Age-related cataract: GSTP1 ubiquitination and degradation by Parkin inhibits its anti-apoptosis in lens epithelial cells
- Biochim Biophys Acta Mol Cell Res. 2023 Mar 3;119450. doi: 10.1016/j.bbamcr.2023.119450.
- 1. Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong 226001, Jiangsu, China.
- 2. Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong 226001, Jiangsu, China. Electronic address: [email protected].
- 3. Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong 226001, Jiangsu, China. Electronic address: [email protected].
Purpose: Oxidative stress-induced Apoptosis of lens epithelial cells (LECs) contributes to the pathogenesis of age-related cataract (ARC). The purpose of this research is to underlie the potential mechanism of E3 Ligase Parkin and its oxidative stress-associated substrate in cataractogenesis.
Methods: The central anterior capsules were obtained from patients with ARC, Emory mice, and corresponding controls. SRA01/04 cells were exposed to H2O2 combined with cycloheximide (a translational inhibitor), MG-132 (a Proteasome Inhibitor), chloroquine (an Autophagy inhibitor), Mdivi-1 (a mitochondrial division inhibitor), respectively. Co-immunoprecipitation was employed to detect protein-protein interactions and ubiquitin-tagged protein products. Levels of proteins and mRNA were evaluated by western blotting and quantitative RT-PCR assays.
Results: Glutathione-S-transferase P1 (GSTP1) was identified as a novel Parkin substrate. Compared with corresponding controls, GSTP1 was significantly decreased in the anterior lens capsules obtained from human cataracts and Emory mice. Similarly, GSTP1 was declined in H2O2-stimulated SRA01/04 cells. Ectopic expression of GSTP1 mitigated H2O2-induced Apoptosis, whereas silencing GSTP1 aggregated Apoptosis. In addition, H2O2 stimulation and Parkin overexpression could promote the degradation of GSTP1 through the ubiquitin-proteasome system, autophagy-lysosome pathway, and Mitophagy. After co-transfection with Parkin, the non-ubiquitinatable GSTP1 mutant maintained its anti-apoptotic function, while wildtype GSTP1 failed. Mechanistically, GSTP1 might promote mitochondrial fusion through upregulating Mitofusins 1/2 (MFN1/2).
Conclusion: Oxidative stress induces LECs Apoptosis via Parkin-regulated degradation of GSTP1, which may provide potential targets for ARC therapy.