THU0074 ANTI-ARTHRITIC EFFECT OF RECOMBINANT CYSTATIN 3 FROM FASCIOLA HEPATICA IN COLLAGEN-INDUCED ARTHRITIS
Authors: M. Farinon, R. T. Pedo, T. Hein Da Rosa, B. Jonson Bartikoski, T. Karnopp, M. Cancela, H. Bunselmeyer Ferreira, R. Xavier
Journal: Annals of the Rheumatic Diseases (2020)

Background: Cystatins are cysteine proteases-inhibitors secreted by Fasciola hepatica in order to modulate the host immune response to promote survival of the parasite. These molecules are able to inhibit different mammal cathepsins, to regulate the immune balance via Th2 and T regulatory responses, to downregulate antigen presentation and the release of pro-inflammatory cytokines (1,2) – mechanisms that are important in the development and maintenance of several immunopathology, as rheumatoid arthritis (RA) (3). Objectives: To evaluate the therapeutic effect of recombinants cystatin 1 and cystatin 3 from Fasciola hepatica in a mice model of collagen-induced arthritis (CIA). Methods: Twenty-seven DBA/1J mice were induced with CIA by an injection of collagen type-II and Freund’s adjuvant at days 0 and 18. Animals were randomly divided into three groups: vehicle (n=9, treated with phosphate-buffered saline), cystatin 1 (n=9, treated with 100 µg/dose of recombinant cystatin 1) and cystatin 3 (n=9, treated with 100 µg/dose of recombinant cystatin 3). Treatment started after day 18 by intraperitoneal injection once a day until the end of the experiment, at day 45 after CIA induction. Clinical arthritis score, nociception, paw edema, body and spleen weight were evaluated. Lymphocytes were isolated from lymph nodes and CD4+CD25+Foxp3+ T regulatory subset was assessed by flow cytometry. Data are expressed as mean ± SEM and were evaluated by one-way or two-way ANOVA followed by Bonferroni post-test. Results: Treatment with cystatin 1 did not alter any of the analyzed parameters. On the other hand, cystatin 3 was able to reduce clinical arthritis score from day 38 with 32% of reduction at day 45 (9.22±1.22) compared to vehicle (13.56±0.73) (p&lt;0.05). In addition, treatment with cystatin 3 diminished nociception (cystatin 3: 4.0±0.36g, vehicle: 2.7±0.32g) (p&lt;0.05) and paw edema (cystatin 3: 0.051±0,012ml, vehicle: 0.093±0.007ml) (p&lt;0.05). Moreover, the treatment did not alter body weight (cystatin 3: 21.67±0.31g, vehicle: 21.05±0.38g) and spleen weight (cystatin 3: 7.04±0.31, vehicle: 7.16±0.38), as well as the T regulatory population (cystatin 3: 63.38±3.66%; vehicle: 58.31±6.77%). Conclusion: Treatment with cystatin 3 improved collagen-induced arthritis by attenuating the disease score, nociception and paw edema. Moreover, the treatment did not induce body weight loss or spleen weight alteration. These results suggest that recombinant cystatin 3 from Fasciola hepatica has the potential as a treatment for inflammatory and autoimmune diseases such as RA. References: [1]Klotz C, Ziegler T, Daniłowicz-Luebert E, Hartmann S. Cystatins of parasitic organisms. Adv Exp Med Biol. 2011;712:208-21. [2]Vray B, Hartmann S, Hoebeke J. Immunomodulatory properties of cystatins. Cell Mol Life Sci. 2002 Sep;59(9):1503-12. [3]Smolen JS, Aletaha D, McInnes IB. Rheumatoid arthritis. Lancet. 2016 Oct 22;388(10055):2023-2038. Disclosure of Interests: Mirian Farinon: None declared, Renata Ternus Pedo: None declared, Thales Hein da Rosa: None declared, Barbara Jonson Bartikoski: None declared, Thaís Karnopp: None declared, Martin Cancela: None declared, Henrique Bunselmeyer Ferreira: None declared, Ricardo Xavier Consultant of: AbbVie, Pfizer, Novartis, Janssen, Eli Lilly, Roche