Synbindin restrains proinflammatory macrophage activation against microbiota and mucosal inflammation during colitis

ObjectiveAs a canonical membrane tethering factor, the function of synbindin has been expanding and indicated in immune response. Here, we investigated the role of synbindin in the regulation of toll-like receptor 4 (TLR4) signalling and macrophage response to microbiota during colitis.DesignThree distinct mouse models allowing global, myeloid-specific or intestinal epithelial cell-specific synbindin heterozygous deletion were constructed and applied to reveal the function of synbindin during dextran sodium sulfate (DSS) colitis. Effects of synbindin on TLR4 signalling and macrophage activation in response to bacterial lipopolysaccharide (LPS) or Fusobacterium nucleatum were evaluated. The colocalisation and interaction between synbindin and Rab7b were determined by immunofluorescence and coimmunoprecipitation. Synbindin expression in circulating monocytes and intestinal mucosal macrophages of patients with active IBD was detected.ResultsGlobal synbindin haploinsufficiency greatly exacerbated DSS-induced intestinal inflammation. The increased susceptibility to DSS was abolished by gut microbiota depletion, while phenocopied by specific synbindin heterozygous deletion in myeloid cells rather than intestinal epithelial cells. Profoundly aberrant proinflammatory gene signatures and excessive TLR4 signalling were observed in macrophages with synbindin interference in response to bacterial LPS or Fusobacterium nucleatum. Synbindin was significantly increased in intestinal mucosal macrophages and circulating monocytes from both mice with DSS colitis and patients with active IBD. Interleukin 23 and granulocyte-macrophage colony-stimulating factor were identified to induce synbindin expression. Mechanistic characterisation indicated that synbindin colocalised and directly interacted with Rab7b, which coordinated the endosomal degradation pathway of TLR4 for signalling termination.ConclusionSynbindin was a key regulator of TLR4 signalling and restrained the proinflammatory macrophage activation against microbiota during colitis.

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The phytonutrient cinnamaldehyde limits intestinal inflammation and enteric parasite infection

10.1101/2021.03.02.433624 ◽

2021 ◽

Author(s):

Ling Zhu ◽

Audrey I.S. Andersen-Civil ◽

Laura J. Myhill ◽

Stig M. Thamsborg ◽

Witold Kot ◽

...

Keyword(s):

Gut Microbiota ◽

Metabolic Diseases ◽

Intestinal Inflammation ◽

Inflammatory Responses ◽

Host Responses ◽

Mucosal Inflammation ◽

Enteric Infection ◽

Intestinal Epithelial ◽

Mesenteric Lymph Nodes

AbstractPhytonutrients such as cinnamaldehyde (CA) have been studied for their effects on metabolic diseases, but their influence on mucosal inflammation and immunity to enteric infection are not well documented. Here, we show that consumption of CA significantly down-regulates transcriptional pathways connected to inflammation in the small intestine of mice. During infection with the enteric helminth Heligomosomoides polygyrus, CA-treated mice displayed higher growth rates and less worms, concomitant with altered T-cell populations in mesenteric lymph nodes. Furthermore, infection-induced changes in gene pathways connected to cell cycle and mitotic activity were counteracted by CA. Mechanically, CA did not appear to exert activity through a prebiotic effect, as CA treatment did not significantly change the composition of the gut microbiota. Instead, in vitro experiments showed that CA directly induced xenobiotic metabolizing pathways in intestinal epithelial cells and suppressed endotoxin-induced inflammatory responses in macrophages. Thus, CA down-regulates inflammatory pathways in the intestinal mucosa and regulates host responses to enteric infection. These properties appear to be largely independent of the gut microbiota and instead connected to CA’s ability to induce antioxidant pathways in intestinal cells. Our results encourage further investigation into the use of CA and related phytonutrients as functional food components to promote intestinal health in humans and animals.

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Deciphering the combinatorial influence of diet and the microbiota on experimental colitis

10.1101/117929 ◽

2017 ◽

Author(s):

Sean R. Llewellyn ◽

Graham J. Britton ◽

Eduardo J. Contijoch ◽

Arthur Mortha ◽

Jean-Frederic Colombel ◽

...

Keyword(s):

Dietary Protein ◽

Intestinal Inflammation ◽

High Protein Diet ◽

Experimental Colitis ◽

Mucosal Inflammation ◽

Germ Free ◽

Dss Colitis ◽

Microbial Density ◽

Specific Pathogen ◽

Host Physiology

AbstractBackground & AimsThe complex interactions between diet and the microbiota that influence mucosal inflammation and inflammatory bowel disease are poorly understood. Experimental colitis models provide the opportunity to control and systematically perturb diet and the microbiota in parallel to quantify the contributions between multiple dietary ingredients and the microbiota on host physiology and colitis.MethodsTo examine the interplay of diet and the gut microbiota on host health and colitis, we fed over 40 different diets with varied macronutrient sources and concentrations to specific pathogen free or germ free mice either in the context of healthy, unchallenged animals or colitis models (dextran sodium sulfate (DSS) and T cell transfer).ResultsDiet influenced physiology in both health and colitis across all models, with the concentration of protein and psyllium fiber having the most profound effects. Increasing dietary protein elevated gut microbial density and worsened DSS colitis severity. Depleting gut microbial density by using germ-free animals or antibiotics negated the effect of a high protein diet. Psyllium fiber influenced host physiology and attenuated colitis severity through microbiota-dependent and microbiota-independent mechanisms. Combinatorial perturbations to dietary protein and psyllium fiber in parallel explain most variation in gut microbial density, intestinal permeability, and DSS colitis severity, and changes in one ingredient can be offset by changes in the other.ConclusionsOur results demonstrate the importance of examining complex mixtures of nutrients to understand the role of diet in intestinal inflammation.

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Blockage of bacterial FimH prevents mucosal inflammation associated with Crohn’s disease

Microbiome ◽

10.1186/s40168-021-01135-5 ◽

2021 ◽

Vol 9 (1) ◽

Author(s):

Grégoire Chevalier ◽

Arnaud Laveissière ◽

Guillaume Desachy ◽

Nicolas Barnich ◽

Adeline Sivignon ◽

...

Keyword(s):

Crohn’S Disease ◽

Crohn's Disease ◽

Gut Microbiome ◽

Bacterial Adhesion ◽

Intestinal Inflammation ◽

Mucosal Inflammation ◽

Intestinal Epithelial ◽

E Coli ◽

Promising Therapeutic Approach ◽

Activity Dependent

Abstract Background An Escherichia coli (E. coli) pathotype with invasive properties, first reported by Darfeuille-Michaud and termed adherent-invasive E. coli (AIEC), was shown to be prevalent in up to half the individuals with Crohn’s Disease (CD), suggesting that these bacteria could be involved in the pathophysiology of CD. Among the genes related to AIEC pathogenicity, fim has the potential to generate an inflammatory reaction from the intestinal epithelial cells and macrophages, as it interacts with TLR4, inducing the production of inflammatory cytokines independently of LPS. Therefore, targeting the bacterial adhesion of FimH-expressing bacteria seems a promising therapeutic approach, consisting of disarming bacteria without killing them, representing a selective strategy to suppress a potentially critical trigger of intestinal inflammation, without disturbing the intestinal microbiota. Results We analyzed the metagenomic composition of the gut microbiome of 358 patients with CD from two different cohorts and characterized the presence of FimH-expressing bacteria. To assess the pathogenic role of FimH, we used human intestinal explants and tested a specific FimH blocker to prevent bacterial adhesion and associated inflammation. We observed a significant and disease activity-dependent enrichment of Enterobacteriaceae in the gut microbiome of patients with CD. Bacterial FimH expression was functionally confirmed in ileal biopsies from 65% of the patients with CD. Using human intestinal explants, we further show that FimH is essential for adhesion and to trigger inflammation. Finally, a specific FimH-blocker, TAK-018, inhibits bacterial adhesion to the intestinal epithelium and prevents inflammation, thus preserving mucosal integrity. Conclusions We propose that TAK-018, which is safe and well tolerated in humans, is a promising candidate for the treatment of CD and in particular in preventing its recurrence.

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Microbial regulation of hexokinase 2 links mitochondrial metabolism and cell death in colitis

10.1101/2020.12.22.423953 ◽

2020 ◽

Author(s):

Jacob Hamm ◽

Finn Hinrichsen ◽

Lena Schröder ◽

Neha Mishra ◽

Kensuke Shima ◽

...

Keyword(s):

Cell Death ◽

Protective Factor ◽

Intestinal Inflammation ◽

Intestinal Barrier ◽

Intestinal Epithelial ◽

Acute Colitis ◽

Oral Supplementation ◽

Dss Colitis ◽

Cell Death Signaling ◽

Therapeutic Avenue

SummaryHexokinases (HK) catalyze the first step of glycolysis and thereby limit its pace. HK2 is highly expressed in the gut epithelium, plays a role in immune responses and is upregulated in inflammation and ulcerative colitis 1–3. Here, we examined the microbial regulation of HK2 and its impact on intestinal inflammation by generating mice lacking HK2 specifically in intestinal epithelial cells (Hk2ΔIEC). Hk2ΔIEC mice were less susceptible to acute intestinal inflammation upon challenge with dextran sodium sulfate (DSS). Analyzing the epithelial transcriptome from Hk2ΔIEC mice during acute colitis revealed downregulation of cell death signaling and mitochondrial dysfunction dependent on loss of HK2. Using intestinal organoids derived from Hk2ΔIEC mice and Caco-2 cells lacking HK2, we identified peptidyl-prolyl cis-trans isomerase (PPIF) as a key target of HK2-mediated regulation of mitochondrial permeability and repression of cell-death during intestinal inflammation. The microbiota strongly regulated HK2 expression and activity. The microbially-derived short-chain fatty acid (SCFA) butyrate repressed HK2 expression and oral supplementation protected wildtype but not Hk2ΔIEC mice from DSS colitis. Our findings define a novel mechanism how butyrate may act as a protective factor for intestinal barrier homeostasis and suggest targeted HK2 inhibition as a promising therapeutic avenue in intestinal inflammation.

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Lactobacillus acidophilus counteracts enteropathogenic E. coli-induced inhibition of butyrate uptake in intestinal epithelial cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00186.2015 ◽

2015 ◽

Vol 309 (7) ◽

pp. G602-G607 ◽

Cited By ~ 27

Author(s):

Anoop Kumar ◽

Waddah A. Alrefai ◽

Alip Borthakur ◽

Pradeep K. Dudeja

Keyword(s):

Cell Surface ◽

Intestinal Inflammation ◽

Apical Cell ◽

Monocarboxylate Transporter ◽

Mucosal Inflammation ◽

Intestinal Epithelial ◽

Monocarboxylate Transporter 1 ◽

E Coli ◽

Fatty Acid Metabolite

Butyrate, a key short-chain fatty acid metabolite of colonic luminal bacterial action on dietary fiber, serves as a primary fuel for the colonocytes, ameliorates mucosal inflammation, and stimulates NaCl absorption. Absorption of butyrate into the colonocytes is essential for these intracellular effects. Monocarboxylate transporter 1 (MCT1) plays a major role in colonic luminal butyrate absorption. Previous studies (Tan J, McKenzie C, Potamitis M, Thorburn AN, Mackay CR, Macia L. Adv Immunol 121: 91–119, 2014.) showed decreased MCT1 expression and function in intestinal inflammation. We have previously shown (Borthakur A, Gill RK, Hodges K, Ramaswamy K, Hecht G, Dudeja PK. Am J Physiol Gastrointest Liver Physiol 290: G30–G35, 2006.) impaired butyrate absorption in human intestinal epithelial Caco-2 cells due to decreased MCT1 level at the apical cell surface following enteropathogenic E. coli (EPEC) infection. Current studies, therefore, examined the potential role of probiotic Lactobacilli in stimulating MCT1-mediated butyrate uptake and counteracting EPEC inhibition of MCT1 function. Of the five species of Lactobacilli, short-term (3 h) treatment with L. acidophilus (LA) significantly increased MCT1-mediated butyrate uptake in Caco-2 cells. Heat-killed LA was ineffective, whereas the conditioned culture supernatant of LA (LA-CS) was equally effective in stimulating MCT1 function, indicating that the effects are mediated by LA-secreted soluble factor(s). Furthermore, LA-CS increased apical membrane levels of MCT1 protein via decreasing its basal endocytosis, suggesting that LA-CS stimulation of butyrate uptake could be secondary to increased levels of MCT1 on the apical cell surface. LA-CS also attenuated EPEC inhibition of butyrate uptake and EPEC-mediated endocytosis of MCT1. Our studies highlight distinct role of specific LA-secreted molecules in modulating colonic butyrate absorption.

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Prostaglandin E2 receptor PTGER4-expressing macrophages promote intestinal epithelial barrier regeneration upon inflammation

Gut ◽

10.1136/gutjnl-2020-322146 ◽

2021 ◽

pp. gutjnl-2020-322146

Author(s):

Yi Rang Na ◽

Daun Jung ◽

Michelle Stakenborg ◽

Hyeri Jang ◽

Gyo Jeong Gu ◽

...

Keyword(s):

Intestinal Inflammation ◽

Mucosal Healing ◽

Epithelial Barrier ◽

Prostaglandin E ◽

Intestinal Epithelial ◽

Intestinal Epithelial Barrier ◽

Epithelial Regeneration ◽

Dss Colitis ◽

Differentiation And Proliferation

ObjectiveDysfunctional resolution of intestinal inflammation and altered mucosal healing are essential features in the pathogenesis of inflammatory bowel disease (IBD). Intestinal macrophages are vital in the process of inflammation resolution, but the mechanisms underlying their mucosal healing capacity remain elusive.DesignWe investigated the role of the prostaglandin E2 (PGE2) receptor PTGER4 on the differentiation of intestinal macrophages in patients with IBD and mouse models of intestinal inflammation. We studied mucosal healing and intestinal epithelial barrier regeneration in Csf1r-iCre Ptger4fl/fl mice during dextran sulfate sodium (DSS)-induced colitis. The effect of PTGER4+ macrophage secreted molecules was investigated on epithelial organoid differentiation.ResultsHere, we describe a subset of PTGER4-expressing intestinal macrophages with mucosal healing properties both in humans and mice. Csf1r-iCre Ptger4fl/fl mice showed defective mucosal healing and epithelial barrier regeneration in a model of DSS colitis. Mechanistically, an increased mucosal level of PGE2 triggers chemokine (C-X-C motif) ligand 1 (CXCL1) secretion in monocyte-derived PTGER4+ macrophages via mitogen-activated protein kinases (MAPKs). CXCL1 drives epithelial cell differentiation and proliferation from regenerating crypts during colitis. Specific therapeutic targeting of macrophages with liposomes loaded with an MAPK agonist augmented the production of CXCL1 in vivo in conditional macrophage PTGER4-deficient mice, restoring their defective epithelial regeneration and favouring mucosal healing.ConclusionPTGER4+ intestinal macrophages are essential for supporting the intestinal stem cell niche and regeneration of the injured epithelium. Our results pave the way for the development of a new class of therapeutic targets to promote macrophage healing functions and favour remission in patients with IBD.

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Thrombospondin 1 Modulates Monocyte Properties to Suppress Intestinal Mucosal Inflammation

Journal of Innate Immunity ◽

10.1159/000398799 ◽

2015 ◽

Vol 7 (6) ◽

pp. 601-611 ◽

Cited By ~ 3

Author(s):

Lei-Lei Fang ◽

Hai-Qiong Yu ◽

Rui-Jin Wu ◽

Chong He ◽

Meng Li ◽

...

Keyword(s):

Epithelial Cells ◽

Transforming Growth Factor ◽

Intestinal Inflammation ◽

Inflammatory Responses ◽

Intestinal Epithelial Cells ◽

Experimental Colitis ◽

Mucosal Inflammation ◽

Intestinal Epithelial ◽

Thrombospondin 1 ◽

Chronic Intestinal Inflammation

Monocytes (Mos) play an important role in the pathogenesis of intestinal mucosal inflammation. This study aims to investigate the mechanism by which the intestinal epithelial cell-derived thrombospondin 1 (TSP1) modulates Mo properties and regulates intestinal inflammatory responses. In this study, the production of TSP1 by intestinal epithelial cells was evaluated by quantitative real-time PCR and Western blotting. The properties of Mos were analyzed by flow cytometry. A mouse model of colitis was created to assess the role of epithelium-derived TSP1 in the suppression of intestinal inflammation. The results demonstrated that mouse intestinal epithelial cells (IECs) expressed TSP1, which was markedly upregulated by butyrate or feeding with Clostridium butyricum. Coculture of the butyrate-primed IECs and Mos or exposure of Mos to TSP1 in the culture induced the expression of transforming growth factor (TGF)-β in Mos. These TGF-β+ Mos had tolerogenic properties that could promote generation of inducible regulatory T cells. Adoptive transfer with TSP1-primed Mos, or feeding C. butyricum could prevent experimental colitis in mice. In summary, C. butyricum induces intestinal epithelial cells to produce TSP1 and induces TGF-β+ Mos, which further suppress experimental colitis in mice. The results implicate that the administration of C. butyricum or butyrate may have the potential to ameliorate chronic intestinal inflammation through inducing immunosuppressive Mos.

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Enteric neural pathways mediate the anti-inflammatory actions of glucagon-like peptide 2

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00530.2006 ◽

2007 ◽

Vol 293 (1) ◽

pp. G211-G221 ◽

Cited By ~ 123

Author(s):

David L. Sigalet ◽

Laurie E. Wallace ◽

Jens J. Holst ◽

Gary R. Martin ◽

Tatsuru Kaji ◽

...

Keyword(s):

Intestinal Inflammation ◽

Concomitant Administration ◽

Mucosal Inflammation ◽

Trinitrobenzene Sulfonic Acid ◽

Neural Pathways ◽

Submucosal Plexus ◽

Dss Colitis ◽

Glucagon Like Peptide ◽

Anti Inflammatory ◽

Oxide Synthase

Glucagon-like peptide-2 (GLP-2) is an important regulator of nutritional absorptive capacity with anti-inflammatory actions. We hypothesized that GLP-2 reduces intestinal mucosal inflammation by activation of vasoactive intestinal polypeptide (VIP) neurons of the submucosal plexus. Ileitis or colitis was induced in rats by injection of trinitrobenzene sulfonic acid (TNBS), or colitis was induced by administration of dextran sodium sulfate (DSS) in drinking water. Subsets of animals received (1–33)-GLP-2 (50 μg/kg sc bid) either immediately or 2 days after the establishment of inflammation and were followed for 3–5 days. The involvement of VIP neurons was assessed by concomitant administration of GLP-2 and the VIP antagonist [Lys1-Pro2,5-Arg3,4-Tyr6]VIP and by immunohistochemical labeling of GLP-2-activated neurons. In all models, GLP-2 treatment, whether given immediately or delayed until inflammation was established, resulted in significant improvements in animal weights, mucosal inflammation indices (myeloperoxidase levels, histological mucosal scores), and reduced levels of inflammatory cytokines (IFN-γ, TNF-α, IL-1β) and inducible nitric oxide synthase, with increased levels of IL-10 in TNBS ileitis and DSS colitis. Reduced rates of crypt cell proliferation and of apoptosis within crypts in inflamed tissues were also noted with GLP-2 treatment. These effects were abolished with coadministration of GLP-2 and the VIP antagonist. GLP-2 was shown to activate neurons and to increase the number of cells expressing VIP in the submucosal plexus of the ileum. These findings suggest that GLP-2 acts as an anti-inflammatory agent through activation of enteric VIP neurons, independent of proliferative effects. They support further studies to examine the role of neural signaling in the regulation of intestinal inflammation.

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Matrix metalloproteinase 9-induced increase in intestinal epithelial tight junction permeability contributes to the severity of experimental DSS colitis

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00256.2015 ◽

2015 ◽

Vol 309 (12) ◽

pp. G988-G997 ◽

Cited By ~ 48

Author(s):

Prashant Nighot ◽

Rana Al-Sadi ◽

Manmeet Rawat ◽

Shuhong Guo ◽

D. Martin Watterson ◽

...

Keyword(s):

Epithelial Cell ◽

Protein Expression ◽

Barrier Function ◽

Intestinal Inflammation ◽

Intestinal Barrier ◽

Intestinal Barrier Function ◽

Intestinal Epithelial ◽

Dss Colitis

Recent studies have implicated a pathogenic role for matrix metalloproteinases 9 (MMP-9) in inflammatory bowel disease. Although loss of epithelial barrier function has been shown to be a key pathogenic factor for the development of intestinal inflammation, the role of MMP-9 in intestinal barrier function remains unclear. The aim of this study was to investigate the role of MMP-9 in intestinal barrier function and intestinal inflammation. Wild-type (WT) and MMP-9−/−mice were subjected to experimental dextran sodium sulfate (DSS) colitis by administration of 3% DSS in drinking water for 7 days. The mouse colonic permeability was measured in vivo by recycling perfusion of the entire colon using fluorescently labeled dextran. The DSS-induced increase in the colonic permeability was accompanied by an increase in intestinal epithelial cell MMP-9 expression in WT mice. The DSS-induced increase in intestinal permeability and the severity of DSS colitis was found to be attenuated in MMP-9−/−mice. The colonic protein expression of myosin light chain kinase (MLCK) and phospho-MLC was found to be significantly increased after DSS administration in WT mice but not in MMP-9−/−mice. The DSS-induced increase in colonic permeability and colonic inflammation was attenuated in MLCK−/−mice and MLCK inhibitor ML-7-treated WT mice. The DSS-induced increase in colonic surface epithelial cell MLCK mRNA was abolished in MMP-9−/−mice. Lastly, increased MMP-9 protein expression was detected within the colonic surface epithelial cells in ulcerative colitis cases. These data suggest a role of MMP-9 in modulation of colonic epithelial permeability and inflammation via MLCK.

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