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Altered theca and cumulus oocyte complex gene expression, follicular arrest and reduced fertility in cows with dominant follicle follicular fluid androgen excess.

Summers AF, Pohlmeier WE, Sargent KM, Cole BD, Vinton RJ, Kurz SG, McFee RM, Cushman RA, Cupp AS, Wood JR - PLoS ONE (2014)

Bottom Line: We hypothesized that the steroid excess in follicular fluid of dominant follicles in High A4 cows would result in reduced fertility through altered follicle development and oocyte maternal RNA abundance.There was a tendency for reduction in stage 4 follicles in ovarian cortex samples from High A4 cows suggesting that progression to antral stages were impaired.These data suggest that the dominant follicle environment of High A4 cows including reduced estrogen conversion and androgen excess contributes to infertility in part through altered follicular and oocyte development.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.

ABSTRACT
Aspiration of bovine follicles 12-36 hours after induced corpus luteum lysis serendipitously identified two populations of cows, one with High androstenedione (A4; >40 ng/ml; mean = 102) and another with Low A4 (<20 ng/ml; mean = 9) in follicular fluid. We hypothesized that the steroid excess in follicular fluid of dominant follicles in High A4 cows would result in reduced fertility through altered follicle development and oocyte maternal RNA abundance. To test this hypothesis, estrous cycles of cows were synchronized and ovariectomy was performed 36 hours later. HPLC MS/MS analysis of follicular fluid showed increased dehydroepiandrosterone (6-fold), A4 (158-fold) and testosterone (31-fold) in the dominant follicle of High A4 cows. However, estrone (3-fold) and estradiol (2-fold) concentrations were only slightly elevated, suggesting a possible inefficiency in androgen to estrogen conversion in High A4 cows. Theca cell mRNA expression of LHCGR, GATA6, CYP11A1, and CYP17A1 was greater in High A4 cows. Furthermore, abundance of ZAR1 was decreased 10-fold in cumulus oocyte complexes from High A4 cows, whereas NLRP5 abundance tended to be 19.8-fold greater (P = 0.07). There was a tendency for reduction in stage 4 follicles in ovarian cortex samples from High A4 cows suggesting that progression to antral stages were impaired. High A4 cows tended (P<0.07) to have a 17% reduction in calving rate compared with Low A4 cows suggesting reduced fertility in the High A4 population. These data suggest that the dominant follicle environment of High A4 cows including reduced estrogen conversion and androgen excess contributes to infertility in part through altered follicular and oocyte development.

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Maternal Effect Gene ZAR1 mRNA Abundance is Reduced in High A4 Compared with Low A4 Cows.Quantitative RT-PCR results for ZAR1 (A), NLRP5 (B), DPPA3 (C), and DNMT1 (D); in cumulus oocyte complexes of High A4 (black bars, n≥3) and Low A4 (white bars, n≥5) cows. The geometric mean of GAPDH and RPL-15 was used as an endogenous control. Graphs represent a fold change in mRNA abundance with Low A4 set as control (1). Data for NLRP5 and DPPA3 were log transformed to meet normal distribution assumptions. The mean ± SEM normalized values are presented. *, P≤0.05.
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pone-0110683-g005: Maternal Effect Gene ZAR1 mRNA Abundance is Reduced in High A4 Compared with Low A4 Cows.Quantitative RT-PCR results for ZAR1 (A), NLRP5 (B), DPPA3 (C), and DNMT1 (D); in cumulus oocyte complexes of High A4 (black bars, n≥3) and Low A4 (white bars, n≥5) cows. The geometric mean of GAPDH and RPL-15 was used as an endogenous control. Graphs represent a fold change in mRNA abundance with Low A4 set as control (1). Data for NLRP5 and DPPA3 were log transformed to meet normal distribution assumptions. The mean ± SEM normalized values are presented. *, P≤0.05.

Mentions: To determine the effect of altered follicular fluid concentrations of steroid hormones on the molecular phenotype of the cumulus-oocyte complex, QPCR analyses of candidate genes were carried out. The abundance of two maternal effect genes was differentially expressed in COCs of High vs. Low A4 cows. Specifically, ZAR1 mRNA was reduced 10-fold in High A4 (P = 0.04, Fig. 5A) compared with Low A4 cows. Likewise, NLRP5 gene expression tended to be increased 19.8-fold in High A4 cows (P = 0.07, Fig. 5B). However, there was no difference in DNMT1 (P = 0.12, Fig. 5C) or DPPA3 (Fig. 5D, P = 0.94) mRNA abundance between High and Low A4 cows. Despite these differences in maternal effect gene transcripts, the mRNA levels of miRNA processing genes in the COCs were not different between the two cow populations. Specifically, there was no difference in expression of (DiGeorge syndrome critical region 8 (DGCR8), RNASEN, exportin 5 (XPO5), DICER, or EIF2C2 (Fig. S2) based on A4 classification.


Altered theca and cumulus oocyte complex gene expression, follicular arrest and reduced fertility in cows with dominant follicle follicular fluid androgen excess.

Summers AF, Pohlmeier WE, Sargent KM, Cole BD, Vinton RJ, Kurz SG, McFee RM, Cushman RA, Cupp AS, Wood JR - PLoS ONE (2014)

Maternal Effect Gene ZAR1 mRNA Abundance is Reduced in High A4 Compared with Low A4 Cows.Quantitative RT-PCR results for ZAR1 (A), NLRP5 (B), DPPA3 (C), and DNMT1 (D); in cumulus oocyte complexes of High A4 (black bars, n≥3) and Low A4 (white bars, n≥5) cows. The geometric mean of GAPDH and RPL-15 was used as an endogenous control. Graphs represent a fold change in mRNA abundance with Low A4 set as control (1). Data for NLRP5 and DPPA3 were log transformed to meet normal distribution assumptions. The mean ± SEM normalized values are presented. *, P≤0.05.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4199720&req=5

pone-0110683-g005: Maternal Effect Gene ZAR1 mRNA Abundance is Reduced in High A4 Compared with Low A4 Cows.Quantitative RT-PCR results for ZAR1 (A), NLRP5 (B), DPPA3 (C), and DNMT1 (D); in cumulus oocyte complexes of High A4 (black bars, n≥3) and Low A4 (white bars, n≥5) cows. The geometric mean of GAPDH and RPL-15 was used as an endogenous control. Graphs represent a fold change in mRNA abundance with Low A4 set as control (1). Data for NLRP5 and DPPA3 were log transformed to meet normal distribution assumptions. The mean ± SEM normalized values are presented. *, P≤0.05.
Mentions: To determine the effect of altered follicular fluid concentrations of steroid hormones on the molecular phenotype of the cumulus-oocyte complex, QPCR analyses of candidate genes were carried out. The abundance of two maternal effect genes was differentially expressed in COCs of High vs. Low A4 cows. Specifically, ZAR1 mRNA was reduced 10-fold in High A4 (P = 0.04, Fig. 5A) compared with Low A4 cows. Likewise, NLRP5 gene expression tended to be increased 19.8-fold in High A4 cows (P = 0.07, Fig. 5B). However, there was no difference in DNMT1 (P = 0.12, Fig. 5C) or DPPA3 (Fig. 5D, P = 0.94) mRNA abundance between High and Low A4 cows. Despite these differences in maternal effect gene transcripts, the mRNA levels of miRNA processing genes in the COCs were not different between the two cow populations. Specifically, there was no difference in expression of (DiGeorge syndrome critical region 8 (DGCR8), RNASEN, exportin 5 (XPO5), DICER, or EIF2C2 (Fig. S2) based on A4 classification.

Bottom Line: We hypothesized that the steroid excess in follicular fluid of dominant follicles in High A4 cows would result in reduced fertility through altered follicle development and oocyte maternal RNA abundance.There was a tendency for reduction in stage 4 follicles in ovarian cortex samples from High A4 cows suggesting that progression to antral stages were impaired.These data suggest that the dominant follicle environment of High A4 cows including reduced estrogen conversion and androgen excess contributes to infertility in part through altered follicular and oocyte development.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Science, University of Nebraska-Lincoln, Lincoln, Nebraska, United States of America.

ABSTRACT
Aspiration of bovine follicles 12-36 hours after induced corpus luteum lysis serendipitously identified two populations of cows, one with High androstenedione (A4; >40 ng/ml; mean = 102) and another with Low A4 (<20 ng/ml; mean = 9) in follicular fluid. We hypothesized that the steroid excess in follicular fluid of dominant follicles in High A4 cows would result in reduced fertility through altered follicle development and oocyte maternal RNA abundance. To test this hypothesis, estrous cycles of cows were synchronized and ovariectomy was performed 36 hours later. HPLC MS/MS analysis of follicular fluid showed increased dehydroepiandrosterone (6-fold), A4 (158-fold) and testosterone (31-fold) in the dominant follicle of High A4 cows. However, estrone (3-fold) and estradiol (2-fold) concentrations were only slightly elevated, suggesting a possible inefficiency in androgen to estrogen conversion in High A4 cows. Theca cell mRNA expression of LHCGR, GATA6, CYP11A1, and CYP17A1 was greater in High A4 cows. Furthermore, abundance of ZAR1 was decreased 10-fold in cumulus oocyte complexes from High A4 cows, whereas NLRP5 abundance tended to be 19.8-fold greater (P = 0.07). There was a tendency for reduction in stage 4 follicles in ovarian cortex samples from High A4 cows suggesting that progression to antral stages were impaired. High A4 cows tended (P<0.07) to have a 17% reduction in calving rate compared with Low A4 cows suggesting reduced fertility in the High A4 population. These data suggest that the dominant follicle environment of High A4 cows including reduced estrogen conversion and androgen excess contributes to infertility in part through altered follicular and oocyte development.

Show MeSH
Related in: MedlinePlus