Epigenic Control of ENaC Transcription and Sodium Transport

ENaC 转录和钠转运的表观遗传控制

基本信息

批准号：
7769494
负责人：
WENZHENG ZHANG
金额：
$ 35.24万
依托单位：
UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-03-01 至 2014-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7769494
关键词：
5&apos Flanking Region Acid-Base Equilibrium Adult Age Aldosterone Alternative Splicing American American Heart Association Animals Apical Binding Binding Sites Birth Blood Pressure Cell membrane Cell surface Cells Cessation of life Chromatin Chromosomes, Human, Pair 9 Competitive Binding Complex Coupled Couples DNA DNA Binding Defect Development Down-Regulation Duct (organ) structure Epigenetic Process Epithelial Equilibrium Event Figs - dietary Friends Genes Genetic Transcription Genetically Engineered Mouse Genome Glucocorticoid Receptor Goals Grant Histone H3 Homeostasis Hypermethylation In Vitro Ion Channel Kidney Ligands Light Link Mediating Methylation Methyltransferase Mineralocorticoid Receptor Mineralocorticoids Modeling Molecular Molecular Target Mus Mutation Nephrology Nuclear Nuclear Receptors Pathway interactions Phenotype Phosphorylation Physiological Play Proteins Pseudohypoaldosteronism Regulation Reporting Repression Research Role Series Sgk protein Signal Pathway Signal Transduction Site Societies Sodium Sodium Channel Syndrome Testing Text Transactivation Transcriptional Activation Transcriptional Regulation Translating Translations Variant absorption base blood pressure regulation chromatin modification derepression epithelial Na+ channel gene repression in vivo mRNA Expression malignant breast neoplasm mouse model neonate novel promoter public health relevance steroid hormone transcription factor uptake

项目摘要

DESCRIPTION (provided by applicant): The broad goal of this project is to define novel epigenetic mechanisms controlling Na+ homeostasis in mIMCD3 cells and in mouse kidney, with ENaC (epithelial sodium channel) as the model. The association of ENaC mutations with Liddle's syndrome and PHA-1 (pseudohypoaldosteronism type 1) as well as the tight and complex regulation of ENaC by aldosterone indicates the importance of ENaC in the regulation of Na+ balance and blood pressure. Aldosterone is a major regulator of Na+ absorption and acts primarily by controlling ENaC function at multiple levels, including transcription and cell surface expression. In the classical model, aldosterone enhances transcription by activating two distinct but similar types of NR (nuclear receptors): MR and GR (mineralocorticoid and glucocorticoid receptors). MR disruption in mouse leads to PHA-1 and animal death around day 10 after birth. Recently, we reported an alternative signaling pathway that couples aldosterone action to chromatin modifications and ENaC1 transcriptional activation through a series of events including reduction of histone H3 K79 methyltransferase Dot1a (disruptor of telomeric silencing 1) and putative transcription factor AF9 (ALL1-fused gene from chromosome 9), SGK1 (serum and glucocorticoid regulated kinase)-mediated phosphorylation of AF9 and thus downregulation of Dot1a-AF9 interaction, and targeted histone H3 K79 hypomethylation at the ENaC1 promoter in mIMCD3 cells. Despite these findings, the putative antagonism between the NR/aldosterone and Dot1a/AF9 complexes remains unaddressed; the correlation between aldosterone-stimulated ENaC transcription and ENaC activity is still not well defined; and the molecular defects derived from MR disruption that result in PHA-1 remain elusive. In this proposal, we intend to fill these gaps. In Aim 1, we will test the hypothesis that the NR-aldosterone and Dot1a-AF9 complexes mutually inhibit the DNA binding activity of their opponent through MR-AF9 and/or GR-AF9 interactions to dynamically control ENaC1 transcription in mIMCD3 cells; Aim 2 will test the hypothesis that changes in ENaC transcription translate into changes in ENaC activity in mIMCD3 cells; and Aim 3 will examine MR-/- mice more fully to test the hypothesis that the components in our new aldosterone network and other ENaC regulatory factors are deregulated by MR deficiency, which contributes to the development of PHA-1, and to confirm the mutual antagonism of the two complexes on ENaC transcription and activity as defined in Aim 1 and 2. Therefore, the proposed studies will 1) integrate the two modes of aldosterone action: activation of NR and relief of Dot1a-AF9-mediated repression; 2) link aldosterone action to chromatin-mediated ENaC transcriptional activation, enhanced ENaC activity and Na+ transport; and 3) shed new light on molecular mechanisms of PHA-1 development. PUBLIC HEALTH RELEVANCE Na+ balance is important for blood pressure control and is primarily achieved by the molecular action of the steroid hormone aldosterone on ENaC, an ion channel that transports Na+ through the cell membrane into the cells. The proposed studies are aimed to define novel mechanisms linking aldosterone action to chromatin modifications, transcriptional activation of ENaC, and enhanced Na+ uptake in mouse kidney, using one existing genetically engineered mouse model.

描述（由申请人提供）：该项目的广泛目标是将控制MIMCD3细胞中Na+稳态的新型表观遗传机制定义为MIMCD3细胞和小鼠肾脏中，并以ENAC（上皮钠通道）为模型。 ENAC突变与Liddle综合征和PHA-1（假氧化醛型1型）以及醛固酮对ENAC的紧密调控的关联表明ENAC在调节Na+平衡和血压调节中的重要性。醛固酮是Na+吸收的主要调节剂，主要是通过在多个级别（包括转录和细胞表面表达）控制ENAC功能来起作用。在经典模型中，醛固酮通过激活两种不同但类似类型的NR（核受体）来增强转录：MR和GR（矿物皮质激素和糖皮质激素受体）。小鼠中的MR干扰导致PHA-1和动物死亡在出生后第10天左右。 Recently, we reported an alternative signaling pathway that couples aldosterone action to chromatin modifications and ENaC1 transcriptional activation through a series of events including reduction of histone H3 K79 methyltransferase Dot1a (disruptor of telomeric silencing 1) and putative transcription factor AF9 (ALL1-fused gene from chromosome 9), SGK1 (serum and glucocorticoid regulated激酶）介导的AF9的磷酸化，从而下调DOT1A-AF9相互作用，并在MIMCD3细胞中的ENAC1启动子处靶向组蛋白H3 K79低甲基化。尽管有这些发现，但NR/醛固酮和DOT1A/AF9复合物之间的假定拮抗作用仍未得到解决。醛固酮刺激的ENAC转录和ENAC活性之间的相关性仍未得到很好的定义；以及导致PHA-1的MR中断产生的分子缺陷仍然难以捉摸。在此提案中，我们打算填补这些空白。在AIM 1中，我们将检验以下假设：NR-醛固酮和DOT1A-AF9复合物通过MR-AF9和/或GR-AF9相互作用在MIMCD3细胞中通过MR-AF9和/或GR-AF9相互作用互相抑制对手的DNA结合活性。 AIM 2将检验以下假设：ENAC转录的变化转化为MIMCD3细胞中ENAC活性的变化；目标3将更充分地检查MR - / - 小鼠，以检验以下假说：我们新的醛固酮网络中的组成部分和其他ENAC调节因素通过MR缺乏症解除了管制，这有助于PHA-1的发展，并确认两个复合物在ENAC转录和活动中的相互对抗，如AIM 1和2的行动：拟定的。并缓解DOT1A-AF9介导的抑制作用； 2）将醛固酮作用与染色质介导的ENAC转录激活，增强的ENAC活性和Na+转运联系起来； 3）对PHA-1发育的分子机制开发了新的启示。公共卫生相关性 Na+平衡对于血压控制很重要，主要是通过类固醇激素醛固酮在ENAC上的分子作用来实现的，ENAC是一种离子通道，该通道将Na+通过细胞膜传输到细胞中。拟议的研究旨在使用一种现有的基因工程小鼠模型来定义将醛固酮作用与染色质修饰，ENAC的转录激活以及增强的Na+摄取的新型机制。