†Department of Chemistry, National University of Singapore, Singapore 117543.
‡State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
J Am Chem Soc. 2015 May 13;137(18):5930-8. doi: 10.1021/jacs.5b00042. Epub 2015 May 4.
Hypochlorous acid (HOCl), as a highly potent oxidant, is well-known as a key "killer" for pathogens in the innate immune system. Recently, mounting evidence indicates that intracellular HOCl plays additional important roles in regulating inflammation and cellular apoptosis. However, the organelle(s) involved in the distribution of HOCl remain unknown, causing difficulty to fully exploit its biological functions in cellular signaling pathways and various diseases. One of the main reasons lies in the lack of effective chemical tools to directly detect HOCl at subcellular levels due to low concentration, strong oxidization, and short lifetime of HOCl. Herein, the first two-photon fluorescent HOCl probe (TP-HOCl 1) and its mitochondria- (MITO-TP) and lysosome- (LYSO-TP) targetable derivatives for imaging mitochondrial and lysosomal HOCl were reported. These probes exhibit fast response (within seconds), good selectivity, and high sensitivity (<20 nM) toward HOCl. In live cell experiments, both probes MITO-TP and LYSO-TP were successfully applied to detect intracellular HOCl in corresponding organelles. In particular, the two-photon imaging of MITO-TP and LYSO-TP in murine model shows that higher amount of HOCl can be detected in both lysosome and mitochondria of macrophage cells during inflammation condition. Thus, these probes could not only help clarify the distribution of subcellular HOCl, but also serve as excellent tools to exploit and elucidate functions of HOCl at subcellular levels.
次氯酸（HOCl）作为一种强氧化剂，是先天免疫系统中病原体的主要“杀伤者”。最近，越来越多的证据表明，细胞内 HOCl 在调节炎症和细胞凋亡方面发挥着额外的重要作用。然而，参与 HOCl 分布的细胞器尚不清楚，这使得充分发挥其在细胞信号通路和各种疾病中的生物学功能变得困难。主要原因之一是由于 HOCl 浓度低、氧化能力强和寿命短，缺乏有效的化学工具来直接在亚细胞水平检测 HOCl。在此，我们报道了第一个双光子荧光 HOCl 探针（TP-HOCl 1）及其可靶向线粒体（MITO-TP）和溶酶体（LYSO-TP）的衍生物，用于成像线粒体和溶酶体中的 HOCl。这些探针对 HOCl 具有快速响应（在几秒钟内）、良好的选择性和高灵敏度（<20 nM）。在活细胞实验中，探针 MITO-TP 和 LYSO-TP 都成功地应用于检测相应细胞器中的细胞内 HOCl。特别是，MITO-TP 和 LYSO-TP 的双光子成像在炎症条件下显示，巨噬细胞细胞中的溶酶体和线粒体中可以检测到更多的 HOCl。因此，这些探针不仅可以帮助阐明亚细胞 HOCl 的分布，而且还可以作为在亚细胞水平上开发和阐明 HOCl 功能的优秀工具。
