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Updated: Aug 28, 2025
Tissue Collection and RNA Extraction from the Human Osteoarthritic Knee Joint
Published on: July 22, 2021
Single cell RNA-seq analysis identifies ferroptotic chondrocyte cluster and reveals TRPV1 as an anti-ferroptotic
Zhongyang Lv1, Jie Han2, Jiawei Li1
1State Key Laboratory of Pharmaceutical Biotechnology, Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing 210008, Jiangsu, PR China.
Background:
Osteoarthritis (OA) is the most common degenerative joint disease primarily characterized by cartilage destruction. The aim of this study was to investigate the role, molecular characteristics and potential therapeutic target of chondrocyte ferroptosis in the pathogenesis of OA.
Methods:
The expression of ferroptotic hallmarks (iron and lipid peroxidation accumulation, glutathione deletion) were analyzed in paired intact and damaged cartilages from OA patients. Single cell RNA sequencing (scRNA-seq) analysis was performed on 17,638 chondrocytes to verify the presence, investigate the molecular signatures and unveil the potential therapeutic target of ferroptotic chondrocyte cluster in human OA cartilages. Destabilization of medial meniscus (DMM)-induced OA model and tert-butyl hydroperoxide (TBHP)-treated primary mouse chondrocytes and human cartilage explants were used to evaluate the protective effect of pharmacologically activated transient receptor potential vanilloid 1 (TRPV1). The downstream molecular mechanisms of TRPV1 was further investigated in glutathione peroxidase 4 (Gpx4) heterozygous genetic deletion mice (Gpx4+/-).
Findings:
The concentrations of iron and lipid peroxidation and the expression of ferroptotic drivers in the damaged areas of human OA cartilages were significantly higher than those in the intact cartilage. scRNA-seq analysis revealed a chondrocyte cluster characterized by preferentially expressed ferroptotic hallmarks and genes, namely ferroptotic chondrocyte cluster. Comprehensive gene set variation analysis revealed TRPV1 as an anti-ferroptotic target in human OA cartilage. Pharmacological activation of TRPV1 significantly abrogated cartilage degeneration by protecting chondrocytes from ferroptosis. Mechanistically, TRPV1 promoted the expression of GPX4, and its anti-ferroptotic role was largely mitigated in the OA model of Gpx4+/- mice.
Interpretation:
TRPV1 activation protects chondrocytes from ferroptosis and ameliorates OA progression by upregulating GPX4.
Funding:
National Key R&D Program of China (2018YFC1105904), Key Program of NSFC (81730067), National Science Foundation of China (81772335, 81941009, 81802196), Natural Science Foundation of Jiangsu Province, China (BK20180127), Jiangsu Provincial Key Medical Talent Foundation, Six Talent Peaks Project of Jiangsu Province (WSW-079).
Insights
Transient Receptor Potential Vanilloid 1 (TRPV1) activation protects cartilage cells from ferroptosis, a cell death process. This finding offers a potential new therapeutic strategy for osteoarthritis (OA) by upregulating glutathione peroxidase 4 (GPX4).
Area of Science:
- Biomedical Sciences
- Molecular Biology
- Cell Biology
Background:
- Osteoarthritis (OA) is a prevalent degenerative joint disease marked by cartilage destruction.
- Chondrocyte ferroptosis, a specific form of cell death, is implicated in OA pathogenesis.
- Investigating chondrocyte ferroptosis offers potential therapeutic targets for OA.
Purpose of the Study:
- To explore the role and molecular characteristics of chondrocyte ferroptosis in OA.
- To identify potential therapeutic targets for OA within ferroptotic chondrocytes.
- To evaluate the protective effect of Transient Receptor Potential Vanilloid 1 (TRPV1) activation against OA.
Main Methods:
- Analyzed ferroptotic hallmarks (iron, lipid peroxidation, glutathione) in human OA cartilage.
- Performed single-cell RNA sequencing (scRNA-seq) on 17,638 chondrocytes to identify ferroptotic clusters.
- Utilized DMM-induced OA models and TBHP-treated chondrocytes/explants to assess TRPV1's protective effects, investigating downstream mechanisms via Gpx4 heterozygous mice.
Main Results:
- Damaged OA cartilage showed significantly higher iron, lipid peroxidation, and ferroptosis drivers than intact cartilage.
- scRNA-seq identified a distinct chondrocyte cluster exhibiting ferroptotic characteristics.
- TRPV1 activation protected against cartilage degeneration by inhibiting chondrocyte ferroptosis, mechanistically linked to GPX4 upregulation.
Conclusions:
- TRPV1 activation serves as an anti-ferroptotic target in human OA cartilage.
- TRPV1 activation protects chondrocytes from ferroptosis, thereby ameliorating OA progression.
- The protective mechanism involves TRPV1 upregulating GPX4 expression.
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