1
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Schenck JK, Karl MT, Clarkson-Paredes C, Bastin A, Pushkarsky T, Brichacek B, Miller RH, Bukrinsky MI. Extracellular vesicles produced by HIV-1 Nef-expressing cells induce myelin impairment and oligodendrocyte damage in the mouse central nervous system. J Neuroinflammation 2024; 21:127. [PMID: 38741181 PMCID: PMC11090814 DOI: 10.1186/s12974-024-03124-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 05/04/2024] [Indexed: 05/16/2024] Open
Abstract
HIV-associated neurocognitive disorders (HAND) are a spectrum of cognitive impairments that continue to affect approximately half of all HIV-positive individuals despite effective viral suppression through antiretroviral therapy (ART). White matter pathologies have persisted in the ART era, and the degree of white matter damage correlates with the degree of neurocognitive impairment in patients with HAND. The HIV protein Nef has been implicated in HAND pathogenesis, but its effect on white matter damage has not been well characterized. Here, utilizing in vivo, ex vivo, and in vitro methods, we demonstrate that Nef-containing extracellular vesicles (Nef EVs) disrupt myelin sheaths and inflict damage upon oligodendrocytes within the murine central nervous system. Intracranial injection of Nef EVs leads to reduced myelin basic protein (MBP) staining and a decreased number of CC1 + oligodendrocytes in the corpus callosum. Moreover, cerebellar slice cultures treated with Nef EVs exhibit diminished MBP expression and increased presence of unmyelinated axons. Primary mixed brain cultures and enriched oligodendrocyte precursor cell cultures exposed to Nef EVs display a decreased number of O4 + cells, indicative of oligodendrocyte impairment. These findings underscore the potential contribution of Nef EV-mediated damage to oligodendrocytes and myelin maintenance in the pathogenesis of HAND.
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Affiliation(s)
- Jessica K Schenck
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA
| | - Molly T Karl
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA
| | - Cheryl Clarkson-Paredes
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA
| | - Ashley Bastin
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA
| | - Tatiana Pushkarsky
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA
| | - Beda Brichacek
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA
| | - Robert H Miller
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA
| | - Michael I Bukrinsky
- School of Medicine and Health Sciences, The George Washington University, 2300 I St NW, Ross Hall 624, Washington, DC, 20037, USA.
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2
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Killingsworth L, Spudich S. Neuropathogenesis of HIV-1: insights from across the spectrum of acute through long-term treated infection. Semin Immunopathol 2022; 44:709-724. [PMID: 35882661 PMCID: PMC10126949 DOI: 10.1007/s00281-022-00953-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 05/20/2022] [Indexed: 01/16/2023]
Abstract
This review outlines the neuropathogenesis of HIV, from initial HIV entry into the central nervous system (CNS) to chronic infection, focusing on key advancements in the last 5 years. Discoveries regarding acute HIV infection reveal timing and mechanisms of early HIV entry and replication in the CNS, early inflammatory responses, and establishment of genetically distinct viral reservoirs in the brain. Recent studies additionally explore how chronic HIV infection is maintained in the CNS, examining how the virus remains in a latent "hidden" state in diverse cells in the brain, and how this leads to sustained pathological inflammatory responses. Despite viral suppression with antiretroviral therapy, HIV can persist and even replicate in the CNS, and associate with ongoing neuropathology including CD8 + T-lymphocyte mediated encephalitis. Crucial investigation to advance our understanding of the immune mechanisms that both control viral infection and lead to pathological consequences in the brain is necessary to develop treatments to optimize long-term neurologic health in people living with HIV.
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Affiliation(s)
- Lauren Killingsworth
- Department of Neurology, Yale University School of Medicine, 300 George Street, Room 8300c, New Haven, CT, 06520, USA
| | - Serena Spudich
- Department of Neurology, Yale University School of Medicine, 300 George Street, Room 8300c, New Haven, CT, 06520, USA.
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3
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Brain PET Imaging: Value for Understanding the Pathophysiology of HIV-associated Neurocognitive Disorder (HAND). Curr HIV/AIDS Rep 2020; 16:66-75. [PMID: 30778853 DOI: 10.1007/s11904-019-00419-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW The purpose of this review is to summarize recent developments in PET imaging of neuropathologies underlying HIV-associated neurocognitive dysfunction (HAND). We concentrate on the recent post antiretroviral era (ART), highlighting clinical and preclinical brain PET imaging studies. RECENT FINDINGS In the post ART era, PET imaging has been used to better understand perturbations of glucose metabolism, neuroinflammation, the function of neurotransmitter systems, and amyloid/tau protein deposition in the brains of HIV-infected patients and HIV animal models. Preclinical and translational findings from those studies shed a new light on the complex pathophysiology underlying HAND. The molecular imaging capabilities of PET in neuro-HIV are great complements for structural imaging modalities. Recent and future PET imaging studies can improve our understanding of neuro-HIV and provide biomarkers of disease progress that could be used as surrogate endpoints in the evaluation of the effectiveness of potential neuroprotective therapies.
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4
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Morrey JD, Oliveira ALR, Wang H, Zukor K, de Castro MV, Siddharthan V. Zika virus infection causes temporary paralysis in adult mice with motor neuron synaptic retraction and evidence for proximal peripheral neuropathy. Sci Rep 2019; 9:19531. [PMID: 31862897 PMCID: PMC6925114 DOI: 10.1038/s41598-019-55717-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/01/2019] [Indexed: 12/27/2022] Open
Abstract
Clinical evidence is mounting that Zika virus can contribute to Guillain-Barré syndrome which causes temporary paralysis, yet the mechanism is unknown. We investigated the mechanism of temporary acute flaccid paralysis caused by Zika virus infection in aged interferon αβ-receptor knockout mice used for their susceptibility to infection. Twenty-five to thirty-five percent of mice infected subcutaneously with Zika virus developed motor deficits including acute flaccid paralysis that peaked 8-10 days after viral challenge. These mice recovered within a week. Despite Zika virus infection in the spinal cord, motor neurons were not destroyed. We examined ultrastructures of motor neurons and synapses by transmission electron microscopy. The percent coverage of motor neurons by boutons was reduced by 20%; more specifically, flattened-vesicle boutons were reduced by 46%, and were normalized in recovering mice. Using electromyographic procedures employed in people to help diagnose Guillain-Barré syndrome, we determined that nerve conduction velocities between the sciatic notch and the gastrocnemius muscle were unchanged in paralyzed mice. However, F-wave latencies were increased in paralyzed mice, which suggests that neuropathy may exist between the sciatic notch to the nerve rootlets. Reversible synaptic retraction may be a previously unrecognized cofactor along with peripheral neuropathy for the development of Guillain-Barré syndrome during Zika virus outbreaks.
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Affiliation(s)
- John D Morrey
- Institute for Antiviral Research, Department of Animal, Dairy, and Veterinary Sciences, 5600 Old Main Hill, Utah State University, Logan, Utah, 84322-5600, United States of America.
| | | | - Hong Wang
- Institute for Antiviral Research, Department of Animal, Dairy, and Veterinary Sciences, 5600 Old Main Hill, Utah State University, Logan, Utah, 84322-5600, United States of America
| | - Katherine Zukor
- Institute for Antiviral Research, Department of Animal, Dairy, and Veterinary Sciences, 5600 Old Main Hill, Utah State University, Logan, Utah, 84322-5600, United States of America
| | | | - Venkatraman Siddharthan
- Institute for Antiviral Research, Department of Animal, Dairy, and Veterinary Sciences, 5600 Old Main Hill, Utah State University, Logan, Utah, 84322-5600, United States of America
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5
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Delery EC, MacLean AG. Culture Model for Non-human Primate Choroid Plexus. Front Cell Neurosci 2019; 13:396. [PMID: 31555096 PMCID: PMC6724611 DOI: 10.3389/fncel.2019.00396] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/15/2019] [Indexed: 11/13/2022] Open
Abstract
While there are murine and rat choroid plexus epithelial cell cultures, a translationally relevant model for choroid plexus activation and function is still lacking. The rhesus macaque is the gold standard for modeling viral infection and activation of CNS, including HIV-associated neurocognitive disorders. We have developed a rhesus macaque choroid plexus epithelial cell culture model which we believe to be suitable for studies of inflammation associated with viral infection of the CNS. Epithelial morphology and function were assessed using vimentin, phalloidin, the tight junction protein zonula-occludens-1 (ZO-1), and focal adhesion kinase (FAK). Choroid plexus epithelial cell type was confirmed using immunofluorescence with two proteins highly expressed in the choroid plexus: transthyretin and α-klotho. Finally, barrier properties of the model were monitored using pro- and anti-inflammatory mediators (TNF-α, the TLR2 agonist PamCys3K, and dexamethasone). When pro-inflammatory TNF-α was added to the xCelligence wells, there was a decrease in barrier function, which decreased in a step-wise fashion with each additional administration. This barrier function was repaired upon addition of the steroid dexamethasone. The TLR2 agonist PAM3CysK increased barrier functions in TNF-α treated wells. We have presented a model of the blood-CSF barrier that will allow study into pro- and anti-inflammatory conditions in the brain, while simultaneously measuring real time changes to epithelial cells.
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Affiliation(s)
- Elizabeth C Delery
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA, United States.,Tulane Program in Biomedical Sciences, New Orleans, LA, United States.,Department of Microbiology and Immunology, Tulane Medical School, New Orleans, LA, United States
| | - Andrew G MacLean
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA, United States.,Tulane Program in Biomedical Sciences, New Orleans, LA, United States.,Department of Microbiology and Immunology, Tulane Medical School, New Orleans, LA, United States.,Tulane Brain Institute, New Orleans, LA, United States.,Tulane Center for Aging, New Orleans, LA, United States
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6
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Hu G, Niu F, Liao K, Periyasamy P, Sil S, Liu J, Dravid SM, Buch S. HIV-1 Tat-Induced Astrocytic Extracellular Vesicle miR-7 Impairs Synaptic Architecture. J Neuroimmune Pharmacol 2019; 15:538-553. [PMID: 31401755 PMCID: PMC7008083 DOI: 10.1007/s11481-019-09869-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Accepted: 07/28/2019] [Indexed: 12/20/2022]
Abstract
Although combination antiretroviral therapy (cART) has improved the health of millions of those living with HIV-1 (Human Immunodeficiency Virus, Type 1), the penetration into the central nervous system (CNS) of many such therapies is limited, thereby resulting in residual neurocognitive impairment commonly referred to as NeuroHIV. Additionally, while cART has successfully suppressed peripheral viremia, cytotoxicity associated with the presence of viral Transactivator of transcription (Tat) protein in tissues such as the brain, remains a significant concern. Our previous study has demonstrated that both HIV-1 Tat as well as opiates such as morphine, can directly induce synaptic alterations via independent pathways. Herein, we demonstrate that exposure of astrocytes to HIV-1 protein Tat mediates the induction and release of extracellular vesicle (EV) microRNA-7 (miR-7) that is taken up by neurons, leading in turn, to downregulation of neuronal neuroligin 2 (NLGN2) and ultimately to synaptic alterations. More importantly, we report that these impairments could be reversed by pretreatment of neurons with a neurotrophic factor platelet-derived growth factor-CC (PDGF-CC). Graphical Abstract ![]()
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Affiliation(s)
- Guoku Hu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA.
| | - Fang Niu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Ke Liao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Palsamy Periyasamy
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Susmita Sil
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA
| | - Jinxu Liu
- Department of Pharmacology, Creighton University, Omaha, NE, USA
| | | | - Shilpa Buch
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE, USA.
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7
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Chiu KB, Lee KM, Robillard KN, MacLean AG. A Method to Investigate Astrocyte and Microglial Morphological Changes in the Aging Brain of the Rhesus Macaque. Methods Mol Biol 2019; 1938:265-276. [PMID: 30617987 DOI: 10.1007/978-1-4939-9068-9_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
With a rapidly aging population, studies of neuroinflammation and degeneration associated with eugeric aging are becoming critical. Using the unique archive at the Tulane National Primate Research Center as a resource, we have developed tools to quantify morphological changes in astrocytes and microglia across the life span of monkeys. This method can be used for morphometric studies of multiple parameters simultaneously in an unbiased manner.
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Affiliation(s)
- Kevin B Chiu
- Tulane National Primate Research Center, Covington, LA, USA.,Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | - Kim M Lee
- Tulane National Primate Research Center, Covington, LA, USA.,Vanderbilt Hospital Nashville, Nashville, TN, USA.,Tulane Program in Biomedical Sciences, Tulane University School of Medicine, New Orleans, LA, USA
| | - Katelyn N Robillard
- Tulane National Primate Research Center, Covington, LA, USA.,Neuroscience Center of Excellence, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | - Andrew G MacLean
- Tulane National Primate Research Center, Covington, LA, USA. .,Tulane Program in Biomedical Sciences, Tulane University School of Medicine, New Orleans, LA, USA. .,Tulane Brain Institute, Tulane University, New Orleans, LA, USA. .,Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, USA.
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8
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Ramsey J, Martin EC, Purcell OM, Lee KM, MacLean AG. Self-injurious behaviours in rhesus macaques: Potential glial mechanisms. JOURNAL OF INTELLECTUAL DISABILITY RESEARCH : JIDR 2018; 62:1008-1017. [PMID: 30450801 PMCID: PMC6385863 DOI: 10.1111/jir.12558] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/20/2018] [Accepted: 09/28/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Self-injurious behaviour (SIB) can be classified as intentional, direct injuring of body tissue usually without suicidal intent. In its non-suicidal form it is commonly seen as a clinical sign of borderline personality disorder, autism, PTSD, depression, and anxiety affecting a wide range of ages and conditions. In rhesus macaques SIB is most commonly manifested through hair plucking, self-biting, self-hitting, and head banging. SIB in the form of self-biting is observed in approximately 5-15% of individually housed monkeys. Recently, glial cells are becoming recognised as key players in regulating behaviours. METHOD The goal of this study was to determine the role of glial activation, including astrocytes, in macaques that had displayed SIB. To this end, we performed immunohistochemistry and next generation sequence of brain tissues from rhesus macaques with SIB. RESULTS Our studies showed increased vimentin, but not nestin, expression on astrocytes of macaques displaying SIB. Initial RNA Seq analyses indicate activation of pathways involved in tissue remodelling, neuroinflammation and cAMP signalling. CONCLUSIONS Glia are most probably activated in primates with self-injury, and are therefore potential novel targets for therapeutics.
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Affiliation(s)
- Joseph Ramsey
- Tulane Program in Neuroscience, Tulane University, New Orleans, LA 70112
| | - Elizabeth C. Martin
- Center for Stem Cell Research and Regenerative Medicine, School of Medicine, Tulane University, New Orleans, LA 70112
| | - Olivia M. Purcell
- Tulane Program in Neuroscience, Tulane University, New Orleans, LA 70112
| | - Kim M. Lee
- Tulane National Primate Research Center, Covington, LA 70433
- Tulane Program in Biomedical Science, Tulane Medical School, New Orleans, LA 70112
| | - Andrew G. MacLean
- Tulane Program in Neuroscience, Tulane University, New Orleans, LA 70112
- Tulane National Primate Research Center, Covington, LA 70433
- Tulane Program in Biomedical Science, Tulane Medical School, New Orleans, LA 70112
- Department of Microbiology & Immunology, Tulane Medical School, New Orleans, LA 70112
- Tulane Center for Aging, Tulane University New Orleans, LA 70112
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9
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Abstract
Viral infection in the brain can be acute or chronic, with the responses often producing foci of increasingly cytotoxic inflammation. This can lead to effects beyond the central nervous system (CNS). To stimulate discussion, this commentary addresses four questions: What drives the development of human immunodeficiency virus (HIV)-associated neurocognitive disorders, does the phenotype of macrophages in the CNS spur development of HIV encephalitis (HIVE), does continual activation of astrocytes drive the development of HIV-associated neurocognitive disorders/subclinical disease, and neuroinflammation: friend or foe? A unifying theory that connects each question is the issue of continued activation of glial cells, even in the apparent absence of simian immunodeficiency virus/HIV in the CNS. As the CNS innate immune system is distinct from the rest of the body, it is likely there could be a number of activation profiles not observed elsewhere.
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Affiliation(s)
- Elizabeth C. Delery
- Tulane National Primate Research Center, Covington, Louisiana
- Tulane Program in Biomedical Sciences, Tulane Medical School, New Orleans, Louisiana
- Department of Microbiology and Immunology, Tulane Medical School, New Orleans, Louisiana
| | - Andrew G. MacLean
- Tulane National Primate Research Center, Covington, Louisiana
- Tulane Program in Biomedical Sciences, Tulane Medical School, New Orleans, Louisiana
- Department of Microbiology and Immunology, Tulane Medical School, New Orleans, Louisiana
- Tulane Brain Institute, Tulane University, New Orleans, Louisiana
- Center for Aging, School of Medicine, Tulane University, New Orleans, Louisiana
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10
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Kumar V, Mansfield J, Fan R, MacLean A, Li J, Mohan M. miR-130a and miR-212 Disrupt the Intestinal Epithelial Barrier through Modulation of PPARγ and Occludin Expression in Chronic Simian Immunodeficiency Virus-Infected Rhesus Macaques. THE JOURNAL OF IMMUNOLOGY 2018. [PMID: 29514950 DOI: 10.4049/jimmunol.1701148] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Intestinal epithelial barrier dysfunction is a well-known sequela of HIV/SIV infection that persists despite antiretroviral therapy. Although inflammation is a triggering factor, the underlying molecular mechanisms remain unknown. Emerging evidence suggests that epithelial barrier function is epigenetically regulated by inflammation-induced microRNAs (miRNAs). Accordingly, we profiled and characterized miRNA/mRNA expression exclusively in colonic epithelium and identified 46 differentially expressed miRNAs (20 upregulated and 26 downregulated) in chronically SIV-infected rhesus macaques (Macaca mulatta). We bioinformatically crossed the predicted miRNA targets to transcriptomic data and characterized miR-130a and miR-212 as both were predicted to interact with critical epithelial barrier-associated genes. Next, we characterized peroxisome proliferator-activated receptor γ (PPARγ) and occludin (OCLN), predicted targets of miR-130a and miR-212, respectively, as their downregulation has been strongly linked to epithelial barrier disruption and dysbiosis. Immunofluorescence, luciferase reporter, and overexpression studies confirmed the ability of miR-130a and miR-212 to decrease protein expression of PPARγ and OCLN, respectively, and reduce transepithelial electrical resistance. Because Δ-9-tetrahydrocannabinol exerted protective effects in the intestine in our previous studies, we successfully used it to reverse miR-130a- and miR-212-mediated reduction in transepithelial electrical resistance. Finally, ex vivo Δ-9-tetrahydrocannabinol treatment of colon tissue from chronically SIV-infected rhesus macaques significantly increased PPARγ expression. Our findings suggest that dysregulated miR-130a and miR-212 expression in colonic epithelium during chronic HIV/SIV infection can facilitate epithelial barrier disruption by downregulating OCLN and PPARγ expression. Most importantly, our results highlight the beneficial effects of cannabinoids on epithelial barrier function in not just HIV/SIV but potentially other chronic intestinal inflammatory diseases.
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Affiliation(s)
- Vinay Kumar
- Eurofins Bioanalytics USA, Saint Charles, MO 63304
| | - Joshua Mansfield
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433; and
| | - Rong Fan
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433; and
| | - Andrew MacLean
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433; and
| | - Jian Li
- Department of Global Biostatistics and Data Science, Tulane University School of Public Health and Tropical Medicine, New Orleans, LA 70112
| | - Mahesh Mohan
- Division of Comparative Pathology, Tulane National Primate Research Center, Covington, LA 70433; and
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11
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Robillard KN, Lee KM, Chiu KB, MacLean AG. Glial cell morphological and density changes through the lifespan of rhesus macaques. Brain Behav Immun 2016; 55:60-69. [PMID: 26851132 PMCID: PMC4899176 DOI: 10.1016/j.bbi.2016.01.006] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 01/04/2016] [Accepted: 01/12/2016] [Indexed: 11/18/2022] Open
Abstract
How aging impacts the central nervous system (CNS) is an area of intense interest. Glial morphology is known to affect neuronal and immune function as well as metabolic and homeostatic balance. Activation of glia, both astrocytes and microglia, occurs at several stages during development and aging. The present study analyzed changes in glial morphology and density through the entire lifespan of rhesus macaques, which are physiologically and anatomically similar to humans. We observed apparent increases in gray matter astrocytic process length and process complexity as rhesus macaques matured from juveniles through adulthood. These changes were not attributed to cell enlargement because they were not accompanied by proportional changes in soma or process volume. There was a decrease in white matter microglial process length as rhesus macaques aged. Aging was shown to have a significant effect on gray matter microglial density, with a significant increase in aged macaques compared with adults. Overall, we observed significant changes in glial morphology as macaques age indicative of astrocytic activation with subsequent increase in microglial density in aged macaques.
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Affiliation(s)
- Katelyn N Robillard
- Tulane National Primate Research Center, Covington, LA, United States; Southeastern Louisiana University, Hammond, LA, United States
| | - Kim M Lee
- Tulane National Primate Research Center, Covington, LA, United States; Tulane Program in Biomedical Sciences, Tulane University School of Medicine, New Orleans, LA, United States
| | - Kevin B Chiu
- Tulane National Primate Research Center, Covington, LA, United States
| | - Andrew G MacLean
- Tulane National Primate Research Center, Covington, LA, United States; Tulane Program in Biomedical Sciences, Tulane University School of Medicine, New Orleans, LA, United States; Tulane Program in Neuroscience, Tulane University, New Orleans, LA, United States; Department of Microbiology and Immunology, Tulane University School of Medicine, New Orleans, LA, United States.
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12
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Lee KM, Chiu KB, Sansing HA, Didier PJ, Lackner AA, MacLean AG. The flavivirus dengue induces hypertrophy of white matter astrocytes. J Neurovirol 2016; 22:831-839. [PMID: 27273075 DOI: 10.1007/s13365-016-0461-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2016] [Revised: 05/09/2016] [Accepted: 05/26/2016] [Indexed: 11/25/2022]
Abstract
Flaviviruses, including Zika and dengue (DENV), pose a serious global threat to human health. Of the 50+ million humans infected with DENV annually, approximately 1-3 % progress to severe disease manifestations, dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS). Several factors are suspected to mediate the course of infection and pathogenesis of DENV infection. DHF and DSS are associated with vascular leakage and neurological sequelae. Our hypothesis was that altered astrocyte activation and morphology would alter the dynamics of the extracellular space and hence, neuronal and vascular function. We investigated the mechanisms of neuropathogenesis DENV infection in rhesus macaques. There were decreased numbers of GFAP immunopositive astrocytes per unit area, although those that remained had increased arbor length and complexity. This was combined with structural hypertrophy of white matter astrocytes in the absence of increased vascular leakage. Combined, these studies show how even low-grade infection with DENV induces measurable changes within the parenchyma of infected individuals.
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Affiliation(s)
- Kim M Lee
- Program in Biomedical Science, Tulane Medical School, New Orleans, LA, USA.,Tulane National Primate Research Center, Covington, LA, USA
| | - Kevin B Chiu
- Tulane National Primate Research Center, Covington, LA, USA.,Department of Biomedical Engineering, Covington, LA, USA
| | - Hope A Sansing
- Tulane National Primate Research Center, Covington, LA, USA
| | - Peter J Didier
- Tulane National Primate Research Center, Covington, LA, USA
| | - Andrew A Lackner
- Program in Biomedical Science, Tulane Medical School, New Orleans, LA, USA.,Tulane National Primate Research Center, Covington, LA, USA.,Department of Microbiology and Immunology, Tulane Medical School, New Orleans, LA, USA
| | - Andrew G MacLean
- Program in Biomedical Science, Tulane Medical School, New Orleans, LA, USA. .,Tulane National Primate Research Center, Covington, LA, USA. .,Department of Microbiology and Immunology, Tulane Medical School, New Orleans, LA, USA.
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13
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Reid WC, Ibrahim WG, Kim SJ, Denaro F, Casas R, Lee DE, Maric D, Hammoud DA. Characterization of neuropathology in the HIV-1 transgenic rat at different ages. J Neuroimmunol 2016; 292:116-25. [PMID: 26943969 DOI: 10.1016/j.jneuroim.2016.01.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/27/2016] [Accepted: 01/31/2016] [Indexed: 02/08/2023]
Abstract
The transgenic HIV-1 rat (Tg) is a commonly used neuroHIV model with documented neurologic/behavioral deficits. Using immunofluorescent staining of the Tg brain, we found astrocytic dysfunction/damage, as well as dopaminergic neuronal loss/dysfunction, both of which worsening significantly in the striatum with age. We saw mild microglial activation in young Tg brains, but this decreased with age. There were no differences in neurogenesis potential suggesting a neurodegenerative rather than a neurodevelopmental process. Gp120 CSF levels exceeded serum gp120 levels in some animals, suggesting local viral protein production in the brain. Further probing of the pathophysiology underlying astrocytic injury in this model is warranted.
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Affiliation(s)
- William C Reid
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Wael G Ibrahim
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Saejeong J Kim
- Frank Laboratory, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Frank Denaro
- Department of Biology, Morgan State University, Baltimore, MD, USA
| | - Rafael Casas
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Dianne E Lee
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA
| | - Dragan Maric
- Division of Intermural Research (DIR), National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health, Bethesda, MD, USA
| | - Dima A Hammoud
- Center for Infectious Disease Imaging (CIDI), Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
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14
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Lee KM, Chiu KB, Didier PJ, Baker KC, MacLean AG. Naltrexone treatment reverses astrocyte atrophy and immune dysfunction in self-harming macaques. Brain Behav Immun 2015; 50:288-297. [PMID: 26191654 PMCID: PMC4631668 DOI: 10.1016/j.bbi.2015.07.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/30/2015] [Accepted: 07/16/2015] [Indexed: 01/19/2023] Open
Abstract
The role of glia in the development and treatment of behavioral abnormalities is understudied. Recent reports have observed glial activation in several disorders, including depression, autism spectrum disorders and self-injurious behaviors (SIB). In the current study, we examined SIB in the physiologically and anatomically relevant nonhuman primate (NHP) model. At the Tulane National Primate Research Center (TNPRC), approximately 5% of singly housed macaques develop symptoms of SIB. We have previously demonstrated that naltrexone hydrochloride can be effective in reducing SIB. We have also demonstrated that the astrocytes of animals with SIB are distinctly atrophic and display heightened innate immune activation compared with control animals. We have added a third group of animals (five macaques identified with SIB and treated with oral naltrexone at a dose of 3.2mg/kg) to the previous cohort (six macaques with a history of SIB but not treated, and nine animals with no history of SIB) for this study. Gray and white matter astrocytes from frontal cortical tissue were examined following necropsy. Innate immune activation of astrocytes, which was increased in SIB animals, was markedly decreased in animals receiving naltrexone, as was atrophy of both grey and white matter astrocytes. This was concomitant with improved behavioral correlates. Preventing astrocyte activation in select areas of the brain to reduce injurious behavior is an innovative concept with implications for mental health studies. Differences in multiple areas of primate brain would help determine how self-injurious behavior develops. These studies suggest a stronger role for astrocytes in the cellular events associated with self-injurious behaviors.
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Affiliation(s)
- Kim M. Lee
- Tulane National Primate Research Center, Covington, LA, USA,Tulane Program in Biomedical Science, Tulane University School of Medicine, New Orleans, LA, USA
| | - Kevin B. Chiu
- Tulane National Primate Research Center, Covington, LA, USA,Department of Biomedical Engineering, Tulane University, New Orleans, LA, USA
| | | | - Kate C. Baker
- Tulane National Primate Research Center, Covington, LA, USA,Department of Psychology, Tulane University, New Orleans, LA, USA,Tulane Program in Neuroscience, Tulane University, New Orleans, LA, USA
| | - Andrew G. MacLean
- Tulane National Primate Research Center, Covington, LA, USA,Tulane Program in Biomedical Science, Tulane University School of Medicine, New Orleans, LA, USA,Tulane Program in Neuroscience, Tulane University, New Orleans, LA, USA,Department of Microbiology & Immunology, Tulane University School of Medicine, New Orleans, LA, USA,Corresponding author: Andrew G. MacLean, Tulane National Primate Research Center, Covington, LA, 70433. ‘phone: 985-871-6489
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15
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Neuropathogenesis of Chikungunya infection: astrogliosis and innate immune activation. J Neurovirol 2015; 22:140-8. [PMID: 26419894 DOI: 10.1007/s13365-015-0378-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 08/21/2015] [Accepted: 08/23/2015] [Indexed: 12/22/2022]
Abstract
Chikungunya, "that which bends up" in the Makonde dialect, is an emerging global health threat, with increasing incidence of neurological complications. Until 2013, Chikungunya infection had been largely restricted to East Africa and the Indian Ocean, with cases within the USA reported to be from foreign travel. However, in 2014, over 1 million suspected cases were reported in the Americas, and a recently infected human could serve as an unwitting reservoir for the virus resulting in an epidemic in the continental USA. Chikungunya infection is increasingly being associated with neurological sequelae. In this study, we sought to understand the role of astrocytes in the neuropathogenesis of Chikungunya infection. Even after virus has been cleared form the circulation, astrocytes were activated with regard to TLR2 expression. In addition, white matter astrocytes were hypertrophic, with increased arbor volume in gray matter astrocytes. Combined, these would alter the number and distribution of synapses that each astrocyte would be capable of forming. These results provide the first evidence that Chikungunya infection induces morphometric and innate immune activation of astrocytes in vivo. Perturbed glia-neuron signaling could be a major driving factor in the development of Chikungunya-associated neuropathology.
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16
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Lee KM, MacLean AG. New advances on glial activation in health and disease. World J Virol 2015; 4:42-55. [PMID: 25964871 PMCID: PMC4419121 DOI: 10.5501/wjv.v4.i2.42] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Revised: 01/23/2015] [Accepted: 02/11/2015] [Indexed: 02/05/2023] Open
Abstract
In addition to being the support cells of the central nervous system (CNS), astrocytes are now recognized as active players in the regulation of synaptic function, neural repair, and CNS immunity. Astrocytes are among the most structurally complex cells in the brain, and activation of these cells has been shown in a wide spectrum of CNS injuries and diseases. Over the past decade, research has begun to elucidate the role of astrocyte activation and changes in astrocyte morphology in the progression of neural pathologies, which has led to glial-specific interventions for drug development. Future therapies for CNS infection, injury, and neurodegenerative disease are now aimed at targeting astrocyte responses to such insults including astrocyte activation, astrogliosis and other morphological changes, and innate and adaptive immune responses.
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17
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Zayyad Z, Spudich S. Neuropathogenesis of HIV: from initial neuroinvasion to HIV-associated neurocognitive disorder (HAND). Curr HIV/AIDS Rep 2015; 12:16-24. [PMID: 25604237 PMCID: PMC4741099 DOI: 10.1007/s11904-014-0255-3] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Early in the HIV epidemic, the central nervous system (CNS) was recognized as a target of infection and injury in the advanced stages of disease. Though the most severe forms of HIV-associated neurocognitive disorder (HAND) related to severe immunosuppression are rare in the current era of widespread combination antiretroviral therapy (cART), evidence now supports pathological involvement of the CNS throughout the course of infection. Recent work suggests that the stage for HIV neuropathogenesis may be set with initial viral entry into the CNS, followed by initiation of pathogenetic processes including neuroinflammation and neurotoxicity, and establishment of local, compartmentalized HIV replication that may reflect a tissue reservoir for HIV. Key questions still exist as to when HIV establishes local infection in the CNS, which CNS cells are the primary targets of HIV, and what mechanistic processes underlie the injury to neurons that produce clinical symptoms of HAND. Advances in these areas will provide opportunities for improved treatment of patients with established HAND, prevention of neurological disease in those with early stage infection, and understanding of HIV tissue reservoirs that will aid efforts at HIV eradication.
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Affiliation(s)
- Zaina Zayyad
- Department of Neurology, Yale University School of Medicine, 300 George Street, Room 8300c, New Haven, CT, 06520, USA,
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