Artemisinin alleviates Parkinson's disease by targeting Adcy5-Gch1 axis to trigger a cascade generation of BH4 and dopamine in rats.

Background: Parkinson's disease is a highly prevalent neurodegenerative disorder. Hyposecretion of dopamine (DA) is the end result in the pathology of Parkinson's disease. Unfortunately, safe and efficient therapeutic drugs are deficient. Tyrosine hydroxylase is the rate-limiting enzyme for DA synthesis, could hydroxylate tyrosine and generate levodopa with tetrahydrobiopterin (BH4) as an indispensable coenzyme. Furthermore, BH4 was confirmed to confer neuroprotection against Parkinson's disease. Thus, regulation of BH4 synthesis was verified to become a promising therapeutic strategy for Parkinson's disease.

Results: We demonstrate that artemisinin effectively produced neuroprotection against Parkinson's disease in rats. Integrated analysis of midbrain proteomics and non-targeted metabolomics suggests that artemisinin might target adenylate cyclase 5 (Adcy5) to increase GTP cyclohydrolase 1 (Gch1, BH4 synthetase) expression to further boost BH4 synthesis. To verify this hypothesis, molecular docking experiments demonstrate that ART could directly bind to Adcy5. Artemisinin increases Adcy5 and Gch1 expressions and BH4 production both in vivo and in vitro. Further rescue experiments demonstrate that artemisinin-generated DA neuroprotection and hypersecretion of DA and BH4 disappears after inhibition of Adcy5 or Gch1 in vitro. Additionally, suppression of Adcy5 aggravates Parkinson's disease manifestation, decreases midbrain DA and BH4 production and down-regulated Gch1 expression in vivo.

Conclusions: Artemisinin mediates neuroprotection against Parkinson's disease via regulation of Adcy5-Gch1-BH4 axis in rats. These findings present a beneficial potential for future application of artemisinin on Parkinson's disease treatment.