Enrika Celitan has defended her thesis entitled "Evaluation of the properties and delivery potential of Saccharomyces cerevisiae L-BC-1 virus-derived nanoparticles" for the degree of Doctor of Science in Biochemistry.
Scientific supervisor: Prof. Dr. Saulius Serva (Vilnius University, Natural Sciences, Biochemistry).
Composition of the Dissertation Defense Board: Chairperson - Prof. Dr. Eglė Lastauskienė (Vilnius University, Natural Sciences, Biology); Dr. Rasa Petraitytė-Burneikienė (Vilnius University, Natural Sciences, Biochemistry); Dr. Dukas Jurėnas (Université Libre de Bruxelles, Belgium, Natural Sciences, Biochemistry); Dr. Mindaugas Zaremba (Vilnius University, Natural Sciences, Biochemistry); Dr. Živilė Strazdaitė-Žielienė (Nature Research Centre, Natural Sciences, Biochemistry).
Virus-like particles (VLPs) are nanostructures composed of self-assembling viral proteins. They mimic the structure of native viruses but are non-infectious due to the absence of genetic material. VLPs are increasingly used in developing various molecular delivery systems thanks to their safety and broad functionalization potential.
In this study, the VLP synthesis was based on the L-BC-1 virus, found in Saccharomyces cerevisiae and characterized by the absence of an extracellular phase. Previous research has focused on the structural properties and possible functions of yeast viruses within the yeast cell. Here, the stability and encapsulation potential of L-BC-1-derived nanoparticles were evaluated to explore their application in delivery system development.
The recombinant capsid protein Gag from the L-BC-1 virus was successfully synthesized in both Escherichia coli and S. cerevisiae, forming symmetric, spherical particles approximately 40 nm in diameter. The stability of Gag-derived VLPs was analyzed using dynamic light scattering (DLS), transmission electron microscopy (TEM), and thermal shift assays (TSA). The particles maintained a stable size for up to 24 weeks under various conditions. Structural degradation was observed under high temperatures, alkaline conditions, or upon exposure to urea. Compared to yeast-derived particles, those synthesized in bacteria were more sensitive to environmental stressors.
The small antimicrobial peptide nisin Z was encapsulated using passive diffusion into the VLPs, endowing the particles with antibacterial activity. Additionally, a high red fluorescent protein mCherry concentration was encapsulated using a gene fusion strategy, demonstrating successful VLP uptake by mammalian cells. Notably, VLPs produced in bacteria exhibited cytotoxicity toward mammalian cells, while yeast-derived particles did not.
These findings provide valuable insights into the properties of the L-BC-1 virus and support its potential application in the development of molecular delivery systems.
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