Navigation Links
Zebrafish research shows how dietary fat regulates cholesterol absorption
Date:6/22/2012

MADISON, WI June 22, 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."


'/>"/>

Contact: Phyllis Edelman
pedelman@genetics-gsa.org
301-351-0896
Genetics Society of America
Source:Eurekalert

Related biology news :

1. Versatility of zebrafish research highlighted at international conference
2. Environmental estrogens affect early developmental activity in zebrafish
3. Zebrafish could hold the key to understanding psychiatric disorders
4. Better housing conditions for zebrafish could improve research results
5. Notre Dame establishes professorships in adult stem cell research
6. Research: Many programs to help diabetics manage their health do work
7. Autism Speaks awards nearly $2.9 million to fund autism research
8. Researchers advance biometric security
9. University of Tennessee professor receives funding for clean coal research
10. Research could help track stem cells in the body
11. Argonne researchers receive 4 R&D 100 awards
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/26/2016)... LONDON , April 26, 2016 /PRNewswire/ ... Systems, a product subsidiary of Infosys (NYSE: ... partnership to integrate the Onegini mobile security platform ... http://photos.prnewswire.com/prnh/20151104/283829LOGO ) The integration ... security to access and transact across channels. Using ...
(Date:4/15/2016)... April 15, 2016  A new partnership announced ... accurate underwriting decisions in a fraction of the ... priced and high-value life insurance policies to consumers ... With Force Diagnostics, rapid testing (A1C, Cotinine ... readings (blood pressure, weight, pulse, BMI, and activity ...
(Date:4/13/2016)...  IMPOWER physicians supporting Medicaid patients in ... standard in telehealth thanks to a new partnership with ... IMPOWER patients can routinely track key health measurements, such ... and, when they opt in, share them with IMPOWER ... local retail location at no cost. By leveraging this ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... DIEGO , June 24, 2016 ... more sensitively detects cancers susceptible to PARP inhibitors ... circulating tumor cells (CTCs). The new test has ... HRD-targeted therapeutics in multiple cancer types. ... targeting DNA damage response pathways, including PARP, ATM, ...
(Date:6/23/2016)... ... June 23, 2016 , ... ... announce the launch of their brand, UP4™ Probiotics, into Target stores nationwide. The ... is proud to add Target to its list of well-respected retailers. This list ...
(Date:6/23/2016)... , June 23, 2016 Houston Methodist ... the Cy-Fair Sports Association to serve as their ... agreement, Houston Methodist Willowbrook will provide sponsorship support, ... connectivity with association coaches, volunteers, athletes and families. ... the Cy-Fair Sports Association and to bring Houston ...
(Date:6/23/2016)... FRANCISCO , June 23, 2016   EpiBiome ... has secured $1 million in debt financing from Silicon ... ramp up automation and to advance its drug development ... its new facility. "SVB has been an ... beyond the services a traditional bank would provide," said ...
Breaking Biology Technology: