Abstract
Cell-mediated transmission and dissemination of sexually-acquired human immunodeficiency virus 1 (HIV-1) in the host involves the migration of immature dendritic cells (iDCs). iDCs migrate in response to the HIV-1 envelope protein, gp120, and inhibiting such migration may limit the mucosal transmission of HIV-1. In this study, we elucidated the mechanism of HIV-1-gp120-induced transendothelial migration of iDCs. We found that gp120 enhanced the binding of Wiskott-Aldrich Syndrome protein (WASp) and the Actin-Related Protein 2/3 (Arp2/3) complex with β-actin, an interaction essential for the proper formation of podosomes, specialized adhesion structures required for the migration of iDCs through different tissues. We further identified Leukocyte-Specific Protein 1 (LSP1) as a novel component of the WASp-Arp2/3-β-actin complex. Pretreating iDCs with an active fragment of the secretory glycoprotein Slit2 (Slit2N) inhibited HIV-1-gp120-mediated migration and podosome formation, by inducing the cognate receptor Roundabout 1 (Robo1) to bind to and sequester WASp and LSP1 from β-actin. Slit2N treatment also inhibited Src signaling and the activation of several downstream molecules, including Rac1, Pyk2, paxillin, and CDC42, a major regulator of podosome formation. Taken together, our results support a novel mechanism by which Slit2/Robo1 may inhibit the HIV-1-gp120-induced migration of iDCs, thereby restricting dissemination of HIV-1 from mucosal surfaces in the host.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Actin-Related Protein 2-3 Complex / immunology
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Actin-Related Protein 2-3 Complex / metabolism
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Actins / immunology
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Actins / metabolism
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Blotting, Western
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Cell Movement / immunology*
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Cells, Cultured
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Dendritic Cells / immunology*
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Dendritic Cells / metabolism
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Focal Adhesion Kinase 2 / immunology
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Focal Adhesion Kinase 2 / metabolism
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HIV Envelope Protein gp120 / immunology*
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HIV Envelope Protein gp120 / metabolism
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Human Umbilical Vein Endothelial Cells / immunology
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Human Umbilical Vein Endothelial Cells / metabolism
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Humans
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Intercellular Signaling Peptides and Proteins / immunology*
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Intercellular Signaling Peptides and Proteins / metabolism
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Microfilament Proteins / genetics
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Microfilament Proteins / immunology*
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Microfilament Proteins / metabolism
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Microscopy, Confocal
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Nerve Tissue Proteins / immunology*
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Nerve Tissue Proteins / metabolism
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Paxillin / immunology
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Paxillin / metabolism
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Protein Binding / immunology
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Proto-Oncogene Proteins pp60(c-src) / immunology
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Proto-Oncogene Proteins pp60(c-src) / metabolism
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Pseudopodia / immunology
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RNA Interference
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Receptors, Immunologic / immunology*
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Receptors, Immunologic / metabolism
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Roundabout Proteins
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Signal Transduction / immunology
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Wiskott-Aldrich Syndrome Protein / immunology*
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Wiskott-Aldrich Syndrome Protein / metabolism
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cdc42 GTP-Binding Protein / immunology
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cdc42 GTP-Binding Protein / metabolism
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rac1 GTP-Binding Protein / immunology
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rac1 GTP-Binding Protein / metabolism
Substances
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Actin-Related Protein 2-3 Complex
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Actins
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HIV Envelope Protein gp120
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Intercellular Signaling Peptides and Proteins
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LSP1 protein, human
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Microfilament Proteins
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Nerve Tissue Proteins
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Paxillin
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Receptors, Immunologic
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Wiskott-Aldrich Syndrome Protein
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Focal Adhesion Kinase 2
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Proto-Oncogene Proteins pp60(c-src)
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cdc42 GTP-Binding Protein
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rac1 GTP-Binding Protein
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Slit homolog 2 protein