The Key Laboratory of Life-Organic Analysis; Key Laboratory of Pharmaceutical Intermediates and Analysis of Natural Medicine, College of Chemistry and Chemical Engineering, Qufu Normal University , Qufu 273165, China.
Key Laboratory of Coastal Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences , Yantai 264003, China.
Anal Chem. 2017 Aug 15;89(16):8509-8516. doi: 10.1021/acs.analchem.7b02164. Epub 2017 Jul 24.
The cells control their pH change in a very accurate range. pH plays important roles in cell autophagy and apoptosis. Previous evidence implies that the internal milieu of a tumor is acidified. Although the acidification in cells is investigated, the biological effects from multiple stimulating factors under the complex intracellular environment have not been thoroughly elaborated yet. Currently, there are few pH probes that perform in a wide acidity range, and a probe that is capable of measuring a wide pH range needs to be developed. Herein, we report two new fluorescent probes (BHNBD and CM-BHNBD) for the detection of mitochondrial and intramucosal acidification. The two probes respond to pH via an H-driven TICT (twist intramolecular charge transfer) mechanism, and they can linearly report pH within a wide pH range: 7.00-2.00 following ∼148-fold fluorescence increase. The two probes also possess excellent membrane permeability, good photostability, and negligible cytotoxicity. The probes are successfully applied for quantifying the acidification in HeLa cells under the simultaneous stimulation of nutrient deprivation and oxidative stress. Our results demonstrate that the mitochondrial pH is in a dynamic fluctuating state during the acidification process, which suggests a potential cross-talk effect between cell autophagy and apoptosis. We also use the probes for quantifying the intramucosal pH variation in stomach and esophagus via manipulating cellular proton pump. The development of our probes is potentially expected to be used to monitor the intracellular/intramucosal acidification for biomedical research.
细胞在非常精确的范围内控制其 pH 值变化。pH 值在细胞自噬和细胞凋亡中起着重要作用。先前的证据表明，肿瘤的内部环境是酸化的。尽管已经研究了细胞内的酸化，但在复杂的细胞内环境下，多种刺激因素的生物学效应尚未得到充分阐述。目前，能够在宽酸度范围内工作的 pH 探针很少，需要开发能够测量宽 pH 范围的探针。在此，我们报告了两种用于检测线粒体和细胞内酸化的新型荧光探针（BHNBD 和 CM-BHNBD）。这两种探针通过 H 驱动的 TICT（扭转分子内电荷转移）机制对 pH 值做出响应，并且可以在线性范围内报告宽 pH 值范围：7.00-2.00，荧光强度增加约 148 倍。这两种探针还具有出色的膜通透性、良好的光稳定性和可忽略不计的细胞毒性。探针成功应用于同时在营养剥夺和氧化应激刺激下定量测定 HeLa 细胞的酸化。我们的结果表明，在酸化过程中线粒体 pH 值处于动态波动状态，这表明细胞自噬和细胞凋亡之间可能存在交叉对话效应。我们还使用探针通过操纵细胞质子泵来定量胃和食管的细胞内 pH 值变化。我们探针的开发有望用于监测生物医学研究中的细胞内/细胞内酸化。
