First North American Planaria Meeting Held at Stowers

From left to right: Philip Newmark, PhD, Christian Petersen, PhD, Alejandro Sánchez Alvarado, PhD, Jochen Rink, PhD, Nestor Oviedo, PhD, Erica Smith, PhD, Peter Reddien, PhD,  Ricardo Zayas, PhD, Amy Hubert, PhD, Jason Pellettieri, PhD,  James Sikes, PhD, Labib Rouhana, PhD

In May, more than seventy planaria researchers gathered at the Stowers Institute to present their latest findings and discuss future directions for their work at the first North American planaria meeting. For the meeting’s organizer, Alejandro Sánchez Alvarado, PhD, a Howard Hughes Medical Institute and Stowers investigator, it was also a scientific family reunion.

Four generations of planaria researchers can trace their scientific pedigree to the day in 1997 when Phillip Newmark, PhD arrived from Spain with a thermos full of Schmidtea mediterranea to start his postdoctoral research in Sánchez Alvarado’s lab at the Carnegie Institution of Washington.

Planarians, tiny freshwater flatworms, had been known for centuries for their remarkable regenerative abilities. Yet they didn’t emerge as a recognized model system for the study of regeneration until Newmark and Sánchez Alvarado developed tools for studying gene function and visualizing stem cells in planarians.

“Failure was not something Alejandro ever considered,” says Newmark, now a professor who heads a lab at the University of Illinois at Urbana-Champaign. “He was always confident that it was a worthwhile endeavor and that we would make it work.”

Even when their whole planaria colony perished due to water quality problems Newmark and Sánchez Alvarado didn’t quit. Instead, they got on the next plane to Spain to collect new specimens in a little-known fountain in one of Barcelona’s public parks—a trip that over time not only took on an almost mythical aura, but also yielded all current lab strains of Schmidtea mediterranea.

“Back in the lab, this disaster provided the motivation to buckle down and spend nearly a year establishing a new colony derived from clonal lines,” remembers Newmark, also a Howard Hughes Medical Institute investigator.

A few years later, while a postdoc with Sánchez Alvarado, Peter Reddien, PhD, conducted the first RNA interference screen in planaria research. The method, which relies on small RNA molecules to suppress the activity of specific genes, allowed him to turn off the activity of hundreds of genes one by one. This effort is among the first unbiased regeneration genetic screens performed, which allowed investigators to zero in on the molecular mechanisms driving regeneration.

Reddien, a member of the Whitehead Institute for Biomedical Research in Cambridge, Massachussetts, and a newly selected Howard Hughes Medical investigator, describes those early days as a series of scientific and intellectual adventures driven by Sánchez Alvarado’s unceasing curiosity about the natural world. “We took a risk by studying planaria, but if you ask challenging biological questions, it is inevitable that something of impact will arise.”

Since these first pioneers started to poke and prod planarians with molecular tools, the field of planaria research has grown by leaps and bounds. Young scientists who trained with Newmark and Reddien have established their own labs and started to mentor the latest generation of students and postdoctoral students captivated by planaria’s regenerative powers.

“As a scientist, the way I see it, I’d rather be engaged in the discovery of new continents, rather than mapping those that have already been discovered,” says Sánchez Alvarado. “Planarians and regeneration offer vast, unexplored biological frontiers, fertile territories for discovery, and therefore for the expansion of human knowledge and understanding. Given the high caliber of the science discussed by the conference participants, it is clear to me that this group is meeting the challenge of discovery head on, and that the mysteries of regeneration will ultimately yield to their efforts.”