Abstract 101: Similar Cd28 + Delta T Effector Memory Cell Subpopulations Are Present In Murine Perivascular Tissues Of Angiotensin II-infused Male Mice And Subcutaneous White Adipose Tissue Of Obese Women

Abstract

Introduction: The innate-like γδ T cells play a role in angiotensin II (AngII)-induced hypertension, mesenteric artery injury and T cell activation in mesenteric vessels/perivascular adipose tissue (MV/PVAT) in mice. Blood γδ T cells frequency is associated with systolic blood pressure in humans. Obesity was associated with small artery injury in subcutaneous white adipose tissue (WAT) and is a risk factor for hypertension in humans. We hypothesized that single cell RNA sequencing (scRNA-seq) in MV/PVAT of AngII-infused vs control mice and in subcutaneous WAT of obese vs lean humans will reveal γδ T cell subpopulations involved in hypertension, vascular injury and T cell activation. Methods: 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. MV/PVAT were collected, and T cells were isolated and used for scRNA-seq. γδ T cell subpopulations were studied by subclustering T cells expressing the T cell receptor δ constant chain. Cell subpopulations were validated by flow cytometry. Subcutaneous WAT CD45 + cell ScRNA-seq data of 3 lean and 3 obese women were obtained from GEO NCBI database (GSE155960) and γδ T cell subpopulations analyzed as above. Results: ScRNA-seq identified 6 murine and 9 human δ T cell subclusters. AngII increased Cd28 high (% of T cells: 3.6±0.9 vs 1.4±0.2) and Trdv4 + δ T effector memory (EM) cells (7.3±1.3 vs 3.4±1.7) and lowered resting δ T cells (1.0±0.2 vs 4.2±1.5) in mice. Cd28 high δ T EM and resting δ T cell study by flow cytometry using unique marker pairs, CD28 + SELL - and CD28 - SELL + , showed that AngII increased CD28 + SELL - (cell number: 376±48 vs 220±40) and decreased CD28 - SELL + δ T cells (23±4 vs 45±4) in MV/PVAT. Cd28 / CD28 subclustering of δ T cells identified 4 human and murine cell populations and showed that AngII increased Cd28 + γδ natural killer T EM (% of T cells: 1.9±0.3 vs 0.5±0.2) and Cd28 high δ T EM cell subpopulations (1.6±0.5 vs 0.2±0.1) in mice, and that CD28 + δ T EM-1 cell subpopulation tended to be increased in obese vs lean women. Conclusion: ScRNA-seq revealed similar δ T EM cell subpopulations expressing CD28 in murine MV/PVAT and human subcutaneous WAT that could play a role in hypertension, vascular injury and T cell activation.