Rostrocaudal patterning and neural crest differentiation of human pre-neural spinal cord progenitors in vitro.

The spinal cord emerges from a niche of neuromesodermal progenitors (NMPs) formed and maintained by WNT/fibroblast growth factor (FGF) signals at the posterior end of the embryo. NMPs can be generated from human pluripotent stem cells and hold promise for spinal cord replacement therapies. However, NMPs are transient, which compromises production of the full range of rostrocaudal spinal cord identities in vitro. Here we report the generation of NMP-derived pre-neural progenitors (PNPs) with stem cell-like self-renewal capacity. PNPs maintain pre-spinal cord identity for 7-10 passages, dividing to self-renew and to make neural crest progenitors, while gradually adopting a more posterior identity by activating colinear HOX gene expression. The HOX clock can be halted through GDF11-mediated signal inhibition to produce a PNP and NC population with a thoracic identity that can be maintained for up to 30 passages.

Cooper F ，Gentsch GE ，Mitter R ，Bouissou C ，Healy LE ，Rodriguez AH ，Smith JC ，Bernardo AS ... -  《Stem Cell Reports》

Defining the signalling determinants of a posterior ventral spinal cord identity in human neuromesodermal progenitor derivatives.

The anteroposterior axial identity of motor neurons (MNs) determines their functionality and vulnerability to neurodegeneration. Thus, it is a crucial parameter in the design of strategies aiming to produce MNs from human pluripotent stem cells (hPSCs) for regenerative medicine/disease modelling applications. However, the in vitro generation of posterior MNs corresponding to the thoracic/lumbosacral spinal cord has been challenging. Although the induction of cells resembling neuromesodermal progenitors (NMPs), the bona fide precursors of the spinal cord, offers a promising solution, the progressive specification of posterior MNs from these cells is not well defined. Here, we determine the signals guiding the transition of human NMP-like cells toward thoracic ventral spinal cord neurectoderm. We show that combined WNT-FGF activities drive a posterior dorsal pre-/early neural state, whereas suppression of TGFβ-BMP signalling pathways promotes a ventral identity and neural commitment. Based on these results, we define an optimised protocol for the generation of thoracic MNs that can efficiently integrate within the neural tube of chick embryos. We expect that our findings will facilitate the comparison of hPSC-derived spinal cord cells of distinct axial identities.

Wind M ，Gogolou A ，Manipur I ，Granata I ，Butler L ，Andrews PW ，Barbaric I ，Ning K ，Guarracino MR ，Placzek M ，Tsakiridis A ... -  《-》

Dynamic extrinsic pacing of the HOX clock in human axial progenitors controls motor neuron subtype specification.

Rostro-caudal patterning of vertebrates depends on the temporally progressive activation of HOX genes within axial stem cells that fuel axial embryo elongation. Whether the pace of sequential activation of HOX genes, the 'HOX clock', is controlled by intrinsic chromatin-based timing mechanisms or by temporal changes in extrinsic cues remains unclear. Here, we studied HOX clock pacing in human pluripotent stem cell-derived axial progenitors differentiating into diverse spinal cord motor neuron subtypes. We show that the progressive activation of caudal HOX genes is controlled by a dynamic increase in FGF signaling. Blocking the FGF pathway stalled induction of HOX genes, while a precocious increase of FGF, alone or with GDF11 ligand, accelerated the HOX clock. Cells differentiated under accelerated HOX induction generated appropriate posterior motor neuron subtypes found along the human embryonic spinal cord. The pacing of the HOX clock is thus dynamically regulated by exposure to secreted cues. Its manipulation by extrinsic factors provides synchronized access to multiple human neuronal subtypes of distinct rostro-caudal identities for basic and translational applications.This article has an associated 'The people behind the papers' interview.

Mouilleau V ，Vaslin C ，Robert R ，Gribaudo S ，Nicolas N ，Jarrige M ，Terray A ，Lesueur L ，Mathis MW ，Croft G ，Daynac M ，Rouiller-Fabre V ，Wichterle H ，Ribes V ，Martinat C ，Nedelec S ... -  《-》

In vitro generation of neuromesodermal progenitors reveals distinct roles for wnt signalling in the specification of spinal cord and paraxial mesoderm identity.

Gouti M ，Tsakiridis A ，Wymeersch FJ ，Huang Y ，Kleinjung J ，Wilson V ，Briscoe J ... -  《-》

Notch signalling influences cell fate decisions and HOX gene induction in axial progenitors.

Cooper F ，Souilhol C ，Haston S ，Gray S ，Boswell K ，Gogolou A ，Frith TJR ，Stavish D ，James BM ，Bose D ，Kim Dale J ，Tsakiridis A ... -  《-》