Gene silencing therapeutics for chronic infections in cystic fibrosis

描述（由申请人提供）：革兰氏阴性病原体对当前使用的抗菌剂的耐药性越来越强。此外，新抗生素的管道很小，迫切需要新的治疗方法。这在患有慢性感染的患者中尤其成问题。固有耐药性革兰氏阴性病原体的实例是铜绿假单胞菌和洋葱伯克霍尔德氏菌复合体（Bcc）。这些病原体在各种情况下引起疾病，但在囊性纤维化（CF）患者中尤其具有破坏性。慢性铜绿假单胞菌或BCC感染可导致进行性肺功能下降，以及在BCC感染时，肺功能迅速恶化，称为“洋葱综合征”。“我们一直有兴趣使用称为PPMO的反义分子作为这些感染的潜在治疗剂。这些分子阻断信使RNA并阻断蛋白质的形成。我们已经证明，PPMOs可用于靶向这些病原体生长所必需的基因，特别是基因acpP（编码蛋白质酰基载体蛋白）。我们发现，阻断这种蛋白质是伯克霍尔德氏菌和假单胞菌在体外生长所必需的。我们还表明，这种PPMO提高了感染伯克霍尔德氏菌的小鼠的存活率。对于这个项目，我们建议在这些病原体中找到可以用PPMO阻断的其他必需基因靶点，并进行研究以评估最有前途的化合物提高小鼠感染模型存活率的能力。在该项目的第一阶段，我们将针对在其他革兰氏阴性病原体中已被证明对生长至关重要的途径。这些将包括在细胞壁和相关结构（脂多糖和肽聚糖生物合成）以及脂肪酸生物合成（即酰基载体蛋白）的发育中重要的基因。此外，我们将尝试阻断在抗生素耐药性中发挥作用的基因，看看我们是否可以恢复现有抗生素的活性。该项目的第二阶段将是在小鼠感染模型中评估主要PPMO候选物。我们将使用PPMO作为肺部感染模型的治疗，评估化合物的全身和肺部递送。通过这项研究的结论，我们希望能够为CF中两种最具破坏性的病原体提供有希望的新治疗方法，从而进一步推动临床开发。这项工作不仅对CF中的这些感染有影响，而且对其他医学上重要的革兰氏阴性病原体也有影响。

DESCRIPTION (provided by applicant): Gram-negative pathogens are becoming increasingly resistant to currently used antimicrobials. Furthermore, the pipeline for new antibiotics is slim and new therapies are urgently needed. This can be especially problematic in patients who suffer from chronic infections. Examples of inherently drug resistant Gram-negative pathogens are Pseudomonas aeruginosa and the Burkholderia cepacia complex (Bcc). These pathogens cause disease in a variety of settings, but are particularly devastating in patients with cystic fibrosis (CF). Chronic P. aeruginosa or Bcc infection can lead to both progressive pulmonary decline, as well as in Bcc infection, rapid deterioration in lung function referred to as "cepacia syndrome." We have been interested in using antisense molecules called PPMOs as potential therapeutics in these infections. These molecules block messenger RNA and block the formation of protein. We have demonstrated that PPMOs can be used to target genes that are essential for these pathogens to grow, specifically the gene acpP (that encodes the protein acyl carrier protein). We showed that blocking this protein is essential for Burkholderia and Pseudomonas to grow in vitro. We also showed that this PPMO improves survival in mice that were infected with Burkholderia. For this project, we propose to find other essential gene targets in these pathogens that can be blocked with PPMOs, and perform studies to evaluate the most promising compounds ability to improve survival in mouse models of infection. In the first phase of the project, we will target pathways that have been shown in other Gram-negative pathogens to be essential for growth. These will include genes important in the development of the cell wall and associated structures (lipopolysaccharide and peptidoglycan biosynthesis) as well as fatty acid biosynthesis (i.e. acyl carrier protein). In addition, we will try to block the genes that pla a role in antibiotic resistance to see if we can restore activity of currently existing antibiotics. he second phase of the project will be to evaluate lead PPMO candidates in mouse models of infection. We will use the PPMOs as treatments in pulmonary models of infection, assessing both systemic and pulmonary delivery of the compound. By the conclusion of this study, we hope to have promising novel treatments for two of the most devastating pathogens in CF that could advance to further clinical development. This work has implications not only for these infections in CF, but for other medically important Gram-negative pathogens.