Mouse embryonic stem cells self-organize into trunk-like structures with neural tube and somites

Abstract

Post-implantation embryogenesis is a highly dynamic process comprising multiple lineage decisions and morphogenetic changes that are inaccessible to deep analysis in vivo. We found that pluripotent mouse embryonic stem cells (mESCs) form aggregates that upon embedding in an extracellular matrix compound induce the formation of highly organized “trunk-like structures” (TLSs) comprising the neural tube and somites. Comparative single-cell RNA sequencing analysis confirmed that this process is highly analogous to mouse development and follows the same stepwise gene-regulatory program. Tbx6 knockout TLSs developed additional neural tubes mirroring the embryonic mutant phenotype, and chemical modulation could induce excess somite formation. TLSs thus reveal an advanced level of self-organization and provide a powerful platform for investigating post-implantation embryogenesis in a dish.

Tissue tectonics and the multi-scale regulation of developmental timing

“…Some striking examples include, but are in no way limited to, the ability of halved sea urchin embryos to each give rise to a fully formed individual, the ability of the chicken embryo to develop normally after surgical removal of a large portion of the primitive streak, and the formation of monozygotic twins [82,83]. This regulative (or self-organizing) ability of developmental systems fascinates experimental embryologists to this day and has recently come back into focus through observations regarding the ability of embryonic cells to break symmetry and generate patterns when aggregated and cultured as multi-cellular aggregates [84][85][86][87].…”

In vitro systems: A new window to the segmentation clock

“…Despite their astonishing complexity, the protocol for gastruloid generation from PSCs is remarkably simple. 3D aggregates are exposed to a pulse of the Wnt agonist CHIR99021 and then allowed to develop without additional exogenous signals (Beccari et al, 2018;Brink et al, 2014;Turner et al, 2017;Veenvliet et al, 2020). Gastruloids contain paraxial mesoderm cells and oscillations of the segmentation clock have been observed using Lfng-Venus mouse ESCs .…”

“…In conventional gastruloids, morphogenetic events such as somite formation do not take place (Beccari et al, 2018). However, recent studies have revealed that embedding gastruloids in lowpercentage Matrigel can induce morphogenesis Veenvliet et al, 2020). Under such conditions, one study reported the sequential formation of morphological somites with proper anterior-posterior polarity (i.e., Uncx4.1 and Tbx18 domains) .…”

“…Under such conditions, one study reported the sequential formation of morphological somites with proper anterior-posterior polarity (i.e., Uncx4.1 and Tbx18 domains) . Similarly, a second study described the generation of trunk-like-structures composed of a neural tube with adjacent paraxial mesoderm cells that also segmented into morphological somites (Veenvliet et al, 2020). The exact role of Matrigel in promoting such complex morphogenesis in gastruloids has not been elucidated, but these conditions certainly result in the closest approximation to an embryonic axis that has been created in vitro.…”

Biophysics of Nervous Embryo-Fetal Development

“…Development of multicellular living beings involves morphogenetic processes shaping embryo-fetal structures through self-organized activities of pluripotent stem cells (Veenvliet et al, 2020). The orchestrated movement of cellular groups involves genetic as well as mechanical and molecular interactions between cells and their environment (Thompson 1992; Barriga et al, 2018).…”