Distinct stem cell types contribute to mammary gland development.
A Belgian research team has identified novel classes of breast stem cells that ensure the development and expansion of the different cell lineages of the mammary gland during pregnancy.
One of the key questions in biology is the identification of stem cells responsible for tissue morphogenesis and regeneration.
The mammary gland expands considerably during puberty and pregnancy, during which it differentiates into milk-producing cells.
Two different cell types formed the mammary gland: the myoepithelial cells and luminal cells, which can differentiate either into ductal cells or milk-producing cells.
Whereas ductal and milk-producing cells secrete the water and nutriments essential for the survival of young mammalian offspring, the myoepithelial cells, through their contraction, guide the circulation of the milk throughout the ductal tree toward the nipple.
To precisely define the cellular hierarchy of mammary gland during physiological conditions, A. Van Keymeulen and colleagues used a novel state of the art genetic lineage tracing approach to fluorescently mark the different cell types of the mammary gland and follow the fate of fluorescent marked cells overtime. The researchers found that both luminal and myoepithelial lineages contain long lived unipotent stem cells which present extensive renewing capacities, as demonstrated by their ability to expand during morphogenesis and undergo massive expansion during several cycles of pregnancy.
"We were all very surprised and excited when we discovered that the mammary glands are maintained by two classes of unipotent stem ensuring the renewal and differentiation of their respective lineages rather than by multipotent stem cells. These findings radically change our understanding of the regenerative potential of the mammary gland during physiological condition" said Alexandra Van Keymeulen, Ph.D., co-first author of this study.
"These new findings will be extremely important for those studying development, stem cells and mammary gland but will also open new avenues to uncover the cells at the origin of the different subtypes of breast cancers, a very important and unanswered question" said Cedric Blanpain, M.D., Ph.D., of the Universite libre de Bruxelles (Belgium), the senior and corresponding author.
In conclusion, this new study identifies new stem cell populations in the breast tissue that ensure the development and the maintenance of the mammary gland throughout life.
Citation: "Distinct stem cells contribute to mammary gland development and maintenance;" Alexandra Van Keymeulen, Ana Sofia Rocha, Marielle Ousset, Benjamin Beck, Gaelle Bouvencourt, Cedric Blanpain, et al.; Nature, 2011;DOI: 10.1038/naturel0573
Contact: Cedric Blanpain, firstname.lastname@example.org
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|Title Annotation:||Basic Research|
|Publication:||Stem Cell Research News|
|Date:||Oct 17, 2011|
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