Abstract P189: Human Endothelin-1 Overexpression in Mice Changed Gene Expression in Mesenteric Arteries

Abstract

Background: Transgenic mice with tamoxifen-inducible endothelium-restricted human endothelin-1 overexpression (ieET-1) exhibited blood pressure (BP) elevation for 3 weeks or 3 months after induction. Vascular injury was observed only after 3-month exposure to human ET-1 overexpression. It is unknown whether 3-week or 3-month exposure to ET-1 overexpression results in gene dysregulation. We aimed to identify differentially expressed (DE) microRNAs (miRs) and genes in mesenteric arteries (MAs) of ieET-1 mice after 3-week and 3-month induction of human ET-1 overexpression. Methods: Ten to 12-week-old male ieET-1 mice and control ieCre mice expressing a tamoxifen-inducible Cre recombinase under the control of endothelium-specific Tie2 promoter were treated with tamoxifen (1 mg/kg/day, s.c.) for 5 days and sacrificed 16 days or 3 months later. RNA was extracted from MAs of ieCre and ieET-1 mice for small and total RNA-sequencing using Illumina HiSeq-2500 and further studied using a systems biology approach. DE genes were identified with fold change >1.4 and P <0.005. DE genes were validated using another set of mice and type of vascular cells expressing them by reverse transcription-quantitative PCR (RT-qPCR). Results: No DE miR were detected, while DE genes were identified after 3-week (15↑ and 39↓) and 3-month exposures to human ET-1 overexpression (4↑and 3↓). RT-qPCR validated 3 of 7 3-month DE genes: Khdrbs3 (KH domain containing, RNA binding, signal transduction associated 3), Aqp1 (Aquaporin 1) and Ly6e (Lymphocyte antigen 6 complex locus E). Khdrbs3 was increased and Ly6e decreased after 3-week and 3-month exposures to human ET-1 overexpression, while Aqp1 was increased only after 3-month exposure. In mice, Khdrbs3 and Ly6e were expressed in endothelial cells (ECs), smooth muscle cells (SMCs) and fibroblasts (FCs) and Aqp1 was more expressed in ECs and FCs. In humans, KHDRBS3 was expressed in the 3 vascular cell types, LY6E more in FCs, and AQP1 more in ECs. Conclusions: Exposure for 3 weeks and 3 months to endothelial human ET-1 overexpression changed the expression of Khdrbs3, Ly6e and Aqp1 in MAs. Vascular cells expressing these genes were identified. However, their role in ET-1-induced vascular injury remains to be determined.