Autoantigen-targeting microRNAs in Sjögren’s syndrome

MicroRNAs are short endogenous non-coding RNAs that regulate gene expression in various physiological and pathological conditions. To characterize autoantigen-targeting microRNAs in Sjögren’s syndrome (SS), a systematic study was carried out, in which a candidate microRNA set was first identified by bioinformatics analysis and literature search. Then, their gene silencing activities were evaluated with fusion reporter gene and endogenous targets, leading to the identification of three microRNAs: TRIM21-targeting miR-1207-5p, TRIM21-targeting miR-4695-3p, and La autoantigen-targeting miR-299-5p. Compared to healthy controls, downregulation of miR-1207-5p and miR-4695-3p expression was further revealed in the minor salivary glands of primary SS (pSS) patients. This, on the one hand, characterized two autoantigen-targeting microRNAs in Sjögren’s syndrome and, on the other hand, suggested that downregulation of miR-1207-5p and miR-4695-3p expression may lead to increased TRIM21 levels in the minor salivary glands, which contributes to the development of Sjögren’s syndrome.