College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging in Universities of Shandong, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Institute of Biomedical Sciences, Shandong Normal University , Jinan, Shandong 250014, P.R. China.
Anal Chem. 2017 Apr 18;89(8):4642-4647. doi: 10.1021/acs.analchem.7b00221. Epub 2017 Apr 7.
High concentrations of oxidized low density lipoprotein (oxLDL) induce aberrant apoptosis of vascular smooth muscle cells (VSMCs) in atherosclerotic plaques. This apoptosis cannot be blocked completely by the inhibition of caspase, and it eventually potentiates plaque disruption and risk for cardiovascular disease. Given the important role of apoptosis inducing factor (AIF) in caspase-independent apoptosis, here we develop an AIF-targeting nanosensor by the assembly of graphene oxide (GO) nanosheets and dye-labeled DNA hybrid structures. This nanosensor selectively localizes in the cytosol of VSMCs, where it exhibits a "turn-off" fluorescence signal. Under oxLDL stimuli, the release of AIF from mitochondria into cytosol liberates the DNA hybrid structures from the surface of GO and results in a "turn-on" fluorescence signal. This nanosensor is shown to possess rapid response, high sensitivity, and selectivity for AIF that enables real-time imaging of AIF translocation in VSMCs. Using this novel nanosensor, a better assessment of the apoptotic level of VSMCs and a more accurate evaluation of the extent of atherosclerotic lesions can be obtained. More importantly, the abundant binding between DNA hybrid structures and AIF inhibits the translocation of AIF into the nucleus and subsequent apoptosis in VSMCs. This inhibition may help stabilize plaque and reduce the risk of heart attack and stroke.
高浓度的氧化型低密度脂蛋白（oxLDL）可诱导动脉粥样硬化斑块中的血管平滑肌细胞（VSMCs）发生异常凋亡。这种凋亡不能被 caspase 的抑制完全阻断，最终会增强斑块破裂和心血管疾病的风险。鉴于凋亡诱导因子（AIF）在 caspase 非依赖性凋亡中的重要作用，我们通过组装氧化石墨烯（GO）纳米片和染料标记的 DNA 杂交结构，开发了一种针对 AIF 的纳米传感器。这种纳米传感器选择性地定位于 VSMCs 的细胞质中，在那里它表现出“关闭”的荧光信号。在 oxLDL 刺激下，AIF 从线粒体释放到细胞质中，使 DNA 杂交结构从 GO 表面释放出来，导致荧光信号“开启”。该纳米传感器具有快速响应、高灵敏度和对 AIF 的选择性，可实时成像 VSMCs 中的 AIF 易位。使用这种新型纳米传感器，可以更好地评估 VSMCs 的凋亡水平，并更准确地评估动脉粥样硬化病变的程度。更重要的是，DNA 杂交结构与 AIF 之间的大量结合抑制了 AIF 向细胞核的易位和随后在 VSMCs 中的凋亡。这种抑制可能有助于稳定斑块，降低心脏病发作和中风的风险。
