MiR-223-3p Aggravates Ocular Inflammation in Sjögren’s Syndrome

Background and Objectives: Sjogren’s syndrome (SS) is a chronic autoimmune disease, particularly involving the lacrimal and salivary glands, with dryness as the main symptom. To date, the pathogenesis of SS is not fully understood. Recently, numerous miRNAs were implicated in SS etiology and pathogenesis. Methods: Ocular wash was collected from SS patients and healthy controls. INF-γ-treated salivary gland epithelial cells (SGECs) were utilized as SS in vitro models. Expressions of miR-223-3p and inositol 1,4,5-trisphosphate receptor type 3 (ITPR3) in ocular wash specimens and cells were measured by RT-qPCR assay and western blot analysis, respectively. ELISA assay was exploited to detect IL-6, IL-12, and TNF-γ levels. CCK-8, flow cytometry, and western blot assay were exploited to determine cell viability, apoptosis, and apoptosis-related protein levels. Results: ITPR3 was a direct downstream gene of miR-223-3p and negatively modulated by miR-223- 3p. MiR-223-3p increased while ITPR3 decreased in samples from SS patients and INF-γ-induced SGECs. miR-223-3p knockdown facilitated INF-γ-induced SGECs cell viability and restrained apoptosis and inflammation response through the NF-ΚB pathway. Conclusion: MiRNA-223-3p is implicated in the process of SS initiation and development. It may become one of the targets for the treatment of SS in the future, as well as a possible indicator for clinical monitoring of disease activity.