Inhibition of NF-κB signaling in human dendritic cells by the enteropathogenic Escherichia coli effector protein NleE.

Intestinal dendritic cells (DCs) send processes between epithelial cells into the gut lumen to sample pathogens. Noninvasive enteropathogenic Escherichia coli (EPEC) colonize the gut using a type three secretion system (T3SS) to inject effector proteins into epithelial cells. We hypothesized that EPEC might also inject proteins into DC processes to dampen immune recognition. Using a T3SS-linked fluorescence resonance energy transfer-based system we show that EPEC injects effectors into in vitro grown human myeloid DCs. Injected cells emit a blue signal due to cleavage of the green fluorescence resonance energy transfer-based substrate CCF2/AM by ß-lactamase. When cultured with a mutant EPEC unable to translocate effector proteins, myeloid DCs show rapid activation of NF-κB, secrete large amounts of proinflammatory cytokines and increase expression of CD80, CD83, and CD86, whereas wild-type EPEC barely elicits cytokine production and shuts off nuclear translocation of NF-κB p65. By deleting effector protein genes, we identified NleE as being critical for this effect. Expression of NleE in HeLa cells completely prevented nuclear p65 accumulation in response to IL1-ß, and luciferase production in an NF-κB reporter cell line. DCs cocultured with wild-type EPEC or NleE-complemented strains were less potent at inducing MLR. EPEC was also able to inject effectors into DCs sending processes through model gut epithelium in a transwell system and into Peyer's patch myeloid DCs. Thus, EPEC translocate effectors into human DCs to dampen the inflammatory response elicited by its own pathogen-associated molecular patterns.

Guidelines for colorectal cancer screening and surveillance in moderate and high risk groups (update from 2002).

The British Society of Gastroenterology (BSG) and the Association of Coloproctology for Great Britain and Ireland (ACPGBI) commissioned this update of the 2002 guidance. The aim, as before, is to provide guidance on the appropriateness, method and frequency of screening for people at moderate and high risk from colorectal cancer. This guidance provides some new recommendations for those with inflammatory bowel disease and for those at moderate risk resulting from a family history of colorectal cancer. In other areas guidance is relatively unchanged, but the recent literature was reviewed and is included where appropriate.

Are we meeting the standards set for endoscopy? Results of a large-scale prospective survey of endoscopic retrograde cholangio-pancreatograph practice.

OBJECTIVE: To examine endoscopic retrograde cholangio-pancreatography (ERCP) services and training in the UK. DESIGN: Prospective multicentre survey. SETTING: Five regions of England. PARTICIPANTS: Hospitals with an ERCP unit. OUTCOME MEASURES: Adherence to published guidelines, technical success rates, complications and mortality. RESULTS: Organisation questionnaires were returned by 76 of 81 (94%) units. Personal questionnaires were returned by 190 of 213 (89%) ERCP endoscopists and 74 of 91 (81%) ERCP trainees, of whom 45 (61%) reported participation in <50 ERCPs per annum. In all, 66 of 81 (81%) units collected prospective data on 5264 ERCPs, over a mean period of 195 days. Oximetry was used by all units, blood pressure monitoring by 47 of 66 (71%) and ECG monitoring by 37 of 66 (56%) units; 1484 of 4521 (33%) patients were given >5 mg of midalozam. Prothrombin time was recorded in 4539 of 5264 (86%) procedures. Antibiotics were given in 1021 of 1412 (72%) cases, where indicated. Patients' American Society of Anesthesiology (ASA) scores were 3-5 in 670 of 5264 (12.7%) ERCPs, and 4932 of 5264 (94%) ERCPs were scheduled with therapeutic intent. In total, 140 of 182 (77%) trained endoscopists demonstrated a cannulation rate >/=80%. The recorded cannulation rate among senior trainees (with an experience of >200 ERCPs) was 222/338 (66%). Completion of intended treatment was done in 3707 of 5264 (70.4%) ERCPs; 268 of 5264 (5.1%) procedures resulted in a complication. Procedure-related mortality was 21/5264 (0.4%). Mortality correlated with ASA score. CONCLUSION: Most ERCPs in the UK are performed on low-risk patients with therapeutic intent. Complication rates compare favourably with those reported internationally. However, quality suffers because there are too many trainees in too many low-volume ERCP centres.

Activated STAT4 and a functional role for IL-12 in human Peyer's patches.

T cells in the Peyer's patches (PP) of the human ileum are exposed to a myriad of dietary and bacterial Ags from the gut lumen. Recall proliferative responses to common dietary Ags are readily demonstrable by PP T cells from healthy individuals, and the cytokine response is dominated by IFN-gamma. Consistent with Th1 skewing, PP cells spontaneously secrete IL-12p70, and IL-12p40 protein can be visualized underneath the PP dome epithelium. In this study, we have analyzed IL-12 signaling in PP and investigated whether IL-12 plays a functional role. CD3+ T lymphocytes isolated from PP and adjacent ileal mucosa spontaneously secrete IFN-gamma with negligible IL-4 or IL-5. RNA transcripts for IL-12Rbeta2, the signaling component of the IL-12R, are present in purified CD4+ and CD8+ T PP lymphocytes. Active STAT4, a transcription factor essential for IL-12-mediated Th1 differentiation, is readily detectable in biopsies from PP and ileal mucosa and STAT4-DNA binding activity is demonstrable by EMSA. Nuclear proteins from CD3+ T PP lymphocytes contain STAT4 and T-bet, a transcription factor selectively expressed in Th1 cells. Stimulation of freshly isolated PP cells with staphylococcal enterotoxin B dramatically enhanced the production of IFN-gamma, an effect which was largely inhibited by neutralizing anti-IL-12 Ab. These data show that IL-12 in human PP is likely to be responsible for the Th1-dominated cytokine response of the human mucosal immune system.

The tissue distribution of the mRNA of ghrelin and subtypes of its receptor, GHS-R, in humans.

Ghrelin is a novel growth hormone-releasing peptide, originally identified in the rat stomach as the endogenous ligand for the growth hormone secretagogue-receptor (GHS-R1a). Ghrelin is involved in the regulation of GH release, but it has recently been suggested that ghrelin may have other actions, including effects on appetite, carbohydrate metabolism, heart, kidney, pancreas, gonads, and cell proliferation. The distribution of ghrelin, its functional receptor (type 1a) and the unspliced, non-functional GHS-R type 1b mRNA expression was investigated in various human tissues using classical and real-time reverse transcription and polymerase chain reaction. GHS-R1a was predominantly expressed in the pituitary and at much lower levels in the thyroid gland, pancreas, spleen, myocardium and adrenal gland. In contrast, ghrelin was found in the stomach, other parts of the gut and, indeed, in all the tissues studied (adrenal gland, atrium, breast, buccal mucosa, esophagus, Fallopian tube, fat tissue, gall bladder, human lymphocytes, ileum, kidney, left colon, liver, lung, lymph node, muscle, muscle, myocardium, ovary, pancreas, pituitary, placenta, prostate, right colon, skin, spleen, testis, thyroid, and vein). GHS-R1b expression was also widespread in all tissues studied. The significance of the widespread tissue distribution of ghrelin remains to be determined. These data suggest that ghrelin might have widespread physiological effects via different, partly unidentified, subtypes of the GHS-R in endocrine and non-endocrine tissues.