Ciornei Cristina D, Sigurdardóttir Thorgerdur, Schmidtchen Artur, Bodelsson Mikael
Department of Anesthesiology and Intensive Care, Lund, Sweden.
Antimicrob Agents Chemother. 2005 Jul;49(7):2845-50. doi: 10.1128/AAC.49.7.2845-2850.2005.
Antimicrobial peptides have been evaluated in vitro and in vivo as alternatives to conventional antibiotics. Apart from being antimicrobial, the native human cathelicidin-derived peptide LL-37 (amino acids [aa] 104 to 140 of the human cathelicidin antimicrobial peptide) also binds and neutralizes bacterial lipopolysaccharide (LPS) and might therefore have beneficial effects in the treatment of septic shock. However, clinical trials have been hampered by indications of toxic effects of LL-37 on mammalian cells and evidence that its antimicrobial effects are inhibited by serum. For the present study, LL-37 was compared to two less hydrophobic fragments obtained by N-terminal truncation, named 106 (aa 106 to 140) and 110 (aa 110 to 140), and to a previously described more hydrophobic variant, the 18-mer LLKKK, concerning antimicrobial properties, lipopolysaccharide neutralization, toxicity against human erythrocytes and cultured vascular smooth muscle cells, chemotactic activity, and inhibition by serum. LL-37, fragments 106 and 110, and the 18-mer LLKKK inhibited the growth of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, and Candida albicans in a radial diffusion assay, inhibited lipopolysaccharide-induced vascular nitric oxide production, and attracted neutrophil granulocytes similarly. While fragments 106 and 110 caused less hemolysis and DNA fragmentation in cultured cells than did LL-37, the 18-mer LLKKK induced severe hemolysis. The antibacterial effect of fragments 106 and 110 was not affected by serum, while the effect of LL-37 was reduced. We concluded that the removal of N-terminal hydrophobic amino acids from LL-37 decreases its cytotoxicity as well as its inhibition by serum without negatively affecting its antimicrobial or LPS-neutralizing action. Such LL-37-derived peptides may thus be beneficial for the treatment of patients with sepsis.
抗菌肽已在体外和体内作为传统抗生素的替代品进行了评估。除了具有抗菌作用外，天然人源cathelicidin衍生肽LL-37（人cathelicidin抗菌肽的氨基酸[aa]104至140）还能结合并中和细菌脂多糖（LPS），因此可能对治疗脓毒性休克有有益作用。然而，临床试验受到LL-37对哺乳动物细胞毒性作用迹象以及其抗菌作用受血清抑制的证据的阻碍。在本研究中，将LL-37与通过N端截短获得的两个疏水性较低的片段（命名为106（aa 106至140）和110（aa 110至140））以及先前描述的疏水性更强的变体18聚体LLKKK在抗菌特性、脂多糖中和、对人红细胞和培养的血管平滑肌细胞的毒性、趋化活性以及血清抑制方面进行了比较。LL-37、片段106和110以及18聚体LLKKK在径向扩散试验中均抑制大肠杆菌、铜绿假单胞菌、金黄色葡萄球菌和白色念珠菌的生长，抑制脂多糖诱导的血管一氧化氮产生，并且同样吸引中性粒细胞。虽然片段106和110在培养细胞中引起的溶血和DNA片段化比LL-37少，但18聚体LLKKK诱导严重溶血。片段106和110的抗菌作用不受血清影响，而LL-37的作用则降低。我们得出结论，从LL-37中去除N端疏水性氨基酸可降低其细胞毒性以及血清对其的抑制作用，而不会对其抗菌或LPS中和作用产生负面影响。因此，这种源自LL-37的肽可能对脓毒症患者的治疗有益。
