La Jolla scientists’ genetics research using sea urchins may have ‘very big implications’ for human health

With implications reaching beyond the sea and into the human womb, researchers at UC San Diego’s Scripps Institution of Oceanography in La Jolla say they have achieved a breakthrough in genetics research using sea urchins.

The study, published June 6 in the journal Development, details the scientists’ success in creating a line of sea urchins whose genetic makeup is fully mapped and can be edited to study human disease genes.

Amro Hamdoun, a marine biologist at Scripps Oceanography and lead author of the study, said his lab is “interested in the different ways in which cells protect themselves from different kinds of stress in the environment” — their “chemical immunity system.”

Hamdoun, who has a background in cell and developmental biology, said sea urchins are useful for this sort of research because they produce large numbers of embryos that can be easily manipulated in the lab. That is beneficial for studying processes that happen in early life stages.

Additionally, sea urchins and humans share 70 percent of their genes.

Sea urchins have been used for 150 years as a model organism “to understand very fundamental things about how cells divide or how egg and sperm interact,” Hamdoun said.

Previously, sea urchins led to the discovery of a protein family known as cyclin that guides division of cells. That finding became a basis for current cancer treatments and earned cyclin’s discoverers a Nobel Prize.

Hamdoun’s lab has been using urchins to learn how cells eliminate toxins in food or the environment.

Until now, however, scientists “did not have a pathway for making stable genetic modifications” in sea urchins, he said. Previous gene editing lasted only a few hours.

“We spent the last couple of years … figuring out how to address that bottleneck to make basically genetic lines of sea urchins where certain genes have been modified, manipulated, knocked out so that we can better study their function.”

The process to determine the genome modifications involved use of the gene editing technology CRISPR and figuring out how to grow, genotype and propagate sea urchins, a change from previous methods of collecting urchins and then discarding them once research is finished.

The modified sea urchins are derived from the fast-growing species Lytechinus pictus, known as the painted sea urchin, which is common to Southern California.

Amro Hamdoun’s lab created a line of sea urchins whose genetic makeup can be edited to study human disease.

(Erik Jepsen / UC San Diego)

Growing sea urchins in his lab means Hamdoun can follow them for their entire life cycle, he said.

Now Hamdoun’s lab is able to study how the sea urchins “might regulate a disease process or a cellular process that we’re interested in for human health.”

“What we’re learning is that there are specific windows in the early life of animals where specific cells of the embryo are more or less sensitive to toxicants,” he said.

That has “very big implications for understanding how early life exposures in humans might affect later health” and lead to clinicians being able to predict a safe dosage of a drug for a pregnant woman or identify an unsafe level of environmental chemical exposure, he said.

The findings also open the door to biotechnological applications including how different types of contaminants in the ocean might affect human health.

“We can now envision making genetically modified lines of sea urchins that report the presence of a toxicant when it’s present in the water. … They can act as live biosensors of things that are in the environment,” Hamdoun said.

The study also means researchers across the country can use Hamdoun’s tools to study cell division, cancer pathways, reproduction and more.

Ecological implications include studying the ways that sea urchins home in on and overgraze kelp, Hamdoun said.

And for people interested in growing sea urchins for food, having a genetically enabled sea urchin “allows you to study the pathways that are responsible for growth and to understand how certain manipulations in aquaculture might improve the efficiency or growth rate or flavor or other features of the animal,” he said.

“This humble creature really has made a lot of contributions.”

Hamdoun said his lab is “starting to work on building additional genetic building blocks, [and] we’re, of course, continuing our own work [on] how does the early embryo and how do these early life stages protect themselves against the various kinds of stresses and challenges that they encounter.”

He said he hopes to reduce the harm caused by certain types of encounters “or perhaps even intervene in ways that are beneficial.” ◆