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Levine AJ, Soontornniyomkij V, Masliah E, Sinsheimer JS, Ji SS, Horvath S, Singer EJ, Kallianpur A, Moore DJ. A candidate gene study of intermediate histopathological phenotypes in HIV-associated neurocognitive disorders. J Neurovirol 2020; 26:496-508. [PMID: 32394397 DOI: 10.1007/s13365-020-00846-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/13/2020] [Accepted: 04/22/2020] [Indexed: 11/29/2022]
Abstract
HIV-associated neurocognitive disorders (HAND) describe a spectrum of neuropsychological impairment caused by HIV-1 infection. While the sequence of cellular and physiological events that lead to HAND remains obscure, it likely involves chronic neuroinflammation. Host genetic markers that increase the risk for HAND have been reported, but replication of such studies is lacking, possibly due to inconsistent application of a behavioral phenotype across studies. In the current study, we used histopathologic phenotypes in order to validate putative risk alleles for HAND. The National NeuroAIDS Tissue Consortium, a longitudinal study of the neurologic manifestations of HIV. Data and specimens were obtained from 175 HIV-infected adults. After determining several potential covariates of neurocognitive functioning, we quantified levels of six histopathological markers in the frontal lobe in association with neurocognitive functioning: SYP, MAP 2, HLA-DR, Iba1, GFAP, and β-amyloid. We then determined alleles of 15 candidate genes for their associations with neurocognitive functioning and histopathological markers. Finally, we identified the most plausible causal pathway based on our data using a multi-stage linear regression-based mediation analysis approach. None of the genetic markers were associated with neurocognitive functioning. Of the histopathological markers, only MAP 2 and SYP were associated with neurocognitive functioning; however, MAP 2 and SYP did not vary as a function of genotype. Mediation analysis suggests a causal pathway in which presynaptic degeneration (SYP) leads to somatodendritic degeneration (MAP 2) and ultimately neurocognitive impairment. This study did not support the role of host genotype in the histopathology underlying HAND. The findings lend further support for synaptodendritic degeneration as the proximal underlying neuropathological substrate of HAND.
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Affiliation(s)
- Andrew J Levine
- Department of Neurology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA.
| | | | - Eliezer Masliah
- Departments of Neurosciences and Pathology, University of California San Diego School of Medicine, San Diego, CA, USA
| | - Janet S Sinsheimer
- Departments of Human Genetics and Computational Biology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA.,Department of Biostatistics, UCLA Fielding School of Public Health, Los Angeles, CA, USA
| | - Sarah S Ji
- Department of Biostatistics, UCLA Fielding School of Public Health, Los Angeles, CA, USA
| | - Steve Horvath
- Department of Biostatistics, UCLA Fielding School of Public Health, Los Angeles, CA, USA.,Department of Human Genetics, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - Elyse J Singer
- Department of Neurology, David Geffen School of Medicine at the University of California, Los Angeles, CA, USA
| | - Asha Kallianpur
- Department of Molecular Medicine, Genomic Medicine, Medicine, & Pediatrics, Cleveland Clinic/Lerner Research Institute, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA
| | - David J Moore
- Department of Psychiatry, University of California San Diego School of Medicine, San Diego, CA, USA
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Sokolova IV, Szucs A, Sanna PP. Reduced intrinsic excitability of CA1 pyramidal neurons in human immunodeficiency virus (HIV) transgenic rats. Brain Res 2019; 1724:146431. [PMID: 31491420 PMCID: PMC6939992 DOI: 10.1016/j.brainres.2019.146431] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 08/24/2019] [Accepted: 08/30/2019] [Indexed: 10/26/2022]
Abstract
The hippocampus is involved in key neuronal circuits that underlie cognition, memory, and anxiety, and it is increasingly recognized as a vulnerable structure that contributes to the pathogenesis of HIV-associated neurocognitive disorder (HAND). However, the mechanisms responsible for hippocampal dysfunction in neuroHIV remain unknown. The present study used HIV transgenic (Tg) rats and patch-clamp electrophysiological techniques to study the effects of the chronic low-level expression of HIV proteins on hippocampal CA1 pyramidal neurons. The dorsal and ventral areas of the hippocampus are involved in different neurocircuits and thus were evaluated separately. We found a significant decrease in the intrinsic excitability of CA1 neurons in the dorsal hippocampus in HIV Tg rats by comparing neuronal spiking induced by current step injections and by dynamic clamp to simulate neuronal spiking activity. The decrease in excitability in the dorsal hippocampus was accompanied by a higher rate of excitatory postsynaptic currents (EPSCs), whereas CA1 pyramidal neurons in the ventral hippocampus in HIV Tg rats had higher EPSC amplitudes. We also observed a reduction of hyperpolarization-activated nonspecific cationic current (Ih) in both the dorsal and ventral hippocampus. Neurotoxic HIV proteins have been shown to increase neuronal excitation. The lower excitability of CA1 pyramidal neurons that was observed herein may represent maladaptive homeostatic plasticity that seeks to stabilize baseline neuronal firing activity but may disrupt neural network function and contribute to HIV-associated neuropsychological disorders, such as HAND and depression.
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Affiliation(s)
- Irina V Sokolova
- The Scripps Research Institute, Department of Immunology and Microbiology, 10550 North Torrey Pines Road, La Jolla, CA 92037-1000, United States
| | - Attila Szucs
- The Scripps Research Institute, Department of Immunology and Microbiology, 10550 North Torrey Pines Road, La Jolla, CA 92037-1000, United States; University of California, San Diego, BioCircuits Institute, 9500 Gilman Drive, La Jolla, CA 92039-0328, United States; MTA-ELTE-NAP B Neuronal Cell Biology Research Group, Eötvös Lóránd University, Budapest, Hungary
| | - Pietro Paolo Sanna
- The Scripps Research Institute, Department of Immunology and Microbiology, 10550 North Torrey Pines Road, La Jolla, CA 92037-1000, United States.
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Levine AJ, Soontornniyomkij V, Achim CL, Masliah E, Gelman BB, Sinsheimer JS, Singer EJ, Moore DJ. Multilevel analysis of neuropathogenesis of neurocognitive impairment in HIV. J Neurovirol 2015; 22:431-41. [PMID: 26637429 DOI: 10.1007/s13365-015-0410-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Revised: 11/13/2015] [Accepted: 11/19/2015] [Indexed: 12/31/2022]
Abstract
The neuropathogenesis of HIV-associated neurocognitive disorders (HAND) remains puzzling. We interrogated several levels of data (host genetic, histopathology, brain viral load, and neurocognitive) to identify histopathological changes most relevant to HAND. The design of the study is a clinicopathological study employing genetic association analyses. Data and brain tissue from 80 HIV-infected adults were used. Markers in monocyte chemoattractant protein-1 (MCP-1), interleukin 1-alpha (IL1-α), macrophage inflammatory protein 1-alpha (MIP1-α), DRD3, DRD2, and apolipoprotein E (ApoE) were genotyped. Microtubule associated protein 2 (MAP2), synaptophysin (SYP), human leukocyte antigen-DR (HLA-DR), glial fibrillary acidic protein (GFAP), amyloid beta (A-Beta), and ionized calcium-binding adaptor molecule-1 (Iba-1) immunoreactivity were quantified in the frontal cortex, putamen, and hippocampus. A composite score for each marker (mean of the three brain regions) was used. Neurocognitive functioning and other clinical variables were determined within 1 year of death. Brain HIV RNA viral load was available for a subset of cases. MAP2 and SYP proved most relevant to neurocognitive functioning. Immunoreactivity of these markers, as well as A-Beta and Iba-1, was correlated with brain HIV RNA viral load. Several genetic markers in combination with other factors predicted histopathology: HIV blood viral load, MIP1-α genotype, and DRD3 genotype predicted Iba-1 immunoreactivity; the duration of infection and IL1-α genotype predicted GFAP immunoreactivity; ApoE genotype and age at death predicted A-Beta immunoreactivity. These data indicate that HIV replication in the brain is the primary driving force leading to neuroinflammation and dysfunctional protein clearance, as reflected by A-Beta and Iba-1. Downstream to these changes are synaptodendritic degeneration, which is the immediate histopathological substrate of the neurocognitive impairment characteristic of HAND. These intermediate histopathological phenotypes are influenced by host genetic polymorphisms in genes encoding cytokines/chemokines, neuronal protein clearance pathways, and dopaminergic factors.
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Affiliation(s)
- Andrew J Levine
- Department of Neurology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA.
| | | | - Cristian L Achim
- Departments of Psychiatry and Pathology, University of California San Diego School of Medicine, La Jolla, CA, USA
| | - Eliezer Masliah
- Departments of Neurosciences and Pathology, University of California San Diego School of Medicine, La Jolla, CA, USA
| | - Benjamin B Gelman
- Department of Pathology, University of Texas Medical Branch, Galveston, TX, USA
| | - Janet S Sinsheimer
- Departments of Human Genetics and Biomathematics, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
| | - Elyse J Singer
- Department of Neurology, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, CA, USA
| | - David J Moore
- Department of Psychiatry, University of California San Diego School of Medicine, La Jolla, CA, USA
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