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!
20.11.2017 | Washington University in St. Louis
Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.
Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...
Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
20.11.2017 | Earth Sciences
20.11.2017 | Earth Sciences
20.11.2017 | Life Sciences