Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Gladstone scientists identify target that may reduce complications of obesity

04.02.2010
Although obesity is a risk factor for diabetes and coronary heart disease worldwide, only some obese individuals go on to develop these metabolic complications, while others are relatively protected. Defining these protective factors could help scientists prevent disease in the wider population.

To this end, a research team at the Gladstone Institute of Cardiovascular Disease, led by Suneil Koliwad, MD, PhD, recently added new details that link obesity to diabetes and heart disease.

When individuals become obese from overeating, cells called adipocytes located in the fat tissue fill up with dietary fats and begin to die. Immune cells called macrophages move out of the blood stream and into this tissue, where they accumulate around dying adipocytes. As the macrophages work to clear away the dead cells, they are exposed to large amounts of dietary fat that can result in unwanted consequences. Exposure to saturated fats, in particular, causes the macrophages to enter an inflammatory state. In this state, the macrophages secrete cytokines, such as tumor necrosis factor (TNF) alpha, that encourage the development of insulin resistance, diabetes, and heart disease.

The Gladstone team hypothesized that enhancing the capacity of macrophages to store dietary fats might alter this process. To do this, they focused on an enzyme called DGAT1, which makes triglycerides from dietary fats for storage as cellular energy reserves.

They examined a transgenic strain of mice (aP2-Dgat1) that make large amounts of DGAT1 in both adipocytes and macrophages. On a high-fat diet, these mice became obese, but the macrophages in their fat tissue did not undergo inflammatory activation, and the mice were protected from developing systemic inflammation, insulin resistance, and fatty livers, all problems that were profound in the control mice.

Even more interesting was the team's finding that the protection against diet-induced inflammation and insulin resistance could be conferred on normal mice simply by replacing their macrophages with those from aP2-Dgat1 mice by bone marrow transplantation.

"We found in experimental mice that a single enzyme, DGAT1, in macrophages is involved in many of the problems associated with obesity," said Dr. Koliwad. "This is exciting because humans have this enzyme as well, providing the potential for a therapeutic target to examine."

Using cultured cells, the team also showed that increasing the amount of DGAT1 expressed by macrophages increased their capacity to store triglycerides and protected them against inflammatory activation by saturated fats. Moreover, DGAT1 expression was increased by treatment of macrophages with PPARgamma agonists, which are widely used agents to treat diabetes, and DGAT1 was required for these agents to protect macrophages against inflammatory activation induced by saturated fats.

"Our results are very exciting," said Dr. Robert Farese, senior author on the study. "We have used DGAT1 as a tool to uncover a mechanism by which macrophages might protect individuals from developing serious consequences of obesity."

Koliwad SK, Streeper RS, Monetti M, Cornelissen I, Chan L, Terayama K, Naylot S, Rao M, Hubbard B, Farese RV, Jr. Increased capacity for triacylglycerol synthesis in macrophages protects mice from deleterious consequences of diet-induced obesity. J. Clin. Invest., In press.

Robert V. Farese's primary affiliation is with the Gladstone Institute of Cardiovascular Disease, where he is senior investigator and where his laboratory is located and his research is conducted. He is also a professor of medicine, biochemistry and biophysics at the University of California, San Francisco.

About the Gladstone Institutes. The Gladstone Institutes is a nonprofit, independent research and educational institution, consisting of the Gladstone Institute of Cardiovascular Disease, the Gladstone Institute of Virology and Immunology and the Gladstone Institute of Neurological Disease. Independent in its governance, finances and research programs, Gladstone shares a close affiliation with UCSF through its faculty, who hold joint UCSF appointments.

Valerie Tucker | EurekAlert!
Further information:
http://www.ucsf.edu

More articles from Health and Medicine:

nachricht Study suggests possible new target for treating and preventing Alzheimer's
02.12.2016 | Oregon Health & Science University

nachricht The first analysis of Ewing's sarcoma methyloma opens doors to new treatments
01.12.2016 | IDIBELL-Bellvitge Biomedical Research Institute

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: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>