TY - JOUR
T1 - Revising the structure of a new eicosanoid from human platelets to 8,9-11,12-diepoxy-13-hydroxy-eicosadienoic acid
AU - Kornilov, Andrei
AU - Kennedy, Paul D.
AU - Aldrovandi, Maceler
AU - Watson, Andrew
AU - Hinz, Christine
AU - Harless, Bryan
AU - Colombo, Joseph
AU - Maxey, Kirk M.
AU - Tyrrell, Victoria J.
AU - Simon, Matthew
AU - Aggarwal, Varinder K.
AU - Boeglin, William E.
AU - Brash, Alan R.
AU - Murphy, Robert C.
AU - O'donnell, Valerie B.
PY - 2019/6/7
Y1 - 2019/6/7
N2 - Eicosanoids are critical mediators of fever, pain and inflammation generated by immune and tissue cells. We recently described a new bioactive eicosanoid generated by cyclooxygenase-1 (COX-1) turnover during platelet activation that can stimulate human neutrophil integrin expression. On the basis of mass spectrometry (MS/MS and MS3), stable isotope labeling and GC/MS analysis, we previously proposed a structure of 8-hydroxy-9,11-dioxolane eicosatetraenoic acid (DXA3). Here, we achieved enzymatic synthesis and 1H-NMR characterization of this compound with results in conflict with the previously proposed structural assignment. Accordingly, by using LC-MS, we screened autoxidation reactions of 11-HpETE and thereby identified a candidate sharing the precise reverse phase chromatographic and MS characteristics of the platelet product. We optimized these methods to increase yield, allowing full structural analysis by 1H-NMR. The revised assignment is presented here as 8,9-11,12-diepoxy-13-hydroxy-eicosadienoic acid, abbreviated to 8,9-11,12-DiEp-13-HEDE or DiEpHEDE, substituted for the previous name DXA3. We found that in platelets, the lipid likely forms via dioxolane ring opening with rearrangement to the diepoxy moieties, followed by oxygen insertion at C13. We present its enzymatic biosynthetic pathway and MS/MS fragmentation pattern, and using the synthetic compound, demonstrate that it has bioactivity. For the platelet lipid, we estimate 16 isomers based on our current knowledge (and 4 isomers for the synthetic lipid). Determining the exact isomeric structure of the platelet lipid remains to be undertaken.
AB - Eicosanoids are critical mediators of fever, pain and inflammation generated by immune and tissue cells. We recently described a new bioactive eicosanoid generated by cyclooxygenase-1 (COX-1) turnover during platelet activation that can stimulate human neutrophil integrin expression. On the basis of mass spectrometry (MS/MS and MS3), stable isotope labeling and GC/MS analysis, we previously proposed a structure of 8-hydroxy-9,11-dioxolane eicosatetraenoic acid (DXA3). Here, we achieved enzymatic synthesis and 1H-NMR characterization of this compound with results in conflict with the previously proposed structural assignment. Accordingly, by using LC-MS, we screened autoxidation reactions of 11-HpETE and thereby identified a candidate sharing the precise reverse phase chromatographic and MS characteristics of the platelet product. We optimized these methods to increase yield, allowing full structural analysis by 1H-NMR. The revised assignment is presented here as 8,9-11,12-diepoxy-13-hydroxy-eicosadienoic acid, abbreviated to 8,9-11,12-DiEp-13-HEDE or DiEpHEDE, substituted for the previous name DXA3. We found that in platelets, the lipid likely forms via dioxolane ring opening with rearrangement to the diepoxy moieties, followed by oxygen insertion at C13. We present its enzymatic biosynthetic pathway and MS/MS fragmentation pattern, and using the synthetic compound, demonstrate that it has bioactivity. For the platelet lipid, we estimate 16 isomers based on our current knowledge (and 4 isomers for the synthetic lipid). Determining the exact isomeric structure of the platelet lipid remains to be undertaken.
KW - Immunity
KW - leukocyte-regulating lipid
KW - 8-hydroxy-9,11- dioxolane eicosatetraenoic acid (DXA3)
KW - 8,9-11,12-diepoxy-13-hydroxy-eicosadienoic acid (8,9-11,12-DiEp-13-HEDE)
KW - DiEpHEDE
KW - eicosanoid
KW - lipid metabolism
KW - cyclooxygenase (COX)
KW - platelet
KW - lipid
UR - http://www.scopus.com/inward/record.url?scp=85066955267&partnerID=8YFLogxK
U2 - 10.1074/jbc.RA119.008915
DO - 10.1074/jbc.RA119.008915
M3 - Article (Academic Journal)
C2 - 31061099
SN - 0021-9258
VL - 294
SP - 9225
EP - 9238
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 23
ER -