Sarah E. Millar, Ph.D.
Associate Professor, Dept of Dermatology and Cell & Dev Bio

Developmental, Stem Cell and Regenerative Biology Program

Address

office
M8D Stellar-Chance Labs
422 Curie Blvd
Philadelphia PA 19104-6100
215 898-2633

lab
M8D Stellar-Chance Labs
422 Curie Blvd
Philadelphia PA 19104-6100
215 898-1818

Fax: 215 573-9102
E-mail: millars@mail.med.upenn.edu

Link(s)

Sarah Millar at the Dept of Dermatology

Education

Cambridge University, B.A. (Natural Sciences), 1982

University of London, Ph.D.(Molecular Biology), 1987

Research Interests

• Development of hair follicles, mammary glands, taste papillae and teeth; hair follicle and mammary gland stem cells; skin and mammary gland tumorigenesis; microRNA functions in embryonic and postnatal skin and mammary glands.

Key words: hair, stem cells, skin, tooth, mammary gland, mouse, Wnt, Bmp, beta-catenin, Dicer, miRNA.

Description of Research

Our research is focused on understanding cell-cell signaling mechanisms controlling development and stem cell function in organs such as hair follicles, mammary glands, taste papillae and teeth that arise from embryonic ectoderm (ectodermal appendages). We have shown that WNT/beta-catenin signaling is required for initiating the formation of hair follicles, mammary glands and taste papillae from multipotent cells in the embryonic surface ectoderm. We are using genetic gain and loss of function and microarray approaches to identify direct targets of this pathway in developing hair follicles. We are also interested in understanding the roles played by WNT/beta-catenin signaling in regulating stem cell function, differentiation and tumorigenesis in the adult. For these studies we have developed inducible systems for expression of Dickkopf1 (a potent secreted WNT inhibitor), deletion of the WNT effector beta-catenin, and expression of an activated form of beta-catenin, in the epidermis and hair follicle, tooth, tongue and mammary gland epithelia in postnatal mice. We are using these mouse models to determine the effects of gain and loss of WNT/beta-catenin signaling on hair follicle stem cells and postnatal hair growth; mammary stem cells and postnatal mammary gland development; tooth development and dental stem cells; taste papilla function; and skin and mammary gland tumorigenesis. We are also using genetic approaches to identify WNT ligands and receptors required for appendage development, and to investigate the roles played by non-beta-catenin mediated WNT signaling in the skin. Finally, we have shown that deletion of the miRNA processing enzyme Dicer causes major defects in hair follicle development. We are studying the functions of Dicer and miRNAs in the formation and maintenance of hair follicles and mammary glands.

Recent Publications

Andl, T., Reddy S. T., Gaddapara, T. & Millar, S. E. (2002). WNT signals are required for the initiation of hair follicle development. Developmental Cell, 2, 643-653.

Andl, T., Murchison, E. P., Liu, F., Zhang, Y., Yunta-Gonzalez, M., Tobias, J. W., Andl, C, D., Seykora, J. T., Hannon, G. J., Millar, S. E. (2006). The miRNA processing enzyme Dicer is essential for the morphogenesis and maintenance of hair follicles. Current Biology 6, 1041-9.

Liu, F., Thirumangalathu, S., Gallant, N. M., Yang, S. H., Stoick-Cooper, C. L., Reddy, S. T., Andl, T., Taketo, M. M., Dlugosz, A. A., Moon, R. T., Barlow, L. A., Millar, S. E. (2007). Wnt-beta-catenin signaling initiates taste papilla development. Nat Genet. 39, 106-12.

Liu, F., Chu, E. Y., Watt, B., Zhang, Y., Gallant, N. M., Andl, T., Yang, S., Lu, M-M., Piccolo, S., Schmidt-Ullrich, R., Taketo M. M., Morrisey, E. E., Atit, R., Dlugosz, A. A., Millar, S. E. (2008). Wnt/beta-catenin signaling directs multiple stages of tooth morphogenesis. Dev. Biol. 313, 210-24.

Zhang, Y., Andl, T., Yang, S. H., Teta, M., Liu, F., Seykora, J. T., Tobias, J. W., Piccolo, S., Schmidt-Ullrich, R., Nagy, A., Taketo, M. M., Dlugosz, A. A., Millar, S. E. (2008). Activation of beta-catenin signaling programs embryonic epidermis to hair follicle fate. Development 135, 2161-72.

Search PubMed for more articles

Lab

Rotation Projects

1. Global approaches to identify direct Wnt target genes in developing hair follicles
2. Functions of miRNAs in maintaining hair follicles and hair follicle stem cells
3. Functions of miRNAs in mammary gland development
4. Non-canonical Wnt signaling in the skin

Lab personnel:

Fei Liu, PhD: Postdoctoral fellow
Yuhang Zhang, PhD: Senior Research Investigator
Xinjiang Wu, PhD: Postdoctoral fellow
Yeon-Sook Choi, PhD: Postdoctoral fellow
Zofeyah MacBrayer: PhD thesis student
Monica Teta: PhD thesis student
Matthew Crump: undergraduate student researcher