Tokyo University of Pharmacy and Life Sciences, Horinouchi, Hachioji, Tokyo, Japan.
Arch Biochem Biophys. 2012 Feb 1;518(1):89-94. doi: 10.1016/j.abb.2011.12.009. Epub 2011 Dec 19.
We clarified whether actin cytoskeleton is involved in the macrophage apoptosis induced by cationic liposomes composed of stearylamine (SA-liposomes). Externalization of phosphatidylserine induced by SA-liposomes was suppressed by cytochalasin D, a specific inhibitor of polymerization of F-actin. Furthermore, activation of PKCδ and reactive oxygen species (ROS) generation, which could be involved in the macrophage apoptosis, were inhibited by cytochalasin D. Microscopical observation revealed the co-localization of 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiI)-labeled SA-liposomes and fluorescein-labeled phalloidin, which specifically binds to F-actin, and this co-localization was also inhibited by cytochalasin D. Co-localization of SA-liposomes and F-actin was also inhibited by the pre-treatment of cells with chondroitinase ABC. These findings could be the first observation concerning the contribution of the proteoglycan-actin cytoskeleton-ROS generation pathway to apoptosis induced by SA-liposomes in macrophages.
我们阐明了肌动蛋白细胞骨架是否参与了由硬脂胺（SA-脂质体）组成的阳离子脂质体诱导的巨噬细胞凋亡。细胞松弛素 D，一种 F-肌动蛋白聚合的特异性抑制剂，抑制了 SA-脂质体诱导的磷脂酰丝氨酸外翻。此外，细胞松弛素 D 还抑制了 PKCδ 的激活和活性氧（ROS）的产生，这可能与巨噬细胞凋亡有关。显微镜观察显示，DiI 标记的 SA-脂质体和荧光标记的鬼笔环肽（特异性结合 F-肌动蛋白）的共定位被细胞松弛素 D 抑制。细胞松弛素 D 还抑制了 SA-脂质体和 F-肌动蛋白的共定位。用软骨素酶 ABC 预处理细胞也抑制了 SA-脂质体和 F-肌动蛋白的共定位。这些发现可能是关于蛋白聚糖-肌动蛋白细胞骨架-ROS 生成途径对巨噬细胞中 SA-脂质体诱导的凋亡的贡献的首次观察。
