title: Nerve-derived sonic hedgehog defines a niche for hair follicle stem cells capable of becoming epidermal stem cells.
abstract: In adult skin, stem cells in the hair follicle bulge cyclically regenerate the follicle, whereas a distinct stem cell population maintains the epidermis. The degree to which all bulge cells have equal regenerative potential is not known. We found that Sonic hedgehog (Shh) from neurons signals to a population of cells in the telogen bulge marked by the Hedgehog response gene Gli1. Gli1-expressing bulge cells function as multipotent stem cells in their native environment and repeatedly regenerate the anagen follicle. Shh-responding perineural bulge cells incorporate into healing skin wounds where, notably, they can change their lineage into epidermal stem cells. The perineural niche (including Shh) is dispensable for follicle contributions to acute wound healing and skin homeostasis, but is necessary to maintain bulge cells capable of becoming epidermal stem cells. Thus, nerves cultivate a microenvironment where Shh creates a molecularly and phenotypically distinct population of hair follicle stem cells.
authors.affiliation: Developmental Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA.
authors.forename: Isaac
authors.initials: I
authors.lastname: Brownell
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Guevara
authors.forename: C Brian
authors.initials: CB
authors.lastname: Bai
authors.forename: Cynthia A
authors.initials: CA
authors.lastname: Loomis
authors.forename: Alexandra L
authors.initials: AL
authors.lastname: Joyner
mesh_terms: D053687:Adult Stem Cells / Q000166:cytology / Q000378:metabolism*; D000818:Animals; D030801:Animals, Genetically Modified; D019070:Cell Lineage; D002470:Cell Survival; D054338:Cell Transdifferentiation; D002478:Cells, Cultured; D004817:Epidermis / Q000293:injuries / Q000502:physiology; D005786:Gene Expression Regulation; D055879:Gene Knock-In Techniques; D018859:Hair Follicle / Q000166:cytology / Q000502:physiology*; D053823:Hedgehog Proteins / Q000378:metabolism*; D051379:Mice; D039902:Multipotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D015513:Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D012038:Regeneration; D055153:Stem Cell Niche; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism; D019076:Transgenes / Q000235:genetics; D014945:Wound Healing; D000071676:Zinc Finger Protein GLI1
chemical_list: D053823:Hedgehog Proteins; D015513:Oncogene Proteins; D015534:Trans-Activators; D000071676:Zinc Finger Protein GLI1