The present disclosure provides, at least in part, methods and compositions for in vivo fusosome delivery. In some embodiments, the fusosome comprises a combination of elements that promote specificity for target cells, e.g., one or more of a fusogen, a positive target cell-specific regulatory element, and a non-target cell-specific regulatory element. In some embodiments, the fusosome comprises one or more modifications that decrease an immune response against the fusosome.

The invention provides solid lipid nanoparticles (SLNs) which comprise gold, and are useful as vectors for the transfection of different types of nucleic acids. Different methods for obtaining such SLNs are also disclosed.

The present disclosure provides compositions which shown preferential targeting or delivery of a nucleic acid composition to a particular organ. In some embodiments, the composition comprises a steroid or sterol, an ionizable cationic lipid, a phospholipid, a PEG lipid, and a permanently cationic lipid which may be used to deliver a nucleic acid.

Covalently linked linear polyethylenimine (PEI) clusters are provided that change conformation depending upon changes in counterion concentrations. The structures may be used for the storage, delivery, and/or transport of substances.

The invention provides a platform and methods of using the platform for the regulation of the expression of a target gene using exposure to an aptamer ligand (for example, a small molecule). The platform features a polynucleotide gene regulation cassette that is placed in the target gene and includes a synthetic riboswitch positioned in the context of a 5′ intron-alternative exon-3′ intron. The riboswitch comprises an effector region and a sensor region (e.g., an aptamer that binds a small molecule ligand) such that the alternative exon is spliced into the target gene mRNA when the ligand is not present thereby preventing expression of the target gene. When the ligand is present, the alternative exon is not spliced into the target gene mRNA thereby providing expression of the target gene.

This disclosure relates to ionizable lipid-based lipid nanoparticles for delivery of mRNA encoding glucose-6-phosphatase. Lipid nanoparticle/mRNA therapies of the invention increase and/or restore deficient levels of glucose-6-phosphatase expression and activity in subjects and are useful for the treatment of glycogen storage disease type 1a (GSD-Ia). Lipid nanoparticle/mRNA therapies of the invention increase glucose production and reduce the abnormal accumulation of glycogen and glucose-6-phosphate associated with GSD-Ia.

The present invention provides stable, dry powder messenger RNA formulations for therapeutic use, and methods of making and using the same.

The present invention relates to compositions comprising a delivery vehicle conjugated to a targeting domain, wherein the delivery vehicle comprises at least one agent, and wherein the targeting domain specifically binds to an CD4.sup.+ T cell antigen. The invention also relates to methods of treating or preventing diseases and disorders, including cancers, infectious diseases, and immunological disorders, using the described compositions.

Peptide-based systems containing hydrophobic amino acids (e.g., tryptophan), charged amino acids (e.g., arginine), and/or sulfur-containing amino acids (e.g., cysteine), which can be used either alone or in combination with nanoparticles (e.g., gold or silver nanoparticles) for siRNA delivery into living cells are disclosed.

The invention relates to compositions including polynucleotides encoding polypeptides which have been chemically modified by replacing the uridines with 1-methyl-pseudouridine to improve one or more of the stability and/or clearance in tissues, receptor uptake and/or kinetics, cellular access by the compositions, engagement with translational machinery, mRNA half-life, translation efficiency, immune evasion, protein production capacity, secretion efficiency, accessibility to circulation, protein half-life and/or modulation of a cell's status, function, and/or activity.