Inside Salk; Salk Insitute

Deciphering the Glial Code

Physicist/Neuroscientist Axel Nimmerjahn to join Salk's Waitt Advanced Biophotonics Center

Axel Nimmerjahn

Axel Nimmerjahn

A group of cells living in the same "neighborhood" do not necessarily speak the same "language." Such is the case in our brains, between neurons, the cells that electrically transmit information, and their supportive neighbors, glial cells. Yet, glia intricately communicate with neurons to somehow ensure that our nervous system functions properly. So just how do glia function?

Physicist-turned-neuroscientist Axel Nimmerjahn has been intrigued by this scientific problem since first encountering glial cells during his graduate studies at the Max Planck Institute for Medical Research in Heidelberg, Germany. Deciphering glial cells' enigmatic language, and their role in contributing to a functioning brain, both in its healthy and diseased states, will be his lab's aim when he joins the Salk Institute as assistant professor in the Waitt Advanced Biophotonics Center, funded by a $20 million grant from the Waitt Foundation, on Nov. 1.

Nimmerjahn will use the latest in light microscopic tools, some of which he developed during his postdoctoral studies at Stanford, to dive deep into tissue of lab models to visualize glia and other cells in action. The results of his research could have implications in developing possible treatments for many diseases, he says.

"We know that glial cells are critically involved in many injuries and diseases, but it's unclear at this point what their specific contribution is to each one of them, Nimmerjahn says. "In some cases like glioma (tumors in the nervous system), they appear causal, yet in others they undergo reactive changes. But even if they are not the source of the actual disease, given their essential supportive role and potential to undergo reactive changes, glia can profoundly influence disease progression and regeneration.

"So this is why it is critically important to define the role of glial cells in health and disease. If we better understand these cells, then hopefully we can come up with a treatment that targets and tweaks them," he says. "In a number of diseases, protecting or restoring glial cells' supportive function may turn out to be a more effective neuroprotective strategy than targeting neurons itself."

Among the important discoveries his group made was demonstrating that microglia, a type of glial cell that protects our brains from foreign material, don't stand idly by, as was once thought. They found that in healthy brains the cells are in fact continually on patrol to remove potentially harmful substances and react instantly to disruptions of the blood-brain barrier.

With a multidisciplinary team at Stanford he developed miniature epifluorescence microscopes, measuring about 1 cubic centimeter in size and weighing less than 2 grams, that enabled him to take the first-ever optical recordings from glia and neurons in freely behaving mice. Using his novel techniques, he also provided evidence that glial cells might be more than just support cells.

Nimmerjahn's work will lend itself to collaborations with a wide range of scientists at the Salk Institute. "Salk is a highly collaborative place, which makes for a perfect scientific environment, and, of course, the support of the new Waitt Advanced Biophotonics Center is just amazing," Nimmerjahn says. "This is a great opportunity to add a new level to the biological projects that are really excellent at the Salk."