Extracellular Vesicles Tropism: A Comparative Study between Passive Innate Tropism and the Active Engineered Targeting Capability of Lymphocyte-Derived EVs.

Tania Limongi,Luisa Racca,Francesca Susa,Doriana Debellis,Michela Perrone Donnorso,Bianca Dumontel,Valentina Cauda

doi:10.3390/membranes11110886

Abstract

Cellular communications take place thanks to a well-connected network of chemical–physical signals, biomolecules, growth factors, and vesicular messengers that travel inside or between cells. A deep knowledge of the extracellular vesicle (EV) system allows for a better understanding of the whole series of phenomena responsible for cell proliferation and death. To this purpose, here, a thorough immuno-phenotypic characterization of B-cell EV membranes is presented. Furthermore, the cellular membrane of B lymphocytes, Burkitt lymphoma, and human myeloid leukemic cells were characterized through cytofluorimetry assays and fluorescent microscopy analysis. Through cytotoxicity and internalization tests, the tropism of B lymphocyte-derived EVs was investigated toward the parental cell line and two different cancer cell lines. In this study, an innate capability of passive targeting of the native EVs was distinguished from the active targeting capability of monoclonal antibody-engineered EVs, able to selectively drive the vesicles, enhancing their internalization into the target cancer cells. In particular, the specific targeting ability of anti-CD20 engineered EVs towards Daudi cells, highly expressing CD20 marker on their cell membrane, was proved, while almost no internalization events were observed in HL60 cells, since they did not express an appreciable amount of the CD20 marker on their plasma membranes.

Highlights

There are no more doubts that inter- and intracellular traffic mediated by vesicles represents a key role in the circulation of molecules between membrane-enclosed compartments of different secretory pathways
transmission electron microscopy (TEM) images in Figure 2A,B showed a heterogeneous population of extracellular vesicles, among which exosomes were recognizable from their typical cup shape
The average concentrations reported by the NTA measurements was 1 × 1011 ± 6 × 1010 part/mL, while an example of the size distribution of lymphocyte-derived extracellular vesicle (EV) is provided in Figure 2C; the protein content, measured by Bradford assay on the same isolations, was 140 ± 36 μg/mL, 3

Summary

Introduction

There are no more doubts that inter- and intracellular traffic mediated by vesicles represents a key role in the circulation of molecules between membrane-enclosed compartments of different secretory pathways. By avoiding referring to everything related to transport among the various compartments of the same cell, intercellular communication is central for the preservation of cell–cell homeostasis in tissues, organs, and systems of the whole human body. All cells secrete double-layered phospholipid membrane vesicles into the extracellular environment. These are ubiquitarian vesicles since they can be isolated from blood, saliva, urine, seminal fluid, breast milk, and amniotic and cerebrospinal fluid [1,2,3]. These vesicles are generically grouped as “extracellular vesicles” (EVs) [4,5]

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Discussion

Conclusion