Identification and tracking of neural stem cells in vivo: a metabolomic approach

描述(由申请人提供)：通过脑成像识别人类神经干细胞(NSC)的能力可能对诊断、预后和治疗目的具有深远的影响。目前，还没有临床的高分辨率成像技术能够研究未标记的神经干细胞及其后代的存活、迁移、命运和功能。由于缺乏明确的标记来区分人类神经干细胞与其他类型的神经细胞，阻碍了体内对人类神经干细胞的研究。本研究的目的是通过研究神经干细胞在体外和体内的代谢指纹图谱来确定神经干细胞的标志物。我们的目标是开发新的成像和信号处理方法，以实现对从人类早期发育到老年的健康和疾病状态下的NSC行为的非侵入性研究。我们假设哺乳动物的神经干细胞有一个特定的代谢标记物，可以用光谱学来鉴定。我们的具体目标是：1)使用质子核磁共振(1H-NMR)波谱表征体外NSC的代谢指纹，并将其与神经元和神经胶质的1H-核磁共振指纹进行比较；2)开发高分辨率质子磁共振波谱(1H-MRS)采集协议，从而能够表征NSC在体内的命运；3)开发信号处理算法，即使在低信噪比和有限的光谱、空间和时间分辨率的数据中也能提供准确的细胞密度估计。我们的初步实验表明，我们能够根据NSC的1H-核磁共振代谢指纹图谱来识别NSC。此外，使用1H-MRS和9.4T mMRI扫描仪，我们可以在活体大鼠脑中检测到内源性和外源性NSC。我们计划进一步描述神经干细胞和其他类型神经细胞的代谢特征，并进一步对活着的大鼠大脑进行代谢组学分析。用于体内神经干细胞识别、定量和跟踪的信号处理算法将基于奇异值分解方法，并将利用从体外实验中获得的先验知识。这一创新研究不仅将证明利用1H-MRS波谱进行体内代谢组学研究的可行性，而且还将导致干细胞研究领域的突破。最重要的是，这项研究是未来NSC临床研究的必要前提。监测人类大脑中神经干细胞的根本性变化的能力将引发对神经功能障碍的新研究，其中神经干细胞的病理可能有助于疾病的病因，并将启动新的治疗方法的开发。拟议的研究本质上是多学科的，涉及神经科学家、物理学家、工程师、化学家和成像科学家的合作。他们中的每一个都将提供石溪大学和布鲁克海文国家实验室可用的独特而互补的专业知识和资源。

DESCRIPTION (provided by applicant): The ability to identify human neural stem cells (NSC) by brain imaging may have profound implications for diagnostic, prognostic, and therapeutic purposes. Currently, there are no clinical, high-resolution imaging techniques that enable investigations of the survival, migration, fate, and function of unlabeled NSC and their progeny. The study of human NSC in vivo is hindered by the absence of well-defined markers that can distinguish them from other neural cell types. The goal of this proposal is to define markers of NSC by characterizing metabolomic fingerprint of NSC both in vitro and in vivo. Our objectives are to develop novel imaging and signal processing methodologies that would enable non-invasive investigations of NSC behavior in healthy and disease states, from early human development to older age. We hypothesize that mammalian NSC have a specific metabolic marker that can be identified by spectroscopy. Our specific aims are: 1) to characterize a metabolomic fingerprint of NSC in vitro using proton nuclear magnetic resonance (1H-NMR) spectroscopy and to compare it to the neuronal and glial 1H-NMR fingerprints; 2) to develop high resolution proton MR spectroscopy (1H-MRS) acquisition protocols that will allow for characterization of the NSC fate in vivo; 3) to develop signal processing algorithms that will provide accurate estimates of cell densities even from data with low signal-to-noise ratio and limited spectral, spatial, and temporal resolutions. Our preliminary experiments have demonstrated that we are able to identify the NSC on the basis of their 1H-NMR metabolomic fingerprint. In addition, we can detect both endogenous and exogenous NSC in the living rat brain, using 1H-MRS and 9.4T mMRI scanner. We plan to further characterize the metabolomic signature of NSC and other neural cell types, and to further perform metabolomic profiling of the living rat brain. The signal processing algorithms for identification, quantification, and tracking of NSC in vivo will be based on singular value decomposition methodology and will exploit prior knowledge gained from in vitro experiments. This innovative research will not only demonstrate the feasibility of using 1H-MRS spectroscopy for metabolomic investigations in vivo, but will also lead to a breakthrough in the field of stem cell research. Most importantly, this research is an essential prerequisite for future clinical investigations of NSC. The ability to monitor the fundamental changes of the NSC in the human brain will instigate new studies of neurological disorders where NSC pathology might contribute to the etiology of the disease and will initiate developments of new treatments. The proposed research is intrinsically multidisciplinary and involves collaborations of neuroscientists, physicists, engineers, chemists, and imaging scientists. Each of them will provide unique yet complementary expertise and resources available at the Stony Brook University and Brookhaven National Laboratory.