title: The retinoic acid receptor-related orphan receptor α positively regulates tight junction protein claudin domain-containing 1 mRNA expression in human brain endothelial cells.
abstract: Members of the claudin family play important roles in the formation of tight junctions (TJs) in several tissues. Claudin domain containing 1 (CLDND1) is homologous to this family and localizes to TJs and the cytoplasm when exogenously expressed in cultured epithelial cell lines. Furthermore, serum antibody levels of CLDND1-derived peptides are elevated in patients with cerebral infection, cardiovascular disease or diabetes mellitus as compared to healthy controls. However, CLDND1 transcriptional regulation remains poorly analyzed and most regional transcription factor binding sites remain to be defined. Notably, the CLDND1 promoter contains a putative response element for retinoic acid receptor-related orphan receptor α (RORα), which is involved in the above-mentioned disorders. In this study, we found that Cldnd1 and Rora mRNA levels are correlated in rat tissues and that RORα overexpression in human brain endothelial cells enhanced CLDND1 transcript expression. In addition, siRNA-mediated knockdown of RORα significantly decreased CLDND1 transcription. An electrophoresis mobility shift assay indicated that RORα binds to the identified response element in a sequence-specific manner. Furthermore, luciferase reporter assays confirmed that RORα interacts with the CLDND1 promoter to enhance transcription. Taken together, our findings strongly suggest that CLDND1 is a direct RORα target.
authors.affiliation: Laboratory of Genome Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuoka
authors.affiliation: Laboratory of Genome Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
authors.forename: Akiho
authors.initials: A
authors.lastname: Shima
authors.affiliation: Laboratory of Genome Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
authors.forename: Arisa
authors.initials: A
authors.lastname: Uda
authors.affiliation: Laboratory of Genome Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Ezaki
authors.affiliation: Laboratory of Genome Function and Pathophysiology, Faculty of Pharmacy and Pharmaceutical Sciences, Fukuyama University, Fukuyama, Hiroshima 729-0292, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Michihara
mesh_terms: D000818:Animals; D001921:Brain / Q000166:cytology*; D002478:Cells, Cultured; D057167:Claudins / Q000235:genetics*; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D020869:Gene Expression Profiling; D006801:Humans; D008297:Male; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1 / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics*; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: C462524:CLDND1 protein, human; D057167:Claudins; D057094:Nuclear Receptor Subfamily 1, Group F, Member 1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C539738:RORA protein, human
keywords: CLDND1; RORα; brain endothelium; tight junction; transcriptional regulation