Role of Dicer in Gonadotrope and Reproductive Function

性状（由申请人提供）：促性腺激素合成并分泌异二聚体糖蛋白促黄体生成素（LH）和促卵泡激素（FSH），这两种糖蛋白对 生殖功能编码共同α亚基（Cga）和前列腺特异性β亚基（Lhb和Fshb）的基因受下丘脑促性腺激素释放激素、类固醇和性腺肽、促性腺激素和激活素的协调调节。虽然对促性腺激素β亚基的转录调控已经积累了丰富的知识，但这些基因的转录后机制尚不清楚。最近，由RNA内切酶III Dicer产生的微小RNA（miRNAs）已经成为基因表达、mRNA稳定性和蛋白质合成的关键调节因子。对调节促性腺激素并因此调节生殖功能的miRNAs的知识缺乏。我们的长期研究目标是阐明体内调节促性腺激素合成和分泌的机制。核心假设是Dicer是促性腺激素细胞中miRNA生物合成的关键因子，在促性腺激素合成和生殖功能中起重要作用。在具体目标1中，我们将通过cre-lox技术有条件地删除促性腺激素细胞中的Dicer，并分析促性腺激素的合成和分泌。此外，我们将使用新的小鼠品系，其中促性腺激素在正常或激活素受体-II（Acvr 2）空遗传背景上用GFP标记。通过基于GFP荧光的细胞分选从这些小鼠中分离纯的促性腺激素群体，并鉴定由Acvr 2调节的miRNA。在具体目标2中，将确定促性腺激素中Dicer缺失导致的促性腺激素变化继发的生殖表型。这些研究将为促性腺激素细胞中Dicer依赖性miRNAs提供新的知识，并确定促性腺激素分泌的新的转录后机制。促性腺激素分泌机制的描述是生殖生理学的基础，并为诊断和治疗促性腺激素依赖性生育/不育疾病提供了长期的临床益处。 公共卫生相关性：我们的研究将为Dicer如何调节垂体促卵泡激素（FSH）和促黄体激素（LH）的合成和分泌提供新的知识。FSH和LH分泌机制的描述是生殖生理学的基础，并为诊断和治疗FSH依赖性生育/不育疾病提供了临床益处。其中包括过度刺激综合征、闭经和睾丸缺陷。

DESCRIPTION (provided by applicant): Gonadotropes synthesize and secrete heterodimeric glycoproteins luteinizing hormone (LH) and follicle stimulating hormone (FSH) that are critical for reproductive function. The genes encoding the common alpha subunit (Cga) and the hormone-specific beta subunits (Lhb and Fshb) are coordinately regulated by hypothalamic gonadotropin-releasing hormone, steroids and gonadal peptides, inhibin and activin. Although a wealth of knowledge has accumulated on transcriptional control of gonadotropin beta subunits, post- transcriptional mechanisms of these genes are unknown. Recently, micro RNAs (miRNAs) produced by Dicer, an RNA endonuclease III, have emerged as key regulators of gene expression, mRNA stability and protein synthesis. Knowledge on miRNAs that regulate gonadotrope and consequently reproductive function is lacking. Our long-term research goal is to elucidate the in vivo mechanisms that regulate gonadotropin synthesis and secretion. The central hypothesis is that Dicer is a key factor in miRNA biogenesis in gonadotropes and plays essential roles in gonadotropin synthesis and consequently reproductive function. In Specific Aim 1, we will conditionally delete Dicer exclusively in gonadotropes by cre-lox technology and analyze gonadotropin synthesis and secretion. Additionally, we will use novel mouse strains, in which gonadotropes are labeled with GFP on a normal or activin receptor-II (Acvr2) null genetic background. Pure populations of gonadotropes will be isolated from these mice by cell sorting based on GFP fluorescence and miRNAs regulated by Acvr2 identified. In Specific Aim 2, reproductive phenotypes secondary to changes in gonadotropins as a result of Dicer deletion in gonadotropes will be determined. These studies should provide new knowledge on Dicer - dependent miRNAs in gonadotropes and identify novel post-transcriptional mechanisms for gonadotropin secretion. Delineation of mechanisms of gonadotropin secretion is fundamental to physiology of reproduction and offers long-term clinical benefits of diagnosing and treating gonadotropin-dependent fertility/infertility disorders. PUBLIC HEALTH RELEVANCE: Our studies should provide new knowledge on how Dicer that produces small RNAs called micro RNAs regulates synthesis and secretion of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from pituitary gland. Delineation of mechanisms of FSH and LH secretion is fundamental to physiology of reproduction and offers clinical benefits of diagnosing and treating FSH-dependent fertility/infertility disorders. Some of these include hyperstimulation syndromes, amenorrhea and testicular defects.