State Key Laboratory of Membrane Biology, Institute of Molecular Medicine, College of Future Technology, Peking University, Beijing, China (Y.S., D.S., X.H., Y.Z., A.Y.-H.W., R.-P.X.).
Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China (C.X., J.L.).
Circ Res. 2021 Jan 22;128(2):262-277. doi: 10.1161/CIRCRESAHA.120.317011. Epub 2020 Nov 19.
The β-adrenoceptor (β-AR), a prototypical GPCR (G protein-coupled receptor), couples to both G and G proteins. Stimulation of the β-AR is beneficial to humans and animals with heart failure presumably because it activates the downstream G-PI3K-Akt cell survival pathway. Cardiac β-AR signaling can be regulated by crosstalk or heterodimerization with other GPCRs, but the physiological and pathophysiological significance of this type of regulation has not been sufficiently demonstrated.
Here, we aim to investigate the potential cardioprotective effect of β-adrenergic stimulation with a subtype-selective agonist, (R,R')-4-methoxy-1-naphthylfenoterol (MNF), and to decipher the underlying mechanism with a particular emphasis on the role of heterodimerization of β-ARs with another GPCR, 5-hydroxytryptamine receptors 2B (5-HTRs).
Using pharmacological, genetic and biophysical protein-protein interaction approaches, we studied the cardioprotective effect of the β-agonist, MNF, and explored the underlying mechanism in both in vivo in mice and cultured rodent cardiomyocytes insulted with doxorubicin, hydrogen peroxide (HO) or ischemia/reperfusion. In doxorubicin (Dox)-treated mice, MNF reduced mortality and body weight loss, while improving cardiac function and cardiomyocyte viability. MNF also alleviated myocardial ischemia/reperfusion injury. In cultured rodent cardiomyocytes, MNF inhibited DNA damage and cell death caused by Dox, HO or hypoxia/reoxygenation. Mechanistically, we found that MNF or another β-agonist zinterol markedly promoted heterodimerization of β-ARs with 5-HTRs. Upregulation of the heterodimerized 5-HTRs and β-ARs enhanced β-AR-stimulated G-Akt signaling and cardioprotection while knockdown or pharmacological inhibition of the 5-HTR attenuated β-AR-stimulated G signaling and cardioprotection.
These data demonstrate that the β-AR-stimulated cardioprotective G signaling depends on the heterodimerization of β-ARs and 5-HTRs.
β-肾上腺素受体（β-AR）是一种典型的 G 蛋白偶联受体（GPCR），可与 G 蛋白和 G 蛋白偶联。β-AR 的刺激对心力衰竭的人类和动物有益，可能是因为它激活了下游的 G-PI3K-Akt 细胞存活途径。心脏β-AR 信号可以通过与其他 GPCR 的串扰或异二聚化来调节，但这种调节的生理和病理生理意义尚未得到充分证明。
本研究旨在通过使用β-肾上腺素能激动剂（R,R'）-4-甲氧基-1-萘基非诺特罗（MNF），研究β-肾上腺素能刺激的潜在心脏保护作用，并特别强调β-AR 与另一种 GPCR 5-羟色胺受体 2B（5-HTRs）异二聚化的作用，来阐明潜在的机制。
使用药理学、遗传学和生物物理蛋白质-蛋白质相互作用方法，我们研究了β-激动剂 MNF 的心脏保护作用，并在阿霉素、过氧化氢（HO）或缺血/再灌注损伤的体内和培养的啮齿动物心肌细胞中探索了潜在的机制。在阿霉素（Dox）处理的小鼠中，MNF 降低了死亡率和体重减轻，同时改善了心脏功能和心肌细胞活力。MNF 还减轻了心肌缺血/再灌注损伤。在培养的啮齿动物心肌细胞中，MNF 抑制了 Dox、HO 或缺氧/复氧引起的 DNA 损伤和细胞死亡。在机制上，我们发现 MNF 或另一种β-激动剂 zinterol 显著促进了β-AR 与 5-HTRs 的异二聚化。上调异二聚化的 5-HTRs 和β-ARs 增强了β-AR 刺激的 G-Akt 信号和心脏保护作用，而 5-HTR 的敲低或药理学抑制减弱了β-AR 刺激的 G 信号和心脏保护作用。
这些数据表明，β-AR 刺激的心脏保护 G 信号取决于β-ARs 和 5-HTRs 的异二聚化。
