Bucki Robert, Sostarecz Audra Goach, Byfield Fitzroy J, Savage Paul B, Janmey Paul A
Department of Physiology and the Institute for Medicine and Engineering, 1010 Vagelos Research Laboratories, University of Pennsylvania, 3340 Smith Walk, Philadelphia, PA 19104, USA.
J Antimicrob Chemother. 2007 Sep;60(3):535-45. doi: 10.1093/jac/dkm218. Epub 2007 Jun 21.
The goal of this study was to evaluate the effects of DNA and F-actin [polyanions present in high concentration in cystic fibrosis (CF) airway fluid] on the antibacterial activities of the cationic steroid antibiotic CSA-13 and the cationic peptides LL37, WLBU2 and HB71.
Light scattering intensity was used to evaluate the aggregation of DNA and F-actin by the cationic antibacterial agents. Bacterial killing assays, atomic force microscopy, determination of MIC values and bacterial load of CF sputa were used to determine the bactericidal activity. Inhibition of nuclear factor-kappaB (NF-kappaB) translocation in human aorta endothelial cells (HAECs) was quantified as an assay of anti-inflammatory action.
CSA-13 is significantly more effective than cationic antibacterial peptides against kanamycin-resistant Pseudomonas aeruginosa and less susceptible to inactivation by DNA or F-actin. The concentration of CSA-13 sufficient to decrease the CF sputa bacteria load by approximately 90% is at least 10 times lower than that at which CSA-13 formed aggregates with DNA or F-actin. Both CSA-13 and LL37 prevent lipopolysaccharide-induced translocation of NF-kappaB in HAEC, thereby suggesting that these antibacterial molecules might prevent systemic inflammation caused by bacterial wall components.
Charge-based interactions that strongly inhibit the antibacterial activity of host cationic antibacterial peptides present in CF sputa have significantly less effect on molecules from the ceragenin family such as CSA-13 due in part to their smaller net charge and distribution of this charge over a hydrophobic scaffold. CSA molecules therefore have potential for the treatment of chronic infections and inflammation that occur in CF airways and other settings in which extracellular polyanions accumulate.
本研究的目的是评估DNA和F-肌动蛋白（囊性纤维化（CF）气道液中高浓度存在的聚阴离子）对阳离子甾体抗生素CSA-13以及阳离子肽LL37、WLBU2和HB71抗菌活性的影响。
利用光散射强度评估阳离子抗菌剂对DNA和F-肌动蛋白的聚集作用。采用细菌杀伤试验、原子力显微镜、最低抑菌浓度（MIC）值测定以及CF痰液细菌载量测定来确定杀菌活性。将人主动脉内皮细胞（HAECs）中核因子-κB（NF-κB）易位的抑制情况作为抗炎作用的检测指标进行定量分析。
CSA-13对耐卡那霉素的铜绿假单胞菌的抗菌效果明显优于阳离子抗菌肽，且较不易被DNA或F-肌动蛋白灭活。使CF痰液细菌载量降低约90%的CSA-13浓度至少比CSA-13与DNA或F-肌动蛋白形成聚集体时的浓度低10倍。CSA-13和LL37均可阻止脂多糖诱导的HAEC中NF-κB易位，从而表明这些抗菌分子可能预防由细菌壁成分引起的全身炎症。
基于电荷的相互作用会强烈抑制CF痰液中宿主阳离子抗菌肽的抗菌活性，但对ceragenin家族分子如CSA-13的影响要小得多，部分原因是其净电荷较小且电荷分布在疏水支架上。因此，CSA分子在治疗CF气道及其他细胞外聚阴离子积累环境中发生的慢性感染和炎症方面具有潜力。
