Project description:Thymocyte-expressed molecule involved in selection (Themis) was identified as a T cell-specific protein for T cell development. Recently, Themis was found to be required for T cell homeostasis by orchestrating TCR signaling and cytokine, especially γc family cytokine IL-7 signaling in peraphrial CD8+ T cells. Here, our study identifies Themis as a regulator for another γc family cytokine IL-2-induced proliferation. Transcriptomics and metabolomics reveal that Themis regulates Jak-Stat, Akt-mTOR as well as the downstream metabolic pathways. Moreover, how Themis regulates Shp1 phosphatase activity is still controversial. We further demonstrate that Themis negatively regulates Shp1 phosphatase activity on Jak1 and Jak3 to facilitate downstream signaling and subsequently metabolic reprograming, highlighting the importance of Themis in metabolic responses of CD8+ T cells.
Project description:TFH cells play an important role in chronic viral infection by helping B cells produce antibodies. Recent studies have identified a novel CD4+ T cell progenitor population in chronic LCMV infection that sustains the differentiation of TFH and other effector CD4+ T cells. However, the details of this differentiation process remain unclear. Here, we report an unprecedented dual role for Themis in regulating the differentiation of CD4+ T cell progenitors into TFH cells during chronic LCMV infection. Themis expression is strongly upregulated in TFH cells at early stages of infection, and as expected, Themis promotes TFH cell differentiation at this stage. However, unexpectedly, at the late stages of chronic LCMV infection, Themis-deficient CD4+ T cells favored TFH cell differentiation and helped control the virus by enhancing GC responses and antibody production, suggesting that Themis inhibits TFH cell differentiation at this stage. In the late stage we found that Themis inhibits the differentiation of CD4+ T cell progenitors into TFH cells through transcriptional regulation.
Project description:This study aimed to compare the TCRab repertoires from CD8 T cell subsets in a different T cell progression stage in Themis-sufficient and Themis-deficient mice. Analysis of the NGS-derived data revealed an overall reduction of the TCRa repertoire diversity in Themis's absence. In contrast, the CD8 compartment bearing the Va3.2 TCRs in the Themis-deficient model retains higher diversity than the repertoire from the Themis-sufficient counterpart. Furthermore, analysis of CDR3 peptide sequences of Va3.2+ and Va3.2- TCRs disclose the greater contribution of the hydrophobic residues in the former repertoires, indicating enhanced self-reactivity within this CD8+ T cell fraction.
Project description:IL2 and IL15 both utilize IL2Rβ and the common gamma chain (γc) and trigger near-indistinguishable downstream signaling pathways. Yet, IL2 and IL15 differentially regulate T cell metabolism and consequently dictate distinct functional outcomes, with IL2 promoting glycolysis and exhaustion, and IL15 favoring oxidative phosphorylation and long-term persistence. Since TurboCAR.15 variants contain signaling domains derived from IL2Rβ, we sought to determine whether they more closely recapitulated IL2 or IL15 signaling. To this end, gene expression profiles of TurboCAR.15 variants versus BCMA TurboCARs that had been conditioned and cultured in IL2 or IL15 were compared.
Project description:THEMIS is critical for conventional T cell development but its precise molecular function remains elusive. Here we show that THEMIS constitutively associates with the phosphatases SHP-1 and SHP-2. This complex requires the adapter GRB2, which bridges SHP to Themis in a Tyr-phosphorylation-independent fashion. Rather, SHP1 and THEMIS engage with the N-SH3 and C-SH3 domains of GRB2, respectively, a configuration that allows GRB2-SH2 to recruit the complex onto LAT. Coherent with THEMIS-mediated recruitment of SHP to the TCR signalosome, THEMIS knockdown increased TCR-induced TCR- phosphorylation, Erk activation and CD69 expression, however not Lck phosphorylation. This generalized TCR signalling increase led to augmented apoptosis, a phenotype mirrored by SHP-1 knockdown. Remarkably, a KI mutation of Lck Ser59, previously suggested to be key in ERK-mediated resistance towards SHP-1 negative feedback, did not affect TCR signalling nor ligand discrimination in vivo. Thus, THEMIS:SHP complex dampens early TCR signalling by a previously unknown molecular mechanism that favors T cell survival. We discuss possible implications of this mechanism in modulating TCR output signals towards conventional T cell development and differentiation.
Project description:Determine the biochemical cause of impaired development of Themis-deficient thymocytes. We isolated three thymocyte populations (three populations: CD4+CD8+CD5loCD69lo, CD4+CD8+CD5+CD69+, and CD4+CD8-CD24hiH2Klo) from Themis-deficient and WT mice. 8 or 9 individual biological replicates were analyzed for each population. An aliquot of cDNA from each sample was pooled and used as a reference.
Project description:We adopted scRNA-seq to examine whether Themis is required for Tex initiation. To strengthen the rigorousness of scRNA-seq analysis, we contransferred P14 WT and P14 Themis cKO cells, enabling them to experience the same viral burden and inflammatory environment. Then cells from all conditions (including naïve control cells) were combined and subjected to analysis.
Project description:Molecular profiling of cultured CD8+ T cells from mice and treated with either IL2, IL2/SIIKFEKL(TCR), IL2/IL4, or IL2/IL4/SIINFEKL(TCR)
Project description:Transcriptomic profiling of cultured CD8+ T cells from mice and treated with either IL2, IL2/SIINFEKL(TCR), IL2/IL4, or IL2/IL4/SIINFEKL(TCR)