HIV-1 Tat and opioids act independently to limit antiretroviral brain concentrations and reduce blood-brain barrier integrity.

Poor antiretroviral penetration may contribute to human immunodeficiency virus (HIV) persistence within the brain and to neurocognitive deficits in opiate abusers. To investigate this problem, HIV-1 Tat protein and morphine effects on blood-brain barrier (BBB) permeability and drug brain penetration were explored using a conditional HIV-1 Tat transgenic mouse model. Tat and morphine effects on the leakage of fluorescently labeled dextrans (10-, 40-, and 70-kDa) into the brain were assessed. To evaluate effects on antiretroviral brain penetration, Tat+ and Tat- mice received three antiretroviral drugs (dolutegravir, abacavir, and lamivudine) with or without concurrent morphine exposure. Antiretroviral and morphine brain and plasma concentrations were determined by LC-MS/MS. Morphine exposure, and, to a lesser extent, Tat, significantly increased tracer leakage from the vasculature into the brain. Despite enhanced BBB breakdown evidenced by increased tracer leakiness, morphine exposure led to significantly lower abacavir concentrations within the striatum and significantly less dolutegravir within the hippocampus and striatum (normalized to plasma). P-glycoprotein, an efflux transporter for which these drugs are substrates, expression and function were significantly increased in the brains of morphine-exposed mice compared to mice not exposed to morphine. These findings were consistent with lower antiretroviral concentrations in brain tissues examined. Lamivudine concentrations were unaffected by Tat or morphine exposure. Collectively, our investigations indicate that Tat and morphine differentially alter BBB integrity. Morphine decreased brain concentrations of specific antiretroviral drugs, perhaps via increased expression of the drug efflux transporter, P-glycoprotein.

HIV infection and age effects on striatal structure are additive.

The age of the HIV-infected population is increasing. Although many studies document gray matter volume (GMV) changes following HIV infection, GMV also declines with age. Findings have been inconsistent concerning interactions between HIV infection and age on brain structure. Effects of age, substance use, and inadequate viral suppression may confound identification of GMV serostatus effects using quantitative structural measures. In a cross-sectional study of HIV infection, including 97 seropositive and 84 seronegative, demographically matched participants, ages 30-70, we examined serostatus and age effects on GMV and neuropsychological measures. Ninety-eight percent of seropositive participants were currently treated with anti-retroviral therapies and all were virally suppressed. Gray, white, and CSF volumes were estimated using high-resolution T1-weighted MRI. Linear regression modeled effects of serostatus, age, education, comorbidities, and magnetic field strength on brain structure, using both a priori regions and voxel-based morphometry. Although seropositive participants exhibited significant bilateral decreases in striatal GMV, no serostatus effects were detected in the thalamus, hippocampus, or cerebellum. Age was associated with cortical, striatal, thalamic, hippocampal, and cerebellar GMV reductions. Effects of age and serostatus on striatal GMV were additive. Although no main effects of serostatus on neuropsychological performance were observed, serostatus moderated the relationship between pegboard performance and striatal volume. Both HIV infection and age were associated with reduced striatal volume. The lack of interaction of these two predictors suggests that HIV infection is associated with premature, but not accelerated, brain age. In serostatus groups matched on demographic and clinical variables, there were no observed differences in neuropsychological performance. Striatal GMV measures may be promising biomarker for use in studies of treated HIV infection.

Effects of docosahexaenoic acid on locomotor activity in ethanol-treated HIV-1 transgenic rats.

Binge drinking affects the onset and progression of human immunodeficiency virus (HIV)-associated neurological disorders. The HIV-1 transgenic (HIV-1Tg) rat was created with a gag- and pol-deleted HIV-1 viral genome to mimic HIV-infected patients receiving combination anti-retroviral therapy (cART). Docosahexaenoic acid (DHA) is a marine compound that modulates inflammatory responses. Using HIV-1Tg rats subjected to binge exposure to ethanol (EtOH), this study examined whether DHA could reduce the detrimental neurological effects of EtOH and HIV proteins. Young adult male HIV-1Tg and F344 control rats received 4 mL/kg/day saline as a control (Saline group), 20 mg/kg/day DHA (DHA group), 4.8 g/kg/day 52% w/v EtOH (EtOH group), or 4.8 g/kg/day 52% w/v EtOH and 20 mg/kg/d DHA (DHA + EtOH group) by gavage for 5 weeks (n = 6 per group). EtOH was administrated on days 5, 6, and 7 of each week. Locomotor activity (LMA) was assessed using open field tests before and 45, 90, 135, and 180 min after each treatment. Repeated binge EtOH exposure gradually decreased LMA measured before daily treatments in HIV-1Tg and F344 rats, an effect that was reversed by DHA only in the HIV-1Tg rats. Decreased LMA of rats after treatment and under the influence of EtOH was less pronounced, and the reversal effect of DHA did not reach statistical significance. The plasma endotoxin level was significantly higher in HIV-1Tg rats than in F344 rats. IL-6 and IL-18 expression in the striatum was significantly higher in the HIV-1Tg EtOH group than in the F344 EtOH group. DHA significantly decreased the high levels of IL-6, IL-18, and NF-κB expression observed in the HIV-1Tg EtOH group. DHA appears to ameliorate inflammation and consequently lessen the reductions in LMA produced by the combination of EtOH and HIV-1 viral proteins.

Axonal transport of AAV9 in nonhuman primate brain.

A pilot study in nonhuman primates was conducted, in which two Rhesus macaques received bilateral parenchymal infusions of adeno-associated virus serotype 9 encoding green fluorescent protein (AAV9-GFP) into each putamen. The post-surgical in-life was restricted to 3 weeks in order to minimize immunotoxicity expected to arise from expression of GFP in antigen-presenting cells. Three main findings emerged from this work. First, the volume over which AAV9 expression was distributed (Ve) was substantially greater than the volume of distribution of MRI signal (Vd). This stands in contrast with Ve/Vd ratio of rAAV2, which is lower under similar conditions. Second, post-mortem analysis revealed expression of GFP in thalamic and cortical neurons as well as dopaminergic neurons projecting from substantia nigra pars compacta, indicating retrograde transport of AAV9. However, fibers in the substantia nigra pars reticulata, a region that receives projections from putamen, also stained for GFP, indicating anterograde transport of AAV9 as well. Finally, one hemisphere received a 10-fold lower dose of vector compared with the contralateral hemisphere (1.5 × 10(13) vg ml(-1)) and we observed a much stronger dose effect on anterograde-linked than on retrograde-linked structures. These data suggest that AAV9 can be axonally transported bi-directionally in the primate brain. This has obvious implications to the clinical developing of therapies for neurological disorders like Huntington's or Alzheimer's diseases.

Recombinant Adeno Associated Viral (AAV) vector type 9 delivery of Ex1-Q138-mutant huntingtin in the rat striatum as a short-time model for in vivo studies in drug discovery.

Huntington's disease (HD) is an inherited neurodegenerative disorder characterized by dyskinesia, cognitive impairment and emotional disturbances, presenting progressive neurodegeneration in the striatum and intracellular mutant Huntingtin (mHTT) aggregates in various areas of the brain. Recombinant Adeno Associated Viral (rAAV) vectors have been successfully used to transfer foreign genes to the brain of adult animals. In the present study we report a novel in vivo rat HD model obtained by stereotaxic injection of rAAV serotype2/9 containing Exon1-Q138 mHTT (Q138) and Exon1-Q17 wild type HTT (Q17; control), respectively in the right and in the left striatum, and expressed as C-terminal GFP fusions to facilitate detection of infected cells and aggregate production. Immunohistochemical analysis of brain slices from animals sacrificed twenty-one days after viral infection showed that Q138 injection resulted in robust formation of GFP-positive aggregates in the striatum, increased GFAP and microglial activation and neurodegeneration, with little evidence of any of these events in contralateral tissue infected with wild type (Q17) expressing construct. Differences in the relative metabolite concentrations (N-Acetyl Aspartate/Creatine and Myo-Inositol/Creatine) were observed by H1 MR Spectroscopy. By quantitative RT-PCR we also demonstrated that mHTT induced changes in the expression of genes previously shown to be altered in other rodent HD models. Importantly, administration of reference compounds previously shown to ameliorate the aggregation and neurodegeneration phenotypes in preclinical HD models was demonstrated to revert the mutant HTT-dependent effects in our model. In conclusion, the AAV2/9-Q138/Q17 exon 1 HTT stereotaxic injection represents a useful first-line in vivo preclinical model for studying the biology of mutant HTT exon 1 in the striatum and to provide early evidence of efficacy of therapeutic approaches.

Decreased glial and synaptic glutamate uptake in the striatum of HIV-1 gp120 transgenic mice.

The mechanisms leading to the neurocognitive deficits in humans with immunodeficiency virus type 1 (HIV-1) are not well resolved. A number of cell culture models have demonstrated that the HIV-envelope glycoprotein 120 (gp120) decreases the reuptake of glutamate, which is necessary for learning, memory, and synaptic plasticity. However, the impact of brain HIV-1 gp120 on glutamate uptake systems in vivo remains unknown. Notably, alterations in brain glutamate uptake systems are implicated in a number of neurodegenerative and neurocognitive disorders. We characterized the kinetic properties of system XAG (sodium-dependent) and systems xc- (sodium-independent) [3H]-L-glutamate uptake in the striatum and hippocampus of HIV-1 gp120 transgenic mice, an established model of HIV neuropathology. We determined the kinetic constant Vmax (maximal velocity) and Km (affinity) of both systems XAG and xc- using subcellular preparations derived from neurons and glial cells. We show significant (30-35 %) reductions in the Vmax of systems XAG and xc- in both neuronal and glial preparations derived from the striatum, but not from the hippocampus of gp120 mice relative to wild-type (WT) controls. Moreover, immunoblot analysis showed that the protein expression of glutamate transporter subtype-1 (GLT-1), the predominant brain glutamate transporter, was significantly reduced in the striatum but not in the hippocampus of gp120 mice. These extensive and region-specific deficits of glutamate uptake likely contribute to the development and/or severity of HIV-associated neurocognitive disorders. Understanding the role of striatal glutamate uptake systems in HIV-1 gp120 may advance the development of new therapeutic strategies to prevent neuronal damage and improve cognitive function in HIV patients.

Longitudinal cerebral metabolic changes in pig-tailed macaques infected with the neurovirulent virus SIVsmmFGb.

Longitudinal cerebral metabolite changes in pig-tailed macaques inoculated with the simian immunodeficiency virus SIVsmmFGb were evaluated with in vivo proton MRS at 3 T. Blood sample collection, and MRS were carried out before and 2, 4, 8, 12, 16, 20, and 24 weeks after SIV inoculation. Significant reduction of N-acetylaspartate (NAA)/creatine (Cr) and choline (Cho)/Cr ratios in prefrontal gray matter (PGM) and glutamate/glutamine(Glx)/Cr ratio in striatum, and increase of myo-inositol (mI)/Cr in striatum were observed during acute SIV infection. The metabolite alterations during the SIVsmmFGb infection are largely in agreement with previous findings in other non-human primate models and HIV patients. Also, NAA/Cr in PGM and striatum and Glx/Cr in striatum are negatively correlated with the percentage of CD8+ T cells after the SIV infection, suggesting the interaction between brain metabolite and immune dysfunction. The present study complements previous studies by describing the time course of alterations of brain metabolites during SIVsmmFGb infection. The findings further demonstrate the efficacy of the SIVsmmFGb-infected macaque as a model to characterize central nervous system infection using novel neuroimaging approaches and also as a tool for exploration of novel and advanced neuroimaging techniques in HIV/AIDS studies.

Up-regulation of the neuronal nicotinic receptor α7 by HIV glycoprotein 120: potential implications for HIV-associated neurocognitive disorder.

Approximately 30-50% of the >30 million HIV-infected subjects develop neurological complications ranging from mild symptoms to dementia. HIV does not infect neurons, and the molecular mechanisms behind HIV-associated neurocognitive decline are not understood. There are several hypotheses to explain the development of dementia in HIV(+) individuals, including neuroinflammation mediated by infected microglia and neuronal toxicity by HIV proteins. A key protein associated with the neurological complications of HIV, gp120, forms part of the viral envelope and can be found in the CSF of infected individuals. HIV-1-gp120 interacts with several receptors including CD4, CCR5, CXCR4, and nicotinic acetylcholine receptors (nAChRs). However, the role of nAChRs in HIV-associated neurocognitive disorder has not been investigated. We studied the effects of gp120(IIIB) on the expression and function of the nicotinic receptor α7 (α7-nAChR). Our results show that gp120, through activation of the CXCR4 chemokine receptor, induces a functional up-regulation of α7-nAChRs. Because α7-nAChRs have a high permeability to Ca(2+), we performed TUNEL staining to investigate the effects of receptor up-regulation on cell viability. Our data revealed an increase in cell death, which was blocked by the selective antagonist α-bungarotoxin. The in vitro data are supported by RT-PCR and Western blot analysis, confirming a remarkable up-regulation of the α7-nAChR in gp120-transgenic mice brains. Specifically, α7-nAChR up-regulation is observed in mouse striatum, a region severely affected in HIV(+) patients. In summary, CXCR4 activation induces up-regulation of α7-nAChR, causing cell death, suggesting that α7-nAChR is a previously unrecognized contributor to the neurotoxicity associated with HIV infection.

Viral vector-mediated overexpression of estrogen receptor-alpha in striatum enhances the estradiol-induced motor activity in female rats and estradiol-modulated GABA release.

Classical estrogen receptor-signaling mechanisms involve estradiol binding to intracellular nuclear receptors [estrogen receptor-alpha (ERalpha) and estrogen receptor-beta (ERbeta)] to promote changes in protein expression. Estradiol can also exert effects within seconds to minutes, however, a timescale incongruent with genomic signaling. In the brain, estradiol rapidly potentiates stimulated dopamine release in the striatum of female rats and enhances spontaneous rotational behavior. Furthermore, estradiol rapidly attenuates the K(+)-evoked increase of GABA in dialysate. We hypothesize that these rapid effects of estradiol in the striatum are mediated by ERalpha located on the membrane of medium spiny GABAergic neurons. This experiment examined whether overexpression of ERalpha in the striatum would enhance the effect of estradiol on rotational behavior and the K(+)-evoked increase in GABA in dialysate. Ovariectomized female rats were tested for rotational behavior or underwent microdialysis experiments after unilateral intrastriatal injections of a recombinant adeno-associated virus (AAV) containing the human ERalpha cDNA (AAV.ERalpha) into the striatum; controls received either the same vector into areas outside the striatum or an AAV containing the human alkaline phosphatase gene into the striatum (AAV.ALP). Animals that received AAV.ERalpha in the striatum exhibited significantly greater estradiol-induced contralateral rotations compared with controls and exhibited behavioral sensitization of contralateral rotations induced by a low-dose of amphetamine. ERalpha overexpression also enhanced the inhibitory effect of estradiol on K(+)-evoked GABA release suggesting that disinhibition of dopamine release from terminals in the striatum resulted in the enhanced rotational behavior.

Stable transgene expression from HSV amplicon vectors in the brain: potential involvement of immunoregulatory signals.

The herpes simplex virus (HSV) amplicon is a plasmid-based, infectious gene delivery system that carries up to 150 kilobase (kb) of exogenous DNA. We previously characterized early host responses and stability of transgene expression in mice systemically injected with HSV amplicon vectors. Transgene expression was readily detected primarily in the liver but rapidly declined to undetectable levels within 2 weeks. Molecular analyses revealed induction of type I interferons (IFN) as the primary response, and early transcriptional silencing of the vector followed IFN's activation of signal transducers and activators of transcription 1 (STAT1). In this study, we investigate vector administration by stereotactic injection into the striatum. In the brain, induction of type I IFN was rather modest, and transgene expression lasted more than 1 year despite dose-dependent inflammation and infiltration of immune cells around injection sites. Further analyses revealed dose-dependent upregulation of immunosuppressive cytokines and molecular markers specific to regulatory T cells in the injected brain regions, which supported the immune-privileged properties of the brain parenchyma. Overall, our findings indicate that the spectrum of host responses can differ significantly depending on target organs and administrative routes, and that HSV amplicon vectors hold great potential for gene therapy of chronic neurological disorders.

Compromised fronto-striatal functioning in HIV: an fMRI investigation of semantic event sequencing.

The human immunodeficiency virus (HIV) damages fronto-striatal regions, and is associated with deficits in executive functioning. We recently developed a semantic event sequencing task based on the Picture Arrangement subtest of the Wechsler Adult Intelligence Scale-III for use with functional magnetic resonance imaging (fMRI) and found recruitment of dorsolateral prefrontal cortex and basal ganglia in healthy participants. To assess the impact of HIV on the functioning of the basal ganglia and prefrontal cortex, we administered this task to 11 HIV+ and 11 Control participants matched for age and education. Neuropsychological evaluation demonstrated that the HIV+ group had mild impairment in memory retrieval and motor functioning, but was not demented. Morphometric measurements suggested no atrophy in basal ganglia regions. The results of the fMRI analysis revealed hypoactivation of the left caudate, left dorsolateral prefrontal cortex, and bilateral ventral prefrontal cortex in the HIV+ group. Functional connectivity analysis demonstrated less functional connectivity between the caudate and prefrontal cortex and basal ganglia regions in the HIV+ group. In contrast, the HIV+ group demonstrated increased activation of right postcentral/supramarginal gyrus, and greater connectivity between the caudate and this same anterior parietal region. The results of this study extend previous investigations by demonstrating compromised function of the caudate and connected prefrontal regions in HIV during cognition. This disruption of fronto-striatal circuitry likely precedes the development of cognitive impairment in HIV.

Antisense in vivo knockdown of synaptotagmin I by HVJ-liposome mediated gene transfer attenuates ischemic brain damage in neonatal rats.

Synaptic release of the excitatory amino acid glutamate is considered as an important mechanism in the pathogenesis of ischemic brain damage in neonates. Synaptotagmin I is one of exocytosis-related proteins at nerve terminals and considered to accelerate the exocytosis of synaptic vesicles by promoting fusion between the vesicles and plasma membrane. To test the possibility that antisense in vivo knockdown of synaptotagmin I modulates the exocytotic release of glutamate, thus suppressing the excitotoxic intracellular processes leading to neuronal death following ischemia in the neonatal brain, we injected antisense oligodeoxynucleotides (ODNs) targeting synaptotagmin I (0.3 (AS), 0.15 (0.5 AS), or 0.03 microg (0.1 AS), or vehicle) into the lateral ventricles of 7-day-old rats by using a hemagglutinating virus of Japan (HVJ)-liposome mediated gene transfer technique. At 10 days of age, these rats were subjected to an electrical coagulation of the right external and internal carotid arteries, then the insertion of a solid nylon thread into the right common carotid artery toward the ascending aorta up to 10-12 mm from the upper edge of the sternocleidomastoid muscle. Cerebral ischemia was induced by clamping the left external and internal carotid arteries with a clip, and ended by removing the clip 2h later. Twenty-four hours after the end of ischemia, the extent of ischemic brain damage was neuropathologically and quantitatively evaluated in the neocortex and striatum. While the relative volume of damage in the cerebral cortex and striatum of the vehicle group was extended to 40% and 13.7%, respectively, that in the AS group was significantly reduced to 4.8% and 0.6%. In the 0.5 AS group, the relative volume of ischemic damage in the cerebral cortex and striatum was reduced to 20.5% and 15.4%, respectively, and the difference between the 0.5 AS group and vehicle group was statistically significant in the neocortex, but not in the striatum. These results indicated that antisense in vivo knockdown of synaptotagmin I successfully attenuated ischemic brain damage in neonatal rats and that the effect was dose-dependent. It was also suggested that this treatment was more effective in the neocortex than in the striatum in neonatal rats.

Efficient gene transfer via retrograde transport in rodent and primate brains using a human immunodeficiency virus type 1-based vector pseudotyped with rabies virus glycoprotein.

The primate lentiviral vector system based on human immunodeficiency virus type 1 (HIV-1) has been used for a wide range of gene therapy trials in animal models. Axonal transport in the retrograde direction, which is observed with some viral vectors, confers a considerable advantage to gene transfer into neuronal cell bodies that are localized in regions remote from the injection site of the vectors. However, retrograde axonal transport of the HIV-1-based lentiviral vector pseudotyped with vesicular stomatitis virus glycoprotein is reported to be inefficient. In the present study, we developed an efficient gene transfer system through retrograde transport in the brain with the HIV-1-based vector pseudotyped with rabies virus glycoprotein (RV-G). Injection of the RV-G-pseudotyped HIV-1 vector into the dorsal striatum of mice yielded an increase in gene transfer into neuronal populations in the cerebral cortex, thalamus, and ventral midbrain, each of which innervates the striatum. In addition, injection of the RV-G-pseudotyped vector into the monkey striatum (putamen) resulted in highly efficient transfer into neurons in the ventral midbrain (nigrostriatal dopamine neurons). Our results indicate that pseudotyping of the HIV-1 vector with RV-G enhances the efficiency of gene transfer through retrograde axonal transport in both mouse and monkey brains. This primate lentiviral vector system will provide a powerful approach to gene therapy for neurological and neurodegenerative diseases by means of enhanced retrograde transport.

Differential characteristics of HIV-based versus SIV-based lentiviral vector systems: Gene delivery to neurons and axonal transport of expressed gene.

The differential characteristics of lentiviral vectors based on human and simian immunodeficiency viruses (HIV and SIV) were investigated in rats and monkeys. Each vector was injected into the striatum, and the expression patterns of the marker gene green fluorescent protein (GFP) were analyzed in the basal ganglia. With respect to the capability of gene delivery to neural cells, the HIV-based vector exhibited a higher tropism to neurons than to astroglias in the striatum, and vice versa for the SIV-based vector. The preferential direction of axonal transport of striatally expressed GFP was also examined in the present study. The HIV-based vector allowed for both anterograde transport via the striatopallidal and striatonigral pathways and retrograde transport via the nigrostriatal pathway. The GFP labeling of axon terminals through anterograde transport was apparent regardless of the animal species, while that of neuronal cell bodies through retrograde transport was much more prominent in monkeys than in rats. As for the SIV-based vector, on the other hand, evidence for anterograde transport was obtained much more markedly in monkeys than in rats, and only weak or no retrograde transport occurred in either monkeys or rats. Our results indicate that HIV-based, but not SIV-based, lentiviral vectors possess the high tropism to neurons and permit retrograde transport of an expressed gene, especially in primates. The latter property might carry a potential benefit in gene therapy for Parkinson's disease, as stereotaxic injections of the vectors could be performed into the striatum, spatially larger than the substantia nigra, with greater certainty.

Local dopamine production in the dorsal striatum restores goal-directed behavior in dopamine-deficient mice.

To determine whether dopamine signaling in the dorsal striatum is sufficient for performance of goal-directed behaviors, local dopamine production was restored in the dorsal striatum of dopamine-deficient (DD) mice through viral-mediated gene therapy. Virally rescued DD (vrDD) mice were tested for learning of an appetitive T-maze task designed to measure goal-directed behavior. The results indicate that in contrast with the performance of DD mice that have dysregulated dopamine signaling, vrDD mice were able to perform the T-maze task and reverse their behavior as well as sham-operated control mice. The authors conclude that finely tuned dopaminergic signaling within the dorsal striatum is sufficient for performance of goal-directed behavior.

Nigral injection of antisense oligonucleotides to synaptotagmin I using HVJ-liposome vectors causes disruption of dopamine release in the striatum and impaired skill learning.

To produce an animal model of a dopa-responsive motor disorder with depletion of dopamine (DA) release in the striatum by dysfunction of the transmitter release machinery of the nigrostriatal DA system, we performed an intra-nigral injection of an HVJ-liposome gene transfer vector containing antisense oligodeoxynucleotides (ODNs) against synaptotagmin I (SytI), a key regulator of Ca(2+)-dependent exocytosis and endocytosis in adult rats. A unilateral intra-nigral injection of HVJ-liposome vectors containing antisense ODNs against SytI (syt-AS) caused a moderate disruption of methamphetamine-induced release of DA in the treated side of the striatum, while the syt-AS treatment did not affect physiological release of DA in the treated striatum. A bilateral intra-nigral injection of HVJ-liposome vectors containing syt-AS induced an impairment of the striatal DA-mediated acquisition of skilled behavior in a rotarod task without any deficits in general motor functions, such as spontaneous locomotor activity, motor adjusting steps, equilibrium function, or muscle strength. These findings suggest that an intra-nigral treatment with HVJ-liposome vectors containing syt-AS may cause a long-lasting nigral knockdown of SytI which, in turn, leads to a moderate dysfunction of the DA release machinery in the terminals of the nigrostriatal DA system and a subsequent mild depletion of DA release in the striatum.

Δ9-Tetrahydrocannabinol (Δ9-THC) Promotes Neuroimmune-Modulatory MicroRNA Profile in Striatum of Simian Immunodeficiency Virus (SIV)-Infected Macaques.

Cannabinoid administration before and after simian immunodeficiency virus (SIV)-inoculation ameliorated disease progression and decreased inflammation in male rhesus macaques. Δ9-tetrahydrocannabinol (Δ9-THC) did not increase viral load in brain tissue or produce additive neuropsychological impairment in SIV-infected macaques. To determine if the neuroimmunomodulation of Δ9-THC involved differential microRNA (miR) expression, miR expression in the striatum of uninfected macaques receiving vehicle (VEH) or Δ9-THC (THC) and SIV-infected macaques administered either vehicle (VEH/SIV) or Δ9-THC (THC/SIV) was profiled using next generation deep sequencing. Among the 24 miRs that were differentially expressed among the four groups, 16 miRs were modulated by THC in the presence of SIV. These 16 miRs were classified into four categories and the biological processes enriched by the target genes determined. Our results indicate that Δ9-THC modulates miRs that regulate mRNAs of proteins involved in 1) neurotrophin signaling, 2) MAPK signaling, and 3) cell cycle and immune response thus promoting an overall neuroprotective environment in the striatum of SIV-infected macaques. This is also reflected by increased Brain Derived Neurotrophic Factor (BDNF) and decreased proinflammatory cytokine expression compared to the VEH/SIV group. Whether Δ9-THC-mediated modulation of epigenetic mechanisms provides neuroprotection in other regions of the brain and during chronic SIV-infection remains to be determined.

Neurotrophic factor expression after CNS viral injury produces enhanced sensitivity to psychostimulants: potential mechanism for addiction vulnerability.

Hypothesized risk factors for psychostimulant, amphetamine, and cocaine abuse include dopamine (DA) receptor polymorphisms, HIV infection, schizophrenia, drug-induced paranoias, and movement disorders; however, the molecular, cellular, and biochemical mechanisms that predispose to drug sensitivity or drive the development of addiction are incompletely understood. Using the Borna disease rat, an animal model of viral-induced encephalopathy wherein sensitivity to the locomotor and stereotypic behavioral effects of d-amphetamine and cocaine is enhanced (Solbrig et al., 1994, 1998), we identify a specific neurotrophin expression pattern triggered by striatal viral injury that increases tyrosine hydroxylase activity, an early step in DA synthesis, to produce a phenotype of enhanced amphetamine sensitivity. The reactive neurotrophin pattern provides a molecular framework for understanding how CNS viral injury, as well as other CNS adaptations producing similar growth factor activation profiles, may influence psychostimulant sensitivity.

Enhanced long-term expression from helper virus-free HSV-1 vectors packaged in the presence of deletions in genes that modulate the function of VP16, U L 46 and U L 47.

Herpes simplex virus (HSV-1) gene expression is hypothesized to shut off recombinant gene expression from HSV-1 vectors, but in a helper virus-free HSV-1 vector system, a number of promoters support only short-term expression. Thus paradoxically, recombinant gene expression remains short-term in the absence of almost all (approximately 99%) of the HSV-1 genome. To resolve this paradox, we hypothesize that specific HSV-1 proteins that affect the virion can shut off recombinant gene expression. In an earlier study, we examined the effects on recombinant gene expression of five different proteins that affect the HSV-1 virion. We found that vectors packaged in the presence of mutated vhs or U S 11 exhibited minimal changes in gene expression, vectors packaged in the presence of a mutated U S 3 supported improved gene transfer (numbers of cells at 4 days), and vectors packaged in the presence of mutated U L 13 or VP16 supported improved long-term expression. The capability of the VP16 transcriptional complex to reduce gene expression deserves additional study because VP16 is a powerful enhancer that interacts with a number of cellular and viral proteins. In particular, U L 46 and U L 47 are known to modulate the effects of VP16 on immediate early promoters. In this study, we examined expression from a HSV-1 vector that contains a neuronal-specific promoter and was packaged in the presence of deletions in U L 46, or U L 47, or both U L 46 and U L 47. In the rat striatum, each of these vector stocks supported both improved gene transfer (numbers of cells at 4 days) and improved long-term expression (2 months). Vectors packaged in the presence of a deletion in both U L 46 and U L 47 supported larger improvements in gene expression compared to vectors packaged in the presence of deletions in either gene alone. The implications of these results for strategies to improve long-term expression are discussed.

Infantile bilateral striatal necrosis associated with human herpes virus-6 (HHV-6) infection.

A 1-year-old female with acute bilateral striatal necrosis secondary to exanthema subitum associated with human herpesvirus 6 (HHV-6) infection is reported. The patient was previously healthy. She presented with progressive neurologic signs of oral dyskinesia and involuntary movements, after suffering from exanthema subitum. Initial magnetic resonance imaging (MRI) demonstrated abnormal signals in the bilateral striatal regions. In addition, the serum HHV-6 IgM class antibody level was significantly increased. The patient is thought to be the first case of HHV-6 infection related infantile bilateral striatal necrosis (IBSN).