Screening and identification of Kringle 5-inhibitory microRNAs from Astragali radix decoction pieces using...

This study presents a groundbreaking investigation into the molecular interaction between microRNAs (miRNAs) from the traditional Chinese medicine Astragali Radix and the anti-angiogenic protein Kringle 5 (K5). We successfully screened and identified 10 highly enriched miRNAs that exhibit a significant binding affinity to K5. Through a combination of bioinformatics and experimental techniques, including molecular docking and affinity chromatography, we found that specific miRNAs, particularly miR1, act as natural aptamers, binding to K5 with high selectivity and an association constant (K_a) of approximately 5.80 × 10⁴ L/mol. Our findings reveal that the conserved stem-ring structure of these miRNAs is crucial for their recognition and binding to K5, mediated by electrostatic, hydrophobic, and hydrogen bond interactions. Functional assays in vitro demonstrate that miR1 effectively neutralizes K5-mediated inhibition of endothelial cell proliferation and restores the HIF-1α/VEGF signaling pathway. This research provides a novel biochemical perspective suggesting that Astragalus-derived miRNAs may function as natural molecular decoys to modulate K5 activity, thereby supporting angiogenesis. These findings offer new insights into the bioactive landscape of traditional Chinese medicine and providing a strong foundation for the development of novel nucleic acid-based drugs.