DNA methylation analysis of synovial fibroblasts from mice undergoing collagen-induced arthritis (CIA) treated, or not, with the the helminth-derived immunomodulator, ES-62

Aim: Synovial fibroblasts (SFs) undergo a rewiring of their DNA methylation landscape that is associated with their development of an aggressive pathogenic phenotype during Rheumatoid Arthritis (RA), both in humans and in CIA, a mouse model of this chronic inflammatory disease. The helminth-derived immunomodulator, ES-62 acts to prevent joint destruction in CIA by suppressing pathogenic SF responses. We therefore investigated whether ES-62 suppressed the changes in DNA methylation observed in SFs from CIA, relative to those from healthy, mice. Methods: The DNA methylation status of SFs from naïve (no induction of CIA), CIA and ES-62-treated mice undergoing CIA (CIA_ES-62) was compared by Reduced Representation Bilsulphite Sequencing (RRBS) analysis performed by the Active Motif service. Results: Synovial fibroblasts from naive, CIA and CIA_ES-62 mice exhibit differential genomic methylation profiles. Conclusion: ES-62 protection against joint protection in CIA is not associated with prevention of the changes in DNA methylation occurring during rewiring of naive SFs to aggressively pathogenic CIA SFs but rather, reflects generation of a distinct ES-62 phenotype of SF genomic methylation. Overall design: Comparison of the genomic methylation profiles of SFs from naïve, CIA and ES-62-treated CIA mice.