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Alzheimer’s disease (AD), a common form of dementia and an age related progressive neurodegenerative disorder, manifests as memory loss and reduced cognitive ability. One of the hallmarks of AD is formation of the Amyloid-beta 42 (hereafter Aβ42) plaques, which triggers oxidative stress due to aberrant signaling and finally results in the death of neurons. However, the exact mechanism causing cell death is still not well understood. We misexpressed high levels of human Aβ42 protein in the developing fly retina, which mimics AD like neuropathology. In a forward genetic screen, we identified members of highly conserved Wingless (Wg) signaling pathway as modifiers of the Aβ42 mediated neurodegeneration. Misexpression of negative regulator of Wg like Shaggy kinase (sgg) or a dominant negative form of Drosophila T-cell factor (dTCFDN5) or blocking Wg transport specifically by downregulating Porcupine (using porcupineRNAi) rescued Aβ42 mediated neurodegeneration by reducing the number of dying cells and restoring the axonal targeting from the retina to the brain. In order to determine the role of Wg in early vs late onset of AD, we have modulated our transgenic expression system to activate at different time points and will assess whether Wg is activated in all stages. It is also known that Wg induces cell death in the early eye developmental stage of Drosophila. We therefore want to understand by what mechanism and in which cells the Wg signaling is triggering cell death, whether it’s the Aβ42 misexpressing cells or the neighboring wild type cells. In order to approach this question we have developed a two clone system in our lab to understand the crosstalk between the two cell populations. We have shown that the wild type neighboring cells are undergoing cell death compared to the Aβ42 misexpressed cells. Data from the experiments will be presented.
Graduate Research - Graduate
Madhuri Kango-Singh, Amit Singh
Primary Advisor's Department
Stander Symposium project
"Understanding the role of Wingless (Wg) signaling pathway in Amyloid-beta 42 (Aβ42) mediated neurodegeneration in Alzheimer’s Disease" (2017). Stander Symposium Projects. 857.