Location: Livestock Bio-SystemsTitle: iTRAQ-based proteomic analysis of bovine pre-ovulatory plasma and follicular fluid
|AFEDI, PATIENCE - South Dakota State University|
|LARIMORE, ERIN - South Dakota State University|
|Cushman, Robert - Bob|
|RAYNIE, DOUGLAS - South Dakota State University|
|PERRY, GEORGE - South Dakota State University|
Submitted to: Domestic Animal Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/16/2021
Publication Date: 7/1/2021
Publication URL: https://handle.nal.usda.gov/10113/7301068
Citation: Afedi, P.A., Larimore, E.L., Cushman, R.A., Raynie, D., Perry, G.A. 2021. iTRAQ-based proteomic analysis of bovine pre-ovulatory plasma and follicular fluid. Domestic Animal Endocrinology. 76:106606. https://doi.org/10.1016/j.domaniend.2021.106606.
Interpretive Summary: Cows that express behavioral estrus during a timed artificial insemination protocol are more fertile. Studies applying ultrasonography have indicated that this is because the follicle grows faster and releases the egg earlier when cows express estrus. Proteomic analysis of the follicular fluid was applied to verify differences in the mechanisms contributing to rupture of the follicle and release of the egg between cows that express estrus and cows that do not express estrus. Abundance of proteins directly involved in rupture of the follicle was greater in the follicular fluid of cows that expressed estrus than cows that did not express estrus. These results support the theory that timing between maturation of the egg and arrival of the sperm is disrupted in cows that do not express estrus, leading to decreased fertility.
Technical Abstract: Bovine follicular fluid (FF) creates a unique microenvironment in follicles necessary for follicle growth, oocyte maturation, and estradiol (E2) production. The objective of this study was to analyze changes in proteins in FF and plasma (PL) from animals with high E2 (HE2) or low E2 (LE2) during the pre-ovulatory period. Beef cows were synchronized, and follicular dynamics and ovulatory response were monitored using transrectal ultrasonography. Nine cows were selected and slaughtered, blood samples were collected at slaughter and FF was aspirated from dominant follicles (DF; >10 mm). Abundant proteins (albumin, IgG, IgA, and alpha-1-antitrypsin) were depleted from both PL and FF. Peptides were labeled with iTRAQ reagents and quantified using 2-dimentional liquid chromatography ESI-based mass spectrometry. Estradiol was associated with protein changes in PL and FF. Protein expression changes between FF HE2 and FF LE2 were greater than between PL HE2 and PL LE2. There were 15 up-regulated proteins and 10 down-regulated proteins in FF HE2 compared to FF LE2, and 7 proteins up-regulated and 9 proteins down-regulated in PL HE2 compared to PL LE2. Several of the differentially expressed proteins function in follicle development and were mainly categorized under cellular process and metabolic process. Pathway analysis identified the up- and down-regulated proteins were predominantly associated with the complement and coagulation cascades. The data demonstrate E2 regulates a wide range of reproductive associated proteins in bovine PL and FF and can provide the basis for further investigation of specific processes involved in such regulation.