Long-Lasting Stable Expression of Human LL-37 Antimicrobial Peptide in Transgenic Barley Plants

Abstract

Antimicrobial peptides play a crucial role in the innate immune system of multicellular organisms. LL-37 is the only known member of the human cathelicidin family. As well as possessing antibacterial properties, it is actively involved in various physiological responses in eukaryotic cells. Accordingly, there is considerable interest in large-scale, low-cost, and microbial endotoxin-free production of LL-37 recombinant peptides for pharmaceutical applications. As a heterologous expression biofactory, we have previously obtained homologous barley (Hordeum vulgare L.) as an attractive vehicle for producing recombinant human LL-37 in the grain storage compartment, endosperm. The long-term stability of expression and inheritance of transgenes is necessary for the successful commercialization of recombinant proteins. Here, we report the stable inheritance and expression of the LL-37 gene in barley after six generations, including two consecutive seasons of experimental field cultivation. The transgenic plants showed normal growth and remained fertile. Based on the bacteria viability test, the produced peptide LL-37 retained high antibacterial activity.

BsR1, a broad-spectrum antibacterial peptide with potential for plant protection

“…Lastly, we suggest exploring the expression of antimicrobial peptides in plants ( 64 ). For instance, expressing cecropin A in rice can enhance resistance to the rice blast fungus Magnaporthe grisea ( 65 ), while introducing human LL-37 into transgenic barley can confer long-term stability ( 66 ). Other examples include the incorporation of the pharmaceutically active polypeptide SMAP-29 ( 67 ) and the transformation of citrus with sarcotoxin IA , rendering them less susceptible to Candidatus Liberibacter asiaticus (CLas) ( 68 ).…”

Advances in the use of plants as potential biofactories in the production of antimicrobial peptides

“…[ 11 ] In another study, the cathelicidin LL‐37gene was used for stable transformation, and protein production in grain storage compartment, endosperm, and the results revealing a promising template for the development of other antibiotics. [ 72 ] The seeds of transgenic barley were able to accumulate a high level of recombinant LL‐37. [ 36 ] Bundó et al .…”

“…These grains are capable of storing recombinant molecules, maintaining activity even in a dormant stage, and can preserve the molecule's stability for years. [71][72][73] Naturally, seeds can accumulate AMPs, and this storage organ can also be used for transient expression for synthetic peptide production and high antimicrobial activity. As discussed earlier, synthetic AMP design, based on natural plant-source peptides, has been increasingly explored.…”

“…[11] In another study, the cathelicidin LL-37gene was used for stable trans- F I G U R E 2 Simplified illustration for plant transformation methods, to tissue-specific endosperm, and the results revealing a promising template for the development of other antibiotics. [72] The seeds of transgenic barley were able to accumulate a high level of recombinant LL-37. [36] Bund o et al [62] show potent and selective activity against fungal pathogen of recombinant AMPs produced in rice seeds.…”

Editorial for Special Issue “Alternatives to Antibiotics: Bacteriocins and Antimicrobial Peptides”

“…One of the biggest barriers in the wide-scale use of AMPs is also addressed in this Special Issue by Mirzaee and collaborators [ 10 ]: costs of production. There is no denying that AMPs are the future, but large-scale production at a low cost is still not easily achieved.…”