Differential expression of the TRAIL/TRAIL-receptor system in patients with inflammatory bowel disease

Death receptor 5 is required for intestinal stem cell activity during intestinal epithelial renewal at homoeostasis

Intestinal epithelial renewal, which depends on the proliferation and differentiation of intestinal stem cells (ISCs), is essential for epithelial homoeostasis. Understanding the mechanism controlling ISC activity is important. We found that death receptor 5 (DR5) gene deletion (DR5-/-) mice had impaired epithelial absorption and barrier function, resulting in delayed weight gain, which might be related to the general reduction of differentiated epithelial cells. In DR5-/- mice, the expression of ISC marker genes, the number of Olfm4+ ISCs, and the number of Ki67+ and BrdU+ cells in crypt were reduced. Furthermore, DR5 deletion inhibited the expression of lineage differentiation genes driving ISC differentiation into enterocytes, goblet cells, enteroendocrine cells, and Paneth cells. Therefore, DR5 gene loss may inhibit the intestinal epithelial renewal by dampening ISC activity. The ability of crypts from DR5-/- mice to form organoids decreased, and selective DR5 activation by Bioymifi promoted organoid growth and the expression of ISC and intestinal epithelial cell marker genes. Silencing of endogenous DR5 ligand TRAIL in organoids down-regulated the expression of ISC and intestinal epithelial cell marker genes. So, DR5 expressed in intestinal crypts was involved in the regulation of ISC activity. DR5 deletion in vivo or activation in organoids inhibited or enhanced the activity of Wnt, Notch, and BMP signalling through regulating the production of Paneth cell-derived ISC niche factors. DR5 gene deletion caused apoptosis and DNA damage in transit amplifying cells by inhibiting ERK1/2 activity in intestinal crypts. Inhibition of ERK1/2 with PD0325901 dampened the ISC activity and epithelial regeneration. In organoids, when Bioymifi's effect in activating ERK1/2 activity was completely blocked by PD0325901, its role in stimulating ISC activity and promoting epithelial regeneration was also eliminated. In summary, DR5 in intestinal crypts is essential for ISC activity during epithelial renewal under homoeostasis.

Immunophenotypic Analysis of T Lymphocytes and Cytokine Production in Elderly Practicing Physical Activities and Its Relationship with Quality of Life and Depression

Aging is a complex process often associated with a chronic inflammatory profile that alters several biological functions, including the immune system and cognitive and physical capacity. The practice of physical activity is increasingly gaining popularity as a method of preventing infections, depression, and other disorders that affect the quality of life of the elderly. Thus, this work analyzes the profile of cytokines and molecular markers expressed in immune cells of elderly people who practice physical activities or not, evaluating their impacts on the immune system and quality of life. For this, 48 individuals were recruited, and peripheral blood samples were collected for hemogram analysis, cytokine determination, and immunophenotyping. Elderly people were separated into two groups: practitioners with low-intensity physical activity and non-practitioners. Quality of life was assessed using the Whoqol-Old instrument, and depression was assessed using the Beck II Depression Inventory. When comparing the scores of the Whoqol-Old and Beck questionnaires, we observed a significant negative correlation between these two factors. The perception of a higher quality of life was present in the elderly who exercised and was related to greater autonomy and sensory abilities, whereas the presence of depression was lower. In the hemogram, we observed higher basophil and segmented counts in the sedentary elderly, whereas lymphocytes and monocytes had lower counts. Elderly practitioners of physical activities had higher levels of IFN-γ, IL-4, and IL-10; increased expression of CD69, PD1, and TIM-3 in CD4+ T lymphocytes and increased CD14+CD80+ and CD14+CD86+ monocytes. Elderly people with an increased perception of quality of life had higher levels of IFN-γ, higher expression of CD14+CD80+CD86+, and decreased levels of TRAIL. An increase in TRAIL was observed in individuals with depression, in addition to an increased expression of CD14+CD86+. These results show a clear correlation between the quality of life, level of depression, physical activity, and immune system function. Although some cytokines with a typical proinflammatory profile (IFN-γ) were observed, the results point to a protective state with benefits reflected in the general well-being of the elderly who exercise.

MEFV and NLRP3 Inflammasome Expression Is Attributed to Immature Macrophages and Correlates with Serum Inflammatory Proteins in Crohn´s Disease Patients

Inflammasomes are intracellular protein complexes whose activation results in proinflammatory cytokines. Inflammasomes are implicated in Crohn´s disease (CD) pathogenesis, yet the contribution of inflammasomes in intestinal epithelial cells (IECs) versus lamina propria (LP) macrophages is poorly understood. Whether inflammasome expression in intestinal tissue reflects the serum inflammatory protein profile of patients is also not known. We aimed to determine the intestinal cell types where inflammasome expression is increased in CD and if they correlate with the serum protein profile. RT-PCR and NanoString nCounter technology were used to characterize inflammasome gene expression in CD patients and controls. The mucosa, LP and IEC cell fractions and FACS-sorted cells were analyzed. Proximity extension assay with a 92-protein panel was used to determine the serum inflammatory protein profile. Compositional analysis was used to correlate ileum inflammasome gene expression with intestinal mononuclear phagocyte populations. We show that NLRP3 and MEFV inflammasome sensors and downstream effector expression including IL-1β are increased in inflamed mucosa of IBD patients and correlate with disease activity. Inflammasome gene expression increased with the abundance of immature intestinal macrophages, and increased IL-1β released by CD LP cells correlated with immature macrophage frequency. Inflammasome gene expression was also increased in circulating monocytes, the precursors of immature intestinal macrophages. Finally, the serum inflammatory profile of CD patients correlates with ileal expression of genes related to NLRP3 and MEFV inflammasomes. Overall, we show that MEFV and NLRP3 inflammasome expression in CD intestine is attributed to the accumulation of immature macrophages and correlates with serum inflammatory proteins.

[Immunohistochemical analysis of a hypoxia-associated signature in melanomas with positive and negative sentinel lymph nodes : Hypoxia-associated signature of primary cutaneous melanomas]

Metabolic reprogramming mediated by hypoxia-inducible factors and its downstream targets plays a crucial role in many human malignancies. Excessive proliferation of tumor cells under hypoxic conditions leads to metabolic reprogramming and altered gene expression enabling tumors to adapt to their hypoxic environment. Here we analyzed the metabolic signatures of primary cutaneous melanomas with positive and negative sentinel node status in order to evaluate potential differences in their metabolic signature. We found a positive correlation of the expression of glucose transporter 1 (GLUT-1) with tumor thickness and ulceration in all melanomas with subgroup analyses as well as in the subgroup with a negative sentinel node. Furthermore, the expression of vascular endothelial growth factor (VEGF) was positively correlated with the presence of ulceration in melanomas with positive sentinel node.

The Role of E3 Ubiquitin Ligases and Deubiquitinases in Inflammatory Bowel Disease: Friend or Foe?

Inflammatory bowel disease (IBD), which include Crohn’s disease (CD) and ulcerative colitis (UC), exhibits a complex multifactorial pathogenesis involving genetic susceptibility, imbalance of gut microbiota, mucosal immune disorder and environmental factors. Recent studies reported associations between ubiquitination and deubiquitination and the occurrence and development of inflammatory bowel disease. Ubiquitination modification, one of the most important types of post-translational modifications, is a multi-step enzymatic process involved in the regulation of various physiological processes of cells, including cell cycle progression, cell differentiation, apoptosis, and innate and adaptive immune responses. Alterations in ubiquitination and deubiquitination can lead to various diseases, including IBD. Here, we review the role of E3 ubiquitin ligases and deubiquitinases (DUBs) and their mediated ubiquitination and deubiquitination modifications in the pathogenesis of IBD. We highlight the importance of this type of posttranslational modification in the development of inflammation, and provide guidance for the future development of targeted therapeutics in IBD.

Influence of TRAIL Deficiency on Th17 Cells and Colonic Microbiota in Experimental Colitis Mouse Model

BACKGROUND

The abnormalities of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) are implicated in various autoimmune disorders and tumors. This study investigated the influence of TRAIL deficiency on Th17 cells and colonic microbiota in experimental colitis mouse model.

METHODS

Mice were randomly divided into 4 groups: wild-type, TRAIL gene knock-out (TRAIL^-/-), wild-type colitis and TRAIL^-/- colitis groups. Colitis was induced by oral administration of 3.5% dextran sulfate sodium (DSS) for 7 consecutive days. Mice were given scores for disease severity both clinically and histopathologically. Th17 cells in peripheral blood and mesenteric lymph nodes (MLNs) were assessed using flow cytometry. The expression levels of Th17 cell markers IL-17A and ROR-γt were evaluated by quantitative real-time polymerase chain reaction. The colonic samples were also analyzed for microbiota profile by 16s-rDNA gene sequencing on variable V4 region.

RESULTS

Compared with wild-type counterparts, TRAIL^-/- mice developed more severe colitis after DSS treatment. Colitis TRAIL^-/- mice had increased proportion of Th17 cells and elevated mRNA expression levels of IL-17A and ROR-γt in peripheral blood and MLNs compared with colitis wild-type mice. In contrast to colitis wild-type mice, the composition of colonic microbiota was shifted in colitis TRAIL^-/- mice, and was characterized by increased alpha diversity, increased TM7, deferribacteres and tenericutes, and decreased proteobacteria at the phylum level.

CONCLUSIONS

These findings suggested that TRAIL deficiency not only aggravated DSS-induced colitis, but also led to enhanced Th17 cell response and altered colonic microbiota composition.

Role of myeloid-derived suppressor cells in the promotion and immunotherapy of colitis-associated cancer

Colitis-associated cancer (CAC) is a specific type of colorectal cancer that develops from inflammatory bowel disease (IBD). Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells that are essential for the pathological processes of inflammation and cancer. Accumulating evidence indicates that MDSCs play different but vital roles during IBD and CAC development and impede CAC immunotherapy. New insights into the regulatory network of MDSCs in the CAC pathogenesis are opening new avenues for developing strategies to enhance the effectiveness of CAC treatment. In this review, we explore the role of MDSCs in chronic inflammation, dysplasia and CAC and summarize the potential CAC therapeutic strategies based on MDSC blockade.

Inflammatory bowel disease-associated ubiquitin ligase RNF183 promotes lysosomal degradation of DR5 and TRAIL-induced caspase activation

RNF183 is a ubiquitin ligase containing RING-finger and transmembrane domains, and its expression levels are increased in patients with inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, and in 2,4,6-trinitrobenzene sulfonic acid-induced colitis mice. Here, we further demonstrate that RNF183 was induced to a greater degree in the dextran sulfate sodium (DSS)-treated IBD model at a very early stage than were inflammatory cytokines. In addition, fluorescence-activated cell sorting and polymerase chain reaction analysis revealed that RNF183 was specifically expressed in epithelial cells of DSS-treated mice, which suggested that increased levels of RNF183 do not result from the accumulation of immune cells. Furthermore, we identified death receptor 5 (DR5), a member of tumour necrosis factor (TNF)-receptor superfamily, as a substrate of RNF183. RNF183 mediated K63-linked ubiquitination and lysosomal degradation of DR5. DR5 promotes TNF-related apoptosis inducing ligand (TRAIL)-induced apoptosis signal through interaction with caspase-8. Inhibition of RNF183 expression was found to suppress TRAIL-induced activation of caspase-8 and caspase-3. Thus, RNF183 promoted not only DR5 transport to lysosomes but also TRAIL-induced caspase activation and apoptosis. Together, our results provide new insights into potential roles of RNF183 in DR5-mediated caspase activation in IBD pathogenesis.

Expression of tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL) in minor salivary glands and saliva

OBJECTIVE

The aim of this study was to characterize the baseline expression of tumor necrosis factor (tnf)-related apoptosis inducing ligand (TRAIL) in minor salivary glands, gingiva and saliva from healthy individuals.

DESIGN

Minor salivary gland and gingival tissues were used in the study for immunohistochemical staining. An enzyme-linked immunosorbent assay was used to measure the levels of TRAIL in unstimulated saliva and parotid saliva collected from non-smoking individuals. The salivary levels of TRAIL are presented as secretory output.

RESULTS

Parotid saliva showed higher secretory output (327.8 ± 41.6 pg/min) for TRAIL compared to unstimulated saliva (212.3 ± 32.1 pg/min; p =0.041). For unstimulated saliva, the young female subjects had the lowest secretory output (119 ± 17.2 pg/min) compared to elderly females (275 ± 62.18 pg/min; p =0.046) and young males (294.4 ± 50.2 pg/min; p =0.021). The ductal cells of salivary glands exhibited the strongest positivity for TRAIL, whereas mucous cells showed no staining for TRAIL. Serous cells displayed an intermediate staining. Gingival tissues showed gradually decreasing staining towards the basal layer.

CONCLUSIONS

The current study shows that TRAIL is not only expressed by immune cells, but also by the epithelial cells of salivary glands. Saliva contains high concentrations of soluble TRAIL that suggest roles of this protein in the apoptosis of tumor cells.

DR4-Ser424 O-GlcNAcylation Promotes Sensitization of TRAIL-Tolerant Persisters and TRAIL-Resistant Cancer Cells to Death

TNF-related apoptosis-inducing ligand (TRAIL) resistance, including nongenetically acquired tolerance in cancer persister cells, is a major obstacle to translating TRAIL therapy into patients with cancer. However, the underlying mechanisms remain to be elucidated. Here, we show that DR4/TRAIL-R1 is O-GlcNAcylated at Ser424 in its death domain to mediate both apoptosis and necrosis upon TRAIL ligation. We found that DR4-Ser424 mutations, identified from our cell-based functional screen using a cancer patient-derived cDNA expression library and from The Cancer Genome Atlas, caused TRAIL resistance in various human cancer cell lines. Using O-GlcNAc transferase knockdown cells, DR4-preferred versus DR5-preferred cancer cells, and a DR5-neutralizing antibody, we evaluated the essential role of DR4-specific O-GlcNAc modification in TRAIL cytotoxicity. In contrast to DR4, DR5 was not O-GlcNAcylated by TRAIL treatment, discriminating DR4 from DR5-mediated signaling. Apart from genetic changes in DR4-Ser424, we further classified various cancer cell lines originated from stomach, colon, lung, and glioblastoma according to their sensitivity to and receptor preference upon TRAIL death signaling and generated TRAIL-tolerant persister-derived DLD-1^PER cells. Among these, we discovered that DR4 was not modified by O-GlcNAc in most of the TRAIL-resistant cancer cells and DLD-1^PER cells. Interestingly, promoting DR4 O-GlcNAcylation intentionally using 2-deoxy-d-glucose or a high concentration of glucose sensitized those resistant cancer cells to TRAIL. The O-GlcNAcylation-defective DR4 failed to form DISC/necrosome and could not translocate to aggregated platforms for receptor clustering. Our findings demonstrate that DR4 O-GlcNAcylation is crucial for TRAIL death signaling, providing new opportunities for TRAIL therapy overcoming TRAIL resistance in cancers. SIGNIFICANCE: This study reports that a novel posttranslational modification by O-GlcNAcylation of one of the two human TRAIL receptors with a death domain, TRAIL-R1 (DR4), plays a crucial role in enabling both apoptotic and necroptotic cell death induction by TRAIL.

The TNF Family of Ligands and Receptors: Communication Modules in the Immune System and Beyond

The tumor necrosis factor (TNF) and TNF receptor (TNFR) superfamilies (TNFSF/TNFRSF) include 19 ligands and 29 receptors that play important roles in the modulation of cellular functions. The communication pathways mediated by TNFSF/TNFRSF are essential for numerous developmental, homeostatic, and stimulus-responsive processes in vivo. TNFSF/TNFRSF members regulate cellular differentiation, survival, and programmed death, but their most critical functions pertain to the immune system. Both innate and adaptive immune cells are controlled by TNFSF/TNFRSF members in a manner that is crucial for the coordination of various mechanisms driving either co-stimulation or co-inhibition of the immune response. Dysregulation of these same signaling pathways has been implicated in inflammatory and autoimmune diseases, highlighting the importance of their tight regulation. Investigation of the control of TNFSF/TNFRSF activities has led to the development of therapeutics with the potential to reduce chronic inflammation or promote anti-tumor immunity. The study of TNFSF/TNFRSF proteins has exploded over the last 30 yr, but there remains a need to better understand the fundamental mechanisms underlying the molecular pathways they mediate to design more effective anti-inflammatory and anti-cancer therapies.

Regulation of antiapoptotic and cytoprotective pathways in colonic epithelial cells in ulcerative colitis

Ulcerative colitis is an inflammatory bowel disease involving the colon resulting in bloody diarrhea and increased risk of colorectal cancer in certain patient subgroups. Increased apoptosis in the epithelial cell layer causes increased permeability, especially during flares; this leads to translocation of luminal pathogens resulting in a continued inflammatory drive. The present work investigates how epithelial apoptosis is regulated in ulcerative colitis. The main results are that Fas mediated apoptosis is inhibited during flares of ulcerative colitis, probably by an upregulation of cellular inhibitor of apoptosis protein 2 (cIAP2) and cellular FLICE-like inhibitory protein. cIAP2 is upregulated in regenerative epithelial cells both in ulcerative colitis and in experimental intestinal wounds. Inhibition of cIAP2 decreases wound healing in vitro possibly through inhibition of migration. Altogether, it is shown that epithelial cells in ulcerative colitis responds to the hostile microenvironment by activation of cytoprotective pathways that tend to counteract the cytotoxic effects of inflammation. However, the present studies also show that epithelial cells produce increased amounts of reactive oxygen species during stimulation with tumor necrosis factor-α and interferon-γ resulting in DNA instability. The combined effect of increased DNA-instability and decreased apoptosis responses could lead to neoplasia.

Cell death at the intestinal epithelial front line

The intestinal epithelium represents the largest epithelial surface in our body. This single-cell-layer epithelium mediates important functions in the absorption of nutrients and in the maintenance of barrier function, preventing luminal microorganisms from invading the body. Due to its constant regeneration the intestinal epithelium is a tissue not only with very high proliferation rates but also with very prominent physiological and pathophysiological cell death induction. The normal physiological differentiation and maturation of intestinal epithelial cells leads to their shedding and apoptotic cell death within a few days, without disturbing the epithelial barrier integrity. In contrast excessive intestinal epithelial cell death induced by irradiation, drugs and inflammation severely impairs the vital functions of this tissue. In this review we discuss cell death processes in the intestinal epithelium in health and disease, with special emphasis on cell death triggered by the tumour necrosis factor receptor family.

Tumor necrosis factor-related apoptosis-inducing ligand induces the expression of proinflammatory cytokines in macrophages and re-educates tumor-associated macrophages to an antitumor phenotype

This study reveals that tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) induces expression of IL-1β, IL-6, and tumor necrosis factor α in macrophages, especially in tumor-associated macrophages (TAMs). TRAIL re-educates TAMs to an M1-like phenotype and induces their cytotoxicity to tumor cells. This study provides new evidence for TRAIL in immune regulation of macrophages and sheds light on TRAIL-based antitumor therapy in human patients.

Tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) is a promising candidate for cancer therapy, because it can induce apoptosis in various tumor cells but not in most normal cells. Although it is well known that TRAIL and its receptors are expressed in many types of normal cells, including immune cells, their immunological effects and regulatory mechanisms are still obscure. In the present study, we demonstrated that TRAIL affected the activity of NF-κB (nuclear factor-κB) and the expression of its downstream proinflammatory cytokines IL-1β (interleukin-1β), IL-6, and tumor necrosis factor α in macrophages. TRAIL also induced microRNA-146a (miR-146a) expression in an NF-κB–dependent manner. As a result, miR-146a was involved as a negative-feedback regulator in the down-regulation of proinflammatory cytokine expression. In addition, the suppression of histone deacetylase (HDAC) activities by trichostatin A improved miR-146a expression due to the up-regulation of the DNA-binding activity of NF-κB at the miR-146a promoter in TRAIL-induced macrophages, suggesting that histone acetylation was involved in the suppression of miR-146a expression. Further investigation revealed that the HDAC subtype HDAC1 directly regulated the expression of miR-146a in TRAIL-stimulated macrophages. Finally, the TRAIL-sensitive human non small cell lung carcinoma cell line NCI-H460 was used to elucidate the physiological significance of TRAIL with respect to tumor-associated macrophages (TAMs). We demonstrated that TRAIL re-educated TAMs to an M1-like phenotype and induced cytotoxic effects in the tumor cells. These data provide new evidence for TRAIL in the immune regulation of macrophages and may shed light on TRAIL-based antitumor therapy in human patients.

The integrated disease network

The growing body of transcriptomic, proteomic, metabolomic and genomic data generated from disease states provides a great opportunity to improve our current understanding of the molecular mechanisms driving diseases and shared between diseases. The use of both clinical and molecular phenotypes will lead to better disease understanding and classification. In this study, we set out to gain novel insights into diseases and their relationships by utilising knowledge gained from system-level molecular data. We integrated different types of biological data including genome-wide association studies data, disease-chemical associations, biological pathways and Gene Ontology annotations into an Integrated Disease Network (IDN), a heterogeneous network where nodes are bio-entities and edges between nodes represent their associations. We also introduced a novel disease similarity measure to infer disease-disease associations from the IDN. Our predicted associations were systemically evaluated against the Medical Subject Heading classification and a statistical measure of disease co-occurrence in PubMed. The strong correlation between our predictions and co-occurrence associations indicated the ability of our approach to recover known disease associations. Furthermore, we presented a case study of Crohn's disease. We demonstrated that our approach not only identified well-established connections between Crohn's disease and other diseases, but also revealed new, interesting connections consistent with emerging literature. Our approach also enabled ready access to the knowledge supporting these new connections, making this a powerful approach for exploring connections between diseases.

Tumour necrosis factor superfamily members in the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a group of inflammatory conditions of the gastrointestinal tract of unclear aetiology of which two major forms are Crohn's disease (CD) and ulcerative colitis (UC). CD and UC are immunologically distinct, although they both result from hyperactivation of proinflammatory pathways in intestines and disruption of intestinal epithelial barrier. Members of the tumour necrosis factor superfamily (TNFSF) are molecules of broad spectrum of activity, including direct disruption of intestinal epithelial barrier integrity and costimulation of proinflammatory functions of lymphocytes. Tumour necrosis factor (TNF) has a well-established pathological role in IBD which also serves as a target in IBD treatment. In this review we discuss the role of TNF and other TNFSF members, notably, TL1A, FasL, LIGHT, TRAIL, and TWEAK, in the pathogenesis of IBD.

Interaction of dietary fatty acids with tumour necrosis factor family cytokines during colon inflammation and cancer

Intestinal homeostasis is precisely regulated by a number of endogenous regulatory molecules but significantly influenced by dietary compounds. Malfunction of this system may result in chronic inflammation and cancer. Dietary essential n-3 polyunsaturated fatty acids (PUFAs) and short-chain fatty acid butyrate produced from fibre display anti-inflammatory and anticancer activities. Both compounds were shown to modulate the production and activities of TNF family cytokines. Cytokines from the TNF family (TNF- α, TRAIL, and FasL) have potent inflammatory activities and can also regulate apoptosis, which plays an important role in cancer development. The results of our own research showed enhancement of apoptosis in colon cancer cells by a combination of either docosahexaenoic acid (DHA) or butyrate with TNF family cytokines, especially by promotion of the mitochondrial apoptotic pathway and modulation of NF κ B activity. This review is focused mainly on the interaction of dietary PUFAs and butyrate with these cytokines during colon inflammation and cancer development. We summarised recent knowledge about the cellular and molecular mechanisms involved in such effects and outcomes for intestinal cell behaviour and pathologies. Finally, the possible application for the prevention and therapy of colon inflammation and cancer is also outlined.

TRAIL receptor deficiency sensitizes mice to dextran sodium sulphate-induced colitis and colitis-associated carcinogenesis

Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and its receptor (TRAIL-R) play important roles in immune regulation and cancer cell death. Although TRAIL has been shown to induce chemokine release in various tumour cells, the function of TRAIL-R in the development of colitis and colitis-associated carcinogenesis has not been explored. In this study, we found that TRAIL-R-deficient mice exhibited a higher incidence of colitis and colitis-associated cancer than that of wild-type (WT) mice, and TRAIL-R expression was down-regulated in WT mice that were fed dextran sulphate sodium. Chemokines, including CCL2 and CXCL1, were highly expressed in the serum and inflammatory colon tissues of TRAIL-R(-/-) mice compared with WT mice, and TRAIL-R(-/-) mice showed a marked infiltration of immune cells during colitis. Hyperactivation of Janus kinase and nuclear factor-κB in colon epithelial cells was also observed, which correlated with the severity of colonic inflammation in TRAIL-R(-/-) mice. These data suggest that TRAIL-R plays a protective role in chemical-induced colon injury and negatively regulates mucosal immune responses.

Levels of TNF-related apoptosis-inducing ligand (TRAIL) show a long-term stability in the breast milk of mothers of preterm infants

BACKGROUND

The immune modulator TNF-related apoptosis-inducing ligand (TRAIL) has been found at extremely high levels in human milk of women with normal gestation at day 5 after delivery.

OBJECTIVE

To investigate the presence and the levels of soluble TRAIL in human milk of women with preterm delivery at different time points post-partum (32, 34, and 36 weeks from conception).

METHODS

The levels of soluble TRAIL were analyzed by ELISA in the breast milk of a group of 25 women with preterm delivery at different gestational ages.

RESULTS

Soluble TRAIL was present at high levels in human milk since early post-conceptional ages (32 weeks). No significant differences in TRAIL levels were noticed with respect to different gestational ages, or with respect to time of collection when comparing, in a selected group of patients, samples obtained between 15 and 26 days with those obtained 27 and 40 days after birth.

CONCLUSION

Due to the key immunoregulatory role of human soluble TRAIL, the presence of high levels of TRAIL in the milk of women with preterm delivery and its maintenance at high levels up to 72 days after birth support the importance of breastfeeding the preterm newborn.

Human colostrum and breast milk contain high levels of TNF-related apoptosis-inducing ligand (TRAIL)

BACKGROUND

TNF-related apoptosis inducing ligand (TRAIL) is a pleiotropic cytokine, which plays a key role in the immune system as well as in controlling the balance of apoptosis and proliferation in various organs and tissues.

OBJECTIVE

To investigate the presence and levels of soluble TRAIL in human colostrum and milk.

METHODS

The levels of soluble human TRAIL were measured in human colostrum (day 2 after delivery) and breast milk (day 5 after delivery). The presence of TRAIL was also measured in infant formula.

RESULTS

Levels of soluble TRAIL in the colostrum and mature human milk were, respectively, at least 400 and 100 fold higher than those detected in human serum. No TRAIL was detected in formula.

CONCLUSION

Human soluble TRAIL is present at extremely high levels in human colostrum and human milk and might have a significant role in mediating the anti-cancer activity of human milk.

Mucosal healing in ulcerative colitis: pathophysiology and pharmacology

Ulcerative colitis (UC) is a colonic inflammatory condition with a substantial impact on the quality of life of affected persons. The disease carries a cumulative risk of need of colectomy of 20-30% and an estimated cumulative risk of colorectal cancer of 18% after 30 years of disease duration. With the introduction of the tumor necrosis factor-alpha inhibitors for the treatment of UC, it has become increasingly evident that the disease course is influenced by whether or not the patient achieves mucosal healing. Thus, patients with mucosal healing have fewer flare-ups, a decreased risk of colectomy, and a lower probability of developing colorectal cancer. Understanding the mechanisms of mucosal wound formation and wound healing in UC, and how they are affected therapeutically is therefore of importance for obtaining efficient treatment strategies holding the potential of changing the disease course of UC. This review is focused on the pathophysiological mechanism of mucosal wound formation in UC as well as the known mechanisms of intestinal wound healing. Regarding the latter topic, pathways of both wound healing intrinsic to epithelial cells and the wound-healing mechanisms involving interaction between epithelial cells and other cells of the mucosa are discussed. The biochemistry of wound healing in UC provides the basis for the subsequent description of how these pathways are affected by the current medications, and what can be learnt on how to design future treatment regimens for UC based on targeting mucosal healing.

Protective pathways against colitis mediated by appendicitis and appendectomy

Appendicitis followed by appendectomy (AA) at a young age protects against inflammatory bowel disease (IBD). Using a novel murine appendicitis model, we showed that AA protected against subsequent experimental colitis. To delineate genes/pathways involved in this protection, AA was performed and samples harvested from the most distal colon. RNA was extracted from four individual colonic samples per group (AA group and double-laparotomy control group) and each sample microarray analysed followed by gene-set enrichment analysis (GSEA). The gene-expression study was validated by quantitative reverse transcription-polymerase chain reaction (RT-PCR) of 14 selected genes across the immunological spectrum. Distal colonic expression of 266 gene-sets was up-regulated significantly in AA group samples (false discovery rates < 1%; P-value < 0·001). Time-course RT-PCR experiments involving the 14 genes displayed down-regulation over 28 days. The IBD-associated genes tnfsf10, SLC22A5, C3, ccr5, irgm, ptger4 and ccl20 were modulated in AA mice 3 days after surgery. Many key immunological and cellular function-associated gene-sets involved in the protective effect of AA in experimental colitis were identified. The down-regulation of 14 selected genes over 28 days after surgery indicates activation, repression or de-repression of these genes leading to downstream AA-conferred anti-colitis protection. Further analysis of these genes, profiles and biological pathways may assist in developing better therapeutic strategies in the management of intractable IBD.