Inhibition of nuclear factor-erythroid 2-related factor (Nrf2) by caveolin-1 promotes stress-induced premature senescence.

Abstract

Reactive oxygen species (ROS) can induce premature cellular senescence, which is believed to contribute to aging and age-related diseases. The nuclear erythroid 2 p45-related factor-2 (Nrf2) is a transcription factor that mediates cytoprotective responses against stress. We demonstrate that caveolin-1 is a direct binding partner of Nrf2, as shown by the binding of the scaffolding domain of caveolin-1 (amino acids 82-101) to the caveolin-binding domain of Nrf2 (amino acids 281-289). Biochemical studies show that Nrf2 is concentrated into caveolar membranes in human and mouse fibroblasts, where it colocalizes with caveolin-1, under resting conditions. After oxidative stress, caveolin-1 limits the movement of Nrf2 from caveolar membranes to the nucleus. In contrast, Nrf2 is constitutively localized to the nucleus before and after oxidative stress in caveolin-1-null mouse embryonic fibroblasts (MEFs), which do not express caveolin-1. Functional studies demonstrate that caveolin-1 acts as an endogenous inhibitor of Nrf2, as shown by the enhanced up-regulation of NQO1, an Nrf2 target gene, in caveolin-1-null MEFs and the activation or inhibition of a luciferase construct carrying an antioxidant responsive element (ARE) after down-regulation of caveolin-1 by small interfering RNA or overexpression of caveolin-1, respectively. Expression of a mutant form of Nrf2 that cannot bind to caveolin-1 (Φ→A-Nrf2) hyperactivates ARE and inhibits oxidative stress-induced activation of the p53/p21(Waf1/Cip1) pathway and induction of premature senescence in fibroblasts. Finally, we show that overexpression of caveolin-1 in colon cancer cells inhibits oxidant-induced activation of Nrf2-dependent signaling, promotes premature senescence, and inhibits their transformed phenotype. Thus, by inhibiting Nrf2-mediated signaling, caveolin-1 links free radicals to the activation of the p53/senescence pathway.

• Authors: Daniela Volonte, Zhongmin Liu, Paul M Musille, Elena Stoppani, Nobunao Wakabayashi, Yuan-Pu Di, Michael P Lisanti, Thomas W Kensler, Ferruccio Galbiati
• Journal: Molecular biology of the cell (Mol Biol Cell) Vol. 24 Issue 12 Pg. 1852-62 (Jun 2013) ISSN: 1939-4586 [Electronic] United States
• PMID: 23637463 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Caveolin 1
• NF-E2-Related Factor 2
• Oxidants
• Hydrogen Peroxide

Topics

• Active Transport, Cell Nucleus (drug effects)
• Animals
• Caveolae (metabolism)
• Caveolin 1 (genetics, metabolism)
• Cell Line
• Cell Nucleus (metabolism)
• Cells, Cultured
• Cellular Senescence (drug effects)
• Embryo, Mammalian (cytology)
• Fibroblasts (cytology, drug effects, metabolism)
• HCT116 Cells
• Humans
• Hydrogen Peroxide (pharmacology)
• Immunoblotting
• Mice
• Mice, Knockout
• Microscopy, Fluorescence
• NF-E2-Related Factor 2 (genetics, metabolism)
• NIH 3T3 Cells
• Oxidants (pharmacology)
• Oxidative Stress
• Protein Binding
• RNA Interference