title: Reciprocal regulation of the junctional proteins claudin-1 and connexin43 by interleukin-1beta in primary human fetal astrocytes.
abstract: Vertebrate tissues use multiple junctional types to establish and maintain tissue architecture, including gap junctions for cytoplasmic connectivity and tight junctions (TJs) for paracellular and/or cell polarity barriers. The integral membrane proteins of gap junctions are connexins, whereas TJs are a complex between occludin and members of a recently characterized multigene family, the claudins. In normal brain, astrocytes are coupled by gap junctions composed primarily of connexin43 (Cx43), whereas TJs have not been detected in these cells. We now show that treatment of primary human astrocytes with the cytokine interleukin-1beta (IL-1beta) causes rapid induction of claudin-1, with an expression pattern reciprocal to loss of Cx43. Treatment also led to protracted downregulation of occludin but no change in expression of zonula occludens proteins ZO-1 and -2. Immunofluorescence staining localized claudin-1 to cell membranes in IL-1beta-treated astrocytes, whereas freeze-fracture replicas showed strand-like arrays of intramembranous particles in treated cells resembling rudimentary TJ assemblies. We conclude that in human astrocytes, IL-1beta regulates expression of the claudin multigene family and that gap and tight junction proteins are inversely regulated by this proinflammatory cytokine. We suggest that in pathological conditions of the human CNS, elevated IL-1beta expression fundamentally alters astrocyte-to-astrocyte connectivity.
authors.affiliation: Departments of Neuroscience and Pathology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: H S
authors.initials: HS
authors.lastname: Duffy
authors.forename: G R
authors.initials: GR
authors.lastname: John
authors.forename: S C
authors.initials: SC
authors.lastname: Lee
authors.forename: C F
authors.initials: CF
authors.lastname: Brosnan
authors.forename: D C
authors.initials: DC
authors.lastname: Spray
mesh_terms: D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000196:embryology / Q000378:metabolism; D062445:Claudin-1; D018031:Connexin 43 / Q000378:metabolism*; D017630:Connexins / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D005614:Freeze Fracturing; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1 / Q000378:metabolism* / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D062793:Occludin; D010750:Phosphoproteins / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis; D017472:Receptors, Interleukin-1 / Q000378:metabolism; D012795:Sialoglycoproteins / Q000378:metabolism / Q000494:pharmacology; D062825:Zonula Occludens Proteins; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein
chemical_list: C568108:CLDN1 protein, human; D002352:Carrier Proteins; D062445:Claudin-1; D018031:Connexin 43; D017630:Connexins; C507763:IL1RN protein, human; D053590:Interleukin 1 Receptor Antagonist Protein; D007375:Interleukin-1; D008565:Membrane Proteins; C568985:OCLN protein, human; D062793:Occludin; D010750:Phosphoproteins; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D012795:Sialoglycoproteins; C569042:TJP1 protein, human; C569046:TJP2 protein, human; C111873:TJP3 protein, human; D062825:Zonula Occludens Proteins; D062826:Zonula Occludens-1 Protein; D062827:Zonula Occludens-2 Protein