Seasonal variation in equine follicular fluid proteome

Authors: DUTRA, GABRIEL - Southern Illinois University; ISHAK, GHASSAN - Southern Illinois University; PECHAN, PECHANOVA - Mississippi State University; PECHAN, T - Mississippi State University; PETERSON, DANIEL - Mississippi State University; JACOBS, J.C. - Brazilian Center For Physics Research; WILLARD, SCOTT - Mississippi State University; RYAN, PETER - Mississippi State University; GASTAL, EDUARDO - Southern Illinois University; FEUGANG, JEAN - Mississippi State University

Submitted to: Reproductive Biology and Endocrinology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/26/2019
Publication Date: 3/6/2019
Citation: Dutra, G., Ishak, G., Pechan, P., Pechan, T., Peterson, D., Jacobs, J., Willard, S., Ryan, P., Gastal, E., Feugang, J. 2019. Seasonal variation in equine follicular fluid proteome. Reproductive Biology and Endocrinology. 17(1):29. https://doi.org/10.1186/s12958-019-0473-z.
DOI: https://doi.org/10.1186/s12958-019-0473-z

Interpretive Summary: Improvement of female fertility remains a challenge. Numerous proteins of the immediate environment of the female gamete (oocyte) are expected to play important roles on their developmental competence, and may become candiadte markers for their fertility prognosis. The available tools of proteomic permitting the investigation of these proteins have been applied for the investigation of follicular fluid (FF) for several species, and may be important for the study of the seasonal influence on FF proteome that remains unexplored in livestock. Horses are seasonal breeders that could be easily used for the application of high-throughput proteomics of FF to identify seasonal variations of proteins involved in follicle and oocyte growth. Here we (i) profiled the proteomes of equine FF collected from dominant growing follicles during the spring anovulatory season (SAN), and spring (SOV), summer (SUM), and fall (FOV) ovulatory seasons; and (ii) identified season-dependent regulatory networks and associated key proteins. We found that the balance between the FF contents in prothrombin, plasminogen, and coagulation factor XII proteins favoring FF fluidity may be crucial at the peak of the ovulatory season (SUM) and may explain the reported lower incidence of hemorrhagic anovulatory follicles during the SUM season.

Technical Abstract: Total of seventeen Quarter horse mares of 8 to 14 years old, weighing 400 to 600 kg were used. FF samples were collected using transvaginal ultrasound-guided follicle aspiration. Clean FF were subjected to proteome analysis through a shot-gun approach, followed by bioinformatic analyses. Regardless of season, a total of 90 proteins were identified in FF, corresponding to 63, 72, 69, and 78 proteins detected in the SAN, SOV, SUM, and FOV seasons, respectively. Fifty-two proteins were common to all seasons, a total of 13 were unique to either season, and 25 were shared between two seasons or more. Protein-to-protein interaction (PPI) analysis indicated the likely critical roles of plasminogen in the SAN season, the prothrombin/plasminogen combination in SUM, and plasminogen/complement C3 in both SOV and FOV seasons. The apolipoprotein A1 appeared crucial in all seasons. The present findings show that FF proteome of SUM differs from other seasons, with FF having high fluidity (low viscosity).