Isoquercitrin promotes hair growth through induction of autophagy and angiogenesis by targeting AMPK and IGF-1R

Background: Hair follicles play a crucial role in hair growth, wound healing, thermoregulation, and sebum production. Hair loss affects millions of people worldwide, yet therapeutic options for managing hair loss and pattern baldness are limited. Isoquercitrin (IQ), a natural small molecule from drinkable Chinese tea, is famous for anti-aging properties.

Purpose: This study aimed to explore the potential of IQ in treating and preventing hair loss, along with its underlying mechanisms.

Methods: The adult male and female, as well as middle-aged female sprague dawley (SD) rats were used to conduct hair growth experiments in vivo. Signaling pathways and target protein identification were analyzed through western blotting, drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA) and surface plasmon resonance (SPR) analyses. Further, the targets were confirmed through in vivo inhibition experiments.

Results: IQ is reported here to stimulate anagen phase initiation and hair regrowth by directly interacting with adenosine 5'-monophosphate-activated protein kinase (AMPK) and insulin-like growth factor 1 receptor (IGF-1R). This process involves the AMPK/mammalian target of rapamycin (mTOR)/ unc-51-like autophagy-activating kinase 1 (ULK1) signalling pathway to trigger autophagy and the IGF-1R/phosphatidylinositol 3-kinase (PI3 K)/protein Kinase B (AKT), vascular endothelial growth factor (VEGF)/ vascular endothelial growth factor receptor (VEGFR)/ angiotensin (ANG) pathways to promote angiogenesis in female rats. Furthermore, the hair regrowth efficacy of IQ in adult male rats and middle-aged female rats was verified and shown. Similarly, our findings indicate that IQ promotes hair regrowth in middle-aged rats through autophagy and angiogenesis, akin to its effects in adult rats.

Conclusion: AMPK and IGF-1R proteins are identified as the target proteins of IQ and the AMPK/mTOR/ULK1, IGF-1R/PI3K/AKT and VEGF/VEGFR/ANG signalling pathways take important roles in hair growth effect of IQ. Thus, these signaling pathways are crucial for developing future treatments and clinical strategies for hair regeneration.