Synthetic Lung Surfactant Optimized for Biomedical Application

描述（由申请人提供）：动物源性表面活性剂制剂对早产儿呼吸窘迫综合征（RDS）的预防和治疗非常有效，但对急性肺损伤（ALI）和急性呼吸窘迫综合征（ARDS）的儿科和成人患者无效。ALI/ARDS的有效治疗可能需要具有最大表面活性的合成表面活性剂，并具有抵抗血管渗漏和急性炎症引起的表面活性剂抑制的能力。这种合成制剂具有大规模生产、成分可重复性好、易于质量控制、稳定性好、保质期长、不传播动物疾病、成本低等优点。合成表面活性剂还允许使用新的蛋白质和脂质成分，这些成分可能具有更强的抗抑制性，并且具有比现有表面活性剂配方更好的生物物理特性。我们的实验室设计、合成并表征了几种高活性的表面活性剂蛋白B （SP-B）类似物，如“Mini-B”（即SP-B的N端和c端交联结构）和“Super Mini-B”（即在N端有插入序列的Mini-B），并观察到与天然SP-B蛋白相比，Super-Mini-B进一步提高了合成表面活性剂制剂的表面活性。将这些SP-B类似物混合在无毒的磷脂酶抗性脂质中，即双棕榈酰磷脂酰胆碱（DPPC）和磷脂酰甘油（PG）的磷脂类似物中，将增强抑制抗性。本提案的具体目的是：(1)重新设计，合成和表征新的合成SP-B类似物，设计具有高脂结合，表面活性和抗（磷脂酶抗性）脂质混合物中的抑制和氧化应激；(2)确定合成表面活性剂在油酸或脂多糖（LPS）诱导的急性肺损伤家兔中的体内功效。我们假设，在使用离散氨基酸取代的基础上，对Mini-B和Super Mini-B进行额外的重组，将最大限度地提高它们各自的脂质结合和表面活性，并提高它们对抑制和氧化应激的抵抗力。在抗磷脂酶脂质混合物中配制这些重新设计的SP-B类似物可能提供一种独特的合成表面活性剂制剂，能够治疗ALI/ARDS。项目的叙述。急性肺损伤（ALI）和急性呼吸窘迫综合征（ARDS）是危及生命的呼吸系统疾病，可影响儿童和成人脓毒症、肺炎、胃误吸、烧伤、创伤和其他急性疾病。生存依赖于辅助通气、基础疾病的治疗和肺部表面活性物质抑制的逆转。重组必需的表面活性剂蛋白B和主要脂质以增强对抑制和氧化应激的抵抗力，可能会提供一种独特的合成表面活性剂制剂，可以治疗ALI/ARDS。

DESCRIPTION (provided by applicant): Animal-derived surfactant preparations are highly effective in preventing and treating respiratory distress syndrome (RDS) in premature infants, but not in pediatric and adult patients with acute lung injury (ALI) and the acute respiratory distress syndrome (ARDS). Effective therapy for ALI/ARDS will probably require synthetic surfactant with maximal surface activity and the ability to resist surfactant inhibition due to vascular leakage and acute inflammation. Such synthetic preparations offer the advantages of large-scale production, compositional reproducibility, easier quality control, stability with a long shelf-life, no transmission of animal disease, and lower costs. Synthetic surfactants also allow the use of novel protein and lipid components that may be more inhibition-resistant and possess biophysical properties that outperform native surfactant formulations than are presently available. Our laboratory has designed, synthesized, and characterized several highly-active analogs of surfactant protein B (SP-B), such as "Mini-B" (i.e., cross-linked construct of the N- and C-terminal domains of SP-B) and "Super Mini-B" (i.e., Mini-B with an insertion sequence at the N-terminus), and observed that Super-Mini-B further enhances the surface activity of synthetic surfactant preparations over that seen with native SP-B proteins. Mixing these SP-B analogs in non-toxic phospholipase-resistant lipids, i.e. phosphonolipid analogs of dipalmitoyl phosphatidylcholine (DPPC) and phosphatidylglycerol (PG), will promote inhibition resistance. The specific aims of this proposal are to (1) re-engineer, synthesize and characterize novel synthetic SP-B analogs designed to have high lipid-binding, surface activity and resistance to inhibition and oxidative stress in (phospholipase-resistant) lipid mixtures, and (2) define the in vivo efficacy of synthetic surfactants in rabbits with oleic acid- or lipopolysaccharide (LPS)-induced acute lung injury. We hypothesize that additional re-engineering of Mini-B and Super Mini-B, based on using discrete amino acid substitutions, will maximize their respective lipid binding and surface activity, and also increase their resistance to inhibition and oxidative stress. Formulation of these re-engineered SP-B analogs in phospholipase-resistant lipid mixtures may deliver a synthetic surfactant preparation uniquely able to treat ALI/ARDS. PROJECT NARRATIVE. Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are life-threatening respiratory diseases, which affect children and adults with sepsis, pneumonia, gastric aspiration, burns, trauma, and other acute illnesses. Survival depends on assisted ventilation, treatment of the underlying disease, and reversal of surfactant inhibition in the lung. Re-engineering of the essential surfactant protein B and the predominant lipids to enhance resistance to inhibition and oxidative stress may deliver a synthetic surfactant preparation uniquely able to treat ALI/ARDS.