Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Zebrafish Research Shows How Fat Regulates Cholesterol Absorption

26.06.2012
Buttery shrimp. Fried eggs. Burgers and fries. New research suggests there may be a biological reason why fatty and cholesterol-rich foods are so appealing together.

It has been known for more than 40 years that dietary fat promotes cholesterol uptake, but fundamental aspects of that process remain poorly understood. James Walters, Ph.D., and his colleagues at the Carnegie Institution for Science are using zebrafish to better understand the cellular mechanisms of cholesterol processing and have discovered a surprising link between dietary fat and cholesterol absorption.

“One reason these questions remain unknown is because of the difficulty of studying such a complex biological system as the intestine,” which in addition to multiple cell types also includes a diverse array of enzymes, mucus, and symbiotic bacteria, he said in a June 20 presentation at the ongoing 2012 International Zebrafish Development and Genetics Conference in Madison, Wisconsin.

As a postdoctoral fellow in Dr. Steven Farber’s lab at the Carnegie Institution for Science, in Baltimore, Maryland, Dr. Walters turned to young zebrafish, which provide a biologically complete and scientifically accessible system for studying the workings of the gut.

“Because the larval zebrafish are optically clear, we can visualize fat transport and processing by looking right through their body wall into the intestine where the action is,” Dr. Walters said.

He developed a way to feed zebrafish a diet high in lipids (e.g., fat and cholesterol) or high in protein and low in lipids. He accomplished this by turning to the chicken egg, whipping fish water with the yolk for a high-lipid diet and the egg white as a high-protein diet. Before feeding these diets, fluorescently tagged cholesterol or fatty acid was added, enabling the microscopic viewing of how lipids are absorbed and processed by the intestinal cells.

Dr. Walters found that cholesterol was only absorbed when the fish ate a high-fat diet, not a low-fat diet. The fats and cholesterol were packaged into separate and clearly visible compartments within the cells. “You can tell which larvae had eggs for breakfast,” he said.

The researchers also found that some long-chain fatty acids, particularly a common one called oleic acid, were especially effective for promoting cholesterol uptake. They provided evidence that oleic acid acts to drive a cholesterol transport protein from within the intestinal cell to the cell surface, where it can interact with cholesterol passing through the gut and pull it into the cell. More details of the new work will be published next week.

Their findings suggest a tightly regulated system in which cholesterol is only taken up by the intestine in the presence of fats. One reason such regulation is important, Dr. Walters said, is that unprocessed cholesterol can be toxic to cells and requires fatty acid-mediated modification to render it safe in a process called esterification.

“In nature, cholesterol and fatty acids go hand in hand. It makes sense that you could use dietary fatty acids as a cue for the transport protein to translocate to the cell surface and that dietary cholesterol may be available for absorption,” he said. “The protein isn’t displayed on the cell surface unless its preferred substrate for making cholesterol less toxic is also there.”

Dr. Walters and his colleagues are now exploring the system’s potential for studying and testing compounds that can block the absorption of dietary cholesterol, including one drug already on the market.

“Diet is a huge modulator of human disease,” says Dr. Walters. “Our work demonstrates the power of the zebrafish larval system to provide fresh insights into the process of intestinal cholesterol absorption. It gives us a way to look at these processes for the first time in the context of a whole organism.”

ABOUT THE INTERNATIONAL CONFERENCE ON ZEBRAFISH GENETICS AND DEVELOPMENT: The zebrafish emerged as a major model system in 1994 with the first international conference at Cold Spring Harbor with 350 participants. This year, the zebrafish community celebrates its 10th biennial international conference with more than 900 participants in Madison, WI. Studies using the zebrafish as a model system have allowed us to understand the genetic control of early development that underlies many human diseases. For more information about the conference, see www.zebrafishgenetics.org.

ABOUT GSA: Founded in 1931, the Genetics Society of America (GSA) is the professional membership organization for scientific researchers, educators, bioengineers, bioinformaticians and others interested in the field of genetics. Its nearly 5,000 members work to advance knowledge in the basic mechanisms of inheritance, from the molecular to the population level.

GSA is dedicated to promoting research in genetics and to facilitating communication among geneticists worldwide through its conferences, including the biennial conference on Model Organisms to Human Biology, an interdisciplinary meeting on current and cutting edge topics in genetics research, as well as annual and biennial meetings that focus on the genetics of particular organisms, including C. elegans, Drosophila, fungi, mice, yeast, and zebrafish. GSA publishes GENETICS, a leading journal in the field and an online, open-access journal, G3: Genes|Genomes|Genetics. For more information about GSA, please visit www.genetics-gsa.org. Also follow GSA on Facebook at facebook.com/GeneticsGSA and on Twitter @GeneticsGSA.

Phyllis Edelman | Newswise Science News
Further information:
http://www.genetics-gsa.org

More articles from Health and Medicine:

nachricht Vanishing capillaries
23.03.2017 | Technische Universität München

nachricht How prenatal maternal infections may affect genetic factors in Autism spectrum disorder
22.03.2017 | University of California - San Diego

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

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

Im Focus: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

When Air is in Short Supply - Shedding light on plant stress reactions when oxygen runs short

23.03.2017 | Life Sciences

Researchers use light to remotely control curvature of plastics

23.03.2017 | Power and Electrical Engineering

Sea ice extent sinks to record lows at both poles

23.03.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>