The anti-HIV pseudopeptide HB-19 forms a complex with the cell-surface-expressed nucleolin independent of heparan sulfate proteoglycans.
The HB-19 pseudopeptide 5[Kpsi(CH(2)N)PR]-TASP, psi(CH(2)N) for reduced peptide bond, is a specific inhibitor of human immunodeficiency virus (HIV) infection in different CD4(+) cell lines and in primary T-lymphocytes and macrophages. Here, by using an experimental CD4(+) cell model to monitor HIV entry and infection, we demonstrate that HB-19 binds the cell surface and inhibits attachment of HIV particles to permissive cells. At concentrations that inhibit HIV attachment, HB-19 binds cells irreversibly, becomes complexed with the cell-surface-expressed nucleolin, and eventually results in its degradation. Accordingly, by confocal immunofluorescence microscopy, we demonstrate the drastic reduction of the cell-surface-expressed nucleolin following treatment of cells with HB-19. HIV particles can prevent the binding of HB-19 to cells and inhibit complex formation with nucleolin. Such a competition between viral particles and HB-19 is consistent with the implication of nucleolin in the process of HIV attachment to target cells. We show that another inhibitor of HIV infection, the fibroblast growth factor-2 (FGF-2) that uses cell-surface-expressed heparan sulfate proteoglycans as low affinity receptors, binds cells and blocks attachment of HIV to permissive cells. FGF-2 does not prevent the binding of HB-19 to cells and to nucleolin, and similarly HB-19 has no apparent effect on the binding of FGF-2 to the cell surface. The lack of competition between these two anti-HIV agents rules out the potential involvement of heparan sulfate proteoglycans in the mechanism of anti-HIV effect of HB-19, thus pointing out that nucleolin is its main target.
Nisole
S
S
Unité de Virologie et Immunologie Cellulaire, URA 1930 CNRS, Institut Pasteur, 28 rue du Dr Roux, 75724 Paris Cedex 15, France.
Krust
B
B
Callebaut
C
C
Guichard
G
G
Muller
S
S
Briand
J P
JP
Hovanessian
A G
AG
D019380:Anti-HIV Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D001665:Binding Sites; D015496:CD4-Positive T-Lymphocytes / Q000821:virology*; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology / Q000821:virology; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism / Q000494:pharmacology; D005434:Flow Cytometry; D015497:HIV-1 / Q000187:drug effects* / Q000502:physiology; D019812:Heparan Sulfate Proteoglycans / Q000378:metabolism*; D006801:Humans; D018613:Microscopy, Confocal; D009842:Oligopeptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D010455:Peptides; D010742:Phospholipid Ethers / Q000494:pharmacology; D010750:Phosphoproteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000097796:Nucleolin
D019380:Anti-HIV Agents; D016222:Fibroblast Growth Factor 2; D019812:Heparan Sulfate Proteoglycans; D009842:Oligopeptides; D010455:Peptides; D010742:Phospholipid Ethers; D010750:Phosphoproteins; D011506:Proteins; D016601:RNA-Binding Proteins; D000097796:Nucleolin; C096487:CP 51; C121944:HB-19 peptide