Biophysical Society Thematic Meeting | Ascona, Switzerland

Liposomes, Exosomes, and Virosomes: From Modeling Complex Membrane Processes to Medical Diagnostics and Drug Delivery

Tuesday Speaker Abstracts

Mechanics of Extracellular Vesicles from Plasmodium Falciparum Infected Red Blood Cells Raya Sorkin 1 , Daan Vorselen 1 , Yifat Ofir-Birin 2 , Wouter Roos 1 , Fred MacKintosh 1 , Neta Regev-Rudzki 2 , Gijs Wuite 1 . 1 VU University Amsterdam, Amsterdam, Netherlands, 2 Weizmann Institute of Science, Rehovot, Israel. Malaria is a life-threatening disease caused by parasites that are transmitted through the bites of infected mosquitoes, with Plasmodium falciparum (Pf) causing the most severe form of malaria (1). Very recently it was discovered that Pf infected red blood cells (iRBC) directly transfer information between parasites within a population using exosome like-vesicles that are capable of delivering genes (2). This communication promotes parasite differentiation to sexual forms and is critical for its survival in the host and transmission to mosquitoes. Efficient DNA transfer via extracellular vesicles (EVs) occurs mainly at the early ring stage within the blood-stage asexual cycle, and it can be inhibited by addition of actin polymerization inhibitors. This suggests that actin polymerization is required for cell-cell communication (2). We expect, therefore, that mechanical properties of vesicles at different stages of the life cycle will be optimized for their function, and more specifically, the stiffness of the ring stage EVs is likely better optimized for efficient DNA-dependent communication. With the aim to understand how mechanical properties of EVs effect their efficiency of cargo delivery, we use Atomic Force Microscopy for mechanical characterization of extracellular vesicles secreted from Pf infected RBCs. We perform a detailed comparison between the mechanical properties (bending modulus values) of these vesicles and those secreted from healthy RBCs, as well as compare their size and morphology. We also prepare and characterize synthetic vesicles (SVs) with varying mechanical strength to determine how stiffness of SVs affects their adhesion to cells and cellular uptake rate, to gain a broader understanding of the link between mechanical properties and efficient cellular uptake.

1. WHO http://www.who.int/mediacentre/factsheets/fs094/en/. 2. N. Regev-Rudzki et al., Cell 153, 1120 (May 23, 2013).

Phase Transitions: An Emerging Principle in Cytoplasmic Organization and Neurodegeneration Anthony Hyman Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany

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