Scientists Find New Clues to Aging
Mutant Protein Involved in Premature Aging Condition May Also Play Role in Normal Aging
Focus on Progerin and Telomeres and Aging
In the current study, the scientists looked at millions of cells taken from seven healthy people, aged 10 to 92. They evaluated the cells in the lab for a year.
"We found the cells actually produce more and more mutant protein when they are getting old in vitro," Cao says. As the telomeres shorten, the end result is an accumulation of progerin, they found.
That of itself was not a huge surprise, she says.
The scientists knew that if progerin was being produced, the process of RNA splicing had to be in some way altered. RNA splicing refers to the way a cell processes genetic information when turning it into a protein.
''What we have shown here is that there is some way that short telomeres instruct the splicing apparatus to behave differently," Collins says. "It's an active process.''
The new research also indicates that these changes in the splicing occur when the gene is normal.
Once the telomeres become dysfunctional, they found, the splicing control is not working well.
The new research, Collins says, ''tells us the signal that comes from the shortened telomere that tells the cell to head for the exit [and die] is at least moderated by the turn on of the progerin."
Collins compares the effects of the shortening of telomeres and the production of progerin to different traffic signals that govern the life of a cell. ''If the [shortened] telomere is the yellow light, progerin turns it to red," he says.
Many questions are unanswered, he says. "We'd love to know what that signal is," he says. There may be other signals involved, he says.
Clues to Aging: Perspective
The new study ''gives us clues as to how we might study aging in everybody," says William Scott, PhD, professor of human genetics at the University of Miami's Hussman Institute for Human Genomics.
"They have shown that progerin plays a role in normal cellular aging," he says. What is yet to be found, he tells WebMD, is the importance of this protein in comparison to others involved in the process.
Scott says he would also like to know what role progerin levels play in different people as they age, he says. "Could this possibly explain the differences in how quickly people age?" he asks.