Watch Dr Prasad Paradkar accept the research grant award on behalf of A/Professor Heung-Chin Cheng and hear a bit about the project.
Project Summary:
Zika virus, a mosquito-borne virus, can infect mosquitoes when they feed on an infected human host. The infected mosquitoes then spread the virus to other human hosts through subsequent bites. If a pregnant woman is infected, she can pass the virus to her foetus during pregnancy and birth to cause severe birth defects in the infected infant. One of major defects is microcephaly where the infant’s brain shows signs of significant cell death and is much smaller than expected. Following the large outbreak in the Pacific and South Americas in 2015-2016, Zika virus infection has spread to more than 45 countries. With no approved vaccines and efficacious drugs to prevent the spread of the virus and to mitigate Zika virus-induced brain damage, the infection poses a huge public health risk with economic and social impacts. The World Health Organisation in 2018 classified Zika infection as a priority disease in urgent need of accelerated research to identify therapeutic targets for drug development.
Zika virus causes brain damage mainly by targeting a type of immature brain cells called neural progenitor cells (NPCs), which divide and mature to form multiple types of brain cells during foetal and infant development. Upon infection, Zika virus causes these cells to die with an unknown mechanism, leading to microcephaly. Our main objective is to employ a biochemical method called proteomics to investigate how Zika virus infection kills NPCs. Specifically, we aim to identify the proteins in NPCs that are chemically modified as a result of Zika virus infection. Their identification will (i) unveil how Zika virus infection skills NPCs and (ii) benefit the development of drugs to protect against cell death of NPCs in Zika virus-infected patients.
Outcomes:
Our first aim was to define the role of the newly discovered excitotoxicity-activated kinases in ZIKV-induced neuronal death using inhibitors of these kinases and the quantitative phosphoproteomic approach. We hypothesised that Zika virus infection induces excitotoxic neuronal death by aberrant activation of multiple protein kinases in neurons. Hypothesis vs findings: Our research revealed that: (i) multiple protein kinases are activated in neurons undergoing excitotoxic cell death and (ii) blockade of activation of one of the kinases Src can protect against excitotoxic neuronal death in vivo in a rat model of neurotoxicity.
Our second aim was to identify the substrates of NS2B-NS3 in ZIKV-infected NPCs and neurons, and we hypothesised that the proteomic method TAILS can identify the substrates and define the cleavage sites in the substrates of the Zika virus protease NS2B-NS3 in ZIKV-infected cells. The TAILS method allowed us to identify over 300 neuronal proteins cleaved by the excitotoxicity proteases in neurons undergoing excitotoxicity cell death. These findings indicate that TAILS can identify direct substrates of activated proteases in neurons.
From the results of the follow-up study and the findings described in Aims 1 and 2, we can (i) identify the cellular proteins that are proteolytically processed by NS2B-NS3 and/or calpains in Zika virus-infected cells and (ii) assign their synaptic locations and functions. The findings we made so far will contribute to our understanding of the pathophysiological mechanism governing cell death in Zika virus-infected neurons. More importantly, the cell-permeable Tat-Src peptide inhibitor and the neuroprotective CaMKIIα inhibitors developed by our collaborators are potential lead compounds for the development of neuroprotectants to reduce brain damage induced by Zika virus infection.
Outcomes submitted December 2021.
Publications:
Ameen SS, Dufour A, Hossain MI, et al. An Atlas of Phosphorylation and Proteolytic Processing Events During Excitotoxic Neuronal Death Reveals New Therapeutic Opportunities. bioRxiv 2020.06.15.151456. Published online June 15, 2020. doi:10.1101/2020.06.15.151456
The Brain Foundation is dedicated to funding the next generation of Australian research into brain disorders, diseases, and injuries, with the ultimate goal of advancing diagnoses, treatments, and patient outcomes.