Fig 3. AsPC-1 exosomes are enriched in arachidonic acid and exosomal arachidonic acid contributes to the efficiency of AsPC-1 exosome-macrophage fusion.

(A) Compared to exosomes from other PDAC cell lines and from HPDE cells, AsPC-1 exosomes are enriched in arachidonic acid (C20:4) species. Comparison of the percent of arachidonic acid in each glycerophospholipid class showing that the percentage of AA is highest in the PI and PE fractions. Phosphatidylcholine = PC, phosphatidylserine = PS, phosphatidylethanolamine = PE, phosphatidic acid = PA, phosphatidylinositol = PI. (B) Representative fusion curves of exosomes with non-polarized THP-1 macrophages. (C) Compared with exosomes from other pancreatic cell lines, AsPC-1 exosomes fuse at the highest rate with THP-1-derived macrophages. Relative arachidonic acid (AA) levels shown with plus signs. (D, E) Pre-treatment of AsPC-1 exosomes with phospholipase A₂ (PLA₂), which removes AA from phospholipids, decreased the exosome fusion rate. Data from three independent experiments are represented as mean ± SEM. *****p<0.0005 by ANOVA.