Quantitative Biology Center, Riken, Suita, Osaka, Japan.
Department of Applied Physics, Osaka University, Suita, Osaka, Japan.
PLoS One. 2014 Jan 7;9(1):e84478. doi: 10.1371/journal.pone.0084478. eCollection 2014.
System level understanding of the cell requires detailed description of the cell state, which is often characterized by the expression levels of proteins. However, understanding the cell state requires comprehensive information of the cell, which is usually obtained from a large number of cells and their disruption. In this study, we used Raman spectroscopy, which can report changes in the cell state without introducing any label, as a non-invasive method with single cell capability. Significant differences in Raman spectra were observed at the levels of both the cytosol and nucleus in different cell-lines from mouse, indicating that Raman spectra reflect differences in the cell state. Difference in cell state was observed before and after the induction of differentiation in neuroblastoma and adipocytes, showing that Raman spectra can detect subtle changes in the cell state. Cell state transitions during embryonic stem cell (ESC) differentiation were visualized when Raman spectroscopy was coupled with principal component analysis (PCA), which showed gradual transition in the cell states during differentiation. Detailed analysis showed that the diversity between cells are large in undifferentiated ESC and in mesenchymal stem cells compared with terminally differentiated cells, implying that the cell state in stem cells stochastically fluctuates during the self-renewal process. The present study strongly indicates that Raman spectral morphology, in combination with PCA, can be used to establish cells' fingerprints, which can be useful for distinguishing and identifying different cellular states.
系统水平上对细胞的理解需要对细胞状态进行详细描述，而细胞状态通常由蛋白质的表达水平来表征。然而，理解细胞状态需要综合细胞的全面信息，这通常需要从大量细胞及其破坏中获得。在这项研究中，我们使用拉曼光谱学作为一种非侵入性的单细胞方法，该方法无需引入任何标记即可报告细胞状态的变化。在来自小鼠的不同细胞系中，细胞质和细胞核水平的拉曼光谱都观察到了显著的差异，这表明拉曼光谱反映了细胞状态的差异。在神经母细胞瘤和脂肪细胞诱导分化前后，观察到细胞状态的差异，表明拉曼光谱可以检测细胞状态的细微变化。当拉曼光谱与主成分分析（PCA）结合使用时，可以可视化胚胎干细胞（ESC）分化过程中的细胞状态转变，表明分化过程中细胞状态逐渐转变。详细分析表明，与终末分化细胞相比，未分化的 ESC 和间充质干细胞中的细胞间多样性较大，这意味着干细胞中的细胞状态在自我更新过程中随机波动。本研究强烈表明，拉曼光谱形态学与 PCA 相结合可用于建立细胞指纹图谱，这对于区分和识别不同的细胞状态可能很有用。
