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Nass SR, Hahn YK, McLane VD, Varshneya NB, Damaj MI, Knapp PE, Hauser KF. Chronic HIV-1 Tat exposure alters anterior cingulate cortico-basal ganglia-thalamocortical synaptic circuitry, associated behavioral control, and immune regulation in male mice. Brain Behav Immun Health 2020; 5:100077. [PMID: 33083793 PMCID: PMC7571616 DOI: 10.1016/j.bbih.2020.100077] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2020] [Accepted: 04/25/2020] [Indexed: 12/28/2022] Open
Abstract
HIV-1 selectively disrupts neuronal integrity within specific brain regions, reflecting differences in viral tropism and/or the regional differences in the vulnerability of distinct neuronal subpopulations within the CNS. Deficits in prefrontal cortex (PFC)-mediated executive function and the resultant loss of behavioral control are a particularly debilitating consequence of neuroHIV. To explore how HIV-1 disrupts executive function, we investigated the effects of 48 h, 2 and/or 8 weeks of HIV-1 Tat exposure on behavioral control, synaptic connectivity, and neuroimmune function in the anterior cingulate cortex (ACC) and associated cortico-basal ganglia (BG)-thalamocortical circuitry in adult, Tat transgenic male mice. HIV-1 Tat exposure increased novelty-exploration in response to novel food, flavor, and environmental stimuli, suggesting that Tat triggers increased novelty-exploration in situations of competing motivation (e.g., drive to feed or explore vs. fear of novel, brightly lit open areas). Furthermore, Tat induced adaptability in response to an environmental stressor and pre-attentive filtering deficits. The behavioral insufficiencies coincided with decreases in the inhibitory pre- and post-synaptic proteins, synaptotagmin 2 and gephyrin, respectively, in the ACC, and alterations in specific pro- and anti-inflammatory cytokines out of 23 assayed. The interaction of Tat exposure and the resultant time-dependent, selective alterations in CCL4, CXCL1, IL-12p40, and IL-17A levels in the PFC predicted significant decreases in adaptability. Tat decreased dendritic spine density and cortical VGLUT1 inputs, while increasing IL-1β, IL-6, CCL5, and CCL11 in the striatum. Alternatively, IL-1α, CCL5, and IL-13 were decreased in the mediodorsal thalamus despite the absence of synaptic changes. Thus, HIV-1 Tat appears to uniquely and systematically disrupt immune regulation and the inhibitory and excitatory synaptic balance throughout the ACC-BG-thalamocortical circuitry resulting in a loss of behavioral control.
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Affiliation(s)
- Sara R. Nass
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, P.O. Box 980613, VA, 23298-0613, USA
| | - Yun K. Hahn
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, P.O. Box 980709, Richmond, VA, 23298-0709, USA
| | - Virginia D. McLane
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, P.O. Box 980613, VA, 23298-0613, USA
| | - Neil B. Varshneya
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, P.O. Box 980613, VA, 23298-0613, USA
| | - M. Imad Damaj
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, P.O. Box 980613, VA, 23298-0613, USA
| | - Pamela E. Knapp
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, P.O. Box 980613, VA, 23298-0613, USA
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, P.O. Box 980709, Richmond, VA, 23298-0709, USA
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, P.O. Box 980059, Richmond, VA, 23298-0059, USA
| | - Kurt F. Hauser
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, Richmond, P.O. Box 980613, VA, 23298-0613, USA
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, P.O. Box 980709, Richmond, VA, 23298-0709, USA
- Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Medical College of Virginia (MCV) Campus, P.O. Box 980059, Richmond, VA, 23298-0059, USA
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