Human immunodeficiency virus type-1 vulnerates nascent neuronal cells

Area of Science:

• Neuroscience
• Immunology
• Virology

Background:

• Macrophages and microglial cells are primary targets for HIV-1 in the brain.
• HIV-1 infection can lead to neurotoxic factor release, causing neuronal damage, particularly in the basal ganglia and hippocampus.

Purpose of the Study:

• To investigate region-specific neuronal damage in the hippocampus caused by HIV-1-infected macrophages.
• To examine the impact of HIV-1-infected macrophages on neurogenesis and neuronal repair in the dentate gyrus.

Main Methods:

• Coculturing rat organotypic hippocampal slice cultures (OHC) with HIV-1-infected monocyte-derived macrophages (MDM).
• Utilizing an EGFP-expressing retrovirus vector to mark precursor cells around the dentate gyrus (DG).
• Assessing neuronal cell death via apoptosis and disturbance in neuronal projections.

Main Results:

• Neuronal cells in the granule cell layer (GCL) of the DG were preferentially killed by apoptosis.
• Projections from the GCL to the polymorphic cell layer (PCL) of the CA3 region were severely disturbed.
• Precursor cells exposed to HIV-1-infected MDM lost their ability to differentiate into neurons, and new neurons failed to incorporate into the GCL or PCL.

Conclusions:

• Neurotoxic factors from HIV-1-infected macrophages impair neuronal repair in brain tissue.
• The dentate gyrus (DG) is the most vulnerable hippocampal region to HIV-1-induced neuronal damage.
• The high rate of neurogenesis in the DG likely contributes to its selective vulnerability.