An 8‑(Diazomethyl) Quinoline Derivatized Acyl-CoA in Silico Mass Spectral Library Reveals the Landscape of Acyl-CoA in Aging Mouse Organs

Acyl-Coenzyme As (acyl-CoAs) are
essential intermediates
to incorporate
carboxylic acids into the bioactive metabolic network across all species,
which play important roles in lipid remodeling, fatty acids, and xenobiotic
carboxylic metabolism. However, due to the poor liquid chromatographic
behavior, the relatively low mass spectrometry (MS) sensitivity, and
lack of authentic standards for annotation, the in-depth untargeted
profiling of acyl-CoAs is challenging. We developed a chemical derivatization
strategy of acyl-CoAs by employing 8-(diazomethyl) quinoline (8-DMQ)
as the labeling reagent, which increased the detection sensitivity
by 625-fold with good peak shapes. By applying the MS/MS fragmentation
rules learned from the MS/MS spectra of 8-DMQ-acyl-CoA authentic standards,
an 8-DMQ-acyl-CoA in silico mass spectral library containing 33,344
high-resolution tandem mass spectra of 8,336 acyl-CoA species was
created. The in silico library facilitated the high-throughput and
automatic annotation of acyl-CoA using multiple metabolomic data processing
tools, such as NIST MS Search and MSDIAL. The feasibility of the in
silico library in a complex sample was demonstrated by profiling endogenous
acyl-CoAs in multiple organs of an aging mouse. 53 acyl-CoA species
were annotated, including 12 oxidized fatty acyl-CoAs and 3 novel
nonfatty acyl-CoAs. False positive annotations were further screened
by developing an eXtreme Gradient Boosting (XGBoost) based retention
time prediction model. The organ distribution and the aging dynamics
of acyl-CoAs in a mouse model were discussed for the first time, which
helped to elucidate the organ-specific function of acyl-CoAs and the
role of different acyl-CoA species during aging.