Universidade Federal do Par, Instituto de Cincias Biolgicas, Laboratrio de Biologia Estrutural, Belm, Par, Brazil.
Cell Biol Int. 2011 Apr;35(4):335-43. doi: 10.1042/CBI20100083.
KA (kojic acid) is a secondary metabolite isolated from Aspergillus fungi that has demonstrated skin whitening, antioxidant and antitumour properties among others. However, limited information is available regarding its effects on macrophages, the major cell involved in cell defence. The aim of the present study was to analyse whether KA affects functional properties related to macrophage activation, such as phagocytosis and spreading ability over a substrate. Treatment of resident macrophages with 50 μg/ml KA for 1 h induced both morphological and physiological alterations in cells. Immunofluorescence microscopy revealed enhanced cell spreading and an increase in cell surface exposure, associated with a rearrangement of microtubules, actin filaments and intermediate filaments. KA also potentiated phagocytosis by macrophages, as demonstrated by the increase in phagocytic activity towards yeast, when compared to untreated cells. KA increased the production of ROS (reactive oxygen species), but not NO (nitric oxide) production. Three tests were used to assess cell viability; MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide], NR (neutral red) uptake and PI (propidium iodide) exclusion test, which showed that macrophages maintain their viability following KA treatment. Results indicate that KA can modulate macrophage activation through cytoskeleton rearrangement, increase cell surface exposure, enhance the phagocytic process and ROS production. The study demonstrates a new role for KA as a macrophage activator.
KA（曲酸）是一种从曲霉真菌中分离出来的次级代谢产物，具有皮肤美白、抗氧化和抗肿瘤等特性。然而，关于它对巨噬细胞的影响的信息有限，巨噬细胞是参与细胞防御的主要细胞。本研究旨在分析 KA 是否会影响与巨噬细胞激活相关的功能特性，如吞噬作用和在基质上的扩散能力。用 50μg/ml 的 KA 处理驻留巨噬细胞 1 小时，会诱导细胞发生形态和生理改变。免疫荧光显微镜显示细胞伸展增强，细胞表面暴露增加，与微管、肌动蛋白丝和中间丝的重排有关。KA 还增强了巨噬细胞的吞噬作用，与未处理的细胞相比，吞噬酵母的吞噬活性增加。KA 增加了 ROS（活性氧）的产生，但不增加 NO（一氧化氮）的产生。使用三种测试来评估细胞活力；MTT [3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴化物]、NR（中性红）摄取和 PI（碘化丙啶）排除试验，结果表明 KA 处理后巨噬细胞保持活力。结果表明，KA 可以通过细胞骨架重排、增加细胞表面暴露、增强吞噬过程和 ROS 产生来调节巨噬细胞的激活。该研究证明了 KA 作为巨噬细胞激活剂的新作用。
