Toggle Main Menu Toggle Search

Open Access padlockePrints

Specific isoforms of the ubiquitin ligase gene WWP2 are targets of osteoarthritis genetic risk via a differentially methylated DNA sequence

Lookup NU author(s): Jack Roberts, Olivia Boldvig, Guillaume Aubourg, Sai Kanchenapally, Professor David Deehan, Dr Sarah RiceORCiD, Professor John LoughlinORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Background Transitioning from a genetic association signal to an effector gene and a targetable molecular mechanism requires the application of functional fine-mapping tools such as reporter assays and genome editing. In this report, we undertook such studies on the osteoarthritis (OA) risk that is marked by single nucleotide polymorphism (SNP) rs34195470 (A > G). The OA risk-conferring G allele of this SNP associates with increased DNA methylation (DNAm) at two CpG dinucleotides within WWP2. This gene encodes a ubiquitin ligase and is the host gene of microRNA-140 (miR-140). WWP2 and miR-140 are both regulators of TGFβ signaling. Methods Nucleic acids were extracted from adult OA (arthroplasty) and foetal cartilage. Samples were genotyped and DNAm quantified by pyrosequencing at the two CpGs plus 14 flanking CpGs. CpGs were tested for transcriptional regulatory effects using a chondrocyte cell line and reporter gene assay. DNAm was altered using epigenetic editing, with the impact on gene expression determined using RT-qPCR. In silico analysis complemented laboratory experiments. Results rs34195470 genotype associates with differential methylation at 14 of the 16 CpGs in OA cartilage, forming a methylation quantitative trait locus (mQTL). The mQTL is less pronounced in foetal cartilage (5/16 CpGs). The reporter assay revealed that the CpGs reside within a transcriptional regulator. Epigenetic editing to increase their DNAm resulted in altered expression of the full-length and N-terminal transcript isoforms of WWP2. No changes in expression were observed for the C-terminal isoform of WWP2 or for miR-140. Conclusions As far as we are aware, this is the first experimental demonstration of an OA association signal targeting specific transcript isoforms of a gene. The WWP2 isoforms encode proteins with varying substrate specificities for the components of the TGFβ signaling pathway. Future analysis should focus on the substrates regulated by the two WWP2 isoforms that are the targets of this genetic risk.

Publication metadata

Author(s): Roberts JB, Boldvig OLG, Aubourg G, Kanchenapally ST, Deehan DJ, Rice SJ, Loughlin J

Publication type: Article

Publication status: Published

Journal: Arthritis Research & Therapy

Year: 2024

Volume: 26

Online publication date: 03/04/2024

Acceptance date: 21/03/2024

Date deposited: 04/04/2024

ISSN (electronic): 1478-6362

Publisher: BioMed Central Ltd


DOI: 10.1186/s13075-024-03315-8

PubMed id: 38570801


Altmetrics provided by Altmetric


Funder referenceFunder name
20771VERSUS Arthritis (formerly Arthritis Research UK)
John George William Patterson (JGWP) Foundation
Medical Research Council
National Institute for Health Research Integrated Academic Training programme
Ruth & Lionel Jacobson Charitable Trust
Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing