Decreasing immunogenicity of ESC derived cardiomyocytes (73.1)

Abstract

Abstract One of the major obstacles to repair damaged myocardium with embryonic stem cell derived cardiomyocytes (ESC-CM) is their rejection by non-syngeneic hosts. We aimed to reduce the immunogenicity of these cells by downregulation of MHC class I molecules (MHC-I) on their surface. Cardiomyocytes were derived from mouse ESC in which puromycin resistance gene is driven by a cardiac-specific promoter. They formed beating cardiomyocyte layers and expressed cardiac specific proteins. Interferon gamma treatment was used to mimic the effects of inflammatory stimuli on the expression of MHC-I. Transduction of ESC-CM with beta-2-microglobulin shRNA decreased expression of MHC-I in both interferon gamma-treated and untreated samples. When MHC-I downregulated ESC-CM were used as in vitro targets, activation of cognate T-lymphocytes was significantly reduced. Moreover, in vivo, MHC-I downregulated cells exhibited improved survival when injected i.p. into allogeneic, but not to syngeneic mice. To confirm that this strategy can be used for different cell types, the results were verified using W19 fibroblasts. In the past, ESC-CM have been shown to improve ischemic myocardium in syngeneic or immunocompromised animals. Inhibition of MHC-I via shRNA offers a simple approach to minimize the immunogenicity of these cells for use in allo- or xenogeneic recipients. Extension of this methodology to ESC of larger mammals can provide a source of less immunogenic cardiomyocytes for human heart repair.