ROLE OF MIR146B IN SURVIVAL & SELF RENEWAL OF MAMMARY ALVEOLAR PROGENITOR CELLS

这个子项目是许多利用资源的研究子项目之一 由NIH/NCRR资助的中心拨款提供。子项目的主要支持 而子项目的主要调查员可能是由其他来源提供的， 包括其它NIH来源。 列出的子项目总成本可能 代表子项目使用的中心基础设施的估计数量， 而不是由NCRR赠款提供给子项目或子项目工作人员的直接资金。 microRNA（miRNAs）是一类内源性、非编码、单链分子， 基因表达的转录后调节因子。传统上，miRNA在转录后的功能 基因沉默据估计，30-60%的基因组由miRNA介导的沉默调节，但最近的研究表明， 研究描述了miRNA还可以介导mRNA翻译的上调。先前的研究 miRNAs参与了广泛的生物学功能，并在各种疾病中发挥重要作用。 包括癌症在内的人类疾病。虽然已经鉴定了对大多数体干细胞重要的miRNA， miRNAs在正常乳腺干细胞和祖细胞中所起作用还没有被完全阐明 研究了最近，已经报道miR 146 b参与抑制癌细胞迁移， 侵袭和抑制乳腺癌转移。然而，miR 146 b在细胞内的生理作用是不确定的。 正常的乳腺发育尚未确定。本申请的目的是 发现miR 146 b在乳腺肺泡祖细胞存活和自我更新中的作用， 鉴定其下游分子靶点。我们的中心假设是miR 146 b促进肺泡 通过激活Stat-5和抑制Stat-3，在妊娠期间祖细胞存活和自我更新。 Stat-5在妊娠期肺泡细胞存活和自我更新中起重要作用，而Stat-3在妊娠期肺泡细胞存活和自我更新中起重要作用。 在退化过程中乳腺腺泡死亡中起重要作用。我们将通过以下方式实现这些实验目标： 具体目标1：证明miR 146 b促进存活和自我更新 在乳腺腺泡祖细胞中，这将通过体外操纵 miR 146 b在源自乳腺上皮细胞系的多能、导管和肺泡祖细胞中的表达， 在来自雌性Balb/C处女和妊娠小鼠的肺泡祖细胞中。具体目标2：阐明 miR 146 b在抑制Stat-3和激活Stat-5中的作用。荧光素酶报告基因和CHIP测定将 用于证实miR 146 b对这两个基因的调控。我们研究的长期目标是阐明 microRNA在乳腺干细胞和祖细胞存活和自我更新中的作用。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. MicroRNAs (miRNAs) are a class of endogenous, non-coding, single-stranded molecules which are crucial post-transcriptional regulators of gene expression. Traditionally the miRNA function in post-transcriptional gene silencing. An estimated 30-60% of the genome is regulated by miRNA-mediated silencing, but recent studies described that miRNA can also mediate upregulation of mRNA translation. Previous studies have shown that miRNAs participate in a wide range of biological functions and play important roles in various human diseases including cancer. While miRNAs important to most somatic stem cells have been identified, the role that miRNAs play in normal mammary gland stem and progenitor cells has yet to be fully investigated. Recently, miR146b has been reported to be involved in inhibition of cancer cell migration and invasion, and suppression of breast cancer metastasis. However, the physiological role of miR146b in normal mammary gland development has not been determined. The objective of this application is to discover the role of miR146b in the survival and self-renewal of mammary alveolar progenitor cells and identify its downstream molecular targets. Our central hypothesis is that miR146b facilitates alveolar progenitor survival and self-renewal during pregnancy through activation of Stat-5 and inhibition of Stat-3. Stat-5 plays an essential role in alveolar cell survival and self-renewal during pregnancy and Stat-3 plays a crucial role in mammary alveolar death during involution. We will achieve these experimental goals through the following specific aims: Specific aim 1: To demonstrate that miR146b promotes survival and self-renewal in mammary alveolar progenitor cells, this will be achieved by in vitro manipulation of the expression of miR146b in multipotent, ductal and alveolar progenitor cells derived from a mammary epithelial cell line and in alveolar progenitor cells derived from female Balb/C virgin and pregnant mice. Specific aim 2: Elucidate the role of miR146b in suppressing Stat-3 and activation of Stat-5. Luciferase reporter and CHIP assays will be used to confirm miR146b regulation of these two genes.The long-term goal of our research is to elucidate the role of microRNAs in mammary gland stem and progenitor cell survival and self-renewal.