Cooperative Assembly of Self-Adjusting α-Helical Coiled Coils along the Length of an mRNA Chain to Form a Thermodynamically Stable Nanotube Carrier

Supramolecular oral delivery technologies for polypeptide-based drugs

Oral supramolecular drug delivery systems (SDDSs) have shown promising potential, along with a rapid increase in the development of polypeptide-based drugs. Biofriendly, biocompatible, and multistimulation-responsive SDDSs achieve their unique deliverability via noncovalent bonds, which can encapsulate drugs and release them at the target site along the oral tract. In this review, we analyze the oral tract from an anatomical perspective and explain the potential physical, microenvironmental, and systematic barriers, as well as the properties of drug delivery. After understanding the specific environment at different oral sites, the application of SDDSs to the mouth, stomach, small intestine, and cell targeting is summarized. Finally, this review summarizes the application of SDDSs for the successful delivery of drugs and describes how to overcome the barriers of SDDSs in drug delivery using a more biofriendly approach.

Folding of mRNA-DNA Origami for Controlled Translation and Viral Vector Packaging

mRNA is an important molecule in vaccine development and treatment of genetic disorders. Its capability to hybridize with DNA oligonucleotides in a programmable manner facilitates the formation of RNA-DNA origami structures, which can possess a well-defined morphology and serve as rigid supports for mRNA delivery. However, to date, comprehensive studies on the requirements for efficient folding of mRNA into distinct mRNA-DNA structures while preserving its translation functionality remain elusive. Here, the impact of design parameters on the folding of protein-encoding mRNA into mRNA-DNA origami structures is systematically investigated and the importance of the availability of ribosome-binding sequences on the translation efficiency is demonstrated. Furthermore, these hybrid structures are encapsulated inside virus capsids resulting in protecting them against nuclease degradation and also in enhancement of their cellular uptake. This multicomponent system therefore showcases a modular and versatile nanocarrier. The work provides valuable insight into the design of mRNA-DNA origami structures contributing to the development of mRNA-based gene delivery platforms.

Advanced Nanotechnology-Based Nucleic Acid Medicines

Nucleic acid medicines are a highly attractive modality that act in a sequence-specific manner on target molecules. To date, 21 such products have been approved by the Food and Drug Administration. However, the development of nucleic acid medicines continues to face various challenges, including tissue and cell targeting as well as intracellular delivery. Numerous research groups are addressing these issues by advancing the development of nucleic acid medicines through nanotechnology. In countries other than Japan (including Europe and the USA), >40 nanotechnology-based nucleic acid medicines have been tested in clinical trials, and 15 clinical trials are ongoing. In Japan, three phase I trials are ongoing, and future results are awaited. The review summarizes the latest research in the nanotechnology of nucleic acid medicines and statuses of clinical trials in Japan, with expectations of further evolutions.

Adaptable Self-Assembly of a PEG Dendrimer-Coiled Coil Conjugate

Self-assembly of designed molecules has enabled the construction of a variety of functional nanostructures. Specifically, adaptable self-assembly has demonstrated several advantageous features for smart materials. Here, we demonstrate that an α-helical coiled coil conjugated with a dendrimer can adapt to spatial restriction due to the strong steric repulsion between dendrimer chains. The adaptable transformation of a tetrameric coiled coil to a trimeric coiled coil can be confirmed using analytical ultracentrifugation upon conjugation of the dendrimer to the coiled coil-forming building block. Interestingly, circular dichroism spectroscopy analysis of the dendrimer conjugate revealed an unconventional trend: the multimerization of the coiled coil is inversely dependent on concentration. This result implies that the spatial crowding between the bulky dendritic chains is significantly stronger than that between linear chains, thereby affecting the overall assembly process. We further illustrated the application potential by decorating the surface of gold nanorods (AuNRs) with the adaptable coiled coil. The dendrimer-coiled coil peptide conjugate can be utilized to fabricate organic-inorganic nanohybrids with enhanced colloidal and thermal stabilities. This study demonstrates that the coiled coil can engage in the adaptable mode of self-assembly with the potential to form dynamic peptide-based materials.

Inhibition of protein-protein interactions using biodegradable depsipeptide nanoassemblies

Although peptides notoriously have poor intrinsic pharmacokinetic properties, it is well-known that nanostructures with excellent pharmacokinetic properties can be designed. Noticing that peptide inhibitors are generally nonpolar, here, we consolidate the peptide inhibitor targeting intracellular protein-protein interactions (PPIs) as an integral part of biodegradable self-assembled depsipeptide nanostructures (SdPNs). Because the peptide inhibitor has the dual role of PPI inhibition and self-assembly in this design, problems associated with the poor pharmacokinetics of peptides and encapsulation/entrapment processes can be overcome. Optimized SdPNs displayed better tumor targeting and PPI inhibition properties than the comparable small molecule inhibitor in vivo. Kinetics of PPI inhibition for SdPNs were gradual and controllable in contrast to the rapid inhibition kinetics of the small molecule. Because SdPN is modular, any appropriate peptide inhibitor can be incorporated into the platform without concern for the poor pharmacokinetic properties of the peptide.