GATA-6: Key Regulator of AEC Transdifferentiation

GATA-6：AEC 转分化的关键调节因子

• 批准号: 6830705
• 负责人: Zea Borok
• 金额: $ 36.61万
• 依托单位: UNIVERSITY OF SOUTHERN CALIFORNIA
• 依托单位国家: 美国
• 财政年份: 1986
• 资助国家: 美国
• 起止时间: 1986-09-01 至 2007-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6830705
• 关键词: DNA binding protein; biological fluid transport; cell differentiation; cell growth regulation; cell type; chromatin immunoprecipitation; gel mobility shift assay; gene expression; intermolecular interaction; laboratory rat; lung alveolus; lung injury; phenotype; respiratory epithelium; tissue /cell culture; transcription factor

DESCRIPTION (provided by applicant): It is generally believed that alveolar epithelial type II (AT2) cells serve as progenitors of type I (AT1) cells in development and following injury to restore the alveolar gas exchange surface. However, the transcriptional programs that mediate differentiation between alveolar epithelial cell (AEC) phenotypes are almost entirely unknown. We have developed well-defined primary cell culture systems in which AEC transdifferentiation in vitro can be experimentally modulated, providing an excellent model with which to dissect molecular pathways that regulate transitions between AT2 and AT1 cell phenotypes. The transcription factor (TF) GATA-6 has been shown to be essential for AT1 cell differentiation during development. The goal of this proposal is to investigate the role of GATA-6 in regulating transitions between AT2 and AT1 cell phenotypes through reciprocal activation and repression of differentiation-related genes, with the long-range objective of understanding how regulation of AEC differentiation contributes to maintenance and repair of adult alveolar epithelium following injury. We hypothesize that: 1) activation and repression of cell type-specific genes that accompany transitions between AT1 and AT2 cell phenotypes in alveolar epithelium in adult lung are modulated by reciprocal up- or down-regulation/interactions of TF; 2) changes in the relative expression/activity of GATA-6 regulate transitions between AT2 and AT1 cell phenotypes; and 3) combinatorial interactions of GATA-6 with other cofactors or cell-restricted TF determine the state of AEC differentiation. We will capitalize on our established in vitro culture systems and success in isolating both AT2 and AT1 cells, together with expertise in characterizing AEC differentiation, to explore these hypotheses by addressing the following Specific Aims: 1) investigate the role of GATA-6 expression in regulation of AEC differentiated phenotype, 2) determine effects of modulating GATA-6 expression on AEC differentiated phenotype, and 3) investigate regulation of AEC differentiation by characterizing interactions of GATA-6 with cell-type specific genes and other cell-restricted TF. The role of GATA-6 in AEC differentiation will be elucidated by evaluating its expression in isolated and cultured AEC and in situ, modulating GATA-6 expression and assessing effects on AEC phenotype, and characterizing its interactions with and promoter occupancy of an AT1 cell-specific gene, aquaporin-5, in AT2 vs. AT1 cells. These studies will provide novel insights into molecular programming of AEC differentiation, which will form the basis for further studies to develop new therapeutic strategies for recovery from lung injury.

描述（由申请人提供）：一般认为，肺泡上皮II型（AT2）细胞在发育和损伤后作为I型（AT1）细胞的祖细胞，恢复肺泡气体交换表面。然而，介导肺泡上皮细胞（AEC）表型分化的转录程序几乎完全未知。我们已经开发了定义良好的原代细胞培养系统，在该系统中，体外AEC转分化可以通过实验调节，为解剖调节AT2和AT1细胞表型之间转变的分子途径提供了一个极好的模型。转录因子（TF） GATA-6已被证明在AT1细胞发育过程中分化是必不可少的。本研究的目的是研究GATA-6通过相互激活和抑制分化相关基因在调节AT2和AT1细胞表型转换中的作用，以了解AEC分化的调节如何有助于成人肺泡上皮损伤后的维持和修复。我们假设：1)成人肺泡上皮中伴随AT1和AT2细胞表型转换的细胞类型特异性基因的激活和抑制是由TF的相互上调或下调/相互作用调节的；2) GATA-6相对表达/活性的变化调节AT2和AT1细胞表型之间的转换；3) GATA-6与其他辅因子或细胞限制性TF的组合相互作用决定了AEC分化的状态。我们将利用我们已建立的体外培养系统和分离AT2和AT1细胞的成功，以及表征AEC分化的专业知识，通过解决以下具体目标来探索这些假设：1)研究GATA-6表达对AEC分化表型的调控作用；2)确定调节GATA-6表达对AEC分化表型的影响；3)通过表征GATA-6与细胞型特异性基因和其他细胞限制性TF的相互作用来研究AEC分化的调控作用。GATA-6在AEC分化中的作用将通过评估其在分离和培养的AEC和原位中的表达，调节GATA-6的表达和评估对AEC表型的影响，以及在AT2和AT1细胞中表征其与AT1细胞特异性基因水通道蛋白-5的相互作用和启动子占据来阐明。这些研究将为AEC分化的分子编程提供新的见解，为进一步研究开发肺损伤恢复的新治疗策略奠定基础。