Development of a Biomimetic Lung Surfactant Replacement

描述（由申请人提供）：使用有效且低成本的仿生肺表面活性物质（LS）替代品可以更好且更广泛地治疗几种呼吸道疾病和病症。在目前的医疗实践中，LS替代品（主要用于治疗新生儿呼吸窘迫综合征）来源于动物肺，价格昂贵，并具有病毒传播和免疫反应的风险。我们建议继续开发一类新的功能模拟的肺表面活性蛋白的基础上聚-N-取代甘氨酸（类肽），这是序列特异性杂聚物合成的固相，类似于肽。类肽具有蛋白酶抗性，并且通过适当的序列设计可以形成稳定的螺旋二级结构，其抵抗非特异性聚集。在过去的3.5年中，我们已经创建并研究了两种不同的新型螺旋两亲性类肽寡聚体，其序列和结构与（1）SP-B（残基1-25）和（2）SP-C（残基5-32）相似。在体外生物物理研究的表面活性，这些基于类肽的SP模拟在LS样脂质膜证明，最好的设计内的每一类模拟执行类似的天然肽，它们被设计为取代。虽然最初的结果是非常有希望的，但仍有许多工作要做，以开发基于类肽的SP模拟物，用于临床上有用的仿生LS替代品。我们现在必须更深入地了解两类两亲性类肽SP模拟物的结构-活性关系。我们建议通过改变关键的结构特征和对表面活性的影响进行详细的研究，与分子动力学模拟并行。对于SP-C模拟物，我们将研究疏水螺旋长度、侧链化学和总体螺旋度的影响，并且还将模拟天然SP-C的棕榈酰化。提出的SP-B模拟物将具有越来越多的蛋白质样序列和侧链化学，我们将测试二聚化将提高其活性的假设。我们将使用CD、脉动气泡表面测量法、朗缪尔槽/Wilhelmy表面平衡、荧光显微镜、单层囊泡和X射线反射率/衍射对含类肽表面活性剂进行体外研究，以绘制结构-活性关系并研究类肽-脂质相互作用。我们将调查表面活性剂配方含有模拟两个SP，我们将研究的bicompatibility和类肽表面活性剂与肺上皮细胞和RDS动物模型的体内疗效。

DESCRIPTION (provided by applicant): Several respiratory diseases and disorders could be better and more widely treated with an effective and low-cost biomimetic lung surfactant (LS) replacement. In present medical practice, LS replacements (used predominantly to treat neonatal respiratory distress syndrome) derive from animal lungs, are expensive, and carry risks of viral transmission and immune response. We propose to continue the development of a novel class of functional mimics of the lung surfactant proteins based on poly-N-substituted glycines (peptoids), which are sequence-specific heteropolymers synthesized on solid phase, similarly to peptides. Peptoids are protease resistant, and with proper sequence design can form stable, helical secondary structures that resist non-specific aggregation. Over the past 3.5 years, we have created and studied two different, novel classes of helical, amphipathic peptoid oligomers with sequence and structural similarity to (1) SP-B (residues 1-25) and (2) SP-C (residues 5-32). In vitro biophysical studies of the surface activities of these peptoid-based SP mimics in an LS-like lipid film demonstrate that the best designs within each class of mimics perform similarly to the natural peptides they are designed to replace. While initial results are very promising, much work remains to be done to develop peptoid-based SP mimics for a clinically useful, biomimetic LS replacement. We must now gain a deeper understanding of structure-activity relationships for the two classes of amphiphilic peptoid SP mimics under study. We propose to do this by varying key structural features and performing detailed studies of the effects on surface activity, in parallel with Molecular Dynamics simulations. For SP-C mimics, we will study the effects of hydrophobic helix length, side chain chemistry and overall helicity, and will also mimic the palmitoylation of natural SP-C. Proposed SP-B mimics will have increasingly protein-like sequences and side chain chemistries, and we will test the hypothesis that dimerization will improve their activity. We will carry out in vitro studies of peptoid-containing surfactant using CD, pulsating bubble surfactometry, a Langmuir trough/Wilhelmy surface balance, fluorescence microscopy, unilamellar vesicles, and X-ray reflectivity/diffraction to map out structure-activity relationships and study peptoid-lipid interactions. We will investigate surfactant formulations containing mimics of both SPs, and we will study the bicompatibility and in vivo efficacy of peptoid surfactants with lung epithelial cells and animal models of RDS.