The role of YAP1 in angiogenesis during organ regeneration

项目总结： 血管生成--新的毛细血管的形成--在器官再生中起着关键作用。因此，为了 对于成人器官的再生，我们需要了解器官再生过程中血管生成的机制。它 有报道称，成人肺在单侧肺切除术(PNX)后有生长的潜力。 抑制血管生成会损害PNX治疗后成年小鼠的肺生长。这项提案的总体目标是 以肺为模型和杠杆研究器官再生过程中血管生成的机制 这一知识有助于开发一种有效的器官再生策略。机械敏感型转录辅基 激活物，是相关蛋白(YAP1)和带有PDZ结合基序的转录共激活物(TAZ)， 刺激血管生成，控制器官大小和再生。在肺中，YAP1在肺泡干中的激活 细胞促进PNX后的肺生长。然而，内皮细胞YAP1/TAZ在血管生成中的作用 PNX的肺生长情况仍不清楚。我们的初步数据表明，YAP1和/或TAZ的敲除 减少血管生成因子受体Tie2在血管内皮细胞的表达并抑制内皮细胞 发芽了。单侧PNX后，YAP1/TAZ和Tie2表达增加，血管密度增加。 剩下的肺叶。VE-钙粘蛋白特异性YAP1和/或PNX后代偿性肺生长受抑 三苯氧胺诱导的Taz基因敲除小鼠(Yap1fl/fl-CDH5CreERT2、Yap1iΔEC、Taz IΔEC或Yap1/TaziΔEC) YAP1/Taz缺失。当我们将纤维蛋白凝胶植入对照Yap1fl/fl小鼠肺上时，内皮细胞从 宿主肺，并在植入的凝胶中形成血管网络，而血管形成在 将凝胶植入Yap1fl/fl-CDH5CreERT2小鼠肺内。实质拉伸和微血管增多 单侧PNX术后的灌流和剪切力有助于PNX术后肺的生长。硅胶植入 用假体替换切除的肺叶可阻止PNX术后肺生长，并降低YAP1/TAZ的表达。 结扎右心叶肺动脉刺激剩余未闭塞肺叶的肺生长 在离开PNX之后。我们假设在PNX后的代偿性肺生长过程中会刺激血管生成。 通过机械敏感的内皮细胞YAP1/TAZ信号转导。在目标1中，我们将通过以下方式来研究其机制 在体外PNX术后肺生长过程中，哪些血管内皮细胞YAP1/TAZ控制血管生成信号。在目标2中，我们 将确定内皮细胞YAP1/TAZ是否控制PNX后肺生长过程中的血管形成 老鼠的肺。在目标3中，我们将研究PNX改变的机械环境对血液的影响 小鼠肺内血管的形成。我们对血管生成新的机械敏感机制的关注 在PNX后肺生长和新的小鼠肺凝胶植入系统是高度独特的和 创新的科学进步。如果本研究证实血管内皮细胞YAP1/TAZ刺激血管生成 小鼠肺经过PNX后，这项工作将进一步加深我们对血管生成机制的理解，并导致 开发新的和更好的器官再生策略。

Project Summary: Angiogenesis – the formation of new blood capillaries - plays a key role in organ regeneration. Thus, in order to regenerate adult organs, we need to understand the mechanisms of angiogenesis during organ regeneration. It has been reported that adult human lungs have potential to grow after unilateral pneumonectomy (PNX) and that inhibition of angiogenesis impairs post-PNX lung growth in adult mice. The overall goal of this proposal is to characterize the mechanism of angiogenesis during organ regeneration using lung as a model and leverage this knowledge to develop an efficient strategy for organ regeneration. Mechanosensitive transcriptional co- activators, Yes-associated protein (YAP1) and transcriptional co-activator with PDZ-binding motif (TAZ), stimulate angiogenesis and control organ size and regeneration. In the lung, YAP1 activation in alveolar stem cells promotes post-PNX lung growth. However, the role of endothelial YAP1/TAZ in angiogenesis during post- PNX lung growth remains unclear. Our preliminary data demonstrate that knockdown of YAP1 and/or TAZ decreases the expression of angiogenic factor receptor, Tie2, in endothelial cells (ECs) and inhibits EC sprouting. After unilateral PNX, the expression of YAP1/TAZ and Tie2 and vascular density increased in the remaining lung lobes. Compensatory lung growth after PNX was inhibited in VE-cadherin-specific Yap1 and/or Taz knockout (Yap1fl/fl-Cdh5CreERT2, Yap1iΔEC, Taz iΔEC, or Yap1/TaziΔEC) mice after tamoxifen-induced Yap1/Taz deletion. When we implanted fibrin gel on the control Yap1fl/fl mouse lung, ECs were recruited from host lungs and made vascular networks in the implanted gels, while vascular formation was attenuated in the gel implanted on the Yap1fl/fl-Cdh5CreERT2 mouse lungs. Parenchymal stretch and increases in microvascular perfusion and shear stress after unilateral PNX contribute to post-PNX lung growth. Insertion of silicone prosthesis to replace an excised lobe prevented post-PNX lung growth and decreased YAP1/TAZ expression. Ligation of right cardiac lobe pulmonary artery stimulated lung growth of the remaining non-occluded lobes after left PNX. We hypothesize that angiogenesis is stimulated during compensatory lung growth after PNX through mechanosensitive endothelial YAP1/TAZ signaling. In Aim 1, we will investigate the mechanism by which endothelial YAP1/TAZ control angiogenic signaling during post-PNX lung growth in vitro. In Aim 2, we will determine whether endothelial YAP1/TAZ control blood vessel formation during post-PNX lung growth in the mouse lung. In Aim 3, we will investigate the effects of mechanical environment altered by PNX on blood vessel formation in the mouse lung. Our focus on the new mechanosensitive mechanism of angiogenesis during post-PNX lung growth and the novel mouse lung gel implantation system are highly unique and innovative scientific advances. If this study validates that endothelial YAP1/TAZ stimulate angiogenesis in the mouse lungs after PNX, this work will further our understanding of the mechanism of angiogenesis and lead to the development of new and better strategies for organ regeneration.