T cell immunotherapy is poised to be a major player in the future of medicine. The success of CD19 CAR T cells in acute lymphoblastic leukemia has been impressive and gives a glimpse of what the next generation of engineered T cells may be capable of. In the future, CAR-targeted T cells may be valuable immunotherapy for more than just cancer. In particular, targeted T regulatory cell therapy is a promising possibility for treatment of autoimmune conditions and tolerance induction in transplant recipients. Current methods of CAR T cell production are dependent on laborious isolation, modification, and expansion steps on a per-patient basis. This makes them highly expensive with little possibility of an off-the-shelf product. Induced pluripotent stem cells (iPSC) allow the reprogramming of adult somatic cells to a stem-cell like fate from patients with specific MHC haplotypes to overcome this issue. The combination of MHC-banked iPSCs and CAR technology sets the stage for a renewable and highly controllable off-the-shelf T cell therapeutic. However, efforts to differentiate iPSCs into T cells have struggled with the production of hematopoietic progenitors with robust T cell potential and a blockade in T cell maturation at the CD4/8 double positive stage. In this proposal we demonstrate the marked impact of modulating the NOTCH signaling pathway on T-capable progenitor output. We propose to combine this success with single-cell RNAseq to reveal the true identity of the T cell progenitor. This work will uncover key signaling pathways and answer lingering questions about the nature of iPSC- derived hematopoietic progenitors. It will also leverage improved efficiency in differentiation cultures. In addition, we propose to use temporally controlled expression of CARs with a range of antigen affinities during T cell differentiation to bypass their developmental blockade and drive maturation into functional T cells. These two synergistic but not dependent goals will be a vital and powerful step toward truly functional iPSC- derived T cells and would also open the door for exploring signals necessary to drive CD4 helper T cell commitment and T reg lineage specification.

Public Health Relevance

This fellowship proposal focuses on robust and efficient differentiation of mature T cells from induced pluripotent stem cells by modulating the NOTCH signaling pathway and using chimeric antigen receptors to bypass the developmental impass at the double positive (CD4+/CD8+) stage. It also aims to identify the identity of the T cell progenitor in iPSC-derived hematopoietic differentiation, a question of significant import for the field as a whole. Together these synergistic goals will allow the derivation of iPSC-derived functional T cells with a defined specificity opening the door for therapeutic applications of these cells.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
5F32HL149605-02
Application #
9970164
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Welniak, Lisbeth A
Project Start
2019-06-01
Project End
2021-05-31
Budget Start
2020-06-01
Budget End
2021-05-31
Support Year
2
Fiscal Year
2020
Total Cost
Indirect Cost
Name
Boston University
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118