Different effects of selective dopamine uptake inhibitors, GBR 12909 and WIN 35428, on HIV-1 Tat toxicity in rat fetal midbrain neurons

Abstract

Drug abuse is a risk factor for neurological complications in HIV infection. Cocaine has been shown to exacerbate HIV-associated brain pathology and enhance neurotoxicity of HIV-1 Tat and gp120 proteins. In this study, we found that the selective inhibitor of dopamine transporter (DAT) function, 1-[2-[bis(4-fluorophenyl) methoxy]ethyl]-4-(3-phenylpropyl) piperazine (GBR 12909, vanoxerine), but not the selective inhibitors of serotonin and norepinephrine (SERT and NET) transporters, sertraline and nizoxetine, emulated cocaine-mediated enhancement of Tat neurotoxicity in rat fetal midbrain primary cell cultures. Similar to cocaine, the significant increase of Tat toxicity in midbrain cell cultures was observed at micromolar dose (5 μM) of GBR 12909. However, different doses of another selective dopamine uptake inhibitor, WIN 35428 did not affect Tat neurotoxicity. The study supports the hypothesis that changes in control of dopamine (DA) homeostasis are important for the cocaine-mediated enhancement of HIV-1 Tat neurotoxicity. Our results also demonstrate that the inhibitors of DA uptake, which can bind to different domains of DAT, differ in their ability to mimic synergistic toxicity of cocaine and HIV-1 Tat in the midbrain cell culture.

Modeling Deficits in Attention, Inhibition, and Flexibility in HAND

“…Reduced DA transporter (DAT) levels in the putamen and ventral striatum are found in HIV-1+ individuals with cognitive impairment (Wang et al 2004; Chang et al , 2008). In vitro studies have shown that DAT is targeted by HIV-1 proteins Tat and gp120, resulting in transporter impairment (Aksenov et al 2008; Ferris et al 2009; Midde et al 2013; Zhu et al 2009; Zhu et al 2011), due to direct protein-protein interactions (Zhu et al 2009) involving an allosteric modulation of DAT by the Tat protein (Zhu et al 2011). In addition, DA-dependent signaling has been identified as a mechanism of HIV-1 protein neurotoxicity (Aksenova et al 2006; Silvers et al 2007; Wallace et al 2006).…”

Time and time again: Temporal processing demands implicate perceptual and gating deficits in the HIV-1 transgenic rat

“…HIV-1 Tg rats also display alterations in the DA system, with significantly lower MAO-A levels than control animals, as well as lower levels of tyrosine hydroxylase after treatment with methamphetamine (Moran et al 2012). In vitro studies have shown that DAT is targeted by HIV-1 proteins Tat and gp120, resulting in transporter impairment (Aksenov et al 2008;Ferris et al 2009;Midde et al 2013;Zhu et al 2009;Zhu et al 2011), due to direct protein-protein interactions (Zhu et al 2009) involving an allosteric modulation of DAT by the Tat protein (Zhu et al 2011). In addition, DA-dependent signaling has been identified as a mechanism of HIV-1 protein neurotoxicity (Aksenova et al 2006;Silvers et al 2007;Wallace et al 2006).…”

D1/NMDA Receptors and Concurrent Methamphetamine+HIV-1 Tat Neurotoxicity

“…Primary midbrain and hippocampal cell cultures were prepared from 18-day-old Sprague–Dawley rat fetuses as previously described (Aksenov et al 2006; 2008; Aksenova et al 2006; 2009). In brief, both the midbrain and hippocampal regions were rapidly microdissected and incubated for 15 min in a solution of 2 mg/ml trypsin in Ca2+- and Mg2+- free Hanks’ balanced salt solution (HBSS) buffered with 10 mM HEPES (Invitrogen, Carlsbad, CA).…”

“…Neuronal cell viability was assessed using a microplate reader formatted (Aksenov et al 2006, 2008, 2009; Aksenova et al 2006, 2009; Adams et al 2010) variant of the Live/Dead assay (Molecular Probes, Inc., Eugene, OR). In brief, the cleavage product of calcein AM produces a green fluorescence (F 530 nm ) when exposed to 494-nm light and is used to identify live cells.…”