Genome editing HLA alleles for a pilot immunocompatible hESC line in a Chinese hESC bank for cell therapies

by Selleckchem | Sep 21 2023

Robust allogeneic immune reactions after transplantation impede the translational pace of human embryonic stem cells (hESCs)-based therapies. Selective genetic editing of human leucocyte antigen (HLA) molecules has been proposed to generate hESCs with immunocompatibility, which, however, has not been specifically designed for the Chinese population yet. Herein, we explored the possibility of customizing immunocompatible hESCs based on Chinese HLA typing characteristics. We generated an immunocompatible hESC line by disrupting HLA-B, HLA-C, and CIITA genes while retaining HLA-A*11:01 (HLA-A*11:01-retained, HLA-A11R ), which covers ~21% of the Chinese population. The immunocompatibility of HLA-A11R hESCs was verified by in vitro co-culture and confirmed in humanized mice with established human immunity. Moreover, we precisely knocked an inducible caspase-9 suicide cassette into HLA-A11R hESCs (iC9-HLA-A11R ) to promote safety. Compared with wide-type hESCs, HLA-A11R hESC-derived endothelial cells elicited much weaker immune responses to human HLA-A11+ T cells, while maintaining HLA-I molecule-mediated inhibitory signals to natural killer (NK) cells. Additionally, iC9-HLA-A11R hESCs could be induced to undergo apoptosis efficiently by AP1903. Both cell lines displayed genomic integrity and low risks of off-target effects. In conclusion, we customized a pilot immunocompatible hESC cell line based on Chinese HLA typing characteristics with safety insurance. This approach provides a basis for establishment of a universal HLA-AR bank of hESCs covering broad populations worldwide and may speed up the clinical application of hESC-based therapies.

Comments:

The passage you provided describes a study conducted to address the challenge of immune reactions following the transplantation of human embryonic stem cells (hESCs). These immune reactions can hinder the progress of hESC-based therapies. The researchers aimed to create immunocompatible hESCs specifically designed for the Chinese population by selectively editing human leukocyte antigen (HLA) molecules.

The study focused on Chinese HLA typing characteristics and generated an immunocompatible hESC line by disrupting the HLA-B, HLA-C, and CIITA genes while retaining HLA-A*11:01 (referred to as HLA-A11R). HLA-A11R was found to cover approximately 21% of the Chinese population. The researchers verified the immunocompatibility of HLA-A11R hESCs through in vitro co-culture experiments and confirmed it in humanized mice with established human immunity.

To enhance safety, the researchers further modified the HLA-A11R hESCs by introducing an inducible caspase-9 suicide cassette (iC9-HLA-A11R). This modification allowed the cells to undergo apoptosis efficiently upon exposure to AP1903.

The study demonstrated that endothelial cells derived from HLA-A11R hESCs elicited weaker immune responses compared to those derived from wild-type hESCs when exposed to human HLA-A11+ T cells. However, the HLA-A11R hESC-derived cells maintained HLA class I molecule-mediated inhibitory signals to natural killer (NK) cells, which are important for immune regulation.

Both the HLA-A11R and iC9-HLA-A11R cell lines exhibited genomic integrity and low risks of off-target effects. The researchers concluded that they successfully customized an immunocompatible hESC cell line based on Chinese HLA typing characteristics, with safety measures in place. This approach lays the foundation for establishing a universal HLA-AR (HLA-allele replaced) bank of hESCs that can cover diverse populations worldwide. The findings of this study may contribute to accelerating the clinical application of hESC-based therapies.