Structural library and visualization of endogenously oxidized phosphatidylcholines using mass spectrometry-based techniques

Abstract

Although oxidized phosphatidylcholines (oxPCs) play critical roles in numerous pathological events, the type and production sites of endogenous oxPCs remain unknown because of the lack of structural information and dedicated analytical methods. Herein, a library of 465 oxPCs is constructed using high-resolution mass spectrometry-based non-targeted analytical methods and employed to detect 70 oxPCs in mice with acetaminophen-induced acute liver failure. We show that doubly oxygenated polyunsaturated fatty acid (PUFA)-PCs (PC PUFA;O2), containing epoxy and hydroxide groups, are generated in the early phase of liver injury. Hybridization with in-vivo 18O labeling and matrix-assisted laser desorption/ionization-tandem MS imaging reveals that PC PUFA;O2 are accumulated in cytochrome P450 2E1-expressing and glutathione-depleted hepatocytes, which are the major sites of liver injury. The developed library and visualization methodology should facilitate the characterization of specific lipid peroxidation events and enhance our understanding of their physiological and pathological significance in lipid peroxidation-related diseases.

Development of an Automatic Ultrasonic Matrix Sprayer for Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry Imaging

“…Matrix selecting and matrix deposition are crucial steps for preparation of samples before MALDI MSI. Various matrixes, such as α-cyano-4-hydroxycinnamic acid (CCA) , and 2,5-dihydroxybenzoic acid (DHB) , for analysis in positive mode; 9-aminoacridine (9-AA), , 1,5-naphthalenediamine dihydrochloride (1,5-DANHCl), N-(1-naphthyl)­ethylenediamine dihydrochloride (NEDC), , and nitrogen- and sulfur-co-doped carbon dots (N,S-co-doped CDs) for analysis in negative mode; and 1,5-naphthalenediamine (1,5-DAN) , and 3-aminophthalhydrazide (Luminol) for dual-polarity detection, have been used for MALDI MSI in recent years. However, the size and homogeneity of the matrix crystal on the surface of the tissue section to a large extent affect the repeatability, sensitivity, spatial resolution, and finally, the overall quality of MALDI MS ion images.…”

Analytical and computational workflow for in-depth analysis of oxidized complex lipids in blood plasma

“…Unfortunately, chemically defined standards of oxidized complex lipids necessary to create a fragment spectra library, are limited to just a few commercially available molecular species and do not reflect the diversity of possible endogenous analytes. To facilitate further high-throughput annotation of oxGPLs, we compiled our results obtained by MS3 and elevated energy stepped HCD MS2 fragmentation of selected oxylipin standards and in vitro oxidized PC lipids (Supplementary Data 1.1 and 1.2 ), literature data on the fragmentation of oxidized free fatty acids and complex lipids 20 , 22 , 26 – 34 , as well as available MS2 spectra from METLIN, LIPID MAPS, and MS DIAL.msp library, in the form of fragmentation rules exemplified here for different modification types and positions on oxidized oleoyl (18:1), linoleoyl (18:2), and arachidonoyl (20:4) chains in PC lipids (Supplementary Data 2 ).…”

Phospholipid peroxidation-driven modification of chondrogenic transcription factor mediates alkoxyl radicals-induced impairment of embryonic bone development

“…These findings are in line with a previous report showing that iron overload resulting from upregulation of iron transporters, resulted in changes in bone microarchitecture and bone loss [ 64 ]. Yamada et al used a cell-free system to show that while AAPH autoxidation resulted in an excessive accumulation of lipid hydroperoxides, iron and other metal ions further promoted the transformation of lipid hydroperoxides to many secondary oxidative products, thus amplifying lipid peroxidation [ 29 ]. These observations are in harmony with the collaborative mode of alkoxyl radicals and iron identified in our study.…”

“…2,2′-azobis [2-methylpropionamidine] dihydrochloride (AAPH), a classical generator of alkoxyl radicals, is extensively utilized in oxidative stress-related in vivo and in vitro studies [ 24 , 25 ], including studies on embryonic development [ [26] , [27] , [28] ]. In particular, it is worth noting that AAPH has been shown to initiate the oxidation of PUFAs-PL in cell-free conditions [ 29 , 30 ], whereas the presence of iron further enhances the decomposition of lipid hydroperoxides to a wide variety of secondary oxidation products [ 29 , 31 ]. Based on the above, in the present study, we took advantage of AAPH to obtain insights into the precise mechanism of alkoxyl radicals-induced defective bone development in chicken embryos.…”