Navigation Links
Zebrafish research shows how dietary fat regulates cholesterol absorption

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
Genetics Society of America

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:
(Date:6/22/2016)... 22, 2016  The American College of Medical Genetics and ... Magazine as one of the fastest-growing trade shows during ... the Bellagio in Las Vegas . ... of growth in each of the following categories: net square ... number of attendees. The 2015 ACMG Annual Meeting was ranked ...
(Date:6/21/2016)... , June 21, 2016 NuData ... the new role of principal product architect and ... the director of customer development. Both will report ... technical officer. The moves reflect NuData,s strategic growth ... response to high customer demand and customer focus ...
(Date:6/15/2016)... York , June 15, 2016 ... new market report titled "Gesture Recognition Market by Application ... Forecast, 2016 - 2024". According to the report, the  ... 11.60 billion in 2015 and is estimated to ... USD 48.56 billion by 2024.  Increasing ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... Mass. , June 23, 2016   ... development of novel compounds designed to target cancer ... napabucasin, has been granted Orphan Drug Designation from ... the treatment of gastric cancer, including gastroesophageal junction ... stemness inhibitor designed to inhibit cancer stemness pathways ...
(Date:6/23/2016)... (PRWEB) , ... June 23, 2016 , ... ... Plate® YM (Yeast and Mold) microbial test has received AOAC Research Institute approval ... of microbial tests introduced last year,” stated Bob Salter, Vice President of Regulatory ...
(Date:6/23/2016)... ... June 23, 2016 , ... Supplyframe, the Industry Network ... Supplyframe Design Lab . Located in Pasadena, Calif., the Design Lab’s mission is ... projects are designed, built and brought to market. , The Design Lab is ...
(Date:6/23/2016)... June 23, 2016  Blueprint Bio, a company dedicated ... the medical community, has closed its Series A funding ... . "We have received a commitment from ... we need to meet our current goals," stated ... the runway to complete validation on the current projects ...
Breaking Biology Technology: