title: HIV-1 induces cytoskeletal alterations and Rac1 activation during monocyte-blood-brain barrier interactions: modulatory role of CCR5.
abstract: BACKGROUND
  Most HIV strains that enter the brain are macrophage-tropic and use the CCR5 receptor to bind and infect target cells. Because the cytoskeleton is a network of protein filaments involved in cellular movement and migration, we investigated whether CCR5 and the cytoskeleton are involved in endothelial-mononuclear phagocytes interactions, adhesion, and HIV-1 infection.
  
  
  RESULTS
  Using a cytoskeleton phospho-antibody microarray, we showed that after co-culture with human brain microvascular endothelial cells (HBMEC), HIV-1 infected monocytes increased expression and activation of cytoskeleton-associated proteins, including Rac1/cdc42 and cortactin, compared to non-infected monocytes co-cultured with HBMEC. Analysis of brain tissues from HIV-1-infected patients validated these findings, and showed transcriptional upregulation of Rac1 and cortactin, as well as increased activation of Rac1 in brain tissues of HIV-1-infected humans, compared to seronegative individuals and subjects with HIV-1-encephalitis. Confocal imaging showed that brain cells expressing phosphorylated Rac1 were mostly macrophages and blood vessels. CCR5 antagonists TAK-799 and maraviroc prevented HIV-induced upregulation and phosphorylation of cytoskeleton-associated proteins, prevented HIV-1 infection of macrophages, and diminished viral-induced adhesion of monocytes to HBMEC. Ingenuity pathway analysis suggests that during monocyte-endothelial interactions, HIV-1 alters protein expression and phosphorylation associated with integrin signaling, cellular morphology and cell movement, cellular assembly and organization, and post-translational modifications in monocytes. CCR5 antagonists prevented these HIV-1-induced alterations.
  
  
  CONCLUSIONS
  HIV-1 activates cytoskeletal proteins during monocyte-endothelial interactions and increase transcription and activation of Rac1 in brain tissues. In addition to preventing macrophage infection, CCR5 antagonists could diminish viral-induced alteration and phosphorylation of cytoskeletal proteins, monocyte adhesion to the brain endothelium and viral entry into the central nervous system.
authors.forename: Shawna M
authors.initials: SM
authors.lastname: Woollard
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.forename: Sangya
authors.initials: S
authors.lastname: Singh
authors.forename: Fang
authors.initials: F
authors.lastname: Yu
authors.affiliation: Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska 68198-5800, USA. gkanmogne@unmc.edu.
authors.forename: Georgette D
authors.initials: GD
authors.lastname: Kanmogne
mesh_terms: D000328:Adult; D000368:Aged; D001812:Blood-Brain Barrier; D002448:Cell Adhesion; D003599:Cytoskeleton / Q000378:metabolism*; D042783:Endothelial Cells / Q000502:physiology; D005260:Female; D015497:HIV-1 / Q000502:physiology*; D054884:Host-Pathogen Interactions; D006801:Humans; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000502:physiology / Q000821:virology*; D019713:Receptors, CCR5 / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein / Q000378:metabolism*
chemical_list: C584933:CCR5 protein, human; C107953:RAC1 protein, human; D019713:Receptors, CCR5; D020830:rac1 GTP-Binding Protein