title: Identification of small-molecule inhibitors of calcineurin-NFATc signaling that mimic the PxIxIT motif of calcineurin binding partners.
abstract: Calcineurin (CN), a serine and threonine protein phosphatase that depends on Ca(2+) and calmodulin for its activity, is the target of the immunosuppressant drugs cyclosporin A (CsA) and tacrolimus (FK506). CN dephosphorylates and activates members of the NFATc (nuclear factor of activated T cells) family of transcription factors in T cells by binding to their conserved PxIxIT motif. Upon dephosphorylation, NFATc proteins translocate to the nucleus, where they stimulate the expression of genes encoding cytokines and chemokines that are required for T cell proliferation and the immune response. We performed a pharmacophore-based virtual screening of ~5.5 million commercially available, "drug-like" compounds to identify nonpeptidic compounds that inhibited the CN-dependent activation of NFATc signaling and that could serve as potential drug candidates for immunosuppressive therapy. Of 32 compounds that mimicked the PxIxIT motif, 7 competed with NFATc for binding to CN in vitro without interfering with the phosphatase activity of CN. Furthermore, in activated human CD4(+) T cells, four of the seven compounds inhibited the expression of NFATc-dependent genes, cytokine production, and cell proliferation, suggesting that these may have therapeutic potential as immunosuppressive agents.
authors.affiliation: Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: Minos-Timotheos
authors.initials: MT
authors.lastname: Matsoukas
authors.affiliation: Cellular Signalling Group, Laboratori de Genètica Molecular, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Spain.
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Aranguren-Ibáñez
authors.affiliation: Programa de Inmunología e Inmunoterapia, Centro de Investigación Médica Aplicada - CIMA, Universidad de Navarra, IDISNA, Instituto de Investigación Sanitaria de Navarra, Navarra, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Lozano
authors.affiliation: Laboratori de Genètica Molecular, IDIBELL, U-730, Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), and Departament de Ciències Fisiològiques II, Facultat de Medicina, Universitat de Barcelona, 08908 Hospitalet del Llobregat, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Nunes
authors.affiliation: Programa de Inmunología e Inmunoterapia, Centro de Investigación Médica Aplicada - CIMA, Universidad de Navarra, IDISNA, Instituto de Investigación Sanitaria de Navarra, Navarra, Spain.
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Lasarte
authors.affiliation: Laboratori de Medicina Computacional, Unitat de Bioestadística, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain. leonardo.pardo@uab.es mpr@idibell.cat.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Pardo
authors.affiliation: Cellular Signalling Group, Laboratori de Genètica Molecular, Bellvitge Biomedical Research Institute (IDIBELL), 08908 L'Hospitalet de Llobregat, Spain. leonardo.pardo@uab.es mpr@idibell.cat.
authors.forename: Mercè
authors.initials: M
authors.lastname: Pérez-Riba
mesh_terms: D020816:Amino Acid Motifs; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D019703:Calcineurin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D065095:Calcineurin Inhibitors / Q000737:chemistry / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D050778:NFATC Transcription Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
chemical_list: D065095:Calcineurin Inhibitors; D050778:NFATC Transcription Factors; C494003:NFATC1 protein, human; D019703:Calcineurin