Spatial segmentation and metabolite annotation involved in sperm maturation in the rat epididymis by MALDI imaging mass spectrometry

AbstractSpermatozoa acquire their fertilizing capacity during a complex maturation process that occurs in the epididymis. This process involves a substantial molecular remodeling at the surface of the gamete. Epididymis is divided into three regions (the caput, corpus, and cauda) or into 19 intra ‐regional segments based on histology. Most studies carried out on epididymal maturation has been performed on sperm samples or tissue extracts. Here, we used MALDI imaging mass spectrometry (IMS) in the positive and negative ion modes combined with spatial segmentation and automated metabolite an notation to study the precise localization of metabolites directly in the rat epididymis. The spatial segmentation revealed that the rat epididymis could be divided into several molecular clusters different from the 19 intra‐regional segments. The discriminative m/z values that contributed the mos t to each molecular cluster were then annotated and corresponded mainly to phosphatidylcholines, sphingolipids, glycerophosphates, triacylglycerols, plasmalogens, phosphatidylethanolamines and lysophosphatidylcholines. A substantial remodeling of lipid composition during epididymal maturation was ob served. It was characterized in particular by an increase in the number of sphingolipids and plasmalogens and a decrease in the proportion of triacylglycerols annotated from caput to cauda. Ion images reveal that molecules belonging to the same family can have very different localizations along the...

Source: Journal of Mass Spectrometry - July 26, 2020 Category: Chemistry Authors: M élanie Lagarrigue, Régis Lavigne, Blandine Guével, Andrew Palmer, Karine Rondel, Laetitia Guilot, Jan H. Kobarg, Dennis Trede, Charles Pineau Tags: RESEARCH ARTICLE Source Type: research