Guo Han-Wen, Yu Jia-Sin, Hsu Shu-Han, Wei Yau-Huei, Lee Oscar K, Dong Chen-Yuan, Wang Hsing-Wen
National Yang-Ming University, Institute of Biophotonics, 155 Li-Nong Street, Section 2, Taipei 112, TaiwanbNational Taiwan University, Department of Physics, 1 Roosevelt Road, Section 4, Taipei 106, Taiwan.
National Yang-Ming University, Institute of Biophotonics, 155 Li-Nong Street, Section 2, Taipei 112, Taiwan.
J Biomed Opt. 2015 Jan;20(1):017004. doi: 10.1117/1.JBO.20.1.017004.
Reduced nicotinamide adenine dinucleotide (NADH) fluorescence lifetime has been broadly used as a metabolic indicator for stem cell imaging. However, the direct relationship between NADH fluorescence lifetime and metabolic pathway and activity remains to be clarified. In this study, we measured the NADH fluorescence lifetime of human mesenchymal stem cells (hMSCs) as well as the metabolic indictors, such as adenosine triphosphate (ATP) level, oxygen consumption, and lactate release, up to 4 weeks under normal osteogenic differentiation and oxidative phosphorylation-attenuated/inhibited differentiation by oligomycin A (OA) treatment. NADH fluorescence lifetime was positively correlated with oxygen consumption and ATP level during energy transformation from glycolysis to oxidative phosphorylation. Under OA treatment, oxidative phosphorylation was attenuated/inhibited (i.e., oxygen consumption remained the same as controls or lower), cells showed attenuated differentiation under glycolysis, and NADH fluorescence lifetime change was not detected. Increased expression of the overall complex proteins was observed in addition to Complex I. We suggested special caution needs to be exercised while interpreting NADH fluorescence lifetime signal in terms of stemcell differentiation.
还原型烟酰胺腺嘌呤二核苷酸（NADH）荧光寿命已被广泛用作干细胞成像的代谢指标。然而，NADH荧光寿命与代谢途径及活性之间的直接关系仍有待阐明。在本研究中，我们测量了人间充质干细胞（hMSCs）的NADH荧光寿命以及代谢指标，如三磷酸腺苷（ATP）水平、耗氧量和乳酸释放，在正常成骨分化以及用寡霉素A（OA）处理使氧化磷酸化减弱/抑制的分化条件下，长达4周的时间内这些指标的变化情况。在从糖酵解向氧化磷酸化的能量转换过程中，NADH荧光寿命与耗氧量和ATP水平呈正相关。在OA处理下，氧化磷酸化减弱/抑制（即耗氧量与对照相同或更低），细胞在糖酵解下的分化减弱，且未检测到NADH荧光寿命变化。除了复合体I外，还观察到整体复合体蛋白的表达增加。我们建议在根据干细胞分化来解释NADH荧光寿命信号时需格外谨慎。
