Understanding the vascular physiology after exposure to ultrasound stimulated microbubble oscillations

预血管治疗是一种很有前途的使乏氧肿瘤对放射治疗敏感的方法，但由于难以使用全身方法靶向肿瘤血管而受到阻碍。有趣的是，最近显示超声刺激的微泡（MB）振荡可以局部增加血液灌注。研究者（Yu博士）和其他人已经确定了两种新的信号通路（一氧化氮和嘌呤能信号通路）与这种血管活性反应有关，但导致其激活的条件，反应的时间过程和涉及的细胞在很大程度上是未知的。尽管之前已经研究了微泡和生物膜之间的物理相互作用，但MB与细胞相互作用后的生物反应，包括血管活性分子信号传导途径的激活，仍然未被探索。在这项研究计划中，我（余博士）将研究一氧化氮和嘌呤信号，他们的时间过程，水库和相互作用，在细胞和血管水平暴露于微泡和超声。更确切地说，我将系统地研究超声刺激MB振荡对红细胞和内皮细胞的影响，这两种细胞类型最有可能与MB相互作用，并且已知参与一氧化氮和嘌呤能调节。该研究计划由两个目标组成：在目标#1中，我们使用基本的体外细胞培养进行高通量成像实验，以研究细胞通路激活及其时间过程;在目标#2中，我们使用离体动脉血管灌注室实验来评估存在血流时的功能反应。研究了超声脉冲长度、压力以及微泡浓度对超声降解的影响。了解微泡介导的血管舒张的基本分子机制及其时间过程，将指导靶向血管放射增敏治疗癌症的发展，并从生物学和生理学角度进一步了解微泡细胞相互作用。

Provascular therapy, a promising approach to sensitize hypoxic tumor to radiotherapy, is hampered by the difficulty to target tumor vasculature using systemic approaches. Interestingly, it was recently shown that ultrasound stimulated microbubble (MB) oscillations can locally increase blood perfusion. Two new signaling pathways (nitric oxide and purinergic signaling) have been identified by the investigator (Dr Yu) and others to be implicated in this vasoactive response, but the conditions leading to their activation, the timecourse of the response and the cells implicated are largely unknown. Whereas the physical interactions between microbubbles and biological membranes have been studied before, the biological responses following MB interactions with cells, including the activation of vasoactive molecular signaling pathways, remain unexplored. In this research program, I (Dr Yu) will investigate nitric oxide and purinergic signaling, their time course, reservoir and interactions, at the cellular and vascular levels following exposure to microbubbles and ultrasound. More precisely, I will systematically study the effect of ultrasound stimulated MB oscillations on red blood cells and endothelial cells, the two cell types most likely to interact with MBs and that are known to participate in nitric oxide and purinergic regulation. The research program is composed of two objectives: in objective #1 we use basic in vitro cell culture for high throughput imaging experiments to investigate cellular pathway activation and their time course; in objective #2 we use ex vivo arterial vessel perfusion chambers experiments to assess the functional response in the presence of flow. The effect of ultrasound pulse length and pressure as well as microbubble concentration will be studied. Understanding the basic molecular mechanisms involved in microbubble mediated vasodilation, and their time course, will guide the development of targeted provascular radio-sensitization therapies against cancer and further our understanding of microbubble cell interactions from a biological and physiological perspective.