http://www.lipidomicnet.org/index.php?title=Prostaglandins_(FA0301)&diff=prev&oldid=2260
+ omega 3 --> < PGD2, > PGD3. C'è caso che la PGD3 sia un antagonista della PGD2.
Author Summary
Inflammation is a physiological response to tissue trauma or infection. Neutrophils, which circulate in the blood stream, are the first inflammatory cells to be recruited to a site of tissue inflammation. In response to recruitment signals provided by chemotactic peptides called chemo- kines, neutrophils traverse the endothelial cell lining of blood vessels. This process involves a multistep cascade of neutrophil adhesion and activation events on the endo- thelial barrier. While investigating the anti-inflammatory functions of the omega-3 fatty acid , EPA, which is found, for instance, in dietary fish oil, we identified an additional unexpected lipid-derived signal that is essential for neutrophil migration across the endothelium. Our exper- iments show that a chemokine delivered the first signal needed to bind neutrophils firmly to the endothelial surface. However, in order to traverse the endothelium, a subsequent signal delivered by prostaglandin-D2 (PGD2), a lipid derived from the omega-6 fatty acid arachidonic acid, was essential. When EPA, was introduced into the experiment, it was used to form PGD3. This alternative lipid blocked interactions between PGD2 and its receptor on neutrophils, preventing the process of migration across the endothelial barrier. Thus, we reveal a new step in the recruitment of neutrophils during inflammation, and a novel anti-inflammatory mechanism of action of dietary EPA.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2718617/pdf/pbio.1000177.pdf