Characterisation and Protein Composition Analysis of Cucumis sativus L. Plant derived Nanovesicles

Abstract

Background: It has been discovered that the cargo of plant-derived nanovesicles (PDNVs) contains a large amount of protein [1,2]. Due to the specific structure of PDNVs, their cargo is encapsulated and protected from enzymes, allowing more potent effects than crude extracts. Due to all these characteristics, PDNVs have recently gained much attention as promising active ingredients to produce cosmetics, medicines, or food supplements. However, the protein content of PDNVs is not well-studied yet, and this prevents PDVN practical applicability. Results of preliminary studies show that cucumber PDNVs can increase skin regeneration, but to define the mechanism of the action, the composition of PDNV cargo needs to be determined. Aim: To isolate PDNVs from cucumber fruits and leaves, characterise them, and determine the composition of proteins. Methods: Isolation of PDNVs by polymeric precipitation method; Bradford method; Nanoparticle Tracking Analysis; Gene ontology (GO) analysis by g:Profiler. Results: PDNVs were isolated from cucumber fruits and leaves. In both samples, the peak of the particle size values distribution curve was around 100 nm. The size distribution profile showed an orderly Gaussian pattern in the leaf PDNVs sample, while it was more heterogeneous in the fruit PDNVs sample. A larger number of particles per 1 mg of protein was observed in fruit PDNVs than in leaf PDNVs. Approximately 500 different proteins were identified in the leaf sample, while in fruit PDNVs, only 150 proteins were found. There were 117 proteins commonly expressed in both samples. GO analysis revealed that both samples of PDNVs were enriched with intracellular and cytoplasm-origin proteins. Proteins of extracellular origin were found in leaf PNDVs. GO terms of molecular functions indicate that proteins are involved in catalytic processes, and GO terms of biological processes show that proteins participate in metabolic processes. Conclusions: In summary, most proteins detected in cucumber fruit and leaf PDNVs are involved in catalytic and metabolic processes. These results are essential for further investigating PDNVs’ biological properties on targeted cell models.