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Klotho protects chondrocyte viability via FOXO1/3 in osteoarthritis
Abstract
Purpose: To investigate the effect of Klotho and FOXO1/3 on the CH viability in OA.
Methods: The survival rate of CHs, Klotho and FOXO1/3 protein expression, and ROS production were measured in the OA cartilages of different degenerative phases. H2O2 was also used to injure CHs, and the cell viability, Klotho and FOXO1/3 expressions, as well as ROS levels were investigated to clarify the effect of exogenic Klotho on the injured CHs. Additionally, in order to verify the role of FOXO1/3 in Klotho-treated CHs, SOD2, GPX1, inflammatory factors, collagen I/II, SOX9, and Runx-2 levels were analyzed by silencing FOXO1 and FOXO3 expression via siRNA transfection.
Results: Klotho and FOXO1/3 expressions significantly decreased, and ROS production increased in severely human OA cartilage (p <0.05). Besides, H2O2 affected CHs viability with the suppression of Klotho and FOXO1/3 expression but ROS production was elevated. Exogenic Klotho application partly reversed the injury caused by H2O2. Furthermore, Klotho treatment of the injured CHs contributed to SOD2 and GPX1 expressions, and suppressed IL-1β, IL-6, TNF-α and MMP-13 production, resulting in the upregulation of collagen II and SOX9 as well as downregulation of collagen I and Runx-2. However, the protective effect of Klotho was weakened by FOXO1 and FOXO3 gene silencing.
Conclusion: Klotho protects CHs viability by suppressing oxidative stress and inflammation, which is associated with the mediation of FOXO1 and FOXO3. These findings provide new insights into the treatment of OA.