Histone Deacetylation 3 Governs Meiotic Progress Of Pre-ovulatory Oocytes In Mammals

Successful female mammalian reproduction requires that oocytes reenter meiosis,ovulate from follicle,and acquire the ability to be fertilized.During the pre-ovulatory period,the gonadotropin luteinizing hormone(LH)terminates granulosa cells growth,promotes somatic cells luteinzation,and induces a large changes in gene expression,leading to the meiosis resumption in oocytes,as well as ovulation.Defects in LH action on ovary follicle result in ovulation compromise and even infertility,such as PCOS and POF.Thus,a better understanding of the mechanism how LH function on cell differentiation is of a paramount important to improve assistant reproduction,as well as to provide novel opportunities for clinical therapy of ovulation failure.In this paper,two-dimensional electrophoresis was applied to investigate the mechanism of LH on oocytes maturation.Histone deacetylase 3(HDAC3)was found to be downregulated markedly by LH.It has been reported that HDAC3 level was apparently higher in the granulosa cells from PCOS patient,and the development potential of oocytes from the PCOS patient was much lower.However,the role of HDAC3 in oocytes maturation was still unidentified.Here,we provide evidence showing that HDAC3 played an essential role in the process of oocytes meiosis in mouse.HDAC3 was decreased by LH obviously in the granulosa cells of ovulation follicles under physiology conditions.Moreover,we found that in the cultured follicles in vitro,HDAC3 specific inhibitor(FHDACi 4b)was able to dramatically induced oocytes maturation compared to control group.A further study showed that AREG mediated HDAC3 action on the oocytes maturation.Using chromatin immunoprecipitation(ChIP)analysis we found that,before LH surge,HDAC3 is able to bind the promoter of the AREG gene directly and inhibit gene expression.Following with LH surge coming,the level of HDAC3 decreased and thus the acetylation of H3K14 increased in the promoter of AREG suggesting that H3K14 acetylation mediated the action of HDAC3.Finally,ChIP assay revealed that the level of SP1 binding to AREG promoter increased markedly when the granulosa cells treated with LH or HDACi 4b,indicating that H3K14 acetylation unfold chromatin and promoted SP1 binding to AREG promoter region.Furthermore,we found that HDACi 4b treating mGC feeders could obviously improve oocyte maturation and blastocyst developmental capacity in vitro,which resulted in higher birth rate compared to the control after the blastocysts transferred in to the surrogate mice.Based on these findings,we further proved that HDAC3 promoted AREG expression via regulating H3K14ac and the binding ability of SP1 in human granulosa cells as well.In this paper,we illuminated the role of histone acetylation in granulosa cells on oocytes maturation following with LH surge.And HDAC inhibitor was identified that it could mimic LH action on promoting oocyte maturation and developmental capacity in vitro,thus suggesting a hopeful therapeutic strategy for diseases of ovulation failure.