Characterization and Uptake of Strawberry-Derived Exosome-Like Nanovesicles by Human Aortic Endothelial Cells

Abstract

Abstract Objectives To characterize strawberry (SB)-derived exosome-like nanovesicles (ELNs), assess the total phenolic content, total flavonoid content, and total antioxidant capacity as well as its uptake by human aortic endothelial cells (HAECs). Methods SB ELNs were extracted using differential centrifugation. After final ultracentrifugation at 100,000 × g for 1 h, pellets were collected and washed in PBS. Characterization was performed using dynamic light scattering measurements. Total phenolic content (TPC) and flavonoid content (TFC) were determined using Folin-Ciocalteu and aluminum chloride, respectively. Antioxidant capacity was determined using the Trolox equivalent antioxidant capacity (TEAC) and ferric reducing ability of plasma (FRAP) assay while free radical scavenging power was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay. Cell viability and uptake were assessed in HAECs. Cell viability was measured after 24-h incubation with SB ELNs using MTT reagent. Cell uptake was measured after 12-h incubation with 100 μg/mL coumarin-6 (C-6) labelled SB ELNs. Fluorescent microscopy and flow cytometry were used to detect cellular uptake of C-6 labelled SB ELNs on a LSR II. Results SB ELNs were sized at 119.4 ± 28.3 nm (PDI = 0.29 ± 0.06). TPC and TFC of SB ELNs were 158.9 ± 22.6 μmol GAE/L and 5.1 ± 0.4 μg QE/mL, respectively. Antioxidant capacity of SB ELNs was 211.38 ± 6.3 μmol TE/L and 118.0 ± 7.6 μmol Fe2+/L by TEAC and FRAP, respectively. DPPH radical scavenging capacity was 181.3 ± 2.5 μmol TE/L in SB ELNs. No cytotoxic effects were observed for SB ELNs in HAECs. Uptake of SB ELNs by HAECs was 15.3% higher compared to baseline levels. Conclusions We report, for the first time, the presence of phenolics and flavonoids in the cargo of SB ELNs, SB ELNs antioxidant capacity, and demonstrate their uptake by HAECs. Taken together, these findings support the need to further characterize and explore the antioxidant potential of SB ELNs in vitro and in vivo. Funding Sources None.