Tim Raine

Paneth cells as a site of origin for intestinal inflammation

The recognition of autophagy related 16-like 1 (ATG16L1) as a genetic risk factor has exposed the critical role of autophagy in Crohn’s disease. Homozygosity for the highly prevalent ATG16L1 risk allele, or murine hypomorphic (HM) activity, causes Paneth cell dysfunction. As Atg16l1HM mice do not develop spontaneous intestinal inflammation, the mechanism(s) by which ATG16L1 contributes to disease remains obscure. Deletion of the unfolded protein response (UPR) transcription factor X-box binding protein-1 (Xbp1) in intestinal epithelial cells, the human orthologue of which harbours rare inflammatory bowel disease risk variants, results in endoplasmic reticulum (ER) stress, Paneth cell impairment and spontaneous enteritis. Unresolved ER stress is a common feature of inflammatory bowel disease epithelium, and several genetic risk factors of Crohn’s disease affect Paneth cells. Here we show that impairment in either UPR (Xbp1ΔIEC) or autophagy function (Atg16l1ΔIEC or Atg7ΔIEC) in intestinal epithelial cells results in each other’s compensatory engagement, and severe spontaneous Crohn’s-disease-like transmural ileitis if both mechanisms are compromised. Xbp1ΔIEC mice show autophagosome formation in hypomorphic Paneth cells, which is linked to ER stress via protein kinase RNA-like endoplasmic reticulum kinase (PERK), elongation initiation factor 2α (eIF2α) and activating transcription factor 4 (ATF4). Ileitis is dependent on commensal microbiota and derives from increased intestinal epithelial cell death, inositol requiring enzyme 1α (IRE1α)-regulated NF-κB activation and tumour-necrosis factor signalling, which are synergistically increased when autophagy is deficient. ATG16L1 restrains IRE1α activity, and augmentation of autophagy in intestinal epithelial cells ameliorates ER stress-induced intestinal inflammation and eases NF-κB overactivation and intestinal epithelial cell death. ER stress, autophagy induction and spontaneous ileitis emerge from Paneth-cell-specific deletion of Xbp1. Genetically and environmentally controlled UPR function within Paneth cells may therefore set the threshold for the development of intestinal inflammation upon hypomorphic ATG16L1 function and implicate ileal Crohn’s disease as a specific disorder of Paneth cells.

Inhibition of autoimmune type 1 diabetes by gastrointestinal helminth infection

ABSTRACT Gastrointestinal nematode infections are prevalent worldwide and are potent inducers of T helper 2 responses with the capacity to modulate the immune response to heterologous antigens. Parasitic helminth infection has even been shown to modulate the immune response associated with autoimmune diseases. Nonobese diabetic (NOD) mice provide a model for studying human autoimmune diabetes; as in humans, the development of diabetes in NOD mice has been linked to the loss of self-tolerance to beta cell autoantigens. Previous studies with the NOD mouse have shown that helminth and bacterial infection appears to inhibit type 1 diabetes by disrupting the pathways leading to the Th1-mediated destruction of insulin-producing beta cells. The aim of our study was to examine whether infection with the gastrointestinal helminths Trichinella spiralis or Heligmosomoides polygyrus could inhibit the development of autoimmune diabetes in NOD mice and to analyze the mechanisms involved in protection and the role of Th2 responses. Protection from diabetes was afforded by helminth infection, appeared to inhibit autoimmune diabetes by disrupting pathways leading to the destruction of beta cells, and was mediated by seemingly independent mechanisms depending on the parasite but which may be to be related to the capacity of the host to mount a Th2 response.

Cutting Edge: Leukocyte Receptor Complex-Encoded Immunomodulatory Receptors Show Differing Specificity for Alternative HLA-B27 Structures

We studied recognition of the disease-associated HLA-B27 allele by immunomodulatory receptors encoded within the leukocyte receptor complex. HLA class I are ligands for members of the killer Ig receptor (KIR) and Ig-like transcript (ILT)/LIR/LILR families (the new LILR nomenclature is described at www. gene.ucl.ac.uk/nomenclature/genefamily/lilr.html). Members of these families bound HLA-B27 in both classical and β2 microglobulin-independent forms. Classical complexes bound ILT2, ILT4, and LIR6 transfectants but not ILT1, ILT3, or ILT5. A free H chain form of HLA-B27 bound ILT4 and LIR6. Both forms of HLA-B27 bound KIR3DL1 transfectants. HLA-B27 free H chain bound CD14+ cells in PBL from healthy controls, consistent with ILT4 expression on monocytes. Alternative recognition of different forms of HLA-B27 by KIR or ILT could influence their immunomodulatory function and may imply a role in inflammatory disease.

Cyclophosphamide-Induced Type-1 Diabetes in the NOD Mouse Is Associated with a Reduction of CD4+CD25+Foxp3+ Regulatory T Cells

Regulatory T cells (Tregs) have been implicated as key players in immune tolerance as well as suppression of antitumor responses. The chemotherapeutic alkylating agent cyclophosphamide (CY) is widely used in the treatment of tumors and some autoimmune conditions. Although previous data has demonstrated that Tregs may be preferentially affected by CY, its relevance in promoting autoimmune conditions has not been addressed. The nonobese diabetic mouse spontaneously develops type-1 diabetes (T1D). We demonstrate in this study that CY targets CD4+CD25+Foxp3+ Tregs in vivo. CD4+CD25+ T cells isolated from CY-treated mice display reduced suppressive activity in vitro and increased expression of apoptotic markers. Although Treg numbers rapidly recovered to pretreatment levels in the peripheral lymphoid tissues, Tregs failed to recover proportionally within pancreatic infiltrates. T1D progression was effectively prevented by adoptive transfer of a small number of islet Ag-specific CD4+CD25+ Tregs to CY-treated recipients. Prevention of T1D was associated with reduced T cell activation and higher Treg proportions in the pancreas. We conclude that acceleration of T1D by CY is associated with a reduction in CD4+CD25+Foxp3+ Tregs and can be prevented by transfer of CD4+CD25+ Tregs.

Third European Evidence-based Consensus on Diagnosis and Management of Ulcerative Colitis. Part 1: Definitions, Diagnosis, Extra-intestinal Manifestations, Pregnancy, Cancer Surveillance, Surgery, and Ileo-anal Pouch Disorders

aDepartment of Pharmacology and Therapeutics, University of Porto; MedInUP, Centre for Drug Discovery and Innovative Medicines; Centro Hospitalar São João, Porto, Portugal bIBD Unit, DIMEC, University of Bologna, Bologna, Italy cDepartment of Gastroenterology and Hepatology, Chaim Sheba Medical Center, Tel Hashomer, Israel dGastrointestinal Unit ASST Fatebenefratelli Sacco—University of Milan—Milan, Italy eIBD Unit Complesso Integrato Columbus, Gastroenterological and Endocrino-Metabolical Sciences Department, Fondazione Policlinico Universitario Gemelli Universita’ Cattolica del Sacro Cuore, Rome, Italy fDepartment of Gastroenterology, IBD Unit, University Hospital Santiago De Compostela (CHUS), A Coruña, Spain gDepartment of Gastroenterology, North Zealand University Hospital, Frederikssund, Denmark hFirst Department of Medicine, Semmelweis University, Budapest, Hungary iIBD Unit, St Mark’s Hospital, Middlesex, UK jDepartment of Gastroenterology, University Hospital of Ghent, Ghent, Belgium kInstitute of Pathology, Medical University of Graz, Graz, Austria lDepartment of Gastroenterology, Pennine Acute Hospitals NHS Trust; Institute of Inflammation and Repair, University of Manchester, Manchester, UK mUnit of General Surgery, Second University of Naples, Napoli, Italy nMaria Skłodowska-Curie Memorial Cancer Centre and Institute of Oncology, Department of Oncological Gastroenterology Warsaw; Medical Centre for Postgraduate Education, Department of Gastroenterology, Hepatology and Clinical Oncology, Warsaw, Poland oDepartment of Medicine, University of Cambridge, Cambridge, UK pImperial College London; Chelsea and Westminster Hospital, London, UK qDepartment of Pathobiology /NC22, Lerner Research Institute; Department of Gastroenterology, Hepatology and Nutrition/A3, Digestive Disease and Surgery Institute, Cleveland Clinic Foundation, Cleveland, OH, USA

The First European Evidence-based Consensus on Extra-intestinal Manifestations in Inflammatory Bowel Disease.

This is the first European Crohn’s and Colitis Organisation [ECCO] consensus guideline that addresses extra-intestinal manifestations [EIMs] in inflammatory bowel disease [IBD]. It has been drafted by 21 ECCO members from 13 European countries. Although this is the first ECCO consensus guideline that primarily addresses EIMs, it is partly derived from, updates, and replaces previous ECCO consensus advice on EIMs, contained within the consensus guidelines for Crohn’s disease1 [CD] and ulcerative colitis2 [UC]. The strategy to define consensus was similar to that previously described in other ECCO consensus guidelines [available at www.ecco-ibd.eu]. Briefly, topics were selected by the ECCO guidelines committee [GuiCom]. ECCO members were selected to form working groups. Provisional ECCO Statements and supporting text were written following a comprehensive literature review, then refined following two voting rounds which included national representative participation by ECCO’s 35 member countries. The level of evidence was graded according to the Oxford Centre for Evidence-based Medicine [www.cebm.net]. The ECCO Statements were finalised by the authors at a meeting in Vienna in October 2014 and represent consensus with agreement of at least 80% of participants. Complete consensus [100% agreement] was reached for most statements. The supporting text was then finalised under the direction of each working group leader [VA, SV, FC, MH] before being integrated by the two consensus leaders [MH, FC]. This consensus guideline is pictorially represented within the freely available ECCO e-Guide [http://www.e-guide.ecco-ibd.eu/]. Up to 50% of patients with inflammatory bowel disease [IBD] experience at least one extra-intestinal manifestation [EIM], which can present before IBD is diagnosed.34,5,6 EIMs adversely impact upon patients’ quality of life and some, such as primary sclerosing cholangitis [PSC] or venous thromboembolism [VTE], can be life-threatening. The probability of developing EIMs increases with disease duration and in patients who already have one EIM.7 …

ER stress transcription factor Xbp1 suppresses intestinal tumorigenesis and directs intestinal stem cells

X-box–binding protein 1 suppresses tumor formation in the gut by regulating Ire1α and Stat3-mediated regenerative responses in the epithelium as a consequence of ER stress.

ECCO Position Statement on the Use of Biosimilars for Inflammatory Bowel Disease—An Update

Biosimilars of infliximab were first approved by the European Medicine Agency in 2013,1 , 2 based on pre-clinical studies on biosimilarity and on clinical data coming from two randomised controlled trials conducted in rheumatoid arthritis [RA] and ankylosing spondylitis [AS].3 , 4 Initially the European Crohn’s Colitis Organisation [ECCO] raised some caution on the use of biosimilars.5 This cautious approach was also supported by several national inflammatory bowel disease [IBD] societies5–12 [Table 1]. An insufficient understanding of the characteristics and use of biosimilars became evident in a web survey among ECCO members in the same period.13 View this table: Table 1. Available society guidelines. Since biosimilars were introduced in the EU market in early 2015, more data from IBD patients14–19 have supported the biosimilarity of biosimilar infliximab CT-P13 and the reference product, with no significant differences in terms of efficacy or safety, in either naive or switched patients in cohort studies. Importantly, a study showed clear cross-reactivity between the infliximab originator and CT-P13.20 Recently, a large nationwide Norwegian randomised controlled trial [NOR-SWITCH] on patients with immune-mediated diseases [Crohn’s disease; ulcerative colitis; psoriasis; psoriatic arthritis; RA and AS] found no differences in terms of clinical response, maintenance of remission, or adverse events in patients receiving CT-P13 compared with those receiving originator infliximab.21 Consideration of these findings22 together with a better understanding of the process of biosimilar development and regulatory approval, have contributed to a change in the perception of IBD experts, who now prescribe biosimilars with significantly more confidence.23 A task-force including Governing Board representatives and one representative from pertinent ECCO Committees performed a literature search and made relevant statements to summarise their shared position. The proposed statements were then discussed, agreed and approved in a Consensus meeting. The licensing of any biosimilar medication …

Salmonella typhimurium infection halts development of type 1 diabetes in NOD mice

Infectious disease has been proposed as an environmental modifier of autoimmunity in both human populations and the NOD mouse. We found that infection of NOD mice with attenuated, but not killed, Salmonella typhimurium can reduce the incidence of type 1 diabetes (T1D), even if infection occurs after the development of a peri‐islet pancreatic infiltrate. Functional diabetogenic effector T cells are still present, as demonstrated by the initiation of diabetes in NOD‐scid recipients of transferred splenocytes. High levels of IFN‐γ are secreted by splenocytes of infected mice, but there is no evidence of involvement of IL‐10 in the protective effect of the infection. Finally, prolonged changes in cell subsets are observed in infected mice involving invariant Vα14Jα281 NKT and dendritic cells. These data reinforce the idea that prevention of T1D in the NOD mouse cannot be reduced to the simple Th1/Th2 paradigm and that different infections may involve different protective mechanisms.

Salmonella typhimurium Infection in Nonobese Diabetic Mice Generates Immunomodulatory Dendritic Cells Able to Prevent Type 1 Diabetes

Infection, commencing across a wide age range, with a live, attenuated strain of Salmonella typhimurium, will halt the development of type 1 diabetes in the NOD mouse. The protective mechanism appears to involve the regulation of autoreactive T cells in a manner associated with long lasting changes in the innate immune compartment of these mice. We show in this study that autoreactive T cell priming and trafficking are altered in mice that have been infected previously by S. typhimurium. These changes are associated with sustained alterations in patterns of chemokine expression. We find that small numbers of dendritic cells from mice that have been previously infected with, but cleared all trace of a S. typhimurium infection are able to prevent the development of diabetes in the highly synchronized and aggressive cyclophosphamide-induced model. The effects we observe on autoreactive T cell trafficking are recapitulated by the immunomodulatory dendritic cell transfers in the cyclophosphamide model.