HIV-1-associated neurocognitive disorder: epidemiology, pathogenesis, diagnosis, and treatment

Synaptic dysfunction is associated with alterations in the initiation of goal-directed behaviors: Implications for HIV-1-associated apathy

Individuals living with human immunodeficiency virus type 1 (HIV-1) exhibit an increased prevalence of neuropsychiatric comorbities (e.g., apathy) relative to their seronegative counterparts. Given the profound functional consequences associated with apathy, characterizing the multidimensional neuropsychiatric syndrome, and associated neural mechanisms, following chronic HIV-1 viral protein exposure remains a critical need. HIV-1-associated apathy was examined by quantifying goal-directed behaviors, indexed using voluntary wheel running, during the diurnal and nocturnal cycle. Apathetic behaviors in the HIV-1 transgenic (Tg) rat were characterized by a profound decrease in the number of running bouts during both the diurnal and nocturnal cycle, supporting a prominent deficit in the self-initiation of spontaneous behaviors. Additionally, HIV-1 Tg animals exhibited a decreased reinforcing efficacy of voluntary wheel running during the nocturnal cycle. Following the completion of voluntary wheel running, synaptic dysfunction in medium spiny neurons (MSNs) of the nucleus accumbens core (NAcc) was examined as a potential neural mechanism underlying HIV-1-associated apathy. HIV-1 Tg animals displayed prominent synaptic dysfunction in MSNs of the NAcc, characterized by enhanced dendritic branching complexity and a population shift towards an immature dendritic spine phenotype relative to control animals. Synaptic dysfunction, which accounted for 42.0% to 68.5% of the variance in the number of running bouts, was strongly associated with the self-initiation of spontaneous behaviors. Establishment of the relationship between synaptic dysfunction and apathy affords a key target for the development of novel therapeutics and cure strategies for affective alterations associated with HIV-1.

Animal models for studies of HIV-1 brain reservoirs

The HIV-1 often evades a robust antiretroviral-mediated immune response, leading to persistent infection within anatomically privileged sites including the CNS. Continuous low-level infection occurs in the presence of effective antiretroviral therapy (ART) in CD4+ T cells and mononuclear phagocytes (MP; monocytes, macrophages, microglia, and dendritic cells). Within the CNS, productive viral infection is found exclusively in microglia and meningeal, perivascular, and choroidal macrophages. MPs serve as the principal viral CNS reservoir. Animal models have been developed to recapitulate natural human HIV-1 infection. These include nonhuman primates, humanized mice, EcoHIV, and transgenic rodent models. These models have been used to study disease pathobiology, antiretroviral and immune modulatory agents, viral reservoirs, and eradication strategies. However, each of these models are limited to specific component(s) of human disease. Indeed, HIV-1 species specificity must drive therapeutic and cure studies. These have been studied in several model systems reflective of latent infections, specifically in MP (myeloid, monocyte, macrophages, microglia, and histiocyte cell) populations. Therefore, additional small animal models that allow productive viral replication to enable viral carriage into the brain and the virus-susceptible MPs are needed. To this end, this review serves to outline animal models currently available to study myeloid brain reservoirs and highlight areas that are lacking and require future research to more effectively study disease-specific events that could be useful for viral eradication studies both in and outside the CNS.

3D Genome Plasticity in Normal and Diseased Neurodevelopment

Non-random spatial organization of the chromosomal material inside the nuclei of brain cells emerges as an important regulatory layer of genome organization and function in health and disease. Here, we discuss how integrative approaches assessing chromatin in context of the 3D genome is providing new insights into normal and diseased neurodevelopment. Studies in primate (incl. human) and rodent brain have confirmed that chromosomal organization in neurons and glia undergoes highly dynamic changes during pre- and early postnatal development, with potential for plasticity across a much wider age window. For example, neuronal 3D genomes from juvenile and adult cerebral cortex and hippocampus undergo chromosomal conformation changes at hundreds of loci in the context of learning and environmental enrichment, viral infection, and neuroinflammation. Furthermore, locus-specific structural DNA variations, such as micro-deletions, duplications, repeat expansions, and retroelement insertions carry the potential to disrupt the broader epigenomic and transcriptional landscape far beyond the boundaries of the site-specific variation, highlighting the critical importance of long-range intra- and inter-chromosomal contacts for neuronal and glial function.

Comprehensive assessment of neurocognitive function, inflammation markers, and adiposity in treated HIV and control

To compare the neurocognitive scores between persons living with human immunodeficiency virus (PLWH) and persons without human immunodeficiency virus (HIV) and assess the relationship between neurocognition, HIV status and variables, inflammation, and body composition measures. Cross-sectional study involving 225 participants (126 PLWH on antiretroviral therapy [ART] and 99 persons without HIV). For the first time in HIV, we used Cognivue®, an food and drug administration (FDA)-approved computer-based test to assess cognitive function. The test was calibrated to individuals' unique cognitive ability and measured 6 cognitive domains and 2 performance parameters. Markers of inflammation, immune activation, insulin resistance, and body fat composition (using dual-energy X-ray absorptiometry scan) were collected. Classical t tests, chi-square tests, and spearman correlations were used to compare and explore relationships between variables. Inverse probability weighting adjusted average treatment effect models were performed to evaluate the differences between PLWH and persons without HIV, adjusting for age, race, sex, and heroin use. Overall, 64% were male, 46% were Black, with a mean age of 43 years. Among PLWH, 83% had an undetectable HIV-1 RNA level (≤20 copies/mL). Compared persons without HIV, PLWH performed poorer across 4 domains: visuospatial (P = .035), executive function (P = .029), naming/language (P = .027), and abstraction (P = .018). In addition, PLWH had a significantly longer processing speed time compared to controls (1686.0 ms vs 1606.0 ms [P = .007]). In PLWH, lower cognitive testing domain scores were associated with higher inflammatory markers (high sensitivity C-reactive protein [hsCRP]) and with higher total fat and visceral adipose tissue (P < .05). Neurocognitive impairment (NCI) in HIV is associated with inflammation and total and central adiposity.

Sexual Minority Stress and Cellular Aging in Methamphetamine-Using Sexual Minority Men With Treated HIV

OBJECTIVE

Sexual minority men (e.g., gay, bisexual, and other men who have sex with men) experience stigma and sexual minority stress, which are theorized to drive negative health outcomes. Sexual minority men with treated HIV display persistent immune dysregulation, which could be amplified by sexual minority stress responses to potentiate cellular aging.

METHODS

This cross-sectional study included 52 sexual minority men living with HIV who had undetectable viral load (<40 copies/mL) and biologically confirmed recent methamphetamine use. Participants completed measures assessing sexual minority stress and openness about sexual minority status (i.e., outness). DNA methylation-derived outcomes included the following: the extrinsic epigenetic age acceleration clock, telomere length, naive CD4+ T-helper cells, and naive CD8+ T-cytotoxic/suppressor cells.

RESULTS

After adjusting for negative affect and recent stimulant use, higher sexual minority stress was associated with a faster extrinsic epigenetic age acceleration clock ( β = 0.29, p = .030), shorter telomere length ( β = -0.43, p = .002), and fewer naive CD4+ (β = -0.57, p < .001) and naive CD8+ T cells ( β = -0.57, p < .001). Greater outness was associated with higher naive CD4+ ( β = 0.32, p = .030) and naive CD8+ T cells ( β = 0.38, p = .008) as well as lower plasma interleukin 6 ( β = -0.33, p = .027).

CONCLUSIONS

Sexual minority stress processes are associated with markers of cellular aging and inflammation in methamphetamine-using sexual minority men living with HIV. Longitudinal research should elucidate biobehavioral mechanisms linking sexual minority stress processes with accelerated cellular aging in those with and without HIV.

Association of Plasma Eicosanoid Levels With Immune, Viral, and Cognitive Outcomes in People With HIV

BACKGROUND AND OBJECTIVES

To determine whether plasma eicosanoid levels are associated with immune, viral, and cognitive outcomes in people with HIV (PWH).

METHODS

We measured 42 eicosanoids in a longitudinal study of 95 PWH and 25 demographically comparable uninfected participants. Routine clinical chemistry, virologic, immune markers, and a neuropsychological test battery assessing 7 cognitive domains were administered to all participants at 2 study visits over an average of 6.5 months.

RESULTS

Plasma eicosanoid concentrations were elevated in PWH (n = 95) compared with seronegative controls (n = 25) (100% prediction power at 5% false discovery rate [FDR], α = 0.0531) and were negatively associated with lower current and nadir CD4 lymphocyte counts. Higher levels of eicosanoids were associated with impairments in working memory, verbal fluency, and executive function. Higher plasma viral load was associated with elevated proinflammatory eicosanoids (24% prediction power at 5% FDR and 42.4% prediction power at 10% FDR, α = 0.10). Longitudinal analyses showed that eicosanoid levels were correlated with viral load and with plasma creatinine. Despite associations of eicosanoids with viral loads, elevated plasma eicosanoids were similar in virally suppressed and not fully suppressed PWH.

DISCUSSION

These data show that HIV infection is associated with a robust production of eicosanoids that are not substantially reduced by antiretroviral therapy (ART). The sustained elevation of these oxylipins in PWH despite ART may contribute to an accelerated aging phenotype that includes earlier than expected brain and peripheral organ damage.

Characterization of Macrophage-Tropic HIV-1 Infection of Central Nervous System Cells and the Influence of Inflammation

HIV-1 infection within the central nervous system (CNS) includes evolution of the virus, damaging inflammatory cascades, and the involvement of multiple cell types; however, our understanding of how Env tropism and inflammation can influence CNS infectivity is incomplete. In this study, we utilize macrophage-tropic and T cell-tropic HIV-1 Env proteins to establish accurate infection profiles for multiple CNS cells under basal and interferon alpha (IFN-α) or lipopolysaccharide (LPS)-induced inflammatory states. We found that macrophage-tropic viruses confer entry advantages in primary myeloid cells, including monocyte-derived macrophage, microglia, and induced pluripotent stem cell (iPSC)-derived microglia. However, neither macrophage-tropic or T cell-tropic HIV-1 Env proteins could mediate infection of astrocytes or neurons, and infection was not potentiated by induction of an inflammatory state in these cells. Additionally, we found that IFN-α and LPS restricted replication in myeloid cells, and IFN-α treatment prior to infection with vesicular stomatitis virus G protein (VSV G) Envs resulted in a conserved antiviral response across all CNS cell types. Further, using RNA sequencing (RNA-seq), we found that only myeloid cells express HIV-1 entry receptor/coreceptor transcripts at a significant level and that these transcripts in select cell types responded only modestly to inflammatory signals. We profiled the transcriptional response of multiple CNS cells to inflammation and found 57 IFN-induced genes that were differentially expressed across all cell types. Taken together, these data focus attention on the cells in the CNS that are truly permissive to HIV-1, further highlight the role of HIV-1 Env evolution in mediating infection in the CNS, and point to limitations in using model cell types versus primary cells to explore features of virus-host interaction. IMPORTANCE The major feature of HIV-1 pathogenesis is the induction of an immunodeficient state in the face of an enhanced state of inflammation. However, for many of those infected, there can be an impact on the central nervous system (CNS) resulting in a wide range of neurocognitive defects. Here, we use a highly sensitive and quantitative assay for viral infectivity to explore primary and model cell types of the brain for their susceptibility to infection using viral entry proteins derived from the CNS. In addition, we examine the ability of an inflammatory state to alter infectivity of these cells. We find that myeloid cells are the only cell types in the CNS that can be infected and that induction of an inflammatory state negatively impacts viral infection across all cell types.

HIV-associated dementia presenting predominantly with clinical motor deficits: A case report

HIV-associated dementia is commonly seen in older individuals and presents as a subcortical dementia associated with concentration, attention, and memory impairments. Motor signs, such as difficulty with gait, and mood changes are less prominent findings but are considered during diagnosis. We present a case of HIV-associated dementia in a young 29-year-old man who presented with progressive lower extremity weakness and difficulty ambulating.

HIV and AIDS in Older Adults: Neuropsychiatric Changes

PURPOSE OF REVIEW

Patients diagnosed with HIV can now survive well into their old age. Aging with HIV is not only associated with comorbid medical illnesses but also with neuropsychiatric conditions that can range from cognitive changes to severe behavioral manifestations. This paper reviews mood, anxiety, and cognitive changes in older patients with HIV, as well as some of the treatment challenges in this population.

RECENT FINDINGS

Most recent findings show that untreated HIV illness over a long period of time may further worsen both preexisting neuropsychiatric illness and may cause new onset behavioral and cognitive symptoms. HIV induces immune phenotypic changes that have been compared to accelerated aging Low CD 4 counts and high viral counts are indicative of poor prognosis. Evaluation for potential HIV infections may be overlooked in older adults and require screening. Older adults experience accelerated CD4 cell loss. Older adults endorsing new onset mood or cognitive changes must be screened for HIV infection. New onset neurobehavioral symptoms should be carefully screened for and treated simultaneously in patients with HIV infection.

Recent Synergy of Nanodiamonds: Role in Brain-Targeted Drug Delivery for the Management of Neurological Disorders

The aim of the present review article is to summarize the role of nanodiamonds in various neurological diseases. We have taken related literature of making this review article from ScienceDirect, springer, Research gate, PubMed, Sci-finder, etc. The current approaches for treating neurological conditions such as glioblastoma includes chemotherapy or combination anti-retro viral therapy for HIV (human immunodeficiency virus) or use of anti-Alzheimer drugs during cognitive impairment. These approaches can provide only symptomatic relief as they do not target the cause of the disease due to their inability to penetrate the blood brain barrier. On long-term use, they may cause CNS toxicity due to accumulation in the brain. So nanodiamonds could prove as a promising approach in the brain targeting of the bioactive and to treat many neurological disorders such as Alzheimer's disease, Parkinson's disease, brain tumor (glioblastoma), HIV, amyotrophic multiple sclerosis, Huntington disease, stroke (cerebrovascular attack), batten disease, schizophrenia, epilepsy, and bacterial infections (encephalitis, sepsis, and meningitis) due to their ability to penetrate the blood-brain barrier and owing to their excellent surface properties, i.e., nano size and high surface area, ease of functionalization, multiple drug binding, and biocompatibility; they can be useful for brain targeted drug delivery with minimal side effects.

SUMOylation and Viral Infections of the Brain

The small ubiquitin-like modifier (SUMO) system regulates numerous biological processes, including protein localization, stability and/or activity, transcription, and DNA repair. SUMO also plays critical roles in innate immunity and antiviral defense by mediating interferon (IFN) synthesis and signaling, as well as the expression and function of IFN-stimulated gene products. Viruses including human immunodeficiency virus-1, Zika virus, herpesviruses, and coronaviruses have evolved to exploit the host SUMOylation system to counteract the antiviral activities of SUMO proteins and to modify their own proteins for viral persistence and pathogenesis. Understanding the exploitation of SUMO is necessary for the development of effective antiviral therapies. This review summarizes the interplay between viruses and the host SUMOylation system, with a special emphasis on viruses with neuro-invasive properties that have pathogenic consequences on the central nervous system.

The Role of Pannexin-1 Channels in HIV and NeuroHIV Pathogenesis

The human immunodeficiency virus-1 (HIV) enters the brain shortly after infection, leading to long-term neurological complications in half of the HIV-infected population, even in the current anti-retroviral therapy (ART) era. Despite decades of research, no biomarkers can objectively measure and, more importantly, predict the onset of HIV-associated neurocognitive disorders. Several biomarkers have been proposed; however, most of them only reflect late events of neuronal damage. Our laboratory recently identified that ATP and PGE2, inflammatory molecules released through Pannexin-1 channels, are elevated in the serum of HIV-infected individuals compared to uninfected individuals and other inflammatory diseases. More importantly, high circulating ATP levels, but not PGE2, can predict a decline in cognition, suggesting that HIV-infected individuals have impaired ATP metabolism and associated signaling. We identified that Pannexin-1 channel opening contributes to the high serological ATP levels, and ATP in the circulation could be used as a biomarker of HIV-associated cognitive impairment. In addition, we believe that ATP is a major contributor to chronic inflammation in the HIV-infected population, even in the anti-retroviral era. Here, we discuss the mechanisms associated with Pannexin-1 channel opening within the circulation, as well as within the resident viral reservoirs, ATP dysregulation, and cognitive disease observed in the HIV-infected population.

Application of Diffusion Tensor Imaging (DTI) in the Diagnosis of HIV-Associated Neurocognitive Disorder (HAND): A Meta-Analysis and a System Review

Background

The patients with HIV-associated neurocognitive disorder (HAND) are often accompanied by white matter structure damage. Diffusion tensor imaging (DTI) is an important tool to detect white matter structural damage. However, the changes in DTI values reported in many studies are diverse in different white matter fiber tracts and brain regions.

Purpose

Our research is dedicated to evaluating the consistency and difference of the correlation between HAND and DTI measures in different studies. Additionally, the value of DTI in HAND evaluation is used to obtain consensus and independent conclusions between studies.

Methods

We searched PubMed and Web of Science to collect relevant studies using DTI for the diagnosis of HAND. After screening and evaluating the search results, meta-analysis is used for quantitative research on data. Articles that cannot collect data but meet the research relevance will be subjected to a system review.

Results

The meta-analysis shows that the HAND group has lower fractional anisotropy (standardized mean difference = −0.57 p < 0.0001) and higher mean diffusivity (standardized mean difference = 0.04 p < 0.0001) than the healthy control group in corpus callosum. In other white matter fibers, we found similar changes in fractional anisotropy (standardized mean difference = −1.18 p < 0.0001) and mean diffusivity (standardized mean difference = 0.69 p < 0.0001). However, the heterogeneity (represented by I²) between the studies is high (in corpus callosum 94, 88%, in other matter fibers 95, 81%). After subgroup analysis, the heterogeneity is obtained as 19.5, 40.7% (FA, MD in corpus callosum) and 0, 0% (FA, MD among other white matter fibers).

Conclusion

The changes in white matter fibers in patients with HAND are statistically significant at the observation level of DTI compared with healthy people. The differences between the studies are mainly derived from demographics, start and maintenance time of antiretroviral therapy, differences in nadir CD4+T cells, and the use of different neurocognitive function scales. As an effective method to detect the changes in white matter fibers, DTI is of great significance for the diagnosis of HAND, but there are still some shortcomings. In the absence of neurocognitive function scales, independent diagnosis remains difficult.

Systematic Review Registration:https://inplasy.com/inplasy-2021-10-0079/.

Insights Into the Role of Mortalin in Alzheimer’s Disease, Parkinson’s Disease, and HIV-1-Associated Neurocognitive Disorders

Mortalin is a chaperone protein that regulates physiological functions of cells. Its multifactorial role allows cells to survive pathological conditions. Pharmacological, chemical, and siRNA-mediated downregulation of mortalin increases oxidative stress, mitochondrial dysfunction leading to unregulated inflammation. In addition to its well-characterized function in controlling oxidative stress, mitochondrial health, and maintaining physiological balance, recent evidence from human brain autopsies and cell culture–based studies suggests a critical role of mortalin in attenuating the damage seen in several neurodegenerative diseases. Overexpression of mortalin provides an important line of defense against accumulated proteins, inflammation, and neuronal loss, a key characteristic feature observed in neurodegeneration. Neurodegenerative diseases are a group of progressive disorders, sharing pathological features in Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, and HIV-associated neurocognitive disorder. Aggregation of insoluble amyloid beta-proteins and neurofibrillary tangles in Alzheimer’s disease are among the leading cause of neuropathology in the brain. Parkinson’s disease is characterized by the degeneration of dopamine neurons in substantia nigra pars compacta. A substantial synaptic loss leading to cognitive decline is the hallmark of HIV-associated neurocognitive disorder (HAND). Brain autopsies and cell culture studies showed reduced expression of mortalin in Alzheimer’s, Parkinson’s, and HAND cases and deciphered the important role of mortalin in brain cells. Here, we discuss mortalin and its regulation and describe how neurotoxic conditions alter the expression of mortalin and modulate its functions. In addition, we also review the neuroprotective role of mortalin under neuropathological conditions. This knowledge showcases the importance of mortalin in diverse brain functions and offers new opportunities for the development of therapeutic targets that can modulate the expression of mortalin using chemical compounds.

Recruitment of the CoREST transcription repressor complexes by Nerve Growth factor IB-like receptor (Nurr1/NR4A2) mediates silencing of HIV in microglial cells

Human immune deficiency virus (HIV) infection in the brain leads to chronic neuroinflammation due to the production of pro-inflammatory cytokines, which in turn promotes HIV transcription in infected microglial cells. However, powerful counteracting silencing mechanisms in microglial cells result in the rapid shutdown of HIV expression after viral reactivation to limit neuronal damage. Here we investigated whether the Nerve Growth Factor IB-like nuclear receptor Nurr1 (NR4A2), which is a repressor of inflammation in the brain, acts directly to restrict HIV expression. HIV silencing following activation by TNF-α, or a variety of toll-like receptor (TLR) agonists, in both immortalized human microglial cells (hμglia) and induced pluripotent stem cells (iPSC)-derived human microglial cells (iMG) was enhanced by Nurr1 agonists. Similarly, overexpression of Nurr1 led to viral suppression, while conversely, knock down (KD) of endogenous Nurr1 blocked HIV silencing. The effect of Nurr1 on HIV silencing is direct: Nurr1 binds directly to the specific consensus binding sites in the U3 region of the HIV LTR and mutation of the Nurr1 DNA binding domain blocked its ability to suppress HIV-1 transcription. Chromatin immunoprecipitation (ChIP) assays also showed that after Nurr1 binding to the LTR, the CoREST/HDAC1/G9a/EZH2 transcription repressor complex is recruited to the HIV provirus. Finally, transcriptomic studies demonstrated that in addition to repressing HIV transcription, Nurr1 also downregulated numerous cellular genes involved in inflammation, cell cycle, and metabolism, further promoting HIV latency and microglial homoeostasis. Nurr1 therefore plays a pivotal role in modulating the cycles of proviral reactivation by potentiating the subsequent proviral transcriptional shutdown. These data highlight the therapeutic potential of Nurr1 agonists for inducing HIV silencing and microglial homeostasis and ultimately for the amelioration of the neuroinflammation associated with HIV-associated neurocognitive disorders (HAND).

Screening Accuracy of Mini Addenbrooke's Cognitive Examination Test for HIV-Associated Neurocognitive Disorders in People Ageing with HIV

Aging and increased cardiovascular risk are major drivers for HIV-associated neurocognitive disorders (HAND), for which accurate screenings are lacking. Mini-Addenbrooke's Cognitive Examination (MACE) reliably detects vascular and neurodegenerative cognitive decline among HIV-negative patients. We evaluated MACE diagnostic accuracy in detecting HAND in people living with HIV (PLWH) and we compared it with the International HIV Dementia Scale (IHDS). A single-centre double-blind study of diagnostic accuracy on adult outpatient PLWH without neurocognitive confounding was performed. MACE and IHDS were administered in 5 and 10 min by clinicians, followed by the reference standard battery (14 tests) by neuropsychologists. HAND diagnosis was based on the modified version of Frascati's criteria by Gisslén to reduce false positives. Exploratory cut-offs were evaluated for MACE. Diagnostic accuracy and clinical utility parameters were assessed. 231 patients were enrolled. 75.7% men with a median age, education, and length of infection of 54 (48-59), 10 (8-13) and 16 (5-25) years. HAND prevalence was 48.5% (38.9% asymptomatic impairment). Compared to IHDS, MACE sensitivity (89.3% vs 70.5%), specificity (94.1% vs 63.0%), correct classification rate (86.5% vs 66.7%), J index (0.83 vs 0.34), AUROC (0.97 vs 0.79), agreement with the gold standard (k 0.84 vs 0.33) and effect size in distinguishing HAND vs non-HAND (d 2.11 vs 1.15) were higher. Among PLWH aged 65 years and above (n = 37) MACE performance was consistently better than IHDS. The quick and easy-to-perform MACE could possess an accurate and useful screening performance for HAND in otherwise neurocognitively healthy cohorts of PLWH.

Association of High Ratio of CSF/Plasma HIV-1 RNA with Central Nervous System Co-Infection in HIV-1-Positive Treatment-Naive Patients

Cerebrospinal fluid (CSF) human immunodeficiency virus-1 (HIV-1) ribonucleic acid (RNA) at higher levels than in plasma has been observed in HIV-1-positive patients and defined as CSF/plasma discordance or CSF escape. Discordance is particularly seen in untreated patients with antiretroviral agents. Quantitative data regarding its association with blood−brain barrier (BBB) damage and intracranial co-infection with other pathogens are limited. Therefore, we used the CSF to plasma HIV-1 RNA ratio (HRR) to determine its relation to central nervous system (CNS) co-infection in HIV-1-positive treatment-naïve individuals. We retrospectively recruited the subjects with HIV-1-positive and potential neurological deficits. A lumbar puncture was performed before the antiretroviral therapy. The paired CSF/plasma HIV-1 RNA samples were analyzed. Univariate and multivariate logistic regression models and multiple spine regression analyses were performed to assess the association between the HRR and CNS co-infection. A total of 195 patients with 78% males (median age: 49 years) were included in this study, of whom 98 (50.2%) had CNS co-infection with other pathogens. The receiver-operating characteristic curve analysis showed that the optimal cutoff value for the HRR to predict the CNS co-infection was 1.00. Higher HRR (≥1) was significantly associated with tuberculous meningitis (OR 6.50, 95% CI 2.08−20.25, p = 0.001), cryptococcus meningitis (OR 7.58, 95% CI 2.10−27.32, p = 0.001), and multiple co-infection (OR 4.04, 95% CI 1.02−16.04, p = 0.047). Higher HRR (≥1) (OR 3.01, 95% CI 1.09−8.73, p = 0.032) was independently associated with the CNS co-infection after adjusting for covariates. No significant nonlinear association was found between the HRR and CNS co-infection in the multivariate spline regression (p > 0.05) and a positive relationship was found between the HRR and CNS co-infection when the HRR was ≥0.78. Higher HRR was associated with an increased risk of CNS co-infection in HIV-1-positive patients. The relationship between the HRR and CNS co-infection may be related to the BBB disturbance and warrants further investigation with a large, longitudinal cohort.

Using plasma proteomics to investigate viral infections of the central nervous system including patients with HIV-associated neurocognitive disorders

State-of-the-art liquid chromatography/mass spectrometry (LC/MS)-based proteomic technologies, using microliter amounts of patient plasma, can detect and quantify several hundred plasma proteins in a high throughput fashion, allowing for the discovery of clinically relevant protein biomarkers and insights into the underlying pathobiological processes. Using such an in-house developed high throughput plasma proteomics allowed us to identify and quantify > 400 plasmas proteins in 15 min per sample, i.e., a throughput of 100 samples/day. We demonstrated the clinical applicability of our method in this pilot study by mapping the plasma proteomes from patients infected with human immunodeficiency virus (HIV) or herpes virus, both groups with involvement of the central nervous system (CNS). We found significant disease-specific differences in the plasma proteomes. The most notable difference was a decrease in the levels of several coagulation-associated proteins in HIV vs. herpes virus, among other dysregulated biological pathways providing insight into the differential pathophysiology of HIV compared to herpes virus infection. In a subsequent analysis, we found several plasma proteins associated with immunity and metabolism to differentiate patients with HIV-associated neurocognitive disorders (HAND) compared to cognitively normal people with HIV (PWH), suggesting the presence of plasma-based biomarkers to distinguishing HAND from cognitively normal PWH. Overall, our high-throughput plasma proteomics pipeline enables the identification of distinct proteomic signatures of HIV and herpes virus, which may help illuminate divergent pathophysiology behind virus-associated neurological disorders.

Higher buccal mitochondrial DNA and mitochondrial common deletion number are associated with markers of neurodegeneration and inflammation in cerebrospinal fluid

Human immunodeficiency virus (HIV) infection is potentially associated with premature aging, but demonstrating this is difficult due to a lack of reliable biomarkers. The mitochondrial (mt) DNA "common deletion" mutation (mtCDM) is a 4977-bp deletion associated with aging and neurodegenerative diseases. We examined how mtDNA and mtCDM correlate with markers of neurodegeneration and inflammation in people with and without HIV (PWH and PWOH). Data from 149 adults were combined from two projects involving PWH (n = 124) and PWOH (n = 25). We measured buccal mtDNA and mtCDM by digital droplet PCR and compared them to disease and demographic characteristics and soluble biomarkers in cerebrospinal fluid (CSF) and blood measured by immunoassay. Participants had a median age of 52 years, with 53% white and 81% men. Median mtDNA level was 1,332 copies/cell (IQR 1,201-1,493) and median mtCDM level was 0.36 copies × 102/cell (IQR 0.31-0.42); both were higher in PWH. In the best model adjusting for HIV status and demographics, higher mtDNA levels were associated with higher CSF amyloid-β 1-42 and 8-hydroxy-2'-deoxyguanosine and higher mtCDM levels were associated with higher plasma soluble tumor necrosis factor receptor II. The differences in mtDNA markers between PWH and PWOH support potential premature aging in PWH. Our findings suggest mtDNA changes in oral tissues may reflect CNS processes, allowing the use of inexpensive and easily accessible buccal biospecimens as a screening tool for CSF inflammation and neurodegeneration. Confirmatory and mechanistic studies on mt genome alterations by HIV and ART may identify interventions to prevent or treat neurodegenerative complications.

MicroPET evidence for a hypersensitive neuroinflammatory profile of gp120 mouse model of HIV

Despite increased survivability for people living with HIV (PLWH), HIV-related cognitive deficits persist. Determining biological mechanism(s) underlying abnormalities is critical to minimize the long-term impact of HIV. Positron emission tomography (PET) studies reveal that PLWH exhibit elevated neuroinflammation, potentially contributing to these problems. PLWH are hypersensitive to environmental insults that drive elevated inflammatory profiles. Gp120 is an envelope glycoprotein exposed on the surface of the HIV envelope which enables HIV entry into a cell contributing to HIV-related neurotoxicity. In vivo evidence for mice overexpressing gp120 (transgenic) mice exhibiting neuroinflammation remains unclear. Here, we conducted microPET imaging in gp120 transgenic and wildtype mice, using the radiotracer [(18)F]FEPPA (binds to the translocator protein expressed by activated microglial serving as a neuroinflammatory marker). Imaging was performed at baseline and 24 h after lipopolysaccharide (LPS; 5 mg/kg) treatment (endotoxin that triggers an immune response). Gp120 transgenic mice exhibited elevated [(18F)]FEPPA in response to LPS vs. wildtype mice throughout the brain including dorsal and ventral striata, hypothalamus, and hippocampus. Gp120 transgenic mice are hypersensitive to environmental inflammatory insults, consistent with PLWH, measurable in vivo. It remains to-be-determined whether this heightened sensitivity is connected to the behavioral abnormalities of these mice or sensitive to any treatments.

Neurological soft signs and brain morphology in people living with HIV

Neurological soft signs (NSS) are a common feature of severe psychiatric disorders such as schizophrenia but are also prevalent in organic brain diseases like HIV-associated neurocognitive disorder (HAND) or Alzheimer’s disease. While distinct associations between NSS, neurocognition, and cerebral regions were demonstrated in schizophrenia, these associations still have to be elucidated in HIV. Therefore, we investigated 36 persons with HIV of whom 16 were neurocognitively healthy and 20 were diagnosed with HAND. NSS were assessed using the Heidelberg scale. NSS scores were correlated with gray matter (GM) using whole brain voxel-based morphometry. Results showed significantly elevated NSS in the HAND group when compared to the neurocognitively healthy with respect to NSS total score and the subscores “orientation” and “complex motor tasks”. While the two groups showed only minor, non-significant GM differences, higher NSS scores (subscales “motor coordination”, “orientation”) were significantly correlated with GM reduction in the right insula and cerebellum (FWE-corrected). Our results corroborate elevated NSS in HIV+ patients with HAND in contrast to cognitively unimpaired patients. In addition, cerebral correlates of NSS with GM reductions in insula and cerebellum were revealed. Taken together, NSS in this patient group could be considered a marker of cerebral damage and neurocognitive deficits.

Neurofunctional characteristics of executive control in older people with HIV infection: a comparison with Parkinson's disease

Expression of executive dysfunctions is marked by substantial heterogeneity in people living with HIV infection (PLWH) and attributed to neuropathological degradation of frontostriatal circuitry with age and disease. We compared the neurophysiology of executive function in older PLWH and Parkinson's disease (PD), both affecting frontostriatal systems. Thirty-one older PLWH, 35 individuals with PD, and 28 older healthy controls underwent executive task-activated fMRI, neuropsychological testing, and a clinical motor exam. fMRI task conditions distinguished cognitive control operations, invoking a lateral frontoparietal network, and motor control operations, activating a cerebellar-precentral-medial prefrontal network. HIV-specific findings denoted a prominent sensorimotor hypoactivation during cognitive control and striatal hypoactivation during motor control related to CD4⁺ T cell count and HIV disease duration. Activation deficits overlapped for PLWH and PD, relative to controls, in dorsolateral frontal, medial frontal, and middle cingulate cortices for cognitive control, and in limbic, frontal, parietal, and cerebellar regions for motor control. Thus, despite well-controlled HIV infection, frontostriatal and sensorimotor activation deficits occurred during executive control in older PLWH. Overlapping activation deficits in posterior cingulate and hippocampal regions point toward similarities in mesocorticolimbic system aberrations among older PLWH and PD. The extent of pathophysiology in PLWH was associated with variations in immune system health, neural signature consistent with subclinical parkinsonism, and mild neurocognitive impairment. The failure to adequately engage these pathways could be an early sign for cognitive and motor functional decline in the aging population of PLWH.

Inhibitory Neurotransmission Is Sex-Dependently Affected by Tat Expression in Transgenic Mice and Suppressed by the Fatty Acid Amide Hydrolase Enzyme Inhibitor PF3845 via Cannabinoid Type-1 Receptor Mechanisms

(1) Background. The endocannabinoid (eCB) system, which regulates physiological and cognitive processes, presents a promising therapeutic target for treating HIV-associated neurocognitive disorders (HAND). Here we examine whether upregulating eCB tone has potential protective effects against HIV-1 Tat (a key HIV transactivator of transcription) protein-induced alterations in synaptic activity. (2) Methods. Whole-cell patch-clamp recordings were performed to assess inhibitory GABAergic neurotransmission in prefrontal cortex slices of Tat transgenic male and female mice, in the presence and absence of the fatty acid amide hydrolase (FAAH) enzyme inhibitor PF3845. Western blot and mass spectrometry analyses assessed alterations of cannabinoid receptor and enzyme protein expression as well as endogenous ligands, respectively, to determine the impact of Tat exposure on the eCB system. (3) Results. GABAergic activity was significantly altered upon Tat exposure based on sex, whereas the effectiveness of PF3845 to suppress GABAergic activity in Tat transgenic mice was not altered by Tat or sex and involved CB1R-related mechanisms that depended on calcium signaling. Additionally, our data indicated sex-dependent changes for AEA and related non-eCB lipids based on Tat induction. (4) Conclusion. Results highlight sex- and/or Tat-dependent alterations of GABAergic activity and eCB signaling in the prefrontal cortex of Tat transgenic mice and further increase our understanding about the role of FAAH inhibition in neuroHIV.

Comparison of dementia incidence and prevalence between individuals with and without HIV infection in primary care from 2000 to 2016

OBJECTIVE

To compare dementia incidence and prevalence after age 50 years by HIV status.

DESIGN

Observational cohort, 2000-2016.

METHODS

People with HIV (PWH) on antiretroviral therapy (ART) and demographically similar people without HIV (PWoH), all aged 50 years and older, were identified from Kaiser Permanente healthcare systems in Northern California, Southern California, and Mid-Atlantic States (Maryland, Virginia, Washington DC). Dementia diagnoses were obtained from electronic health records. Incidence and prevalence of dementia, overall and by time period (i.e. 2000-2002, 2003-2004, …, 2015-2016), were calculated using Poisson regression. Trends were examined using Joinpoint regression. Rate ratios were used to compare dementia by HIV status with adjustment for sociodemographics, substance use, and clinical factors.

RESULTS

The study included 13 296 PWH and 155 354 PWoH (at baseline: for both, mean age = 54 years, 89% men; for PWH, 80% with HIV RNA <200 copies/ml). From 2000 to 2016, overall incidence of dementia was higher among PWH [adjusted incidence rate ratio (aIRR) = 1.80, 95% confidence interval (CI) = 1.60-2.04]. Dementia incidence decreased among both PWH and PWoH (-8.0 and -3.1% per period, respectively) but remained higher among PWH in the most recent time period, 2015-2016 (aIRR = 1.58, 95% CI = 1.18-2.12). The overall prevalence of dementia from 2000 to 2016 was higher among PWH [adjusted prevalence ratio (aPR) = 1.86, 95% CI = 1.70-2.04] and was also higher among PWH in 2015-2016 (aPR = 1.75, 95% CI = 1.56-1.97).

CONCLUSION

Reductions in dementia incidence are encouraging and may reflect ART improvement, but PWH are still more likely to have dementia than PWoH. Monitoring the burden of dementia among PWH is important as this population ages.

Cannabinoids Reduce Extracellular Vesicle Release from HIV-1 Infected Myeloid Cells and Inhibit Viral Transcription

Of the 37.9 million individuals infected with human immunodeficiency virus type 1 (HIV-1), approximately 50% exhibit HIV-associated neurocognitive disorders (HAND). We and others previously showed that HIV-1 viral RNAs, such as trans-activating response (TAR) RNA, are incorporated into extracellular vesicles (EVs) and elicit an inflammatory response in recipient naïve cells. Cannabidiol (CBD) and Δ9-tetrahydrocannabinol (THC), the primary cannabinoids present in cannabis, are effective in reducing inflammation. Studies show that cannabis use in people living with HIV-1 is associated with lower viral load, lower circulating CD16+ monocytes and high CD4+ T-cell counts, suggesting a potentially therapeutic application. Here, HIV-1 infected U1 monocytes and primary macrophages were used to assess the effects of CBD. Post-CBD treatment, EV concentrations were analyzed using nanoparticle tracking analysis. Changes in intracellular and EV-associated viral RNA were quantified using RT-qPCR, and changes in viral proteins, EV markers, and autophagy proteins were assessed by Western blot. Our data suggest that CBD significantly reduces the number of EVs released from infected cells and that this may be mediated by reducing viral transcription and autophagy activation. Therefore, CBD may exert a protective effect by alleviating the pathogenic effects of EVs in HIV-1 and CNS-related infections.

Neurological disorders in HIV: Hope despite challenges

Introduction

Human Immunodeficiency virus (HIV) is a virus that causes several diseases by attacking the human immune system. It is transmitted by contact with certain bodily fluids of an infected person, most commonly during unprotected sex, through sharing needles, or from mother to baby during pregnancy, birth or breastfeeding. The central nervous system is not spared from this virus, as HIV has been shown to induce several neurological disorders. However most neurological pathologies (such as dementia, infections, meningitis, and neuropathy) rarely show until late stages, in this case, after the patients develop acquired immunodeficiency syndrome (AIDS). This article aims to review the neurological disorders in the HIV population and the attempts initiated to limit the disease.

Methodology

Data were collected from medical journals published on PubMed, Ovid MEDLINE, Science Direct and Embase bibliographical databases with a predefined search strategy. All articles considering neurological disorders associated with HIV were considered.

Results

To date, the pathogenesis of HIV‐associated neurological complications remains poorly elucidated; thus, imposing a hindrance and limitations on the treatment options. Nevertheless, some studies have reported alterations in dendritic spine as the causative agent for developing brain damage.

Conclusion

HIV remains one of the most serious global health challenges, with neurological manifestations imposing a major concern among patients with HIV. Despite the availability and efficacy of antiretroviral therapies, yet, the risk of developing neurological complications remains relatively high among patients with HIV. Thus, the 2030 HIV vision must focus on further preventive measures to protect HIV patients from developing such neurological complications.

Retroviral infection of human neurospheres and use of stem Cell EVs to repair cellular damage

HIV-1 remains an incurable infection that is associated with substantial economic and epidemiologic impacts. HIV-associated neurocognitive disorders (HAND) are commonly linked with HIV-1 infection; despite the development of combination antiretroviral therapy (cART), HAND is still reported to affect at least 50% of HIV-1 infected individuals. It is believed that the over-amplification of inflammatory pathways, along with release of toxic viral proteins from infected cells, are primarily responsible for the neurological damage that is observed in HAND; however, the underlying mechanisms are not well-defined. Therefore, there is an unmet need to develop more physiologically relevant and reliable platforms for studying these pathologies. In recent years, neurospheres derived from induced pluripotent stem cells (iPSCs) have been utilized to model the effects of different neurotropic viruses. Here, we report the generation of neurospheres from iPSC-derived neural progenitor cells (NPCs) and we show that these cultures are permissive to retroviral (e.g. HIV-1, HTLV-1) replication. In addition, we also examine the potential effects of stem cell derived extracellular vesicles (EVs) on HIV-1 damaged cells as there is abundant literature supporting the reparative and regenerative properties of stem cell EVs in the context of various CNS pathologies. Consistent with the literature, our data suggests that stem cell EVs may modulate neuroprotective and anti-inflammatory properties in damaged cells. Collectively, this study demonstrates the feasibility of NPC-derived neurospheres for modeling HIV-1 infection and, subsequently, highlights the potential of stem cell EVs for rescuing cellular damage induced by HIV-1 infection.

Human Brain Organoids as an In Vitro Model System of Viral Infectious Diseases

Brain organoids, or brainoids, have shown great promise in the study of central nervous system (CNS) infection. Modeling Zika virus (ZIKV) infection in brain organoids may help elucidate the relationship between ZIKV infection and microcephaly. Brain organoids have been used to study the pathogenesis of SARS-CoV-2, human immunodeficiency virus (HIV), HSV-1, and other viral infections of the CNS. In this review, we summarize the advances in the development of viral infection models in brain organoids and their potential application for exploring mechanisms of viral infections of the CNS and in new drug development. The existing limitations are further discussed and the prospects for the development and application of brain organs are prospected.

HIV Disease Dynamics and Markers of Inflammation and CNS Injury During Primary HIV Infection and Their Relationship to Cognitive Performance

INTRODUCTION

Early systemic and central nervous system viral replication and inflammation may affect brain integrity in people with HIV, leading to chronic cognitive symptoms not fully reversed by antiretroviral therapy (ART). This study examined associations between cognitive performance and markers of CNS injury associated with acute HIV infection and ART.

METHODS

HIV-infected MSM and transgender women (average age: 27 years and education: 13 years) enrolled within 100 days from the estimated date of detectable infection (EDDI). A cognitive performance (NP) protocol was administered at enrollment (before ART initiation) and every 24 weeks until week 192. An overall index of cognitive performance (NPZ) was created using local normative data. Blood (n = 87) and cerebrospinal fluid (CSF; n = 29) biomarkers of inflammation and neuronal injury were examined before ART initiation. Regression analyses assessed relationships between time since EDDI, pre-ART biomarkers, and NPZ.

RESULTS

Adjusting for multiple comparisons, shorter time since EDDI was associated with higher pre-ART VL and multiple biomarkers in plasma and CSF. NPZ scores were within the normative range at baseline (NPZ = 0.52) and at each follow-up visit, with a modest increase through week 192. Plasma or CSF biomarkers were not correlated with NP scores at baseline or after ART.

CONCLUSIONS

Biomarkers of CNS inflammation, immune activation, and neuronal injury peak early and then decline during acute HIV infection, confirming and extending results of other studies. Neither plasma nor CSF biomarkers during acute infection corresponded to NP scores before or after sustained ART in this cohort with few psychosocial risk factors for cognitive impairment.

Nutraceuticals in HIV and COVID-19-Related Neurological Complications: Opportunity to Use Extracellular Vesicles as Drug Delivery Modality

Simple Summary

In this review, we discuss the potential use of extracellular vesicles (EVs) to deliver dietary supplements to the brain to reduce brain complications associated with HIV, COVID-19, and other brain disorders. Brain-related complications affect people with HIV and COVID-19 alike. Moreover, since HIV patients are at a higher risk of contracting COVID-19, their neurological problems can be exacerbated by COVID-19. The use of dietary supplements together with available treatment options has been shown to reduce the severity of infections. However, these treatments are not chemically compatible with the body’s blood–brain barrier defense mechanism. Therefore, a viable delivery method is needed to deliver drugs and nutraceuticals to the brain in HIV and COVID-19 comorbid patients.

Abstract

People living with HIV/AIDS (PLWHA) are at an increased risk of severe and critical COVID-19 infection. There is a steady increase in neurological complications associated with COVID-19 infection, exacerbating HIV-associated neurocognitive disorders (HAND) in PLWHA. Nutraceuticals, such as phytochemicals from medicinal plants and dietary supplements, have been used as adjunct therapies for many disease conditions, including viral infections. Appropriate use of these adjunct therapies with antiviral proprieties may be beneficial in treating and/or prophylaxis of neurological complications associated with these co-infections. However, most of these nutraceuticals have poor bioavailability and cannot cross the blood–brain barrier (BBB). To overcome this challenge, extracellular vesicles (EVs), biological nanovesicles, can be used. Due to their intrinsic features of biocompatibility, stability, and their ability to cross BBB, as well as inherent homing capabilities, EVs hold immense promise for therapeutic drug delivery to the brain. Therefore, in this review, we summarize the potential role of different nutraceuticals in reducing HIV- and COVID-19-associated neurological complications and the use of EVs as nutraceutical/drug delivery vehicles to treat HIV, COVID-19, and other brain disorders.

Inhibition of Cathepsin B and SAPC Secreted by HIV-Infected Macrophages Reverses Common and Unique Apoptosis Pathways

Human immunodeficiency virus 1 (HIV-1) infects blood monocytes that cross the blood-brain barrier to the central nervous system, inducing neuronal damage. This is prompted by the secretion of viral and neurotoxic factors by HIV-infected macrophages, resulting in HIV-associated neurocognitive disorders. One of these neurotoxic factors is cathepsin B (CATB), a lysosomal cysteine protease that plays an important role in neurodegeneration. CATB interacts with the serum amyloid P component (SAPC), contributing to HIV-induced neurotoxicity. However, the neuronal apoptosis pathways triggered by CATB and the SAPC remain unknown. We aimed to elucidate these pathways in neurons exposed to HIV-infected macrophage-conditioned media before and after the inhibition of CATB or the SAPC with antibodies using tandem mass tag proteomics labeling. Based on the significant fold change (FC) ≥ |2| and p-value < 0.05 criteria, a total of 10, 48, and 13 proteins were deregulated after inhibiting CATB, SAPC antibodies, and the CATB inhibitor CA-074, respectively. We found that neurons exposed to the CATB antibody and SAPC antibody modulate similar proteins (TUBA1A and CYPA/PPIA) and unique proteins (LMNA and HSPH1 for the CATB antibody) or (CFL1 and PFN1 for the SAPC antibody). CATB, SAPC, or apoptosis-related proteins could become potential targets against HIV-induced neuronal degeneration.

The Importance of Tissue Sanctuaries and Cellular Reservoirs of HIV-1

Purpose of Review - There have been significant developments in the treatment of people living with HIV-1/AIDS with current antiretroviral therapies; however, these developments have not been able to achieve a functional or sterilizing cure for HIV-1. While there are multiple barriers, one such barrier is the existence of pharmacological sanctuaries and viral reservoirs where the concentration of antiretrovirals is suboptimal, which includes the gut-associated lymphoid tissue, central nervous system, lymph nodes, and myeloid cells. This review will focus on illustrating the significance of these sanctuaries, specific barriers to optimal antiretroviral concentrations in each of these sites, and potential strategies to overcome these barriers. Recent Findings - Research and studies have shown that a uniform antiretroviral distribution is not achieved with current therapies. This may allow for low-level replication associated with low antiretroviral concentrations in these sanctuaries/reservoirs. Many methods are being investigated to increase antiretroviral concentrations in these sites, such as blocking transporting enzymes functions, modulating transporter expression and nanoformulations of current antiretrovirals. While these methods have been shown to increase antiretroviral concentrations in the sanctuaries/reservoirs, no functional or sterilizing cure has been achieved due to these approaches. Summary - New methods of increasing antiretroviral concentrations at the specific sites of HIV-1 replication has the potential to target cellular reservoirs. In order to optimize antiretroviral distribution into viral sanctuaries/reservoirs, additional research is needed.

Why the HIV Reservoir Never Runs Dry: Clonal Expansion and the Characteristics of HIV-Infected Cells Challenge Strategies to Cure and Control HIV Infection

Antiretroviral therapy (ART) effectively reduces cycles of viral replication but does not target proviral populations in cells that persist for prolonged periods and that can undergo clonal expansion. Consequently, chronic human immunodeficiency virus (HIV) infection is sustained during ART by a reservoir of long-lived latently infected cells and their progeny. This proviral landscape undergoes change over time on ART. One of the forces driving change in the landscape is the clonal expansion of infected CD4 T cells, which presents a key obstacle to HIV eradication. Potential mechanisms of clonal expansion include general immune activation, antigenic stimulation, homeostatic proliferation, and provirus-driven clonal expansion, each of which likely contributes in varying, and largely unmeasured, amounts to maintaining the reservoir. The role of clinical events, such as infections or neoplasms, in driving these mechanisms remains uncertain, but characterizing these forces may shed light on approaches to effectively eradicate HIV. A limited number of individuals have been cured of HIV infection in the setting of bone marrow transplant; information from these and other studies may identify the means to eradicate or control the virus without ART. In this review, we describe the mechanisms of HIV-1 persistence and clonal expansion, along with the attempts to modify these factors as part of reservoir reduction and cure strategies.

Crucial Role of Central Nervous System as a Viral Anatomical Compartment for HIV-1 Infection

The chronic infection established by the human immunodeficiency virus 1 (HIV-1) produces serious CD4+ T cell immunodeficiency despite the decrease in HIV-1 ribonucleic acid (RNA) levels and the raised life expectancy of people living with HIV-1 (PLWH) through treatment with combined antiretroviral therapies (cART). HIV-1 enters the central nervous system (CNS), where perivascular macrophages and microglia are infected. Serious neurodegenerative symptoms related to HIV-associated neurocognitive disorders (HAND) are produced by infection of the CNS. Despite advances in the treatment of this infection, HAND significantly contribute to morbidity and mortality globally. The pathogenesis and the role of inflammation in HAND are still incompletely understood. Principally, growing evidence shows that the CNS is an anatomical reservoir for viral infection and replication, and that its compartmentalization can trigger the evolution of neurological damage and thus make virus eradication more difficult. In this review, important concepts for understanding HAND and neuropathogenesis as well as the viral proteins involved in the CNS as an anatomical reservoir for HIV infection are discussed. In addition, an overview of the recent advancements towards therapeutic strategies for the treatment of HAND is presented. Further neurological research is needed to address neurodegenerative difficulties in people living with HIV, specifically regarding CNS viral reservoirs and their effects on eradication.

Cognitive impairment in the HTLV-1 infection: a comparative study associated with functional performance

Human T cell leukemia virus type-I (HTLV-1) infection courses with a myelopathy, the tropical spastic paraparesis (HAM/TSP). In a case-control study, we compared the neuropsychological profile and functional characteristics in two case HTLV-1-infected groups (asymptomatic and with HAM/TSP) with a control group negative for HTLV-1. Subjects were paired for age, sex, and educational features. The case group differed from control group in neuropsychological measures such as in episodic memory recall, executive functions, and fine motor dexterity measure. Individuals with HAM/TSP have more depressive symptoms and worst performance in activities of daily living (ADL) presenting a less functionality. In multivariate models, the fine motor performance, the executive functioning, the recognition memory, and the depressive symptoms explained part of the variance in functionality. Those findings may contribute to understand of everyday life impairments and limitations of HTLV-1-infected population and to organize the rehabilitation. Once more, based in neuropsychological and functional data, we can reaffirm that HTLV-1 is never a benign condition, but sometimes it is only in a stage coursing with less symptoms.

Important role of microglia in HIV-1 associated neurocognitive disorders and the molecular pathways implicated in its pathogenesis

The development of effective combined anti-retroviral therapy (cART) led to a significant reduction in the death rate associated with human immunodeficiency virus type 1 (HIV-1) infection. However, recent studies indicate that considerably more than 50% of all HIV-1 infected patients develop HIV-1-associated neurocognitive disorder (HAND). Microglia are the foremost cells infected by HIV-1 in the central nervous system (CNS), and so, are also likely to contribute to the neurotoxicity observed in HAND. The activation of microglia induces the release of pro-inflammatory markers and altered secretion of cytokines, chemokines, secondary messengers, and reactive oxygen species (ROS) which activate signalling pathways that initiate neuroinflammation. In turn, ROS and inflammation also play critical roles in HAND. However, more efforts are required to understand the physiology of microglia and the processes involved in their activation in order to better understand the how HIV-1-infected microglia are involved in the development of HAND. In this review, we summarize the current state of knowledge about the involvement of oxidative stress mechanisms and role of HIV-induced ROS in the development of HAND. We also examine the academic literature regarding crucial HIV-1 pathogenicity factors implicated in neurotoxicity and inflammation in order to identify molecular pathways that could serve as potential therapeutic targets for treatment of this disease. KEY MESSAGES Neuroinflammation and excitotoxicity mechanisms are crucial in the pathogenesis of HAND. CNS infiltration by HIV-1 and immune cells through the blood brain barrier is a key process involved in the pathogenicity of HAND. Factors including calcium dysregulation and autophagy are the main challenges involved in HAND.

Abundance of Nef and p-Tau217 in Brains of Individuals Diagnosed with HIV-Associated Neurocognitive Disorders Correlate with Disease Severance

HIV-associated neurocognitive disorders (HAND) is a term used to describe a variety of neurological impairments observed in HIV-infected individuals. The pathogenic mechanisms of HAND and of its connection to HIV infection remain unknown, but one of the considered hypotheses suggests that HIV infection accelerates the development of Alzheimer’s disease. Previous studies suggested that HIV-1 Nef may contribute to HAND by inhibiting cholesterol efflux, increasing the abundance of lipid rafts, and affecting their functionality. Our comparative analysis of postmortem brain samples demonstrated a trend toward the decreased abundance of cholesterol transporter ABCA1 in samples from HIV-infected ART-treated individuals relative to samples from uninfected controls, and a reverse correlation between ABCA1 and flotillin 1, a marker for lipid rafts, in all analyzed samples. The brain samples from HIV-infected individuals, both with and without HAND, were characterized by the increased abundance of p-Tau217 peptide, which correlated with the abundance of flotillin 1. HIV-1 Nef was analyzed in samples from HAND-affected individuals by Western blot with 4 different antibodies and by LC–MS/MS, producing a Nef-positivity score. A significant correlation was found between this score and the abundance of flotillin 1, the abundance of p-Tau217, and the severity of HAND. These results highlight the contribution of Nef and Nef-dependent impairment of cholesterol efflux to HAND pathogenesis and support a connection between the pathogenesis of HAND and Alzheimer’s disease.

HIV-associated neurotoxicity and cognitive decline: Therapeutic implications

As our understanding of changes to the neurological system has improved, it has become clear that patients who have contracted human immunodeficiency virus type 1 (HIV-1) can potentially suffer from a cascade of neurological issues, including neuropathy, dementia, and declining cognitive function. The progression from mild to severe symptoms tends to affect motor function, followed by cognitive changes. Central nervous system deficits that are observed as the disease progresses have been reported as most severe in later-stage HIV infection. Examining the full spectrum of neuronal damage, generalized cortical atrophy is a common hallmark, resulting in the death of multiple classes of neurons. With antiretroviral therapy (ART), we can partially control disease progression, slowing the onset of the most severe symptoms such as, reducing viral load in the brain, and developing HIV-associated dementia (HAD). HAD is a severe and debilitating outcome from HIV-related neuropathologies. HIV neurotoxicity can be direct (action directly on the neuron) or indirect (actions off-site that affect normal neuronal function). There are two critical HIV-associated proteins, Tat and gp120, which bear responsibility for many of the neuropathologies associated with HAD and HIV-associated neurocognitive disorder (HAND). A cascade of systems is involved in HIV-related neurotoxicity, and determining a critical point where therapeutic strategies can be employed is of the utmost importance. This review will provide an overview of the existing hypotheses on HIV-neurotoxicity and the potential for the development of therapeutics to aid in the treatment of HIV-related nervous system dysfunction.

Whole-brain white matter network reorganization in HIV

The human immunodeficiency virus (HIV) causes an infectious disease with a high viral tropism toward CD4 T-lymphocytes and macrophage. Since the advent of combined antiretroviral therapy (CART), the number of opportunistic infectious disease has diminished, turning HIV into a chronic condition. Nevertheless, HIV-infected patients suffer from several life-long symptoms, including the HIV-associated neurocognitive disorder (HAND), whose biological substrates remain unclear. HAND includes a range of cognitive impairments which have a huge impact on daily patient life. The aim of this study was to examine putative structural brain network changes in HIV-infected patient to test whether diffusion-imaging-related biomarkers could be used to discover and characterize subtle neurological alterations in HIV infection. To this end, we employed multi-shell, multi-tissue constrained spherical deconvolution in conjunction with probabilistic tractography and graph-theoretical analyses. We found several statistically significant effects in both local (right postcentral gyrus, right precuneus, right inferior parietal lobule, right transverse temporal gyrus, right inferior temporal gyrus, right putamen and right pallidum) and global graph-theoretical measures (global clustering coefficient, global efficiency and transitivity). Our study highlights a global and local reorganization of the structural connectome which support the possible application of graph theory to detect subtle alteration of brain regions in HIV patients.Clinical Relevance-Brain measures able to detect subtle alteration in HIV patients could also be used in e.g. evaluating therapeutic responses, hence empowering clinical trials.

The HIV-1 matrix protein p17 does cross the Blood-Brain Barrier

Human immunodeficiency virus type-1(HIV-1)-associated neurocognitive disorder (HAND) remains an important neurological manifestation in HIV-1-infected (HIV⁺) patients. Furthermore, the HIV-1 matrix protein p17 (p17) detection in the central nervous system (CNS) and its ability to form toxic assemblies in the brain has been recently confirmed. Here we show for the first time using both an in vitro blood-brain barrier (BBB) model and in vivo biodistribution studies in healthy mice that p17 can cross the BBB. There is fast brain uptake with 0.35 ± 0.19% of injected activity per gram of tissue (I.A./g) two minutes after administration, followed by brain accumulation with 0.28 ± 0.09% I.A./g after 1 h. The interaction of p17 with the chemokine receptor 2 (CXCR2) at the surface of brain endothelial cells triggers transcytosis. The present study supports the hypothesis of a direct role of free p17 in neuronal dysfunction in HAND by demonstrating its intrinsic ability to reach the CNS. IMPORTANCE The number of patients affected by HIV-1-associated neurocognitive disorder (HAND) ranges from 30 to 50% of HIV-infected (HIV⁺) patients. The mechanisms leading to HAND development need to be elucidated, but the role of secreted viral proteins, chemokines, and proinflammatory molecules appears to be clear. In particular, the blood-brain barrier (BBB) represents a route for entry into the central nervous system (CNS) thus playing an important role in HAND. Several findings suggest a key role for the HIV-1 matrix protein p17 (p17) as a microenvironmental factor capable of inducing neurocognitive disorders. Here we show, the ability of the p17 to cross the BBB and to reach the CNS thus playing a crucial role in neuronal dysfunction in HAND.

Sirtuins as Interesting Players in the Course of HIV Infection and Comorbidities

The sirtuins (SIRTs) are a family of enzymes from the group of NAD⁺-dependent deacetylases. Through the reaction of splitting the acetyl group of various transcription factors and histones they regulate many processes in the organism. The activity of sirtuins is linked to metabolic control, oxidative stress, inflammation and apoptosis, and they also affect the course of viral infections. For this reason, they may participate in the pathogenesis and development of many diseases, but little is known about their role in the course of human immunodeficiency virus (HIV) infection, which is the subject of this review. In the course of HIV infection, comorbidities such as: neurodegenerative disorders, obesity, insulin resistance and diabetes, lipid disorders and cardiovascular diseases, renal and bone diseases developed more frequently and faster compared to the general population. The role of sirtuins in the development of accompanying diseases in the course of HIV infection may also be interesting. There is still a lack of detailed information on this subject. The role of sirtuins, especially SIRT1, SIRT3, SIRT6, are indicated to be of great importance in the course of HIV infection and the development of the abovementioned comorbidities.

MAT2A-Mediated S-Adenosylmethionine Level in CD4+ T Cells Regulates HIV-1 Latent Infection

Antiretroviral drugs effectively halt HIV-1 replication and disease progression, however, due to the presence of a stable viral latent reservoir, the infection cannot be cured by antiretroviral drugs alone. Elucidating the molecular mechanisms underlying HIV-1 latent infection remains a critical hurdle that precludes the development of novel therapeutic strategies aiming for a potential functional cure. Cellular metabolism has been reported to affect HIV-1 replication in CD4⁺ T cells, but it remains largely unclear whether it is involved in the regulation of HIV-1 latency. Here, we performed a sub-pooled CRISPR library knockout screen targeting 1773 metabolic-related genes in a cell model of HIV-1 latent infection and found that Methionine Adenosyltransferase 2A (MAT2A) contributes to HIV-1 latency. MAT2A knockout enhanced the reactivation of latent HIV-1 while MAT2A overexpression did the opposite. Mechanistically, MAT2A modulates HIV-1 latency through S-Adenosylmethionine (SAM)-mediated one-carbon flux. MAT2A knockout resulted in a significant downregulation of DNA and histone methylation at the HIV-1 5’-LTR. Importantly, we found that the plasma level of SAM is positively correlated with HIV-1 DNA in PBMCs from ART-treated infected individuals, suggesting SAM could serve as a potential biomarker for the latent viral reservoir. Overall, this study reveals an important role of MAT2A-mediated one-carbon metabolism in regulating HIV-1 latency and provides a promising target for the development of new strategies for a functional cure of HIV-1.

Components of metabolic syndrome associated with lower neurocognitive performance in youth with perinatally acquired HIV and youth who are HIV-exposed uninfected

We investigated the association of metabolic syndrome (MetS) and its components [abdominal obesity, elevated triglycerides (TG), low HDL cholesterol, elevated blood pressure (BP), and impaired fasting glycemia (IFG)] with neurocognitive impairment in youth with perinatally acquired HIV (YPHIV) or who are perinatally HIV-exposed uninfected (YPHEU). This was an observational study with a comparison group of 350 YPHIV and 68 YPHEU ages 10-19 years. Youth with MetS components measured between 1 year before and 3 months after a baseline neurocognitive assessment (Wechsler Intelligence Scale) were selected from the Pediatric HIV/AIDS Cohort Study (PHACS). A sub-group completed another assessment 3 years later. We assessed the association of each baseline MetS component with five standardized neurocognitive indices at baseline and changes in indices over time. At baseline, 15% of YPHIV and 18% of YPHEU met criteria for ≥ 2 MetS components. Among YPHIV, there was no association between MetS components and neurocognitive indices at baseline; however, over time, elevated baseline BP was associated with a greater decrease in mean Perceptual Reasoning scores (-4.3;95%CI: -8.8,0.3) and ≥ 2 MetS components with a greater decrease in mean Processing Speed scores (-5.1;95%CI: -9.4, -0.8). Among YPHEU, elevated TG was associated with lower mean Verbal Comprehension, Perceptual Reasoning, and Full-scale IQ scores at baseline, and IFG with lower mean Verbal Comprehension scores. Components of MetS in YPHIV (elevated BP) and YPHEU (elevated TG and IFG) were associated with lower neurocognitive performance index scores. Studies to elucidate how modifying metabolic risk factors early in life may improve neurocognitive outcomes in this population are warranted.

Co-receptor signaling in the pathogenesis of neuroHIV

The HIV co-receptors, CCR5 and CXCR4, are necessary for HIV entry into target cells, interacting with the HIV envelope protein, gp120, to initiate several signaling cascades thought to be important to the entry process. Co-receptor signaling may also promote the development of neuroHIV by contributing to both persistent neuroinflammation and indirect neurotoxicity. But despite the critical importance of CXCR4 and CCR5 signaling to HIV pathogenesis, there is only one therapeutic (the CCR5 inhibitor Maraviroc) that targets these receptors. Moreover, our understanding of co-receptor signaling in the specific context of neuroHIV is relatively poor. Research into co-receptor signaling has largely stalled in the past decade, possibly owing to the complexity of the signaling cascades and functions mediated by these receptors. Examining the many signaling pathways triggered by co-receptor activation has been challenging due to the lack of specific molecular tools targeting many of the proteins involved in these pathways and the wide array of model systems used across these experiments. Studies examining the impact of co-receptor signaling on HIV neuropathogenesis often show activation of multiple overlapping pathways by similar stimuli, leading to contradictory data on the effects of co-receptor activation. To address this, we will broadly review HIV infection and neuropathogenesis, examine different co-receptor mediated signaling pathways and functions, then discuss the HIV mediated signaling and the differences between activation induced by HIV and cognate ligands. We will assess the specific effects of co-receptor activation on neuropathogenesis, focusing on neuroinflammation. We will also explore how the use of substances of abuse, which are highly prevalent in people living with HIV, can exacerbate the neuropathogenic effects of co-receptor signaling. Finally, we will discuss the current state of therapeutics targeting co-receptors, highlighting challenges the field has faced and areas in which research into co-receptor signaling would yield the most therapeutic benefit in the context of HIV infection. This discussion will provide a comprehensive overview of what is known and what remains to be explored in regard to co-receptor signaling and HIV infection, and will emphasize the potential value of HIV co-receptors as a target for future therapeutic development.