HIV-associated Neurological Disorders Research Articles

Characterization of HIV-1 Infection in Microglia-Containing Human Cerebral Organoids.

The achievement of an HIV cure is dependent on the eradication or permanent silencing of HIV-latent viral reservoirs, including the understudied central nervous system (CNS) reservoir. This requires a deep understanding of the molecular mechanisms of HIV’s entry into the CNS, latency establishment, persistence, and reversal. Therefore, representative CNS culture models that reflect the intercellular dynamics and pathophysiology of the human brain are urgently needed in order to study the CNS viral reservoir and HIV-induced neuropathogenesis. In this study, we characterized a human cerebral organoid model in which microglia grow intrinsically as a CNS culture model to study HIV infection in the CNS. We demonstrated that both cerebral organoids and isolated organoid-derived microglia (oMG), infected with replication-competent HIVbal reporter viruses, support productive HIV infection via the CCR5 co-receptor. Productive HIV infection was only observed in microglial cells. Fluorescence analysis revealed microglia as the only HIV target cell. Susceptibility to HIV infection was dependent on the co-expression of microglia-specific markers and the CD4 and CCR5 HIV receptors. Altogether, this model will be a valuable tool within the HIV research community to study HIV–CNS interactions, the underlying mechanisms of HIV-associated neurological disorders (HAND), and the efficacy of new therapeutic and curative strategies on the CNS viral reservoir.

Рання діагностика ВІЛ-асоційованих неврологічних порушень як актуальна проблема в практиці невролога

В статті подана актуальність вивчення питань ранньої діагностики ВІЛ-асоційованих уражень нервової системи в практиці невролога, надана класифікація первинних і вторинних ВІЛ-асоційованих уражень нервової системи, їх кодування згідно з МКХ-10, патерн діагностичних заходів, підходів до терапії. Подано аналіз нормативних документів для допомоги лікарю-неврологу в вирішенні питань щодо ранньої діагностики, тактики ведення даної категорії хворих.

HIV-1 Tat induced microglial EVs leads to neuronal synaptodendritic injury: microglia-neuron cross-talk in NeuroHIV.

Activation of microglial NLRP3 inflammasome is an essential contributor to neuroinflammation underlying HIV-associated neurological disorders (HAND). Under pathological conditions, microglia-derived-EVs (MDEVs) can affect neuronal functions by delivering neurotoxic mediators to recipient cells. However, the role of microglial NLRP3 in mediating neuronal synaptodendritic injury has remained unexplored to date. In the present study, we sought to assess the regulatory role of HIV-1 Tat induced microglial NLRP3 in neuronal synaptodendritic injury. We hypothesized that HIV-1 Tat mediated microglia EVs carrying significant levels of NLRP3 contribute to the synaptodendritic injury, thereby affecting the maturation of neurons. To understand the cross-talk between microglia and neuron, we isolated EVs from BV2 and human primary microglia (HPM) cells with or without NLRP3 depletion using siNLRP3 RNA. EVs were isolated by differential centrifugation, characterized by ZetaView nanoparticle tracking analysis, electron microscopy, and western blot analysis for exosome markers. Purified EVs were exposed to primary rat neurons isolated from E18 rats. Along with green fluorescent protein (GFP) plasmid transfection, immunocytochemistry was performed to visualize neuronal synaptodendritic injury. Western blotting was employed to measure siRNA transfection efficiency and the extent of neuronal synaptodegeneration. Images were captured in confocal microscopy, and subsequently, Sholl analysis was performed for analyzing dendritic spines using neuronal reconstruction software Neurolucida 360. Electrophysiology was performed on hippocampal neurons for functional assessment. Our findings demonstrated that HIV-1 Tat induced expression of microglial NLRP3 and IL1β, and further that these were packaged in microglial exosomes (MDEV) and were also taken up by the neurons. Exposure of rat primary neurons to microglial Tat-MDEVs resulted in downregulation of synaptic proteins- PSD95, synaptophysin, excitatory vGLUT1, as well as upregulation of inhibitory proteins- Gephyrin, GAD65, thereby implicating impaired neuronal transmissibility. Our findings also showed that Tat-MDEVs not only caused loss of dendritic spines but also affected numbers of spine sub-types- mushroom and stubby. Synaptodendritic injury further affected functional impairment as evidenced by the decrease in miniature excitatory postsynaptic currents (mEPSCs). To assess the regulatory role of NLRP3 in this process, neurons were also exposed to Tat-MDEVs from NLRP3 silenced microglia. Tat-MDEVs from NLRP3 silenced microglia exerted a protective role on neuronal synaptic proteins, spine density as well as mEPSCs. In summary, our study underscores the role of microglial NLRP3 as an important contributor to Tat-MDEV mediated synaptodendritic injury. While the role of NLRP3 in inflammation is well-described, its role in EV-mediated neuronal damage is an interesting finding, implicating it as a target for therapeutics in HAND.

Luminescent PLGA Nanoparticles for Delivery of Darunavir to the Brain and Inhibition of Matrix Metalloproteinase-9, a Relevant Therapeutic Target of HIV-Associated Neurological Disorders.

Human immunodeficiency virus (HIV) can independently replicate in the central nervous system (CNS) causing neurocognitive impairment even in subjects with suppressed plasma viral load. The antiretroviral drug darunavir (DRV) has been approved for therapy of HIV-infected patients, but its efficacy in the treatment of HIV-associated neurological disorders (HAND) is limited due to the low penetration through the blood–brain barrier (BBB). Therefore, innovations in DRV formulations, based on its encapsulation in optically traceable nanoparticles (NPs), may improve its transport through the BBB, providing, at the same time, optical monitoring of drug delivery within the CNS. The aim of this study was to synthesize biodegradable polymeric NPs loaded with DRV and luminescent, nontoxic carbon dots (C-Dots) and investigate their ability to permeate through an artificial BBB and to inhibit in vitro matrix metalloproteinase-9 (MMP-9) that represents a factor responsible for the development of HIV-related neurological disorders. Biodegradable poly(lactic-co-glycolic) acid (PLGA)-based nanoformulations resulted characterized by an average hydrodynamic size less than 150 nm, relevant colloidal stability in aqueous medium, satisfactory drug encapsulation efficiency, and retained emitting optical properties in the visible region of the electromagnetic spectrum. The assay on the BBB artificial model showed that a larger amount of DRV was able to cross BBB when incorporated in the PLGA NPs and to exert an enhanced inhibition of matrix metalloproteinase-9 (MMP-9) expression levels with respect to free DRV. The overall results reveal the great potential of this class of nanovectors of DRV for an efficacious treatment of HANDs.

Neurological manifestation with special reference to HIV-associated neurocognitive disorder (HAND) among people on anti-retroviral treatment in India.

The neurological manifestations and their severity in patients on antiretroviral treatment (ART) are currently unexplained. ‎We aimed at studying the prevalence of HIV Associated Neurological Disorders (HAND) among people on antiretroviral treatment, using the International HIV Dementia Scale (IHDS). A predesigned and pretested proforma including the International HIV Dementia Scale (IHDS) was administered to 100 HIV patients attending to ART center of KIMS teaching Hospital (Koppal, Karnataka) from January 2020 to March 2020. The data was analyzed SPSS version 15 software. Descriptive statistics were used for demographic characteristics. The Student's t-test and chi-square test methods were applied to determine the relationship between qualitative characteristics. The prevalence was found to be 59%. Out of 100, 57 HIV patients scored less than 10 whereas 43 HIV patients scored ≥10 on the IHDS scale. The mean age of the study population was 39.14 ±13.01 years; the total IHDS score was 9.96±1.53 and the CD4 count was 427.91±226.0. This study demonstrated that the patients with CD4 count more than 350 (i.e., 63.60%) had a better IHDS score. Neurocognitive disorder was found to be more common than anticipated. All ICTC Centers need to consider assessing HIV-associated neurocognitive disability (HAND), and the International HIV Dementia Scale (IHDS) as one instrument for such assessment.

Increased IL-6 expression precedes reliable viral detection in the rhesus macaque brain during acute SIV infection.

Knowledge of immune activation in the brain during acute HIV infection is crucial for the prevention and treatment of HIV-associated neurological disorders. We determined regional brain (basal ganglia, thalamus, and frontal cortex) immune and virological profiles at 7 and 14 days post infection (dpi) with SIVmac239 in rhesus macaques. The basal ganglia and thalamus had detectable viruses earlier (7 dpi) than the frontal cortex (14 dpi) and contained higher quantities of viruses than the latter. Increased immune activation of astrocytes and significant infiltration of macrophages in the thalamus at 14 dpi coincided with elevated plasma viral load, and SIV colocalized only within macrophages. RNA signatures of proinflammatory responses, including IL-6, were detected at 7 dpi in microglia and interestingly, preceded reliable detection of virus in tissues and were maintained in the chronically infected macaques. Countering the proinflammatory response, the antiinflammatory response was not detected until increased TGF-β expression was found in perivascular macrophages at 14 dpi. But this response was not detected in chronic infection. Our data provide evidence that the interplay of acute proinflammatory and antiinflammatory responses in the brain likely contributed to the overt neuroinflammation, where the immune activation preceded reliable viral detection.

Клинический случай диагностики поздней стадии ВИЧ-инфекции у подростка с хореей

ВИЧ-инфекция среди возможных этиологических факторов неврологической патологии пока рассматривается редко, что приводит к поздней диагностике заболевания и несвоевременному началу специфической терапии. Неврологические проявления заболевания могут возникать в связи с прямым воздействием ВИЧ на нервную систему, оппортунистическими инфекциями и злокачественными новообразованиями, нейротоксичными эффектами антиретровирусного лечения и другими системными осложнениями. ВИЧ-ассоциированные неврологические расстройства вариабельны и представлены нейрокогнитивными нарушениями, энцефалопатией, миелопатией, полинейропатией, асептическим менингитом (менингоэнцефалитом). ВИЧ-энцефалопатия у детей проявляется в форме эмоциональных, когнитивных, двигательных, речевых нарушений. У взрослых больных как возможный клинический вариант ВИЧ-энцефалопатии рассматривается синдром хореи. В доступной литературе мы не встретили сообщений о развитии хорееподобного синдрома у ВИЧ-инфицированных детей. Описанный клинический случай демонстрирует диагностику поздней стадии ВИЧ-инфекции у ребенка 13 лет с синдромом хореи. Представленное клиническое наблюдение демонстрирует сложности диагностики ВИЧ-энцефалопатии у ребенка, что было связано с редким проявлением данного заболевания в детском возрасте в виде генерализованных гиперкинезов, а также с сокрытием матерью анамнестических данных о наличии у нее ВИЧ-инфекции. Таким образом, у детей с хореей диагноз возможен только при исключении заболеваний, ее вызывающих, а именно острой ревматической лихорадки, системного заболевания соединительной ткани, демиелинизирующих заболеваний, объемно-органической патологии центральной нервной системы, болезни Вильсона — Коновалова, а также ВИЧ-инфекции.

Ultradeep HIV-1 Proviral Envelope Sequencing Reveals Complex Population Structure within and between Brain and Splenic Tissues

Understanding tissue-based HIV-1 proviral population structure is important for improving treatment strategies for individuals with HIV-associated neurological disorders (HAND). Previous analyses have revealed HIV-1 envelope (env) population structure between brain and peripheral tissues as well as Env functional differences, especially in individuals with HAND. Furthermore, population structure has been detected among different anatomical locations in the brain itself, although such patterns are inconsistent across individuals and less strongly associated with the presence/absence of HAND. Here, we utilized the Pacific Biosciences single-molecule real-time (SMRT) high-throughput technology to generate thousands of sequences for each tissue, along with phylogenetic and distance-based analyses, to investigate env sequences from paired brain and spleen samples from eight individuals with/without HAND. To account for the high error rate associated with SMRT sequencing, we used a clustering approach to identify high-quality consensus sequences representative of ≥10 reads ("HQCS10"). In parallel, we characterized variable regions from nonclustered sequences to identify potential functional differences. We found evidence for significant population structure between brain and spleen tissues, as well as among brain tissues and within the same brain tissue, in individuals both with and without HAND. Variable region analysis showed differences in length and charge among brain and nonbrain tissues as well as within the brain, suggesting possible functional differences. Our results demonstrate the complexity of HIV-1 env structure/gene flow among tissues and support the concept that selective pressures in different tissue microenvironments drive viral evolution and adaptation. IMPORTANCE Understanding the evolution of HIV-1 in the brain compared to other tissues is important for improving treatment strategies for individuals with HIV-associated neurological disorders (HAND). We utilized high-throughput sequencing technology to generate thousands of full-length env sequences from paired brain and spleen samples from eight individuals with/without HAND. We found significant viral population structure for participants both with and without HAND, providing robust evidence for the brain as a compartmentalized tissue and potentially a viral reservoir. We also found striking genetic differences between virus populations, even from the same tissue, suggesting the potential for functional differences and the possibility for multiple evolutionary pathways that result in similar tropisms and/or other tissue-adapted characteristics. Our results demonstrate the complexity of viral population structure within the brain and suggest that analysis of peripheral blood samples alone may not be fully informative with respect to improving strategies to treat or eradicate HIV-1.

Advances in the Experimental Models of HIV-Associated Neurological Disorders.

Involvement of the central nervous system (CNS) in HIV-1 infection is commonly associated with neurological disorders and cognitive impairment, commonly referred to as HIV-associated neurocognitive disorders (HAND). Severe and progressive neurocognitive impairment is rarely observed in the post-cART era; however, asymptomatic and mild neurocognitive disorders still exist, despite viral suppression. Additionally, comorbid conditions can also contribute to the pathogenesis of HAND. In this review, we summarize the characterization of HAND, factors contributing, and the functional impairments in both preclinical and clinical models. Specifically, we also discuss recent advances in the animal models of HAND and in in vitro cultures and the potential role of drugs of abuse in this model system of HAND. Potential peripheral biomarkers associated with HAND are also discussed. Overall, this review identifies some of the recent advances in the field of HAND in cell culture studies, animal models, clinical findings, and the limitations of each model system, which can play a key role in developing novel therapeutics in the field.

Alzheimer's-Like Pathology at the Crossroads of HIV-Associated Neurological Disorders.

Despite the widespread success of combined antiretroviral therapy (cART) in suppressing viremia, the prevalence of human immunodeficiency virus (HIV)-associated neurological disorders (HAND) and associated comorbidities such as Alzheimer’s disease (AD)-like symptomatology is higher among people living with HIV. The pathophysiology of observed deficits in HAND is well understood. However, it has been suggested that it is exacerbated by aging. Epidemiological studies have suggested comparable concentrations of the toxic amyloid protein, amyloid-β42 (Aβ42), in the cerebrospinal fluid (CSF) of HAND patients and in the brains of patients with dementia of the Alzheimer’s type. Apart from abnormal amyloid-β (Aβ) metabolism in AD, a better understanding of the role of similar pathophysiologic processes in HAND could be of substantial value. The pathogenesis of HAND involves either the direct effects of the virus or the effect of viral proteins, such as Tat, Gp120, or Nef, as well as the effects of antiretrovirals on amyloid metabolism and tauopathy, leading, in turn, to synaptodendritic alterations and neuroinflammatory milieu in the brain. Additionally, there is a lack of knowledge regarding the causative or bystander role of Alzheimer’s-like pathology in HAND, which is a barrier to the development of therapeutics for HAND. This review attempts to highlight the cause–effect relationship of Alzheimer’s-like pathology with HAND, attempting to dissect the role of HIV-1, HIV viral proteins, and antiretrovirals in patient samples, animal models, and cell culture model systems. Biomarkers associated with Alzheimer’s-like pathology can serve as a tool to assess the neuronal injury in the brain and the associated cognitive deficits. Understanding the factors contributing to the AD-like pathology associated with HAND could set the stage for the future development of therapeutics aimed at abrogating the disease process.

Neuromodulation of BAG co-chaperones by HIV-1 viral proteins and H2O2: implications for HIV-associated neurological disorders

Despite increasing numbers of aged individuals living with HIV, the mechanisms underlying HIV-associated neurological disorders (HANDs) remain elusive. As HIV-1 pathogenesis and aging are characterized by oxidative stress as well as altered protein quality control (PQC), reactive oxygen species (ROS) themselves might constitute a molecular mediator of neuronal PQC by modulating BCL-2 associated athanogene (BAG) family members. Present results reveal H2O2 replicated and exacerbated a reduction in neuronal BAG3 induced by the expression of HIV-1 viral proteins (i.e., Tat and Nef), while also causing an upregulation of BAG1. Such a reciprocal regulation of BAG3 and BAG1 levels was also indicated in two animal models of HIV, the doxycycline-inducible Tat (iTat) and the Tg26 mouse. Inhibiting oxidative stress via antioxidants in primary culture was capable of partially preserving neuronal BAG3 levels as well as electrophysiological functioning otherwise altered by HIV-1 viral proteins. Current findings indicate HIV-1 viral proteins and H2O2 may mediate neuronal PQC by exerting synergistic effects on complementary BAG family members, and suggest novel therapeutic targets for the aging HIV-1 population.

Astrocytes & Astrocyte derived Extracellular Vesicles in Morphine Induced Amyloidopathy: Implications for Cognitive Deficits in Opiate Abusers.

While opiates like morphine play a major role in the pharmacotherapy for the control of pain associated with various diseases, paradoxically, their long-term use is associated with cognitive impairments. Furthermore, morphine administration has been shown to result in neuronal synaptodendritic injury in rodent brains, leading to neurodegeneration. We recently reported the role of astrocytes as contributors of amyloidosis associated with HIV-associated neurological disorders. Herein we hypothesize that morphine could induce astrocytic amyloidosis, which, in turn, could be disseminated to various regions in the brain by astrocyte-derived EVs (ADEVs). In this study we demonstrate brain region-specific up-regulation of astrocytic amyloids in morphine dependendent rhesus macaques. In addition, herein we also demonstrate increased expression of β-site cleaving enzyme (BACE1), APP, and Aβ in human primary astrocytes (HPAs) exposed to morphine. Mechanisms involved in this process included the up-regulation of hypoxia-inducible factor (HIF-1α), its translocation and binding to the promoter of BACE1, leading to increased BACE1 activity and, generation of Aβ 1-42. Gene silencing approaches confirmed the regulatory role of HIF-1α in BACE1 mediated amyloidosis leading to astrocyte activation and neuroinflammation. We next sought to assess whether morphine-stimulated ADEVs could carry amyloid cargoes. Results showed that morphine exposure induced the release of morphine-ADEVs, carrying amyloids. Interestingly, silencing HIF-1α in astrocytes not only reduced the numbers of ADEV released, but also the packaging of amyloid cargos in the ADEVs. These findings were further validated in brain derived EVs (BEVs) isolated from macaques, wherein it was shown that BEVs from morphine-dependent macaques, carried varieties of amyloid cargoes including the cytokine IL-1β. This is the first report implicating the role of HIF-1α-BACE1 axis in morphine-mediated induction of astrocytic amyloidosis, leading, in turn, to neuroinflammation and release of the amyloid cargoes via ADEVs. These findings set the groundwork for the future development of therapeutic strategies for targeting cognitive deficits in chronic opiate users.

Unraveling neuroHIV in the Presence of Substance Use Disorders.

This special issue contains 10 invited review papers that highlighted and extended the presentations at the NIDA-sponsored workshop "Unraveling NeuroAIDS in the Presence of Substance Use Disorders" at the 25th Society on NeuroImmune Pharmacology conference in 2019. The topics covered by these papers focused on the interactive, additive or synergistic effects of substance use disorders (SUD) with HIV infection on the immune system and onneuropathogenesis. These papers reviewed four categories of substances of abuse (opioids, tobacco, stimulants, and cannabis) and how comorbid HIV infection (including models with HIV proteins, HIV transgenic rodent models and SIV) might further impact the dysregulated dopaminergic and immune systems, and the subsequent neuropathogenesis and behavioral disorders known as HIV-associated neurological disorders (HAND). These reviews provided detailed background knowledge regarding how each of theseaddictive substances and HIV individually or collectively affected the immune system at the cellular, molecular and system levels, and the subsequent clinical and behavioral outcomes. The authors also identified gaps, confounds or constraints in the current disease models and approaches, and proposed future research directions.

Emerging Role of Nef in the Development of HIV Associated Neurological Disorders.

Despite adherence to treatment, individuals living with HIV have an increased risk for developing cognitive impairments, referred to as HIV-associated neurological disorders (HAND). Due to continued growth in the HIV population, particularly amongst the aging cohort, the neurobiological mechanisms of HAND are increasingly relevant. Similar to other viral proteins (e.g. Tat, Gp120, Vpr), the Negative Factor (Nef) is associated with numerous adverse effects in the CNS as well as cognitive impairments. In particular, emerging data indicate the consequences of Nef may be facilitated by the modulation of cellular autophagy as well as its inclusion into extracellular vesicles (EVs). The present review examines evidence for the molecular mechanisms by which Nef might contribute to neuronal dysfunction underlying HAND, with a specific focus on autophagy and EVs. Based on the these data, we propose an integrated model by which Nef may contribute to underlying neuronal dysfunction in HAND and highlight potentially novel therapeutic targets for HAND. Graphical abstract.

Erratum: Yao et al., "Platelet-Derived Growth Factor B Chain Is a Novel Target Gene of Cocaine-Mediated Notch1 Signaling: Implications for HIV-Associated Neurological Disorders".

Erratum: Yao et al., "Platelet-Derived Growth Factor B Chain Is a Novel Target Gene of Cocaine-Mediated Notch1 Signaling: Implications for HIV-Associated Neurological Disorders".

Mass Spectrometry Imaging Demonstrates the Regional Brain Distribution Patterns of Three First-Line Antiretroviral Drugs.

HIV in the central nervous system (CNS) contributes to the development of HIV-associated neurological disorders (HAND), even with chronic antiretroviral therapy. In order for antiretroviral therapy to be effective in protecting the CNS, these drugs should have the ability to localize in brain areas known to be affected by HIV. Consequently, this study aimed to investigate the localization patterns of three first-line antiretroviral drugs, namely, efavirenz, tenofovir, and emtricitabine, in the rat brain. Liquid chromatography–tandem mass spectrometry (LC–MS/MS) and matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) were utilized to assess the pharmacokinetics and brain spatial distribution of the three drugs. Each drug was administered (50 mg/kg) to healthy female Sprague–Dawley rats via intraperitoneal administration. LC–MS/MS results showed that all three drugs could be delivered into the brain, although they varied in blood–brain barrier permeability. MALDI-MSI showed a high degree of efavirenz localization across the entire brain, while tenofovir localized mainly in the cortex. Emtricitabine distributed heterogeneously mainly in the thalamus, corpus callosum, and hypothalamus. This study showed that efavirenz, tenofovir, and emtricitabine might be a potential drug combination antiretroviral therapy for CNS protection against HAND.

Absence of age-related neurodegenerative changes during SIV infection and treatment in aged macaques

The advent of combined antiretroviral therapy (CART) has changed HIV infection from a lethal disease to a chronic infection. CART has substantially mitigated infection-associated immunosuppression, related opportunistic infections and HIV encephalitis, nevertheless a substantial percentage of infected individuals are afflicted with a spectrum of HIV-associated neurological disorders (HAND). As approximately 45% of HIV-infected subjects in developed countries are over the age of 50, it has been hypothesized that infection may exacerbate age related neurodegenerative processes. We used the nonhuman primate SIV infection model to test whether chronic infection of aged primates, with or without CART, is associated with accelerated age-related neurodegeneration. Two dozen aged macaques (average age 18 years at entry 20 years at the end) were divided into two groups, half infected with SICmac251 and the other half not. After 10 months, half of each of these groups were either treated or not with CART and followed for an additional 6 months. We previously reported the clinical and neurobehavioural outcome. Here we compared the molecular and histologic findings in the four groups. Using a broad spectrum of histological markers, we found no evidence in the macaques of neuropathological changes associated with aging in humans. While the number of animals is small and length of infection limited, this study does not support the hypothesis that lentiviral infection or treatment accelerates age-related neurodegenerative changes in the primate brain.LEARNING OBJECTIVESThis presentation will enable the learner to:1.Explore current theories on the pathogenesis of lentiviral-related neuropathology2.Explain limitations of nonhuman primate models of age-related human brain changes

Rilpivirine as a potential candidate for the treatment of HIV-associated neurocognitive disorders (HAND).

As the HIV epidemic continues to contribute to global morbidity and mortality, the prevalence of HIV-associated neurological disorders (HAND) also continues to be a major concern in infected individuals, despite the widespread use of combination antiretroviral therapy. Therefore, current antiretroviral drugs should be able to reach therapeutic levels in the brain for the treatment of HAND. The brain distribution of the next-generation non-nucleoside reverse transcriptase inhibitor, rilpivirine (RPV) was investigated in healthy female Sprague-Dawley (SD) rats. The presented study involves the use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) to estimate the concentrations of RPV in plasma and brain homogenate samples. The use of matrix-assisted laser desorption/ionization mass spectrometry imaging(MALDI-MSI) provided regional spatial distribution of RPV in brain tissue sections. The localization of RPV was found to be relatively high in the hypothalamus, thalamus and corpus callosum, brain regions known to be associated with neurodegeneration during HAND (including the cerebral cortex). This study has shown that RPV has an excellent blood-brain barrier penetrability. Thus, in combination with other antiretroviral drugs, better central nervous system (CNS) protection against HAND can possibly be achieved.

Plasma neuronal exosomes serve as biomarkers of cognitive impairment in HIV infection and Alzheimer's disease.

Plasma neuronal exosomes serve as biomarkers of cognitive impairment in HIV infection and Alzheimer's disease.

Human Immunodeficiency Virus Type 1 gp120 and Tat Induce Mitochondrial Fragmentation and Incomplete Mitophagy in Human Neurons.

HIV enters the central nervous system (CNS) during the early stages of infection and can cause neurological dysfunction, including neurodegeneration and neurocognitive impairment. The specific autophagy responsible for removal of damaged mitochondria (mitophagy) and mitochondrial dynamics constitute neuronal mitochondrial quality control mechanisms and are impaired in neurodegenerative disorders and numerous other diseases. The release of HIV proteins gp120 and Tat from infected cells is thought to play an important role in HIV-associated neurocognitive disorders (HAND), but the mechanism(s) leading to impairment are poorly understood. Here, we report that exposure of human primary neurons (HPNs) to HIV gp120 and Tat accelerates the balance of mitochondrial dynamics toward fission (fragmented mitochondria) and induces perinuclear aggregation of mitochondria and mitochondrial translocation of dynamin-related protein 1 (DRP1), leading to neuronal mitochondrial fragmentation. HIV gp120 and Tat increased the expression of microtubule-associated protein 1 light chain 3 beta (LC3B) protein and induced selective recruitment of Parkin/SQSTM1 to the damaged mitochondria. Using either a dual fluorescence reporter system expressing monomeric red fluorescent protein and enhanced green fluorescent protein targeted to mitochondria (mito-mRFP-EGFP) or a tandem light chain 3 (LC3) vector (mCherry-EGFP-LC3), both HIV proteins were found to inhibit mitophagic flux in human primary neurons. HIV gp120 and Tat induced mitochondrial damage and altered mitochondrial dynamics by decreasing mitochondrial membrane potential (ΔΨm). These findings indicate that HIV gp120 and Tat initiate the activation and recruitment of mitophagy markers to damaged mitochondria in neurons but impair the delivery of mitochondria to the lysosomal compartment. Altered mitochondrial dynamics associated with HIV infection and incomplete neuronal mitophagy may play a significant role in the development of HAND and accelerated aging associated with HIV infection.IMPORTANCE Despite viral suppression by antiretrovirals, HIV proteins continue to be detected in infected cells and neurologic complications remain common in infected people. Although HIV is unable to infect neurons, viral proteins, including gp120 and Tat, can enter neurons and can cause neuronal degeneration and neurocognitive impairment. Neuronal health is dependent on the functional integrity of mitochondria, and damaged mitochondria are subjected to mitochondrial control mechanisms. Multiple lines of evidence suggest that specific elimination of damaged mitochondria through mitophagy and mitochondrial dynamics play an important role in CNS diseases. Here, we show that in human primary neurons, gp120 and Tat favor the balance of mitochondrial dynamics toward enhanced fragmentation through the activation of mitochondrial translocation of DRP1 to the damaged mitochondria. However, mitophagy fails to go to completion, leading to neuronal damage. These findings support a role for altered mitophagy in HIV-associated neurological disorders and provide novel targets for potential intervention.