Project description:Innate T cells, including invariant natural killer T (iNKT) and mucosal-associated innate T (MAIT) cells, are a heterogeneous T lymphocyte population with effector properties pre-programmed during their thymic differentiation. How this program is initiated is currently unclear. Here, we show that the transcription factor BCL6 is transiently expressed in iNKT cells upon exit from positive selection and is required for their proper development beyond stage 0. Notably, development of MAIT cells is also impaired in Bcl6-deficient mice. We found that BCL6 regulates the expression of genes that are associated with the innate T cell lineage, including PLZF and its targets. BCL6 contributes to a chromatin accessibility landscape that is permissive for the expression of development-related genes and inhibitory for genes associated with naïve T cell programs. Our results reveal novel functions for BCL6 and indicate that this transcription factor controls the inception of innate T cell lineage programming.
Project description:Innate T cells, including invariant natural killer T (iNKT) and mucosal-associated innate T (MAIT) cells, are a heterogeneous T lymphocyte population with effector properties pre-programmed during their thymic differentiation. How this program is initiated is currently unclear. Here, we show that the transcription factor BCL6 is transiently expressed in iNKT cells upon exit from positive selection and is required for their proper development beyond stage 0. Notably, development of MAIT cells is also impaired in Bcl6-deficient mice. We found that BCL6 regulates the expression of genes that are associated with the innate T cell lineage, including PLZF and its targets. BCL6 contributes to a chromatin accessibility landscape that is permissive for the expression of development-related genes and inhibitory for genes associated with naïve T cell programs. Our results reveal novel functions for BCL6 and indicate that this transcription factor controls the inception of innate T cell lineage programming.
Project description:Innate lymphoid cells (ILC) are tissue-resident effector cells with important roles in tissue homeostasis, protective immunity and inflammatory disease. Here we investigated the role of the transcription factor Bcl6 in small intestinal innate lymphoid cells. Specifically, we performed single-cell RNA-seq on total small intestine lamina propria ILCs from tamoxifen-treated Id2-CreERT2 ROSA26-tdRFP Bcl6-fl/fl mice and Id2-CreERT2 ROSA26-tdRFP controls.
Project description:Using microarrays, we compared the changes in levels of gene expression between wildtype and Bcl6 KO macrophages in the absence or presence of LPS. Total RNA was obtained from WT and Bcl6 KO unstimulated and LPS-stimulated primary bone marrow-derived macrophages
Project description:Innate lymphoid cells (ILC) are tissue-resident effector cells with important roles in tissue homeostasis, protective immunity and inflammatory disease. Current nomenclature divides ILC into subsets based on the expression of master transcription factors and effector cytokine programs. In mucosal barrier tissues, group 3 ILC (ILC3) have been defined by the expression of the master transcription factor RORgt. However, ILC3 can be further subdivided into two major subsets – natural cytotoxicity receptor-expressing (NCR+) ILC3 and lymphoid tissue inducer (LTi)-like ILC3 which share type 3 effector modules but also exhibit significant ontological, transcriptional, phenotypic and functional heterogeneity. In particular, LTi-like ILC3 exhibit effector functions not typically associated with other RORgt-expressing lymphocytes, provoking the hypothesis that other master transcription factors may contribute to LTi-like ILC3 biology. Here we identify Bcl6 as an LTi-like ILC3 associated transcription factor in both mice and humans. Deletion of Bcl6 led to dysregulation of the LTi-like ILC3 transcriptional program and changes to subset-specific phenotypic markers and effector functions. Strikingly, loss of Bcl6 enhanced expression of the type 3 effector cytokines IL-17A and IL-17F in LTi-like ILC3, which was found to be in part dependent upon the commensal microbiota. Together these findings implicate Bcl6 as an ILC3 subset-defining transcription factor and part of a network that confers phenotype and function on LTi-like ILC3. Our study further provides a missing link to redefine analogous immune modules in innate and adaptive lymphocyte responses.
Project description:Most small-molecule protein degraders act as interface stabilizers ‘molecular glues’ between E3 ubiquitin ligases and target proteins to induce ternary complex formation and ubiquitin-dependent target protein degradation. Here we report polymerization as a novel mechanism for small molecule-induced degradation. Using functional screens in combination with molecular and biochemical assays, we found that BI-3802, which binds to the BTB domain of the oncogenic transcription factor BCL6, induces polymerization of BCL6 into regular helical structures in vitro and foci in vivo. Polymerization precedes degradation by the SIAH1 E3 ubiquitin ligase. Hereby, a VxP amino acid motif on BCL6, distal from the drug-binding BTB domain, is required for SIAH1 binding, ubiquitination and BI-3802-induced degradation. Our findings propose that small molecule-induced polymerization is not only a new modality for targeted protein degradation, but also provides synthetic biology with a tool for tunable protein polymerization and opens new avenues for future drug design.
Project description:Using microarrays, we compared the changes in levels of gene expression between wildtype and Bcl6 KO macrophages in the absence or presence of LPS.