Zidi Xu,1,* Chang Li,2,* Xueyi Liu,3 Yongting Zhou,3 Yingbo Zhang,3 Jie Wang,3 Hao Wu,3 Abdullah Al-danakh,4 Yixuan Peng,3 Zhibo Xiao3 

1Department of Medical Cosmetology, the Second Affiliated Hospital of Xi an Medical University, Xi ‘an,People’s Republic of China; 2Shenzhen Pingshan Central Hospital, Shenzhen, People’s Republic of China; 3Plastic Surgery Department, The Second Affiliated Hospital of Harbin Medical University, Harbin, Peoples Republic of China’; 4Department of Urology, the First affiliated hospital of Dalian Medical University, Dalian, Liaoning, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Zhibo Xiao, Email 137985805@qq.com

Background: Recent evidence suggests a crucial biological role for Circular RNAs (circRNAs) in keloid diseases, yet the underlying mechanisms remain unclear. This study explored the biological effects and molecular mechanisms of hsa_circ_0002198 in keloid formation.
Methods: Real-time quantitative PCR (qRT-PCR) was employed to assess the expression of circ_0002198 in keloid tissues, normal skin tissues, keloid fibroblasts (KFs), and normal skin fibroblasts (NFs) from nine patients. To investigate the role of circ_0002198 in keloid pathogenesis, cell transfection technology was utilized to knock down circ_0002198. Various experiments including Cell Counting Kit-8 (CCK-8), 5-Ethynyl-2′-deoxyuridine (EdU), Transwell, wound healing assay, flow cytometry, and others were conducted to explore the potential mechanisms associated with circ_0002198 expression. The RNA-binding protein Eukaryotic translation initiation factor 4A, isoform 3 (EIF4A3) binding to circ_0002198 was identified and confirmed through bioinformatics databases prediction and RNA immunoprecipitation (RIP) assay. Finally, the expression of EIF4A3 was assessed, and both silencing and overexpression were employed to verify its role in circ_0002198 regulation.
Results: The expression levels of circ_0002198 and EIF4A3 were notably elevated in keloid tissues and KFs compared to normal skin tissues and NFs. The reduction of circ_0002198 expression in KFs significantly impeded their proliferation, migration, and invasion. It also hindered the cell cycle process and the expression of associated proteins while concurrently promoting apoptosis in KFs. EIF4A3 was identified to bind to the flanks of circ_0002198, enhancing the occurrence of circ_0002198 and its role in regulating the progression of KFs.
Conclusion: Our study offers insights into how Circular RNA may contribute to the pathogenesis of keloid formation, highlighting Circ_0002198 as a potential novel biomarker for keloids in association with EIF4A3. Further research, involving larger study cohorts, is necessary to broaden our understanding of keloid mechanisms and potential treatment approaches.

Keywords: keloid, circular RNA, fibroblasts, hsa_circ_0002198, EIF4A3, cell cycle