Valentina Murdica1, Greta Chiara Cermisoni2, Natasa Zarovni3, Andrea Salonia1,4, Paola Viganò5, Riccardo Vago1,4. 1. Urological Research Institute, Division of Experimental Oncology, IRCCS San Raffaele Scientific Institute, Milano, Italy. 2. Centro Scienze Natalità, Obstetrics and Gynecology Unit, IRCCS San Raffaele Scientific Institute, Milano, Italy. 3. Exosomics Siena S.p.A, Siena, Italy. 4. Università Vita-Salute San Raffaele, Milano, Italy. 5. Reproductive Sciences Laboratory, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milano, Italy.
Abstract
STUDY QUESTION: Are there differences in the proteomic profile of exosomes isolated from seminal plasma of normozoospermic (NSP) and severe asthenozoospermic (SA) men, potentially contributing to sperm features? SUMMARY ANSWER: A relevant group of proteins known to positively regulate sperm functions were over-represented in seminal exosomes of NSP men, i.e. cysteine-rich secretory protein-1 (CRISP1), while the inhibitory protein glycodelin was enriched in exosomes of SA subjects. WHAT IS KNOWN ALREADY: Exosomes are secreted along the male reproductive tract and are thought to be involved in spermatozoa maturation and function. Ejaculated spermatozoa are still able to capture exosomes; exosomes of NSP individuals improve sperm motility and prompt capacitation, while exosomes of SA men fail to exert similar features. STUDY DESIGN, SIZE, DURATION: Semen samples from NSP and SA men, aged 18 to 55 and registered at a single IVF center, were considered for this study project. Subjects were subdivided into three groups: a discovery cohort (five NSP men and six SA patients), a validation cohort (seven NSP and seven SA men) and the 'glycodelin analysis' cohort (20 NSP and 37 SA men). Exosomes were purified from semen of every participant. PARTICIPANTS/MATERIALS, SETTING, METHODS: Exosomes were characterized by nanoparticle tracking analysis, transmission electron microscopy and western blot. Comprehensive proteomics analysis of the exosomal proteome was performed by nanoscale liquid chromatographic tandem mass spectrometry analysis. Funrich software was used to determine statistical enrichment of pathways, networks and Gene Ontology terms of the identified proteins. Validation of differentially expressed proteins was performed through ELISA and western blot analysis. MAIN RESULTS AND THE ROLE OF CHANCE: The comprehensive proteomic analysis identified a total of 2138 proteins for both groups. There were 89 proteins found to be differentially expressed in exosomes of NSP versus SA subjects, of which 37 were increased in the NSP group and 52 were increased in the SA group. One-third of the exosomes-associated proteins highly expressed in NSP samples were involved in the reproductive process; conversely, the over-expressed proteins in exosomes of SA samples were not functionally specific. Quantitative data were confirmed on seminal exosomes from different cohorts of subjects. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Transfer of the proteins from exosomes to spermatozoa has been only partially demonstrated and up-take mechanisms are still poorly defined. WIDER IMPLICATIONS OF THE FINDINGS: Seminal exosomes carry proteins that are potentially able to either favour or inhibit the reproductive process in humans. A better understanding of these phenomena might pave the way for novel intervention measures in terms of male infertility. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the Italian Ministry of Health through an Institution Seed Grant. None of the authors has any competing interests.
STUDY QUESTION: Are there differences in the proteomic profile of exosomes isolated from seminal plasma of normozoospermic (NSP) and severe asthenozoospermic (SA) men, potentially contributing to sperm features? SUMMARY ANSWER: A relevant group of proteins known to positively regulate sperm functions were over-represented in seminal exosomes of NSP men, i.e. cysteine-rich secretory protein-1 (CRISP1), while the inhibitory protein glycodelin was enriched in exosomes of SA subjects. WHAT IS KNOWN ALREADY: Exosomes are secreted along the male reproductive tract and are thought to be involved in spermatozoa maturation and function. Ejaculated spermatozoa are still able to capture exosomes; exosomes of NSP individuals improve sperm motility and prompt capacitation, while exosomes of SAmen fail to exert similar features. STUDY DESIGN, SIZE, DURATION: Semen samples from NSP and SAmen, aged 18 to 55 and registered at a single IVF center, were considered for this study project. Subjects were subdivided into three groups: a discovery cohort (five NSP men and six SApatients), a validation cohort (seven NSP and seven SAmen) and the 'glycodelin analysis' cohort (20 NSP and 37 SAmen). Exosomes were purified from semen of every participant. PARTICIPANTS/MATERIALS, SETTING, METHODS: Exosomes were characterized by nanoparticle tracking analysis, transmission electron microscopy and western blot. Comprehensive proteomics analysis of the exosomal proteome was performed by nanoscale liquid chromatographic tandem mass spectrometry analysis. Funrich software was used to determine statistical enrichment of pathways, networks and Gene Ontology terms of the identified proteins. Validation of differentially expressed proteins was performed through ELISA and western blot analysis. MAIN RESULTS AND THE ROLE OF CHANCE: The comprehensive proteomic analysis identified a total of 2138 proteins for both groups. There were 89 proteins found to be differentially expressed in exosomes of NSP versus SA subjects, of which 37 were increased in the NSP group and 52 were increased in the SA group. One-third of the exosomes-associated proteins highly expressed in NSP samples were involved in the reproductive process; conversely, the over-expressed proteins in exosomes of SA samples were not functionally specific. Quantitative data were confirmed on seminal exosomes from different cohorts of subjects. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Transfer of the proteins from exosomes to spermatozoa has been only partially demonstrated and up-take mechanisms are still poorly defined. WIDER IMPLICATIONS OF THE FINDINGS: Seminal exosomes carry proteins that are potentially able to either favour or inhibit the reproductive process in humans. A better understanding of these phenomena might pave the way for novel intervention measures in terms of male infertility. STUDY FUNDING/COMPETING INTEREST(S): This study was funded by the Italian Ministry of Health through an Institution Seed Grant. None of the authors has any competing interests.
Authors: Hussein Kaddour; Steven Kopcho; Yuan Lyu; Nadia Shouman; Victor Paromov; Siddharth Pratap; Chandravanu Dash; Eun-Young Kim; Jeremy Martinson; Heather McKay; Marta Epeldegui; Joseph B Margolick; Jack T Stapleton; Chioma M Okeoma Journal: Cell Mol Life Sci Date: 2021-12-22 Impact factor: 9.207