Preparation and evaluation of polyamidoamine dendrimer (G2)/branched-β-cyclodextrin conjugate as a novel gene transfer carrier

Twenty Years of Research on Cyclodextrin Conjugates with PAMAM Dendrimers

Recently, the number of gene and oligonucleotide drugs are increasing. Of various drug delivery systems (DDSs) for gene and oligonucleotide drugs, few examples of the clinical application of polymer as drug carriers are known, despite development of the novel polymers has been progressing. Cyclodextrin (CD) conjugates with starburst polyamidoamine (PAMAM) dendrimer (CDEs), as a new type of polymer-based carriers, were first published in 2001. After that, galactose-, lactose-, mannose-, fucose-, folate-, and polyethyleneglycol (PEG)-appended CDEs have been prepared for passive and active targeting for gene, oligonucleotide, and low-molecular-weight drugs. PEG-appended CDE formed polypsuedorotaxanes with α-CD and γ-CD, which are useful for a sustained release system of gene and oligonucleotide drugs. Interestingly, CDEs were found to have anti-inflammatory effects and anti-amyloid effects themselves, which have potential as active pharmaceutical ingredients. Most recently, CDE is reported to be a useful Cas9-RNA ribonucleoproteins (Cas9 RNP) carrier that induces genome editing in the neuron and brain. In this review, the history and progression of CDEs are overviewed.

Genome Editing in a Wide Area of the Brain Using Dendrimer-Based Ternary Polyplexes of Cas9 Ribonucleoprotein

A preassembled Cas9/single-guide RNA complex (Cas9 ribonucleoprotein; Cas9 RNP) induces genome editing efficiently, with small off-target effects compared with the conventional techniques, such as plasmid DNA and mRNA systems. However, penetration of Cas9 RNP through the cell membrane is low. In particular, the incorporation of Cas9 RNP into neurons and the brain is challenging. In the present study, we have reported the use of a dendrimer (generation 3; G3)/glucuronylglucosyl-β-cyclodextrin conjugate (GUG-β-CDE (G3)) as a carrier of Cas9 RNP and evaluated genome editing activity in the neuron and the brain. A Cas9 RNP ternary complex with GUG-β-CDE (G3) was prepared by only mixing the components. The resulting complex exhibited higher genome editing activity than the complex with the dendrimer (G3), Lipofectamine 3000 or Lipofectamine CRISPRMAX in SH-SY5Y cells, a human neuroblastoma cell line. In addition, GUG-β-CDE (G3) enhanced the genome editing activity of Cas9 RNP in the whole mouse brain after a single intraventricular administration. Thus, GUG-β-CDE (G3) is a useful Cas9 RNP carrier that can induce genome editing in the neuron and brain.

Cyclodextrin-based multivalent glycodisplays: covalent and supramolecular conjugates to assess carbohydrate-protein interactions

Covalent attachment of biorecognizable sugar ligands in several copies at precise positions of cyclomaltooligosaccharide (cyclodextrin, CD) macrocycles has proven to be an extremely flexible strategy to build multivalent conjugates. The commercial availability of the native CDs in three different sizes, their axial symmetry and the possibility of position- and face-selective functionalization allow a strict control of the valency and spatial orientation of the recognition motifs (glycotopes) in low, medium, high and hyperbranched glycoclusters, including glycodendrimer-CD hybrids. "Click-type" ligation chemistries, including copper(i)-catalyzed azide-alkyne cycloaddition (CuAAC), thiol-ene coupling or thiourea-forming reactions, have been implemented to warrant full homogeneity of the adducts. The incorporation of different glycotopes to investigate multivalent interactions in heterogeneous environments has also been accomplished. Not surprisingly, multivalent CD conjugates have been, and continue to be, major actors in studies directed at deciphering the structural features ruling carbohydrate recognition events. Nanometric glycoassemblies endowed with the capability of adapting the inter-saccharide distances and orientations in the presence of a receptor partner or capable of mimicking the fluidity of biological membranes have been conceived by multitopic inclusion complex formation, rotaxanation or self-assembling. Applications in the fields of sensors, site-specific drug and gene delivery or protein stabilization attest for the maturity of the field.

Polyamidoamine Dendrimer Conjugates with Cyclodextrins as Novel Carriers for DNA, shRNA and siRNA

Gene, short hairpin RNA (shRNA) and small interfering RNA (siRNA) delivery can be particularly used for the treatment of diseases by the entry of genetic materials mammalian cells either to express new proteins or to suppress the expression of proteins, respectively. Polyamidoamine (PAMAM) Starburst^TM dendrimers are used as non-viral vectors (carriers) for gene, shRNA and siRNA delivery. Recently, multifunctional PAMAM dendrimers can be used for the wide range of biomedical applications including intracellular delivery of genes and nucleic acid drugs. In this context, this review paper provides the recent findings on PAMAM dendrimer conjugates with cyclodextrins (CyDs) for gene, shRNA and siRNA delivery.

Potential Use of Polyamidoamine Dendrimer Conjugates with Cyclodextrins as Novel Carriers for siRNA

Cyclodextrin (CyD)-based nanoparticles and polyamidoamine (PAMAM) starburst dendrimers (dendrimers) are used as novel carriers for DNA and RNA. Recently, small interfering RNA (siRNA) complex with β-CyD-containing polycations (CDP) having adamantine-PEG or adamantine-PEG-transferrin underwent a phase I study for treatment of solid tumors. Multifunctional dendrimers can be used for a wide range of biomedical applications, including the interaction and intracellular delivery of DNA and RNA. The present review will address the latest developments in dendrimer conjugates with cyclodextrins for siRNA delivery including the novel sustained release system.