Astragaloside IV inhibits retinal pigment epithelial cell senescence and reduces IL-1β mRNA stability by targeting FTO-mediated m6A methylation

Abstract

Background

Resistance to senescence in retinal pigment epithelial (RPE) cells can delay the progression of age-related macular degeneration (AMD). However, the mechanisms underlying RPE cell senescence remain inadequately understood, and effective therapeutic strategies are lacking. While astragaloside IV (Ast) has demonstrated anti-aging properties, its specific effects on RPE cell senescence and potential mechanisms are not yet fully clarified.

Purpose

This study aimed to explore the impacts of Ast on RPE cell senescence and to uncover the molecular mechanisms involved.

Methods

The therapeutic efficacy of Ast was assessed using sodium iodate (NaIO₃)-induced adult retinal pigment epithelial cell line 19 (ARPE-19) cell models and an AMD mouse model. To investigate the mechanisms by which Ast mitigated RPE cell senescence, RNA sequencing (RNA-seq), drug affinity responsive target stability-mass spectrometry (DARTS-MS), cellular thermal shift assay (CETSA), reverse transcription quantitative PCR (RT-qPCR), as well as western blotting were conducted.

Results

Ast significantly inhibited NaIO₃-treated ARPE-19 cell senescence and protected against NaIO₃-induced AMD in mice. RNA-seq analysis revealed that Ast significantly attenuated inflammation-related signaling pathways and reduced the mRNA levels of interleukin-1 beta (IL-1β). Specifically, Ast decreased the stability of IL-1β mRNA while enhancing its N6-methyladenosine (m⁶A) methylation. Furthermore, Ast directly interacted with fat mass and obesity-associated protein (FTO). Knockdown or pharmacological inhibition of FTO mitigated the senescence and IL-1β expression in NaIO₃-treated ARPE-19 cells. FTO was essential for Ast to inhibit cellular senescence and IL-1β expression. Additionally, inhibition or knockdown of FTO conferred also provided resistance to AMD in the murine model.

Conclusion

Our results indicated that Ast significantly attenuated RPE cell senescence and showed anti-AMD properties. FTO was demonstrated to be a promising therapeutic target for AMD treatment. These findings may provide a deeper understanding of the molecular mechanisms underlying RPE cell senescence in AMD and offer potential strategies for its prevention and management.