G9a/GLP Inhibition Promotes T Cell Development from Pluripotent Stem Cells [ATAC-Seq]

Elucidating mechanisms of T cell development can guide in vitro T cell differentiation from Pluripotent Stem Cells (iPSCs) and inform off-the-shelf T cell-based immunotherapies. Using a stroma-free human iPSC-T cell differentiation platform, we screened for epigenetic modulators that govern T cell specification and identified the H3K9-directed histone methyltransferases G9a/GLP as repressors of T cell fate. We show that G9a/GLP controls the cell fate decision between myeloid and lymphoid lineages in hematopoietic stem and progenitor cells (HSPCs). Inhibition of G9a/GLP promotes the production of lymphoid cells during zebrafish embryonic hematopoiesis, demonstrating the evolutionary conservation of G9a/GLP function. Importantly, chemical-induced epigenetic reprogramming via G9a/GLP inhibition facilitates the generation of robust iPSC-T cells that bear transcriptional similarity to peripheral blood αβ T cells. When engineered to express Chimeric Antigen Receptors, the epigenetically engineered iPSC-T cells exhibit enhanced antitumor activity both in vitro and in a xenograft mouse model.