CROI 2015 Program and Abstracts

Abstract Listing

Poster Abstracts

suggesting a model in which complex inter-relationships between monoamine metabolism and mitochondrial bioenergetics contribute to biological mechanisms involved in depression that may be augmented by inflammation during HIV infection. Conclusions: Integrated approaches targeting inflammation, monoamine metabolism (tryptophan [serotonin], phenylalanine [dopamine], and trace amines), and mitochondrial pathways may be important for prevention and treatment of depression in people with and without HIV. 499 Mitochondrial Injury and Cognitive Function in HIV Infection and Methamphetamine Susanna R. Var ;Tyler R. Day; AndrejVitomirov; Davey M. Smith;Virawudh Soontornniyomkij; Cristian L. Achim; Sanjay Mehta; Josué Pérez-Santiago University of California San Diego, San Diego, CA, US Background: Mitochondria carry their genome and are critical in providing energy for cellular processes in the central nervous system (CNS). Damage to mitochondrial DNA (mtDNA) is associated with many neurodegenerative diseases. HIV infection and methamphetamine (METH) abuse, a common comorbidity, can cause damage to mtDNA and subsequently lead to neurocognitive morbidity. Here we evaluated the role of mitochondrial injury in relation to HIV infection and METH use. Methods: We collected brain tissue of parietal and frontal lobes from HIV-infected individuals with evidence of METH use (n=6), HIV-infected individuals with no METH use (n=4) and HIV-negative controls (n=7) from the National NeuroAids Tissue Consortium. DNA was extracted from gray and white matter from each lobe. We quantified mtDNA levels and mitochondria carrying the “common deletion” as a measurement of mitochondrial injury in relation to a cellular control using droplet digital PCR (ddPCR). Measures of mtDNA and “common deletion” were evaluated in relation to clinical Global Deficiency Score and other clinical variables. Results: Our examination of all groups together found that levels of “common deletion” increased with age in the parietal white (r=0.75, p=0.0005) and grey matter (r=0.60, p=0.01), and frontal white (r=0.43, p=0.08) and gray matter (r=0.55, p=0.02). After excluding the three participants with Alzheimer’s Disease, one per group, which is known to increase the relative proportion of “common deletion” in brain tissue, we found that a higher relative proportion of mtDNA with the “common deletion” was associated with worse neurocognitive impairment (r=0.99, p=0.003) only in the parietal white matter of HIV-infected individuals not using METH. Interestingly, in the parietal white matter of HIV-infected METH users, a higher relative proportion of “common deletion” was associated with higher CD4 counts, and inversely with degree of impairment (r=-0.86, p=0.06). Conclusions: While an increased proportion of mtDNA carrying the “common deletion” was associated with increasing neurocognitive impairment in HIV-infected individuals as expected, METH use appeared to provide a protective effect. METH has been shown to increase autophagy and be neuroprotective at low doses. Further work is required to explore the role of mitochondrial injury in HIV-infected individuals and the effects of METH use on this damage. 500 Efavirenz-Induced Nitric Oxide Affects Mitochondrial Function in Glial Cells Haryes A. Funes 1 ; Fernando Alegre 2 ; Miriam Polo 2 ; Ana Blas-García 2 ; Juan V. Espluges 3 ; Nadezda Apostolova 4 1 Universidad de Valencia, Valencia, Spain; 2 Universidad de Valencia/FISABIO, Valencia, Spain; 3 Universidad de Valencia/FISABIO/CIBERehd, Valencia, Spain; 4 Universidad Jaume I, Castellón, Spain Background: Neurological pathogenesis is closely associated with mitochondria. Nitric oxide (NO) is a ubiquitous central nervous system (CNS) mediator implicated in both mitochondrial dysfunction and inflammation. More than 50% of Efavirenz (EFV)-treated patients exhibit CNS-related effects that often require discontinuation of the therapy; moreover this drug has been recently linked to the development of HIV-associated neurological disorder (HAND). The underlying mechanisms of these effects are unknown however, recent evidence points to mitochondrial dysfunction. We analysed the ability of EFV to regulate NO generation in neurons and glial cells and the involvement of NO in the mitochondrial action of this anti-HIV. Methods: Human cell lines glioma (U-251MG) and neuroblastoma (SH-SY5Y) and primary cultures of rat cortical neurons and astrocytes were exposed to short-term treatment with clinically relevant concentrations of EFV. Results: EFV up-regulated inducible nitric oxide synthase (iNOS), thus enhancing NO production in glial cells whereas no up-regulation of NOS was observed in neurons. Incremented NO levels in glial cells had a bearing on mitochondrial function, as decreased overall O 2 consumption and increased mitochondrial superoxide generation induced by EFV were partially restored when NOS activation was pharmacologically inhibited. Analysis of the activity of the mitochondrial electron transport chain complexes revealed a major inhibitory effect of this drug on CI in both glial cells and neurons (1 and 6h), while other complexes were also affected (CIII and CIV) in glial cells (6 and 24h respectively). NO is capable of inhibiting and/or irreversibly damaging CIV, this possibility was endorsed by the fact that the decrease in CIV activity was reversed when a NOS inhibitor was added. Moreover, NO seems to be relevant to the bioenergetics effect of EFV observed in glial cells, as it was involved in the up-regulation of glycolysis that followed the mitochondrial interference induced by the drug. Conclusions: EFV induces the synthesis of NO in glial cells which interferes with mitochondrial function in these cells, an effect not observed in neurons. These findings shed light on the mechanisms of the CNS side-effects of this drug, including the neuropsychiatric symptoms that appear soon after initiation of EFV therapy, which are sometimes accompanied by neuroinflammation, and long-term effects such as HAND.

Poster Abstracts

THURSDAY, FEBRUARY 26, 2015 Session P-G9 Poster Session

Poster Hall

2:30 pm– 4:00 pm Neuropathogenesis Mechanisms 501 Role of HIV Strain, Accessory Proteins, and Cytokines in Macrophage HO-1 Deficiency Alexander J. Gill ; Patricia J.Vance; Ronald G. Collman; Dennis L. Kolson University of Pennsylvania, Philadelphia, PA, US

Background: Protein expression of the cytoprotective enzyme heme oxygenase-1 (HO-1) is reduced in the prefrontal cortex of HIV+ individuals and negatively correlates with CNS viral replication and neuroinflammation. HIV infection of monocyte-derived macrophages (MDM) reduces HO-1 protein expression and pharmacologic rescue of HO-1 expression ameliorates HIV-MDM neurotoxin production. We now present data describing the change in HO-1 expression and neurotoxicity in MDM infected with 13 distinct HIV strains and the role of HIV accessory proteins and cytokine signaling in HIV-mediated HO-1 loss. Methods: Using 13 macrophage-tropic HIV-1 strains, we infected MDM and determined the association between supernatant viral replication, glutamate, and neurotoxicity and HO-1 protein expression as measured by reverse transcriptase (RT) activity, enzymatic assay, neuron-based MAP2 ELISA, and Western blot analysis, respectively, on day 12 post- infection. Data was analyzed by ANOVA with Holm-Sidak post-test or Pearson’s correlation.

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CROI 2015