Apoptosis as a therapeutic tool in IBD?

Exploring the Underlying Mechanism of Ren-Shen-Bai-Du Powder for Treating Inflammatory Bowel Disease Based on Network Pharmacology and Molecular Docking

Ren-Shen-Bai-Du Powder (RSBDP) is currently used for inflammatory bowel disease (IBD) therapy in China. However, its potential mechanism against IBD remains unknown. In this study, we initially identified potential targets of RSBDP against IBD through network pharmacology analysis and molecular docking. Afterwards, the DSS-induced colitis mice model was employed to assess the effects of RSBDP. The results of network pharmacology indicated that a total of 39 main active ingredients in RSBDP generated 309 pairs of drug-ingredient and ingredient-target correspondences through 115 highly relevant targets of IBD. The primary ingredients (quercetin, kaempferol, luteolin, naringenin, and sitosterol) exerted functions through multiple targets that include CYP1B1, CA4/7, and ESR1/2, etc. GO functional enrichment analysis revealed that the targets related to IBD were significantly enriched in the oxidation-reduction process, protein binding, and cytosol. Per the KEGG pathway analysis, pathways in cancer, adherens junction, and nitrogen metabolism were pivotal in the RSBDP’s treatment of IBD. Additionally, molecular docking demonstrated that a set of active ingredients and their targets displayed good bonding capabilities (e.g., kaempferol and AhR with combined energy < 5 kcal/mol). For the animal experiment, oral RSBDP promoted weight recovery, reduced intestinal inflammation, and decreased serum IL-1, IL-6, and IL-8 concentrations in the DSS + RSBDP group. Meanwhile, oral RSBDP significantly up-regulated the mRNA levels of CA7, CPY1B1, and PTPN11; in particular, the expression level of CYP1B1 in the DSS + RSBDP group was up-regulated by as high as 9-fold compared to the DSS group. Western blot results indicated that the protein levels of AKR1C1, PI3K, AKT, p-AKT, and Bcl-2 were significantly down-regulated, and Bax was significantly up-regulated in the DSS + RSBDP group. Compared to the DSS and control groups, the Bax/Bcl-2 value in the DSS + RSBDP group increased 4-fold and 8-fold, respectively, which suggested that oral RSBDP promotes apoptosis of intestinal epithelial cells. In short, this study established quercetin, kaempferol, luteolin, naringenin, and sitosterol as the primary key active ingredients of RSBDP that exert synergistic therapeutic effects against IBD through modulating the AhR/CYP1B1 and AKR1C1/PI3K/AKT pathways.

Co-administration of Lactobacillus gasseri KBL697 and tumor necrosis factor-alpha inhibitor infliximab improves colitis in mice

Inflammatory bowel disease (IBD) refers to disorders involving chronic inflammation of the gastrointestinal tract. Well-established treatments for IBD have not yet to be suggested. To address this gap, we investigated the effects of co-administration of Lactobacillus gasseri (L. gasseri) KBL697 and infliximab (IFX), the first approved tumor necrosis factor (TNF)-alpha inhibitor, on the dextran sodium sulfate-induced colitis mouse model. 2 × 10⁹ colony-forming units/g of L. gasseri KBL697 were administered to seven-week-old female C57BL/6J mice daily by oral gavage. On day three, IFX (5 mg/kg) suspended in 1 × PBS (200 µL) was intravenously injected in the IFX-treated group and all mice were sacrificed on day nine. Co-administration of L. gasseri KBL697 and IFX improved colitis symptoms in mice, including body weight, disease activity index, colon length, and histology score. Additionally, pro-inflammatory cytokines, such as interferon-gamma, interleukin (IL)-2, IL-6, IL-17A, and TNF were significantly decreased, while IL-10, an anti-inflammatory cytokine, was increased. Expression levels of tight junction genes and CD4 + CD25 + Foxp3 + T regulatory cells in the mesenteric lymph nodes were synergistically upregulated with the combined treatment. Furthermore, co-administered mice displayed altered cecum microbial diversity and composition with increases in the genus Prevotella. Related changes in the predicted amino and nucleic acid metabolic pathways were also evident, along with increased acetate and butyrate level. Therefore, the synergistic effect of L. gasseri KBL697 and IFX co-administration is a possible method of prevention and treatment for IBD.

The Selective 5-HT1A Agonist SR57746A Protects Intestinal Epithelial Cells and Enteric Glia Cells and Promotes Mucosal Recovery in Experimental Colitis

BACKGROUND

Neurotrophic growth factors can stabilize the intestinal barrier by preventing the apoptosis of enteric glial cells (EGCs) and enterocytes. We reasoned that a selective 5-HT1A receptor agonist may have neuroprotective properties in the gut and that topical application of SR57746A might be an effective treatment strategy in inflammatory bowel disease (IBD).

METHODS

The therapeutic potential of 5-HT1A receptor agonist SR57746A in IBD was evaluated in vitro (nontransformed NCM460 colonic epithelial cells, SW480 colorectal carcinoma cells) and in vivo (murine dextran sulfate sodium [DSS] colitis and CD4-T-cell transfer colitis). In vitro, we analyzed the effect of SR57746A on apoptosis in intestinal epithelial cells (IECs) and EGCs, and upon proliferation, migration, and intracellular signaling in IECs. In vivo, the effect of topical application of SR57746 on disease activity and on histological and endoscopic findings was compared with intraperitoneal infliximab and placebo, respectively.

RESULTS

The SR57746A activates PI3-K/AKT- and ERK-signaling in IECs. Depending on ERK- and AKT activation, SR57746A potently prevents apoptosis of IECs without inducing proliferation or migration in these cells. Moreover, SR57746A prevented apoptosis in EGCs in vitro. Topical SR57746A treatment significantly reduced mucosal injury in 2 experimental murine colitis models and was as effective as intraperitoneal infliximab treatment.

CONCLUSIONS

Treatment with SR57746A prevents inflammatory cell damage and apoptosis in IECs and EGCs, similar to the neurotrophic effects of EGCs on IECs. Topical treatment with SR57746A could be a candidate for clinical evaluation in the treatment of IBD.

Suppression of Transmembrane Tumor Necrosis Factor Alpha Processing by a Specific Antibody Protects Against Colitis-Associated Cancer

Soluble tumor necrosis factor-α (sTNF-α) plays an important role in colitis-associated cancer (CAC); however, little is known about transmembrane TNF-α (tmTNF-α). Here, we observed an increase in sTNF-α mainly in colitis tissues from an azoxymethane/dextran sodium sulfate (DSS)-induced CAC mouse model whereas tmTNF-α levels were chiefly increased on epithelial cells at the tumor stage. The ratio of intracolonic tmTNF-α/sTNF-α was negatively correlated with the levels of pro-inflammatory mediators (IL-1β, IL-6, and NO) and M1 macrophages but positively correlated with the infiltration of myeloid-derived suppressor cells, regulatory T cells, and the level of the anti-inflammatory cytokine IL-10, suggesting an anti-inflammatory effect of tmTNF-α. This effect of tmTNF-α was confirmed again by the induction of resistance to LPS in colonic epithelial cell lines NCM460 and HCoEpiC through the addition of exogenous tmTNF-α or transfection of the tmTNF-α leading sequence that lacks the extracellular segment but retains the intracellular domain of tmTNF-α. A tmTNF-α antibody was used to block tmTNF-α shedding after the first or second round of inflammation induction by DSS drinking to shift the time window of tmTNF-α expression ahead to the inflammation stage. Antibody treatment significantly alleviated inflammation and suppressed subsequent adenoma formation, accompanied by increased apoptosis. An antitumor effect was also observed when the antibody was administered at the malignant phase of CAC. Our results reveal tmTNF-α as a novel molecular marker for malignant transformation in CAC and provide a new insight into blocking the pathological process by targeting tmTNF-α processing.

An Escherichia coli strain with extra catalase activity protects against murine colitis by scavenging hydrogen peroxide and regulating regulatory t cell/interleukin-17 pathways

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract whose occurrence is attributed to various factors, including genetic factors, immune response, microbial changes, and oxidative stress. Microbial-targeted therapy has emerged as an alternative to immunosuppressive therapy for IBD.

METHODS

The effects of an atypical commensal Escherichia coli strain harboring an additional catalase gene (compared to typical E. coli strain) on dextran sulfate sodium (DSS)-induced colitis were explored in mice.

RESULTS

The atypical E. coli (atEc) significantly restored body weight, reduced disease activity score, and improved histological scores in mice with colitis. Hydrogen peroxide levels in colitis mice were noticeably decreased when the mice were administered atEc. The proinflammatory cytokine levels were decreased and regulatory T cell numbers were increased after the administration of atEc. The abundance of Firmicutes was significantly recovered, while that of Proteobacteria decreased in atEc -treated mice compared with that in vehicle-treated wild-type mice. To investigate the role of interleukin (IL)-17A in mediating the anti-inflammatory effects of the atEc, IL-17A‒knockout mice were orally administered atEc. Clinical and immune responses and microbial composition were significantly reduced in IL-17A‒knockout mice compared with those in wild-type mice.

CONCLUSIONS

atEc ameliorates colonic inflammation by controlling hydrogen peroxide levels, immune responses (including regulatory T cells and IL-17A), and microbial composition. atEc could be a novel candidate of probiotic for IBD treatment.

Dehydroepiandrosterone alleviates intestinal inflammatory damage via GPR30-mediated Nrf2 activation and NLRP3 inflammasome inhibition in colitis mice

Dehydroepiandrosterone (DHEA) is a popular dietary supplement that has anti-inflammatory, anti-oxidant and immune-regulating role; meanwhile, it also can effective in the protection of inflammation diseases such as inflammatory bowel disease (IBD), but the underlying mechanisms remain elusive. Here, we demonstrated that DHEA inhibits excessive inflammation response and enhances gut barrier function via activating the G protein-coupled receptor 30 (GPR30). GPR30-induced the ERK phosphorylation and p62 accumulation led to the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway, which subsequently inhibited the reactive oxygen species (ROS) overproduction and finally alleviated the intestinal barrier dysfunction. Furthermore, DHEA blocked the p38-induced NLRP3 inflammasome activation in both LPS-stimulated colon epithelial cells and macrophages. In addition, in vivo results showed that DHEA and GPR30 agonist G1 attenuated inflammatory responses and gut barrier dysfunction in colitis mice, while the GPR30 specific inhibitor G15 abrogated these beneficial effects of DHEA. Cumulatively, our study unveiled that DHEA is an effective anti-inflammatory agent and suggested that GPR30 could as a potential target for the treatment of IBD.

Peripheral inflammatory biomarkers define biotypes of bipolar depression

We identified biologically relevant moderators of response to tumor necrosis factor (TNF)-α inhibitor, infliximab, among 60 individuals with bipolar depression. Data were derived from a 12-week, randomized, placebo-controlled clinical trial secondarily evaluating the efficacy of infliximab on a measure of anhedonia (i.e., Snaith-Hamilton Pleasure Scale). Three inflammatory biotypes were derived from peripheral cytokine measurements using an iterative, machine learning-based approach. Infliximab-randomized participants classified as biotype 3 exhibited lower baseline concentrations of pro- and anti-inflammatory cytokines and soluble TNF receptor-1 and reported greater pro-hedonic improvements, relative to those classified as biotype 1 or 2. Pretreatment biotypes also moderated changes in neuroinflammatory substrates relevant to infliximab's hypothesized mechanism of action. Neuronal origin-enriched extracellular vesicle (NEV) protein concentrations were reduced to two factors using principal axis factoring: phosphorylated nuclear factorκB (p-NFκB), Fas-associated death domain (p-FADD), and IκB kinase (p-IKKα/β) and TNF receptor-1 (TNFR1) comprised factor "NEV1," whereas phosphorylated insulin receptor substrate-1 (p-IRS1), p38 mitogen-activated protein kinase (p-p38), and c-Jun N-terminal kinase (p-JNK) constituted "NEV2". Among infliximab-randomized subjects classified as biotype 3, NEV1 scores were decreased at weeks 2 and 6 and increased at week 12, relative to baseline, and NEV2 scores increased over time. Decreases in NEV1 scores and increases in NEV2 scores were associated with greater reductions in anhedonic symptoms in our classification and regression tree model (r² = 0.22, RMSE = 0.08). Our findings provide preliminary evidence supporting the hypothesis that the pro-hedonic effects of infliximab require modulation of multiple TNF-α signaling pathways, including NF-κB, IRS1, and MAPK.

Influence of the Treatment Used in Inflammatory Bowel Disease on the Protease Activities

Introduction

There is growing evidence that intestinal proteases have a role in the pathogenesis of gastrointestinal inflammatory diseases. Inflammatory bowel disease (IBD), which includes Crohn’s disease (CD) and ulcerative colitis (UC), has an additional source of proteases represented by infiltrated and activated inflammatory cells. The aim of our study was to determine proteolytic system activity in patients with CD and UC. We limited the number of proteases tested by determining proteases active in acidic, neutral and alkaline pH.

Materials and Methods

The study included 40 patients with IBD – 20 CD patients and 20 UC patients. The control group consisted of 20 healthy subjects. Among the 20 CD patients, 17 were treated with aminosalicylates, 14 with azathioprine, and 4 with corticosteroids, while 8 patients were undergoing biological treatment. Among the 20 UC patients, 19 were treated with aminosalicylates, 8 with azathioprine, and 3 with corticosteroids. The total protein concentration was assayed by the Lowry method. The optimal pH was assayed in pH from 2.2 to 12.8, separated by 0.2 intervals. Proteolytic activities were determined against different substrates (gelatine, haemoglobin, ovalbumin, albumin, cytochrome C, and casein), and haemoglobin was the optimal substrate. Protease activities were determined according to Anson method. Determination of the activities of natural inhibitors of acidic, neutral and alkaline proteases is based on the Lee and Lin method.

Results

Decreases were observed in the activities of acid proteases (pH 5), alkaline proteases (pH 7), and neutral proteases (pH 7.6 and 8.6) in the groups of CD patients in remission in comparison with the active phase. In the group of patients with biologically treated CD patients, acid protease activity (pH 5.0) was lower than in CD patients not receiving biological treatment. Activities of neutral (pH 7.0) and alkaline (pH 7.6 and 8.6) proteases in the plasma of patients with UC in remission were lower in comparison to the active phase. Activities of acid (pH 5.0) and alkaline (8.6) protease inhibitors were higher in CD patients in the active phase in comparison to remission. In UC patients with exacerbation of the disease, the activity of alkaline (pH 8.6) protease inhibitors was increased compared to remission.

Conclusion

1. Our research may suggest that the immunomodulatory treatment used in IBD, aimed at reducing the level of leukocytes and reduction of inflammation, may contribute to a reduction in protease activity. 2. The decrease of protease activities in patients with CD and UC in remission may be a marker suggesting the patients’ response to the treatment.

Melatonin controls microbiota in colitis by goblet cell differentiation and antimicrobial peptide production through Toll-like receptor 4 signalling

Microbial dysbiosis has long been postulated to be associated with the pathogenesis of inflammatory bowel disease (IBD). Although evidence supporting the anti-colitic effects of melatonin have been accumulating, it is not clear how melatonin affects the microbiota. Herein, we investigated the effects of melatonin on the microbiome in colitis and identified involvement of Toll-like receptor (TLR) 4 signalling in the effects. Melatonin improved dextran sulfate sodium (DSS)-induced colitis and reverted microbial dysbiosis in wild-type (WT) mice but not in TLR4 knockout (KO) mice. Induction of goblet cells was observed with melatonin administration, which was accompanied by suppression of Il1b and Il17a and induction of melatonin receptor and Reg3β, an antimicrobial peptide (AMP) against Gram-negative bacteria. In vitro, melatonin treatment of HT-29 intestinal epithelial cells promotes mucin and wound healing and inhibits growth of Escherichia coli. Herein, we showed that melatonin significantly increases goblet cells, Reg3β, and the ratio of Firmicutes to Bacteriodetes by suppressing Gram-negative bacteria through TLR4 signalling. Our study suggests that sensing of bacteria through TLR4 and regulation of bacteria through altered goblet cells and AMPs is involved in the anti-colitic effects of melatonin. Melatonin may have use in therapeutics for IBD.

Semaphorin 3E regulates apoptosis in the intestinal epithelium during the development of colitis

Semaphorin 3E (SEMA3E) has emerged as an axon-guiding molecule that regulates various biological processes including the immune responses and apoptosis. However, its role in the pathophysiology of colitis remains elusive. We investigated the role of SEMA3E in intestinal epithelial cells (IECs) activation, using biopsies from patients with active ulcerative colitis (UC), a mouse model of UC, and an in-vitro model of intestinal mucosal healing. In this study, we confirmed that the mRNA level of SEMA3E is reduced significantly in patients with UC and demonstrated a negative linear association between SEMA3E mRNA and p53-associated genes. In mice, genetic deletion of Sema3e resulted in an increase onset and severity of colitis, p53-associated genes, apoptosis, and IL-1beta production. Recombinant SEMA3E treatment protected against colitis and decreased these effects. Furthermore, in stimulated epithelial cells, recombinant SEMA3E treatment enhanced wound healing, resistance to oxidative stress and decreased apoptosis and p53-associated genes. Together, these findings identify SEMA3E as a novel regulator in intestinal inflammation that regulates IECs apoptosis and suggest a potential novel approach to treat UC.

Lactobacillus acidophilus suppresses intestinal inflammation by inhibiting endoplasmic reticulum stress

BACKGROUND AND AIM

Nuclear factor kappa B (NF-κB) activation and endoplasmic reticulum (ER) stress signaling play significant roles in the pathogenesis of inflammatory bowel disease (IBD). Thus, we evaluated whether new therapeutic probiotics have anti-colitic effects, and we investigated their mechanisms related to NF-κB and ER-stress pathways.

METHODS

Luciferase, nitric oxide, and cytokine assays using HT-29 or RAW264.7 cells were conducted. Mouse colitis was induced using dextran sulfate sodium and confirmed by disease activity index and histology. Macrophages and T-cell subsets in isolated peritoneal cavity cells and splenocytes were analyzed by flow cytometry. Gene and cytokine expression profiles were determined using reverse-transcription polymerase chain reaction.

RESULTS

Lactobacillus acidophilus (LA1) and Pediococcus pentosaceus inhibited nitric oxide production in RAW264.7 cells, but only LA1 inhibited Tnfa and induced Il10 expression. LA1 increased the lifespan of dextran sulfate sodium-treated mice and attenuated the severity of colitis by inducing M2 macrophages in peritoneal cavity cells and Th2 and Treg cells in splenocytes. The restoration of goblet cells in the colon was accompanied by the induction of Il10 expression and the suppression of pro-inflammatory cytokines. Additionally, we found that LA1 exerts an anti-colitic effect by improving ER stress in HT-29 cells as well as in vivo.

CONCLUSIONS

We showed that LA1 significantly interferes with ER stress and suppresses NF-κB activation. Our findings suggest that LA1 can be used as a potent immunomodulator in IBD treatment, and the regulation of ER stress may have significant implications in treating IBD.

Soya-saponins induce intestinal inflammation and barrier dysfunction in juvenile turbot (Scophthalmus maximus)

Soybean meal-induced enteritis (SBMIE) is a well-described condition in the distal intestine (DI) of several cultured fish species, but the exact cause is still unclear. The work on Atlantic salmon and zebrafish suggested soya-saponins, as heat-stable anti-nutritional factors in soybean meal, are the major causal agents. However, this conclusion was not supported by the research on some other fish, such as gilthead sea bream and European sea bass. Our previous work proved that soybean could induce SBMIE on turbot and the present work aimed to investigate whether soya-saponins alone could cause SBMIE and the effects of soya-saponins on the intestinal barrier function in juvenile turbot. Turbots with initial weight 11.4 ± 0.02 g were fed one of four fishmeal-based diets containing graded levels of soya-saponins (0, 2.5, 7.5, 15 g kg-1) for 8 weeks. At the end of the trial, all fish were weighed and plasma was obtained for diamine oxidase (DAO) activity and d-lactate level analysis and DI was sampled for histological evaluation and quantification of antioxidant parameters and inflammatory marker genes. The activities of superoxide dismutase, catalase, glutathione peroxidase, glutathione reductase and intestinal glutathione level were selected to evaluated intestinal antioxidant system. The distal intestinal epithelial cell (IEC) proliferation and apoptosis were investigated by proliferating cell nuclear antigen (PCNA) labelling and TdT-mediated dUTP nick end labeling (TUNEL), respectively. The results showed that soya-saponins caused significantly dose-dependent decrease in the growth performance and nutrient utilization (p < 0.05). Enteritis developed in DI of the fish fed diet containing soya-saponins. Significantly dose-dependent increases in severity of the inflammation concomitant with up-regulated expression of il-1β, il-8, and tnf-α, increased IEC proliferation and apoptosis, and decreases in selected antioxidant parameters were detected (p < 0.05). The epithelial permeability (evaluated by the plasma DAO activity and d-lactate level) was significantly increased with the increasing of dietary level of soya-saponins (p < 0.05), which was concomitant with the destroyed the intracellular junctions. In conclusion, the present work proved that soya-saponins induced enteritis and compromised the intestinal barrier functions. Based on the present work, strategies focus on regulation of cell apoptosis, epithelial permeability, intracellular junctions and redox homeostasis worth further investigating to develop new and efficient ways for SBMIE alleviation.

Clinical Course of Ulcerative Colitis After Liver Transplantation in Patients with Concomitant Primary Sclerosing Cholangitis and Ulcerative Colitis

BACKGROUND

The natural history of ulcerative colitis (UC) after liver transplantation (LT) for primary sclerosing cholangitis (PSC) remains ill defined. This study aimed to evaluate the course of UC after LT for PSC.

METHODS

The course of UC, including the clinical colitis severity index, was evaluated in patients with concomitant PSC and UC who received LT for PSC-induced end-stage liver disease. A total of 167 (55.4%) patients with PSC had concurrent inflammatory bowel disease (IBD). Of 159 cases of IBD that started before LT, 152 (95.5%) had UC and 7 (4.5%) had Crohn's disease.

RESULTS

The mean duration of patient follow-up after LT was 47.7 ± 33.5 months. The simple clinical colitis activity index scores after LT showed no change in 15.8% of patients, decreased in 78.3%, and increased in 5.9%. Seventy-one (46.7%) patients required no change in their specific UC treatment after LT, whereas 12 (7.9%) had to use more aggressive treatments after LT. In 69 (45.4%) patients, treatment could be tapered although not discontinued. Multiple logistic regression analysis demonstrated that the duration of LT (odds ratio = 1.02; 95% confidence interval, 1.00-1.05, P = 0.03) was significantly associated with aggravation in the clinical course of UC after LT. Posttransplant cyclosporine exposure (odds ratio = 0.14; 95% confidence interval, 0.015-0.79, P = 0.028) and pretransplant body weight (odds ratio = 0.81; 95% confidence interval, 0.71-0.93, P = 0.003) demonstrated a protective effect.

CONCLUSIONS

Although the clinical course of UC remains unchanged or even improves in the majority of patients after LT, some may experience an aggressive course. The type of immunosuppression after transplantation can affect UC activity after LT. Cyclosporine may have some protective effects post-LT.

2016 Infectious Diseases Society of America (IDSA) Clinical Practice Guideline for the Treatment of Coccidioidomycosis

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. Infectious Diseases Society of America considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.Coccidioidomycosis, also known as San Joaquin Valley fever, is a systemic infection endemic to parts of the southwestern United States and elsewhere in the Western Hemisphere. Residence in and recent travel to these areas are critical elements for the accurate recognition of patients who develop this infection. In this practice guideline, we have organized our recommendations to address actionable questions concerning the entire spectrum of clinical syndromes. These can range from initial pulmonary infection, which eventually resolves whether or not antifungal therapy is administered, to a variety of pulmonary and extrapulmonary complications. Additional recommendations address management of coccidioidomycosis occurring for special at-risk populations. Finally, preemptive management strategies are outlined in certain at-risk populations and after unintentional laboratory exposure.

Disturbances in apoptosis of lamina propria lymphocytes in Crohn's disease

INTRODUCTION

The aim of this study was to assess the potential mechanisms providing resistance to apoptosis of lamina propria lymphocytes (LPL) directlyin intestinal tissues from patients with Crohn's disease (CD).

MATERIAL AND METHODS

Fifty CD patients were enrolled in the study. The control group consisted of healthy patients who underwent surveillance colonoscopy after endoscopic polypectomy. Each CD patient underwent colonoscopy with tissue sampling from inflamed areas of the colon with the assessment of immunohistochemical expression of active caspase 3, Fas, tumour necrosis factor receptor 1 (TNFR1), Bcl-2, Bax, CD4 and CD8. This was compared with healthy intestinal mucosa.

RESULTS

The expression of active caspase 3 was significantly lower in LPL in CD (0.4 ±0.3 vs. 2.8 ±1.5; p = 0.0002). A statistically significant increase of CD4 and CD8 positive cells was noted in CD (2.3 ±0.5 vs. 1.2 ±0.2, p < 0.0001; 2.1 ±0.3 vs. 1.1 ±0.3, p < 0.0001, respectively). It was associated with a significant increase of the Bcl-2 (6.7 ±2.7 vs. 2.9 ±0.8; p < 0.0001) and a decrease of the Bax protein expression (3.4 ±2.1 vs. 5.5 ±1.8; p < 0.0001) in CD. The expression of Fas and TNFR1 did not differ between the study groups.

CONCLUSIONS

LPL in CD are resistant to apoptosis when compared with physiological conditions. This is probably due to an imbalance in Bcl-2 family proteins. TNFR1-related pathway is probably not involved in disturbances of LPL apoptosis in CD.

Monocyte and M1 Macrophage-induced Barrier Defect Contributes to Chronic Intestinal Inflammation in IBD

BACKGROUND

Macrophages are key players in inflammatory bowel diseases (IBD). This study aimed to determine site-specific effects of defined macrophage subtypes on the integrity of the intestinal epithelial barrier.

METHODS

Macrophage subtypes in situ in intestinal specimens of patients with IBD were visualized by immunohistochemistry. In vitro polarization of human peripheral CD14 cells yielded M1 or M2 macrophages. The influence of primary monocytes or macrophage subtypes on epithelial barrier integrity was analyzed by transepithelial resistance measurements, Western blot analysis, confocal laser scanning microscopy, and cytometric bead array in a coculture model of primary human macrophages and layers of intestinal epithelial cell lines.

RESULTS

The lamina propria of the inflamed intestine in patients with IBD, predominantly in Crohn's disease, is massively infiltrated by CD68 cells also positive for inducible nitric oxide synthase and tumor necrosis factor (TNF) α. The presence of M1 macrophage shifted the balance in the local macrophage compartment towards a proinflammatory state. In the coculture model, monocytes and M1 macrophages reduced transepithelial resistance as a marker for epithelial barrier integrity. The mechanisms for paracellular leakage included intracellular relocalization of tight junction proteins like claudin-2 and epithelial cell apoptosis. Determined by specific cytokine blockade, M1 macrophages exerted their deleterious effect mainly through TNF-α, whereas monocyte-mediated damage was driven by the inflammasome effector cytokines, interleukin-1β and interleukin-18.

CONCLUSIONS

Lamina propria monocytes and M1 macrophages invading intestinal tissues directly contribute to disrupting the epithelial barrier through deregulation of tight junction proteins and induction of epithelial cell apoptosis, thus driving intestinal inflammation in IBD.

Involvement of heat shock protein a4/apg-2 in refractory inflammatory bowel disease

BACKGROUND

Expression of heat shock protein A4 (HSPA4, also called Apg-2), a member of the HSP110 family, is induced by several forms of stress. The physiological and pathological functions of HSPA4 in the intestine remain to be elucidated.

METHODS

We assessed HSPA4 expression and function by generating HSPA4-deficient mice and using 214 human intestinal mucosa samples from patients with inflammatory bowel disease (IBD).

RESULTS

In the colonic mucosa of patients with IBD, a significant correlation was observed between the expression of HSPA4 and antiapoptotic protein Bcl-2, a T-cell-derived cytokine IL-17 or stem cell markers, such as Sox2. In refractory ulcerative colitis, a condition associated with increased cancer risk, expression of HSPA4 and Bcl-2 was increased in inflammatory cells of colonic mucosae. HSPA4 was overexpressed both in cancer cells and immune cells of human colorectal cancers. Patients with high expression of HSPA4 or Bmi1 showed significantly lower response rates upon subsequent steroid therapy as compared with patients with low expression of each gene. HSPA4-deficient mice exhibit more apoptosis and less expression of IL-17/IL-23 in inflammatory cells and less number of Sox2 cells after administration of dextran sodium sulfate than control mice. Transduction of HspaA4 bone marrow into wild-type mice reduced the immune response.

CONCLUSIONS

Upregulation of Bcl-2 and IL-17 by HSPA4 would control apoptosis of inflammatory cells and immune response in the gut, which might develop treatment resistance in IBD. HSPA4 and Bmi1 would be a useful biomarker for refractory clinical course and a promising approach for a therapeutic strategy in patients with IBD.

Tumor necrosis factor suppresses NR5A2 activity and intestinal glucocorticoid synthesis to sustain chronic colitis

Intestinal crypt epithelial cells synthesize glucocorticoids, steroid hormones that protect against inflammatory bowel disease. To investigate how intestinal glucocorticoids are regulated during chronic inflammation, we induced chronic colitis in mice by exposing them to the chemical dextran sulfate sodium (DSS). We found that intestinal glucocorticoid secretion and expression of the genes Cyp11a1 and Cyp11b1 (which encode enzymes that synthesize glucocorticoids) were initially stimulated, but declined during the chronic phase, whereas tumor necrosis factor (TNF) and inflammatory cytokines secreted by T helper type 1 (TH1) and TH17 cells continuously increased in abundance in the inflamed colon. This suggested that inadequate intestinal glucocorticoid synthesis is a feature of chronic intestinal inflammation. We screened for cytokines that regulated intestinal glucocorticoid synthesis and found that TNF suppressed corticosterone secretion and Cyp11a1 and Cyp11b1 expression in an intestinal crypt epithelial cell line. TNF suppressed steroidogenesis by activating the transcription factors c-Jun and nuclear factor κB (NF-κB), which both interacted with the transcription factor NR5A2 and repressed Cyp11a1 reporter activity. This repression was relieved by expression of a dominant-negative form of c-Jun amino-terminal kinase 1 (JNK1), inhibitor of NF-κB, or by a JNK inhibitor. Furthermore, the dominant-negative TNF inhibitor XPro1595 inhibited c-Jun and NF-κB activation in mice, restored intestinal Cyp11a1 and Cyp11b1 expression, reduced colonic cell death, and rescued chronic colitis caused by DSS. Thus, during chronic colitis, TNF suppresses intestinal steroidogenic gene expression by inhibiting the activity of NR5A2, thus decreasing glucocorticoid synthesis and sustaining chronic inflammation.

Bcl-2/caspase 3 mucosal imbalance favors T cell resistance to apoptosis in dogs with inflammatory bowel disease

Canine idiopathic inflammatory bowel disease (IBD) is believed to result from complex interplay between genetic, microbial, and immunologic factors. Abnormal cell death by apoptosis may result in the persistence of activated intestinal T cells that contribute to mucosal inflammation and clinical severity. To test this hypothesis, we investigated the mucosal expression of pro- and anti-apoptotic proteins in different intestinal compartments and their association with inflammatory indices in dogs with IBD. Apoptosis of lamina propria (LP) T cells in duodenal, ileal, and colonic tissues in control and IBD dogs was analyzed by caspase 3/Bcl-2 immunohistochemistry and TUNEL assays. Densities and distributions of LP caspase 3 and Bcl-2 cells were correlated to histopathologic lesions and the clinical activity index (CIBDAI). Compared to control tissues, IBD dogs had significantly (P<0.01) fewer caspase 3 cells in colonic mucosa. Double immunostaining identified the majority of apoptotic cells as TUNEL(+)/caspase 3(+). Within intestinal mucosa of IBD dogs, there were significantly greater numbers of Bcl-2 cells at the apical and basilar villus in the duodenum as compared to the colon and to the apical and basilar villus in the ileum (P<0.001 for all comparisons). There were significantly greater numbers of Bcl-2 cells at the apical and basilar villus of the duodenum but significantly fewer numbers of Bcl-2 cells at the apical villus of the ileum in IBD dogs compared with controls (P<0.001, P<0.001, and P<0.02, respectively). There was a significant association between the number of Bcl-2 cells in the duodenum of IBD dogs and the CIBDAI (P<0.001 each for mild, moderate and severe clinical IBD). In conclusion, apoptosis of T lymphocytes varies within intestinal compartments of dogs with IBD. Mucosal imbalance of Bcl-2/caspase 3 expression favors T cell resistance to apoptosis which may contribute to T cell accumulation and chronic intestinal inflammation, similar to human IBD.

The value of experimental models of colitis in predicting efficacy of biological therapies for inflammatory bowel diseases

During the last decade, biological therapies have an increasing share in the modern therapeutics of various diseases including inflammatory bowel diseases (IBD). Animal models of IBD have often been used to identify the targets of biological therapies, to test their relevance to disease pathogenesis, to assess their therapeutic efficacy in vivo, and to check for drug toxicity. In the field of inflammatory diseases the majority of biologics under development have failed to reach the clinic. This review examines the ability of preclinical data from animal models of IBD to predict success or failure of biologics in human IBD. Specifically, it describes the murine models of IBD, the mechanism of disease induction, the phenotype of the disease, its relevance to human IBD, and the specific immunological features of disease pathogenesis in each model and mainly compares the results of the phase II and III trials of biologics in IBD with preclinical data obtained from studies in animal models. Finally, it examines the possible reasons for low success in translation from bench to bedside and offers some suggestions to improve translation rates.

The influence of infliximab and adalimumab on the expression of apoptosis-related proteins in lamina propria mononuclear cells and enterocytes in Crohn's disease - an immunohistochemical study

BACKGROUND AND AIMS

The aim of this study was to assess the influence of anti-TNF agents on the expression of apoptosis-related proteins in Crohn's disease (CD) patients.

METHODS

The clinical, biochemical and endoscopic activity of CD was assessed with the use of tissue sampling before the initiation of therapy and after induction doses of infliximab and adalimumab. Additionally, the immunohistochemical expression of active caspase 3, TNFR1, Fas, Bcl-2, Bax, CD4 and CD8 proteins was estimated. Patients achieving deep remission were considered as responders.

RESULTS

Of the 35 patients qualified for the study, 60% achieved deep remission. In those patients, a significant decrease in the number of CD4 and CD8 positive cells was noted. Also observed was a significant increase in the expression of active caspase 3 in lamina propria mononuclear cells, which correlated with an increase of the pro-apoptotic Bax/Bcl-2 ratio. No change in Fas and TNFR1 expression was observed in those cells. Moreover, there was a significant decrease in active caspase 3 expression in enterocytes, observed independently of the Bax/Bcl-2 ratio. This correlated with a change in TNFR1 expression. No significant changes in the expression of the investigated proteins were noted in non-responders group.

CONCLUSIONS

The efficacy of anti-TNF antibodies is, at least partly, dependent on apoptosis modulation. In lamina propria mononuclear cells, the increase of apoptosis is probably the result of the induction of the intrinsic pathway mediated by Bcl-2 family proteins. In enterocytes - the decrease of apoptosis is mediated by the extrinsic pathway, probably via TNFR1.

Periodontal disease immunology: 'double indemnity' in protecting the host

During the last two to three decades our understanding of the immunobiology of periodontal disease has increased exponentially, both with respect to the microbial agents triggering the disease process and the molecular mechanisms of the host engagement maintaining homeostasis or leading to collateral tissue damage. These foundational scientific findings have laid the groundwork for translating cell phenotype, receptor engagement, intracellular signaling pathways and effector functions into a 'picture' of the periodontium as the host responds to the 'danger signals' of the microbial ecology to maintain homeostasis or succumb to a disease process. These findings implicate the chronicity of the local response in attempting to manage the microbial challenge, creating a 'Double Indemnity' in some patients that does not 'insure' health for the periodontium. As importantly, in reflecting the title of this volume of Periodontology 2000, this review attempts to inform the community of how the science of periodontal immunology gestated, how continual probing of the biology of the disease has led to an evolution in our knowledge base and how more recent studies in the postgenomic era are revolutionizing our understanding of disease initiation, progression and resolution. Thus, there has been substantial progress in our understanding of the molecular mechanisms of host-bacteria interactions that result in the clinical presentation and outcomes of destructive periodontitis. The science has embarked from observations of variations in responses related to disease expression with a focus for utilization of the responses in diagnosis and therapeutic outcomes, to current investigations using cutting-edge fundamental biological processes to attempt to model the initiation and progression of soft- and hard-tissue destruction of the periodontium. As importantly, the next era in the immunobiology of periodontal disease will need to engage more sophisticated experimental designs for clinical studies to enable robust translation of basic biologic processes that are in action early in the transition from health to disease, those which stimulate microenvironmental changes that select for a more pathogenic microbial ecology and those that represent a rebalancing of the complex host responses and a resolution of inflammatory tissue destruction.

Effects of aging on apoptosis gene expression in oral mucosal tissues

Apoptotic processes are important for physiologic renewal of an intact epithelial barrier and contribute some antimicrobial resistance for bacteria and viruses, as well as anti-inflammatory effects that benefits the mucosa. The oral cavity presents a model of host-bacterial interactions at mucosal surfaces, in which a panoply of microorganisms colonizes various niches in the oral cavity and creates complex multispecies biofilms that challenge the gingival tissues. This report details gene expression in apoptotic pathways that occur in oral mucosal tissues across the lifespan, using a nonhuman primate model. Macaca mulatta primates from 2 to 23 years of age (n = 23) were used in a cross-sectional study to obtain clinical healthy gingival tissues specimens. Further, mRNA was prepared and evaluated using the Affymetrix Rhesus GeneChip and 88 apoptotic pathway genes were evaluated. The results identified significant positive correlations with age in 12 genes and negative correlations with an additional five genes. The gene effects were predicted to alter apoptosis receptor levels, extrinsic apoptotic pathways through caspases, cytokine effects on apoptotic events, Ca(+2)-induced death signaling, cell cycle checkpoints, and potential effects of survival factors. Both the positively and negatively correlated genes within the apoptotic pathways provided evidence that healthy tissues in aging animals exhibit decreased apoptotic potential compared to younger animals. The results suggested that decreased physiologic apoptotic process in the dynamic septic environment of the oral mucosal tissues could increase the risk of aging tissues to undergo destructive disease processes through dysregulated inflammatory responses to the oral microbial burden.

The impact of inflammatory bowel disease post-liver transplantation for primary sclerosing cholangitis

BACKGROUND

An association between primary sclerosing cholangitis (PSC) and inflammatory bowel disease (IBD) is well recognized. However, the disease course of IBD following liver transplantation (LT) for PSC remains ill-defined.

AIMS AND METHODS

We aimed to assess the impact of IBD in patients that had undergone LT for PSC to help identify risk factors for flare and to assess the impact of IBD on graft survival.

RESULTS

110 patients underwent LT for PSC (Oct 1990-Aug 2009) at King's College Hospital. 74 (67%) patients had concurrent IBD and 36 had PSC alone prior to transplant. 39 patients developed IBD (flare of IBD and de-novo) post transplant. Cumulative risk for IBD at 1-, 2-, 5- and 10-years was 16%, 24%, 38% and 72% respectively. Flare of IBD occurred in 33 patients with a mean time to flare of 30 ± 28 months. De-novo IBD occurred in 6 patients (all UC). Mean time to diagnosis was 29 ± 25 months. Multivariate cox-regression analysis identified active IBD at time of LT as a significant predictor of graft failure post LT (HR 10, CI 3-39, P = 0.001) and smoking at time of transplantation and subsequent cessation predictive of recurrent IBD post transplantation (HR 17, 2-180, P = 0.02).

CONCLUSION

In conclusion, smoking at time of LT was predictive of flare of IBD and active IBD at time of transplantation had a significant effect on graft survival. Medical therapy needs to be maximised in the pre-LT period. Patients with poorly controlled IBD refractory to medical therapy should be considered for colectomy at time of transplantation.

Therapeutic effect of antisecretory factor-rich egg yolk on the late phases of 2,4,6-trinitrobenzenesulphonic acid colitis in mice

Antisecretory factor (AF) is expressed in all tissues of mammals, inhibits intestinal hypersecretion and has anti-inflammatory properties as well. Endogenous AF synthesis may be stimulated by feeding hydrothermally processed cereals. Alternatively, freeze-dried egg yolk can be used as a source of exogenous AF. Several reports have suggested that AF from freeze-dried egg yolk may be useful in inflammatory bowel disease. We assessed the effect of freeze-dried, AF-rich egg yolk intake on 2,4,6-trinitrobenzenesulphonic acid (TNBS) colitis. Balb/c mice were randomised to receive (1) AF in sterile drinking-water (4 g/l, n 38) and (2) sterile drinking-water alone (vehicle, n 38) from TNBS or saline administration onwards. Different subsets of mice were killed at weeks 1-3 after TNBS or saline administration. Macroscopic and microscopic damage was assessed in colonic specimens. Eicosanoid and cytokine production was evaluated in supernatants of 24 h-incubated colonic explants. Myeloperoxidase activity was measured in frozen colonic samples, while apoptosis was assessed in paraffined samples by the in situ oligoligation method. AF-treated mice showed a milder colonic damage compared with the vehicle group, which became statistically significant at week 3. This was accompanied by decreased IL-2, IL-1 and leukotriene B4 production at weeks 2 and 3, as well as increased interferon-γ at week 1, in AF-treated mice compared with vehicle-treated mice. AF-treated mice had significantly increased counts of apoptotic cells in the lamina propria at weeks 1 and 2 post-TNBS. In conclusion, the administration of AF-rich egg yolk has a therapeutic effect in the late phases of TNBS colitis in Balb/c mice.

Apoptotic genes are differentially expressed in aged gingival tissue

Cellular and molecular changes of the periodontium associated with a higher prevalence of oral diseases (e.g., chronic periodontitis) in aged populations have received little attention. Since impaired apoptosis during aging appears to be related to chronic inflammatory disorders, we hypothesized that the expression of genes associated with apoptotic processes are altered in aged healthy and periodontitis-affected gingival tissue. Ontology analysis of 88 genes related to apoptotic pathways was performed in gingival biopsies of healthy and periodontitis sites from young, adult, and aged non-human primates (Macaca mulatta), using the GeneChip® Rhesus Macaque Genome Array. Lower expression of anti-apoptotic and higher expression of pro-apoptotic genes were associated with healthy gingival tissue from young compared with aged animals. Few differences in gene expression were observed in healthy gingival tissue between adult and aged animals. Comparison between healthy and periodontitis gingival tissues showed that the up- or down-regulated apoptotic genes in diseased gingival tissue are different in adults compared with aged animals. These results suggest that apoptotic events normally occurring in gingival tissues could be reduced in aging,and unique aspects of apoptotic pathways are potentially involved in the pathophysiology of periodontal disease in adult vs. aged gingival tissues.

Inflammatory bowel disease

Insights into inflammatory bowel disease (IBD) are advancing rapidly owing to immunologic investigations of a plethora of animal models of intestinal inflammation, ground-breaking advances in the interrogation of diseases that are inherited as complex genetic traits, and the development of culture-independent methods to define the composition of the intestinal microbiota. These advances are bringing a deeper understanding to the genetically determined interplay between the commensal microbiota, intestinal epithelial cells, and the immune system and the manner in which this interplay might be modified by relevant environmental factors in the pathogenesis of IBD. This review examines these interactions and, where possible, potential lessons from IBD-directed, biologic therapies that may allow for elucidation of pathways that are central to disease pathogenesis in humans.

Inflammatory bowel disease

Insights into inflammatory bowel disease (IBD) are advancing rapidly owing to immunologic investigations of a plethora of animal models of intestinal inflammation, ground-breaking advances in the interrogation of diseases that are inherited as complex genetic traits, and the development of culture-independent methods to define the composition of the intestinal microbiota. These advances are bringing a deeper understanding to the genetically determined interplay between the commensal microbiota, intestinal epithelial cells, and the immune system and the manner in which this interplay might be modified by relevant environmental factors in the pathogenesis of IBD. This review examines these interactions and, where possible, potential lessons from IBD-directed, biologic therapies that may allow for elucidation of pathways that are central to disease pathogenesis in humans.

Preferential promotion of apoptosis of monocytes by Lactobacillus casei rhamnosus soluble factors

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) is characterized by dense infiltrates of and defective apoptosis by mucosal cell populations. Some probiotics inhibit monocytes' expansion, although mechanisms remain unknown. Supernatants of Lactobacillus strains were investigated for inducing apoptosis of monocytes.

METHODS

Secreted factors produced by Lactobacillus strains were tested on human lymphocytes, monocytes and a human monocytic leukemia-cell line (THP-1). Cell death mechanisms were investigated by a variety of methods. Lipopolysaccharide (LPS)-induced proinflammatory cytokines (IL-1beta, IL-6, IL-8, TNF-alpha) and anti-inflammatory TGF-beta1 were determined.

RESULTS

Soluble factor(s) from Lactobacillus casei rhamnosus strain supernatants (LcrS) effectively induced apoptosis of immune cells. These were mainly soluble proteins (MW 5-30 kDa; LcrS(5-30)). For immune cells, but not human colonic epithelial carcinoma cells (HT-29), pretreatment with LcrS(5-30) significantly promoted apoptosis via a mitochondrial pathway. LcrS(5-30) suppressed pro-inflammatory cytokines and induced anti-inflammatory TGF-beta1.

CONCLUSIONS

Probiotic Lcr produced heat-stable molecules (MW range 5-30 kDa) that promoted immune cell apoptosis without affecting intestinal epithelial cells. LcrS(5-30) triggered apoptosis by a mitochondrial pathway, but not via TGF-beta signaling pathway. LcrS(5-30) also inhibited LPS-induced inflammatory cytokines by immune cells. Thus, LcrS(5-30) promotes apoptosis of immune cells, and suggests probiotics-based regimens for prevention of IBD.

Hypoxia. Regulation of NFkappaB signalling during inflammation: the role of hydroxylases

NFκB is a master regulator of innate immunity and inflammatory signalling. Microenvironmental hypoxia has long been identified as being coincident with chronic inflammation. The contribution of microenvironmental hypoxia to NFκB-induced inflammation has more recently been appreciated. Identification of the co-regulation of NFκB and hypoxia inducible factor (HIF) pathways by 2-oxo-glutarate-dependent hydroxylase family members has highlighted an intimate relationship between NFκB inflammatory signalling and HIF-mediated hypoxic signalling pathways. Adding another layer of complexity to our understanding of the role of NFκB inflammatory signalling by hypoxia is the recent recognition of the contribution of basal NFκB activity to HIF-1α transcription. This observation implicates an important and previously unappreciated role for NFκB in inflammatory disease where HIF-1α is activated. The present review will discuss recent literature pertaining to the regulation of NFκB inflammatory signalling by hypoxia and some of the inflammatory diseases where this may play an important role. Furthermore, we will discuss the potential for prolylhydroxylase inhibitors in inflammatory disease.

Molecular pathogenesis of inflammatory bowel disease: relevance for novel therapies

The immense load of microorganisms within the gastrointestinal tract is a great challenge for the mucosal immune system. Whereas the vast majority of commensal bacteria should be tolerated, pathogenic organisms have to be attacked. During inflammatory bowel disease, the balanced interaction between the mucosal flora and the intestinal immune system is disturbed. Various defective components of this complex interaction have been described, such as different susceptibility genes, impaired innate immune responses and environmental factors, suggesting that inflammatory bowel diseases are multifactorial diseases. Based on new insights into the pathogenesis of inflammatory bowel disease, various targets for future drugs have been identified and new substances are emerging. The following article will review the current understanding of inflammatory bowel disease pathogenesis in context with genetic risk factors, imbalanced innate and acquired immune responses, and altered barrier function. Clinical treatment of the diseases will be summarized and emerging therapies as well as individual management based on recent insights into pathogenesis will be discussed.

Inflammatory bowel disease following solid organ transplantation

Inflammatory bowel disease (IBD) is a T cell driven inflammatory condition of the gut. Following solid organ transplantation (SOT), de novo IBD has been reported despite anti-T cell therapy for the prevention of organ rejection. This paradox is illustrated with a case report, highlighting the difficult diagnostic criteria, the potential role of Damage or Pathogen Associated Molecular Pattern Molecules [DAMPs and PAMPs] that drives aspects of ongoing inflammation within the transplanted organ as well as the intestine, and the therapeutic strategies applied. Recurrent IBD is more common than de novo IBD following transplantation, with cumulative risks ten years after orthotopic liver transplantation of 70% and 30%, respectively. Furthermore, the annual incidence of de novo IBD following solid organ transplantation has been estimated to be 206 cases/100,000 or ten times the expected incidence of IBD in the general population (approximately 20 cases/100,000). The association of IBD with other autoimmune conditions such as primary sclerosing cholangitis and autoimmune hepatitis, both common indications for liver transplantation, may play a contributory role, particularly in view of the observation that IBD is more common following liver transplant than other solid organ transplants. Recurrent IBD following transplant appears to run a more aggressive course than de novo IBD, with a higher proportion requiring colectomy for medically refractory disease. Risk factors that have been associated with development of post-transplant IBD include acute CMV infection and the use of tacrolimus.

Apoptosis and Bax, Bcl-2, Mcl-1 expression in neutrophils of Crohn's disease patients

BACKGROUND

The etiology of Crohn's disease (CD) remains unknown, and the defective function of neutrophils appears to be associated with this pathology. Neutrophils undergo spontaneous apoptosis which, if not tightly regulated, can induce the development of chronic inflammatory disease. The Bcl-2 protein family is also involved in the regulation of neutrophil apoptosis.

METHODS

This study investigated the apoptosis and expression of some regulatory factors in CD patient and control polymorphonuclear neutrophils (PMN) in suspension and in adhesion on fibronectin, an extracellular matrix protein. These 2 conditions mimic circulating neutrophils before they are recruited at the intestinal levels, and their adhesion to tissue.

RESULTS

Apoptosis in CD patient PMN was delayed in suspension and accelerated in adhesion, which is the opposite of what happens in controls. Higher levels of Bax, Bcl-2, and Mcl-1 proteins were registered in freshly isolated CD patient PMN, in contrast to controls, in which Bcl-2 protein was undetectable. Among the studied pro- and antiapoptotic factors, Bax levels seem to be mainly related to the difference in apoptosis between PMN of CD patients and controls.

CONCLUSIONS

For the first time it has been demonstrated by direct experimental evidence that apoptosis in CD patient PMN is regulated differently from that of control PMN. Abnormal expression of regulating apoptosis proteins is shown in CD patient PMN. These data suggest that the defective functionality of neutrophils can be the early event responsible for the altered mucosal immune response in CD, and that neutrophil apoptosis may offer a new target for specific drugs and therapy tools.

The hydroxylase inhibitor dimethyloxalylglycine is protective in a murine model of colitis

BACKGROUND & AIMS

Prolyl and asparaginyl hydroxylases are key oxygen-sensing enzymes that confer hypoxic sensitivity to transcriptional regulatory pathways including the hypoxia inducible factor 1 (HIF-1) and nuclear factor-kappaB (NF-kappaB). Knockout of either HIF-1 or (IKKbeta-dependent) NF-kappaB pathways in intestinal epithelial cells promotes inflammatory disease in murine models of colitis. Both HIF-1 and NF-kappaB pathways are repressed by the action of hydroxylases through the hydroxylation of key regulatory molecules.

METHODS

In this study we have investigated the effects of the hydroxylase inhibitor dimethyloxalylglycine (DMOG) on Caco-2 intestinal epithelial cells in vitro and in a dextran sodium sulfate-induced model of murine colitis.

RESULTS

DMOG induces both HIF-1 and NF-kappaB activity in cultured intestinal epithelial cells, and is profoundly protective in dextran-sodium sulfate colitis in a manner that is at least in part reflected by the development of an anti-apoptotic phenotype in intestinal epithelial cells, which we propose reduces epithelial barrier dysfunction.

CONCLUSIONS

These data show that hydroxylase inhibitors such as DMOG represent a new strategy for the treatment of inflammatory bowel disease.

Biochemical aspects of inflammation

This review considers biochemical aspects of inflammation. The international literature until December 2006 has been analyzed, with the principal attention paid to the most dynamic problems: enzymology of inflammation, its regulation by hormones and signal transducers, and negative feedbacks, which underlie intensive current studies on pathogenesis, diagnostics, and therapy of inflammation. Such achievements as discoveries of defensins, toll-like receptors, interconnections of inflammation and iron metabolism, the roles of oxidative stress and antioxidant defense, lipoxins, inflammatory components of "non-inflammatory" diseases, and action mechanisms of effective drugs are discussed.

CD44v7 ligation downregulates the inflammatory immune response in Crohn's disease patients by apoptosis induction in mononuclear cells from the lamina propria

Deletion of exon CD44v7 abrogates experimental colitis by apoptosis induction in intestinal mononuclear cells. Here we show that CD44v7 expression was upregulated upon CD40 ligation in human mononuclear cells, and examined whether ligation of CD44v7 also affects activation and apoptosis in lamina propria mononuclear cells (LPMC) from Crohn's disease (CD) patients. Thirty five patients with chronic inflammatory bowel disease (IBD), fourteen controls and four patients with diverticulitis were evaluated. CD44v7 was upregulated predominantly in the inflamed mucosa of CD patients. Furthermore, incubation with an anti-CD44v7 antibody induced apoptosis in LPMC isolated from inflamed mucosa of CD patients, but not from non-inflamed mucosa, from patients with ulcerative colitis (UC) or from normal controls. CD40 ligation and simultaneous incubation with anti-CD44v7 significantly downregulated CD80 in dendritic cells, thus inhibiting a critical second signal for naive T-cell activation. The apoptotic signal was mediated via the intrinsic mitochondrial pathway with decreased Bcl-2 and increased 7A6 (a mitochondrial membrane protein) expression. It was Fas independent and required caspases-3 and -9 activation. The process is highly specific for macrophage activation via CD40. These findings point to a novel mechanism of apoptosis induction in CD patients mediated by CD44v7 ligation.

Parathyroid hormone-related protein (PTHrP) inhibits mitochondrial-dependent apoptosis through CK2

Over the past decade, parathyroid hormone-related protein (PTHrP) has been identified as a key survival factor for cells subjected to apoptotic stimuli. Its anti-apoptotic activity has been attributed to nuclear accumulation of the intact protein, or a synthetic peptide corresponding to its nuclear targeting sequence (NTS), which promotes rapid exit of nutrient deprived cells from the cell cycle. Intracellular PTHrP also inhibited apoptosis by blocking tumor necrosis factor alpha (TNFalpha)-induced apoptosis by blocking signaling from the "death receptor" and preventing damage to the mitochondrial membrane. In both cases, the anti-apoptotic activity was significantly reduced in the presence of a nuclear deficient form of PTHrP with a (88)K/E K/E.K/I(91) mutation in the NTS. The current work was undertaken to determine the mechanism by which nuclear PTHrP blocked mitochondrial-mediated apoptosis. Using sub-cellular fractionation and functional assays we showed that pre-treatment of HEK293 cells with exogenous NTS peptide before inducing apoptosis with TNFalpha was as effective as expression of the full-length protein in inhibiting apoptosis. Inhibition of apoptosis was associated with increased expression of protein kinase casein kinase 2 (CK2) and in sustained CK2 accumulation and activity in the nuclear fraction. In primary chondrogenic cells harvested from the limb buds of PTHrP(+/-) and PTHrP(-/-) embryonic mice, there was a dose-dependent decrease in CK2 expression and activity that correlated with increased susceptibility to apoptosis. Taken together the results indicate that nuclear accumulation of PTHrP effectively inhibits mitochondrial-mediated apoptosis through regulation of the expression, activity, and sub-cellular trafficking of CK2.