How Worms Respond to Sleep Deprivation During Stress-Induced Sleep

Jessica using microscope

Students

2020
Engineering and Applied Sciences

Faculty

Wilf Family Term Assistant Professor of Bioengineering

Project Summary

This summer I worked in the Fang-Yen Lab in the Department of Bioengineering. Dr. Fang-Yen’s lab studies neurobiology, behavior, and aging in the roundworm Caenorhabditis elegans. My project specifically studied how worms respond to sleep deprivation during stress-induced sleep. C. elegans worms are useful model organisms because they have sleep states which are analogous to those in humans. One type of worm sleep is called lethargus, which is a PERIOD-regulated developmentally timed sleep analogous to cyclical PERIOD-regulated sleep in humans. The second is called stress-induced sleep (SIS) which occurs when the worm is exposed to a stressor; SIS is analogous to cytokine regulated sick sleep in humans. One important characteristic of a sleep state is that it is homeostatically regulated, meaning that sleep drive increases after sleep deprivation. Since homeostatic regulation has already been demonstrated in lethargus, our goal was to characterize homeostatic regulation of stress-induced sleep in C. elegans, in order to use it as a model of stress-induced sleep in all animals.

We studied extended sleep deprivation in SIS by exposing the worms to a heat stressor, then tickling them for an hour to deprive them of sleep. We then observed their subsequent sleep to see if worms that had been deprived of sleep fell into a deeper sleep than worms that were allowed to fall asleep normally. These results did not show evidence of a long-term homeostatic mechanism regulating SIS. Additionally, we studied brief sleep interruption of SIS. In these experiments, heat-stressed worms were exposed to brief blue light or vibrational stimuli to disrupt their sleep. These results showed that worms would have decreased movement following the disruptions, supporting that there is a short-term homeostatic mechanism regulating SIS.

Through my experience as a PURM student, I learned a lot about the research process. This was my first time working in a research lab, and I enjoyed learning how to handle and maintain the worms according to protocols, as well as planning and executing experiments. I learned the importance of being detail-oriented and documenting everything that happened over the course of an experiment. Also, working on this research project has contributed to my educational experience as a bioengineering student by exposing me to new types of biotechnology. Finally, I learned the need for patience in the research process; not everything we did over the summer was successful immediately, but it was always extremely rewarding to see results after spending time troubleshooting.