Scientists identify vital mechanisms controlling skin regeneration

WASHINGTON: The outer layer of skin, the epidermis, is constantly turning over to replace dead or damaged cells throughout our lifetime. Skin stem cells need to continuously make decisions: either make more copies of themselves (self-renewal) or switch their fate towards differentiation. The molecular mechanisms controlling this process remain poorly understood. Now, a research team has identified a molecular switch that plays an early and critical role in the skin stem cell differentiation process.

Even without sunburn, the outer layer of skin, the epidermis, is constantly turning over to replace dead or damaged cells throughout our lifetime. This epidermal layer provides an essential barrier for the human body, reducing water loss and combatingenvir on mental threats. Scientists are working to identify the molecular mechanisms controlling skin epidermal regeneration, but much remains poorly understood.

Now a Northwestern University research team has identified a molecular switch, through a protein called CDK9, that plays an early and critical role in the skin stem cell differentiation process. This switch is "off" in the stem cells. When the switch is turned on, a specific group of genes is immediately activated to trigger downstream gene regulators, allowing the skin cells to progressively gain barrier function. The findings have relevance for an improved understanding of cancer and wound healing, in addition to the fundamental understanding of skin regeneration.

"Skin stem cells need to continuously make decisions, to either make more copies of themselves -- a process known as self-renewal -- or to switch their fate towards differentiation. A delicate balance between these two decisions is crucial to maintain the integrity of skin and its barrier function," said Xiaomin Bao, a stem cell biologist at Northwestern who supervised the research. "We have discovered the switch bound to selected genomic regions inside the stem cells, ready to trigger the cell fate switch of initiating the stem cell's movement towards differentiation."

Bao is an assistant professor of molecular biosciences in the Weinberg College of Arts and Sciences and an assistant professor of dermatology at Northwestern University Feinberg School of Medicine. Her lab studies the fundamental biology of the process of skin stem cell differentiation.