Exosomal miR-122-5p: a potential biomarker for preeclampsia diagnosis independent of exosome isolation and endogenous references

Abstract Objective Preeclampsia is a major cause of maternal, fetal, and neonatal mortality. It is necessary to improve early detection of preeclampsia. This study aimed to explore plasma exosomal miRNAs as potential biomarkers for preeclampsia. Methods In this study, we adopted two commonly used exosome extraction methods—SEC combined with ultrafiltration and the ExoQuick commercial kit—to isolate exosomes from the plasma of patients with preeclampsia and healthy pregnant women, and screened for suitable endogenous reference genes. By applying bioinformatics, we identified differentially expressed miRNAs in the plasma exosomes of patients with preeclampsia and healthy pregnant women, and further confirmed their significance in the clinical diagnosis of preeclampsia. Results By using SEC combined with ultrafiltration (SEC group) and ExoQuick (ExoQuick group) commercial kit exosome separation, we extracted exosomes from the plasma of the preeclampsia group and the normal pregnant women group. MiR-30a and miR-30e−5p was verified as the optimal endogenous reference gene. We screened out 4 miRNAs (miR-122-5p, miR-126-3p, miR-144-3p and miR-451a) from 68 differentially expressed miRNAs for verification. Eventually, it was found that among the exosomes extracted by the two exosome isolation methods, only miR-122-5p was stably upregulated in patients with preeclampsia independently of the exosome extraction methods, which may have potential value for the diagnosis and treatment of preeclampsia. Conclusion In this study, we found that miR-122-5p maintained stable differences in plasma exosomes of patients with preeclampsia under different exosome extraction methods, thereby providing clues for potential biomarkers for the early diagnosis of preeclampsia.