EPIGENOMIC RELATIONSHIP TO A SEX DIFFERENCE IN HYPOTHALAMIC LHRH MRNA EXPRESSION

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 目的：研究LHRH基因表达是否存在性别差异以及其他已知影响LHRH神经元活性的神经系统。 促黄体生成激素释放激素（LHRH）是生殖功能的关键调节因子。成年恒河猴（macacamulatta）下丘脑中LHRH基因的表达受性腺类固醇激素的调节，雌性主要是雌激素，雄性主要是雄激素。 尽管存在这种差异，但没有关于性别特异性信号如何调节LHRH基因表达的报道。 从性腺完整的成年雄性（n=5，11.0 <$1.7岁）和雌性（n=5，11.2 <$2.0岁）恒河猴的内侧基底下丘脑（MBH）和视前区（POA）收集RNA和DNA。雌性猴的排卵周期时相未知，因为它们是从组织分布程序中获得的。采用定量PCR，我们发现男性MBH中LHRH mRNA水平显著低于女性（p0.05），但POA中无差异。此外，我们还发现，GAD 65，GAD 67，NPY，KiSS-1和GPR 54 mRNA在两个区域中没有性别差异。因为灵长类动物下丘脑LHRH神经分泌系统中没有永久性的性别分化，即，在切除卵巢的成年雄性猴中，通过卵巢移植可以诱导LH激增（Norman和Spies Endocrinology 118：2608-2610，1986），可能是表观遗传机制调节LHRH基因表达的性别差异。在第二个实验中，我们研究了CpG甲基化，一种影响转录因子结合和基因表达的DNA共价修饰，是否在性别之间存在差异。初步研究显示，在LHRH基因的5'侧翼区域，男性表现出比女性更高的CpG甲基化趋势（p <0.1）。这种甲基化位于相对于恒河猴LHRH基因转录起始位点的CpG富集区-2100/-1700。总的来说，这些结果表明，有一个显着的性别差异，在恒河猴LHRH mRNA水平，这可能与CpG甲基化的差异。它的结论是，表观基因组修饰的因素在复杂的编排LHRH基因在灵长类动物中的表达。 本研究使用WNPRC Animal Services（病理学服务）。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Objective: To investigate whether sex differences exist in gene expression of LHRH as well as other neuronal systems known to influence LHRH neuronal activity. Luteinizing-hormone releasing hormone (LHRH) is a key regulator of reproductive function. Adult rhesus monkey (macaca mulatta) LHRH gene expression in the hypothalamus is regulated by gonadal steroids, primarily estrogens in females and androgens in males. Despite this distinction, there is no report of how sex-specific signals regulate LHRH gene expression. RNA and DNA were collected from the medial basal hypothalamus (MBH) and preoptic area (POA) of gonadally intact adult male (n=5, 11.0¿1.7 years of age) and female (n=5, 11.2¿2.0 years of age) rhesus monkeys. The phases of ovulatory cycle in the female monkeys were unknown, as they were obtained from the tissue distribution program. Using quantitative PCR, we found that LHRH mRNA levels in the MBH are significantly lower in males compared to females (p0.05), but there was no difference in the POA. Moreover, we found that there were no sex differences in GAD65, GAD67, NPY, KiSS-1, and GPR54 mRNA in either area. Because there is no permanent sexual differentiation in the primate hypothalamic LHRH neurosecretory system, i.e., LH surges could be induced by ovarian transplantation in orchidectomized adult male monkeys (Norman and Spies Endocrinology 118:2608-2610, 1986), it is possible that an epigenetic mechanism regulates the sex difference in LHRH gene expression. In the second experiment we investigated if CpG methylation, a covalent modification of DNA that influences transcription factor binding and gene expression, was different between the sexes. Preliminary investigations revealed a trend (p0.1) with males exhibiting higher CpG methylation than females in the 5' flanking region of the LHRH gene. This methylation is in a CpG rich region -2100/-1700 relative to the transcription start site in the rhesus LHRH gene. Collectively, these results indicate that there is a significant sex difference in LHRH mRNA levels in rhesus monkeys and that this may be related to a difference in CpG methylation. It is concluded that epigenomic modifications are factors in the complex orchestration of LHRH gene expression in primates. This research used WNPRC Animal Services (Pathology Services).