Novel functions of the Glutaredoxin (Grx) System in the Lens




Zhang, Jinmin
Dang, Terry
Yu, Yu
Wu, Hongli


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Purpose: The purpose of this study is to evaluate the function and therapeutic potential of the glutaredoxin (Grx) system, both glutaredoxin 1 (Grx1) and glutaredoxin 2 (Grx2), using Grx1/Grx2 double knockout (DKO) mice as a model. Methods: We isolated primary LECs from wild-type (WT) and DKO mice for in vitro studies including cell proliferation assays, cell cycle distribution analysis via flow cytometry, cell apoptosis via western blot and ELISA kit, mitochondrial function evaluation via ATP bioluminescence assay, expression levels of mitochondrial complexes I-V, and seahorse mito stress test, cell cytoskeleton visualization using a fluorescence microscope. Results: We found that DKO cells displayed a much slower proliferation rate compared to WT cells. The population of DKO cells in the G2/M phase was two-fold higher than that of WT cells. On the other hand, the population of DKO cells in the S phase was 50% less than that of WT cells. Additionally, DKO cells are pro-apoptotic under non-stressed condition as indicated by higher levels of Bax and cytochrome C. For the mitochondrial function, lower ATP production, less expression of mitochondrial complex III subunit UQCRC2 and complex IV subunit MTCO1 (CIV-MTCO1), lower coupling efficiency, and higher proton leak were presented in DKO cells as compared to WT cells, indicating multi-dimensional mitochondrial dysfunction in DKO cells. As for the cell cytoskeletal organization, we found that DKO cells had microtubule polarization because of the higher levels of vimentin expression which is an indicator of nuclei degeneration inhibition during the lens cell differentiation. Conclusion: Overall, we found slow cell proliferation, cell cycle arrest, and mitochondrial dysfunction in the LECs from DKO mice. Our data indicate Grx system plays an important role in maintaining the normal function of mLECs, and Grx system activation might serve as a new therapeutic strategy for cataract prevention.


Research Appreciation Day Award Winner - HSC College of Pharmacy, 2023 Pharmaceutical Science Research Award - 2nd Place