Role of MicroRNA-29 in Uterine Leiomyoma Pathogenesis

描述（由申请人提供）：平滑肌瘤是高度普遍的子宫良性肿瘤，在50岁以上的女性中总体患病率为70%。在美国，它们是子宫切除术的主要原因，占每年60万例子宫切除术的近50%，每年的医疗保健费用为340亿美元。尽管它们的患病率和公共卫生影响，调节平滑肌瘤的发展和生长的细胞和分子机制尚不清楚。在表型上，这些肿瘤与邻近的正常组织不同，主要是由于细胞外基质成分，特别是主要的纤维性胶原（I、II和III）的过量产生。我们和其他人已经证明，除了LEIO和MYO之间的差异表达基因外，microrna的表达也存在差异，这表明它们在这些肿瘤的基因调控中发挥作用。MicroRNAs是一类负性调节基因表达的小非编码rna。虽然有几项研究证明了激素和生长因子对mirna在平滑肌瘤中的调节作用，但没有一项研究表明它们在平滑肌瘤的主要区别病理表现：过度胶原沉积方面具有功能作用。我们的实验室发现，与正常子宫肌瘤组织相比，miR-29家族的所有成员（29a, 29b, 29c）在平滑肌瘤中下调。根据最近在其他纤维化疾病中的研究和本申请中包含的初步数据，我们假设miRNA-29家族的这种失调在平滑肌瘤中发现的异常细胞外基质成分中起功能作用。为了解决这一假设，我们提出了以下两个具体目标：在specific Aim 1中，我们试图确定TGF-¿3调节子宫平滑肌瘤中miR-29水平的机制。已知TGF-¿3在平滑肌瘤中的浓度高于邻近的正常子宫肌瘤组织。为了确定其在miRNA-29调控中的作用，我们将进行SMAD2/3敲除和染色质免疫沉淀研究。在Specific Aim 2中，我们将确定miR-29家族（a/b/c）对子宫平滑肌瘤中过量主要纤维胶原生成的贡献。miRNA-29的作用将通过敲低和过表达研究进行评估。这些研究的结果不仅将提供平滑肌瘤中过量细胞外基质的机制信息，而且还将为未来的临床前研究奠定基础，因为我们对人类疾病中的mirna和基于寡核苷酸的治疗方法的理解将继续扩大。

DESCRIPTION (provided by applicant): Leiomyomas are highly pervasive benign tumors of the uterus that have an overall prevalence of 70% in women by the age of 50. They are the leading cause of hysterectomy in the United States, accounting for almost 50% of the 600,000 hysterectomies performed annually and $34 billion dollars in annual healthcare costs. Despite their prevalence and public health impact, the cellular and molecular mechanisms regulating the development and growth of leiomyoma are not well understood. Phenotypically, these tumors are distinct from the adjacent normal tissue largely due to the overproduction of extracellular matrix component, especially the major fibrillar collagens (I, II, and III). We, and others, have demonstrated that in addition to differentially expressed genes between LEIO and MYO, there is differential expression of microRNAs, suggesting that they play a role in gene regulation of these tumors. MicroRNAs are a class of small non-coding RNAs that negatively regulate gene expression. While several studies have documented hormonal and growth factor regulation of miRNAs in leiomyomata, none have demonstrated a functional role for them in terms of their main distinguishing pathological finding: excessive collagen deposition. Our lab has found that all of the members of the miR-29 family (29a, 29b, 29c) are downregulated in leiomyoma versus normal myometrial tissue. Based on recent studies in other fibrotic diseases and preliminary data included in this application, we hypothesize that this dysregulation of the miRNA-29 family plays a functional role in the aberrant extracellular matrix components found in leiomyomata. To address this hypothesis, we propose the following two specific aims: In Specific Aim 1 we seek to determine the mechanism by which TGF-¿3 regulates miR-29 levels in uterine leiomyomas. TGF-¿3 is known to be present in higher concentrations in leiomyoma versus adjacent normal myometrial tissue. To determine its role in the regulation of miRNA-29, we will perform SMAD2/3 knockdown and chromatin immunoprecipitation studies. In Specific Aim 2, we will determine the contribution of the miR-29 family (a/b/c) to the excess major fibrillar collagen production in uterine leiomyoma. The role of miRNA-29 will be assessed using knockdown and overexpression studies. The results from these studies will not only provide mechanistic information on the excess extracellular matrix seen in leiomyomas, but will also lay the foundation for future preclinical studies as our understanding of both miRNAs in human disease and oligonucleotide based therapeutics continues to expand.