RESUMO
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 preprogrammed during their thymic differentiation. How this program is initiated is currently unclear. Here, we show that the transcription factor BCL-6 was transiently expressed in iNKT cells upon exit from positive selection and was required for their proper development beyond stage 0. Notably, development of MAIT cells was also impaired in the absence of Bcl6. BCL-6-deficient iNKT cells had reduced expression of genes that were associated with the innate T cell lineage, including Zbtb16, which encodes PLZF, and PLZF-targeted genes. BCL-6 contributed to a chromatin accessibility landscape that was permissive for the expression of development-related genes and inhibitory for genes associated with naive T cell programs. Our results revealed new functions for BCL-6 and illuminated how this transcription factor controls early iNKT cell development.
Assuntos
Cromatina/metabolismo , Células T Invariantes Associadas à Mucosa/imunologia , Células T Matadoras Naturais/imunologia , Proteínas Proto-Oncogênicas c-bcl-6/metabolismo , Animais , Diferenciação Celular , Células Cultivadas , Seleção Clonal Mediada por Antígeno , Regulação da Expressão Gênica no Desenvolvimento , Imunidade Inata , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteína com Dedos de Zinco da Leucemia Promielocítica/genética , Proteínas Proto-Oncogênicas c-bcl-6/genéticaRESUMO
The WNT/ß-catenin signaling pathway controls a plethora of biological processes throughout animal development and adult life. Because of its fundamental role during animal lifespan, the WNT pathway is subject to strict positive and negative multi-layered regulation, while its aberrant activity causes a wide range of pathologies, including cancer. At present, despite the inroads into the molecules involved in WNT-mediated transcriptional responses, the fine-tuning of WNT pathway activity and the totality of its target genes have not been fully elucidated. Over the past few years, long non-coding RNAs (lncRNAs), RNA transcripts longer that 200nt that do not code for proteins, have emerged as significant transcriptional regulators. Recent studies show that lncRNAs can modulate WNT pathway outcome by affecting gene expression through diversified mechanisms, from the transcriptional to post-translational level. In this review, we selectively discuss those lncRNA-mediated mechanisms we believe the most important to WNT pathway modulation.