Date Published:
2014 Oct
Publication Type:
Journal Article
Authors:
Secondary:
J Clin Invest
Volume:
124
Pagination:
4459-72
Issue:
10
PMID:
25202977
URL:
https://pubmed.ncbi.nlm.nih.gov/25202977
DOI:
10.1172/JCI72279
Keywords:
Adult;Aged;Antioxidants;Astrocytes;Brain;Central Nervous System;Cognition Disorders;Cohort Studies;Dimethyl Fumarate;Female;Fumarates;Heme Oxygenase-1;HIV Infections;HIV-1;Humans;Inflammation;Internal;Linear Models;Macrophages;Male;Microglia;Middle Aged;Nervous System Diseases;Oxidative Stress;Prefrontal Cortex;RNA, Small Interfering;Virus Replication
Abstract:
<p>Heme oxygenase-1 (HO-1) is an inducible, detoxifying enzyme that is critical for limiting oxidative stress, inflammation, and cellular injury within the CNS and other tissues. Here, we demonstrate a deficiency of HO-1 expression in the brains of HIV-infected individuals. This HO-1 deficiency correlated with cognitive dysfunction, HIV replication in the CNS, and neuroimmune activation. In vitro analysis of HO-1 expression in HIV-infected macrophages, a primary CNS HIV reservoir along with microglia, demonstrated a decrease in HO-1 as HIV replication increased. HO-1 deficiency correlated with increased culture supernatant glutamate and neurotoxicity, suggesting a link among HIV infection, macrophage HO-1 deficiency, and neurodegeneration. HO-1 siRNA knockdown and HO enzymatic inhibition in HIV-infected macrophages increased supernatant glutamate and neurotoxicity. In contrast, increasing HO-1 expression through siRNA derepression or with nonselective pharmacologic inducers, including the CNS-penetrating drug dimethyl fumarate (DMF), decreased supernatant glutamate and neurotoxicity. Furthermore, IFN-γ, which is increased in CNS HIV infection, reduced HO-1 expression in cultured human astrocytes and macrophages. These findings indicate that HO-1 is a protective host factor against HIV-mediated neurodegeneration and suggest that HO-1 deficiency contributes to this degeneration. Furthermore, these results suggest that HO-1 induction in the CNS of HIV-infected patients on antiretroviral therapy could potentially protect against neurodegeneration and associated cognitive dysfunction.</p>