Ab0731 in-Vitro Drug Screening Reveals the Potential of Epigenetic Compounds for the Treatment of Rheumatoid Arthritis

Background: While the precise mechanisms underlying Rheumatoid Arthritis (RA) remain not fully understood, it is apparent that a complex interplay of genetic and environmental factors significantly contributes to its pathogenesis (1). Epigenetics acts as a mediator linking environmental influences to disease onset and further directs pathogenic activation of immune cells (2). Consequently, compounds that target proteins engaged in chromatin modification emerge as promising candidates for epigenetic therapeutic interventions in autoimmune diseases. Objectives: This study aims to provide experimental evidence for the potential of epigenetic drugs as a novel treatment approach for RA patients. Methods: PBMCs from healthy donors and RA patients were activated with Phytohemagglutinin (PHA) and treated for 24 hours with epigenetic inhibitors. Drug effects were analysed utilising spectral cytometry (Cytek Aurora), enabling the discrimination of 26 cell types and 11 comprehensive activation markers. In addition, we employed bulk RNA sequencing to inspect compound-induced alterations at the transcriptional level. A bioinformatics pipeline was established, including quality control, dimensionality reduction methods, and multi-parameter analysis, allowing the integration of data on the cellular and transcriptional levels. Results: Twenty-six potential drugs were screened and characterized, demonstrating their potential as novel treatment approaches for RA. Flow cytometry revealed compound-specific effects on the cell subset distribution and activation status of PBMC subsets. A clustering of the tested epigenetic compounds was consistently found in both flow cytometry and RNA sequencing data, indicating compound-target-specific modes of action. Enrichment analysis unveiled the association of compound-affected genes with immunological processes, cytokine signalling, and genes involved in autoimmune diseases like RA. This suggests anti-inflammatory and potential therapeutic characteristics of epigenetic drugs. Conclusion: We established a high-throughput drug screening tool to characterize compound-specific effects that might predict treatment responses and underlying mechanisms. We could indeed provide evidence of potential therapeutic mechanisms, proving the remarkable potential of epigenetic inhibitors as a novel treatment approach for RA. REFERENCES: [1] Nemtsova MV, Zaletaev DV, Bure IV, Mikhaylenko DS, Kuznetsova EB, Alekseeva EA, et al. Epigenetic Changes in the Pathogenesis of Rheumatoid Arthritis. Front Genet. 2019;10:570. [2] Klein K, Gay S. Epigenetics in rheumatoid arthritis. Curr Opin Rheumatol. 2015;27(1):76-82. Acknowledgements: NIL. Disclosure of Interests: Marie Brinkmann: None declared, Teresa Preglej: None declared, Anela Tosevska: None declared, Bianca Luckerbauer: None declared, Günter Steiner: None declared, Daniel Aletaha reports about grants from Abbvie, Amgen, Galapagos, Lilly, and Sanofi; consulting fees and speakers' bureau from Abbvie, Amgen, Galapagos, Lilly, Janssen, Merck, Novartis, Pfizer, and Sandoz, Lisa Göschl: None declared, Michael Bonelli received grants from Galapagos and GSK.