Overexpression of SOX9 alleviates the progression of human osteoarthritis in vitro and in vivo

Abstract

Purpose

Recent findings have identified that SOX9 served as a key role during the pathogenesis of osteoarthritis (OA). This study aimed to investigate the mechanisms by which SOX9 regulated the formation of OA in vitro and in vivo.

Materials and methods

The relative expressions of SOX9 in patients with OA and normal fracture of thighbone were analyzed by real-time-PCR. In vitro, IL-1β induced inflammatory response in human chondrocytes was used to evaluate the function of SOX9. The recombinant SOX9 lentivirus vector (Lenti-SOX9) was used to upregulate the expression of SOX9 in cells. ELISA was used to measure the concentration of tumor necrosis factor-α (TNF-α). The protein expressions of SOX9, matrix metalloproteinase-13 (MMP13), Collagen II, Aggrecan and Smad3 were analyzed by Western blot. Cell proliferation and cell apoptosis were detected by CCK-8 assay and flow cytometry, respectively. In vivo, the effect of SOX9 on surgically induced OA mice was evaluated.

Results

The gene level of SOX9 was remarkably downregulated in patients with OA compared with normal people, while the concentration of TNF-α was upregulated. In addition, IL-1β reduced the expressions of SOX9, Collagen II and Aggrecan and increased the level of MMP13 in chondrocytes. Moreover, Lenti-SOX9 notably inhibited IL-1β-induced growth inhibition and apoptosis in chondrocytes via increasing the expression of Smad3. Finally, Lenti-SOX9 markedly alleviated the symptoms of OA mice in vivo.

Conclusion

Upregulation of SOX9 inhibited IL-1β-induced inflammatory response via increasing the level Smad3 in human chondrocytes and exhibited therapeutic effect on surgically induced OA mice in vivo. Therefore, SOX9 may serve as a potential target in the treatment of OA in the future.

Keywords:

• SOX9
• osteoarthritis
• collagen
• inflammation
• IL-1β

Acknowledgment

The study was supported by the Projects of National Science Foundation of China (Grant Nos. 81570992 and 81571261), the Projects of National Science Foundation of Shanghai, China (Grant No. 17401901000), SUMHS Seed Foundation Project (Grant No. HMSF-16-21-010), Science and Technology Development Foundation of Pudong New District, Shanghai, China (Grant Nos. PKJ2016-Y55 and PWZxq2017-03), and the study was also partly sponsored by the Interdisciplinary Program of Shanghai JiaoTong University (No. YG2017MS22, YG2017QN56 and YG2016QN22), the Program of Shanghai Sixth People’s Hospital East Campus Foundation (No. 2019YY001), the Program of Shanghai Sixth People’s Hospital Foundation (No. LY2Y0272), the Shanghai Three-year Action plan to Further Accelerate the Development of Traditional Chinese Medicine (2018-2020) No. ZY 2018-2020-FWTX-8009).

Disclosure

The authors declare that they have no competing financial interests in this work.