Inflammation and dephosphorylation of the tight junction protein occludin in an experimental model of multiple sclerosis

• Published in: Neuroscience Vol. 147; no. 3; pp. 664 - 673
• Main Authors: Morgan, L, Shah, B, Rivers, L.E, Barden, L, Groom, A.J, Chung, R, Higazi, D, Desmond, H, Smith, T, Staddon, J.M
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 13-07-2007; Elsevier
• Subjects: Animals; Biological and medical sciences; blood–brain barrier; Cerebral circulation. Blood-brain barrier. Choroid plexus. Cerebrospinal fluid. Circumventricular organ. Meninges; Cerebrospinal fluid. Meninges. Spinal cord; Disease Models, Animal; EAE; edema; Electrophoresis, Gel, Two-Dimensional - methods; Encephalitis - etiology; Encephalitis - metabolism; Encephalitis - pathology; Encephalomyelitis, Autoimmune, Experimental - complications; Encephalomyelitis, Autoimmune, Experimental - metabolism; Encephalomyelitis, Autoimmune, Experimental - pathology; Endothelial Cells - cytology; experimental autoimmune encephalomyelitis; Female; Fundamental and applied biological sciences. Psychology; Immunoprecipitation - methods; kinase; Mass Spectrometry - methods; Medical sciences; Membrane Proteins - metabolism; Nervous system (semeiology, syndromes); Neurology; Occludin; Phosphoric Monoester Hydrolases - pharmacology; Phosphorylation - drug effects; Rats; Rats, Inbred Lew; signaling; Spinal Cord - pathology; Tight Junctions - metabolism; Vertebrates: nervous system and sense organs; signaling; BBB; edema; DTT; signal-transducer and activator of transcription; Laemmli sample buffer; LRP; phosphate-buffered saline; lung-resistance protein; blood–brain barrier; experimental autoimmune encephalomyelitis; days post-immunization; immunoprecipitation; Glut-1; LSB; MBP; sodium dodecyl sulfate–polyacrylamide gel electrophoresis; PBS; RSA; dithiothreitol; MALDI; MS; multiple sclerosis; IP; rat serum albumin; EAE; interferon-γ-induced GTPase; myelin basic protein; SDS-PAGE; kinase; STAT; matrix-assisted laser desorption/ionization; d.p.i; IGTP; glucose transporter-1; blood-brain barrier; Nervous system diseases; Encephalomyelitis; Enzyme; Transferases; Central nervous system; Cell junction; Inflammation; Dephosphorylation; Blood brain barrier; Protein; Cerebral disorder; Signal transduction; Kinase; Central nervous system disease; Tight junction; Models; Spinal cord disease
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2007.04.051

Abstract Multiple sclerosis (MS) is a disease of the CNS in which inflammation, demyelination and neurodegeneration contribute to its initiation and progression. A frequently employed model of MS is experimental autoimmune encephalomyelitis (EAE). Here, to gain new insights into the disease process, an analysis of proteins in extracts of lumbar spinal cord from naïve and EAE rats was undertaken. The data mainly confirm that inflammation and blood–brain barrier (BBB) breakdown are the major hallmarks of disease in this model. Given their importance in the BBB, junctional proteins were further investigated. Occludin, a protein localizing to tight junctions in brain endothelial cells, showed strikingly increased migration in EAE when analyzed by sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE). This increased migration was mimicked by in vitro phosphatase treatment, implying its dephosphorylation in EAE. Occludin dephosphorylation coincided with the onset of inflammation, slightly preceding visible signs of disease, and was just prior to apparent changes in BBB permeability. These findings suggest occludin is a target for signaling processes in EAE, perhaps regulating the response of the BBB to the inflammatory environment as seen in MS.