Heterogeneity of estrogen and β-adrenergic receptors in female human coronary artery endothelial cells

Introduction Estrogen protects vascular function, likely via adrenergic modulation. Previous studies of estrogen and beta-adrenoceptor (β-AR) interactions relied on non-coronary or animal models, limiting relevance to human coronary endothelium. This study aimed to characterize estrogen receptor (ER) and β-AR expression in human coronary artery endothelial cells (HCAECs), evaluate inter-donor variability, and determine whether ER stimulation alters β-AR gene expression. Methods HCAECs from female donors were analyzed for expression of ERs (ERα, ERβ, GPER), and β-ARs (β 1 -, β 2 -, β 3 -AR) at mRNA and protein levels using RT-qPCR, western blotting, and immunofluorescence, with assessment of inter-donor variability. To investigate estrogen–β-AR interactions, cells were treated with 1 and 10 nM 17β-estradiol or 10 nM selective ER agonists; PPT (Propylpyrazoletriol, ERα), DPN (Diarylpropionitrile, ERβ), G-1 (G protein-coupled estrogen receptor, GPER) for 4, 12, and 24 h, and β-AR mRNA expression was measured. Results Immunofluorescence revealed presence of all three ERs and β-ARs in the HCAECs. ERα had the lowest mRNA expression, while GPER was the most abundant, with donor-dependent variability. ERβ and GPER proteins were slightly higher than ERα. β 3 -AR exhibited the lowest mRNA, β 2 -AR was the highest, and donor-specific differences were observed. Stimulation with 17β-estradiol or selective ER agonists did not alter β-AR mRNA expression. Conclusion These findings demonstrate donor variability in ER and β-AR expression in HCAECs, limiting generalization. Under the tested conditions estrogen and ER agonists did not alter β-AR mRNA levels, suggesting that short-term ER stimulation is unlikely to regulate β-AR expression at the transcriptional level within this experimental setting.