New research suggests that certain types of brain cells may be "picky eaters," seeming to prefer one specific energy source over others. The finding has implications for understanding the cognitive decline seen in aging and degenerative diseases such as Alzheimer's and multiple sclerosis.
Studying mice, investigators from Washington University School of Medicine in St. Louis showed that a specific energy source called NAD is important in cells responsible for maintaining the overall structure of the brain and for performing complex cognitive functions. NAD (nicotinamide adenine dinucleotide) is a molecule that harvests energy from nutrients in food and converts it into a form cells can use.
The work appears in two journal articles in the May 8 issue of The EMBO Journal, a publication of the European Molecular Biology Organization, and in a recent issue of The Journal of Neuroscience.
"We are interested in understanding how cells make NAD and what implications that has for cellular function, especially in the context of aging and longevity," said Shin-ichiro Imai, MD, PhD, professor of developmental biology and of medicine and senior author of both papers. "We know, for example, NAD levels decrease with age in tissues such as muscle and fat. We wanted to find out if the same is true in the brain."
The investigators looked at two types of brain cells: adult neural stem cells, responsible for maintaining supplies of neurons and their supporting cells, and forebrain neurons, vital for performing complex cognitive tasks.
In The EMBO Journal, they reported that NAD levels decreased with age in the mouse hippocampus, a vital region of the brain for cognition. The researchers then used genetic techniques to find out what would happen when NAD manufacturing is turned off in the adult neural stem cells of the mouse brain.
"Neural stem cells are very metabolically expensive, so you might expect th
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Washington University School of Medicine