Nova Southeastern University Researchers Discover DNA Repair is High in Heart, Nonexistent in Brain

Results Could Help Explain Causes of Dementia and Memory Loss

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Feb 09, 2015, 04:30 ET

FORT LAUDERDALE-DAVIE, Fla., Feb. 9, 2015 /PRNewswire/ -- Nova Southeastern University (NSU) researchers recently discovered that, contrary to prior belief, tissues of different mammalian organs have very different abilities to repair damage to their DNA.

These new findings indicate that the heart has the greatest capacity to repair its DNA, followed by the intestines, kidneys, spleen, testes, and lungs. The brain, however, exhibited no ability to repair damage to its DNA.

These studies were performed in murine cell tissue culture, but, based on previous human studies performed by the same investigators, such "tissue specificity" is true of humans, as well.

Using skin as the control, the researchers exposed growing cells derived from each of these tissues to a defined dose of ultraviolet (UVC) light, a part of normal sunlight, causing extensive DNA damage. Although there are five types of DNA repair performed by mammalian cells, the investigators then specifically measured the amount of repair performed by one type called nucleotide excision repair.

This type of DNA repair is a complicated process that requires a high level of metabolic investment by the cell. Brain cells may focus their energies on other more essential activities, and are not commonly exposed to UVC light, perhaps explaining their undetectable level of repair.

"The human body was not designed to live past 30 or 40 years, so our brains haven't prioritized DNA repair over other necessary functions," said lead investigator Jean Latimer, Ph.D., associate professor of pharmaceutical sciences, NSU's College of Pharmacy. "Our brains are frequently not physically prepared to last as long as medical science is now allowing our bodies to live. These findings could help explain a root cause behind memory loss and dementia."

The research team consisted of Latimer; Stephen Grant, Ph.D., associate professor of public health, NSU's College of Osteopathic Medicine; NSU College of Pharmacy students Vongai Majekwana, Pharm.D. candidate; and Yashira Pabon-Padin, Pharm.D. candidate; and Manasi Pimpley, Ph.D. candidate.

Their findings are published in the peer-reviewed journal, Photochemistry and Photobiology in an article titled "Regulation and dysregulation of mammalian nucleotide excision repair: a pathway to non-germline breast carcinogenesis." Read the full article at: http://onlinelibrary.wiley.com/doi/10.1111/php.12387/full.

Research reported in this press release was supported by the National Cancer Institute of the National Institutes of Health under award number R29CA71894.

The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

This study was also supported by the Ruth Estrin Goldberg Foundation and a President's Faculty Research and Development Grant from NSU.

About Nova Southeastern University: Situated on 314 beautiful acres in Ft. Lauderdale, Florida, Nova Southeastern University (NSU) is a dynamic research institution dedicated to providing high-quality educational programs at all levels. NSU is an independent, not-for-profit institution with approximately 26,000 students at campuses in Fort Lauderdale, Fort Myers, Jacksonville, Miami, Orlando, Palm Beach and Tampa, Florida as well as San Juan, Puerto Rico. NSU awards associate's, bachelor's, master's, specialist, doctoral and first-professional degrees in a wide range of fields. NSU is classified as a research university with "high research activity" by the Carnegie Foundation for the Advancement of Teaching, and it is one of only 37 universities nationwide to also be awarded Carnegie's Community Engagement Classification. For more information, please visit www.nova.edu. Celebrating more than 50 years of academic excellence!