Wound healing activity and mechanisms of action of an antibacterial protein from the venom of the eastern diamondback rattlesnake (Crotalus adamanteus)

PLoS One. 2014 Feb 14;9(2):e80199. doi: 10.1371/journal.pone.0080199. eCollection 2014.

Abstract

Basic phospholipase A2 was identified from the venom of the eastern diamondback rattlesnake. The Crotalus adamanteus toxin-II (CaTx-II) induced bactericidal effects (7.8 µg/ml) on Staphylococcus aureus, while on Burkholderia pseudomallei (KHW), and Enterobacter aerogenes were killed at 15.6 µg/ml. CaTx-II caused pore formation and membrane damaging effects on the bacterial cell wall. CaTx-II was not cytotoxic on lung (MRC-5), skin fibroblast (HEPK) cells and in mice. CaTx-II-treated mice showed significant wound closure and complete healing by 16 days as compared to untreated controls (**P<0.01). Histological examination revealed enhanced collagen synthesis and neovascularization after treatment with CaTx-II versus 2% Fusidic Acid ointment (FAO) treated controls. Measurement of tissue cytokines revealed that interleukin-1 beta (IL-1β) expression in CaTx-II treated mice was significantly suppressed versus untreated controls. In contrast, cytokines involved in wound healing and cell migration i.e., monocyte chemotactic protein-1 (MCP-1), fibroblast growth factor-basic (FGF-b), chemokine (KC), granulocyte-macrophage colony-stimulating factor (GM-CSF) were significantly enhanced in CaTx-II treated mice, but not in the controls. CaTx-II also modulated nuclear factor-kappa B (NF-κB) activation during skin wound healing. The CaTx-II protein highlights distinct snake proteins as a potential source of novel antimicrobial agents with significant therapeutic application for bacterial skin infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / isolation & purification
  • Anti-Bacterial Agents / pharmacology*
  • Anti-Bacterial Agents / toxicity
  • Bacteria / drug effects
  • Bacteria / growth & development
  • Bacteria / ultrastructure
  • Cell Death / drug effects
  • Cell Line
  • Cell Membrane / drug effects
  • Cell Membrane / metabolism
  • Cell Survival / drug effects
  • Collagen / metabolism
  • Colony Count, Microbial
  • Crotalid Venoms / chemistry
  • Crotalid Venoms / isolation & purification
  • Crotalid Venoms / pharmacology*
  • Crotalid Venoms / toxicity
  • Crotalus / metabolism*
  • Cytokines / metabolism
  • Epithelium / drug effects
  • Epithelium / pathology
  • Humans
  • Inflammation Mediators / metabolism
  • L-Lactate Dehydrogenase / metabolism
  • Male
  • Mice
  • Microbial Sensitivity Tests
  • NF-kappa B / metabolism
  • Sequence Analysis, Protein
  • Skin / drug effects
  • Skin / pathology
  • Wound Healing / drug effects*

Substances

  • Anti-Bacterial Agents
  • Crotalid Venoms
  • Cytokines
  • Inflammation Mediators
  • NF-kappa B
  • Collagen
  • L-Lactate Dehydrogenase

Grant support

The authors are thankful to the Economic Development Board (EDB), Singapore, for financial support by Proof of Concept (Grant No: R-181-000-110-144). This work was also supported in part by a grant from MOE Tier I to Dr. Gautam Sethi. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.