Department of Biochemistry & Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
J Biol Chem. 2021 Nov;297(5):101257. doi: 10.1016/j.jbc.2021.101257. Epub 2021 Sep 29.
Healing of cutaneous wounds requires the collective migration of epithelial keratinocytes to seal the wound bed from the environment. However, the signaling events that coordinate this collective migration are unclear. In this report, we address the role of phosphorylation of eukaryotic initiation factor 2 (eIF2) and attendant gene expression during wound healing. Wounding of human keratinocyte monolayers in vitro led to the rapid activation of the eIF2 kinase GCN2. We determined that deletion or pharmacological inhibition of GCN2 significantly delayed collective cell migration and wound closure. Global transcriptomic, biochemical, and cellular analyses indicated that GCN2 is necessary for maintenance of intracellular free amino acids, particularly cysteine, as well as coordination of RAC1-GTP-driven reactive oxygen species (ROS) generation, lamellipodia formation, and focal adhesion dynamics following keratinocyte wounding. In vivo experiments using mice deficient for GCN2 validated the role of the eIF2 kinase during wound healing in intact skin. These results indicate that GCN2 is critical for appropriate induction of collective cell migration and plays a critical role in coordinating the re-epithelialization of cutaneous wounds.
皮肤伤口的愈合需要上皮角质形成细胞的集体迁移，以将伤口床与环境隔离。然而，协调这种集体迁移的信号事件尚不清楚。在本报告中，我们研究了真核起始因子 2（eIF2）磷酸化及其在伤口愈合过程中伴随的基因表达的作用。体外培养的人角质形成细胞单层的伤口处理导致 eIF2 激酶 GCN2 的快速激活。我们确定 GCN2 的缺失或药理学抑制显著延迟了细胞的集体迁移和伤口闭合。全面的转录组学、生化和细胞分析表明，GCN2 对于维持细胞内游离氨基酸（特别是半胱氨酸）以及协调 RAC1-GTP 驱动的活性氧（ROS）生成、片状伪足形成和角质形成细胞损伤后的焦点粘连动力学是必需的。使用缺乏 GCN2 的小鼠进行的体内实验验证了该 eIF2 激酶在完整皮肤伤口愈合过程中的作用。这些结果表明，GCN2 对于适当诱导细胞的集体迁移是至关重要的，并在协调皮肤伤口的再上皮化过程中起着关键作用。
