PhD Scientific Days 2026

Molecular Medicine 4.

The effect of the OMV-treated BeWo-derived EVs on THP-1 cells

Name of the presenter

Seregélyes, Gábor

Institute/workplace of the presenter

Institute of Genetics, Cell and Immunobiology

Authors

Gábor Seregélyes¹
1: Institute of Genetics, Cell and Immunobiology

Text of the abstract

INTRODUCTION
The production of extracellular vesicles (EVs) is a common biological phenomenon in both eukaryotic and prokaryotic cells. Gram-negative EVs are formed by blebbing from the outer membrane; hence the name outer membrane vesicle (OMV). OMVs have several functions, which can be mediated by multiple exofacial and internal biomolecules. These components enable the OMVs to have a similar effect to that of the whole bacterium on the cell.
AIMS
We hypothesized that the composition of trophoblast-derived EVs changes in an infectious environment thereby influences the function of macrophages.
METHODES
The BeWo choriocarcinoma cell line, differentiated BeWo cells (syncytiotrophoblasts, STBs) and the THP-1 monocytic cells were used in an in vitro model system. Infection was mimicked by treating the cells with OMVs. The OMVs were isolated using differential centrifugation. Their characteristics were determined using TEM, NTA and flow cytometry, as well as by measuring the protein/lipid ratio. The effects of OMV-induced changes in cell function, including adhesiveness, proliferation capacity and cytokine production, were assessed using impedimetry (xCELLigence system), flow cytometry and RT-PCR. The effects of OMV-treated BeWo-derived EVs on THP-1 cells were also investigated using flow cytometry and impedance analysis.
RESULTS
The method of isolating the OMVs has been successfully standardized.
Treatment with OMVs increased the adhesiveness of THP-1 cells within the first eight hours. OMVs did not modify the proliferative activity of THP-1 cells, but they did induce higher ICAM-1 expression, which explains the increased adhesiveness. Following OMV treatment, the expression levels of proinflammatory genes (STAT1, TNF-α) also increased, which may be associated with M1 polarization of the cell.
The uptake of BeWo-EVs by THP-1 cells was affected by the differentiation stage and environmental factors. The highest uptake was observed in our infection model when STB cells were treated with OMV.
CONCLUSION
OMV-treatment is a useful in vitro infection model. Therefore, standardization of OMV isolation method and the characterization of isolated OMVs are essential for cell function tests induced by bacterial EVs.
The functional changes induced in trophoblast cells by OMV treatment can be used to model infection-associated pregnancy complications