Featured Research

from universities, journals, and other organizations

Fatty acid test: Why some harm health, but others help

Date:
October 3, 2011
Source:
University of California - San Diego
Summary:
In a new paper, researchers offer an explanation, and a framework that could lead to dietary supplements designed to treat obesity at the molecular level.

A major risk factor for cardiovascular disease, type 2 diabetes and other health- and life-threatening conditions, obesity is epidemic in the United States and other developed nations where it's fueled in large part by excessive consumption of a fat-rich "Western diet."

Related Articles


But not all fats are equal. Animal-derived saturated fats like lard and butter are strongly linked to adverse health effects, but unsaturated and polyunsaturated fats from plants and cold-water fish like salmon and mackerel are not. In fact, the latter are known to produce beneficial health effects and can reduce the risk of cardiovascular disease and diabetes.

For biomedical investigators, the enduring question has been why saturated and unsaturated fatty acids produce such diametrically opposed health effects. Now, in a paper published in the Sept. 30 issue of the journal Cell, researchers at the University of California San Diego School of Medicine and colleagues offer an explanation, and a framework that could lead to dietary supplements designed to treat obesity at the molecular level.

"These findings not only explain the long-standing enigma regarding the differential health effects of saturated and unsaturated fatty acids," said senior author Michael Karin, PhD, Distinguished Professor of Pharmacology in UC San Diego's Laboratory of Gene Regulation and Signal Transduction, "they also provide improved tools and a mechanistic framework for the potential development of dietary supplements to treat obesity, estimated to be worth billions of dollars per year."

Senior author Karin, first author Ryan G. Holzer, PhD, formerly a graduate student in Karin's lab and now at the Mayo Clinic, and colleagues began with the observation that saturated fatty acids, such as palmitic acid, are potent activators of Jun kinases (JNK), key regulatory molecules implicated in the development of type 2 diabetes, insulin resistance, obesity and atherosclerosis. However, unsaturated fatty acids such as palmitoleic acid (POA) and eicosapentaenoic acid (EPA) not only do not activate JNK, but actually block JNK activation by palmitic acid.

Palmitic acid and POA differ in molecular structure by the presence of a single unsaturated bond (the absence of two hydrogen atoms) in POA. Cellular membrane fluidity is decreased upon incorporation of saturated fatty acids, which possess rigid hydrocarbon tails, but increased by the incorporation of unsaturated fatty acids with "bent" hydrocarbon tails.

Postulating that the membrane is the only cellular structure that can discriminate between all of these fatty acids, the scientists searched for membrane-associated protein kinases that could account for the differential effects on JNK activity. They ultimately identified c-Src, a membrane-associated tyrosine kinase, as the molecule responsible for activation of JNK by palmitic acid and other saturated fatty acids. They also discovered that saturated fatty acids "push" c-Src into membrane sub-domains of reduced fluidity and increased rigidity, where it accumulates in an activated form that eventually leads to JNK activation.

By contrast, POA and EPA prevent these changes in the membrane distribution of c-Src and -- by blocking c-Src aggregation -- they inhibit its activation by saturated fatty acids.

Most of the research was conducted using cultured cells (fibroblasts) treated with individual or combined fatty acids, but the scientists also fed mice a high-fat diet (in which 60 percent of the calories were fat-derived) and reported similar c-Src accumulation within membrane subdomains of increased rigidity and JNK activation.

Currently, polyunsaturated fatty acids, such as EPA and structurally-related omega-3 fatty acids are used in the treatment of hyperlipidemia (high blood cholesterol levels) and may be effective in the treatment or prevention of type 2 diabetes. Karin said understanding how EPA works could lead to the identification of even more potent EPA-like molecules.

Funding for this research came from the National Institutes of Health, the Superfund Basic Research Program and the American Diabetes Association.

Co-authors of the paper are Eek-Joong Park, Ning Li, Helen Tran, Monica Chen and Crystal Choi, Laboratory of Gene Regulation and Signal Transduction, Department of Pharmacology, UC San Diego; and Giovanni Solinas, Laboratory of Metabolic Stress Biology, Department of Medicine, Physiology, University of Fribourg, Switzerland.


Story Source:

The above story is based on materials provided by University of California - San Diego. The original article was written by Scott LaFee. Note: Materials may be edited for content and length.


Journal Reference:

  1. Ryan G. Holzer, Eek-Joong Park, Ning Li, Helen Tran, Monica Chen, Crystal Choi, Giovanni Solinas, Michael Karin. Saturated Fatty Acids Induce c-Src Clustering within Membrane Subdomains, Leading to JNK Activation. Cell, 2011; 147 (1): 173-184 DOI: 10.1016/j.cell.2011.08.034

Cite This Page:

University of California - San Diego. "Fatty acid test: Why some harm health, but others help." ScienceDaily. ScienceDaily, 3 October 2011. <www.sciencedaily.com/releases/2011/09/110929122800.htm>.
University of California - San Diego. (2011, October 3). Fatty acid test: Why some harm health, but others help. ScienceDaily. Retrieved December 22, 2014 from www.sciencedaily.com/releases/2011/09/110929122800.htm
University of California - San Diego. "Fatty acid test: Why some harm health, but others help." ScienceDaily. www.sciencedaily.com/releases/2011/09/110929122800.htm (accessed December 22, 2014).

Share This


More From ScienceDaily



More Health & Medicine News

Monday, December 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Touch-Free Smart Phone Empowers Mobility-Impaired

Touch-Free Smart Phone Empowers Mobility-Impaired

Reuters - Innovations Video Online (Dec. 21, 2014) A touch-free phone developed in Israel enables the mobility-impaired to operate smart phones with just a movement of the head. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Earthworms Provide Cancer-Fighting Bacteria

Earthworms Provide Cancer-Fighting Bacteria

Reuters - Innovations Video Online (Dec. 21, 2014) Polish scientists isolate bacteria from earthworm intestines which they say may be used in antibiotics and cancer treatments. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Existing Chemical Compounds Could Revive Failing Antibiotics, Says Danish Scientist

Reuters - Innovations Video Online (Dec. 21, 2014) A team of scientists led by Danish chemist Jorn Christensen says they have isolated two chemical compounds within an existing antipsychotic medication that could be used to help a range of failing antibiotics work against killer bacterial infections, such as Tuberculosis. Jim Drury went to meet him. Video provided by Reuters
Powered by NewsLook.com
Hugging It Out Could Help You Ward Off A Cold

Hugging It Out Could Help You Ward Off A Cold

Newsy (Dec. 21, 2014) Carnegie Mellon researchers found frequent hugs can help people avoid stress-related illnesses. Video provided by Newsy
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:

Strange & Offbeat Stories


Health & Medicine

Mind & Brain

Living & Well

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