1. Antibacterial Effect of Honey-Derived Exosomes Containing Antimicrobial Peptides Against Oral Streptococci
Camila Leiva-Sabadini, Simon Alvarez, Nelson P Barrera, Christina M A P Schuh, Sebastian Aguayo Int J Nanomedicine. 2021 Jul 20;16:4891-4900. doi: 10.2147/IJN.S315040. eCollection 2021.
Purpose: Recently, our group found exosome-like extracellular vesicles (EVs) in Apis mellifera honey displaying strong antibacterial effects; however, the underlying mechanism is still not understood. Thus, the aim of this investigation was to characterize the molecular and nanomechanical properties of A. mellifera honey-derived EVs in order to elucidate the mechanisms behind their antibacterial effect, as well as to determine differential antibiofilm properties against relevant oral streptococci. Methods: A. mellifera honey-derived EVs (HEc-EVs) isolated via ultracentrifugation were characterized with Western Blot and ELISA to determine the presence of specific exosomal markers and antibacterial cargo, and atomic force microscopy (AFM) was utilized to explore their ultrastructural and nanomechanical properties via non-destructive immobilization onto poly-L-lysine substrates. Furthermore, the effect of HEc-EVs on growth and biofilm inhibition of S. mutans was explored with microplate assays and compared to S. sanguinis. AFM was utilized to describe ultrastructural and nanomechanical alterations such as cell wall elasticity changes following HEc-EV exposure. Results: Molecular characterization of HEc-EVs identified for the first time important conserved exosome markers such as CD63 and syntenin, and the antibacterial molecules MRJP1, defensin-1 and jellein-3 were found as intravesicular cargo. Nanomechanical characterization revealed that honey-derived EVs were mostly <150nm, with elastic modulus values in the low MPa range, comparable to EVs from other biological sources. Furthermore, incubating oral streptococci with EVs confirmed their antibacterial and antibiofilm capacities, displaying an increased effect on S. mutans compared to S. sanguinis. AFM nanocharacterization showed topographical and nanomechanical alterations consistent with membrane damage on S. mutans.
2. Royal jelly extracellular vesicles promote wound healing by modulating underlying cellular responses
Simón Álvarez, et al. Mol Ther Nucleic Acids. 2023 Feb 14;31:541-552. doi: 10.1016/j.omtn.2023.02.008. eCollection 2023 Mar 14.
Apis mellifera royal jelly (RJ) is a well-known remedy in traditional medicine around the world and its versatile effects range from antibacterial to anti-inflammatory properties and pro-regenerative properties. As a glandular product, RJ has been shown to contain a substantial number of extracellular vesicles (EVs), and, in this study, we aimed to investigate the extent of involvement of RJEVs in wound healing-associated effects. Molecular analysis of RJEVs verified the presence of exosomal markers such as CD63 and syntenin, and cargo molecules MRJP1, defensin-1, and jellein-3. Furthermore, RJEVs were demonstrated to modulate mesenchymal stem cell (MSC) differentiation and secretome, as well as decrease LPS-induced inflammation in macrophages by blocking the mitogen-activated protein kinase (MAPK) pathway. In vivo studies confirmed antibacterial effects of RJEVs and demonstrated an acceleration of wound healing in a splinted mouse model. This study suggests that RJEVs play a crucial role in the known effects of RJ by modulating the inflammatory phase and cellular response in wound healing. Transfer of RJ into the clinics has been impeded by the high complexity of the raw material. Isolating EVs from the raw RJ decreases the complexity while allowing standardization and quality control, bringing a natural nano-therapy one step closer to the clinics.
