RESUMO
Lentinan (LNT), a natural polysaccharide, has been reported to exhibit immunomodulatory effects in the intestine after oral administration. Herein, we aimed to investigate the lymphatic transport of LNT in Peyer's patches (PPs) by traceable fluorescent labeling and to explore whether/how LNT contacts related immune cells. Near-infrared imaging confirmed the absorption of LNT in the small intestinal segment and its accumulation within PPs after oral administration. Subsequently, tissue imaging confirmed that M cells are the main cells responsible for transporting LNT to PPs, and an M cell model was established to explore the involvement of Dectin-1 in the absorption process. Systematic in vitro and in vivo studies revealed that the Dectin-1 further mediates the uptake of LNT by mononuclear phagocytes in PPs. Moreover, LNT can promote the proliferation and differentiation of mononuclear phagocytes, thereby activating immune responses. In summary, this study elucidates the pharmacokinetic mechanisms by which LNT exerts oral immunomodulatory effects, providing a theoretical basis for the development and application of other polysaccharides.
Assuntos
Lectinas Tipo C , Lentinano , Nódulos Linfáticos Agregados , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/efeitos dos fármacos , Nódulos Linfáticos Agregados/metabolismo , Animais , Lentinano/farmacologia , Lentinano/química , Lectinas Tipo C/metabolismo , Camundongos , Administração Oral , Fagócitos/efeitos dos fármacos , Fagócitos/metabolismo , Fagócitos/imunologia , Imunomodulação/efeitos dos fármacos , Masculino , Camundongos Endogâmicos BALB C , Células MRESUMO
Post-injury dysfunction of humoral immunity accounts for infections and poor outcomes in cardiovascular diseases. Among immunoglobulins (Ig), IgA, the most abundant mucosal antibody, is produced by plasma B cells in intestinal Peyer's patches (PP) and lamina propria. Here we show that patients with stroke and myocardial ischemia (MI) had strongly reduced IgA blood levels. This was phenocopied in experimental mouse models where decreased plasma and fecal IgA were accompanied by rapid loss of IgA-producing plasma cells in PP and lamina propria. Reduced plasma IgG was detectable in patients and experimental mice 3-10 d after injury. Stroke/MI triggered the release of neutrophil extracellular traps (NETs). Depletion of neutrophils, NET degradation or blockade of NET release inhibited the loss of IgA+ cells and circulating IgA in experimental stroke and MI and in patients with stroke. Our results unveil how tissue-injury-triggered systemic NET release disrupts physiological Ig secretion and how this can be inhibited in patients.
Assuntos
Armadilhas Extracelulares , Infarto do Miocárdio , Neutrófilos , Armadilhas Extracelulares/metabolismo , Armadilhas Extracelulares/imunologia , Humanos , Animais , Infarto do Miocárdio/imunologia , Infarto do Miocárdio/patologia , Infarto do Miocárdio/metabolismo , Masculino , Neutrófilos/imunologia , Neutrófilos/metabolismo , Feminino , Modelos Animais de Doenças , Camundongos Endogâmicos C57BL , Acidente Vascular Cerebral/imunologia , Acidente Vascular Cerebral/patologia , Acidente Vascular Cerebral/metabolismo , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/patologia , Nódulos Linfáticos Agregados/metabolismo , Imunoglobulina A/metabolismo , Imunoglobulina A/imunologia , Imunoglobulina A/sangue , Idoso , Pessoa de Meia-Idade , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Imunidade Humoral , Estudos de Casos e Controles , Camundongos , Plasmócitos/imunologia , Plasmócitos/metabolismoRESUMO
In the human and veterinary fields, oral vaccines generate considerable interest. In dogs, these vaccines are newly developed, and understanding their mechanisms is crucial. Mesenteric lymph nodes (MLNs) and Peyer's patches (PPs) are important sites for gastrointestinal mucosal induction, yet canine MLNs lack sufficient information. To address this, we collected MLN samples from healthy dogs, performed flow cytometry to characterize immune cells, and conducted single-cell RNA sequencing (scRNA-seq) to explore subpopulations, particularly B and T lymphocytes. This effort enabled the characterization of canine MLN's main cell populations and the construction of a predictive atlas, as well as the identification of particularities of this area.
Assuntos
Linfonodos , Animais , Cães , Linfonodos/metabolismo , Linfonodos/imunologia , Humanos , Camundongos , Mesentério , Linfócitos B/metabolismo , Linfócitos B/imunologia , Nódulos Linfáticos Agregados/metabolismo , Linfócitos T/imunologia , Linfócitos T/metabolismo , Análise de Célula Única , Análise de Sequência de RNA , Citometria de Fluxo , Masculino , Feminino , Análise da Expressão Gênica de Célula ÚnicaRESUMO
Immunoglobulin A (IgA)-mediated mucosal immunity is important for the host because it contributes to reducing infection risk and to establishing host-microbe symbiosis. BTB and CNC homology 1 (Bach1) is a transcriptional repressor with physiological and pathophysiological functions that are of particular interest for their relation to gastrointestinal diseases. However, Bach1 effects on IgA-mediated mucosal immunity remain unknown. For this study using Bach1-deficient (Bach1-/-) mice, we investigated the function of Bach1 in IgA-mediated mucosal immunity. Intestinal mucosa, feces, and plasma IgA were examined using immunosorbent assay. After cell suspensions were prepared from Peyer's patches and colonic lamina propria, they were examined using flow cytometry. The expression level of polymeric immunoglobulin receptor (pIgR), which plays an important role in the transepithelial transport of IgA, was evaluated using Western blotting, quantitative real-time PCR, and immunohistochemistry. Although no changes in the proportions of IgA-producing cells were observed, the amounts of IgA in the intestinal mucosa were increased in Bach1-/- mice. Furthermore, plasma IgA was increased in Bach1-/- mice, but fecal IgA was decreased, indicating that Bach1-/- mice have abnormal secretion of IgA into the intestinal lumen. In fact, Bach1 deficiency reduced pIgR expression in colonic mucosa at both the protein and mRNA levels. In the human intestinal epithelial cell line LS174T, suppression of Bach1 reduced pIgR mRNA stability. In contrast, the overexpression of Bach1 increased pIgR mRNA stability. These results demonstrate that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen via suppression of pIgR expression.NEW & NOTEWORTHY The transcriptional repressor Bach1 has been implicated in diverse intestinal functions, but the effects of Bach1 on IgA-mediated mucosal immunity remain unclear. We demonstrate here that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen, although the proportions of IgA-producing cells were not altered. Furthermore, Bach1 regulates the expression of pIgR, which plays an important role in the transepithelial transport of IgA, at the posttranscriptional level.
Assuntos
Fatores de Transcrição de Zíper de Leucina Básica , Mucosa Intestinal , Camundongos Knockout , Receptores de Imunoglobulina Polimérica , Animais , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/deficiência , Receptores de Imunoglobulina Polimérica/genética , Receptores de Imunoglobulina Polimérica/metabolismo , Mucosa Intestinal/metabolismo , Mucosa Intestinal/imunologia , Camundongos , Humanos , Imunoglobulina A/metabolismo , Imunidade nas Mucosas , Camundongos Endogâmicos C57BL , Imunoglobulina A Secretora/metabolismo , Nódulos Linfáticos Agregados/metabolismo , Nódulos Linfáticos Agregados/imunologia , Regulação da Expressão GênicaRESUMO
Introduction: Lrba is a cytoplasmic protein involved in vesicular trafficking. Lrba-deficient (Lrba-/-) mice exhibit substantially higher levels of IgA in both serum and feces than wild-type (WT) mice. Transforming growth factor ß1 (TGFß1) and its receptors (TGFßR I and II) is essential for differentiating IgA+ B cells. Furthermore, increased IgA production suggests a potential connection between Lrba and the TGFßR signaling pathway in IgA production. However, the specific function of Lrba in B cell biology remains unknown. Aim: Given the increased IgA levels in Lrba-/- mice, the goal in this work was to explore the lymph organs where the switch to IgA occurs, and if TGFßR function is affected. Methods: Non-immunized Lrba-/- mice were compared with Lrba+/+ mice. IgA levels in the serum and feces, as well as during peripheral B cell development, were determined. IgA+ B cells and plasma cells were assessed in the small intestine and secondary lymphoid organs, such as the spleen, mesenteric lymph nodes, and Peyer's patches. The TGFßR signaling pathway was evaluated by determining the expression of TGFßR on B cells. Additionally, SMAD2 phosphorylation was measured under basal conditions and in response to recombinant TGFß. Finally, confocal microscopy was performed to investigate a possible interaction between Lrba and TGFßR in B cells. Results: Lrba-/- mice exhibited significantly higher levels of circulating IgA, IgA+ B, and plasma cells than in peripheral lymphoid organs those in WT mice. TGFßR expression on the membrane of B cells was similar in both Lrba-/- and Lrba+/+ mice. However, intracellular TGFßR expression was reduced in Lrba-/- mice. SMAD2 phosphorylation showed increased levels under basal conditions; stimulation with recombinant TGFß elicited a poorer response than in that in Lrba+/+ B cells. Finally, we found that Lrba colocalizes with TGFßR in B cells. Conclusion: Lrba is essential in controlling TGFßR signaling, subsequently regulating SMAD2 phosphorylation on B cells. This mechanism may explain the increased differentiation of IgA+ B cells and production of IgA-producing plasma cells.
Assuntos
Linfócitos B , Diferenciação Celular , Imunoglobulina A , Transdução de Sinais , Animais , Camundongos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Diferenciação Celular/imunologia , Imunoglobulina A/imunologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/metabolismo , Receptores de Fatores de Crescimento Transformadores beta/genética , Proteína Smad2/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismoRESUMO
Recently, the intestinal lymphatic transport based on Peyer's patches (PPs) is emerging as a promising absorption pathway for natural polysaccharides. Herein, the aim of this study is to investigate the PP-based oral absorption of a pectic polysaccharide from Smilax china L. (SCLP), as well as its uptake and transport mechanisms in related immune cells. Taking advantages of the traceability of fluorescently labeled SCLP, we confirmed that SCLP could be absorbed into PPs and captured by their mononuclear phagocytes (dendritic cells and macrophages) following oral administration. Subsequently, the systematic in vitro study suggested that the endocytic mechanisms of SCLP by model mononuclear phagocytes (BMDCs and RAW264.7 cells) mainly involved caveolae-mediated endocytosis, macropinocytosis and phagocytosis. More importantly, SCLP directly binds and interacts with toll-like receptor 2 (TLR2) and galectin 3 (Gal-3) receptor, and was taken up by mononuclear phagocytes in receptor-mediated manner. After internalization, SCLP was intracellularly transported primarily through endolysosomal pathway and ultimately localized in lysosomes. In summary, this work reveals novel information and perspectives about the in vivo fate of SCLP, which will contribute to further research and utilization of SCLP and other pectic polysaccharides.
Assuntos
Nódulos Linfáticos Agregados , Smilax , Animais , Camundongos , Células RAW 264.7 , Nódulos Linfáticos Agregados/metabolismo , Smilax/química , Endocitose , Pectinas/química , Pectinas/metabolismo , Macrófagos/metabolismo , Macrófagos/efeitos dos fármacos , Fagocitose/efeitos dos fármacos , Fagócitos/metabolismo , Fagócitos/efeitos dos fármacos , Receptor 2 Toll-Like/metabolismo , Camundongos Endogâmicos BALB C , Masculino , Células Dendríticas/metabolismo , Células Dendríticas/efeitos dos fármacos , Administração OralRESUMO
CD200 is an anti-inflammatory protein that facilitates signal transduction through its receptor, CD200R, in cells, resulting in immune response suppression. This includes reducing M1-like macrophages, enhancing M2-like macrophages, inhibiting NK cell cytotoxicity, and downregulating CTL responses. Activation of CD200R has been found to modulate dendritic cells, leading to the induction or enhancement of Treg cells expressing Foxp3. However, the precise mechanisms behind this process are still unclear. Our previous study demonstrated that B cells in Peyer's patches can induce Treg cells, so-called Treg-of-B (P) cells, through STAT6 phosphorylation. This study aimed to investigate the role of CD200 in Treg-of-B (P) cell generation. To clarify the mechanisms, we used wild-type, STAT6 deficient, and IL-24 deficient T cells to generate Treg-of-B (P) cells, and antagonist antibodies (anti-CD200 and anti-IL-20RB), an agonist anti-CD200R antibody, CD39 inhibitors (ARL67156 and POM-1), a STAT6 inhibitor (AS1517499), and soluble IL-20RB were also applied. Our findings revealed that Peyer's patch B cells expressed CD200 to activate the CD200R on T cells and initiate the process of Treg-of-B (P) cells generation. CD200 and CD200R interaction triggers the phosphorylation of STAT6, which regulated the expression of CD200R, CD39, and IL-24 in T cells. CD39 regulated the expression of IL-24, which sustained the expression of CD223 and IL-10 and maintained the cell viability. In summary, the generation of Treg-of-B (P) cells by Peyer's patch B cells was through the CD200R-STAT6-CD39-IL-24 axis pathway.
Assuntos
Linfócitos B , Fator de Transcrição STAT6 , Linfócitos T Reguladores , Animais , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Camundongos , Linfócitos B/imunologia , Linfócitos B/metabolismo , Fator de Transcrição STAT6/metabolismo , Camundongos Endogâmicos C57BL , Receptores de Orexina/metabolismo , Receptores de Orexina/genética , Antígenos CD/metabolismo , Antígenos CD/genética , Antígenos CD/imunologia , Transdução de Sinais , Fosforilação , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Nódulos Linfáticos Agregados/citologia , Apirase/metabolismo , Apirase/imunologia , Glicoproteínas de MembranaRESUMO
Nefecon, a targeted-release capsule formulation of budesonide approved for the reduction of proteinuria in adults with primary immunoglobulin A nephropathy, targets overproduction of galactose-deficient immunoglobulin A type 1 in the Peyer's patches at the gut mucosal level. To investigate whether the commercial formulation of Nefecon capsules reliably releases budesonide to the distal ileum, a human study was conducted with test capsules reproducing the delayed-release function of Nefecon capsules. Caffeine was included in the test capsules as a marker for capsule opening in the gut since it appears rapidly in saliva after release from orally administered dosage forms. Magnetic resonance imaging with black iron oxide was used to determine the capsule's position in the gut at the time caffeine was first measured in saliva and additionally to directly visualize dispersion of the capsule contents in the gut. In vitro dissolution results confirmed that the test capsules had the same delayed-release characteristics as Nefecon capsules. In 10 of 12 human volunteers, the capsule was demonstrated to open in the distal ileum; in the other two subjects, it opened just past the ileocecal junction. These results compared favorably with the high degree of variability seen in other published imaging studies of delayed-release formulations targeting the gut. The test capsules were shown to reliably deliver their contents to the distal ileum, the region with the highest concentration of Peyer's patches.
Assuntos
Budesonida , Cápsulas , Sistemas de Liberação de Medicamentos , Íleo , Humanos , Íleo/metabolismo , Íleo/efeitos dos fármacos , Adulto , Sistemas de Liberação de Medicamentos/métodos , Masculino , Budesonida/administração & dosagem , Budesonida/farmacocinética , Budesonida/química , Feminino , Cápsulas/química , Preparações de Ação Retardada/administração & dosagem , Preparações de Ação Retardada/farmacocinética , Imageamento por Ressonância Magnética/métodos , Administração Oral , Pessoa de Meia-Idade , Cafeína/química , Cafeína/administração & dosagem , Nódulos Linfáticos Agregados/metabolismo , Nódulos Linfáticos Agregados/efeitos dos fármacos , Adulto JovemRESUMO
Induction and regulation of specific intestinal immunoglobulin (Ig)A responses critically depend on dendritic cell (DC) subsets and the T cells they activate in the Peyer's patches (PP). We found that oral immunization with cholera toxin (CT) as an adjuvant resulted in migration-dependent changes in the composition and localization of PP DC subsets with increased numbers of cluster of differentiation (CD)103- conventional DC (cDC)2s and lysozyme-expressing DC (LysoDCs) in the subepithelial dome and of CD103+ cDC2s that expressed CD101 in the T cell zones, while oral ovalbumin (OVA) tolerization was instead associated with greater accumulation of cDC1s and peripherally induced regulatory T cells (pTregs) in this area. Decreased IgA responses were observed after CT-adjuvanted immunization in huCD207DTA mice lacking CD103+ cDC2s, while oral OVA tolerization was inefficient in cDC1-deficient Batf3-/- mice. Using OVA transgenic T cell receptor CD4 T cell adoptive transfer models, we found that co-transferred endogenous wildtype CD4 T cells can hinder the induction of OVA-specific IgA responses through secretion of interleukin-10. CT could overcome this blocking effect, apparently through a modulating effect on pTregs while promoting an expansion of follicular helper T cells. The data support a model where cDC1-induced pTreg normally suppresses PP responses for any given antigen and where CT's oral adjuvanticity effect is dependent on promoting follicular helper T cell responses through induction of CD103+ cDC2s.
Assuntos
Antígenos CD , Antígeno CD11b , Movimento Celular , Toxina da Cólera , Células Dendríticas , Tolerância Imunológica , Imunização , Imunoglobulina A , Cadeias alfa de Integrinas , Camundongos Knockout , Ovalbumina , Nódulos Linfáticos Agregados , Linfócitos T Reguladores , Animais , Camundongos , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Cadeias alfa de Integrinas/metabolismo , Antígenos CD/metabolismo , Células Dendríticas/imunologia , Imunoglobulina A/imunologia , Imunoglobulina A/metabolismo , Administração Oral , Toxina da Cólera/imunologia , Ovalbumina/imunologia , Ovalbumina/administração & dosagem , Linfócitos T Reguladores/imunologia , Antígeno CD11b/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Camundongos Transgênicos , Camundongos Endogâmicos C57BL , Transferência Adotiva , Proteínas RepressorasRESUMO
Peyer's patches (PPs) are part of the gut-associated lymphatic tissue (GALT) and represent the first line of the intestinal immunological defense. They consist of follicles with lymphocytes and an overlying subepithelial dome with dendritic cells and macrophages, and they are covered by the follicle-associated epithelium (FAE). A sealed paracellular pathway in the FAE is crucial for the controlled uptake of luminal antigens. Quercetin is the most abundant plant flavonoid and has a barrier-strengthening effect on tight junctions (TJs), a protein complex that regulates the paracellular pathway. In this study, we aimed to analyze the effect of quercetin on porcine PPs and the surrounding villus epithelium (VE). We incubated both tissue types for 4 h in Ussing chambers, recorded the transepithelial electrical resistance (TEER), and measured the unidirectional tracer flux of [3H]-mannitol. Subsequently, we analyzed the expression, protein amount, and localization of three TJ proteins, claudin 1, claudin 2, and claudin 4. In the PPs, we could not detect an effect of quercetin after 4 h, neither on TEER nor on the [3H]-mannitol flux. In the VE, quercetin led to a higher TEER value, while the [3H]-mannitol flux was unchanged. The pore-forming claudin 2 was decreased while the barrier-forming claudin 4 was increased and the expression was upregulated. Claudin 1 was unchanged and all claudins could be located in the paracellular membrane by immunofluorescence microscopy. Our study shows the barrier-strengthening effect of quercetin in porcine VE by claudin 4 upregulation and a claudin 2 decrease. Moreover, it underlines the different barrier properties of PPs compared to the VE.
Assuntos
Nódulos Linfáticos Agregados , Quercetina , Animais , Suínos , Quercetina/farmacologia , Quercetina/metabolismo , Nódulos Linfáticos Agregados/metabolismo , Claudina-4/metabolismo , Claudina-2/metabolismo , Claudina-1/metabolismo , Intestino Delgado/metabolismo , Claudinas/metabolismo , Junções Íntimas/metabolismo , Manitol/farmacologiaRESUMO
Butyrophilin-like 2 (BTNL2) is a T cell inhibitory molecule that interacts with unknown binding partners to modulate the immune response in a number of inflammatory and autoimmune diseases. In this study, we found that the inhibitory effects of BTNL2 on T cell activation and effector functions can be executed by its N-terminal IgV domain (BTNL2 IgV1) alone. Structure-guided mutation of key residues on BTNL2 IgV1 based on known receptor-ligand interfaces involving immunoglobulin superfamily members revealed that BTNL2 uses a non-canonical binding interface with its putative receptor. A high avidity BTNL2 IgV1 probe revealed that in an inducible model of ulcerative colitis, severe colitis was accompanied by a selective enrichment of BTNL2-receptor expressing effector-memory CD4+ and CD8+ T cells in the Peyer's patches. Intraperitoneal administration of BTNL2 IgV1 resulted in a significant delay in the progression of DSS-induced colitis and also showed reduced activation of the BTNL2-receptor-expressing T cells in the Peyer's patches. Thus, this study demonstrates that the BTNL2-receptor-expressing T cells in the Peyer's patches participate in the disease pathogenesis and can serve as a novel therapeutic target in ulcerative colitis, which can be modulated by BTNL2 IgV1.
Assuntos
Colite Ulcerativa , Colite , Butirofilinas/metabolismo , Linfócitos T CD8-Positivos , Colite Ulcerativa/induzido quimicamente , Nódulos Linfáticos Agregados/metabolismo , AnimaisRESUMO
The dysregulation of B cell maturation and putrescine metabolism has been implicated in various diseases. However, the causal relationship between them and the underlying mechanisms remain unclear. In this study, we investigated the impact of exogenous putrescine on B cell differentiation in the intestinal microenvironment. Our results demonstrated that administration of exogenous putrescine significantly impaired the proportion of germinal center B (GC B) cells in Peyer's patches (PPs) and lamina propria. Through integration of bulk RNA sequencing and single-cell RNA sequencing (scRNA-seq), we identified putrescine-mediated changes in gene drivers, including those involved in the B cell receptor (BCR) signaling pathway and fatty acid oxidation. Furthermore, putrescine drinking disrupted T-B cell interactions and increased reactive oxygen species (ROS) production in B cells. In vitro activation of B cells confirmed the direct suppression of putrescine on GC B cells differentiation and ROS production. Additionally, we explored the Pearson correlations between putrescine biosynthesis activity and B cell infiltration in pan-cancers, revealing negative correlations in colon adenocarcinoma, stomach adenocarcinoma, and lung adenocarcinoma, but positive correlations in liver hepatocellular carcinoma, and breast invasive carcinoma. Our findings provided novel insights into the suppressive effects of elevated enteric putrescine on intestinal B cells differentiation and highlighted the complex and distinctive immunoregulatory role of putrescine in different microenvironments. These findings expand our understanding of the role of polyamines in B cell immunometabolism and related diseases.
Assuntos
Adenocarcinoma , Neoplasias do Colo , Humanos , Putrescina/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Adenocarcinoma/metabolismo , Nódulos Linfáticos Agregados/metabolismo , Neoplasias do Colo/metabolismo , Centro Germinativo , Diferenciação Celular , Microambiente TumoralRESUMO
In light of the demonstrated antagonism of Wnt5A signaling toward the growth of several bacterial pathogens, it was important to study the influence of Wnt5A on gut-resident bacteria and its outcome. Here, we demonstrate that in contrast to inhibiting the survival of the established gut pathogen Salmonella enterica, Wnt5A clearly promotes the survival of the common gut commensals Enterococcus faecalis and Lactobacillus rhamnosus within macrophages through a self-perpetuating Wnt5A-actin axis. A Wnt5A-actin axis furthermore regulates the subsistence of the natural bacterial population of the Peyer's patches, as is evident from the diminution in the countable bacterial CFU therein through the application of Wnt5A signaling and actin assembly inhibitors. Wnt5A dependency of the gut-resident bacterial population is also manifested in the notable difference between the bacterial diversities associated with the feces and Peyer's patches of Wnt5A heterozygous mice, which lack a functional copy of the Wnt5A gene, and their wild-type counterparts. Alterations in the gut commensal bacterial population resulting from either the lack of a copy of the Wnt5A gene or inhibitor-mediated attenuation of Wnt5A signaling are linked with significant differences in cell surface major histocompatibility complex (MHC) II levels and regulatory versus activated CD4 T cells associated with the Peyer's patches. Taken together, our findings reveal the significance of steady state Wnt5A signaling in shaping the gut commensal bacterial population and the T cell repertoire linked to it, thus unveiling a crucial control device for the maintenance of gut bacterial diversity and T cell homeostasis. IMPORTANCE Gut commensal bacterial diversity and T cell homeostasis are crucial entities of the host innate immune network, yet the molecular details of host-directed signaling pathways that sustain the steady state of gut bacterial colonization and T cell activation remain unclear. Here, we describe the protective role of a Wnt5A-actin axis in the survival of several gut bacterial commensals and its necessity in shaping gut bacterial colonization and the associated T cell repertoire. This study opens up new avenues of investigation into the role of the Wnt5A-actin axis in protection of the gut from dysbiosis-related inflammatory disorders.
Assuntos
Microbioma Gastrointestinal , Nódulos Linfáticos Agregados , Camundongos , Animais , Nódulos Linfáticos Agregados/metabolismo , Actinas/metabolismo , Bactérias , HomeostaseRESUMO
Lymphocytes can heavily influence intestinal health, but resolving intestinal lymphocyte function is challenging as the intestine contains a vastly heterogeneous mixture of cells. Pigs are an advantageous biomedical model, but deeper understanding of intestinal lymphocytes is warranted to improve model utility. Twenty-six cell types were identified in the porcine ileum by single-cell RNA sequencing and further compared with cells in human and murine ileum. Though general consensus of cell subsets across species was revealed, some porcine-specific lymphocyte subsets were identified. Differential tissue dissection and in situ analyses conferred spatial context, revealing similar locations of lymphocyte subsets in Peyer's patches and epithelium in pig-to-human comparisons. Like humans, activated and effector lymphocytes were abundant in the ileum but not periphery of pigs, suggesting tissue-specific and/or activation-associated gene expression. Gene signatures for peripheral and ileal innate lymphoid cells newly discovered in pigs were defined and highlighted similarities to human innate lymphoid cells. Overall, we reveal novel lymphocyte subsets in pigs and highlight utility of pigs for intestinal research applications.
Assuntos
Linfócitos , Nódulos Linfáticos Agregados , Animais , Humanos , Íleo/metabolismo , Imunidade Inata , Intestinos , Camundongos , Nódulos Linfáticos Agregados/metabolismo , SuínosRESUMO
OBJECTIVE: The aim: The aim of the study is to experimentally test the process of viral infection and determine the ways of its penetration into the human body. PATIENTS AND METHODS: Materials and methods: This experimental analysis is based on systematic research, published peer-reviewed articles, books, textbooks, monographs. It should also be noted that in order to identify some immunocompetent lymph node cells and the ability to visualize certain sites in the lymphoid nodes of Peyer's patches, where the initial processes are presented below, we resorted to sampling anatomical material. The study involved 10 adult albino rats weighing 200.0 ± 20.0 g. The search period covered the period from 2010 to 2021, but the experimental analysis contains some valuable data from previous years, as these literature sources have significant scientific value. RESULTS: Results: According to immunohistochemical analysis of the epithelium associated with the dome of the lymph nodes of the small intestine of white rats, the bulk was B-lymphocytes (about 47%) and T-lymphocytes (about 35%), while plasma cells, macrophages and dendritic cells accounted for approximately 5% for each of them. CONCLUSION: Conclusions: Ð rocess of development of viral infection can be represented in the form of the following targeted steps: 1) massive invasion of viruses into the body; 2) the pathway of viruses to the intended target (target cells) is carried out by the blood flow; 3) аchieving the target by viruses and their penetration into target cells. Ðn the pathogenesis of viral diseases, the role is played by the preparedness of the particular body, which directly depends on the functional state of its immune system, which determines the possibility, severity and outcome of the disease.
Assuntos
Nódulos Linfáticos Agregados , Viroses , Humanos , Ratos , Corpo Humano , Intestino Delgado , Linfonodos , Nódulos Linfáticos Agregados/metabolismo , AnimaisRESUMO
Gut-associated lymphoid tissue (GALT), such as Peyer's patches (PPs), are key inductive sites that generate IgA+ B cells, mainly through germinal center (GC) responses. The generation of IgA+ B cells is promoted by the presence of gut microbiota and dietary antigens. However, the function of GALT in the large intestine, such as cecal patches (CePs) and colonic patches (CoPs), and their regulatory mechanisms remain largely unknown. In this study, we demonstrate that the CePs possess more IgG2b+ B cells and have fewer IgA+ B cells than those in PPs from BALB/c mice with normal gut microbiota. Gene expression analysis of postswitched transcripts supported the differential expression of dominant antibody isotypes in B cells in GALT. Germ-free (GF) mice showed diminished GC B cells and had few IgA+ or IgG2b+ switched B cells in both the small and large intestinal GALT. In contrast, myeloid differentiation factor 88- (MyD88-) deficient mice exhibited decreased GC B cells and presented with reduced numbers of IgG2b+ B cells in CePs but not in PPs. Using ex vivo cell culture, we showed that CePs have a greater capacity to produce total and microbiota-reactive IgG2b, in addition to microbiota-reactive IgA, than the PPs. In line with the frequency of GC B cells and IgG2b+ B cells in CePs, there was a decrease in the levels of microbiota-reactive IgG2b and IgA in the serum of GF and MyD88-deficient mice. These data suggest that CePs have a different antibody production profile compared to PPs. Furthermore, the innate immune signals derived from gut microbiota are crucial for generating the IgG2b antibodies in CePs.
Assuntos
Microbioma Gastrointestinal , Nódulos Linfáticos Agregados , Animais , Imunoglobulina A/metabolismo , Imunoglobulina G/metabolismo , Camundongos , Fator 88 de Diferenciação Mieloide/metabolismo , Nódulos Linfáticos Agregados/metabolismoRESUMO
Fumonisin B1 (FB1) is a widespread mycotoxin produced by fungal Fusarium species-mainly in maize, one of the plants most commonly used for food and feed. Pigs and horses are the animal species most susceptible to this mycotoxin. FB1 exposure can cause highly diverse clinical symptoms, including hepatotoxicity, immunotoxicity, and intestinal barrier function disturbance. Inhibition of ceramide synthetase is a well-understood ubiquitous molecular mechanism of FB1 toxicity, but other more tissue-specific effects remain to be elucidated. To investigate the effects of FB1 in different exposed tissues, we cross-analyzed the transcriptomes of fours organs: liver, jejunum, jejunal Peyer's patches, and spleen. During a four-week study period, pigs were fed a control diet or a FB1-contaminated diet (10 mg/kg feed). In response to oral FB1 exposure, we observed common biological processes in the four organs, including predominant and recurrent processes (extracellular matrix organization, integrin activation, granulocyte chemotaxis, neutrophil migration, and lipid and sterol homeostasis), as well as more tissue-specific processes that appeared to be related to lipid outcomes (cell cycle regulation in jejunum, and gluconeogenesis in liver).
Assuntos
Fumonisinas/toxicidade , Regulação da Expressão Gênica/efeitos dos fármacos , Doenças dos Suínos/induzido quimicamente , Administração Oral , Animais , Estudo de Associação Genômica Ampla , Jejuno/efeitos dos fármacos , Jejuno/metabolismo , Fígado/efeitos dos fármacos , Fígado/metabolismo , Nódulos Linfáticos Agregados/efeitos dos fármacos , Nódulos Linfáticos Agregados/metabolismo , SuínosRESUMO
The mucosal immune system is the first line of defense against pathogens. Germinal centers (GCs) in the Peyer's patches (PPs) of the small intestine are constantly generated through stimulation of the microbiota. In this study, we investigated the role of γδ T cells in the GC reactions in PPs. Most γδ T cells in PPs localized in the GCs and expressed a TCR composed of Vγ1 and Vδ6 chains. By using mice with partial and total γδ T cell deficiencies, we found that Vγ1+/Vδ6+ T cells can produce high amounts of IL-4, which drives the proliferation of GC B cells as well as the switch of GC B cells towards IgA. Therefore, we conclude that γδ T cells play a role in sustaining gut homeostasis and symbiosis via supporting the GC reactions in PPs.
Assuntos
Linfócitos B/metabolismo , Centro Germinativo/metabolismo , Interleucina-4/metabolismo , Mucosa Intestinal/metabolismo , Linfócitos Intraepiteliais/metabolismo , Nódulos Linfáticos Agregados/metabolismo , Receptores de Antígenos de Linfócitos T gama-delta/metabolismo , Animais , Linfócitos B/imunologia , Linfócitos B/microbiologia , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Modelos Animais de Doenças , Centro Germinativo/imunologia , Centro Germinativo/microbiologia , Imunidade nas Mucosas , Imunoglobulina A/imunologia , Imunoglobulina A/metabolismo , Switching de Imunoglobulina , Mucosa Intestinal/imunologia , Mucosa Intestinal/microbiologia , Linfócitos Intraepiteliais/imunologia , Linfócitos Intraepiteliais/microbiologia , Ativação Linfocitária , Depleção Linfocítica , Camundongos Knockout , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/microbiologia , Fenótipo , Receptores de Antígenos de Linfócitos T gama-delta/genética , Receptores de Antígenos de Linfócitos T gama-delta/imunologia , Infecções por Salmonella/imunologia , Infecções por Salmonella/metabolismo , Infecções por Salmonella/microbiologia , Salmonella typhimurium/imunologia , Salmonella typhimurium/patogenicidade , Transdução de SinaisRESUMO
Diets high in cholesterol alter intestinal immunity. Here, we examined how the cholesterol metabolite 25-hydroxycholesterol (25-HC) impacts the intestinal B cell response. Mice lacking cholesterol 25-hydroxylase (CH25H), the enzyme generating 25-HC, had higher frequencies of immunoglobulin A (IgA)-secreting antigen-specific B cells upon immunization or infection. 25-HC did not affect class-switch recombination but rather restrained plasma cell (PC) differentiation. 25-HC was produced by follicular dendritic cells and increased in response to dietary cholesterol. Mechanistically, 25-HC restricted activation of the sterol-sensing transcription factor SREBP2, thereby regulating B cell cholesterol biosynthesis. Ectopic expression of SREBP2 in germinal center B cells induced rapid PC differentiation, whereas SREBP2 deficiency reduced PC output in vitro and in vivo. High-cholesterol diet impaired, whereas Ch25h deficiency enhanced, the IgA response against Salmonella and the resulting protection from systemic bacterial dissemination. Thus, a 25-HC-SREBP2 axis shapes the humoral response at the intestinal barrier, providing insight into the effect of high dietary cholesterol in intestinal immunity.
Assuntos
Diferenciação Celular/imunologia , Hidroxicolesteróis/metabolismo , Imunoglobulina A/imunologia , Plasmócitos/imunologia , Proteína de Ligação a Elemento Regulador de Esterol 2/metabolismo , Animais , Colesterol na Dieta/imunologia , Colesterol na Dieta/metabolismo , Hidroxicolesteróis/imunologia , Imunoglobulina A/metabolismo , Mucosa Intestinal/imunologia , Mucosa Intestinal/metabolismo , Camundongos , Nódulos Linfáticos Agregados/imunologia , Nódulos Linfáticos Agregados/metabolismo , Plasmócitos/metabolismoRESUMO
Intestinal microfold cells (M cells) are a dynamic lineage of epithelial cells that initiate mucosal immunity in the intestine. They are responsible for the uptake and transcytosis of microorganisms, pathogens, and other antigens in the gastrointestinal tract. A mature M cell expresses a receptor Gp2 which binds to pathogens and aids in the uptake. Due to the rarity of these cells in the intestine, their development and differentiation remain yet to be fully understood. We recently demonstrated that polycomb repressive complex 2 (PRC2) is an epigenetic regulator of M cell development, and 12 novel transcription factors including Atoh8 were revealed to be regulated by the PRC2. Here, we show that Atoh8 acts as a regulator of M cell differentiation; the absence of Atoh8 led to a significant increase in the number of Gp2+ mature M cells and other M cell-associated markers such as Spi-B and Sox8. In vitro organoid analysis of RankL treated organoid showed an increase of mature marker GP2 expression and other M cell-associated markers. Atoh8 null mice showed an increase in transcytosis capacity of luminal antigens. An increase in M cell population has been previously reported to be detrimental to mucosal immunity because some pathogens like orally acquired prions have been able to exploit the transcytosis capacity of M cells to infect the host; mice with an increased population of M cells are also susceptible to Salmonella infections. Our study here demonstrates that PRC2 regulated Atoh8 is one of the factors that regulate the population density of intestinal M cell in the Peyer's patch.