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

在化学部 (CHE) 化学测量和成像计划 (CMI) 以及分子和细胞生物科学部 (MCB) 细胞动力学和功能集群的支持下，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方法，对不同脂质种类的亚细胞分布进行定量成像。各种细胞器膜之间胆固醇相对丰度的差异影响哺乳动物细胞功能并与疾病相关。然而，当前的分析工具不足以评估亚细胞室内的胆固醇丰度。 Kraft 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方法来满足这一需求，以高空间分辨率对特定细胞器内的胆固醇和鞘脂进行定量成像。 这项工作需要开发和优化用于细胞器检测的标记策略、深度分析条件和定量数据分析方法，以及确定哺乳动物细胞的溅射速率。拟议的研究将产生一种化学特异性方法，以小于 100 nm 的横向分辨率对特定细胞器或感兴趣的细胞内蛋白质附近的胆固醇和其他脂质种类的相对丰度进行成像。这种化学成像工具将极大地促进确定胆固醇调节细胞内运输并最终调节细胞功能的机制。该项目将对二次离子质谱、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的研究生和本科生进行培训。研究结果将纳入讲座和实验室活动中，并在针对 9 年级和 10 年级年轻女生的数学、工程和科学女孩历险记 (GAMES) 生物和化学工程营中展示。

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.