2. Academic Validation
  3. PPARγ activation suppresses chondrocyte ferroptosis through mitophagy in osteoarthritis

PPARγ activation suppresses chondrocyte ferroptosis through mitophagy in osteoarthritis

  • J Orthop Surg Res. 2023 Aug 24;18(1):620. doi: 10.1186/s13018-023-04092-x.
Xiang Xue # 1,  Tianming Dai # 2,  Junyan Chen 3,  Yangyang Xu 3,  Zhenyu Yang 1,  Jian Huang 4,  Wuyan Xu 1,  Siming Li 5,  Qingqi Meng 6
Affiliations

Affiliations

  • 1 Department of Orthopedics, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, China.
  • 2 Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, China.
  • 3 Guizhou Medical University, Guiyang, China.
  • 4 Department of Traumatic Orthopedics, The Central Hospital of Xiaogan, Xiaogan, China.
  • 5 Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, China. drsmli@163.com.
  • 6 Guangzhou Institute of Traumatic Surgery, Guangzhou Red Cross Hospital of Jinan University, Guangzhou, China. mengqingqi@jnu.edu.cn.
  • # Contributed equally.
PMID: 37620972 DOI: 10.1186/s13018-023-04092-x
Abstract

Background: Osteoarthritis (OA) is a prevalent disease plaguing the elderly. Recently, chondrocyte Ferroptosis has been demonstrated to promote the progression of OA. Peroxisome proliferator-activated receptor-γ (PPARγ) is an important factor in maintaining cartilage health. However, the relationship between PPARγ and chondrocyte Ferroptosis in OA and its mechanism is completely unclear.

Methods: We established a surgically induced knee OA rat model to investigate PPARγ and chondrocyte Ferroptosis in OA. Rat knee specimens were collected for Safranin O/Fast Green staining and immunohistochemical staining after administered orally placebo or pioglitazone (PPARγ Agonist) for 4 weeks. We used RSL3 to establish a chondrocyte Ferroptosis model cultured in vitro to study the role of PPARγ activation toward Ferroptosis, mitochondrial function, and PTEN-induced putative kinase 1 (Pink1)/Parkin-dependent Mitophagy. GW9662 (PPARγ Antagonist), Mdivi-1 (Mitophagy inhibitor), and chloroquine (Mitophagy inhibitor) were employed to investigate the mechanism of PPARγ-Pink1/Parkin-dependent Mitophagy in the inhibition of Ferroptosis.

Results: We found that PPARγ activation by pioglitazone attenuated not only OA but also inhibited the expression of the Ferroptosis marker acyl-CoA synthetase long-chain family member 4 (ACSL4) at the same time in rats. Furthermore, in vivo and in vitro data indicated that PPARγ activation restored Pink1/Parkin-dependent Mitophagy, improved mitochondrial function, inhibited chondrocyte Ferroptosis, and delayed the progression of OA.

Conclusions: The present study demonstrated that PPARγ activation attenuates OA by inhibiting chondrocyte Ferroptosis, and this chondroprotective effect was achieved by promoting the Pink1/Parkin-dependent Mitophagy pathway.

Keywords

Chondrocyte; Ferroptosis; Mitophagy; Osteoarthritis; PPARγ; Pink1.

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