OGT-induced O-GlcNAcylation of NEK7 protein aggravates osteoarthritis progression by enhancing NEK7/NLRP3 axis

Abstract

Backgrounds

The role of O-GlcNAc transferase (OGT)-induced O-linked N-acetylglucosaminylation (O-GlcNAcylation) has been reported in multiple human diseases. However, its specific functions in osteoarthritis (OA) progression remain undetermined.

Objective

This study focused on the target proteins of OGT-induced O-GlcNAcylation in OA and the specific functional mechanism.

Methods

The levels of total O-GlcNAc and OGT were measured in both in vitro and in vivo OA models using western blot. The effects of OGT knockout on OA progression were detected through Safranin O staining, immunohistochemical staining and OARSI score evaluation. The effects of OGT silencing on LPS-induced chondrocyte injury were assessed by performing loss-of function assays. Co-immunoprecipitation (co-IP) was conducted to verify the effect of OGT-induced O-GlcNAcylation on the interaction between NEK7 and NLRP3. The role of OGT in modulating the O-GlcNAcylation and phosphorylation levels of NEK7 was analysed using western blot.

Results

The OGT-indued O-GlcNAcylation level was increased in both in vitro and in vivo OA models. Knockout of OGT mitigated OA progression in model mice. Additionally, silencing of OGT suppressed LPS-induced chondrocyte pyroptosis. Moreover, silencing of OGT inhibited the O-GlcNAcylation and enhanced the phosphorylation of NEK7 at S260 site, thereby blocking the binding of NEK7 with NLRP3.

Conclusion

OGT-induced NEK7 O-GlcNAcylation promotes OA progression by promoting chondrocyte pyroptosis via the suppressing interaction between NEK7 and NLRP3.

Keywords:

• OGT
• O-GlcNAcylation
• NEK7
• NLRP3
• OA

Authors’ contributions

All authors participated in the design, interpretation of the studies and analysis of the data and review of the manuscript. C H and Q W drafted the work and revised it critically for important intellectual content; Z Z, Y Y, H H and M H were responsible for the acquisition, analysis, or interpretation of data for the work; S L made substantial contributions to the conception or design of the work. All authors read and approved the final manuscript.

Disclosure statement

The authors declare that they have no competing interests.

Ethics approval and consent to participate

All procedures of animal experiments were approved by the Ethics Committee of The First Affiliated Hospital of Gannan Medical University. All animal experiments should comply with the ARRIVE guidelines.

Availability of data and materials

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Additional information

Funding

This study is supported by Project of Natural Science Foundation of Jiangxi Province [No.20212BAB206076], Science&Technology Innovation Project of Gannan Medical University [No.TS202003], Project of Education Department of Jiangxi Province [No. GJJ190785] and Project of Health Commission of Jiangxi Province [No.20204486]