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:Natural Killer (NK) cells play a central role in cell-mediated immune response to cancer. In previous studies number and function of NK-cells have been shown to be positively correlated with HCC outcome. In this study, we have performed a genetic expression analysis comparing mRNA expression by NK cells from tumor samples derived from HCC patients to NK cells infiltrating the liver counterpart and to NK cells in the normal liver as controls. The bioinformatic analysis has been completed by an immunophenotypic study, functional analysis and metabolic assessment of the infiltrating NK cells. It is known that NK cells may present functional defects in HCC patients however previous studies have not systematically address the molecular mechanisms associated with these defects by an unbiased genetic expression study. We have identified altered cellular pathways and hypothesized possible mechanisms that could be targeted for restoring an immune-protective NK cell response.
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.
