Protectin D1

Protectin D1 also known as neuroprotectin D1 (when it acts in the nervous system) and abbreviated most commonly as PD1 or NPD1 is a member of the class of specialized proresolving mediators. Like other members of this class of polyunsaturated fatty acid metabolites, it possesses strong anti-inflammatory, anti-apoptotic and neuroprotective activity. PD1 is an aliphatic acyclic alkene 22 carbons in length with two hydroxyl groups at the 10 and 17 carbon positions and one carboxylic acid group at the one carbon position.

Specifically, PD1 is an endogenous stereoselective lipid mediator classified as an autocoid protectin. Autacoids are enzymatically derived chemical mediators with distinct biological activities and molecular structures. Protectins are signaling molecules that are produced enzymatically from unsaturated fatty acids. Their molecular structure is characterized by the presence of a conjugated system of double bonds. PD1, like other protectins, is produced by the oxygenation of the ω-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) and it is found in many tissues, such as the retina, the lungs and the nervous system.

PD1 has a significant role as an anti-inflammatory, anti-apoptotic and neuroprotective molecule. Studies in Alzheimer's disease animal models, in stroke patients and in human retina pigment epithelial cells (RPE) have shown that PD1 can potentially reduce inflammation induced by oxidative stress and inhibit the pro-apoptotic signal, thereby preventing cellular degeneration. Finally, recent studies examining the pathogenicity of influenza viruses, including the avian flu (H5N1), have suggested that PD1 can potentially halt the proliferation of the virus, thus protecting respiratory cells from lethal viral infections.