'Glue' holding together skin cells, other epithelial tissue more active than realized

The strong mechanical attachments -- the "glue" -- that hold together the cells of the skin and the other epithelial tissues of the body are the adherens junctions.

These junctions are responsible for maintaining the shape and integrity of the sheets of epithelial cells that line such body cavities as the digestive tract, as well as the surfaces of structures such as the heart. Defects in the proteins of these attachments have been implicated as potential contributors to the development and spread of cancer.

Recent research on Drosophila flies, combined with previous studies in cell cultures, are challenging the traditional view that adherens junctions maintain tissue integrity by passively resisting disruptive forces.

In studies with Drosophila embryos, the Princeton University lab of Nobel laureate Eric Wieschaus, Ph.D., has uncovered the first evidence in living organisms that adherens junctions actively respond to mechanical cues by remodeling their own position and intensity, which in turn restructures the cells.

Mo Weng, Ph.D., postdoctoral fellow in the lab, used live imaging and quantitative image analysis of fixed and live embryos to determine that these changes depend on mechanical force mediated by the motor protein myosin and precede the changes in the distribution of cell polarity proteins, such as Bazooka, that are responsible for spatial organization of the cells.

Understanding the regulation and functioning of adherens junctions sheds light on the organization of multi-cellularity -- from cell-cell contacts to the remodeling of tissues and organs during life.

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The above story is based on materials provided by Genetics Society of America. Note: Materials may be edited for content and length.

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Survey identifies the incurable, a rare type of soft tissue cancers of a potential therapeutic target.

Research published in the online mobile report, UT Southwestern Medical Center （ Harold, C, Simmons Cancer Center home ） from scientists discovered that inhibits the action of a protein known as BRD4 cancer cells in a mouse model of malignant peripheral nerve sheath tumors (MPNSTs) caused the death. MPNSTs are formed around an aggressive Sarcoma nervous. About half of the cases in patients with a genetic disorder called these tumors can develop sporadically, but with 1 to 3,500 people affect nerve fiber of the types （ NF1 ） 1.

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Plants in space: A novel method for fixing plant tissue samples maximizes time, resources, and data

Sep. 11, 2013 — At work on the International Space Station, researchers studying plant and cell growth in space encountered a challenge. Imaging revealed interesting spaceflight-associated root morphologies. They needed to fix the tissues for further study back on Earth, but conventional fixation methods require separate fixatives depending on whether the sample is intended for molecular or morphological study. If the scientists wanted to study how spaceflight affected patterns of gene expression central to morphological patterns of cell growth, they needed a fixation method that would allow them to study both perspectives.

Most scientists at work in the laboratory rely on protocols that have been developed without the need for restrictions on the amount of space, time, or reagents they use. For scientists conducting experiments in spaceflight, time and resources are strictly regulated and limited, and researchers must know in advance which protocols will maximize the usefulness of the data they collect.

University of Florida professors Anna-Lisa Paul and Robert Ferl and colleagues are collaborating with the National Aeronautics and Space Administration (NASA) to understand plant growth and development in spaceflight. Along with lead author and graduate student Eric Schultz, they have developed a single fixation protocol for use in space that allows plant material to be used for multiple experimental applications. Their new protocol for sample preparation was tested on Arabidopsis tissues harvested on the International Space Station and is described in the August issue of Applications in Plant Sciences.

Because of limitations in astronaut crew time and orbital resources, previous spaceflight fixation protocols were designated as either molecular or morphological, due to the separate fixatives required for each application. Tissues for morphologic study were fixed in 3% glutaraldehyde (or a similar solution), and tissues for molecular study were fixed in the tissue storage reagent RNAlater. RNAlater has not commonly been used as a morphologic fixative, as it can produce unclear images with high background staining.

The new method developed by Schultz et al. puts RNAlater-fixed samples through a desalination process to return them to a fresh-like state, and then uses low-temperature scanning electron microscopy (cryo-SEM) to preserve tissues for imaging. Because few laboratories have access to the necessary equipment for cryo-SEM, the authors tested and developed a protocol that emulates cryo-SEM using standard SEM equipment and, importantly, that results in minimal tissue damage.

Although it was developed to address specific constraints for spaceflight experiments, Paul notes that their new method is broadly applicable. "There are a lot of situations where biologists want to collect samples in extreme situations. In our case -- a space vehicle orbiting the Earth."

The new protocol maximizes the amount of data obtained from a single sample and allows for the concomitant examination of both molecular and morphological features. Using a single fixation protocol, direct comparisons between changes in morphology and altered gene expression can be made. Such an analysis not only makes full use of samples and replicates but also enables a robust analysis of the relationship between heredity and development. "Putting two tools together, it is powerful to look at the morphology in conjunction with the genes that are being expressed," says Paul.

The new protocol boasts low costs and high accessibility, and has wide application to any situation where recovery of biological resources is limited. Notably, this includes researchers collecting and preserving samples in the field, where space for materials is at a premium. "In places where sampling is limited, difficult, or expensive, the use of preservatives allows for more routes to analysis," notes Ferl.

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Adult tissue 'sent back to embryo'

11 September 2013 Last updated at 17:05 GMT By James Gallagher Health and science reporter, BBC News Stem cells can become any tissue type in the body The living tissue inside an animal has been regressed back into an embryonic state for the first time, Spanish researchers say.

They believe it could lead to new ways of repairing the body, for example after a heart attack.

However, the study published in the journal Nature, showed the technique led to tumours forming in mice.

Stem cell experts said it was a "cool" study, but would need to be much more controlled before leading to therapies.

When an egg is first fertilised, it has the potential to develop into every tissue in the human body, from brain cells to skin.

That flexibility is lost as an embryo develops. However, transforming adult tissues back into an embryonic-like state may lead to treatments that can regenerate a weakened heart, or the light-sensing cells in the eye or even the brain after a stroke.

'Thought impossible'

The transformation has been done in a laboratory, by treating skin samples with a mix of chemicals or genetic modification.

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It will be a monumental task to prove this is safe as what you're doing is innately dangerous, but it is exciting as it's potentially a new strategy for regenerative medicine.”

End Quote Prof Robin Ali Institute of Ophthalmology Now scientists at the Spanish National Cancer Research Centre in Madrid have achieved the same results inside an animal.

"It is a surprising result, this was not expected, most of us thought that it would be impossible," lead researcher Prof Manuel Serrano told the BBC.

The research group used mice genetically modified to switch on, when they were given a specific drug, production of four chemicals shown to reverse a tissue's destiny in the laboratory.

Tissues were successfully transformed back into an embryonic state, but without further direction they rapidly developed into tumours.

Speaking on Science In Action on the BBC World Service, Prof Serrano said: "Of course this is not what we want for regenerative medicine.

"We want to turn back the clock in a controlled manner and this is something we have to work out in the future.

"We have to find conditions where we reprogramme only partially so that they acquire a plastic state and repair the tissue."

'Monumental task'

Prof Robin Ali, from the Institute of Ophthalmology in London, is using stem cell technology to rebuild the retina to restore sight. He said the "ultimate goal" would be some treatment that could regenerate the back of the eye, "but that is a long way off".

He added: "This is a really elegant study with important implications for the field.

"It will be a monumental task to prove this is safe, as what you're doing is innately dangerous, but it is exciting as it's potentially a new strategy for regenerative medicine."

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Overall it's very cool and potentially very exciting, but it has massive issues in terms of control”

End Quote Prof Chris Mason University College London The technique was able to turn the clock back further than any other stem cell technology, including stem cells taken from an embryo.

Previous techniques produce stem cells that make the tissues found in the body. This study could also make those needed to support an embryo in the womb, such as the placenta.

Prof Robin Lovell-Badge, from the MRC's National Institute of Medical Research, told the BBC that he could not see this technique leading directly to therapies, but rather improving scientific understanding.

"To me the interesting thing was the evidence that the cells correspond to an earlier stage of development.

"If we can repeat that with human cells, it would be incredibly useful and could have important research implications, such as understanding the placenta and how to help maintain a pregnancy."

Prof Chris Mason, a stem cell scientist at University College London, said: "Overall it's very cool and potentially very exciting, but it has massive issues in terms of control."

Instead he thought techniques that transformed cells in the body directly into the desired tissue would be better than going via stem cells.

"It's like a tree, instead of going down from a branch to the root and back up to a different branch, maybe we'll be able to jump from branch to branch."

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