Mechanism discovered in worm defecation identifies potentially widespread cell-to-cell communication

The focus of two recent Nobel prizes, a species of roundworm has made possible another advance in the understanding of how cells talk to one another, according to a study published online Feb. 21 in the journal Current Biology.

In 2002, researchers won the Nobel Prize for Medicine for work in the roundworm Caenorhabditis elegans (C. elegans) on the genetics of how cells “decide” to self-destruct, a topic now central to human cancer research. Another team won in 2006 for the discovery in C. elegans of an ancient defense mechanism against attempts by viruses to disrupt cells’ genetic machinery.

In the latest worm-related news, today’s publication provides evidence of a new mechanism through which cells in the worm’s intestine signal for nearby muscle cells to flex by briefly making the area between them more acidic. Researchers believe that short-lived changes in acidity may have implications for cell signaling throughout the animal kingdom, from the sending of human nerve messages to worm defecation. The worm’s influence proceeds from the fact that its cells resemble human cells in many ways, but are easier to study.

“I worked with mammals during my training, but my research is focused now exclusively in worms,” said Keith Nehrke, Ph.D., assistant professor of Medicine within the Nephrology Division at the University of Rochester Medical Center, and corresponding author of the Current Biology study. “We don’t restrain or anesthetize the worms during our experiments, which allows us to study complex interactions between organs that only occur in eating, moving animals. It remains to be seen whether pH signaling is commonly utilized in man, but the potential impact is fantastic, as almost all biologic processes are regulated by acidity.”

Study Details

Theory holds that atoms are the building blocks of the universe. Atoms, in turn, are thought to be composed of energy bundles called electrons that orbit around protons and neutrons at the atom’s center. Furthermore, atoms exhibit a property called charge that explains their behavior. Like charges repel each other; opposites attract, and cells have harnessed these forces to drive life processes.

Some cellular machines work by pumping positively charged particles (e.g. calcium, sodium and potassium ions) into or out of cells. In some cases particles of like charge build up outside the cell, and are eager to rush back in if given the chance. That chance comes, under careful regulation, when cells open channel proteins in their outer membranes, enabling say calcium ions to enter. The charge flow is used as an energy source in some instances, and in others, as a biological switch to kick on life processes. Past studies have shown that the rhythmic wave of muscle contractions that push waste along the worm intestine is carefully regulated by signals captured in rising and falling levels of positively charged calcium ions.

What the current study found is that intertwined with calcium signaling may be a second mechanism, where positively charged hydrogen ions, also called protons, are employed to send signals.