We have previously demonstrated that hMSCs transplanted into the MM region of developing rat embryos at embryonic day (E) 11.5 resulted in the differentiation of chimeric nephrons, containing hMSC-derived mesangial cells, tubular epithelial cells, and podocytes, all of which are derivatives of the MM [1], [2] and [3]. However, the transplanted hMSCs were unable to differentiate into derivatives of the UB. This suggests that for differentiating hMSCs into signal transducer and activator of transcription 5 (322-343) acetyl of the collecting duct system, hMSC-derived UB must be generated by their transplantation into the UB progenitor region. Thus, instead of mammalian embryos, we focused on using chicken embryos that are easier to be manipulated and cultured than mammalian embryos.
Mammalian BMPs can direct chicken cells to differentiate into ectopic cartilage in ovo [6]. In addition, somites of mouse embryos are known to differentiate into dermis, cartilage, and skeletal muscle in chicken embryos [7]. These results suggest that undifferentiated mammalian cells can differentiate properly in chicken embryos and thus that the hMSCs transplanted into the chicken UB progenitor region would be expected to have the potential to differentiate into derivatives of the UB progenitors under the control of local signals.