VEGF/ERK activation and PI3K inhibition together drive a vein-to-artery transition in an in vitro model of human angiogenesis

ABSTRACT Artery endothelial cells (ECs) arise through different pathways, including differentiation from mesodermal cells (vasculogenesis) or from already established vein or capillary plexus ECs (angiogenesis), the latter being most common during embryonic development and regeneration. Understanding the vein-to-artery (v2a) transition could improve revascularization therapies, but progress is limited by a lack of human models. Here, we develop a human pluripotent stem cell (hPSC) differentiation protocol that models the v2a EC conversion. Comparing v2a and mesoderm-to-artery (m2a) transcriptomes with publicly available single cell RNA sequencing (scRNA-seq) data from human embryos showed they reflected angiogenesis- and vasculogenesis-derived artery ECs, respectively. This reductionist system revealed that VEGF activation alongside PI3K inhibition was sufficient for vein ECs to acquire arterial identity within 48 hours. We model a critical step in vascular development and define the minimal signals required for artery differentiation from veins, providing a framework to promote this conversion in revascularization or therapeutic contexts. Competing Interest Statement Stanford University has filed patent applications related to endothelial differentiation. Footnotes This version of the manuscript has been revised to reflect the final accepted manuscript. Figures 1 through 4 have been updated in the main text, and Supplementary Figures S1 through S4 and their legends have been updated accordingly. Minor formatting and text clarifications were made to align with the final journal version.