Scientists at the Monell Center have identified the location and certain genetic characteristics of taste stem cells on the tongue. The findings will facilitate techniques to grow and manipulate new functional taste cells for both clinical and research purposes.
"Cancer patients who have taste loss following radiation to the head and neck and elderly individuals with diminished taste function are just two populations who could benefit from the ability to activate adult taste stem cells," said Robert Margolskee, M.D., Ph.D., a molecular neurobiologist at Monell who is one of the study's authors.
Taste cells are located in clusters called taste buds, which in turn are found in papillae, the raised bumps visible on the tongue's surface.
Two types of taste cells contain chemical receptors that initiate perception of sweet, bitter, umami, salty, and sour taste qualities. A third type appears to serve as a supporting cell.
A remarkable characteristic of these sensory cells is that they regularly regenerate. All three taste cell types undergo frequent turnover, with an average lifespan of 10-16 days. As such, new taste cells must constantly be regenerated to replace cells that have died.
For decades, taste scientists have attempted to identify the stem or progenitor cells that spawn the different taste receptor cells. The elusive challenge also sought to establish whether one or several progenitors are involved and where they are located, whether in or near the taste bud.
Drawing on the strong physiological relationship between oral taste cells and endocrine (hormone producing) cells in the intestine, the Monell team used a marker for intestinal stem cells to probe for stem cells in taste tissue on the tongue.
Stains for the stem cell marker, known as Lgr5 (leucine-rich repeat-containing G-protein-coupled receptor 5), showed two patterns of expression in taste tissue. The first was a strong signal underlying taste papillae at the back of the tongue and the second was a weaker signal immediately underneath taste buds in those papillae.
The Monell scientists hypothesize that the two levels of expression could indicate two different populations of cells. The cells that more strongly express Lgr5 could be true taste stem cells, whereas those with weaker expression could represent those stem cells that have begun the transformation into functional taste cells.
Additional studies revealed that the Lgr5-expressing cells were capable of becoming any one of the three major taste cell types.
The findings are published online in the journal Stem Cells.
"This is just the tip of the iceberg," said senior author Peihua Jiang, Ph.D., also a Monell molecular neurobiologist. "Identification of these cells opens up a whole new area for studying taste cell renewal, and contributes to stem cell biology in general."
Future studies will focus on identifying the factors that program the Lgr5-expressing cells to differentiate into the different taste cell types, and explore how to grow these cells in culture, thus providing a renewable source of taste receptor cells for research and perhaps even clinical use.
Other authors from Monell that contributed to the work are Karen Yee, Yan Li and Kevin Redding.
Research reported in this publication was supported by the National Institute on Deafness and Other Communication Disorders under award numbers DC0101842, DC003055, and 1P30DC011735, and National Institute of Diabetes and Digestive and Kidney Diseases grant DK081421. Both institutes are part of the National Institutes of Health. Additional funding was provided by the Commonwealth of Pennsylvania Department of Health.
The Monell Chemical Senses Center is an independent nonprofit basic research institute based in Philadelphia, Pennsylvania. For 45 years, Monell has advanced scientific understanding of the mechanisms and functions of taste and smell to benefit human health and well-being. Using an interdisciplinary approach, scientists collaborate in the programmatic areas of sensation and perception; neuroscience and molecular biology; environmental and occupational health; nutrition and appetite; health and well-being; development, aging and regeneration; and chemical ecology and communication. For more information about Monell, visit www.monell.org.
Leslie Stein | Source: EurekAlert!
Further information: www.monell.org
More articles from Life Sciences:
Tokyo Institute of Technology research: An insight into cell survival
17.05.2013 | Tokyo Institute of Technology
Asian lady beetles use biological weapons against their European relatives
17.05.2013 | Max-Planck-Institut für chemische Ökologie
Researchers have shown that, by using global positioning systems (GPS) to measure ground deformation caused by a large underwater earthquake, they can provide accurate warning of the resulting tsunami in just a few minutes after the earthquake onset.
For the devastating Japan 2011 event, the team reveals that the analysis of the GPS data and issue of a detailed tsunami alert would have taken no more than three minutes. The results are published on 17 May in Natural Hazards and Earth System Sciences, an open access journal of ...
A new study of glaciers worldwide using observations from two NASA satellites has helped resolve differences in estimates of how fast glaciers are disappearing and contributing to sea level rise.
The new research found glaciers outside of the Greenland and Antarctic ice sheets, repositories of 1 percent of all land ice, lost an average of 571 trillion pounds (259 trillion kilograms) of mass every year during the six-year study period, making the oceans rise 0.03 inches (0.7 mm) per year. ...
About 99% of the world’s land ice is stored in the huge ice sheets of Antarctica and Greenland, while only 1% is contained in glaciers.
However, the meltwater of glaciers contributed almost as much to the rise in sea level in the period 2003 to 2009 as the two ice sheets: about one third. This is one of the results of an international study with the involvement of geographers from the University of Zurich.
Second sound is a quantum mechanical phenomenon, which has been observed only in superfluid helium.
Physicists from the University of Innsbruck, Austria, in collaboration with colleagues from the University of Trento, Italy, have now proven the propagation of such a temperature wave in a quantum gas. The scientists have published their historic findings in the journal Nature.
Below a critical temperature, certain fluids become superfluid ...
Researchers use synthetic silicate to stimulate stem cells into bone cells
In new research published online May 13, 2013 in Advanced Materials, researchers from Brigham and Women's Hospital (BWH) are the first to report that synthetic silicate nanoplatelets (also known as layered clay) can induce stem cells to become bone cells without the need of additional bone-inducing factors.
Synthetic silicates are made ...
17.05.2013 | Physics and Astronomy
17.05.2013 | Physics and Astronomy
17.05.2013 | Physics and Astronomy
17.05.2013 | Event News
15.05.2013 | Event News
08.05.2013 | Event News