mTORC2 inhibition by JR-AB2-011 improves IL-1β-induced inflammation, catabolic response, and apoptosis in human chondrocytes through IκB-α/NF-κB p65

• Published in: Cellular and Molecular Biology Vol. 70; no. 9; pp. 37 - 43
• Main Authors: Temiz-Resitoglu, Meryem, Sabrie, Zainab, Tiftik, Rukiye Nalan, Kalkan, Taskın, Aktas-Sukuroglu, Ayca, Malik, Kafait U, Sahan-Firat, Seyhan
• Format: Journal Article
• Language: English
• Published: France 08.10.2024
• Subjects: Apoptosis - drug effects; Cells, Cultured; Chondrocytes - drug effects; Chondrocytes - metabolism; Humans; Imidazoles; Inflammation - metabolism; Inflammation - pathology; Interleukin-1beta - metabolism; Mechanistic Target of Rapamycin Complex 2 - antagonists & inhibitors; Mechanistic Target of Rapamycin Complex 2 - metabolism; NF-KappaB Inhibitor alpha - metabolism; Osteoarthritis - drug therapy; Osteoarthritis - metabolism; Osteoarthritis - pathology; Proto-Oncogene Proteins c-akt - metabolism; Quinoxalines; Rapamycin-Insensitive Companion of mTOR Protein - genetics; Rapamycin-Insensitive Companion of mTOR Protein - metabolism; Signal Transduction - drug effects; Transcription Factor RelA - metabolism; Tumor Necrosis Factor-alpha - metabolism
• DOI: 10.14715/cmb/2024.70.9.5
• ISSN: 0145-5680; 1165-158X

Osteoarthritis (OA) is a very common chronic joint condition marked by inflammation and cartilage loss. mTOR is a well-known mediator of inflammation, cell survival, and aging; however, its role in OA has not been determined. To explore the role of mTORC2 in OA-and associated pathological changes, we examined the contribution of mTORC2-mediated Akt, rictor and IκB-α/NF-κB p65 pathway in interleukin (IL)-1β-treated human chondrocytes. We focused on the protein expression of proinflammatory cytokines and catabolic and apoptotic factors, including TNF-α, IL-6, iNOS, MMP13, Bax, and caspase3, which may occur through this signalling pathway in IL-1β-treated chondrocytes. Chondrocytes were cultured and treated with either 2 ng/mL IL‑1β alone or in combination with increasing concentrations of JR-AB2-011 (50, 100, or 250 µM), a selective mTORC2 inhibitor. The protein levels of phosphorylated (p)‑Akt, Akt, rictor, p-NF-κB p65, NF-κB p65, IκB-α, p-IκB-α, iNOS, MMP13, Bax, and caspase3 were evaluated by Western blotting. In IL-1β-stimulated chondrocytes, mTORC2 activity was increased with increased phosphorylation of Akt and expression of rictor. IL-1β increased the expression of p-IκBα, p-NF-κB p65, NF-κB p65, IL-6, TNF-α, iNOS, Bax, and caspase3 proteins and decreased the expression of IκB-α. All of these IL-1β-induced alterations were prevented by JR-AB2-011. The main novel finding in the present study is that selective mTORC2 inhibition by JR-AB2-011 prevents the inflammatory, catabolic, and apoptotic responses induced by IL-1β via modulation of IκB-α/NF-κB activity. Therefore, we demonstrated a previously unknown function of mTORC2 inhibition that seems to be a potential therapeutic target for OA.