Glyoxal Induces Senescence in Human Keratinocytes through Oxidative Stress and Activation of the Protein Kinase B/FOXO3a/p27^KIP1 Pathway

Senescence is a well-characterized cellular state associated with specific markers such as permanent cell proliferation arrest and the secretion of messenger molecules by cells expressing the senescence-associated secretory phenotype. The senescence-associated secretory phenotype composition depends on many factors such as the cell type or the nature of the stress that induces senescence. Because the skin constitutes a barrier with the external environment, it is particularly subjected to different types of stresses and consequently prone to premature cellular aging. The dicarbonyl compounds glyoxal (GO) and methylglyoxal are precursors of advanced glycation end products, whose presence marks normal and pathological aging. In this study, we show that GO treatment provokes oxidative stress by increasing ROS and advanced glycation end-products levels and induces senescence in human keratinocytes. Furthermore, GO-induced senescence bears a unique molecular progression profile: an early-stage senescence when protein kinase B‒FOXO3a-p27^KIP1 pathway mediates cell cycle arrest and a late-stage senescence maintained by the p16^INK4/pRb pathway. Moreover, we characterized the resulting secretory phenotype during early-stage senescence by mass spectrometry. Our study provides evidence that GO can affect keratinocyte functions and act as a driver of human skin aging. Hence, senotherapeutics aimed at modulating GO-associated senescence phenotype hold promising potential.