Th172 - Vagus Nerve Stimulation Alters Circulating Ly6clow Monocyte Populations

Aisling Tynan – Feinstein Institutes for Medical Research; Carlos Bravo Iñiguez – Feinstein Institutes for Medical Research; Kevin Tracey – Feinstein Institutes for Medical Research; Sangeeta Chavan – Feinstein Institutes for Medical Research

Abstract Text: Neuronal pathways, including the vagus nerve-based inflammatory reflex, are physiological regulators of immune function and inflammation. Electrical vagus nerve stimulation (VNS) regulates tumor necrosis factor production in the spleen by a mechanism requiring acetylcholine signaling through the α7 nicotinic acetylcholine receptor expressed on cytokine-producing macrophages. While it is understood that VNS attenuates the release of proinflammatory cytokines from splenic macrophages, its effects on the immune cell populations are not yet clear.
Here, we subjected mice to electrical VNS for four minutes at a continuous current of 250 uA and 16.5 ms pulse width at 30 Hz. Two hours following stimulation, whole blood mononuclear cells were isolated and processed for single-cell RNA sequencing (scRNASeq) as per 10X Genomics standard single-cell protocol. Samples were sequenced using NextSeq 2000 and analyzed utilizing the Seurat platform. Analysis of the scRNASeq data from sham (n = 12,030 cells) and VNS treated (n=10,057) samples identified 12 unique clusters based on annotated canonical markers and the Immgen database. Further investigation of the monocyte cluster using differential genes identified significant (log fold change > 2, and an adjusted p-value < 0.05) downregulation of the following genes: Wfdc21, Adgrl3, and S100a8. Within monocytes, we observed an increase in anti-inflammatory Ly6clow monocytes when comparing sham (n=7,538 cells) and VNS-treated (n=2,971 cells) cells. Overall, this study highlights the importance of investigating the complex interplay between the nervous and the immune systems and underscores the systemic changes that occur during vagus nerve stimulation.