E-Book

E-Book 3rd Congress

  • ANTIMICROBIAL PEPTIDES IN BIOMEDICAL APPLICATIONS
  • Dr. Issa Layali,1 Zahra Toolabie,2 Negin Mansouri,3 Melika Chalook,4,*
    1. Department of Biochemistry and           Biophysics, faculty of Advanced Sciences and Technology, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran               
    2. Bachelor’s student, Microbiology Group, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
    3. Tehran. Shariati street. Khaghani street , Danesh  dead end, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
    4. Bachelor’s student, Microbiology Group, Faculty of Advanced Science and Technology, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran


  • Introduction: According to a 2014 report by WHO, antimicrobial resistance is a growing challenge that must be addressed. This resistance poses a significant problem for the treatment of diseases and infections and is typically caused by mutation, gene transfer, long-term or improper use of antimicrobials, survival of microbes after antimicrobial consumption, and the presence of antimicrobials in agricultural feeds, as well as hospital and medical device-induced biofilm infections. These issues affect millions of lives and require urgent innovative preventive approaches. One potential solution to these problems is antimicrobial peptides (AMPs), which are widely present in the environment. The biomedical field has a high demand for AMPs, which is an emerging topic involving both natural and synthetic pathways and some of which are currently undergoing clinical testing for approval. AMPs were discovered in 1939 by Rene Dubos isolated an antimicrobial agent named gramicidin from a soil Bacillus strain which protected mice from pneumococcal infection. Peptides can be categorized in multiple ways based on activity, mechanism of action, or structure and sequence. AMPs interact with bacterial cell membranes, impacting construction of the membrane, leading to cell death. AMPs can recruit and activate immune cells, controlling inflammation and increasing cell killing. AMPs also produce a variety of immune responses like activation, attraction, and differentiation of white blood cells. Immune cells also produce AMPs and can be the first line of defense against invading microbes. AMPs are mostly amphipathic, cationic peptides that display antimicrobial activity against bacteria, fungi and viruses, for example in bacteria they interact with specific constituents of the bacterial cell envelope resulting in depolarization, destabilization or disruption of the bacterial plasma membrane leading to bacterial cell death. Naturally occurring AMPs have been used as design templates for synthetic AMPs, some of which have reached the stage of clinical trials like the he synthetic peptide IDR-1018 prevented biofilm formation by S.aureus and other species by blocking ppGpp which is a signal molecule in biofilm formation.
  • Methods: Currently the most commonly used method of obtaining AMPs is chemical synthesis. In clinical trials and commercial markets, large quantities of AMPs are needed to fulfil basic scientific study requirements. Isolation from natural sources and chemical synthesis are not costeffective, For cost-effective production of large peptides biological systems such as bacteria and yeast are required, Escherichia coli and yeast are two major systems used to produce recombinant antimicrobial peptides. Summarising over many years scientists have developed methods of obtaining AMPs not only through their direct isolation from organisms but also chemical methods for the synthesis of these peptides and finally more efficient methods of obtaining recombinant AMPs by genetic engineering.
  • Results: AMPs isolated from vertebrates are studied due to their potency against a wide range of microorganism. The most commonly found and highly investigated antimicrobial peptides are Defensins and Cathelicidins. Defensin is positively charged antimicrobial peptide composed of 29–34 amino acids in a sheet structure and Cathelicidin is a multifunctional peptide that has conserved pro-peptide sequences and is identified as an N terminal signal peptide. Crohn’s disease can be eliminated by inducing Defensins. In patients suffering from periodontitis, Defensins play a critical role in bone repairmen and also they have the capability to suppress inflammatory cytokines and is also used in therapy for the herpes simplex virus. The potency of Cathelicidins LL-37 was examined on human MDMs and THP-1 cells, which were infected with Mycobacterium tuberculosis these cells were infected with the M.tuberculosis for four hours, followed by treatment with 1 g/m of LL 37 for 24 h, it was concluded that LL-37 mediates the activation of autophagy via the P2RX7 receptor and inhibits the growth of Mycobacterium tuberculosis. In another study the Cathelicidins peptides have shown antifungal activity against Fusarium, Aspergillus, Cryptococcus, and Candida.
  • Conclusion: AMPs can be used as new therapeutics, enhancing antimicrobial treatment and reducing resistance. Despite challenges associated with the of AMPs including stability and half-life issues, the market is expected to benefit from growing interest in innovative therapeutics containing antimicrobial peptides for rare diseases.
  • Keywords: amps, antimicrobial, peptides