Cross-species single-cell transcriptomic analysis reveals pre-gastrulation developmental differences among pigs, monkeys, and humans

TLDR

Interspecies blastocyst complementation can generate human tissues in animal hosts, but differences in embryo development between humans and host species may limit chimera efficiency. The study aimed to elucidate these developmental differences by constructing a comprehensive single‑cell transcriptomic atlas of early pig embryogenesis and comparing its epiblast with those of humans and monkeys. Using single‑cell RNA sequencing, the authors profiled pig embryos at pre‑gastrulation stages and performed systematic cross‑species comparisons of pluripotency, metabolism, epigenetics, surface proteins, and trophectoderm development. They discovered species‑specific divergences in pluripotency progression, metabolic transition, epigenetic and transcriptional regulation, cell‑surface markers, and trophectoderm maturation that likely impede human‑pig cell integration, offering insights to improve chimerism and enable functional human organ generation in pigs.

Abstract

Abstract Interspecies blastocyst complementation enables organ-specific enrichment of xenogeneic pluripotent stem cell (PSC) derivatives, which raises an intriguing possibility to generate functional human tissues/organs in an animal host. However, differences in embryo development between human and host species may constitute the barrier for efficient chimera formation. Here, to understand these differences we constructed a complete single-cell landscape of early embryonic development of pig, which is considered one of the best host species for human organ generation, and systematically compared its epiblast development with that of human and monkey. Our results identified a developmental coordinate of pluripotency spectrum among pigs, humans and monkeys, and revealed species-specific differences in: (1) pluripotency progression; (2) metabolic transition; (3) epigenetic and transcriptional regulations of pluripotency; (4) cell surface proteins; and (5) trophectoderm development. These differences may prevent proper recognition and communication between donor human cells and host pig embryos, resulting in low integration and survival of human cells. These results offer new insights into evolutionary conserved and divergent processes during mammalian development and may be helpful for developing effective strategies to overcome low human–pig chimerism, thereby enabling the generation of functional human organs in pigs in the future.