Proteins, nucleic acids encoding the proteins, compositions comprising the proteins, and methods are provided. The proteins have the ability to be self-targeted to ICAM-1 and, if desired, enzymatically-released at acidic pH. The ICAM-1-targeting peptides are provided as single copies or multiples repeats, and can be separated by linkers from the enzyme segment, from which the ICAM-1 targeting peptides can be released, if desired, at acidic pH. These fusion proteins enhance the activity of the enzyme segment within or liberated from the fusion protein, and provide increased recognition and targeting of diseased organs, transport from the bloodstream across the endothelium into said diseased organ, and intracellular uptake and lysosomal trafficking by cells in them, both in peripheral tissues and the central nervous system. Representative nucleotide and amino acid sequences of these fusion proteins, as well as in vitro, cellular, and in vivo animal data are provided. The described proteins can be used as a protein therapy, a gene therapy, or an implanted cell therapy.

The present application relates to methods of producing exosomes. The application also provides a method for preparing a protein composition comprising culturing an exosome-producing cell expressing a Nef-fusion protein comprising a Nef-derived peptide fused to a protein of interest; isolating exosomes from the exosome-producing cell culture; and purifying the protein of interest from the isolated exosomes. The application further discloses compositions that comprise exosomes containing the Nef-fusion protein, as well as methods of using the Nef-fusion protein and exosomes containing the Nef-fusion protein.

Described herein are compositions and techniques related to generation and therapeutic application of artificial synapses. Artificial synapses are engineered extracellular vesicles, including exosomes, which incorporate sticky binders on their surface to anchor signaling domains against biological targets, such as receptors. These engineered additives can be organized in genetic vector constructs, expressed in mammalian cells, wherein the sticky binders attach to extracellular vesicles such as exosomes, thereby presenting their joined signaling domains which are rapidly taken up by recipient cells. Artificial synapses adopt the hallmark biophysical and biochemical features of extracellular vesicles, allowing for rapid deployment and scale-up. Importantly, this strategy can allow for kinetically favorable signal generation and signal propagation. This includes, for example, increasing density of agonist presentation to support receptor clustering—an onerous barrier for traditional receptor targeting strategies.

Described herein are compositions and techniques related to generation and therapeutic application of artificial synapses. Artificial synapses are engineered extracellular vesicles, including exosomes, which incorporate sticky binders on their surface to anchor signaling domains against biological targets, such as receptors. These engineered additives can be organized in genetic vector constructs, expressed in mammalian cells, wherein the sticky binders attach to extracellular vesicles such as exosomes, thereby presenting their joined signaling domains which are rapidly taken up by recipient cells. Artificial synapses adopt the hallmark biophysical and biochemical features of extracellular vesicles, allowing for rapid deployment and scale-up. Importantly, this strategy can allow for kinetically favorable signal generation and signal propagation. This includes, for example, increasing density of agonist presentation to support receptor clustering an onerous barrier for traditional receptor targeting strategies.

The invention includes systems, methods, and compositions for designing secreted fusogenic ectosome vesicles, or gectosomes, that selectively encapsulate specific target proteins, nucleic acids and/or other small molecules in a predetermined manner. These engineered gectosomes can be used to deliver desired cargos to receipt cells in vitro, ex vivo, or in vivo and may further reprogram target cellular phenotypes in a dose-dependent manner, as well as perform genome editing functions, among others.

Described herein are compositions and techniques related to generation and therapeutic application of artificial synapses. Artificial synapses are engineered extracellular vesicles, including exosomes, which incorporate sticky binders on their surface to anchor signaling domains against biological targets, such as receptors. These engineered additives can be organized in genetic vector constructs, expressed in mammalian cells, wherein the sticky binders attach to extracellular vesicles such as exosomes, thereby presenting their joined signaling domains which are rapidly taken up by recipient cells. Artificial synapses adopt the hallmark biophysical and biochemical features of extracellular vesicles, allowing for rapid deployment and scale-up. Importantly, this strategy can allow for kinetically favorable signal generation and signal propagation. This includes, for example, increasing density of agonist presentation to support receptor clustering—an onerous barrier for traditional receptor targeting strategies.

The present application relates to methods of producing exosomes. The application also provides a method for preparing a protein composition comprising culturing an exosome-producing cell expressing a Nef-fusion protein comprising a Nef-derived peptide fused to a protein of interest; isolating exosomes from the exosome-producing cell culture; and purifying the protein of interest from the isolated exosomes. The application further discloses compositions that comprise exosomes containing the Nef-fusion protein, as well as methods of using the Nef-fusion protein and exosomes containing the Nef-fusion protein.

Provided herein are recombinant CTLA-4 binding proteins, which are, inter alia, useful for the treatment of cancer. The recombinant proteins provided herein are, inter alia, capable of binding CTLA-4 proteins on a tumor cell. In a first aspect, there is provided a recombinant CTLA-4 binding protein including (i) a CTLA-4 binding domain; (ii) a CTLA-4 binding domain masking peptide; and (iii) a cleavable peptide linker connecting the CTLA-4 binding domain masking peptide to the CTLA-4 binding domain. In another aspect, there is provided a dimerizing domain covalently attached to the CTLA-4 binding domain, wherein the binding protein domains are bound together.

Recombinant therapeutic cytokines (“therakines”) for the treatment of cancer are provided. The recombinant therakines include a truncated region of MDA-7/TL-24 (“M4”) not normally found in nature that has anti-cancer activity and a secretory signal which causes secretion of the therakine from plasmid/virus transduced normal and cancer cells and interaction of the therakine to MDA-7/IL-24 receptors on adjacent, neighboring and distant cancer cells. Therakine interaction results in bystander killing of the target cancer cell as well as adjacent, neighboring and distant cancer cells.

Proteins, nucleic acids encoding the proteins, compositions comprising the proteins, and methods are provided. The proteins have the ability to be self-targeted to ICAM-1 and, if desired, enzymatically-released at acidic pH. The ICAM-1-targeting peptides are provided as single copies or multiples repeats, and can be separated by linkers from the enzyme segment, from which the ICAM-1 targeting peptides can be released, if desired, at acidic pH. These fusion proteins enhance the activity of the enzyme segment within or liberated from the fusion protein, and provide increased recognition and targeting of diseased organs, transport from the bloodstream across the endothelium into said diseased organ, and intracellular uptake and lysosomal trafficking by cells in them, both in peripheral tissues and the central nervous system. Representative nucleotide and amino acid sequences of these fusion proteins, as well as in vitro, cellular, and in vivo animal data are provided. The described proteins can be used as a protein therapy, a gene therapy, or an implanted cell therapy.