Transmembrane TNF-TNFR2 axis promotes generation of human T cell precursors

The goal of this study is to understand how low level of IRF8 expression promotes the differentiation of human hematopoietic stem and progenitor cells (HSPCs) into T cell precursors. To achieve this, we utilized a construct that encodes IRF8-ERT2 fusion protein where IRF8 activity is tamoxifen-dependent. We extracted genomic DNA from HSPCs that had been co-cultured with OP9-DLL4 stromal cells and tagmented by Tn5 transposase for ATAC-sequencing. This allowed us to determine the impact of low level of IRF8 activity on the chromatin accessibility landscape of differentiating HSPCs. Our analysis found significant opening of chromatin region at the TNF core promoter in the presence of low level of IRF8 activity. HSPCs from 3 donors were transduced with empty vector control or IRF8-ERT2. In each condition, transduced HSPCs were sorted after 4 days of co-culture to obtain two subsets (CD45+GFP+CD7+ cells and CD45+GFP+CD34+CD7- cells) for ATAC-seq.