of galectins-1 and -3 are significantly elevated in both UC and CD patients compared to healthy people. Although the increased galectin levels are not able to separate active and inactive UC and CD, they may have the potential to be developed as useful biomarkers for IBD diagnosis either alone or in combination with other biomarkers.

Salidroside prevents tumor necrosis factor-α-induced vascular inflammation by blocking mitogen-activated protein kinase and NF-κB signaling activation

Vascular inflammation is a key factor in the pathogenesis of atherosclerosis. Salidroside is an important active ingredient extracted from the root of the Rhodiola rosea plant, which has been reported to have antioxidative, anti-cancer, neuroprotective and cardioprotective effects. However, the effects of salidroside on vascular inflammation have not been clarified. The purpose of the present study was to investigate the protective effects of salidroside against tumor necrosis factor (TNF)-α-induced vascular inflammation in cardiac microvascular endothelial cells (CMECs), a specific cell type derived from coronary micro-vessels. Over a 24-h period, salidroside did not exert any significant cytotoxicity up to a dose of 100 µM. Additionally, salidroside decreased the expression levels of the cell adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) in TNF-α-stimulated CMECs, thus suppressing monocyte-to-CMEC adhesion. Salidroside also decreased the production of inflammatory cytokines such as interleukin (IL)-1β, IL-6 and monocyte chemotactic protein 1 (MCP-1) in TNF-α-induced CMECs, as well as suppressing TNF-α-activated mitogen-activated protein kinase (MAPK) and NF-κB activation. Since MAPKs and NF-κB both serve notable roles in regulating the expression of VCAM-1, IL-1β, IL-6 and MCP-1, the present study provided a preliminary understanding of the mechanism underlying the protective effects of salidroside. Overall, salidroside alleviated vascular inflammation by mediating MAPK and NF-κB activation in TNF-α-induced CMECs. These results indicated that salidroside may have potential applications as a therapeutic agent against vascular inflammation and atherosclerosis.

Rs531564 polymorphism in microRNA-214 regulates interleukin-6R expression in anal fissure patients to affect the risk of anal abscess formation

BACKGROUND

Anal abscess is an important complication of anal fissure (AF), whereas interleukin-6R (IL-6R) has been implicated in the development of abscess. In this study, we aimed to explore the possible molecular mechanisms underlying the regulatory effects of miRNAs on IL-6R and other inflammatory factors related to the induction of anal abscess in AF.

METHODS

Bioinformatics analysis, luciferase assay, real-time polymerase chain reaction, and Western blot analysis were performed to identify the possible regulatory relationships between IL-6R and miR-124/miR-125a by comparing the differentiated expression of miR-125a, miR-124, tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and IL-4 among different groups of AF patients.

RESULTS

IL-6R messenger RNA (mRNA) was identified as a target gene of miR-124 because the luciferase activity in cells cotransfected with wild-type IL-6R and miR-124 mimics was significantly reduced. In addition, the expression of IL-6R mRNA and protein was significantly inhibited in the presence of miR-124 or an IL-6R inhibitor, confirming the presence of a negative regulatory relationship between miR-124 and IL-6R. Moreover, miR-124 and inflammatory factors were differentially expressed in AF patients carrying different genotypes of rs531564 polymorphism.

CONCLUSIONS

miR-124 and inflammatory factors TNF-α, IFN-γ, and IL-4 may be used as indicators of anal abscess development in AF patients. In addition, miR-124 polymorphism rs531564 is involved with the pathogenesis of anal abscess in AF patients, and the presence of rs531564 may increase the incidence of anal abscess via upregulating the expression of IL-6R, TNF-α, IFN-γ, and IL-4.

Mechanisms by Which the Gut Microbiota Influences Cytokine Production and Modulates Host Inflammatory Responses

The gastrointestinal tract encounters a wide variety of microorganisms, including beneficial symbionts, pathobionts, and pathogens. Recent evidence has shown that the gut microbiota, directly or indirectly through its components, such as metabolites, actively participates in the host inflammatory response by cytokine-microbiota or microbiota-cytokine modulation interactions, both in the gut and systemically. Therefore, further elucidation of host cytokine molecular pathways and microbiota components will provide a novel and promising therapeutic approach to control or prevent inflammatory disease and to maintain host homeostasis. The purpose of this review is to summarize well-established scientific findings and provide an updated overview regarding the direct and indirect mechanisms by which the gut microbiota can influence the inflammatory response by modulating the host's cytokine pathways that are mostly involved, but not exclusively so, with gut homeostasis. In addition, we will highlight recent results from our group, which suggest that the microbiota promotes cytokine release from inflammatory cells though activation of microbial metabolite sensor receptors that are more highly expressed on inflammatory and intestinal epithelial cells.

The anti-inflammatory activity of peptides from simulated gastrointestinal digestion of preserved egg white in DSS-induced mouse colitis

Peptides DEDTQAMPFR (DR-10), MLGATSL (ML-7), SLSFASR (SR-7), and MSYSAGF (MF-7) derived from simulated gastrointestinal digestion of preserved egg white (SGD-PEW) exerted anti-inflammatory effects on Caco-2 cells. Here, we aimed to evaluate the anti-inflammatory effects of these peptides derived from SGD-PEW in a mouse model of dextran sodium sulfate (DSS)-induced colitis. The results showed that DR-10, ML-7, SR-7 and MF-7 significantly ameliorated the clinical symptoms of DSS-induced mice colitis, such as weight loss, disease activity index (DAI), colon shortening, spleen hypertrophy and histological scores. Treatment with DR-10, ML-7, SR-7 and MF-7 also significantly inhibited the local secretion of pro-inflammatory cytokines TNF-α and IL-6 and markedly decreased the gene expression of pro-inflammatory cytokines, including TNF-α, IL-6, IL-17, IL-1β, IFN-γ and MCP-1, in DSS-induced mice colitis. Overall, MF-7 showed the best effect of alleviating DSS-induced colitis among the four peptides. These results suggested that MF-7, DR-10, ML-7 and SR-7 may be a potential promising candidate for the treatment of inflammatory bowel disease (IBD).

Beneficial role of Terminalia arjuna hydro-alcoholic extract in colitis and its possible mechanism

ETHNOPHARMACOLOGICAL RELEVANCE

Terminalia arjuna Roxb. (Combretaceae) is traditionally used in Ayurveda medicine and holds ethnomedicinal importance for treatment of gastrointestinal disorders. In view of its anti-inflammatory, antidiarrheal and antioxidant potential, it could be beneficial for the treatment of inflammatory bowel disease (IBD), which is associated with interaction between genetic, environmental factors and intestinal microbiome leading to dysregulated immune responses. This study evaluates the effect of hydroalcoholic extract of Terminalia arjuna bark (TAHA) in trinitrobenzenesulfonic acid (TNBS) model of rat colitis which resembles human IBD.

MATERIALS AND METHODS

TAHA (500, 250, 125 mg/kg) was administered orally for 28 days in TNBS induced rats. Response to treatment was assessed by comparing observations in diseased and treated groups using disease activity index (DAI); macroscopic/histological damage; determining oxidative stress indicators: myeloperoxidase, malondialdehyde, nitric oxide, catalase, superoxide dismutase, and reduced glutathione; gene expression of pro-inflammatory cytokines such as IL-6, IL-1β, TNF-α and chemokine: MCP-1. Furthermore, the role of TAHA in altering the gut microbiota profile in rat feces and plasma zinc was also studied.

RESULTS

TAHA treatment in colitic rats directed decreased DAI scores, macroscopic and histologic damage. It also reduced myeloperoxidase, malondialdehyde and nitric oxide level. Whereas, prevented depletion of plasma catalase, superoxide dismutase and glutathione level. In addition, TAHA treatment down-regulated the gene expression of pro-inflammatory mediators and displayed altered beneficial effect on fecal microbiota. Furthermore, enhanced plasma zinc level supported the beneficial effect of TAHA in colitic rats. The dose of TAHA that produced most significant beneficial effect was 500 mg/kg.

CONCLUSION

TAHA administration relieved the disease activity in TNBS induced colitis by reducing expression of pro-inflammatory cytokines and chemokine, decreasing oxidative stress, and improving plasma zinc level and structure of gut microbiota.

Distinct roles of histamine H1- and H2-receptor signaling pathways in inflammation-associated colonic tumorigenesis

Inflammatory bowel disease (IBD) is a well-known risk factor for the development of colorectal cancer. Prior studies have demonstrated that microbial histamine can ameliorate intestinal inflammation in mice. We tested the hypothesis whether microbe-derived luminal histamine suppresses inflammation-associated colon cancer in Apc^min/+ mice. Mice were colonized with the human-derived Lactobacillus reuteri. Chronic inflammation was induced by repeated cycles of low-dose dextran sulfate sodium (DSS). Mice that were given histamine-producing L. reuteri via oral gavage developed fewer colonic tumors, despite the presence of a complex mouse gut microbiome. We further demonstrated that administration of a histamine H1-receptor (H1R) antagonist suppressed tumorigenesis, while administration of histamine H2-receptor (H2R) antagonist significantly increased both tumor number and size. The bimodal functions of histamine include protumorigenic effects through H1R and antitumorigenic effects via H2R, and these results were supported by gene expression profiling studies on tumor specimens of patients with colorectal cancer. Greater ratios of gene expression of H2R ( HRH2) vs. H1R ( HRH1) were correlated with improved overall survival outcomes in patients with colorectal cancer. Additionally, activation of H2R suppressed phosphorylation of mitogen-activated protein kinases (MAPKs) and inhibited chemokine gene expression induced by H1R activation in colorectal cancer cells. Moreover, the combination of a H1R antagonist and a H2R agonist yielded potent suppression of lipopolysaccharide-induced MAPK signaling in macrophages. Given the impact on intestinal epithelial and immune cells, simultaneous modulation of H1R and H2R signaling pathways may be a promising therapeutic target for the prevention and treatment of inflammation-associated colorectal cancer. NEW & NOTEWORTHY Histamine-producing Lactobacillus reuteri can suppress development of inflammation-associated colon cancer in an established mouse model. The net effects of histamine may depend on the relative activity of H1R and H2R signaling pathways in the intestinal mucosa. Our findings suggest that treatment with H1R or H2R antagonists could yield opposite effects. However, by harnessing the ability to block H1R signaling while stimulating H2R signaling, novel strategies for suppression of intestinal inflammation and colorectal neoplasia could be developed.