Exploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain

dc.contributor.advisorRaimondo, Joseph
dc.contributor.advisorde Lange, Anja
dc.contributor.authorTinelli, Sasha
dc.date.accessioned2022-03-22T09:32:01Z
dc.date.available2022-03-22T09:32:01Z
dc.date.issued2021
dc.date.updated2022-03-22T06:02:27Z
dc.description.abstractEpilepsy directly affects approximately 50 million people globally and is the most common neurological disorder in sub-Saharan Africa, mainly due to high rates of neuroinfections and head trauma experienced by people in the region. A common factor in these causes of acquired epilepsy is their association with significant neuroinflammation, which is thought to drive the epileptogenic process. Although epilepsy exerts a heavy toll on the health, wellbeing and socio-economic outcomes of Africans, there are still major deficits in our understanding of how infections and inflammatory processes drive seizure development. Using the hippocampal organotypic brain slice culture model in mouse brains, I investigated the effects of classical immune activation on circuit excitability and cell viability. To initiate inflammation, I administered lipopolysaccharide (LPS), an endotoxin derived from gramnegative bacteria, and interferon-gamma (IFNy), a cytokine typically released by lymphocytes, to brain slices on varying time scales. I used enzyme-linked immune-sorbent assays to show that this reliably induced the release of the proinflammatory cytokines TNFα and IL-6 from the brain slices. I used patch-clamp electrophysiology to assess both the intrinsic electrical characteristics as well as the synaptic strength between pyramidal neurons after immune activation. I found no changes in the basic membrane properties of pyramidal neurons after short term neuroinflammation, but I did observe changes to the function of hippocampal networks at intermediate (24 hours) and lengthy (72 hours) time scales of immune activation in the form of significantly reduced spontaneous excitatory and inhibitory postsynaptic current frequencies and amplitudes. In addition, I developed an assay to determine neuronal survival to monitor the health of neurons in brain slices after immune activation and report that hippocampal organotypic brain slice cultures that were immuneactivated for 72 hours do not appear to experience either apoptotic or necrotic cell death. Taken together, these data constitute a valuable contribution towards understanding how inflammatory mechanisms drive changes to neuronal function, which could be relevant for understanding epileptogenesis in infectious and inflammatory causes of epilepsy.
dc.identifier.apacitationTinelli, S. (2021). <i>Exploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain</i>. (). ,Faculty of Health Sciences ,Department of Human Biology. Retrieved from http://hdl.handle.net/11427/36187en_ZA
dc.identifier.chicagocitationTinelli, Sasha. <i>"Exploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain."</i> ., ,Faculty of Health Sciences ,Department of Human Biology, 2021. http://hdl.handle.net/11427/36187en_ZA
dc.identifier.citationTinelli, S. 2021. Exploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain. . ,Faculty of Health Sciences ,Department of Human Biology. http://hdl.handle.net/11427/36187en_ZA
dc.identifier.ris TY - Master Thesis AU - Tinelli, Sasha AB - Epilepsy directly affects approximately 50 million people globally and is the most common neurological disorder in sub-Saharan Africa, mainly due to high rates of neuroinfections and head trauma experienced by people in the region. A common factor in these causes of acquired epilepsy is their association with significant neuroinflammation, which is thought to drive the epileptogenic process. Although epilepsy exerts a heavy toll on the health, wellbeing and socio-economic outcomes of Africans, there are still major deficits in our understanding of how infections and inflammatory processes drive seizure development. Using the hippocampal organotypic brain slice culture model in mouse brains, I investigated the effects of classical immune activation on circuit excitability and cell viability. To initiate inflammation, I administered lipopolysaccharide (LPS), an endotoxin derived from gramnegative bacteria, and interferon-gamma (IFNy), a cytokine typically released by lymphocytes, to brain slices on varying time scales. I used enzyme-linked immune-sorbent assays to show that this reliably induced the release of the proinflammatory cytokines TNFα and IL-6 from the brain slices. I used patch-clamp electrophysiology to assess both the intrinsic electrical characteristics as well as the synaptic strength between pyramidal neurons after immune activation. I found no changes in the basic membrane properties of pyramidal neurons after short term neuroinflammation, but I did observe changes to the function of hippocampal networks at intermediate (24 hours) and lengthy (72 hours) time scales of immune activation in the form of significantly reduced spontaneous excitatory and inhibitory postsynaptic current frequencies and amplitudes. In addition, I developed an assay to determine neuronal survival to monitor the health of neurons in brain slices after immune activation and report that hippocampal organotypic brain slice cultures that were immuneactivated for 72 hours do not appear to experience either apoptotic or necrotic cell death. Taken together, these data constitute a valuable contribution towards understanding how inflammatory mechanisms drive changes to neuronal function, which could be relevant for understanding epileptogenesis in infectious and inflammatory causes of epilepsy. DA - 2021_ DB - OpenUCT DP - University of Cape Town KW - Neuroscience LK - https://open.uct.ac.za PY - 2021 T1 - Exploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain TI - Exploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain UR - http://hdl.handle.net/11427/36187 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/36187
dc.identifier.vancouvercitationTinelli S. Exploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain. []. ,Faculty of Health Sciences ,Department of Human Biology, 2021 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/36187en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Human Biology
dc.publisher.facultyFaculty of Health Sciences
dc.subjectNeuroscience
dc.titleExploring the effects of classical immune activation on circuit excitability and cell viability in the mouse brain
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMSc
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