Plasma exosomes may mediate the development of lupus nephritis in patients with systemic lupus erythematosus.

Background: Lupus nephritis (LN) is the most serious complication of systemic lupus erythematosus (SLE), and plasma exosomes may serve as a bridge. MicroRNAs (miRNAs) are abundant in exosomes, so this study aimed to explore the role of exosome-derived miRNA in the development of LN.

Methods: The publicly available data containing plasma exosomal miRNAs in SLE patients and healthy controls were researched, and differential expression and functional enrichment analysis of exosomal miRNA was conducted. Then, plasma exosomes from SLE patients were extracted, and the accuracy of differential expression and functional enrichment analysis was preliminarily verified. PKH26 dye was used to label exosomes to detect whether exosomes can enter HK2 cells. Evaluation of plasma exosomes impact on cell viability was done by utilizing CCK-8 assay. Flow cytometry was used to measure cell apoptosis.

Results: Plasma exosomes were successfully extracted and identified. Through differential expression analysis of the pulbilic data and subsequent qPCR validation, we observed that miR-20b-5p is overexpressed in plasma exosomes of SLE patients, whereas miR-181a-2-3p is downregulated. Then functional enrichment analysis revealed that these differential miRNAs primarily regulate processes such as apoptosis, autophagy, and inflammation. Then, flow cytometry analysis conducted after co-incubation of plasma exosomes and peripheral blood mononuclear cells confirmed that exosomes can indeed regulate apoptosis. And plasma exosomes can successfully enter HK2 cells without affecting cell activity. In addition, plasma exosomes promote HK2 cell apoptosis and autophagy. Overexpression of miR-181a-2-3p could inhibit HK2 cells apoptosis and upregulate the expression of bcl2, and beclin1. At the same time, a trend towards increased apoptosis rates was observed in HK2 overexpressed miR-20b-5p, although the difference did not reach statistical significance. And miR-20b-5p can enhance the expression of caspase3 and becin1 while suppressing the expression of bcl2 and LC3β.

Conclusion: Our research indicates that the abundant presence of miR-20b-5p and the depletion of miR-181a-2-3p in plasma exosomes of SLE patients may mediate the promotion of apoptosis and autophagy in HK2 cells, thereby causing kidney damage and the development of LN.