title: Analysis of epididymal sperm maturation by MALDI profiling and top-down mass spectrometry.
abstract: The fertilization ability of male gametes is achieved after their transit through the epididymis where important post-gonadal differentiation occurs in different cellular compartments. Most of these maturational modifications occur at the protein level. The epididymal sperm maturation process was investigated using the ICM-MS (Intact Cell MALDI-TOF MS) approach on boar spermatozoa isolated from four different epididymal regions (immature to mature stage). Differential and quantitative MALDI-TOF profiling for whole cells or sub-cellular fractions was combined with targeted top-down MS in order to identify endogenous biomolecules. Using this approach, 172m/z peaks ranging between 2 and 20kDa were found to be modified during maturation of sperm. Using top-down MS, 62m/z were identified corresponding to peptidoforms/proteoforms with post-translational modifications (MS data are available via ProteomeXchange with identifier PXD001303). Many of the endogenous peptides were characterized as N-, C-terminal sequences or internal fragments of proteins presenting specific cleavages, suggesting the presence of sequential protease activities in the spermatozoa. This is the first time that such proteolytic activities could be evidenced for various sperm proteins through quantification of their proteolytic products. ICM-MS/top-down MS thus proved to be a valid approach for peptidome/degradome studies and provided new contributions to understanding of the maturation process of the male gamete involved in the development of male fertility.
  
  
  CONCLUSIONS
  This peptidomic study (i) characterized the peptidome of epididymal spermatozoa from boar (Sus scrofa); (ii) established characteristic molecular phenotypes distinguishing degrees of maturation of spermatozoa during epididymal transit, and (iii) revealed that protease activities were at the origin of numerous peptides from known and unknown proteins involved in sperm maturation and/or fertility processes.
authors.affiliation: INRA, Plateforme d'Analyse Intégrative des Biomolécules, Laboratoire de Spectrométrie de Masse, Nouzilly F-37380, France; INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly F-37380, France; CNRS, UMR7247, Nouzilly F-37380, France; Université François Rabelais de Tours, Tours F-37000, France; IFCE, Nouzilly F-37380, France. Electronic address: valerie.labas@tours.inra.fr.
authors.forename: Valérie
authors.initials: V
authors.lastname: Labas
authors.affiliation: INRA, Plateforme d'Analyse Intégrative des Biomolécules, Laboratoire de Spectrométrie de Masse, Nouzilly F-37380, France; INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly F-37380, France; CNRS, UMR7247, Nouzilly F-37380, France; Université François Rabelais de Tours, Tours F-37000, France; IFCE, Nouzilly F-37380, France.
authors.forename: Lucie
authors.initials: L
authors.lastname: Spina
authors.affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly F-37380, France; CNRS, UMR7247, Nouzilly F-37380, France; Université François Rabelais de Tours, Tours F-37000, France; IFCE, Nouzilly F-37380, France.
authors.forename: Clémence
authors.initials: C
authors.lastname: Belleannee
authors.affiliation: INRA, Plateforme d'Analyse Intégrative des Biomolécules, Laboratoire de Spectrométrie de Masse, Nouzilly F-37380, France; INRA, UMR1282 Infectiologie et Santé Publique, Nouzilly F-37380, France; Université François Rabelais de Tours, UMR1282 Infectiologie et Santé Publique, Tours F-37000, France.
authors.forename: Ana-Paula
authors.initials: AP
authors.lastname: Teixeira-Gomes
authors.affiliation: INRA, Plateforme d'Analyse Intégrative des Biomolécules, Laboratoire de Spectrométrie de Masse, Nouzilly F-37380, France; INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly F-37380, France; CNRS, UMR7247, Nouzilly F-37380, France; Université François Rabelais de Tours, Tours F-37000, France; IFCE, Nouzilly F-37380, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Gargaros
authors.affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly F-37380, France; CNRS, UMR7247, Nouzilly F-37380, France; Université François Rabelais de Tours, Tours F-37000, France; IFCE, Nouzilly F-37380, France.
authors.forename: Françoise
authors.initials: F
authors.lastname: Dacheux
authors.affiliation: INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly F-37380, France; CNRS, UMR7247, Nouzilly F-37380, France; Université François Rabelais de Tours, Tours F-37000, France; IFCE, Nouzilly F-37380, France.
authors.forename: Jean-Louis
authors.initials: JL
authors.lastname: Dacheux
mesh_terms: D000818:Animals; D004822:Epididymis / Q000378:metabolism; D005298:Fertility / Q000502:physiology*; D008297:Male; D059748:Proteolysis; D020543:Proteome / Q000378:metabolism*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013079:Sperm Maturation; D013094:Spermatozoa / Q000166:cytology / Q000378:metabolism*; D013552:Swine
chemical_list: D020543:Proteome
keywords: Degradome; Epididymis; ICM-MS; Peptidomic; Spermatozoa; Top-down