Background: Plasma extracellular vesicles (EVs) are elevated in primary Sjögren’s syndrome (pSS) patients, whose function remains unclear.

Objectives: To explore the potential function of plasma EVs on T cell dysregulation in pSS.

Methods: Plasma EVs from pSS patients or healthy controls (HCs) were isolated, characterized, and quantified using transmission electron microscope, nanoparticle tracking analysis, flow cytometry, western blotting, BCA protein assay, and ELISA. pSS naïve CD4 ⁺ T cell activation and differentiation treated with EVs isolated from equal volumes of pSS or HC plasma were examined using flow cytometry. miRNA expression profiles of pSS and HC plasma EVs were determined using microRNA (miRNA) sequencing, and upregulated miRNAs in pSS plasma EVs were transfected to naïve CD4 ⁺ T cells, which were examined with activation and differentiation. RNA sequencing of miRNA-transfected naïve CD4 ⁺ T cells combined with miRNA target prediction algorithm identified miRNA target genes, which were confirmed by dual luciferase reporter assay. Tfh cell differentiation of naïve CD4 ⁺ T cells transfected with miRNA and target gene-expressing vector were analyzed using flow cytometry.

Results: pSS plasma contained more EVs than HC plasma (Figure 1A and B). pSS plasma EVs promoted CD4 ⁺ T cell activation, Th1 and follicular T helper (Tfh) differentiation (Figure 1C and E). miR-501-3p were enriched in pSS plasma EVs (Figure 2A), and promoted CD4 ⁺ T cell activation and Tfh differentiation (Figure 2B and C). Special AT-rich sequence-binding protein-1 (SATB1) was downregulated by miR-501-3p (Figure 2D–E), and overexpressing SATB1 reversed Tfh differentiation promoted by miR-501-3p (Figure 2F).

Conclusion: Plasma EVs are elevated and promote T cell activation and Tfh differentiation in pSS. pSS plasma EVs contains more miR-501-3p, which downregulates SATB1 to promote Tfh differentiation in pSS (Figure 2G).

REFERENCES: NIL.

Figure 1.

Elevated plasma extracellular vesicles (EVs) in primary Sjogren’s syndrome (pSS) promote CD4 ₊ T cell activation, Th1 and Tfh differentiation.

Figure 2.

Upregulated miR-501-3p in pSS plasma EVs promotes CD4 ⁺ T cell activation and Tfh cell differentiation through downregulating SATB1.

Acknowledgements: NIL.

Disclosure of Interests: None declared.