title: The epithelial membrane protein 1 is a novel tight junction protein of the blood-brain barrier.
abstract: In the central nervous system, a constant microenvironment required for neuronal cell activity is maintained by the blood-brain barrier (BBB). The BBB is formed by the brain microvascular endothelial cells (BMEC), which are sealed by tight junctions (TJ). To identify genes that are differentially expressed in BMEC compared with peripheral endothelial cells, we constructed a subtractive cDNA library from porcine BMEC (pBMEC) and aortic endothelial cells (AOEC). Screening the library for differentially expressed genes yielded 26 BMEC-specific transcripts, such as solute carrier family 35 member F2 (SLC35F2), ADP-ribosylation factor-like 5B (ARL5B), TSC22 domain family member 1 (TSC22D1), integral membrane protein 2A (ITM2A), and epithelial membrane protein 1 (EMP1). In this study, we show that EMP1 transcript is enriched in pBMEC compared with brain tissue and that EMP1 protein colocalizes with the TJ protein occludin in mouse BMEC by coimmunoprecipitation and in rat brain vessels by immunohistochemistry. Epithelial membrane protein 1 expression was transiently induced in laser-capture microdissected rat brain vessels after a 20-min global cerebral ischemia, in parallel with the loss of occludin immunoreactivity. The study identifies EMP1 as a novel TJ-associated protein of the BBB and suggests its potential role in the regulation of the BBB function in cerebral ischemia.
authors.affiliation: Department of Molecular Haematology, University of Frankfurt Medical School, Frankfurt/Main, Germany. T.Bangsow@med.uni-frankfurt.de
authors.forename: Thorsten
authors.initials: T
authors.lastname: Bangsow
authors.forename: Ewa
authors.initials: E
authors.lastname: Baumann
authors.forename: Carmen
authors.initials: C
authors.lastname: Bangsow
authors.forename: Martina H
authors.initials: MH
authors.lastname: Jaeger
authors.forename: Bernhard
authors.initials: B
authors.lastname: Pelzer
authors.forename: Petra
authors.initials: P
authors.lastname: Gruhn
authors.forename: Sabine
authors.initials: S
authors.lastname: Wolf
authors.forename: Harald
authors.initials: H
authors.lastname: von Melchner
authors.forename: Danica B
authors.initials: DB
authors.lastname: Stanimirovic
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001812:Blood-Brain Barrier / Q000378:metabolism*; D002545:Brain Ischemia / Q000235:genetics / Q000378:metabolism; D002478:Cells, Cultured; D017124:Conserved Sequence; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D013552:Swine; D019108:Tight Junctions / Q000378:metabolism*
chemical_list: D009363:Neoplasm Proteins; D011956:Receptors, Cell Surface; C097051:epithelial membrane protein-1