Targeted Delivery of mRNA with One-Component Ionizable Amphiphilic Janus Dendrimers

Abstract

Targeted and efficient delivery of nucleic acids with viral and synthetic vectors is the key step of genetic nanomedicine. The four-component lipid nanoparticle synthetic delivery systems consisting of ionizable lipids, phospholipids, cholesterol, and a PEG-conjugated lipid, assembled by microfluidic or T-tube technology, have been extraordinarily successful for delivery of mRNA to provide Covid-19 vaccines. Recently, we reported a one-component multifunctional sequence-defined ionizable amphiphilic Janus dendrimer (IAJD) synthetic delivery system for mRNA relying on amphiphilic Janus dendrimers and glycodendrimers developed in our laboratory. Amphiphilic Janus dendrimers consist of functional hydrophilic dendrons conjugated to hydrophobic dendrons. Co-assembly of IAJDs with mRNA into dendrimersome nanoparticles (DNPs) occurs by simple injection in acetate buffer, rather than by microfluidic devices, and provides a very efficient system for delivery of mRNA to lung. Here we report the replacement of most of the hydrophilic fragment of the dendron from IAJDs, maintaining only its ionizable amine, while changing its interconnecting group to the hydrophobic dendron from amide to ester. The resulting IAJDs demonstrated that protonated ionizable amines play dual roles of hydrophilic fragment and binding ligand for mRNA, changing delivery from lung to spleen and/or liver. Replacing the interconnecting ester with the amide switched the delivery back to lung. Delivery predominantly to liver is favored by pairs of odd and even alkyl groups in the hydrophobic dendron. This simple structural change transformed the targeted delivery of mRNA mediated with IAJDs, from lung to liver and spleen, and expands the utility of DNPs from therapeutics to vaccines.

Zwitterionic Phospholipidation of Cationic Polymers Facilitates Systemic mRNA Delivery to Spleen and Lymph Nodes

“…Zwitterion incorporation could decrease the pK a of cationic polymers from ∼8.0 to ∼6.5, which is known to benefit in vivo mRNA delivery. 10,45 These observations highlight the advantages of zwitterionic phospholipidation modification of cationic polymers in safety and efficacy, which might be beneficial to overcoming delivery barriers and applicable for in vivo applications.…”

Backbone and side chain-linker tunability among dithiocarbamate, ester and amide in sequence-defined oligomers: synthesis and structure–property–function relationship

“…Recently, synthetic SDOs have proved their potency for various biomedical applications. 23 To investigate the transportability of the synthesised SDOs through serum, the protein binding affinity of the SDOs was determined with a model protein, serum albumin. The results for the Hg 2+ removal capacity and protein binding are discussed below individually.…”

Synthetic Conjugated Oligoelectrolytes Are Effective siRNA Transfection Carriers: Relevance to Pancreatic Cancer Gene Therapy

“…Therapeutics based on small interfering RNA (siRNA), in particular, display diminished adverse effects when compared with conventional chemotherapeutics. , This is because naked siRNA typically has poor stability in blood, do not enter cells by themselves, and are easily degradable in endo/lysosomes . A major challenge in clinical translation arises from the lack of effective and nontoxic delivery vehicles that can protect against ubiquitous RNase and achieve endo/lysosomal escape for effective release of siRNAs into the cytoplasm. , Accordingly, numerous delivery systems, for example, lipids, − cyclodextrin, nanogels, chitosan, cationic polymers, − cationic polyrotaxanes, − ionizable amphiphilic dendrimer, , inorganic materials, − and electroporation have been considered and studied to realize RNA-based therapeutics. Conventional nanocarriers, however, generally fail to simultaneously achieve desirable endo/lysosomal rupture and effective siRNA protection. , Ideal vectors for delivery thus constitute an unmet need to which the innovative design and application of materials capable of self-assembly with siRNA have much to contribute.…”

“…4 A major challenge in clinical translation arises from the lack of effective and nontoxic delivery vehicles that can protect against ubiquitous RNase and achieve endo/lysosomal escape for effective release of siRNAs into the cytoplasm. 5,6 Accordingly, numerous delivery systems, for example, lipids, 7−13 cyclodextrin, 14 nanogels, 15 chitosan, 16 cationic polymers, 17−23 cationic polyrotaxanes, 24−28 ionizable amphiphilic dendrimer, 29,30 inorganic materials, 31−34 and electroporation 35 have been considered and studied to realize RNA-based therapeutics. Conventional nanocarriers, however, generally fail to simultaneously achieve desirable endo/lysosomal rupture and effective siRNA protection.…”