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1.
J Clin Periodontol ; 51(3): 309-318, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38088457

RESUMO

AIM: To evaluate the effect of different oral irrigators on the sub-gingival microbiome composition in patients with naturally occurring plaque-induced gingivitis. MATERIALS AND METHODS: Sub-gingival plaque was collected from adults participating in a clinical trial assessing the efficacy of oral hygiene with two different oral irrigators (Waterpik Water Flosser [Group 1] and Oral-B Water Flosser [Group 2]) versus dental flossing (Group 3) for microbiome analysis. Plaque samples were reflective of naturally occurring plaque-induced gingivitis at baseline and of gingival health at the endpoint (4 weeks). Clinical measures of gingival inflammation were collected, and the sub-gingival microbiome was analysed by 16S rRNA sequencing to identify amplicon sequence variants. RESULTS: Oral hygiene instruction with self-performed manual toothbrushing and water-jet irrigation led to significant reductions in inflammation for all groups; both oral irrigators outperformed flossing in bleeding-on-probing reduction (p < .001). Microbiome diversity of sub-gingival plaque remained relatively stable over time, but significant changes were noted in certain taxa, consistent with increases in the relative abundance of commensals and reductions in late colonizers and periodontal pathogens in the water-jet groups. CONCLUSIONS: Reduction in gingival inflammation at 4 weeks within the water-jet groups is accompanied by slight but critical changes in microbiome composition. Although biodiversity does not substantially change within 4 weeks during the resolution of naturally induced gingivitis, significant relative increases in commensal early colonizers such as Streptococcus, Veillonella and Fusobacterium were accompanied by a shift towards a less anaerobic microbiota associated with return to health. These changes were contingent upon the type of interdental hygiene, with Group 1 exhibiting more significant alterations in microbiome composition towards a periodontal-health-compatible community.


Assuntos
Placa Dentária , Gengivite , Adulto , Humanos , Higiene Bucal , Dispositivos para o Cuidado Bucal Domiciliar , Análise de Dados Secundários , RNA Ribossômico 16S , Índice de Placa Dentária , Escovação Dentária , Gengivite/prevenção & controle , Placa Dentária/prevenção & controle , Inflamação , Água , Método Simples-Cego
2.
Proc Natl Acad Sci U S A ; 117(1): 602-609, 2020 01 07.
Artigo em Inglês | MEDLINE | ID: mdl-31836694

RESUMO

Vitamin B12 (VB12) is a critical micronutrient that controls DNA metabolic pathways to maintain the host genomic stability and tissue homeostasis. We recently reported that the newly discovered commensal Propionibacterium, P. UF1, regulates the intestinal immunity to resist pathogen infection, which may be attributed in part to VB12 produced by this bacterium. Here we demonstrate that VB12 synthesized by P. UF1 is highly dependent on cobA gene-encoding uroporphyrinogen III methyltransferase, and that this vitamin distinctively regulates the cobA operon through its 5' untranslated region (5' UTR). Furthermore, conserved secondary structure and mutagenesis analyses revealed a VB12-riboswitch, cbiMCbl (140 bp), within the 5' UTR that controls the expression of downstream genes. Intriguingly, ablation of the cbiMCbl significantly dysregulates the biosynthesis of VB12, illuminating the significance of this riboswitch for bacterial VB12 biosynthesis. Collectively, our finding is an in-depth report underscoring the regulation of VB12 within the beneficial P. UF1 bacterium, through which the commensal metabolic network may improve gut bacterial cross-feeding and human health.


Assuntos
Regulação Bacteriana da Expressão Gênica , Propionibacterium/metabolismo , Riboswitch/genética , Vitamina B 12/biossíntese , Regiões 5' não Traduzidas/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Microbioma Gastrointestinal/fisiologia , Metiltransferases/genética , Metiltransferases/metabolismo , Mutagênese Sítio-Dirigida , Óperon/genética , Probióticos/metabolismo , Propionibacterium/genética
3.
Gastroenterology ; 160(4): 1240-1255.e3, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33189700

RESUMO

BACKGROUND & AIMS: The down-regulated in adenoma (DRA) protein, encoded by SLC26A3, a key intestinal chloride anion exchanger, has recently been identified as a novel susceptibility gene for inflammatory bowel disease (IBD). However, the mechanisms underlying the increased susceptibility to inflammation induced by the loss of DRA remain elusive. Compromised barrier is a key event in IBD pathogenesis. The current studies were undertaken to elucidate the impact of DRA deficiency on epithelial barrier integrity and to define underlying mechanisms. METHODS: Wild-type and DRA-knockout (KO) mice and crypt-derived colonoids were used as models for intestinal epithelial response. Paracellular permeability was measured by using fluorescein isothiocyanate-dextran flux. Immunoblotting, immunofluorescence, immunohistochemistry, and ribonucleoprotein immunoprecipitation assays were performed. Gut microbiome analysis was conducted to investigate the impact of DRA deficiency on gut microbial communities. RESULTS: DRA-KO mice exhibited an increased colonic paracellular permeability with significantly decreased levels of tight junction/adherens junction proteins, including ZO-1, occludin, and E-cadherin. A similar expression pattern of occludin and E-cadherin was observed in colonoids derived from DRA-KO mice and short hairpin RNA-mediated DRA knockdown in Caco-2 cells. Microbial analysis showed gut dysbiosis in DRA-KO mice. However, cohousing studies showed that dysbiosis played only a partial role in maintaining tight junction protein expression. Furthermore, our results showed increased binding of RNA-binding protein CUGBP1 with occludin and E-cadherin genes in DRA-KO mouse colon, suggesting that posttranscriptional mechanisms play a key role in gut barrier dysfunction. CONCLUSIONS: To our knowledge, our studies demonstrate a novel role of DRA in maintaining the intestinal epithelial barrier function and potential implications of its dysregulation in IBD pathogenesis.


Assuntos
Antiporters/deficiência , Antiportadores de Cloreto-Bicarbonato/deficiência , Disbiose/imunologia , Doenças Inflamatórias Intestinais/patologia , Mucosa Intestinal/patologia , Transportadores de Sulfato/deficiência , Animais , Antiporters/genética , Proteínas CELF1/metabolismo , Células CACO-2 , Caderinas/metabolismo , Antiportadores de Cloreto-Bicarbonato/genética , Modelos Animais de Doenças , Disbiose/microbiologia , Disbiose/patologia , Técnicas de Silenciamento de Genes , Humanos , Doenças Inflamatórias Intestinais/imunologia , Doenças Inflamatórias Intestinais/microbiologia , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Masculino , Camundongos , Camundongos Knockout , Ocludina/metabolismo , Permeabilidade , Transportadores de Sulfato/genética , Junções Íntimas/patologia
4.
EMBO J ; 34(7): 881-95, 2015 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-25666591

RESUMO

Intestinal immune regulatory signals govern gut homeostasis. Breakdown of such regulatory mechanisms may result in inflammatory bowel disease (IBD). Lactobacillus acidophilus contains unique surface layer proteins (Slps), including SlpA, SlpB, SlpX, and lipoteichoic acid (LTA), which interact with pattern recognition receptors to mobilize immune responses. Here, to elucidate the role of SlpA in protective immune regulation, the NCK2187 strain, which solely expresses SlpA, was generated. NCK2187 and its purified SlpA bind to the C-type lectin SIGNR3 to exert regulatory signals that result in mitigation of colitis, maintenance of healthy gastrointestinal microbiota, and protected gut mucosal barrier function. However, such protection was not observed in Signr3(-/-) mice, suggesting that the SlpA/SIGNR3 interaction plays a key regulatory role in colitis. Our work presents critical insights into SlpA/SIGNR3-induced responses that are integral to the potential development of novel biological therapies for autoinflammatory diseases, including IBD.


Assuntos
Antígenos CD/imunologia , Proteínas de Bactérias/imunologia , Doenças Inflamatórias Intestinais/imunologia , Mucosa Intestinal/imunologia , Lactobacillus acidophilus/imunologia , Lectinas Tipo C/imunologia , Animais , Antígenos CD/genética , Proteínas de Bactérias/genética , Doenças Inflamatórias Intestinais/genética , Doenças Inflamatórias Intestinais/microbiologia , Doenças Inflamatórias Intestinais/patologia , Mucosa Intestinal/patologia , Lactobacillus acidophilus/genética , Lectinas Tipo C/genética , Lipopolissacarídeos/genética , Lipopolissacarídeos/imunologia , Camundongos , Camundongos Knockout , Ligação Proteica/genética , Ligação Proteica/imunologia , Ácidos Teicoicos/genética , Ácidos Teicoicos/imunologia
5.
Proc Natl Acad Sci U S A ; 109(26): 10462-7, 2012 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-22689992

RESUMO

An imbalance of commensal bacteria and their gene products underlies mucosal and, in particular, gastrointestinal inflammation and a predisposition to cancer. Lactobacillus species have received considerable attention as examples of beneficial microbiota. We have reported previously that deletion of the phosphoglycerol transferase gene that is responsible for lipoteichoic acid (LTA) biosynthesis in Lactobacillus acidophilus (NCK2025) rendered this bacterium able to significantly protect mice against induced colitis when delivered orally. Here we report that oral treatment with LTA-deficient NCK2025 normalizes innate and adaptive pathogenic immune responses and causes regression of established colonic polyps. This study reveals the proinflammatory role of LTA and the ability of LTA-deficient L. acidophilus to regulate inflammation and protect against colonic polyposis in a unique mouse model.


Assuntos
Polipose Adenomatosa do Colo/imunologia , Lactobacillus acidophilus/genética , Lipopolissacarídeos/genética , Ácidos Teicoicos/genética , Polipose Adenomatosa do Colo/patologia , Animais , Camundongos , Linfócitos T Reguladores/imunologia
6.
J Infect Dis ; 210(9): 1499-507, 2014 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-24829464

RESUMO

Ingestion of Bacillus anthracis spores causes gastrointestinal (GI) anthrax. Humoral immune responses, particularly immunoglobulin A (IgA)-secreting B-1 cells, play a critical role in the clearance of GI pathogens. Here, we investigated whether B. anthracis impacts the function of colonic B-1 cells to establish active infection. GI anthrax led to significant inhibition of immunoglobulins (eg, IgA) and increased expression of program death 1 on B-1 cells. Furthermore, infection also diminished type 2 innate lymphoid cells (ILC2) and their ability to enhance differentiation and immunoglobulin production by secreting interleukin 5 (IL-5). Such B-1-cell and ILC2 dysfunction is potentially due to cleavage of p38 and Erk1/2 mitogen-activated protein kinases in these cells. Conversely, mice that survived infection generated neutralizing antibodies via the formation of robust germinal center B cells in Peyer's patches and had restored B-1-cell and ILC2 function. These data may provide additional insight for designing efficacious vaccines and therapeutics against this deadly pathogen.


Assuntos
Antraz/imunologia , Linfócitos B/fisiologia , Bacillus anthracis/fisiologia , Gastroenteropatias/imunologia , Animais , Bacillus anthracis/imunologia , Colo/imunologia , Colo/microbiologia , Citometria de Fluxo , Imunidade Celular/imunologia , Camundongos , Reação em Cadeia da Polimerase em Tempo Real
7.
Proc Natl Acad Sci U S A ; 108 Suppl 1: 4623-30, 2011 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-21282652

RESUMO

Imbalance in the regulatory immune mechanisms that control intestinal cellular and bacterial homeostasis may lead to induction of the detrimental inflammatory signals characterized in humans as inflammatory bowel disease. Induction of proinflammatory cytokines (i.e., IL-12) induced by dendritic cells (DCs) expressing pattern recognition receptors may skew naive T cells to T helper 1 polarization, which is strongly implicated in mucosal autoimmunity. Recent studies show the ability of probiotic microbes to treat and prevent numerous intestinal disorders, including Clostridium difficile-induced colitis. To study the molecular mechanisms involved in the induction and repression of intestinal inflammation, the phosphoglycerol transferase gene that plays a key role in lipoteichoic acid (LTA) biosynthesis in Lactobacillus acidophilus NCFM (NCK56) was deleted. The data show that the L. acidophilus LTA-negative in LTA (NCK2025) not only down-regulated IL-12 and TNFα but also significantly enhanced IL-10 in DCs and controlled the regulation of costimulatory DC functions, resulting in their inability to induce CD4(+) T-cell activation. Moreover, treatment of mice with NCK2025 compared with NCK56 significantly mitigated dextran sulfate sodium and CD4(+)CD45RB(high)T cell-induced colitis and effectively ameliorated dextran sulfate sodium-established colitis through a mechanism that involves IL-10 and CD4(+)FoxP3(+) T regulatory cells to dampen exaggerated mucosal inflammation. Directed alteration of cell surface components of L. acidophilus NCFM establishes a potential strategy for the treatment of inflammatory intestinal disorders.


Assuntos
Autoimunidade/imunologia , Colite/imunologia , Colite/microbiologia , Regulação da Expressão Gênica/imunologia , Lactobacillus acidophilus/metabolismo , Lipopolissacarídeos/deficiência , Animais , Linfócitos T CD4-Positivos/imunologia , Colite/induzido quimicamente , Primers do DNA/genética , Sulfato de Dextrana/toxicidade , Citometria de Fluxo , Imunofluorescência , Deleção de Genes , Proteínas de Homeodomínio/genética , Interleucina-10/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/genética , Reação em Cadeia da Polimerase , Ácidos Teicoicos , Transferases (Outros Grupos de Fosfato Substituídos)/genética
8.
Mucosal Immunol ; 2024 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-39255854

RESUMO

Dietary micronutrients, particularly vitamin B12 (VB12), profoundly influence the physiological maintenance and function of intestinal cells. However, it is still unclear whether VB12 modulates the transcriptional and metabolic programming of ileal macrophages (iMacs), thereby contributing to intestinal homeostasis. Using multiomic approaches, we demonstrated that VB12 primarily supports the cell cycle activity and mitochondrial metabolism of iMacs, resulting in increased cell frequency compared to VB12 deficiency. VB12 also retained the ability to promote maintenance and metabolic regulation of iMacs during intestinal infection with Salmonella Typhimurium (STm). On the contrary, depletion of iMacs by inhibiting CSF1R signaling significantly increased host susceptibility to STm and prevented VB12-mediated pathogen reduction. These results thus suggest that regulation of VB12-dependent iMacs critically controls STm expansion, which may be of new relevance to advance our understanding of this vitamin and to strategically formulate sustainable therapeutic nutritional regimens that improve human gut health.

9.
Sci Adv ; 10(13): eadi4310, 2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38536923

RESUMO

The maintenance of regulatory T (Treg) cells critically prevents autoimmunity. Pre-B cell leukemia transcription factor 1 (Pbx1) variants are associated with lupus susceptibility, particularly through the expression of a dominant negative isoform Pbx1-d in CD4+ T cells. Pbx1-d overexpression impaired Treg cell homeostasis and promoted inflammatory CD4+ T cells. Here, we showed a high expression of Pbx1 in human and murine Treg cells, which is decreased in lupus patients and mice. Pbx1 deficiency or Pbx1-d overexpression reduced the number, stability, and suppressive activity of Treg cells, which increased murine responses to immunization and autoimmune induction. Mechanistically, Pbx1 deficiency altered the expression of genes implicated in cell cycle and apoptosis in Treg cells. Intriguingly, Rtkn2, a Rho-GTPase previously associated with Treg homeostasis, was directly transactivated by Pbx1. Our results suggest that the maintenance of Treg cell homeostasis and stability by Pbx1 through cell cycle progression prevent the expansion of inflammatory T cells that otherwise exacerbates lupus progression in the hosts.


Assuntos
Lúpus Eritematoso Sistêmico , Linfócitos T Reguladores , Animais , Humanos , Camundongos , Divisão Celular , Fator de Transcrição 1 de Leucemia de Células Pré-B/genética , Fator de Transcrição 1 de Leucemia de Células Pré-B/metabolismo , Isoformas de Proteínas/genética , Lúpus Eritematoso Sistêmico/genética
10.
iScience ; 27(4): 109480, 2024 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-38715940

RESUMO

Ischemic stroke is the second leading cause of death and disability worldwide, and efforts to prevent stroke, mitigate secondary neurological damage, and promote neurological recovery remain paramount. Recent findings highlight the critical importance of microbiome-related metabolites, including vitamin B12 (VB12), in alleviating toxic stroke-associated neuroinflammation. Here, we showed that VB12 tonically programmed genes supporting microglial cell division and activation and critically controlled cellular fatty acid metabolism in homeostasis. Intriguingly, VB12 promoted mitochondrial transcriptional and metabolic activities and significantly restricted stroke-associated gene alterations in microglia. Furthermore, VB12 differentially altered the functions of microglial subsets during the acute phase of ischemic stroke, resulting in reduced brain damage and improved neurological function. Pharmacological depletion of microglia before ischemic stroke abolished VB12-mediated neurological improvement. Thus, our preclinical studies highlight the relevance of VB12 in the functional programming of microglia to alleviate neuroinflammation, minimize ischemic injury, and improve host neurological recovery after ischemic stroke.

11.
STAR Protoc ; 4(1): 101936, 2023 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-36520632

RESUMO

Intestinal epithelium is composed of several cell types, which can be dissociated but difficult to maintain high cell viability due to anoikis. Herein, we describe a step-by-step protocol for the isolation of highly viable intestinal epithelial cells using ethylenediaminetetraacetate acid and TrypLE Express, which can subsequently be employed for multi-omic analyses, including single-cell RNA sequencing. For complete details on the use and execution of this protocol, please refer to Ge et al. (2022).1.


Assuntos
Intestinos , Multiômica , Animais , Camundongos , Células Epiteliais , Mucosa Intestinal , Sobrevivência Celular
12.
iScience ; 26(7): 107122, 2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37416482

RESUMO

Gut dysbiosis has been associated with lupus pathogenesis, and fecal microbiota transfers (FMT) from lupus-prone mice shown to induce autoimmune activation into healthy mice. The immune cells of lupus patients exhibit an increased glucose metabolism and treatments with 2-deoxy-D-glucose (2DG), a glycolysis inhibitor, are therapeutic in lupus-prone mice. Here, we showed in two models of lupus with different etiologies that 2DG altered the composition of the fecal microbiome and associated metabolites. In both models, FMT from 2DG-treated mice protected lupus-prone mice of the same strain from the development of glomerulonephritis, reduced autoantibody production as well as the activation of CD4+ T cells and myeloid cells as compared to FMT from control mice. Thus, we demonstrated that the protective effect of glucose inhibition in lupus is transferable through the gut microbiota, directly linking alterations in immunometabolism to gut dysbiosis in the hosts.

13.
Nutrients ; 14(14)2022 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-35889782

RESUMO

Vitamin B12 (VB12) is a micronutrient that is essential for DNA synthesis and cellular energy production. We recently demonstrated that VB12 oral supplementation coordinates ileal epithelial cells (iECs) and gut microbiota functions to resist pathogen colonization in mice, but it remains unclear whether VB12 directly modulates the cellular homeostasis of iECs derived from humans. Here, we integrated transcriptomic, metabolomic, and epigenomic analyses to identify VB12-dependent molecular and metabolic pathways in human iEC microtissue cultures. RNA sequencing (RNA-seq) revealed that VB12 notably activated genes involved in fatty acid metabolism and epithelial cell proliferation while suppressing inflammatory responses in human iECs. Untargeted metabolite profiling demonstrated that VB12 facilitated the biosynthesis of amino acids and methyl groups, particularly S-adenosylmethionine (SAM), and supported the function of the mitochondrial carnitine shuttle and TCA cycle. Further, genome-wide DNA methylation analysis illuminated a critical role of VB12 in sustaining cellular methylation programs, leading to differential CpG methylation of genes associated with intestinal barrier function and cell proliferation. Together, these findings suggest an essential involvement of VB12 in directing the fatty acid and mitochondrial metabolisms and reconfiguring the epigenome of human iECs to potentially support cellular oxygen utilization and cell proliferation.


Assuntos
Epigenômica , Vitamina B 12 , Animais , Epigênese Genética , Células Epiteliais/metabolismo , Ácidos Graxos/metabolismo , Humanos , Camundongos , Vitamina B 12/metabolismo
14.
J Exp Med ; 219(7)2022 07 04.
Artigo em Inglês | MEDLINE | ID: mdl-35674742

RESUMO

Deprivation of vitamin B12 (VB12) is linked to various diseases, but the underlying mechanisms in disease progression are poorly understood. Using multiomic approaches, we elucidated the responses of ileal epithelial cells (iECs) and gut microbiome to VB12 dietary restriction. Here, VB12 deficiency impaired the transcriptional and metabolic programming of iECs and reduced epithelial mitochondrial respiration and carnitine shuttling during intestinal Salmonella Typhimurium (STm) infection. Fecal microbial and untargeted metabolomic profiling identified marked changes related to VB12 deficiency, including reductions of metabolites potentially activating mitochondrial ß-oxidation in iECs and short-chain fatty acids (SCFAs). Depletion of SCFA-producing microbes by streptomycin treatment decreased the VB12-dependent STm protection. Moreover, compromised mitochondrial function of iECs correlated with declined cell capability to utilize oxygen, leading to uncontrolled oxygen-dependent STm expansion in VB12-deficient mice. Our findings uncovered previously unrecognized mechanisms through which VB12 coordinates ileal epithelial mitochondrial homeostasis and gut microbiota to regulate epithelial oxygenation, resulting in the control of aerobic STm infection.


Assuntos
Microbiota , Infecções por Salmonella , Animais , Células Epiteliais , Camundongos , Oxigênio , Vitamina B 12
15.
iScience ; 25(11): 105437, 2022 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-36388972

RESUMO

Ischemic stroke critically impacts neurovascular homeostasis, potentially resulting in neurological disorders. However, the mechanisms through which stroke-induced inflammation modifies the molecular and metabolic circuits, particularly in ileal epithelial cells (iECs), currently remain elusive. Using multiomic approaches, we illustrated that stroke impaired the ileal microbiome and associated metabolites, leading to increased inflammatory signals and altered metabolites, potentially deteriorating the iEC homeostasis. Bulk transcriptomic and metabolomic profiling demonstrated that stroke enhanced fatty acid oxidation while reducing the tricarboxylic acid (TCA) cycle in iECs within the first day after stroke. Intriguingly, single-cell RNA sequencing analysis revealed that stroke dysregulated cell-type-specific gene responses within iECs and reduced frequencies of goblet and tuft cells. Additionally, stroke augmented interleukin-17A+ γδ T cells but decreased CD4+ T cells in the ileum. Collectively, our findings provide a comprehensive overview of stroke-induced intestinal dysbiosis and unveil responsive gene programming within iECs with implications for disease development.

16.
Infect Immun ; 79(5): 1863-72, 2011 May.
Artigo em Inglês | MEDLINE | ID: mdl-21343355

RESUMO

Citrobacter rodentium infection of mice induces cell-mediated immune responses associated with crypt hyperplasia and epithelial ß-catenin signaling. Recent data suggest that phosphatidylinositol-3-kinase (PI3K)/Akt signaling cooperates with Wnt to activate ß-catenin in intestinal stem and progenitor cells through phosphorylation at Ser552 (P-ß-catenin(552)). Our aim was to determine whether epithelial PI3K/Akt activation is required for ß-catenin signaling and host defense against C. rodentium. C57BL/6 mice were infected with C. rodentium and treated with dimethyl sulfoxide (DMSO) (vehicle control) or with the PI3K inhibitor LY294002 or wortmannin. The effects of infection on PI3K activation and ß-catenin signaling were analyzed by immunohistochemistry. The effects of PI3K inhibition on host defense were analyzed by the quantification of splenic and colon bacterial clearance, and adaptive immune responses were measured by real-time PCR (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). Increased numbers of P-ß-catenin(552)-stained epithelial cells were found throughout expanded crypts in C. rodentium colitis. We show that the inhibition of PI3K signaling attenuates epithelial Akt activation, the Ser552 phosphorylation and activation of ß-catenin, and epithelial cell proliferative responses during C. rodentium infection. PI3K inhibition impairs bacterial clearance despite having no impact on mucosal cytokine (gamma interferon [IFN-γ], tumor necrosis factor [TNF], interleukin-17 [IL-17], and IL-1ß) or chemokine (CXCL1, CXCL5, CXCL9, and CXCL10) induction. The results suggest that the host defense against C. rodentium requires epithelial PI3K activation to induce Akt-mediated ß-catenin signaling and the clearance of C. rodentium independent of adaptive immune responses.


Assuntos
Citrobacter rodentium/imunologia , Infecções por Enterobacteriaceae/imunologia , Infecções por Enterobacteriaceae/metabolismo , Células Epiteliais/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais/imunologia , beta Catenina/metabolismo , Animais , Colite/imunologia , Colite/metabolismo , Colite/patologia , Infecções por Enterobacteriaceae/patologia , Ativação Enzimática/efeitos dos fármacos , Ativação Enzimática/imunologia , Inibidores Enzimáticos/farmacologia , Ensaio de Imunoadsorção Enzimática , Células Epiteliais/imunologia , Células Epiteliais/patologia , Imunofluorescência , Imuno-Histoquímica , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas c-akt/imunologia , Proteínas Proto-Oncogênicas c-akt/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos
17.
J Immune Based Ther Vaccines ; 8(1): 2, 2010 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-20181102

RESUMO

Studies have shown that CpG oligodeoxyribonucleotides (ODN) protect mice from various bacterial pathogens, including Burkholderia pseudomallei and Francisella tularensis live vaccine strain (LVS), when administered before parenteral challenge. Given the potential to develop CpG ODN as a pre-treatment for multiple bacterial biological warfare agents, we examined survival, histopathology, and cytokine data from CpG ODN-treated C57BL/6 mice to determine whether previously-reported protection extended to aerosolized B. pseudomallei 1026b and highly virulent F. tularensis Schu S4 infections. We found that, although CpG ODN protected mice from aerosolized B. pseudomallei challenges, the immunostimulant failed to benefit the animals exposed to F. tularensis Schu S4 aerosols. Our results, which contrast with earlier F. tularensis LVS studies, highlight potential differences in Francisella species pathogenesis and underscore the need to evaluate immunotherapies against human pathogenic species.

18.
Mucosal Immunol ; 13(1): 34-46, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31619761

RESUMO

Microbial interaction with the host through sensing receptors, including SIGNR1, sustains intestinal homeostasis against pathogenic inflammation. The newly discovered commensal Propionibacterium strain, P. UF1, regulates the intestinal immunity against pathogen challenge. However, the molecular events driving intestinal phagocytic cell response, including colonic dendritic cells (DCs), by this bacterium are still elusive. Here, we demonstrate that the glycosylation of bacterial large surface layer protein A (LspA) by protein O-mannosyltransferase 1 (Pmt1) regulates the interaction with SIGNR1, resulting in the control of DC transcriptomic and metabolomic machineries. Programmed DCs promote protective T cell response to intestinal Listeria infection and resist chemically induced colitis in mice. Thus, our findings may highlight a novel molecular mechanism by which commensal surface glycosylation interacting with SIGNR1 directs the intestinal homeostasis to potentially protect the host against proinflammatory signals inducing colonic tissue damage.


Assuntos
Proteínas de Bactérias/metabolismo , Moléculas de Adesão Celular/metabolismo , Colite/imunologia , Colo/imunologia , Células Dendríticas/imunologia , Doenças Inflamatórias Intestinais/imunologia , Lectinas Tipo C/metabolismo , Listeria/fisiologia , Listeriose/imunologia , Propionibacterium/metabolismo , Receptores de Superfície Celular/metabolismo , Linfócitos T/imunologia , Animais , Proteínas de Bactérias/genética , Moléculas de Adesão Celular/genética , Diferenciação Celular , Células Cultivadas , Colite/induzido quimicamente , Humanos , Lectinas Tipo C/genética , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Ligação Proteica , Receptores de Superfície Celular/genética , Simbiose
19.
Sci Transl Med ; 12(551)2020 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-32641487

RESUMO

The autoimmune disease systemic lupus erythematosus (SLE) is characterized by the production of pathogenic autoantibodies. It has been postulated that gut microbial dysbiosis may be one of the mechanisms involved in SLE pathogenesis. Here, we demonstrate that the dysbiotic gut microbiota of triple congenic (TC) lupus-prone mice (B6.Sle1.Sle2.Sle3) stimulated the production of autoantibodies and activated immune cells when transferred into germfree congenic C57BL/6 (B6) mice. Fecal transfer to B6 mice induced autoimmune phenotypes only when the TC donor mice exhibited autoimmunity. Autoimmune pathogenesis was mitigated by horizontal transfer of the gut microbiota between co-housed lupus-prone TC mice and control congenic B6 mice. Metabolomic screening identified an altered distribution of tryptophan metabolites in the feces of TC mice including an increase in kynurenine, which was alleviated after antibiotic treatment. Low dietary tryptophan prevented autoimmune pathology in TC mice, whereas high dietary tryptophan exacerbated disease. Reducing dietary tryptophan altered gut microbial taxa in both lupus-prone TC mice and control B6 mice. Consequently, fecal transfer from TC mice fed a high tryptophan diet, but not a low tryptophan diet, induced autoimmune phenotypes in germfree B6 mice. The interplay of gut microbial dysbiosis, tryptophan metabolism and host genetic susceptibility in lupus-prone mice suggest that aberrant tryptophan metabolism may contribute to autoimmune activation in this disease.


Assuntos
Microbioma Gastrointestinal , Lúpus Eritematoso Sistêmico , Animais , Autoimunidade , Disbiose , Camundongos , Camundongos Endogâmicos C57BL , Triptofano
20.
Microb Pathog ; 46(5): 283-7, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19249344

RESUMO

LcrV is a key Yersinia pestis antigen, immune regulator, and component of the type III secretion system (T3SS). Researchers have shown that N-acyl-homoserine lactones (AHLs) can down-regulate the expression of the LcrV homolog, PcrV, in Pseudomonas aeruginosa. Using ELISA, western blot, DNA microarray analysis, and real time PCR we demonstrate that the addition of AHL molecules N-octanoyl-homoserine lactone (C8) or N-(3-oxooctanoyl)-homoserine lactone (oxo-C8) to Y. pestis cultures down-regulates LcrV protein expression. DNA microarray analysis shows 10 additional T3SS genes are consistently down-regulated by C8 or oxo-C8. This is the first report demonstrating that AHLs regulate Y. pestis virulence factor expression.


Assuntos
Antígenos de Bactérias/genética , Regulação para Baixo , Homosserina/análogos & derivados , Lactonas/metabolismo , Proteínas Citotóxicas Formadoras de Poros/genética , Percepção de Quorum , Fatores de Virulência/genética , Yersinia pestis/fisiologia , Antígenos de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Homosserina/metabolismo , Proteínas Citotóxicas Formadoras de Poros/metabolismo , Fatores de Virulência/metabolismo , Yersinia pestis/genética
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