Figure 2.

Naturally occurring and engineered exosomes for therapeutic purposes. Naturally occurring exosomes from stem cells have shown the protective effects on the survival and proliferation of cells such as cardiomyocytes. Cells loaded with exogenous cargo including siRNAs, miRNAs, and shRNAs secrete exosomes containing these siRNAs, miRNAs, or shRNA-derived miRNAs. Cells expressing target peptides by plasmid transfection produce exosomes that can target specific cell populations. Exogenous cargo can be directly loaded into exosomes by electroporation, lipofection, sonication or Ca²⁺. Exosomes loaded with endogenous and/or exogenous cargo can be taken up by recipient cells for the regulation of gene expression.