Studying cells that aid memory, learning and mood

Grigori Enikolopov — or Grisha to his colleagues — is involved in pushing limits. The associate professor at Cold Spring Harbor Laboratory and member of the graduate program at Stony Brook University is developing ways to refine state-of-the-art imaging to see the creation of new brain cells in adults.

The cells he’s seeking to observe are stem cells located primarily in the hippocampus. In animal models, these stem cells have the potential to restore memory after an injury or disease, enhance mood or improve the ability to learn.

“His latest work is very bold in trying to refine imaging” to be able to observe in real time “the generation of new brain cells,” said Dennis Steindler, the Joseph J. Bagnor/Shands Professor of Medical Research in the Department of Neurosurgery at the University of Florida. Steindler, who has known Enikolopov for over a decade, said his Cold Spring Harbor Laboratory colleague is “pushing the limitations of imaging. We’re at the point where we’re going to see what the resolution limit of noninvasive imaging of a brain is, anatomically and molecularly.”

Enikolopov and Steindler also led a study that will help prepare astronauts push the limits of space travel on potential future trips to Mars. The scientists explored the effects of cosmic radiation on these same important stem cells. They discovered that inactive stem cells are vulnerable to the effect of prolonged periods in space.

Working with Marcelo Vazquez at Brookhaven National Laboratory among others, the group discovered that these neural stem cells were sensitive to cosmic radiation. This finding, which was published in 2008, will help NASA with future missions that could involve prolonged exposure to cosmic radiation.

“Space travel in the future will use the data that [Enikolopov] and my collaborators helped develop to provide better protection methods for astronauts taking long space trips,” Steindler said. “It speaks to the breadth and scope of [Enikolopov’s] research” that he could become an instrumental part of this team.

Indeed, Enikolopov is interested in a broad range of areas related to stem cells, including understanding the signals that activate these powerful cells that can become neurons or glial cells, which are critical for the functioning of neurons in the brain.

Up until about 20 years ago, scientists didn’t even know stem cells were located in the hippocampus. Only recently were researchers like Enikolopov able to demonstrate the connection between stem cells and new neurons, learning, memory and mood.

“The idea that new neurons may be important for new memories was a natural and intuitive one, but it took a while to prove that,” Enikolopov said.

Steindler called Enikolopov “a rare scientist who has a grasp on many different complex technological approaches,” and said his Cold Spring Harbor collaborator has helped make important discoveries.

Enikolopov said stem cells are often involved in helping recover from damage to the brain. He and other scientists don’t yet know how these stem cells assess and repair the damage. As people age, the number of new neurons produced decreases, which means each of the stem cells adults have becomes more important at warding off age-related cognitive declines.

“Preventing the birth of new neurons from stem cells in the adult brain causes problems with memory; conversely, increasing production of new neurons enhances memory,” he said.

In animal models, running and living in an enriched environment increases production of new neurons. With humans, scientists still have to prove that, although Enikolopov believes that people should also benefit from exercise and experiencing new environments and ideas.

If Enikolopov and Steindler are effective, they may some day help “make 80 the new 40,” Steindler said.

While Steindler is an enthusiastic supporter and collaborator, he isn’t the first American scientist to appreciate the talents of the Russian-born Enikolopov. James Watson, the Nobel Prize-winning former director of CSHL, was visiting the institute in Moscow where Enikolopov worked. Watson invited him to become a visiting scientist at Cold Spring Harbor Laboratory.

Enikolopov understood his appointment would last around a year. “We thought this would be temporary” when he and his wife, Natalia Peunova, an independent research investigator at Cold Spring Harbor Laboratory, left Russia. That was a quarter of a century ago, as the couple raised three children on Long Island and have two grandchildren.

Enikolopov enjoys driving along the North Shore, where he marvels at the water views.

As for his work, Enikolopov is hoping to unlock the stem cell code. The primary focus is on “understanding how stem cells produce new neurons and how they talk to other types of stem cells,” he explained.