Circ_0047835 Combines with miR-144-3p to Promote the Proliferation, Invasion, Migration, and Fibrosis of TGF-β1-Treated Human Tenon's Capsule Fibroblasts by Upregulating SP1

Purpose: Glaucoma is the leading cause of blindness worldwide with complex pathogenesis. Circular RNAs (circRNAs) play critical roles in various diseases, including glaucoma. The purpose of this study was to investigate the role of circ_0047835 and underlying mechanisms in the development of fibrosis after glaucoma filtration surgery. Methods: Human Tenon's capsule fibroblasts (HTFs) were stimulated using transforming growth factor-beta 1 (TGF-beta 1) to mimic a cellular model of glaucoma in vitro. Cell proliferation was evaluated by Cell Counting Kit-8 (CCK-8) assay and 5-ethynyl-2'-deoxyuridine (EdU) assay. Cell invasion and migration were detected by transwell assay and wound healing assay, respectively. Western blot assay was used to measure protein levels. The expression levels of circ_0047835, microRNA-144-3p (miR-144-3p) and specific protein 1 (SP1) mRNA were determined by real-time quantitative polymerase chain reaction (RT-qPCR). The interaction between miR-144-3p and circ_0047835 or SP1 was confirmed by dual-luciferase reporter assay and RNA Immunoprecipitation (RIP) assay. Results: Circ_0047835 expression was elevated in glaucoma tissues and TGF-beta 1-treated HTFs. Circ_0047835 or SP1 knockdown suppressed the proliferation, migration, invasion, and fibrosis of TGF-beta 1-treated HTFs. MiR-144-3p was a target of circ_0047835, and miR-144-3p inhibition reversed the effects of circ_0047835 knockdown in TGF-beta 1-treated HTFs. Moreover, SP1 was identified as a target of miR-144-3p, and miR-144-3p overexpression weakened TGF-beta 1-induced proliferation, migration, invasion, and fibrosis by targeting SP1 in HTFs. Furthermore, circ_0047835 combined with miR-144-3p to regulate SP1 expression. Conclusion: Circ_0047835 might contribute to fibrosis progression after glaucoma surgery by regulating the miR-144-3p/SP1 axis.