title: Lapachol, a compound targeting pyrimidine metabolism, ameliorates experimental autoimmune arthritis.
abstract: The inhibition of pyrimidine biosynthesis by blocking the dihydroorotate dehydrogenase (DHODH) activity, the prime target of leflunomide (LEF), has been proven to be an effective strategy for rheumatoid arthritis (RA) treatment. However, a considerable proportion of RA patients are refractory to LEF. Here, we investigated lapachol (LAP), a natural naphthoquinone, as a potential DHODH inhibitor and addressed its immunosuppressive properties.
  
  
  
  Molecular flexible docking studies and bioactivity assays were performed to determine the ability of LAP to interact and inhibit DHODH. In vitro studies were conducted to assess the antiproliferative effect of LAP using isolated lymphocytes. Finally, collagen-induced arthritis (CIA) and antigen-induced arthritis (AIA) models were employed to address the anti-arthritic effects of LAP.
  
  
  
  We found that LAP is a potent DHODH inhibitor which had a remarkable ability to inhibit both human and murine lymphocyte proliferation in vitro. Importantly, uridine supplementation abrogated the antiproliferative effect of LAP, supporting that the pyrimidine metabolic pathway is the target of LAP. In vivo, LAP treatment markedly reduced CIA and AIA progression as evidenced by the reduction in clinical score, articular tissue damage, and inflammation.
  
  
  
  Our findings propose a binding model of interaction and support the ability of LAP to inhibit DHODH, decreasing lymphocyte proliferation and attenuating the severity of experimental autoimmune arthritis. Therefore, LAP could be considered as a potential immunosuppressive lead candidate with potential therapeutic implications for RA.
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, Center of Research in Inflammatory Diseases (CRID), University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo, CEP: 14049-900, Brazil.
authors.forename: Raphael S
authors.initials: RS
authors.lastname: Peres
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, CEP: 14040-903, Brazil.
authors.forename: Gabriela B
authors.initials: GB
authors.lastname: Santos
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, Center of Research in Inflammatory Diseases (CRID), University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo, CEP: 14049-900, Brazil.
authors.forename: Nerry T
authors.initials: NT
authors.lastname: Cecilio
authors.affiliation: NPPNS, Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, Brazil.
authors.forename: Valquíria A P
authors.initials: VA
authors.lastname: Jabor
authors.affiliation: NPPNS, Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, Brazil.
authors.forename: Michael
authors.initials: M
authors.lastname: Niehues
authors.affiliation: Pharmaceutical Sciences Graduate Program, Faculty of Pharmacy, Federal University of Rio Grande do Sul, Sarmento Leite 521, Porto Alegre, Brazil.
authors.forename: Bruna G S
authors.initials: BG
authors.lastname: Torres
authors.affiliation: NPPNS, Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, Brazil.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Buqui
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, CEP: 14040-903, Brazil.
authors.forename: Carlos H T P
authors.initials: CH
authors.lastname: Silva
authors.affiliation: Pharmaceutical Sciences Graduate Program, Faculty of Pharmacy, Federal University of Rio Grande do Sul, Sarmento Leite 521, Porto Alegre, Brazil.
authors.forename: Teresa Dalla
authors.initials: TD
authors.lastname: Costa
authors.affiliation: NPPNS, Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, Brazil.
authors.forename: Norberto P
authors.initials: NP
authors.lastname: Lopes
authors.affiliation: NPPNS, Department of Physics and Chemistry, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, Brazil.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Nonato
authors.affiliation: Department of Pathology, Ribeirão Preto Medical School, University of São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, Brazil.
authors.forename: Fernando S
authors.initials: FS
authors.lastname: Ramalho
authors.affiliation: Department of Internal Medicine, Ribeirão Preto Medical School, Center of Research in Inflammatory Diseases (CRID), University of São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: Louzada-Júnior
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, Center of Research in Inflammatory Diseases (CRID), University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo, CEP: 14049-900, Brazil.
authors.forename: Thiago M
authors.initials: TM
authors.lastname: Cunha
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, Center of Research in Inflammatory Diseases (CRID), University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo, CEP: 14049-900, Brazil.
authors.forename: Fernando Q
authors.initials: FQ
authors.lastname: Cunha
authors.affiliation: Department of Pharmaceutical Sciences, Faculty of Pharmaceutical Sciences of Ribeirão Preto, University of São Paulo, Avenida do Café s/n, Ribeirão Preto, CEP: 14040-903, Brazil. flavioemery@fcfrp.usp.br.
authors.forename: Flavio S
authors.initials: FS
authors.lastname: Emery
authors.affiliation: Department of Pharmacology, Ribeirão Preto Medical School, Center of Research in Inflammatory Diseases (CRID), University of São Paulo, Avenida Bandeirantes, 3900, Ribeirão Preto, São Paulo, CEP: 14049-900, Brazil. jcafilho@usp.br.
authors.forename: Jose C
authors.initials: JC
authors.lastname: Alves-Filho
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000188:drug therapy*; D001172:Arthritis, Rheumatoid / Q000188:drug therapy*; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D000090722:Dihydroorotate Dehydrogenase; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D008213:Lymphocyte Activation / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D062105:Molecular Docking Simulation; D009285:Naphthoquinones / Q000494:pharmacology*; D044925:Oxidoreductases Acting on CH-CH Group Donors / Q000037:antagonists & inhibitors; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000090722:Dihydroorotate Dehydrogenase; D007166:Immunosuppressive Agents; D009285:Naphthoquinones; C008252:lapachol; D044925:Oxidoreductases Acting on CH-CH Group Donors
keywords: Collagen-induced arthritis; DMARDs; Dihydroorotate dehydrogenase; Inflammation; Lapachol; Pyrimidine metabolism; Rheumatoid arthritis