Endothelial cells adopt tissue-specific characteristics to instruct organ development and regeneration 1 , 2 . This adaptability is lost in cultured adult endothelial cells, which do not vascularize tissues in an organotypic manner. Here, we show that transient reactivation of the embryonic-restricted ETS variant transcription factor 2 (ETV2) 3 in mature human endothelial cells cultured in a serum-free three-dimensional matrix composed of a mixture of laminin, entactin and type-IV collagen (LEC matrix) ‘resets’ these endothelial cells to adaptable, vasculogenic cells, which form perfusable and plastic vascular plexi. Through chromatin remodelling, ETV2 induces tubulogenic pathways, including the activation of RAP1, which promotes the formation of durable lumens 4 , 5 . In three-dimensional matrices—which do not have the constraints of bioprinted scaffolds—the ‘reset’ vascular endothelial cells (R-VECs) self-assemble into stable, multilayered and branching vascular networks within scalable microfluidic chambers, which are capable of transporting human blood. In vivo, R-VECs implanted subcutaneously in mice self-organize into durable pericyte-coated vessels that functionally anastomose to the host circulation and exhibit long-lasting patterning, with no evidence of malformations or angiomas. R-VECs directly interact with cells within three-dimensional co-cultured organoids, removing the need for the restrictive synthetic semipermeable membranes that are required for organ-on-chip systems, therefore providing a physiological platform for vascularization, which we call ‘Organ-On-VascularNet’. R-VECs enable perfusion of glucose-responsive insulin-secreting human pancreatic islets, vascularize decellularized rat intestines and arborize healthy or cancerous human colon organoids. Using single-cell RNA sequencing and epigenetic profiling, we demonstrate that R-VECs establish an adaptive vascular niche that differentially adjusts and conforms to organoids and tumoroids in a tissue-specific manner. Our Organ-On-VascularNet model will permit metabolic, immunological and physiochemical studies and screens to decipher the crosstalk between organotypic endothelial cells and parenchymal cells for identification of determinants of endothelial cell heterogeneity, and could lead to advances in therapeutic organ repair and tumour targeting. The transient reactivation of ETV2 in adult human endothelial cells reprograms these cells to become adaptable vasculogenic endothelia that in three-dimensional matrices self-assemble into vascular networks that can transport blood and physiologically arborize organoids and decellularized tissues.

中文翻译：

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用于器官发生和肿瘤发生的适应性血流动力学内皮细胞

内皮细胞采用组织特异性特征来指导器官发育和再生 1、2。这种适应性在培养的成人内皮细胞中丧失，它们不会以器官型方式使组织血管化。在这里，我们展示了胚胎限制性 ETS 变异转录因子 2 (ETV2) 3 在成熟人内皮细胞中的瞬时重新激活，该细胞培养在由层粘连蛋白、致动蛋白和 IV 型胶原混合物组成的无血清三维基质中。 LEC 基质）将这些内皮细胞“重置”为适应性强的血管生成细胞，这些细胞形成可灌注和可塑性的血管丛。通过染色质重塑，ETV2 诱导成管形成途径，包括 RAP1 的激活，从而促进持久管腔 4 、 5 的形成。在不受生物打印支架限制的三维矩阵中，“重置”血管内皮细胞 (R-VEC) 在可扩展的微流体室内自组装成稳定、多层和分支的血管网络，能够运输人体血液。在体内，植入小鼠皮下的 R-VECs 自组织成耐用的周细胞涂层血管，这些血管在功能上与宿主循环吻合并表现出持久的图案，没有畸形或血管瘤的证据。R-VECs 直接与三维共培养类器官内的细胞相互作用，消除了对器官芯片系统所需的限制性合成半透膜的需求，因此为血管形成提供了一个生理平台，我们称之为“器官”。血管网”。R-VECs 能够灌注葡萄糖反应性胰岛素分泌的人胰岛，使脱细胞大鼠肠道血管化，并使健康或癌变的人结肠类器官形成树枝状结构。使用单细胞 RNA 测序和表观遗传分析，我们证明 R-VECs 建立了一个适应性血管生态位，以组织特异性方式差异调整和符合类器官和类肿瘤。我们的 Organ-On-VascularNet 模型将允许进行代谢、免疫学和物理化学研究和筛选，以破译器官型内皮细胞和实质细胞之间的串扰，以确定内皮细胞异质性的决定因素，并可能导致治疗性器官修复和肿瘤靶向的进展。