Protective effect and mechanism of nanoantimicrobial peptide ND-C14 against Streptococcus pneumoniae infection

• DOI: 10.5847/wjem.j.1920-8642.2024.014
• Publication Date: 2024-01-02T01:04:42Z
• Authors: Yangyang Guo; Yaqi Sun; Hongxia Wu; Jian Lu; Yuan Lin; Jiaqing Zhu; Meihong Lai; Meiqi Zhang; Jun Wang; Jungang Zheng
• Keywords: Propidium iodide

BACKGROUND: Streptococcus pneumoniae (S. pneumoniae) is a common pathogen that causes bacterial pneumonia.However, with increasing resistance, there an urgent need to develop new drugs treat S. infections.Nanodefensin 14-carbon saturated fatty acid (ND-C14) novel nanoantimicrobial peptide designed by modifying myristic at the C-terminus of human α-defensin 5 (HD5) via amide bond.However, it unclear whether ND-C14 effective against lung infections caused pneumoniae. METHODS:In vitro, three groups were established, including control group, and HD5 treatment groups.A virtual colony-count assay was used evaluate antibacterial activity pneumoniae.The morphological changes treated or observed scanning electron microscopy.In vivo, mice divided into sham, vehicle, groups.Mice in sham group 25 μL phosphate-buffered saline (PBS).Mice vehicle intratracheal instillation suspension 2×10 8 CFU/mL (total count: 5×10 6 CFU), then given PBS intratracheally injected (including 20 μg 50 μg), respectively.Survival rates evaluated groups.Bacterial burden blood bronchoalveolar lavage fl uid counted.The histology assessed.A propidium iodide uptake clarify destructive eff ect RESULTS:Compared HD5, had better bactericidal because its stronger ability destroy membrane structure vitro.In significantly delayed death time improved survival rate infected pneumoniae.ND-C14 reduced tissue injury.Moreover, permeation on pneumoniae, increased concentration. CONCLUSION:The may improve ects both vitro vivo.