When Space Shuttle Columbia exploded in 2003 upon reentry into Earth’s atmosphere, there were no human survivors. But while all seven crew members died in the disaster, a small petri dish of Caenorhabditis elegans — roundworms — was recovered in the weeks following the crash. Upon surprising analysis, all of the worms survived. Now, new research attempts to link the worms’ advanced endurance abilities with human stress responses, in order to better treat anxiety and posttraumatic stress disorder (PTSD).
In learning the mechanisms behind the roundworm’s neural reaction, scientists hope to find similar underlying behavior in humans — finally grasping, for instance, how certain people overcome stress seemingly in an instant, while others suffer crippling bouts of anxiety long after the trauma has passed.
“This type of research provides us necessary clues that ultimately could lead to the development of drugs to help those suffering with severe anxiety disorders,” Maureen Barr, professor of genetics at Rutgers University and member of a research team investigating nematodes’ reaction to stress, said in a statement.
In their study, Barr and her team tested the worms for several measures of environmental stress: heat shock, oxidative stress, hypoxia, and osmotic stress. Precisely, the team looked at six sensory nerve cells in the worm’s brain to see how the tree-like structures connecting the neurons, called dendrites, changed shaped when exposed to these stressors. The same structures exist in humans, and science has long known of their shape-shifting properties: under stress, the connections tend to weaken in some place and strengthen in others, narrowing a person’s range of cognition.
In worms, however, these connections have the unique ability to strengthen almost ubiquitously under intense stress. During the larval stage, C. elegans normally molts through four phases. When conditions become too harsh, the worms divert their normal molting pattern and enter an alternative larval stage called the dauer. In this form, the same one entered in the 2003 disaster, C. elegans can withstand extreme heat, starvation, and overcrowding.
“These worms that normally have a short life cycle turn into super worms when they go into the dauer stage and can live for months, although they are no longer able to reproduce,” Barr said.
What Barr and her team hope to uncover from this remarkable transformation is the process that takes place afterwards. Once the stressful episode passes, the strengthened connections prune back and the neural activity settles back into its baseline state. This behavior demonstrates the worm’s extreme resilience in the face of trauma, making it a prime candidate for Barr and other researchers to study against human responses.
Conditions such as PTSD and anxiety could see profound breakthroughs in medication and treatment methods if researchers can successfully harness the roundworm’s neural coping mechanism. So far the enzyme that researchers have pinned down is called KPC-1/furin. It provides essential bodily functions in humans, such as blood clotting, and in the worm it allows the larval morphing to take place.
Barr says the future for studying roundworms’ nervous systems could make for great leaps in therapeutics, and that understanding the worms’ molecular pathways may let scientists drill even further into the mysterious bedrock of mental illness and disorders.
Source: Schroeder N, Androwski R, Rashid A. Dauer-Specific Dendrite Arborization in C. elegans Is Regulated by KPC-1/Furin. Current Biology. 2013.