Date of Graduation
School of Medicine
James W Simpkins
TNF-alpha is known to exacerbate infarct volume in animal models and elevated levels of TNF-alpha are correlated with worse outcomes in stroke patients. However, the mechanism is not well understood. TNF-alpha has been shown to be neurotoxic at high doses and after long exposure times which is not clinically relevant. Thus, we show for the first time that TNF-alpha at clinically relevant concentrations seen in the serum of stroke patients rapidly and profoundly decreases mitochondrial function resulting in neuronal cell death through activation of caspase 8 and cytochrome c release. A slight decrease in mitochondrial function is detrimental to neurons due to their high energy demand. Since TNF-alpha is known to be increased during ischemia and correlated with negative outcomes, it is important to understand the neurotoxic mechanism of TNF-alpha to develop potential therapeutic targets for stroke. Moreover, TNF-alpha is increased during infections, and 30-40% of strokes occur during an active infection. We show that having a stroke during an active bacterial infection mimic results in an increased infarct volume, worsened neurological deficits, and prolonged sickness behavior. TNF-alpha's rapid and profound effect on mitochondrial function may be one mechanism by which stroke severity is exacerbated, neurological deficits are worsened, and recovery delayed. Thus, enhancing mitochondrial function acutely post-stroke could be a potential therapeutic intervention.
Doll, Danielle N., "Role of Mitochondria in TNF-alpha Neurotoxicity in Stroke" (2015). Graduate Theses, Dissertations, and Problem Reports. 5502.