Thesis defense Ator Ashoti: The DUX4 cytotoxic cascade, and CRISPR mitigation methods

Facioscapulohumeral muscular dystrophy (FSHD) is one of the most common muscular diseases worldwide. Patients often first suffer from weakened muscles in the face and around the shoulders, after which also the muscles in the upper arms, torso and sometimes the lower legs lose strength. The disease has a genetic component, meaning that it can be inherited or arise during embryonic development. Currently, FSHD is mostly treated using anti-inflammatory medication and physical exercise, but with limited effect on disease progression. Research into the molecular mechanisms underlying the disease is important to gain understanding about the disease and thereby develop better treatments.

FSHD model

During her PhD, Ator Ashoti therefore studied which molecular mechanisms become activated early in the course of disease of FSHD. “If we can intervene in the early stages, we can maybe prevent the activation of a whole cascade of mechanisms that cause damage,” Ashoti explains. During her research, she focused specifically on the gene DUX4, which plays a pivotal role in the development of FSHD if inappropriately activated. “Together with my colleagues, I developed a model in which we can switch DUX4 on or off at will using a substance called doxycycline. That way, we can study the consequences of DUX4 activation for the cells in the model.” As with FSHD, the active DUX4-gene in the model causes cell death.

New techniques to better study the mechanism

Among other things, the cell model has been used to study the RNA molecules in a cell – the transcriptome – after DUX4 activation. By mapping this, Ashoti hopes to contribute to the knowledge about the underlying mechanism of FSHD.

She also used the gene editing technique CRISPR-Cas9 to investigate if other genes play a role in the toxic cascade that is activated by DUX4. This turned out not to be the case, suggesting that there is no other gene that contributes much to DUX4 toxicity. “We therefore believe that the best way to inhibit FSHD is by efficiently disabling DUX4. New treatment approaches should focus on reducing or stopping the activation of this gene.

Social aspect

Ashoti considers the social aspect to be the highlight of her PhD. “The people at the Hubrecht are very open and friendly. I made a lot of friends and really had a great time.” However, her time in the lab was definitely not always as social. “I have also often worked individually and really became an independent researcher.”

She wants to encourage people who just started their PhD to take it easy in the beginning. “Don’t start working long hours straight away, you will be burned out in no time. There will be plenty of long days near the end of your trajectory, so take it easy while that is still an option.”

Hybrid defense

Ashoti defended her thesis on 17 June in hybrid form: a few people were allowed to be present and others viewed the ceremony via a livestream. She will continue her scientific career with a postdoc in Massimiliano Caiazzo’s lab at Utrecht University. There, she will develop a model for research into a rare form of Parkinson’s disease (dopamine transporter deficiency syndrome) that occurs in very young children.