HIV-1/cocaine induced oxidative stress disrupts tight junction protein-1 in human pulmonary microvascular endothelial cells: role of Ras/ERK1/2 pathway

The coexistence of aflatoxin M1 and ochratoxin A induced intestinal barrier disruption via the regulation of key differentially expressed microRNAs and long non-coding RNAs in BALB/c mice

Food safety can be seriously threatened by the existence of both aflatoxin M1 (AFM1) and ochratoxin A (OTA) in milk and corresponding products. The importance of intestine integrity in preserving human health is widely understood in vitro, but the fundamental processes by which AFM1 and OTA cause disruption of the intestinal barrier are as yet unknown, especially in vivo. Based on the analysis of the whole transcriptome of BALB/c mice, the competing endogenous RNA (ceRNA) regulation network was obtained in the current study. Each of 12 mice were separated into five treatments: saline solution treatment, 1.0% DMSO vehicle control treatment, 3.0 mg/kg b.w. individual AFM1 treatment (AFM1), 3.0 mg/kg b.w. individual OTA treatment (OTA), and combined mycotoxins treatment (AFM1 +OTA). The study period lasted 28 days. The jejunum tissue was collected for the histological assessment and whole transcriptome analysis, and the whole blood was collected, and determination of serum biochemical indicators. The phenotypic results demonstrated that AFM1 and OTA caused intestinal barrier disruption via an increased apoptosis level and decreased expression of tight junction (TJ) proteins. The ceRNA network demonstrated that AFM1 and OTA induced cell apoptosis through activating the expression of DUSP9 and suppressing the expression of PLA2G2D, which were regulated by differentially expressed microRNAs (DEmiRNAs) (miR-124-y, miR-194-z, miR-224-x, and miR-452-x) and differentially expressed long non-coding RNAs (DElncRNAs) (FUT8 and GPR31C). And AFM1 and OTA decreased TJ proteins via inhibiting the expression of PAK6, which was regulated by several important DEmiRNAs and DElncRNAs. These DE RNAs in intestinal integrity were involved in MAPK and Ras signaling pathway. Overall, our findings expand the current knowledge regarding the potential mechanisms of intestinal integrity disruption brought on by AFM1 and OTA in vivo.

HIV and Drug Use: A Tale of Synergy in Pulmonary Vascular Disease Development

Over the past two decades, with the advent and adoption of highly active anti-retroviral therapy, HIV-1 infection, a once fatal and acute illness, has transformed into a chronic disease with people living with HIV (PWH) experiencing increased rates of cardio-pulmonary vascular diseases including life-threatening pulmonary hypertension. Moreover, the chronic consequences of tobacco, alcohol, and drug use are increasingly seen in older PWH. Drug use, specifically, can have pathologic effects on the cardiovascular health of these individuals. The "double hit" of drug use and HIV may increase the risk of HIV-associated pulmonary arterial hypertension (HIV-PAH) and potentiate right heart failure in this population. This article explores the epidemiology and pathophysiology of PAH associated with HIV and recreational drug use and describes the proposed mechanisms by which HIV and drug use, together, can cause pulmonary vascular remodeling and cardiopulmonary hemodynamic compromise. In addition to detailing the proposed cellular and signaling pathways involved in the development of PAH, this article proposes areas ripe for future research, including the influence of gut dysbiosis and cellular senescence on the pathobiology of HIV-PAH. © 2023 American Physiological Society. Compr Physiol 13:4659-4683, 2023.

Cocaine administration protects gut mucosa barrier and reduces plasma level of TNF-α

Background

Cocaine affects not only the central nervous system, but also systemic immunity. The role of cocaine in gut mucosal integrity is not fully understood.

Methods

Here we evaluated the effect of cocaine use on gut endothelial permeability and system inflammation in rats that self-administered cocaine or saline and in humans using immunohistochemistry, qPCR, ELISA, and Transepithelial/transendothelial electrical resistance (TEER).

Results

Cocaine administration maintained intact and undisturbed intestinal mucosal structures, increased tight junction claudin 1 and 2 mRNA expression, and decreased plasma TNF-α levels, compared to the control group, at the end of study in rats. Further, cocaine treatment decreased gut endothelial permeability in a dose-dependent manner in human epithelial Caco-2 cells in vitro. Consistently, chronic cocaine users exhibited decreased plasma levels of TNF-α compared with non-drug users in vivo. However, plasma IL-6 levels were similar between cocaine use and control groups both in humans and rats in vivo.

Conclusions

Our results from both human and rat studies in vivo and in vitro suggest that cocaine use may exert a protective effect on the integrity of gut mucosa and suppresses plasma TNF-α levels. This study may provide information on some beneficial effects of cocaine use on gut endothelial cells integrity and systemic inflammation.

An Outlook on the Etiopathogenesis of Pulmonary Hypertension in HIV

Although overall survival rates of patients infected with human immunodeficiency virus (HIV) have been significantly improved by antiretroviral therapy (ART), chronic comorbidities associated with HIV result in a worsening quality of life. Pulmonary arterial hypertension (PAH) is the most prevalent comorbidity associated with HIV infection. Despite low viremia and a non-replicative state maintained by ART, few people develop PAH. Previous data from animal models and human pulmonary microvascular endothelial cells (HPMVECs) suggests a constellation of events occurring during the propagation of HIV-associated PAH (HIV-PAH). However, these studies have not successfully isolated HIV virions, HIV-DNA, protein 24 antigen (p24), or HIV-RNA from the pulmonary endothelial cells (ECs). It provides an insight into an ongoing inflammatory process that could be attributed to viral proteins. Several studies have demonstrated the role of viral proteins on vascular remodeling. A composite of chronic inflammatory changes mediated by cytokines and growth factors along with several inciting risk factors such as Hepatitis C virus (HCV) co-infection, genetic factors, male predominance, illegal drug usage, and duration of HIV infection have led to molecular changes that result in an initial phase of apoptosis followed by the formation of apoptotic resistant hyperproliferative ECs with altered phenotype. This study aims to identify the risk factors and mechanisms behind HIV-PAH pathobiology at the host-pathogen interface at the intracellular level.

Differential Expression Profile of microRNAs and Tight Junction in the Lung Tissues of Rat With Mitomycin-C-Induced Pulmonary Veno-Occlusive Disease

Background

Pulmonary veno-occlusive disease (PVOD) is characterized by increased pulmonary vascular resistance. Currently, there is a lack of effective treatment. It is of great significance to explore molecular targets for treatment. This study investigated the differential expression profile of miRNAs and tight junction in the lung tissues of rats with mitomycin-C (MMC)-induced PVOD.

Methods

A total of 14 rats were divided into the control group and he PVOD group. We measured mean pulmonary arterial pressure (mPAP) and right ventricular hypertrophy index (RVHI). Pathological changes including those in lung tissues, pulmonary venules, and capillary were detected by H&E and orcein staining. Western blot was used to detect GCN2, ZO-1, occludin, and claudin-5 expression. We analyzed the miRNAs profile in the rat lung tissues by high-throughput sequencing. The top differentially expressed miRNAs were validated by using real-time polymerase chain reaction (RT-PCR).

Results

There were severe pulmonary artery hypertrophy/hyperplasia, thickening, and occlusion in the small pulmonary veins, pulmonary edema, and dilated capillaries in MMC-induced rats with PVOD. In addition, mPAP and RVHI were significantly increased (P < 0.05). The expression of GCN2 was significantly decreased (P < 0.05). A total of 106 differentially expressed miRNAs were identified. According to the fold changes, the top ten upregulated miRNAs were miRNA-543-3p, miRNA-802-5p, miRNA-493-3p, miRNA-539-3p, miRNA-495, miRNA-380-5p, miRNA-214-5p, miRNA-539-5p, miRNA-190a-3p, and miRNA-431. The top 10 downregulated miRNAs were miRNA-201-3p, miRNA-141-3p, miRNA-1912-3p, miRNA-500-5p, miRNA-3585-5p, miRNA-448-3p, miRNA-509-5p, miRNA-3585-3p, miRNA-449c-5p, and miRNA-509-3p. RT-PCR confirmed that miRNA-214-5p was upregulated, while miRNA-141-3p was downregulated (P < 0.05). Functional analysis showed various signaling pathways and metabolic processes, such as fatty acid biosynthesis, tight junction, and the mTOR signaling pathway. In addition, the expression of the tight junction-related protein of ZO-1, occludin, and claudin-5 was significantly decreased in rats with PVOD (P < 0.05).

Conclusion

miRNAs may be involved in the pathogenesis of PVOD. Furthermore, ZO-1, occludin, and claudin-5 verification confirmed that the tight junction may be involved in the development of the disease.

Impact of human immunodeficiency virus on pulmonary vascular disease

With the advent of anti-retroviral therapy, non-AIDS-related comorbidities have increased in people living with HIV. Among these comorbidities, pulmonary hypertension (PH) is one of the most common causes of morbidity and mortality. Although chronic HIV-1 infection is independently associated with the development of pulmonary arterial hypertension, PH in people living with HIV may also be the outcome of various co-morbidities commonly observed in these individuals including chronic obstructive pulmonary disease, left heart disease and co-infections. In addition, the association of these co-morbidities and other risk factors, such as illicit drug use, can exacerbate the development of pulmonary vascular disease. This review will focus on these complex interactions contributing to PH development and exacerbation in HIV patients. We also examine the interactions of HIV proteins, including Nef, Tat, and gp120 in the pulmonary vasculature and how these proteins alter the endothelial and smooth muscle function by transforming them into susceptible PH phenotype. The review also discusses the available infectious and non-infectious animal models to study HIV-associated PAH, highlighting the advantages and disadvantages of each model, along with their ability to mimic the clinical manifestations of HIV-PAH.

Cocaine potentiates an inflammatory response in C6 astroglia-like cells

Cocaine is a highly addictive drug that mediates its effect through altering dopamine metabolism in the central nervous system (CNS), resulting in a feeling of euphoria. Owing to its high lipophilicity, cocaine easily crosses the blood brain barrier of the CNS and reaches various domains of the brain, where it can trigger cellular damage. Cocaine-induced CNS damage may arise due to increased levels of free radicals and nitric oxide (NO) in immunecompetent astroglial cells. In the present study, the potential ability of cocaine to exacerbate the production of inflammatory products, primarily superoxide free radicals (O₂^-), hydrogen peroxide (H₂O₂) and NO/nitrite (NO₂^-) was examined in rat C6 astroglia-like cells challenged with lipopolysaccharide (LPS), a bacterial endotoxin, and interferon gamma (IFNγ), a pro-inflammatory cytokine. Furthermore, the role of cocaine in increasing the expression of hypoxia inducible factor-1 (HIF-1α) and vascular endothelial growth factor (VEGF) in cells was also determined. First, the viability of the cells was assessed when treated with cocaine (0.5-7 mM) for 24 and 48 h. The results showed that cocaine toxicity was both time and dose-dependent. In subsequent studies, cells were challenged with or without LPS and IFNγ, followed by co-treatment with cocaine (1-4 mM) for 24 h. Cocaine treatment did not increase O₂^- or H₂O₂ production in the challenged or unchallenged cells. Similarly, cocaine treatment did not increase NO/NO₂^- production in the unchallenged cells; however, NO/NO₂^- levels in the challenged cells was increased 40-50-fold upon cocaine treatment compared with the corresponding unchallenged group. The HIF-1α and VEGF levels were significantly increased in the challenged cells at higher cocaine doses compared with the unchallenged cells. Since high concentrations of NO are associated with inflammation, the high levels of NO production observed in the present study suggested that cocaine may have potentiated the inflammatory response in the challenged C6 astroglia-like cells.

HIV X4 Variants Increase Arachidonate 5-Lipoxygenase in the Pulmonary Microenvironment and are associated with Pulmonary Arterial Hypertension

Pulmonary Arterial Hypertension (PAH) is overrepresented in People Living with Human Immunodeficiency Virus (PLWH). HIV protein gp120 plays a key role in the pathogenesis of HIV-PAH. Genetic changes in HIV gp120 determine viral interactions with chemokine receptors; specifically, HIV-X4 viruses interact with CXCR4 while HIV-R5 interact with CCR5 co-receptors. Herein, we leveraged banked samples from patients enrolled in the NIH Lung HIV studies and used bioinformatic analyses to investigate whether signature sequences in HIV-gp120 that predict tropism also predict PAH. Further biological assays were conducted in pulmonary endothelial cells in vitro and in HIV-transgenic rats. We found that significantly more persons living with HIV-PAH harbor HIV-X4 variants. Multiple HIV models showed that recombinant gp120-X4 as well as infectious HIV-X4 remarkably increase arachidonate 5-lipoxygenase (ALOX5) expression. ALOX5 is essential for the production of leukotrienes; we confirmed that leukotriene levels are increased in bronchoalveolar lavage fluid of HIV-infected patients. This is the first report associating HIV-gp120 genotype to a pulmonary disease phenotype, as we uncovered X4 viruses as potential agents in the pathophysiology of HIV-PAH. Altogether, our results allude to the supplementation of antiretroviral therapy with ALOX5 antagonists to rescue patients with HIV-X4 variants from fatal PAH.

NADPH oxidase-mediated endothelial injury in HIV- and opioid-induced pulmonary arterial hypertension

We previously demonstrated that the combined exposure of human pulmonary microvascular endothelial cells (HPMECs) to morphine and viral protein(s) results in the oxidative stress-mediated induction of autophagy, leading to shift in the cells from early apoptotic to apoptosis-resistant proliferative status associated with the angioproliferative remodeling observed in pulmonary arterial hypertension (PAH). In this study, we tried to delineate the major source of HIV-1 protein Tat and morphine induced oxidative burst in HPMECs and its consequences on vascular remodeling and PAH in an in vivo model. We observed switch from the initial increased expression of NADPH oxidase (NOX) 2 in response to acute treatment of morphine and HIV-Tat to later increased expression of NOX4 on chronic treatment in the endoplasmic reticulum of HPMECs without any alterations in the mitochondria. Furthermore, NOX-dependent induction of autophagy was observed to play a pivotal role in regulating the endothelial cell survival. Our in vivo findings showed significant increase in pulmonary vascular remodeling, right ventricular systolic pressure, and Fulton index in HIV-transgenic rats on chronic administration of morphine. This was associated with increased oxidative stress in lung tissues and rat pulmonary microvascular endothelial cells. Additionally, endothelial cells from morphine-treated HIV-transgenic rats demonstrated increased expression of NOX2 and NOX4 proteins, inhibition of which ameliorated their increased survival upon serum starvation. In conclusion, this study describes NADPH oxidases as one of the main players in the oxidative stress-mediated endothelial dysfunction on the dual hit of HIV-viral protein(s) and opioids.

Long Non-coding RNAs Mechanisms of Action in HIV-1 Modulation and the Identification of Novel Therapeutic Targets

This review aims to highlight the role of long non-coding RNAs in mediating human immunodeficiency virus (HIV-1) viral replication, latency, disease susceptibility and progression. In particular, we focus on identifying possible lncRNA targets and their purported mechanisms of action for future drug design or gene therapeutics.

Analysis of lncRNA-miRNA-mRNA Interactions in Hyper-proliferative Human Pulmonary Arterial Smooth Muscle Cells

We previously reported enhanced proliferation of smooth muscle cells on the combined exposure of HIV proteins and cocaine leading to the development of HIV-pulmonary arterial hypertension. Here, we attempt to comprehensively understand the interactions between long noncoding RNAs (lncRNAs), mRNAs and micro-RNAs (miRNAs) to determine their role in smooth muscle hyperplasia. Differential expression of lncRNAs, mRNAs and miRNAs were obtained by microarray and small-RNA sequencing from HPASMCs treated with and without cocaine and/or HIV-Tat. LncRNA to mRNA associations were conjectured by analyzing their genomic proximity and by interrogating their association to vascular diseases and cancer co-expression patterns reported in the relevant databases. Neuro-active ligand receptor signaling, Ras signaling and PI3-Akt pathway were among the top pathways enriched in either differentially expressed mRNAs or mRNAs associated to lncRNAs. HPASMC with combined exposure to cocaine and Tat (C + T) vs control identified the following top lncRNA-mRNA pairs, ENST00000495536-HOXB13, T216482-CBL, ENST00000602736-GDF7, and, TCONS_00020413-RND1. Many of the down-regulated miRNAs in the HPASMCs treated with C + T were found to be anti-proliferative and targets of up-regulated lncRNAs targeting up-regulated mRNAs, including down-regulation of miR-185, -491 and up-regulation of corresponding ENST00000585387. Specific knock down of the selected lncRNAs highlighted the importance of non-coding RNAs in smooth muscle hyperplasia.

Sigma-1 Receptor Antagonist (BD1047) Decreases Cathepsin B Secretion in HIV-Infected Macrophages Exposed to Cocaine

Pathogenesis of HIV-associated neurocognitive disorders (HAND) is mediated through the infiltration of perivascular macrophages into the brain with the secretion of viral, neurotoxic and inflammatory proteins. One of these proteins is cathepsin B (CATB), a lysosomal cysteine protease that induces neuronal apoptosis, and increases in plasma and cerebrospinal fluid from HIV-1 infected patients (Cantres-Rosario et al. AIDS 27(3):347-356, 2013). Cocaine further potentiates CATB neurotoxicity in vitro and in vivo (Zenón et al. J NeuroImmune Pharmacol 9(5):703-715, 2014). Modulation of sigma-1 (Sig1R) by cocaine increases oxidative species, cytokines and other factors that promote lysosomal disruption. However, the role of Sig1R in CATB secretion and HIV-1 replication in macrophages exposed to cocaine is unknown. We hypothesized that pharmacological modulation of Sig1R would alter CATB secretion from HIV-1 infected macrophages in vitro and in vivo. To test our hypothesis, monocyte derived-macrophages (MDM) from HIV-1 seronegative donors were isolated, infected with HIV-1ADA, and pretreated with Sig1R antagonist (BD1047) or Sig1R agonist (PRE-084) prior to cocaine exposure and followed for 3,6,9 and 11 days post-infection (dpi). Experiments in vivo were conducted using the HIV encephalitis mouse model (HIVE) with BD1047 treatments prior to cocaine for 14 days. Results demonstrate that in presence of cocaine, BD1047 decreases CATB secretion at 11 dpi, while PRE-084 did not have an effect. In the mouse model, BD1047 treatment prior to cocaine decreased CATB expression, cleaved caspase-3 an p24 antigen levels, reduced astrocytosis, but did not increase MAP-2 or synaptophysin. Results demonstrate that Sig1R plays a role in the modulation of CATB levels in HIV-1 infected MDM exposed to cocaine in vitro and in vivo. Graphical Abstract ᅟ.

Drug abuse and HIV-related pulmonary hypertension: double hit injury

: Improved survival among HIV-1-infected individuals with the advent of antiretroviral therapy has clearly led to a greater prevalence of noninfectious complications. One of the most devastating sequelae in these individuals is the development of pulmonary arterial hypertension (PAH). Various epidemiological studies suggest worse survival of HIV-PAH patients when compared with other forms of PAH. Given that only a subset and not all HIV-infected individuals develop HIV-PAH, it is suggested that an additional second-hit of genetic or environmental trigger is needed for the development of PAH. In this context, it has been well documented that HIV patients who abuse illicit drugs such as stimulants, opioids, and the like, are more susceptible to develop PAH. In this review, we highlight the studies that support the significance of a double hit of HIV and drug abuse in the incidence of PAH and focus on the research that has been undertaken to unravel the pathobiology and vascular remodeling mechanisms underlying the deleterious synergy between HIV infection and drugs of abuse in orchestrating the development of PAH.

Macrophage-derived extracellular vesicles mediate smooth muscle hyperplasia: role of altered miRNA cargo in response to HIV infection and substance abuse

Our previous studies consistently demonstrate enhanced pulmonary vascular remodeling in HIV–infected intravenous drug users, and in simian immunodeficiency virus–infected macaques or HIV-transgenic rats exposed to opioids or cocaine. Although we reported an associated increase in perivascular inflammation, the exact role of inflammatory cells in the development of pulmonary vascular remodeling remains unknown. In this study, HIV–infected and cocaine (H+C)–treated human monocyte derived macrophages released a higher number of extracellular vesicles (EVs), compared to HIV-infected or uninfected cocaine-treated macrophages, with a significant increase in the particle size range to 100–150 nm. Treatment of primary human pulmonary arterial smooth muscle cells (HPASMCs) with these EVs resulted in a significant increase in smooth muscle proliferation. We also observed a significant increase in the miRNA-130a level in the EVs derived from H+C-treated macrophages that corresponded with the decrease in the expression of phosphatase and tensin homolog and tuberous sclerosis 1 and 2 and activation of PI3K/protein kinase B signaling in HPASMCs on addition of these EVs. Transfection of HPASMCs with antagomir-130a–ameliorated the EV-induced effect. Thus, we conclude that EVs derived from H+C-treated macrophages promote pulmonary smooth muscle proliferation by delivery of its prosurvival miRNA cargo, which may play a crucial role in the development of PAH.—Sharma, H., Chinnappan, M., Agarwal, S., Dalvi, P., Gunewardena, S., O’Brien-Ladner, A., Dhillon, N. K. Macrophage-derived extracellular vesicles mediate smooth muscle hyperplasia: role of altered miRNA cargo in response to HIV infection and substance abuse.

Cocaine Exposure Increases Blood Pressure and Aortic Stiffness via the miR-30c-5p-Malic Enzyme 1-Reactive Oxygen Species Pathway

Cocaine abuse increases the risk of cardiovascular mortality and morbidity; however, the underlying molecular mechanisms remain elusive. By using a mouse model for cocaine abuse/use, we found that repeated cocaine injection led to increased blood pressure and aortic stiffness in mice associated with elevated levels of reactive oxygen species (ROS) in the aortas, a phenomenon similar to that observed in hypertensive humans. This ROS elevation was correlated with downregulation of Me1 (malic enzyme 1), an important redox molecule that counteracts ROS generation, and upregulation of microRNA (miR)-30c-5p that targets Me1 expression by directly binding to its 3'UTR (untranslated region). Remarkably, lentivirus-mediated overexpression of miR-30c-5p in aortic smooth muscle cells recapitulated the effect of cocaine on Me1 suppression, which in turn led to ROS elevation. Moreover, in vivo silencing of miR-30c-5p in smooth muscle cells resulted in Me1 upregulation, ROS reduction, and significantly suppressed cocaine-induced increases in blood pressure and aortic stiffness-a similar effect to that produced by treatment with the antioxidant N-acetyl cysteine. Discovery of this novel cocaine-↑miR-30c-5p-↓Me1-↑ROS pathway provides a potential new therapeutic avenue for treatment of cocaine abuse-related cardiovascular disease.

Network of MicroRNAs Mediate Translational Repression of Bone Morphogenetic Protein Receptor-2: Involvement in HIV-Associated Pulmonary Vascular Remodeling

BACKGROUND

Earlier, we reported that the simultaneous exposure of pulmonary arterial smooth muscle cells to HIV proteins and cocaine results in the attenuation of antiproliferative bone morphogenetic protein receptor-2 (BMPR2) protein expression without any decrease in its mRNA levels. Therefore, in this study, we aimed to investigate the micro RNA-mediated posttranscriptional regulation of BMPR2 expression.

METHODS AND RESULTS

We identified a network of BMPR2 targeting micro RNAs including miR-216a to be upregulated in response to cocaine and Tat-mediated augmentation of oxidative stress and transforming growth factor-β signaling in human pulmonary arterial smooth muscle cells. By using a loss or gain of function studies, we observed that these upregulated micro RNAs are involved in the Tat- and cocaine-mediated smooth muscle hyperplasia via regulation of BMPR2 protein expression. These in vitro findings were further corroborated using rat pulmonary arterial smooth muscle cells isolated from HIV transgenic rats exposed to cocaine. More importantly, luciferase reporter and in vitro translation assays demonstrated that direct binding of novel miR-216a and miR-301a to 3'UTR of BMPR2 results in the translational repression of BMPR2 without any degradation of its mRNA.

CONCLUSIONS

We identified for the first time miR-216a as a negative modulator of BMPR2 translation and observed it to be involved in HIV protein(s) and cocaine-mediated enhanced proliferation of pulmonary smooth muscle cells.

Pulmonary disease in HIV-infected adults in the era of antiretroviral therapy

: HIV in the antiretroviral therapy era is characterized by multimorbidity and the frequent occurrence of HIV-associated non-AIDS chronic health conditions. Respiratory symptoms and chronic pulmonary diseases, including chronic obstructive pulmonary disease, asthma, and cardiopulmonary dysfunction, are among the conditions that may present in persons living with HIV. Tobacco smoking, which is disproportionately high among persons living HIV, strongly contributes to the risk of pulmonary disease. Additionally, features associated with and at times unique to HIV, including persistent inflammation, immune cell activation, oxidative stress, and dysbiosis, may also contribute. This review summarizes the available literature regarding epidemiology of and risk factors for respiratory symptoms and chronic pulmonary disease in the current era.

Dasatinib increases endothelial permeability leading to pleural effusion

Pleural effusion is a frequent side-effect of dasatinib, a second-generation tyrosine kinase inhibitor used in the treatment of chronic myelogenous leukaemia. However, the underlying mechanisms remain unknown. We hypothesised that dasatinib alters endothelial integrity, resulting in increased pulmonary vascular endothelial permeability and pleural effusion.To test this, we established the first animal model of dasatinib-related pleural effusion, by treating rats with a daily regimen of high doses of dasatinib (10 mg·kg^-1·day^-1 for 8 weeks).Pleural ultrasonography revealed that rats chronically treated with dasatinib developed pleural effusion after 5 weeks. Consistent with these in vivo observations, dasatinib led to a rapid and reversible increase in paracellular permeability of human pulmonary endothelial cell monolayers as reflected by increased macromolecule passage, loss of vascular endothelial cadherin and zonula occludens-1 from cell-cell junctions, and the development of actin stress fibres. These results were replicated using human umbilical vein endothelial cells and confirmed by decreased endothelial resistance. Interestingly, we demonstrated that this increased endothelial permeability is a reactive oxygen species (ROS)-dependent mechanism in vitro and in vivo using a cotreatment with an antioxidant agent, N-acetylcysteine.This study shows that dasatinib alters pulmonary endothelial permeability in a ROS-dependent manner in vitro and in vivo leading to pleural effusion.

Drug Use is Associated with Anti-CD4 IgG-mediated CD4+ T Cell Death and Poor CD4+ T Cell Recovery in Viral-suppressive HIV-infected Individuals Under Antiretroviral Therapy

BACKGROUND

The role and mechanism of drug use or abuse in Antiretroviral Therapy (ART)-treated HIV disease are not completely known.

METHODS

To investigate the impact of drug use on HIV pathogenesis without confounding by HIV replication and ART adherence, we first analyzed the data from our clinical database in 103 HIV+ subjects with viral-suppressed ART treatment by a multiple regression test.

RESULTS

We found that HIV+ drug users had lower CD4+ T cell counts but higher CD8+ T cell counts compared to HIV+ non-drug users, and both drug use and nadir CD4+ T cell counts was independently associated with CD4+ T cell recovery after controlling for sex and age. Next, we enrolled individuals from four study groups, HIV-negative and HIV+ subjects without any substance use, HIV-negative and HIV+ subjects with current illicit drug use (either non-injection cocaine or cannabis). All HIV+ subjects were viral-suppressed with ART treatment (≥ 2 years). Notably, HIV+ drug users had increased plasma anti-CD4 IgG levels compared to the other three study groups which were inversely correlated with decreased CD4+ T cell counts only in HIV+ drug users. There was a significant increase in CD4+ T cell recovery following ART in HIV+ non-drug users but not in HIV+ drug users. Anti-CD4 IgGs purified from plasma of HIV+ drug users induced CD4+ T cell death in vitro through Antibody-Dependent Cytotoxicity (ADCC).

CONCLUSION

These results suggest that drug use prevents immune reconstitution in HIV-infected individuals despite long-term ART treatment and viral suppression.

Lung Vascular Remodeling, Cardiac Hypertrophy, and Inflammatory Cytokines in SHIVnef-Infected Macaques

Fatal pulmonary arterial hypertension (PAH) affects HIV-infected individuals at significantly higher frequencies. We previously showed plexiform-like lesions characterized by recanalized lumenal obliteration, intimal disruption, medial hypertrophy, and thrombosis consistent with PAH in rhesus macaques infected with chimeric SHIVnef but not with the parental SIVmac239, suggesting that Nef is implicated in the pathophysiology of HIV-PAH. However, the current literature on non-human primates as animal models for SIV(HIV)-associated pulmonary disease reports the ultimate pathogenic pulmonary outcomes of the research efforts; however, the variability and features in the actual disease progression remain poorly described, particularly when using different viral sources for infection. We analyzed lung histopathology, performed immunophenotyping of cells in plexogenic lesions pathognomonic of PAH, and measured cardiac hypertrophy biomarkers and cytokine expression in plasma and lung of juvenile SHIVnef-infected macaques. Here, we report significant hematopathologies, changes in cardiac biomarkers consistent with ventricular hypertrophy, significantly increased levels of interleukin-12 and GM-CSF and significantly decreased sCD40 L, CCL-2, and CXCL-1 in plasma of the SHIVnef group. Pathway analysis of inflammatory gene expression predicted activation of NF-κB transcription factor RelB and inhibition of bone morphogenetic protein type-2 in the setting of SHIVnef infection. Our findings highlight the utility of SHIVnef-infected macaques as suitable models of HIV-associated pulmonary vascular remodeling as pathogenetic changes are concordant with features of idiopathic, familial, scleroderma, and HIV-PAH.

Non-infectious Pulmonary Diseases and HIV

Pulmonary complications remain among the most frequent causes of morbidity and mortality for individuals with HIV despite the advent of antiretroviral therapy (ART) and improvement in its efficacy and availability. The prevalence of non-infectious pulmonary diseases is rising in this population, reflecting both an increase in smoking and the independent risk associated with HIV. The unique mechanisms of pulmonary disease in these patients remain poorly understood, and direct effects of HIV, genetic predisposition, inflammatory pathways, and co-infections have all been implicated. Lung cancer, chronic obstructive pulmonary disease (COPD), and pulmonary hypertension are the most prevalent non-infectious pulmonary diseases in persons with HIV, and the risk of each of these diseases is higher among HIV-infected (HIV+) persons than in the general population. This review discusses the latest advances in the literature on these important complications of HIV infection.

An atypical subacute presentation of posterior reversible encephalopathy syndrome

Posterior reversible encephalopathy syndrome (PRES) characteristically presents with rapid onset of headache, seizure, encephalopathy, and visual changes, along with evidence of parieto-occipital vasogenic edema on magnetic resonance imaging. We describe the case of a 41-year-old female with a protracted presentation of two of the four classic PRES symptoms, which were not immediately recognized as PRES due to the presence of multiple other comorbidities and reasons for encephalopathy. This case highlights the possibility of atypical presentations of PRES and the diagnostic challenges in making this clinical diagnosis when competing diagnoses are present.

Hyperactive TGF-β Signaling in Smooth Muscle Cells Exposed to HIV-protein(s) and Cocaine: Role in Pulmonary Vasculopathy

We earlier demonstrated synergistic increase in the proliferation of pulmonary smooth muscle cells on exposure to HIV-proteins and/or cocaine due to severe down-modulation of bone morphogenetic protein receptor (BMPR) axis: the anti-proliferative arm of TGF-β super family of receptors. Here, now we demonstrate the effect of HIV-Tat and cocaine on the proliferative TGF-β signaling cascade. We observed a significant increase in the secretion of TGF-β1 ligand along with enhanced protein expression of TGFβ Receptor (TGFβR)-1, TGFβR-2 and phosphorylated SMAD2/3 in human pulmonary arterial smooth muscle cells on treatment with cocaine and Tat. Further, we noticed an increase in the levels of p-TAK1 complexed with TGFβR-2. Concomitant to this a significant increase in the activation of TAK1-mediated, SMAD-independent downstream signaling molecules: p-MKK4 and p-JNK was observed. However, activation of MKK3/6-p38MAPK, another axis downstream of TAK1 was found to be reduced due to attenuation in the protein levels of BMPR2. Both SMAD and non-SMAD dependent TGFβR cascades were found to contribute to hyper-proliferation. Finally the increase in the levels of phosphorylated TGFβR1 and TGFβR2 on exposure to HIV-proteins and cocaine was confirmed in pulmonary smooth muscle cells from cocaine injected HIV-transgenic rats and in total lung extracts from HIV infected cocaine and/or opioid users.

Reactive Oxygen Species/Hypoxia-Inducible Factor-1α/Platelet-Derived Growth Factor-BB Autocrine Loop Contributes to Cocaine-Mediated Alveolar Epithelial Barrier Damage

Abuse of psychostimulants, such as cocaine, has been shown to be closely associated with complications of the lung, such as pulmonary hypertension, edema, increased inflammation, and infection. However, the mechanism by which cocaine mediates impairment of alveolar epithelial barrier integrity that underlies various pulmonary complications has not been well determined. Herein, we investigate the role of cocaine in disrupting the alveolar epithelial barrier function and the associated signaling cascade. Using the combinatorial electric cell-substrate impedance sensing and FITC-dextran permeability assays, we demonstrated cocaine-mediated disruption of the alveolar epithelial barrier, as evidenced by increased epithelial monolayer permeability with a concomitant loss of the tight junction protein zonula occludens-1 (Zo-1) in both mouse primary alveolar epithelial cells and the alveolar epithelial cell line, L2 cells. To dissect the signaling pathways involved in this process, we demonstrated that cocaine-mediated induction of permeability factors, platelet-derived growth factor (PDGF-BB) and vascular endothelial growth factor, involved reactive oxygen species (ROS)-dependent induction of hypoxia-inducible factor (HIF)-1α. Interestingly, we demonstrated that ROS-dependent induction of another transcription factor, nuclear factor erythroid-2-related factor-2, that did not play a role in cocaine-mediated barrier dysfunction. Importantly, this study identifies, for the first time, that ROS/HIF-1α/PDGF-BB autocrine loop contributes to cocaine-mediated barrier disruption via amplification of oxidative stress and downstream signaling. Corroboration of these cell culture findings in vivo demonstrated increased permeability of the alveolar epithelial barrier, loss of expression of Zo-1, and a concomitantly increased expression of both HIF-1α and PDGF-BB. Pharmacological blocking of HIF-1α significantly abrogated cocaine-mediated loss of Zo-1. Understanding the mechanism(s) by which cocaine mediates barrier dysfunction could provide insights into the development of potential therapeutic targets for cocaine-mediated pulmonary hypertension.

HIV-1 Transactivator Protein Induces ZO-1 and Neprilysin Dysfunction in Brain Endothelial Cells via the Ras Signaling Pathway

Amyloid beta (Aβ) deposition is increased in human immunodeficiency virus-1- (HIV-1-) infected brain, but the mechanisms are not fully understood. The aim of the present study was to evaluate the role of Ras signaling in HIV-1 transactivator protein- (Tat-) induced Aβ accumulation in human cerebral microvascular endothelial cells (HBEC-5i). Cell viability assay showed that 1 μg/mL Tat and 20 μmol/L of the Ras inhibitor farnesylthiosalicylic acid (FTS) had no significant effect on HBEC-5i cell viability after 24 h exposure. Exposure to Tat decreased protein and mRNA levels of zonula occludens- (ZO-) 1 and Aβ-degrading enzyme neprilysin (NEP) in HBEC-5i cells as determined by western blotting and quantitative real-time polymerase chain reaction. Exposure to Tat also increased transendothelial transfer of Aβ and intracellular reactive oxygen species (ROS) levels; however, these effects were attenuated by FTS. Collectively, these results suggest that the Ras signaling pathway is involved in HIV-1 Tat-induced changes in ZO-1 and NEP, as well as Aβ deposition in HBEC-5i cells. FTS partially protects blood-brain barrier (BBB) integrity and inhibits Aβ accumulation.

Neoatherosclerosis after Drug-Eluting Stent Implantation: Roles and Mechanisms

In-stent neoatherosclerosis (NA), characterized by a relatively thin fibrous cap and large volume of yellow-lipid accumulation after drug-eluting stents (DES) implantation, has attracted much attention owing to its close relationship with late complications, such as revascularization and late stent thrombosis (ST). Accumulating evidence has demonstrated that more than one-third of patients with first-generation DES present with NA. Even in the advent of second-generation DES, NA still occurs. It is indicated that endothelial dysfunction induced by DES plays a critical role in neoatherosclerotic development. Upregulation of reactive oxygen species (ROS) induced by DES implantation significantly affects endothelial cells healing and functioning, therefore rendering NA formation. In light of the role of ROS in suppression of endothelial healing, combining antioxidant therapies with stenting technology may facilitate reestablishing a functioning endothelium to improve clinical outcome for patients with stenting.

Maintaining lung health with longstanding HIV

PURPOSE OF REVIEW

Human immunodeficiency virus (HIV) is now managed as a chronic disease. Non-infectious pulmonary conditions have replaced infection as the biggest threat to lung health, particularly as HIV cohorts age, but there is no consensus on how best to maintain long-term lung health. We review the epidemiology and pathogenesis of chronic obstructive pulmonary disease (COPD), pulmonary arterial hypertension (PAH), and lung cancer in HIV-seropositive individuals.

RECENT FINDINGS

Diagnoses of COPD are now up to 50% more prevalent in HIV-seropositive individuals than HIV-uninfected controls, and prospective pulmonary function studies find significant impairment in 7% to more than 50% of HIV-seropositive individuals. The prevalence of HIV-PAH is 0.2-0.5%, and lung cancer is two to three times more prevalent in HIV-seropositive individuals. Although host factors such as age and smoking have a role, HIV is an independent contributor to the pathogenesis of COPD, PAH, and lung cancer. Chronic inflammation, immune senescence, oxidative stress, and direct effects of viral proteins are all potential pathogenetic mechanisms. Despite their prevalence, non-infectious lung diseases remain underrecognized and evidence for effective screening strategies in HIV-seropositive individuals is limited.

SUMMARY

COPD, PAH, and lung cancer are a growing threat to lung health in the highly active antiretroviral therapy era necessitating early recognition.

Cocaine-mediated microglial activation involves the ER stress-autophagy axis

Cocaine abuse leads to neuroinflammation, which, in turn, contributes to the pathogenesis of neurodegeneration associated with advanced HIV-1 infection. Autophagy plays important roles in both innate and adaptive immune responses. However, the possible functional link between cocaine and autophagy has not been explored before. Herein, we demonstrate that cocaine exposure induced autophagy in both BV-2 and primary rat microglial cells as demonstrated by a dose- and time-dependent induction of autophagy-signature proteins such as BECN1/Beclin 1, ATG5, and MAP1LC3B. These findings were validated wherein cocaine treatment of BV-2 cells resulted in increased formation of puncta in cells expressing either endogenous MAP1LC3B or overexpressing GFP-MAP1LC3B. Specificity of cocaine-induced autophagy was confirmed by treating cells with inhibitors of autophagy (3-MA and wortmannin). Intriguingly, cocaine-mediated induction of autophagy involved upstream activation of 2 ER stress pathways (EIF2AK3- and ERN1-dependent), as evidenced by the ability of the ER stress inhibitor salubrinal to ameliorate cocaine-induced autophagy. In vivo validation of these findings demonstrated increased expression of BECN1, ATG5, and MAP1LC3B-II proteins in cocaine-treated mouse brains compared to untreated animals. Increased autophagy contributes to cocaine-mediated activation of microglia since pretreatment of cells with wortmannin resulted in decreased expression and release of inflammatory factors (TNF, IL1B, IL6, and CCL2) in microglial cells. Taken together, our findings suggest that cocaine exposure results in induction of autophagy that is closely linked with neuroinflammation. Targeting autophagic proteins could thus be considered as a therapeutic strategy for the treatment of cocaine-related neuroinflammation diseases.

The neurobiology of HIV and its impact on cognitive reserve: A review of cognitive interventions for an aging population

The medications used to treat HIV have reduced the severity of cognitive deficits; yet, nearly half of adults with HIV still exhibit some degree of cognitive deficits, referred to as HIV-associated neurocognitive disorder or HAND. These cognitive deficits interfere with everyday functioning such as emotional regulation, medication adherence, instrumental activities of daily living, and even driving a vehicle. As adults are expected to live a normal lifespan, the process of aging in this clinical population may exacerbate such cognitive deficits. Therefore, it is important to understand the neurobiological mechanisms of HIV on cognitive reserve and develop interventions that are either neuroprotective or compensate for such cognitive deficits. Within the context of cognitive reserve, this article delivers a state of the science perspective on the causes of HAND and provides possible interventions for addressing such cognitive deficits. Suggestions for future research are also provided.

Cardiovascular and Hepatic Toxicity of Cocaine: Potential Beneficial Effects of Modulators of Oxidative Stress

Oxidative stress (OS) is thought to play an important role in the pharmacological and toxic effects of various drugs of abuse. Herein we review the literature on the mechanisms responsible for the cardiovascular and hepatic toxicity of cocaine with special focus on OS-related mechanisms. We also review the preclinical and clinical literature concerning the putative therapeutic effects of OS modulators (such as N-acetylcysteine, superoxide dismutase mimetics, nitroxides and nitrones, NADPH oxidase inhibitors, xanthine oxidase inhibitors, and mitochondriotropic antioxidants) for the treatment of cocaine toxicity. We conclude that available OS modulators do not appear to have clinical efficacy.

Ligand-Independent Activation of Platelet-Derived Growth Factor Receptor β during Human Immunodeficiency Virus-Transactivator of Transcription and Cocaine-Mediated Smooth Muscle Hyperplasia

Our previous study supports an additive effect of cocaine to human immunodeficiency virus infection in the development of pulmonary arteriopathy through enhancement of proliferation of pulmonary smooth muscle cells (SMCs), while also suggesting involvement of platelet-derived growth factor receptor (PDGFR) activation in the absence of further increase in PDGF-BB ligand. Redox-related signaling pathways have been shown to regulate tyrosine kinase receptors independent of ligand binding, so we hypothesized that simultaneous treatment of SMCs with transactivator of transcription (Tat) and cocaine may be able to indirectly activate PDGFR through modulation of reactive oxygen species (ROS) without the need for PDGF binding. We found that blocking the binding of ligand using suramin or monoclonal IMC-3G3 antibody significantly reduced ligand-induced autophosphorylation of Y1009 without affecting ligand-independent transphosphorylation of Y934 residue on PDGFRβ in human pulmonary arterial SMCs treated with both cocaine and Tat. Combined treatment of human pulmonary arterial SMCs with cocaine and Tat resulted in augmented production of superoxide radicals and hydrogen peroxide when compared with either treatment alone. Inhibition of this ROS generation prevented cocaine- and Tat-mediated Src activation and transphosphorylation of PDGFRβ at Y934 without any changes in phosphorylation of Y1009, in addition to attenuation of smooth muscle hyperplasia. Furthermore, pretreatment with an Src inhibitor, PP2, also suppressed cocaine- and Tat-mediated enhanced Y934 phosphorylation and smooth muscle proliferation. Finally, we report total abrogation of cocaine- and Tat-mediated synergistic increase in cell proliferation on inhibition of both ligand-dependent and ROS/Src-mediated ligand-independent phosphorylation of PDGFRβ.

Cocaine enhances HIV-1 gp120-induced lymphatic endothelial dysfunction in the lung

Pulmonary complications are common in both AIDS patients and cocaine users. We addressed the cellular and molecular mechanisms by which HIV and cocaine may partner to induce their deleterious effects. Using primary lung lymphatic endothelial cells (L-LECs), we examined how cocaine and HIV-1 gp120, alone and together, modulate signaling and functional properties of L-LECs. We found that brief cocaine exposure activated paxillin and induced cytoskeletal rearrangement, while sustained exposure increased fibronectin (FN) expression, decreased Robo4 expression, and enhanced the permeability of L-LEC monolayers. Moreover, incubating L-LECs with both cocaine and HIV-1 gp120 exacerbated hyperpermeability, significantly enhanced apoptosis, and further impaired in vitro wound healing as compared with cocaine alone. Our studies also suggested that the sigma-1 receptor (Sigma-1R) and the dopamine-4 receptor (D4R) are involved in cocaine-induced pathology in L-LECs. Seeking clinical correlation, we found that FN levels in sera and lung tissue of HIV(+) donors were significantly elevated as compared to HIV(-) donors. Our in vitro data demonstrate that cocaine and HIV-1 gp120 induce dysfunction and damage of lung lymphatics, and suggest that cocaine use may exacerbate pulmonary edema and fibrosis associated with HIV infection. Continued exploration of the interplay between cocaine and HIV should assist the design of therapeutics to ameliorate HIV-induced pulmonary disorders within the drug using population.

DJ1 expression downregulates in neuroblastoma cells (SK-N-MC) chronically exposed to HIV-1 and cocaine

Background: HIV-associated neurological disorder (HAND) has long been recognized as a consequence of human immunodeficiency virus (HIV) infection in the brain. The pathology of HAND gets more complicated with the recreational drug use such as cocaine. Recent studies have suggested multiple genetic influences involved in the pathology of addiction and HAND but only a fraction of the entire genetic risk has been investigated so far. In this regard, role of DJ1 protein (a gene linked to autosomal recessive early-onset Parkinson’s disease) in regulating dopamine (DA) transmission and reactive oxygen species (ROS) production in neuronal cells will be worth investigating in HIV-1 and cocaine exposed microenvironment. Being a very abundant protein in the brain, DJ1 could serve as a potential marker for early detection of HIV-1 and/or cocaine related neurological disorder.

Methods:In vitro analysis was done to observe the effect of HIV-1 and/or cocaine on DJ1 protein expression in neuroblastoma cells (SK-N-MC). Gene and protein expression analysis of DJ1 was done on the HIV infected and/or cocaine treated SK-N-MC and compared to untreated cells using real time PCR, Western Blot and flow cytometry. Effect of DJ1 dysregulation on oxidative stress was analyzed by measuring ROS production in these cells.

Results: Gene expression and protein analysis indicated that there was a significant decrease in DJ1 expression in SK-N-MC chronically exposed to HIV-1 and/or cocaine which is inversely proportional to ROS production.

Conclusion: This is the first study to establish that DJ1 expression level in the neuronal cells significantly decreased in presence of HIV-1 and/or cocaine indicating oxidative stress level of DA neurons.

Infections in the immunosuppressed host

The interaction between host immunity and infections in the context of a suppressed immune system presents an opportunity to study the interaction of colonization and infection with the development of acute and chronic pulmonary morbidity and mortality. This article summarizes presentations at the Pittsburgh International Lung Conference about comorbid consequences in two categories of immunosuppressed hosts: HIV-infected individuals and lung transplant recipients. Specifically, chronic obstructive pulmonary disease, pulmonary hypertension, and chronic lung rejection after transplant are three diseases that may be consequences of colonization or infection by viruses or fungi, whether HIV itself or the opportunistic infections Pneumocystis and cytomegalovirus. In the fourth section, we discuss unique aspects of infections after lung transplant as well as the battle against multidrug-resistant organisms in this population and theorize that the immunosuppressed population may provide a unique group of patients in which to study ways to overcome nosocomial pathogenic challenges. These host-pathogen interactions serve as models for developing new strategies to reduce acute and chronic morbidity due to colonization and subclinical infection, and potential therapeutic avenues, which are often overlooked in the clinical arena.

HIV-associated pulmonary arterial hypertension: from bedside to the future

Pulmonary arterial hypertension (PAH) is a life-threatening complication of HIV infection. The prevalence of HIV-associated PAH (HIV-PAH) seems not to be changed over time, regardless of the introduction of highly active antiretroviral therapy (HAART). In comparison with the incidence of idiopathic PAH in the general population (1-2 per million), HIV-infected patients have a 2500-fold increased risk of developing PAH. HIV-PAH treatment is similar to that for all PAH conditions and includes lifestyle changes, general treatments and specific treatments.

HIV-1 Tat alters neuronal autophagy by modulating autophagosome fusion to the lysosome: implications for HIV-associated neurocognitive disorders

Antiretroviral therapy has increased the life span of HIV+ individuals; however, HIV-associated neurocognitive disorder (HAND) occurrence is increasing in aging HIV patients. Previous studies suggest HIV infection alters autophagy function in the aging CNS and HIV-1 proteins affect autophagy in monocyte-derived cells. Despite these findings, the mechanisms leading to dysregulated autophagy in the CNS remain unclear. Here we sought to determine how HIV Tat dysregulates autophagy in neurons. Tat caused a dose-dependent decrease in autophagosome markers, microtubule-associated protein-1 light chain β II (LC3II), and sequestosome 1(SQSTM1), in a membrane-enriched fraction, suggesting Tat increases autophagic degradation. Bafilomycin A1 increased autophagosome number, LC3II, and SQSTM1 accumulation; Tat cotreatment diminished this effect. Tat had no effect when 3-methyladenine or knockdown of beclin 1 blocked early stages of autophagy. Tat increased numbers of LC3 puncta and resulted in the formation of abnormal autophagosomes in vitro. Likewise, in vivo studies in GFAP-Tat tg mice showed increased autophagosome accumulation in neurons, altered LC3II levels, and neurodegeneration. These effects were reversed by rapamycin treatment. Tat colocalized with autophagosome and lysosomal markers and enhanced the colocalization of autophagosome with lysosome markers. Furthermore, co-IP studies showed that Tat interacts with lysosomal-associated membrane protein 2A (LAMP2A) in vitro and in vivo, and LAMP2A overexpression reduces Tat-induced neurotoxicity. Hence, Tat protein may induce autophagosome and lysosome fusion through interaction with LAMP2A leading to abnormal neuronal autophagy function and dysregulated degradation of critical intracellular components. Therapies targeting Tat-mediated autophagy alterations may decrease neurodegeneration in aging patients with HAND.

Cocaine potentiates cathepsin B secretion and neuronal apoptosis from HIV-infected macrophages

Substance abuse is a risk factor for HIV infection and progression to AIDS. Recent evidence establishes that cocaine use promotes brain perivascular macrophage infiltration and microglia activation. The lysosomal protease cathepsin B is increased in monocytes from patients with HIV dementia and its secretion induces 10-15% of neurotoxicity. Here we asked if cocaine potentiates cathepsin B secretion from HIV-infected monocyte-derived macrophages (MDM) and its effect in neuronal apoptosis. Samples of plasma, CSF, and post-mortem brain tissue from HIV positive patients that used cocaine were tested for cathepsin B and its inhibitors to determine the in vivo relevance of these findings. MDM were inoculated with HIV-1ADA, exposed to cocaine, and the levels of secreted and bioactive cathepsin B and its inhibitors were measured at different time-points. Cathepsin B expression (p < 0.001) and activity (p < 0.05) increased in supernatants from HIV-infected cocaine treated MDM compared with HIV-infected cocaine negative controls. Increased levels of cystatin B expression was also found in supernatants from HIV-cocaine treated MDM (p < 0.05). A significant increase in 30% of apoptotic neurons was obtained that decreased to 5% with the specific cathepsin B inhibitor (CA-074) or with cathepsin B antibody. Cathepsin B was significantly increased in the plasma and post-mortem brain tissue of HIV/cocaine users over non-drug users. Our results demonstrated that cocaine potentiates cathepsin B secretion in HIV-infected MDM and increase neuronal apoptosis. These findings provide new evidence that cocaine synergize with HIV-1 infection in increasing cathepsin B secretion and neurotoxicity.