PS-B12-3: ANGIOTENSIN II CAUSED ACTIVATED DNKT CELL EXPANSION IN MESENTERIC VESSEL PERIVASCULAR ADIPOSE TISSUE OF MALE MICE

Abstract

Objective: We have demonstrated that γΔ T cells, which are an innate-like T cell subset mostly found in tissues, play a role in hypertension. We showed that angiotensin (AngII) II-induced γΔ T cell expansion in perivascular adipose tissue (PVAT), hypertension and mesenteric artery endothelial dysfunction that were blunted in mice deficient in γΔ T cells. We hypothesized that single cell RNA sequencing (scRNA-seq) would reveal γΔ T cell subpopulations in PVAT involved in hypertension, vascular injury and T cell activation. Design and method: Male C57BL/6J mice were infused SC or not with 490 ng/kg/min AngII for 14 days (n = 3). Hypertension was confirmed by tail cuff blood pressure measurement. Mesenteric vessels (MV) with PVAT were collected, lymph nodes removed, single cell suspension obtained, samples labeled with hashtag antibodies, T cells isolated by fluorescence-activated cell sorting, the 6 samples pooled in one tube, scRNA libraries prepared with a Chromium Next GEM Single Cell 3 Reagent Kit. Sequencing was done on an Illumina Novaseq 6000, and sequences were mapped to mouse genome mm10–2020-A, data analysed using Cell Ranger pipeline and Seurat in R. Gene ontology (GO) term enrichment analysis done by Cytoscape. Cell subpopulations were validated by flow cytometry using a BD LSR Fortessa cell analyzer and data analyzed using FlowJo software. Results: SBP of mice was increased in AngII (141 ± 11 mm Hg) vs sham-treated mice (108 ± 2 mm Hg). ScRNA-seq yielded 5,030 cells with 137,990 reads/cell and identified 11 T cell clusters. GO term enrichment analysis revealed that CD8+ natural killer T (NKT), NKT1, γΔ T and T regulatory cell clusters have differentially expressed genes associated with immune cell activation and stress response. Subclustering of T cells expressing the T cell receptor (TCR) Δ constant chain (Trdc) revealed 3 ΔNKT (ΔNKT0, ΔNKT1 and activated ΔNKT cells) and 3 γΔ T cell subpopulations (Trgc1low effector memory, TCR Δ variable 4+ and apoptotic γΔ T cells). AngII increased > 2-fold the frequency of activated ΔNKT cells, and decreased by 74% ΔNKT0 cells. Gene expression profiling revealed that activated ΔNKT and ΔNKT0 cells could be identified using unique markers among Trdc+ cell population, Cd28 and Sell, respectively. Flow cytometry showed that TCRΔ+CD28+Sell- T cells were 1.7-fold increased and TCRΔ+CD28-Sell+ T cells decreased by 52% in MV-PVAT of AngII vs sham-treated mice. Conclusion: This study identified an activated ΔNKT cell subpopulation in MV-PVAT that may play a role in AngII-induced hypertension, vascular injury and T cell activation.