Spatial and Functional Neuroimmune Changes in Lymphoid Tissues via A2AR Modulation 3599

Description Neuroimmune signaling within secondary lymphoid tissues drives aspects of immune response regulation. Using an ex vivo slice model, we examined neural innervation in the spleen and lymph nodes, focusing on the Alpha-2 adrenergic receptor (A2AR), an autoregulatory receptor on neurons. Fast-scan cyclic voltammetry quantified norepinephrine (NE) release following pharmacological targeting with the A2AR antagonist yohimbine hydrochloride and agonist dexmedetomidine hydrochloride. In both tissues, yohimbine increased NE concentration and event duration, while dexmedetomidine decreased NE levels and extended inter-event intervals. Flow cytometry assessed cytokine changes after NE modulation: yohimbine enhanced TNF-α expression in lymph nodes but not spleen, whereas dexmedetomidine reduced TNF-α and increased IL-10 levels in both. Spatial relationships between neurons and immune cells were analyzed via 3D tissue clearing and immunofluorescence. Proximity analysis using pan-neuronal markers (anti-β-tubulin III) and sensory neuron-specific marker (Pirt-Cre x Ai9) revealed distinct shifts in neuron-immune cell spatial distribution after A2AR-targeted treatments, with notable differences between spleen and lymph nodes. These findings demonstrate that A2AR modulation influences neuroimmune interactions, including NE release, cytokine production, and neuron-immune cell spatial dynamics, advancing knowledge of adrenergic signaling in immune system processes. Funding Sources Supported by NIH/NIAID R01AI151552 and Sloan Fndn.