RESUMEN
Type I interferons (IFNs) exert a broad range of biological effects important in coordinating immune responses, which have classically been studied in the context of pathogen clearance. Yet, whether immunomodulatory bacteria operate through IFN pathways to support intestinal immune tolerance remains elusive. Here, we reveal that the commensal bacterium, Bacteroides fragilis, utilizes canonical antiviral pathways to modulate intestinal dendritic cells (DCs) and regulatory T cell (Treg) responses. Specifically, IFN signaling is required for commensal-induced tolerance as IFNAR1-deficient DCs display blunted IL-10 and IL-27 production in response to B. fragilis. We further establish that IFN-driven IL-27 in DCs is critical in shaping the ensuing Foxp3+ Treg via IL-27Rα signaling. Consistent with these findings, single-cell RNA sequencing of gut Tregs demonstrated that colonization with B. fragilis promotes a distinct IFN gene signature in Foxp3+ Tregs during intestinal inflammation. Altogether, our findings demonstrate a critical role of commensal-mediated immune tolerance via tonic type I IFN signaling.
Asunto(s)
Interferón Tipo I , Interleucina-27 , Ratones , Animales , Interleucina-27/metabolismo , Linfocitos T Reguladores , Interferón Tipo I/metabolismo , Tolerancia Inmunológica , Factores de Transcripción Forkhead/metabolismo , Bacterias/metabolismo , Células DendríticasRESUMEN
Regulatory T cells (Treg cells) are instrumental in establishing immunological tolerance. However, the precise effector mechanisms by which Treg cells control a specific type of immune response in a given tissue remains unresolved. By simultaneously studying Treg cells from different tissue origins under systemic autoimmunity, in the present study we show that interleukin (IL)-27 is specifically produced by intestinal Treg cells to regulate helper T17 cell (TH17 cell) immunity. Selectively increased intestinal TH17 cell responses in mice with Treg cell-specific IL-27 ablation led to exacerbated intestinal inflammation and colitis-associated cancer, but also helped protect against enteric bacterial infection. Furthermore, single-cell transcriptomic analysis has identified a CD83+CD62Llo Treg cell subset that is distinct from previously characterized intestinal Treg cell populations as the main IL-27 producers. Collectively, our study uncovers a new Treg cell suppression mechanism crucial for controlling a specific type of immune response in a particular tissue and provides further mechanistic insights into tissue-specific Treg cell-mediated immune regulation.
Asunto(s)
Interleucina-27 , Linfocitos T Reguladores , Ratones , Animales , Linfocitos T Colaboradores-Inductores , Tolerancia Inmunológica , Inmunidad Celular , Células Th17RESUMEN
Mucosal-associated invariant T (MAIT) cells are a subset of T lymphocytes that respond to microbial metabolites. We defined MAIT cell populations in different organs and characterized the developmental pathway of mouse and human MAIT cells in the thymus using single-cell RNA sequencing and phenotypic and metabolic analyses. We showed that the predominant mouse subset, which produced IL-17 (MAIT17), and the subset that produced IFN-γ (MAIT1) had not only greatly different transcriptomes but also different metabolic states. MAIT17 cells in different organs exhibited increased lipid uptake, lipid storage, and mitochondrial potential compared with MAIT1 cells. All these properties were similar in the thymus and likely acquired there. Human MAIT cells in lung and blood were more homogeneous but still differed between tissues. Human MAIT cells had increased fatty acid uptake and lipid storage in blood and lung, similar to human CD8 T resident memory cells, but unlike mouse MAIT17 cells, they lacked increased mitochondrial potential. Although mouse and human MAIT cell transcriptomes showed similarities for immature cells in the thymus, they diverged more strikingly in the periphery. Analysis of pet store mice demonstrated decreased lung MAIT17 cells in these so-called "dirty" mice, indicative of an environmental influence on MAIT cell subsets and function.
Asunto(s)
Células T Invariantes Asociadas a Mucosa , Humanos , Transcriptoma , Linfocitos T CD8-positivos , Timo , LípidosRESUMEN
Effector regulatory T cells (eTregs) exhibit distinct homeostatic properties and superior suppressor capacities pivotal for controlling immune responses mediated by their conventional T cell counterpart. While the role of microRNAs (miRNAs) in Tregs has been well-established, how miRNAs regulate eTregs remains poorly understood. Here, we demonstrate that miR-15/16 clusters act as key regulators in limiting eTreg responses. Loss of miR-15/16 clusters leads to increased eTreg frequencies with enhanced suppressor function. Consequently, mice with Treg-specific ablation of miR-15/16 clusters display attenuated immune responses during neuroinflammation and upon both infectious and non-infectious challenges. Mechanistically, miR-15/16 clusters exert their regulatory effect in part through repressing IRF4, a transcription factor essential for eTreg differentiation and function. Moreover, miR-15/16 clusters also directly target neuritin, an IRF4-dependent molecule, known for its role in Treg-mediated regulation of plasma cell responses. Together, we identify an miRNA family that controls an important Treg subset and further demonstrate that eTreg responses are tightly regulated at both transcriptional and posttranscriptional levels.
Asunto(s)
MicroARNs , Linfocitos T Reguladores , Animales , Ratones , Activación de Linfocitos , Diferenciación Celular/genética , Homeostasis , MicroARNs/genéticaRESUMEN
Regulatory T (Treg) cells are instrumental in establishing immunological tolerance. However, the precise effector mechanisms by which Treg cells control a specific type of immune response in a given tissue remains unresolved. By simultaneously studying Treg cells from different tissue origins under systemic autoimmunity, here we show that IL-27 is specifically produced by intestinal Treg cells to regulate Th17 immunity. Selectively increased intestinal Th17 responses in mice with Treg cell-specific IL-27 ablation led to exacerbated intestinal inflammation and colitis-associated cancer, but also helped protect against enteric bacterial infection. Furthermore, single-cell transcriptomic analysis has identified a CD83+TCF1+ Treg cell subset that is distinct from previously characterized intestinal Treg cell populations as the main IL-27 producers. Collectively, our study uncovers a novel Treg cell suppression mechanism crucial for controlling a specific type of immune response in a particular tissue, and provides further mechanistic insights into tissue-specific Treg cell-mediated immune regulation.
RESUMEN
Gut dysbiosis has long been associated with the development of Crohn's disease and other gastrointestinal disorders. Otake-Kasamoto et al. (2022. J. Exp. Med.https://doi.org/10.1084/jem.20211291) report that dysbiotic microbiota-derived bioactive lipids, lysophosphatidylserines, can promote pathological Th1 cell responses through inducing metabolic reprogramming and epigenetic changes.
Asunto(s)
Microbioma Gastrointestinal , Microbiota , Disbiosis , Microbioma Gastrointestinal/fisiología , HumanosRESUMEN
IL-27 controls a diverse range of immune responses in many disease settings. Here, we identify intestinal epithelial cells (IECs) as one of the major IL-27 cellular sources in the gut-associated tissue. Unlike IL-27 secreted by innate immune cells, gut epithelial IL-27 is dispensable for T-bet+ regulatory T cell (T reg cell) differentiation or IL-10 induction. Rather, IEC-derived IL-27 specifically promotes a distinct CD8αα+CD4+ intraepithelial lymphocyte (IEL) population that acquires their functional differentiation at the intestinal epithelium. Loss of IL-27 in IECs leads to a selective defect in CD8αα+CD4+ IELs over time. Consequently, mice with IEC-specific IL-27 ablation exhibited elevated pathogen burden during parasitic infection, and this could be rescued by transfer of exogenous CD8αα+CD4+ IELs. Collectively, our data reveal that in addition to its known regulatory properties in preventing immune hyperactivity, gut epithelial IL-27 confers barrier immunity by inducing a specific IEL subset and further suggest that IL-27 produced by different cell types plays distinct roles in maintaining intestinal homeostasis.
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Células Epiteliales/inmunología , Interleucinas/inmunología , Mucosa Intestinal/inmunología , Linfocitos Intraepiteliales/inmunología , Animales , Linfocitos T CD4-Positivos/inmunología , Antígenos CD8/inmunología , Linfocitos T CD8-positivos/inmunología , Diferenciación Celular/inmunología , Femenino , Homeostasis/inmunología , Masculino , Ratones , Ratones Noqueados , Receptores de Antígenos de Linfocitos T alfa-beta/inmunología , Transducción de Señal/inmunologíaRESUMEN
T cells are crucial to generate an effective response against numerous invading microbial pathogens and play a pivotal role in tumor surveillance and elimination. However, unwanted T cell activation can also lead to deleterious immune-mediated inflammation and tissue damage. To ensure that an optimal T cell response can be established, each step, beginning from T cell development in the thymus to their activation and function in the periphery, is tightly regulated by many transcription factors and epigenetic regulators including microRNAs (miRNAs). Here, we first summarize recent progress in identifying major immune regulatory miRNAs in controlling the differentiation and function of distinct T cell subsets. Moreover, as emerging evidence has demonstrated that miRNAs can impact T cell immunity through targeting both immune- and non-immune cell populations that T cells closely interact with, the T cell-extrinsic role of miRNAs in regulating different aspects of T cell biology is also addressed. Finally, we discuss the complex nature of miRNA-mediated control of T cell immunity and highlight important questions that remain to be further investigated.
Asunto(s)
MicroARNs , Diferenciación Celular , Humanos , Inflamación , Activación de Linfocitos , MicroARNs/genética , Subgrupos de Linfocitos TRESUMEN
IL30mRNA expression is associated with the TNBC subtype. IL30 boosts proliferation and migration of TNBC cells and reshapes their immunity gene expression profile. The lack of endogenous IL30 hinders TNBC growth and progression and prolongs host survival. TNBC growth inhibition, due to the lack of endogenous IL30, requires INFγ production by T and NK cells.
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Proliferación Celular/fisiología , Interferón gamma/inmunología , Interleucinas/inmunología , Transducción de Señal/inmunología , Neoplasias de la Mama Triple Negativas/inmunología , Neoplasias de la Mama Triple Negativas/patología , Animales , Línea Celular Tumoral , Modelos Animales de Enfermedad , Progresión de la Enfermedad , RatonesRESUMEN
During thymocyte development, medullary thymic epithelial cells (mTECs) provide appropriate instructive cues in the thymic microenvironment for not only negative selection but also the generation of regulatory T (T reg) cells. Here, we identify that miR-155, a microRNA whose expression in T reg cells has previously been shown to be crucial for their development and homeostasis, also contributes to thymic T reg (tT reg) cell differentiation by promoting mTEC maturation. Mechanistically, we show that RANKL stimulation induces expression of miR-155 to safeguard the thymic medulla through targeting multiple known and previously uncharacterized molecules within the TGFß signaling pathway, which is recognized for its role in restricting the maturation and expansion of mTECs. Our work uncovers a miR-155-TGFß axis in the thymic medulla to determine mTEC maturity and, consequently, the quantity of tT reg cells and suggests that miR-155 ensures proper tT reg cell development in both cell-intrinsic and -extrinsic manners.
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Células Epiteliales/inmunología , MicroARNs/inmunología , Linfocitos T Reguladores/inmunología , Timo/inmunología , Animales , Diferenciación Celular/inmunología , Activación de Linfocitos/inmunología , Ratones , Ratones Noqueados , Transducción de Señal/inmunología , Factor de Crecimiento Transformador beta/inmunologíaRESUMEN
Inflammatory bowel disease (IBD) encompasses a spectrum of gastrointestinal disorders driven by dysregulated immune responses against gut microbiota. We integrated single-cell RNA and antigen receptor sequencing to elucidate key components, cellular states, and clonal relationships of the peripheral and gastrointestinal mucosal immune systems in health and ulcerative colitis (UC). UC was associated with an increase in IgG1+ plasma cells in colonic tissue, increased colonic regulatory T cells characterized by elevated expression of the transcription factor ZEB2, and an enrichment of a γδ T cell subset in the peripheral blood. Moreover, we observed heterogeneity in CD8+ tissue-resident memory T (TRM) cells in colonic tissue, with four transcriptionally distinct states of differentiation observed across health and disease. In the setting of UC, there was a marked shift of clonally related CD8+ TRM cells toward an inflammatory state, mediated, in part, by increased expression of the T-box transcription factor Eomesodermin. Together, these results provide a detailed atlas of transcriptional changes occurring in adaptive immune cells in the context of UC and suggest a role for CD8+ TRM cells in IBD.
Asunto(s)
Colitis Ulcerosa/inmunología , Linfocitos Intraepiteliales/inmunología , Células T de Memoria/inmunología , Linfocitos T Reguladores/inmunología , Inmunidad Adaptativa , Animales , Colon/inmunología , Humanos , Inmunoglobulina G/inmunología , Masculino , Ratones Transgénicos , Análisis de la Célula IndividualRESUMEN
In this study, we investigated the biophysical interaction between cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and CD80. CTLA-4 is a key molecule in immunosuppression, and CD80 is a costimulatory receptor promoting T cell activation. We observed that after cell-cell contact was established between breast cancer cells and antigen presenting cells (APCs), CTLA-4 expressed on the breast cancer cells bind to CD80 expressed on the APCs, and underwent trans-endocytosis to deplete CD80. Force measurement and live cell imaging revealed that upon binding to CD80, forces generated by breast cancer cells and transmitted via CTLA-4 were sufficiently strong to displace CD80 from the surface of APCs to be internalized by breast cancer cells. We further demonstrated that because of the force-dependent trans-endocytosis of CD80, the capacity of APCs to activate T cells was significantly attenuated. Furthermore, inhibiting force generation in cancer cells would increase the T cell activating capacity of APCs. Our results provide a possible mechanism behind the immunosuppression commonly seen in breast cancer patients, and may lead to a new strategy to restore anti-tumor immunity by inhibiting pathways of force-generation.
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Técnicas Biosensibles , Neoplasias de la Mama , Antígeno B7-2 , Antígenos CD28 , Endocitosis , Humanos , Activación de Linfocitos , Linfocitos TRESUMEN
The development of cancer is a complex and dynamically regulated multiple-step process that involves many changes in gene expression. Over the last decade, microRNAs (miRNAs), a class of short regulatory non-coding RNAs, have emerged as key molecular effectors and regulators of tumorigenesis. While aberrant expression of miRNAs or dysregulated miRNA-mediated gene regulation in tumor cells have been shown to be capable of directly promoting or inhibiting tumorigenesis, considering the well-reported role of the immune system in cancer, tumor-derived miRNAs could also impact tumor growth through regulating anti-tumor immune responses. Here, we discuss howmiRNAs can function as central mediators that influence the crosstalk between cancer and the immune system. Moreover, we also review the current progress in the development of novel experimental approaches for miRNA target identification that will facilitate our understanding of miRNA-mediated gene regulation in not only human malignancies, but also in other genetic disorders.
RESUMEN
Follicular helper T (TFH) cells are essential for generating protective humoral immunity. To date, microRNAs (miRNAs) have emerged as important players in regulating TFH cell biology. Here, we show that loss of miR-23~27~24 clusters in T cells resulted in elevated TFH cell frequencies upon different immune challenges, whereas overexpression of this miRNA family led to reduced TFH cell responses. Mechanistically, miR-23~27~24 clusters coordinately control TFH cells through targeting a network of genes that are crucial for TFH cell biology. Among them, thymocyte selection-associated HMG-box protein (TOX) was identified as a central transcription regulator in TFH cell development. TOX is highly up-regulated in both mouse and human TFH cells in a BCL6-dependent manner. In turn, TOX promotes the expression of multiple molecules that play critical roles in TFH cell differentiation and function. Collectively, our results establish a key miRNA regulon that maintains optimal TFH cell responses for resultant humoral immunity.
Asunto(s)
Diferenciación Celular/genética , Inmunidad Humoral/genética , Linfocitos T Colaboradores-Inductores/inmunología , Linfocitos T/inmunología , Animales , Regulación del Desarrollo de la Expresión Génica/inmunología , Proteínas del Grupo de Alta Movilidad/genética , Humanos , Inmunidad Humoral/inmunología , Activación de Linfocitos/inmunología , Ratones , MicroARNs/genética , Proteínas Proto-Oncogénicas c-bcl-6/genética , Transducción de Señal , Linfocitos T Colaboradores-Inductores/metabolismoRESUMEN
Combined immunotherapy targeting the immune checkpoint receptors cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death 1 (PD-1), or CTLA-4 and the PD-1 ligand (PD-L1) exhibits superior anti-tumor responses compared with single-agent therapy. Here, we examined the molecular basis for this synergy. Using reconstitution assays with fluorescence readouts, we found that PD-L1 and the CTLA-4 ligand CD80 heterodimerize in cis but not trans. Quantitative biochemistry and cell biology assays revealed that PD-L1:CD80 cis-heterodimerization inhibited both PD-L1:PD-1 and CD80:CTLA-4 interactions through distinct mechanisms but preserved the ability of CD80 to activate the T cell co-stimulatory receptor CD28. Furthermore, PD-L1 expression on antigen-presenting cells (APCs) prevented CTLA-4-mediated trans-endocytosis of CD80. Atezolizumab (anti-PD-L1), but not anti-PD-1, reduced cell surface expression of CD80 on APCs, and this effect was negated by co-blockade of CTLA-4 with ipilimumab (anti-CTLA-4). Thus, PD-L1 exerts an immunostimulatory effect by repressing the CTLA-4 axis; this has implications to the synergy of anti-PD-L1 and anti-CTLA-4 combination therapy.
Asunto(s)
Antígeno B7-1/metabolismo , Antígeno B7-H1/metabolismo , Antígenos CD28/metabolismo , Antígeno CTLA-4/antagonistas & inhibidores , Receptor de Muerte Celular Programada 1/antagonistas & inhibidores , Animales , Anticuerpos Monoclonales Humanizados/farmacología , Antineoplásicos/farmacología , Línea Celular Tumoral , Femenino , Células HEK293 , Humanos , Inmunoterapia/métodos , Ipilimumab/farmacología , Células Jurkat , Activación de Linfocitos , Ratones , Ratones Endogámicos BALB C , Neoplasias/inmunología , Neoplasias/terapia , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunologíaRESUMEN
Gut homeostasis is maintained by dynamic host-microbiota interactions. Recently, miRNAs have emerged as key molecular regulators in the mediation of such interactions. Here, we discuss the role of a host miRNA-microbiome axis in gut homeostasis and colorectal cancer (CRC) and the involvement of diet and microbial metabolites in miRNA-mediated intestinal health.
Asunto(s)
Neoplasias Colorrectales/genética , Neoplasias Colorrectales/microbiología , Microbioma Gastrointestinal/genética , MicroARNs , Dieta , Homeostasis , HumanosRESUMEN
BACKGROUND: Interleukin(IL)-30/IL-27p28 production by Prostate Cancer (PC) Stem-Like Cells (SLCs) has proven, in murine models, to be critical to tumor onset and progression. In PC patients, IL-30 expression by leukocytes infiltrating PC and draining lymph nodes correlates with advanced disease grade and stage. Here, we set out to dissect the role of host immune cell-derived IL-30 in PC growth and patient outcome. METHODS: PC-SLCs were implanted in wild type (WT) and IL-30 conditional knockout (IL-30KO) mice. Histopathological and cytofluorimetric analyses of murine tumors and lymphoid tissues prompted analyses of patients' PC samples and follow-ups. RESULTS: Implantation of PC-SLCs in IL-30KO mice, gave rise to slow growing tumors characterized by apoptotic events associated with CD4+T lymphocyte infiltrates and lack of CD4+Foxp3+ T regulatory cells (Tregs). IL-30 knockdown in PC-SLCs reduced cancer cell proliferation, vascularization and intra-tumoral Indoleamine 2,3-Dioxygenase (IDO)+CD11b+Gr-1+ myeloid-derived cells (MDCs) and led to a significant delay in tumor growth and increase in survival. IL-30-silenced tumors developed in IL-30KO mice, IL-30-/-tumors, lacked vascular supply and displayed frequent apoptotic cancer cells entrapped by perforin+TRAIL+CD3+Tlymphocytes, most of which had a CD4+T phenotype, whereas IL-10+TGFß+Foxp3+Tregs were lacking. IL-30 silencing in PC-SLCs prevented lung metastasis in 73% of tumor-bearing WT mice and up to 80% in tumor-bearing IL-30KO mice. In patients with high-grade and locally advanced PC, those with IL-30-/-tumors, showed distinct intra-tumoral cytotoxic granule-associated RNA binding protein (TIA-1)+CD4+Tlymphocyte infiltrate, rare Foxp3+Tregs and a lower biochemical recurrence rate compared to patients with IL-30+/+tumors in which IL-30 is expressed in both tumor cells and infiltrating leukocytes. CONCLUSION: The lack of host leukocyte-derived IL-30 inhibits Tregs expansion, promotes intra-tumoral infiltration of CD4+T lymphocytes and cancer cell apoptosis. Concomitant lack of MDC influx, obtained by IL-30 silencing in PC-SLCs, boosts cytotoxic T lymphocyte activation and cancer cell apoptosis resulting in a synergistic tumor suppression with the prospective benefit of better survival for patients with advanced disease.
Asunto(s)
Interleucinas/genética , Células Madre Neoplásicas/trasplante , Neoplasias de la Próstata/patología , Anciano , Animales , Linfocitos T CD4-Positivos/inmunología , Factores de Transcripción Forkhead/metabolismo , Técnicas de Inactivación de Genes , Humanos , Interleucinas/metabolismo , Activación de Linfocitos , Masculino , Ratones , Persona de Mediana Edad , Clasificación del Tumor , Trasplante de Neoplasias , Células Madre Neoplásicas/inmunología , Estudios Prospectivos , Neoplasias de la Próstata/genética , Neoplasias de la Próstata/inmunología , Transducción de Señal , Linfocitos T Reguladores/inmunología , Microambiente TumoralRESUMEN
During prophase I of meiosis, chromosomes become organized as loop arrays around the proteinaceous chromosome axis. As homologous chromosomes physically pair and recombine, the chromosome axis is integrated into the tripartite synaptonemal complex (SC) as this structure's lateral elements (LEs). While the components of the mammalian chromosome axis/LE-including meiosis-specific cohesin complexes, the axial element proteins SYCP3 and SYCP2, and the HORMA domain proteins HORMAD1 and HORMAD2-are known, the molecular organization of these components within the axis is poorly understood. Here, using expansion microscopy coupled with 2-color stochastic optical reconstruction microscopy (STORM) imaging (ExSTORM), we address these issues in mouse spermatocytes at a resolution of 10 to 20 nm. Our data show that SYCP3 and the SYCP2 C terminus, which are known to form filaments in vitro, form a compact core around which cohesin complexes, HORMADs, and the N terminus of SYCP2 are arrayed. Overall, our study provides a detailed structural view of the meiotic chromosome axis, a key organizational and regulatory component of meiotic chromosomes.
Asunto(s)
Cromosomas de los Mamíferos/química , Cromosomas de los Mamíferos/metabolismo , Microscopía/métodos , Animales , Proteínas de Ciclo Celular/metabolismo , Proteínas de Unión al ADN/metabolismo , Masculino , Mamíferos/genética , Meiosis , Ratones , Espermatocitos/metabolismo , Coloración y Etiquetado , Complejo Sinaptonémico/metabolismoRESUMEN
CD4+ Foxp3+ T regulatory (Treg) cells are key players in preventing lethal autoimmunity. Tregs undertake differentiation processes and acquire diverse functional properties. However, how Treg's differentiation and functional specification are regulated remains incompletely understood. Here, we report that gradient expression of TCF1 and LEF1 distinguishes Tregs into three distinct subpopulations, particularly highlighting a subset of activated Treg (aTreg) cells. Treg-specific ablation of TCF1 and LEF1 renders the mice susceptible to systemic autoimmunity. TCF1 and LEF1 are dispensable for Treg's suppressive capacity but essential for maintaining a normal aTreg pool and promoting Treg's competitive survival. As a consequence, the development of T follicular regulatory (Tfr) cells, which are a subset of aTreg, is abolished in TCF1/LEF1-conditional knockout mice, leading to unrestrained T follicular helper (Tfh) and germinal center B cell responses. Thus, TCF1 and LEF1 act redundantly to control the maintenance and functional specification of Treg subsets to prevent autoimmunity.