Yao Ikuko, Sugiura Yuki, Matsumoto Mineo, Setou Mitsutoshi
Mitsubishi Kagaku Institute of Life Sciences (MITILS), Machida, Tokyo, Japan.
Proteomics. 2008 Sep;8(18):3692-701. doi: 10.1002/pmic.200701121.
Imaging MS is emerging as a useful tool for proteomic analysis. We utilized this technique to analyze gene knockout (KO) mice in addition to traditional 2-DE analysis. The Scrapper-knockout (SCR-KO) mouse brain showed two types of neurodegenerative pathologies, the spongiform neurodegeneration and shrinkage of neuronal cells. 2-DE analysis of the whole brain lysates of SCR-KO mice indicated slight changes in annexin A6, Rap1 GTPase, and glyoxalase domain containing four spots while most of the main components did not show significant changes. By imaging MS analysis based on principal component analysis (PCA), we could find numerous alterations in the KO mouse brain. Furthermore, we could also know the information on the position of altered substances all together. PCA provides information about which molecules in tissue microdomains have altered and is helpful in analyzing large dataset of imaging MS, while exact identification of each molecule from peaks in MALDI imaging MS may require additional analyses such as MS/MS. Direct imaging with PCA is a powerful tool to perform in situ proteomics and will lead to novel findings. Our study shows that imaging MS yields information complementary to conventional 2-DE analysis.
成像质谱正逐渐成为蛋白质组学分析的一种有用工具。除了传统的二维电泳（2-DE）分析外，我们还利用这项技术对基因敲除（KO）小鼠进行分析。Scrapper基因敲除（SCR-KO）小鼠的大脑表现出两种神经退行性病变，即海绵状神经变性和神经元细胞萎缩。对SCR-KO小鼠全脑裂解物进行的二维电泳分析表明，膜联蛋白A6、Rap1 GTP酶和含乙二醛酶结构域的四个斑点有轻微变化，而大多数主要成分没有显著变化。通过基于主成分分析（PCA）的成像质谱分析，我们在基因敲除小鼠的大脑中发现了许多改变。此外，我们还能同时了解到发生改变的物质的位置信息。主成分分析提供了关于组织微区中哪些分子发生改变的信息，有助于分析成像质谱的大型数据集，而从基质辅助激光解吸电离成像质谱（MALDI成像质谱）的峰中准确鉴定每个分子可能需要额外的分析，如串联质谱（MS/MS）。用主成分分析进行直接成像，是开展原位蛋白质组学研究的有力工具，将带来新的发现。我们的研究表明，成像质谱产生的信息与传统二维电泳分析互补。
