Gene knockdown in HaCaT cells by small interfering RNAs entrapped in grapefruit-derived extracellular vesicles using a microfluidic device

Abstract

Small interfering RNAs (siRNAs) knockdown the expression of target genes by causing mRNA degradation and are a promising therapeutic modality. In clinical practice, lipid nanoparticles (LNPs) are used to deliver RNAs, such as siRNA and mRNA, into cells. However, these artificial nanoparticles are toxic and immunogenic. Thus, we focused on extracellular vesicles (EVs), natural drug delivery systems, for the delivery of nucleic acids. EVs deliver RNAs and proteins to specific tissues to regulate various physiological phenomena in vivo. Here, we propose a novel method for the preparation siRNAs encapsulated in EVs using a microfluidic device (MD). MDs can be used to generate nanoparticles, such as LNPs, by controlling flow rate to the device, but the loading of siRNAs into EVs using MDs has not been reported previously. In this study, we demonstrated a method for loading siRNAs into grapefruit-derived EVs (GEVs), which have gained attention in recent years for being plant-derived EVs developed using an MD. GEVs were collected from grapefruit juice using the one-step sucrose cushion method, and then GEVs-siRNA-GEVs were prepared using an MD device. The morphology of GEVs and siRNA-GEVs was observed using a cryogenic transmission electron microscope. Cellular uptake and intracellular trafficking of GEVs or siRNA-GEVs to human keratinocytes were evaluated by microscopy using HaCaT cells. The prepared siRNA-GEVs encapsulated 11% of siRNAs. Moreover, intracellular delivery of siRNA and gene suppression effects in HaCaT cells were achieved using these siRNA-GEVs. Our findings suggested that MDs can be used to prepare siRNA-EV formulations.

Engineered plant extracellular vesicles for natural delivery across physiological barriers

“…Itakura et al demonstrated the feasibility of a microfluidic fluid device (MD) to load siRNA into PDEVs by using an MD to embed siRNA to manipulate genes in human keratinocyte (HaCaT) cells without affecting cellular uptake. 36 Sonication treatment is the first choice for wrapping hydrophilic sex therapy drugs. The shear force induced by ultrasound causes deformation of the EV membrane, creating permeable pores on the membrane and making cargo loading possible.…”

“…Itakura et al demonstrated the feasibility of a microfluidic fluid device (MD) to load siRNA into PDEVs by using an MD to embed siRNA to manipulate genes in human keratinocyte (HaCaT) cells without affecting cellular uptake. 36…”