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 , People's Republic of China.
College of Chemical Engineering , Xiangtan University , Xiangtan 411105 , People's Republic of China.
ACS Sens. 2018 Nov 26;3(11):2311-2319. doi: 10.1021/acssensors.8b00567. Epub 2018 Nov 9.
Nitric oxide (NO) is a vital gaseous signal molecule and plays an important role in diverse physiological and pathological processes including regulation of vascular functions. Endoplasmic reticulum (ER) stress is caused by the accumulation of misfolded or unfolded protein in the ER. Besides, ER stress induced by NO can be involved in the pathogenesis of various vascular diseases. Unfortunately, to the best of our knowledge, no ER-targeting probe for NO is reported to study the relationship between ER stress and the level of NO in a biological system. Herein, an ER-targeted fluorescent probe named ER-Nap-NO for imaging of NO is designed and synthesized. ER-Nap-NO consists of three main parts: naphthalimide (two-photon fluorophore), o-phenylenediamino (NO recognition group), and methyl sulfonamide (ER-targetable group). The probe itself is nonfluorescent because a photoinduced electron transfer (PET) process exists. After the addition of NO, the PET process is inhibited and thus strong fluorescence is released. Moreover, the response mechanism is confirmed by H NMR and mass spectra and DFT calculation in detail. In addition, from the experimental results, we can conclude that the probe displays several obvious advantages including high sensitivity, selectivity, and ER-targetable ability. Based on these excellent properties, the probe is used for the two-photon imaging of exogenous and endogenous NO in ER of living cells. Most importantly, the ER-targetable probe has potential capability as a tool for investigating the level of NO during tunicamycin-induced ER stress in cells and tissues, which is beneficial for revealing the role of NO in ER-associated vascular diseases.
一氧化氮（NO）是一种重要的气态信号分子，在多种生理和病理过程中发挥重要作用，包括调节血管功能。内质网（ER）应激是由于 ER 中错误折叠或未折叠的蛋白质积累引起的。此外，NO 诱导的 ER 应激可参与多种血管疾病的发病机制。不幸的是，据我们所知，目前尚无用于研究 ER 应激与生物系统中 NO 水平之间关系的 ER 靶向 NO 探针。在此，设计并合成了一种用于 NO 成像的 ER 靶向荧光探针 ER-Nap-NO。ER-Nap-NO 由三个主要部分组成：萘酰亚胺（双光子荧光团）、邻苯二胺（NO 识别基团）和甲磺酰胺（ER 靶向基团）。探针本身没有荧光，因为存在一个光诱导电子转移（PET）过程。加入 NO 后，PET 过程被抑制，从而释放出强荧光。此外，通过 1H NMR 和质谱以及 DFT 计算详细证实了响应机制。此外，从实验结果可以得出结论，该探针具有高灵敏度、选择性和 ER 靶向能力等几个明显优势。基于这些优异的性能，该探针用于活细胞 ER 中外源和内源性 NO 的双光子成像。最重要的是，该 ER 靶向探针具有作为工具研究细胞和组织中衣霉素诱导的 ER 应激期间 NO 水平的潜力，这有利于揭示 NO 在 ER 相关血管疾病中的作用。
