Aging has long been assumed to be a passive consequence of molecular wear and tear, counteracted by the force of natural selection. But it's not so simple. Our discoveries have led to the realization that the aging process, like everything else in biology, is under exquisite regulation, in this case, by a complex, multifaceted hormonal system that affects aging in many species, including mammals. In 1993, we showed that changing a single gene in the small roundworm C. elegans can double its lifespan. This gene encodes an insulin/IGF-1 like receptor, which indicates that aging is regulated hormonally. By manipulating genes and cells, we have now been able to extend the lifespan and period of youthfulness of C. elegans by six times. We have found that signals from the reproductive system and sensory neurons influence lifespan. These signals act, at least in part, to control inslin/IGF-1 hormone signaling. These hormones influence the lifespan of the animal by coordinating the expression of a wide variety of subordinate genes, including antioxidant, stress response, antimicrobial, and novel genes, whose activities act in a cumulative fashion to determine the lifespan of the animal. Some of these subordinate genes can also influence the rate of onset of age-related disease. In this way, this hormone system couples the natural aging process to age-related disease susceptibility.
Cynthia Kenyon graduated valedictorian in chemistry and
biochemistry from the University of Georgia in 1976. She received her
PhD from MIT in 1981, where, in Graham Walker's laboratory,
she was the first to look for genes on the basis of their activity
profiles, discovering that DNA damaging agents activate a battery of
DNA repair genes in E. coli. She then did postdoctoral studies with
Nobel laureate Sydney Brenner at the MRC Laboratory of Molecular
Biology in Cambridge, UK, studying the development of
C. elegans. Since 1986 she has been at the University of California,
San Francisco, where she was the Herbert Boyer Distinguished Professor
of Biochemistry and Biophysics and is now an American Cancer Society
Professor. Her early work led to the discovery that Hox genes, which
were known to pattern the body segments Drosophila, also patterned the
body of C. elegans. These findings demonstrated that Hox genes were
not simply involved in segmentation, as thought, but instead were part
of a much more ancient and fundamental metazoan patterning system. In
1993, Dr. Kenyon's discovery that a single-gene mutation could
double the lifespan of C. elegans sparked an intensive study of the
molecular biology of aging. Dr. Kenyon's findings have now led to the
discovery that an evolutionarily-coserved hormone signaling system
controls aging in other organisms as well, including mammals. Kenyon
has received many honors, including the King Faisal Prize for
Medicine, the American Association of Medical Colleges Award for
Distinguished Research, the Ilse & Helmut Wachter Award for
Exceptional Scientific Achievement, and La Fondation IPSEN Prize, for
her findings. She is a member of the US National Academy of Sciences,
the American Academy of Arts and Sciences, and the Institute of
Medicine. She is now the director of the Hillblom Center for the
Biology of Aging at UCSF.
The lectures are given at 5.30 p.m. in The Lady Mitchell Hall, Sidgwick Avenue, with an adjacent overflow theatre with live TV coverage. Each lecture is typically attended by 600 people so you must arrive early to ensure a place.