Project description:Lipid overload and adipocyte dysfunction are key to the development of insulin resistance and can be induced by a high-fat diet. CD1d-restricted invariant natural killer T (iNKT) cells have been proposed as mediators between lipid overload and insulin resistance, but recent studies found decreased iNKT cell numbers and marginal effects of iNKT cell depletion on insulin resistance under high-fat diet conditions. Here, we focused on the role of iNKT cells under normal conditions. We showed that iNKT cell–deficient mice on a low-fat diet, considered a normal diet for mice, displayed a distinctive insulin resistance phenotype without overt adipose tissue inflammation. Insulin resistance was characterized by adipocyte dysfunction, including adipocyte hypertrophy, increased leptin, and decreased adiponectin levels. The lack of liver abnormalities in CD1d-null mice together with the enrichment of CD1d-restricted iNKT cells in both mouse and human adipose tissue indicated a specific role for adipose tissue–resident iNKT cells in the development of insulin resistance. Strikingly, iNKT cell function was directly modulated by adipocytes, which acted as lipid antigen-presenting cells in a CD1d-mediated fashion. Based on these findings, we propose that, especially under low-fat diet conditions, adipose tissue–resident iNKT cells maintain healthy adipose tissue through direct interplay with adipocytes and prevent insulin resistance. four samples
Project description:Invariant natural killer T-lymphocytes (iNKT) are unique immunomodulatory innate T-cells with an invariant TCR recognizing glycolipids presented on MHC class-I-like CD1d molecules. Activated iNKT rapidly secrete pro-and anti-inflammatory cytokines, potentiate immunity, and modulate inflammation. Here, we report the effects of in vivo iNKT activation in Mauritian-origin cynomolgus macaques by a humanized monoclonal antibody, NKTT320, that binds to the invariant region of the iNKT TCR. NKTT320 led to rapid iNKT activation, increased polyfunctionality, and elevation of multiple plasma analytes within 24 hours of administration. Flow cytometry and RNA-Seq confirmed downstream activation of multiple immune subsets, enrichment of JAK/STAT and PI3K/AKT pathway genes, and upregulation of inflammation-modulating genes. NKTT320 also increased iNKT frequency in adipose tissue without iNKT anergy. Our data indicate that NKTT320 has a sustained effect on in vivo iNKT activation, potentiation of innate and adaptive immunity, and resolution of inflammation, which supports its future use as an immunotherapeutic.
Project description:Lipid overload and adipocyte dysfunction are key to the development of insulin resistance and can be induced by a high-fat diet. CD1d-restricted invariant natural killer T (iNKT) cells have been proposed as mediators between lipid overload and insulin resistance, but recent studies found decreased iNKT cell numbers and marginal effects of iNKT cell depletion on insulin resistance under high-fat diet conditions. Here, we focused on the role of iNKT cells under normal conditions. We showed that iNKT cell–deficient mice on a low-fat diet, considered a normal diet for mice, displayed a distinctive insulin resistance phenotype without overt adipose tissue inflammation. Insulin resistance was characterized by adipocyte dysfunction, including adipocyte hypertrophy, increased leptin, and decreased adiponectin levels. The lack of liver abnormalities in CD1d-null mice together with the enrichment of CD1d-restricted iNKT cells in both mouse and human adipose tissue indicated a specific role for adipose tissue–resident iNKT cells in the development of insulin resistance. Strikingly, iNKT cell function was directly modulated by adipocytes, which acted as lipid antigen-presenting cells in a CD1d-mediated fashion. Based on these findings, we propose that, especially under low-fat diet conditions, adipose tissue–resident iNKT cells maintain healthy adipose tissue through direct interplay with adipocytes and prevent insulin resistance.
Project description:Invariant natural killer T (iNKT) cells are innate-like T cells. Although remarkable advancements in the understanding of iNKT cell development have been made, the underlying molecular programs that guide iNKT cell lineages and the heterogeneity of iNKT subsets remain unclear.
Project description:Invariant natural killer T cells (iNKT) cells are differently distributed in various immune organs. However, it remains unclear whether iNKT cells exhibit phenotypical and functional differences in different peripheral organs and how thymic iNKT migrate to peripheral organs. Hence, characterizing iNKT cells in peripheral organs is important.
Project description:Invariant natural killer T cells (iNKT) cells are innate-like T cells, selected from thymic cortex-resident CD4+CD8+ double positive (DP) thymocytes. Despite major advances in the understanding of iNKT cells development, the heterogeneity of iNKT subsets and underlying molecular programs that guide iNKT cell-lineage remain unclear.
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
Project description:Invariant Natural Killer T (iNKT) cells are a unique subset of T lymphocytes with a memory like phenotype which express invariant T cell receptor (TCR) chain comprised of a Vα14-Jα18 rearrangement in mice. In the present study, we characterize the transcriptomes of thymic iNKT cells at the single cell level to reveal the underlying metabolic adaptation that exists over the course of iNKT cell development.
Project description:Invariant Natural killer T (iNKT) cells are a separate lineage of T lymphocytes with innate effector functions. They express an invariant TCR specific for lipids presented by CD1d and their development and effector differentiation rely on a unique gene expression program. We asked whether this program includes microRNAs, small non-coding RNAs that regulate gene expression posttranscriptionally and play key role in the control of cellular differentiation programs. We identified a miRNA profile specific for iNKT cells, which exhibits features of activated/effector T lymphocytes.
Project description:Regulatory B cells (Breg) express high levels of CD1d that presents lipid antigens to invariant natural killer T (iNKT) cells. The function of CD1d in Breg biology and iNKT cell activity during inflammation remains unclear. Here we show, using chimeric mice, cell depletion and adoptive cell transfer, that CD1d-lipid presentation by Bregs induces iNKT cells to secret IFN-γ to contribute, partially, to the down-regulation of T helper (Th)1 and Th17 adaptive immune responses for ameliorating experimental arthritis. Mice lacking CD1d-expressing B cells develop exacerbated diseases compared to wild-type mice, and fail to respond to α-galactosylceramide treatment. Absence of lipid presentation by B cells causes altered activation of iNKT cells, with disruption of regulatory pathways including those involved in metabolism and cytokine responses. Thus, we identify an IL-10-independent mechanism by which Bregs restrain excessive inflammation via lipid presentation.