Fatty acid test: Why some harm health, but others help
September 29, 2011 in Medical research
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."
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 September 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.
Provided by
University of California - San Diego
-
Intake of the right fatty acids can help to prevent heart attacks
Jun 30, 2011 |
not rated yet |
0
-
Columbia research shows novel benefits of fatty acids in arteries
Feb 05, 2009 |
not rated yet |
0
-
Trans-fatty acids and insulin sensitivity
Jul 08, 2008 |
not rated yet |
0
-
Altering Fatty Acid Levels in Diet May Reduce Prostate Cancer Growth Rate
Aug 01, 2006 |
not rated yet |
0
-
Pregnant mothers' diet linked to baby's obesity
Apr 04, 2008 |
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
-
Why is zone 1 in liver more prone to ischemic injury?
13 hours ago
-
How can there be villous adenoma in colon, if there are no villi there
May 22, 2013
-
How can there be a term called "intestinal metaplasia" of stomach
May 21, 2013
-
Pressure-volume curve: Elastic Recoil Pressure don't make sense
May 18, 2013
-
If you became brain-dead, would you want them to pull the plug?
May 17, 2013
-
MRI bill question
May 15, 2013
- More from Physics Forums - Medical Sciences
More news stories
Study reveals new mechanism for estrogen suppression of liver lipid synthesis
By discovering the new mechanism by which estrogen suppresses lipid synthesis in the liver, UC Irvine endocrinologists have revealed a potential new approach toward treating certain liver diseases.
Medical research
2 hours ago |
not rated yet |
0
|
MRI-based measurement helps predict vascular disease in the brain
Aortic arch pulse wave velocity, a measure of arterial stiffness, is a strong independent predictor of disease of the vessels that supply blood to the brain, according to a new study published in the June issue the journal ...
Medical research
2 hours ago |
not rated yet |
0
Antibiotics: A new understanding of sulfonamide nervous system side effects
Since the discovery of Prontosil in 1932, sulfonamide antibiotics have been used to combat a wide spectrum of bacterial infections, from acne to chlamydia and pneumonia. However, their side effects can include serious neurological ...
Medical research
4 hours ago |
not rated yet |
0
|
Scientists discover molecule triggers sensation of itch
Scientists at the National Institutes of Health report they have discovered in mouse studies that a small molecule released in the spinal cord triggers a process that is later experienced in the brain as the sensation of ...
Medical research
4 hours ago |
5 / 5 (1) |
0
|
Discarded immune cells induce the relocation of stem cells
Spanish researchers have discovered that the daily clearance of neutrophils from the body stimulates the release of hematopoietic stem cells from the bone marrow into the bloodstream, according to a report published today ...
Medical research
5 hours ago |
5 / 5 (1) |
0
Controlling mood through the motions of mitochondria
(Medical Xpress)—Regulating the distribution of power in neurons is done by a system that makes the national electric grid look simple by comparison. Each neuron has several thousand mitochondria confined ...
Future doctors unaware of their obesity bias
Two out of five medical students have an unconscious bias against obese people, according to a new study by researchers at Wake Forest Baptist Medical Center. The study is published online ahead of print in the Journal of ...
WHO: Scientific red tape mars efforts vs. virus
International efforts to combat a new pneumonia-like virus that has now killed 22 people are being slowed by unclear rules and competition for the potentially profitable rights to disease samples, the head ...
Research identifies a way to make cancer cells more responsive to chemotherapy
Breast cancer characterized as "triple negative" carries a poor prognosis, with limited treatment options. In some cases, chemotherapy doesn't kill the cancer cells the way it's supposed to. New research from Western University ...
Mayo Clinic genomic analysis lends insight to prostate cancer
Mayo Clinic researchers have used next generation genomic analysis to determine that some of the more aggressive prostate cancer tumors have similar genetic origins, which may help in predicting cancer progression. The findings ...
Shortage of key drug hampering U.S. efforts to control TB, report says
(HealthDay)—A shortage of a critical tuberculosis drug has hampered the efforts of health departments across the United States to contain the spread of the highly infectious lung disease, federal officials ...