WASHINGTON — Scientists reported Thursday that they had identified an important new potential driver of aging, a finding that could have vast implications for human longevity and the treatment of diseases such as cancer, diabetes and Alzheimer's.
In studying the genetic mutations underlying Werner syndrome, an extremely rare genetic disorder that causes rapid aging, researchers discovered that the condition appears to lead to a disorganization in tightly packed bundles of DNA found in a cell's nucleus known as heterochromatin. This bundling acts as a switchboard for the gene's activity. When it is disrupted, it affects critical processes, resulting in a kind of cellular mayhem.
Previously, much of the research into the biological basis for aging had focused on mutations in DNA that may cause a deceleration or acceleration of the aging process and on telomeres, caps at the end of chromosomes that protect them from damage and appear to shorten as one gets older. This work has led to a gold-rush mentality among some entrepreneurs to create "anti-aging pills" or other magic bullets for aging, but most scientists in this field believe we are at least decades away from any practical treatments from this work.
Juan Carlos Izpisua Belmonte, a Salk Institute scientist and senior author of the paper, who collaborated with researchers at the Chinese Academy of Sciences, said the finding reported this week gives scientists another promising target.
The discovery is important for a field of biology known as epigenetics, which looks at how information not coded in DNA can affect disease. Scientists have found that chemical tags, called epigenetic marks, can cause genes to be turned on or off. Unlike genes, a person's epigenetics are affected by the environment and other external factors. In recent years, there has been animated debate about whether epigenetic changes resulting from an ancestor's traumatic childhood or happy adventures could be passed down through generations and, if so, how.
Belmonte said the discovery reported this week is likely to lead to techniques to manipulate epigenetic marks in a way that is similar to how we can now edit DNA through gene therapy.
"If we are artificially able to play around with these marks, we may be able to alter the process of aging," he said in an interview.
The paper, which was published in the journal Science, is the latest in a series of far-reaching findings about human biology made in recent years thanks to the availability of cutting-edge technology that allows us to tinker with and study ourselves at the most minute level.
"This is a beautiful example of how genomics, human stem cells and the new gene-editing technologies conjoin to provide major insights into human disease," said Rick Horwitz, executive director of the Allen Institute for Cell Science, who is on leave from his position as a professor at the University of Virginia. "This is an early example of what I suspect will be a very large number of similar kinds of studies."
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Stephen Kritchevsky, director of the Sticht Center on Aging at the Wake Forest Baptist Medical Center, said the work, which he called "quite remarkable," suggests that the heterochromatin may be more significant in aging than was previously appreciated. He pointed out that the study also looked at the bundling in younger and older patients and found that the DNA packaging of the older people looked similar to patients with Werner syndrome.
"This goes beyond a normal cell dish to substantiate the biological relevance of their findings," Kritchevsky said.