Research Paper Advance Articles

Downregulation of microRNA-29b by DNMT3B decelerates chondrocyte apoptosis and the progression of osteoarthritis via PTHLH/CDK4/RUNX2 axis

Pengcheng Dou1, *, , Yu He2, *, , Bo Yu3, , Juan Duan4, ,

  • 1 Department of Orthopedics, The Second Xiangya Hospital, Central South University, Changsha 410011, P.R. China
  • 2 Department of Radiology, The Second Xiangya Hospital, Central South University, Changsha 410011, P.R. China
  • 3 Department of Critical Care Medicine, The Second Xiangya Hospital, Central South University, Changsha 410011, P.R. China
  • 4 Department of Geriatrics, The Second Xiangya Hospital, Central South University, Changsha 410011, P.R. China
* Equal contribution

Received: February 25, 2020       Accepted: May 27, 2020       Published: November 7, 2020      

https://doi.org/10.18632/aging.103778
How to Cite

Copyright: © 2020 Dou et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

The correlation between DNA methyltransferases (DNMTs) and microRNAs (miRNAs) has been well-established, but its interaction in osteoarthritis (OA) has been barely clarified. This study aimed to analyze the relationship between DNMT3B and miR-29b as well as their implications in OA. Our results revealed that DNMT3B was downregulated while miR-29b was upregulated in OA cartilage tissues relative to normal cartilage tissues. Hypermethylation of specific CpG sites in the miR-29b promoter region induced by DNMT3B contributed to downregulation of miR-29b in OA chondrocytes. Furthermore, luciferase activity determination demonstrated that miR-29b targeted and negatively regulated the parathyroid hormone-like hormone (PTHLH). Moreover, the PTHLH upregulation induced by miR-29b methylation led to the enhancement of chondrocyte growth and suppression of their apoptosis and extracellular matrix degradation, which was achieved by the upregulation cyclin-dependent kinase 4 (CDK4) expression. Co-IP suggested that CDK4 induced ubiquitination of RUNX2, which could be enhanced by DNMT3B. In the OA mouse model induced by destabilization of the medial meniscus, overexpression of DNMT3B was observed to downregulate the expression of RUNX2 whereby preventing OA-induced loss of chondrocytes. Hence, the DNMT3B/miR-29b/PTHLH/CDK4/RUNX2 axis was found to be involved in the apoptosis of chondrocytes induced by OA, highlighting a novel mechanism responsible for OA progression.

Abbreviations

OA: Osteoarthritis; ECM: extracellular matrix; PTHLH: parathyroid hormone-like hormone; CDK4: cyclin-dependent kinase 4; RUNX2: runt-related gene 2; ECM: extracellular matrix; miRNAs: microRNAs; DNMT3B: DNA methyltransferase 3B.