Reduced microRNA-5572 in thyroid eye disease orbital fibroblasts promotes fibrosis by targeting F2RL2.

To investigate the role of microRNA-5572 in the regulation of fibrosis in orbital fibroblasts (OFs) derived from patients with thyroid eye disease (TED). Transcriptome sequencing was performed on orbital adipose/connective tissue from patients with mild TED (n = 4), moderate-to-severe TED (n = 4), and healthy controls (n = 4) to identify differences in RNA molecules. miRWalk predicted microRNAs potentially involved in TED fibrosis and identified binding sites between F2RL2 and microRNA-5572, which were subsequently verified by dual-luciferase reporter assay. OFs obtained from patients with TED and healthy control donors were cultured. Quantitative real-time PCR and western blot quantified RNA and protein expression. Immunofluorescence staining detected collagen Ⅰ and α-SMA in orbital adipose/connective tissue. MicroRNA-5572 expression was down-regulated in TED-OFs compared with control OFs (CON-OFs). Functional experiments revealed that microRNA-5572 regulated COL1A1 expression in TED-OFs. Inhibiting microRNA-5572 increased COL1A1 protein expression. Furthermore, microRNA-5572 exerted this regulatory effect in TED-OFs by directly targeting F2RL2. MicroRNA-5572 was down-regulated in TED-OFs. Downregulation of microRNA-5572 directly targets F2RL2, thereby increasing COL1A1 expression in TED-OFs.