Wolfmeier Heidi, Wardell Samuel J T, Liu Leo T, Falsafi Reza, Draeger Annette, Babiychuk Eduard B, Pletzer Daniel, Hancock Robert E W
Department of Microbiology and Immunology, Centre for Microbial Diseases and Immunity Research, University of British Columbia, Vancouver, BC, Canada.
Institute of Anatomy and Cell Biology, Paracelsus Medical University, Salzburg, Austria.
Front Microbiol. 2022 Mar 18;13:867449. doi: 10.3389/fmicb.2022.867449. eCollection 2022.
Engineered liposomes composed of the naturally occurring lipids sphingomyelin (Sm) and cholesterol (Ch) have been demonstrated to efficiently neutralize toxins secreted by Gram-positive bacteria such as and . Here, we hypothesized that liposomes are capable of neutralizing cytolytic virulence factors secreted by the Gram-negative pathogen . We used the highly virulent cystic fibrosis Liverpool Epidemic Strain LESB58 and showed that sphingomyelin (Sm) and a combination of sphingomyelin with cholesterol (Ch:Sm; 66 mol/% Ch and 34 mol/% Sm) liposomes reduced lysis of human bronchial and red blood cells upon challenge with the secretome. Mass spectrometry of liposome-sequestered proteins identified the virulence-promoting hemolytic phospholipase C (PlcH) as having been neutralized. supernatants incubated with liposomes demonstrated reduced PlcH activity as assessed by the -nitrophenylphosphorylcholine (NPPC) assay. Testing the efficacy of the liposomes in a murine cutaneous abscess model revealed that Sm and Ch:Sm, as single dose treatments, attenuated abscesses by >30%, demonstrating a similar effect to that of a mutant lacking in this infection model. Thus, sphingomyelin-containing liposome therapy offers an interesting approach to treat and reduce virulence of complex infections caused by and potentially other Gram-negative pathogens expressing .
由天然存在的脂质鞘磷脂（Sm）和胆固醇（Ch）组成的工程化脂质体已被证明能有效中和革兰氏阳性菌分泌的毒素，如……。在此，我们假设脂质体能够中和革兰氏阴性病原体分泌的细胞溶解性毒力因子。我们使用了高毒力的囊性纤维化利物浦流行菌株LESB58，结果表明，鞘磷脂（Sm）以及鞘磷脂与胆固醇的组合（Ch:Sm；66摩尔/% Ch和34摩尔/% Sm）脂质体在用该菌分泌组攻击后可减少人支气管细胞和红细胞的裂解。对脂质体隔离的该菌蛋白质进行质谱分析，确定毒力促进因子溶血磷脂酶C（PlcH）已被中和。通过对硝基苯基磷酰胆碱（NPPC）测定评估，与脂质体一起孵育的该菌培养上清液显示出降低的PlcH活性。在小鼠皮肤脓肿模型中测试脂质体的疗效，结果显示，作为单剂量治疗，Sm和Ch:Sm可使脓肿减轻>30%，在该感染模型中显示出与缺乏该菌的突变体类似的效果。因此，含鞘磷脂的脂质体疗法为治疗和降低由该菌以及可能表达该菌的其他革兰氏阴性病原体引起的复杂感染的毒力提供了一种有趣的方法。
