Maintenance of Hypoimmunogenic Features via Regulation of Endogenous Antigen Processing and Presentation Machinery

Abstract

Universally acceptable donor cells have been developed to address the unmet need for immunotypically matched materials for regenerative medicine. Since forced expression of hypoimmunogenic genes represses the immune response, we established universal pluripotent stem cells (PSCs) by replacing endogenous β2-microglobulin (β2m) with β2m directly conjugated to human leukocyte antigen (HLA)-G, thereby simultaneously suppressing HLA-I expression and the natural killer (NK) cell-mediated immune response. These modified human PSCs retained their pluripotency and differentiation capacity; however, surface presentation of HLA-G was absent from subsequently differentiated cells, particularly cells of neural lineages, due to the downregulation of antigen processing and presentation machinery (APM) genes. Induction of APM genes by overexpression of NLR-family CARD domain-containing 5 (NLRC5) or activator subunit of nuclear factor kappa B (NF-κB) heterodimer (RelA) recovered the surface expression of HLA-G and the hypoimmunogenicity of neural cells. Our findings enhance the utility of hypoimmunogenic cells as universal donors and will contribute to the development of off-the-shelf stem-cell therapeutics.

CRISPR-Cas9 immune-evasive hESCs are rejected following transplantation into immunocompetent mice

“…One caveat is that cells that lack MHC proteins on their surface are susceptible to natural killer (NK) cell-mediated killing ( Long et al, 2013 ). Hence, many tactics have been explored to reduce NK killing by either preserving the expression of less polymorphic MHC molecules ( Taylor et al, 2012 ; Gornalusse et al, 2017 ; Han et al, 2019 ; Shi et al, 2020 ; An et al, 2022 ) or by overexpressing PDL-1 ( Han et al, 2019 ) or CD47 ( Deuse et al, 2019 ; Han et al, 2019 ; Deuse et al, 2021 ; Feng et al, 2023 ). Preservation of less polymorphic MHC molecules still requires immune matching, but it facilitates the identification process of a donor and can still maintain some of the favorable parts of the immune response, such as in the case of infection.…”