Department of Infectious Diseases/Clinical Bacteriology, University of Gothenburg, Guldhedsgatan 10, S-413 46 Gothenburg, Sweden.
Int J Antimicrob Agents. 2011 Jan;37(1):51-7. doi: 10.1016/j.ijantimicag.2010.08.020. Epub 2010 Nov 13.
Owing to the increasing number of infections in hospitalised patients caused by resistant strains of fungi, there is a need to develop new therapeutic agents for these infections. Naturally occurring antimicrobial peptides may constitute models for developing such agents. A modified peptide sequence (CFQWKRAMRKVR; HLopt2) based on amino acid residues 20-31 of the N-terminal end of human lactoferrin (hLF) as well as a double-sized human lactoferricin-like peptide (amino acid residues 16-40; HLBD1) were investigated for their antifungal activities in vitro and in vivo. By in vitro assay, HLopt2 was fungicidal at concentrations of 12.5-25 μg/mL against Cryptococcus neoformans, Candida albicans, Candida krusei, Candida kefyr and Candida parapsilosis, but not against Candida glabrata. HLopt2 was demonstrated to have ≥ 16-fold greater killing activity than HLBD1. By inducing some helical formation caused by lactam bridges or by extending the assay time (from 2h to 20 h), HLBD1 became almost comparable with HLopt2 in its fungicidal activity. Killing of C. albicans yeast cells by HLopt2 was rapid and was accompanied by cytoplasmic and mitochondrial membrane permeabilisation as well as formation of deep pits on the yeast cell surface. In a murine C. albicans skin infection model, atopic treatment with the peptides resulted in significantly reduced yields of Candida from the infected skin areas. The antifungal activities of HLopt2 in vitro and in vivo suggest possible potential as a therapeutic agent against most Candida spp. and C. neoformans. The greatly improved antifungal effect of the lactam-modified HLBD1 indicates the importance of amphipathic helix formation for lethal activity.
由于医院感染患者中耐真菌菌株感染的数量不断增加，因此需要开发新的治疗这些感染的药物。天然存在的抗菌肽可能成为开发此类药物的模型。基于人乳铁蛋白（hLF）N 端 20-31 位氨基酸残基的改良肽序列（CFQWKRAMRKVR；HLopt2）以及双大小人乳铁肽类似物（氨基酸残基 16-40；HLBD1）被研究其体外和体内的抗真菌活性。通过体外试验，HLopt2 对新生隐球菌、白色念珠菌、克柔念珠菌、近平滑念珠菌和近平滑假丝酵母具有杀菌作用，浓度为 12.5-25 μg/mL，但对光滑念珠菌无效。HLopt2 的杀菌活性比 HLBD1 高 16 倍以上。通过诱导由内酰胺桥引起的一些螺旋形成或延长测定时间（从 2 小时延长至 20 小时），HLBD1 在杀菌活性方面几乎与 HLopt2 相当。HLopt2 迅速杀死白色念珠菌酵母细胞，同时伴随着细胞质和线粒体膜通透性以及酵母细胞表面形成深凹坑。在白色念珠菌皮肤感染的小鼠模型中，用肽进行特应性治疗可显著减少感染皮肤区域的念珠菌产量。HLopt2 的体外和体内抗真菌活性表明，它可能具有作为大多数念珠菌属和新型隐球菌的治疗剂的潜力。酰胺键修饰的 HLBD1 的抗真菌效果大大提高，表明两亲性螺旋形成对于致死活性很重要。
