Haesun Kim

Defense for Nervous System Key to Healthy Function

 Understanding myelin may offer therapeutic benefits

Multiple sclerosis, Guillian-Barré syndrome and neuropathies related to diabetes and cancer chemotherapy produce debilitating effects—difficulty moving, fatigue and numbness, to name a few.

These progressive, degenerative disorders share another trait in common: they all show evidence of having lost some of the nervous system’s natural protection, known as myelin. Formed as an insulator to wrap around nerve cells, myelin protects their functioning and survival. It is essential for rapidly conducting electrical signals to muscles.

When myelin breaks down or is destroyed, a process called demyelination, the impact can be significant and permanent.

“If you lose myelin structure, you lose the normal function of the nervous system. It affects motor skills and you can have pain,” says Haesun A. Kim, associate professor in the Department of Biological Sciences at Rutgers-Newark. Kim and her laboratory are looking for biological signals that trigger demyelination. “We think there are actual signals that tell myelin-forming cells to break down the myelin.”

“We’re trying to identify the mechanism,” she adds. “Our hope is that once we identify the signal, we can target how to prevent it from happening. That’s a long-term goal.”

Kim’s group has worked for several years on exploring myelin formation and loss in the peripheral nervous system or PNS. These nerves are found outside the brain and spinal cord, which comprise the central nervous system or CNS.

A 2012 study published by Kim and her colleagues in The Journal of Neuroscience looked at the molecular mechanisms at work in causing myelin breakdown when an enzyme—a protein kinase—is activated after peripheral nerve damage. Kim’s group has an on-going project showing that the kinase signal functions in the CNS as well. 

She and her laboratory also have investigated growth factor signals, finding that a soluble form of a growth factor helps myelin-forming cells function in the PNS. “We hope it will also improve myelin repair after loss,” she says.

Some work has moved into CNS processes. Kim currently is looking at what happens to myelin during traumatic brain injury (TBI). In TBI, a blow to the head causes the brain to move rapidly, hit the skull and become damaged—such as in a football injury or car accident. The movement stretches long nerve cells called axons, which carry electrical signals from neurons, nerve cells in the brain.

To find out how TBI demyelination begins, Kim is using an axon-stretching model system created by Bryan J. Pfister, an associate professor of biomedical engineering at the New Jersey Institute of Technology (NJIT). Working collaboratively with Pfister, Kim is stretching a myelinated axon culture to identify the signal causing myelin breakdown. “We want to see if we can minimize damage,” she says.

Such research keeps Kim and her laboratory actively engaged in identifying and exploring the mechanisms behind myelin changes. That may someday help those affected by neurodegenerative diseases.

“Any new finding is exciting,” she says.

Biograph y
Following completion of her undergraduate work in horticulture at Seoul National University in Seoul, Korea, Haesun A. Kim came to the University of Toledo in Ohio, where she received her M.S. in biology. Kim earned a Ph.D. in cell biology, neurobiology and anatomy at the University of Cincinnati. During that time, she developed her interest in exploring Schwann cells, which form myelin in the peripheral nervous system. Kim was a postdoctoral research fellow in cell biology and neurobiology at the Dana-Farber Cancer Institute, Harvard Medical School, where she investigated cell response mechanisms in nerve injury and demyelination. Arriving at Rutgers-Newark in 2004 as an assistant professor of biology, she became an active researcher and mentor to doctoral students and junior faculty. In 2010, Kim was named associate professor. She has been, or is, principal investigator for studies funded by the National Institutes of Health, New Jersey Commission on Brain Injury Research, New Jersey Commission on Spinal Cord Research, and others.

Media

NJ doctors unlock secrets to traumatic brain injuries
New Jersey Monthly - Oct 14, 2008

One Father's Crusade
New Jersey Montly  -  Oct 14, 2008

Critical Knowledge About The Nervous System Uncovered By...
Medical News Today - Nov 7, 2007

Selected Publications  (Kim and co-authors)