Abstract 056: Transcriptomic Changes In Individual Cell Types Of The Arcuate Nucleus In The Mouse Deoxycorticosterone-acetate (doca)-salt Model Of Hypertension

Abstract

Low-renin hypertension is common among the elderly, subjects of black African ancestry, those with heart or renal failure, and women with preeclampsia. Increased understanding of the causes and consequences of low-renin hypertension is necessary for the development of new efficacious and personalized therapeutics. One commonly employed preclinical model is “DOCA-salt” (DOCA), which causes robust hypertension, proteinuria, and organ damage. The arcuate nucleus of the hypothalamus (ARC) has been implicated in control of metabolic rate and blood pressure responses to DOCA. To characterize the DOCA related changes within the ARC, we used single nucleus RNA sequencing (snRNA-Seq) to individually interrogate the transcriptomes of numerous mouse ARC cell types. Male C57BL/6J mice 7 weeks-of-age underwent sham surgery or subcutaneous implantation of a 50mg DOCA pellet. All mice had water; DOCA mice were also provided 0.15 M NaCl drink ad libitum. Body composition was assessed by nuclear magnetic resonance. After 3 weeks, tissues were weighed and blood chemistries assessed. Features of DOCA treatment were consistent with previous studies, such as suppressed growth trajectory (sham n=7, DOCA n=8; -0.8±0.4g/3wk; p<0.01). Nuclei were isolated from ARC punches for snRNA-seq. Thirty-two unique cell type clusters were identified from snRNA-Seq, and DOCA differential gene expression (DEG) was determined using MAST. Two clusters were classified as resting (Cluster 23: DEGS up=11, down=35) and activated (Cluster 25: DEGS up=45, down=169) microglia subtypes. Analysis of proportions suggests there are fewer activated microglia in the DOCA ARC (dataset Sham=25%, DOCA = 75%; Cluster 25 Sham=37%, DOCA=63%; χ2 p = 0.0056), and DOCA may negatively impact activated microglia functions through decreased calcium signaling and netrin receptor activity. Sub-clustering of neuropeptide clusters resulted in the identification of 3 Agouti-related peptide sub-clusters. DOCA DEG enrichment terms indicated decreased neurotransmitter uptake, altered GABA synapse functions, and changed hormone secretion in the sub-clusters, respectively. These data provide novel insights into cell-specific molecular changes occurring in the ARC due to DOCA-salt hypertension.