Kewaunee Lecture: Skin Stem Cells: Coping With Stress

Abstract: Adult tissue stem cells have the ability to self-renew long term and differentiate into one or more tissues. Many stem cells are used sparingly to replenish cells during normal homeostasis. However, even stem cells that are quiescent must be able to respond quickly to injury in order to fuel rapid tissue regeneration. How stem cells balance self-renewal and differentiation is of fundamental importance to our understanding of normal tissue maintenance and wound repair. The regulatory circuitry governing this normal balancing act is must be intricately regulated in normal homeostasis, and then transiently altered to cope with injury responses. Increasing evidence suggests that these mechanisms go awry in inflammation and become hijacked in cancers.

Skin epithelium is an excellent model system to understand how stem cells remain quiescent during times of minimal wear and tear and how these cells become mobilized during the cyclical bouts of natural tissue regeneration that occur during hair growth. We've identified and characterized at a molecular level the skin's stem cells and shown that they reside in distinct niches that impart to the stem cells their behavior both in task and in the molecular properties they display.