Featured Research

from universities, journals, and other organizations

Turning white fat into energy-burning brown fat: Hope for new obesity and diabetes treatments

Date:
August 2, 2012
Source:
Columbia University Medical Center
Summary:
Medical researchers have identified a mechanism that can give energy-storing white fat some of the beneficial characteristics of energy-burning brown fat. The findings, based on studies of mice and of human fat tissue, could lead to new strategies for treating obesity and type 2 diabetes.

Researchers have identified a mechanism that can give energy-storing white fat some of the beneficial characteristics of energy-burning brown fat. The findings, based on studies of mice and of human fat tissue, could lead to new strategies for treating obesity and type 2 diabetes.
Credit: © Colinda McKie / Fotolia

Columbia University Medical Center (CUMC) researchers have identified a mechanism that can give energy-storing white fat some of the beneficial characteristics of energy-burning brown fat. The findings, based on studies of mice and of human fat tissue, could lead to new strategies for treating obesity and type 2 diabetes. The study was published August 2 in the online edition of the journal Cell.

Humans have two types of fat tissue: white fat, which stores excess energy in the form of triglycerides, and brown fat, which is highly efficient at dissipating stored energy as heat. Newborns have a relative abundance of brown fat, as protection against exposure to cold temperatures. In adults, however, almost all excess energy is stored as white fat.

"Turning white fat into brown fat is an appealing therapeutic approach to staunching the obesity epidemic, but it has been difficult to do so in a safe and effective way," said study leader Domenico Accili, MD, professor of Medicine and the Russell Berrie Foundation Professor at CUMC.

White fat can be "browned" with a class of drugs called thiazolidazines (TZDs), which increase the body's sensitivity to insulin. However, TZDs have many adverse effects -- including liver toxicity, bone loss, and, ironically, weight gain -- which have limited the use of these drugs.

The current study was undertaken to learn more about the function of TZDs, with the ultimate goal of developing better ways to promote the browning of white fat.

Scientists have known that TZDs promote the browning of white fat by activating a cell receptor called peroxisome proliferator-activated receptor-gamma (ppar-gamma), but the exact mechanism was not clear. To learn more, Dr. Accili and his colleagues studied a group of enzymes called sirtuins, which are thought to affect various biological processes, including metabolism.

The researchers had previously shown in mice that when sirtuin activity increases, so does metabolic activity. In the present study, they found that sirtuins boost metabolism by promoting the browning of white fat. "When we sought to identify how sirtuins promote browning, we observed many similarities between the effect of sirtuins and that of TZDs," said lead author Li Qiang, PhD, associate research scientist in Medicine at CUMC.

Sirtuins work by severing the chemical bonds between acetyl groups and proteins, a process known as deacetylation. "So the next question was whether sirtuins remove acetyl groups from ppar-gamma and, indeed, that was what we found," said Dr. Qiang.

To confirm that the deacetylation of ppar-gamma is crucial to the browning of fat, the researchers created a mutant version of ppar-gamma, in effect mimicking the actions of sirtuins. The mutation promoted the development of brown fat-like qualities in white fat.

"Our findings have two important implications," said Dr. Accili. "First, they suggest that TZDs may not be so bad -- if you can find a way to tweak their activity. Second, one way to tweak their activity is by using sirtuin agonists -- that is, drugs that promote sirtuin activity."

"The truth is, making sirtuin agonists has proved to be a real bear -- more promise than fact," he continued. "But now, for the first time, we have a biomarker for good sirtuin activity: the deacetylation of ppar-gamma. In other words, any substance that deacetylates ppar-gamma should in turn promote the browning of white fat and have a beneficial metabolic effect."

Dr. Accili's paper is titled, "Brown Remodeling of White Adipose Tissue by SirT1-Dependent Deacetylation of Ppar-gamma." The other contributors are Ning Kon (CUMC), Wenhui Zhao (CUMC), Sangkyu Lee (University of Chicago, Chicago, Illinois), Yiying Zhang (CUMC), Michael Rosenbaum (CUMC), Yingming Zhao (University of Chicago), Wei Gu (CUMC), and Stephen R. Farmer (Boston University School of Medicine, Boston, Mass.)

This research was supported by grants from the National Institutes of Health (HL087123, DK58282, DK64773, DK063608, and RR024156).


Story Source:

The above story is based on materials provided by Columbia University Medical Center. Note: Materials may be edited for content and length.


Journal Reference:

  1. Li Qiang, Liheng Wang, Ning Kon, Wenhui Zhao, Sangkyu Lee, Yiying Zhang, Michael Rosenbaum, Yingming Zhao, Wei Gu, Stephen R. Farmer, Domenico Accili. Brown Remodeling of White Adipose Tissue by SirT1-Dependent Deacetylation of Pparγ. Cell, 2012; 150 (3): 620 DOI: 10.1016/j.cell.2012.06.027

Cite This Page:

Columbia University Medical Center. "Turning white fat into energy-burning brown fat: Hope for new obesity and diabetes treatments." ScienceDaily. ScienceDaily, 2 August 2012. <www.sciencedaily.com/releases/2012/08/120802122305.htm>.
Columbia University Medical Center. (2012, August 2). Turning white fat into energy-burning brown fat: Hope for new obesity and diabetes treatments. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2012/08/120802122305.htm
Columbia University Medical Center. "Turning white fat into energy-burning brown fat: Hope for new obesity and diabetes treatments." ScienceDaily. www.sciencedaily.com/releases/2012/08/120802122305.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

House Republicans Vote to Sue Obama Over Healthcare Law

House Republicans Vote to Sue Obama Over Healthcare Law

Reuters - US Online Video (July 31, 2014) — The Republican-led House of Representatives votes to sue President Obama, accusing him of overstepping his executive authority in making changes to the Affordable Care Act. Mana Rabiee reports. Video provided by Reuters
Powered by NewsLook.com
Despite Health Questions, E-Cigs Are Beneficial: Study

Despite Health Questions, E-Cigs Are Beneficial: Study

Newsy (July 31, 2014) — Citing 81 previous studies, new research out of London suggests the benefits of smoking e-cigarettes instead of regular ones outweighs the risks. Video provided by Newsy
Powered by NewsLook.com
Dangerous Bacteria Kills One in Florida

Dangerous Bacteria Kills One in Florida

AP (July 31, 2014) — Sarasota County, Florida health officials have issued a warning against eating raw oysters and exposing open wounds to coastal and inland waters after a dangerous bacteria killed one person and made another sick. (July 31) Video provided by AP
Powered by NewsLook.com
Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins