title: HIV-1 Tat C phosphorylates VE-cadherin complex and increases human brain microvascular endothelial cell permeability.
abstract: BACKGROUND
  Human brain microvascular endothelial cells (hBMVECs) are integral part of the blood brain barrier. Post-translational modifications of adherens junction proteins regulate the permeability of human brain microvascular endothelial cells. Pro-inflammatory signals can induce tyrosine phosphorylation of adherens junction proteins. The primary objective of this work is to provide a molecular model; how the HIV-1 Tat protein can compromise the BBB integrity and eventually lead to neurological consequences. We exposed hBMVECs to recombinant HIV-1 clade C Tat protein to study the effect of HIV-1 Tat C on permeability of hBMVECs. Trans-endothelial electrical resistance and fluorescent dye migration assay have been used to check the permeability of hBMVECs. DCFDA staining has been used for intracellular reactive oxygen species (ROS) detection. Western blotting has been used to study the expression levels and co-immunoprecipitation has been used to study the interactions among adherens junction proteins.
  
  
  RESULTS
  HIV-1 Tat C protein induced NOX2 and NOX4 expression level and increased intracellular ROS level. Redox-sensitive kinase; PYK2 activation led to increased tyrosine phosphorylation of VE-cadherin and β-catenin, leading to disruption of junctional assembly. The dissociation of tyrosine phosphatases VE-PTP and SHP2 from cadherin complex resulted into increased tyrosine phosphorylation of VE-cadherin and β-catenin in HIV-1 Tat C treated hBMVECs.
  
  
  CONCLUSIONS
  Unrestricted phosphorylation of junctional proteins in hBMVECs, in response to HIV-1 Tat C protein; leads to the disruption of junctional complexes and increased endothelial permeability.
authors: Ritu
authors: R
authors: Mishra
authors: Laboratory of Neurovirology and Inflammation Biology, CSIR-Centre for Cellular and Molecular Biology (CCMB), Uppal Road, Hyderabad 500007, India. sunitsingh2000@gmail.com.
authors: Sunit Kumar
authors: SK
authors: Singh
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D001812:Blood-Brain Barrier / Q000378:metabolism*; D015153:Blotting, Western; D001921:Brain / Q000098:blood supply / Q000378:metabolism*; D015820:Cadherins / Q000378:metabolism*; D002199:Capillary Permeability / Q000502:physiology; D002478:Cells, Cultured; D017097:Electric Impedance; D042783:Endothelial Cells / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D005452:Fluoresceins; D005456:Fluorescent Dyes; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D047468:Immunoprecipitation; D055806:Microvessels / Q000378:metabolism*; D010766:Phosphorylation; D017382:Reactive Oxygen Species / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000378:metabolism*; D000099152:Cadherin 5
chemical_list: D015703:Antigens, CD; D015820:Cadherins; D005452:Fluoresceins; D005456:Fluorescent Dyes; D017382:Reactive Oxygen Species; D051176:beta Catenin; D054322:tat Gene Products, Human Immunodeficiency Virus; D000099152:Cadherin 5; C495270:CTNNB1 protein, human; C029569:diacetyldichlorofluorescein