Graduate Student University of Cincinnati Cincinnati, Ohio, United States
Disclosure(s):
Kaejaren Caldwell, BS: No financial relationships to disclose
Introduction/Rationale: Astrocytes are central regulators of the CNS, integrating metabolic and inflammatory cues to orchestrate neuroimmune responses. During neuroinflammation, they adopt a reactive phenotype with morphological remodeling, altered cytokine release, receptor reorganization, and oxidative signaling. While adenosine’s immunoregulatory roles are well studied, its analog guanosine remains enigmatic. This study investigates how guanosine modulates astrocyte reactivity via purinergic receptor engagement and PI3K/AKT signaling.
Methods: Primary astrocytes were stimulated with LPS (100 ng/mL) and IFN-γ (20 ng/mL). Guanosine (100 μM) was applied concurrently or post-stimulation. Cytokine secretion (IL-1β, TNF-α, IL-10) was quantified via ELISA. Immunocytochemistry and western blotting assessed adenosine receptor (A1R, A2AR) expression, ENT1/ENT2 regulation, and PI3K/AKT activation. PI3K inhibitors probed pathway dependence. Ongoing FSCV experiments monitor real-time extracellular purine flux in reactive astrocytes.
Results: Preliminary data suggest guanosine reshapes the cytokine landscape of LPS/IFN-γ–stimulated astrocytes, attenuating proinflammatory signaling while enhancing IL-10 secretion. Purinergic receptor expression appears rebalanced following guanosine treatment, with increased AKT activation, consistent with pathway engagement. FSCV measurements reveal shifts in extracellular purine release between naïve and stimulated astrocytes, supporting guanosine’s regulatory role. Integration with morphological assessments underscores its neuroprotective potential.
Conclusion: These findings suggest guanosine reprograms reactive astrocytes toward an anti-inflammatory phenotype through purinergic PI3K/AKT dynamics. By modulating cytokine output and recalibrating receptor networks, guanosine fine-tunes CNS immune tone. This work uncovers a novel axis linking purine metabolism to neuroinflammatory regulation, positioning guanosine as a compelling mediator of astrocyte-driven neuroinflammation.
