Embryonic stem cells neural differentiation qualifies the role of Wnt/β-Catenin signals in human telencephalic specification and regionalization

Abstract

Wnt-ligands are among key morphogens that mediate patterning of the anterior territories of the developing brain in mammals. We qualified the role of Wnt-signals in regional specification and subregional organization of the human telencephalon using human pluripotent stem cells (hPSCs). One step neural conversion of hPSCs using SMAD inhibitors leads to progenitors with a default rostral identity. It provides an ideal biological substrate for investigating the role of Wnt signaling in both anteroposterior and dorso-ventral processes. Challenging hPSCneural derivatives with Wnt-antagonists, alone or combined with sonic hedgehog (Shh), we found that Wntinhibition promote both telencephalic specification and ventral patterning of telencephalic neural precursors in a dose-dependent manner. Using optimal Wnt-antagonist and Shh-agonist signals we produced human ventraltelencephalic precursors, committed to differentiation into striatal projection neurons both in vitro and in vivo after homotypic transplantation in quinolinate-lesioned rats. This study indicates that sequentially organized Wntsignals play a key role in the development of human ventral telencephalic territories from which the striatum arise. In addition, the optimized production of hPSCderived striatal cells described here offers a relevant biological resource for exploring and curing Huntington disease.

Activin A directs striatal projection neuron differentiation of human pluripotent stem cells

“…The activin-induced gene expression changes are distinct from those induced by Shh, which is the key molecule employed by published striatal differentiation protocols (Aubry et al, 2008;Ma et al, 2012;Nicoleau et al, 2013). These studies and the current work show that Shh elicited a strong inductive effect on MGE regulator genes, such as NKX2.1, and gene markers expressed in both the MGE and LGE (e.g.…”

“…Shh was first applied in an hESC differentiation protocol for generating DARPP32 + neurons (Aubry et al, 2008) and again recently with or without combinatorial inhibition of Wnt signalling (Ma et al, 2012;Carri et al, 2013;Nicoleau et al, 2013). The effect of Shh on the generation of ventral forebrain cellular phenotypes might be due to the derepression of GLI3, which is a key factor that dorsalises hESC-derived neural progenitors (Li et al, 2009).…”

Canonical and noncanonical Wnt signaling in neural stem/progenitor cells

“…However, many other reports highlight the role of canonical Wnt signaling in stem/progenitor cell maintenance, rather than induction of differentiation. For example, Wexler et al showed that baseline -catenin signaling represses neuronal differentiation in human NSCs [131], and another study reported that inhibition of Wnt/ -catenin signaling using Dkk-1 or the tankyrase inhibitor XAV939 promotes neural precursor specification [164]. Moreover, GSK-3 inhibition, which induces stem cell renewal and sustains the expression of pluripotency markers [16], is a widely used tool to expand neural progenitors 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 [154][155][156], and bFGF treatment of hES and iPS cells, which maintains the undifferentiated state, activates canonical Wnt signaling through inhibition of GSK-3 [165].…”

Transplantation in HD: Are We Transplanting the Right Cells?

“…Specifically, addition of both noggin and SB431542 (a BMP inhibitor and Activin/Nodal inhibitor, respectively) was shown to increase the yield of cells expressing the neural markers Pax6, Foxg1 and Sox1, whilst expression of the pluripotent marker Oct4 decreased [72]. This method is now widely used as the first stage in the generation of neural cells from PSCs and has successfully been applied to the initial stages of striatal differentiation protocols [73][74][75] (discussed below, and see Table 1). …”