The circRNA0001707/miR-203a-3p/TLR4 regulatory axis drives macrophage polarization in enthesitis of newly diagnosed ankylosing spondylitis.

OBJECTIVES

This study aimed to identify circular RNAs (circRNAs) associated enthesitis in patient with ankylosing spondylitis (AS) and to elucidate the underlying mechanism.

METHODS

A multi-phase study was conducted. In the discovery phase, circRNA microarray analysis was performed on peripheral blood mononuclear cells (PBMCs) isolated from 3 AS patients and 3 healthy controls. Differentially expressed circRNAs were subsequently validated in two stages: an initial pilot verification followed by replication in an expanded cohort. The functional role of hsa_circ_0001707 in macrophage polarization was investigated in vitro using THP-1 cells.

RESULTS

Microarray analysis and subsequent validation showed that AS patients exhibited significantly increased levels of hsa_circ_0001707 and reduced levels of hsa_circ_0075522 in PBMC compared to healthy controls. Stratified analysis revealed that hsa_circ_0001707 expression was significantly upregulated in AS patients with enthesitis compared to those without. Multivariate logistic regression analyses demonstrated that hsa_circ_0001707 was independently associated with enthesitis. In vitro, hsa_circ_0001707 overexpression promoted M1 polarization, increasing the secretion of pro-inflammatory cytokines such as TNF-α, IL-6, and IL-23. Conversely, knockdown of hsa_circ_0001707 showed an opposite effect. Mechanistically, hsa_circ_0001707 acted as a molecular sponge for miR-203a-3p, thereby relieving repression of TLR4. Dual-luciferase assays confirmed direct interactions between miR-203a-3p and both hsa_circ_0001707 and TLR4.

CONCLUSION

This study identifies hsa_circ_0001707 as a novel biomarker for AS-associated enthesitis and suggests its role in promoting macrophage M1 polarization through the miR-203a-3p/TLR4 axis. These findings provide new insights into the pathogenesis of enthesitis and suggest potential therapeutic targets for AS.