Dynamic interactors: Galectins and EVs

Background

Mesenchymal stem cells (MSCs) revealed promising therapeutic effects in various clinical applications, primarily through paracrine signaling, through their extracellular vesicles (EVs), serving as effective mediators of cell-free therapy, circumventing safety concerns. Galectins are carbohydrate-binding proteins with promising immunomodulatory properties. Here, we investigate the relationship between MSC-EVs and galectins caused by the findings of their co-existence in EV preparations.

 

Methods

We used different methods (ELISA and Flow cytometry) to detect the presence and binding of Galectin-1 and -3 to MSC EVs. To provide insights into the strength of interactions between EVs and the molecules of interest, such as galectins and the CD63 antibody, we used Flow- Induced Dispersion Analysis (FIDA).   

 

Results

Flow cytometric analysis showed double positive populations for galectin- and tetraspanin-positive EVs, as well as single galectin positive particles. The effective binding number of EVs (EC50) with FIDA could be determined. Different concentrations of the CD63 antibody showed that low concentrations lead to a more effective binding and that it depends on the interaction time. For galectin-1 and -3, we detected weak binding to MSC EVs because we were working with particle numbers under the EC50. We could detect clear binding for galectin-1 and -3 for standard EVs from Serum. 

 

Conclusion

Our results confirm that galectins are present in EV preparations and further interact directly with each other by active binding. These findings suggest that EVs and galectins are natural dynamic interactors in vitro and ex vivo.

 

Keywords

Galectins, EVs, Binding, Dynamic interaction 

 

Authors

Maria-Anthi Kakavoulia1 (Corresponding Author: M.Kakavoulia[at]lmu[dot]de), Peter Spies2, Hadi Karimzadeh1, Bernd Giebel3, Tobias Tertel3,  Xavier Blanchet4, Herbert Kaltner1, Tanja-Jasmin Kutzner3, Anna-Kristin Ludwig1

 

1 Physiological Chemistry, Department of Veterinary Sciences, Faculty of Veterinary Medicine, Ludwig-Maximilians-Universität Munich, Germany 
2University of Applied Sciences, School of Life Sciences, Muttenz, Switzerland

3Institute for Transfusion Medicine, University Hospital Essen, University of Duisburg-Essen, Germany
4Institute for Cardiovascular Prevention (IPEK), Ludwig-Maximilians-Universität Munich, Germany

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