HIV-1 gp120-induced axonal injury detected by accumulation of β-amyloid precursor protein in adult rat corpus callosum.
J Neuroimmune Pharmacol 2011;
6:650-7. [PMID:
21286834 DOI:
10.1007/s11481-011-9259-6]
[Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Accepted: 01/18/2011] [Indexed: 10/18/2022]
Abstract
HIV-1 brain infection induces neurodegeneration. While most studies focus on HIV-1-mediated neuronal injury, relatively few have investigated HIV-1-associated white matter damage. Corpus callosum (CC) is one of frequently involved white matter structures in HIV-1-associated white matter damage. Utilizing a model of ex vivo treatment of brain slice containing CC with HIV-1 glycoprotein 120 (gp120), we examined axonal injury by analyzing β-amyloid precursor protein (β-APP) accumulation in the axon. Incubation of CC slice with gp120 produced a significant higher density of β-APP in the CC tissue compared with non-gp120-treated controls, suggesting the presence of axonal damage in the CC. The gp120-induced CC axonal damage was blocked by a chemokine CXCR4 receptor antagonist T140 but not by an NMDA receptor blocker MK801 as demonstrated by Western blot analysis of β-APP, indicating that gp120 evokes the CC axonal injury through CXCR4 receptor. Immunocytochemical studies revealed a surprisingly high density of CXCR4-positive immunoreactivity in the CC. The CXCR4-positive labeling was distributed along the nerve fibers. Moreover, double labeling of anti-CXCR4 with either anti-neuronal nuclei or anti-myelin/oligodendrocyte-specific protein antibody revealed co-localization of CXCR4 and myelin/oligodendrocytes in some fiber-like structures, inferring that some neurons and oligodendrocytes in the CC express CXCR4. Taken together, these results indicate that gp120 induced axonal damage via CXCR4 in the CC.
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