MIAT promotes myofibroblastic activities and transformation in oral submucous fibrosis through sponging the miR-342-3p/SOX6 axis

Oral submucous fibrosis (OSF) is an oral potentially malignant disorder that is closely related to the habit of areca nut chewing. Long non-coding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) has been identified as an essential regulator in the fibrosis progression. However, the role of MIAT in the development of OSF remains unknown. The transcriptomic profile showed that MIAT is significantly overexpressed in the OSF cohort, with a positive correlation to fibrotic markers. The silencing of MIAT expression in primary buccal mucosal fibroblasts (BMFs) markedly inhibited arecoline-induced myofibroblast transformation. Mechanistically, MIAT functioned as a miR-342-3p sponge and suppressed the inhibitory effect of miR-342-3p on SOX6 mRNA, thereby reinstating SOX6 expression. Subsequent RNA expression rescue experiments confirmed that MIAT enhanced resistance to apoptosis and facilitated myofibroblastic properties such as cell mobility and collagen gel contraction by regulating the miR-342-3p/SOX6 axis. Taken together, these results suggest that the abnormal upregulation of MIAT is important in contributing persistent activation of myofibroblasts in fibrotic tissue, which may result from prolonged exposure to the constituents of areca nut. Furthermore, our findings demonstrated that therapeutic avenues that target the MIAT/miR-342-3p/SOX6 axis may be a promising approach for OSF treatments.