The new resource is called Hair-GEL (gene expression library) and relies on the fundamental genetic principle that a blueprint for developing tissues is encoded by genes that are differentially activated in specific cell types.
The research team claim that the work, which is published in the journal Developmental Cell, is central to understanding the interactions between stem cells and their environment, as initial analyses take a molecular snapshot of stem cells and niche cells as they interact to form hair follicles.
"We know these cells are important for coordinating hair growth, but we don't know how they communicate on a molecular level to achieve such a complex process,” says senior study author Michael Rendl, MD, Associate Professor in the Department of Developmental & Regenerative Biology at Mount Sinai.
“Our goal in publishing this database is to construct a launching pad for future studies that will clarify the role of all signals driving this developmental program -- with the ultimate goal of transitioning this knowledge to the clinical setting.”
In their work, the Mount Sinai research team used next-generation RNA-sequencing to compare all RNA molecules in embryonic skin cells to uncover hundreds of genes that are active as skin develops, including those that guide the formation of hair follicles.
By doing this, the scientists uncovered unique genes associated with each one, called ‘gene signatures’, in turn revealing the messages specific cell types send and receive as they communicate and cooperate to form skin and all of its complex compartments.
"While this work provides the first high-resolution molecular study of hair follicle precursor cells, its true power comes from analysing these cells in the context of the entire developing skin," adds lead study author Rachel Sennett.
The authors confirm the activity of defined signaling pathways, known to be important in diverse developmental programs, but for the first time pinpoint cells throughout the skin that take part in these molecular conversations.
They also highlight the widespread activation of signals previously defined by their role in axon guidance signalling, which could have a role in directing the large scale cellular rearrangements important for functional skin development.
The team is sharing all data on the Hair Gene Expression Library website, Hair-GEL.net, which offers sequencing information on the stem cells and niche cells that interact to build hair follicles.
Researchers can query any gene of interest to see if it is present and/or specifically expressed in any one of the distinct cell types that compose embryonic skin.
Sennett R, Wang Z, Rezza A, Grisanti L, Roitershtein N, Sicchio C, Mok KW, Heitman NJ, Clavel C, Ma'ayan A, Rendl M (2015) An Integrated Transcriptome Atlas of Embryonic Hair Follicle Progenitors, their Niche and the Developing Skin. Developmental Cell doi:10.1016/j.devcel.2015.06.023