These cellular cornerstones direct embryonic patterning and wound healing by sending vital location cues to their neighbors, and may help in growing tissue for transplant or understanding metastatic cancer.
"There is a logic to the body that we didn't understand before," said John Rinn, PhD, a postdoctoral scholar in the laboratory of Howard Chang, MD, PhD, assistant professor of dermatology. "Our skin is actively maintaining itself throughout our life, and these 'address codes' help the cells know how to respond appropriately." Rinn is the first author of the research, which is published in the current issue of Public Library of Science-Genetics.
Until now it's been a mystery as to how adult skin, which consists of basically the same components all over the body, knows to grow hair in some areas like the scalp, while manufacturing sweat glands, calluses and fingerprint whorls in others. In 1969, well-known developmental biologist Lewis Wolpert authored a famous treatise that described two possible ways for cells to know where they are in the body: Either they infer their location and adjust their behavior based on interactions with nearby cells, or they deduce their "positional identity" through the use of some type of coordinate system. The findings from the new Stanford study bolster the second possibility.
The scientists analyzed the gene-expression profiles of adult fibroblasts from more than 40 areas of the body. They found about 400 genes whose expression patterns varied with the cells' original location. Those from the top half of the body - arms, head and chest, for example - shared expression patterns that were markedly different from the patterns shared among cells from the bottom part of the body, such as the legs and feet. Similar patterns existed among cells originating close to or far from the center of the body, and those from the outer or the inner layer of the skin.
While these three rough anatomical divisions don't provide the precise coordinates of a global-positioning system, they do help explain similarities between the skin on the palms of the hands and the relatively distant soles of the feet. Like botanically similar areas of the world that share a latitude and altitude but differ in longitude, both the palms and soles are on the outer layer of the skin far from the center of the body and are more like one another than like their biological neighbors.
"Ideally, we can use this finding to develop a positional map that will allow us to correlate location with function in a way that will make it easier to regenerate certain parts of the body," said Rinn. "For example, if we need to grow skin in the laboratory to graft onto someone with badly burned palms, we'll know how to turn on the specific genes that make that type of skin." The implications are vast. Fibroblasts and other skin cells also comprise the lining of the lung and intestine as well as internal organs.
Not every kind of skin cell expresses gene patterns that can be correlated with their location in the body; the study found no such association in endothelial cells, which might depend on signals from surrounding cells.
"It's not like every cell has this code," said Rinn. "I like to think of the fibroblasts as wise, old parental cells who may tell the others how to behave." Their input is invaluable during embryogenesis, normal growth and wound healing, each of which requires location-specific responses by cells. Many of the genes identified by Rinn are known to be important in patterning the early embryo.
Rinn and his colleagues speculate that some of these processes may require more specific location indicators than the three they've currently identified. It's possible that additional cues may be provided by variations in gene expression levels too subtle to be detected in their current study. Alternatively, cell types other than fibroblasts or endothelial cells may express signals that further refine the current rough map. Finally, it's possible that adults simply don't need the same level of precision mapping as a developing embryo, and they stop broadcasting the finer points of the signal when it's no longer necessary.
Krista Conger | EurekAlert!
A novel synthetic antibody enables conditional “protein knockdown” in vertebrates
20.08.2018 | Technische Universität Dresden
Climate Impact Research in Hannover: Small Plants against Large Waves
17.08.2018 | Leibniz Universität Hannover
There are currently great hopes for solid-state batteries. They contain no liquid parts that could leak or catch fire. For this reason, they do not require cooling and are considered to be much safer, more reliable, and longer lasting than traditional lithium-ion batteries. Jülich scientists have now introduced a new concept that allows currents up to ten times greater during charging and discharging than previously described in the literature. The improvement was achieved by a “clever” choice of materials with a focus on consistently good compatibility. All components were made from phosphate compounds, which are well matched both chemically and mechanically.
The low current is considered one of the biggest hurdles in the development of solid-state batteries. It is the reason why the batteries take a relatively long...
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
17.08.2018 | Event News
08.08.2018 | Event News
27.07.2018 | Event News
20.08.2018 | Information Technology
20.08.2018 | Life Sciences
20.08.2018 | Information Technology