Objective Tumour necrosis factor alpha (TNF-α) signalling plays a central role in the pathogenesis of various autoimmune diseases, particularly inflammatory arthritis. This study aimed to repurpose clinically approved drugs as potential inhibitors of TNF-α signalling in treatment of inflammatory arthritis.
Methods In vitro and in vivo screening of an Food and Drug Administration (FDA)-approved drug library; in vitro and in vivo assays for examining the blockade of TNF actions by fexofenadine: assays for defining the anti-inflammatory activity of fexofenadine using TNF-α transgenic (TNF-tg) mice and collagen-induced arthritis in DBA/1 mice. Identification and characterisation of the binding of fexofenadine to cytosolic phospholipase A2 (cPLA2) using drug affinity responsive target stability assay, proteomics, cellular thermal shift assay, information field dynamics and molecular dynamics; various assays for examining fexofenadine inhibition of cPLA2 as well as the dependence of fexofenadine’s anti-TNF activity on cPLA2.
Results Serial screenings of a library composed of FDA-approved drugs led to the identification of fexofenadine as an inhibitor of TNF-α signalling. Fexofenadine potently inhibited TNF/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-ĸB) signalling in vitro and in vivo, and ameliorated disease symptoms in inflammatory arthritis models. cPLA2 was isolated as a novel target of fexofenadine. Fexofenadine blocked TNF-stimulated cPLA2 activity and arachidonic acid production through binding to catalytic domain 2 of cPLA2 and inhibition of its phosphorylation on Ser-505. Further, deletion of cPLA2 abolished fexofenadine’s anti-TNF activity.
Conclusion Collectively, these findings not only provide new insights into the understanding of fexofenadine action and underlying mechanisms but also provide new therapeutic interventions for various TNF-α and cPLA2-associated pathologies and conditions, particularly inflammatory rheumatic diseases.
- inflammatory arthritis
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Handling editor Josef S Smolen
RL and YC contributed equally.
Contributors RL and YC designed and performed experiments, collected and analysed data, and cowrote the paper. YC participated in the design of the experiments and analysis of the data, particularly the identification and characterisation of the drug target. WF, SW, XZ, AH, JL, L. Zhang, CW, CZ and YB assisted with experiments, and collected and analysed data. ZL and Z-SC performed the IFD and MD simulations, and also assisted in editing the manuscript. GX assisted in analysing the data and editing the manuscript. CL designed and supervised this study, analysed data, and wrote and edited the manuscript.
Funding This work was supported partly by NIH research grants R01AR062207, R01AR061484, R01NS103931 and a DOD research grant W81XWH-16-1-0482.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval All animal studies were performed in accordance with institutional guidelines and with approval from the Institutional Animal Care and Use Committee of New York University.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement All data relevant to the study are included in the article or uploaded as supplementary information.