Using patient-derived stem cells and drug screening to unravel the mechanisms of astrocyte-induced DNA damage as a pathway for motor neurone death in

Lead Research Organisation: University of Sheffield
Department Name: Neurosciences

Abstract

Background: ALS is characterised by degeneration of motor neurons causing fatal muscle weakness and atrophy. Several in vitro and in vivo studies have demonstrated that astrocytes actively contribute to motor neuron loss in ALS (https://www.ncbi.nlm.nih.gov/pubmed/21908873). A number of studies have shown that this non-cell-autonomous mechanism involves soluble factors secreted by astrocytes as the exposure to growth medium from ALS astrocytes is sufficient to trigger motor neuron death (https://www.ncbi.nlm.nih.gov/pubmed/21832997). Although much research focuses on revealing the identity of astrocyte toxicity, a central question remains: What are the biological mechanisms taking place in motor neurons leading to their death? Recent cutting-edge research has shown that DNA damage plays a key role in motor neuron death in ALS (https://www.ncbi.nlm.nih.gov/pubmed/28714954).
Therefore our hypothesis is that ALS astrocytes can induce neurodegeneration by triggering DNA damage.

We aim to:
1 - Systematically determine whether human astrocytes from ALS patients carrying various disease-linked genetic mutations as well as sporadic can induce DNA damage in healthy and ALS human motor neurons (n=3 per patient group and healthy individuals). The student will learn cutting edge techniques such growing and differentiating stem cells as well as running Western blots, immunostaining and quantitative PCR to determine the presence of DNA damage in differentiated cells.
2 - Identify the pathways involved in this mechanism by manipulating the astrocytes or the motor neurones using gene therapy tools. We will suppress or overexpress specific candidates to assess their role in DNA damage in both cells types using viral vectors.
3 - Study a selection of tool compounds from AstraZeneca, our industrial partner, which can modulate the pathways involved in DNA damage identified in Aim 2.
The student will have the opportunity to spend 3 months at AstraZeneca in Cambridge to learn how to design, set up and analyse drug screening assays.

Translational implications: Considering that ALS astrocytes contribute to MN death through several mechanisms (https://www.ncbi.nlm.nih.gov/pubmed/25233402), understanding whether DNA damage is a central pathway in this process is of key importance. The translational implications are immediate, as several approved compounds targeting this pathway are available. Proving that enhancing DNA damage response in MNs is a primary defence mechanism is crucial for future therapeutic approaches.

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