On the 1st of February, we were joined by two current Masters students, Lizzie English (MBiol) and Lydia Kitchen (MScR), who work in Paul Chazot’s lab at Durham University. As outlined by Lizzie, Despite dissimilar research topics, both students use the model organism Drosophila Melanogaster. As outlined by Lizzie, benefits of Drosophila as a model organism include its few ethical restrictions, short lifespan and easily modifiable genetics. Additionally, structures surrounding the brain (the skull and cerebrospinal fluid in humans) are closely paralleled in flies (the exoskeleton and haemolymph). This makes the fly a good model of neuro trauma.
Lizzie was first to discuss her 9-week project, entitled ‘Development of Drosophila model for repetitive concussions in sportspeople to evaluate a rational treatment for post-concussion syndrome (PCS)’. PCS is defined as concussion symptoms persisting for over three months after the initial head impact and is particularly problematic for rugby players, who face risks of early-onset neurodegeneration. This video (https://www.youtube.com/watch?v=AZBrLi608Z8) makes clear some of the reasons why a better understanding of PCS is important for developing potential treatment drugs.
To investigate PCS in the fly, Lizzie designed a device to deliver varying impact intensities to flies (see diagram). After the impact, she used a range of locomotion and biochemical assays to assess its effects. These included measuring how quickly treated flies were able to climb up a tube compared to control flies. Western blots look for markers of inflammation or axonal damage. Additionally, a survival assay records how many of the flies survived the trauma. Together, these assays provided insight into the efficacy of the fly as a model and allowed the optimal angle of release to be selected.
The second part of the project involved applying a test PCS drug and assessing whether this led to any outcome improvements, as measured through the aforementioned assays plus additional behavioural tests. We eagerly await the final results of these experiments! It was also very interesting to see how the project was carefully scheduled to maximise the quantity and quality of data collection over just nine weeks.
Secondly, Lydia Kitchen described her longer project, entitled ‘Photobiomodulation approach for COVID-19 treatment in Drosophila melanogaster: validation and mechanism’. The therapy involves using light wavelengths in the visible and near infrared spectra to penetrate tissues. It is thought that this may have neuroprotective effects, which could benefit COVID-19 patients since the disease is associated with a range of neurological symptoms, such as anosmia (loss of smell), delirium and stroke. Several pathways are thought to be involved. In particular, the absorption of light photons by mitochondria is known to lead to the activation of cytochrome c oxidase and commence a signalling pathway which alters mitochondrial functioning. To model the disease in Drosophila, Lydia plans to treat their food with the SARS-CoV-2 spike peptide; however, the project to date has focused on how the treatment affects WT controls, comparing light-treated to control-treated groups. Three assays have so far been used, assessing the flies lifespan curves, motor activity and the levels of reactive oxygen and nitrogen species. Future work will use biochemical assays to investigate how the SARS-CoV-2 spike peptide induces an immune response.