Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Findings show insulin - not genes - linked to obesity

16.04.2009
Researchers have uncovered new evidence suggesting factors other than genes could cause obesity, finding that genetically identical cells store widely differing amounts of fat depending on subtle variations in how cells process insulin.

Learning the precise mechanism responsible for fat storage in cells could lead to methods for controlling obesity.

"Insights from our study also will be important for understanding the precise roles of insulin in obesity or Type II diabetes, and to the design of effective intervention strategies," said Ji-Xin Cheng, an assistant professor in Purdue University's Weldon School of Biomedical Engineering and Department of Chemistry.

Findings indicate that the faster a cell processes insulin, the more fat it stores.

Other researchers have suggested that certain "fat genes" might be associated with excessive fat storage in cells. However, the Purdue researchers confirmed that these fat genes were expressed, or activated, in all of the cells, yet those cells varied drastically - from nearly zero in some cases to pervasive in others - in how much fat they stored.

The researchers examined a biological process called adipogenesis, using cultures of a cell line called 3T3-L1, which is often used to study fat cells. In adipogenesis, these cells turn into fat.

"This work supports an emerging viewpoint that not all biological information in cells is encoded in the genetic blueprint," said Thuc T. Le, a National Institutes of Health postdoctoral fellow at Purdue who is working with Cheng. "We found that the variability in fat storage is dependent on how 3T3-L1 cells process insulin, a hormone secreted by the pancreas after meals to trigger the uptake of glucose from the blood into the liver, muscle or fat cells."

The findings are detailed in a research paper appearing online in the journal PLoS ONE, published by the Public Library of Science, a non-profit organization of scientists and physicians.

"This varied capability to store fat among genetically identical cells is a well-observed but poorly understood phenomenon," Cheng said

The researchers determined that these differences in fat storage depend not on fat-gene expression but on variations in a cascade of events within an "insulin-signaling pathway." The pathway enables cells to take up glucose from the blood.

"Only one small variation at the beginning of the cascade can lead to a drastic variation in fat storage at the end of the cascade," Cheng said.

The researchers conducted "single cell profiling" using a combination of imaging techniques to precisely compare fat storage in cloned cells having the same fat genes expressed.

Single cell profiling allows researchers to precisely compare the inner workings of individual cells, whereas the conventional analytical approach in biochemistry measures entire populations of cells and then provides data representing an average.

"In this case, we don't want an average. We need to find out what causes fat storage at the single-cell level so that we can compare one cell to another, " Le said. "By profiling multiple events in single cells, we found that variability in fat storage is due to varied rates of insulin processing among cells."

The cell culture used in the research contains cloned mice fibroblast cells.

"This particular type of cell culture has been used to study the molecular control of obesity for the past 35 years," Cheng said. "Researchers have observed tremendous variability in how much fat is stored in cells with identical genes, but no one really knows why. Our findings have shed some light on this phenomenon."

The researchers used a specialized imaging method called coherent anti-Stokes Raman scattering, or CARS, combined with other techniques, including flow cytometry and fluorescence microscopy.

"This multimodal imaging system allows us to correlate different events, like fat storage, gene expression and insulin signaling," Le said. "We can monitor these different events at the same time, and that's why we can determine the mechanism at the single-cell level."

Insulin attaches to binding sites on cell membranes, signaling the cells to take up glucose from the blood. Cells that are said to be resistant to insulin fail to take up glucose, the primary cause of Type II diabetes, a medical condition affecting nearly 24 million Americans. About two-thirds of U.S. adults are overweight, and nearly one-third obese.

The research, which has been funded by the National Institutes of Health, is ongoing. Future work may seek to pinpoint specific events in the insulin-signaling cascade that are responsible for fat storage.

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu
Sources: Ji-Xin Cheng, (765) 494-4335, jcheng@purdue.edu
Thuc T. Le, (765) 496-9717, let@purdue.edu
Purdue News Service: (765) 494-2096; purduenews@purdue.edu

Emil Venere | EurekAlert!
Further information:
http://www.purdue.edu

More articles from Health and Medicine:

nachricht NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures
17.11.2017 | National Institute of Standards and Technology (NIST)

nachricht High speed video recording precisely measures blood cell velocity
15.11.2017 | ITMO University

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: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

NASA detects solar flare pulses at Sun and Earth

17.11.2017 | Physics and Astronomy

NIST scientists discover how to switch liver cancer cell growth from 2-D to 3-D structures

17.11.2017 | Health and Medicine

The importance of biodiversity in forests could increase due to climate change

17.11.2017 | Studies and Analyses

VideoLinks
B2B-VideoLinks
More VideoLinks >>>