Project description:Obesity underpins the development of numerous chronic diseases such as type II diabetes mellitus. It is well established that obesity negatively alters immune cell frequencies and functions. Mucosal Associated Invariant T (MAIT) cells are a population of innate T cells, which we have previously reported are dysregulated in obesity, with altered circulating and adipose tissue frequencies and a reduction in their IFN-gamma production, which is a critical effector function of MAIT cells in host defence. Hence there is increased urgency to characterise the key molecular mechanisms that drive MAIT cell effector functions, and to identify those which are impaired in the obesity setting. In this study, we found that MAIT cells significantly upregulate their rates of glycolysis upon activation in an mTORC1 dependent manner and this is essential for MAIT cell IFN-g production. Furthermore, we show that mTORC1 activation is dependent on amino acid transport via SLC7A5. In obese patients, using RNA sequencing, Seahorse analysis and a series of in vitro experiments, we demonstrate that MAIT cells isolated from obese adults display defective glycolytic metabolism, mTORC1 signalling and SLC7A5 amino acid transport. Collectively our data details the intrinsic metabolic pathways controlling MAIT cell cytokine production and highlights mTORC1 as an important metabolic regulator that is impaired in obesity, leading to altered MAIT cell responses. We report on MAIT cells isolated from lean and obese adults
Project description:To show the similarity among MAIT-iPSCs, hiPSCs and hESCs and the gradual change of global gene expression of reMAIT cells along with differentiation, this experiment was designed. MAIT cells, MAIT-iPSCs, hiPSCs, hESCs, MAIT cells, and reMAIT cells at the several differerent stages of differentiation were collected. Then, they were applied in this experiment.
Project description:Normal adjacent tissues from colorectal cancer patients were collected for MAIT cell sorting. Sorted MAIT cells from seven individual donors were pooled together. Single-cell RNA sequencing libraries were prepared using the Chromium 5' Single Cell Gene Expression Kit (10x Genomics), following the manufacturer's protocol. Sequencing was performed on a NextSeq 500 platform (Illumina).
Project description:A recently identified unconventional T cell population known as mucosal-associated invariant T (MAIT) cells are characterized by the expression of semi-invariant T cell receptor (TCR) with a canonical TRAV1-2/TRAJ33 (Vα7.2/Jα33). These evolutionary conserved, innate-like T cells recognize vitamin B metabolites, derived from some bacteria and fungi. Due to their presence not only in the T cell repertoire of mucosal surfaces but also in peripheral blood and liver, and their significant involvement in a wide range of diseases, in-depth characterization of human MAIT cells is a timely requirement. Studies that examined the transcriptome, immunoproteome, and whole-cell proteome characterized the role of cytotoxic molecules and cytokines in effector functions of MAIT cells and their relationship with some other immune cell subsets. As MAIT cells are classified under the CD3+ T cell compartment and the majority express surface receptor CD8, identifying their proteomic relationship with CD3+ and CD8+ T cells is pivotal. Thus, a high-resolution dataset was generated using the cell populations sorted from peripheral blood mononuclear cells of three healthy volunteers to describe the whole cell proteomes of MAIT, CD3+, and CD8+ T cells. Trypsin-digested peptide samples obtained from the methanol co-precipitation method were analyzed using an Orbitrap FusionTM TribridTM mass spectrometer (Thermo Fisher Scientific, USA) inline coupled to nanoACQUITY ultra-performance liquid chromatography system (Waters, USA) to acquire data-dependent shotgun proteomic data (DDA-MS) for label-free quantification. Analysis of raw DDA-MS data using MaxQuant software and maxLFQ identified and quantified 4,442 protein groups at a 1% false discovery rate. Further analysis identified 3,680 proteins which were detected with a single UniProt accession and a minimum of 2 unique or razor peptides. Thus this proteomic dataset can be used as a reference proteome for future studies on human MAIT cells.
Project description:In this study, we performed single-cell RNA sequencing (scRNA-seq) on MAIT cells extracted from the intestines of young and aged mice. For each age group, MAIT cells from five individual mice were pooled before sequencing.
Project description:MAIT cells (MAITs) represent an abundant T lymphocyte subset with unique specificity for microbial metabolites presented by the MHC-1b molecule, MR1. MAIT conservation along evolution indicates important, non-redundant functions, but their low frequency in mice has hampered their detailed characterization. Here, we performed a transcriptomic analysis of murine MAITs in comparison with NKT subsets and with mainstream T cells in spleen and peripheral organs of B6-MAIT/CAST mice expressing a Rorc-GFP transgene. MAIT and NKT cells have been FACS-sorted after tetramer staining (MR1:5-OP-RU Tet+ for MAIT, CD1d:PBS57Tet+ for NKT), and 1/17 subsetting based on the expression of Rorc.
Project description:Mucosal-associated invariant T (MAIT) cells are innate-like T cells that recognize microbial metabolites through a semi-invariant T cell receptor (TCR). Major questions remain regarding the extent of human MAIT cell functional and clonal diversity. To address these, we analyzed the single-cell transcriptome and TCR repertoire of blood and liver MAIT cells and developed functional RNA sequencing, a method to integrate function and TCR clonotype at single-cell resolution. MAIT cell clonal diversity was comparable to conventional memory T cells, with private TCR repertoires shared across matched tissues. Baseline functional diversity was low and largely related to tissue site. MAIT cells showed stimulus-specific transcriptional responses in vitro, with cells positioned along gradients of activation. Clonal identity influenced resting and activated transcriptional profiles but intriguingly was not associated with the capacity to produce IL- 17. Overall, MAIT cells show phenotypic and functional diversity according to tissue localization, stimulation environment and clonotype.
Project description:Mucosal-associated invariant T (MAIT) cells are innate sensors of viruses, which can augment early immune responses and contribute to protection from lethal infection. Thus, we reasoned MAIT cells may have an adjuvating role in the immunogenicity of replication-incompetent adenovirus vectors, which are novel vaccine platforms for pandemic pathogens such as Ebola virus and SARS-CoV-2. In both mice and human volunteers, immunization with ChAdOx1 (Chimpanzee Adenovirus Ox1) robustly activated MAIT cells. Activation required transduction of plasmacytoid dendritic cells and monocytes to produce IFN- and IL-18, respectively. IFN--induced monocyte-derived TNF was identified as a novel intermediate in this activation pathway, and activation required combinatorial signaling of all three cytokines both in vitro and in vivo. Strikingly, vaccine-induced activation of MAIT cells positively correlated with vaccine-induced T cell responses in human volunteers. Supporting a causal relationship, MAIT cell-deficient mice displayed impaired CD8+ T cell responses to multiple vaccine-encoded antigens. These findings define a novel role for MAIT cells in the immunogenicity of adenovirus vector vaccines, with potential implications for vaccine design.