Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Intestinal stem cells respond to food by supersizing the gut

28.10.2011
Locally released insulin activates stem cells to produce more gut and stem cells

A new study from University of California, Berkeley, researchers demonstrates that adult stem cells can reshape our organs in response to changes in the body and the environment, a finding that could have implications for diabetes and obesity.

Current thinking has been that, once embryonic stem cells mature into adult stem cells, they sit quietly in our tissues, replacing cells that die or are injured but doing little else.

But in working with fruit flies, the researchers found that intestinal stem cells responded to increased food intake by producing more intestinal cells, expanding the size of the intestines as long as the food keeps flowing.

"When flies start to eat, the intestinal stem cells go into overdrive, and the gut expands," said UC Berkeley post-doctoral fellow Lucy O'Brien. "Four days later, the gut is four times bigger than before, but when food is taken away, the gut slims down."

Just as in humans and other mammals, O'Brien added, the fly intestine secretes its own insulin. In flies, intestinal insulin seems to be the signal that makes stem cells "supersize the gut."

"Because of the many similarities between the fruit fly and the human, the discovery may hold a key to understanding how human organs adapt to environmental change," said David Bilder, UC-Berkeley associate professor of molecular and cell biology.

The research will be published in the Oct. 28 issue of the journal Cell.

Stem cells key to adaptability

Many tissues grow or shrink with usage, including muscle, liver and intestine. Human intestines, for example, regrow after portions have been surgically removed because of cancer or injury, and hibernating animals see their intestines shrink to one-third their normal size during winter.

"One strategy animals use to deal with environmental variability is to tune the workings of their organ systems to match the conditions at hand," O'Brien said. "How exactly this 'organ adaptation' happens, particularly in adult animals that are no longer growing, has long been a mystery."

Following the surprising discovery of stem cells in the intestines of fruit flies five years ago, O'Brien and Bilder decided to investigate the role of adult stem cells in normal intestinal growth in hopes of finding clues to their role in vertebrates like us.

"I looked at stained stem cells in the fruit fly intestine, and they are studded throughout like jewels. The tissues were so beautiful, I knew I had to study them," O'Brien said.

O'Brien, Bilder and their colleagues discovered that when fruit flies feed, their intestines secrete insulin locally, which stimulates intestinal stem cells to divide and produce more intestinal cells.

"The real surprise was that the fruit fly intestine is capable of secreting its own insulin," BIlder said. "This intestinal insulin spikes immediately after feeding and talks directly to stem cells, so the intestine controls its own adaptation."

Stem cells can divide either asymmetrically, producing one stem cell and one intestinal cell, or symmetrically, producing two stem cells. The team found that, in response to food, intestinal stem cells underwent symmetric division more frequently than asymmetric division, which had the effect of maintaining the proportion of stem cells to intestinal cells, and is a more efficient way of ramping up the total number of cells, O'Brien said.

"Adaptive resizing of the intestine makes sense from the standpoint of physiological fitness," she said. "Upkeep of the intestinal lining is metabolically expensive, consuming up to 30 percent of the body's energy resources. By minimizing intestinal size when food is scarce, and maximizing digestive capacity when food is abundant, adaptive intestinal resizing by stem cells helps animals survive in constantly changing environments."

Bilder and O'Brien's coauthors on the Cell paper are UC Berkeley staff researchers Sarah S. Soliman and Xinghua Li.

The work was supported by the National Institutes of Health and, for O'Brien, by a Genentech Foundation Fellowship of the Life Sciences Research Foundation.

Robert Sanders | EurekAlert!
Further information:
http://www.berkeley.edu

More articles from Life Sciences:

nachricht Symbiotic bacteria: from hitchhiker to beetle bodyguard
28.04.2017 | Johannes Gutenberg-Universität Mainz

nachricht Nose2Brain – Better Therapy for Multiple Sclerosis
28.04.2017 | Fraunhofer-Institut für Grenzflächen- und Bioverfahrenstechnik IGB

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Fighting drug resistant tuberculosis – InfectoGnostics meets MYCO-NET² partners in Peru

28.04.2017 | Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

 
Latest News

Wireless power can drive tiny electronic devices in the GI tract

28.04.2017 | Medical Engineering

Ice cave in Transylvania yields window into region's past

28.04.2017 | Earth Sciences

Nose2Brain – Better Therapy for Multiple Sclerosis

28.04.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>