MUCOUS CELL DIFFERENTIATION IN AIRWAY EPITHELIUM

粘液纤毛功能是抵御各种疾病的第一种防御机制 吸入性污染物在传导呼吸道上皮中。维生素A是一种 参与调控这些功能的最重要因素。 已经进行了许多研究，但维生素A调节的性质 在这些不同的功能中，很大程度上仍不清楚。研究对象： 这笔赠款(RO1-HL35635)的支持表明，上皮细胞 来自人类、猴子和仓鼠的气管、支气管组织的细胞能够 在培养中表达粘液细胞分化，分化为 依赖于维生素A的存在，没有维生素A，上皮细胞 在培养中表达鳞状细胞分化。这是一次竞争性更新 应用涉及粘液细胞分化的生物学。 基于对显微注射和基因克隆的初步研究， 我们假设维生素A在两种情况下调节粘液细胞分化 不同的阶段。第一阶段是一个胜任阶段，在这个阶段，鳞片 上皮细胞与鳞状细胞或粘液细胞脱节 维生素A治疗后的分化。第二阶段涉及 作为一个进行性阶段，未被承诺的细胞致力于粘液 维生素A处理后细胞分化。我们还假设 每个阶段都涉及到不同的新基因表达。它是 建议研究这两个阶段的基因表达，并 明确这些新基因在粘液细胞调节中的作用 差异化。我们的具体目标是：1)克隆和表征 维生素A反应基因，重点关注与早期相关的基因 事件和差异，2)定义水平(即转录， 翻译)受维生素A调控的基因表达，3)确定 这些基因对粘液细胞是否必要和充分 分化，4)确定前体-粘液细胞的关系和 细胞类型特异性基因在两相器官培养中的表达 系统。已分离到几个维生素A反应的cDNA克隆，并 它们最初将被用于定义粘液细胞的阶段 并阐明维生素A的调节机制。

Mucociliary functions are the first defense mechanism against various inhaled pollutants in conducting airway epithelium. Vitamin A is one of the most important factors involved in the regulation of these functions. Many studies have been carried out, but the nature of vitamin A regulation in these differentiated functions is still largely unclear. Studies with support from this grant (RO1-HL35635) have demonstrated that epithelial cells from human, monkey, and hamster tracheobronchial tissues are able to express mucous cell differentiation in culture and the differentiation is dependent on the presence of vitamin A. Without vitamin A, epithelial cells express squamous cell differentiation in culture. This competitive renewal application is concerned with the biology of mucous cell differentiation. Based on preliminary studies with the microinjection and genetic cloning, we hypothesize that vitamin A regulates mucous cell differentiation in two different stages. The first stage is a competent phase in which squamous epithelial cells become uncommitted to squamous or mucous cell differentiation after the vitamin A treatment. The second stage regards as a progressive phase in which uncommitted cells are committed to mucous cell differentiation after the vitamin A treatment. We also hypothesize that each stage involves different sets of new gene expression. It is proposed to investigate the gene expression in these two stages and to define the roles of these new genes in the regulation of mucous cell differentiation. Our specific aims are: 1) to clone and to characterize vitamin A-responsive genes with a focus on those involved in the early events and differentiation, 2) to define the level (i.e. transcription, translation) of gene expression regulated by vitamin A, 3) to determine whether these genes are necessary and sufficient for mucous cell differentiation, 4) to determine precursor-mucous cells relationship and cell type-specific gene expression in a biphasic organotypic culture system. Several vitamin A-responsive cDNA clones have been isolated and they will be used initially to define the stage of mucous cell differentiation and to elucidate the mechanism of vitamin A regulation.