1. Academic Validation
  2. Antimicrobial peptide LL-37 and IDR-1 ameliorate MRSA pneumonia in vivo

Antimicrobial peptide LL-37 and IDR-1 ameliorate MRSA pneumonia in vivo

  • Cell Physiol Biochem. 2013;32(3):614-23. doi: 10.1159/000354465.
Man Hou 1 Nengwei Zhang Jingjing Yang Xiangyu Meng Ruan Yang Jian Li Tieying Sun
Affiliations

Affiliation

  • 1 Peking University Fifth School of Clinical Medicine, Beijing Hospital of the Ministry of Health, Beijing, China.
Abstract

Background: The only human cathelicidin, LL-37, and the innate defense regulator peptide IDR-1, which have been proven to have antimicrobial activity, represent essential elements of immunity. Our previous study showed that the peptide LL-37 was protective in vitro to attenuate LTA-induced inflammatory effects. Methicillin-resistant staphylococcus aureus (MRSA) causes a multitude of serious and sometimes life-threatening diseases around the globe. However, the effect of LL-37 and IDR-1 in MRSA-induced pneumonia is unknown. In the present study, we explored the potential of LL-37 and IDR-1 in ameliorating MRSA-induced pneumonia in vivo.

Methods: C57BL/6 mice were randomly divided into four groups and perfused intratracheally with PBS, peptide, MRSA and MRSA plus peptide, respectively. Pulmonary tissue pathology, ELISA and quantitative RT-PCR were employed. The relative signal pathways were further explored by western blot analysis.

Results: Pathological analysis of the lung tissue sections demonstrated that, when compared with the MRSA-treated group, both the LL-37 and IDR-1 could ameliorate the MRSA-induced pneumonia. The phosphorylation of JNK and Akt were markedly decreased in the peptide plus MRSA-treated group compared with the MRSA-treated group. Furthermore, both of them also reduced TNF-α and IL-6 production in the bronchoalveolar lavage fluid (BALF) and serum in vivo.

Conclusion: We report the first evidence of Peptides inhibiting inflammation, decreasing the release of inflammatory cytokines and restoring pulmonary function in vivo. The antimicrobial peptide LL-37 and IDR-1 could ameliorate MRSA-induced pneumonia by exerting an anti-inflammatory property and attenuating pro-inflammatory cytokine release, thus providing support for the hypothesis that both innate and synthetic Peptides could protect against MRSA in vivo.

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