Development of antimicrobial peptide therapeutics for multidrug-resistant systemic bacterial infection

目前发现和开发新型抗生素的困难正在成为一个主要的卫生保健危机。随着抗菌素耐药性的出现，这种情况更具挑战性。该项目的基本假设是，α-螺旋肽的计算机设计为识别新型抗菌化合物提供了很好的可能性，这与时间效率和成本降低有关。该提案的长期目标是利用结构指导原则设计新型抗菌肽（AMP），这些抗菌肽将有效对抗由革兰氏阴性菌和革兰氏阳性菌引起的全身性细菌感染。我们的目标是设计具有合适的效力、选择性、稳定性和适当的PK/PD性质的短α-螺旋AMP。我们将通过三个具体目标来测试我们的中心假设：目标1）细菌特异性AMP的计算机设计，包括基于经典的3.613 α-螺旋核心（Pauling-Corey-Branson α-螺旋）的手动设计，该核心含有12个氨基酸残基，具有不同的电荷和疏水性平衡，然后使用AlphaFold 2进行分子动力学建模和结构预测。目的2）确定设计肽的活性、毒性、稳定性和作用机制。目的3）肽在大蜡螟模型中以及随后在全身性小鼠感染模型中的体内功效评估。此外，我们还将使用聚（乳酸-羟基乙酸共聚物）（PLGA）和/或壳聚糖纳米载体评估选定的、设计的AMP的纳米颗粒制剂，用于小鼠体内的潜在未来用途。在完成拟议目标后，将确定新的候选抗菌肽，这将有助于缓解当前的抗菌危机。

Current difficulties in discovering and developing novel antibiotics is becoming a major health care crisis. This situation is even more challenging with the emergence of antimicrobial resistance. The underlying hypothesis of the proposed project is that the design of α-helical peptides in silico offers excellent possibilities for identifying novel antimicrobial compounds with respect to time efficiency and cost reduction. The long-term goal of this proposal is to utilize structure-guided principles to design novel antimicrobial peptides (AMPs) in silico that will be effective against systemic bacterial infection caused by both Gram-negative bacteria and Gram-positive bacteria. We aim to engineer short α-helical AMPs with suitable potency, selectivity, stability, and appropriate PK/PD properties. We will test our central hypothesis with three specific aims: Aim 1) In silico design of bacteria-specific AMPs that includes manual design based on a classic 3.613 α-helix core (Pauling–Corey–Branson α-helix) containing 12 amino acid residues with varying charge and hydrophobicity balance followed by molecular dynamics modeling and structure predictions using AlphaFold2. Aim 2) Determine the activity, toxicity, stability, and mechanism of action of designed peptides. Aim 3) In vivo efficacy evaluation of peptides in a Galleria mellonella wax moth model and subsequently in a systemic mouse infection model. In addition, we will also evaluate nanoparticle formulations of selected, designed AMPs for potential future in vivo use in mice using a poly(lactic-co-glycolic acid) (PLGA) and/or chitosan nanocarrier. Upon completion of the proposed objectives, novel candidate AMPs will be identified that will help mitigate the current antimicrobial crisis.