title: Clausmarin A, Potential Immunosuppressant Revealed by Yeast-Based Assay and Interleukin-2 Production Assay in Jurkat T Cells.
abstract: Small-molecule inhibitors of Ca2+-signaling pathways are of medicinal importance, as exemplified by the immunosuppressants FK506 and cyclosporin A. Using a yeast-based assay devised for the specific detection of Ca2+-signaling inhibitors, clausmarin A, a previously reported terpenoid coumarin, was identified as an active substance. Here, we investigated the likely mechanism of clausmarin A action in yeast and Jurkat T-cells. In the presence of 100 mM CaCl2 in the growth medium of Ca2+-sensitive Δzds1 strain yeast, clausmarin A exhibited a dose-dependent alleviation of various defects due to hyperactivation of Ca2+ signaling, such as growth inhibition, polarized bud growth and G2 phase cell-cycle arrest. Furthermore, clausmarin A inhibited the growth of Δmpk1 (lacking the Mpk1 MAP kinase pathway) but not Δcnb1 (lacking the calcineurin pathway) strain, suggesting that clausmarin A inhibited the calcineurin pathway as presumed from the synthetic lethality of these pathways. Furthermore, clausmarin A alleviated the serious defects of a strain expressing a constitutively active form of calcineurin. In the human Jurkat T-cell line, clausmarin A exhibited a dose-dependent inhibition of IL-2 production and IL-2 gene transcription, as well as an inhibition of NFAT dephosphorylation. The effects of clausmarin A observed in both yeast and Jurkat cells are basically similar to those of FK506. Our study revealed that clausmarin A is an inhibitor of the calcineurin pathway, and that this is probably mediated via inhibition of calcineurin phosphatase activity. As such, clausmarin A is a potential immunosuppressant.
authors: Department of Microbiology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand.
authors: Pitipreya
authors: P
authors: Suauam
authors: Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Ramkhamhaeng University, Ramkhamhaeng Road, Hua Mark, Bangkapi, Bangkok, 10240, Thailand.
authors: Boon-Ek
authors: BE
authors: Yingyongnarongkul
authors: Department of Microbiology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand.
authors: Tanapat
authors: T
authors: Palaga
authors: Department of Molecular Biotechnology, Graduate School of Advanced Sciences of Matter, Hiroshima University, Higashihiroshima, 739-8530, Japan.
authors: Tokichi
authors: T
authors: Miyakawa
authors: Department of Microbiology, Faculty of Science, Chulalongkorn University, Phayathai Road, Pathumwan, Bangkok, 10330, Thailand.
authors: Chulee
authors: C
authors: Yompakdee
mesh_terms: D002118:Calcium / Q000378:metabolism; D003374:Coumarins / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006801:Humans; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D007376:Interleukin-2 / Q000235:genetics / Q000378:metabolism*; D019169:Jurkat Cells / Q000187:drug effects / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D050778:NFATC Transcription Factors / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D003374:Coumarins; D007166:Immunosuppressive Agents; D007376:Interleukin-2; D050778:NFATC Transcription Factors; D029701:Saccharomyces cerevisiae Proteins; C035875:clausmarin; D020928:Mitogen-Activated Protein Kinases; C072724:SLT2 protein, S cerevisiae; D002118:Calcium