Unveiling the heterogeneity of NKT cells in the liver through single cell RNA sequencing
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ABSTRACT: CD1d-dependent type I NKT cells, which are activated by lipid antigen, are known to play important roles in innate and adaptive immunity, as are a portion of type II NKT cells. However, the heterogeneity of NKT cells, especially NKT-like cells, remains largely unknown. Here, we report the profiling of NKT (NK1.1+CD3e+) cells in livers from wild type (WT), Jα18-deficient and CD1d- deficient mice by single-cell RNA sequencing. Unbiased transcriptional clustering revealed distinct cell subsets. The transcriptomic profiles identified the well-known CD1d-dependent NKT cells and defined two CD1d-independent NKT cell subsets. In addition, validation of marker genes revealed the differential organ distribution and landscape of NKT cell subsets during liver tumor progression. More importantly, we found that CD1d-independent Sca-1−CD62L+ NKT cells showed a strong ability to secrete IFN-γ after costimulation with IL-2, IL-12 and IL-18 in vitro. Collectively, our findings provide a comprehensive characterization of NKT cell heterogeneity and unveil a previously undefined functional NKT cell subset.
Project description:Invariant NKT (iNKT) cells comprise a heterogeneous group of terminally differentiated, non-circulating, tissue-resident T-lymphocytes that recognize glycolipids, including alpha-galactosylceramide (aGalCer), in the context of CD1d. Here, we show that murine and human liver-resident aGalCer/CD1d-binding iNKTs correspond to a novel Zbtb16+/Tbx21+/Gata3+/Maflow/Rorc– subset that exhibits profound plasticity. Repetitive encounters of these cells with intravenously-delivered aGalCer/CD1d-coated nanoparticles (NPs) trigger their differentiation into immunoregulatory, IL-10/IL-21-producing, Mafhigh cells expressing a T-regulatory type 1 (TR1)-like transcriptional signature.
Project description:T cell development is a complicatedly hierarchical process which is closely related with the chromatin activation and gene transcription. CD4+CD8+ double-positive (DP) thymocytes give rise to both conventional TCRαβ+ T cells and natural killer T cells, but they display different characteristics. Compared with conventional TCRαβ+ T cells, invariant natural killer T cells (iNKT cells) as the major population of NKT cells, are CD1d-restricted, recognize glycolipid antigens and rapidly exert effector functions after stimulation. However, the specific molecular mechanism of early iNKT cell development remain incompletely understood. Here the authors show that deletion of Chromatin assembly factor 1B (CHAF1b) remains the normal development of conventional TCRαβ+ T cell, but specifically impacts iNKT cell generation and completely impairs iNKT cell development from stage 0 with a PLZF independent way. This dysregulation is accompanied by a specific decrease in gene transcription of Vα14-Jα18, an impairment in TCR signaling and PLZF expression. Notably, ectopic expression of a transgenic Vα14-Jα18 TCR completely rescues these defects in Chaf1b-deficient iNKT cells. Moreover, cytokine secretion and anti-tumor activity are substantially maintained in Chaf1b-deficient iNKT cells with transgenic Vα14-Jα18 TCR. Our study identifies CHAF1b as a distinct regulator controls early development of iNKT cells via transcriptional regulation of Vα14-Jα18.
Project description:T cell development is a complicatedly hierarchical process which is closely related with the chromatin activation and gene transcription. CD4+CD8+ double-positive (DP) thymocytes give rise to both conventional TCRαβ+ T cells and natural killer T cells, but they display different characteristics. Compared with conventional TCRαβ+ T cells, invariant natural killer T cells (iNKT cells) as the major population of NKT cells, are CD1d-restricted, recognize glycolipid antigens and rapidly exert effector functions after stimulation. However, the specific molecular mechanism of early iNKT cell development remain incompletely understood. Here the authors show that deletion of Chromatin assembly factor 1B (CHAF1b) remains the normal development of conventional TCRαβ+ T cell, but specifically impacts iNKT cell generation and completely impairs iNKT cell development from stage 0 with a PLZF independent way. This dysregulation is accompanied by a specific decrease in gene transcription of Vα14-Jα18, an impairment in TCR signaling and PLZF expression. Notably, ectopic expression of a transgenic Vα14-Jα18 TCR completely rescues these defects in Chaf1b-deficient iNKT cells. Moreover, cytokine secretion and anti-tumor activity are substantially maintained in Chaf1b-deficient iNKT cells with transgenic Vα14-Jα18 TCR. Our study identifies CHAF1b as a distinct regulator controls early development of iNKT cells via transcriptional regulation of Vα14-Jα18.
Project description:Solar UV represents a ubiquitous environmental physical insult. Thus, to maintain its integrity as an effective barrier, skin must be unusually resistant to cell death. However, UV overexposure causes sunburn1,2 (necrosis and inflammation) and cells that survive harbour damaged DNA, which if not repaired or removed by apoptosis can lead to skin cancer development3-10. CD1d, a transmembrane protein identified in glycolipid antigen presentation11,12 to invariant natural killer T (NKT) cells13,14 is expressed by epithelial cells of most tissues including skin15-17, and shares close homology between humans and mice12. Since CD1d and NKT cells are implicated in regulating UV skin carcinogenesis4,18, we studied susceptibility to UV-induced sunburn in mice either lacking expression of both CD1d and NKT cells or expressing CD1d without NKT cells. Here we show that CD1d, but not NKT cells is necessary for UV to cause sunburn. CD1d causes cells to resist apoptosis in response to UV overexposure as the means to promote cell survival and directs the expression of inflammatory response genes, resulting in tissue destruction and skin inflammation. This previously unknown action of CD1d links the etiology of sunburn to skin cancer. Keywords = CD1d knockout, UV, sunburn, cancer Keywords: other
Project description:Intestinal homeostasis is maintained through the combined functions of epithelial and immune cells that collaborate to preserve the integrity of the intestinal barrier. However, the mechanisms by which immune cell populations regulate intestinal epithelial cell (IEC) homeostasis remain unclear. Here, we use a multi-omics approach to study the immune-epithelial crosstalk and identify CD1d-restricted Natural Killer T (NKT) cells as regulators of IEC biology. We find that NKT cells are abundant in the proximal small intestine and show hallmarks of activation at steady state. Subsequently, NKT cells regulate the survival and the transcriptional and cellular composition landscapes of IECs in intestinal organoids, through mechanisms dependent on IFN-γ and IL-4 secretion by NKT cells but independent of the expression of CD1d on IECs. In vivo, lack of NKT cells results in an increase in IEC turnover, while NKT cell activation leads to IFN-γ-dependent epithelial apoptosis. Our findings propose NKT cells as potent producers of cytokines that contribute to the regulation of IEC homeostasis.
Project description:Intestinal homeostasis is maintained through the combined functions of epithelial and immune cells that collaborate to preserve the integrity of the intestinal barrier. However, the mechanisms by which immune cell populations regulate intestinal epithelial cell (IEC) homeostasis remain unclear. Here, we use a multi-omics approach to study the immune-epithelial crosstalk and identify CD1d-restricted Natural Killer T (NKT) cells as regulators of IEC biology. We find that NKT cells are abundant in the proximal small intestine and show hallmarks of activation at steady state. Subsequently, NKT cells regulate the survival and the transcriptional and cellular composition landscapes of IECs in intestinal organoids, through mechanisms dependent on IFN-γ and IL-4 secretion by NKT cells but independent of the expression of CD1d on IECs. In vivo, lack of NKT cells results in an increase in IEC turnover, while NKT cell activation leads to IFN-γ-dependent epithelial apoptosis. Our findings propose NKT cells as potent producers of cytokines that contribute to the regulation of IEC homeostasis.
Project description:Intestinal homeostasis is maintained through the combined functions of epithelial and immune cells that collaborate to preserve the integrity of the intestinal barrier. However, the mechanisms by which immune cell populations regulate intestinal epithelial cell (IEC) homeostasis remain unclear. Here, we use a multi-omics approach to study the immune-epithelial crosstalk and identify CD1d-restricted Natural Killer T (NKT) cells as regulators of IEC biology. We find that NKT cells are abundant in the proximal small intestine and show hallmarks of activation at steady state. Subsequently, NKT cells regulate the survival and the transcriptional and cellular composition landscapes of IECs in intestinal organoids, through mechanisms dependent on IFN-γ and IL-4 secretion by NKT cells but independent of the expression of CD1d on IECs. In vivo, lack of NKT cells results in an increase in IEC turnover, while NKT cell activation leads to IFN-γ-dependent epithelial apoptosis. Our findings propose NKT cells as potent producers of cytokines that contribute to the regulation of IEC homeostasis.
Project description:Intestinal homeostasis is maintained through the combined functions of epithelial and immune cells that collaborate to preserve the integrity of the intestinal barrier. However, the mechanisms by which immune cell populations regulate intestinal epithelial cell (IEC) homeostasis remain unclear. Here, we use a multi-omics approach to study the immune-epithelial crosstalk and identify CD1d-restricted Natural Killer T (NKT) cells as regulators of IEC biology. We find that NKT cells are abundant in the proximal small intestine and show hallmarks of activation at steady state. Subsequently, NKT cells regulate the survival and the transcriptional and cellular composition landscapes of IECs in intestinal organoids, through mechanisms dependent on IFN-γ and IL-4 secretion by NKT cells but independent of the expression of CD1d on IECs. In vivo, lack of NKT cells results in an increase in IEC turnover, while NKT cell activation leads to IFN-γ-dependent epithelial apoptosis. Our findings propose NKT cells as potent producers of cytokines that contribute to the regulation of IEC homeostasis.
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:T cells play a critical role in liver immunity and take part both in the initiation and in the resolution of intrahepatic inflammation. The liver contains conventional CD4 T cells, and Natural Killer T (NKT) cells that express an invariant Vα14 T cell receptor that recognizes glycolipid/CD1d antigen complexes (iNKTs) and play a role in immune surveillance and immune homeostasis. ImmPRes includes a TMT based dataset characterising the proteomes of ex-vivo liver derived CD4+ T cells along with invariant NKT (iNKT) cells