Related Experiment Video
Updated: Jul 21, 2026
09:38
Dietary Supplementation of Polyunsaturated Fatty Acids in Caenorhabditis elegans
Published on: November 29, 2013
Polyunsaturated fatty acids stimulate hepatic UCP-2 expression via a PPARalpha-mediated pathway
1Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
American Journal of Physiology. Endocrinology and Metabolism
|November 10, 2001
Summary
Polyunsaturated fatty acids, like EPA, significantly increase uncoupling protein 2 (UCP-2) in liver cells. This UCP-2 regulation involves prostaglandins and PPARalpha, impacting energy metabolism.
Area of Science:
- Biochemistry
- Molecular Biology
- Metabolic Regulation
Background:
- Discovery of uncoupling protein (UCP) homologs UCP-2 and UCP-3 suggests a role in energy metabolism regulation.
- Fatty acids are known regulators of metabolic processes in hepatocytes.
Purpose of the Study:
- To investigate the hypothesis that UCP-2 expression in hepatocytes is regulated by fatty acids.
- To elucidate the specific fatty acids and signaling pathways involved in UCP-2 regulation.
Main Methods:
- Hepatocytes were treated with various fatty acids (palmitic, oleic, eicosapentaenoic acid [EPA], arachidonic acid) at specific concentrations.
- UCP-2 expression levels were measured over time (12-36 hours).
- The effect of aspirin and a peroxisome proliferator-activated receptor-alpha (PPARalpha) agonist (Wy-14643) on UCP-2 levels was assessed.
Main Results:
- Oleic acid showed a modest increase in UCP-2 expression.
- Eicosapentaenoic acid (EPA) induced a significant, concentration-dependent, and time-dependent upregulation of UCP-2 (up to 50-fold).
- Aspirin inhibited EPA-induced UCP-2 upregulation, implicating the prostaglandin pathway. Arachidonic acid also increased UCP-2 in an aspirin-inhibitable manner.
- The PPARalpha agonist Wy-14643 effectively stimulated UCP-2 mRNA levels, similar to EPA.
Conclusions:
- Polyunsaturated fatty acids, particularly EPA, are potent inducers of hepatic UCP-2.
- The upregulation of UCP-2 by polyunsaturated fatty acids appears to be mediated through a pathway involving prostaglandins and PPARalpha.
- These findings highlight a novel mechanism for regulating energy metabolism in hepatocytes via fatty acid signaling.
Related Concept Videos
03:38Structure of Lipids
Lipids include a diverse group of compounds that are largely nonpolar in nature. This is because they are hydrocarbons that include mostly nonpolar carbon-carbon or carbon-hydrogen bonds. Non-polar molecules are hydrophobic (“water fearing”), or insoluble in water. Lipids perform many different functions in a cell. Cells store energy for long-term use in the form of fats. Lipids also provide insulation from the environment for plants and animals. For example, they help keep aquatic birds and...
01:58Cell Specific Gene Expression
Multicellular organisms contain a variety of structurally and functionally distinct cell types, but the DNA in all the cells originated from the same parent cells. The differences in the cells can be attributed to the differential gene expression. Liver cells, whose functions include detoxification of blood, production of bile to metabolize fats, and synthesis of proteins essential for metabolism, must express a specific set of genes to perform their functions. Gene expression also varies with...
01:37The Unfolded Protein Response
The ER is the hub of protein synthesis in a cell. It has robust systems to quality control protein folding and also for degradation of terminally misfolded proteins. Under normal conditions, a small proportion of misfolded proteins that cannot be salvaged need to be transported to the cytoplasm by the ER-associated degradation or ERAD pathways. However, if the ERAD cannot handle the misfolded proteins, the cell activates the unfolded protein response or UPR to adjust the protein folding...
01:31Regulation of the Unfolded Protein Response
Inositol-requiring kinase one or IRE1 is the most conserved eukaryotic unfolded protein response (UPR) receptor. It is a type I transmembrane protein kinase receptor with a distinctive site-specific RNase activity. As the binding mechanics of the misfolded proteins with the N-terminal domain of IRE-1 are unclear, three binding models — direct, indirect, and allosteric -- are proposed for receptor activation. Nevertheless, it is known that once a misfolded protein associates with IRE1, it...
01:25Lipid Catabolism
Triglycerides serve as crucial long-term energy storage molecules in microorganisms, providing a dense source of metabolic energy. Their breakdown is mediated by lipases, which hydrolyze triglycerides into glycerol and free fatty acids. Each of these components follows distinct metabolic pathways, ultimately contributing to ATP synthesis and cellular energy homeostasis.Glycerol MetabolismGlycerol, released from triglyceride hydrolysis, is phosphorylated by glycerol kinase to form...
01:21Chronic Pancreatitis II: Pathophysiology
Chronic pancreatitis is a progressive and irreversible inflammation of the pancreas, most often caused by long-term alcohol abuse, but it can also be related to ductal obstruction, smoking, or genetic factors.Chronic pancreatitis occurs when the pancreas is repeatedly exposed to harmful agents like alcohol, smoking, ductal obstruction, or genetic predisposition. These factors lead to the release of toxic metabolites and inflammatory cytokines, sustaining chronic inflammation in the pancreatic...