HypoSUMOylation in embryonic stem cells generates head-and-trunk embryo-like structure [Methyl-seq]

Recent advances in synthetic mammalian embryo models have opened new avenues to understand the complex events controlling lineage decisions and morphogenetic processes occurring during peri-implantation and early organogenesis. Two main strategies have been developed to build embryo-like structures (ELS): by assembling extraembryonic and embryonic stem cells (ESCs) or by subjecting ESCs to various morphogens. Here, we show that mouse ESCs solely exposed to chemical inhibition of SUMOylation, a posttranslational modification which acts as a general barrier to cell-fate transitions, generates early ELSs comprising both anterior neural and trunk-associated regions. HypoSUMOylated ESCs give rise to adherent spheroids which, once in suspension, self-organize into gastrulating structures containing cell types spatially and functionally related to embryonic and extraembryonic compartments. Alternatively, spheroids cultured in an optimized droplet-microfluidic device form elongated structures characterized by a multi-axial organization reminiscent of natural embryo morphogenesis. Single-cell RNA-sequencing further revealed a variety of cellular lineages including properly positioned anterior neuronal cell types, Schwann cell precursors and paraxial mesoderm segmented into somite-like structures. Mechanistically, transient SUMOylation suppression gradually increases DNA methylation genome-wide and repressive marks deposition at Nanog, enhancing ESC plasticity. Our approach provides a proof of principle for a potential new strategy to study early embryogenesis by targeting reprogramming roadblocks to shape multicellular architecture. Examination of the level of methylation in ES cells treated or not with the SUMO inhibitor, in triplicate, using Illumina Illumina Hiseq 4000.