Epigenomic Modulation of Cystic Fibrosis

描述（由申请人提供）：囊性纤维化（CF）是一种遗传性蛋白质稳态功能丧失的儿童疾病（蛋白质稳态）。CF主要由囊性纤维化跨膜传导调节因子（?）中的Phe 508缺失引起。F508 CFTR)，一个多膜跨越，camp调节的氯离子通道。错误折叠和有效降解？内质网中的F508是胞外通路的第一步，它降低了蛋白质的稳定性，导致细胞表面电导丧失，过早肺衰竭和缩短寿命。CF是一大组错误折叠疾病的一员，包括儿童肺气肿、溶酶体储存缺陷、II型糖尿病和与衰老相关的蛋白质平衡缺陷的神经退行性病变。我们现在表明，通过用组蛋白去乙酰化酶（HDAC）抑制剂（HDACi）调节表观基因组，我们可以对肺细胞环境进行重编程，以实现在F508的合成、折叠、降解和运输导致细胞表面的电导（功能）。这一纠正事件发生在原代人支气管上皮细胞（HBE）的治疗上。F纯合子患者(HBE-CF-(?F/？F)使用临床批准的HDACi SAHA达到被认为对疾病有纠正作用的功能性细胞表面通道活性水平。小干扰（si） rna特异性敲低HDAC7导致肺细胞电导恢复，表明只有一小部分HDAC活性调节CFTR的折叠、稳定性、运输和功能。我们认为hvac控制着一个与蛋白质静止相关的转录程序，以实现蛋白质的折叠、稳定、运输和功能。在本提案中，我们建议开发特异性小分子来抑制HDAC7的功能（Aim 1），并探索HDAC7在CF生物学中的作用（Aim 2）。利用HDACi来化学调节相关的转录和蛋白质稳态环境，预计将对纠正人类错误折叠疾病产生重大影响。

DESCRIPTION (provided by applicant): Cystic fibrosis (CF) is an inherited loss-of-function childhood disease in protein homeostasis (proteostasis). CF is caused principally by the Phe 508 deletion in the cystic fibrosis transmembrane conductance regulator (?F508 CFTR), a multi-membrane spanning, cAMP-regulated chloride channel. Misfolding and efficient degradation of ?F508 in the endoplasmic reticulum, the first step in the exocytic pathway, reduces the stability of the protein resulting in the loss of cell surface conductance, premature lung failure and shortened lifespan. CF is a member of a large group of misfolding diseases including childhood emphysema, lysosomal storage deficiencies, type II diabetes and neurodegenerative pathologies associated with aging that are defective in proteostasis. We now show that by modulating the epigenome with histone deacetylase (HDAC) inhibitors (HDACi), we can reprogram the lung cell environment to achieve a productive balance between the rate of ?F508 synthesis, folding, degradation and trafficking leading to conductance (function) at the cell surface. This corrective event occurs upon treatment of primary human bronchial epithelial (HBE) cells obtained from ?F homozygous patients (HBE-CF-(?F/?F) with the clinically approved HDACi SAHA to a level of functional cell surface channel activity that is considered corrective for disease. Specific knockdown by small interfering (si)-RNA of HDAC7 results in recovery of conductance in lung cells, suggesting that only a subset of HDAC activities modulates CFTR folding, stability, trafficking and function. We suggest that HVACs control a transcriptional program that is linked to proteostasis to achieve folding, stability, trafficking and function of ?F508 that can be protective for CF. In this proposal, we propose to develop specific small molecules to inhibit HDAC7 function (Aim 1) and to explore the role of HDAC7 in CF biology (Aim 2). Use of HDACi to chemically modulate linked transcriptional and protein homeostasis environments is anticipated to have high impact on correction of human misfolding disease. PUBLIC HEALTH RELEVANCE: Cystic fibrosis (CF) is an inherited loss-of-function childhood disease caused by mutation of the cystic fibrosis transmembrane conductance regulator (?F508 CFTR), a critical chloride channel in the lung. Misfolding and degradation of the mutant channel results in the loss of cell surface conductance, premature lung failure and shortened lifespan. We show that by modulating the cellular epigenome (events that control gene expression in the nucleus through modification of DNA organization), we can reprogram the lung cell environment to correct disease, demonstrating that pharmacological modulation of the protein composition of the cell through a novel group of drugs can have a high impact on correction of human misfolding disease.