Abstract 19150: DUSP1 is Associated With Map-Kinase Signaling in Antigen Presenting Cells Contributing to Salt-Sensitivity of Blood Pressure

Abstract

Salt sensitivity of blood pressure, a pathological response characterized by a marked increase in blood pressure following salt intake, acts independently of hypertension as a risk factor for cardiovascular morbidities. Our recent research has elucidated a mechanism of sodium entry into antigen presenting cells through epithelial sodium channels (ENaC), which leads to the formation of neoantigen presenting isolevuglandin protein adducts via oxidative stress. Reactive oxygen species present in the cell may impact inflammation response as well as other intracellular pathways, chiefly the MAPK pathway. Previous studies have established an inhibitory connection between the protein-coding phosphatase DUSP1 and MAPKs. We hypothesize that DUSP1 acts as a negative regulator of MAPK signaling pathways involved in the immune response to salt-sensitive hypertension. To test our hypothesis, we isolated human monocytes from healthy participants (N=11) and treated them with either normal (150 mMol/L) or high (190 mMol/L) Na+ for 72 hours in vitro. Analysis of bulk RNA sequence data points to a significant upregulation of DUSP1 in the high salt environments compared to normal salt levels (4339 ± 770.1 vs 2721 ± 546.4 , p=0.0192). We also found that the high salt treatment led to increased expression of ERK1 (HS:2066 ± 184.0 NS:1560 ± 136.7 p= 0.0652), ERK2 (HS:8364 ± 669.8 NS:6256 ± 578.3 p= 0.0281), JNK (HS:1069 + 102.2 NS:792.3 ± 74.85 p= 0.0336), and p38 (HS: 4062 ± 329.0 NS:3010 ± 292.5, p= 0.0336). To study further, we enrolled 9 hypertensive participants who discontinued anti-hypertensive therapy for 2 weeks in an inpatient protocol to phenotype them through rapid salt loading and depletion. Blood pressure was recorded and blood collected at baseline, after salt loading, and after salt depletion and CITE-Seq analysis was performed on isolated PBMCs. After salt loading, we found a negative correlation between both p38 expression and pulse pressure (r= -0.7564 p= 0.0299) and p38 expression and systolic blood pressure (r= -0.8371, p=0.0095). We found a positive correlation between DUSP1 expression and systolic blood pressure after salt depletion (r= 0.7089, p=0.0490). These results suggest that DUSP1 plays an important role in salt sensitivity of blood pressure.