Epigenetic reprogramming of terminal T cell differentiation via DNMT1 inhibition reverses terminal DNA methylation and enhances multipotency 2259880

Introduction The effectiveness of T cell-based immunotherapy is limited due to T cell exhaustion, a state of impaired cytotoxicity, diminished cytokine production, and restricted proliferative capacity during chronic antigen exposure. Epigenetic modifications, such as the acquisition of repressive DNA methylation, sustain T cell exhaustion. Here, we investigate the role of hypomethylating agents in reversing T cell dysfunction via DNA demethylation. We hypothesize that using a selective inhibitor of DNA methyltransferase 1 (DNMT1i), GSK-3685032, can overcome the fate restrictions unique to terminally differentiated T-cells. Our preliminary data show that the fate and subset specificity of human and mouse T-cells can be epigenetically altered to mediate the reversal of repressive epigenetic programs. Methods Methylation profiling revealed that DNMT1i treatment results in robust loss of DNA methylation, notably at critical memory and stem-associated gene loci including TCF7 and LEF1. Results Notably, DNMT1i-treated T cells that underwent division had decreased methylation coupled to heightened multipotency and plasticity. Single-cell transcriptomics post DNMT1i treatment reinforced our findings by revealing a unique subset of memory T cells that have homing potential and a long-lived memory gene signature. Conclusion Collectively, we describe an epigenetic approach that facilitates the reversal of repressive DNA methylation and are now using this approach to alter the fate of T cell subsets for immunotherapy. Funding Source R01CA237311 Topic Categories Lymphocyte Differentiation and Peripheral Maintenance (LYM)