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Santerre M, Wang Y, Arjona S, Allen C, Sawaya BE. Differential Contribution of HIV-1 Subtypes B and C to Neurological Disorders: Mechanisms and Possible Treatments. AIDS Rev 2019; 21:76-83. [PMID: 31332398 DOI: 10.24875/aidsrev.19000051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
With the introduction of combinatory antiretroviral therapy, patients infected with human immunodeficiency virus type 1 (HIV-1) can live much longer than before. However, the identification of HIV-associated neurocognitive disorder (HAND), especially HIV-associated dementia in 15-20% of patients infected with HIV-1, indicates additional complexity. These disorders turn out to be subtype dependent. Recently, many studies are ongoing trying to understand how the virus induces neuronal injury which could lead to neurological dysfunction. Most of these studies are focusing on the HIV-1 release of proteins such as Tat. However, the exact role of these proteins and their involvement in neuronal degeneration remains unidentified; this is especially true since viral proteins from different HIV-1 subtypes differ in their ability to cause neuronal damage. This review describes the role of different HIV-1 subtypes, identifies probable pathways involved in neuronal damage, the contribution of different HIV-1 subtypes to the progression of HAND, and potential treatments for HAND.
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Affiliation(s)
- Maryline Santerre
- Molecular Studies of Neurodegenerative Diseases Lab, FELS Institute for Cancer Research and Molecular Biology, Philadelphia, Pennsylvania, USA
| | - Ying Wang
- Molecular Studies of Neurodegenerative Diseases Lab, FELS Institute for Cancer Research and Molecular Biology, Philadelphia, Pennsylvania, USA
| | - Sterling Arjona
- Molecular Studies of Neurodegenerative Diseases Lab, FELS Institute for Cancer Research and Molecular Biology, Philadelphia, Pennsylvania, USA
| | - Charles Allen
- Molecular Studies of Neurodegenerative Diseases Lab, FELS Institute for Cancer Research and Molecular Biology, Philadelphia, Pennsylvania, USA
| | - Bassel E Sawaya
- Department of Neurology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
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2
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Yang L, Niu F, Yao H, Liao K, Chen X, Kook Y, Ma R, Hu G, Buch S. Exosomal miR-9 Released from HIV Tat Stimulated Astrocytes Mediates Microglial Migration. J Neuroimmune Pharmacol 2018; 13:330-344. [PMID: 29497921 DOI: 10.1007/s11481-018-9779-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 02/19/2018] [Indexed: 12/22/2022]
Abstract
Chronic neuroinflammation still remains a common underlying feature of HIV-infected patients on combined anti-retroviral therapy (cART). Previous studies have reported that despite near complete suppression of virus replication by cART, cytotoxic viral proteins such as HIV trans-activating regulatory protein (Tat) continue to persist in tissues such as the brain and the lymph nodes, thereby contributing, in part, to chronic glial activation observed in HIV-associated neurological disorders (HAND). Understanding how the glial cells cross talk to mediate neuropathology is thus of paramount importance. MicroRNAs (miR) also known as regulators of gene expression, have emerged as key paracrine signaling mediators that regulate disease pathogenesis and cellular crosstalk, through their transfer via the extracellular vesicles (EV). In the current study we have identified a novel function of miR-9, that of mediating microglial migration. We demonstrate that miR-9 released from Tat-stimulated astrocytes can be taken up by microglia resulting in their migratory phenotype. Exposure of human astrocytoma (A172) cells to HIV Tat resulted in induction and release of miR-9 in the EVs, which, was taken up by microglia, leading in turn, increased migration of the latter cells, a process that could be blocked by both an exosome inhibitor GW4869 or a specific target protector of miR-9. Furthermore, it was also demonstrated that EV miR-9 mediated inhibition of the expression of target PTEN, via its binding to the 3'UTR seed sequence of the PTEN mRNA, was critical for microglial migration. To validate the role of miR-9 in this process, microglial cells were treated with EVs loaded with miR-9, which resulted in significant downregulation of PTEN expression with a concomitant increase in microglial migration. These findings were corroborated by transfecting microglia with a specific target protector of PTEN, that blocked miR-9-mediated downregulation of PTEN as well as microglial migration. In vivo studies wherein the miR-9 precursor-transduced microglia were transplanted into the striatum of mice, followed by assessing their migration in response to a stimulus administered distally, further validated the role of miR-9 in mediating microglial migration. Collectively, our findings provide evidence that glial crosstalk via miRs released from EVs play a vital role in mediating disease pathogenesis and could provide new avenues for development of novel therapeutic strategies aimed at dampening neuropathogenesis.
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Affiliation(s)
- Lu Yang
- School of Medicine, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Fang Niu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Honghong Yao
- Department of Pharmacology, Medical School of Southeast University, Southeast University, Nanjing, China.,Key Laboratory of Developmental Genes and Human Disease, Southeast University, Institute of Life Sciences, Nanjing, China
| | - Ke Liao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Xufeng Chen
- The first Affiliated Hospital of Nanjing Medical University, Nanjing, 210029, China
| | - Yeonhee Kook
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Rong Ma
- Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, 430030, China
| | - Guoku Hu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA.
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3
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Wen X, Yan J, Han XR, Zheng GH, Tang R, Liu LF, Wu DM, Lu J, Zheng YL. PTEN gene silencing contributes to airway remodeling and induces airway smooth muscle cell proliferation in mice with allergic asthma. J Thorac Dis 2018; 10:202-211. [PMID: 29600050 DOI: 10.21037/jtd.2017.12.104] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background Allergic asthma is a complex genetic disorder that involves interactions between genetic and environmental factors. Usage of PTEN may be a good therapeutic strategy for the management of allergic inflammation. Thus, the present study aims to explore the effects of phosphatase and tensin homolog (PTEN) gene silencing on airway remodeling and proliferation of airway smooth muscle cells (ASMCs) in a mouse model of allergic asthma. Methods A total of 56 healthy female BABL/c mice (weighing between 16 to 22 grams) were selected and were assigned on random into ovalbumin (OVA; mice were stimulated with OVA to induce allergic asthma), OVA + si-PTEN, normal saline (NS; mice were treated with normal saline) and NS + si-PTEN groups. Masson staining was employed in order to observe lung tissue sections. Immunohistochemical staining was used to detect the expression of α-SMA+. Gene silencing was conducted in the NS + si-PTEN and OVA + si-PTEN groups. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) and western blotting were used to detect the mRNA and protein expressions of PTEN in ASMCs of each group. CCK-8 assay and flow cytometry were performed to determine the cell proliferation rate and cell cycle. Results Airway remodeling and changes of smooth muscle layer were found in allergic asthmatic mice with thick airway walls. The expression of alpha smooth muscle actin (α-SMA+) was significantly higher in ASMCs of the OVA, OVA + si-PTEN and NS + si-PTEN groups compared with ASMCs of the NS group. The mRNA and protein expressions of PTEN reduced in the OVA, OVA + si-PTEN and NS + si-PTEN groups. The rate of ASMCs proliferation in OVA, OVA + si-PTEN and NS + si-PTEN groups were significantly higher than the NS group. The proportion of ASMCs in S and G2 stages increased, while the number of cells in the G1 stage decreased after PTEN gene silencing. Conclusions These results demonstrated that PTEN gene silencing might promote proliferation of ASMCs and airway remodeling in a mouse model of allergic asthma.
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Affiliation(s)
- Xin Wen
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, Xuzhou 221116, China.,College of Health Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Jing Yan
- Emergency Center, the Affiliated Hospital of Xuzhou Medical University, Xuzhou 221009, China
| | - Xin-Rui Han
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, Xuzhou 221116, China.,College of Health Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Gui-Hong Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, Xuzhou 221116, China.,College of Health Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Ran Tang
- Department of Respiratory Medicine, The First Affiliated Hospital, Zhejiang University, Hangzhou 310003, China
| | - Li-Fang Liu
- Department of Respiratory Medicine, The First Affiliated Hospital, Zhejiang University, Hangzhou 310003, China
| | - Dong-Mei Wu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, Xuzhou 221116, China.,College of Health Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Jun Lu
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, Xuzhou 221116, China.,College of Health Sciences, Jiangsu Normal University, Xuzhou 221116, China
| | - Yuan-Lin Zheng
- Key Laboratory for Biotechnology on Medicinal Plants of Jiangsu Province, School of Life Science, Jiangsu Normal University, Xuzhou 221116, China.,College of Health Sciences, Jiangsu Normal University, Xuzhou 221116, China
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Pulido R. PTEN: a yin-yang master regulator protein in health and disease. Methods 2016; 77-78:3-10. [PMID: 25843297 DOI: 10.1016/j.ymeth.2015.02.009] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 02/19/2015] [Indexed: 01/16/2023] Open
Abstract
The PTEN gene is a tumor suppressor gene frequently mutated in human tumors, which encodes a ubiquitous protein whose major activity is to act as a lipid phosphatase that counteracts the action of the oncogenic PI3K. In addition, PTEN displays protein phosphatase- and catalytically-independent activities. The physiologic control of PTEN function, and its inactivation in cancer and other human diseases, including some neurodevelopmental disorders, is upon the action of multiple regulatory mechanisms. This provides a wide spectrum of potential therapeutic approaches to reconstitute PTEN activity. By contrast, inhibition of PTEN function may be beneficial in a different group of human diseases, such as type 2 diabetes or neuroregeneration-related pathologies. This makes PTEN a functionally dual yin-yang protein with high potential in the clinics. Here, a brief overview on PTEN and its relation with human disease is presented.
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Affiliation(s)
- Rafael Pulido
- BioCruces Health Research Institute, Barakaldo, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain.
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5
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Masvekar RR, El-Hage N, Hauser KF, Knapp PE. GSK3β-activation is a point of convergence for HIV-1 and opiate-mediated interactive neurotoxicity. Mol Cell Neurosci 2015; 65:11-20. [PMID: 25616162 DOI: 10.1016/j.mcn.2015.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2014] [Revised: 12/22/2014] [Accepted: 01/19/2015] [Indexed: 01/03/2023] Open
Abstract
Infection of the CNS with HIV-1 occurs rapidly after primary peripheral infection. HIV-1 can induce a wide range of neurological deficits, collectively known as HIV-1-associated neurocognitive disorders. Our previous work has shown that the selected neurotoxic effects induced by individual viral proteins, Tat and gp120, and by HIV(+) supernatant are enhanced by co-exposure to morphine. This mimics co-morbid neurological effects observed in opiate-abusing HIV(+) patients. Although there is a correlation between opiate drug abuse and progression of HIV-1-associated neurocognitive disorders, the mechanisms underlying interactions between HIV-1 and opiates remain obscure. Previous studies have shown that HIV-1 induces neurotoxic effects through abnormal activation of GSK3β. Interestingly, expression of GSK3β has shown to be elevated in brains of young opiate abusers indicating that GSK3β is also linked to neuropathology seen with opiate-abusing patients. Thus, we hypothesize that GSK3β activation is a point of convergence for HIV- and opiate-mediated interactive neurotoxic effects. Neuronal cultures were treated with supernatant from HIV-1SF162-infected THP-1 cells, in the presence or absence of morphine and GSK3β inhibitors. Our results show that GSK3β inhibitors, including valproate and small molecule inhibitors, significantly reduce HIV-1-mediated neurotoxic outcomes, and also negate interactions with morphine that result in cell death, suggesting that GSK3β-activation is an important point of convergence and a potential therapeutic target for HIV- and opiate-mediated neurocognitive deficits.
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Affiliation(s)
- Ruturaj R Masvekar
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Nazira El-Hage
- Department of Pharmacology and Toxicology, 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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6
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Abstract
The implementation of new antiretroviral therapies targeting transcription of early viral proteins in postintegrated HIV-1 can aid in overcoming current therapy limitations. Using high-throughput screening assays, we have previously described a novel Tat-dependent HIV-1 transcriptional inhibitor named 6-bromoindirubin-3'-oxime (6BIO). The screening of 6BIO derivatives yielded unique compounds that show potent inhibition of HIV-1 transcription. We have identified a second-generation derivative called 18BIOder as an inhibitor of HIV-1 Tat-dependent transcription in TZM-bl cells and a potent inhibitor of GSK-3β kinase in vitro. Structurally, 18BIOder is half the molecular weight and structure of its parental compound, 6BIO. More importantly, we also have found a different GSK-3β complex present only in HIV-1-infected cells. 18BIOder preferentially inhibits this novel kinase complex from infected cells at nanomolar concentrations. Finally, we observed that neuronal cultures treated with Tat protein are protected from Tat-mediated cytotoxicity when treated with 18BIOder. Overall, our data suggest that HIV-1 Tat-dependent transcription is sensitive to small-molecule inhibition of GSK-3β.
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7
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Narayanan A, Iordanskiy S, Das R, Van Duyne R, Santos S, Jaworski E, Guendel I, Sampey G, Dalby E, Iglesias-Ussel M, Popratiloff A, Hakami R, Kehn-Hall K, Young M, Subra C, Gilbert C, Bailey C, Romerio F, Kashanchi F. Exosomes derived from HIV-1-infected cells contain trans-activation response element RNA. J Biol Chem 2013; 288:20014-33. [PMID: 23661700 PMCID: PMC3707700 DOI: 10.1074/jbc.m112.438895] [Citation(s) in RCA: 234] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2012] [Revised: 05/03/2013] [Indexed: 12/20/2022] Open
Abstract
Exosomes are nano-sized vesicles produced by healthy and virus-infected cells. Exosomes derived from infected cells have been shown to contain viral microRNAs (miRNAs). HIV-1 encodes its own miRNAs that regulate viral and host gene expression. The most abundant HIV-1-derived miRNA, first reported by us and later by others using deep sequencing, is the trans-activation response element (TAR) miRNA. In this study, we demonstrate the presence of TAR RNA in exosomes from cell culture supernatants of HIV-1-infected cells and patient sera. TAR miRNA was not in Ago2 complexes outside the exosomes but enclosed within the exosomes. We detected the host miRNA machinery proteins Dicer and Drosha in exosomes from infected cells. We report that transport of TAR RNA from the nucleus into exosomes is a CRM1 (chromosome region maintenance 1)-dependent active process. Prior exposure of naive cells to exosomes from infected cells increased susceptibility of the recipient cells to HIV-1 infection. Exosomal TAR RNA down-regulated apoptosis by lowering Bim and Cdk9 proteins in recipient cells. We found 10(4)-10(6) copies/ml TAR RNA in exosomes derived from infected culture supernatants and 10(3) copies/ml TAR RNA in the serum exosomes of highly active antiretroviral therapy-treated patients or long term nonprogressors. Taken together, our experiments demonstrated that HIV-1-infected cells produced exosomes that are uniquely characterized by their proteomic and RNA profiles that may contribute to disease pathology in AIDS.
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Affiliation(s)
- Aarthi Narayanan
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Sergey Iordanskiy
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
- the Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington D. C. 20037
| | - Ravi Das
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Rachel Van Duyne
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
- the Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington D. C. 20037
| | - Steven Santos
- the Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington D. C. 20037
| | - Elizabeth Jaworski
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Irene Guendel
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Gavin Sampey
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Elizabeth Dalby
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Maria Iglesias-Ussel
- the Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Anastas Popratiloff
- the Department of Microbiology, Immunology and Tropical Medicine, George Washington University, Washington D. C. 20037
| | - Ramin Hakami
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Kylene Kehn-Hall
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Mary Young
- the Washington Metropolitan Women's Interagency HIV Study, Division of Infectious Diseases, Georgetown University Medical Center, Washington, D. C. 20007, and
| | - Caroline Subra
- the Department of Microbiology, Infectiology, and Immunology, Medicine Faculty, Laval University Center Hospitalier Universitaire de Quebec Research Center, City of Quebec, Quebec G1R2J6, Canada
| | - Caroline Gilbert
- the Department of Microbiology, Infectiology, and Immunology, Medicine Faculty, Laval University Center Hospitalier Universitaire de Quebec Research Center, City of Quebec, Quebec G1R2J6, Canada
| | - Charles Bailey
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
| | - Fabio Romerio
- the Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Fatah Kashanchi
- From the National Center for Biodefense and Infectious Diseases, George Mason University, Manassas, Virginia 20110
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8
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Kreiner G, Bierhoff H, Armentano M, Rodriguez-Parkitna J, Sowodniok K, Naranjo JR, Bonfanti L, Liss B, Schütz G, Grummt I, Parlato R. A neuroprotective phase precedes striatal degeneration upon nucleolar stress. Cell Death Differ 2013; 20:1455-64. [PMID: 23764776 PMCID: PMC3792439 DOI: 10.1038/cdd.2013.66] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Revised: 05/03/2013] [Accepted: 05/16/2013] [Indexed: 01/17/2023] Open
Abstract
The nucleolus is implicated in sensing and responding to cellular stress by stabilizing p53. The pro-apoptotic effect of p53 is associated with several neurodegenerative disorders, including Huntington's disease (HD), which is characterized by the progressive loss of medium spiny neurons (MSNs) in the striatum. Here we show that disruption of nucleolar integrity and function causes nucleolar stress and is an early event in MSNs of R6/2 mice, a transgenic model of HD. Targeted perturbation of nucleolar function in MSNs by conditional knockout of the RNA polymerase I-specific transcription initiation factor IA (TIF-IA) leads to late progressive striatal degeneration, HD-like motor abnormalities and molecular signatures. Significantly, p53 prolongs neuronal survival in TIF-IA-deficient MSNs by transient upregulation of phosphatase and tensin homolog deleted on chromosome 10 (PTEN), a tumor suppressor that inhibits mammalian target of rapamycin signaling and induces autophagy. The results emphasize the initial role of nucleolar stress in neurodegeneration and uncover a p53/PTEN-dependent neuroprotective response.
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Affiliation(s)
- G Kreiner
- 1] Department of Molecular Biology of the Cell I, DKFZ-ZMBH Alliance, German Cancer Research Center, Heidelberg, Germany [2] Department of Brain Biochemistry, Institute of Pharmacology, Polish Academy of Sciences, Cracow, Poland
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9
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Hauser KF, Fitting S, Dever SM, Podhaizer EM, Knapp PE. Opiate drug use and the pathophysiology of neuroAIDS. Curr HIV Res 2012; 10:435-52. [PMID: 22591368 PMCID: PMC3431547 DOI: 10.2174/157016212802138779] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2011] [Revised: 01/12/2012] [Accepted: 01/14/2012] [Indexed: 11/22/2022]
Abstract
Opiate abuse and HIV-1 have been described as interrelated epidemics, and even in the advent of combined anti-retroviral therapy, the additional abuse of opiates appears to result in greater neurologic and cognitive deficits. The central nervous system (CNS) is particularly vulnerable to interactive opiate-HIV-1 effects, in part because of the unique responses of microglia and astroglia. Although neurons are principally responsible for behavior and cognition, HIV-1 infection and replication in the brain is largely limited to microglia, while astroglia and perhaps glial progenitors can be latently infected. Thus, neuronal dysfunction and injury result from cellular and viral toxins originating from HIV-1 infected/exposed glia. Importantly, subsets of glial cells including oligodendrocytes, as well as neurons, express µ-opioid receptors and therefore can be direct targets for heroin and morphine (the major metabolite of heroin in the CNS), which preferentially activate µ-opioid receptors. This review highlights findings that neuroAIDS is a glially driven disease, and that opiate abuse may act at multiple glial-cell types to further compromise neuron function and survival. The ongoing, reactive cross-talk between opiate drug and HIV-1 co-exposed microglia and astroglia appears to exacerbate critical proinflammatory and excitotoxic events leading to neuron dysfunction, injury, and potentially death. Opiates enhance synaptodendritic damage and a loss of synaptic connectivity, which is viewed as the substrate of cognitive deficits. We especially emphasize that opioid signaling and interactions with HIV-1 are contextual, differing among cell types, and even within subsets of the same cell type. For example, astroglia even within a single brain region are heterogeneous in their expression of µ-, δ-, and κ-opioid receptors, as well as CXCR4 and CCR5, and Toll-like receptors. Thus, defining the distinct targets engaged by opiates in each cell type, and among brain regions, is critical to an understanding of how opiate abuse exacerbates neuroAIDS.
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Affiliation(s)
- Kurt F Hauser
- Department of Pharmacology and Toxicology, 1217 East Marshall Street, Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298, USA.
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10
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Podhaizer EM, Zou S, Fitting S, Samano KL, El-Hage N, Knapp PE, Hauser KF. Morphine and gp120 toxic interactions in striatal neurons are dependent on HIV-1 strain. J Neuroimmune Pharmacol 2011; 7:877-91. [PMID: 22101471 DOI: 10.1007/s11481-011-9326-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Accepted: 11/04/2011] [Indexed: 11/30/2022]
Abstract
A rigorously controlled, cell culture paradigm was used to assess the role of HIV-1 gp120 ± morphine in mediating opioid-HIV interactive toxicity in striatal neurons. Computerized time-lapse microscopy tracked the fate of individual neurons co-cultured with mixed-glia from mouse striata during opioid and gp120 exposure. Subpopulations of neurons and astroglia displayed μ-opioid receptor, CXCR4, and CCR5 immunoreactivity. While gp120 alone was or tended to be neurotoxic irrespective of whether X4-tropic gp120(IIIB), R5-tropic gp120(ADA), or dual-tropic gp120(MN) was administered, interactive toxicity with morphine differed depending on HIV-1 strain. For example, morphine only transiently exacerbated gp120(IIIB)-induced neuronal death; however, in combination with gp120(MN), morphine caused sustained increases in the rate of neuronal death compared to gp120(MN) alone that were prevented by naloxone. Alternatively, gp120(ADA) significantly increased the rate of neuron death, but gp120(ADA) toxicity was unaffected by morphine. The transient neurotoxic interactions between morphine and gp120(IIIB) were abrogated in the absence of glia suggesting that glia contribute significantly to the interactive pathology with chronic opiate abuse and neuroAIDS. To assess how mixed-glia might contribute to the neurotoxicity, the effects of morphine and/or gp120 on the production of reactive oxygen species (ROS) and on glutamate buffering were examined. All gp120 variants, and to a lesser extent morphine, increased ROS and/or decreased glutamate buffering, but together failed to show any interaction with morphine. Our findings indicate that HIV-1 strain-specific differences in gp120 are critical determinants in shaping both the timing and pattern of neurotoxic interactions with opioid drugs.
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Affiliation(s)
- Elizabeth M Podhaizer
- Department of Pharmacology & Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298-0613, USA
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11
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Suzuki M, El-Hage N, Zou S, Hahn YK, Sorrell ME, Sturgill JL, Conrad DH, Knapp PE, Hauser KF. Fractalkine/CX3CL1 protects striatal neurons from synergistic morphine and HIV-1 Tat-induced dendritic losses and death. Mol Neurodegener 2011; 6:78. [PMID: 22093090 PMCID: PMC3287119 DOI: 10.1186/1750-1326-6-78] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 11/17/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Fractalkine/CX3CL1 and its cognate receptor CX3CR1 are abundantly expressed in the CNS. Fractalkine is an unusual C-X3-C motif chemokine that is important in neuron-microglial communication, a co-receptor for HIV infection, and can be neuroprotective. To assess the effects of fractalkine on opiate-HIV interactive neurotoxicity, wild-type murine striatal neurons were co-cultured with mixed glia from the striata of wild-type or Cx3cr1 knockout mice ± HIV-1 Tat and/or morphine. Time-lapse digital images were continuously recorded at 20 min intervals for up to 72 h using computer-aided microscopy to track the same cells repeatedly. RESULTS Co-exposure to Tat and morphine caused synergistic increases in neuron death, dendritic pruning, and microglial motility as previously reported. Exogenous fractalkine prevented synergistic Tat and morphine-induced dendritic losses and neuron death even though the inflammatory mediator TNF-α remained significantly elevated. Antibody blockade of CX3CR1 mimicked the toxic effects of morphine plus Tat, but did not add to their toxicity; while fractalkine failed to protect wild-type neurons co-cultured with Cx3cr1-/--null glia against morphine and Tat toxicity. Exogenous fractalkine also normalized microglial motility, which is elevated by Tat and morphine co-exposure, presumably limiting microglial surveillance that may lead to toxic effects on neurons. Fractalkine immunofluorescence was expressed in neurons and to a lesser extent by other cell types, whereas CX3CR1 immunoreactivity or GFP fluorescence in cells cultured from the striatum of Cx3cr1-/- (Cx3cr1GFP/GFP) mice were associated with microglia. Immunoblotting shows that fractalkine levels were unchanged following Tat and/or morphine exposure and there was no increase in released fractalkine as determined by ELISA. By contrast, CX3CR1 protein levels were markedly downregulated. CONCLUSIONS The results suggest that deficits in fractalkine-CX3CR1 signaling contribute to the synergistic neurotoxic effects of opioids and Tat. Importantly, exogenous fractalkine can selectively protect neurons from the injurious effects of chronic opioid-HIV-1 Tat co-exposure, and this suggests a potential therapeutic course for neuroAIDS. Although the cellular mechanisms underlying neuroprotection are not certain, findings that exogenous fractalkine reduces microglial motility and fails to protect neurons co-cultured with Cx3cr1-/- mixed glia suggest that fractalkine may act by interfering with toxic microglial-neuron interactions.
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Affiliation(s)
- Masami Suzuki
- Department of Pharmacology and Toxicology, Virginia Commonwealth University School of Medicine, Richmond, VA 23298-0613, USA
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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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