Ishii Sho, Kishi Mikiya, Yamagami Keigo, Okada Shinji, Abe Keiko, Misaka Takumi
Central Research Institute, Mizkan Group Co., Handa, Aichi, Japan.
Biosci Biotechnol Biochem. 2012;76(3):523-9. doi: 10.1271/bbb.110824.
Acetic acid induces unique physiological responses in mammalian cells. Our previous study found that fura-2-loaded human embryonic kidney (HEK) 293T cells showed a robust intracellular fluorescence response immediately after stimulation with acetic acid, and no such response in the case of citric acid. In the present study, we aimed to identify the unique characteristics of acetic acid responsible for this phenomenon. We found that one such feature is its hydrophobicity. We also discovered that acetic acid induces cell responses by intracellular acidification. Of the components of acetic acid in solution (protons, acetate ions, and undissociated acetic acid), undissociated acetic acid might be the functional unit that penetrates the lipid bilayer of cell membranes to acidify the intracellular environment, thereby inducing cell responses. The method used in this study might be convenient in evaluating the intracellular acidification of cultured cells by acids in the external environment.
乙酸在哺乳动物细胞中会引发独特的生理反应。我们之前的研究发现，用乙酸刺激后，负载fura-2的人胚肾（HEK）293T细胞会立即呈现强烈的细胞内荧光反应，而柠檬酸刺激时则无此反应。在本研究中，我们旨在确定导致这一现象的乙酸独特特性。我们发现其中一个特性是其疏水性。我们还发现乙酸通过细胞内酸化诱导细胞反应。在乙酸溶液的成分（质子、乙酸根离子和未离解的乙酸）中，未离解的乙酸可能是穿透细胞膜脂质双层以酸化细胞内环境从而诱导细胞反应的功能单元。本研究中使用的方法可能便于评估外界环境中的酸对培养细胞的细胞内酸化作用。
