Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells
Luis A. Garza, … , John W. Tobias, George Cotsarelis
Luis A. Garza, … , John W. Tobias, George Cotsarelis
Published January 4, 2011
Citation Information: J Clin Invest. 2011;121(2):613-622. https://doi.org/10.1172/JCI44478.
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Research Article Dermatology

Bald scalp in men with androgenetic alopecia retains hair follicle stem cells but lacks CD200-rich and CD34-positive hair follicle progenitor cells

Abstract

Androgenetic alopecia (AGA), also known as common baldness, is characterized by a marked decrease in hair follicle size, which could be related to the loss of hair follicle stem or progenitor cells. To test this hypothesis, we analyzed bald and non-bald scalp from AGA individuals for the presence of hair follicle stem and progenitor cells. Cells expressing cytokeratin15 (KRT15), CD200, CD34, and integrin, α6 (ITGA6) were quantitated via flow cytometry. High levels of KRT15 expression correlated with stem cell properties of small cell size and quiescence. These KRT15hi stem cells were maintained in bald scalp samples. However, CD200hiITGA6hi and CD34hi cell populations — which both possessed a progenitor phenotype, in that they localized closely to the stem cell–rich bulge area but were larger and more proliferative than the KRT15hi stem cells — were markedly diminished. In functional assays, analogous CD200hiItga6hi cells from murine hair follicles were multipotent and generated new hair follicles in skin reconstitution assays. These findings support the notion that a defect in conversion of hair follicle stem cells to progenitor cells plays a role in the pathogenesis of AGA.

Authors

Luis A. Garza, Chao-Chun Yang, Tailun Zhao, Hanz B. Blatt, Michelle Lee, Helen He, David C. Stanton, Lee Carrasco, Jeffrey H. Spiegel, John W. Tobias, George Cotsarelis

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Figure 2

Preservation of KRT15hi hair follicle stem cells in bald scalp, but depletion of CD200hiITGA6hi and CD34hi progenitor cells.

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Preservation of KRT15hi hair follicle stem cells in bald scalp, but depl...
Pseudocolor dot plots (A, B, D, E, G, and H) or overlay graphs (C, F, and I) from FACS analysis of epithelial cells stained with the indicated antibodies. Overlay graphs are plotted first with cells from haired scalp, then layered over with cells from bald scalp. (A–C) Representative example showing KRT15hi cells preserved in bald scalp (n = 8, P = 0.3). In contrast, a defined population of CD200hiITGA6hi cells (D–F; n = 9, P = 0.005) and CD34hi cells (G–I; n = 3, P = 0.011) were depleted in bald scalp. Numerical values represent percent cells in the gated population, of all cells plotted in the representative experiments.