title: A proteomic (SELDI-TOF-MS) approach to estrogen agonist screening.
abstract: A small fish model and surface-enhanced laser desorption/ionization time-of-flight mass spectrometry were used to investigate plasma protein expression as a means to screen chemicals for estrogenic activity. Adult male sheepshead minnows (Cyprinodon variegatus) were placed into aquaria for seawater control, solvent control, and treatments of 17beta-estradiol (E2), methoxychlor (MXC), bisphenol-A (BPA), 4-tert-pentylphenol (TPP), endosulfan (ES), and chlorpyriphos (CP). Fish plasma was applied to weak cation exchange (CM10) ProteinChip arrays, processed, and analyzed. The array produced approximately 42 peaks for E2 plasma and 30 peaks for solvent control plasma. Estrogen-responsive mass spectral biomarker peaks were identified by comparison of E2-treated and control plasma spectra. Thirteen potential protein biomarkers with a range from 1 to 13 kDa were up- or downregulated in E2-treated fish and their performance as estrogenic effects markers was evaluated by comparing spectra from control, estrogen agonist, and nonagonist stressor-treated males and normal female fish plasma. One of the biomarkers, mass-to-charge ratio 3025.5, was identified by high-resolution tandem mass spectrometry as C. variegatus zona radiata protein, fragment 2. The weak environmental estrogens MXC, BPA, and TPP elicited protein expression profiles consistent with the estrogen expression model. Estrogen-responsive peaks were not detected in plasma from fish in the seawater, vehicle, ES, or CP treatments. No difference was found between plasma protein expression of seawater control and solvent control fish. We show that water exposure of fish to estrogen agonists produces distinct plasma protein biomarkers that can be reproducibly detected at low levels using protein chips and mass spectrometry.
authors.affiliation: US Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Gulf Ecology Division, Gulf Breeze, FL 32561, USA. walker.calvin@epa.gov
authors.forename: Calvin C
authors.initials: CC
authors.lastname: Walker
authors.forename: Kimberly A
authors.initials: KA
authors.lastname: Salinas
authors.forename: Peggy S
authors.initials: PS
authors.lastname: Harris
authors.forename: Sherry S
authors.initials: SS
authors.lastname: Wilkinson
authors.forename: James D
authors.initials: JD
authors.lastname: Watts
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Hemmer
mesh_terms: D000818:Animals; D001559:Benzhydryl Compounds; D015415:Biomarkers / Q000097:blood; D004390:Chlorpyrifos / Q000633:toxicity; D003530:Cyprinidae / Q000097:blood*; D004305:Dose-Response Relationship, Drug; D004527:Egg Proteins / Q000097:blood; D004726:Endosulfan / Q000633:toxicity; D004784:Environmental Monitoring / Q000379:methods; D004958:Estradiol / Q000633:toxicity; D004967:Estrogens / Q000633:toxicity*; D005260:Female; D029941:Fish Proteins / Q000097:blood*; D008297:Male; D008731:Methoxychlor / Q000633:toxicity; D010636:Phenols / Q000633:toxicity; D040081:Protein Array Analysis; D040901:Proteomics / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013329:Structure-Activity Relationship; D014874:Water Pollutants, Chemical / Q000633:toxicity*; D000098826:Bisphenol A Compounds
chemical_list: D001559:Benzhydryl Compounds; D015415:Biomarkers; D004390:Chlorpyrifos; D004527:Egg Proteins; D004726:Endosulfan; D004958:Estradiol; D004967:Estrogens; D029941:Fish Proteins; D008731:Methoxychlor; D010636:Phenols; D014874:Water Pollutants, Chemical; C423083:zona radiata protein, fish; C006780:bisphenol A; D000098826:Bisphenol A Compounds