title: Identification of a binding site of the human immunodeficiency virus envelope protein gp120 to neuronal-specific tubulin.
abstract: Human immunodeficiency virus-1 (HIV) promotes synaptic simplification and neuronal apoptosis, and causes neurological impairments termed HIV-associated neurological disorders. HIV-associated neurotoxicity may be brought about by acute and chronic mechanisms that still remain to be fully characterized. The HIV envelope glycoprotein gp120 causes neuronal degeneration similar to that observed in HIV-associated neurocognitive disorders subjects. This study was undertaken to discover novel mechanisms of gp120 neurotoxicity that could explain how the envelope protein promotes neurite pruning. Gp120 has been shown to associate with various intracellular organelles as well as microtubules in neurons. We then analyzed lysates of neurons exposed to gp120 with liquid chromatography mass spectrometry for potential protein interactors. We found that one of the proteins interacting with gp120 is tubulin β-3 (TUBB3), a major component of neuronal microtubules. We then tested the hypothesis that gp120 binds to neuronal microtubules. Using surface plasmon resonance, we confirmed that gp120 binds with high affinity to neuronal-specific TUBB3. We have also identified the binding site of gp120 to TUBB3. We then designed a small peptide (Helix-A) that displaced gp120 from binding to TUBB3. To determine whether this peptide could prevent gp120-mediated neurotoxicity, we cross-linked Helix-A to mesoporous silica nanoparticles (Helix-A nano) to enhance the intracellular delivery of the peptide. We then tested the neuroprotective property of Helix-A nano against three strains of gp120 in rat cortical neurons. Helix-A nano prevented gp120-mediated neurite simplification as well as neuronal loss. These data propose that gp120 binding to TUBB3 could be another mechanism of gp120 neurotoxicity. We propose a novel direct mechanism of human immunodeficiency virus neurotoxicity. Our data show that the viral protein gp120 binds to neuronal specific tubulin β-3 and blocks microtubule transport. Displacing gp120 from binding to tubulin by a small peptide prevents gp120-mediated neuronal loss. Our study reveals a novel target for developing adjunct therapies against viral infection that promotes neurocognitive disorders.
authors.affiliation: Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA.
authors.forename: Valeria
authors.initials: V
authors.lastname: Avdoshina
authors.affiliation: Department of Regenerative Medicine, Houston Methodist Research Institute, Houston, Texas, USA.
authors.forename: Francesca
authors.initials: F
authors.lastname: Taraballi
authors.affiliation: Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA.
authors.forename: Simona
authors.initials: S
authors.lastname: Dedoni
authors.affiliation: Department of Regenerative Medicine, Houston Methodist Research Institute, Houston, Texas, USA.|Fondazione SDN, Naples, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Corbo
authors.affiliation: Department of Chemistry and Biochemistry, George Mason University, Fairfax, Virginia, USA.
authors.forename: Mikell
authors.initials: M
authors.lastname: Paige
authors.affiliation: Department of Oncology, Georgetown University Medical Center, Washington, District of Columbia, USA.
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Saygideğer Kont
authors.affiliation: Department of Oncology, Georgetown University Medical Center, Washington, District of Columbia, USA.
authors.forename: Aykut
authors.initials: A
authors.lastname: Üren
authors.affiliation: Department of Regenerative Medicine, Houston Methodist Research Institute, Houston, Texas, USA.
authors.forename: Ennio
authors.initials: E
authors.lastname: Tasciotti
authors.affiliation: Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA.
authors.forename: Italo
authors.initials: I
authors.lastname: Mocchetti
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000187:drug effects / Q000502:physiology*; D016923:Cell Death / Q000187:drug effects; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D002853:Chromatography, Liquid; D004622:Embryo, Mammalian; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D046529:Microscopy, Electron, Transmission; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D008958:Models, Molecular; D053758:Nanoparticles / Q000378:metabolism / Q000648:ultrastructure; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D020349:Surface Plasmon Resonance; D014404:Tubulin / Q000378:metabolism*
chemical_list: D015699:HIV Envelope Protein gp120; D008869:Microtubule-Associated Proteins; D010455:Peptides; C498585:TUBB3 protein, human; D014404:Tubulin
keywords: HAND; Tat; nanoparticles; neurite pruning; neuronal loss; tubulin β-3
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