Induction of cellular autophagy impairs TGF-β1-mediated extracellular matrix deposition in primary human knee fibroblasts
Aims: To evaluate the role of autophagy in primary knee fibroblasts undergoing myofibroblast differentiation as an in vitro model of arthrofibrosis, a complication after total knee arthroplasty characterized by aberrant intra-articular scar tissue formation and limited range of motion. Methods: We...
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| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
The British Editorial Society of Bone & Joint Surgery
2025-04-01
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| Series: | Bone & Joint Research |
| Subjects: | |
| Online Access: | https://online.boneandjoint.org.uk/doi/epdf/10.1302/2046-3758.144.BJR-2024-0312.R1 |
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| Summary: | Aims: To evaluate the role of autophagy in primary knee fibroblasts undergoing myofibroblast differentiation as an in vitro model of arthrofibrosis, a complication after total knee arthroplasty characterized by aberrant intra-articular scar tissue formation and limited range of motion. Methods: We conducted a therapeutic screen of autophagic-modulating therapies in primary human knee fibroblasts undergoing transforming growth factor-beta 1 (TGF-β1)-mediated myofibroblast differentiation. Autophagy was induced pharmacologically with rapamycin or by amino acid deprivation. Picrosirius red staining was performed to quantify collagen deposition. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blotting were conducted to evaluate fibrotic gene expression levels. Results: Rapamycin, an mTOR complex 1 (mTORC1) inhibitor and autophagy inducer, reduced TGF-β1-mediated collagen deposition. Interestingly, we simultaneously report that myofibrogenic genes, including ACTA2, were highly upregulated following rapamycin-TGF-β1 treatment. When autophagy was induced through amino acid deprivation, we demonstrated suppressed extracellular matrix levels, fibrotic gene expression (e.g. ACTA2), and SMAD2 phosphorylation levels in TGF-β1-stimulated fibroblasts. Conclusion: Our findings demonstrate that the induction of cellular autophagy suppresses TGF-β1-induced collagen deposition in primary human knee fibroblasts. Taken together, these data suggest that cellular autophagy may be prophylactic against the pathogenesis of arthrofibrosis. Cite this article: Bone Joint Res 2025;14(4):328–337. |
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| ISSN: | 2046-3758 |