Figure 5.

Proposed biosynthesis scheme for protectin D1 (PD1) and aspirin-triggered protectin D1 (AT-PD1). DHA is first converted to 17S-HpDHA intermediate by 15-LOX. Then PD1 is generated through 16S, 17S-epoxide. In the aspirin-triggered pathway, 17R-HpDHA is generated from DHA via acetylated-COX, and converted to AT-PD1 via a 16R, 17R-containing epoxide intermediate. Both PD1 and AT-PD1 reduce leukocytes and PMN infiltration in peritonitis stimulated by either TNF-α or zymosan A. PD1 and AT-PD1 each enhance human macrophage efferocytosis of apoptotic human PMNs and limit human PMN transmigration across human endothelial cells, the defining pro-resolving bioactions.