Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Learning About High Cholesterol, Obesity From Fruit Flies

04.12.2009
How do fruit flies get high cholesterol and become obese? The same way as people do – by eating a diet that’s too rich in fats.

More importantly, according to two new studies led by a University of Utah human geneticist, fruit flies use the same molecular mechanisms as humans to help maintain proper balances of cholesterol and a key form of stored fat that contributes to obesity. The findings mean that as researchers try to learn more about the genetic and biological processes through which people regulate cholesterol and fat metabolism, the humble fruit fly, also called Drosophila, can teach humans much about themselves.

“Not a lot is known about these regulatory mechanisms in people,” says Carl S. Thummel, Ph.D., professor of human genetics at the U of U School of Medicine and senior author on the two studies. “But we can learn a lot by studying metabolic control in fruit flies and apply what we learn to humans.”

High cholesterol and obesity, which affects an estimated 25 percent to 30 percent of the U.S. population, are linked to heart disease, diabetes, and other diseases that take huge tolls on health and add billions of dollars to the nation’s medical bills. Understanding the processes that regulate cholesterol and fat in humans could be critical for addressing those health risks in people, Thummel believes.

The two studies identify a nuclear receptor, DHR96, which plays a critical role in regulating the balance or homeostasis of cholesterol and another fat molecule called triacylglycerol (TAG). Nuclear receptors are proteins that sense the presence of chemical compounds within cells. DHR96 corresponds closely to a nuclear receptor in humans, called LXR, that is known to regulate cholesterol levels.

In a study published Dec. 2 in Genes and Development, Thummel and colleagues at the U of U and two Canadian universities show that DHR96 helps regulate cholesterol in fruit flies by binding with this compound. When this binding occurs, it allows DNA to be read, which switches genes on and off that help maintain proper levels of cholesterol, according to Thummel, who also holds an H.A. and Edna Benning Presidential Endowed Chair in Human Genetics.

The researchers used a technique developed by University of Utah biologist Kent Golic, Ph.D., in which they silenced or disabled the DHR96 protein so it couldn’t function in fruit flies. They then grew flies in which DHR96 was silenced. Depending on what the fruit flies were fed, lean or fat diets, they had either too little or too much cholesterol. Flies fed too little cholesterol died, while those with too much developed hypercholesterolemia or chronically excessive cholesterol levels. At the same time, flies in which DHR96 functioned normally maintained a proper level of cholesterol.

“When they lacked the DHR96 receptor, the flies were unable to maintain cholesterol homeostasis,” Thummel says. “This is similar to what happens in humans who have high cholesterol levels.”

Fruit flies are good for such research insights in large part because of the insects’ short life span – about 30 days – meaning their development and biological processes are more easily observed than in other, longer-lived models, such as mice. Fruit flies also are easy to manipulate genetically and are less expensive to study compared to mice or other models, according to Thummel. In addition, the mechanisms by which metabolism is controlled in fruit flies are very similar to those in mice or humans.

“We can do a lot more mechanistic studies in a fly than are possible in a mouse,” he says. “We can study metabolic pathways faster and more in-depth.”

Along with its important role in helping to maintain proper levels of cholesterol, DHR96 also plays an integral part in regulating dietary fat metabolism, Thummel and another U of U researcher report in a Dec. 2 study in Cell Metabolism.

In flies in which DHR96 was silenced, TAG levels were markedly reduced in the intestine, making the insects resistant to diet-induced obesity. But when DHR96 was overexpressed, meaning there were higher levels of the protein, it led to increased TAG levels and made the flies more prone to being overweight. These findings show that DHR96 is required for breaking down dietary fat in the intestine of fruit flies and provide insight into how dietary fat metabolism is regulated in Drosophila.

“This nuclear receptor plays a major role in sensing and regulating cholesterol and TAG uptake in the intestine in fruit flies,” Thummel says. “It functions similarly to the way LXR functions in humans, although we have a relatively poor understanding about how LXR controls these pathways.”

In his future studies, Thummel intends to learn more about how DHR96 regulates metabolism by studying the functions of the genes that it controls.

Phil Sahm | Newswise Science News
Further information:
http://www.utah.edu

More articles from Life Sciences:

nachricht The irresistible fragrance of dying vinegar flies
16.08.2017 | Max-Planck-Institut für chemische Ökologie

nachricht How protein islands form
15.08.2017 | Albert-Ludwigs-Universität Freiburg im Breisgau

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

Im Focus: Scientists improve forecast of increasing hazard on Ecuadorian volcano

Researchers from the University of Miami (UM) Rosenstiel School of Marine and Atmospheric Science, the Italian Space Agency (ASI), and the Instituto Geofisico--Escuela Politecnica Nacional (IGEPN) of Ecuador, showed an increasing volcanic danger on Cotopaxi in Ecuador using a powerful technique known as Interferometric Synthetic Aperture Radar (InSAR).

The Andes region in which Cotopaxi volcano is located is known to contain some of the world's most serious volcanic hazard. A mid- to large-size eruption has...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

New thruster design increases efficiency for future spaceflight

16.08.2017 | Physics and Astronomy

Transporting spin: A graphene and boron nitride heterostructure creates large spin signals

16.08.2017 | Materials Sciences

A new method for the 3-D printing of living tissues

16.08.2017 | Interdisciplinary Research

VideoLinks
B2B-VideoLinks
More VideoLinks >>>