Novel molecular therapeutics for cystic fibrosis

描述(申请人提供)：全世界大约有70,000人患有囊性纤维化(CF)这种衰弱的疾病，这种疾病通常是致命的，原因是脓毒症。 肺内异常粘稠的粘液。各种治疗方法被用来解决症状，但迫切需要一种针对CF病因的经批准的药物。其原因是CFTRF508突变，它异常地调节细胞内外的盐分水平，导致疾病病理。该突变导致CFTR蛋白的不正确折叠，使其大部分在细胞合成后(ERAD)的内质网(ER)中降解，不能到达细胞膜。定位于细胞膜的CFTRF508具有部分功能，被称为校正剂(如VX-809)的药物正在开发中，以促进突变的CFTR向细胞表面的运输。针对cftr的ERAD泛素E3连接酶之一是环连接酶gp78，而gp78的敲除会导致细胞中cftr？F508水平的显著增加。此外，含有催化死亡gp78的细胞的特征是CFTRF508泛素化减少。由于cftr？F508水平的上调，gp78抑制有可能增加细胞表面cftr的数量，特别是与VX-809等校正剂联合使用时。因此，gp78被认为是开发小分子抑制剂治疗CF的新靶点，通过增加功能性CFTR的水平，从而改善CF患者肺内粘液的调节。Progenra已经开发出一种检测技术，已经确定了各种环E3连接酶的小分子抑制剂；这些抑制剂目前正在进行临床前开发。我们建议将这一方法用于筛选人类gp78抑制剂，并对可作为治疗药物的小分子进行中试筛选。将开发自动素化和底物泛素化分析，从多样性文库中筛选40,000种化合物，并根据HITS反筛选确定的效力和选择性确定合适的抑制剂。将建立适当的细胞模型，并开始对选定的抑制剂进行细胞概念验证研究。在第二阶段，将进行更广泛的筛选，选定的gp78先导抑制剂将进行临床前开发(化学优化、DMPK、体内疗效研究)，单独治疗CF或与VX-809等校正药物联合治疗。 与公共卫生相关：尽管采用了各种治疗方法来解决囊性纤维化(CF)这种衰弱疾病的症状，但迫切需要一种针对囊性纤维化病因的经批准的药物。一种名为cftr的蛋白质负责维持细胞膜上适当的盐平衡，在cf中，它被突变和降解，导致失衡和过度粘膜，从而成为败血症，从而导致死亡。Progenra建议开发一种酶的小分子抑制剂(Gp78)，它可以降解这种突变的蛋白质，以恢复盐平衡并实现治疗效果。

DESCRIPTION (provided by applicant): Approximately 70,000 individuals worldwide suffer from the debilitating disease cystic fibrosis (CF), which typically is fatal owing to sepsis in the abnormally viscous mucus of the lung. Various treatments are employed to address symptoms, but an approved drug that acts on the cause of CF is urgently needed. The cause is the ?F508 mutation of the CF (CFTR), which aberrantly regulates levels of salts inside and outside cells, leading to the disease pathologies. The mutation causes improper folding of the CFTR protein, so that most of it is degraded in the endoplasmic reticulum (ER) in the cell post-synthesis (ERAD) and does not reach the cell membrane. CFTR?F508 that does localize to the membrane is partially functional, and drugs called correctors (e.g., VX-809) are being developed to promote trafficking of mutant CFTR to the cell surface. One of the ERAD ubiquitin E3 ligases that target CFTR is the RING ligase gp78, and knockdown of gp78 leads to dramatically increased levels of CFTR?F508 in cells. Moreover, cells containing catalytically dead gp78 are characterized by reduced ubiquitylation of CFTR?F508. Due to upregulation of CFTR?F508 levels, gp78 inhibition has the potential to increase the amount of CFTR at cell surfaces, especially in combination with correctors such as VX-809. It is thus proposed that gp78 is a novel target for developing small molecule inhibitors for treating CF by increasing levels of functional CFTR, thereby improving the regulation of mucus in the lungs of CF patients. Progenra has developed an assay technology that has identified small molecule inhibitors of various RING E3 ligases; these inhibitors are currently undergoing pre-clinical development. It is proposed here to adapt and validate this assay for screening for inhibitors of human gp78 and conduct a pilot screen for small molecules that can be developed as therapeutic agents for CF. Autoubiquitylation and substrate ubiquitylation assays will be developed, 40,000 compounds from a diversity library will be screened, and suitable inhibitors will be identified based on potency and selectivity as determined by counter-screening of the hits. An appropriate cellular model will be established and cell proof of concept studies initiated on selected inhibitors. In Phase II, more extensive screening will be conducted and selected lead gp78 inhibitors will undergo preclinical development (chemical optimization, DMPK, in vivo efficacy studies) for treatment of CF singly or in combination with correctors such as VX-809. PUBLIC HEALTH RELEVANCE: Although various treatments are employed to address symptoms of the debilitating disease cystic fibrosis (CF), an approved drug that acts on the cause of CF is urgently needed. A protein called CFTR is responsible for maintaining proper salt balance at cell membranes and in CF it is mutated and degraded, leading to imbalance and overly mucous membranes that become septic leading to mortality. Progenra proposes to develop a small molecule inhibitor of the enzyme (gp78) that degrades this mutated protein to restore salt balance and achieve therapeutic benefit.