Lipid-derived nanoparticles for immunostimulatory RNA adjuvant delivery

Abstract

The specific activation of Toll-like receptors (TLRs) has potential utility for a variety of therapeutic indications including antiviral immunotherapy and as vaccine adjuvants. TLR7 and TLR 8 may be activated by their native ligands, single-stranded RNA, or by small molecules of the imidazoquinoline family. However the use of TLR7/8 agonists for in vivo therapy is limited by instability, in the case of RNA, or systemic biodistribution and toxicity in the case of small molecule agonists. We hypothesized that unique lipid-like materials, termed "lipidoids," could be designed to efficiently deliver immunostimulatory RNA (isRNA) to TLR-expressing cells to drive innate and adaptive immune responses. A library of lipidoids was synthesized and screened for the ability to induce type I IFN activation in human peripheral blood mononuclear cells when combined with isRNA oligonucleotides. Effective lipidoid-isRNA nanoparticles, when tested in mice, stimulated strong IFN-α responses following subcutaneous injection, had robust antiviral activity that suppressed influenza virus replication, and enhanced antiovalbumin humoral and cell-mediated responses when used as a vaccine adjuvant. Further, we demonstrate that whereas all immunological activity was MyD88-dependent, certain materials were found to engage both TLR7-dependent and TLR7-independent activity in the mouse suggestive of cell-specific delivery. These lipidoid formulations, which are materials designed specifically for delivery of isRNA to Toll-like receptors, were superior to the commonly used N-[1-(2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium methylsulfate-RNA delivery system and may provide new tools for the manipulation of TLR responses in vitro and in vivo.innate immunity | dendritic cell | drug delivery | high-throughput screening

Nanocarriers for Delivery of siRNA and Co-Delivery of siRNA and Other Therapeutic Agents

“…Lipidoid is a lipid-like material consisting of an amine-containing head group and hydrocarbon tails, which is synthesized via epoxide ring-opening by amine substrate [77]. Study on cynomolgus monkeys showed that iv.…”

Immunomodulatory spherical nucleic acids

“…Efforts have primarily focused on constructs for immunostimulation (IS) and include complexing oligonucleotides with albumin (15), gold nanoparticles with two-component external coronas consisting of IS-oligonucleotides together with protein antigens (16), gold nanoparticle-IS-oligonucleotide conjugates (17), IS-oligonucleotides conjugated to polymeric nanoparticles (18), and IS-oligonucleotides in complex with lipids (19). Although these studies have uncovered the promise of nanomaterials for immunomodulation, it is still unclear what the dominant structural factors are.…”

Self-assembled Micelle Interfering RNA for Effective and Safe Targeting of Dysregulated Genes in Pulmonary Fibrosis

“…Unmodified naked siRNAs are degraded rapidly by nuclease in the circulation and removed efficiently through renal clearance (34,35). In addition, activation of nonspecific innate immune stimulation of short RNA sequences could be a significant problem with repetitive and high-dose therapeutic application of siRNAs (5,6). Therefore, to achieve optimal in vivo siRNA delivery and specific silencing, it is imperative to develop modified siRNA or strategies that allow protection of siRNAs from nuclease degradation and facilitate cellular uptake for efficient gene silencing without significant immunogenicity.…”

“…Naked nucleic acid molecules, including synthetic siRNA, are degraded easily by ubiquitous nucleases either in the circulation or inside cells, and they are unable to enter cells through passive diffusion mechanisms because of the large molecular weight and polycationic nature of the chemical structure (4). In addition, the nonspecific innate immune-stimulatory function of siRNA could be a serious problem, especially for repetitive and high-dose therapeutic applications (5,6). In the last decade, various approaches have been developed to overcome these issues.…”