Our tissues are in a constant state of flux — cells are lost and cells are generated, with local signals and stem cells maintaining the balance, said Roel Nusse, Ph.D., during last week’s Flexner Discovery Lecture.
Nusse, the Virginia and Daniel K. Ludwig Professor of Cancer Research at Stanford University School of Medicine, discovered one of the signals, the protein Wnt1, in 1982. Since then, he has focused on Wnt signaling, which has roles in all aspects of development and controls the function and maintenance of tissue stem cells — cells that replicate themselves and generate new cells for tissues. Aberrant Wnt signaling – because of mutations in Wnt signaling components — is implicated in cancer.
Nusse described novel tools his laboratory has developed to study Wnt signaling. One set of tools allows his team to track the fate of Wnt-responding cells over time, in vivo. He and his colleagues have identified a dedicated stem cell population in the liver — the first stem cells in the liver — and have characterized a stem cell niche around the central vein.
Using purified Wnt immobilized to microscopic beads, Nusse and his team also are exploring the role of Wnt in the asymmetric cell division of stem cells. Stem cells divide to produce a new stem cell and a daughter cell that will go on to differentiate (mature) into a tissue cell.
“Localized Wnt promotes two different cell fates at the same time — self-renewal, but also differentiation,” Nusse said.
Nusse is an investigator of the Howard Hughes Medical Institute and a member of the National Academy of Sciences.
Nusse was the CDB Distinguished Speaker, sponsored by the Department of Cell and Developmental Biology. The Cell and Developmental Biology Distinguished Faculty Lecture Series is an annual event in honor of the more than 80 years of excellence in research, teaching and service by the faculty of the department.
For a complete schedule of the Flexner Discovery Lecture series and archived video of previous lectures, go to www.mc.vanderbilt.edu/discoveryseries.
