Peroxiredoxin 6 protects irradiated cells from oxidative stress and shapes their senescence-associated cytokine landscape

Abstract

Cellular senescence is a complex stress response defined as an essentially irreversible cell cycle arrest mediated by the inhibition of cell cycle-specific cyclin dependent kinases. The imbalance in redox homeostasis and oxidative stress have been repeatedly observed as one of the hallmarks of the senescent phenotype. However, a large-scale study investigating protein oxidation and redox signaling in senescent cells in vitro has been lacking. Here we applied a proteome-wide analysis using SILAC-iodoTMT workflow to quantitatively estimate the level of protein sulfhydryl oxidation and proteome level changes in ionizing radiation-induced senescence (IRIS) in hTERT-RPE-1 cells. We observed that senescent cells mobilized the antioxidant system to buffer the increased oxidation stress. Among the antioxidant proteins with increased relative abundance in IRIS, a unique 1-Cys peroxiredoxin family member, peroxiredoxin 6 (PRDX6), was identified as an important contributor to protection against oxidative stress. PRDX6 silencing increased ROS production in senescent cells, decreased their resistance to oxidative stress-induced cell death, and impaired their viability. Subsequent SILAC-iodoTMT and secretome analysis after PRDX6 silencing showed the downregulation of PRDX6 in IRIS affected protein secretory pathways, decreased expression of extracellular matrix proteins, and led to unexpected attenuation of senescence-associated secretory phenotype (SASP). The latter was exemplified by decreased secretion of pro-inflammatory cytokine IL-6 which was also confirmed after treatment with an inhibitor of PRDX6 iPLA2 activity, MJ33. In conclusion, by combining different methodological approaches we discovered a novel role of PRDX6 in senescent cell viability and SASP development. Our results suggest PRDX6 could have a potential as a drug target for senolytic or senomodulatory therapy.

Synergism of BCL-2 family inhibitors facilitates selective elimination of senescent cells

“…The age-dependent accumulation of senescent cells is caused by age-related attenuated efficiency of the immune system [16] and their higher resistance both to extrinsic and intrinsic pro-apoptotic stimuli [16][17][18], including oxidative stress [19]. While the mechanisms driving senescence are well studied, understanding the mechanisms endowing these cells with increased survival capacity is limited.…”

Peroxiredoxin, Senescence, and Cancer

“…Multiple types of stimulations, such as chemotherapy and radiation, can induce senescent cells to secrete high levels of interleukins, inflammatory cytokines, proteases, and growth factors, which are collectively referred to as senescence-associated secretory phenotype (SASP) [ 104 ]. A recent study using ionizing radiation-induced senescence (IRIS) cell model demonstrated that PRX6 is an important contributor to protection against oxidative-stress-induced cell death in senescent cells by attenuation of senescence-associated proinflammatory cytokine IL-6 secretion [ 105 ]. SASP can either promote or inhibit cancer, depending on the SASP composition.…”

“…In addition, IL-6 is the most prominent cytokine of the SASP. PRX6 silencing decreased expression of extracellular matrix proteins including IL6 in IRIS hTERT-RPE-1 cells [ 105 ].…”

The Relaxin-3 Receptor, RXFP3, Is a Modulator of Aging-Related Disease

“…Maintaining cellular protein homeostasis, or proteostasis, requires the well-coordinated control of protein synthesis, folding, conformational integrity, and ultimately degradation. Proteostasis activities coordinate these diverse processes across the lifespan of all organisms [125]. The proteostatic regulatory network ensures that cells have the proteins they need, while minimizing misfolding or aggregation events that are hallmarks of aging-associated proteinopathies, such as Alzheimer's, Parkinson's, and Huntington's disease [126][127][128][129][130].…”