Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UCLA identifies new molecule involved in the body's processing of dietary fat

04.04.2007
UCLA investigators have identified a new molecule that may help regulate the delivery of fats to cells for energy and storage.

Published in the April issue of the journal Cell Metabolism, the finding could lead to a better understanding of how we utilize fats from the foods we eat.

"We thought that we had figured out how the body digests and uses fats, but we have identified a completely new player in the game," said the study's author Anne Beigneux, assistant investigator at the David Geffen School of Medicine at UCLA.

Digested fats travel to the small intestine, where they are packaged into chylomicrons, which are large, spherical particles filled with triglycerides.

Chylomicrons then travel through the bloodstream and deliver triglycerides to the skeletal muscles and heart — tissues that are hungry for fuel — or to adipose tissue for energy storage. Molecules called proteoglycans, attached to the inside walls of capillaries, wait like baseball players with their mitts open, poised to catch the passing chylomicrons.

Proteoglycans hold the chylomicrons steady while the triglycerides are broken down or hydrolyzed by the enzyme lipoprotein lipase (LpL). The triglyceride breakdown products are then taken up and used by cells.

"Previously we didn't know what molecule in the capillaries facilitated the capture of chylomicrons and facilitated the interaction with lipoprotein lipase," said Dr. Stephen Young, study author and investigator at the David Geffen School of Medicine at UCLA. "We think that we've found the missing piece of the puzzle."

Investigators discovered that a protein called glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1) may be the missing link.

Scientists found that mice deficient in GPIHBP1 develop very high triglyceride levels, even on a normal diet, demonstrating that fats in the bloodstream are not readily metabolized in the absence of GPIHBP1.

Laboratory tests confirmed that GPIHBP1-deficient mice had much higher levels of chylomicrons in the bloodstream than normal mice. The GPIHBP1-deficient mice had grossly milky plasma, reflecting very large amounts of triglycerides in the blood.

"These findings indicate a defect in the breakdown of chylomicrons in mice that don't have GPIHBP1," Beigneux said.

Investigators predicted that if GPIHBP1 were involved in the processing of chylomicrons in the bloodstream, then the protein would be made by endothelial cells of capillaries, where the breakdown of triglycerides takes place. Indeed, microscopy showed that GPIHBP1 is expressed highly and exclusively on the endothelial cells of capillaries of heart, adipose tissue and skeletal muscle.

Interestingly, scientists found that this protein was absent from the brain, which mainly uses glucose for energy.

"These differences suggest that endothelial cells may play an active role in regulating the delivery of lipid nutrients to different tissues," Beigneux said.

Experiments with cultured cells revealed that GPIHBP1 binds both chylomicrons and lipoprotein lipase, suggesting GPIHBP1 is a key platform for the processing of chylomicrons.

The next step, according to investigators, will be to determine if GPIHBP1 provides the only binding site for chylomicrons and lipoprotein lipase within capillaries. In addition, investigators would like to define the molecular basis for how GPIHBP1 binds to chylomicron particles.

Rachel Champeau | EurekAlert!
Further information:
http://www.mednet.ucla.edu

Further reports about: GPIHBP1 Lipase Triglyceride UCLA capillaries chylomicron endothelial cell lipoprotein

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>