In vitro mimicking of humanized cardiogenesis under porcine condition

Background: One promising strategy to generate humanized organs is through embryo complementation by injecting human pluripotent stem cells (PSCs) into gene-edited porcine embryos. This strategy is predicated on how human cells adapt to a porcine environment, which has a body temperature of 38.5 °C, much higher than that of the human body. Results: Here, we present an in vitro model to address this problem by coculturing human and porcine induced PSCs at 38.5 °C and inducing them to generate cardiomyocytes. We show that co-cultured human cells can differentiate into myocardial features with the help of porcine cells at an enhanced differentiation rate. Mechanistically, we show that co-cultured human cells respond to elevated temperature by activating a stress response with the PI3K-Akt-mTOR signaling pathway activated. Moreover, a model mimicking embryo complementation by knocking out MYH6 in pig PSCs reveals the potential risk of porcine cells leaking into human-derived tissues. Conclusions: Together, our studies present a novel model system to evaluate human and porcine cell co-differentiation that may guide the planning of in vivo experiments.