Nose-to-brain delivery of enveloped RNA - cell permeating peptide nanocomplexes for the treatment of neurodegenerative diseases

Abstract

Direct nose-to-brain (N-to-B) delivery enables the rapid transport of drugs to the brain, while minimizing systemic exposure. The objective of this work was to engineer a nanocarrier intended to enhance N-to-B delivery of RNA and to explore its potential utility for the treatment of neurological disorders. Our approach involved the formation of electrostatically driven nanocomplexes between a hydrophobic derivative of octaarginine (r8), chemically conjugated with lauric acid (C12), and the RNA of interest. Subsequently, these cationic nanocomplexes were enveloped (enveloped nanocomplexes, ENCPs) with different protective polymers, i.e. polyethyleneglycol -polyglutamic acid (PEG-PGA) or hyaluronic acid (HA), intended to enhance their stability and mucodiffusion across the olfactory nasal mucosa. These rationally designed ENCPs were produced in bulk format and also using a microfluidics-based technique. This technique enabled the production of a scalable nanoformulation, exhibiting; (i) a unimodal size distribution with a tunable mean size, (ii) the capacity to highly associate (100%) and protect RNA from degradation, (iii) the ability to preserve its physicochemical properties in biorelevant media and prevent the premature RNA release. Moreover, in vitro cell culture studies showed the capacity of ENCPs to interact and be efficiently taken-up by CHO cells. Finally, in vivo experiments in a mouse model of Alzheimer's disease provided evidence of a statistically significant increase of a potentially therapeutic miRNA mimic in the hippocampus area and its further effect on two mRNA targets, following its intranasal administration. Overall, these findings stress the value of the rational design of nanocarriers towards overcoming the biological barriers associated to N-to-B RNA delivery and reveal their potential value as therapeutic strategies in Alzheimer's disease.

Arginine-Based Poly(I:C)-Loaded Nanocomplexes for the Polarization of Macrophages Toward M1-Antitumoral Effectors

“…At the same time, the formulation of polynucleotides within nanosystems is able to protect them from degradation (45). Bearing all this in mind, we have formulated poly(I:C) in the form of nanocomplexes enveloped with two biodegradable and stabilizing polymers (PEG-PGA and HA), known to facilitate the arrival to the tumor site (40,(46)(47)(48)(49)(50)(51)(52)(53). Once in the tumor, a preferential uptake of the nanosystems by macrophages could be anticipated due to their high phagocytic capacity, as already described for both, targeted and non-targeted nanosystems (15,54,55).…”

“…As the first step in the development of a poly(I:C)-loaded nanoformulation and, based on a nanosystem recently reported by our group showing the capacity of modified octaarginine to complex polynucleotides (40), different positively-charged arginine-rich polymers were selected for poly(I:C) complexation. Oligo-arginines have been extensively employed for the delivery of different nucleic acids due to their CPP nature, which increases their uptake and, as a result, improves their therapeutic performance (37,40,56). For this purpose, and taking as a reference our previous work (40) and additional reports (57), two oligopeptides were selected: octaarginine (r8) and a hydrophobically-modified r8, that contains a laurate chain (C12r8).…”

Recent Developments in Microfluidic Technologies for Central Nervous System Targeted Studies

“…This, in turn, led to a decrease in the expression levels of GATA2 and Rb1 proteins, which play a role in cell cycle and are upregulated in AD. Overall, the findings suggest that the RNA nanocarriers developed by Samaridou et al are a promising therapeutic strategy for AD [118].…”

“…MicroRNA interference (miRNA) therapy holds great potential to treat many disorders, including NDs. Samaridou et al [118] engineered RNA-loaded cationic nanocomplexes for direct nose-to-brain delivery. The formation of the nanocomplexes was based on electrostatic interactions between a modified octaarginine (C12-r8) and the RNA molecules.…”

Status update in the use of cell-penetrating peptides for the delivery of macromolecular therapeutics

“…The authors quantified miRNA levels in brain and concluded that their delivery system provides trans-BBB delivery. Additionally, molecular confirmation for the miRNA activity was provided, as the expression of two predicted mRNA targets in different brain areas were affected by their treatment [39]. Future reports should show if such approach allows also functional effects from the modified genes, as well as clinical effects and will show how much potential it holds for the neurological disorders.…”