title: Glutamate production by HIV-1 infected human macrophage is blocked by the inhibition of glutaminase.
abstract: Mononuclear phagocyte (macrophages and microglia) dysfunction plays a significant role in the pathogenesis of human immunodeficiency virus (HIV) associated dementia (HAD) through the production and release of soluble neurotoxic factors including glutamate. The mechanism of glutamate regulation by HIV-1 infection remains unclear. In this report, we investigated whether the enzyme glutaminase is responsible for glutamate generation by HIV-1 infected monocyte-derived macrophages. We tested the functionality of novel small molecule inhibitors designed to specifically block the activity of glutaminase. Glutaminase inhibitors were first characterized in a kinetic assay with crude glutaminase from rat brain revealing an uncompetitive mechanism of inhibition. The inhibitors were then tested in vitro for their ability to prevent glutamate generation by HIV-infected macrophages, their effect upon macrophage viability, and HIV infection. To validate these findings, glutaminase specific siRNA was tested for its ability to prevent glutamate increase during infection. Our results show that both glutaminase specific small molecule inhibitors and glutaminase specific siRNA were effective at preventing increases in glutamate by HIV-1 infected macrophage. These findings support glutaminase as a potential component of the HAD pathogenic process and identify a possible therapeutic avenue for the treatment of neuroinflammatory states such as HAD.
authors.affiliation: Laboratory of Neurotoxicology, Center for Neurovirology and Neurodegenerative Disorders, Department of PharmacologyUniversity of Nebraska Medical Center, Omaha, Nebraska 68198-5880, USA.
authors.forename: Nathan
authors.initials: N
authors.lastname: Erdmann
authors.forename: Jianxing
authors.initials: J
authors.lastname: Zhao
authors.forename: Alicia L
authors.initials: AL
authors.lastname: Lopez
authors.forename: Shelley
authors.initials: S
authors.lastname: Herek
authors.forename: Norman
authors.initials: N
authors.lastname: Curthoys
authors.forename: Terry D
authors.initials: TD
authors.lastname: Hexum
authors.forename: Takashi
authors.initials: T
authors.lastname: Tsukamoto
authors.forename: Dana
authors.initials: D
authors.lastname: Ferraris
authors.forename: Jialin
authors.initials: J
authors.lastname: Zheng
mesh_terms: D015526:AIDS Dementia Complex / Q000378:metabolism* / Q000503:physiopathology / Q000821:virology; D001681:Biological Assay / Q000379:methods; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D018698:Glutamic Acid / Q000096:biosynthesis*; D005972:Glutaminase / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015497:HIV-1 / Q000378:metabolism* / Q000472:pathogenicity; D006801:Humans; D008264:Macrophages / Q000378:metabolism* / Q000821:virology; D034741:RNA, Small Interfering / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D034741:RNA, Small Interfering; D018698:Glutamic Acid; D005972:Glutaminase