Characterization of serum extracellular vesicles and their differential level of miR-197-3p in familial Mediterranean fever patients

Abstract

Objectives

The aim of this study was to analyze the existence of miRNAs derived from serum extracellular vesicles (EVs) in familial Mediterranean fever (FMF) patients. Our group has previously shown the association of certain miRNAs with FMF.

Methods

Serum samples of adult and pediatric FMF patients and their age matched controls were used in the study. Serum EVs were characterized by transmission electron microscopy (TEM) and flow cytometry. RNAs were isolated from EVs and levels of miR-197-3p and miR-20a-5p were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

EV characterization using TEM demonstrated fraction of 30–120 nm-sized particles with cup-shaped morphology. Flow cytometry results revealed the CD63 and CD81 positive populations as 53.3% in serum EVs. We showed that miR-197-3p and miR-20a-5p were “circulating miRNAs” and carried in EVs of FMF patients and controls. In FMF patients, level of miR-197-3p was significantly decreased. There was no significant alteration in the level for miR-20a-5p between patients and controls.

Conclusion

We showed the differential level of miR-197-3p in serum EVs of the FMF patients. miR-197-3p’s potential as a biomarker and therapeutic target in FMF pathogenesis warrants further investigation.

Key Points

• EVs and EV-miRNAs can be identified in FMF patients’ sera.

• Serum EV-miR-197-3p is dysregulated in FMF patients.

• Serum EV-miR-197-3p might have both diagnostic and therapeutic potentials.

Keywords:

• Familial Mediterranean fever
• extracellular vesicles
• miRNAs
• transmission electron microscopy
• flow cytometry

Author contributions

ZT was involved in the study design, experiments related to extracellular vesicles and miRNAs, analysis, and interpretation of data. YZAU and THA were involved in the study design and interpretation of the data. SO and OK recruited the patients and controls and provided the necessary blood samples. NY and PK were responsible for the transmission electron microscopy experiments. UH and GE did the flow cytometry experiments and data analysis. BBP was involved in the study design, interpretation of data, and supervision of this study. All authors read and approved the final manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Code availability statement

Not applicable.

Data availability statement

All data generated or analyzed during this study are included in this published article [and its Supplementary Information files].

Additional information

Funding

This work was supported by Hacettepe University Scientific Research Coordination Unit (Project Number: THD-2017-16316).