Human organoids uncover PTEN-driven mesendoderm specification via inhibition of retinoic acid signaling pathways [ATAC-Seq]

ABSTRACT: Epiblast cells ingress into the primitive streak, undergoing mesendoderm (MES) specification, which subsequently gives rise to the mesoderm and endoderm. Although recent advances in human organoid technology facilitating the study of early post-implantation development, robust human models that accurately recapitulate MES specification and primitive streak (PS) formation remain lacking. Here, we showed that human induced pluripotent stem cells (iPSCs) can be employed to generate three-dimensional (3D) MES organoids that closely mimic in vivo human MES specification, particularly the cells from the anterior region of primitive streak. We revealed that formation of MES organoids depended on the appearance of PTEN, and PTEN abrogation potently impaired the MES organoids-derived definitive endoderm and mesoderm specification. To elucidate the molecular mechanisms underlying the defects induced by PTEN loss, we performed integrative multi-omic analyses‒including RNA sequencing (RNA-seq), assay for transposase-accessible chromatin using sequencing (ATAC-seq), and phospho‒proteomics‒on WT and PTEN−/− MES cells. These analyses indicated retinoic acid (RA) signalling as a critical pathway suppressed by PTEN during MES lineage specification. Moreover, we identified CYP26A1, a RA-degrading enzyme, as a key downstream effector of PTEN in MES cell generation. Notably, our results demonstrated that excessive RA was detrimental, while an optimal level of RA was indispensable for MES cell generation. Overall, our MES organoids provide a valuable platform for investigating human MES specification, and our findings demonstrated PTEN as a driver of MES lineage commitment through the inhibition of RA signalling.

ORGANISM(S): Homo sapiens

PROVIDER: GSE301161 | GEO | 2026/08/19

REPOSITORIES: GEO