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1.
Front Immunol ; 15: 1341180, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38440736

RESUMO

Mucosal-associated invariant T (MAIT) cells are a unique subset of T cells that recognizes metabolites derived from the vitamin B2 biosynthetic pathway. Since the identification of cognate antigens for MAIT cells, knowledge of the functions of MAIT cells in cancer, autoimmunity, and infectious diseases has been rapidly expanding. Recently, MAIT cells have been found to contribute to visual protection against autoimmunity in the eye. The protective functions of MAIT cells are induced by T-cell receptor (TCR)-mediated activation. However, the underlying mechanisms remain unclear. Thus, this mini-review aims to discuss our findings and the complexity of MAIT cell-mediated immune regulation in the eye.


Assuntos
Oftalmopatias , Células T Invariantes Associadas à Mucosa , Humanos , Autoimunidade , Riboflavina
2.
Cancer Med ; 13(6): e7112, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38509769

RESUMO

BACKGROUND: Patients with non-small cell lung cancer (NSCLC) and chronic obstructive pulmonary disease (COPD) experience worse clinical outcomes but respond better to immunotherapy than patients with NSCLC without COPD. Mucosal-associated invariant T (MAIT) cells, a versatile population of innate immune T lymphocytes, have a crucial function in the response to infection and tumors. This study investigated the distribution of MAIT cells in COPD-associated NSCLC and their involvement in the immune response. METHODS: Flow cytometry, immunohistochemistry, and immunofluorescence were performed on tissue samples of patients with NSCLC, with or without COPD, treated with or without anti-programmed death 1 (PD1) immunotherapy. MAIT cells were stimulated with 5-OP-RU using a mouse subcutaneous tumor model. RESULTS: Tumors contained significantly more MAIT cells than paraneoplastic tissues, and CD8+ MAIT cells accounted for more than 90% of these cells. Patients with NSCLC and COPD had higher CD8+ MAIT cell counts than those with NSCLC without COPD. Additionally, patients with NSCLC and COPD displayed reduced expression of the activation marker, CD69, and functional markers, granzyme B (GZMB) and interferon γ (IFNγ), and higher expression of the immune exhaustion marker, PD1. Among patients who received immunotherapy, the proportion with a complete or partial response was higher in those with COPD than in those without COPD. In patients with NSCLC and COPD, the major pathologic response (MPR) group had higher MAIT levels than those in the no major pathologic response (NPR) group. In the mouse subcutaneous tumor model stimulation of MAIT cells using 5-OP-RU enhanced the antitumor effects of anti-PD1. CONCLUSIONS: In patients with NSCLC and COPD, response to immunotherapy is associated with accumulation of CD8+ MAIT cells showing immune exhaustion. These findings may contribute to innovative approaches for immunotherapy targeting CD8+ MAIT cells.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Células T Invariantes Associadas à Mucosa , Doença Pulmonar Obstrutiva Crônica , Ribitol/análogos & derivados , Uracila/análogos & derivados , Humanos , Carcinoma Pulmonar de Células não Pequenas/metabolismo , Células T Invariantes Associadas à Mucosa/metabolismo , Células T Invariantes Associadas à Mucosa/patologia , Neoplasias Pulmonares/metabolismo , Terapia Neoadjuvante , Biomarcadores/metabolismo , Doença Pulmonar Obstrutiva Crônica/terapia , Imunoterapia
3.
Mol Hum Reprod ; 30(3)2024 Feb 29.
Artigo em Inglês | MEDLINE | ID: mdl-38310328

RESUMO

Preterm birth (PTB) is a major problem affecting perinatal health, directly increasing the mortality risk of mother and infant that often results from the breakdown of the maternal-fetal immune balance. Increasing evidence shows the essential role of mucosal-associated invariant T (MAIT) cells to balance antibacterial function and immune tolerance function during pregnancy. However, the phenotype and function of placental MAIT cells and their specific mechanisms in PTB remain unclear. Here, we report that MAIT cells in placentas from PTBs show increased activation levels and decreased IFN-γ secretion capacity compared with those from normal pregnancies. Moreover, our data indicate gravidity is a factor affecting placental MAIT cells during pregnancies. Multi-omics analysis indicated aberrant immune activation and abnormal increase of lipids and lipid-like metabolites in the PTB placental microenvironment. Moreover, the proportion and activation of MAIT cells were positively correlated with the abnormal increase of lipids and lipid-like metabolites. Together, our work revealed that abnormal activation and impaired function of MAIT cells may be related to abnormal elevation of lipids and lipid-like metabolites in PTB.


Assuntos
Células T Invariantes Associadas à Mucosa , Nascimento Prematuro , Recém-Nascido , Gravidez , Lactente , Humanos , Feminino , Placenta , Feto , Lipídeos
4.
Oncoimmunology ; 13(1): 2312631, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38343750

RESUMO

Mucosal-associated invariant T (MAIT) cells constitute one of the most numerous unconventional T cell subsets, and are characterized by rapid release of Th1- and Th17-associated cytokines and increased cytotoxic functions following activation. MAIT cells accumulate in tumor tissue but show an exhausted phenotype. Here, we investigated if immune checkpoint blockade (ICB) with antibodies to PD-1 or PD-L1 affects the function of circulating MAIT cells from non-small cell lung cancer patients. ICB increased the proliferation and co-expression of the activation markers HLA-DR and CD38 on MAIT cells in most patients after the first treatment cycle, irrespective of treatment outcome. Furthermore, production of cytokines, especially TNF and IL-2, also increased after treatment, as did MAIT cell polyfunctionality. These results indicate that MAIT cells respond to ICB, and that MAIT cell reinvigoration may contribute to tumor regression in patients undergoing immune checkpoint therapy.


Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , Células T Invariantes Associadas à Mucosa , Humanos , Células T Invariantes Associadas à Mucosa/metabolismo , Carcinoma Pulmonar de Células não Pequenas/tratamento farmacológico , Inibidores de Checkpoint Imunológico , Neoplasias Pulmonares/tratamento farmacológico , Citocinas/metabolismo
5.
JCI Insight ; 9(5)2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38300704

RESUMO

Adoptive transfer of immunoregulatory cells can prevent or ameliorate graft-versus-host disease (GVHD), which remains the main cause of nonrelapse mortality after allogeneic hematopoietic stem cell transplantation. Mucosal-associated invariant T (MAIT) cells were recently associated with tissue repair capacities and with lower rates of GVHD in humans. Here, we analyzed the immunosuppressive effect of MAIT cells in an in vitro model of alloreactivity and explored their adoptive transfer in a preclinical xenogeneic GVHD model. We found that MAIT cells, whether freshly purified or short-term expanded, dose-dependently inhibited proliferation and activation of alloreactive T cells. In immunodeficient mice injected with human PBMCs, MAIT cells greatly delayed GVHD onset and decreased severity when transferred early after PBMC injection but could also control ongoing GVHD when transferred at delayed time points. This effect was associated with decreased proliferation and effector function of human T cells infiltrating tissues of diseased mice and was correlated with lower circulating IFN-γ and TNF-α levels and increased IL-10 levels. MAIT cells acted partly in a contact-dependent manner, which likely required direct interaction of their T cell receptor with MHC class I-related molecule (MR1) induced on host-reactive T cells. These results support the setup of clinical trials using MAIT cells as universal therapeutic tools to control severe GVHD or mucosal inflammatory disorders.


Assuntos
Doença Enxerto-Hospedeiro , Transplante de Células-Tronco Hematopoéticas , Células T Invariantes Associadas à Mucosa , Humanos , Camundongos , Animais , Leucócitos Mononucleares , Doença Enxerto-Hospedeiro/prevenção & controle , Doença Enxerto-Hospedeiro/etiologia , Transplante de Células-Tronco Hematopoéticas/efeitos adversos , Receptores de Antígenos de Linfócitos T
6.
Int Immunopharmacol ; 130: 111699, 2024 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-38377855

RESUMO

Intracranial infections are among the most common complications of neurosurgery, with their incidence remaining high despite advancements in current neurosurgical techniques and aseptic technology. While the role of mucosal-associated invariant T (MAIT) cells, a subset of innate-like T lymphocytes, in bacterial defense is well-established, their involvement in intracranial infections remains unclear. In this study, we utilized flow cytometry to assess the phenotype and function of circulating and CSF MAIT cells. Our findings revealed that MAIT cells were higher in the CSF compared to blood. Notably, a higher percentage of IL-17A + MAIT cells was detected in the CSF of patients with intracranial infections. Moreover, markers indicating activation and exhaustion were significantly upregulated in CSF MAIT cells. Furthermore, elevated levels of pro-inflammatory cytokines, including IL-1ß, IL-12, and IL-18, were detected in the CSF supernatants. We hypothesized that the elevated levels of IL-1ß, IL-12, and IL-18 in the inflammatory milieu synergistically activate MAIT cells in the CSF. In particular, CD25 and Tim-3 expression of MAIT cells was increased by stimulation with IL-1ß, IL-12, and IL-18 or CSF supernatants of intracranial infection patients. Collectively, these findings provide important information underlying the innate immune response of patients with intracranial infections.


Assuntos
Células T Invariantes Associadas à Mucosa , Humanos , Interleucina-18/metabolismo , Citocinas/metabolismo , Interleucina-12/metabolismo , Craniotomia
7.
Virus Res ; 341: 199315, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38211733

RESUMO

Prolonged T cell lymphopenia is common in COVID-19, caused by SARS-CoV-2. While the mechanisms of lymphopenia during COVID-19 remain elusive, it is especially pronounced in a specialized innate-like T cell population called Mucosal Associated Invariant T cells (MAITs). MAITs has been suggested to express Angiotensin-Converting Enzyme 2 (ACE2), which is the well-known cellular receptor for SARS-CoV-2. However, it is still unclear if SARS-CoV-2 can infect or affect MAIT cells directly. In this study, we performed multicolor flow cytometry on peripheral blood mononuclear cells obtained from COVID-19 patients to assess the frequencies of CD8+Vα7.2+CD161+ MAIT subsets at acute and convalescent disease phases. The susceptibility of MAITs and T cells to direct exposure by SARS-CoV-2 was analysed using cells isolated from healthy donor buffy coats by viability assays, virus-specific RT-PCR, and flow cytometry. In situ lung immunofluorescence was used to evaluate retention of T cells, especially MAIT cells, in lung tissues during acute COVID-19. Our study confirms previous reports indicating that circulating MAITs are activated, and their frequency is declined in patients with acute SARS-CoV-2 infection, whereas an accumulation of MAITs and T cells was seen in the lung tissue of individuals with fatal COVID-19. However, despite a fraction of MAITs found to express ACE2, no evidence for the susceptibility of MAITs for direct infection or activation by SARS-CoV-2 particles was observed. Thus, their activation and decline in the circulation is most likely explained by indirect mechanisms involving other immune cells and cytokine-induced pro-inflammatory environment but not by direct exposure to viral particles at the infection site.


Assuntos
COVID-19 , Linfopenia , Células T Invariantes Associadas à Mucosa , Humanos , Enzima de Conversão de Angiotensina 2 , Leucócitos Mononucleares , SARS-CoV-2 , Pulmão
8.
J Immunol ; 212(6): 933-940, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38275935

RESUMO

In response to microbial infection, the nonclassical Ag-presenting molecule MHC class I-related protein 1 (MR1) presents secondary microbial metabolites to mucosal-associated invariant T (MAIT) cells. In this study, we further characterize the repertoire of ligands captured by MR1 produced in Hi5 (Trichoplusia ni) cells from Mycobacterium smegmatis via mass spectrometry. We describe the (to our knowledge) novel MR1 ligand photolumazine (PL)V, a hydroxyindolyl-ribityllumazine with four isomers differing in the positioning of a hydroxyl group. We show that all four isomers are produced by M. smegmatis in culture and that at least three can induce MR1 surface translocation. Furthermore, human MAIT cell clones expressing distinct TCR ß-chains differentially responded to the PLV isomers, demonstrating that the subtle positioning of a single hydroxyl group modulates TCR recognition. This study emphasizes structural microheterogeneity within the MR1 Ag repertoire and the remarkable selectivity of MAIT cell TCRs.


Assuntos
Células T Invariantes Associadas à Mucosa , Humanos , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Antígenos de Histocompatibilidade Menor , Antígenos de Histocompatibilidade Classe I/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo
9.
Sci Immunol ; 9(91): eade6924, 2024 Jan 26.
Artigo em Inglês | MEDLINE | ID: mdl-38277465

RESUMO

Mucosal-associated invariant T (MAIT) cells are innate-like T cells that recognize bacterial riboflavin-based metabolites as activating antigens. Although MAIT cells are found in tissues, it is unknown whether any host tissue-derived antigens exist. Here, we report that a sulfated bile acid, cholic acid 7-sulfate (CA7S), binds the nonclassical MHC class I protein MR1 and is recognized by MAIT cells. CA7S is a host-derived metabolite whose levels were reduced by more than 98% in germ-free mice. Deletion of the sulfotransferase 2a family of enzymes (Sult2a1-8) responsible for CA7S synthesis reduced the number of thymic MAIT cells in mice. Moreover, recognition of CA7S induced MAIT cell survival and the expression of a homeostatic gene signature. By contrast, recognition of a previously described foreign antigen, 5-(2-oxopropylideneamino)-6-d-ribitylaminouracil (5-OP-RU), drove MAIT cell proliferation and the expression of inflammatory genes. Thus, CA7S is an endogenous antigen for MAIT cells, which promotes their development and function.


Assuntos
Células T Invariantes Associadas à Mucosa , Animais , Camundongos , Ácidos e Sais Biliares , Ligantes , Sulfatos , Antígenos de Histocompatibilidade Menor/metabolismo , Antígenos
10.
Allergol Int ; 73(1): 94-106, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37336695

RESUMO

BACKGROUND: Mepolizumab treatment improves symptom control and quality of life and reduces exacerbations in patients with severe eosinophilic asthma. However, biomarkers that predict therapeutic effectiveness must be determined for use in precision medicine. Herein, we elucidated the dynamics of various parameters before and after treatment as well as patient characteristics predictive of clinical responsiveness to mepolizumab after 1-year treatment. METHODS: Twenty-seven patients with severe asthma were treated with mepolizumab for one year. Asthma control test scores, pulmonary function tests, fractional exhaled nitric oxide levels, and blood samples were evaluated. Additionally, we explored the role of CD69-positive mucosal-associated invariant T (MAIT) cells as a candidate biomarker for predicting treatment effectiveness by evaluating an OVA-induced asthma murine model using MR1 knockout mice, where MAIT cells were absent. RESULTS: The frequencies of CD69-positive group 1 innate lymphoid cells, group 3 innate lymphoid cells, natural killer cells, and MAIT cells decreased after mepolizumab treatment. The frequency of CD69-positive MAIT cells and neutrophils was lower and serum periostin levels were higher in responders than in non-responders. In the OVA-induced asthma murine model, CD69-positive MAIT cell count in the whole mouse lung was significantly higher than that in the control mice. Moreover, OVA-induced eosinophilic airway inflammation was exacerbated in the MAIT cell-deficient MR1 knockout mice. CONCLUSIONS: This study shows that circulating CD69-positive MAIT cells, neutrophils, and serum periostin might predict the real-world response after 1-year mepolizumab treatment. Furthermore, MAIT cells potentially have a protective role against type 2 airway inflammation.


Assuntos
Asma , Células T Invariantes Associadas à Mucosa , Humanos , Animais , Camundongos , Neutrófilos , Imunidade Inata , Modelos Animais de Doenças , Ovalbumina/uso terapêutico , Qualidade de Vida , Linfócitos , Inflamação , Biomarcadores , Camundongos Knockout
11.
Nat Rev Immunol ; 24(3): 178-192, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37773272

RESUMO

MHC antigen presentation plays a fundamental role in adaptive and semi-invariant T cell immunity. Distinct MHC molecules bind antigens that differ in chemical structure, origin and location and present them to specialized T cells. MHC class I-related protein 1 (MR1) presents a range of small molecule antigens to MR1-restricted T (MR1T) lymphocytes. The best studied MR1 ligands are derived from microbial metabolism and are recognized by a major class of MR1T cells known as mucosal-associated invariant T (MAIT) cells. Here, we describe the MR1 antigen presentation pathway: the known types of antigens presented by MR1, the location where MR1-antigen complexes form, the route followed by the complexes to the cell surface, the mechanisms involved in termination of MR1 antigen presentation and the accessory cellular proteins that comprise the MR1 antigen presentation machinery. The current road map of the MR1 antigen presentation pathway reveals potential strategies for therapeutic manipulation of MR1T cell function and provides a foundation for further studies that will lead to a deeper understanding of MR1-mediated immunity.


Assuntos
Apresentação de Antígeno , Células T Invariantes Associadas à Mucosa , Humanos , Antígenos de Histocompatibilidade Menor , Antígenos de Histocompatibilidade Classe I , Antígenos
12.
Allergol Int ; 73(1): 40-47, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37567833

RESUMO

Despite recent advances in asthma treatments, the search for novel therapies remains necessary because there are still patients with recurrent asthma exacerbations and poor responses to the existing treatments. Since group 2 innate lymphoid cells (ILC2) play a pivotal role in asthma by triggering and exacerbating type 2 inflammation, controlling ILC2s function is key to combating severe asthma. Mucosal-associated invariant T (MAIT) cells are innate-like T cells abundant in humans and are activated both in a T cell receptor-dependent and -independent manner. MAIT cells are composed of MAIT1 and MAIT17 based on the expression of transcription factors T-bet and RORγt, respectively. MAIT cells play pivotal roles in host defense against pathogens and in tissue repair and are essential for the maintenance of immunity and hemostasis. Our recent studies revealed that MAIT cells inhibit both ILC2 proliferation and functions in a mouse model of airway inflammation. MAIT cells may alleviate airway inflammation in two ways, by promoting airway epithelial cell barrier repair and by repressing ILC2s. Therefore, reagents that promote MAIT cell-mediated suppression of ILC2 proliferation and function, or designer MAIT cells (genetically engineered to suppress ILC2s or promote repair of airway damage), may be effective therapeutic agents for severe asthma.


Assuntos
Asma , Células T Invariantes Associadas à Mucosa , Camundongos , Animais , Humanos , Imunidade Inata , Linfócitos , Inflamação
13.
J Exp Med ; 221(2)2024 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-38117256

RESUMO

Mucosal-associated invariant T (MAIT) cells harbor evolutionarily conserved TCRs, suggesting important functions. As human and mouse MAIT functional programs appear distinct, the evolutionarily conserved MAIT functional features remain unidentified. Using species-specific tetramers coupled to single-cell RNA sequencing, we characterized MAIT cell development in six species spanning 110 million years of evolution. Cross-species analyses revealed conserved transcriptional events underlying MAIT cell maturation, marked by ZBTB16 induction in all species. MAIT cells in human, sheep, cattle, and opossum acquired a shared type-1/17 transcriptional program, reflecting ancestral features. This program was also acquired by human iNKT cells, indicating common differentiation for innate-like T cells. Distinct type-1 and type-17 MAIT subsets developed in rodents, including pet mice and genetically diverse mouse strains. However, MAIT cells further matured in mouse intestines to acquire a remarkably conserved program characterized by concomitant expression of type-1, type-17, cytotoxicity, and tissue-repair genes. Altogether, the study provides a unifying view of the transcriptional features of innate-like T cells across evolution.


Assuntos
Células T Invariantes Associadas à Mucosa , Humanos , Bovinos , Animais , Camundongos , Ovinos , Diferenciação Celular , Membrana Celular , Especificidade da Espécie , Mamíferos/genética
14.
J Immunol ; 212(3): 389-396, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-38117799

RESUMO

Mucosal-associated invariant T (MAIT) cells are an abundant population of unconventional T cells in humans and play important roles in immune defense against microbial infections. Severe COVID-19 is associated with strong activation of MAIT cells and loss of these cells from circulation. In the present study, we investigated the capacity of MAIT cells to recover after severe COVID-19. In longitudinal paired analysis, MAIT cells initially rebounded numerically and phenotypically in most patients at 4 mo postrelease from the hospital. However, the rebounding MAIT cells displayed signs of persistent activation with elevated expression of CD69, CD38, and HLA-DR. Although MAIT cell function was restored in many patients, a subgroup displayed a predominantly PD-1high functionally impaired MAIT cell pool. This profile was associated with poor expression of IFN-γ and granzyme B in response to IL-12 + L-18 and low levels of polyfunctionality. Unexpectedly, although the overall T cell counts recovered, normalization of the MAIT cell pool failed at 9-mo follow-up, with a clear decline in MAIT cell numbers and a further increase in PD-1 levels. Together, these results indicate an initial transient period of inconsistent recovery of MAIT cells that is not sustained and eventually fails. Persisting MAIT cell impairment in previously hospitalized patients with COVID-19 may have consequences for antimicrobial immunity and inflammation and could potentially contribute to post-COVID-19 health problems.


Assuntos
COVID-19 , Células T Invariantes Associadas à Mucosa , Humanos , Antígenos HLA-DR , Inflamação
15.
Brain Behav Immun ; 116: 321-328, 2024 02.
Artigo em Inglês | MEDLINE | ID: mdl-38157945

RESUMO

Mucosal-associated invariant T (MAIT) cells are a subpopulation of innate-like T cells that can be found throughout the body, predominantly in mucosal sites, the lungs and in the peripheral blood. MAIT cells recognize microbial-derived vitamin B (e.g., riboflavin) metabolite antigens that are presented by the major histocompatibility complex class I-like protein, MR1, found on a variety of cell types in the periphery and the CNS. Since their original discovery, MAIT cells have been studied predominantly in their roles in diseases in the periphery; however, it was not until the early 2000s that these cells were first examined for their contributions to disorders of the CNS, with the bulk of the work being done within the past few years. Currently, the MR1/MAIT cell axis has been investigated in only a few neurological diseases including, multiple sclerosis and experimental autoimmune encephalomyelitis, brain cancer/tumors, ischemia, cerebral palsy, general aging and, most recently, Alzheimer's disease. Each of these diseases demonstrates a role for this under-studied innate immune axis in its neuropathology. Together, they highlight the importance of studying the MR1/MAIT cell axis in CNS disorders. Here, we review the contributions of the MR1/MAIT cell axis in the progression or remission of these neurological diseases. This work has shed some light in terms of potentially exploiting the MR1/MAIT cell axis in novel therapeutic applications.


Assuntos
Doenças do Sistema Nervoso Central , Células T Invariantes Associadas à Mucosa , Humanos , Antígenos de Histocompatibilidade Menor/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo , Riboflavina/metabolismo , Doenças do Sistema Nervoso Central/metabolismo
16.
Inflamm Res ; 73(1): 35-46, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38147125

RESUMO

OBJECTIVE: Here, we explored the phenotype and function of MAIT cells in the peripheral blood of patients with HSP. METHODS: Blood samples from HSP patients and HDs were assessed by flow cytometry and single-cell RNA sequencing to analyze the proportion, phenotype, and function of MAIT cells. Th-cytokines in the serum of HSP patients were analyzed by CBA. IgA in cocultured supernatant was detected by CBA to analyze antibody production by B cells. RESULTS: The percentage of MAIT cells in HSP patients was significantly reduced compared with that in HDs. Genes related to T cell activation and effector were up-regulated in HSP MAIT cells, indicating a more activated phenotype. In addition, HSP MAIT cells displayed a Th2-like profile with the capacity to produce more IL-4 and IL-5, and IL-4 was correlated with IgA levels in the serum of HSP patients. Furthermore, CD40L was up-regulated in HSP MAIT cells, and CD40L+ MAIT cells showed an increased ability to produce IL-4 and to enhance IgA production by B cells. CONCLUSION: Our data demonstrate that MAIT cells in HSP patients exhibit an activated phenotype. The enhanced IL-4 production and CD40L expression of MAIT cells in HSP patients could take part in the pathogenesis of HSP.


Assuntos
Vasculite por IgA , Células T Invariantes Associadas à Mucosa , Humanos , Formação de Anticorpos , Ligante de CD40 , Imunoglobulina A , Interleucina-4
17.
Nan Fang Yi Ke Da Xue Xue Bao ; 43(11): 1881-1885, 2023 Nov 20.
Artigo em Chinês | MEDLINE | ID: mdl-38081605

RESUMO

OBJECTIVE: To investigate the role of mucosal-associated invariant T (MAIT) cells in the regulatory mechanism of adipose browning. METHODS: A mouse model with functional deficiency of MAIT cells was established for comparison with the wild-type mice for levels of brown adipose tissue markers in response to cold stimulation using Western blotting and RT-PCR. Flow cytometry was used to analyze the changes in the number, activation level and cytokine secretion ability of MAIT cells in mouse adipose tissue after cold stimulation. In a co-culture system of MAIT cells and adipocytes, the effect of interleukin-4 (IL-4) blocking antibodies on the expressions of brown adipose tissue markers in the adipocytes was evaluated using Western blotting and RT-PCR. In a mouse model of MAIT cell deficiency, the changes in adipose browning-related indicators in response to cold stimulation were analyzed using metabolic cages, immunohistochemistry, Western blotting and the Seahorse method. RESULTS: In both the mouse models of functional deficiency of MAIT cells and wild-type mice, cold stimulation significantly increased the expression levels of brown adipose tissue markers UCP-1 and PGC1-α and upregulated CD69 and IL-4 expressions in the adipose tissue without significantly affecting the number of MAIT cells in the adipose tissue. In the coculture experiment, the adipocytes showed obviously increased browning level after co-culture with MAIT cells (P < 0.05), but blocking IL-4 signaling strongly downregulated the browning level (P < 0.05). The MAIT cell-deficient mice showed obviously lower levels of energy expenditure, adipose browning and metabolism of the adipocytes compared with the wild-type mice in response to cold stimulation (P < 0.05). CONCLUSION: MAIT cells participate in adipose browning in mice, and cold stimulation promotes MAIT cell secretion of IL-4 to positively regulate adipose browning.


Assuntos
Células T Invariantes Associadas à Mucosa , Animais , Camundongos , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Interleucina-4/metabolismo , Obesidade/metabolismo
18.
PLoS One ; 18(11): e0285918, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37922286

RESUMO

OBJECTIVES: Mucosal-Associated Invariant T (MAIT) cells are T cells with a semi-invariant T cell receptor (TCR), recognizing riboflavin precursors presented by a non-polymorphic MR1 molecule. As these precursors are produced by the gut microbiome, we characterized the frequency, phenotype and clonality of MAIT cells in human colons with and without Crohn's disease (CD). METHODS: The transcriptome of MAIT cells sorted from blood and intestinal lamina propria cells from colectomy recipients were compared with other CD8+ T cells. Colon biopsies from an additional ten CD patients and ten healthy controls (HC) were analyzed by flow cytometry. TCR genes were sequenced from individual MAIT cells from these biopsies and compared with those of MAIT cells from autologous blood. RESULTS: MAIT cells in the blood and colon showed a transcriptome distinct from other CD8 T cells, with more expression of the IL-23 receptor. MAIT cells were enriched in the colons of CD patients, with less NKG2D in inflamed versus uninflamed segments. Regardless of disease, most MAIT cells expressed integrin α4ß7 in the colon but not in the blood, where they were enriched for α4ß7 expression. TCR sequencing revealed heterogeneity in the colon and blood, with few public sequences associated with cohorts. CONCLUSION: MAIT cells are enriched in the colons of CD patients and disproportionately express molecules (IL-23R, integrin α4ß7) targeted by CD therapeutics, to suggest a pathogenic role for them in CD. Public TCR sequences were neither common nor sufficiently restricted to a cohort to suggest protective or pathogenic antigen-specificities.


Assuntos
Doença de Crohn , Células T Invariantes Associadas à Mucosa , Humanos , Receptores de Antígenos de Linfócitos T alfa-beta/genética , Receptores de Antígenos de Linfócitos T alfa-beta/metabolismo , Doença de Crohn/genética , Doença de Crohn/metabolismo , Antígenos de Histocompatibilidade Classe I/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Colo/metabolismo
19.
Nat Commun ; 14(1): 7372, 2023 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-37968302

RESUMO

Mucosal-associated invariant T (MAIT) cells have been implicated in various inflammatory diseases of barrier organs, but so far, their role in kidney disease is unclear. Here we report that MAIT cells that recognize their prototypical ligand, the vitamin B2 intermediate 5-OP-RU presented by MR1, reside in human and mouse kidneys. Single cell RNAseq analysis reveals several intrarenal MAIT subsets, and one, carrying the genetic fingerprint of tissue-resident MAIT17 cells, is activated and expanded in a murine model of crescentic glomerulonephritis (cGN). An equivalent subset is also present in kidney biopsies of patients with anti-neutrophil cytoplasmatic antibody (ANCA)-associated cGN. MAIT cell-deficient MR1 mice show aggravated disease, whereas B6-MAITCAST mice, harboring higher MAIT cell numbers, are protected from cGN. The expanded MAIT17 cells express anti-inflammatory mediators known to suppress cGN, such as CTLA-4, PD-1, and TGF-ß. Interactome analysis predicts CXCR6 - CXCL16-mediated cross-talk with renal mononuclear phagocytes, known to drive cGN progression. In line, we find that cGN is aggravated upon CXCL16 blockade. Finally, we present an optimized 5-OP-RU synthesis method which we apply to attenuating cGN in mice. In summary, we propose that CXCR6+ MAIT cells might play a protective role in cGN, implicating them as a potential target for anti-inflammatory therapies.


Assuntos
Nefropatias , Células T Invariantes Associadas à Mucosa , Humanos , Animais , Camundongos , Células Mieloides/metabolismo , Nefropatias/metabolismo , Anti-Inflamatórios/metabolismo , Antígenos de Histocompatibilidade Classe I/metabolismo
20.
Sci Immunol ; 8(89): eabn8531, 2023 11 10.
Artigo em Inglês | MEDLINE | ID: mdl-37948512

RESUMO

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.


Assuntos
Células T Invariantes Associadas à Mucosa , Humanos , Transcriptoma , Linfócitos T CD8-Positivos , Timo , Lipídeos
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