High-Resolution Secondary Ion Mass Spectrometry for Chemically Imaging Cell Membrane Organization

在化学系(CHE)的化学测量和成像计划(CMI)以及分子和细胞生物科学系(MCB)的细胞动力学和功能簇的支持下，伊利诺伊大学厄巴纳-香槟分校的Mary Kraft教授和她的团队正在开发新的方法来定量成像不同脂类的亚细胞分布。不同细胞器细胞膜中胆固醇相对丰度的差异会影响哺乳动物细胞的功能，并与疾病相关。然而，目前的分析工具不足以评估亚细胞间隔内的胆固醇丰度。克拉夫特教授和她的团队计划通过开发一种高分辨率二次离子质谱仪方法来满足这一需求，以高空间分辨率对特定细胞细胞器中的胆固醇和鞘磷脂进行定量成像。这项工作需要开发和优化细胞器检测的标记策略、深度剖析条件和定量数据分析方法，以及哺乳动物细胞上溅射率的测定。拟议的研究将产生一种化学特异性的方法，用于成像特定细胞器或近细胞内感兴趣的蛋白质中胆固醇和其他脂质物种的相对丰度，横向分辨率低于100 nm。这种化学成像工具将极大地有助于确定胆固醇调节细胞内运输的机制，并最终调节细胞功能。该项目将在二次离子质谱学、细胞生物学、新陈代谢、定量生物分析化学、实验设计和假设检验方面培训研究生和本科生。结果将被纳入讲座和实验室活动，该活动将在为9年级和10年级年轻女性举办的女生数学、工程和科学冒险(游戏)生物和化学工程夏令营上公布。

With support from the Chemical Measurement and Imaging Program (CMI) in the Division of Chemistry (CHE) and the Cellular Dynamics and Function Cluster in the Division of Molecular and Cellular Biosciences (MCB), Professor Mary Kraft and her group at University of Illinois at Urbana-Champaign are developing new approaches to quantitatively image the subcellular distribution of distinct lipid species. Differences in the relative abundances of cholesterol among the membranes of various organelles influence mammalian cell function and are correlated with disease. Yet, current analytical tools are inadequate for assessing the cholesterol abundance within subcellular compartments. Professor Kraft and her team plan to address this need by developing a high-resolution secondary ion mass spectrometry method for quantitatively imaging cholesterol and sphingolipids within specific cellular organelles with high spatial resolution. This work entails the development and optimization of labeling strategies for organelle detection, depth profiling conditions, and quantitative data analysis methods, as well as determination of sputtering rates on mammalian cells.The proposed research will yield a chemically specific approach for imaging the relative abundances of cholesterol and other lipid species in specific organelles or near intracellular proteins of interest with less than 100-nm-lateral resolution. This chemical imaging tool will greatly facilitate identifying the mechanisms by which cholesterol regulates intracellular trafficking, and ultimately, cellular function. The project will train graduate and undergraduate students in secondary ion mass spectrometry, cell biology, metabolism, quantitative bioanalytical chemistry, experimental design and hypothesis testing. Results will be incorporated into a lecture and laboratory activity that will be presented at the Girls' Adventures in Mathematics, Engineering, and Science (GAMES) Bio- and Chemical Engineering Camp for 9th and 10th grade young women.