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Hong S, Banks WA. Role of the immune system in HIV-associated neuroinflammation and neurocognitive implications. Brain Behav Immun 2015; 45:1-12. [PMID: 25449672 PMCID: PMC4342286 DOI: 10.1016/j.bbi.2014.10.008] [Citation(s) in RCA: 250] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 12/16/2022] Open
Abstract
Individuals living with HIV who are optimally treated with combination antiretroviral therapy (cART) can now lead an extended life. In spite of this remarkable survival benefit from viral suppression achieved by cART in peripheral blood, the rate of mild to moderate cognitive impairment remains high. A cognitive decline that includes impairments in attention, learning and executive function is accompanied by increased rates of mood disorders that together adversely impact the daily life of those with chronic HIV infection. The evidence is clear that cells in the brain are infected with HIV that has crossed the blood-brain barrier both as cell-free virus and within infected monocytes and T cells. Viral proteins that circulate in blood can induce brain endothelial cells to release cytokines, invoking another source of neuroinflammation. The difficulty of efficient delivery of cART to the central nervous system (CNS) contributes to elevated viral load in the CNS, resulting in a persistent HIV-associated neurocognitive disorders (HAND). The pathogenesis of HAND is multifaceted, and mounting evidence indicates that immune cells play a major role. HIV-infected monocytes and T cells not only infect brain resident cells upon migration into the CNS but also produce proinflammatory cytokines such as TNF and IL-1ß, which in turn, further activate microglia and astrocytes. These activated brain resident cells, along with perivascular macrophages, are the main contributors to neuroinflammation in HIV infection and release neurotoxic factors such as excitatory amino acids and inflammatory mediators, resulting in neuronal dysfunction and death. Cytokines, which are elevated in the blood of patients with HIV infection, may also contribute to brain inflammation by entering the brain from the blood. Host factors such as aging and co-morbid conditions such as cytomegalovirus co-infection and vascular pathology are important factors that affect the HIV-host immune interactions in HAND pathogenesis. By these diverse mechanisms, HIV-1 induces a neuroinflammatory response that is likely to be a major contributor to the cognitive and behavior changes seen in HIV infection.
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Affiliation(s)
- Suzi Hong
- Department of Psychiatry, University of California San Diego, United States.
| | - William A. Banks
- Geriatric Research Clinical and Education Center, Veterans Affairs Puget Sound Health Care System and Division of Gerontology and Geriatric Medicine, Department of Medicine, University of Washington School of Medicine
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Mikitsh JL, Chacko AM. Pathways for small molecule delivery to the central nervous system across the blood-brain barrier. PERSPECTIVES IN MEDICINAL CHEMISTRY 2014; 6:11-24. [PMID: 24963272 PMCID: PMC4064947 DOI: 10.4137/pmc.s13384] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 04/29/2014] [Accepted: 04/29/2014] [Indexed: 01/04/2023]
Abstract
The treatment of central nervous system (CNS) disease has long been difficult due to the ineffectiveness of drug delivery across the blood-brain barrier (BBB). This review summarizes important concepts of the BBB in normal versus pathophysiology and how this physical, enzymatic, and efflux barrier provides necessary protection to the CNS during drug delivery, and consequently treatment challenging. Small molecules account for the vast majority of available CNS drugs primarily due to their ability to penetrate the phospholipid membrane of the BBB by passive or carrier-mediated mechanisms. Physiochemical and biological factors relevant for designing small molecules with optimal capabilities for BBB permeability are discussed, as well as the most promising classes of transporters suitable for small-molecule drug delivery. Clinically translatable imaging methodologies for detecting and quantifying drug uptake and targeting in the brain are discussed as a means of further understanding and refining delivery parameters for both drugs and imaging probes in preclinical and clinical domains. This information can be used as a guide to design drugs with preserved drug action and better delivery profiles for improved treatment outcomes over existing therapeutic approaches.
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Affiliation(s)
- John L Mikitsh
- Department of Radiology, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Ann-Marie Chacko
- Department of Radiology, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
- Center for Targeted Therapeutics and Translational Nanomedicine, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Ashraf T, Jiang W, Hoque MT, Henderson J, Wu C, Bendayan R. Role of anti-inflammatory compounds in human immunodeficiency virus-1 glycoprotein120-mediated brain inflammation. J Neuroinflammation 2014; 11:91. [PMID: 24884548 PMCID: PMC4046047 DOI: 10.1186/1742-2094-11-91] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2014] [Accepted: 04/15/2014] [Indexed: 11/16/2022] Open
Abstract
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.
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Affiliation(s)
- Tamima Ashraf
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Room 1001, Toronto, ON M5S 3 M2, Canada
| | - Wenlei Jiang
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Room 1001, Toronto, ON M5S 3 M2, Canada
| | - Md Tozammel Hoque
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Room 1001, Toronto, ON M5S 3 M2, Canada
| | - Jeffrey Henderson
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Room 1001, Toronto, ON M5S 3 M2, Canada
| | - Chiping Wu
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Room 1001, Toronto, ON M5S 3 M2, Canada
| | - Reina Bendayan
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Room 1001, Toronto, ON M5S 3 M2, Canada
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Robillard KR, Hoque MT, Bendayan R. Expression of ATP-binding cassette membrane transporters in a HIV-1 transgenic rat model. Biochem Biophys Res Commun 2014; 444:531-6. [DOI: 10.1016/j.bbrc.2014.01.092] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 01/20/2014] [Indexed: 01/09/2023]
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Cressman AM, Petrovic V, Piquette-Miller M. Inflammation-mediated changes in drug transporter expression/activity: implications for therapeutic drug response. Expert Rev Clin Pharmacol 2014; 5:69-89. [DOI: 10.1586/ecp.11.66] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Functional Expression of Drug Transporters in Glial Cells. PHARMACOLOGY OF THE BLOOD BRAIN BARRIER: TARGETING CNS DISORDERS 2014; 71:45-111. [DOI: 10.1016/bs.apha.2014.06.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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De Rosa MF, Robillard KR, Kim CJ, Hoque MT, Kandel G, Kovacs C, Kaul R, Bendayan R. Expression of membrane drug efflux transporters in the sigmoid colon of HIV-infected and uninfected men. J Clin Pharmacol 2013; 53:934-45. [PMID: 23856938 DOI: 10.1002/jcph.132] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Accepted: 06/10/2013] [Indexed: 01/27/2023]
Abstract
The use of antiretroviral therapy (ART) as pre-exposure prophylaxis (PrEP) has gained global attention as a promising HIV prevention strategy in men who have sex with men. Permeability of these agents in the rectal mucosa may be partially regulated by interactions with drug efflux transporters, P-glycoprotein (P-gp), multidrug resistance-associated proteins (MRPs) and/or breast cancer resistance protein (BCRP). The objective of this work was to investigate the expression of drug efflux transporters in recto-sigmoid colon tissues of HIV-infected and uninfected men, and evaluate the association of ART and/or HIV infection with drug transporter expression. MDR1/P-gp, MRPs (1-4) and BCRP mRNA and protein expression were detected in sigmoid colon biopsies of HIV-uninfected individuals. Biopsies from HIV-infected, ART-naïve participants revealed a significant downregulation of P-gp and MRP2 protein levels compared to HIV-uninfected individuals. Biopsies from HIV-infected ART-treated patients showed 1.9-fold higher P-gp protein expression and 1.5-fold higher MRP2 protein expression compared to the ones obtained from the HIV-infected ART-naïve patients. This is a first report demonstrating that HIV infection or ART could alter expression of drug efflux transporters in gut mucosa which in turn could affect the permeability of PrEP antiretroviral agents across this barrier, a highly vulnerable site of HIV transmission.
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Gandhi A, Moorthy B, Ghose R. Drug disposition in pathophysiological conditions. Curr Drug Metab 2013; 13:1327-44. [PMID: 22746301 DOI: 10.2174/138920012803341302] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 04/04/2012] [Accepted: 04/19/2012] [Indexed: 12/19/2022]
Abstract
Expression and activity of several key drug metabolizing enzymes (DMEs) and transporters are altered in various pathophysiological conditions, leading to altered drug metabolism and disposition. This can have profound impact on the pharmacotherapy of widely used clinically relevant medications in terms of safety and efficacy by causing inter-individual variabilities in drug responses. This review article highlights altered drug disposition in inflammation and infectious diseases, and commonly encountered disorders such as cancer, obesity/diabetes, fatty liver diseases, cardiovascular diseases and rheumatoid arthritis. Many of the clinically relevant drugs have a narrow therapeutic index. Thus any changes in the disposition of these drugs may lead to reduced efficacy and increased toxicity. The implications of changes in DMEs and transporters on the pharmacokinetics/pharmacodynamics of clinically-relevant medications are also discussed. Inflammation-mediated release of pro-inflammatory cytokines and activation of toll-like receptors (TLRs) are known to play a major role in down-regulation of DMEs and transporters. Although the mechanism by which this occurs is unclear, several studies have shown that inflammation-associated cell-signaling pathway and its interaction with basal transcription factors and nuclear receptors in regulation of DMEs and transporters play a significant role in altered drug metabolism. Altered regulation of DMEs and transporters in a multitude of disease states will contribute towards future development of powerful in vitro and in vivo tools in predicting the drug response and opt for better drug design and development. The goal is to facilitate a better understanding of the mechanistic details underlying the regulation of DMEs and transporters in pathophysiological conditions.
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Affiliation(s)
- Adarsh Gandhi
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, TX 77030, USA
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Microglial activation decreases retention of the protease inhibitor saquinavir: implications for HIV treatment. J Neuroinflammation 2013; 10:58. [PMID: 23642074 PMCID: PMC3651327 DOI: 10.1186/1742-2094-10-58] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 04/12/2013] [Indexed: 12/13/2022] Open
Abstract
Background Active HIV infection within the central nervous system (CNS) is confined primarily to microglia. The glial cell compartment acts as a viral reservoir behind the blood-brain barrier. It provides an additional roadblock to effective pharmacological treatment via expression of multiple drug efflux transporters, including P-glycoprotein. HIV/AIDS patients frequently suffer bacterial and viral co-infections, leading to deregulation of glial cell function and release of pro-inflammatory mediators including cytokines, chemokines, and nitric oxide. Methods To better define the role of inflammation in decreased HIV drug accumulation into CNS targets, accumulation of the antiretroviral saquinavir was examined in purified cultures of rodent microglia exposed to the prototypical inflammatory mediator lipopolysaccharide (LPS). Results [3H]-Saquinavir accumulation by microglia was rapid, and was increased up to two-fold in the presence of the specific P-glycoprotein inhibitor, PSC833. After six or 24 hours of exposure to 10 ng/ml LPS, saquinavir accumulation was decreased by up to 45%. LPS did not directly inhibit saquinavir transport, and did not affect P-glycoprotein protein expression. LPS exposure did not alter RNA and/or protein expression of other transporters including multidrug resistance-associated protein 1 and several solute carrier uptake transporters. Conclusions The decrease in saquinavir accumulation in microglia following treatment with LPS is likely multi-factorial, since drug accumulation was attenuated by inhibitors of NF-κβ and the MEK1/2 pathway in the microglia cell line HAPI, and in primary microglia cultures from toll-like receptor 4 deficient mice. These data provide new pharmacological insights into why microglia act as a difficult-to-treat viral sanctuary site.
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Ashraf T, Kis O, Banerjee N, Bendayan R. Drug Transporters At Brain Barriers. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2013. [DOI: 10.1007/978-1-4614-4711-5_2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Ronaldson PT, Davis TP. Blood-brain barrier integrity and glial support: mechanisms that can be targeted for novel therapeutic approaches in stroke. Curr Pharm Des 2012; 18:3624-44. [PMID: 22574987 DOI: 10.2174/138161212802002625] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/06/2012] [Indexed: 12/31/2022]
Abstract
The blood-brain barrier (BBB) is a critical regulator of brain homeostasis. Additionally, the BBB is the most significant obstacle to effective CNS drug delivery. It possesses specific charcteristics (i.e., tight junction protein complexes, influx and efflux transporters) that control permeation of circulating solutes including therapeutic agents. In order to form this "barrier," brain microvascular endothelial cells require support of adjacent astrocytes and microglia. This intricate relationship also occurs between endothelial cells and other cell types and structures of the CNS (i.e., pericytes, neurons, extracellular matrix), which implies existence of a "neurovascular unit." Ischemic stroke can disrupt the neurovascular unit at both the structural and functional level, which leads to an increase in leak across the BBB. Recent studies have identified several pathophysiological mechanisms (i.e., oxidative stress, activation of cytokine-mediated intracellular signaling systems) that mediate changes in the neurovascular unit during ischemic stroke. This review summarizes current knowledge in this area and emphasizes pathways (i.e., oxidative stress, cytokine-mediated intracellular signaling, glial-expressed receptors/targets) that can be manipulated pharmacologically for i) preservation of BBB and glial integrity during ischemic stroke and ii) control of drug permeation and/or transport across the BBB. Targeting these pathways present a novel opportunity for optimization of CNS delivery of therapeutics in the setting of ischemic stroke.
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Affiliation(s)
- Patrick T Ronaldson
- Department of Medical Pharmacology, College of Medicine, University of Arizona, 1501 North Campbell Avenue, P.O. Box 245050, Tucson, AZ 85724-5050, USA.
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Harati R, Villégier AS, Banks WA, Mabondzo A. Susceptibility of juvenile and adult blood-brain barrier to endothelin-1: regulation of P-glycoprotein and breast cancer resistance protein expression and transport activity. J Neuroinflammation 2012; 9:273. [PMID: 23253775 PMCID: PMC3547749 DOI: 10.1186/1742-2094-9-273] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 11/07/2012] [Indexed: 12/12/2022] Open
Abstract
Background P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) play a critical role in keeping neurotoxic substances from entering the brain. We and others have previously reported an impact of inflammation on the regulation of adult blood–brain barrier (BBB) efflux transporters. However, studies in children have not been done. From the pediatric clinical perspective, it is important to understand how the central nervous system (CNS) and BBB drug efflux transporters differ in childhood from those of adults under normal and inflammatory conditions. Therefore, we examined and compared the regulation of P-gp and BCRP expression and transport activity in young and adult BBB and investigated the molecular mechanisms underlying inflammatory responses. Methods Rats at postnatal day (P) P21 and P84, corresponding to the juvenile and adult stages of human brain maturation, respectively, were treated with endothelin-1 (ET-1) given by the intracerebroventricular (icv) route. Twenty-four hours later, we measured P-gp and BCRP protein expression in isolated brain capillary by immunoblotting as well as by transport activity in vivo by measuring the unbound drug partitioning coefficient of the brain (Kp,uu,brain) of known efflux transporter substrates administered intravenously. Glial activation was measured by immunohistochemistry. The release of cytokines/chemokines (interleukins-1α, 1-β (IL-1β), -6 (IL-6), -10 (IL-10), monocyte chemoattractant protein (MCP-1/CCL2), fractalkine and tissue inhibitor of metalloproteinases-1 (TIMP-1)) were simultaneously measured in brain and serum samples using the Agilent Technology cytokine microarray. Results We found that juvenile and adult BBBs exhibited similar P-gp and BCRP transport activities in the normal physiological conditions. However, long-term exposure of the juvenile brain to low-dose of ET-1 did not change BBB P-gp transport activity but tended to decrease BCRP transport activity in the juvenile brain, while a significant increase of the activity of both transporters was evidenced at the BBB in the adult brain. Moreover, juvenile and adult brain showed differences in their expression profiles of cytokines and chemokines mediated by ET-1. Conclusions BBB transporter activity during neuroinflammation differs between the juvenile and adult brains. These findings emphasize the importance of considering differential P-gp and BCRP transport regulation mechanisms between adult and juvenile BBB in the context of neuroinflammation.
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Affiliation(s)
- Rania Harati
- CEA, Direction des Sciences du Vivant, iBiTec-S, Service de Pharmacologie et d'Immunoanalyse, Gif-sur-Yvette, France
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Zuloaga KL, Swift SN, Gonzales RJ, Wu TJ, Handa RJ. The androgen metabolite, 5α-androstane-3β,17β-diol, decreases cytokine-induced cyclooxygenase-2, vascular cell adhesion molecule-1 expression, and P-glycoprotein expression in male human brain microvascular endothelial cells. Endocrinology 2012; 153:5949-60. [PMID: 23117931 PMCID: PMC3512076 DOI: 10.1210/en.2012-1316] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
P-glycoprotein (Pgp), a multiple drug resistance transporter expressed by vascular endothelial cells, is a key component of the blood-brain barrier and has been shown to increase after inflammation. The nonaromatizable androgen, dihydrotestosterone (DHT), decreases inflammatory markers in vascular smooth muscle cells, independent of androgen receptor (AR) stimulation. The principal metabolite of DHT, 5α-androstane-3β,17β-diol (3β-diol), activates estrogen receptor (ER)β and similarly decreases inflammatory markers in vascular cells. Therefore, we tested the hypothesis that either DHT or 3β-diol decrease cytokine-induced proinflammatory mediators, vascular cell adhesion molecule-1 (VCAM-1) and cyclooxygenase-2 (COX-2), to regulate Pgp expression in male primary human brain microvascular endothelial cells (HBMECs). Using RT-qPCR, the mRNAs for AR, ERα, and ERβ and steroid metabolizing enzymes necessary for DHT conversion to 3β-diol were detected in male HBMECs demonstrating that the enzymes and receptors for production of and responsiveness to 3β-diol are present. Western analysis showed that 3β-diol reduced COX-2 and Pgp expression; the effect on Pgp was inhibited by the ER antagonist, ICI-182,780. IL-1β-caused an increase in COX-2 and VCAM-1 that was reduced by either DHT or 3β-diol. 3β-diol also decreased cytokine-induced Pgp expression. ICI-182,780 blocked the effect of 3β-diol on COX-2 and VCAM-1, but not Pgp expression. Therefore, in cytokine-stimulated male HBMECs, the effect of 3β-diol on proinflammatory mediator expression is ER dependent, whereas its effect on Pgp expression is ER independent. These studies suggest a novel role of 3β-diol in regulating blood-brain barrier function and support the concept that 3β-diol can be protective against proinflammatory mediator stimulation.
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Affiliation(s)
- Kristen L Zuloaga
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, Phoenix, AZ 85004-2157, USA
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Dave RS. Morphine affects HIV-induced inflammatory response without influencing viral replication in human monocyte-derived macrophages. ACTA ACUST UNITED AC 2012; 64:228-36. [PMID: 22066570 DOI: 10.1111/j.1574-695x.2011.00894.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Opiate-abusing individuals are in the top three risk-factor groups for HIV infection. In fact, almost 30% of HIV-infected individuals in the USA are reported to abuse opiates, highlighting the intersection of drugs of abuse with HIV/AIDS. Opiate-abusers are cognitively impaired and suffer from neurological dysfunctions that may lead to high-risk sexual behavior, poor adherence to antiretroviral regimens, and hepatitis-C virus infection. Collectively, these factors may contribute to accelerated HIV central nervous system (CNS) disease progression. To understand the role of morphine in disease progression, we sought to determine whether morphine influences HIV-induced inflammation or viral replication in human monocyte-derived macrophages (h-mdms) and MAGI cells infected with HIV and exposed to morphine. Chronic morphine exposure of HIV-infected h-mdms led to significant alterations in the secretion of IL-6 and monocyte chemoattractant protein 2 (MCP-2). Morphine enhanced IL-6 secretion and blunted MCP-2 secretion from HIV-infected h-mdms. However, exposure of HIV-infected h-mdms to morphine had no effect on tumor necrosis factor alpha secretion. Morphine had no effect on later stages of viral replication in HIV-infected h-mdms. Morphine had a potentially additive effect on the HIV-induced production of IL-6 and delayed HIV-induced MCP-2 production. These results suggest that in HIV-infected opiate-abusers, enhanced CNS inflammation might result even when HIV disease is controlled.
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Affiliation(s)
- Rajnish S Dave
- Department of Neuroscience, Center for Neurovirology, Temple University, MERB 774A, 3500 North Broad Street, Philadelphia, PA 19140, USA.
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Aronica E, Sisodiya SM, Gorter JA. Cerebral expression of drug transporters in epilepsy. Adv Drug Deliv Rev 2012; 64:919-29. [PMID: 22138133 DOI: 10.1016/j.addr.2011.11.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2011] [Revised: 10/03/2011] [Accepted: 11/20/2011] [Indexed: 12/26/2022]
Abstract
Over-expression of drug efflux transporters at the level of the blood-brain barrier (BBB) has been proposed as a mechanism responsible for multidrug resistance. Drug transporters in epileptogenic tissue are not only expressed in endothelial cells at the BBB, but also in other brain parenchymal cells, such as astrocytes, microglia and neurons, suggesting a complex cell type-specific regulation under pathological conditions associated with epilepsy. This review focuses on the cerebral expression patterns of several classes of well-known membrane drug transporters such as P-glycoprotein (Pgp), and multidrug resistance-associated proteins (MRPs) in the epileptogenic brain. Both experimental and clinical evidence of epilepsy-associated cerebral drug transporter regulation and the possible mechanisms underlying drug transporter regulation are discussed. Knowledge of the cerebral expression patterns of drug transporters in normal and epileptogenic brain will provide relevant information to guide strategies attempting to overcome drug resistance by targeting specific transporters.
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Affiliation(s)
- Eleonora Aronica
- Department of (Neuro) Pathology, Academic Medical Center, University of Amsterdam, The Netherlands.
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66
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Wong HL, Wu XY, Bendayan R. Nanotechnological advances for the delivery of CNS therapeutics. Adv Drug Deliv Rev 2012; 64:686-700. [PMID: 22100125 DOI: 10.1016/j.addr.2011.10.007] [Citation(s) in RCA: 341] [Impact Index Per Article: 28.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/27/2011] [Indexed: 12/18/2022]
Abstract
Effective non-invasive treatment of neurological diseases is often limited by the poor access of therapeutic agents into the central nervous system (CNS). The majority of drugs and biotechnological agents do not readily permeate into brain parenchyma due to the presence of two anatomical and biochemical dynamic barriers: the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCSFB). Therefore, one of the most significant challenges facing CNS drug development is the availability of effective brain targeting technology. Recent advances in nanotechnology have provided promising solutions to this challenge. Several nanocarriers ranging from the more established systems, e.g. polymeric nanoparticles, solid lipid nanoparticles, liposomes, micelles to the newer systems, e.g. dendrimers, nanogels, nanoemulsions and nanosuspensions have been studied for the delivery of CNS therapeutics. Many of these nanomedicines can be effectively transported across various in vitro and in vivo BBB models by endocytosis and/or transcytosis, and demonstrated early preclinical success for the management of CNS conditions such as brain tumors, HIV encephalopathy, Alzheimer's disease and acute ischemic stroke. Future development of CNS nanomedicines need to focus on increasing their drug-trafficking performance and specificity for brain tissue using novel targeting moieties, improving their BBB permeability and reducing their neurotoxicity.
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Xu H, Bae M, Tovar-y-Romo LB, Patel N, Bandaru VVR, Pomerantz D, Steiner JP, Haughey NJ. The human immunodeficiency virus coat protein gp120 promotes forward trafficking and surface clustering of NMDA receptors in membrane microdomains. J Neurosci 2011; 31:17074-90. [PMID: 22114277 PMCID: PMC3254245 DOI: 10.1523/jneurosci.4072-11.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/28/2011] [Accepted: 09/29/2011] [Indexed: 11/21/2022] Open
Abstract
Infection by the human immunodeficiency virus (HIV) can result in debilitating neurological syndromes collectively known as HIV-associated neurocognitive disorders. Although the HIV coat protein gp120 has been identified as a potent neurotoxin that enhances NMDA receptor function, the exact mechanisms for this effect are not known. Here we provide evidence that gp120 activates two separate signaling pathways that converge to enhance NMDA-evoked calcium flux by clustering NMDA receptors in modified membrane microdomains. gp120 enlarged and stabilized the structure of lipid microdomains on dendrites by mechanisms that involved a redox-regulated translocation of a sphingomyelin hydrolase (neutral sphingomyelinase-2) to the plasma membrane. A concurrent pathway was activated that accelerated the forward traffic of NMDA receptors by a PKA-dependent phosphorylation of the NR1 C-terminal serine 897 (masks an ER retention signal), followed by a PKC-dependent phosphorylation of serine 896 (important for surface expression). NMDA receptors were preferentially targeted to synapses and clustered in modified membrane microdomains. In these conditions, NMDA receptors were unable to laterally disperse and did not internalize, even in response to strong agonist induction. Focal NMDA-evoked calcium bursts were enhanced by threefold in these regions. Inhibiting membrane modification or NR1 phosphorylation prevented gp120 from accelerating the surface localization of NMDA receptors. Disrupting the structure of membrane microdomains after gp120 treatments restored the ability of NMDA receptors to disperse and internalize. These findings demonstrate that gp120 contributes to synaptic dysfunction in the setting of HIV infection by interfering with NMDA receptor trafficking.
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Affiliation(s)
- Hangxiu Xu
- Departments of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections and
| | - Mihyun Bae
- Departments of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections and
| | - Luis B. Tovar-y-Romo
- Departments of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections and
| | - Neha Patel
- Departments of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections and
| | | | - Daniel Pomerantz
- Departments of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections and
| | - Joseph P. Steiner
- Departments of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections and
| | - Norman J. Haughey
- Departments of Neurology, Richard T. Johnson Division of Neuroimmunology and Neurological Infections and
- Psychiatry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287
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Naud J, Laurin LP, Michaud J, Beauchemin S, Leblond FA, Pichette V. Effects of Chronic Renal Failure on Brain Drug Transporters in Rats. Drug Metab Dispos 2011; 40:39-46. [DOI: 10.1124/dmd.111.041145] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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HIV-1 envelope protein gp120 up regulates CCL5 production in astrocytes which can be circumvented by inhibitors of NF-κB pathway. Biochem Biophys Res Commun 2011; 414:112-7. [PMID: 21945445 DOI: 10.1016/j.bbrc.2011.09.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2011] [Accepted: 09/07/2011] [Indexed: 12/15/2022]
Abstract
HIV associated neurological disorders (HAND) is a common neurological complication in patients infected with HIV. The proinflammatory cytokines and chemokines produced by astrocytes play a pivotal role in neuroinflammatory processes in the brain and viral envelope gp120 has been implicated in this process. In view of increased levels of CCL5 observed in the CSF of HIV-1 infected patients, we studied the effects of gp120 on CCL5 expression in astrocytes and the possible mechanisms responsible for those effects. Transfection of the SVGA astrocyte cell line with a plasmid encoding gp120 resulted in a time-dependent increase in expression levels of CCL5 in terms of mRNA and protein by 24.6 ± 2.67- and 35.2 ± 6.1-fold, respectively. The fluorescent images showed localization of CCL5 in the processes of the astrocytes. The gp120-specific siRNA abrogated the gp120-mediated increase in CCL5 expression. We also explored a possible mechanism for the effects of gp120 on CCL5 expression. Using a specific inhibitor for the NF-κB pathway, we demonstrated that levels of gp120 induction of CCL5 expression can be abrogated by 44.6 ± 4.2% at the level of mRNA and 51.8 ± 5.0% at the protein level. This was further confirmed by knocking down NF-κB through the use of siRNA.
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Ashraf T, Ronaldson PT, Persidsky Y, Bendayan R. Regulation of P-glycoprotein by human immunodeficiency virus-1 in primary cultures of human fetal astrocytes. J Neurosci Res 2011; 89:1773-82. [PMID: 21826700 DOI: 10.1002/jnr.22720] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 04/28/2011] [Accepted: 05/19/2011] [Indexed: 01/04/2023]
Abstract
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.
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Affiliation(s)
- Tamima Ashraf
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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71
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Ronaldson PT, Davis TP. Targeting blood-brain barrier changes during inflammatory pain: an opportunity for optimizing CNS drug delivery. Ther Deliv 2011; 2:1015-41. [PMID: 22468221 PMCID: PMC3313594 DOI: 10.4155/tde.11.67] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The blood-brain barrier (BBB) is the most significant obstacle to effective CNS drug delivery. It possesses structural and biochemical features (i.e., tight-junction protein complexes and, influx and efflux transporters) that restrict xenobiotic permeation. Pathophysiological stressors (i.e., peripheral inflammatory pain) can alter BBB tight junctions and transporters, which leads to drug-permeation changes. This is especially critical for opioids, which require precise CNS concentrations to be safe and effective analgesics. Recent studies have identified molecular targets (i.e., endogenous transporters and intracellular signaling systems) that can be exploited for optimization of CNS drug delivery. This article summarizes current knowledge in this area and emphasizes those targets that present the greatest opportunity for controlling drug permeation and/or drug transport across the BBB in an effort to achieve optimal CNS opioid delivery.
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Affiliation(s)
- Patrick T Ronaldson
- Department of Medical Pharmacology, College of Medicine, University of Arizona, 1501 N Campbell Avenue, PO Box 245050, Tucso, AZ, USA.
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Shah A, Verma AS, Patel KH, Noel R, Rivera-Amill V, Silverstein PS, Chaudhary S, Bhat HK, Stamatatos L, Singh DP, Buch S, Kumar A. HIV-1 gp120 induces expression of IL-6 through a nuclear factor-kappa B-dependent mechanism: suppression by gp120 specific small interfering RNA. PLoS One 2011; 6:e21261. [PMID: 21712995 PMCID: PMC3119684 DOI: 10.1371/journal.pone.0021261] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 05/25/2011] [Indexed: 12/21/2022] Open
Abstract
In addition to its role in virus entry, HIV-1 gp120 has also been implicated in HIV-associated neurocognitive disorders. However, the mechanism(s) responsible for gp120-mediated neuroinflammation remain undefined. In view of increased levels of IL-6 in HIV-positive individuals with neurological manifestations, we sought to address whether gp120 is involved in IL-6 over-expression in astrocytes. Transfection of a human astrocyte cell line with a plasmid encoding gp120 resulted in increased expression of IL-6 at the levels of mRNA and protein by 51.3±2.1 and 11.6±2.2 fold respectively; this effect of gp120 on IL-6 expression was also demonstrated using primary human fetal astrocytes. A similar effect on IL-6 expression was observed when primary astrocytes were treated with gp120 protein derived from different strains of X4 and R5 tropic HIV-1. The induction of IL-6 could be abrogated by use of gp120-specific siRNA. Furthermore, this study showed that the NF-κB pathway is involved in gp120-mediated IL-6 over-expression, as IKK-2 and IKKβ inhibitors inhibited IL-6 expression by 56.5% and 60.8%, respectively. These results were also confirmed through the use of NF-κB specific siRNA. We also showed that gp120 could increase the phosphorylation of IκBα. Furthermore, gp120 transfection in the SVGA cells increased translocation of NF-κB from cytoplasm to nucleus. These results demonstrate that HIV-1 gp120-mediated over-expression of IL-6 in astrocytes is one mechanism responsible for neuroinflammation in HIV-infected individuals and this is mediated by the NF-κB pathway.
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Affiliation(s)
- Ankit Shah
- Division of Pharmacology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Ashish S. Verma
- Division of Pharmacology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Kalpeshkumar H. Patel
- Division of Pharmacology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | | | | | - Peter S. Silverstein
- Division of Pharmacology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | | | - Hari K. Bhat
- Division of Pharmacology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
| | - Leonidas Stamatatos
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Dhirendra P. Singh
- University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Shilpa Buch
- University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Anil Kumar
- Division of Pharmacology, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri, United States of America
- * E-mail:
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Santosuosso M, Righi E, Hill ED, Leblanc PR, Kodish B, Mylvaganam HN, Siddappa NB, Stevceva L, Hu SL, Ghebremichael M, Chenine AL, Hovav AH, Ruprecht RM, Poznansky MC. R5-SHIV induces multiple defects in T cell function during early infection of rhesus macaques including accumulation of T reg cells in lymph nodes. PLoS One 2011; 6:e18465. [PMID: 21483689 PMCID: PMC3071731 DOI: 10.1371/journal.pone.0018465] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Accepted: 03/09/2011] [Indexed: 11/18/2022] Open
Abstract
Background HIV-1 is a pathogen that T cell responses fail to control. HIV-1gp120 is the surface viral envelope glycoprotein that interacts with CD4 T cells and mediates entry. HIV-1gp120 has been implicated in immune dysregulatory functions that may limit anti-HIV antigen-specific T cell responses. We hypothesized that in the context of early SHIV infection, immune dysregulation of antigen-specific T-effector cell and regulatory functions would be detectable and that these would be associated or correlated with measurable concentrations of HIV-1gp120 in lymphoid tissues. Methods Rhesus macaques were intravaginally inoculated with a Clade C CCR5-tropic simian-human immunodeficiency virus, SHIV-1157ipd3N4. HIV-1gp120 levels, antigen-specificity, levels of apoptosis/anergy and frequency and function of Tregs were examined in lymph node and blood derived T cells at 5 and 12 weeks post inoculation. Results/Conclusions We observed reduced responses to Gag in CD4 and gp120 in CD8 lymph node-derived T cells compared to the peripheral blood at 5 weeks post-inoculation. Reduced antigen-specific responses were associated with higher levels of PD-1 on lymph node-derived CD4 T cells as compared to peripheral blood and uninfected lymph node-derived CD4 T cells. Lymph nodes contained increased numbers of Tregs as compared to peripheral blood, which positively correlated with gp120 levels; T regulatory cell depletion restored CD8 T cell responses to Gag but not to gp120. HIV gp120 was also able to induce T regulatory cell chemotaxis in a dose-dependent, CCR5-mediated manner. These studies contribute to our broader understanding of the ways in which HIV-1 dysregulates T cell function and localization during early infection.
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Affiliation(s)
- Michael Santosuosso
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Elda Righi
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - E. David Hill
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Pierre R. Leblanc
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Brett Kodish
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Hari N. Mylvaganam
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Nagadenahalli B. Siddappa
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Liljana Stevceva
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
| | - Shiu-Lok Hu
- Department of Pharmaceutics, University of Washington, Seattle, Washington, United States of America
| | - Musie Ghebremichael
- Department of Biostatistics and Computational Biology, Harvard School of Public Health and Dana Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Agnes-L. Chenine
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Avi-Hai Hovav
- Faculty of Dental Medicine, Institute of Dental Sciences, Hebrew University, Jerusalem, Israel
| | - Ruth M. Ruprecht
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Mark C. Poznansky
- Infectious Diseases Medicine Division, Vaccine and Immunotherapy Center, Massachusetts General Hospital, Charlestown, Massachusetts, United States of America
- * E-mail:
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Abstract
The blood-brain barrier (BBB) physically and metabolically functions as a neurovascular interface between the brain parenchyma and the systemic circulation, and regulates the permeability of several endogenous substrates and xenobiotics in and out of the central nervous system. Several membrane-associated transport proteins, such as P-glycoprotein (P-gp), multidrug resistance-associated proteins, breast cancer resistance protein, and organic anion transporting polypeptides, have been characterized at the BBB and identified to play a major role in regulating the brain bioavailability of several pharmacological agents. This chapter reviews several well-established techniques for the study of the molecular expression, cellular localization, and functional activity of transport proteins in primary and immortalized cell culture systems of the BBB. In particular, we describe the molecular characterization of P-gp/MDR1 at the transcript level using semiquantitative polymerase chain reaction (PCR), at the protein level using immunoblotting, and at the cellular level using immunofluorescence. In addition, the uptake/efflux and transepithelial flux studies, which characterize P-gp transport activity, are described.
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Shah A, Kumar A. HIV-1 gp120-mediated increases in IL-8 production in astrocytes are mediated through the NF-κB pathway and can be silenced by gp120-specific siRNA. J Neuroinflammation 2010; 7:96. [PMID: 21190575 PMCID: PMC3023744 DOI: 10.1186/1742-2094-7-96] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 12/29/2010] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND The exact mechanism underlying HIV-associated neurocognitive disorders still remains largely unresolved. However, viral genes (for example gp120 and tat) and their effect on cytokine/chemokine expressions have been linked with neuroinflammation. Conversely, interlekin-8 (IL-8) is a known proinflammatory chemokine and is known to be over-expressed in human brain microvascular endothelial cells in response to gp120. In this study, we sought to address whether HIV-1gp120 could affect IL-8 expression in astrocytes and whether the NF-κB pathway is involved in this phenomenon. METHODS SVGA astrocytes were transfected with a plasmid expressing HIV-1 pSyn gp120 JR-FL using Lipofectamine2000. The cells were harvested at different time points after transfection, and total cellular RNA was used for quantification of IL-8 using a real time PCR. IL-8 protein expression was also determined in supernatants collected at different time points after transfection. Involvement of the NF-κB pathway was addressed using both pharmacological inhibitors and an siRNA approach. In order to explore gene specificity, gp120-specific siRNAs were designed and IL-8 expression was monitored at both mRNA and protein levels. RESULTS Gp120 increased IL-8 expression both at mRNA and protein levels by 7.1 ± 1.04 and 2.41 ± 0.35 fold at 6 and 48 hours post-transfection, respectively. This increase was time-dependent and was abrogated by use of gp120-specific siRNA. We have also shown that the NF-κB pathway is involved in gp120-mediated IL-8 overexpression as IKK-2 and IKKβ inhibitors inhibited IL-8 expression by 63.5% and 57.5%, respectively at the mRNA level, and by 67.3% and 58.6% at the protein level. These results were also confirmed with use of NF-κB-specific siRNA. CONCLUSION These results indicate that gp120 can modulate expression of a pro-inflammatory chemokine (IL-8) in astrocytes in a time-dependent manner with significant up-regulation at different times. This phenomenon is specific and is mediated by the NF-κB pathway.
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Affiliation(s)
- Ankit Shah
- Division of Pharmacology and Toxicology, UMKC-School of Pharmacy, Kansas City, MO 64108, USA
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Sorce S, Myburgh R, Krause KH. The chemokine receptor CCR5 in the central nervous system. Prog Neurobiol 2010; 93:297-311. [PMID: 21163326 DOI: 10.1016/j.pneurobio.2010.12.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 11/29/2010] [Accepted: 12/07/2010] [Indexed: 02/04/2023]
Abstract
The expression and the role of the chemokine receptor CCR5 have been mainly studied in the context of HIV infection. However, this protein is also expressed in the brain, where it can be crucial in determining the outcome in response to different insults. CCR5 expression can be deleterious or protective in controlling the progression of certain infections in the CNS, but it is also emerging that it could play a role in non-infectious diseases. In particular, it appears that, in addition to modulating immune responses, CCR5 can influence neuronal survival. Here, we summarize the present knowledge about the expression of CCR5 in the brain and highlight recent findings suggesting its possible involvement in neuroprotective mechanisms.
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Affiliation(s)
- Silvia Sorce
- Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Rue Michel-Servet 1, 1211 Geneva-4, Switzerland
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Hahn YK, Vo P, Fitting S, Block ML, Hauser KF, Knapp PE. beta-Chemokine production by neural and glial progenitor cells is enhanced by HIV-1 Tat: effects on microglial migration. J Neurochem 2010; 114:97-109. [PMID: 20403075 PMCID: PMC2992981 DOI: 10.1111/j.1471-4159.2010.06744.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human immunodeficiency virus (HIV)-1 neuropathology results from collective effects of viral proteins and inflammatory mediators on several cell types. Significant damage is mediated indirectly through inflammatory conditions promulgated by glial cells, including microglia that are productively infected by HIV-1, and astroglia. Neural and glial progenitors exist in both developing and adult brains. To determine whether progenitors are targets of HIV-1, a multi-plex assay was performed to assess chemokine/cytokine expression after treatment with viral proteins transactivator of transcription (Tat) or glycoprotein 120 (gp120). In the initial screen, ten analytes were basally released by murine striatal progenitors. The beta-chemokines CCL5/regulated upon activation, normal T cell expressed and secreted, CCL3/macrophage inflammatory protein-1alpha, and CCL4/macrophage inflammatory protein-1beta were increased by 12-h exposure to HIV-1 Tat. Secreted factors from Tat-treated progenitors were chemoattractive towards microglia, an effect blocked by 2D7 anti-CCR5 antibody pre-treatment. Tat and opiates have interactive effects on astroglial chemokine secretion, but this interaction did not occur in progenitors. gp120 did not affect chemokine/cytokine release, although both CCR5 and CXCR4, which serve as gp120 co-receptors, were detected in progenitors. We postulate that chemokine production by progenitors may be a normal, adaptive process that encourages immune inspection of newly generated cells. Pathogens such as HIV might usurp this function to create a maladaptive state, especially during development or regeneration, when progenitors are numerous.
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Affiliation(s)
- Yun Kyung Hahn
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Phu Vo
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Sylvia Fitting
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Michelle L. Block
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Kurt F. Hauser
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Pamela E. Knapp
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298 USA
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA 23298 USA
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Kis O, Zastre JA, Ramaswamy M, Bendayan R. pH Dependence of Organic Anion-Transporting Polypeptide 2B1 in Caco-2 Cells: Potential Role in Antiretroviral Drug Oral Bioavailability and Drug–Drug Interactions. J Pharmacol Exp Ther 2010; 334:1009-22. [DOI: 10.1124/jpet.110.166314] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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Weiss J, Haefeli WE. Impact of ATP-binding cassette transporters on human immunodeficiency virus therapy. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 280:219-79. [PMID: 20797684 DOI: 10.1016/s1937-6448(10)80005-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Even though potent antiretrovirals are available against human immunodeficiency virus (HIV)-1 infection, therapy fails in a significant fraction of patients. Among the most relevant reasons for treatment failure are drug toxicity and side effects, but also the development of viral resistance towards the drugs applied. Efflux by ATP-binding cassette (ABC-) transporters represents one major mechanism influencing the pharmacokinetics of antiretroviral drugs and particularly their distribution, thus modifiying the concentration within the infected cells, that is, at the site of action. Moreover, drug-drug interactions may occur at the level of these transporters and modulate their activity or expression thus influencing the efficacy and toxicity of the substrate drugs. This review summarizes current knowledge on the interaction of antiretrovirals used for HIV-1 therapy with ABC-transporters and highlights the impact of ABC-transporters for cellular resistance and therapeutic success. Moreover, the suitability of different cell models for studying the interaction of antiretrovirals with ABC-transporters is discussed.
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Affiliation(s)
- Johanna Weiss
- Department of Clinical Pharmacology and Pharmacoepidemiology, University of Heidelberg, Heidelberg, Germany
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Wong HL, Chattopadhyay N, Wu XY, Bendayan R. Nanotechnology applications for improved delivery of antiretroviral drugs to the brain. Adv Drug Deliv Rev 2010; 62:503-17. [PMID: 19914319 DOI: 10.1016/j.addr.2009.11.020] [Citation(s) in RCA: 130] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Accepted: 09/14/2009] [Indexed: 01/16/2023]
Abstract
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.
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Intact lipid rafts regulate HIV-1 Tat protein-induced activation of the Rho signaling and upregulation of P-glycoprotein in brain endothelial cells. J Cereb Blood Flow Metab 2010; 30:522-33. [PMID: 19794400 PMCID: PMC2949153 DOI: 10.1038/jcbfm.2009.214] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Rho signaling has an essential function in human immunodeficiency virus (HIV)-1-mediated disruption of the integrity of the blood-brain barrier (BBB). However, it is unknown how membrane domains, such as lipid rafts, can influence HIV-1-mediated activation of the Rho pathway and how these processes can affect the expression of the efflux transporters at the BBB level. This study is focused on the function of HIV-1 protein Tat in activation of the Rho signaling and upregulation of P-glycoprotein (P-gp) in human brain endothelial cells. Treatment with Tat markedly elevated GTP-RhoA levels and the potential downstream effectors, such as myosin phosphatase target subunit 1 and myosin light chain. In addition, Tat upregulated expression and promoter activity of P-gp as well as its efflux function. Inhibition of the Rho signaling cascade effectively blocked P-gp overexpression at the level of promoter activity. Disruption of lipid rafts by depletion of membrane cholesterol by methyl-beta-cyclodextrin, but not caveolin-1 silencing, also abolished Tat-mediated RhoA activation and P-gp upregulation. The present data indicate the critical function of intact lipid rafts and the Rho signaling in HIV-1-mediated upregulation of P-gp and potential development of drug resistance in brain endothelial cells.
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Borjabad A, Brooks AI, Volsky DJ. Gene expression profiles of HIV-1-infected glia and brain: toward better understanding of the role of astrocytes in HIV-1-associated neurocognitive disorders. J Neuroimmune Pharmacol 2010; 5:44-62. [PMID: 19697136 PMCID: PMC3107560 DOI: 10.1007/s11481-009-9167-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 07/27/2009] [Indexed: 12/17/2022]
Abstract
Astrocytes are the major cellular component of the central nervous system (CNS), and they play multiple roles in brain development, normal brain function, and CNS responses to pathogens and injury. The functional versatility of astrocytes is linked to their ability to respond to a wide array of biological stimuli through finely orchestrated changes in cellular gene expression. Dysregulation of gene expression programs, generally by chronic exposure to pathogenic stimuli, may lead to dysfunction of astrocytes and contribute to neuropathogenesis. Here, we review studies that employ functional genomics to characterize the effects of HIV-1 and viral pathogenic proteins on cellular gene expression in astrocytes in vitro. We also present the first microarray analysis of primary mouse astrocytes exposed to HIV-1 in culture. In spite of different experimental conditions and microarray platforms used, comparison of the astrocyte array data sets reveals several common gene-regulatory changes that may underlie responses of these cells to HIV-1 and its proteins. We also compared the transcriptional profiles of astrocytes with those obtained in analyses of brain tissues of patients with HIV-1 dementia and macaques infected with simian immunodeficiency virus (SIV). Notably, many of the gene characteristics of responses to HIV-1 in cultured astrocytes were also altered in HIV-1 or SIV-infected brains. Functional genomics, in conjunction with other approaches, may help clarify the role of astrocytes in HIV-1 neuropathogenesis.
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Affiliation(s)
- Alejandra Borjabad
- Molecular Virology Division, St. Luke's-Roosevelt Hospital Center, 432 West 58th Street, Antenucci Building, Room 709, New York, NY 10019, USA
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83
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Ronaldson PT, Ashraf T, Bendayan R. Regulation of Multidrug Resistance Protein 1 by Tumor Necrosis Factor α in Cultured Glial Cells: Involvement of Nuclear Factor-κB and c-Jun N-Terminal Kinase Signaling Pathways. Mol Pharmacol 2010; 77:644-59. [DOI: 10.1124/mol.109.059410] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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84
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Rivera-Amill V, Silverstein PS, Noel RJ, Kumar S, Kumar A. Morphine and rapid disease progression in nonhuman primate model of AIDS: inverse correlation between disease progression and virus evolution. J Neuroimmune Pharmacol 2009; 5:122-32. [PMID: 20013315 DOI: 10.1007/s11481-009-9184-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 11/17/2009] [Indexed: 01/04/2023]
Abstract
HIV and simian immunodeficiency virus (SIV) have a formidable capacity for mutation and adaptation, a characteristic that has contributed to the extensive genetic variability. Evolutionary pressures imposed within the host and the viral capacity to mutate lead to the generation of such variants. To date, very little information is available regarding the evolution of HIV with drug abuse as a cofounding factor. Using our macaque model of drug dependency and AIDS, we have investigated the dynamics of SIV mutations in the genes tat, vpr, envelope, and nef. The results presented in this review, from our laboratory and others, contribute to the overall understanding of how drugs of abuse might influence immune selective pressure contribution to variation in different SIV genes. Additionally, the studies presented could help enlighten the development of HIV vaccines that take into consideration viral diversity.
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85
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X4 human immunodeficiency virus type 1 gp120 down-modulates expression and immunogenicity of codelivered antigens. J Virol 2009; 83:10941-50. [PMID: 19692474 DOI: 10.1128/jvi.00394-09] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In order to increase the immune breadth of human immunodeficiency virus (HIV) vaccines, strategies such as immunization with several HIV antigens or centralized immunogens have been examined. HIV-1 gp120 protein is a major immunogen of HIV and has been routinely considered for inclusion in both present and future AIDS vaccines. However, recent studies proposed that gp120 interferes with the generation of immune response to codelivered antigens. Here, we investigate whether coimmunization with plasmid-encoded gp120 alters the immune response to other coadministered plasmid encoded antigens such as luciferase or ovalbumin in a mouse model. We found that the presence of gp120 leads to a significant reduction in the expression level of the codelivered antigen in vivo. Antigen presentation by antigen-presenting cells was also reduced and resulted in the induction of weak antigen-specific cellular and humoral immune responses. Importantly, gp120-mediated immune interference was observed after administration of the plasmids at the same or at distinct locations. To characterize the region in gp120 mediating these effects, we used plasmid constructs encoding gp120 that lacks the V1V2 loops (DeltaV1V2) or the V3 loop (DeltaV3). After immunization, the DeltaV1V2, but not the DeltaV3 construct, was able to reduce antigen expression, antigen presentation, and subsequently the immunogenicity of the codelivered antigen. The V3 loop dependence of this phenomenon seems to be limited to V3 loops known to interact with the CXCR4 molecule but not with CCR5. Our study presents a novel mechanism by which HIV-1 gp120 interferes with the immune response against coadministered antigen in a polyvalent vaccine preparation.
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86
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von Wedel-Parlow M, Wölte P, Galla HJ. Regulation of major efflux transporters under inflammatory conditions at the blood-brain barrier in vitro. J Neurochem 2009; 111:111-8. [PMID: 19656257 DOI: 10.1111/j.1471-4159.2009.06305.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
ATP-driven efflux transport proteins at the blood-brain barrier protect the healthy brain but impede pharmacotherapy of the disordered CNS. To investigate the question how ATP-binding cassette (ABC)-transporters are regulated during inflammation or infection we analysed the effects of the cytokines tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) on the expression of brain multidrug resistance proteins in primary cultures of porcine brain capillary endothelial cells. We found that TNF-alpha and IL-1beta rapidly decrease Abcg2 (BMDP/BCRP) mRNA expression within 6 h. After 24 and 48 h the mRNA level came back to control values. The mRNA reduction at 6 h was counter-regulated by the anti-inflammatory glucocorticoid hydrocortisone. Abcg2 protein levels were suppressed at prolonged stimulations but not after 6 h of stimulation which correlates with Abcg2 specific substrate uptake measurements. Abcb1 (p-glycoprotein) protein expression was transiently increased after TNF-alpha addition within 6 h of incubation followed by a reduction after 24 and 48 h whereas the Abcb1 mRNA levels were not changed. IL-1beta caused a continuous decrease in protein expression of both ABC-transporters. Long-term treatment with an assumed TNF-alpha-downstream agent, the vasoconstrictor endothelin-1, induced Abcg2 protein expression but suppressed Abcb1. Other efflux pumps like multidrug resistance-associated proteins/Abcc were rarely affected. The present results imply a complex regulation of the two most abundant ABC-transporters at the blood-brain barrier during early inflammation stages suggesting that Abcb1 (p-glycoprotein) is an early target of TNF-alpha-signalling counterbalanced by Abcg2.
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87
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Detergent-resistant globotriaosyl ceramide may define verotoxin/glomeruli-restricted hemolytic uremic syndrome pathology. Kidney Int 2009; 75:1209-1216. [PMID: 19212418 DOI: 10.1038/ki.2009.7] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Verotoxin binding to its receptor, globotriaosyl ceramide(Gb(3)) mediates the glomerular pathology of hemolytic uremic syndrome, but Gb(3) is expressed in both tubular and glomerular cells. Gb(3) within detergent-resistant membranes, an index of glycolipid-cholesterol enriched lipid rafts, is required for in vitro cytotoxicity. We found that verotoxin 1 and 2 binding to human adult renal glomeruli is detergent resistant, whereas the strong verotoxin binding to renal tubules is detergent sensitive. Verotoxin binding to pediatric glomeruli was detergent resistant but binding to adult glomeruli was enhanced, remarkably for some samples, by detergent extraction. Detergent-sensitive glomerular components may provide age-related protection against verotoxin glomerular binding. Mouse glomeruli remained verotoxin unreactive after detergent extraction, whereas tubular binding was lost. Cholesterol extraction induced strong verotoxin binding in poorly reactive adult glomeruli, suggesting cholesterol can mask Gb(3) in glomerular lipid rafts. Binding of the human immunodeficiency virus (HIV) adhesin, gp120 (another Gb(3) ligand) was detergent sensitive, tubule-restricted, and inhibited by verotoxin B subunit pretreatment, and may relate to HIV nephropathy. Our study shows that differential membrane Gb(3) organization in glomeruli and tubules provides a basis for the age- and glomerular-restricted pathology of hemolytic uremic syndrome.
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88
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Varatharajan L, Thomas SA. The transport of anti-HIV drugs across blood-CNS interfaces: summary of current knowledge and recommendations for further research. Antiviral Res 2009; 82:A99-109. [PMID: 19176219 PMCID: PMC2678986 DOI: 10.1016/j.antiviral.2008.12.013] [Citation(s) in RCA: 157] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2008] [Revised: 12/14/2008] [Accepted: 12/21/2008] [Indexed: 02/07/2023]
Abstract
The advent of highly active antiretroviral therapy (HAART), which constitutes HIV protease inhibitors, nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors and nucleotide reverse transcriptase inhibitors, has dramatically reduced the morbidity and mortality associated with human immunodeficiency virus (HIV) infection in resource-rich countries. However, this disease still kills several million people each year. Though the reason for therapeutic failure is multi-factorial, an important concern is the treatment and control of HIV within the central nervous system (CNS). Due to the restricted entry of anti-HIV drugs, the brain is thought to form a viral sanctuary site. This not only results in virological resistance, but also is often associated with the development of complications such as HIV-associated dementia. The CNS delivery of anti-HIV drugs is limited by the blood–brain and blood–CSF interfaces due to a combination of restricted paracellular movement, powerful metabolic enzymes and numerous transporters including members of the ATP binding cassette (ABC) and solute carrier (SLC) superfamilies. A better appreciation of the transporters present at the brain barriers will prove a valuable milestone in understanding the limited brain penetration of anti-HIV drugs in HIV and also aid the development of new anti-HIV drugs and drug combinations, with enhanced efficacy in the CNS. This review aims to summarise current knowledge on the transport of anti-HIV drugs across the blood–brain barrier and the choroid plexus, as well as provide recommendations for future research.
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89
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Ronaldson PT, Persidsky Y, Bendayan R. Regulation of ABC membrane transporters in glial cells: Relevance to the pharmacotherapy of brain HIV-1 infection. Glia 2008; 56:1711-35. [DOI: 10.1002/glia.20725] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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90
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Woodland C, Huang TT, Gryz E, Bendayan R, Fawcett JP. Expression, Activity and Regulation of CYP3A in Human and Rodent Brain. Drug Metab Rev 2008; 40:149-68. [DOI: 10.1080/03602530701836712] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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91
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Roberts DJ, Goralski KB. A critical overview of the influence of inflammation and infection on P-glycoprotein expression and activity in the brain. Expert Opin Drug Metab Toxicol 2008; 4:1245-64. [DOI: 10.1517/17425255.4.10.1245] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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92
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HIV-1-infected astrocytes and the microglial proteome. J Neuroimmune Pharmacol 2008; 3:173-86. [PMID: 18587649 PMCID: PMC2579774 DOI: 10.1007/s11481-008-9110-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Accepted: 05/07/2008] [Indexed: 12/22/2022]
Abstract
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.
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93
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Banerjee S, Walseth TF, Borgmann K, Wu L, Bidasee KR, Kannan MS, Ghorpade A. CD38/cyclic ADP-ribose regulates astrocyte calcium signaling: implications for neuroinflammation and HIV-1-associated dementia. J Neuroimmune Pharmacol 2008; 3:154-64. [PMID: 18581239 DOI: 10.1007/s11481-008-9105-7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2007] [Accepted: 04/02/2008] [Indexed: 11/25/2022]
Abstract
CD38 is a 45-kD ectoenzyme involved in the synthesis of potent calcium (Ca(2+))-mobilizing agents, cyclic adenosine diphosphate-ribose (cADPR), and nicotinic acid adenine dinucleotide phosphate (NAADP+). In HIV-1-infected patients, increased CD38 expression on CD8+ T cells is linked to immune system activation and progression of HIV-1 infection. However, the role of CD38 upregulation in astrocyte function and HIV-1-associated dementia (HAD-now called HAND: HIV-1-associated neurocognitive disorder) neuropathogenesis is unclear. To these ends, we used interleukin (IL)-1beta and HIV-1gp120 to activate primary human astrocytes and measured CD38 expression using real-time polymerase chain reaction and CD38 function by ADP-ribosyl cyclase activity. We also determined cADPR-mediated changes in single-cell intracellular Ca(2+) transients in activated astrocytes in presence or absence of ethylene glycol tetraacetic acid. CD38 levels were downregulated using CD38 small-interfering RNA (siRNA) and intracellular Ca(2+) concentration ([Ca(2+)](i)) was measured. We previously reported a approximately 20-fold rise in CD38 messenger RNA levels in IL-1beta-activated astrocytes. We extend this observation and report that HIV-1gp120 potentiated CD38 expression in a dose-dependent manner and also increased CD38 enzyme activity in control and IL-1beta-activated astrocytes. We demonstrate higher cADPR levels in IL-1beta-activated astrocytes with a corresponding rise in [Ca(2+)](i) upon cADPR application and its non-hydrolysable analog, 3-deaza-cADPR. In activated astrocytes, pre-treatment with the cADPR-specific antagonist 8-Br-cADPR and CD38 siRNA transfection returned elevated [Ca(2+)](i) to baseline, thus confirming a CD38-cADPR specific response. These data are important for unraveling the mechanisms underlying the role of astrocyte-CD38 in HAD and have broader implications in other inflammatory diseases involving astrocyte activation and CD38 dysregulation.
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Affiliation(s)
- Sugato Banerjee
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
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94
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Miller DS, Bauer B, Hartz AMS. Modulation of P-glycoprotein at the blood-brain barrier: opportunities to improve central nervous system pharmacotherapy. Pharmacol Rev 2008; 60:196-209. [PMID: 18560012 DOI: 10.1124/pr.107.07109] [Citation(s) in RCA: 246] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Pharmacotherapy of central nervous system (CNS) disorders (e.g., neurodegenerative diseases, epilepsy, brain cancer, and neuro-AIDS) is limited by the blood-brain barrier. P-glycoprotein, an ATP-driven, drug efflux transporter, is a critical element of that barrier. High level of expression, luminal membrane location, multispecificity, and high transport potency make P-glycoprotein a selective gatekeeper of the blood-brain barrier and thus a primary obstacle to drug delivery into the brain. As such, P-glycoprotein limits entry into the CNS for a large number of prescribed drugs, contributes to the poor success rate of CNS drug candidates, and probably contributes to patient-to-patient variability in response to CNS pharmacotherapy. Modulating P-glycoprotein could therefore improve drug delivery into the brain. Here we review the current understanding of signaling mechanisms responsible for the modulation of P-glycoprotein activity/expression at the blood-brain barrier with an emphasis on recent studies from our laboratories. Using intact brain capillaries from rats and mice, we have identified multiple extracellular and intracellular signals that regulate this transporter; several signaling pathways have been mapped. Three pathways are triggered by elements of the brain's innate immune response, one by glutamate, one by xenobiotic-nuclear receptor (pregnane X receptor) interactions, and one by elevated beta-amyloid levels. Signaling is complex, with several pathways sharing common signaling elements [tumor necrosis factor (TNF) receptor 1, endothelin (ET) B receptor, protein kinase C, and nitric-oxide synthase), suggesting a regulatory network. Several pathways include autocrine/paracrine elements, involving release of the proinflammatory cytokine, TNF-alpha, and the polypeptide hormone, ET-1. Finally, several steps in signaling are potential therapeutic targets that could be used to modulate P-glycoprotein activity in the clinic.
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Affiliation(s)
- David S Miller
- Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA.
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95
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Chattopadhyay N, Zastre J, Wong HL, Wu XY, Bendayan R. Solid Lipid Nanoparticles Enhance the Delivery of the HIV Protease Inhibitor, Atazanavir, by a Human Brain Endothelial Cell Line. Pharm Res 2008; 25:2262-71. [DOI: 10.1007/s11095-008-9615-2] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2008] [Accepted: 04/28/2008] [Indexed: 11/24/2022]
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96
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Ronaldson PT, Bendayan R. HIV-1 viral envelope glycoprotein gp120 produces oxidative stress and regulates the functional expression of multidrug resistance protein-1 (Mrp1) in glial cells. J Neurochem 2008; 106:1298-313. [PMID: 18485102 DOI: 10.1111/j.1471-4159.2008.05479.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Brain human immunodeficiency virus type-1 (HIV-1) infection is associated with oxidative stress, which may lead to HIV-1 encephalitis, a chronic neurodegenerative condition. In vitro, oxidative stress can be induced in glial cells by exposure to HIV-1 envelope protein glycoprotein (gp120). Multidrug resistance proteins (Mrps) are known to efflux endogenous substrates (i.e. GSH and GSSG) involved in cellular defense against oxidative stress. Altered GSH/GSSG export may contribute to oxidative damage during HIV-1 encephalitis. At present, it is unknown if gp120 exposure can alter the functional expression of Mrp isoforms. Heat-shock protein 70, inducible nitric oxide synthase, intracellular GSSG, 2',7'-dichlorofluorescein fluorescence, and extracellular nitrite were increased in primary cultures of rat astrocytes triggered with gp120, suggesting an oxidative stress response. RT-PCR and immunoblot analysis demonstrated increased Mrp1 mRNA (2.3-fold) and protein (2.2-fold), respectively, in gp120 treated astrocytes while Mrp4 mRNA or protein expression was not changed. Cellular retention of 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein, an established Mrp substrate, was reduced (twofold) in gp120-treated astrocytes, suggesting increased Mrp-mediated transport. In addition, GSH and GSSG export were enhanced in gp120-triggered cells. These data suggest that gp120 can up-regulate Mrp1, but not Mrp4, functional expression in cultured astrocytes. Our observation of increased GSH/GSSG efflux in response to gp120 treatment implies that Mrp isoforms may be involved in regulating the oxidative stress response in glial cells.
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Affiliation(s)
- Patrick T Ronaldson
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario, Canada
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97
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Endothelin-1 Reduces P-Glycoprotein Transport Activity in an In Vitro Model of Human Adult Blood–brain Barrier. Cell Mol Neurobiol 2008; 28:915-21. [DOI: 10.1007/s10571-008-9277-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2008] [Accepted: 03/13/2008] [Indexed: 02/06/2023]
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98
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Visalli V, Muscoli C, Sacco I, Sculco F, Palma E, Costa N, Colica C, Rotiroti D, Mollace V. N-acetylcysteine prevents HIV gp 120-related damage of human cultured astrocytes: correlation with glutamine synthase dysfunction. BMC Neurosci 2007; 8:106. [PMID: 18062818 PMCID: PMC2221944 DOI: 10.1186/1471-2202-8-106] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2007] [Accepted: 12/06/2007] [Indexed: 12/22/2022] Open
Abstract
Background HIV envelope gp 120 glycoprotein is released during active HIV infection of brain macrophages thereby generating inflammation and oxidative stress which contribute to the development of the AIDS-Dementia Complex (ADC). Gp120 has also been found capable to generate excitotoxic effect on brain tissue via enhancement of glutamatergic neurotransmission, leading to neuronal and astroglial damage, though the mechanism is still to be better understood. Here we investigated on the effect of N-acetylcysteine (NAC), on gp120-induced damage in human cultured astroglial cells and the possible contribution of gp120-related reacting oxygen species (ROS) in the imbalanced activity of glutamine synthase (GS), the enzyme that metabolizes glutamate into glutamine within astroglial cells playing a neuroprotective role in brain disorders. Results Incubation of Lipari human cultured astroglial cells with gp 120 (0.1–10 nM) produced a significant reduction of astroglial cell viability and apoptosis as evaluated by TUNEL reaction and flow cytometric analysis (FACS). This effect was accompanied by lipid peroxidation as detected by means of malondialdehyde assay (MDA). In addition, gp 120 reduced both glutamine concentration in astroglial cell supernatants and GS expression as detected by immunocytochemistry and western blotting analysis. Pre-treatment of cells with NAC (0.5–5 mM), dose-dependently antagonised astroglial apoptotic cell death induced by gp 120, an effect accompanied by significant attenuation of MDA accumulation. Furthermore, both effects were closely associated with a significant recovery of glutamine levels in cell supernatants and by GS expression, thus suggesting that overproduction of free radicals might contribute in gp 120-related dysfunction of GS in astroglial cells. Conclusion In conclusion, the present experiments demonstrate that gp 120 is toxic to astroglial cells, an effect accompanied by lipid peroxidation and by altered glutamine release. All the effects of gp120 on astroglial cells were counteracted by NAC thus suggesting a novel and potentially useful approach in the treatment of glutammatergic disorders found in HAD patients.
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Affiliation(s)
- Valeria Visalli
- Department of Pharmacobiological Sciences, Faculty of Pharmacy, University Magna Graecia, Catanzaro, Italy.
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99
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Human immunodeficiency virus type 1 efficiently binds to human fetal astrocytes and induces neuroinflammatory responses independent of infection. BMC Neurosci 2007; 8:31. [PMID: 17498309 PMCID: PMC1884168 DOI: 10.1186/1471-2202-8-31] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Accepted: 05/12/2007] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND HIV-1 infects human astrocytes in vitro and in vivo but the frequency of infected cells is low and its biological significance is unknown. In studies in vitro, recombinant gp120 alone can induce profound effects on astrocyte biology, suggesting that HIV-1 interaction with astrocytes and its functional consequences extend beyond the limited levels of infection in these cells. Here we determined the relative efficiencies of HIV-1 binding and infection in human fetal astrocytes (HFA), mainly at the single cell level, using HIV-1 tagged with green fluorescence protein (GFP)-Vpr fusion proteins, termed HIV-GFP, to detect virus binding and HIV-1 expressing Rev and NefGFP fusion proteins to detect productive infection. RESULTS Essentially all HFA in a population bound HIV-GFP specifically and independently of CCR5 and CXCR4. The dynamics of this binding at 37 degrees C resembled binding of an HIV fusion mutant to CD4-positive cells, indicating that most of HIV-GFP arrested infection of HFA at the stage of virus-cell fusion. Despite extensive binding, only about 1% of HFA were detectably infected by HIV-RevGFP or HIV-NefGFP, but this proportion increased to the majority of HFA when the viruses were pseudotyped with vesicular stomatitis virus envelope glycoprotein G, confirming that HFA impose a restriction upon HIV-1 entry. Exposure of HFA to HIV-1 through its native proteins rapidly induced synthesis of interleukin-6 and interleukin-8 with increased mRNA detected within 3 h and increased protein detected within 18 h of exposure. CONCLUSION Our results indicate that HIV-1 binding to human astrocytes, although extensive, is not generally followed by virus entry and replication. Astrocytes respond to HIV-1 binding by rapidly increased cytokine production suggesting a role of this virus-brain cell interaction in HIV-1 neuropathogenesis.
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