Scientists discover switch that turns white fat brown
Scientists have discovered a biological switch that gives energy-storing white fat the characteristics of energy-burning brown fat. The findings could lead to new strategies for treating obesity.
The animal study by researchers at The Ohio State University Medical Center shows that the change is due to the activation of a nerve and biochemical pathway that begins in the hypothalamus, an area of the brain involved in energy balance, and ends in white fat cells. This pathway, called the hypothalamic-adipocyte axis, also induces brown-fat-like cells within masses of white fat.
The white-to-brown fat transformation occurs when animals are placed in an enriched environment, one with a variety of social and physical challenges.
The findings are published in the September issue of the journal Cell Metabolism.
"One of the holy grails of obesity therapy is to understand how to switch white fat to brown fat, and this study describes a new way to do exactly that," says study leader and researcher Dr. Matthew J. During, professor of neuroscience, of neurological surgery and of molecular virology, immunology and medical genetics. "Our findings suggest that we can potentially induce this transformation by modifying our lifestyle or by pharmacologically activating this brain-fat pathway."
Lead and corresponding author Dr. Lei Cao, assistant professor of molecular virology, immunology and medical genetics, notes that obesity is caused by a chronic energy surplus that is stored as lipid in white fat. "Increasing the output of energy is always attractive for obesity treatment, which is why the discovery of brown fat in adult humans caused much excitement a few years ago," she says.
"However, up to now the only known approach to inducing brown fat has been through exposure to chronic cold. Our research reveals a novel way of doing this without cold exposure. We show that animals living in an enriched environment become lean and resistant to diet-induced obesity, even in the presence of unlimited food." In 2010, During, Cao and their colleagues showed in a paper published in the journal Cell that this enrichment effect by itself curbed cancer growth in animals.
The current study used a similarly designed environment, with 15-20 mice housed in large containers equipped with running wheels, tunnels, huts, wood toys, a maze, and nesting material, in addition to unlimited food and water. Control mice were housed in groups of five in smaller, standard laboratory containers without toys but with unlimited food and water.
Key findings include the following:
- Enriched animals showed a significant reduction in abdominal white fat mass (49 percent less than controls).
- Exercise (running in a wheel) alone did not account for the changes in body composition and metabolism of enriched animals.
- Fed a high fat diet (45 percent fat), enriched animals gained 29 percent less weight than control mice and remained lean, with no change in food intake. Enriched animals also had a higher body temperature, suggesting that greater energy output, not suppressed appetite, led to the resistance to obesity.
The increased BDNF triggers sympathetic nervous signals to white fat masses in the body. These signals activate genes specific for brown fat such as Prdm16 and Ucp1, and suppress white-fat genes such as Resn. Blocking BDNF, on the other hand, inhibits or reverses the browning effect.
Overall, the study shows that environmental enrichment has an anti-obesity effect that involves the transformation of white fat to brown fat. That happens through a central mechanism called the hypothalamic-sympathoneural-adipocyte axis environmental enrichment stimulates the hypothalamus to produce the protein BDNF, increasing sympathetic nerve output to white fat, causing the "browning" of white fat and the burning of stored energy.
Next, During, Cao and their colleagues plan to identify which components of environmental enrichment sensory, cognitive, motor or social stimulation are essential for the browning effect.
Provided by Ohio State University Medical Center
- Fat chance: Brown vs. white fat cell specification May 14, 2008 | not rated yet | 0
- Housing upgrade shrinks tumors in mice with cancer Jul 08, 2010 | not rated yet | 0
- Turning 'bad' fat into 'good': A future treatment for obesity? May 03, 2011 | not rated yet | 0
- Molecular switch found in mice could lead to future obesity treatments Aug 20, 2008 | not rated yet | 0
- Control of blood vessels a possible weapon against obesity Jan 07, 2009 | not rated yet | 0
- Motion perception revisited: High Phi effect challenges established motion perception assumptions Apr 23, 2013 | 3 / 5 (2) | 2
- Anything you can do I can do better: Neuromolecular foundations of the superiority illusion (Update) Apr 02, 2013 | 4.5 / 5 (11) | 5
- The visual system as economist: Neural resource allocation in visual adaptation Mar 30, 2013 | 5 / 5 (2) | 9
- Separate lives: Neuronal and organismal lifespans decoupled Mar 27, 2013 | 4.9 / 5 (8) | 0
- Sizing things up: The evolutionary neurobiology of scale invariance Feb 28, 2013 | 4.8 / 5 (10) | 14
How can there be a term called "intestinal metaplasia" of stomach
10 hours ago Hello everyone, Ok Stomach's normal epithelium is simple columnar, now in intestinal type of adenocarcinoma of stomach it undergoes "intestinal...
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013 From pressure-volume curve of the lung and chest wall (attached photo), I don't understand why would the elastic recoil pressure of the lung is...
If you became brain-dead, would you want them to pull the plug?
May 17, 2013 I'd want the rest of me to stay alive. Sure it's a lousy way to live but it beats being all-the-way dead. Maybe if I make it 20 years they'll...
MRI bill question
May 15, 2013 Dear PFers, The hospital gave us a $12k bill for one MRI (head with contrast). The people I talked to at the hospital tell me that they do not...
Ratio of Hydrogen of Oxygen in Dessicated Animal Protein
May 13, 2013 As an experiment, for the past few months I've been consuming at least one portion of Jell-O or unflavored Knox gelatin per day. I'm 64, in very...
Alcohol and acetaminophen
May 13, 2013 Edit: sorry for the typo in the title , can't edit I looked around on google quite a bit and it's very hard to find precise information on the...
- More from Physics Forums - Medical Sciences
More news stories
Trends in Helicobacter pylori (H. pylori) and smoking explain a significant proportion of the decline of intestinal-type noncardia gastric adenocarcinoma (NCGA) incidence in US men between 1978 and 2008, and are estimated ...
Medical research 27 minutes ago | not rated yet | 0
Widely available in pharmacies and health stores, phosphatidylserine is a natural food supplement produced from beef, oysters, and soy. Proven to improve cognition and slow memory loss, it's a popular treatment for older ...
Medical research 5 hours ago | 5 / 5 (1) | 0 |
Researchers at Emory University have identified a protein that stimulates a pair of "orphan receptors" found in the brain, solving a long-standing biological puzzle and possibly leading to future treatments for neurological ...
Medical research 5 hours ago | not rated yet | 0 |
Australian scientists have charted the path of insulin action in cells in precise detail like never before. This provides a comprehensive blueprint for understanding what goes wrong in diabetes.
Medical research 6 hours ago | 4.7 / 5 (3) | 0 |
Researchers at the University of Illinois at Chicago College of Medicine will study gender differences in how the heart uses and stores fat—its main energy source—and how changes in fat metabolism play ...
Medical research 8 hours ago | not rated yet | 0
Activating an enzyme known to play a role in the anti-aging benefits of calorie restriction delays the loss of brain cells and preserves cognitive function in mice, according to a study published in the May ...
27 minutes ago | 5 / 5 (1) | 0 |
(HealthDay)—Three-quarters of public schools in the metro Atlanta area contain microbes, including bacteria indicating the presence of fecal matter, according to research published in the May 17 issue of ...
1 hour ago | not rated yet | 0
A paper recently published in the New England Journal of Medicine and co-written by physicians and scientists at the University of Colorado School of Medicine finds that an important genetic risk factor for pulmonary fibros ...
4 minutes ago | not rated yet | 0
Using the Department of Defense Serum Repository (DoDSR), University of Cincinnati (UC) researchers have identified a number of biomarkers for inflammatory bowel disease (IBD), which could help with earlier diagnosis and ...
6 minutes ago | not rated yet | 0
By studying the roles two proteins, thrombospondin-1 and prosaposin, play in discouraging cancer metastasis, a trans-Atlantic research team has identified a five-amino acid fragment of prosaposin that significantly reduces ...
7 minutes ago | not rated yet | 0
Transparent information on the evidence supporting global recommendations on paediatric medicines should be easily accessible in order to help policy makers decides on what drugs to include in their national drug lists, according ...
27 minutes ago | not rated yet | 0