Project description:MR1T cells are a recently discovered class of T cells that recognize antigens presented by the MHC-I–related molecule MR1 in the absence of microbial infection. The nature of the self-antigens that stimulate MR1T cells remains unclear, hampering our understanding of their physiological role and therapeutic potential. By combining genetic, pharmacological, and biochemical approaches, we found that carbonyl stress and changes in nucleobase metabolism in target cells promote MR1T cell activation. Stimulatory compounds formed by carbonyl adducts of nucleobases were detected within MR1 molecules produced by tumor cells and their abundance and antigenicity were enhanced by drugs that induce carbonyl accumulation. Our data reveal carbonyl nucleobase adducts as MR1T cell antigens. Recognizing cells under carbonyl stress allows MR1T cells to monitor cellular metabolic changes with physiological and therapeutic implications.
Project description:MHC class I-related molecule MR1 presents riboflavin-derived microbial metabolites and folate-derivatives to mucosal-associated invariant T cells, but it is unknown whether MR1 can bind alternative antigens that stimulate other T cell lineages. Here we report that human T cells displaying diverse TCR-α and β chains recognize MR1-expressing cells in the absence of microbial ligands and respond to recombinant MR1 molecules loaded with antigens extracted from stimulatory targets. Transcriptome analysis revealed functional heterogeneity of MR1-reactive T cells (MR1T cells), which displayed differential expression of various transcription factors regulating T cell polarization, proliferation and apoptosis. Accordingly, MR1T cells displayed multiple profiles of chemokine receptor expression and secreted variable combinations of cytokines and growth factors, suggesting a diversity of immunological roles across numerous tissues. Functionally, MR1T cells were capable of inducing dendritic cell maturation and stimulating anti-microbial responses in intestinal epithelial cells. These data demonstrate that MR1 presents endogenous antigens to a novel population of functionally diverse human T cells.
Project description:The purpose of this experiment is to examine the cellular and molecular changes in the microglia and other non-neuron cells in the hippocampus of 7 month old Mr1+/+ and Mr1-/- mice.
Project description:Antisense oligonucleotide (ASO) has the potential to induce hybridization-dependent effects by inadvertent binding of ASOs to RNA with sequences similar to that of the target RNA. In the present study, we examined the effects of the nucleobase derivatives introduced into the gapmer ASOs on gene expression. We performed microarray analysis using NMuLi cells (mouse liver-derived cells) treated with LNA gapmer ASO containing nucleobase modification.
Project description:Mucosal-Associated Invariant T cells (MAIT cells) have a unique specificity for the microbial metabolite 5-OP-RU presented by the non-classical presentation molecule MR1. Upon activation, they release cytotoxic mediators and engage an antimicrobial activity. As a subset of T lymphocytes, MAIT development occurs in the thymus where they acquire their effector phenotype under the control of the key transcription factor ZBTB16. This particular maturation process is in contrast with conventional T cells that egress the thymus with a naive phenotype before populating the secondary lymphoid organs, and the molecular events driving the MAIT lineage decision are poorly known. In the present work, we evaluated the transcriptional events and the role of the slam-SAP pathway on the lineage decision of MR1-restricted T cells by single cell RNAseq. MAIT cells undergoing positive selection were FACS-sorted with a MR1:5-OP-RU labeled tetramer, from thymus of wild-type and sapKO mice. Their transcriptomes were captured using a 10x chromium system.
Project description:The goal of these experiments were to test the on-target and target-adjacent editing efficiencies of different single-nucleobase editing systems. Previous studies have shown that tethering DNA mutating enzymes to Cas9-nickase-UGI complexes results in editing of chromosomal DNA. However, these editing events encompass undesirable target-adjacent nucleobase edits. Here, we characterize a novel approach that reduces the frequency of target-adjacent editing while maintaining a high level of on-target editing.
Project description:Cisplatin, one of the most widely used anticancer drugs, crosslinks DNA and ultimately induces cell death. However, the genomic pattern of cisplatin-DNA adducts remains unknown, due to the lack of a reliable and sensitive genome-wide method. Here we present “cisplatin-seq” to identify genome-wide cisplatin crosslinking sites at base-resolution. Cisplatin-seq reveals that mitochondrial DNA is a preferred target of cisplatin. For nuclear genome, cisplatin-DNA adducts are enriched within promoters and regions harboring transcription termination sites. While the density of GG dinucleotide determines the initial crosslinking of cisplatin, binding of proteins to the genome largely contributes to the accumulative pattern of cisplatin-DNA adducts.