Hair, mice, and how cells regenerate

The human body loses billions of cells every day, but its self-renewing supply of stem cells, which can become any type of tissue, continuously replace those lost cells. Researchers, however, understand little about how this regeneration is sustained. Valentina Greco, Ph.D., associate professor of genetics, of cell biology and of dermatology, and principal investigator at Greco Lab, wants to get to the bottom of it.

What enables normal tissue, which can harbor mutated cells, to continue to regenerate as healthy tissue and not become cancerous? Greco looks for the answer in hair follicle stem cells in their niche—the microenvironment in which stem cells live. She studies them in the skin of live healthy mice.

Greco and her colleagues Ann Haberman, Ph.D., assistant professor of laboratory medicine and of immunobiology, and David Gonzalez, M.H.S., a research associate at Yale’s In Vivo Imaging Facility, adapted two-photon fluorescence microscopy to visualize cells in live mice. Greco can tag the cells she wants to follow in fluorescent transgenic mice, and track them throughout their life cycle. Observing these cells in their natural environment, Greco hopes to identify the choices and behaviors of stem cells that sustain normal tissue function even when mutations are present.

A better understanding of normal cell regeneration could help researchers predict when something will go wrong. “We could capture the initiation of cancer and understand how it emerges from normal tissue growth,” Greco said. “This has tremendous potential for cancer prevention.”