RESUMO
How group 3 innate lymphoid cells (ILC3s) regulate mucosal protection in the presence of T cells remains poorly understood. Here, we examined ILC3 function in intestinal immunity using ILC3-deficient mice that maintain endogenous T cells, T helper 17 (TH17) cells, and secondary lymphoid organs. ILC3s were dispensable for generation of TH17 and TH22 cell responses to commensal and pathogenic bacteria, and absence of ILC3s did not affect IL-22 production by CD4 T cells before or during infection. However, despite the presence of IL-22-producing T cells, ILC3s and ILC3-derived IL-22 were required for maintaining homeostatic functions of the intestinal epithelium. T cell-sufficient, ILC3-deficient mice were capable of pathogen clearance and survived infection with a low dose of Citrobacter rodentium. However, ILC3s promoted pathogen tolerance at early time points of infection by activating tissue-protective immune pathways. Consequently, ILC3s were indispensable for survival after high-dose infection. Our results demonstrate a context-dependent role for ILC3s in immune-sufficient animals and provide a blueprint for uncoupling of ILC3 and TH17 cell functions.
Assuntos
Citrobacter rodentium , Infecções por Enterobacteriaceae , Imunidade Inata , Mucosa Intestinal , Linfócitos , Camundongos Endogâmicos C57BL , Animais , Imunidade Inata/imunologia , Camundongos , Linfócitos/imunologia , Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Camundongos Knockout , Interleucina 22 , Imunidade nas Mucosas/imunologia , Células Th17/imunologiaRESUMO
Mucosal vaccination presents a promising complement to parenteral vaccination. Bacterium-like particles (BLPs), peptidoglycan structures prepared from lactic acid bacteria, are explored as potential nasal vaccine adjuvants for respiratory infections. To date, studies on BLP-adjuvanted nasal vaccines against intestinal infections have remained limited. In this study, we demonstrated the efficacy of intranasal BLP-adjuvanted vaccination in controlling intestinal infections using the Citrobacter rodentium (C. rodentium) model in C57BL/6 mice. Intranasal vaccination of Intimin, an adhesin critical for intimate bacterial adhesion to colonic epithelial cells, combined with BLP (BLP+I) elicited robust Intimin-specific intestinal secretory IgA production, reduced bacterial load in feces and almost completely inhibited colonic hyperplasia, a characteristic symptom of C. rodentium infection in mice. Conversely, parenteral vaccination with Alhydrogel-adjuvanted Intimin failed to induce intestinal Intimin-specific IgA production, resulting in poor protection against C. rodentium infection. This underscores the pivotal role of mucosal IgA responses elicited by intranasal immunization in its protective efficacy. As this study did not delineate the precise protective mechanism conferred by BLP+I intranasal immunization against C. rodentium infection, further elucidation of the mechanisms underlying intranasal BLP+I immunization is required.
Assuntos
Administração Intranasal , Vacinas Bacterianas , Citrobacter rodentium , Infecções por Enterobacteriaceae , Camundongos Endogâmicos C57BL , Animais , Camundongos , Citrobacter rodentium/imunologia , Citrobacter rodentium/patogenicidade , Infecções por Enterobacteriaceae/prevenção & controle , Infecções por Enterobacteriaceae/imunologia , Vacinas Bacterianas/imunologia , Vacinas Bacterianas/administração & dosagem , Anticorpos Antibacterianos/imunologia , Anticorpos Antibacterianos/sangue , Feminino , Adjuvantes Imunológicos/administração & dosagem , Adesinas Bacterianas/imunologia , Adjuvantes de Vacinas/administração & dosagem , Imunidade nas Mucosas , Imunoglobulina A Secretora/imunologia , Imunoglobulina A/imunologia , Modelos Animais de Doenças , Enteropatias/prevenção & controle , Enteropatias/imunologiaRESUMO
The mouse pathogen Citrobacter rodentium is utilized as a model organism for studying infections caused by the human pathogens enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) and to elucidate mechanisms of mucosal immunity. In response to C. rodentium infection, innate lymphoid cells and T cells secrete interleukin (IL)-22, a cytokine that promotes mucosal barrier function. IL-22 plays a pivotal role in enabling mice to survive and recover from C. rodentium infection, although the exact mechanisms involved remain incompletely understood. Here, we investigated whether particular components of the host response downstream of IL-22 contribute to the cytokine's protective effects during C. rodentium infection. In line with previous research, mice lacking the IL-22 gene (Il22-/- mice) were highly susceptible to C. rodentium infection. To elucidate the role of specific antimicrobial proteins modulated by IL-22, we infected the following knockout mice: S100A9-/- (calprotectin), Lcn2-/- (lipocalin-2), Reg3b-/- (Reg3ß), Reg3g-/- (Reg3γ), and C3-/- (C3). All knockout mice tested displayed a considerable level of resistance to C. rodentium infection, and none phenocopied the lethality observed in Il22-/- mice. By investigating another arm of the IL-22 response, we observed that C. rodentium-infected Il22-/- mice exhibited an overall decrease in gene expression related to intestinal barrier integrity as well as significantly elevated colonic inflammation, gut permeability, and pathogen levels in the spleen. Taken together, these results indicate that host resistance to lethal C. rodentium infection may depend on multiple antimicrobial responses acting in concert, or that other IL-22-regulated processes, such as tissue repair and maintenance of epithelial integrity, play crucial roles in host defense to attaching and effacing pathogens.
Assuntos
Citrobacter rodentium , Infecções por Enterobacteriaceae , Interleucina 22 , Animais , Camundongos , Citrobacter rodentium/imunologia , Modelos Animais de Doenças , Infecções por Enterobacteriaceae/imunologia , Infecções por Enterobacteriaceae/microbiologia , Interleucina 22/genética , Interleucina 22/metabolismo , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Associadas a Pancreatite/genética , Proteínas Associadas a Pancreatite/metabolismo , Proteínas Associadas a Pancreatite/imunologiaRESUMO
Group 3 innate lymphoid cells (ILC3) are the major subset of gut-resident ILC with essential roles in infections and tissue repair, but how they adapt to the gut environment to maintain tissue residency is unclear. We report that Tox2 is critical for gut ILC3 maintenance and function. Gut ILC3 highly expressed Tox2, and depletion of Tox2 markedly decreased ILC3 in gut but not at central sites, resulting in defective control of Citrobacter rodentium infection. Single-cell transcriptional profiling revealed decreased expression of Hexokinase-2 in Tox2-deficient gut ILC3. Consistent with the requirement for hexokinases in glycolysis, Tox2-/- ILC3 displayed decreased ability to utilize glycolysis for protein translation. Ectopic expression of Hexokinase-2 rescued Tox2-/- gut ILC3 defects. Hypoxia and interleukin (IL)-17A each induced Tox2 expression in ILC3, suggesting a mechanism by which ILC3 adjusts to fluctuating environments by programming glycolytic metabolism. Our results reveal the requirement for Tox2 to support the metabolic adaptation of ILC3 within the gastrointestinal tract.
Assuntos
Citrobacter rodentium , Infecções por Enterobacteriaceae , Glicólise , Proteínas HMGB , Imunidade Inata , Linfócitos , Camundongos Knockout , Animais , Camundongos , Adaptação Fisiológica/imunologia , Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Trato Gastrointestinal/imunologia , Trato Gastrointestinal/metabolismo , Hexoquinase/metabolismo , Hexoquinase/genética , Interleucina-17/metabolismo , Linfócitos/imunologia , Linfócitos/metabolismo , Camundongos Endogâmicos C57BL , Transativadores/metabolismo , Transativadores/genética , Proteínas HMGB/genética , Proteínas HMGB/imunologia , Proteínas HMGB/metabolismoRESUMO
Interleukin 22 (IL-22) has a non-redundant role in immune defence of the intestinal barrier1-3. T cells, but not innate lymphoid cells, have an indispensable role in sustaining the IL-22 signalling that is required for the protection of colonic crypts against invasion during infection by the enteropathogen Citrobacter rodentium4 (Cr). However, the intestinal epithelial cell (IEC) subsets targeted by T cell-derived IL-22, and how T cell-derived IL-22 sustains activation in IECs, remain undefined. Here we identify a subset of absorptive IECs in the mid-distal colon that are specifically targeted by Cr and are differentially responsive to IL-22 signalling. Major histocompatibility complex class II (MHCII) expression by these colonocytes was required to elicit sustained IL-22 signalling from Cr-specific T cells, which was required to restrain Cr invasion. Our findings explain the basis for the regionalization of the host response to Cr and demonstrate that epithelial cells must elicit MHCII-dependent help from IL-22-producing T cells to orchestrate immune protection in the intestine.
Assuntos
Citrobacter rodentium , Colo , Células Epiteliais , Mucosa Intestinal , Linfócitos T , Animais , Feminino , Masculino , Camundongos , Citrobacter rodentium/imunologia , Colo/citologia , Colo/imunologia , Colo/microbiologia , Infecções por Enterobacteriaceae/imunologia , Infecções por Enterobacteriaceae/microbiologia , Células Epiteliais/imunologia , Células Epiteliais/microbiologia , Células Epiteliais/metabolismo , Antígenos de Histocompatibilidade Classe II/imunologia , Antígenos de Histocompatibilidade Classe II/metabolismo , Interleucina 22/imunologia , Interleucina 22/metabolismo , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Mucosa Intestinal/citologia , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Transdução de Sinais/imunologia , Linfócitos T/imunologia , Linfócitos T/metabolismoRESUMO
Conventional dendritic cells (cDC) play key roles in immune induction, but what drives their heterogeneity and functional specialization is still ill-defined. Here we show that cDC-specific deletion of the transcriptional repressor Bcl6 in mice alters the phenotype and transcriptome of cDC1 and cDC2, while their lineage identity is preserved. Bcl6-deficient cDC1 are diminished in the periphery but maintain their ability to cross-present antigen to CD8+ T cells, confirming general maintenance of this subset. Surprisingly, the absence of Bcl6 in cDC causes a complete loss of Notch2-dependent cDC2 in the spleen and intestinal lamina propria. DC-targeted Bcl6-deficient mice induced fewer T follicular helper cells despite a profound impact on T follicular regulatory cells in response to immunization and mounted diminished Th17 immunity to Citrobacter rodentium in the colon. Our findings establish Bcl6 as an essential transcription factor for subsets of cDC and add to our understanding of the transcriptional landscape underlying cDC heterogeneity.
Assuntos
Citrobacter rodentium , Células Dendríticas , Proteínas Proto-Oncogênicas c-bcl-6 , Células Th17 , Animais , Proteínas Proto-Oncogênicas c-bcl-6/genética , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Células Th17/imunologia , Células Th17/metabolismo , Camundongos , Citrobacter rodentium/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Células T Auxiliares Foliculares/imunologia , Células T Auxiliares Foliculares/metabolismo , Linfócitos T CD8-Positivos/imunologia , Deleção de Genes , Baço/imunologia , Baço/citologia , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismoRESUMO
Increased levels of proteases, such as trypsin, in the distal intestine have been implicated in intestinal pathological conditions1-3. However, the players and mechanisms that underlie protease regulation in the intestinal lumen have remained unclear. Here we show that Paraprevotella strains isolated from the faecal microbiome of healthy human donors are potent trypsin-degrading commensals. Mechanistically, Paraprevotella recruit trypsin to the bacterial surface through type IX secretion system-dependent polysaccharide-anchoring proteins to promote trypsin autolysis. Paraprevotella colonization protects IgA from trypsin degradation and enhances the effectiveness of oral vaccines against Citrobacter rodentium. Moreover, Paraprevotella colonization inhibits lethal infection with murine hepatitis virus-2, a mouse coronavirus that is dependent on trypsin and trypsin-like proteases for entry into host cells4,5. Consistently, carriage of putative genes involved in trypsin degradation in the gut microbiome was associated with reduced severity of diarrhoea in patients with SARS-CoV-2 infection. Thus, trypsin-degrading commensal colonization may contribute to the maintenance of intestinal homeostasis and protection from pathogen infection.
Assuntos
Microbioma Gastrointestinal , Intestino Grosso , Simbiose , Tripsina , Administração Oral , Animais , Sistemas de Secreção Bacterianos , Vacinas Bacterianas/administração & dosagem , Vacinas Bacterianas/imunologia , Bacteroidetes/isolamento & purificação , Bacteroidetes/metabolismo , COVID-19/complicações , Citrobacter rodentium/imunologia , Diarreia/complicações , Fezes/microbiologia , Microbioma Gastrointestinal/genética , Humanos , Imunoglobulina A/metabolismo , Intestino Grosso/metabolismo , Intestino Grosso/microbiologia , Camundongos , Vírus da Hepatite Murina/metabolismo , Vírus da Hepatite Murina/patogenicidade , Proteólise , SARS-CoV-2/patogenicidade , Tripsina/metabolismo , Internalização do VírusRESUMO
Group 3 innate lymphoid cells (ILC3s) are innate immune effectors that contribute to host defense. Whether ILC3 functions are stably modified after pathogen encounter is unknown. Here, we assess the impact of a time-restricted enterobacterial challenge to long-term ILC3 activation in mice. We found that intestinal ILC3s persist for months in an activated state after exposure to Citrobacter rodentium. Upon rechallenge, these "trained" ILC3s proliferate, display enhanced interleukin-22 (IL-22) responses, and have a superior capacity to control infection compared with naïve ILC3s. Metabolic changes occur in C. rodentium-exposed ILC3s, but only trained ILC3s have an enhanced proliferative capacity that contributes to increased IL-22 production. Accordingly, a limited encounter with a pathogen can promote durable phenotypic and functional changes in intestinal ILC3s that contribute to long-term mucosal defense.
Assuntos
Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Imunidade nas Mucosas , Mucosa Intestinal/imunologia , Ativação Linfocitária , Linfócitos/imunologia , Imunidade Adaptativa , Animais , Proliferação de Células , Feminino , Imunidade Inata , Memória Imunológica , Interleucinas/metabolismo , Intestinos/imunologia , Listeria monocytogenes , Listeriose/imunologia , Linfócitos/metabolismo , Masculino , Redes e Vias Metabólicas , Camundongos , Camundongos Endogâmicos C57BL , Consumo de Oxigênio , RNA-Seq , Reinfecção/imunologia , Interleucina 22RESUMO
Group 3 innate lymphoid cells (ILC3s) control the formation of intestinal lymphoid tissues and play key roles in intestinal defense. They express neuropeptide vasoactive intestinal peptide (VIP) receptor 2 (VPAC2), through which VIP modulates their function, but whether VIP exerts other effects on ILC3 remains unclear. We show that VIP promotes ILC3 recruitment to the intestine through VPAC1 independent of the microbiota or adaptive immunity. VIP is also required for postnatal formation of lymphoid tissues as well as the maintenance of local populations of retinoic acid (RA)-producing dendritic cells, with RA up-regulating gut-homing receptor CCR9 expression by ILC3s. Correspondingly, mice deficient in VIP or VPAC1 suffer a paucity of intestinal ILC3s along with impaired production of the cytokine IL-22, rendering them highly susceptible to the enteric pathogen Citrobacter rodentium This heightened susceptibility to C. rodentium infection was ameliorated by RA supplementation, adoptive transfer of ILC3s, or by recombinant IL-22. Thus, VIP regulates the recruitment of intestinal ILC3s and formation of postnatal intestinal lymphoid tissues, offering protection against enteric pathogens.
Assuntos
Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Linfócitos/imunologia , Receptores Tipo II de Peptídeo Intestinal Vasoativo/metabolismo , Peptídeo Intestinal Vasoativo/metabolismo , Animais , Células Dendríticas/imunologia , Microbioma Gastrointestinal/imunologia , Interleucinas/análise , Tecido Linfoide/citologia , Tecido Linfoide/crescimento & desenvolvimento , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores CCR/biossíntese , Receptores Tipo II de Peptídeo Intestinal Vasoativo/genética , Tretinoína/metabolismo , Peptídeo Intestinal Vasoativo/genética , Interleucina 22RESUMO
Citrobacter rodentium is a murine pathogenic bacterium that adheres to intestinal epithelial cells, resulting in loss of microvilli and pedestal formation, and alters multiple cellular processes, including actin dynamics. Translocated intimin receptor (Tir), one of its virulence factors, functions as receptor for intimin, a bacterial adhesin, thereby mediating bacterial adhesion to epithelial cells. Although robust immune responses are induced to eliminate pathogenic bacteria in the host, they are suppressed against harmless commensal bacteria. The mechanism(s) underlying such a differentiation remains unclear. This study sought to determine the roles of intimate adhesion in the induction of specific immune responses upon C. rodentium infection. To this end, microbiota-depleted mice were infected with the Tir-F strain expressing full-length Tir or mutant strains expressing the C-terminal truncated Tir that is defective in intimin binding and host cell actin polymerization. There were no differences in the colonization kinetics and Abs responses against C. rodentium LPS among the strains, whereas Abs against the virulence factors were only produced on Tir-F infection. Although there were no differences in the virulence factors mRNA expression levels, colonic hyperplasia, and bacterial translocation to the systemic organs irrespective of the strain, adhesion to colonic epithelial cells was reduced in the mutant strain-infected mice. Furthermore, transcriptomic analysis indicated that robust inflammatory and immune responses were only induced in the Tir-F-infected group and were suppressed in the mutant-infected groups. Taken together, these findings suggest that Tir-mediated intimate adhesion induces inflammatory and immune responses, resulting in the induction of virulence factor-specific Abs.
Assuntos
Aderência Bacteriana/imunologia , Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Mucosa Intestinal/patologia , Fatores de Virulência/metabolismo , Adesinas Bacterianas/metabolismo , Animais , Aderência Bacteriana/genética , Linhagem Celular Tumoral , Citrobacter rodentium/genética , Citrobacter rodentium/patogenicidade , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/patologia , Feminino , Microbioma Gastrointestinal/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Camundongos , Mutação , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/metabolismo , Organismos Livres de Patógenos EspecíficosRESUMO
Lymphotoxin beta receptor (LTßR) is a promising therapeutic target in autoimmune and infectious diseases as well as cancer. Mice with genetic inactivation of LTßR display multiple defects in development and organization of lymphoid organs, mucosal immune responses, IgA production and an autoimmune phenotype. As these defects are imprinted in embryogenesis and neonate stages, the impact of LTßR signaling in adulthood remains unclear. Here, to overcome developmental defects, we generated mice with inducible ubiquitous genetic inactivation of LTßR in adult mice (iLTßRΔ/Δ mice) and redefined the role of LTßR signaling in organization of lymphoid organs, immune response to mucosal bacterial pathogen, IgA production and autoimmunity. In spleen, postnatal LTßR signaling is required for development of B cell follicles, follicular dendritic cells (FDCs), recruitment of neutrophils and maintenance of the marginal zone. Lymph nodes of iLTßRΔ/Δ mice were reduced in size, lacked FDCs, and had disorganized subcapsular sinus macrophages. Peyer`s patches were smaller in size and numbers, and displayed reduced FDCs. The number of isolated lymphoid follicles in small intestine and colon were also reduced. In contrast to LTßR-/- mice, iLTßRΔ/Δ mice displayed normal thymus structure and did not develop signs of systemic inflammation and autoimmunity. Further, our results suggest that LTßR signaling in adulthood is required for homeostasis of neutrophils, NK, and iNKT cells, but is dispensable for the maintenance of polyclonal IgA production. However, iLTßRΔ/Δ mice exhibited an increased sensitivity to C. rodentium infection and failed to develop pathogen-specific IgA responses. Collectively, our study uncovers new insights of LTßR signaling in adulthood for the maintenance of lymphoid organs, neutrophils, NK and iNKT cells, and IgA production in response to mucosal bacterial pathogen.
Assuntos
Envelhecimento/imunologia , Tecido Linfoide/imunologia , Receptor beta de Linfotoxina/fisiologia , Animais , Anticorpos Antibacterianos/biossíntese , Anticorpos Antibacterianos/imunologia , Autoimunidade , Moléculas de Adesão Celular/metabolismo , Quimiocinas/metabolismo , Citrobacter rodentium/imunologia , Cruzamentos Genéticos , Regulação da Expressão Gênica no Desenvolvimento , Homeostase/imunologia , Imunoglobulina A/biossíntese , Imunoglobulina A/imunologia , Inflamação , Células Matadoras Naturais/imunologia , Tecido Linfoide/citologia , Receptor beta de Linfotoxina/biossíntese , Receptor beta de Linfotoxina/deficiência , Receptor beta de Linfotoxina/genética , Camundongos , Camundongos Endogâmicos MRL lpr , Camundongos Transgênicos , Neutrófilos/imunologia , Deleção de Sequência , Organismos Livres de Patógenos Específicos , Esplenomegalia/imunologiaRESUMO
TNFRSF13B encodes the transmembrane activator and CAML interactor (TACI) receptor, which drives plasma cell differentiation. Although TNFRSF13B supports host defense, dominant-negative TNFRSF13B alleles are common in humans and other species and only rarely associate with disease. We reasoned that the high frequency of disruptive TNFRSF13B alleles reflects balancing selection, the loss of function conferring advantage in some settings. Testing that concept, we investigated how a common human dominant-negative variant, TNFRSF13B A181E, imparts resistance to enteric pathogens. Mice engineered to express mono- or biallelic A144E variants of tnrsf13B, corresponding to A181E, exhibited a striking resistance to pathogenicity and transmission of Citrobacter rodentium, a murine pathogen that models enterohemorrhagic Escherichia coli, and resistance was principally owed to natural IgA deficiency in the intestine. In WT mice with gut IgA and in mutant mice reconstituted with enteric IgA obtained from WT mice, IgA induces LEE expression of encoded virulence genes, which confer pathogenicity and transmission. Taken together, our results show that C. rodentium and most likely other enteric organisms appropriated binding of otherwise protective antibodies to signal induction of the virulence program. Additionally, the high prevalence of TNFRSF13B dominant-negative variants reflects balancing selection.
Assuntos
Citrobacter rodentium/imunologia , Colite/imunologia , Infecções por Enterobacteriaceae/imunologia , Imunoglobulina A/imunologia , Proteína Transmembrana Ativadora e Interagente do CAML/genética , Alelos , Animais , Linfócitos B , Colite/microbiologia , Modelos Animais de Doenças , Resistência à Doença/genética , Infecções por Enterobacteriaceae/microbiologia , Feminino , Humanos , Imunoglobulina A/metabolismo , Mutação com Perda de Função , Ativação Linfocitária/genética , Masculino , Polimorfismo de Nucleotídeo Único/imunologia , Proteína Transmembrana Ativadora e Interagente do CAML/metabolismoRESUMO
Up to 20% of people worldwide develop gastrointestinal symptoms following a meal1, leading to decreased quality of life, substantial morbidity and high medical costs. Although the interest of both the scientific and lay communities in this issue has increased markedly in recent years, with the worldwide introduction of gluten-free and other diets, the underlying mechanisms of food-induced abdominal complaints remain largely unknown. Here we show that a bacterial infection and bacterial toxins can trigger an immune response that leads to the production of dietary-antigen-specific IgE antibodies in mice, which are limited to the intestine. Following subsequent oral ingestion of the respective dietary antigen, an IgE- and mast-cell-dependent mechanism induced increased visceral pain. This aberrant pain signalling resulted from histamine receptor H1-mediated sensitization of visceral afferents. Moreover, injection of food antigens (gluten, wheat, soy and milk) into the rectosigmoid mucosa of patients with irritable bowel syndrome induced local oedema and mast cell activation. Our results identify and characterize a peripheral mechanism that underlies food-induced abdominal pain, thereby creating new possibilities for the treatment of irritable bowel syndrome and related abdominal pain disorders.
Assuntos
Dor Abdominal/imunologia , Dor Abdominal/patologia , Alérgenos/imunologia , Hipersensibilidade Alimentar/imunologia , Alimentos/efeitos adversos , Intestinos/imunologia , Síndrome do Intestino Irritável/imunologia , Dor Abdominal/etiologia , Dor Abdominal/microbiologia , Adulto , Animais , Citrobacter rodentium/imunologia , Diarreia/imunologia , Diarreia/microbiologia , Diarreia/patologia , Infecções por Enterobacteriaceae/complicações , Infecções por Enterobacteriaceae/imunologia , Infecções por Enterobacteriaceae/microbiologia , Feminino , Hipersensibilidade Alimentar/complicações , Hipersensibilidade Alimentar/microbiologia , Hipersensibilidade Alimentar/patologia , Glutens/imunologia , Humanos , Imunoglobulina E/imunologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Mucosa Intestinal/patologia , Intestinos/microbiologia , Intestinos/patologia , Síndrome do Intestino Irritável/etiologia , Síndrome do Intestino Irritável/microbiologia , Síndrome do Intestino Irritável/patologia , Masculino , Mastócitos/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Pessoa de Meia-Idade , Leite/imunologia , Ovalbumina/imunologia , Qualidade de Vida , Receptores Histamínicos H1/metabolismo , Proteínas de Soja/imunologia , Triticum/imunologiaRESUMO
RNA helicases play roles in various essential biological processes such as RNA splicing and editing. Recent in vitro studies show that RNA helicases are involved in immune responses toward viruses, serving as viral RNA sensors or immune signaling adaptors. However, there is still a lack of in vivo data to support the tissue- or cell-specific function of RNA helicases owing to the lethality of mice with complete knockout of RNA helicases; further, there is a lack of evidence about the antibacterial role of helicases. Here, we investigated the in vivo role of Dhx15 in intestinal antibacterial responses by generating mice that were intestinal epithelial cell (IEC)-specific deficient for Dhx15 (Dhx15 f/f Villin1-cre, Dhx15ΔIEC). These mice are susceptible to infection with enteric bacteria Citrobacter rodentium (C. rod), owing to impaired α-defensin production by Paneth cells. Moreover, mice with Paneth cell-specific depletion of Dhx15 (Dhx15 f/f Defensinα6-cre, Dhx15ΔPaneth) are more susceptible to DSS (dextran sodium sulfate)-induced colitis, which phenocopy Dhx15ΔIEC mice, due to the dysbiosis of the intestinal microbiota. In humans, reduced protein levels of Dhx15 are found in ulcerative colitis (UC) patients. Taken together, our findings identify a key regulator of Wnt-induced α-defensins in Paneth cells and offer insights into its role in the antimicrobial response as well as intestinal inflammation.
Assuntos
Colite/imunologia , Defensinas/genética , Infecções por Enterobacteriaceae/imunologia , Celulas de Paneth/imunologia , RNA Helicases/genética , Via de Sinalização Wnt , Animais , Citrobacter rodentium/imunologia , Citrobacter rodentium/patogenicidade , Colite/induzido quimicamente , Colite/genética , Colite/patologia , Defensinas/imunologia , Sulfato de Dextrana/administração & dosagem , Infecções por Enterobacteriaceae/genética , Infecções por Enterobacteriaceae/microbiologia , Infecções por Enterobacteriaceae/patologia , Microbioma Gastrointestinal/imunologia , Regulação da Expressão Gênica , Humanos , Camundongos , Camundongos Transgênicos , Proteínas dos Microfilamentos/genética , Proteínas dos Microfilamentos/imunologia , Celulas de Paneth/microbiologia , Isoformas de Proteínas/genética , Isoformas de Proteínas/imunologia , RNA Helicases/imunologiaRESUMO
Type 17 cytokines have been strongly implicated in mucosal immunity, in part by regulating the production of antimicrobial peptides. Using a mouse model of Citrobacter rodentium infection, which causes colitis, we found that intestinal IL-17RA and IL-17RC were partially required for control of infection in the colon and IL-17 regulates the production of luminal hydrogen peroxide as well as expression of Tnsf13 Reduced Tnfsf13 expression was associated with a profound defect in generating C. rodentium-specific IgA+ Ab-secreting cells. Taken together, intestinal IL-17R signaling plays key roles in controlling invading pathogens, in part by regulating luminal hydrogen peroxide as well as regulating the generation of pathogen-specific IgA+ Ab-secreting cells.
Assuntos
Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Imunoglobulina A Secretora/imunologia , Mucosa Intestinal/imunologia , Oxirredutases/imunologia , Receptores de Interleucina-17/imunologia , Transdução de Sinais/imunologia , Animais , Modelos Animais de Doenças , Infecções por Enterobacteriaceae/genética , Humanos , Peróxido de Hidrogênio/imunologia , Imunoglobulina A Secretora/genética , Camundongos , Camundongos Knockout , Oxirredutases/genética , Receptores de Interleucina-17/genética , Transdução de Sinais/genéticaRESUMO
CD4+ effector lymphocytes (Teff) are traditionally classified by the cytokines they produce. To determine the states that Teff cells actually adopt in frontline tissues in vivo, we applied single-cell transcriptome and chromatin analyses to colonic Teff cells in germ-free or conventional mice or in mice after challenge with a range of phenotypically biasing microbes. Unexpected subsets were marked by the expression of the interferon (IFN) signature or myeloid-specific transcripts, but transcriptome or chromatin structure could not resolve discrete clusters fitting classic helper T cell (TH) subsets. At baseline or at different times of infection, transcripts encoding cytokines or proteins commonly used as TH markers were distributed in a polarized continuum, which was functionally validated. Clones derived from single progenitors gave rise to both IFN-γ- and interleukin (IL)-17-producing cells. Most of the transcriptional variance was tied to the infecting agent, independent of the cytokines produced, and chromatin variance primarily reflected activities of activator protein (AP)-1 and IFN-regulatory factor (IRF) transcription factor (TF) families, not the canonical subset master regulators T-bet, GATA3 or RORγ.
Assuntos
Bactérias/patogenicidade , Infecções Bacterianas/microbiologia , Linfócitos T CD4-Positivos/microbiologia , Linfócitos T CD4-Positivos/parasitologia , Colo/microbiologia , Colo/parasitologia , Microbioma Gastrointestinal , Heligmosomatoidea/patogenicidade , Enteropatias Parasitárias/parasitologia , Animais , Bactérias/imunologia , Infecções Bacterianas/genética , Infecções Bacterianas/imunologia , Infecções Bacterianas/metabolismo , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD4-Positivos/metabolismo , Cromatina/genética , Cromatina/metabolismo , Citrobacter rodentium/imunologia , Citrobacter rodentium/patogenicidade , Colo/imunologia , Colo/metabolismo , Citocinas/genética , Citocinas/metabolismo , Modelos Animais de Doenças , Perfilação da Expressão Gênica , Heligmosomatoidea/imunologia , Interações Hospedeiro-Patógeno , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Enteropatias Parasitárias/genética , Enteropatias Parasitárias/imunologia , Enteropatias Parasitárias/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Nematospiroides dubius/imunologia , Nematospiroides dubius/patogenicidade , Nippostrongylus/imunologia , Nippostrongylus/patogenicidade , Fenótipo , Salmonella enterica/imunologia , Salmonella enterica/patogenicidade , Análise de Célula Única , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , TranscriptomaRESUMO
Dendritic cells (DCs) are first in line to sense invading microbes and to deliver signals to other immune cells. Plasmacytoid DCs (pDC) produce high amounts of type I interferons (IFNs) but also regulate immune responses. Using the Clec4C (BDCA2)-diphtheria toxin receptor mouse model allowing conditional pDC depletion, we identified an essential role for pDCs in regulating intestinal inflammation locally in the gut. In pDC-depleted mice, Citrobacter rodentium infection led to enhanced activation of conventional DCs and induction of IFN-γ-producing Th1-cells in colon-draining lymph nodes, while induction of Foxp3+ /CD25+ Treg and IL-17-producing Th17 cells was impaired. Concomitantly, F4/80+ macrophages accumulated into the colon lamina propria in excess, and levels of Il-1ß and Tnf transcripts increased and Foxp3+ Treg were fewer. Our results indicate that pDCs control inflammation in the gut during C. rodentium infection and that they have an important immune regulatory role in colon-draining lymph nodes.
Assuntos
Citrobacter rodentium/imunologia , Colite/imunologia , Colo/imunologia , Células Dendríticas/imunologia , Imunidade/imunologia , Linfonodos/imunologia , Animais , Infecções por Enterobacteriaceae/imunologia , Feminino , Fatores de Transcrição Forkhead/imunologia , Fator de Crescimento Semelhante a EGF de Ligação à Heparina/imunologia , Inflamação/imunologia , Subunidade alfa de Receptor de Interleucina-2/imunologia , Mucosa Intestinal/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Células Th17/imunologiaRESUMO
As the interface between the gut microbiota and the mucosal immune system, there has been great interest in the maintenance of colonic epithelial integrity through mitochondrial oxidation of butyrate, a short-chain fatty acid produced by the gut microbiota. Herein, we showed that the intestinal epithelium could also oxidize long-chain fatty acids, and that luminally delivered acylcarnitines in bile could be consumed via apical absorption by the intestinal epithelium, resulting in mitochondrial oxidation. Finally, intestinal inflammation led to mitochondrial dysfunction in the apical domain of the surface epithelium that may reduce the consumption of fatty acids, contributing to higher concentrations of fecal acylcarnitines in murine Citrobacter rodentium-induced colitis and human inflammatory bowel disease. These results emphasized the importance of both the gut microbiota and the liver in the delivery of energy substrates for mitochondrial metabolism by the intestinal epithelium.
Assuntos
Carnitina/análogos & derivados , Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Doenças Inflamatórias Intestinais/imunologia , Mucosa Intestinal/imunologia , Fígado/imunologia , Mitocôndrias/imunologia , Animais , Células CACO-2 , Carnitina/imunologia , Infecções por Enterobacteriaceae/patologia , Feminino , Humanos , Doenças Inflamatórias Intestinais/microbiologia , Doenças Inflamatórias Intestinais/patologia , Mucosa Intestinal/microbiologia , Mucosa Intestinal/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Mitocôndrias/patologiaRESUMO
Citrobacter rodentium is an extracellular enteric bacterial pathogen that induces both innate and adaptive immunity in mice, its natural host. Here, we detail the step-by-step procedure to evaluate the immune responses in a mouse model of C. rodentium infection. We describe the methods to establish infection, isolate group 3 innate lymphoid cells from lamina propria lymphocytes, and analyze their response. We also assess the response of T follicular helper cells and germinal center B cells. For complete details on the use and execution of this protocol, please refer to Guo et al. (2015), Kennedy and Hartland, (2018), and Wang et al. (2020).
Assuntos
Separação Celular/métodos , Modelos Animais de Doenças , Infecções por Enterobacteriaceae/imunologia , Imunidade Adaptativa/imunologia , Animais , Linfócitos B/imunologia , Citrobacter rodentium/imunologia , Citrobacter rodentium/patogenicidade , Colite/imunologia , Colo/imunologia , Microbioma Gastrointestinal , Centro Germinativo/imunologia , Imunidade Inata/imunologia , Mucosa Intestinal/imunologia , Linfócitos/citologia , CamundongosRESUMO
Countless numbers of bacteria inhabit the intestinal tract. One of the important functions of gut microbiota is the "colonization resistance" against infection by pathogenic microorganisms. However, detailed mechanism of the colonization resistance of intestinal bacteria is still largely unknown. We tried to identify molecular and cellular mechanism of it and found that antigen presentation by dendritic cells is required for the induction of intestinal segmented filamentous bacteria (SFB)-induced T helper 17 (Th17) cells that contribute to the protection against infection by Citrobacter rodentium. We further identified that gut Th17 cells selectively recognize antigens derived from SFB. We also revealed that SFB induce α1,2-fucose, one of carbohydrate chains, expressed on the intestinal epithelial cells mediated by group 3 innate lymphoid cells. Epithelial α1,2-fucose protected against infection by pathogenic bacterium Salmonella typhimurium. Furthermore, it was found that intestinal bacteria inhibit colonization of the pathogenic fungus Candida albicans as well as pathogenic bacteria. From these studies, detailed mechanism of "colonization resistance" against pathogenic microorganisms by intestinal bacteria has been clarified.