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Analogues of peptide SMAP-29 with comparable antimicrobial potency and reduced cytotoxicity

Raymond M Dawson1, Chun-Qiang Liu

  • 1DSTO Melbourne, 506 Lorimer Street, Fishermans Bend, VIC 3207, Australia. ray.dawson@dsto.defence.gov.au

International Journal of Antimicrobial Agents
|March 8, 2011
PubMed

Insights

Researchers modified sheep myeloid antimicrobial peptide-29 (SMAP-29) to reduce toxicity. Two new analogues show potent antibacterial effects against Bacillus anthracis with significantly lower toxicity, enhancing therapeutic potential.

Area of Science:

  • Biochemistry
  • Peptide Science
  • Antimicrobial Research

Background:

  • Sheep myeloid antimicrobial peptide-29 (SMAP-29) exhibits strong antibacterial properties.
  • High cytotoxicity to human red blood cells (hRBCs) and human embryonic kidney (HEK) cells limits SMAP-29's therapeutic applications.
  • Developing antimicrobial peptides with reduced host cell toxicity is a critical challenge.

Purpose of the Study:

  • To design and evaluate SMAP-29 analogues with reduced haemolytic activity while retaining potent antibacterial efficacy.
  • To assess the cytotoxicity and antimicrobial activity of novel and existing peptide analogues.
  • To identify analogues with an improved therapeutic index compared to native SMAP-29.

Main Methods:

  • Amino acid substitutions were introduced into SMAP-29 to create novel analogues.
  • Cytotoxicity was evaluated using human red blood cells (hRBCs) and human embryonic kidney (HEK) cells.
  • Antimicrobial efficacy was tested against Gram-positive bacteria (Bacillus anthracis, Bacillus globigii) and Gram-negative bacteria (Escherichia coli, Burkholderia thailandensis).

Main Results:

  • Literature-reported analogues showed low antibacterial and haemolytic activity.
  • Two newly designed SMAP-29 analogues demonstrated comparable antibacterial efficacy against Bacillus anthracis as native SMAP-29.
  • These two analogues exhibited significantly reduced haemolytic activity, resulting in a 2.3-2.6 fold enhancement in therapeutic index.

Conclusions:

  • Amino acid modification can effectively reduce the cytotoxicity of SMAP-29.
  • Novel SMAP-29 analogues offer a promising alternative for treating Gram-positive bacterial infections with improved safety profiles.
  • Further research into these modified peptides could lead to new antimicrobial therapeutics.

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