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Thompson LJP, Genovese J, Hong Z, Singh MV, Singh VB. HIV-Associated Neurocognitive Disorder: A Look into Cellular and Molecular Pathology. Int J Mol Sci 2024; 25:4697. [PMID: 38731913 PMCID: PMC11083163 DOI: 10.3390/ijms25094697] [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: 03/25/2024] [Revised: 04/21/2024] [Accepted: 04/23/2024] [Indexed: 05/13/2024] Open
Abstract
Despite combined antiretroviral therapy (cART) limiting HIV replication to undetectable levels in the blood, people living with HIV continue to experience HIV-associated neurocognitive disorder (HAND). HAND is associated with neurocognitive impairment, including motor impairment, and memory loss. HIV has been detected in the brain within 8 days of estimated exposure and the mechanisms for this early entry are being actively studied. Once having entered into the central nervous system (CNS), HIV degrades the blood-brain barrier through the production of its gp120 and Tat proteins. These proteins are directly toxic to endothelial cells and neurons, and propagate inflammatory cytokines by the activation of immune cells and dysregulation of tight junction proteins. The BBB breakdown is associated with the progression of neurocognitive disease. One of the main hurdles for treatment for HAND is the latent pool of cells, which are insensitive to cART and prolong inflammation by harboring the provirus in long-lived cells that can reactivate, causing damage. Multiple strategies are being studied to combat the latent pool and HAND; however, clinically, these approaches have been insufficient and require further revisions. The goal of this paper is to aggregate the known mechanisms and challenges associated with HAND.
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Affiliation(s)
| | - Jessica Genovese
- Department of Life Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Zhenzi Hong
- Department of Life Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
| | - Meera Vir Singh
- Department of Neurology, University of Rochester, Rochester, NY 14642, USA
| | - Vir Bahadur Singh
- Department of Life Sciences, Albany College of Pharmacy and Health Sciences, Albany, NY 12208, USA
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2
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Borrajo A, Pérez-Rodríguez D, Fernández-Pereira C, Prieto-González JM, Agís-Balboa RC. Genomic Factors and Therapeutic Approaches in HIV-Associated Neurocognitive Disorders: A Comprehensive Review. Int J Mol Sci 2023; 24:14364. [PMID: 37762667 PMCID: PMC10531836 DOI: 10.3390/ijms241814364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 08/31/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
HIV-associated neurocognitive disorders (HANDs) still persist despite improved life expectancy, reduced viral loads, and decreased infection severity. The number of patients affected by HANDs ranges from (30 to 50) % of HIV-infected individuals. The pathological mechanisms contributing to HANDs and the most serious manifestation of the disease, HIV-associated dementia (HAD), are not yet well understood. Evidence suggests that these mechanisms are likely multifactorial, producing neurocognitive complications involving disorders such as neurogenesis, autophagy, neuroinflammation, and mitochondrial dysfunction. Over the years, multiple pharmacological approaches with specific mechanisms of action acting upon distinct targets have been approved. Although these therapies are effective in reducing viral loading to undetectable levels, they also present some disadvantages such as common side effects, the need for administration with a very high frequency, and the possibility of drug resistance. Genetic studies on HANDs provide insights into the biological pathways and mechanisms that contribute to cognitive impairment in people living with HIV-1. Furthermore, they also help identify genetic variants that increase susceptibility to HANDs and can be used to tailor treatment approaches for HIV-1 patients. Identification of the genetic markers associated with disease progression can help clinicians predict which individuals require more aggressive management and by understanding the genetic basis of the disorder, it will be possible to develop targeted therapies to mitigate cognitive impairment. The main goal of this review is to provide details on the epidemiological data currently available and to summarise the genetic (specifically, the genetic makeup of the immune system), transcriptomic, and epigenetic studies available on HANDs to date. In addition, we address the potential pharmacological therapeutic strategies currently being investigated. This will provide valuable information that can guide clinical care, drug development, and our overall understanding of these diseases.
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Affiliation(s)
- Ana Borrajo
- Department of Microbiology and Parasitology, Faculty of Pharmacy, Complutense University of Madrid, 28040 Madrid, Spain
- Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, 00133 Roma, Italy
| | - Daniel Pérez-Rodríguez
- NeuroEpigenetics Lab, Health Research Institute of Santiago de Compostela (IDIS), Santiago University Hospital Complex, 15706 Santiago de Compostela, Spain; (D.P.-R.); (C.F.-P.); (J.M.P.-G.)
- Facultade de Bioloxía, Universidade de Vigo (UVigo), Campus Universitario Lagoas-Marcosende, s/n, 36310 Vigo, Spain
| | - Carlos Fernández-Pereira
- NeuroEpigenetics Lab, Health Research Institute of Santiago de Compostela (IDIS), Santiago University Hospital Complex, 15706 Santiago de Compostela, Spain; (D.P.-R.); (C.F.-P.); (J.M.P.-G.)
- Translational Neuroscience Group, Galicia Sur Health Research Institute (IIS Galicia Sur), Area Sanitaria de Vigo-Hospital Álvaro Cunqueiro, SERGAS-UVIGO, CIBERSAM-ISCIII, 36213 Vigo, Spain
- Rare Disease and Pediatric Medicine Group, Galicia Sur Health Research Institute (IIS Galicia Sur), SERGAS-UVIGO, 36312 Vigo, Spain
| | - José María Prieto-González
- NeuroEpigenetics Lab, Health Research Institute of Santiago de Compostela (IDIS), Santiago University Hospital Complex, 15706 Santiago de Compostela, Spain; (D.P.-R.); (C.F.-P.); (J.M.P.-G.)
- Translational Research in Neurological Diseases (ITEN), Health Research Institute of Santiago de Compostela (IDIS), Santiago University Hospital Complex, 15706 Santiago de Compostela, Spain
- Servicio de Neurología, Hospital Clínico Universitario de Santiago, 15706 Santiago de Compostela, Spain
| | - Roberto Carlos Agís-Balboa
- NeuroEpigenetics Lab, Health Research Institute of Santiago de Compostela (IDIS), Santiago University Hospital Complex, 15706 Santiago de Compostela, Spain; (D.P.-R.); (C.F.-P.); (J.M.P.-G.)
- Translational Research in Neurological Diseases (ITEN), Health Research Institute of Santiago de Compostela (IDIS), Santiago University Hospital Complex, 15706 Santiago de Compostela, Spain
- Servicio de Neurología, Hospital Clínico Universitario de Santiago, 15706 Santiago de Compostela, Spain
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3
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Chiang W, Urban JM, Yanchik-Slade F, Stout A, Nilsson BL, Gelbard HA, Krauss TD. Hybrid Amyloid Quantum Dot Nanoassemblies to Probe Neuroinflammatory Damage. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555592. [PMID: 37693630 PMCID: PMC10491264 DOI: 10.1101/2023.08.30.555592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Various oligomeric species of amyloid-beta have been proposed to play different immunogenic roles in the cellular pathology of Alzheimer's Disease. However, investigating the role of a homogenous single oligomeric species has been difficult due to highly dynamic oligomerization and fibril formation kinetics that convert between many species. Here we report the design and construction of a quantum dot mimetic for larger spherical oligomeric amyloid species as an "endogenously" fluorescent proxy for this cytotoxic species to investigate its role in inducing inflammatory and stress response states in neuronal and glial cell types.
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Affiliation(s)
- Wesley Chiang
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, 14642
| | - Jennifer M. Urban
- Department of Chemistry, Rochester, New York 14627-0216, United States
| | | | - Angela Stout
- Center for Neurotherapeutics Discovery and Department of Neurology, University of Rochester Medical Center, Rochester, NY, 14642
| | | | - Harris A. Gelbard
- Center for Neurotherapeutics Discovery and Department of Neurology, University of Rochester Medical Center, Rochester, NY, 14642
- Departments of Pediatrics, Neuroscience, and Microbiology and Immunology, University of Rochester Medical Center, Rochester, NY, 14642
| | - Todd D. Krauss
- Department of Chemistry, Rochester, New York 14627-0216, United States
- The Institute of Optics, Rochester, New York 14627-0216, United States
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4
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Campbell GR, Rawat P, To RK, Spector SA. HIV-1 Tat Upregulates TREM1 Expression in Human Microglia. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2023; 211:429-442. [PMID: 37326481 PMCID: PMC10352590 DOI: 10.4049/jimmunol.2300152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/30/2023] [Indexed: 06/17/2023]
Abstract
Because microglia are a reservoir for HIV and are resistant to the cytopathic effects of HIV infection, they are a roadblock for any HIV cure strategy. We have previously identified that triggering receptor expressed on myeloid cells 1 (TREM1) plays a key role in human macrophage resistance to HIV-mediated cytopathogenesis. In this article, we show that HIV-infected human microglia express increased levels of TREM1 and are resistant to HIV-induced apoptosis. Moreover, upon genetic inhibition of TREM1, HIV-infected microglia undergo cell death in the absence of increased viral or proinflammatory cytokine expression or the targeting of uninfected cells. We also show that the expression of TREM1 is mediated by HIV Tat through a TLR4, TICAM1, PG-endoperoxide synthase 2, PGE synthase, and PGE2-dependent manner. These findings highlight the potential of TREM1 as a therapeutic target to eradicate HIV-infected microglia without inducing a proinflammatory response.
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Affiliation(s)
- Grant R. Campbell
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, SD
| | - Pratima Rawat
- Division of Infectious Diseases, Department of Pediatrics, University of California San Diego, La Jolla, CA
| | - Rachel K. To
- Division of Infectious Diseases, Department of Pediatrics, University of California San Diego, La Jolla, CA
| | - Stephen A. Spector
- Division of Infectious Diseases, Department of Pediatrics, University of California San Diego, La Jolla, CA
- Rady Children’s Hospital, San Diego, CA
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5
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Piper JA, Al Hammouri N, Jansen MI, Rodgers KJ, Musumeci G, Dhungana A, Ghorbanpour SM, Bradfield LA, Castorina A. L-Proline Prevents Endoplasmic Reticulum Stress in Microglial Cells Exposed to L-azetidine-2-carboxylic Acid. Molecules 2023; 28:4808. [PMID: 37375363 DOI: 10.3390/molecules28124808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 06/29/2023] Open
Abstract
L-Azetidine-2-carboxylic acid (AZE) is a non-protein amino acid that shares structural similarities with its proteogenic L-proline amino acid counterpart. For this reason, AZE can be misincorporated in place of L-proline, contributing to AZE toxicity. In previous work, we have shown that AZE induces both polarization and apoptosis in BV2 microglial cells. However, it is still unknown if these detrimental effects involve endoplasmic reticulum (ER) stress and whether L-proline co-administration prevents AZE-induced damage to microglia. Here, we investigated the gene expression of ER stress markers in BV2 microglial cells treated with AZE alone (1000 µM), or co-treated with L-proline (50 µM), for 6 or 24 h. AZE reduced cell viability, nitric oxide (NO) secretion and caused a robust activation of the unfolded protein response (UPR) genes (ATF4, ATF6, ERN1, PERK, XBP1, DDIT3, GADD34). These results were confirmed by immunofluorescence in BV2 and primary microglial cultures. AZE also altered the expression of microglial M1 phenotypic markers (increased IL-6, decreased CD206 and TREM2 expression). These effects were almost completely prevented upon L-proline co-administration. Finally, triple/quadrupole mass spectrometry demonstrated a robust increase in AZE-bound proteins after AZE treatment, which was reduced by 84% upon L-proline co-supplementation. This study identified ER stress as a pathogenic mechanism for AZE-induced microglial activation and death, which is reversed by co-administration of L-proline.
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Affiliation(s)
- Jordan Allan Piper
- Laboratory of Cellular and Molecular Neuroscience (LCMN), School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Nour Al Hammouri
- Laboratory of Cellular and Molecular Neuroscience (LCMN), School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Margo Iris Jansen
- Laboratory of Cellular and Molecular Neuroscience (LCMN), School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Kenneth J Rodgers
- Neurotoxin Research Group, School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Giuseppe Musumeci
- Department of Biomedical and Biotechnological Sciences, Section of Anatomy, Histology and Movement Science, School of Medicine, University of Catania, Via S. Sofia n°97, 95123 Catania, Italy
| | - Amolika Dhungana
- School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Sahar Masoumeh Ghorbanpour
- School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Laura A Bradfield
- School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
| | - Alessandro Castorina
- Laboratory of Cellular and Molecular Neuroscience (LCMN), School of Life Sciences, Faculty of Science, University of Technology Sydney, P.O. Box 123, Broadway, Sydney, NSW 2007, Australia
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6
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McMillan RE, Wang E, Carlin AF, Coufal NG. Human microglial models to study host-virus interactions. Exp Neurol 2023; 363:114375. [PMID: 36907350 PMCID: PMC10521930 DOI: 10.1016/j.expneurol.2023.114375] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 02/13/2023] [Accepted: 03/02/2023] [Indexed: 03/14/2023]
Abstract
Microglia, the resident macrophage of the central nervous system, are increasingly recognized as contributing to diverse aspects of human development, health, and disease. In recent years, numerous studies in both mouse and human models have identified microglia as a "double edged sword" in the progression of neurotropic viral infections: protecting against viral replication and cell death in some contexts, while acting as viral reservoirs and promoting excess cellular stress and cytotoxicity in others. It is imperative to understand the diversity of human microglial responses in order to therapeutically modulate them; however, modeling human microglia has been historically challenging due to significant interspecies differences in innate immunity and rapid transformation upon in vitro culture. In this review, we discuss the contribution of microglia to the neuropathogenesis of key neurotropic viral infections: human immunodeficiency virus 1 (HIV-1), Zika virus (ZIKV), Japanese encephalitis virus (JEV), West Nile virus (WNV), Herpes simplex virus (HSV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We pay special attention to recent work with human stem cell-derived microglia and propose strategies to leverage these powerful models to further uncover species- and disease-specific microglial responses and novel therapeutic interventions for neurotropic viral infections.
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Affiliation(s)
- Rachel E McMillan
- Biomedical Sciences Graduate Program, University of California, San Diego, La Jolla, CA 92093, United States of America; Department of Pathology and Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, United States of America
| | - Ellen Wang
- Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, CA 92093, United States of America; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92093, United States of America
| | - Aaron F Carlin
- Department of Pathology and Medicine, University of California, San Diego, School of Medicine, La Jolla, CA 92093, United States of America.
| | - Nicole G Coufal
- Department of Pediatrics, University of California, San Diego, School of Medicine, La Jolla, CA 92093, United States of America; Sanford Consortium for Regenerative Medicine, La Jolla, CA 92093, United States of America.
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7
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Zhou X, Zhou S, Tao J, Gao Y, Meng G, Cao D, Gao L. HIV-1 Tat drives the Fabp4/NF-κB feedback loop in microglia to mediate inflammatory response and neuronal apoptosis. J Neurovirol 2022; 28:483-496. [PMID: 36070137 DOI: 10.1007/s13365-022-01094-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 08/02/2022] [Accepted: 08/23/2022] [Indexed: 01/13/2023]
Abstract
Fatty acid-binding proteins (FABPs) are relevant to multiple neurodegenerative diseases. However, the roles and mechanisms of FABPs in HIV-associated neurocognitive disorder (HAND) remain yet unclear. In this study, cultured BV-2 microglial cells and HT-22 neuronal cells were used for in vitro experiments and HAND mouse models were constructed through intracerebroventricular injection of lentiviral vectors for in vivo experiments. FABP expression was determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot. The interrelationship between Fabp4 and NF-κB signaling was investigated using chromatin immunoprecipitation, qRT-PCR, and Western blot. The role of Fabp4 in regulating inflammatory response was determined using qRT-PCR, enzyme-linked immunosorbent assay, Western blot, and immunofluorescence staining. Cell viability and apoptosis were analyzed using cell counting kit-8 assay and flow cytometry assay, respectively. Our results suggested an upregulation of Fabp4 expression in the presence of Tat. Tat-induced Fabp4 expression was directly regulated by NF-κB p65, followed by, Fabp4 facilitating Tat-activated NF-κB signaling pathway. We also observed that Fabp4 knockdown in microglial cells significantly suppressed inflammatory response and neuronal apoptosis both in vitro and in vivo. In conclusion, the presence of Tat in microglial cells results in Fabp4 and NF-κB to form a positive feedback loop leading to exacerbate inflammatory response and neuronal apoptosis.
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Affiliation(s)
- Xiaodan Zhou
- Department of Hematology, Affiliated Hospital 2 of Nantong University and First People's Hospital of Nantong City, Nantong, 226001, People's Republic of China
| | - Shuhui Zhou
- Department of Oncology, Nantong Hospital of Traditional Chinese Medicine, Affiliated Traditional Chinese Medicine Hospital of Nantong University, Nantong, 226001, People's Republic of China
| | - Jian Tao
- Department of Hematology, Affiliated Hospital 2 of Nantong University and First People's Hospital of Nantong City, Nantong, 226001, People's Republic of China
| | - Yanan Gao
- Department of Gastroenterology, Affiliated Hospital of Nantong University, Nantong University, Nantong, 226001, People's Republic of China
| | - Gaoqiang Meng
- Department of Neurosurgery, Affiliated Hospital 2 of Nantong University and First People's Hospital of Nantong City, Nantong, 226001, People's Republic of China
| | - Duo Cao
- College of Life Science, Yan'an University, Yan'an, 716000, People's Republic of China.
| | - Lin Gao
- Medical Research Center, Affiliated Hospital 2 of Nantong University and First People's Hospital of Nantong City, Haier Lane North Road No. 6, Nantong, 226001, Jiangsu, People's Republic of China.
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8
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Scanlan A, Zhang Z, Koneru R, Reece M, Gavegnano C, Anderson AM, Tyor W. A Rationale and Approach to the Development of Specific Treatments for HIV Associated Neurocognitive Impairment. Microorganisms 2022; 10:2244. [PMID: 36422314 PMCID: PMC9699382 DOI: 10.3390/microorganisms10112244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 11/03/2022] [Accepted: 11/08/2022] [Indexed: 05/22/2024] Open
Abstract
Neurocognitive impairment (NCI) associated with HIV infection of the brain impacts a large proportion of people with HIV (PWH) regardless of antiretroviral therapy (ART). While the number of PWH and severe NCI has dropped considerably with the introduction of ART, the sole use of ART is not sufficient to prevent or arrest NCI in many PWH. As the HIV field continues to investigate cure strategies, adjunctive therapies are greatly needed. HIV imaging, cerebrospinal fluid, and pathological studies point to the presence of continual inflammation, and the presence of HIV RNA, DNA, and proteins in the brain despite ART. Clinical trials exploring potential adjunctive therapeutics for the treatment of HIV NCI over the last few decades have had limited success. Ideally, future research and development of novel compounds need to address both the HIV replication and neuroinflammation associated with HIV infection in the brain. Brain mononuclear phagocytes (MPs) are the primary instigators of inflammation and HIV protein expression; therefore, adjunctive treatments that act on MPs, such as immunomodulating agents, look promising. In this review, we will highlight recent developments of innovative therapies and discuss future approaches for HIV NCI treatment.
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Affiliation(s)
- Aaron Scanlan
- Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Zhan Zhang
- Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Rajeth Koneru
- Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
| | - Monica Reece
- Department of Pathology, Division of Experimental Pathology, Emory University, Atlanta, GA 30322, USA
- Department of Pharmacology and Chemical Biology, Emory University, Atlanta, GA 30322, USA
| | - Christina Gavegnano
- Department of Pathology, Division of Experimental Pathology, Emory University, Atlanta, GA 30322, USA
- Department of Pharmacology and Chemical Biology, Emory University, Atlanta, GA 30322, USA
| | - Albert M. Anderson
- Department of Medicine, Division of Infectious Diseases, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - William Tyor
- Atlanta Veterans Affairs Medical Center, Decatur, GA 30033, USA
- Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA
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9
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Çetin G, Studencka-Turski M, Venz S, Schormann E, Junker H, Hammer E, Völker U, Ebstein F, Krüger E. Immunoproteasomes control activation of innate immune signaling and microglial function. Front Immunol 2022; 13:982786. [PMID: 36275769 PMCID: PMC9584546 DOI: 10.3389/fimmu.2022.982786] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Microglia are the resident immune cells of the central nervous system (CNS) and play a major role in the regulation of brain homeostasis. To maintain their cellular protein homeostasis, microglia express standard proteasomes and immunoproteasomes (IP), a proteasome isoform that preserves protein homeostasis also in non-immune cells under challenging conditions. The impact of IP on microglia function in innate immunity of the CNS is however not well described. Here, we establish that IP impairment leads to proteotoxic stress and triggers the unfolded and integrated stress responses in mouse and human microglia models. Using proteomic analysis, we demonstrate that IP deficiency in microglia results in profound alterations of the ubiquitin-modified proteome among which proteins involved in the regulation of stress and immune responses. In line with this, molecular analysis revealed chronic activation of NF-κB signaling in IP-deficient microglia without further stimulus. In addition, we show that IP impairment alters microglial function based on markers for phagocytosis and motility. At the molecular level IP impairment activates interferon signaling promoted by the activation of the cytosolic stress response protein kinase R. The presented data highlight the importance of IP function for the proteostatic potential as well as for precision proteolysis to control stress and immune signaling in microglia function.
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Affiliation(s)
- Gonca Çetin
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Maja Studencka-Turski
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Simone Venz
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Eileen Schormann
- Institute of Biochemistry, Charité – University Medicine Berlin, Berlin, Germany
| | - Heike Junker
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Elke Hammer
- Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Uwe Völker
- Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Greifswald, Germany
| | - Frédéric Ebstein
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Elke Krüger
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
- *Correspondence: Elke Krüger,
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