Reducing CYP51 inhibits follicle-stimulating hormone induced resumption of mouse oocyte meiosis in vitro.
Meiosis activating sterol, produced directly by lanosterol 14-alpha-demethylase (CYP51) during cholesterol biosynthesis, has been shown to promote the initiation of oocyte meiosis. However, the physiological significance of CYP51 action on oocyte meiosis in response to gonadotrophins' induction remained to be further explored. Herein, we analyzed the role of CYP51 in gonadotrophin-induced in vitro oocyte maturation via RNA interference (RNAi). We showed that although both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) significantly induced meiotic resumption in follicle-enclosed oocytes (FEOs), the effect of LH on oocyte meiosis resumption in FEOs was weaker than FSH. Moreover, both FSH and LH were able to upregulate CYP51 expression in cultured follicular granulosa cells when examined at 8 h or 12 h posttreatments, respectively. Interestingly, whereas knockdown of CYP51 expression via small interference RNA (siRNA) moderately blocked (23% reduction at 24 h) FSH-induced oocyte maturation [43% germinal vesicle breakdown (GVBD) rate in RNAi vs. 66% in control, P < 0.05] in FEOs, similar treatments showed no apparent effects on LH-induced FEO meiotic maturation (58% GVBD rate in RNAi vs. 63% in control, P > 0.05). Moreover, the results in a cumulus-enclosed oocytes (CEOs) model showed that approximately 30% of FSH-induced CEOs' meiotic resumption was blocked upon CYP51 knockdown by siRNAs. These findings suggest that FSH, partially at least, employs CYP51, and therefore the MAS pathway, to initiate oocyte meiosis.
School of Basic Medical Sciences, Capital Medical University, Beijing 100069, PR China.
Chao
C
Wang
Baoshan
B
Xu
Bo
B
Zhou
Cheng
C
Zhang
Jie
J
Yang
Hong
H
Ouyang
Gang
G
Ning
Meijia
M
Zhang
Jianzhong
J
Shen
Guoliang
G
Xia
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D054885:Cumulus Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D007986:Luteinizing Hormone / Q000494:pharmacology; D008540:Meiosis / Q000187:drug effects*; D051379:Mice; D008856:Microscopy, Fluorescence; D009865:Oocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D058886:Sterol 14-Demethylase; D013997:Time Factors; D014162:Transfection
D034741:RNA, Small Interfering; D049452:Green Fluorescent Proteins; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D003577:Cytochrome P-450 Enzyme System; C548415:Cyp51 protein, mouse; D058886:Sterol 14-Demethylase