Current Research

Our major focus is to understand how stem cells sustain organ regeneration using the mouse hair follicle as a model system. Every day our body loses billion of cells, which are replenished through a continuous regeneration of many of our tissues. This process is sustained by the presence of stem cells, which act as a lifelong reservoir by their ability to self-renew and differentiate in all the different lineages of a tissue. Importantly, the stem cell environment, called the niche, maintains the special properties of stem cells and regulates their behavior. Despite several recent advances, the genetic and molecular basis by which stem cells and their niche can sustain regeneration is still poorly understood.

Our laboratory uses the hair follicle because of its continuous regenerative abilities. We have developed tools that allow us to 1) identify the signals that trigger stem cell activation at the beginning of a new hair growth, 2) understand how stem cells exit the niche to sustain hair regeneration, and 3) determine the potential breath for hair follicle stem cells. Employing genetics, molecular biology and microscopy both in vitro and in vivo will allow us to uncover basic principles of how vertebrate organs sustain regeneration. Our long-term goal is to understand whether these basic principles of normal organ regeneration can shed light on which cells and signaling pathways go awry during tumorigenesis.

Figure Legend: The hair follicle stem cell niche contains two epithelial compartments (dashed line) and a mesenchymal one (continuous line). The bulge (marked in green), contains the bona fide epithelial stem cells, and the hair germ (marked in red), contain the epithelial progenitors that initiate a new round of regeneration. The mesenchymal dermal papilla compartment is located at the bottom of the epithelial compartments and it functions as a signaling center. All nuclei are marked in blue.

Representative Publications

Greco Valentina*, Chen Ting*, Rendl Michael, Pasolli Amalia, Stokes Nicole and Fuchs Elaine. 2009. “ A Two-Step Mechanism for Stem Cell Activation during Hair Regeneration”. Cell Stem Cell, Feb 6; 4:1-15.

Jinsong Li*, Greco Valentina*, Guasch Geraldine*, Mombaerts Peter and Fuchs Elaine. 2007. “Mice cloned from skin cells”. PNAS, Feb 20;104(8):2738-43.

Tumbar Tudorita, Guasch Geraldine, Greco Valentina, Blanpain Cedric Lowry William, Rendl Michael and Fuchs Elaine. 2004. “Defining the epithelial stem cell niche in skin”. Science, Jan 16;303(5656):359-63.

Greco Valentina, Hannus Michael and Eaton Suzanne. 2001. “Argosomes:  A Potential Vehicle for the Spread of Morphogens through Epithelia”. Cell, Sep 7;106(5):633-45.

Contact Information:

Email: valentina.greco@yale.edu

Lab Website: http://www.yale.edu/grecolab/