Shaggy-haired mice aid cell-aging research - Unexpected results hint at new ways of looking at stem

Steven Artandi, a Stanford cancer biologist, graduate student Kavita Sarin and colleagues reported today that a key component of the enzyme, known as telomerase, can switch on stem cells resting in mouse hair follicles.

The otherwise ordinary-looking mice promptly became as shaggy as '70s rock stars -- a wholly unexpected result that hints at new ways of understanding stem cell biology and age-related disorders.

It's unlikely to produce a baldness cure anytime soon, however. The mice had to be genetically engineered from birth to carry the special hair-growth machinery, Artandi noted during an interview.

"This doesn't present an immediate drug to treat male pattern baldness, definitely not," he said.

The experiments, reported in today's issue of the journal Nature, further burnish the Bay Area's status as a leading center of cellular-aging research.

Some of the main functions of the telomerase enzyme have been unraveled by scientists at UCSF, led by microbiologist Elizabeth Blackburn. Earlier work by Blackburn and others showed how telomerase can forestall the molecular machinery of aging by rebuilding protective DNA structures known as telomeres, found at the tips of chromosomes.

As most normal cells divide, these tips wear down, eventually signaling the cells it's time to die. Telomerase rewinds this molecular clock by rebuilding the tips, bestowing biological immortality on the cell. One of the hallmarks of fast-growing cancer cells is a ready supply of telomerase.

Blackburn wrote a commentary on the new research in the same science journal, suggesting there may be other roles for telomerase waiting to be discovered.

She also dug into the history books to address the possibility of telomeric hair tonics someday being touted on late-night TV.

"In ancient Egypt, men smeared their pates with hippopotamus fat in a desperate bid to stave off baldness," she said. "Is telomerase the new hippopotamus fat? Probably not. But this enzyme is already known to be vital in sustaining tissues in health and disease, and we should look beyond its eponymous function to understand the full spectrum of its potential roles."

The new research documents how one component of telomerase -- known as telomerase reverse transcriptase, or TERT for short -- affects stem cells in the skin, a function that appears to be independent of the enzyme's other roles in cancer and aging.

Stem cells, found in virtually all organs of the body, are the wellsprings of tissue regeneration. Specialized stem cells in the hair follicles cycle between a quiescent and active state. The timing of these cycles helps to regulate hair growth.

In the mouse studies, researchers found that the TERT molecule "can kick these resting stem cells into action," Artandi said
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