BACE1 Mediates HIV-Associated and Excitotoxic Neuronal Damage Through an APP-Dependent Mechanism

Area of Science:

• Neuroscience
• Neuropathology
• Molecular Biology

Background:

• HIV-associated neurocognitive disorders (HANDs) present symptoms overlapping with Alzheimer's disease (AD).
• Amyloid-β (Aβ) plaques, formed by Aβ oligomers, are central to AD pathogenesis.
• The role of BACE1 and Aβ production in HAND neuropathology is not fully understood.

Purpose of the Study:

• To investigate if elevated BACE1 expression and Aβ oligomer production are common in HAND.
• To determine BACE1 and APP involvement in HIV-associated neurotoxicity.
• To explore BACE1 as a potential therapeutic target for HAND.

Main Methods:

• Analysis of BACE1 and Aβ oligomer levels in the central nervous system (CNS) of HIV+ patients.
• In vitro modeling of HIV-associated neurotoxicity using rat neurons exposed to HIV-infected macrophage supernatants.
• Assessment of neuroprotection via BACE1 inhibition and genetic ablation of APP in NMDA-treated neurons.

Main Results:

• Elevated BACE1 and Aβ oligomer levels were observed in the CNS of HIV+ individuals.
• NMDAR-dependent elevation of BACE1 was found in a rat model of HIV neurotoxicity.
• BACE1 inhibition and APP knockout provided partial neuroprotection against NMDA-induced toxicity.

Conclusions:

• Increased BACE1 and subsequent Aβ oligomer production may contribute to HIV neuropathogenesis.
• BACE1 inhibition demonstrates therapeutic potential for HAND.
• APP cleavage is essential for BACE1-mediated cytotoxicity in this context.