Elevated SPM biosynthesis in apoptotic PMNs. PMNs were isolated from peripheral blood of healthy volunteers and placed directly in MeOH (PMN), induced to apoptose (Apo PMN), or stimulated with zymosan (PMN + Zy). After extraction, LM profiles were obtained using LC-MS/MS (see “Sample extraction and lipid mediator metabololipidomics”). (A) Representative MRM chromatograms of the LM identified in the apoptotic or Zy-activated neutrophils. Peak heights represent the relative levels of each LM. Cumulative levels for individual LM families are depicted as a function of color intensity, where color scales (eg, white to blue [Apo PMN = ] or white to tan [Zy PMN = ]) are set from zero to 500 pg per 5 × 10⁶ cells. (B) Accompanying MS/MS spectra used for identification. (C) Lipid mediator and precursor/pathway marker transition where: Q1, M-H (parent ion); and Q3, diagnostic ion in the MS-MS (daughter ion), along with mean ± SEM values for each of the mediators identified. Values are for 5 × 10⁶ PMNs. The detection limit was ∼ 1 pg. *Below limits. Cumulative values: (D) Leukotriene B₄ (and 20-OH LTB₄ metabolite). (E) D-series resolvins, protectins, and maresins. (F) Lipoxins. (G) E-series resolvins and lipoxins. (H) Prostaglandins and thromboxanes. (C-H) Results are expressed as mean ± SEM; n = 5 distinct cell preparations. *P < .05 vs PMNs. **P < .01 vs PMNs. ***P < .01 vs PMNs. #P < .05 vs Apo PMNs.