Single Cell Sequencing of Myeloid Cells in Human Hypertension

Hypertension is a major modifiable risk factor for death and cardiovascular disease, yet its causes are largely unknown. Monocytes and monocyte-derived dendritic cells (DCs) are activated in hypertension producing cytokines that drive T cell activation. Moreover, DCs from hypertensive mice promote hypertension when adoptively transferred into normotensive mice. The specific human subsets of antigen presenting cells (APCs) that promote human hypertension have yet to be described at a single cell level. We isolated total peripheral blood mononuclear cells (PBMCs) from normotensive (n=5) and hypertensive (n=4) human subjects. We sorted for HLA-DR+ and CD19- cells by magnetic bead separation. Single cell sequencing was performed on a 10x Chromium platform. After performing quality controls, we found a total of 10 clusters that were expressed in both normotensive and hypertensive human subjects. KEGG Pathway analysis on all HLA-DR+ myeloid cells revealed that pathways associated with oxidative phosphorylation, toll-like receptor signaling and interleukin (IL)-17 signaling were increased in hypertensive subjects. Conversely, pathways associated with antigen processing and presentation and cell adhesion molecules were enriched in normotensive subjects. Hypertensive subjects had a significant increase in CD14+ CD36+ monocytes compared to controls (p=0.009). Conversely, CD14+ CD36- monocytes and plasmacytoid DCs were significantly reduced in hypertensive subjects (p=0.002 and p=0.0008, respectively). Of particular interest were a cluster of pro-inflammatory monocytes with expression of CD14 CCL3, IL1B, CD83, TNF, and SGK1. Within this cluster, CXCL8, the gene encoding interleukin (IL)-8, and CCL3 were significantly increased in hypertensive subjects compared to controls (adjusted p value = 3.0E-106 and 2.0E-107 , respectively). Further studies are needed to investigate CXCL8 (IL-8) and its role in myeloid cell activation and human hypertension.