Investigating the Roles of DAPK, p53/CEP-1, and Mitochondrial Damage in Necrotic Neurodegeneration in C. elegans
Stroke is one of the leading causes of death in the U.S., with minority groups, suffering higher fatality rates. Stroke is caused by ischemia, where occlusion of blood supply to the brain results in neurodegeneration. Most of the damage is attributed to excitotoxicity, where an accumulation of the neurotransmitter glutamate in the synapse overstimulates postsynaptic neurons and ultimately leads to cell death (largely by necrosis). Stroke treatments are often ineffective, due to the delay between the onset of stroke and the delivery of effective treatment. To address this, we focus our study on putative later-acting mediators of excitotoxicity such as the Death-Associated Protein Kinase (DAPK). However, the mechanism of DAPK’s action, and the possible involvement of downstream effectors like p53, mitochondria, and CypD, remain unclear. We use the geneticallyaccessible nematode C. elegans as a model organism to study excitotoxic neurodegeneration due to the simplified-but-conserved version of key biological mechanisms that the nematode uses, and the strong combination of research tools this system offers. We propose that nematode excitotoxic necrosis culminates in functional mitochondrial collapse caused by DAPK-p53-CypD mediated mitochondrial Permeability Transition Pore (mPTP) opening. We combine transgenic and knockout nematodes to study the role of DAPK and its mediating partners such as p53/CEP-1, CypD/CYN-1, and the putative CypD-sequestering protein TRAP1/HSP-75 in C. elegans. We monitored neuronal necrosis and the effect of necrosis on p53’s subcellular localization. My preliminary results begin to suggest that HSP-75 mutation changes the level of neurodegeneration, but further analysis is needed. My preliminary fluorescent microscopy studies suggest that in some cases p53/CEP-1 can be found in the mitochondria of cells undergoing neurodegeneration. Ultimately, we hope that our research will provide a foundation for novel perspectives that could be later examined in higher animals for potential stroke therapeutics.
Neurodegeration, C.elegans, DAPK, p53, Stroke, Mitochondria, Biochemistry, Molecular and Cellular Neuroscience, Molecular Biology
City University of New York - City College
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