Xu Shuai, Liu Hong-Wen, Yin Xia, Yuan Lin, Huan Shuang-Yan, Zhang Xiao-Bing
Molecular Science and Biomedicine Laboratory , State Key Laboratory of Chemo/Biosensing and Chemometrics , College of Chemistry and Chemical Engineering , Collaborative Innovation Center for Chemistry and Molecular Medicine , Hunan University , Changsha , 410082 , P. R. China . Email:
Key Laboratory for Green Organic Synthesis and Application of Hunan Province , Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education , College of Chemistry , Xiangtan University , Xiangtan 411105 , P. R. China.
Chem Sci. 2018 Oct 10;10(1):320-325. doi: 10.1039/c8sc03584a. eCollection 2019 Jan 7.
Carbon monoxide (CO) acts as an important gasotransmitter in delivering intramolecular and intermolecular signals to regulate a variety of physiological processes. This lipid-soluble gas can freely pass through the cell membrane and then diffuse to adjacent cells acting as a messenger. Although many fluorescent probes have been reported to detect intracellular CO, it is still a challenge to visualize the release behavior of endogenous CO. The main obstacle is the lack of a probe that can anchor onto the cell membrane while having the ability to image CO in real time. In this work, by grafting a polar head onto a long and linear hydrophobic Nile Red molecule, a cell membrane-anchored fluorophore was developed. This design strategy of a cell membrane-anchored probe is simpler than the traditional one of using a long hydrophobic alkyl chain as a membrane-anchoring group, and endows the probe with better water solubility. could rapidly bind to the cell membrane (within 1 min) and displayed a long retention time. was then converted to a CO-responsive fluorescent probe () by complexation with palladium based on a metal palladium-catalyzed reaction. exhibited a fast response to CO with a 25-fold fluorescence enhancement . The detection limit was calculated to be 0.23 μM, indicating that is sensitive enough to image endogenous CO. Notably, showed excellent cell membrane-anchoring ability. With , the release of CO from HepG2 cells under LPS- and heme-stimulated conditions was visualized and the cell self-protection effect during a drug-induced hepatotoxicity process was also studied. Moreover, was successfully applied to the detection of intracellular CO in several cell lines and tissues, and the results demonstrated that the liver is the main organ for CO production, and that cancer cells release more CO from their cells than normal cells. is the first membrane-anchored CO fluorescent probe that has the ability to reveal the relationship between CO release and diseases. It also has prospects for the studying of intercellular signaling functions of CO.
一氧化碳（CO）作为一种重要的气体信号分子，在传递分子内和分子间信号以调节多种生理过程中发挥着作用。这种脂溶性气体能够自由穿过细胞膜，然后扩散到相邻细胞，充当信使。尽管已有许多荧光探针被报道用于检测细胞内的CO，但可视化内源性CO的释放行为仍然是一个挑战。主要障碍在于缺乏一种既能锚定在细胞膜上又能实时成像CO的探针。在这项工作中，通过将一个极性头部嫁接到长链线性疏水尼罗红分子上，开发了一种细胞膜锚定荧光团。这种细胞膜锚定探针的设计策略比传统的使用长疏水烷基链作为膜锚定基团的策略更简单，并且赋予了探针更好的水溶性。[探针名称1]能够迅速结合到细胞膜上（在1分钟内）并显示出较长的保留时间。然后基于金属钯催化反应，通过与钯络合将[探针名称1]转化为一种对CO有响应的荧光探针（[探针名称2]）。[探针名称2]对CO表现出快速响应，荧光增强了25倍。计算得出检测限为0.23μM，表明[探针名称2]对成像内源性CO足够灵敏。值得注意的是，[探针名称2]表现出优异的细胞膜锚定能力。利用[探针名称2]，可视化了脂多糖（LPS）和血红素刺激条件下HepG2细胞中CO的释放，并且还研究了药物诱导肝毒性过程中的细胞自我保护作用。此外，[探针名称2]成功应用于几种细胞系和组织中细胞内CO的检测，结果表明肝脏是产生CO的主要器官，并且癌细胞比正常细胞释放更多的CO。[探针名称2]是首个具有揭示CO释放与疾病之间关系能力的膜锚定CO荧光探针。它在研究CO的细胞间信号传导功能方面也具有前景。
