IL-9 orchestrates immune regulation through CD39/CD73 dependent metabolic reprogramming

Area of Science:

• Immunology
• Cellular Metabolism
• Molecular Signaling

Background:

• Extracellular adenosine triphosphate (ATP) is crucial in cellular energy and acts as a signaling molecule during inflammation.
• Ectonucleotidases CD39 and CD73 hydrolyze extracellular ATP (eATP) to adenosine, regulating immune responses.
• Interleukin-9 (IL-9) is a cytokine with known roles in immune modulation.

Purpose of the Study:

• To investigate the effect of IL-9 on ATP-adenosine metabolism.
• To determine how IL-9-mediated metabolic changes influence T-cell responses.
• To explore the role of the CD39/CD73 axis in IL-9's immunomodulatory functions.

Main Methods:

• Peripheral blood mononuclear cells (PBMCs) from healthy donors were used.
• Flow cytometry (FC) and ELISA were employed to analyze phenotypic, functional, and metabolic changes.
• Pharmacological inhibition of CD39 and CD73 was utilized to assess mechanistic roles.

Main Results:

• IL-9 upregulated CD39 and CD73 expression, enhancing ATP to adenosine conversion.
• This metabolic shift created an immunosuppressive microenvironment, particularly in regulatory T (Treg) cells.
• IL-9 suppressed pro-inflammatory cytokines, increased anti-inflammatory cytokines, and inhibited T-cell proliferation.
• Inhibition of CD39/CD73 largely reversed IL-9's effects on T-cells.

Conclusions:

• IL-9 acts as a regulator of the CD39/CD73 pathway.
• IL-9 influences immune responses by modulating ATP-adenosine metabolism.
• This pathway is relevant in inflammatory and immune-mediated diseases with dysregulated purinergic signaling.