title: A simple reporter assay for screening claudin-4 modulators.
abstract: Claudin-4, a member of a tetra-transmembrane protein family that comprises 27 members, is a key functional and structural component of the tight junction-seal in mucosal epithelium. Modulation of the claudin-4-barrier for drug absorption is now of research interest. Disruption of the claudin-4-seal occurs during inflammation. Therefore, claudin-4 modulators (repressors and inducers) are promising candidates for drug development. However, claudin-4 modulators have never been fully developed. Here, we attempted to design a screening system for claudin-4 modulators by using a reporter assay. We prepared a plasmid vector coding a claudin-4 promoter-driven luciferase gene and established stable reporter gene-expressing cells. We identified thiabendazole, carotene and curcumin as claudin-4 inducers, and potassium carbonate as a claudin-4 repressor by using the reporter cells. They also increased or decreased, respectively, the integrity of the tight junction-seal in Caco-2 cells. This simple reporter system will be a powerful tool for the development of claudin-4 modulators.
authors.affiliation: Laboratory of Bio-Functional Molecular Chemistry, Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Osaka 565-0871, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Watari
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Yagi
authors.forename: Masuo
authors.initials: M
authors.lastname: Kondoh
mesh_terms: D045744:Cell Line, Tumor; D062506:Claudin-4 / Q000819:agonists* / Q000037:antagonists & inhibitors*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D015870:Gene Expression / Q000187:drug effects; D017930:Genes, Reporter / Q000187:drug effects*; D006801:Humans; D008156:Luciferases / Q000235:genetics; D010957:Plasmids / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000187:drug effects
chemical_list: D062506:Claudin-4; D008156:Luciferases