OBJECTIVE To prepare self-assembled antimicrobial peptide LL-37 nanomicelles by genetic engineering technology and evaluate the therapeutic potential of this novel peptide in sepsis induced acute lung injury.
METHODS Using genetic engineering technology to construct LL-37-ELPs fusion protein expression vector, taking advantage of the reversible phase transition property of ELPs fusion protein, the fusion protein containing ELPs tag was specifically isolated from the supernatant of soluble protein expressed in E. coli by several inverse transition cycle. Transmission electron microscopy and dynamic light scattering were used to characterize antimicrobial peptide LL-37 nanomicelles. Subsequently, a mouse model of sepsis was established, and drugs were injected intravenously every day for 5 d after surgery. Survival rates within 5 d were counted. Six days after surgery, mice in each group were sacrificed peacefully. HE staining was used to observe the pathological changes of lung tissue, and the lung injury score was evaluated. Lung endothelial cell permeability was assessed by Evans Blue staining, and lung wet weight ratio was calculated. ELISA was used to detect the expression of tumor necrosis factor-α, IL-1β and IL-6 in lung tissue. Neutrophil aggregation was detected by flow cytometry.
RESULTS The LL-37 antimicrobial peptide nanomicelles were successfully prepared, which were uniform in size with a diameter of 80−100 nm and good stability. In septic mice, it could effectively reduce sepsis-induced lung injury, reduce lung inflammation, and improve the survival rate of septic mice.
CONCLUSION Antimicrobial peptide LL-37 nanomicelles are successfully prepared, which have good application prospects in sepsis-induced acute lung injury.
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