RESUMEN
The uterus is a unique mucosal site where immune responses are balanced to be permissive of a fetus, yet protective against infections. Regulation of natural killer (NK) cell responses in the uterus during infection is critical, yet no studies have identified uterine-specific factors that control NK cell responses in this immune-privileged site. We show that the constitutive expression of IFNε in the uterus plays a crucial role in promoting the accumulation, activation, and IFNγ production of NK cells in uterine tissue during Chlamydia infection. Uterine epithelial IFNε primes NK cell responses indirectly by increasing IL-15 production by local immune cells and directly by promoting the accumulation of a pre-pro-like NK cell progenitor population and activation of NK cells in the uterus. These findings demonstrate the unique features of this uterine-specific type I IFN and the mechanisms that underpin its major role in orchestrating innate immune cell protection against uterine infection.
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Células Asesinas Naturales , Útero , Femenino , Humanos , Feto , InterferonesRESUMEN
AIM: The gastrointestinal bile acid (BA)/microbiota axis has emerged as a potential mediator of health and disease, particularly in relation to pathologies such as inflammatory bowel disease (IBD) and colorectal cancer. Whilst it presents an exciting new avenue for therapies, it has not yet been characterized in surgical resection of the ileum, where BA reabsorption occurs. The identification of BA/microbiota signatures may provide future therapies with perioperative personalized medicine. In this work we conduct a systematic review with the aim of investigating the microbiome and BA changes that are associated with resection of the ileum. METHOD: The databases included were MEDLINE, EMBASE, Web of Science and Cochrane libraries. The outcomes of interest were faecal microbiome and BA signatures after ileal resection. RESULTS: Of the initial 3106 articles, three studies met the inclusion/exclusion criteria for data extraction. A total of 257 patients (46% surgery, 54% nonsurgery controls) were included in the three studies. Two studies included patients with short bowel syndrome and the other included patients with IBD. Large-scale microbiota changes were reported. In general, alpha diversity had decreased amongst patients with ileal surgery. Phylum-level changes included decreased Bacteroidetes and increased Proteobacteria and Fusobacteria in patients with an intestinal resection. Surgery was associated with increased total faecal BAs, cholic acid and chenodeoxycholic acid. There were decreases in deoxycholic acid and glycine and taurine conjugated bile salts. Integrated BA and microbiota data identified correlations with several bacterial families and BA. CONCLUSION: The BA/microbiota axis is still a novel area with minimal observational data in surgery. Further mechanistic research is necessary to further explore this and identify its role in improving perioperative outcomes.
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Ácidos y Sales Biliares , Heces , Microbioma Gastrointestinal , Íleon , Enfermedades Inflamatorias del Intestino , Humanos , Ácidos y Sales Biliares/metabolismo , Microbioma Gastrointestinal/fisiología , Íleon/cirugía , Íleon/microbiología , Heces/microbiología , Enfermedades Inflamatorias del Intestino/cirugía , Enfermedades Inflamatorias del Intestino/microbiología , Síndrome del Intestino Corto/cirugía , Síndrome del Intestino Corto/microbiología , Síndrome del Intestino Corto/metabolismo , Femenino , Masculino , Adulto , Persona de Mediana EdadRESUMEN
Functional dyspepsia (FD) affects up to 15% of the population and is characterised by recurring upper gastrointestinal (GI) symptoms occurring in the absence of clinically identifiable pathology. Psychological stress is a key factor associated with the onset of FD and locally acting hypothalamic-pituitary-adrenal (HPA) axis hormones have been implicated in GI motility and barrier dysfunction. Recent pre-clinical work has identified mechanistic pathways linking corticotropin-releasing hormone (CRH) with the innate epithelial immune protein NLRP6, an inflammasome that has been shown to regulate GI mucus secretion. We recruited twelve FD patients and twelve healthy individuals to examine whether dysregulation of hypothalamic-pituitary adrenal (HPA) axis hormones and altered NLRP6 pathways were evident in the duodenal mucosa. Protein expression was assessed by immunoblot and immunohistochemistry in D2 duodenal biopsies. Plasma HPA axis hormones were assayed by ELISA and enteroid and colorectal cancer cell line cultures were used to verify function. FD patients exhibited reduced duodenal CRH-receptor 2, compared to non-GI disease controls, indicating a dysregulation of duodenal HPA signalling. The loss of CRH-receptor 2 correlated with reduced NLRP6 expression and autophagy function, processes critical for maintaining goblet cell homeostasis. In accordance, duodenal goblet cell numbers and mucin exocytosis was reduced in FD patients compared to controls. In vitro studies demonstrated that CRH could reduce NLRP6 in duodenal spheroids and promote mucus secretion in the HT29-MTX-E12 cell line. In conclusion, FD patients exhibit defects in the NLRP6-autophagy axis with decreased goblet cell function that may drive symptoms of disease. These features correlated with loss of CRH receptor 2 and may be driven by dysregulation of HPA signalling in the duodenum of FD patients.
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Dispepsia , Péptidos y Proteínas de Señalización Intracelular , Sistema Hipófiso-Suprarrenal , Receptores de Hormona Liberadora de Corticotropina , Autofagia , Duodeno/metabolismo , Dispepsia/metabolismo , Células Caliciformes/metabolismo , Homeostasis , Hormonas/metabolismo , Humanos , Sistema Hipotálamo-Hipofisario/metabolismo , Péptidos y Proteínas de Señalización Intracelular/genética , Sistema Hipófiso-Suprarrenal/metabolismo , Receptores de Hormona Liberadora de Corticotropina/genética , Receptores de Hormona Liberadora de Corticotropina/metabolismoRESUMEN
Intestinal epithelia are critical for maintaining gastrointestinal homeostasis. Epithelial barrier injury, causing inflammation and vascular damage, results in inflammatory hypoxia, and thus, healing occurs in an oxygen-restricted environment. The transcription factor hypoxia-inducible factor (HIF)-1 regulates genes important for cell survival and repair, including the cell adhesion protein ß1-integrin. Integrins function as αß-dimers, and α-integrin-matrix binding is critical for cell migration. We hypothesized that HIF-1 stabilization accelerates epithelial migration through integrin-dependent pathways. We aimed to examine functional and posttranslational activity of α-integrins during HIF-1-mediated intestinal epithelial healing. Wound healing was assessed in T84 monolayers over 24 h with/without prolyl-hydroxylase inhibitor (PHDi) (GB-004), which stabilizes HIF-1. Gene and protein expression were measured by RT-PCR and immunoblot, and α-integrin localization was assessed by immunofluorescence. α-integrin function was assessed by antibody-mediated blockade, and integrin α6 regulation was determined by HIF-1α chromatin immunoprecipitation. Models of mucosal wounding and 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis were used to examine integrin expression and localization in vivo. PHDi treatment accelerated wound closure and migration within 12 h, associated with increased integrin α2 and α6 protein, but not α3. Functional blockade of integrins α2 and α6 inhibited PHDi-mediated accelerated wound closure. HIF-1 bound directly to the integrin α6 promoter. PHDi treatment accelerated mucosal healing, which was associated with increased α6 immunohistochemical staining in wound-associated epithelium and wound-adjacent tissue. PHDi treatment increased α6 protein levels in colonocytes of TNBS mice and induced α6 staining in regenerating crypts and reepithelialized inflammatory lesions. Together, these data demonstrate a role for HIF-1 in regulating both integrin α2 and α6 responses during intestinal epithelial healing.NEW & NOTEWORTHY HIF-1 plays an important role in epithelial restitution, selectively inducing integrins α6 and α2 to promote migration and proliferation, respectively. HIF-stabilizing prolyl-hydroxylase inhibitors accelerate intestinal mucosal healing by inducing epithelial integrin expression.
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Colitis/prevención & control , Colon/efectos de los fármacos , Subunidad alfa del Factor 1 Inducible por Hipoxia/metabolismo , Cadenas alfa de Integrinas/metabolismo , Mucosa Intestinal/efectos de los fármacos , Inhibidores de Prolil-Hidroxilasa/farmacología , Cicatrización de Heridas/efectos de los fármacos , Animales , Línea Celular Tumoral , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Colitis/inducido químicamente , Colitis/metabolismo , Colitis/patología , Colon/metabolismo , Colon/patología , Modelos Animales de Enfermedad , Femenino , Humanos , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Cadenas alfa de Integrinas/genética , Integrina alfa2/metabolismo , Integrina alfa6/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Ratones Endogámicos BALB C , Estabilidad Proteica , Transducción de Señal , Ácido TrinitrobencenosulfónicoRESUMEN
Liver inflammation is a common extraintestinal manifestation in inflammatory bowel disease (IBD), yet, the mechanisms driving gut-liver axis inflammation remain poorly understood. IBD leads to a breakdown in the integrity of the intestinal barrier causing an increase in portal and systemic gut-derived antigens, which challenge the liver. Here, we examined the role of platelet activating factor receptor (PAFR) in colitis-associated liver damage using dextran sulfate sodium (DSS) and anti-CD40-induced colitis models. Both DSS and anti-CD40 models exhibited liver inflammation associated with colitis. Colitis reduced global PAFR protein expression in mouse livers causing an exclusive re-localization of PAFR to the portal triad. The global decrease in liver PAFR was associated with increased sirtuin 1 while relocalized PAFR expression was limited to Kupffer cells (KCs) and co-localized with toll-like receptor 4. DSS activated the NLRP3-inflammasome and increased interleukin (IL)-1ß in the liver. Antagonism of PAFR amplified the inflammasome response by increasing NLRP3, caspase-1, and IL-1ß protein levels in the liver. LPS also increased NLRP3 response in human hepatocytes, however, overexpression of PAFR restored the levels of NLPR3 and caspase-1 proteins. Interestingly, KCs depletion also increased IL-1ß protein in mouse liver after DSS challenge. These data suggest a protective role for PAFR-expressing KCs during colitis and that regulation of PAFR is important for gut-liver axis homeostasis.
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Colitis/metabolismo , Colitis/patología , Inflamación/metabolismo , Inflamación/patología , Hígado/metabolismo , Glicoproteínas de Membrana Plaquetaria/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animales , Caspasa 1/metabolismo , Células Cultivadas , Colitis/inducido químicamente , Colon/metabolismo , Colon/patología , Sulfato de Dextran/farmacología , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Hepatocitos/patología , Humanos , Inflamasomas/metabolismo , Inflamación/inducido químicamente , Enfermedades Inflamatorias del Intestino/metabolismo , Enfermedades Inflamatorias del Intestino/patología , Interleucina-1beta/metabolismo , Macrófagos del Hígado/metabolismo , Macrófagos del Hígado/patología , Hígado/efectos de los fármacos , Hígado/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Receptor Toll-Like 4/metabolismoRESUMEN
BACKGROUND: Glutathione S-transferases omega class 1 (GSTO1-1) is a unique member of the GST family regulating cellular redox metabolism and innate immunity through the promotion of LPS/TLR4/NLRP3 signalling in macrophages. House dust mite (HDM) triggers asthma by promoting type 2 responses and allergic inflammation via the TLR4 pathway. Although linked to asthma, the role of GSTO1-1 in facilitating type 2 responses and/or HDM-driven allergic inflammation is unknown. OBJECTIVE: To determine the role of GSTO1-1 in regulating HDM-induced allergic inflammation in a preclinical model of asthma. METHODS: Wild-type and GSTO1-1-deficient mice were sensitized and aeroallergen challenged with HDM to induce allergic inflammation and subsequently hallmark pathophysiological features characterized. RESULTS: By contrast to HDM-challenged WT mice, exposed GSTO1-1-deficient mice had increased numbers of eosinophils and macrophages and elevated levels of eotaxin-1 and -2 in their lungs. M1 macrophage-associated factors, such as IL-1ß and IL-6, were decreased in GSTO1-1-deficient mice. Conversely, M2 macrophage factors such as Arg-1 and Ym1 were up-regulated. HIF-1α expression was found to be higher in the absence of GSTO1-1 and correlated with the up-regulation of M2 macrophage markers. Furthermore, HIF-1α was shown to bind and activate the eotaxin-2 promotor. Hypoxic conditions induced significant increases in the levels of eotaxin-1 and -2 in GSTO1-deficient BMDMs, providing a potential link between inflammation-induced hypoxia and the regulation of M2 responses in the lung. Collectively, our results suggest that GSTO1-1 deficiency promotes M2-type responses and increased levels of nuclear HIF-1α, which regulates eotaxin (s)-induced eosinophilia and increased disease severity. CONCLUSION & CLINICAL IMPLICATION: We propose that GSTO1-1 is a novel negative regulator of TLR4-regulated M2 responses acting as an anti-inflammatory pathway. The discovery of a novel HIF-1α-induced eotaxin pathway identifies an unknown connection between hypoxia and the regulation of the severity of allergic inflammation in asthma.
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Asma/inmunología , Proteínas Portadoras/inmunología , Eosinófilos/inmunología , Glutatión Transferasa/inmunología , Subunidad alfa del Factor 1 Inducible por Hipoxia/inmunología , Macrófagos/metabolismo , Animales , Asma/genética , Asma/patología , Proteínas Portadoras/genética , Eosinófilos/patología , Glutatión Transferasa/genética , Subunidad alfa del Factor 1 Inducible por Hipoxia/genética , Macrófagos/patología , Masculino , Ratones , Ratones NoqueadosRESUMEN
BACKGROUND: Anastomotic leak rates have not improved over several decades despite improvements in surgical techniques and patient care. The gut microbiome has been implicated in the development of leaks. The exact mechanisms by which tissue oxygenation affects gut microbial composition and anastomotic healing physiology are unclear. Also, commonly used carbon dioxide (CO2) is a known vasodilator that improves tissue oxygen tension. We performed a systematic review to determine the influence of hyperoxia, hypoxia, and hypercapnia on the gut microbiome and anastomotic healing. METHODS: A literature search was performed in MEDLINE, EMBASE, and COCHRANE to identify studies investigating the effects of hyperoxia, hypoxia, and hypercapnia on anastomotic healing and gut microbiota published between 1998 and 2018. Two reviewers screened the articles for eligibility and quality. Fifty-three articles underwent full text review, and a narrative synthesis was undertaken. RESULTS: Hyperoxia is associated with better anastomotic healing, increased gastrointestinal oxygen tension, and may reduce gut anaerobes. Hypoxia is associated with poor healing and increased gut anaerobes. However, it is unclear if hypoxia is the most important predictor of anastomotic leaks. Low pressure CO2 pneumoperitoneum and mild systemic hypercapnia are both associated with increased gastrointestinal oxygen tension and may improve anastomotic healing. We found no studies which investigated the effect of hypercapnia on gut microbiota in the context of anastomotic healing. CONCLUSIONS: Tissue oxygenation influences gut anastomotic healing, but little evidence exists to demonstrate the influence on the gut microbiome in the context of healing. Further studies are needed to determine if anastomotic microbiome changes with altered tissue oxygenation and if this affects healing and leak rates. If confirmed, altering tissue oxygenation through hyperoxia or hypercapnia could be feasible means of altering the microbiome such that anastomotic leak rates reduce.
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Fuga Anastomótica/fisiopatología , Microbioma Gastrointestinal/fisiología , Hipercapnia/fisiopatología , Hiperoxia/fisiopatología , Hipoxia/fisiopatología , Mucosa Intestinal/cirugía , Anastomosis Quirúrgica/efectos adversos , Fuga Anastomótica/etiología , Fuga Anastomótica/microbiología , Animales , Modelos Animales de Enfermedad , Humanos , Hipercapnia/metabolismo , Hiperoxia/metabolismo , Hipoxia/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiología , Oxígeno/metabolismo , Cicatrización de Heridas/fisiologíaRESUMEN
Extra-intestinal manifestations (EIM) are common in inflammatory bowel disease (IBD). One such EIM is sub-clinical pulmonary inflammation, which occurs in up to 50% of IBD patients. In animal models of colitis, pulmonary inflammation is driven by neutrophilic infiltrations, primarily in response to the systemic bacteraemia and increased bacterial load in the lungs. Platelet activating factor receptor (PAFR) plays a critical role in regulating pulmonary responses to infection in conditions, such as chronic obstructive pulmonary disease and asthma. We investigated the role of PAFR in pulmonary EIMs of IBD, using dextran sulfate sodium (DSS) and anti-CD40 murine models of colitis. Both models induced neutrophilic inflammation, with increased TNF and IL-1ß levels, bacterial load and PAFR protein expression in mouse lungs. Antagonism of PAFR decreased lung neutrophilia, TNF, and IL-1ß in an NLRP3 inflammasome-dependent manner. Lipopolysaccharide from phosphorylcholine (ChoP)-positive bacteria induced NLRP3 and caspase-1 proteins in human alveolar epithelial cells, however antagonism of PAFR prevented NLRP3 activation by ChoP. Amoxicillin reduced bacterial populations in the lungs and reduced NLRP3 inflammasome protein levels, but did not reduce PAFR. These data suggest a role for PAFR in microbial pattern recognition and NLRP3 inflammasome signaling in the lung.
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Colitis/complicaciones , Susceptibilidad a Enfermedades , Proteína con Dominio Pirina 3 de la Familia NLR/metabolismo , Glicoproteínas de Membrana Plaquetaria/metabolismo , Neumonía/etiología , Neumonía/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Animales , Biopsia , Sulfato de Dextran/efectos adversos , Modelos Animales de Enfermedad , Endoscopía , Inmunohistoquímica , Inflamasomas/metabolismo , Enfermedades Inflamatorias del Intestino/complicaciones , Ratones , Infiltración Neutrófila/inmunología , Neumonía/patología , Transducción de SeñalRESUMEN
There is a major unmet clinical need to identify pathways in inflammatory bowel disease (IBD) to classify patient disease activity, stratify patients that will benefit from targeted therapies such as anti-tumor necrosis factor (TNF), and identify new therapeutic targets. In this study, we conducted global transcriptome analysis to identify IBD-related pathways using colon biopsies, which highlighted the coagulation gene pathway as one of the most enriched gene sets in patients with IBD. Using this gene-network analysis across 14 independent cohorts and 1800 intestinal biopsies, we found that, among the coagulation pathway genes, plasminogen activator inhibitor-1 (PAI-1) expression was highly enriched in active disease and in patients with IBD who did not respond to anti-TNF biologic therapy and that PAI-1 is a key link between the epithelium and inflammation. Functionally, PAI-1 and its direct target, the fibrinolytic protease tissue plasminogen activator (tPA), played an important role in regulating intestinal inflammation. Intestinal epithelial cells produced tPA, which was protective against chemical and mechanical-mediated colonic injury in mice. In contrast, PAI-1 exacerbated mucosal damage by blocking tPA-mediated cleavage and activation of anti-inflammatory TGF-ß, whereas the inhibition of PAI-1 reduced both mucosal damage and inflammation. This study identifies an immune-coagulation gene axis in IBD where elevated PAI-1 may contribute to more aggressive disease.
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Colitis/metabolismo , Colitis/patología , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Inhibidor 1 de Activador Plasminogénico/metabolismo , Animales , Factores Biológicos/farmacología , Factores Biológicos/uso terapéutico , Coagulación Sanguínea , Proliferación Celular/efectos de los fármacos , Citrobacter/efectos de los fármacos , Colitis/inmunología , Colitis/microbiología , Colon/patología , Citocinas/metabolismo , Inflamación/patología , Enfermedades Inflamatorias del Intestino/sangre , Enfermedades Inflamatorias del Intestino/tratamiento farmacológico , Enfermedades Inflamatorias del Intestino/patología , Interleucina-17/metabolismo , Ratones , Índice de Severidad de la Enfermedad , Bibliotecas de Moléculas Pequeñas/farmacología , Células Th17/inmunología , Activador de Tejido Plasminógeno/metabolismo , Transcripción Genética , Factor de Crecimiento Transformador beta/metabolismoRESUMEN
Inflammatory bowel disease (IBD) is associated with several immune-mediated extraintestinal manifestations. More than half of all IBD patients have some form of respiratory pathology, most commonly neutrophil-mediated diseases, such as bronchiectasis and chronic bronchitis. Using murine models of colitis, we aimed to identify the immune mechanisms driving pulmonary manifestations of IBD. We found increased neutrophil numbers in lung tissue associated with the pulmonary vasculature in both trinitrobenzenesulfonic acid- and dextran sulfate sodium-induced models of colitis. Analysis of systemic inflammation identified that neutrophilia was associated with bacteremia and pyrexia in animal models of colitis. We further identified IL-6 as a systemic mediator of neutrophil recruitment from the bone marrow of dextran sulfate sodium animals. Functional inhibition of IL-6 led to reduced systemic and pulmonary neutrophilia, but it did not attenuate established colitis pathology. These data suggest that systemic bacteremia and pyrexia drive IL-6 secretion, which is a critical driver for pulmonary manifestation of IBD. Targeting IL-6 may reduce neutrophil-associated extraintestinal manifestations in IBD patients.
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Bacteriemia/patología , Colitis/complicaciones , Modelos Animales de Enfermedad , Interleucina-6/toxicidad , Neutrófilos/inmunología , Neumonía/patología , Animales , Bacteriemia/etiología , Bacteriemia/metabolismo , Colitis/inducido químicamente , Sulfato de Dextran/toxicidad , Femenino , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Neutrófilos/efectos de los fármacos , Neutrófilos/patología , Neumonía/etiología , Neumonía/metabolismoRESUMEN
Crohn's disease (CD) is a chronic inflammatory disease of the gastrointestinal tract (GIT). Cigarette smoke (CS) exposure and chronic obstructive pulmonary disease (COPD) are risk factors for CD, although the mechanisms involved are poorly understood. We employed a mouse model of CS-induced experimental COPD and clinical studies to examine these mechanisms. Concurrent with the development of pulmonary pathology and impaired gas exchange, CS-exposed mice developed CD-associated pathology in the colon and ileum, including gut mucosal tissue hypoxia, HIF-2 stabilization, inflammation, increased microvasculature, epithelial cell turnover, and decreased intestinal barrier function. Subsequent smoking cessation reduced GIT pathology, particularly in the ileum. Dimethyloxaloylglycine, a pan-prolyl hydroxylase inhibitor, ameliorated CS-induced GIT pathology independently of pulmonary pathology. Prior smoke exposure exacerbated intestinal pathology in 2,4,6-trinitrobenzenesulfonic acid-induced (TNBS-induced) colitis. Circulating vascular endothelial growth factor, a marker of systemic hypoxia, correlated with CS exposure and CD in mice and humans. Increased mucosal vascularisation was evident in ileum biopsies from CD patients who smoke compared with nonsmokers, supporting our preclinical data. We provide strong evidence that chronic CS exposure and, for the first time to our knowledge, associated impaired gas exchange cause systemic and intestinal ischemia, driving angiogenesis and GIT epithelial barrier dysfunction, resulting in increased risk and severity of CD.
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Enfermedad de Crohn/patología , Nicotiana/efectos adversos , Enfermedad Pulmonar Obstructiva Crónica/patología , Humo/efectos adversos , Fumar/efectos adversos , Adulto , Anciano , Aminoácidos Dicarboxílicos/administración & dosificación , Animales , Biopsia , Hipoxia de la Célula/efectos de los fármacos , Colon/diagnóstico por imagen , Colon/efectos de los fármacos , Colon/patología , Colonoscopía , Enfermedad de Crohn/diagnóstico por imagen , Enfermedad de Crohn/etiología , Modelos Animales de Enfermedad , Progresión de la Enfermedad , Femenino , Humanos , Íleon/diagnóstico por imagen , Íleon/efectos de los fármacos , Íleon/patología , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/patología , Pulmón/efectos de los fármacos , Pulmón/patología , Masculino , Ratones , Ratones Endogámicos C57BL , Persona de Mediana Edad , Estrés Oxidativo/efectos de los fármacos , Prolil Hidroxilasas/metabolismo , Inhibidores de Prolil-Hidroxilasa/administración & dosificación , Enfermedad Pulmonar Obstructiva Crónica/etiología , Intercambio Gaseoso Pulmonar/efectos de los fármacos , Factores de Riesgo , Cese del Hábito de Fumar , Factores de Tiempo , Ácido Trinitrobencenosulfónico/toxicidadRESUMEN
The intestinal epithelium constitutes an innate barrier which, upon injury, undergoes self-repair processes known as restitution. Although bile acids are known as important regulators of epithelial function in health and disease, their effects on wound healing processes are not yet clear. Here we set out to investigate the effects of the colonic bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on epithelial restitution. Wound healing in T84 cell monolayers grown on transparent, permeable supports was assessed over 48 h with or without bile acids. Cell migration was measured in Boyden chambers. mRNA and protein expression were measured by RT-PCR and Western blotting. DCA (50-150 µM) significantly inhibited wound closure in cultured epithelial monolayers and attenuated cell migration in Boyden chamber assays. DCA also induced nuclear accumulation of the farnesoid X receptor (FXR), whereas an FXR agonist, GW4064 (10 µM), inhibited wound closure. Both DCA and GW4064 attenuated the expression of CFTR Cl- channels, whereas inhibition of CFTR activity with either CFTR-inh-172 (10 µM) or GlyH-101 (25 µM) also prevented wound healing. Promoter/reporter assays revealed that FXR-induced downregulation of CFTR is mediated at the transcriptional level. In contrast, UDCA (50-150 µM) enhanced wound healing in vitro and prevented the effects of DCA. Finally, DCA inhibited and UDCA promoted mucosal healing in an in vivo mouse model. In conclusion, these studies suggest bile acids are important regulators of epithelial wound healing and are therefore good targets for development of new drugs to modulate intestinal barrier function in disease treatment. NEW & NOTEWORTHY The secondary bile acid, deoxycholic acid, inhibits colonic epithelial wound healing, an effect which appears to be mediated by activation of the nuclear bile acid receptor, FXR, with subsequent downregulation of CFTR expression and activity. In contrast, ursodeoxycholic acid promotes wound healing, suggesting it may provide an alternative approach to prevent the losses of barrier function that are associated with mucosal inflammation in IBD patients.
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Colon/efectos de los fármacos , Ácido Desoxicólico/farmacología , Mucosa Intestinal/efectos de los fármacos , Ácido Ursodesoxicólico/farmacología , Cicatrización de Heridas/efectos de los fármacos , Animales , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Colon/metabolismo , Colon/patología , Regulador de Conductancia de Transmembrana de Fibrosis Quística/genética , Regulador de Conductancia de Transmembrana de Fibrosis Quística/metabolismo , Femenino , Células HEK293 , Humanos , Mucosa Intestinal/metabolismo , Mucosa Intestinal/patología , Ratones Endogámicos C57BL , Regiones Promotoras Genéticas , Receptores Citoplasmáticos y Nucleares/genética , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores X Retinoide/genética , Receptores X Retinoide/metabolismo , Transducción de Señal/efectos de los fármacos , Transcripción Genética/efectos de los fármacosRESUMEN
BACKGROUND: Pharmacological induction of hypoxia-inducible factor (HIF), a global transcriptional regulator of the hypoxic response, by prolyl hydroxylase inhibitors (PHDi) is protective in murine models of colitis, and epithelial cells are critical for the observed therapeutic efficacy. Because systemic HIF activation may lead to potentially negative off-target effects, we hypothesized that targeting epithelial HIF through oral delivery of PHDi would be sufficient to protect against colitis in a mouse model. METHODS: Using a chemically induced trinitrobenzene sulfonic acid murine model of colitis, we compared the efficacy of oral and intraperitoneal (i.p.) delivery of the PHDi; AKB-4924 in preventing colitis, as measured by endoscopy, histology, barrier integrity, and immune profiling. Furthermore, we measured potential off-target effects, examining HIF and HIF target genes in the heart and kidney, as well as erythropoietin and hematocrit levels. RESULTS: Oral administration of AKB-4924 exhibited mucosal protection comparable i.p. dosing. Oral delivery of PHDi led to reduced colonic epithelial HIF stabilization compared with i.p. delivery, but this was still sufficient to induce transcription of downstream HIF targets. Furthermore, oral delivery of PHDi led to reduced stabilization of HIF and activation of HIF targets in extraintestinal organs. CONCLUSIONS: Oral delivery of PHDi therapies to this intestinal mucosa protects against colitis in animal models and represents a potential therapeutic strategy for inflammatory bowel disease, which also precludes unwanted extraintestinal effects.
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Colitis/tratamiento farmacológico , Modelos Animales de Enfermedad , Membrana Mucosa/efectos de los fármacos , Piperazinas/administración & dosificación , Inhibidores de Prolil-Hidroxilasa/administración & dosificación , Piridonas/administración & dosificación , Cicatrización de Heridas/efectos de los fármacos , Administración Oral , Animales , Colitis/inducido químicamente , Colitis/patología , Femenino , Factor 1 Inducible por Hipoxia/agonistas , Factor 1 Inducible por Hipoxia/metabolismo , Técnicas para Inmunoenzimas , Mucosa Intestinal/citología , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/metabolismo , Ratones , Ratones Endogámicos BALB C , Membrana Mucosa/metabolismo , Piperazinas/farmacología , Inhibidores de Prolil-Hidroxilasa/farmacología , Piridonas/farmacología , Ácido Trinitrobencenosulfónico/toxicidadRESUMEN
Epithelial damage and loss of intestinal barrier function are hallmark pathologies of the mucosal inflammation associated with conditions such as inflammatory bowel disease. In order to resolve inflammation and restore intestinal integrity the mucosa must rapidly and effectively repair the epithelial barrier. Epithelial wound healing is a highly complex and co-ordinated process and the factors involved in initiating intestinal epithelial healing are poorly defined. In order for restitution to be successful there must be a balance between epithelial cell migration, proliferation, and differentiation within and adjacent to the inflamed area. Endogenous, compensatory epithelial signaling pathways are activated by the changes in oxygen tensions that accompany inflammation. These signaling pathways induce the activation of key transcription factors, governing anti-apoptotic, and proliferative processes resulting in epithelial cell survival, proliferation, and differentiation at the site of mucosal inflammation. In this review, we will discuss the primary processes involved in epithelial restitution with a focus on the role of hypoxia-inducible factor and epithelial integrins as mediators of epithelial repair following inflammatory injury at the mucosal surface.