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Morandi MI, Busko P, Ozer-Partuk E, Khan S, Zarfati G, Elbaz-Alon Y, Abou Karam P, Napso Shogan T, Ginini L, Gil Z, Regev-Rudzki N, Avinoam O. Extracellular vesicle fusion visualized by cryo-electron microscopy. PNAS Nexus 2022; 1:pgac156. [PMID: 36714848 PMCID: PMC9802263 DOI: 10.1093/pnasnexus/pgac156] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/30/2022] [Accepted: 08/09/2022] [Indexed: 02/01/2023]
Abstract
Extracellular vesicles (EVs) transfer bioactive molecules between cells in a process reminiscent of enveloped viruses. EV cargo delivery is thought to occur by protein-mediated and pH-dependent membrane fusion of the EV and the cellular membrane. However, there is a lack of methods to identify the fusion proteins and resolve their mechanism. We developed and benchmarked an in vitro biophysical assay to investigate EV membrane fusion. The assay was standardized by directly comparing EV and viral fusion with liposomes. We show that EVs and retroviruses fuse with liposomes mimicking the membrane composition of the late endosome in a pH- and protein-dependent manner. Moreover, we directly visualize the stages of membrane fusion using cryo-electron tomography. We find that, unlike most retroviruses, EVs remain fusogenic after acidification and reneutralization. These results provide novel insights into the EV cargo delivery mechanism and an experimental approach to identify the EV fusion machinery.
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Affiliation(s)
- Mattia I Morandi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Petro Busko
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Efrat Ozer-Partuk
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Suman Khan
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Giulia Zarfati
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yael Elbaz-Alon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Paula Abou Karam
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | | | - Lana Ginini
- Faculty of Health, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Ziv Gil
- Faculty of Health, Bar Ilan University, Ramat-Gan 5290002, Israel,Head and Neck Center, Holy Family Hospital, Nazareth 1641100, Israel
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