title: β-Catenin Is Required for Endothelial Cyp1b1 Regulation Influencing Metabolic Barrier Function.
abstract: The canonical Wnt/β-catenin signaling pathway is crucial for blood-brain barrier (BBB) formation in brain endothelial cells. Although glucose transporter 1, claudin-3, and plasmalemma vesicular-associated protein have been identified as Wnt/β-catenin targets in brain endothelial cells, further downstream targets relevant to BBB formation and function are incompletely explored. By Affymetrix expression analysis, we show that the cytochrome P450 enzyme Cyp1b1 was significantly decreased in β-catenin-deficient mouse endothelial cells, whereas its close homolog Cyp1a1 was upregulated in an aryl hydrocarbon receptor-dependent manner, hence indicating that β-catenin is indispensable for Cyp1b1 but not for Cyp1a1 expression. Functionally, Cyp1b1 could generate retinoic acid from retinol leading to cell-autonomous induction of the barrier-related ATP-binding cassette transporter P-glycoprotein. Cyp1b1 could also generate 20-hydroxyeicosatetraenoic acid from arachidonic acid, decreasing endothelial barrier function in vitro In mice in vivo pharmacological inhibition of Cyp1b1 increased BBB permeability for small molecular tracers, and Cyp1b1 was downregulated in glioma vessels in which BBB function is lost. Hence, we propose Cyp1b1 as a target of β-catenin indirectly influencing BBB properties via its metabolic activity, and as a potential target for modulating barrier function in endothelial cells.
  
  
  
  Wnt/β-catenin signaling is crucial for blood-brain barrier (BBB) development and maintenance; however, its role in regulating metabolic characteristics of endothelial cells is unclear. We provide evidence that β-catenin influences endothelial metabolism by transcriptionally regulating the cytochrome P450 enzyme Cyp1b1 Furthermore, expression of its close homolog Cyp1a1 was inhibited by β-catenin. Functionally, Cyp1b1 generated retinoic acid as well as 20-hydroxyeicosatetraenoic acid that regulated P-glycoprotein and junction proteins, respectively, thereby modulating BBB properties. Inhibition of Cyp1b1 in vivo increased BBB permeability being in line with its downregulation in glioma endothelia, potentially implicating Cyp1b1 in other brain pathologies. In conclusion, Wnt/β-catenin signaling regulates endothelial metabolic barrier function through Cyp1b1 transcription.
authors: Institute of Neurology (Edinger-Institute), Goethe-University Frankfurt Medical School, 60528 Frankfurt, Germany.
authors: Nicole
authors: N
authors: Ziegler
authors: Institute for Vascular Signaling, Goethe University, 60596 Frankfurt, Germany.
authors: Khader
authors: K
authors: Awwad
authors: Institute for Vascular Signaling, Goethe University, 60596 Frankfurt, Germany, German Center for Cardiovascular Research, Partner Site Rhine-Main, 60528 Frankfurt, Germany.
authors: Beate
authors: B
authors: Fisslthaler
authors: Roche Innovation Center Penzberg, Pharma Research and Early Development, Oncology, Roche Diagnostics GmbH, 82377 Penzberg, Germany.
authors: Marco
authors: M
authors: Reis
authors: Institute of Neurology (Edinger-Institute), Goethe-University Frankfurt Medical School, 60528 Frankfurt, Germany.
authors: Kavi
authors: K
authors: Devraj
authors: FIRC Institute of Molecular Oncology, 20139 Milan, Italy.
authors: Monica
authors: 0000-0001-8220-0871
authors: M
authors: Corada
authors: FIRC Institute of Molecular Oncology, 20139 Milan, Italy.
authors: Simone Paolo
authors: 0000-0001-7303-3821
authors: SP
authors: Minardi
authors: FIRC Institute of Molecular Oncology, 20139 Milan, Italy, Department of Immunology, Genetic and Pathology, University of Uppsala, 75105 Uppsala, Sweden, and Dipartimento di Bioscienze, University of Milan, 20133 Milan, Italy.
authors: Elisabetta
authors: 0000-0002-0007-0426
authors: E
authors: Dejana
authors: Institute of Neurology (Edinger-Institute), Goethe-University Frankfurt Medical School, 60528 Frankfurt, Germany, German Center for Cardiovascular Research, Partner Site Rhine-Main, 60528 Frankfurt, Germany.
authors: Karl H
authors: KH
authors: Plate
authors: Institute for Vascular Signaling, Goethe University, 60596 Frankfurt, Germany, German Center for Cardiovascular Research, Partner Site Rhine-Main, 60528 Frankfurt, Germany.
authors: Ingrid
authors: 0000-0003-1881-3635
authors: I
authors: Fleming
authors: Institute of Neurology (Edinger-Institute), Goethe-University Frankfurt Medical School, 60528 Frankfurt, Germany, German Center for Cardiovascular Research, Partner Site Rhine-Main, 60528 Frankfurt, Germany, stefan.liebner@kgu.de.
authors: Stefan
authors: 0000-0002-4656-2258
authors: S
authors: Liebner
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000378:metabolism*; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D002199:Capillary Permeability / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D065633:Cytochrome P-450 CYP1B1 / Q000235:genetics / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics / Q000502:physiology*; D005910:Glioma / Q000378:metabolism / Q000473:pathology; D006657:Histones / Q000378:metabolism; D006893:Hydroxyeicosatetraenoic Acids / Q000494:pharmacology; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008954:Models, Biological; D009368:Neoplasm Transplantation; D012333:RNA, Messenger / Q000378:metabolism; D018336:Receptors, Aryl Hydrocarbon / Q000235:genetics / Q000378:metabolism; D060449:Wnt Signaling Pathway / Q000235:genetics / Q000502:physiology*; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D015820:Cadherins; D065633:Cytochrome P-450 CYP1B1; D006657:Histones; D006893:Hydroxyeicosatetraenoic Acids; D012333:RNA, Messenger; D018336:Receptors, Aryl Hydrocarbon; D051176:beta Catenin; C484722:Ahr protein, mouse; C055987:20-hydroxy-5,8,11,14-eicosatetraenoic acid; C585496:CYP1B1 protein, human
keywords: Cyp1b1; Wnt signaling; cytochrome P450; glioma; transcriptional regulation; β-catenin