Glutamate metabolism in HIV-1 infected macrophages: Role of HIV-1 Vpr.

Abstract

HIV-1 infected macrophages play a significant role in the neuropathogenesis of AIDS. HIV-1 viral protein R (Vpr) not only facilitates HIV-1 infection but also contribute to long-lived persistence in macrophages. Our previous studies using SILAC-based proteomic analysis showed that the expression of critical metabolic enzymes in the glycolytic pathway and tricarboxylic acid (TCA) cycle were altered in response to Vpr expression in macrophages. We hypothesized that Vpr-induced modulation of glycolysis and TCA cycle regulates glutamate metabolism and release in HIV-1 infected macrophages. We assessed the amount of specific metabolites induced by Vpr and HIV-1 in macrophages at the intracellular and extracellular level in a time-dependent manner utilizing multiple reaction monitoring (MRM) targeted metabolomics. In addition, stable isotope-labeled glucose and an MRM targeted metabolomics assay were used to evaluate the de novo synthesis and release of glutamate in Vpr overexpressing macrophages and HIV-1 infected macrophages, throughout the metabolic flux of glycolytic pathway and TCA cycle activation. The metabolic flux studies demonstrated an increase in glucose uptake, glutamate release and accumulation of α-ketoglutarate (α-KG) and glutamine in the extracellular milieu in Vpr expressing and HIV-1 infected macrophages. Interestingly, glutamate pools and other intracellular intermediates (glucose-6-phosphate (G6P), fructose-6-phosphate (F6P), citrate, malate, α-KG, and glutamine) showed a decreased trend except for fumarate, in contrast to the glutamine accumulation observed in the extracellular space in Vpr overexpressing macrophages. Our studies demonstrate that dysregulation of mitochondrial glutamate metabolism induced by Vpr in HIV-1 infected macrophages commonly seen, may contribute to neurodegeneration via excitotoxic mechanisms in the context of NeuroAIDS.

• Authors: Prasun K Datta, Satish Deshmane, Kamel Khalili, Salim Merali, John C Gordon, Chiara Fecchio, Carlos A Barrero
• Journal: Cell cycle (Georgetown, Tex.) (Cell Cycle) Vol. 15 Issue 17 Pg. 2288-98 (Sep 2016) ISSN: 1551-4005 [Electronic] United States
• PMID: 27245560 (Publication Type: Journal Article)

Chemical References

• Ketoglutaric Acids
• vpr Gene Products, Human Immunodeficiency Virus
• vpr protein, Human immunodeficiency virus 1
• Glutamic Acid
• Glucose

Topics

• Citric Acid Cycle (drug effects)
• Glucose (pharmacology)
• Glutamic Acid (metabolism)
• Glycolysis (drug effects)
• HIV Infections (metabolism)
• HIV-1 (physiology)
• Humans
• Ketoglutaric Acids (metabolism)
• Macrophages (drug effects, metabolism, virology)
• Metabolome (drug effects)
• Metabolomics
• Monocytes (metabolism)
• U937 Cells
• vpr Gene Products, Human Immunodeficiency Virus (metabolism)