For the first time, functional hair follicles have been grown in cultured skin. Researchers behind the advancement say this project will be useful for studying mechanisms of hair follicle induction, evaluating new drugs for stimulating or inhibiting hair growth, and for modelling skin conditions.
Published in Cell Reports (Jan. 2, 2018), the paper describes how the investigators derived skin organoids, comprised of both epidermal and dermal layers, from a homogeneous sample of mouse pluripotent stem cells, and how those organoids spontaneously produce new hair follicles in a way that mimics normal embryonic hair development.
“The skin is a complex organ that has been difficult to fully recreate and maintain in culture for research purposes,” said senior author Karl Koehler, PhD, assistant professor of otolaryngology-head and neck surgery at the Indiana University School of Medicine in Indianapolis, in a press release. “Our study shows how to encourage hair development from lab grown mouse skin, which has been particularly troublesome for researchers to recreate in culture.”
In the cultured stem cells, the epidermal and dermal cells formed spheres—the organoids—with the epidermal cells on the inside, and the dermal cells on the outside.
The team identified the specific culture conditions that allowed these organoids to proceed through the stages of development much like skin in an embryo.
“After about 20 days, we were amazed to see that skin organoids sprouted hair follicles,” Dr. Koehler said. “The roots of the follicles protrude from the skin organoids in all directions.”
Researchers from Stanford University in Stanford, Calif., were able to confirm that the technique developed by Dr. Koehler and his team was reproducible with stem cells from other mouse strains.
“In addition to the major epidermal and dermal cell types we also found specialized cell types, such as melanocytes, Merkel cells, adipocytes, sebaceous gland cells, and hair follicle stem cells in organoids,” Dr. Koehler said. “This is fascinating because it shows that if we derive the basic building blocks of skin together in culture, then these diverse cell types will self-assemble on their own.”
Jiyoon Lee, PhD, a postdoctoral fellow in Dr. Koehler’s lab and lead author on the paper, said the findings are a blueprint toward building complete skin from stem cells, and might lead to reduced need for lab animals in research and improved quality of life for human patients with skin conditions.