title: Angiotensin II type 2 receptor is expressed in human sperm cells and is involved in sperm motility.
abstract: OBJECTIVE
  To investigate the presence of angiotensin II type 2 receptor (AT2R) in human spermatozoa and its implication in sperm fertility status.
  
  
  METHODS
  We carried out expression assays for AT2R by reverse transcription-polymerase chain reaction, Western blot, immunofluorescence, and flow cytometry techniques in human sperm cells. Percentage of AT2R-positive sperm cells was analyzed by flow cytometry.
  
  
  METHODS
  Assisted reproduction unit and academic research laboratory.
  
  
  METHODS
  Ninety-seven human semen samples from the Clínica IVI Bilbao.
  
  
  METHODS
  All samples were examined and classified according to World Health Organization guidelines. Spermatozoa were isolated from semen on discontinuous colloidal silica gradient (45%-90%) and swim-up techniques.
  
  
  METHODS
  Presence and location of the AT2R in spermatozoa and percentage of AT2R-positive sperm cells measured by flow cytometry.
  
  
  RESULTS
  We demonstrated the existence of AT2R and its transcript in human sperm by Western blot and reverse transcription-polymerase chain reaction. Immunofluorescence studies showed that AT2R is mainly located at the equatorial segment of the sperm head. The AT2R levels were associated with sperm motility parameters. Particularly, we found a significant positive correlation between AT2R and spermatozoa with progressive motility grade and a significant negative correlation with immotile spermatozoa, both in fresh semen samples and in prepared sperm cells. Regarding pathologic studies, the levels of AT2R measured by flow cytometry were lower in spermatozoa of asthenozoospermic men than in normozoospermic controls.
  
  
  CONCLUSIONS
  Angiotensin II type 2 receptor is present in human semen and may be involved in the control of sperm motility. In-depth understanding of the proteins involved in sperm motility can help to elucidate the role of these proteins in male infertility as well as to establish new biomarkers for male infertility.
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Gianzo
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain.
authors.forename: Iraia
authors.initials: I
authors.lastname: Muñoa-Hoyos
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain.
authors.forename: Itziar
authors.initials: I
authors.lastname: Urizar-Arenaza
authors.affiliation: IVI Clinic Bilbao, Leioa, Bizkaia, Spain.
authors.forename: Zaloa
authors.initials: Z
authors.lastname: Larreategui
authors.affiliation: IVI Clinic Bilbao, Leioa, Bizkaia, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Quintana
authors.affiliation: Laboratory of the Andrology and Semen Bank, IVI Clinic Valencia, Valencia, Spain.
authors.forename: Nicolás
authors.initials: N
authors.lastname: Garrido
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain. Electronic address: nerea.subiran@ehu.eus.
authors.forename: Nerea
authors.initials: N
authors.lastname: Subirán
authors.affiliation: Department of Physiology, Faculty of Medicine and Dentistry, University of the Basque Country (UPV/EHU), Leioa, Bizkaia, Spain.
authors.forename: Jon
authors.initials: J
authors.lastname: Irazusta
mesh_terms: D053627:Asthenozoospermia / Q000235:genetics / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D016022:Case-Control Studies; D005298:Fertility; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D008297:Male; D012333:RNA, Messenger / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D044139:Receptor, Angiotensin, Type 2 / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism* / Q000473:pathology
chemical_list: D015415:Biomarkers; D012333:RNA, Messenger; D044139:Receptor, Angiotensin, Type 2
keywords: Angiotensin II type 2 receptor; human; male fertility; sperm