J. Atienza-Garriga

University of Barcelona, Spain

Title: ANALYSIS OF THE PROTECTION OF PROTEIN-ONLY NANOPARTICLES CONTAINING ANTIMICROBIAL PEPTIDES WITH LIPOSOMES AND MICELLES

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Biography

Jan Atienza-Garriga graduated in biotechnology and obtained his Master's in Food Biotechnology at the University of Girona (Spain). He is currently studying for a PhD thesis directed by Prof. Neus Ferrer-Miralles at the Nanobiotechnology group headed by Prof. Antonio Villaverde at the Institute of Biotechnology and Biomedicine (IBB) from the Autonomous University of Barcelona (Spain), working on the use of antimicrobial peptides and multivalent protein complexes to be administered through lipid structures (e.g. liposomes) and micelles.

Abstract

Antimicrobial peptides (AMPs) are secreted factors involved in the innate and acquired immune system, providing potent efficacy against bacteria, fungi, and viruses. A small peptide like an AMP is difficult to be recombinantly produced at large scale, but their fusion to a scaffold protein is an approach used to overcome this limitation. A modular recombinant protein derived from this process can be efficiently produced and purified.

In this study, AMPs fused to His-tagged eGFP were used to study their solubility pattern at different pHs and their loading capacity, followed by their stability alone or combined within liposomes and polymeric micelles, with the goal of obtaining novel formulations that can protect protein nanoparticles from protease activity when administered intranasally.

Among the results obtained, it was observed that the pH of the buffer in which the AMP protein NP is located clearly affected the ability to reduce bacteria viability. It was also shown that the AMP proteins produced nanoparticles (NPs) of a similar size. Moreover, it was observed that LUVs were able to encapsulate protein NPs of the expected size, and especially LUVs composed by 100 % Phosphatidylcholine did not protect the encapsulated protein against mucus proteases. Kinetic analysis with trypsin demonstrates proteolytic degradation of the encapsulated protein. Finally, it was determined that polymeric micelles with covalent bonds had a protective capacity for these protein NPs.

In summary, the results obtained in this study showed that the stability of the liposomes was observed to be trypsin-dependent Interestingly, protein NPs covalently bound to micelles were protected from proteolysis after incubation with bovine mucus. Further experiments are needed to evaluate the efficacy of these complexes in the delivery of protein NPs with antimicrobial potential in intranasal administrations to fight against respiratory infections.