title: Proteomic analysis of seminal fluid from men exhibiting oxidative stress.
abstract: BACKGROUND
  Seminal plasma serves as a natural reservoir of antioxidants. It helps to remove excessive formation of reactive oxygen species (ROS) and consequently, reduce oxidative stress. Proteomic profiling of seminal plasma proteins is important to understand the molecular mechanisms underlying oxidative stress and sperm dysfunction in infertile men.
  
  
  METHODS
  This prospective study consisted of 52 subjects: 32 infertile men and 20 healthy donors. Once semen and oxidative stress parameters were assessed (ROS, antioxidant concentration and DNA damage), the subjects were categorized into ROS positive (ROS+) or ROS negative (ROS-). Seminal plasma from each group was pooled and subjected to proteomics analysis. In-solution digestion and protein identification with liquid chromatography tandem mass spectrometry (LC-MS/MS), followed by bioinformatics analyses was used to identify and characterize potential biomarker proteins.
  
  
  RESULTS
  A total of 14 proteins were identified in this analysis with 7 of these common and unique proteins were identified in both the ROS+ and ROS- groups through MASCOT and SEQUEST analyses, respectively. Prolactin-induced protein was found to be more abundantly present in men with increased levels of ROS. Gene ontology annotations showed extracellular distribution of proteins with a major role in antioxidative activity and regulatory processes.
  
  
  CONCLUSIONS
  We have identified proteins that help protect against oxidative stress and are uniquely present in the seminal plasma of the ROS- men. Men exhibiting high levels of ROS in their seminal ejaculate are likely to exhibit proteins that are either downregulated or oxidatively modified, and these could potentially contribute to male infertility.
authors.affiliation: Center for Reproductive Medicine, Glickman Urological and Kidney Institute, Cleveland Clinic, Cleveland, OH, USA. agarwaa@ccf.org.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Sharma
authors.forename: Ashok
authors.initials: A
authors.lastname: Agarwal
authors.forename: Gayatri
authors.initials: G
authors.lastname: Mohanty
authors.forename: Stefan S
authors.initials: SS
authors.lastname: Du Plessis
authors.forename: Banu
authors.initials: B
authors.lastname: Gopalan
authors.forename: Belinda
authors.initials: B
authors.lastname: Willard
authors.forename: Satya P
authors.initials: SP
authors.lastname: Yadav
authors.forename: Edmund
authors.initials: E
authors.lastname: Sabanegh
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000737:chemistry / Q000378:metabolism; D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D002853:Chromatography, Liquid; D019295:Computational Biology; D004249:DNA Damage; D006801:Humans; D007248:Infertility, Male / Q000378:metabolism; D008297:Male; D018384:Oxidative Stress; D040901:Proteomics; D017382:Reactive Oxygen Species / Q000378:metabolism; D012661:Semen / Q000737:chemistry / Q000378:metabolism*; D055101:Semen Analysis; D053719:Tandem Mass Spectrometry
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D017382:Reactive Oxygen Species