Protein carrier system based on cyanobacterial nano-sized extracellular vesicles

Abstract

The present invention refers to a genetic construct for carrying a protein of interest in cyanobacterial extracellular vesicles (EVs) of Synechocystis sp. PCC6803. The present invention further relates to the derived transformed Synechocystis strain comprising the said construct. Cyanobacterium transformed with referred construct are, most surprisingly, further characterized by hypervesiculating EVs to larger extents than the wild-type and mutant strains known in the art. Cyanobacterium transformed with the referred construct secrete the protein of interest in EVs and to the extracellular medium thus, the present invention also refers to compositions comprising EVs derived from the said transformed Synechocystis strain, as well as compositions comprising the EV-free extracellular medium derived from the said transformed Synechocystis strain, for use in carrying proteins proteins / enzymes into animals, including mammals and fish. The present invention further refers to methods for transforming mammalian epithelial cells with EVs isolated from the said Synechocystis strain, which internalize the said EVs and display the protein of interest. Moreover, the present invention refers to methods by which cyanobacterial EVs can work as nanocarriers of custom proteins into fish, with prospective applications in modulation of nutritional status or stimulating specific adaptive immune responses. The construct, strain, compositions uses and methods in the present invention may be advantageously employed as a novel biotechnological tool for the specific delivery of biologically active proteins and enzymes in biotechnology in general and in aquaculture in specific.

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