Targeting microRNA-190a halts the persistent myofibroblast activation and oxidative stress accumulation through upregulation of Krüppel-like factor 15 in oral submucous fibrosis.

Background/purpose: Oral submucous fibrosis (OSF) is a condition characterized by inflammation and excessive collagen deposition, which has been identified as a potentially malignant disorder. Recently, several microRNAs (miRNAs) have been shown to be implicated in various disorders associated with fibrosis. However, how these miRNAs modulate OSF development is poorly understood. Therefore, the study aimed to identify the specific miRNAs that contribute to the progression of OSF and to investigate their molecular mechanisms in promoting fibrosis. Materials and methods: The expression and clinical significance of potential pro-fibrosis miRNA in the OSF cohort and primary buccal mucosal fibroblasts were confirmed through RNA sequencing and qRT-PCR. Luciferase reporter activity assay, miRNA mimic or inhibitor, and short-hairpin RNA silencing were used to elucidate the molecular mechanism of miRNA. Transwell migration, collagen contraction, and reactive oxygen species (ROS) generation detection were used to investigate the effects of this mechanism on the myofibroblast phenotype and cellular pro-fibrosis capacity. Results: This study demonstrated that miR-190a was overexpressed in fibrotic buccal mucosal fibroblasts (fBMFs). Transfecting fBMFs with miR-190a inhibitor resulted in reduced cell migration, collagen gel contraction, ROS generation, and expression of fibrotic markers. Furthermore, miR-190a exerted this pro-fibrosis property by direct binding to its target, Krüppel-like factor 15 (KLF15). The results also indicated that the aberrant upregulation of miR-190a, in turn, downregulated the expression of KLF15, which resulted in the activation of myofibroblast. Conclusion: Our findings demonstrated that miR-190a was involved in myofibroblast activation, suggesting that targeting the miR-190a/KLF15 axis may be a feasible approach in the therapy of OSF.