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He X, Jarrell ZR, Liang Y, Ryan Smith M, Orr ML, Marts L, Go YM, Jones DP. Vanadium pentoxide induced oxidative stress and cellular senescence in human lung fibroblasts. Redox Biol 2022; 55:102409. [PMID: 35870339 PMCID: PMC9307685 DOI: 10.1016/j.redox.2022.102409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/30/2022] [Accepted: 07/12/2022] [Indexed: 11/25/2022] Open
Abstract
Both environmental exposure to vanadium pentoxide (V2O5, V+5 for its ionic counterparts) and fibroblast senescence are associated with pulmonary fibrosis, but whether V+5 causes fibroblast senescence remains unknown. We found in a dose-response study that 2-40 μM V+5 caused human lung fibroblasts (HLF) senescence with increased senescence-associated β-galactosidase activity and p16 expression, while cell death occurred at higher concentration (LC50, 82 μM V+5). Notably, measures of reactive oxygen species (ROS) production with fluorescence probes showed no association of ROS with V+5-dependent senescence. Preloading catalase (polyethylene-conjugated), a H2O2 scavenger, did not alleviate the cellular senescence induced by V+5. Analyses of the cellular glutathione (GSH) system showed that V+5 oxidized GSH, increased GSH biosynthesis, stimulated cellular GSH efflux and increased protein S-glutathionylation, and addition of N-acetyl cysteine inhibited V+5-elevated p16 expression, suggesting that thiol oxidation mediates V+5-caused senescence. Moreover, strong correlations between GSSG/GSH redox potential (Eh), protein S-glutathionylation, and cellular senescence (R2 > 0.99, p < 0.05) were present in V+5-treated cells. Studies with cell-free and enzyme-free solutions showed that V+5 directly oxidized GSH with formation of V+4 and GSSG in the absence of O2. Analyses of V+5 and V+4 in HLF and culture media showed that V+5 was reduced to V+4 in cells and that a stable V+4/V+5 ratio was rapidly achieved in extracellular media, indicating ongoing release of V+4 and reoxidation to V+5. Together, the results show that V+5-dependent fibroblast senescence is associated with a cellular/extracellular redox cycling mechanism involving the GSH system and occurring under conditions that do not cause cell death. These results establish a mechanism by which environmental vanadium from food, dietary supplements or drinking water, can cause or contribute to lung fibrosis in the absence of high-level occupational exposures and cytotoxic cell death.
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Affiliation(s)
- Xiaojia He
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Zachery R Jarrell
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Yongliang Liang
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Matthew Ryan Smith
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Michael L Orr
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Lucian Marts
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA
| | - Young-Mi Go
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA.
| | - Dean P Jones
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University, Atlanta, GA, 30322, USA.
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