Abstract
Nitrated phospholipids have recently been detected in vitro and in vivo and associated with beneficial health effects. They were identified and quantified in biological samples by lipidomics methodologies using liquid chromatography-collision-induced dissociation (CID) tandem mass spectrometry (MS/MS) acquired with the linear ion trap mass spectrometer. Only a few studies have used higher-energy collision dissociation (HCD)-MS/MS in high-resolution Orbitraps to characterize nitrated phosphatidylserines and nitrated cardiolipins, highlighting the marked differences in the fragmentation patterns when using CID or HCD fragmentation methods. In this study, we aimed to evaluate the fragmentation of nitrated phosphatidylcholine and nitrated phosphatidylethanolamine species under HCD-MS/MS. We studied the effect of normalized collision energy (NCE) in the fragmentation pattern to identify the best acquisition conditions and reporter ions to detect nitrated phospholipids. The results showed that the intensity of the typical neutral loss of nitrous acid (HNO2) diminishes with increasing NCE, becoming non-detectable for a higher NCE. Thus, the loss of HNO2 could not be the most suitable ion/fragment for the characterization of nitrated phospholipids under HCD. In HCD-MS/MS new fragment ions were identified, corresponding to the nitrated fatty acyl chains, NO2-RCOO−, (NO2-RCOOH-H2O + H)+, and (NO2-RCOOH + H)+, suggested as potential reporter ions to detect nitrated phospholipids when using the HCD-MS/MS lipidomics analysis.
Highlights
Phospholipids (PLs), mainly phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) are major constituents of cell membranes playing a crucial role in the integrity and function of membranes.PLs can react with reactive oxygen species (ROS) and reactive nitrogen species (RNS), leading to a plethora of structurally different and chemically diverse products
The nitrated and nitroxidized derivatives of PCs and PEs, the two main classes of PLs found in biological samples, were obtained using nitronium tetrafluoroborate (NO2 BF4 ) in a mimetic model of nitration mediated by RNS which occured in the hydrophobic environment of biological membranes [10,12]
We showed that the normalized collision energy (NCE) influenced the intensity of the reporter ions arising from the neutral loss (NL) of HNO2 (NL 47 Da), which are commonly used for the identification of nitrated and nitroxidized PLs in vitro and in vivo
Summary
Phospholipids (PLs), mainly phosphatidylcholines (PCs) and phosphatidylethanolamines (PEs) are major constituents of cell membranes playing a crucial role in the integrity and function of membranes.PLs can react with reactive oxygen species (ROS) and reactive nitrogen species (RNS), leading to a plethora of structurally different and chemically diverse products. On the other hand, nitrated PLs have only been reported recently in in vitro model systems and biological samples and structurally characterized by mass spectrometry (MS) approaches [10,11,12,13]. Nowadays, lipidomics studies are mainly carried out by LC-MS/MS using high-resolution instruments, including orbitrap analysers and higher-energy collisional dissociation (HCD) as fragmentation method [14,15,16,17]. Different fragmentation patterns can be obtained from these two different ion activation methods, CID and HCD, as previously reported for saccharides and peptides [18,19]. In the case of molecular lipid species, it has been described that the combined use of HCD and CID lead to complementary fragmentation patterns [17]. A recent study on the characterization of nitrated and nitroxidized derivatives of phosphatidylserine (PS), using
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
