Matched Developmental Timing of Donor Cells with the Host Is Crucial for Chimera Formation

Abstract

SummaryChimeric mice have been generated by injecting pluripotent stem cells into morula-to-blastocyst stage mouse embryo or by introducing more mature cells into later stage embryos that correspond to the differentiation stage of the donor cells. It has not been rigorously tested, however, whether successful chimera formation requires the developmental stage of host embryo and donor cell to be matched. Here, we compared the success of chimera formation following injection of primary neural crest cells (NCCs) into blastocysts or of embryonic stem cells (ESCs) into E8.5 embryos (heterochronic injection) with that of injecting ESCs cells into the blastocyst or NCCs into the E8.5 embryos (isochronic injection). Chimera formation was efficient when donor and host were matched, but no functional chimeric contribution was found in heterochronic injections. This suggests that matching the developmental stage of donor cells with the host embryo is crucial for functional engraftment of donor cells into the developing embryo.

Adaptation within embryonic and neonatal heart environment reveals alternative fates for adult c-kit+ cardiac interstitial cells

“…Following this alternative strategy, delivery of cCIC to cardiogenic fetal and neonatal environments should allow for prolonged presence and tracking to assess phenotypic adaptation. Precedents for this concept involving ESC chimeras or fate‐mapping of cells introduced into cardiogenic environments demonstrate that early developmental stages are particularly suited for assessing pluripotency and cellular plasticity. Thus, three distinct stages of embryonic, fetal, and neonatal development were used to interrogate phenotypic adaptation of cultured cCICs.…”

“…Efficient chimeric competency relies on pairing donor cell autonomous developmental timing with host organ developmental stages, a synchrony which is absent when donated cCIC are met with fetal or neonatal environments. Although cCIC fail to demonstrate multipotential commitment, the neonatal environment does allow for prolonged persistence.…”

Stem Cells, Genome Editing, and the Path to Translational Medicine

“…In both experimental paradigms, the overall contribution of human cells is rather limited. This could be caused by technical challenges related to transplantation (Cohen et al, 2016; Nagashima et al, 2014), imperfect adjustment of developmental timing between donor and host cells at the time of transplantation (Cohen et al, 2018) or species-specific differences.…”

“…Using sophisticated immunodeficient mouse models or humanized hosts carrying fully functional human immune system or genetically engineered human specific growth factors could enhance the chimeric contribution of human cells (Zhang et al, 2004). Recent intraspecies chimera experiments suggest that matched developmental timing is crucial for successful contributions by transplanted cells (Cohen et al, 2018). It is still unclear, whether inhibition of cell death (e.g.…”

“…It is still unclear, whether inhibition of cell death (e.g. overexpression of antiapoptotic factors such as Bcl2) is sufficient to relax this requirement (Cohen et al, 2018; Masaki et al, 2016). …”