Glutaredoxin-1 Silencing Induces Cell Senescence via p53/p21/p16 Signaling Axis

Glutaredoxin-1 (Grxl) catalyzes deglutathionylation with glutathione as a cofactor. Accumulating evidence indicates important roles for Grxl and S-glutathionylation in the aging process; however, further exploration of Grxl-regulated cellular processes is important to understand the functions of Grxl in aging. In the present study, we constructed stable Grxl knockdown or overexpression human cell lines. Grxl silencing significantly decreased the cellular ratio of reduced glutathione (GSH) to oxidized glutathione (GSSG) (GSH/GSSG ratio), resulting in excessive reactive oxygen species (ROS) accumulation, whereas Grxl overexpression decreased cellular ROS levels. Grxl silencing also increased glutathionylation of DJ-1 and HSP60, contributing to decreased mitochondrial spare respiration capacity and ATP production. We applied quantitative proteomics to identify differentially expressed proteins between Grxl knockdown and control cells and showed that Grxl silencing inactivated DNA replication and damage repair pathways. p53 signaling was activated by Grxl silencing, which inhibited the CDK4-mediated G1-S transition, resulting in GI phase cell-cycle arrest and cell senescence, a known hallmark of aging. Taken together, our results indicate that Grxl regulates DNA replication and damage repair processes and is a potential therapeutic target for aging-related diseases.