Generation of Chimeric Rhesus Monkeys

Abstract

Summary Totipotent cells in early embryos are progenitors of all stem cells and are capable of developing into a whole organism, including extraembryonic tissues such as placenta. Pluripotent cells in the inner cell mass (ICM) are the descendants of totipotent cells and can differentiate into any cell type of a body except extraembryonic tissues. The ability to contribute to chimeric animals upon reintroduction into host embryos is the key feature of murine totipotent and pluripotent cells. Here, we demonstrate that rhesus monkey embryonic stem cells (ESCs) and isolated ICMs fail to incorporate into host embryos and develop into chimeras. However, chimeric offspring were produced following aggregation of totipotent cells of the 4-cell embryos. These results provide insights into the species-specific nature of primate embryos and suggest that a chimera assay using pluripotent cells may not be feasible.

Interspecies chimeras for human stem cell research

“…When EpiSCs were transplanted into pre-implantation embryos, they were unable to form chimeras, unlike rodent ESCs (Brons et al, 2007;Tesar et al, 2007). Consistent with this, chimera formation was also not possible when monkey ESCs were transplanted into monkey embryos (Tachibana et al, 2012). On the other hand, it is possible to generate chimeras by transplanting EpiSCs into eggcylinder stage embryos, which is the developmental stage when the epiblast is obtained to establish EpiSCs (Huang et al, 2012;Kojima et al, 2014).…”

The transcriptional regulation of pluripotency

“…Because hESCs resemble EpiSCs more than mESCs, despite also having been derived from pre-implantation blastocysts, it is believed that during the hESC derivation process, pre-hESCs may have progressed into a more developmentally advanced EpiSC-like state [124]. In support of this 'primed' pluripotent state of hESCs, nonhuman primate ESCs from rhesus monkeys, like mouse EpiSCs, are unable to contribute to chimera formation [125].…”

Methods for creating transgenic primates

“…Embryonic cell lines have been established in several species of primates 8,9 , but until very recently genetic modification and subsequent injection of these cells into blastocysts failed to result in the development of a chimeric organism 10 . However, by manipulating the cell culture conditions, Chen and colleagues were able to breakdown this barrier and successfully incorporate ESCs into a developing embryo, resulting in chimeric Targeted gene integration to create transgenic primates Previous NHP models relied on gene expansion or increase in gene copy number in order to establish a disease state.…”