Downregulation of the β1 adrenergic receptor in the myocardium results in insensitivity to metoprolol and reduces blood pressure in spontaneously hypertensive rats

Abstract

The β1-adrenergic receptor (AR) is the primary β-AR subtype in the heart and is the target of metoprolol (Met), which is commonly used to treat angina and hypertension. Previous studies have revealed a positive correlation between the methylation levels of the adrenoreceptor β1 gene (Adrb1) promoter in the myocardium with the antihypertensive activity of Met in spontaneously hypertensive rats (SHR), which affects β1-AR expression in H9C2 cells. The aim of the present study was to investigate the effects of myocardial β1-AR downregulation using short-hairpin RNA (shRNA) against Adrb1 on the antihypertensive activity of Met in SHR. Recombinant adeno-associated virus type 9 (rAAV9) vectors carrying Adrb1 shRNA (rAAV9-Adrb1) or a negative control sequence (rAAV9-NC) were generated and used to infect rat hearts via the pericardial cavity. The results of reverse transcription-quantitative polymerase chain reaction, immunohistochemistry and western blotting analyses demonstrated that cardiac β1-AR expression in the rAAV9-Adrb1 group was significantly downregulated when compared with the rAAV9-NC group (P<0.001, P<0.001 and P=0.032, respectively). In addition, a greater reduction in systolic blood pressure (SBP) was observed in the rAAV9-NC group compared with the rAAV9-Adrb1 group following Met treatment (P=0.035). Furthermore, downregulation of myocardial β1-AR was associated with a significant decrease in SBP (P<0.001). In conclusion, these data suggest that suppression of β1-AR expression in the myocardium reduces SBP and sensitivity to Met in SHR.

Noradrenaline Modulates the Membrane Potential and Holding Current of Medial Prefrontal Cortex Pyramidal Neurons via β1-Adrenergic Receptors and HCN Channels

“…Unbound antibodies were washed out with PBS, and the Cy3-conjugated goat anti-rabbit (1:200, Jackson ImmunoResearch, catalog number: 111-165-144) secondary antibody was applied at room temperature for 2 h. Next, the sections were washed with PBS (four times for 5 min each), mounted in medium (Vectashield with DAPI, Vector Laboratories, catalog number H-1200) and coverslipped. The specificity of the applied primary antibodies (Abcam, catalog number: ab3442) was recently documented ( Lv et al, 2016 ; Tyurin-Kuzmin et al, 2016 ; Huang et al, 2017 ; Kim et al, 2017 ; Mesquita et al, 2017 ). Immunofluorescence measurements were performed with a confocal laser scanning microscope (FV1000, Olympus, objectives 10× and 60×, image 1024 pixels × 1024 pixels).…”

CRISPR/Cas9 Mediated Deletion of the Angiotensinogen Gene Reduces Hypertension: A Potential for Cure?

“…7 Viral-based methods led to prolonged siRNA expression and more sustained blood pressure reduction. To date, injection of AAVs carrying siRNAs that target AGT, 8,9 β1 adrenergic receptor, 10 Ang II (angiotensin II) type-1 receptor, 11 endothelin-1, 12 and several others [13][14][15][16][17][18] have all been demonstrated to significantly reduce blood pressure; however, the need for AAV persistence to maintain siRNA expression is problematic as the AAV can be lost during cell proliferation. 19 Moreover, despite longer term blood pressure reduction, siR-NAs would still be considered a treatment, not a cure.…”

Response of non-failing hypertrophic rat hearts to prostaglandin F2α

“…1 B). Desensitisation to β-AR stimulation has previously been reported in humans and other rat models of hypertrophy and heart failure ( Huang et al., 2017 ; Wallukat, 2002 ).…”