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RelA/p65 inhibition prevents tendon adhesion by modulating inflammation, cell proliferation, and apoptosis
Shuai Chen1, Shichao Jiang2, Wei Zheng1
1Department of Orthopaedics, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, 600 Yishan Road, Shanghai 200233, People's Republic of China.
Abstract:
Peritendinous tissue fibrosis which leads to poor tendon function is a worldwide clinical problem; however, its mechanism remains unclear. Transcription factor RelA/p65, an important subunit in the NF-κB complex, is known to have a critical role in many fibrotic diseases. Here, we show that RelA/p65 functions as a core fibrogenic regulator in tendon adhesion and that its inhibition exerts an anti-fibrogenic effect on peritendinous adhesion. We detected the upregulation of the NF-κB pathway in human tendon adhesion using a gene chip microarray assay and revealed the overexpression of p65 and extracellular matrix (ECM) proteins Collagen I, Collagen III, and α-smooth muscle actin (α-SMA) in human fibrotic tissues by immunohistochemistry and western blotting. We also found that in a rat model of tendon injury, p65 expression correlated with tendon adhesion, whereas its inhibition by small interfering (si)RNA prevented fibrous tissue formation and inflammatory reaction as evidenced by macroscopic, biomechanical, histological, immunohistochemical, and western blotting analyses. Furthermore, in cultured fibroblasts, p65-siRNA, p65-specific inhibitor, Helenalin and JSH23 suppressed cell proliferation and promoted apoptosis, whereas inhibiting the mRNA and protein expression of ECM components and cyclo-oxygenase-2, an inflammatory factor involved in tendon adhesion. Our findings indicate that p65 has a critical role in peritendinous tissue fibrosis and suggest that p65 knockdown may be a promising therapeutic approach to prevent tendon adhesion.
Insights
RelA/p65, a key factor in fibrosis, drives tendon adhesion. Inhibiting p65 reduces fibrosis and inflammation, offering a potential therapeutic strategy for tendon adhesion.
Area of Science:
- Biomedical Science
- Molecular Biology
- Tissue Engineering
Background:
- Peritendinous tissue fibrosis impairs tendon function globally.
- The precise mechanisms underlying tendon fibrosis remain largely unknown.
- Nuclear factor-kappa B (NF-κB) pathway, specifically the RelA/p65 subunit, is implicated in various fibrotic conditions.
Purpose of the Study:
- To investigate the role of RelA/p65 in peritendinous tissue fibrosis and tendon adhesion.
- To evaluate the anti-fibrogenic potential of inhibiting RelA/p65 in tendon adhesion.
Main Methods:
- Gene chip microarray assay to detect NF-κB pathway activation in human tendon adhesion.
- Immunohistochemistry and western blotting to assess p65 and extracellular matrix (ECM) protein expression.
- Rat tendon injury model with p65 inhibition using small interfering (si)RNA, followed by macroscopic, biomechanical, histological, and molecular analyses.
- In vitro studies on cultured fibroblasts using p65-siRNA and specific inhibitors (Helenalin, JSH23).
Main Results:
- Upregulation of the NF-κB pathway and overexpression of p65, Collagen I, Collagen III, and α-smooth muscle actin (α-SMA) in human tendon adhesion tissues.
- Inhibition of p65 in a rat model significantly reduced fibrous tissue formation and inflammation.
- p65 inhibition in cultured fibroblasts suppressed proliferation, promoted apoptosis, and decreased ECM and inflammatory factor expression (cyclo-oxygenase-2).
Conclusions:
- RelA/p65 acts as a central regulator in peritendinous tissue fibrosis and tendon adhesion.
- Targeting p65 demonstrates significant anti-fibrotic and anti-inflammatory effects.
- p65 knockdown presents a promising therapeutic avenue for preventing and treating tendon adhesion.