sodium-dodecyl-sulfate and Colitis

Chronic inflammation is often associated with the development of tissue fibrosis, but how mesenchymal cell responses dictate pathological fibrosis versus resolution and healing remains unclear. Defining stromal heterogeneity and identifying molecular circuits driving extracellular matrix deposition and remodeling stands to illuminate the relationship between inflammation, fibrosis, and healing. We performed single-cell RNA-sequencing of colon-derived stromal cells and identified distinct classes of fibroblasts with gene signatures that are differentially regulated by chronic inflammation, including IL-11-producing inflammatory fibroblasts. We further identify a transcriptional program associated with trans-differentiation of mucosa-associated fibroblasts and define a functional gene signature associated with matrix deposition and remodeling in the inflamed colon. Our analysis supports a critical role for the metalloprotease Adamdec1 at the interface between tissue remodeling and healing during colitis, demonstrating its requirement for colon epithelial integrity. These findings provide mechanistic insight into how inflammation perturbs stromal cell behaviors to drive fibroblastic responses controlling mucosal matrix remodeling and healing.

Topics: ADAM Proteins; Animals; Cell Differentiation; Colitis; Colon; Extracellular Matrix; Fibroblasts; Fibrosis; Gene Expression Regulation; Humans; Inflammation; Interleukin-11; Intestinal Mucosa; Male; Mesenchymal Stem Cells; Mice; Mice, Inbred C57BL; Sequence Analysis, RNA; Single-Cell Analysis; Sodium Dodecyl Sulfate; Transcription, Genetic; Transcriptome; Wound Healing

Phenolic compounds (PCs) present in foods are associated with a decreased risk of developing inflammatory diseases. The aim of this study was to extract and characterize PCs from craft beer powder and evaluate their potential benefits in an experimental model of inflammatory bowel disease (IBD). PCs were extracted and quantified from pure beer samples. BALB/c mice received either the beer phenolic extract (BPE) or beer powder fortified with phenolic extract (BPFPE) of PCs daily for 20 days by gavage. Colon samples were collected for histopathological and immunohistochemical analyses. Dextran sodium sulfate (DSS)-induced mice lost more weight, had reduced colon length, and developed more inflammatory changes compared with DSS-induced mice treated with either BPE or BPFPE. In addition, in DSS-induced mice, the densities of CD4- and CD11b-positive cells, apoptotic rates, and activation of NF-κB and p-ERK1/2 MAPK intracellular signaling pathways were higher in those treated with BPE and BPFPE than in those not treated. Pretreatment with the phenolic extract and BPFPE remarkably attenuated DSS-induced colitis. The protective effect of PCs supports further investigation and development of therapies for human IBD.

Topics: Animals; Beer; Colitis; Male; Mice; Mice, Inbred BALB C; Powders; Sodium Dodecyl Sulfate

Dynamic regulation of intestinal cell differentiation is crucial for both homeostasis and the response to injury or inflammation. Sprouty2, an intracellular signaling regulator, controls pathways including PI3K and MAPKs that are implicated in differentiation and are dysregulated in inflammatory bowel disease. Here, we ask whether Sprouty2 controls secretory cell differentiation and the response to colitis. We report that colonic epithelial Sprouty2 deletion leads to expanded tuft and goblet cell populations. Sprouty2 loss induces PI3K/Akt signaling, leading to GSK3β inhibition and epithelial interleukin (IL)-33 expression. In vivo, this results in increased stromal IL-13+ cells. IL-13 in turn induces tuft and goblet cell expansion in vitro and in vivo. Sprouty2 is downregulated by acute inflammation; this appears to be a protective response, as VillinCre;Sprouty2

Topics: Animals; Cell Count; Cell Differentiation; Cell Proliferation; Child; Colitis; Colon; Female; Gene Expression Regulation; Glycogen Synthase Kinase 3 beta; Goblet Cells; Homeostasis; HT29 Cells; Humans; Interleukin-33; Intestinal Mucosa; Male; Membrane Proteins; Mice; Mice, Inbred C57BL; Mice, Knockout; Microfilament Proteins; Phosphatidylinositol 3-Kinases; Protein Serine-Threonine Kinases; Proto-Oncogene Proteins c-akt; Signal Transduction; Sodium Dodecyl Sulfate

Stringent regulation of the transcription factor NF-κB signaling is essential for the activation of host immune responses and maintaining homeostasis, yet the molecular mechanisms involved in its tight regulation are not completely understood. In this study, we report that IKK-interacting protein (IKIP) negatively regulates NF-κB activation. IKIP interacted with IKKα/β to block its association with NEMO, thereby inhibiting the phosphorylation of IKKα/β and the activation of NF-κB. Upon LPS, TNF-α, and IL-1β stimulation, IKIP-deficient macrophages exhibited more and prolonged IKKα/β phosphorylation, IκB, and p65 phosphorylation and production of NF-κB-responsive genes. Moreover, IKIP-deficient mice were more susceptible to LPS-induced septic shock and dextran sodium sulfate-induced colitis. Our study identifies a previously unrecognized role for IKIP in the negative regulation of NF-κB activation by inhibition of IKKα/β phosphorylation through the disruption of IKK complex formation.

Topics: Animals; Colitis; Disease Models, Animal; Gene Expression Regulation; HEK293 Cells; Humans; I-kappa B Kinase; Inflammation; Interleukin-1beta; Lipopolysaccharides; Male; Mice; Mice, Inbred C57BL; Mice, Mutant Strains; NF-kappa B; Peptide Fragments; Phosphorylation; Protein Binding; Sodium Dodecyl Sulfate; Tumor Necrosis Factor-alpha

Astilbin is a potential agent for autoimmune and inflammatory diseases and has a protective effect in mice with DSS-induced colitis. NK1.1

Topics: Animals; Anti-Inflammatory Agents; Colitis; Extracellular Signal-Regulated MAP Kinases; Female; Flavonols; Humans; Injections, Intraperitoneal; Interleukin-10; Mice; Mice, Inbred C57BL; NK Cell Lectin-Like Receptor Subfamily K; Phosphatidylinositol 3-Kinases; Signal Transduction; Sodium Dodecyl Sulfate; STAT3 Transcription Factor; T-Lymphocytes, Regulatory; Transforming Growth Factor beta1

Mesenchymal stem cells (MSCs) have shown great promise in inflammatory bowel disease (IBD) treatment, owing to their immunosuppressive capabilities, but their therapeutic effectiveness is sometimes thwarted by their low efficiency in entering the inflamed colon and variable immunomodulatory ability in vivo. Here, we demonstrated a new methodology to manipulate MSCs to express CX3C chemokine receptor 1 (CX3CR1) and interleukin-25 (IL-25) to promote their delivery to the inflamed colon and enhance their immunosuppressive capability. Compared to MSCs without treatment, MSCs infected with a lentivirus (LV) encoding CX3CR1 and IL-25 (CX3CR1&IL-25-LV-MSCs) exhibited enhanced targeting to the inflamed colon and could further move into extravascular space of the colon tissues via trans-endothelial migration in dextran sodium sulfate (DSS)-challenged mice after MSC intravenous injection. The administration of the CX3CR1&IL-25-LV-MSCs achieved a better therapeutic effect than that of the untreated MSCs, as indicated by pathological indices and inflammatory markers. Antibody-blocking studies indicated that the enhanced therapeutic effects of dual-functionalized MSCs were dependent on CX3CR1 and IL-25 function. Overall, this strategy, which is based on enhancing the homing and immunosuppressive abilities of MSCs, represents a promising therapeutic approach that may be valuable in IBD therapy.

Topics: Animals; Colitis; CX3C Chemokine Receptor 1; Disease Models, Animal; Female; Interleukins; Lentivirus; Mesenchymal Stem Cell Transplantation; Mesenchymal Stem Cells; Mice; Rats; Sodium Dodecyl Sulfate; Treatment Outcome

Loss-of-function variants of protein tyrosine phosphatase non-receptor type 2 (PTPN2) enhance risk of inflammatory bowel disease and rheumatoid arthritis; however, whether the association between PTPN2 and autoimmune arthritis depends on gut inflammation is unknown. Here we demonstrate that induction of subclinical intestinal inflammation exacerbates development of autoimmune arthritis in SKG mice. Ptpn2-haploinsufficient SKG mice - modeling human carriers of disease-associated variants of PTPN2 - displayed enhanced colitis-induced arthritis and joint accumulation of Tregs expressing RAR-related orphan receptor γT (RORγt) - a gut-enriched Treg subset that can undergo conversion into FoxP3-IL-17+ arthritogenic exTregs. SKG colonic Tregs underwent higher conversion into arthritogenic exTregs when compared with peripheral Tregs, which was exacerbated by haploinsufficiency of Ptpn2. Ptpn2 haploinsufficiency led to selective joint accumulation of RORγt-expressing Tregs expressing the colonic marker G protein-coupled receptor 15 (GPR15) in arthritic mice and selectively enhanced conversion of GPR15+ Tregs into exTregs in vitro and in vivo. Inducible Treg-specific haploinsufficiency of Ptpn2 enhanced colitis-induced SKG arthritis and led to specific joint accumulation of GPR15+ exTregs. Our data validate the SKG model for studies at the interface between intestinal and joint inflammation and suggest that arthritogenic variants of PTPN2 amplify the link between gut inflammation and arthritis through conversion of colonic Tregs into exTregs.

Topics: Animals; Arthritis; Autoimmune Diseases; Colitis; Colon; DNA-Binding Proteins; Forkhead Transcription Factors; Gene Expression Regulation; Haploinsufficiency; Humans; Inflammation; Interleukin-17; Intestines; Joints; Mannans; Mice; Mice, Knockout; Protein Tyrosine Phosphatase, Non-Receptor Type 2; Receptors, G-Protein-Coupled; Receptors, Peptide; Sodium Dodecyl Sulfate; T-Lymphocytes, Regulatory

Low-grade intestinal inflammation and alterations of gut barrier integrity are found in patients affected by extraintestinal autoimmune diseases such as type 1 diabetes (T1D), but a direct causal link between enteropathy and triggering of autoimmunity is yet to be established. Here, we found that onset of autoimmunity in preclinical models of T1D is associated with alterations of the mucus layer structure and loss of gut barrier integrity. Importantly, we showed that breakage of the gut barrier integrity in

Topics: Animals; Bacteria; Blood Glucose; Colitis; Diabetes Mellitus, Type 1; Disease Models, Animal; Female; Gastrointestinal Microbiome; Gene Expression; Humans; Intestinal Mucosa; Islets of Langerhans; Mice; Mice, Inbred NOD; Mice, Transgenic; Permeability; Receptors, Antigen, T-Cell; Sodium Dodecyl Sulfate; Survival Analysis; T-Lymphocytes; Transgenes

Foxp3

Topics: Animals; Cell Movement; Cells, Cultured; Colitis; Colon; Disease Models, Animal; Forkhead Transcription Factors; Homeodomain Proteins; Humans; Immunosuppression Therapy; Inflammation; Lymph Nodes; Mice; Mice, Inbred C57BL; Mice, Transgenic; Receptors, Lysosphingolipid; Sodium Dodecyl Sulfate; Sphingosine-1-Phosphate Receptors; T-Lymphocytes, Regulatory; Tumor Suppressor Proteins

Activation of the amino acid starvation response (AAR) increases lifespan and acute stress resistance as well as regulates inflammation. However, the underlying mechanisms remain unclear. Here, we show that activation of AAR pharmacologically by Halofuginone (HF) significantly inhibits production of the proinflammatory cytokine interleukin 1β (IL-1β) and provides protection from intestinal inflammation in mice. HF inhibits IL-1β through general control nonderepressible 2 kinase (GCN2)-dependent activation of the cytoprotective integrated stress response (ISR) pathway, resulting in rerouting of IL-1β mRNA from translationally active polysomes to inactive ribocluster complexes-such as stress granules (SGs)-via recruitment of RNA-binding proteins (RBPs) T cell-restricted intracellular antigen-1(TIA-1)/TIA-1-related (TIAR), which are further cleared through induction of autophagy. GCN2 ablation resulted in reduced autophagy and SG formation, which is inversely correlated with IL-1β production. Furthermore, HF diminishes inflammasome activation through suppression of reactive oxygen species (ROS) production. Our study unveils a novel mechanism by which IL-1β is regulated by AAR and further suggests that administration of HF might offer an effective therapeutic intervention against inflammatory diseases.

Topics: Adaptation, Physiological; Amino Acids; Animals; Autophagy; Cells, Cultured; Colitis; Gene Expression Regulation; Inflammasomes; Interleukin-1beta; Lipopolysaccharides; Macrophages; Mice; Mice, Inbred BALB C; Mice, Inbred C57BL; Piperidines; Protein Biosynthesis; Protein Serine-Threonine Kinases; Protein Synthesis Inhibitors; Quinazolinones; Reactive Oxygen Species; RNA-Binding Proteins; RNA, Messenger; RNA, Small Interfering; Sodium Dodecyl Sulfate; Starvation; Stress, Physiological; T-Cell Intracellular Antigen-1

Fungi represent a significant proportion of the gut microbiota. Aberrant immune responses to fungi are frequently observed in inflammatory bowel diseases (IBD) and colorectal cancer (CRC), and mutations in the fungal-sensing pathways are associated with the pathogenesis of IBD. Fungal recognition receptors trigger downstream signaling via the common adaptor protein CARD9 and the kinase SYK. Here we found that commensal gut fungi promoted inflammasome activation during AOM-DSS-induced colitis. Myeloid cell-specific deletion of Card9 or Syk reduced inflammasome activation and interleukin (IL)-18 maturation and increased susceptibility to colitis and CRC. IL-18 promoted epithelial barrier restitution and interferon-γ production by intestinal CD8

Topics: Animals; CARD Signaling Adaptor Proteins; Cells, Cultured; Colitis; Colonic Neoplasms; Disease Models, Animal; Fungi; Gastrointestinal Microbiome; Humans; Inflammasomes; Inflammatory Bowel Diseases; Interleukin-18; Intestinal Mucosa; Mice; Mice, Inbred C57BL; Mice, Knockout; Myeloid Cells; Signal Transduction; Sodium Dodecyl Sulfate; Syk Kinase

There is a groundswell of interest in using genetically engineered sensor bacteria to study gut microbiota pathways, and diagnose or treat associated diseases. Here, we computationally identify the first biological thiosulfate sensor and an improved tetrathionate sensor, both two-component systems from marine

Topics: Animals; Bacterial Proteins; Biosensing Techniques; Colitis; Colon; Disease Models, Animal; Feces; Gastrointestinal Microbiome; Mice; Shewanella; Sodium Dodecyl Sulfate; Systems Biology; Tetrathionic Acid; Thiosulfates

The gut microbiota regulate susceptibility to multiple human diseases. The Nlrp6-ASC inflammasome is widely regarded as a hallmark host innate immune axis that shapes the gut microbiota composition. This notion stems from studies reporting dysbiosis in mice lacking these inflammasome components when compared with non-littermate wild-type animals. Here, we describe microbial analyses in inflammasome-deficient mice while minimizing non-genetic confounders using littermate-controlled Nlrp6-deficient mice and ex-germ-free littermate-controlled ASC-deficient mice that were all allowed to shape their gut microbiota naturally after birth. Careful microbial phylogenetic analyses of these cohorts failed to reveal regulation of the gut microbiota composition by the Nlrp6- and ASC-dependent inflammasomes. Our results obtained in two geographically separated animal facilities dismiss a generalizable impact of Nlrp6- and ASC-dependent inflammasomes on the composition of the commensal gut microbiota and highlight the necessity for littermate-controlled experimental design in assessing the influence of host immunity on gut microbial ecology.

Topics: Animals; Apoptosis Regulatory Proteins; Bacteria; CARD Signaling Adaptor Proteins; Cells, Cultured; Colitis; Dysbiosis; Female; Gastrointestinal Microbiome; Genetic Background; Immunity, Innate; Inflammasomes; Mice; Mice, Inbred C57BL; Mice, Knockout; Microbiota; Receptors, Cell Surface; RNA, Ribosomal, 16S; Sodium Dodecyl Sulfate

Impairment in gut epithelial integrity and barrier function is associated with many diseases. The homeostasis of intestinal barrier is based on a delicate regulation of epithelial proliferation and differentiation. AMP-activated protein kinase (AMPK) is a master regulator of energy metabolism, and cellular metabolites are intrinsically involved in epigenetic modifications governing cell differentiation. We aimed to evaluate the regulatory role of AMPK on intestinal epithelial development and barrier function. In this study, AMPK activator (AICAR) improved the barrier function of Caco-2 cells as indicated by increased transepithelial electrical resistance and reduced paracellular FITC-dextran permeability; consistently, AICAR enhanced epithelial differentiation and tight junction formation. Transfection of Caco-2 cells with AMPK WT plasmid, which enhances AMPK activity, improved epithelial barrier function and epithelial differentiation, while K45R (AMPK dominant negative mutant) impaired; these changes were correlated with the expression of caudal type homeobox 2 (CDX2), the key transcription factor committing cells to intestinal epithelial lineage. CDX2 deficiency abolished intestinal differentiation promoted by AMPK activation. Mechanistically, AMPK inactivation was associated with polycomb repressive complex 2 regulated enrichment of H3K27me3, the inhibitory histone modification, and lysine-specific histone demethylase-1-mediated reduction of H3K4me3, a permissive histone modification. Those histone modifications provide a mechanistic link between AMPK and CDX2 expression. Consistently, epithelial AMPK knockout in vivo reduced CDX2 expression, impaired intestinal barrier function, integrity and ultrastructure of tight junction, and epithelial cell migration, promoted intestinal proliferation and exaggerated dextran sulfate sodium-induced colitis. In summary, AMPK enhances intestinal barrier function and epithelial differentiation via promoting CDX2 expression, which is partially mediated by altered histone modifications in the Cdx2 promoter.

Topics: Aminoimidazole Carboxamide; AMP-Activated Protein Kinases; Animals; Caco-2 Cells; CDX2 Transcription Factor; Cell Differentiation; Colitis; Colon; Dextrans; Epithelial Cells; Fluorescein-5-isothiocyanate; Gene Expression Regulation; Histone Demethylases; Histones; Humans; Intestinal Mucosa; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Permeability; Polycomb Repressive Complex 2; Promoter Regions, Genetic; Ribonucleotides; Sodium Dodecyl Sulfate; Tight Junctions

Cellular inhibitors of apoptosis proteins (cIAPs) are critical arbiters of cell death and key mediators of inflammation and innate immunity. cIAP2 is frequently overexpressed in colorectal cancer and in regenerating crypts of ulcerative colitis patients. However, its corresponding functions in intestinal homeostasis and underlying mechanisms in disease pathogenesis are poorly understood. We found that mice deficient in cIAP2 exhibited reduced colitis-associated colorectal cancer tumor burden but, surprisingly, enhanced susceptibility to acute and chronic colitis. The exacerbated colitis phenotype of cIAP2-deficient mice was mediated by increased cell death and impaired activation of the regenerative inflammasome-interleukin-18 (IL-18) pathway required for tissue repair following injury. Accordingly, administration of recombinant IL-18 or pharmacological inhibition of caspases or the kinase RIPK1 protected cIAP2-deficient mice from colitis and restored intestinal epithelial barrier architecture. Thus, cIAP2 orchestrates intestinal homeostasis by exerting a dual function in suppressing cell death and promoting intestinal epithelial cell proliferation and crypt regeneration.

Topics: Animals; Azoxymethane; Baculoviral IAP Repeat-Containing 3 Protein; Cell Death; Cell Survival; Colitis; Colon; Colorectal Neoplasms; Gene Expression Regulation; Humans; Inflammasomes; Inhibitor of Apoptosis Proteins; Interleukin-18; Male; Mice; Mice, Knockout; Receptor-Interacting Protein Serine-Threonine Kinases; Signal Transduction; Sodium Dodecyl Sulfate; Ubiquitin-Protein Ligases

Recent advances have shown that the abnormal inflammatory response observed in CD involves an interplay among intestinal microbiota, host genetics and environmental factors. The escalating consumption of fat and sugar in Western countries parallels an increased incidence of CD during the latter 20(th) century. The impact of a HF/HS diet in mice was evaluated for the gut micro-inflammation, intestinal microbiota composition, function and selection of an E. coli population. The HF/HS diet created a specific inflammatory environment in the gut, correlated with intestinal mucosa dysbiosis characterized by an overgrowth of pro-inflammatory Proteobacteria such as E. coli, a decrease in protective bacteria, and a significantly decreased of SCFA concentrations. The expression of GPR43, a SCFA receptor was reduced in mice treated with a HF/HS diet and reduced in CD patients compared with controls. Interestingly, mice treated with an agonist of GPR43 were protected against DSS-induced colitis. Finally, the transplantation of feces from HF/HS treated mice to GF mice increased susceptibility to AIEC infection. Together, our results demonstrate that a Western diet could aggravate the inflammatory process and that the activation of the GPR43 receptor pathway could be used as a new strategy to treat CD patients.

Topics: Animals; Bacterial Adhesion; Benzeneacetamides; Colitis; Crohn Disease; Diet, High-Fat; Diet, Western; Dietary Sucrose; Disease Susceptibility; Dysbiosis; Escherichia coli; Fatty Acids, Volatile; Fecal Microbiota Transplantation; Female; Gastrointestinal Microbiome; Gene Expression Regulation; Gene-Environment Interaction; Humans; Intestinal Mucosa; Male; Mice; Receptors, G-Protein-Coupled; Sodium Dodecyl Sulfate

Uncontrolled canonical Wnt signalling supports colon epithelial tumour expansion and malignant transformation. Understanding the regulatory mechanisms involved is crucial for elucidating the pathogenesis of and will provide new therapeutic targets for colon cancer. Epsins are ubiquitin-binding adaptor proteins upregulated in several human cancers; however, the involvement of epsins in colon cancer is unknown. Here we show that loss of intestinal epithelial epsins protects against colon cancer by significantly reducing the stability of the crucial Wnt signalling effector, dishevelled (Dvl2), and impairing Wnt signalling. Consistently, epsins and Dvl2 are correspondingly upregulated in colon cancer. Mechanistically, epsin binds Dvl2 via its epsin N-terminal homology domain and ubiquitin-interacting motifs and prohibits Dvl2 polyubiquitination and degradation. Our findings reveal an unconventional role for epsins in stabilizing Dvl2 and potentiating Wnt signalling in colon cancer cells to ensure robust colon cancer progression. The pro-carcinogenic role of Epsins suggests that they are potential therapeutic targets to combat colon cancer.

Topics: Adaptor Proteins, Signal Transducing; Adaptor Proteins, Vesicular Transport; Adenocarcinoma; Animals; Azoxymethane; Binding Sites; Colitis; Colon; Colonic Neoplasms; Dishevelled Proteins; Gene Expression Regulation, Neoplastic; HT29 Cells; Humans; Mice; Mice, Knockout; Phosphoproteins; Primary Cell Culture; Protein Binding; Protein Interaction Domains and Motifs; Protein Stability; RNA, Small Interfering; Sodium Dodecyl Sulfate; Wnt Signaling Pathway; Xenograft Model Antitumor Assays

The interleukin-17 (IL-17) family of cytokines has emerged as a critical player in inflammatory diseases. Among them, IL-25 has been shown to be important in allergic inflammation and protection against parasitic infection. Here we have demonstrated that IL-17B, a poorly understood cytokine, functions to inhibit IL-25-driven inflammation. IL-17B and IL-25, both binding to the interleukin-17 receptor B (IL-17RB), were upregulated in their expression after acute colonic inflammation. Individual inhibition of these cytokines revealed opposing functions in colon inflammation: IL-25 was pathogenic but IL-17B was protective. Similarly opposing phenotypes were observed in Citrobacter rodentium infection and allergic asthma. Moreover, IL-25 was found to promote IL-6 production from colon epithelial cells, which was inhibited by IL-17B. Therefore, our data demonstrate that IL-17B is an anti-inflammatory cytokine in the IL-17 family.

Topics: Animals; Anti-Bacterial Agents; Asthma; Cell Line; Citrobacter rodentium; Colitis; Dysbiosis; Enterobacteriaceae Infections; Epithelial Cells; Gene Expression Regulation; Interleukin-17; Interleukin-6; Interleukins; Intestinal Mucosa; Mice; Mice, Inbred C57BL; Mice, Knockout; Ovalbumin; Protein Binding; Receptors, Interleukin-17; Signal Transduction; Sodium Dodecyl Sulfate

The mammalian target of rapamycin (mTOR) signaling pathway integrates environmental cues to regulate cell growth and survival through various mechanisms. However, how mTORC1 responds to acute inflammatory signals to regulate bowel regeneration is still obscure. In this study, we investigated the role of mTORC1 in acute inflammatory bowel disease. Inhibition of mTORC1 activity by rapamycin treatment or haploinsufficiency of Rheb through genetic modification in mice impaired intestinal cell proliferation and induced cell apoptosis, leading to high mortality in dextran sodium sulfate- and 2,4,6-trinitrobenzene sulfonic acid-induced colitis models. Through bone marrow transplantation, we found that mTORC1 in nonhematopoietic cells played a major role in protecting mice from colitis. Reactivation of mTORC1 activity by amino acids had a positive therapeutic effect in mTORC1-deficient Rheb(+/-) mice. Mechanistically, mTORC1 mediated IL-6-induced Stat3 activation in intestinal epithelial cells to stimulate the expression of downstream targets essential for cell proliferation and tissue regeneration. Therefore, mTORC1 signaling critically protects against inflammatory bowel disease through modulation of inflammation-induced Stat3 activity. As mTORC1 is an important therapeutic target for multiple diseases, our findings will have important implications for the clinical usage of mTORC1 inhibitors in patients with acute inflammatory bowel disease.

Topics: Animals; Bone Marrow Transplantation; Caco-2 Cells; Cell Proliferation; Colitis; Gene Expression Regulation; Haploinsufficiency; Humans; Interleukin-6; Mechanistic Target of Rapamycin Complex 1; Mice; Mice, Inbred C57BL; Mice, Transgenic; Monomeric GTP-Binding Proteins; Multiprotein Complexes; Neuropeptides; Ras Homolog Enriched in Brain Protein; Signal Transduction; Sirolimus; Sodium Dodecyl Sulfate; STAT3 Transcription Factor; Survival Analysis; TOR Serine-Threonine Kinases; Trinitrobenzenesulfonic Acid

Control of colorectal cancer needs to be tailored to its etiology. Tumor promotion mechanisms in colitis-associated colon cancer differ somewhat from the mechanisms involved in hereditary and sporadic colorectal cancer. Unlike sporadic or inherited tumors, some experimental models show that colitis-associated colon tumors do not require cyclooxygenase (COX) expression for progression, and non-steroidal anti-inflammatory drugs (NSAIDs) which prevent sporadic or inherited colon cancer do not prevent colitis-associated colon cancer. We report that myeloperoxidase (MPO), an ancestor of the COX isoenzymes, is a determinant of colitis-associated colon tumors in Apc(Min/+) mice. During experimentally induced colitis, inhibition of MPO by resorcinol dampened colon tumor development. Conversely, in the bowels of Apc(Min/+) mice without colitis, resorcinol administration or 'knockout' of MPO gene coincided with a slight, but discernible increase in colon tumor incidence. Acrolein, a by-product of MPO catalysis, formed a covalent adduct with the phosphatase tensin homolog (PTEN) tumor suppressor and enhanced the activity of the Akt kinase proto-oncogene in vitro and in vivo. Thus, MPO may be an important determinant of diet and inflammation on colon cancer risk via its effect on endogenous exposure to oxidants and acrolein. We propose a hypothetical model to explain an apparent dichotomy between colon tumor occurrence and MPO inhibition in inflamed versus non-inflamed colons.

Topics: Acrolein; Animals; Colitis; Colonic Neoplasms; Female; Gene Expression; Inflammation; Male; Mice; Mice, Transgenic; Oxidation-Reduction; Peroxidase; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Resorcinols; RNA, Small Interfering; Sodium Dodecyl Sulfate

Indoleamine 2,3 -dioxygenase 1 (IDO1) catalyzes L-tryptophan to kynurenine in the first and rate-limiting step of tryptophan metabolism. IDO1 is expressed widely throughout the body, with especially high expression in colonic intestinal tissues. To examine the role of IDO1 in the colon, transcriptome analysis was performed in both Ido1(-/-) and Ido1(+/+) mice. Gene set enrichment analysis identified the Inflammatory Response as the most significant category modulated by the absence of IDO1. This observation prompted us to further investigate the function of IDO1 in the development of tissue inflammation. By using DSS-induced experimental colitis mice models, we found that the disease in Ido1(-/-) mice was less severe than in Ido1(+/+) mice. Pharmacological inhibition of IDO1 by L-1MT attenuated the severity of DSS-colitis as well. Transcriptome analyses revealed that pathways involving TLR and NF-kB signaling were significantly down-regulated by the absence of IDO1. Furthermore, dramatic changes in TLR and NF-kB signaling resulted in substantial changes in the expression of many inflammatory cytokines and chemokines. Numbers of inflammatory cells in colon and peripheral blood were reduced in IDO1 deficiency. These findings suggest that IDO1 plays important roles in producing inflammatory responses and modulating transcriptional networks during the development of colitis.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Colitis; Colon; Enzyme Inhibitors; Female; Gene Expression Regulation; Gene Regulatory Networks; Indoleamine-Pyrrole 2,3,-Dioxygenase; Mice; Mice, Inbred C57BL; Mice, Knockout; Myeloid Differentiation Factor 88; NF-kappa B; Severity of Illness Index; Signal Transduction; Sodium Dodecyl Sulfate; Toll-Like Receptor 2; Toll-Like Receptor 6; Transcription, Genetic; Transcriptome; Tryptophan

B7-H1 (PD-L1) on immune cells plays an important role in T cell coinhibition by binding its receptor PD-1. Here, we show that both human and mouse intestinal epithelium express B7-H1 and that B7-H1-deficient mice are highly susceptible to dextran sodium sulfate (DSS)- or trinitrobenzenesulfonic acid (TNBS)-induced gut injury. B7-H1 deficiency during intestinal inflammation leads to high mortality and morbidity, which are associated with severe pathological manifestations in the colon, including loss of epithelial integrity and overgrowth of commensal bacteria. Results from bone marrow chimeric and knockout mice show that B7-H1 expressed on intestinal parenchyma, but not on hematopoietic cells, controls intestinal inflammation in an adaptive immunity-independent fashion. Finally, we demonstrate that B7-H1 dampened intestinal inflammation by inhibiting tumor necrosis factor α (TNF-α) production and by stimulating interleukin 22 secretion from CD11c(+)CD11b(+) lamina propria cells. Thus, our data uncover a mechanism through which intestinal tissue-expressed B7-H1 functions as an essential ligand for innate immune cells to prevent gut inflammation.

Topics: Animals; Bone Marrow Cells; Colitis; Humans; Immunity, Innate; Inflammation; Interleukin-22; Interleukins; Intestinal Mucosa; Mice; Mice, Inbred C57BL; Programmed Cell Death 1 Receptor; Sodium Dodecyl Sulfate; Trinitrobenzenesulfonic Acid; Tumor Necrosis Factor-alpha

Dysfunction of Paneth and goblet cells in the intestine contributes to inflammatory bowel disease (IBD) and colitis-associated colorectal cancer (CAC). Here, we report a role for the NAD+-dependent histone deacetylase SIRT1 in the control of anti-bacterial defense. Mice with an intestinal specific Sirt1 deficiency (Sirt1int-/-) have more Paneth and goblet cells with a consequent rearrangement of the gut microbiota. From a mechanistic point of view, the effects on mouse intestinal cell maturation are mediated by SIRT1-dependent changes in the acetylation status of SPDEF, a master regulator of Paneth and goblet cells. Our results suggest that targeting SIRT1 may be of interest in the management of IBD and CAC.

Topics: Animals; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Cell Differentiation; Cell Line; Colitis; Colorectal Neoplasms; Gene Deletion; Gene Expression Regulation, Neoplastic; Goblet Cells; Humans; Mice; Mice, Knockout; Paneth Cells; Proto-Oncogene Proteins c-ets; Signal Transduction; Sirtuin 1; Sodium Dodecyl Sulfate

Saccharomyces boulardii (Sb) can protect against intestinal injury and tumor formation, but how this probiotic yeast controls protective mucosal host responses is unclear. Angiogenesis is an integral process of inflammatory responses in inflammatory bowel diseases (IBD) and required for mucosal remodeling during restitution. The aim of this study was to determine whether Sb alters VEGFR (vascular endothelial growth factor receptor) signaling, a central regulator of angiogenesis.. HUVEC were used to examine the effects of Sb on signaling and on capillary tube formation (using the ECMatrix™ system). The effects of Sb on VEGF-mediated angiogenesis were examined in vivo using an adenovirus expressing VEGF-A(164) in the ears of adult nude mice (NuNu). The effects of Sb on blood vessel volume branching and density in DSS-induced colitis was quantified using VESsel GENeration (VESGEN) software.. 1) Sb treatment attenuated weight-loss (p<0.01) and histological damage (p<0.01) in DSS colitis. VESGEN analysis of angiogenesis showed significantly increased blood vessel density and volume in DSS-treated mice compared to control. Sb treatment significantly reduced the neo-vascularization associated with acute DSS colitis and accelerated mucosal recovery restoration of the lamina propria capillary network to a normal morphology. 2) Sb inhibited VEGF-induced angiogenesis in vivo in the mouse ear model. 3) Sb also significantly inhibited angiogenesis in vitro in the capillary tube assay in a dose-dependent manner (p<0.01). 4) In HUVEC, Sb reduced basal VEGFR-2 phosphorylation, VEGFR-2 phosphorylation in response to VEGF as well as activation of the downstream kinases PLCγ and Erk1/2.. Our findings indicate that the probiotic yeast S boulardii can modulate angiogenesis to limit intestinal inflammation and promote mucosal tissue repair by regulating VEGFR signaling.

Topics: Adenoviridae; Animals; Colitis; Female; Gene Expression Regulation; Genetic Vectors; Humans; Inflammation; Intestinal Mucosa; Intestines; Mice; Mice, Nude; Mitogen-Activated Protein Kinase 1; Mitogen-Activated Protein Kinase 3; Neovascularization, Pathologic; Phospholipase C gamma; Phosphorylation; Probiotics; Saccharomyces; Signal Transduction; Sodium Dodecyl Sulfate; Vascular Endothelial Growth Factor A; Vascular Endothelial Growth Factor Receptor-2

The microbiota contributes to the induction of both effector and regulatory responses in the gastrointestinal (GI) tract. However, the mechanisms controlling these distinct properties remain poorly understood. We previously showed that commensal DNA promotes intestinal immunity. Here, we find that the capacity of bacterial DNA to stimulate immune responses is species specific and correlated with the frequency of motifs known to exert immunosuppressive function. In particular, we show that the DNA of Lactobacillus species, including various probiotics, is enriched in suppressive motifs able to inhibit lamina propria dendritic cell activation. In addition, immunosuppressive oligonucleotides sustain T(reg) cell conversion during inflammation and limit pathogen-induced immunopathology and colitis. Altogether, our findings identify DNA-suppressive motifs as a molecular ligand expressed by commensals and support the idea that a balance between stimulatory and regulatory DNA motifs contributes to the induction of controlled immune responses in the GI tract and gut immune homeostasis. Further, our findings suggest that the endogenous regulatory capacity of DNA motifs enriched in some commensal bacteria could be exploited for therapeutic purposes.

Topics: Animals; Anti-Bacterial Agents; Colitis; CpG Islands; Cytokines; Dendritic Cells; DNA, Bacterial; Encephalitozoon cuniculi; Escherichia coli; Immunity, Mucosal; Immunologic Factors; Intestinal Mucosa; Lactobacillus; Mice; Mice, Transgenic; Nucleotide Motifs; Oligodeoxyribonucleotides; Probiotics; Sodium Dodecyl Sulfate; T-Lymphocytes, Regulatory; Toxoplasma

Epidemiological studies of Clostridium difficile diarrhoeal disease have been hindered by the lack of a typing scheme for this organism. A typing method based on the incorporation of sulphur-35-labelled methionine into cellular proteins and their separation by sodium dodecylsulphate/polyacrylamide gel electrophoresis showed clear pattern differences between strains, and nine distinct groups within the C difficile species were established. 98% of 250 clinical strains derived from four hospitals were typable. Group X was the commonest group and was associated with outbreaks of pseudomembranous colitis and antibiotic-associated colitis in two hospitals. Groups A-D were isolated predominantly from mothers and newborn infants. In outbreaks of antibiotic-associated colitis in oncology and orthopaedic wards the same strains, group X and group E, respectively, were isolated from patients and their environment, providing strong evidence of cross-infection between patients and of hospital acquisition of C difficile.

Topics: Adult; Anti-Bacterial Agents; Autoradiography; Bacterial Proteins; Bacteriological Techniques; Clostridium; Colitis; Cross Infection; Electrophoresis, Polyacrylamide Gel; Enterocolitis, Pseudomembranous; Female; Humans; Infant, Newborn; Methionine; Sodium Dodecyl Sulfate; Sulfur Radioisotopes