Determining the biochemical mechanism of microbubble-mediated vascular permeability

靶向药物输送最令人兴奋的进步之一是使用超声波和微泡作为工具，使血管渗漏，使治疗剂在体内特定部位离开循环。 微泡是一种小的（1-4 μ m）血管限制性超声造影剂，由围绕气体核的脂质壳组成。 当微泡与聚焦超声波束接触时，它们开始膨胀和收缩。 通过一些未知的生化机制，微泡的膨胀和收缩导致构成脉管系统的细胞之间的连接在短时间内破裂，可能是通过施加物理力。 我的目标是发展一个自然科学和工程研究计划的基础上，确定什么是微泡如何导致脉管系统成为泄漏的生化机制。 我的假设是，微泡的快速膨胀和压缩对脉管系统施加了物理应变，有效地拉伸了它并激活了监测和响应机械应力的蛋白质。 我和我的学员将通过设计微泡并在正常小鼠血管内用特殊设计的超声脉冲序列激活它们来研究这一点。然后，我们将研究在血管内皮细胞中激活了哪些基因网络，观察蛋白质定位和激活的变化，并逐步了解细胞信号传导如何改变血管系统对扩张和收缩微泡的反应。一旦我们理解了正常脉管系统中的这种生化机制，我们就可以将其作为一种工具，并将其应用于其他自然科学和工程领域，包括白细胞迁移，其中对施加于脉管系统的物理力所起的作用知之甚少。 这笔资金还将导致在未来5年内培训至少11名HQP，并为他们提供重要和新颖的技能（细胞生物学和超声工程），使他们成为加拿大研究领域的创新领导者。

One of the most exciting advancements in targeted drug delivery has been the use of ultrasound and microbubbles as a tool to cause blood vessels become leaky, allowing therapeutics to leave circulation at specific sites in the body. Microbubbles are a small (1-4 um), vascular restricted ultrasound contrast agent that consists of a lipid shell surrounding a gas core. When microbubbles come into contact with a focused ultrasound beam, they begin to expand and contract. Through some unknown biochemical mechanism, expansion and contraction of microbubbles causes the junctions in between the cells that make up the vasculature to break down for a short period of time, likely through the application of physical force. My goal is to develop a natural sciences and engineering research program based on determining what is the biochemical mechanism of how microbubbles can cause the vasculature to become leaky. It is my hypothesis that the rapid expansion and compression of microbubbles applies a physical strain to the vasculature, effectively stretching it and activating proteins that monitor and respond to mechanical stress. My trainees and I will investigate this by designing microbubbles and activating them with specially designed ultrasound pulse sequences within normal mouse vasculature. We will then investigate what gene networks are activated in the vascular endotheilal cells, observe changes in protein localization and activation, and step by step understand how cell signaling changes the vasculature response to expanding and contracting microbubbles. Once we understand this biochemical mechanism in normal vasculature, we can use it as a tool and apply it to other natural sciences and engineering fields, including leukocyte migration, where little is known about the role physical force applied to the vasculature plays. This funding will lead also result in the training of a minimum of 11 HQP within the next 5 years and provide them with an important and novel skillset (cell biology and ultrasound engineering) allowing them to become leaders of innovation within Canadian research.