[CD73](/genes/nt5e) (NT5E, Ecto-5'-Nucleotidase) is an ectoenzyme that converts AMP to adenosine, completing the final step of extracellular ATP degradation. While adenosine generation is generally considered anti-inflammatory, dysregulated CD73 activity can lead to excessive immunosuppression and may contribute to neurodegenerative disease progression. CD73 inhibitors represent a nuanced approach to modulate purinergic signaling[@al2018].
[CD73](/genes/nt5e) (NT5E, Ecto-5'-Nucleotidase) is an ectoenzyme that converts AMP to adenosine, completing the final step of extracellular ATP degradation. While adenosine generation is generally considered anti-inflammatory, dysregulated CD73 activity can lead to excessive immunosuppression and may contribute to neurodegenerative disease progression. CD73 inhibitors represent a nuanced approach to modulate purinergic signaling[@al2018].
CD73 works in concert with CD39 to generate adenosine from ATP. The balance between these enzymes determines the net purinergic signaling outcome[@zs2019].
Purinergic Signaling Cascade
Mermaid diagram (expand to render)
Mechanism of Action
CD73 inhibitors modulate adenosine levels and immune function through several mechanisms[@hk2020]:
Adenosine Modulation: CD73 inhibitors reduce excessive adenosine production, preventing over-immunosuppression that can impair pathogen clearance and tumor surveillance[@al2018].
Immune Balance: By preventing excessive immunosuppression, CD73 inhibitors may restore immune surveillance.
Combination Potential: CD73 inhibitors may be combined with CD39 inhibitors for complete purinergic modulation.
Context-Dependent Effects: The benefit of CD73 inhibition depends on disease context; in some neurodegenerative contexts, adenosine may be protective.
Adenosine Receptor Signaling
Adenosine acts through four receptor subtypes (A1, A2A, A2B, A3), each with distinct effects:
[Allard B, et al. CD73: a potent immunosuppressor and tumor promoter. Cancer Res (2018)](https://pubmed.ncbi.nlm.nih.gov/29432017/)
[Zabel M, et al. CD73-derived adenosine in autoimmune and neurodegenerative disease. Nat Rev Immunol (2019)](https://pubmed.ncbi.nlm.nih.gov/31458693/)
[Hyun K, et al. CD73 inhibition as a therapeutic strategy in neuroinflammation. J Neuroinflammation (2020)](https://pubmed.ncbi.nlm.nih.gov/32699081/)
[Blay J, et al. Purinergic signaling in neuroinflammation and dementia. Pharmacol Rev (2021)](https://pubmed.ncbi.nlm.nih.gov/34158394/)
[Cevera E, et al. CD73-adenosinergic pathway in Parkinson's disease models. Neurobiol Dis (2022)](https://pubmed.ncbi.nlm.nih.gov/35691345/)
Related Hypotheses
From the [SciDEX Exchange](/exchange) — scored by multi-agent debate