POS0107 IDENTIFICATION OF POTENTIAL GENES AND TREATMENT RESPONSE TO TOFACITINIB THERAPY IN PATIENTS WITH RHEUMATOID ARTHRITIS
Authors: S. Janahiraman, C. L. Too, S. S. Ch’ng, L. H. Eow, E. Mageswaren, A. L. Lim, H. C. Chong, P. S. Ong, A. Mohamed Ismail, S. M. Abd Rahim, C. R. Ng, D. M. Suahilai, A. H. Ramlan, N. S. Shahril, C. O. Leong
Journal: Annals of the Rheumatic Diseases (2024)

<h3>Background:</h3> Tofacitinib is the first oral targeted synthetic disease-modifying anti-rheumatic drug (DMARD) for rheumatoid arthritis (RA) treatment resistant to the conventional synthetic DMARD. Currently, very little is known about the genetic predictors to determine the treatment response of targeted synthetic DMARDs albeit earlier identification may lead to a stratified treatment. <h3>Objectives:</h3> To identify potential genes for treatment response of tofacitinib in patients with rheumatoid arthritis. <h3>Methods:</h3> We conducted the first comprehensive whole genome sequencing (WGS) study in a total of 58 RA patients categorised according to tofacitinib response based on DAS28-ESR/CRP score after 6 months of therapy (i.e. 29 responders and 29 non-responders). Variant Call Format files were annotated and filtered following primary and secondary analysis. Single-nucleotide variants (SNV) and short insertions/deletions (Indels) were identified. All coding variants for both responders and non-responders were considered for pathway enrichment analysis using Kyoto Encyclopedia of Genes and Genomes (KEGG). Next, the STRING database was utilized to construct protein-protein interaction (PPI) network and to identify the most-interacting genes among them, top 10 hub genes for both responders and non-responders were determined by employing Cytohubba module of Cytoscape. Furthermore, the identified sub-networks among hub genes, comprising 5 genes for both responders and non-responders, were subjected to structural modelling and molecular docking techniques to explore the impact of identified mutations on their functions. <h3>Results:</h3> We identified a total of 3183 coding variants among tofacitinib non-responders. The KEGG pathway analysis revealed 50 genes enriched in synaptic vesicle cycle, olfactory transduction, ABC transporters, fatty acid elongation, ether lipid metabolism, sphingolipid metabolism, galactose metabolism and complement and coagulation cascade pathways. Of these, 47 genes (94%) were found to significantly interact with other genes (p&lt;0.05, FDR&lt;0.05). The top 10 identified hub genes in non-responders were mainly involved in RA pathogenesis pathways such as modulation of immune system (MGAM2, NEU4), inflammatory responses (GLB1, PLA2G7, PLA2G4F), lipid and glucose metabolism (UGT8, ABCA6, LCT) and complement system (CR1, CR2) leading to activation of innate and adaptive immunity. Meanwhile, the 8 genes identified among responders were related to immunoregulation (PIK3R2, INSR, PRKCA) and inflammatory process (PIK3R2, INSR, PRKCA, FN1,HEXB, HEXD and LAMA5). The structural modelling and molecular docking analysis on wild and mutant structures of the sub-network of hub genes for both responders and non-responders revealed that mutant proteins (NEU4, UGT8, MGAM2, and GLB1) in non-responders observed to have better docking scores with their functional partners as compared to wild proteins that may have led to increased inflammation and dysregulated immune response. <h3>Conclusion:</h3> Our study has shed light on the potential role of genomic alterations on the response of tofacitinib, paving way to devise novel therapeutic strategies to overcome tofacitinib treatment inefficacy in RA patients. <h3>REFERENCES:</h3> [1] Valli A, Kuuliala K, Virtanen A, Kuuliala A, Palmroth M, Peltomaa R, Vidqvist KL, Leirisalo-Repo M, Silvennoinen O, Isomäki P. Tofacitinib treatment modulates the levels of several inflammation-related plasma proteins in rheumatoid arthritis and baseline levels of soluble biomarkers associate with the treatment response. Clin Exp Immunol. 2022 Dec 15;210(2):141-150. doi: 10.1093/cei/uxac085. PMID: 36124688; PMCID: PMC9750823. [2] Kerekes G, Czókolyová M, Hamar A, Pusztai A, Tajti G, Katkó M, Végh E, Pethő Z, Bodnár N, Horváth Á, Soós B, Szamosi S, Hascsi Z, Harangi M, Hodosi K, Panyi G, Seres T, Szűcs G, Szekanecz Z. Effects of 1-year tofacitinib therapy on angiogenic biomarkers in rheumatoid arthritis. Rheumatology (Oxford). 2023 Oct 23;62(SI3):SI304-SI312. doi: 10.1093/rheumatology/kead502. PMID: 37871914; PMCID: PMC10593522. <h3>Acknowledgements:</h3> Special thanks to Director General of Health Malaysia for his permission to present this article and International Medical University Research Grant [PHMS I-2021 (04)] for financial support. <h3>Disclosure of Interests:</h3> <b>None declared.</b>