Pax6 Is a Human Neuroectoderm Cell Fate Determinant

Abstract

SUMMARY The transcriptional regulation of neuroectoderm (NE) specification is unknown. Here we show that Pax6 is uniformly expressed in early NE cells of human fetuses and those differentiated from human embryonic stem cells (hESCs). This contrasts the later expression of Pax6 in restricted mouse brain regions. Knockdown of Pax6 blocks NE specification from hESCs. Overexpression of either Pax6a or Pax6b, but not Pax6 PD, triggers hESC differentiation. However, only Pax6a converts hESCs to NE. In contrast, neither loss nor gain of function of Pax6 affects mouse NE specification. Both Pax6a and Pax6b bind to pluripotent gene promoters but only Pax6a binds to NE genes during human NE specification. These findings indicate that Pax6 is a transcriptional determinant of the human NE and suggest that Pax6a and Pax6b coordinate with each other in determining the transition from pluripotency to the NE fate in human by differentially targeting pluripotent and NE genes.

Human midbrain precursors activate the expected developmental genetic program and differentiate long-term to functional A9 dopamine neurons in vitro. Enhancement by Bcl-XL

“…In the mouse embryo, Pax6 is expressed in the neuroectoderm of the FB and hindbrain [64]. In human stem cells PAX6 acts as a determinant of neuroectoderm fate [65][66][67]. Consistently, some expression was detected in hVMl cells, but it was higher in hNSl cells (Fig.…”

ADAR1 is required for differentiation and neural induction by regulating microRNA processing in a catalytically independent manner

“…At 10 and 17 days of neural differentiation, hESC-derived primitive and definitive neuroepthelial (NE) cells with scramble shRNA treatment presented typical columnar NE morphology and were organized into rosettes [36][37][38] (Figure 1D and 1E), similar to the structure of NE cells from WT hESC induction (as discussed below and data not shown). Noticeably, although differentiating hESCs with stable ADAR1 knockdown also formed rosette-like structures, these cells expressed low levels of PAX6, SOX1 and FOXG1 ( Figure 1D and Supplementary information, Table S1), and formed much Table S1.…”

“…As ADAR1 knockdown has little effect on pluripotency, we then proceeded to study the effect of ADAR1 deficiency on differentiation with a protocol summarized in Supplementary information, Figure S2A [36][37][38]. Briefly, hESCs were induced into the neural lineage by generating EBs followed by culturing in neural medium.…”

MSX2 mediates entry of human pluripotent stem cells into mesendoderm by simultaneously suppressing SOX2 and activating NODAL signaling

“…Similar species-specific functions of cell fate-specifying factors have been reported previously. For example, Zhang et al [64] demonstrated that PAX6 is a key determinant of neuroectoderm cell fate in hPSCs but is not involved in mouse neuroectoderm specification.…”