Avdoshina Valeria, Taraballi Francesca, Dedoni Simona, Corbo Claudia, Paige Mikell, Saygideğer Kont Yasemin, Üren Aykut, Tasciotti Ennio, Mocchetti Italo
Laboratory of Preclinical Neurobiology, Department of Neuroscience, Georgetown University Medical Center, Washington, District of Columbia, USA.
Department of Regenerative Medicine, Houston Methodist Research Institute, Houston, Texas, USA.
J Neurochem. 2016 Apr;137(2):287-98. doi: 10.1111/jnc.13557. Epub 2016 Mar 15.
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.
人类免疫缺陷病毒1型（HIV）会促使突触简化和神经元凋亡，并引发被称为HIV相关神经障碍的神经损伤。HIV相关神经毒性可能由急性和慢性机制导致，而这些机制仍有待充分阐明。HIV包膜糖蛋白gp120会引发神经元变性，类似于在HIV相关神经认知障碍患者中观察到的情况。本研究旨在探寻gp120神经毒性的新机制，以解释包膜蛋白如何促进神经突修剪。已证明gp120可与神经元中的各种细胞内细胞器以及微管相结合。随后，我们运用液相色谱质谱分析法，对暴露于gp120的神经元裂解物进行分析，以寻找潜在的蛋白质相互作用因子。我们发现，与gp120相互作用的一种蛋白质是微管蛋白β-3（TUBB3），它是神经元微管的主要成分。接着，我们对gp120与神经元微管结合这一假设进行了验证。通过表面等离子体共振技术，我们证实gp120与神经元特异性TUBB3具有高亲和力结合。我们还确定了gp120与TUBB3的结合位点。然后，我们设计了一种小肽（螺旋-A），它能够使gp120无法与TUBB3结合。为了确定这种肽是否能够预防gp120介导的神经毒性，我们将螺旋-A与介孔二氧化硅纳米颗粒交联（螺旋-A纳米颗粒），以增强该肽的细胞内递送。随后，我们在大鼠皮质神经元中测试了螺旋-A纳米颗粒对三种gp120毒株的神经保护特性。螺旋-A纳米颗粒可预防gp120介导的神经突简化以及神经元损失。这些数据表明，gp120与TUBB3结合可能是gp120神经毒性的另一种机制。我们提出了一种人类免疫缺陷病毒神经毒性的新型直接机制。我们的数据显示，病毒蛋白gp120与神经元特异性微管蛋白β-3结合并阻断微管运输。通过一种小肽使gp120无法与微管蛋白结合，可预防gp120介导的神经元损失。我们的研究揭示了一个开发针对促进神经认知障碍的病毒感染辅助治疗方法的新靶点。
