Mass spectrometric imaging of molecular distributions in the brain

描述（由申请人提供）：斑胸草雀是一种鸣禽，是研究神经发生、神经回路发育以及学习和记忆的重要模型。雄性斑胸草雀在幼年发育的关键时期学习唱歌。这种发展是在解剖学上谨慎的“歌曲核”的控制下。分子遗传学和细胞培养实验表明，各种脂质和神经类固醇在雄性鸣唱回路的形成中起着关键作用。研究脂质的能力受到复杂组织制备、化学标记和分析物预选的限制。飞行时间二次离子质谱（ToF-SIMS）是一种新兴的分析复杂生物样品的技术，它克服了这些障碍。该技术已经成功地检测和成像小鼠脑切片和肌肉组织中的各种脂质和其他小分子，而我们的合作者已经成像了维生素E在分离的单个神经元中的分布。我们发表的研究结果首次表明，在斑胸草雀的学习和记忆中必不可少的两个歌曲核中的各种脂肪酸的定位。初步结果表明，在已知的歌曲学习和记忆的重要区域中，脂质的存在和相对浓度的变化取决于斑胸草雀的年龄，少年（歌曲学习）或成年（歌曲结晶）。未来的研究将包括：1）通过ToF-SIMS收集不同年龄鸟类的质谱数据，并采用统计学方法来观察脂质和其他小分子浓度的相对变化; 2）验证雌激素有助于在雄性化过程中将小分子定位于歌唱核HVC-RA的假设; 3）利用ToF-SIMS技术对斑胸草雀脑内神经甾体及其前体物质的空间定位进行检测和成像，生成“神经甾体地图”。公共卫生相关性：检测和成像脂质和其他小分子的空间定位的能力将显著影响阿尔茨海默氏症和帕金森氏症等神经退行性疾病的研究。此外，它将增强我们对学习和记忆领域发展关键时期亚细胞变化的理解。最后，检测和成像类固醇的潜力将为神经生物学以及内分泌学和细胞信号传导的更大领域打开新的大门。

DESCRIPTION (provided by applicant): The zebra finch, a songbird, is an important model for studying neurogenesis, neural circuit development, and learning and memory. The male zebra finch learns to sing during a critical period in juvenile development. This development is under the control of anatomically discreet "song nuclei". Molecular genetics and cell culture experiments have suggested that various lipids and neurosteroids play a key role in song circuit formation in males. The ability to study lipids has been has been limited by complex tissue preparations, chemical labeling, and analyte pre-selection. Time-of-flight secondary ion mass spectrometry (ToF-SIMS), an emerging technology in the analysis of complex biological samples, has overcome these hurdles. The technology has been successful in detecting and imaging various lipids and other small molecules in a mouse brain section and in muscle tissue while our collaborators have imaged the distribution of vitamin E in isolated single neurons. Our published results have shown for the first time the localization of various fatty acids in two song nuclei that are essential for learning and memory in the zebra finch. Preliminary results suggest changes in the presence and relative concentration of lipids, in regions known to be important in song learning and memory, are dependent on the zebra finch age, juvenile (song learning) or adult (song crystallization). Future studies will consist of: 1) collecting mass spectral data by ToF-SIMS from different aged birds and employing statistical methods to look at relative changes in concentration of lipids and other small molecules; 2) test the hypothesis that estrogen aids in localizing small molecules to the song nuclei HVC-RA during masculinization; 3) detect and image the spatial localization of neurosteroids and their precursors in the zebra finch brain by ToF-SIMS to generate a "neruosteroid map". PUBLIC HEALTH RELEVANCE: The ability to detect and image the spatial localizationof lipids and other small molecules would significantly impact the study of such neurodegenerative diseases as Alzheimer's and Parkinson's. In addition, it would enhance our understanding of subcellular changes during the critical period of development in areas involved in learning and memory. Finally, the potential to detect and image steroids would open new doors in neurobiology and the larger fields of endocrinology and cell signaling.