Identification of an antibacterial polypeptide in mouse seminal vesicle secretions

J Reprod Immunol. 2021 Nov:148:103436. doi: 10.1016/j.jri.2021.103436. Epub 2021 Oct 19.

Abstract

In both men and women, pathogenic bacteria enter the reproductive tract and cause harmful symptoms. Intrauterine and oviductal inflammation after copulation may have severe effects, such as infertility, implantation failure, oviduct obstruction, and robust life-threatening bacterial infection. Human seminal plasma is considered to be protective against bacterial infection. Among its components, Semenogelin-I/-II proteins are digested to function as bactericidal factors; however, their sequences are not conserved in mammals. Therefore, alternative antibacterial (bactericidal and/or bacteriostatic) systems may exist across mammals. In this study, we examined the antibacterial activity in the seminal plasma of mice lacking a gene cluster encoding Semenogelin-I/-II counterparts. Even in the absence of the majority of seminal proteins, antibacterial activity remained in the seminal plasma. Moreover, a combination of gel chromatography and liquid chromatography coupled with tandem mass spectrometry revealed that the prostate and testis expressed 4 protein as a novel antibacterial (specifically, bacteriostatic) protein, the sequence of which is broadly conserved across mammals. Our results provide the first evidence of a bacteriostatic protein that is widely present in the mammalian seminal plasma.

Keywords: Antibacterial activity; Bacteriostasis; PATE4; SVS7; Seminal plasma; Seminal vesicle secretion.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / metabolism*
  • Bodily Secretions
  • Conserved Sequence
  • Female
  • Humans
  • Male
  • Mammals / genetics
  • Mice
  • Mice, Inbred C57BL
  • Mice, Mutant Strains
  • Secretory Vesicles / metabolism*
  • Semen / metabolism*
  • Seminal Vesicle Secretory Proteins / genetics
  • Seminal Vesicle Secretory Proteins / metabolism*

Substances

  • Anti-Bacterial Agents
  • Pate4 protein, mouse
  • Seminal Vesicle Secretory Proteins
  • seminal vesicle-specific antigen