title: Inhibition of catechol-O-methyl transferase (COMT) by tolcapone restores reductions in microtubule-associated protein 2 (MAP2) and synaptophysin (SYP) following exposure of neuronal cells to neurotropic HIV.
abstract: This investigation aimed to assess whether inhibition of cathecol-O-methyl transferase (COMT) by tolcapone could provide neuroprotection against HIV-associated neurodegenerative effects. This study was conducted based on a previous work, which showed that a single nucleotide polymorphism (SNP) at position 158 (val158met) in COMT, resulted in 40 % lower COMT activity. Importantly, this reduction confers a protective effect against HIV-associated neurocognitive disorders (HAND), which have been linked to HIV-associated brain changes. SH-SY5Y-differentiated neurons were exposed to macrophage-propagated HIV (neurotropic MACS2-Br strain) in the presence or absence of tolcapone for 6 days. RNA was extracted, and qPCR was performed using Qiagen RT2 custom array consisting of genes for neuronal and synaptic integrity, COMT and pro-inflammatory markers. Immunofluorescence was conducted to validate the gene expression changes at the protein level. Our findings demonstrated that HIV significantly increased the messenger RNA (mRNA) expression of COMT while reducing the expression of microtubule-associated protein 2 (MAP2) (p = 0.0015) and synaptophysin (SYP) (p = 0.012) compared to control. A concomitant exposure of tolcapone ameliorated the perturbed expression of MAP2 (p = 0.009) and COMT (p = 0.024) associated with HIV. Immunofluorescence revealed a trend reduction of SYP and MAP2 with exposure to HIV and that concomitant exposure of tolcapone increased SYP (p = 0.016) compared to HIV alone. Our findings demonstrated in vitro that inhibition of COMT can ameliorate HIV-associated neurodegenerative changes that resulted in the decreased expression of the structural and synaptic components MAP2 and SYP. As HIV-associated dendritic and synaptic damage are contributors to HAND, inhibition of COMT may represent a potential strategy for attenuating or preventing some of the symptoms of HAND.
authors.affiliation: Department of Psychiatry, The University of Melbourne, Level 1 North, Main Block, Royal Hospital, 3050, Melbourne, VIC, Australia.|Centre for Neural Engineering, Department of Electrical and Electronic Engineering, The University of Melbourne, Melbourne, Australia.
authors.forename: Ting Ting
authors.initials: TT
authors.lastname: Lee
authors.affiliation: Department of Psychiatry, The University of Melbourne, Level 1 North, Main Block, Royal Hospital, 3050, Melbourne, VIC, Australia.|Centre for Neural Engineering, Department of Electrical and Electronic Engineering, The University of Melbourne, Melbourne, Australia.
authors.forename: Gursharan
authors.initials: G
authors.lastname: Chana
authors.affiliation: Centre for Biomedical Research, Burnet Institute, Melbourne, Australia.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Gorry
authors.affiliation: Centre for Biomedical Research, Burnet Institute, Melbourne, Australia.
authors.forename: Anne
authors.initials: A
authors.lastname: Ellett
authors.affiliation: Department of Psychiatry, The University of Melbourne, Level 1 North, Main Block, Royal Hospital, 3050, Melbourne, VIC, Australia.
authors.forename: Chad A
authors.initials: CA
authors.lastname: Bousman
authors.affiliation: Centre for Biomedical Research, Burnet Institute, Melbourne, Australia.
authors.forename: Melissa J
authors.initials: MJ
authors.lastname: Churchill
authors.affiliation: Centre for Biomedical Research, Burnet Institute, Melbourne, Australia.
authors.forename: Lachlan R
authors.initials: LR
authors.lastname: Gray
authors.affiliation: Department of Psychiatry, The University of Melbourne, Level 1 North, Main Block, Royal Hospital, 3050, Melbourne, VIC, Australia. ieverall@unimelb.edu.au.|NorthWestern Mental Health, Melbourne Health, Melbourne, Australia. ieverall@unimelb.edu.au.|The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia. ieverall@unimelb.edu.au.
authors.forename: Ian P
authors.initials: IP
authors.lastname: Everall
mesh_terms: D001577:Benzophenones / Q000494:pharmacology*; D002394:Catechol O-Methyltransferase / Q000378:metabolism*; D065098:Catechol O-Methyltransferase Inhibitors / Q000494:pharmacology*; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D006678:HIV / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism* / Q000821:virology; D009596:Nitrophenols / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction; D016708:Synaptophysin / Q000378:metabolism*; D000077867:Tolcapone; D059467:Transcriptome
chemical_list: D001577:Benzophenones; D065098:Catechol O-Methyltransferase Inhibitors; C489788:MAP2 protein, human; D008869:Microtubule-Associated Proteins; D009596:Nitrophenols; C569014:SYP protein, human; D016708:Synaptophysin; D000077867:Tolcapone; C588010:COMT protein, human; D002394:Catechol O-Methyltransferase
keywords: COMT protein; HIV; Human; MAP2 microtubule-associated protein 2; Synaptophysin; Tolcapone