Fate and State Transitions during Human Blood Vessel Organoid Development

Human blood vessel organoids (hBVOs) have emerged as a system to model human vascular development and disease. Here, we use single-cell multi-omics together with genetic and signaling pathway perturbations to reconstruct hBVO development. Mesodermal progenitors bifurcate into endothelial and mural fates in vitro, and xenografted BVOs acquire definitive arterio-venous endothelial cell specification. We infer a gene regulatory network and use single-cell genetic perturbations to identify transcription factors (TFs) and receptors involved in cell fate specification, including a role for MECOM in endothelial and mural specification. We assess the potential of BVOs to generate organotypic states, identify TFs lacking expression in hBVOs, and find that induced LEF1 overexpression increases brain vasculature-specificity. Finally, we map vascular disease-associated genes to hBVO cell states, and analyze an hBVO model of diabetes. Altogether, we provide a comprehensive cell state atlas of hBVO development and illuminate the power and limitation of hBVOs for translational research.

人类血管类器官（human blood vessel organoids, hBVOs）现已成为模拟人类血管发育与疾病的研究体系。本研究整合单细胞多组学技术与遗传、信号通路扰动手段，重构人类血管类器官的发育进程。体外实验中，中胚层祖细胞可分化为内皮细胞与壁细胞两种细胞命运；而经异种移植的血管类器官则获得明确的动静脉内皮细胞特化表型。我们通过构建基因调控网络，并结合单细胞遗传扰动实验，鉴定出参与细胞命运特化的转录因子（transcription factors, TFs）与受体蛋白，其中MECOM在内皮细胞与壁细胞特化过程中发挥调控作用。我们评估了血管类器官形成器官特异性细胞状态的潜能，筛选出在人类血管类器官中未表达的转录因子，并发现诱导LEF1过表达可提升其脑血管特异性。最后，我们将血管疾病相关基因映射至人类血管类器官的细胞状态中，并分析了糖尿病相关的人类血管类器官模型。综上，本研究构建了人类血管类器官发育的完整细胞状态图谱，并阐明了人类血管类器官在转化研究中的应用价值与局限性。