Department of Biophysics, Institute of Physics, Maria Curie-Skłodowska University, Lublin, Poland.
Department of Biophysics, Institute of Biology and Biochemistry, Maria Curie-Skłodowska University, Lublin, Poland.
Sci Rep. 2018 Sep 14;8(1):14067. doi: 10.1038/s41598-018-32301-9.
Amphotericin B is an antibiotic used in pharmacotherapy of life-threatening mycotic infections. Unfortunately, the applicability of this antibiotic is associated with highly toxic side effects. In order to understand molecular mechanisms underlying toxicity of amphotericin B to patients, two cell lines, human normal colon epithelial cells (CCD 841 CoTr) and human colon adenocarcinoma cells (HT-29) were cultured in the presence of the drug and imaged with the application of fluorescence lifetime imaging microscopy and Raman scattering microscopy. The results of the cell viability assays confirm high toxicity of amphotericin B towards human cells. The images recorded demonstrate effective binding of amphotericin B to biomembranes. Analysis of the images reveals the operation of a defence mechanism based upon the elimination of molecules of the drug from living cells via formation of small amphotericin B-containing lipid vesicles. The fact that exosomes formed are devoid of cholesterol, as concluded on the basis of the results of Raman analysis, suggests that sequestration of sterols from the lipid phase of biomembranes is not a sole mechanism responsible for the toxic side effects of amphotericin B. Alternatively, the results imply that molecules of the drug present directly within the hydrophobic membrane core disturb the lipid membrane structure and affect their biological functions.
两性霉素 B 是一种用于治疗危及生命的真菌性感染的抗生素。不幸的是，这种抗生素的适用性与高度毒性的副作用有关。为了了解两性霉素 B 对患者毒性的分子机制，将两种细胞系，人正常结肠上皮细胞（CCD 841 CoTr）和人结肠腺癌细胞（HT-29）在药物存在的情况下进行培养，并应用荧光寿命成像显微镜和拉曼散射显微镜进行成像。细胞活力测定的结果证实了两性霉素 B 对人细胞的高毒性。记录的图像表明两性霉素 B 与生物膜有效结合。对图像的分析揭示了一种防御机制的运作，该机制基于通过形成小的含有两性霉素 B 的脂质囊泡从活细胞中去除药物分子。根据拉曼分析的结果得出的结论是，形成的外体不含胆固醇，这表明从生物膜的脂质相中隔离固醇不是两性霉素 B 毒性副作用的唯一机制。相反，结果表明药物分子直接存在于疏水性膜核中会干扰脂质膜结构并影响其生物学功能。
