Scientists Discover Why Multiple Sclerosis Damages Brain's Thinking Centers

Revolutionary Finding Changes MS Understanding

Multiple sclerosis researchers have uncovered a startling discovery that could transform how we treat this debilitating neurological disease. A team led by UC San Francisco, University of Cambridge, and Cedars-Sinai Medical Center now traces that loss to a breakdown in the DNA of neurons as inflammation overwhelms the brain. The breakthrough, published in Nature, reveals why the brain's gray matter—home to our higher thinking abilities—suffers damage even when treatments successfully protect the white matter that has long been the focus of MS therapy.

For decades, multiple sclerosis research has focused on myelin, the insulation around the brain's wiring. Scientists paid less attention to another loss that was happening in parallel: neurons in the cortex, the seat of higher thinking and cognition, were quietly dying. This parallel destruction explains why many MS patients experience cognitive decline and progressive disability despite treatments that effectively reduce relapses and new lesion formation.

The DNA Damage Discovery

The research team identified a specific type of brain cell— CUX2 neurons—the "canaries in the coal mine"—become overwhelmed by inflammation, losing their ability to fix genetic damage. In mouse models of MS, the researchers saw that inflammation sparked chemical reactions that damaged DNA in CUX2 neurons. These neurons, located in the brain's outer layers where complex thinking occurs, prove uniquely vulnerable to the inflammatory assault that characterizes MS.

The repair systems that protect these neurons from the stresses of development could no longer keep up; and this led to brain damage. Unlike the well-studied myelin damage that appears as white lesions on brain scans, this gray matter destruction occurs more subtly but with devastating consequences for cognitive function and long-term disability.

Clinical Implications and New Treatment Directions

"It's become clear that in addition to promoting remyelination in progressive MS, it's essential to find ways to directly protect gray matter neurons themselves," said Steve Fancy, Ph.D., DVM, a professor at the UCSF Weill Institute for Neurosciences. This finding suggests that current MS treatments, while valuable for preventing relapses, may be insufficient for halting the progressive aspects of the disease that cause permanent disability.

"The CUX2 neurons are like a 'canary in the coal mine' for the brain affected by MS," said David Rowitch, MD, Ph.D., deputy director for Research at Guerin Children's, professor of Pediatrics at the University of Cambridge, and co-corresponding author. "If we can protect these neurons, we might be able to contain the damage before the disease progresses."

A New Frontier in MS Research

"We can now point to a mechanism for why these vulnerable neurons in the brain are lost—DNA damage—and begin fighting MS on an entirely new front." The research opens possibilities for developing therapies that could directly protect neurons from DNA damage, potentially preventing the cognitive decline and progressive disability that current treatments cannot address.

This discovery represents a fundamental shift in understanding MS as more than just a disease of myelin damage. By revealing how inflammation destroys the brain's thinking centers through DNA damage, scientists now have a roadmap for developing treatments that could preserve cognitive function and prevent the irreversible neurological decline that makes MS so devastating. The next challenge lies in translating this knowledge into therapies that can protect these vulnerable neurons while they're under inflammatory attack.