fumarates and Nervous-System-Diseases

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.

Topics: 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; Linear Models; Macrophages; Male; Microglia; Middle Aged; Nervous System Diseases; Oxidative Stress; Prefrontal Cortex; RNA, Small Interfering; Virus Replication

Topics: Adult; Aged; Analgesics; Central Nervous System Diseases; Cycloheptanes; Drug Synergism; Fumarates; Haloperidol; Headache; Humans; Male; Middle Aged; Nervous System Diseases; Parasympatholytics; Propylamines; Vascular Diseases