RESUMEN
The colonic epithelium can undergo multiple rounds of damage and repair, often in response to excessive inflammation. The responsive stem cell that mediates this process is unclear, in part because of a lack of in vitro models that recapitulate key epithelial changes that occur in vivo during damage and repair. Here, we identify a Hopx+ colitis-associated regenerative stem cell (CARSC) population that functionally contributes to mucosal repair in mouse models of colitis. Hopx+ CARSCs, enriched for fetal-like markers, transiently arose from hypertrophic crypts known to facilitate regeneration. Importantly, we established a long-term, self-organizing two-dimensional (2D) epithelial monolayer system to model the regenerative properties and responses of Hopx+ CARSCs. This system can reenact the "homeostasis-injury-regeneration" cycles of epithelial alterations that occur in vivo. Using this system, we found that hypoxia and endoplasmic reticulum stress, insults commonly present in inflammatory bowel diseases, mediated the cyclic switch of cellular status in this process.
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Técnicas de Cultivo de Célula/métodos , Colon/patología , Células Madre/patología , Células 3T3 , Animales , Colitis/patología , Células Epiteliales/efectos de los fármacos , Células Epiteliales/patología , Proteínas de Homeodominio/metabolismo , Ratones , Modelos Biológicos , Oxígeno/farmacología , Regeneración/efectos de los fármacos , Células Madre/efectos de los fármacos , Estrés Fisiológico/efectos de los fármacosRESUMEN
The gut microbiota has been shown critical for mucosal adjuvant activity of cholera toxin (CT), a potent mucosal adjuvant. However, the mechanisms involved remain largely unknown. In this study, we report that depletion of gut bacteria significantly decreased mucosal and systemic Ab responses in mice orally immunized with OVA and CT. Feeding mice short-chain fatty acids (SCFAs) promoted Ab responses elicited by CT, and, more importantly, rescued Ab responses in antibiotic-treated mice. In addition, mice deficient in GPR43, a receptor for SCFAs, showed impaired adjuvant activity of CT. Administering CT did not promote SCFA production in the intestines; thus, SCFAs facilitated but did not directly mediate the adjuvant activity of CT. SCFAs promoted B cell Ab production by promoting dendritic cell production of BAFF and ALDH1a2, which induced B cell expression of IFN regulatory factor 4, Blimp1, and XBP1, the plasma B cell differentiation-related genes. Furthermore, when infected with Citrobacter rodentium, GPR43-/- mice exhibited decreased Ab responses and were more susceptible to infection, whereas the administration of SCFAs promoted intestinal Ab responses in wild-type mice. Our study thereby demonstrated a critical role of gut microbiota and their metabolite SCFAs in promoting mucosal adjuvant activity of CT through GPR43.
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Adyuvantes Inmunológicos/metabolismo , Linfocitos B/inmunología , Toxina del Cólera/metabolismo , Citrobacter rodentium/fisiología , Células Dendríticas/inmunología , Infecciones por Enterobacteriaceae/inmunología , Ácidos Grasos Volátiles/metabolismo , Microbioma Gastrointestinal/fisiología , Receptores Acoplados a Proteínas G/metabolismo , Familia de Aldehído Deshidrogenasa 1/metabolismo , Animales , Formación de Anticuerpos , Factor Activador de Células B/metabolismo , Diferenciación Celular , Inmunidad Mucosa , Ratones , Ratones Noqueados , Comunicación Paracrina , Receptores Acoplados a Proteínas G/genética , Retinal-Deshidrogenasa/metabolismoRESUMEN
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.
Asunto(s)
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
BACKGROUND & AIMS: Regenerating islet-derived protein (REG3γ), an antimicrobial peptide, typically expressed by intestinal epithelial cells (IEC), plays crucial roles in intestinal homeostasis and controlling gut microbiota. However, the mechanisms that regulate IEC expression of REG3γ are still largely unclear. In this study, we investigated whether and how interleukin (IL) 33, an alarmin produced by IEC in response to injury, regulates REG3γ expression in IEC, thus contributing to intestinal homeostasis. METHODS: IEC were isolated from wild-type and IL33-/- mice to determine expression of REG3γ and other antimicrobial peptides by quantitative real-time polymerase chain reaction and Western blot. IEC cell lines were used for mechanistic studies. 16S rRNA pyrosequencing analysis was used for measuring gut microbiota. Citrobacter rodentium was used for enteric infections. RESULTS: The expression of REG3γ, but not ß-defensins, in IECs of IL33-/- mice was significantly lower than wild-type mice. IL33 treatment induced IEC expression of REG3γ in both mice and human cell lines. Mechanistically, IL33 activated STAT3, mTOR, and ERK1/2 in IEC. Inhibition of these pathways abrogated IL33-induction of REG3γ. IL33-/- mice demonstrated higher bacteria loads and altered microbiota composition. IL33 did not directly inhibit bacterial growth, but promoted wild-type, not REG3γKO, IECs to kill bacteria in vitro. Consistently, C rodentium infection induced IEC IL33 expression, and IL33-/- mice demonstrated an impaired bacterial clearance with C rodentium infection. CONCLUSIONS: Our study demonstrated that IL33, which is produced by IEC in response to injury and inflammatory stimulation, in turn promotes IEC expression of REG3γ, and controls the gut microbiota of the host.
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Bacterias/clasificación , Interleucina-33/metabolismo , Mucosa Intestinal/metabolismo , Proteínas Asociadas a Pancreatitis/metabolismo , ARN Ribosómico 16S/genética , Animales , Bacterias/genética , Bacterias/aislamiento & purificación , Células Cultivadas , Citrobacter rodentium/inmunología , Citrobacter rodentium/patogenicidad , Células Epiteliales/citología , Células Epiteliales/metabolismo , Microbioma Gastrointestinal , Regulación de la Expresión Génica , Células HT29 , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Mucosa Intestinal/citología , Ratones , Filogenia , Transducción de SeñalRESUMEN
Numerous scientific disciplines, including immunology, are now positioned to fully realize the potential of the intestinal microbiome to modulate a wide array of basic processes. Increasingly, microbiota-derived metabolites are being recognized for mediating these effects. Coupled with advances in large scale sequencing and mass spectrometry, research into the microbiota and their metabolites has entered into an era of rapid discovery. Here, we review recent studies that have shown how-specific metabolic products of the microbiome alter properties of the innate immune system that in turn modulate response to infection and immunity.
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Microbioma Gastrointestinal/inmunología , Sistema Inmunológico , Inmunidad Innata , Infecciones/inmunología , Animales , Homeostasis , Humanos , InmunomodulaciónRESUMEN
The role of retinoid-related orphan receptor γ t (RORγt) in Th17 cell differentiation has been well established; however, how it regulates other T cell lineages is still not clearly understood. In this study, we report that in mice, while promoting Th17 cell differentiation, RORγt inhibited IL-10 production by T cells, thereby preserving the pathogenicity of Th17 cells. Treatment with RORγt-specific inhibitor suppressed Th17 cell signature cytokines, but promoted IL-10 production. RORγt inhibitor-treated Th17 cells induce less severe colitis compared with control Th17 cells. Mechanistically, the RORγt inhibitor induced T cell expression of Blimp-1 (encoded by Prdm1). Prdm1-/- T cells produced significantly fewer IL-10 when treated with RORγt inhibitor compared with wild-type T cells. Furthermore, RORγt inhibitor-treated Prdm1-/- Th17 cells induce more severe colitis compared with RORγt inhibitor-treated wild-type Th17 cells. Collectively, our studies reveal a novel mechanism by which RORγt drives and maintains pathogenic Th17 cell development by inhibiting IL-10 production.
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Colitis/inmunología , Interleucina-10/metabolismo , Intestinos/inmunología , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/metabolismo , Células Th17/inmunología , Animales , Diferenciación Celular , Linaje de la Célula , Células Cultivadas , Represión Epigenética , Activación de Linfocitos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Factor 1 de Unión al Dominio 1 de Regulación Positiva/genéticaRESUMEN
T-cells are crucial in maintanence of intestinal homeostasis, however, it is still unclear how microbiota metabolites regulate T-effector cells. Here we show gut microbiota-derived short-chain fatty acids (SCFAs) promote microbiota antigen-specific Th1 cell IL-10 production, mediated by G-protein coupled receptors 43 (GPR43). Microbiota antigen-specific Gpr43-/- CBir1 transgenic (Tg) Th1 cells, specific for microbiota antigen CBir1 flagellin, induce more severe colitis compared with wide type (WT) CBir1 Tg Th1 cells in Rag-/- recipient mice. Treatment with SCFAs limits colitis induction by promoting IL-10 production, and administration of anti-IL-10R antibody promotes colitis development. Mechanistically, SCFAs activate Th1 cell STAT3 and mTOR, and consequently upregulate transcription factor B lymphocyte-induced maturation protein 1 (Blimp-1), which mediates SCFA-induction of IL-10. SCFA-treated Blimp1-/- Th1 cells produce less IL-10 and induce more severe colitis compared to SCFA-treated WT Th1 cells. Our studies, thus, provide insight into how microbiota metabolites regulate Th1 cell functions to maintain intestinal homeostasis.
Asunto(s)
Colitis/inmunología , Ácidos Grasos Volátiles/inmunología , Microbioma Gastrointestinal/inmunología , Interleucina-10/inmunología , Receptores Acoplados a Proteínas G/inmunología , Células TH1/inmunología , Animales , Ácidos Grasos Volátiles/metabolismo , Flagelina/inmunología , Expresión Génica , Técnicas de Inactivación de Genes , Homeostasis , Ratones , Factor 1 de Unión al Dominio 1 de Regulación Positiva/genética , Receptores Acoplados a Proteínas G/genética , Factor de Transcripción STAT3/inmunología , Serina-Treonina Quinasas TOR/inmunología , Regulación hacia ArribaRESUMEN
Neutrophils are the first responders to sites of inflammation when the intestinal epithelial barrier is breached and the gut microbiota invade. Despite current efforts in understanding the role of neutrophils in intestinal homeostasis, the complex interactions between neutrophils and intestinal epithelial cells (IECs) is still not well characterized. In this study, we demonstrated that neutrophils enhanced production of amphiregulin (AREG), a member of the EGFR ligand family, by IECs, which promoted IEC barrier function and tissue repair. Depletion of neutrophils resulted in more severe colitis in mice because of decreased AREG production by IECs upon dextran sodium sulfate (DSS) insult. Administration of AREG restored epithelial barrier function and ameliorated colitis. Furthermore, neutrophil-derived TGF-ß promoted AREG production by IECs. Mechanistically, TGF-ß activated MEK1/2 signaling, and inhibition of MEK1/2 abrogated TGF-ß-induced AREG production by IECs. Collectively, these findings reveal that neutrophils play an important role in the maintenance of IEC barrier function and homeostasis.
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Anfirregulina/metabolismo , Colitis/inmunología , Enfermedades Inflamatorias del Intestino/inmunología , Mucosa Intestinal/fisiología , Neutrófilos/fisiología , Factor de Crecimiento Transformador beta/metabolismo , Animales , Células Cultivadas , Colitis/inducido químicamente , Sulfato de Dextran , Modelos Animales de Enfermedad , Femenino , Homeostasis , Humanos , MAP Quinasa Quinasa 1/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Transducción de SeñalRESUMEN
The antimicrobial peptides (AMP) produced by intestinal epithelial cells (IEC) play crucial roles in the regulation of intestinal homeostasis by controlling microbiota. Gut microbiota has been shown to promote IEC expression of RegIIIγ and certain defensins. However, the mechanisms involved are still not completely understood. In this report, we found that IEC expression levels of RegIIIγ and ß-defensins 1, 3, and 4 were lower in G protein-coupled receptor (GPR)43-/- mice compared to that of wild-type (WT) mice. Oral feeding with short-chain fatty acids (SCFA) promoted IEC production of RegIIIγ and defensins in mice. Furthermore, SCFA induced RegIIIγ and ß-defensins in intestinal epithelial enteroids generated from WT but not GPR43-/- mice. Mechanistically, SCFA activated mTOR and STAT3 in IEC, and knockdown of mTOR and STAT3 impaired SCFA induction of AMP production. Our studies thus demonstrated that microbiota metabolites SCFA promoted IEC RegIIIγ and ß-defensins in a GPR43-dependent manner. The data thereby provide a novel pathway by which microbiota regulates IEC expression of AMP and intestinal homeostasis.
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Microbioma Gastrointestinal/fisiología , Mucosa Intestinal/fisiología , Receptores Acoplados a Proteínas G/metabolismo , Animales , Antiinfecciosos/metabolismo , Ácidos Grasos Volátiles/metabolismo , Homeostasis , Inmunidad Innata , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas Asociadas a Pancreatitis/genética , Proteínas Asociadas a Pancreatitis/metabolismo , Receptores Acoplados a Proteínas G/genética , Factor de Transcripción STAT3/metabolismo , Serina-Treonina Quinasas TOR/metabolismo , beta-Defensinas/genética , beta-Defensinas/metabolismoRESUMEN
BACKGROUND: Neutrophils are accumulated in inflamed mucosa of IBD and play an important role in the pathogenesis. CD177 is expressed in neutrophils specifically and upregulated during inflammation. However, the role of CD177+ neutrophils in pathogenesis of IBD remains elusive. MATERIALS AND METHODS: Expression of CD177 was analysed in peripheral blood and intestinal mucosa from patients with IBD using quantitative RT-PCR, flow cytometry and immunohistochemistry. CD177+ and CD177- neutrophils were isolated to determine gene differences by RNA sequencing. Colitis was established in CD177-/- and wild-type mice in response to dextran sulfate sodium (DSS) insults to determine the role of CD177+ neutrophils in IBD. RESULTS: CD177+ neutrophils were markedly increased in peripheral blood and inflamed mucosa from patients with active IBD compared with healthy controls. RNA sequencing revealed that differential gene expression between CD177+ and CD177- neutrophils from patients with IBD was associated with response to bacterial defence, hydrogen peroxide and reactive oxygen species (ROS). CD177+ neutrophils produced lower levels of proinflammatory cytokines (ie, interferon-γ, interleukin (IL)-6, IL-17A), but higher levels of IL-22 and transforming growth factor-ß, and exhibited increased bactericidal activities (ie, ROS, antimicrobial peptides, neutrophil extracellular trap) compared with CD177- subset. CD177-/- mice developed more severe colitis on DSS insults compared with wild-type mice. Moreover, CD177 deficiency led to compromised intestinal barrier and impaired antibacterial immunity through decreased production of IL-22 by CD177- neutrophils. CONCLUSIONS: CD177+ neutrophils represent functionally activated population and play a protective role in IBD through increased bactericidal activity and IL-22 production. Targeting CD177+ neutrophils may be beneficial for treatment of IBD.
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Inmunidad Mucosa/inmunología , Enfermedades Inflamatorias del Intestino/inmunología , Mucosa Intestinal/metabolismo , Isoantígenos/metabolismo , Neutrófilos/metabolismo , Receptores de Superficie Celular/metabolismo , Adolescente , Adulto , Animales , Técnicas de Cultivo de Célula , Citocinas/metabolismo , Femenino , Citometría de Flujo , Proteínas Ligadas a GPI/metabolismo , Humanos , Inmunohistoquímica , Enfermedades Inflamatorias del Intestino/metabolismo , Mucosa Intestinal/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Transgénicos , Persona de Mediana Edad , Neutrófilos/inmunología , Reacción en Cadena en Tiempo Real de la Polimerasa , Adulto JovenRESUMEN
It has been shown recently that neutrophils are able to produce IL-22 and IL-17, which differentially regulate the pathogenesis of inflammatory bowel disease. However, it is still largely unknown how the neutrophil production of IL-22 and IL-17 is regulated, and their role in the pathogenesis of inflammatory bowel disease. In this study, we found that IL-23 promoted neutrophil production of IL-17 and IL-22. IL-23 stimulated the neutrophil expression of IL-23R as well as rorc and ahr. Retinoid acid receptor-related orphan receptor γ t and aryl-hydrocarbon receptor differentially regulated IL-23 induction of neutrophil IL-17 and IL-22. In addition, IL-23 induced the activation of mTOR in neutrophils. Blockade of the mTOR pathway inhibited IL-23-induced expression of rorc and ahr, as well as IL-17 and IL-22 production. By using a microbiota Ag-specific T cell-mediated colitis model, we demonstrated that depletion of neutrophils, as well as blockade of IL-22, resulted in a significant increase in the severity of colitis, thereby indicating a protective role of neutrophils and IL-22 in chronic colitis. Collectively, our data revealed that neutrophils negatively regulate microbiota Ag-specific T cell induction of colitis, and IL-23 induces neutrophil production of IL-22 and IL-17 through induction of rorc and ahr, which is mediated by the mTOR pathway.
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Interleucina-17/biosíntesis , Interleucina-23/metabolismo , Interleucinas/biosíntesis , Neutrófilos/metabolismo , Receptores de Interleucina/metabolismo , Serina-Treonina Quinasas TOR/genética , Animales , Ciego/patología , Diferenciación Celular , Colitis/inmunología , Colitis/patología , Colon/patología , Interleucina-23/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/genética , Miembro 3 del Grupo F de la Subfamilia 1 de Receptores Nucleares/metabolismo , Fosfatidilinositol 3-Quinasas/metabolismo , Receptores de Hidrocarburo de Aril/genética , Receptores de Hidrocarburo de Aril/metabolismo , Receptores de Interleucina/genética , Transducción de Señal , Células Th17/inmunología , Interleucina-22RESUMEN
Multiple mechanisms are involved in regulation of host response to microbiota to maintain the intestinal homeostasis. Th17 cells are enriched in the intestinal lamina propria under steady conditions. Many studies have demonstrated that microbiota-reactive Th17 cells in the intestines mediate the pathogenesis of inflammatory bowel diseases. However, clinical trials of anti-interleukin-17A or anti-interleukin-17RA antibodies in patients with Crohn's Disease show no improvement or even exacerbation of disease. Accumulating data has also indicated that Th17 cells may provide a protective effect as well to the intestines from inflammatory insults under homeostasis regulation, even under inflammatory conditions. Thus both proinflammatory and anti-inflammatory functions of intestinal Th17 cells have emerged under various conditions. In this review article, we will summarize recent progresses of Th17 cells in regulation of intestinal homeostasis and in the pathogenesis of inflammatory bowel diseases.
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Linfocitos T CD4-Positivos/inmunología , Microbioma Gastrointestinal/inmunología , Enfermedades Inflamatorias del Intestino/fisiopatología , Mucosa Intestinal/fisiología , Células Th17/fisiología , Animales , Transdiferenciación Celular , Homeostasis , Humanos , Inmunoglobulina A/metabolismo , Enfermedades Inflamatorias del Intestino/inmunología , Interleucina-17/metabolismo , Interleucinas/metabolismo , Mucosa Intestinal/inmunología , Células Th17/inmunología , Interleucina-22RESUMEN
Multiple mechanisms exist in regulation of host responses to massive challenges from microbiota to maintain immune homeostasis in the intestines. Among these is the enriched Th17 cells in the intestines, which regulates intestinal homeostasis through induction of antimicrobial peptides and secretory IgA among others. However, the means by which Th17 cells develop in response to microbiota is still not completely understood. Although both TLR5 and CD172α(+) lamina propria dendritic cells (LPDC) have been shown to promote Th17 cell development, it is still unclear whether TLR5 mediates the CD172α(+)LPDC induction of Th17 cells. By using a microbiota antigen-specific T cell reporter mouse system, we demonstrated that microbiota antigen-specific T cells developed into Th17 cells in the intestinal LP, but not in the spleen when transferred into TCRßxδ(-/-) mice. LPDCs expressed high levels of TLR5, and most CD172α(+)LPDCs also co-expressed TLR5. LPDCs produced high levels of IL-23, IL-6 and TGFß when stimulated with commensal flagellin and promoted Th17 cell development when cultured with full-length CBir1 flagellin but not CBir1 peptide. Wild-type CD172α(+), but not CD172α(-), LPDCs induced Th17 cells, whereas TLR5-deficient LPDC did not induce Th17 cells. Our data thereby demonstrated that TLR5 mediates CD172α(+)LPDC induction of Th17 cells in the intestines.
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Células Dendríticas/inmunología , Inmunidad Mucosa , Mucosa Intestinal/inmunología , Receptores Inmunológicos/inmunología , Células Th17/inmunología , Receptor Toll-Like 5/inmunología , Animales , Células Dendríticas/citología , Células Dendríticas/efectos de los fármacos , Flagelina/farmacología , Regulación de la Expresión Génica/inmunología , Homeostasis , Interleucina-23/genética , Interleucina-23/inmunología , Interleucina-6/genética , Interleucina-6/inmunología , Mucosa Intestinal/citología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Cultivo Primario de Células , Receptores de Antígenos de Linfocitos T alfa-beta/deficiencia , Receptores de Antígenos de Linfocitos T alfa-beta/genética , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Receptores de Antígenos de Linfocitos T gamma-delta/deficiencia , Receptores de Antígenos de Linfocitos T gamma-delta/genética , Receptores de Antígenos de Linfocitos T gamma-delta/inmunología , Receptores Inmunológicos/deficiencia , Receptores Inmunológicos/genética , Transducción de Señal , Células Th17/citología , Receptor Toll-Like 5/genética , Factor de Crecimiento Transformador beta/genética , Factor de Crecimiento Transformador beta/inmunologíaRESUMEN
It has been shown that while commensal bacteria promote Th1, Th17 and Treg cells in lamina propria (LP) in steady-state conditions, they suppress mucosal Th2 cells. However, it is still unclear whether there are specific commensal organisms down-regulating Th2 responses, and the mechanism involved. Here we demonstrate that commensal A4 bacteria, a member of the Lachnospiraceae family, which produce an immunodominant microbiota CBir1 antigen, inhibits LP Th2-cell development. When transferred into the intestines of RAG(-/-) mice, CBir1-specific T cells developed predominately towards Th1 cells and Th17 cells, but to a lesser extent into Th2 cells. The addition of A4 bacterial lysates to CD4(+) T-cell cultures inhibited production of IL-4. A4 bacteria stimulated dendritic cell production of TGF-ß, and blockade of TGF-ß abrogated A4 bacteria inhibition of Th2-cell development in vitro and in vivo. Collectively, our data show that A4 bacteria inhibit Th2-cell differentiation by inducing dendritic cell production of TGF-ß.
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Células Dendríticas/inmunología , Bacterias Grampositivas/inmunología , Membrana Mucosa/inmunología , Simbiosis , Células Th2/inmunología , Factor de Crecimiento Transformador beta/inmunología , Animales , Diferenciación Celular , Células Cultivadas , Bacterias Grampositivas/química , Interleucina-4/biosíntesis , Interleucina-4/inmunología , Activación de Linfocitos , Ratones , Membrana Mucosa/microbiología , Células TH1/inmunología , Células Th17/inmunología , Células Th2/fisiología , Factor de Crecimiento Transformador beta/biosíntesisRESUMEN
T cells reactive to microbiota regulate the pathogenesis of inflammatory bowel disease (IBD). As T cell trafficking to intestines is regulated through interactions between highly specific chemokine-chemokine receptors, efforts have been made to develop intestine-specific immunosuppression based on blocking these key processes. CCR9, a gut-trophic chemokine receptor expressed by lymphocytes and dendritic cells, has been implicated in the regulation of IBD through mediating recruitment of T cells to inflamed sites. However, the role of CCR9 in inducing and sustaining inflammation in the context of IBD is poorly understood. In this study, we demonstrate that CCR9 deficiency in effector T cells and Tregs does not affect the development of colitis in a microbiota antigen-specific, T cell-mediated model. However, Treg cells express higher levels of CCR9 compared to those in effector T cells. Interestingly, CCR9 inhibits Treg cell development, in that CCR9-/- mice demonstrate a high level of Foxp3+ Tregs, and ligation of CCR9 by its ligand CCL25 inhibits Treg cell differentiation in vitro. Collectively, our data indicate that in addition to acting as a gut-homing molecule, CCR9 signaling shapes immune responses by inhibiting Treg cell development.
Asunto(s)
Receptores CCR/fisiología , Linfocitos T Reguladores/citología , Animales , Colitis/fisiopatología , Ratones , Ratones Transgénicos , Receptores CCR/genéticaRESUMEN
OBJECTIVE: To investigate whether lithium modifies open-field and elevated plus maze behavior, and brain phospho-glycogen synthase kinase 3 (P-GSK3beta) expression in Fmr1 knockout mice. METHODS: One hundred and eighty FVB mice, including knockout and wild type, with an age of 30 days were used. An open-field and elevated plus maze was utilized to test behavior, while western blot was used to measure the P-GSK3beta expression. Six groups were formed: control (saline), lithium chloride 30, 60, 90, 120, and 200 mg/kg. The experiments were carried out in the Institute of Neuroscience, Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China between January and June 2012. RESULTS: Lithium significantly decreased total distance, crossing, central area time, and center entry in the open-field test (p<0.05), and significantly reduced open-arm tracking, open-arm entry, and open-arm time in the elevated plus maze (p<0.05) in knockout mice. In wild type mice, significant changes were observed in both behavior tests in some treatment groups. Lithium ameliorated P-GSK3beta expression in the hippocampus of all the treatment groups in knockout mice (p<0.05). However, lithium did not modify either GSK3beta expression in tissues of knockout mice, or P-GSK3beta or GSK3beta expression in tissues of wild type mice. CONCLUSION: Lithium ameliorated open-field and elevated plus maze behaviors of Fmr1 knockout mice. This effect may be related to its enhancement of P-GSK3beta expression. Our findings suggest that lithium might have a therapeutic effect in fragile X syndrome.