ETS variant transcription factor 2 (ETV2) serves as a foundational transcription factor for endothelial lineage specification. However, the lineage-specific cofactors that orchestrate with ETV2 during endothelial fate commitment remain elusive. Here, we demonstrate that ETV2 drives the rapid forward programming of human pluripotent stem cells (hPSCs) into endothelial cells (ECs) by direct remodeling of endothelial-specific enhancers. Crucially, we identify T cell acute lymphocytic leukemia protein 1 (TAL1), which is traditionally characterized as a hematopoietic regulator, as an indispensable cofactor for ETV2-mediated endothelial commitment. Distinct from its role in murine development, TAL1 deficiency in hPSCs not only aborts the endothelial program by impairing H3K27ac deposition at key enhancers but also triggers a profound lineage redirection toward a mesenchymal fate. Mechanistically, TAL1 physically interacts with ETV2 to recruit the p300, thereby facilitating a permissive chromatin environment for endothelial identity. By leveraging an hPSC-based differentiation model, our findings establish TAL1 as a master gatekeeper of human EC specification and provide a molecular blueprint for how ETV2-centric complexes synergistically govern human cell fate.
Yun Zhao, Mengze Sun, Zixuan Hong et al.· Science Advances· 0 citations
The development of functional human vasculature is essential for tissue engineering, disease modeling, and regenerative medicine. Conventional differentiation protocols of vascular lineages often exhibit lineage heterogeneity and limited control over cellular ratios. Here, we describe a protocol for generating vascular organoids (VOs) via orthogonal forward programming of hPSCs. By utilizing doxycycline-inducible activation of the transcription factors ETV2 and NKX3.1, hPSCs are rapidly directed toward endothelial and mural cell lineages, respectively. This strategy enables the assembly of VOs with precisely tunable cellular compositions within six days. When combined with fluorescent reporter lines (PECAM1-mRuby3 and ACTA2-EGFP), vascular networks can be visualized in real time without the need for tissue clearing or immunostaining. We detail procedures for stable cell line engineering, 3D organoid assembly, in vitro angiogenesis assays for drug screening, and in vivo transplantation under the mouse kidney capsule to form perfusable human vasculature. This platform provides a flexible, standardized, and scalable tool for investigating vascular biology, modeling inherited vasculopathies, and enhancing the vascularization of co-transplant tissues.
Yun Zhao, Mengze Sun, Kun Zhang et al.· Cell Regeneration· 0 citations
