Description

Enhancing lymphoid potential from human pluripotent stem cells via epigenetic modulation

Linda T. Vo¹, Melissa A. Kinney¹, Xin Liu², Yuannyu Zhang^2,3, Patricia M. Sousa¹, Jessica Barragan¹, Areum Han¹, Deepak K. Jha¹, Marcella Cesana¹, Zhen Shao³, Stuart H. Orkin^1,4, Sergei Doulatov⁵, Jian Xu², and George Q. Daley^1,4*

¹Division of Hematology/Oncology, Boston Children’s Hospital, ²Children’s Medical Center Research Institute, Department of Pediatrics, University of Texas Southwestern Medical Center, ³Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, ⁴Howard Hughes Medical Institute, ⁵Division of Hematology, Department of Medicine, University of Washington

*Corresponding author

Immunotherapy has rapidly emerged as a promising treatment for many different types of cancer. Ongoing clinical trials continue to validate the efficacy of T cell-based cancer immunotherapy, such as chimeric antigen receptor “CAR” T-cells, as a valid therapeutic approach. As such, new sources of both autologous and “off the shelf” T cells available in large qualities would be invaluable to widespread application of these treatments. Human induced pluripotent stem cells (iPSCs) represent a potentially inexhaustible source of clinically useful cell types. Previous studies have demonstrated the feasibility of generating T cells from iPSCs, but yields have been low due to the inefficiency of lymphoid differentiation. Here, we report a cell engineering platform capable of generating large numbers of T cells from iPSCs using a combination of transcription factors and chromatin modifiers. We initially performed a loss-of-function screen to identify regulators that enhance lymphoid potential in iPSC-derived hematopoietic progenitors. We found that repression of the Polycomb group protein EZH1 uniquely enhanced multilineage hematopoietic output from human iPSCs in vitro and in vivo. EZH1 directly modulates the expression of HSC and lymphoid genes in iPSC-derived hematopoietic progenitors and its knockdown enhances chromatin accessibility of these loci. EZH1 inhibition enables the continuous generation of T cell progenitors from human iPSCs, representing a platform that can be further optimized for clinical translation. Together, this work highlights the utility of chromatin modifiers as cell engineering targets to enhance blood differentiation from human iPSCs.