N-Cadherin Attenuates High Glucose-Induced Nucleus Pulposus Cell Senescence Through Regulation of the ROS/NF-κB Pathway

Background/Aims: Diabetes mellitus (DM) is a potential etiology of disc degeneration. N-cadherin (N-CDH) helps maintain the cell viability, cell phenotype and matrix biosynthesis of nucleus pulposus (NP) cells. Here, we mainly aimed to investigate whether N-CDH can attenuate high glucose-induced NP cell senescence and its potential mechanism. Methods: Rat NP cells were cultured in a base culture medium and base culture medium with a 0.2 M glucose concentration. Recombinant lentiviral vectors were used to enhance N-CDH expression in NP cells. Senescence-associated beta-galactosidase (SA-beta-Gal) activity was measured by SA-beta-Gal staining. NP cell proliferation was evaluated by CCK-8 assay. Telomerase activity and intracellular reactive oxygen species (ROS) content were tested by specific chemical kits according to the manufacturer's instructions. G0/G1 cell cycle arrest was evaluated by flow cytometry. Real-time PCR and Western blotting were used to analyze mRNA and protein expressions of senescence markers (p16 and p53) and matrix macromolecules (aggrecan and collagen II). Additionally, p-NF-kappa B expression was also analyzed by Western blotting to evaluate NF-kappa B pathway activity. Results: High glucose significantly decreased N-CDH expression, increased ROS generation and NF-kappa B pathway activity, and promoted NP cell senescence, which was reflected in the increase in SA-beta-Gal activity and senescence marker (p16 and p53) expression, compared to the control group. High glucose decreased telomerase activity and cell proliferation potency. However, N-CDH overexpression partially attenuated NP cell senescence, decreased ROS content and inhibited the activation of the NF-kappa B pathway under the high glucose condition. Conclusion: High glucose decreases N-CDH expression and promotes NP cell senescence. N-CDH overexpression can attenuate high glucose-induced NP cell senescence through the regulation of the ROS/NF-kappa B pathway. This study suggests that N-CDH is a potential therapeutic target to slow DM-mediated disc NP degeneration. (c) 2018 The Author(s) Published by S. Karger AG, Basel.