HSF1 Increases EOGT-Mediated Glycosylation of Notch1 to Promote IL-1β-Induced Inflammatory Injury of Chondrocytes

• Published in: Cartilage 2024-02, p.19476035241229211
• Main Authors: Huang, Yuanchi, Pan, Wenjie, Bao, Huanli, Sun, Xiangxiang, Xu, Chao, Ma, Jianbing
• Format: Article
• Language: English
• Subjects: Original
• ISSN: 1947-6035; 1947-6043; 1947-6043
• DOI: 10.1177/19476035241229211

Osteoarthritis (OA) is the most common arthritic disease in humans. Nevertheless, the pathogenic mechanism of OA remains unclear. This study aimed to explore that heat-shock transcription factor 1 (HSF1) facilitated interleukin-1 beta (IL-1β) chondrocyte injury by increasing Notch1 O-linked -acetylglucosamine (O-GlcNAc) modification level. Human chondrocytes were incubated with 5 ng/ml interleukin-1 beta (IL-1β) for 24 h to establish OA cell model. The messenger RNA (mRNA) or protein expressions were assessed using reverse transcription-quantitative polymerase chain reaction, western blot, or immunofluorescence. Chondrocyte viability was examined by Cell Counting Kit-8 assay. Enzyme-linked immunosorbent assay was employed to detect the secretion levels of interleukin-6 (IL-6) and interleukin-8 (IL-8). Immunoprecipitation was adopted to detect Notch1 O-GlcNAc modification level. The interaction between HSF1 and epidermal growth factor-like (EGF) domain-specific O-GlcNAc transferase (EOGT) promoter was analyzed by dual-luciferase reporter gene and chromatin immunoprecipitation assays. Herein, our results demonstrated that HSF1, EOGT, Notch1, and Notch1 intracellular domain (NICD1) expressions in chondrocytes were markedly increased by IL-1β stimulation. EOGT elevated Notch1 expression in IL-1β-treated chondrocytes by increasing Notch1 O-GlcNAc modification level. EOGT silencing reduced IL-1β-induced chondrocyte inflammatory injury. In addition, HSF1 knockdown relieved IL-1β-induced chondrocyte inflammatory injury. Molecular interaction experiment proved that HSF1 transcriptionally activated EOGT expression in IL-1β-treated chondrocytes. HSF1 promoted IL-1β-induced inflammatory injury in chondrocytes by increasing EOGT-mediated glycosylation of Notch1.