Integrin Regulation of Mammary Gland Development

项目摘要 乳腺上皮由不同的细胞群组成，这些细胞群负责调节乳腺癌的关键基因。 乳腺发育的过程，尤其是泌乳。肺泡祖细胞（AP）部分 分化的干细胞产生肺泡/产奶细胞，这些细胞最近被牵连 作为乳腺癌的起源细胞。通过分析已发表的单细胞RNA-seq数据，整合素β4，一种蛋白质， 已知主要在基底乳腺上皮细胞中起作用，以维持腺体的结构完整性， 发现在AP人群中表达。这个意想不到的结果表明，β4在细胞凋亡中起着新的作用。 AP人群，并可能调节发育中的乳腺内的动态过程。这个目标 我们的建议是了解β4在未经产和哺乳期乳腺AP细胞中的功能作用 并阐明β4调节这一群体的机制。初步研究表明，β4 表达是促进AP细胞祖细胞潜能所必需的，并鉴定了LacdiNAc，一种新的 我们假设β4上的糖基化修饰对于其在脂筏中的定位至关重要， 它在AP人群中的作用。使用AP细胞培养模型以及Cre-lox小鼠模型来条件性地 从AP群体中敲除β4后，将在体外和体外环境中评估β4在AP群体中的功能。 处女和哺乳期乳腺。此外，糖组学分析和生物化学方法将确定新的 研究表明，LacdiNAc对β4聚糖的影响，有助于了解LacdiNAc如何影响AP人群中β4的功能。这 这种方法将进一步加深我们对β4在AP人群中的新作用和新机制的理解 涉及LacdiNAc-β4定位于脂筏以调节肺泡分化。这些研究必须 有可能确定在正常乳腺组织中调节AP群体的新机制 发展以及乳腺癌的进展。

PROJECT SUMMARY The mammary epithelium is composed of diverse cell populations that are responsible for regulating key processes in mammary gland development, especially lactation. Alveolar progenitor (AP) cells are partially differentiated stem cells that produce alveolar/milk-producing cells and these cells have recently been implicated as cells of origin in breast cancer. Through analysis of published single cell RNA-seq data, integrin β4, a protein known to function primarily in basal mammary epithelial cells to maintain structural integrity of the gland, was found to be expressed in the AP population. This unexpected result suggests that β4 plays a novel role in the AP population and may regulate dynamic processes within the developing mammary gland. This goal of this proposal is to understand the functional role of β4 in the AP cells of the nulliparous and lactating mammary gland and elucidate the mechanism by which β4 regulates this population. Preliminary studies have revealed that β4 expression is necessary to promote progenitor potential of the AP cells and identified LacdiNAc, a novel glycosylation modification, on β4 that we hypothesize is essential for its localization in lipid rafts that promotes its function in the AP population. Using an AP cell culture model as well as a Cre-lox mouse model to conditionally knock out β4 from the AP population, the function of β4 in the AP population will be assessed in vitro and in the virgin and lactating mammary gland. Also, glycomics analyses and biochemical approaches will identify novel glycans on β4 and help in understanding how LacdiNAc affects function of β4 in the AP population. This approach will further our understanding of the novel role of β4 in the AP population and a new mechanism involving LacdiNAc-β4 localization to lipid rafts to regulate alveolar differentiation. These studies have to potential to define novel mechanisms that regulate the AP population during normal mammary gland development as well as breast cancer progression.