Zhou Hao, Nguyen Lisa, Arnesano Cosimo, Ando Yuta, Raval Manmeet, Rodgers Joseph T, Fraser Scott, Lu Rong, Shen Keyue
Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA.
Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033, USA.
iScience. 2020 Feb 21;23(2):100831. doi: 10.1016/j.isci.2020.100831. Epub 2020 Jan 10.
Metabolism is a key regulator of hematopoietic stem cell (HSC) functions. There is a lack of real-time, non-invasive approaches to evaluate metabolism in single HSCs. Using fluorescence lifetime imaging microscopy, we developed a set of metabolic optical biomarkers (MOBs) from the auto-fluorescent properties of metabolic coenzymes NAD(P)H and FAD. The MOBs revealed the enhanced glycolysis, low oxidative metabolism, and distinct mitochondrial localization of HSCs. Importantly, the fluorescence lifetime of enzyme-bound NAD(P)H (τ) can non-invasively monitor the glycolytic/lactate dehydrogenase activity in single HSCs. As a proof of concept for metabolism-based cell sorting, we further identified HSCs within the Lineage-cKit+Sca1+ (KLS) hematopoietic stem/progenitor population using MOBs and a machine-learning algorithm. Moreover, we revealed the dynamic changes of MOBs, and the association of longer τ with enhanced glycolysis under HSC stemness-maintaining conditions during HSC culture. Our work thus provides a new paradigm to identify and track the metabolism of single HSCs non-invasively and in real time.
代谢是造血干细胞（HSC）功能的关键调节因子。目前缺乏评估单个造血干细胞代谢的实时、非侵入性方法。利用荧光寿命成像显微镜，我们从代谢辅酶NAD(P)H和FAD的自发荧光特性开发了一套代谢光学生物标志物（MOB）。这些MOB揭示了造血干细胞增强的糖酵解、低氧化代谢以及独特的线粒体定位。重要的是，酶结合的NAD(P)H的荧光寿命（τ）可以非侵入性地监测单个造血干细胞中的糖酵解/乳酸脱氢酶活性。作为基于代谢的细胞分选概念验证，我们使用MOB和机器学习算法进一步在谱系-cKit+Sca1+（KLS）造血干/祖细胞群体中鉴定出造血干细胞。此外，我们揭示了MOB的动态变化，以及在造血干细胞培养过程中，在维持造血干细胞干性的条件下，较长的τ与增强的糖酵解之间的关联。因此，我们的工作提供了一种新的范例，可用于非侵入性地实时识别和跟踪单个造血干细胞的代谢。
