Prevention of C. Albicans Biofilms by Beta-Peptide Release From Thin Films

描述（由申请方提供）：白色念珠菌是从人体分离的最常见的真菌病原体，是医院获得性感染的主要原因。系统性念珠菌血症是一种常见的致死性疾病，通常与念珠菌有关。留置医疗器械表面形成的白色念珠菌生物膜。我们项目的目标是开发一种新的策略来预防C。导管上的白色念珠菌生物膜形成，从而降低高危患者中念珠菌血症的发生率。在先前的工作中，PI鉴定出<$-氨基酸的阳离子两亲性寡聚体（称为<$-肽）可以表现出高水平的抗C.白色念珠菌与哺乳动物细胞相比。这些？- 肽是基于与天然抗微生物肽的结构相似性设计的，天然抗微生物肽在与细胞膜结合时通常折叠成两亲性阳离子螺旋。然而，β-肽可以被设计成具有优于α-肽抗微生物肽的关键优点，包括在生理pH和离子强度下的活性、更大的结构稳定性和对蛋白水解降解的抗性。在此，我们将设计具有活性和选择性的螺旋肽化合物，并评估其预防C.体外和体内白念珠菌生物膜形成。此外，我们将研究混合α/<$-肽的特异性抗真菌活性，其也折叠成两亲性螺旋，并允许调节结构超出<$-肽。为了促进抗真菌肽和α/β-肽从医疗器械表面的递送，我们将设计以与预防导管应用中体内生物膜形成相关的速率掺入和释放肽的多层膜（PEM）膜。我们将评估膜厚度、膜交联、肽结构和化学性质如何影响释放速率。抗真菌肽和抗真菌肽抑制C.白色念珠菌生物膜的形成将通过测定生物膜形成速率和涂覆有肽掺入的PEM膜的基底上的生物膜结构来体外定量。然后使用大鼠中心静脉导管模型在体内评估优化的肽和释放策略。这些结果将共同测试从导管上的PEM膜递送肽寡聚体和肽寡聚体将抑制C的预测。白色念珠菌生物膜形成，并可能建立一个新的范例，用于预防设备相关的念珠菌血症。

DESCRIPTION (provided by applicant): Candida albicans is the most common fungal pathogen isolated from humans and is a leading cause of hospital-acquired infections. Systemic candidemia, an often fatal disease, is typically associated with C. albicans biofilms formed on the surface of indwelling medical devices. The goal of our project is to develop a novel strategy to prevent C. albicans biofilm formation on catheters, and to thereby reduce the incidence of candidemia in high-risk patients. In prior work the PI identified that cationic, amphiphilic oligomers of ¿-amino acids (called ¿-peptides) can exhibit high levels of specific activity against C. albicans as compared to mammalian cells. These ¿-peptides were designed based on structural similarity to natural antimicrobial peptides, which typically fold into amphiphilic cationic helices when associated with cellular membranes. However, ¿-peptides can be designed to possess key advantages over a-peptide antimicrobial peptides including activity at physiologic pH and ionic strength, greater structural stability, and resistance to proteolytic degradation. Here, we will design active and selective helical -peptides compounds and assess their ability to prevent C. albicans biofilm formation in vitro and in vivo. Additionally, we will investigate the specific antifungal activity of mixed a/¿-peptides, which also fold into amphiphilic helices, and permit regulation of structure beyond that of ¿-peptides. To facilitate delivery of antifungal ¿- and a/¿-peptides from the surface of medical devices we will design polyelectrolyte multilayer (PEM) films that incorporate and release the peptides at rates relevant for prevention of biofilm formation in vivo in catheter applications. We will assess how film thickness, film crosslinking, and peptide structures and chemical properties influence rate of release. The ability of antifungal ¿- and a/¿-peptides to inhibit C. albicans biofilm formation will be quantified in vitro by determining biofilm formation rate and biofilm structure on substrates coated with peptide-incorporated PEM films. Optimized peptides and release strategies will then be assessed in vivo using a rat central venous catheter model. Together these results will test the prediction that delivery of ¿- and a/¿-peptide oligomers from a PEM film on a catheter will inhibit C. albicans biofilm formation, and may establish a new paradigm for prevention of device-associated candidemia.