title: Inter- and intra-organ spatial distributions of sea star saponins by MALDI imaging.
abstract: Saponins are secondary metabolites that are abundant and diversified in echinoderms. Mass spectrometry is increasingly used not only to identify saponin congeners within animal extracts but also to decipher the structure/biological activity relationships of these molecules by determining their inter-organ and inter-individual variability. The usual method requires extensive purification procedures to prepare saponin extracts compatible with mass spectrometry analysis. Here, we selected the sea star Asterias rubens as a model animal to prove that direct analysis of saponins can be performed on tissue sections. We also demonstrated that carboxymethyl cellulose can be used as an embedding medium to facilitate the cryosectioning procedure. Matrix-assisted laser desorption/ionization (MALDI) imaging was also revealed to afford interesting data on the distribution of saponin molecules within the tissues. We indeed highlight that saponins are located not only inside the body wall of the animals but also within the mucus layer that probably protects the animal against external aggressions. Graphical Abstract Saponins are the most abundant secondary metabolites in sea stars. They should therefore participate in important biological activities. Here, MALDI imaging is presented as a powerful method to determine the spatial distribution of saponins within the animal tissues. The inhomogeneity of the intra-organ saponin distribution is highlighted, paving the way for future elegant structure/activity relationship investigations.
authors.affiliation: Organic Synthesis and Mass Spectrometry Laboratory, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium.|Biology of Marine Organisms and Biomimetics, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium.
authors.forename: Marie
authors.initials: M
authors.lastname: Demeyer
authors.affiliation: Inserm U-1192, Laboratoire de Protéomique, Réponse Inflammatoire, Spectrométrie de Masse (PRISM), Université Lille 1, Cité Scientifique, 59655, Villeneuve D'Ascq, France. maxence.wisztorski@univ-lille1.fr.
authors.forename: Maxence
authors.initials: M
authors.lastname: Wisztorski
authors.affiliation: Organic Synthesis and Mass Spectrometry Laboratory, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium.
authors.forename: Corentin
authors.initials: C
authors.lastname: Decroo
authors.affiliation: Organic Synthesis and Mass Spectrometry Laboratory, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium.
authors.forename: Julien
authors.initials: J
authors.lastname: De Winter
authors.affiliation: Biology of Marine Organisms and Biomimetics, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Caulier
authors.affiliation: Biology of Marine Organisms and Biomimetics, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium.
authors.forename: Elise
authors.initials: E
authors.lastname: Hennebert
authors.affiliation: Biology of Marine Organisms and Biomimetics, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium.
authors.forename: Igor
authors.initials: I
authors.lastname: Eeckhaut
authors.affiliation: Inserm U-1192, Laboratoire de Protéomique, Réponse Inflammatoire, Spectrométrie de Masse (PRISM), Université Lille 1, Cité Scientifique, 59655, Villeneuve D'Ascq, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Fournier
authors.affiliation: Biology of Marine Organisms and Biomimetics, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium. Patrick.Flammang@umons.ac.be.
authors.forename: Patrick
authors.initials: P
authors.lastname: Flammang
authors.affiliation: Organic Synthesis and Mass Spectrometry Laboratory, University of Mons-UMONS, 23 Place du Parc, 7000, Mons, Belgium. pascal.gerbaux@umons.ac.be.
authors.forename: Pascal
authors.initials: P
authors.lastname: Gerbaux
mesh_terms: D000818:Animals; D047271:Asterias / Q000033:anatomy & histology* / Q000737:chemistry*; D012503:Saponins / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D012503:Saponins
keywords: MALDI-mass spectrometry imaging; Mass spectrometry; Saponin; Sea stars