CD73-derived adenosine controls inflammation and neurodegeneration by modulating dopamine signalling

Area of Science:

• Neuroscience
• Biochemistry
• Immunology

Background:

• Increased adenosine A2A receptor (A2AR) signaling is observed in Parkinson's disease (PD), but its source is unclear.
• Extracellular ATP catabolism by ectonucleotidases regulates adenosine levels.
• Ecto-5'-nucleotidase (CD73) is a key enzyme in adenosine production.

Purpose of the Study:

• To investigate the role of CD73-mediated adenosine formation in Parkinson's disease pathogenesis.
• To determine how CD73-derived adenosine influences microglial immune responses and neuroinflammation.
• To explore the therapeutic potential of targeting CD73 in PD.

Main Methods:

• Utilized 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and laser injury models of PD.
• Assessed microglial responses to CD73 inactivation and adenosine receptor activation.
• Measured dopaminergic neuron viability and motor behavior in PD models.
• Investigated the interplay between adenosine and dopamine signaling in microglia.

Main Results:

• Upregulated CD73 and A2AR were found in MPTP-induced PD models, correlating with elevated adenosine signaling.
• CD73 inactivation attenuated pro-inflammatory responses in microglia but enhanced their dynamic functions.
• Limiting CD73-derived adenosine suppressed neuroinflammation, improved dopaminergic neuron survival, and restored motor function.
• CD73 inactivation reduced A2AR induction and pro-inflammatory signaling, which was reversed by adenosine analogues.
• A2A receptor activation enhanced inflammation by antagonizing dopamine-mediated anti-inflammatory effects.

Conclusions:

• CD73-derived adenosine signaling via A2AR plays a critical role in modulating microglial immunoresponses and neuroinflammation in Parkinson's disease.
• Targeting CD73 to reduce adenosine production presents a promising therapeutic strategy for Parkinson's disease by mitigating neuroinflammation.