HIV-1 infected monocyte-derived macrophages affect the human brain microvascular endothelial cell proteome: new insights into blood-brain barrier dysfunction for HIV-1-associated dementia

HIV-associated neurocognitive disorders (HAND): Optimal diagnosis, antiviral therapy, pharmacological treatment, management, and future scopes

In the context of HIV infection, HIV-associated neurocognitive disorders (HAND) have become a serious concern. An extensive summary of the diagnosis, care, and mental health consequences related to HAND is given in this article. The diagnosis of HAND entails a multimodal approach that includes neuroimaging, cognition tests, and clinical examinations. Numerous screening instruments and standardized evaluations have been created to support the early identification and tracking of HAND. Appropriate actions and individualized treatment plans are made possible by prompt diagnosis. A multidisciplinary approach is used in the treatment of HAND, aiming to address various elements of cognitive impairment. The main stream of treatment is still antiretroviral medication (ART), which successfully lowers viral loads and stops further neurocognitive deterioration. Adjunctive treatments are essential for treating cognitive symptoms and improving overall quality of life. These therapies include cognitive rehabilitation, pharmaceutical interventions, and psychological support. Our knowledge of the pathophysiology of HAND has improved with the identification of the inflammatory milieu and persistent viral persistence in the central nervous system (CNS), which has also aided in the creation of biomarkers for CNS illness. Although biomarkers show inflammation, neuronal damage, and monocyte activity, their clinical use is still restricted. Although new techniques to treating HAND have been developed as a result of a better knowledge of pathogenic processes, the best course of action is still unknown.

Structural and Functional Dysregulation of the Brain Endothelium in HIV Infection and Substance Abuse

Blood-brain barrier (BBB) injury and dysfunction following infection with the human immunodeficiency virus (HIV) enables viral entry into the brain, infection of resident brain cells, neuronal injury and subsequent neurodegeneration leading to HIV-associated neurocognitive disorders (HAND). Although combination antiretroviral therapy has significantly reduced the incidence and prevalence of acquired immunodeficiency syndrome and increased the life expectancy of people living with HIV, the prevalence of HAND remains high. With aging of people living with HIV associated with increased comorbidities, the prevalence of HIV-related central nervous system (CNS) complications is expected to remain high. Considering the principal role of the brain endothelium in HIV infection of the CNS and HAND, the purpose of this manuscript is to review the current literature on the pathobiology of the brain endothelium structural and functional dysregulation in HIV infection, including in the presence of HIV-1 and viral proteins (gp120, Tat, Nef, and Vpr). We summarize evidence from human and animal studies, in vitro studies, and associated mechanisms. We further summarize evidence of synergy or lack thereof between commonly abused substances (cocaine, methamphetamine, alcohol, tobacco, opioids, and cannabinoids) and HIV- or viral protein-induced BBB injury and dysfunction.

Analysis of Sigma-1 Receptor Antagonist BD1047 Effect on Upregulating Proteins in HIV-1-Infected Macrophages Exposed to Cocaine Using Quantitative Proteomics

HIV-1 infects monocyte-derived macrophages (MDM) that migrate into the brain and secrete virus and neurotoxic molecules, including cathepsin B (CATB), causing cognitive dysfunction. Cocaine potentiates CATB secretion and neurotoxicity in HIV-infected MDM. Pretreatment with BD1047, a sigma-1 receptor antagonist, before cocaine exposure reduces HIV-1, CATB secretion, and neuronal apoptosis. We aimed to elucidate the intracellular pathways modulated by BD1047 in HIV-infected MDM exposed to cocaine. We hypothesized that the Sig1R antagonist BD1047, prior to cocaine, significantly deregulates proteins and pathways involved in HIV-1 replication and CATB secretion that lead to neurotoxicity. MDM culture lysates from HIV-1-infected women treated with BD1047 before cocaine were compared with untreated controls using TMT quantitative proteomics, bioinformatics, Lima statistics, and pathway analyses. Results demonstrate that pretreatment with BD1047 before cocaine dysregulated eighty (80) proteins when compared with the infected cocaine group. We found fifteen (15) proteins related to HIV-1 infection, CATB, and mitochondrial function. Upregulated proteins were related to oxidative phosphorylation (SLC25A-31), mitochondria (ATP5PD), ion transport (VDAC2-3), endoplasmic reticulum transport (PHB, TMED10, CANX), and cytoskeleton remodeling (TUB1A-C, ANXA1). BD1047 treatment protects HIV-1-infected MDM exposed to cocaine by upregulating proteins that reduce mitochondrial damage, ER transport, and exocytosis associated with CATB-induced neurotoxicity.

Viral Endothelial Dysfunction: A Unifying Mechanism for COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible virus with significant global impact, morbidity, and mortality. The SARS-CoV-2 virus may result in widespread organ manifestations including acute respiratory distress syndrome, acute renal failure, thromboembolism, and myocarditis. Virus-induced endothelial injury may cause endothelial activation, increased permeability, inflammation, and immune response and cytokine storm. Endothelial dysfunction is a systemic disorder that is a precursor of atherosclerotic vascular disease that is associated with cardiovascular risk factors and is highly prevalent in patients with atherosclerotic cardiovascular and peripheral disease. Several studies have associated various viral infections including SARS-CoV-2 infection with inflammation, endothelial dysfunction, and subsequent innate immune response and cytokine storm. Noninvasive monitoring of endothelial function and identification of high-risk patients who may require specific therapies may have the potential to improve morbidity and mortality associated with subsequent inflammation, cytokine storm, and multiorgan involvement.

HIV-1 Nef and host proteome analysis: Current perspective

Proteome represents the set of proteins being produced by an organism at a given time. Comparative proteomic profiling of a healthy and diseased state is likely to reflect the dynamics of a disease process. Proteomic techniques are widely used to discover novel biomarkers and decipher mechanisms of HIV-1 pathogenesis. Proteomics is thus emerging as an indispensable tool of monitoring a disease process and intense interactions between HIV-1 and host. Nef is known to regulate various functions in the host to establish the state of infection. This review gives an overview of all proteomic studies done on HIV infection and HIV associated disorders including recent developments in Nef-host proteomic profiling. Here, we propose an emphasis on Nef based proteomic studies. We also discuss the future prospects and the technical and biological challenges involved in proteomic studies. Future studies with Nef related proteomic investigation are likely to identify more targets for diagnosis and therapy.

Proteomics to study macrophage response to viral infection

Viral infections are a major burden to human and animal health. Immune response against viruses consists of innate and adaptive immunity which are both critical for the eradication of the viral infection. The innate immune system is the first line of defense against viral infections. Proper innate immune response is required for the activation of adaptive, humoral and cell-mediated immunity. Macrophages are innate immune cells which have a central role in detecting viral infections including influenza A and human immunodeficiency viruses. Macrophages and other host cells respond to viral infection by modulating their protein expression levels, proteins' posttranslational modifications, as well as proteins' intracellular localization and secretion. Therefore the detailed characterization how viruses dynamically manipulate host proteome is needed for understanding the molecular mechanisms of viral infection. It is critical to identify cellular host factors which are exploited by different viruses, and which are less prone for mutations and could serve as potential targets for novel antiviral compounds. Here, we review how proteomics studies have enhanced our understanding of macrophage response to viral infection with special focus on Influenza A and Human immunodeficiency viruses, and virus infections of swine.

SIGNIFICANCE

Influenza A viruses (IAVs) and human immunodeficiency viruses (HIV) infect annually millions of people worldwide and they form a severe threat to human health. Both IAVs and HIV-1 can efficiently antagonize host response and develop drug-resistant variants. Most current antiviral drugs are directed against viral proteins, and there is a constant need to develop new next-generation drugs targeting host proteins that are essential for viral replication. Porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) are economically important swine pathogens. Both PRRSV and PCV2 cause severe respiratory tract illnesses in swine. IAVs, HIV-1, and swine viruses infect macrophages activating antiviral response against these viruses. Macrophages also have a central role in the replication and spread of these viruses. However, macrophage response to these viruses is incompletely understood. Current proteomics methods can provide a global view of host-response to viral infection which is needed for in-depth understanding the molecular mechanisms of viral infection. Here we review the current proteomics studies on macrophage response to viral infection and provide insight into the global host proteome changes upon viral infection.

HIV-1 gp120 Glycoprotein Interacting with Dendritic Cell-specific Intercellular Adhesion Molecule 3-grabbing Non-integrin (DC-SIGN) Down-Regulates Tight Junction Proteins to Disrupt the Blood Retinal Barrier and Increase Its Permeability

Approximately 70% of HIV-1 infected patients acquire ocular opportunistic infections and manifest eye disorders during the course of their illness. The mechanisms by which pathogens invade the ocular site, however, are unclear. Under normal circumstances, vascular endothelium and retinal pigment epithelium (RPE), which possess a well developed tight junction complex, form the blood-retinal barrier (BRB) to prevent pathogen invasion. We hypothesize that disruption of the BRB allows pathogen entry into ocular sites. The hypothesis was tested using in vitro models. We discovered that human RPE cells could bind to either HIV-1 gp120 glycoproteins or HIV-1 viral particles. Furthermore, the binding was mediated by dendritic cell-specific intercellular adhesion molecule 3-grabbing non-integrin (DC-SIGN) expressed on RPE cells. Upon gp120 binding to DC-SIGN, cellular NF-κB signaling was triggered, leading to the induction of matrix metalloproteinases, which subsequently degraded tight junction proteins and disrupted the BRB integrity. DC-SIGN knockdown or prior blocking with a specific antibody abolished gp120-induced matrix metalloproteinase expression and reduced the degradation of tight junction proteins. This study elucidates a novel mechanism by which HIV, type 1 invades ocular tissues and provides additional insights into the translocation or invasion process of ocular complication-associated pathogens.

Getting into the brain: Potential of nanotechnology in the management of NeuroAIDS

In spite of significant advances in antiretroviral (ARV) therapy, the elimination of human immunodeficiency virus (HIV) reservoirs from the periphery and the central nervous system (CNS) remains a formidable task. The incapability of ARV to go across the blood-brain barrier (BBB) after systemic administration makes the brain one of the dominant HIV reservoirs. Thus, screening, monitoring, and elimination of HIV reservoirs from the brain remain a clinically daunting and key task. The practice and investigation of nanomedicine possesses potentials for therapeutics against neuroAIDS. This review highlights the advancements in nanoscience and nanotechnology to design and develop specific size therapeutic cargo for efficient navigation across BBB so as to recognize and eradicate HIV brain reservoirs. Different navigation and drug release strategies, their biocompatibility and efficacy with related challenges and future prospects are also discussed. This review would be an excellent platform to understand nano-enable multidisciplinary research to formulate efficient nanomedicine for the management of neuroAIDS.

HIV and viral protein effects on the blood brain barrier

The blood brain barrier (BBB) plays a critical role in the normal physiology of the central nervous system (CNS) by regulating what crosses from the periphery into the brain. Damage to the BBB or alterations in transport systems may mediate the pathogenesis of many CNS diseases, including HIV-associated CNS dysfunction. HIV-1 infection can result in neuropathologic changes in about one half of infected individuals and also can result in damage to the BBB. HIV-1 and the HIV-1 viral proteins, Tat and gp120, cause alterations in the integrity and function of the BBB through both paracellular and transcellular mechanisms. The current review discusses HIV and viral protein-mediated injury to the BBB with a focus on the effects on tight junction proteins, barrier permeability, and drug efflux proteins.

Application of "Omics" Technologies for Diagnosis and Pathogenesis of Neurological Infections

Infections of the human nervous system have substantial morbidity and mortality but also represent among the most challenging of all neurological diseases because of the difficulty in establishing a diagnosis and implementing effective therapies. Neurological infections lead to altered expression levels of a wide range of host- and pathogen-derived biomolecules both within and outside of the nervous system. Quantitative analyses of these biomolecular perturbations have been traditionally performed using "classical" molecular or analytical methods, which evaluate one or few genes or their products at a time. Recent technical developments together with the increasing availability of high-throughput/content methodologies have enabled a more comprehensive overview of these molecular alterations and thus provide new approaches to the diagnosis and/or treatment of this group of disorders. Herein, we will review recent evidence pointing to the capacity of the so-called omics techniques in studying the nervous system infections with an emphasis on genomics, transcriptomics, and proteomics technologies.

Tat 101-mediated enhancement of brain pericyte migration involves platelet-derived growth factor subunit B homodimer: implications for human immunodeficiency virus-associated neurocognitive disorders

In the era of antiretroviral therapy, although the human immunodeficiency virus (HIV) replication can be successfully controlled, complications of the CNS continue to affect infected individuals. Viral Tat protein is not only neurotoxic but has also been shown to disrupt the integrity of the blood-brain barrier (BBB). Although the role of brain microvascular endothelial cells and astrocytes in Tat-mediated impairment has been well documented, pericytes, which are important constituents of the BBB and play a key role in maintaining the integrity of the barrier, remain poorly studied in the context of HIV-associated neurocognitive disorders (HAND). In the present study, we demonstrated that exposure of human brain microvascular pericytes and C3H/10T1/2 cells to HIV-1 Tat101 resulted in increased expression of platelet-derived growth factor subunit B homodimer (PDGF-BB) and increased migration of the treated cells. Furthermore, we also demonstrated that this effect of Tat was mediated via activation of mitogen-activated protein kinases and nuclear factor-κB pathways. Secreted PDGF-BB resulted in autocrine activation of the PDGF-BB/PDGF β receptor signaling pathway, culminating ultimately into increased pericyte migration. Ex vivo relevance of these findings was further corroborated in isolated microvessels of HIV Tg26 mice that demonstrated significantly increased expression of PDGF-BB in isolated brain microvessels with a concomitant loss of pericytes. Intriguingly, loss of pericyte coverage was also detected in sections of frontal cortex from humans with HIV-encephalitis compared with the uninfected controls. These findings thus implicate a novel role of PDGF-BB in the migration of pericytes, resulting in loss of pericyte coverage from the endothelium with a subsequent breach of the BBB.

Role of anti-inflammatory compounds in human immunodeficiency virus-1 glycoprotein120-mediated brain inflammation

BACKGROUND

Neuroinflammation is a common immune response associated with brain human immunodeficiency virus-1 (HIV-1) infection. Identifying therapeutic compounds that exhibit better brain permeability and can target signaling pathways involved in inflammation may benefit treatment of HIV-associated neurological complications. The objective of this study was to implement an in vivo model of brain inflammation by intracerebroventricular administration of the HIV-1 viral coat protein gp120 in rats and to examine anti-inflammatory properties of HIV adjuvant therapies such as minocycline, chloroquine and simvastatin.

METHODS

Male Wistar rats were administered a single dose of gp120ADA (500 ng) daily for seven consecutive days, intracerebroventricularly, with or without prior intraperitoneal administration of minocycline, chloroquine or simvastatin. Maraviroc, a CCR5 antagonist, was administered intracerebroventricularly prior to gp120 administration for seven days as control. Real-time qPCR was used to assess gene expression of inflammatory markers in the frontal cortex, hippocampus and striatum. Interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) secretion in cerebrospinal fluid (CSF) was measured applying ELISA. Protein expression of mitogen-activated protein kinases (MAPKs) (extracellular signal-related kinase 1/2 (ERK1/2), c-Jun N-terminal kinases (JNKs) and P38 kinases (P38Ks)) was detected using immunoblot analysis. Student's t-test and ANOVA were applied to determine statistical significance.

RESULTS

In gp120ADA-injected rats, mRNA transcripts of interleukin-1β (IL-1β) and inducible nitric oxide synthase (iNOS) were significantly elevated in the frontal cortex, striatum and hippocampus compared to saline or heat-inactivated gp120-injected controls. In CSF, a significant increase in TNF-α and IL-1β was detected. Maraviroc reduced upregulation of these markers suggesting that the interaction of R5-tropic gp120 to CCR5 chemokine receptor is critical for induction of an inflammatory response. Minocycline, chloroquine or simvastatin attenuated upregulation of IL-1β and iNOS transcripts in different brain regions. In CSF, minocycline suppressed TNF-α and IL-1β secretion, whereas chloroquine attenuated IL-1β secretion. In gp120-injected animals, activation of ERK1/2 and JNKs was observed in the hippocampus and ERK1/2 activation was significantly reduced by the anti-inflammatory agents.

CONCLUSIONS

Our data demonstrate that anti-inflammatory compounds can completely or partially reverse gp120-associated brain inflammation through an interaction with MAPK signaling pathways and suggest their potential role in contributing towards the prevention and treatment of HIV-associated neurological complications.

Bioinformatic analysis of HIV-1 entry and pathogenesis

The evolution of human immunodeficiency virus type 1 (HIV-1) with respect to co-receptor utilization has been shown to be relevant to HIV-1 pathogenesis and disease. The CCR5-utilizing (R5) virus has been shown to be important in the very early stages of transmission and highly prevalent during asymptomatic infection and chronic disease. In addition, the R5 virus has been proposed to be involved in neuroinvasion and central nervous system (CNS) disease. In contrast, the CXCR4-utilizing (X4) virus is more prevalent during the course of disease progression and concurrent with the loss of CD4(+) T cells. The dual-tropic virus is able to utilize both co-receptors (CXCR4 and CCR5) and has been thought to represent an intermediate transitional virus that possesses properties of both X4 and R5 viruses that can be encountered at many stages of disease. The use of computational tools and bioinformatic approaches in the prediction of HIV-1 co-receptor usage has been growing in importance with respect to understanding HIV-1 pathogenesis and disease, developing diagnostic tools, and improving the efficacy of therapeutic strategies focused on blocking viral entry. Current strategies have enhanced the sensitivity, specificity, and reproducibility relative to the prediction of co-receptor use; however, these technologies need to be improved with respect to their efficient and accurate use across the HIV-1 subtypes. The most effective approach may center on the combined use of different algorithms involving sequences within and outside of the env-V3 loop. This review focuses on the HIV-1 entry process and on co-receptor utilization, including bioinformatic tools utilized in the prediction of co-receptor usage. It also provides novel preliminary analyses for enabling identification of linkages between amino acids in V3 with other components of the HIV-1 genome and demonstrates that these linkages are different between X4 and R5 viruses.

Cationic solid lipid nanoparticles with cholesterol-mediated surface layer for transporting saquinavir to the brain

Cholesterol-mediated cationic solid lipid nanoparticles (CSLNs) were formulated with esterquat 1 (EQ 1) and stearylamine as positively charged external layers on hydrophobic internal cores of cacao butter. These CSLNs were employed to deliver saquinavir (SQV) to the brain. The permeability of SQV across the blood-brain barrier (BBB) using SQV-loaded CSLNs (SQV-CSLNs) was estimated with an in vitro model of a monolayer of human brain-microvascular endothelial cells (HBMECs) regulated by human astrocytes. The results revealed that the average diameter of SQV-CSLNs diminished when the weight percentage of cholesterol and EQ 1 increased. The morphological images indicated a uniform size of SQV-CSLNs with compact lipid structure. In addition, an increasing weight percentage of cholesterol and EQ 1 enhanced the zeta potential of SQV-CSLNs. The fluorescent staining demonstrated that HBMECs could internalize SQV-CSLNs. An increase in the weight percentage of cholesterol and EQ 1 also promoted the uptake of SQV-CSLNs by HBMECs. Moreover, a high content of cholesterol and EQ 1 in SQV-CSLNs increased the BBB permeability of SQV. The cholesterol-mediated SQV-CSLNs can be an efficacious drug delivery system for brain-targeting delivery of antiviral agents.

HIV-1 Vpr modulates macrophage metabolic pathways: a SILAC-based quantitative analysis

Human immunodeficiency virus type 1 encoded viral protein Vpr is essential for infection of macrophages by HIV-1. Furthermore, these macrophages are resistant to cell death and are viral reservoir. However, the impact of Vpr on the macrophage proteome is yet to be comprehended. The goal of the present study was to use a stable-isotope labeling by amino acids in cell culture (SILAC) coupled with mass spectrometry-based proteomics approach to characterize the Vpr response in macrophages. Cultured human monocytic cells, U937, were differentiated into macrophages and transduced with adenovirus construct harboring the Vpr gene. More than 600 proteins were quantified in SILAC coupled with LC-MS/MS approach, among which 136 were significantly altered upon Vpr overexpression in macrophages. Quantified proteins were selected and clustered by biological functions, pathway and network analysis using Ingenuity computational pathway analysis. The proteomic data illustrating increase in abundance of enzymes in the glycolytic pathway (pentose phosphate and pyruvate metabolism) was further validated by western blot analysis. In addition, the proteomic data demonstrate down regulation of some key mitochondrial enzymes such as glutamate dehydrogenase 2 (GLUD2), adenylate kinase 2 (AK2) and transketolase (TKT). Based on these observations we postulate that HIV-1 hijacks the macrophage glucose metabolism pathway via the Vpr-hypoxia inducible factor 1 alpha (HIF-1 alpha) axis to induce expression of hexokinase (HK), glucose-6-phosphate dehyrogenase (G6PD) and pyruvate kinase muscle type 2 (PKM2) that facilitates viral replication and biogenesis, and long-term survival of macrophages. Furthermore, dysregulation of mitochondrial glutamate metabolism in macrophages can contribute to neurodegeneration via neuroexcitotoxic mechanisms in the context of NeuroAIDS.

HIV Associated Neurocognitive Disorders

Human immunodeficiency virus type 1 is associated with the development of neurocognitive disorders in many infected individuals, including a broad spectrum of motor impairments and cognitive deficits. Despite extensive research, the pathogenesis of HIV-associated neurocognitive disorders (HAND) is still not clear. This review provides a comprehensive view of HAND, including HIV neuroinvasion, HAND diagnosis and different level of disturbances, influence of highly-active antiretroviral therapy to HIV-associated dementia (HAD), possible pathogenesis of HAD, etc. Together, this review will give a thorough and clear understanding of HAND, especially HAD, which will be vital for future research, diagnosis and treatment.

Functional proteome of macrophage carried nanoformulated antiretroviral therapy demonstrates enhanced particle carrying capacity

Our laboratory developed long-acting nanoformulations of antiretroviral therapy (nanoART) to improve drug compliance, reduce toxicities, and facilitate access of drug to viral reservoirs. These all function to inevitably improve treatment of human immunodeficiency virus (HIV) infection. Formulations are designed to harness the carrying capacities of mononuclear phagocytes (MP; monocytes and macrophages) and to use these cells as Trojan horses for drug delivery. Such a drug distribution system limits ART metabolism and excretion while facilitating access to viral reservoirs. Our prior works demonstrated a high degree of nanoART sequestration in macrophage recycling endosomes with broad and sustained drug tissue biodistribution and depots with limited untoward systemic toxicities. Despite such benefits, the effects of particle carriage on the cells' functional capacities remained poorly understood. Thus, we employed pulsed stable isotope labeling of amino acids in cell culture to elucidate the macrophage proteome and assess any alterations in cellular functions that would affect cell-drug carriage and release kinetics. NanoART-MP interactions resulted in the induction of a broad range of activation-related proteins that can enhance phagocytosis, secretory functions, and cell migration. Notably, we now demonstrate that particle-cell interactions serve to enhance drug loading while facilitating drug tissue depots and transportation.

Cytokine signaling modulates blood-brain barrier function

The blood-brain barrier (BBB) provides a vast interface for cytokines to affect CNS function. The BBB is a target for therapeutic intervention. It is essential, therefore, to understand how cytokines interact with each other at the level of the BBB and how secondary signals modulate CNS functions beyond the BBB. The interactions between cytokines and lipids, however, have not been fully addressed at the level of the BBB. Here, we summarize current understanding of the localization of cytokine receptors and transporters in specific membrane microdomains, particularly lipid rafts, on the luminal (apical) surface of the microvascular endothelial cells composing the BBB. We then illustrate the clinical context of cytokine effects on the BBB by neuroendocrine regulation and amplification of inflammatory signals. Two unusual aspects discussed are signaling crosstalk by different classes of cytokines and genetic regulation of drug efflux transporters. We also introduce a novel area of focus on how cytokines may act through nuclear hormone receptors to modulate efflux transporters and other targets. A specific example discussed is the ATP-binding cassette transporter-1 (ABCA-1) that regulates lipid metabolism. Overall, cytokine signaling at the level of the BBB is a crucial feature of the dynamic regulation that can rapidly change BBB function and affect brain health and disease.

Unique and differential protein signatures within the mononuclear cells of HIV-1 and HCV mono-infected and co-infected patients

BACKGROUND

Pathogenesis of liver damage in patients with HIV and HCV co-infection is complex and multifactorial. Although global awareness regarding HIV-1/HCV co-infection is increasing little is known about the pathophysiology that mediates the rapid progression to hepatic disease in the co-infected individuals.

RESULTS

In this study, we investigated the proteome profiles of peripheral blood mononuclear cells from HIV-1 mono-, HCV mono-, and HIV-1/HCV co-infected patients. The results of high-resolution 2D gel electrophoresis and PD quest software quantitative analysis revealed that several proteins were differentially expressed in HIV-1, HCV, and HIV-1/HCV co-infection. Liquid chromatography-mass spectrometry and Mascot database matching (LC-MS/MS analysis) successfully identified 29 unique and differentially expressed proteins. These included cytoskeletal proteins (tropomyosin, gelsolin, DYPLSL3, DYPLSL4 and profilin-1), chaperones and co-chaperones (HSP90-beta and stress-induced phosphoprotein), metabolic and pre-apoptotic proteins (guanosine triphosphate [GTP]-binding nuclear protein Ran, the detoxifying enzyme glutathione S-transferase (GST) and Rho GDP-dissociation inhibitor (Rho-GDI), proteins involved in cell prosurvival mechanism, and those involved in matrix synthesis (collagen binding protein 2 [CBP2]). The six most significant and relevant proteins were further validated in a group of mono- and co-infected patients (n = 20) at the transcriptional levels.

CONCLUSIONS

The specific pro- and anti- apoptotic protein signatures revealed in this study could facilitate the understanding of apoptotic and protective immune-mediated mechanisms underlying HIV-1 and HCV co-infection and their implications on liver disease progression in co-infected patients.

Nanoparticle based galectin-1 gene silencing, implications in methamphetamine regulation of HIV-1 infection in monocyte derived macrophages

Galectin-1, an adhesion molecule, is expressed in macrophages and implicated in human immunodeficiency virus (HIV-1) viral adsorption. In this study, we investigated the effects of methamphetamine on galectin-1 production in human monocyte derived macrophages (MDM) and the role of galectin-1 in methamphetamine potentiation of HIV-1 infection. Herein we show that levels of galectin-1 gene and protein expression are significantly increased by methamphetamine. Furthermore, concomitant incubation of MDM with galectin-1 and methamphetamine facilitates HIV-1 infection compared to galectin-1 alone or methamphetamine alone. We utilized a nanotechnology approach that uses gold nanorod (GNR)-galectin-1 siRNA complexes (nanoplexes) to inhibit gene expression for galectin-1. Nanoplexes significantly silenced gene expression for galectin-1 and reversed the effects of methamphetamine on galectin-1 gene expression. Moreover, the effects of methamphetamine on HIV-1 infection were attenuated in the presence of the nanoplex in MDM.

Anticlastogenic effect of diosgenin on 7,12-dimethylbenz(a)anthracene treated experimental animals

The present investigation explores the anticlastogenic effect of diosgenin on 7,12-dimethylbenz(a)anthracene (DMBA) treated clastogenesis. The frequency of bone marrow micronucleated polychromatic erythrocytes (MnPCEs), chromosomal aberrations (CA), deoxyribonucleic acid (DNA) damage as cytogenetic markers and the levels of lipid peroxidation by-products, activities of enzymatic antioxidant and the status of detoxification agents were performed to assess the anticlastogenic effects of diosgenin on DMBA treated hamsters. Intraperitoneal injection of DMBA (30 mg/kg bw) leads to clastogenesis in hamster. Elevated MnPCEs frequencies, CA, DNA damage, enhanced lipid peroxidation by products, declined antioxidant activities and detoxification cascade were observed in DMBA treated hamsters. Oral pretreatment with diosgenin (80 mg/kg bw) daily for a period of five days significantly reduced the frequency of MnPCEs, CA, DNA damage and normalized the levels of lipid peroxidation by products with increased activities of antioxidants and detoxification agents in DMBA alone treated hamsters. Outcome of the present study revealed that diosgenin has potent anticlastogenic effects on DMBA treated hamsters.

Mass spectrometry based proteomic studies on viruses and hosts--a review

In terms of proteomic research in the 21st century, the realm of virology is still regarded as an enormous challenge mainly brought by three aspects, namely, studying on the complex proteome of the virus with unexpected variations, developing more accurate analytical techniques as well as understanding viral pathogenesis and virus-host interaction dynamics. Progresses in these areas will be helpful to vaccine design and antiviral drugs discovery. Mass spectrometry based proteomics have shown exceptional display of capabilities, not only precisely identifying viral and cellular proteins that are functionally, structurally, and dynamically changed upon virus infection, but also enabling us to detect important pathway proteins. In addition, many isolation and purification techniques and quantitative strategies in conjunction with MS can significantly improve the sensitivity of mass spectrometry for detecting low-abundant proteins, replenishing the stock of virus proteome and enlarging the protein-protein interaction maps. Nevertheless, only a small proportion of the infectious viruses in both of animal and plant have been studied using this approach. As more virus and host genomes are being sequenced, MS-based proteomics is becoming an indispensable tool for virology. In this paper, we provide a brief review of the current technologies and their applications in studying selected viruses and hosts.

Regulation of P-glycoprotein by human immunodeficiency virus-1 in primary cultures of human fetal astrocytes

P-glycoprotein (P-gp), a drug efflux pump, is known to alter the bioavailability of antiretroviral drugs at several sites, including the brain. We have previously shown that human immunodeficiency virus-1 (HIV-1) glycoprotein 120 (gp120) induces proinflammatory cytokine secretion and decreases P-gp functional expression in rat astrocytes, a cellular reservoir of HIV-1. However, whether P-gp is regulated in a similar way in human astrocytes is unknown. This study investigates the regulation of P-gp in an in vitro model of gp120-triggered human fetal astrocytes (HFAs). In this system, elevated levels of interleukin-6 (IL-6), IL-1β, and tumor necrosis factor-α were detected in culture supernatants. Pretreatment with CCR5 neutralizing antibody attenuated cytokine secretion, suggesting that gp120-CCR5 interaction mediated cytokine production. Treatment with gp120 (R5-tropic) resulted in reduced P-gp expression (64%) and function as determined by increased (1.6-fold) cellular accumulation of [(3) H]digoxin, a P-gp substrate. Exposure to R5 or R5/X4-tropic viral isolates led to a downregulation in P-gp expression (75% or 90%, respectively), and treatment with IL-6 also showed lower P-gp expression (50%). Moreover, IL-6 neutralizing antibody blocked gp120-mediated P-gp downregulation, suggesting that IL-6 is a key modulator of P-gp. Gp120- or IL-6-mediated downregulation of P-gp was attenuated by SN50 (a nuclear factor-κB [NF-κB] inhibitor), suggesting involvement of NF-κB signaling in P-gp regulation. Our results suggest that, similarly to the case with rodent astrocytes, pathophysiological stressors associated with brain HIV-1 infection have a downregulatory effect on P-gp functional expression in human astrocytes, which may ultimately result in altered antiretroviral drug accumulation within brain parenchyma.

Cerebral microvascular endothelium and the pathogenesis of neurodegenerative diseases

Diseases of the central nervous system (CNS) pose a significant health challenge, but despite their diversity, they share many common features and mechanisms. For example, endothelial dysfunction has been implicated as a crucial event in the development of several CNS disorders, such as Alzheimer disease, Parkinson disease, amyotrophic lateral sclerosis, multiple sclerosis, human immunodeficiency virus (HIV)-1-associated neurocognitive disorder and traumatic brain injury. Breakdown of the blood–brain barrier (BBB) as a result of disruption of tight junctions and transporters, leads to increased leukocyte transmigration and is an early event in the pathology of these disorders. The brain endothelium is highly reactive because it serves as both a source of, and a target for, inflammatory proteins and reactive oxygen species. BBB breakdown thus leads to neuroinflammation and oxidative stress, which are implicated in the pathogenesis of CNS disease. Furthermore, the physiology and pathophysiology of endothelial cells are closely linked to the functioning of their mitochondria, and mitochondrial dysfunction is another important mediator of disease pathology in the brain. The high concentration of mitochondria in cerebrovascular endothelial cells might account for the sensitivity of the BBB to oxidant stressors. Here, we discuss how greater understanding of the role of BBB function could lead to new therapeutic approaches for diseases of the CNS that target the dynamic properties of brain endothelial cells.

Proteomic analysis of HIV-infected macrophages

Mononuclear phagocytes (monocytes, macrophages, and microglia) play an important role in innate immunity against pathogens including HIV. These cells are also important viral reservoirs in the central nervous system and secrete inflammatory mediators and toxins that affect the tissue environment and function of surrounding cells. In the era of antiretroviral therapy, there are fewer of these inflammatory mediators. Proteomic approaches including surface enhancement laser desorption ionization, one- and two-dimensional difference in gel electrophoresis, and liquid chromatography tandem mass spectrometry have been used to uncover the proteins produced by in vitro HIV-infected monocytes, macrophages, and microglia. These approaches have advanced the understanding of novel mechanisms for HIV replication and neuronal damage. They have also been used in tissue macrophages that restrict HIV replication to understand the mechanisms of restriction for future therapies. In this review, we summarize the proteomic studies on HIV-infected mononuclear phagocytes and discuss other recent proteomic approaches that are starting to be applied to this field. As proteomic instruments and methods evolve to become more sensitive and quantitative, future studies are likely to identify more proteins that can be targeted for diagnosis or therapy and to uncover novel disease mechanisms.

HIV-1 and the macrophage

Macrophages and CD4+ T cells are natural target cells for HIV-1, and both cell types contribute to the establishment of the viral reservoir that is responsible for continuous residual virus replication during antiretroviral therapy and viral load rebound upon treatment interruption. Scientific findings that support a critical role for the infected monocyte/macrophage in HIV-1-associated diseases, such as neurological disorders and cardiovascular disease, are accumulating. To prevent or treat these HIV-1-related diseases, we need to halt HIV-1 replication in the macrophage reservoir. This article describes our current knowledge of how monocytes and certain macrophage subsets are able to restrict HIV-1 infection, in addition to what makes macrophages respond less well to current antiretroviral drugs as compared with CD4+ T cells. These insights will help to find novel approaches that can be used to meet this challenge.

Morphine treatment of human monocyte-derived macrophages induces differential miRNA and protein expression: impact on inflammation and oxidative stress in the central nervous system

HIV-1-infected opiate abusers often exhibit an accelerated form of HIV-1-associated dementia and enhanced neurological dysfunction. Productive HIV-1 infection of microglia and perivascular macrophages and the resultant secretion of neurotoxic molecules by these cells contribute to this phenomenon. In order to understand the role of morphine in this process, we performed a genome-wide association study at the micro RNA (miRNA) and protein levels in human monocyte-derived macrophages (h-mdms). A total of 26 differentially expressed miRNA were identified (P < 0.01), of which hsa-miR-15b and hsa-miR-181b had the greatest increase and decrease in expression levels, respectively. Computational analysis predicted fibroblast growth factor-2 (FGF-2) as the strongest target gene for hsa-miR15b. Of note, we observed a decrease in FGF-2 protein expression in response to morphine. Both hsa-miR-15b and hsa-miR-181b have several predicted gene targets involved in inflammation and T-cell activation pathways. In this context, we observed induction of MCP-2 and IL-6 by morphine. Moreover, proteomic analysis revealed the induction of mitochondrial superoxide dismutase in response to morphine treatment. HIV-1 infection did not induce mitochondrial superoxide dismutase. Collectively, these observations demonstrate that morphine induces inflammation and oxidative stress in h-mdms thereby contributing to expansion of HIV-1 CNS reservoir expansion and disease progression. Of note, differentially expressed miRNAs (hsa-miR-15b and 181-b) may have a potential role in regulating these processes.

Host proteome research in HIV infection

Proteomics has been widely used in the last few years to look for new biomarkers and decipher the mechanism of HIV–host interaction. Herein, we review the recent developments of HIV/AIDS proteomic research, including the samples used in HIV/AIDS related research, the technologies used for proteomic study, the diagnosis biomarkers of HIV-associated disease especially HIV-associated neurocognitive impairment, the mechanisms of HIV–host interaction, HIV-associated dementia, substance abuse, and so on. In the end of this review, we also give some prospects about the limitation and future improvement of HIV/AIDS proteomic research.

First evidence of overlaps between HIV-Associated Dementia (HAD) and non-viral neurodegenerative diseases: proteomic analysis of the frontal cortex from HIV+ patients with and without dementia

Background

The pathogenesis of HIV-associated dementia (HAD) is poorly understood. To date, detailed proteomic fingerprinting directly from autopsied brain tissues of HAD and HIV non-dementia patients has not been performed.

Result

Here, we have analyzed total proteins from the frontal cortex of 9 HAD and 5 HIV non-dementia patients. Using 2-Dimensional differential in-gel electrophoresis (2-DIGE) to analyze the brain tissue proteome, 76 differentially expressed proteins (p < 0.05; fold change>1.25) were identified between HAD and HIV non-dementia patients, of which 36 protein spots (based on 3D appearance of spots on the images) were chosen for the mass spectrometry analysis. The large majority of identified proteins were represented in the energy metabolic (mitochondria) and signal transduction pathways. Furthermore, over 90% of the protein candidates are common to both HAD and other non-viral neurodegenerative disease, such as Alzheimer's disease. The data was further validated using specific antibodies to 4 proteins (CA2, GS, CKMT and CRMP2) by western blot (WB) in the same samples used for 2D-DIGE, with additional confirmation by immunohistochemitsry (IHC) using frontal lobe tissue from different HAD and HIV+ non-dementia patients. The validation for all 4 antibodies by WB and IHC was in concordance with the DIGE results, lending further credence to the current findings.

Conclusion

These results suggest not only convergent pathogenetic pathways for the two diseases but also the possibility of increased Alzheimer's disease (AD) susceptibility in HAD patients whose life expectancy has been significantly increased by highly active antiretroviral therapy.

Looking at the blood-brain barrier: molecular anatomy and possible investigation approaches

The blood-brain barrier (BBB) is a dynamic and complex interface between blood and the central nervous system that strictly controls the exchanges between the blood and brain compartments, therefore playing a key role in brain homeostasis and providing protection against many toxic compounds and pathogens. In this review, the unique properties of brain microvascular endothelial cells and intercellular junctions are examined. The specific interactions between endothelial cells and basement membrane as well as neighboring perivascular pericytes, glial cells and neurons, which altogether constitute the neurovascular unit and play an essential role in both health and function of the central nervous system, are also explored. Some relevant pathways across the endothelium, as well as mechanisms involved in the regulation of BBB permeability, and the emerging role of the BBB as a signaling interface are addressed as well. Furthermore, we summarize some of the experimental approaches that can be used to monitor BBB properties and function in a variety of conditions and have allowed recent advances in BBB knowledge. Elucidation of the molecular anatomy and dynamics of the BBB is an essential step for the development of new strategies directed to maintain or restore BBB integrity and barrier function and ultimately preserve the delicate interstitial brain environment.

Molecular mechanisms of neuroinvasion by monocytes-macrophages in HIV-1 infection

HIV associated neurocognitive disorders and their histopathological correlates largely depend on the continuous seeding of the central nervous system with immune activated leukocytes, mainly monocytes/macrophages from the periphery. The blood-brain-barrier plays a critical role in this never stopping neuroinvasion, although it appears unaltered until the late stage of HIV encephalitis. HIV flux that moves toward the brain thus relies on hijacking and exacerbating the physiological mechanisms that govern blood brain barrier crossing rather than barrier disruption. This review will summarize the recent data describing neuroinvasion by HIV with a focus on the molecular mechanisms involved.

Nanotechnology applications for improved delivery of antiretroviral drugs to the brain

Human immunodeficiency virus (HIV) can gain access to the central nervous system during the early course of primary infection. Once in the brain compartment the virus actively replicates to form an independent viral reservoir, resulting in debilitating neurological complications, latent infection and drug resistance. Current antiretroviral drugs (ARVs) often fail to effectively reduce the HIV viral load in the brain. This, in part, is due to the poor transport of many ARVs, in particular protease inhibitors, across the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSBF). Studies have shown that nanocarriers including polymeric nanoparticles, liposomes, solid lipid nanoparticles (SLN) and micelles can increase the local drug concentration gradients, facilitate drug transport into the brain via endocytotic pathways and inhibit the ATP-binding cassette (ABC) transporters expressed at the barrier sites. By delivering ARVs with nanocarriers, significant increase in the drug bioavailability to the brain is expected to be achieved. Recent studies show that the specificity and efficiency of ARVs delivery can be further enhanced by using nanocarriers with specific brain targeting, cell penetrating ligands or ABC-transporters inhibitors. Future research should focus on achieving brain delivery of ARVs in a safe, efficient, and yet cost-effective manner.

The regulation of leucocyte transendothelial migration by endothelial signalling events

Leucocytes use sophisticated mechanisms to cross the endothelium lining the vasculature. This is initiated by chemokine- and adhesion molecule-induced intracellular signalling that controls adhesion, spreading, and motility. At the same time, adherent leucocytes trigger the endothelium, manipulating the barrier to promote their transmigration into the underlying tissues. Over the past years, our insights in the associated signalling events within the endothelium have increased considerably, albeit the order of events, their crosstalk, and the consequences for endothelial cells and leucocytes are only partially resolved. Here, we briefly review endothelial signalling that is initiated at the apical endothelial membrane, where the first contact with the leucocytes takes place and signal transduction is induced. In addition, we discuss subsequent events at endothelial cell-cell junctions insofar as they have been linked to transendothelial migration. Finally, we briefly touch upon the modulation of endothelial signalling by infectious pathogens, since these have developed additional, elegant ways to manipulate the endothelium and transendothelial migration that may provide new, relevant insights into this process.

Biomarkers of HIV-1-associated neurocognitive disorders: challenges of proteomic approaches

HIV-1 enters the brain shortly after infection, which may lead to neurological complications and in the most severe cases to encephalitis, dementia and death. The introduction of antiretroviral therapy reduced the incidence of the most severe conditions, nevertheless, approximately half of those infected with this virus will suffer to various degrees from HIV-1-associated neurocognitive disorders. Despite many years of research, there are no biomarkers that can objectively measure and, more importantly, predict the onset and the tempo of HIV-1-associated neurocognitive disorders. Here we review biomarker candidates of neurocognitive impairment due to HIV infection of the brain that have been proposed during the last two decades, and discuss perspectives and limitations of proteomic approaches in the search for new, more sensitive and specific biomarkers.

A coat of many colors: neuroimmune crosstalk in human immunodeficiency virus infection

The use of antiretroviral therapy has reduced mortality and increased the quality of life of HIV-1-infected people, particularly in more developed countries where access to treatment is more widespread. However, morbidities continue, which include HIV-1-associated neurocognitive disorders (HAND). Subtle cognitive abnormalities and low-level viral replication underlie disease. The balance between robust antiviral adaptive immunity, neuronal homeostatic mechanisms, and neuroprotective factors on one hand and toxicities afforded by dysregulated immune activities on the other govern disease. New insights into the pathobiological processes for neuroimmune-linked disease and ways to modulate such activities for therapeutic gain are discussed. Better understanding of the complexities of immune regulation during HAND can improve diagnosis and disease outcomes but is also relevant for the pathogenesis of a broad range of neurodegenerative disorders.

Proteomic studies of nitrated alpha-synuclein microglia regulation by CD4+CD25+ T cells

Microglial inflammatory responses affect Parkinson's disease (PD) associated nigrostriatal degeneration. This is triggered, in measure, by misfolded, nitrated alpha-synuclein (N-alpha-syn) contained within Lewy bodies that are released from dying or dead dopaminergic neurons into the extravascular space. N-alpha-syn-stimulated microglial immunity is regulated by CD4+ T cell subset. Indeed, CD4+CD25+ regulatory T cells (Treg) induce neuroprotective immune responses. This is seen in rodent models of stroke, amyotrophic lateral sclerosis, human immunodeficiency virus associated neurocognitive disorders, and PD. To elucidate the mechanism for Treg-mediated microglial neuroregulatory responses, we used a proteomic platform integrating difference gel electrophoresis and tandem mass spectrometry peptide sequencing. These tests served to determine consequences of Treg on the N-alpha-syn stimulated microglia. The data demonstrated that Treg substantially alter the microglial proteome in response to N-alpha-syn. This is seen through Treg abilities to suppress microglial proteins linked to cell metabolism, migration, protein transport and degradation, redox biology, cytoskeletal, and bioenergetic activities. We conclude that Treg modulate the N-alpha-syn microglial proteome and, in this way, can slow the tempo and course of PD.

Understanding the blood-brain barrier using gene and protein expression profiling technologies

The blood-brain barrier (BBB) contributes to the brain homeostasis by regulating the passage of endogenous and exogenous compounds. This function is in part due to well-known proteins such as tight junction proteins, plasma membrane transporters and metabolic barrier proteins. Over the last decade, genomics and proteomics have emerged as supplementary tools for BBB research. The development of genomic and proteomic technologies has provided several means to extend the BBB knowledge and to investigate additional routes for the bypass of this barrier. These profiling technologies have been used on BBB models to decipher the physiological characteristics and, under stress conditions, to understand the molecular mechanisms of brain diseases. In this review, we will report and discuss the genomic and proteomic studies recently carried out to enhance the understanding of BBB features.

NanoART, neuroAIDS and CNS drug delivery

A broad range of nanomedicines is being developed to improve drug delivery for CNS disorders. The structure of the blood-brain barrier (BBB), the presence of efflux pumps and the expression of metabolic enzymes pose hurdles for drug-brain entry. Nanoformulations can circumvent the BBB to improve CNS-directed drug delivery by affecting such pumps and enzymes. Alternatively, they can be optimized to affect their size, shape, and protein and lipid coatings to facilitate drug uptake, release and ingress across the barrier. This is important as the brain is a sanctuary for a broad range of pathogens including HIV-1. Improved drug delivery to the CNS would affect pharmacokinetic and drug biodistribution properties. This article focuses on how nanotechnology can serve to improve the delivery of antiretroviral medicines, termed nanoART, across the BBB and affect the biodistribution and clinical benefit for HIV-1 disease.

Proteomic characterization of HIV-modulated membrane receptors, kinases and signaling proteins involved in novel angiogenic pathways

Background

Kaposi's sarcoma (KS), hemangioma, and other angioproliferative diseases are highly prevalent in HIV-infected individuals. While KS is etiologically linked to the human herpesvirus-8 (HHV8) infection, HIV-patients without HHV-8 and those infected with unrelated viruses also develop angiopathies. Further, HIV-Tat can activate protein-tyrosine-kinase (PTK-activity) of the vascular endothelial growth factor receptor involved in stimulating angiogenic processes. However, Tat by itself or HHV8-genes alone cannot induce angiogenesis in vivo unless specific proteins/enzymes are produced synchronously by different cell-types. We therefore tested a hypothesis that chronic HIV-replication in non-endothelial cells may produce novel factors that provoke angiogenic pathways.

Methods

Genome-wide proteins from HIV-infected and uninfected T-lymphocytes were tested by subtractive proteomics analyses at various stages of virus and cell growth in vitro over a period of two years. Several thousand differentially regulated proteins were identified by mass spectrometry (MS) and >200 proteins were confirmed in multiple gels. Each protein was scrutinized extensively by protein-interaction-pathways, bioinformatics, and statistical analyses.

Results

By functional categorization, 31 proteins were identified to be associated with various signaling events involved in angiogenesis. 88% proteins were located in the plasma membrane or extracellular matrix and >90% were found to be essential for regeneration, neovascularization and angiogenic processes during embryonic development.

Conclusion

Chronic HIV-infection of T-cells produces membrane receptor-PTKs, serine-threonine kinases, growth factors, adhesion molecules and many diffusible signaling proteins that have not been previously reported in HIV-infected cells. Each protein has been associated with endothelial cell-growth, morphogenesis, sprouting, microvessel-formation and other biological processes involved in angiogenesis (p = 10^-4 to 10^-12). Bioinformatics analyses suggest that overproduction of PTKs and other kinases in HIV-infected cells has suppressed VEGF/VEGFR-PTK expression and promoted VEGFR-independent pathways. This unique mechanism is similar to that observed in neovascularization and angiogenesis during embryogenesis. Validation of clinically relevant proteins by gene-silencing and translational studies in vivo would identify specific targets that can be used for early diagnosis of angiogenic disorders and future development of inhibitors of angiopathies. This is the first comprehensive study to demonstrate that HIV-infection alone, without any co-infection or treatment, can induce numerous "embryonic" proteins and kinases capable of generating novel VEGF-independent angiogenic pathways.

HIV-1 transforms the monocyte plasma membrane proteome

How HIV-1 affects the monocyte proteome is incompletely understood. We posit that one functional consequence of virus-exposure to the monocyte is the facilitation of protein transformation from the cytosol to the plasma membrane (PM). To test this, cell surface labeling with CyDye fluorophores followed by 2 dimensional differential in-gel electrophoresis (2D DIGE) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was performed. Fifty three percent of HIV-1 induced proteins were PM associated. These were linked, in large measure, to cellular activation and oxidative stress. They included, but not limited to, biliverdin reductase, leukotriene hydrolase A(4), heat shock protein 70, and cystatin B. HIV-1 induced PM protein translocation was associated with cathepsin B- and caspase 9, 3-dependent apoptosis. In contrast, PMA-treated monocytes bypassed caspase 3, 9 pathways and lead to cathepsin B-dependent necrosis. These results demonstrate that HIV-1 uniquely affects monocyte activation and oxidative stress. These do not affect viral infection dynamics but are linked to stress-induced cell death.

Virulence in Cryptococcus species

Cryptococcus neoformans and Cryptococcus gattii are the cause of life-threatening meningoencephalitis in immunocompromised and immunocompetent individuals respectively. The increasing incidence of cryptococcal infection as a result of the AIDS epidemic, the recent emergence of a hypervirulent cryptococcal strain in Canada and the fact that mortality from cryptococcal disease remains high have stimulated intensive research into this organism. Here we outline recent advances in our understanding of C. neoformans and C. gattii, including intraspecific complexity, virulence factors, and key signaling pathways. We discuss the molecular basis of cryptococcal virulence and the interaction between these pathogens and the host immune system. Finally, we discuss future challenges in the study and treatment of cryptococcosis.

Cannabinoids inhibit HIV-1 Gp120-mediated insults in brain microvascular endothelial cells

HIV-1 infection has significant effect on the immune system as well as on the nervous system. Breakdown of the blood-brain barrier (BBB) is frequently observed in patients with HIV-associated dementia (HAD) despite lack of productive infection of human brain microvascular endothelial cells (HBMEC). Cellular products and viral proteins secreted by HIV-1 infected cells, such as the HIV-1 Gp120 envelope glycoprotein, play important roles in BBB impairment and HIV-associated dementia development. HBMEC are a major component of the BBB. Using cocultures of HBMEC and human astrocytes as a model system for human BBB as well as in vivo model, we show for the first time that cannabinoid agonists inhibited HIV-1 Gp120-induced calcium influx mediated by substance P and significantly decreased the permeability of HBMEC as well as prevented tight junction protein down-regulation of ZO-1, claudin-5, and JAM-1 in HBMEC. Furthermore, cannabinoid agonists inhibited the transmigration of human monocytes across the BBB and blocked the BBB permeability in vivo. These results demonstrate that cannabinoid agonists are able to restore the integrity of HBMEC and the BBB following insults by HIV-1 Gp120. These studies may lead to better strategies for treatment modalities targeted to the BBB following HIV-1 infection of the brain based on cannabinoid pharmacotherapies.

HIV-associated neurocognitive disorders and the impact of combination antiretroviral therapies

HIV-associated neurocognitive disorders (HAND) are the most common preventable and treatable cause of dementia. While the incidence of the most severe form of HAND, HIV-associated dementia, has decreased since the introduction of combination antiretroviral therapy (cART), the prevalence of less severe forms of HAND has continued to rise. HAND leads to a subcortical dementia consisting of a triad of cognitive, behavior, and motor dysfunction. No single laboratory test can establish HAND, but ancillary studies including neuropsychological testing, neuroimaging studies, and cerebrospinal fluid (CSF) analysis are useful for supporting or refuting the diagnosis. More recent evidence has suggested that higher central nervous system-penetrating cART may lead to greater suppression of CSF HIV viral loads and improved cognition. Because viral control generally has been successful without eliminating cognitive dysfunction, further clinical studies that assess adjunctive neuroprotective drugs are likely to be required.

HIV-1-infected astrocytes and the microglial proteome

The human immunodeficiency virus (HIV) invades the central nervous system early after viral exposure but causes progressive cognitive, behavior, and motor impairments years later with the onset of immune deficiency. Although in the brain, HIV preferentially replicates productively in cells of mononuclear phagocyte (MP; blood borne macrophage and microglia), astrocytes also can be infected, at low and variable frequency, particularly in patients with encephalitis. Among their many functions, astrocytes network with microglia to provide the first line of defense against microbial infection; however, very little is known about astrocytes' consequences on MP. Here, we addressed this question using co-culture systems of HIV-infected mouse astrocytes and microglia. Pseudotyped vesicular stomatis virus/HIV was used to circumvent the absence of viral receptors and ensure cell genotypic uniformity for studies of intercellular communication. The study demonstrated that infected astrocytes show modest changes in protein elements compared to uninfected cells. In contrast, infected astrocytes induce robust changes in the proteome of HIV-1-infected microglia. Accelerated cell death and redox proteins, among others, were produced in abundance. The observations confirmed the potential of astrocytes to influence the neuropathogenesis of HIV-1 infection by specifically altering the neurotoxic potential of infected microglia and regulating viral maturation.

Retroviral proteomics and interactomes: intricate balances of cell survival and viral replication

Overall changes in the host cellular proteome upon retroviral infection intensify from the initial entry of the virus to the incorporation of viral DNA into the host genome, and finally to the consistent latent state of infection. The host cell reacts to both the entry of viral elements and the manipulation of host cellular machinery, resulting in a cascade of signaling events and pathway activation. Cell type- and tissue-specific responses are also characteristic of infection and can be classified based on the differential expression of genes and proteins between normal and disease states. The characterization of differentially expressed proteins upon infection is also critical in identifying potential biomarkers within infected bodily fluids. Biomarkers can be used to monitor the progression of infection, track the effectiveness of specific treatments and characterize the mechanisms of disease pathogenesis. Standard proteomic approaches have been applied to monitor the changes in global protein expression and localization in infected cells, tissues and fluids. Here we report on recent investigations into the characterization of proteomes in response to retroviral infection.