An Immunomodulatory Peptide Confers Protection in an Experimental Candidemia Murine Model

Antimicrob Agents Chemother. 2017 Jul 25;61(8):e02518-16. doi: 10.1128/AAC.02518-16. Print 2017 Aug.

Abstract

Fungal Candida species are commensals present in the mammalian skin and mucous membranes. Candida spp. are capable of breaching the epithelial barrier of immunocompromised patients with neutrophil and cell-mediated immune dysfunctions and can also disseminate to multiple organs through the bloodstream. Here we examined the action of innate defense regulator 1018 (IDR-1018), a 12-amino-acid-residue peptide derived from bovine bactenecin (Bac2A): IDR-1018 showed weak antifungal and antibiofilm activity against a Candida albicans laboratory strain (ATCC 10231) and a clinical isolate (CI) (MICs of 32 and 64 μg · ml-1, respectively), while 8-fold lower concentrations led to dissolution of the fungal cells from preformed biofilms. IDR-1018 at 128 μg · ml-1 was not hemolytic when tested against murine red blood cells and also has not shown a cytotoxic effect on murine monocyte RAW 264.7 and primary murine macrophage cells at the tested concentrations. IDR-1018 modulated the cytokine profile during challenge of murine bone marrow-derived macrophages with heat-killed C. albicans (HKCA) antigens by increasing monocyte chemoattractant protein 1 (MCP-1) and interleukin-10 (IL-10) levels, while suppressing tumor necrosis factor alpha (TNF-α), IL-1β, IL-6, and IL-12 levels. Mice treated with IDR-1018 at 10 mg · kg-1 of body weight had an increased survival rate in the candidemia model compared with phosphate-buffered saline (PBS)-treated mice, together with a diminished kidney fungal burden. Thus, IDR-1018 was able to protect against murine experimental candidemia and has the potential as an adjunctive therapy.

Keywords: Candida albicans; IDR-1018 peptide; antifungals; host-directed therapy; immunomodulatory effects; murine experimental candidemia.

MeSH terms

  • Animals
  • Antifungal Agents / therapeutic use*
  • Antimicrobial Cationic Peptides / therapeutic use*
  • Biofilms / drug effects*
  • Candida albicans / drug effects*
  • Candida albicans / immunology
  • Candida albicans / isolation & purification
  • Candidemia / drug therapy*
  • Candidemia / prevention & control*
  • Cell Line
  • Chemokine CCL2 / immunology
  • Disease Models, Animal
  • Immunologic Factors / therapeutic use*
  • Interleukin-10 / immunology
  • Interleukin-12 Subunit p35 / metabolism
  • Interleukin-1beta / metabolism
  • Interleukin-6 / metabolism
  • Macrophages / drug effects
  • Mice
  • Microbial Sensitivity Tests
  • RAW 264.7 Cells
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • Antifungal Agents
  • Antimicrobial Cationic Peptides
  • Ccl2 protein, mouse
  • Chemokine CCL2
  • IL10 protein, mouse
  • IL1B protein, mouse
  • Il12a protein, mouse
  • Immunologic Factors
  • Interleukin-12 Subunit p35
  • Interleukin-1beta
  • Interleukin-6
  • Tumor Necrosis Factor-alpha
  • innate defense regulating peptide 1018
  • interleukin-6, mouse
  • Interleukin-10

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