Unravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomics

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dc.contributor.advisorBlackburn, Jonathan Men_ZA
dc.contributor.advisorSoares, Nelsonen_ZA
dc.contributor.authorGurwitz, Kim Tamaraen_ZA
dc.date.accessioned2017-01-16T13:45:25Z
dc.date.available2017-01-16T13:45:25Z
dc.date.issued2016en_ZA
dc.description.abstractA significant proportion of human immunodeficiency virus type 1 (HIV)-positive individuals are affected by the cognitive, motor and behavioural dysfunction that characterises HIV associated neurocognitive disorders. While the molecular aetiology of this important HIV complication remains largely uncharacterised, HIV transactivator of transcription (HIV-Tat) has been identified as a plausible aetiological cause. Here we have used mass spectrometry-based discovery proteomics to identify the quantitative, cell-wide changes that occur when non-transformed, differentiated human neurons are treated with HIV-Tat over time, as a novel cell culture model representing the initial progression of HIV associated neurocognitive disorders, and as a means to identify putative biomarkers for the illness. We found that our stem cell-based model system displayed morphological and functional neuronal properties and using a Q-Exactive mass spectrometer, we identified over 4000 protein groups (FDR < 0.01) in this system with 131,118 and 45 protein groups differentially expressed at 6, 24 and 48 hours post treatment, respectively. We found changes to the gene expression machinery (nucleic acid binding proteins), which suggests that HIV-Tat is involved in preparing the host cell for altered transcriptional and translational activity. We also found cytoskeletal dysregulation in response to HIV-Tat treatment. The 24-hour time point of the time course experiment was largely corroborated with a repeat experiment. A repeat of the entire time course experiment at a lower cell confluence showed that the effect of HIV-Tat treatment to the gene expression machinery was unchanged by cell confluence, while the effect to cytoskeletal proteins upon HIV-Tat treatment was present, but less prominent, in lower cell confluence samples. We hypothesise that the gene-expression-machinery effect may be a biphasic response. We further hypothesise that cytoskeletal dysregulation may form part of the molecular mechanism responsible for synaptic injury - as the cytoskeleton is crucial for synapse development and maintenance - and may contribute to memory impairment in HIV associated neurocognitive disorder patients.en_ZA
dc.identifier.apacitationGurwitz, K. T. (2016). <i>Unravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomics</i>. (Thesis). University of Cape Town ,Faculty of Health Sciences ,Division of Medical Biochemistry. Retrieved from http://hdl.handle.net/11427/22733en_ZA
dc.identifier.chicagocitationGurwitz, Kim Tamara. <i>"Unravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomics."</i> Thesis., University of Cape Town ,Faculty of Health Sciences ,Division of Medical Biochemistry, 2016. http://hdl.handle.net/11427/22733en_ZA
dc.identifier.citationGurwitz, K. 2016. Unravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomics. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Gurwitz, Kim Tamara AB - A significant proportion of human immunodeficiency virus type 1 (HIV)-positive individuals are affected by the cognitive, motor and behavioural dysfunction that characterises HIV associated neurocognitive disorders. While the molecular aetiology of this important HIV complication remains largely uncharacterised, HIV transactivator of transcription (HIV-Tat) has been identified as a plausible aetiological cause. Here we have used mass spectrometry-based discovery proteomics to identify the quantitative, cell-wide changes that occur when non-transformed, differentiated human neurons are treated with HIV-Tat over time, as a novel cell culture model representing the initial progression of HIV associated neurocognitive disorders, and as a means to identify putative biomarkers for the illness. We found that our stem cell-based model system displayed morphological and functional neuronal properties and using a Q-Exactive mass spectrometer, we identified over 4000 protein groups (FDR < 0.01) in this system with 131,118 and 45 protein groups differentially expressed at 6, 24 and 48 hours post treatment, respectively. We found changes to the gene expression machinery (nucleic acid binding proteins), which suggests that HIV-Tat is involved in preparing the host cell for altered transcriptional and translational activity. We also found cytoskeletal dysregulation in response to HIV-Tat treatment. The 24-hour time point of the time course experiment was largely corroborated with a repeat experiment. A repeat of the entire time course experiment at a lower cell confluence showed that the effect of HIV-Tat treatment to the gene expression machinery was unchanged by cell confluence, while the effect to cytoskeletal proteins upon HIV-Tat treatment was present, but less prominent, in lower cell confluence samples. We hypothesise that the gene-expression-machinery effect may be a biphasic response. We further hypothesise that cytoskeletal dysregulation may form part of the molecular mechanism responsible for synaptic injury - as the cytoskeleton is crucial for synapse development and maintenance - and may contribute to memory impairment in HIV associated neurocognitive disorder patients. DA - 2016 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 2016 T1 - Unravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomics TI - Unravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomics UR - http://hdl.handle.net/11427/22733 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/22733
dc.identifier.vancouvercitationGurwitz KT. Unravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomics. [Thesis]. University of Cape Town ,Faculty of Health Sciences ,Division of Medical Biochemistry, 2016 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/22733en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentDivision of Medical Biochemistryen_ZA
dc.publisher.facultyFaculty of Health Sciencesen_ZA
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherMedical Biochemistryen_ZA
dc.titleUnravelling the molecular mechanisms of HIV associated neurocognitive disorders through mass spectrometry-based proteomicsen_ZA
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMSc (Med)en_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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