PhD Scientific Days 2024

Molecular Medicine III.

The Effect of Extracellular Vesicles Originated from Mesenchymal Cells of Peritoneal Dialysate on the Mechanism of Fibrosis

Text of the abstract

Introduction: The literature is abundant on the topic of benefits of cell therapy in different experimental fibrosis models. Using extracellular vesicles (EVs) as an alternative to cell therapy promises benefits like lower immunogenicity, a possible crossing of the blood-brain barrier, and not inducing acute immune rejection.
Aims: We investigated the effect of EVs originating from mesenchymal cells (MCs) of peritoneal dialysate (PDE) on the activation of primary MCs and fibroblasts.
Methods: MCs were isolated, characterized, and cultured from PDE. From the serum-free cultures supernatant EVs were isolated by tangential flow filtration and size exclusion chromatography. After the isolation EVs were characterized based on their particle number, size distribution, morphological features, surface markers, and the composition of cargo proteins. Their effect on fibroblast activation was tested by in vitro experiments on primary peritoneal fibroblasts (pFBs) isolated from peritoneal biopsy collected during the removal of the Tenchoff catheter. The effects of EVs on the pFBs were examined by using functional assays such as MTT proliferation assay, Sirius Red assay, and Transient Agarose Spot assay.
Results: The mesenchymal cells isolated in the study displayed positive expressions of CK-18, α-SMA, CD73, CD105, and CD90 while lacking the CD34, HLA-DR, CD45, and CD19 markers as indicated by immunofluorescent staining and RT-PCR analysis. The isolated EVs exhibited stem cell and CK18 positivity, implying that their source cells were MCs that had undergone mesothelial mesenchymal transition. The EVs were successfully internalized by pFBs and reduced their PDGF-induced proliferation, TGF-β induced collagen accumulation, and EGF-induced migration as shown by various functional assays.
Conclusion: Due to the potential antifibrotic properties exhibited by these extracellular vesicles (EVs), they could hold therapeutic promise. Nevertheless, further in vivo testing is required to substantiate this hypothesis.
Funding: NKFIH K-142728, K-131594; 2020-1-1-2-PIACI-KFI_2020-00021, Semmelweis University, TKP2021-EGA-24, TKP2021-EGA-31, RRF-2.3.1-21- 2022-00003; HUN-REN, ELKH-POC-2022-024, Development and Innovation Fund, ÚNKP-23-3-I-SE-36, ÚNKP-23-3-I-SE-42, ÚNKP-23-4-II-SE-29, ÚNKP-23-5-SE-15; Hungarian Academy of Sciences, János Bolyai Research Scholarship.