Department of Biochemistry and Molecular Biology, University of Salamanca, Salamanca, Spain.
Cell Death Differ. 2010 Dec;17(12):1842-54. doi: 10.1038/cdd.2010.67. Epub 2010 Jun 4.
Transient reactive oxygen species (ROS) production is currently proving to be an important mechanism in the regulation of intracellular signalling, but reports showing the involvement of ROS in important biological processes, such as cell differentiation, are scarce. In this study, we show for the first time that ROS production is required for megakaryocytic differentiation in K562 and HEL cell lines and also in human CD34(+) cells. ROS production is transiently activated during megakaryocytic differentiation, and such production is abolished by the addition of different antioxidants (such as N-acetyl cysteine, trolox, quercetin) or the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor diphenylene iodonium. The inhibition of ROS formation hinders differentiation. RNA interference experiments have shown that a p22(phox)-dependent NADPH oxidase activity is responsible for ROS production. In addition, the activation of ERK, AKT and JAK2 is required for differentiation, but the activation of phosphatidylinositol 3-kinase and c-Jun N-terminal kinase seems to be less important. When ROS production is prevented, the activation of these signalling pathways is partly inhibited. Taken together, these results show that NADPH oxidase ROS production is essential for complete activation of the main signalling pathways involved in megakaryocytopoiesis to occur. We suggest that this might also be important for in vivo megakaryocytopoiesis.
瞬时活性氧（ROS）的产生目前被证明是细胞内信号转导调节的一个重要机制，但关于 ROS 参与细胞分化等重要生物学过程的报道却很少。在本研究中，我们首次表明，ROS 的产生对于 K562 和 HEL 细胞系以及人 CD34(+)细胞中的巨核细胞分化是必需的。ROS 的产生在巨核细胞分化过程中短暂激活，而这种产生会被不同的抗氧化剂（如 N-乙酰半胱氨酸、trolox、槲皮素）或烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶抑制剂二苯基碘鎓所抑制。ROS 形成的抑制会阻碍分化。RNA 干扰实验表明，p22(phox)依赖性 NADPH 氧化酶活性负责 ROS 的产生。此外，ERK、AKT 和 JAK2 的激活对于分化是必需的，但磷脂酰肌醇 3-激酶和 c-Jun N-末端激酶的激活似乎不那么重要。当 ROS 的产生被阻止时，这些信号通路的激活也会受到部分抑制。综上所述，这些结果表明，NADPH 氧化酶 ROS 的产生对于完全激活巨核细胞生成中涉及的主要信号通路是必需的。我们认为，这对于体内巨核细胞生成也可能很重要。
