Rapid identification of plasmalogen molecular species using targeted multiplexed selected reaction monitoring mass spectrometry

Abul Kalam Azad; Hironori Kobayashi; Abdullah Md Sheikh; Harumi Osago; Hiromichi Sakai; Md Ahsanul Haque; Shozo Yano; Atsushi Nagai

doi:10.1016/j.jmsacl.2021.09.004

Rapid identification of plasmalogen molecular species using targeted multiplexed selected reaction monitoring mass spectrometry

J Mass Spectrom Adv Clin Lab. 2021 Oct 7:22:26-33. doi: 10.1016/j.jmsacl.2021.09.004. eCollection 2021 Nov.

Authors

Abul Kalam Azad^{1

2}, Hironori Kobayashi^{3

4}, Abdullah Md Sheikh⁴, Harumi Osago⁵, Hiromichi Sakai⁶, Md Ahsanul Haque^{4

7}, Shozo Yano⁴, Atsushi Nagai¹

Affiliations

¹ Department of Neurology, Faculty of Medicine, Shimane University, 89-1 Enya, Izumo 693-8501, Japan.
² Department of Microbiology, Jagannath University, Dhaka 1100, Bangladesh.
³ Department of Pediatrics, Faculty of Medicine, Shimane University, 89-1 Enya, Izumo 693-8501, Japan.
⁴ Department of Laboratory Medicine, Faculty of Medicine, Shimane University, 89-1 Enya, Izumo 693-8501, Japan.
⁵ Department of Biochemistry, Faculty of Medicine, Shimane University, 89-1 Enya, Izumo 693-8501, Japan.
⁶ Department of Biosignaling and Radioisotope Experiment, Faculty of Medicine, Shimane University, 89-1 Enya, Izumo 693-8501, Japan.
⁷ Department of Pharmacy, University of Asia Pacific, Dhaka 1205, Bangladesh.

Abstract

Plasmalogens (Pls) levels are reported to be altered in several neurological and metabolic diseases. Identification of sn-1 fatty alcohols and sn-2 fatty acids of different Pls species is necessary to determine the roles and mechanisms of action of Pls in different diseases. Previously, full-scan tandem mass spectrometry (MS/MS) was used for this purpose but is not effective for low-abundance Pls species. Recently, multiplexed selected reaction monitoring MS (SRM/MS) was found to be more selective and sensitive than conventional full-scan MS/MS for the identification of low-abundance compounds. In the present study, we developed a liquid chromatography (LC)-targeted multiplexed SRM/MS system for the identification and quantification of different Pls choline (Pls-PC) and Pls ethanolamine (Pls-PE) species. We determined five precursor-product ion transitions to identify sn-1 and sn-2 fragments of each Pls species. Consequently, sn-1 and sn-2 fatty acyl chains of 22 Pls-PC and 55 Pls-PE species were identified in mouse brain samples. Among them, some species had C20:0 and C20:1 fatty alcohols at the sn-1 position. For quantification of Pls species in mouse brain samples, a single SRM transition was employed. Thus, our results suggest that the LC-targeted multiplexed SRM/MS system is very sensitive for the identification and quantification of low-abundance lipids such as Pls, and is thus expected to make a significant contribution to basic and clinical research in this field in the future.

Keywords: CS, commercial standard; IS, internal standard; Identification; LC, liquid chromatography; LC-MS/MS; MS/MS, tandem mass spectrometry; MTBE, methyl tert-butyl ether; PLs, glycerophospholipids; PUFAs, polyunsaturated fatty acids; Phospholipids; Plasmalogens; Pls, plasmalogens; Pls-PC, plasmalogens choline; Pls-PE, plasmalogens ethanolamine; Quantification; RT, retention time; SRM, selected reaction monitoring; Targeted multiplexed SRM/MS‘.