低强度连续超声激活SIRT1调控HIF-1α/VEGF信号通路在小鼠缺血下肢血管新生中的作用与机制

Ischemic diseases threat human’s health seriously. Low-intensity continuous ultrasound has been shown to promote angiogenesis in many ischemic diseases, but the exact mechanisms remain to be elucidated. Our prior studies have demonstrated that low-intensity continuous ultrasound can promote angiogenesis through up-regulation VEGF and HIF-1αin ischemic hind li mb of mice. Meanwhile, the expression of SIRT1 was increased. Therefore, our hypothesis is that low-intensity continuous ultrasound promotes angiogenesis in ischemic hind limb of mice through up-regulating HIF-1α/VEGF signaling pathway in a SIRT1-dependent fashion. In this proposal, we will study on HIF-1α/VEGF signaling pathway using an SIRT1 gene knockout model in HUVECs and ischemic hind limb mouse. We will observe the expression of angiogenesis related factors involved in HIF-1α/VEGF signaling pathways when SIRT1 and HIF-1α activity were intervened at the cellular and animal level. And then the possible regulatory mechanisms by which low-intensity continuous ultrasound promotes angiogenesis will be elucidated. More importantly, those results might provide novel theory basis and therapeutic targets for prevention and cure of ischemic diseases.

缺血性疾病严重威胁人类健康，低强度连续超声波具有促进血管新生，治疗缺血性疾病的作用，但具体机制未明。本课题组前期研究发现，低强度连续超声波能促进小鼠缺血下肢血管新生，且显著上调沉默信息调节因子-1(SIRT-1)的表达，同时发现HIF-1α和VEGF表达水平增加，提示低强度连续超声波促进小鼠缺血下肢血管新生可能与SIRT1上调继而影响HIF-1α/VEGF信号通路有关。本研究拟围绕HIF-1α/VEGF信号通路相关因子，构建人脐静脉内皮细胞乏氧模型和小鼠缺血下肢动物模型，运用基因敲除、RNA干扰等技术，在细胞和动物的水平利用低强度连续超声波干预SIRT1活性，观察HIF-1α/VEGF信号通路相关因子的表达，明确低强度连续超声波促进小鼠缺血下肢血管新生可能的分子机制, 为缺血性疾病的防治提供新的理论依据和治疗靶点。

本课题通过构建人脐静脉内皮细胞（HUVECs）乏氧模型和小鼠缺血下肢动物模型，运用基因敲除、RNA干扰等技术，在细胞和动物的水平利用低强度连续超声波干预SIRT1活性，观察HIF-1α/VEGF信号通路相关因子的表达。.研究结果表明：.1.体外证实低强度连续TUS通过激活SIRT1调控HIF-1α/VEGF促进HUVECs血管样结构形成，并促进HIF-1α、VEGF、Ang-1等促血管生成因子mRNA以及蛋白的表达，发挥促血管生成作用。.2.体外给予HIF-1α激活剂（DFO）或抑制剂（YC-1），反向研究证实低强度连续TUS激活SIRT1促进HUVECs血管样结构形成，TUS通过激活SIRT1调控HIF-1α/VEGF信号通路发挥促血管生成效应。.3.体内研究低强度连续TUS通过激活SIRT1促进HIF-1α/VEGF信号通路，促进小鼠缺血下肢血管新生。.4.本项目构建Sirt1-/- 和Hif-1α-/-HUVECs乏氧细胞模型及其制备方法，为我们后续进行缺氧相关研究提供了有效的细胞模型工具。.5.本研究采用的治疗性超声波的物理参数及其干预条件，为后续进行相关研究积累了一定的经验。.本项目研究成果初步明确了低强度连续超声波促进小鼠缺血下肢血管新生可能的分子机制, 为缺血性疾病的防治提供了新的理论依据和治疗靶点。已发表SCI论文2篇，协助培养博士研究生2人。