Department of Medicine, Pole of Pharmacology and Therapeutics (FATH), Institut de Recherche Expérimentale et Clinique (IREC), Cliniques Universitaires Saint-Luc, Université catholique de Louvain, 52 avenue Mounier, 1200 Brussels, Belgium.
Division of Cardiology, Pole of Cardiovascular Research, Institut de Recherche Expérimentale et Clinique (IREC), Cliniques Universitaires Saint-Luc, Université catholique de Louvain, 10 Avenue Hippocrate, 1200 Brussels, Belgium.
Eur Heart J. 2018 Mar 7;39(10):888-898. doi: 10.1093/eurheartj/ehx366.
Human and mouse cardiac beta3-adrenergic receptors (beta3AR) exert antipathetic effects to those of beta1-2AR stimulation. We examined their role in modulating myocardial remodelling, particularly fibrosis in response to haemodynamic stress.
Mice with cardiac myocyte-specific expression of beta3AR (ADRB3-tg) or tamoxifen-inducible homozygous deletion (c-Adrb3-ko, with loxP-targeted Adrb3) were submitted to transaortic constriction. A superfusion assay was used for proteomic analysis of paracrine mediators between beta3AR-expressing cardiac myocytes and cardiac fibroblasts cultured separately. We show that cardiac beta3AR attenuate myocardial fibrosis in response to haemodynamic stress. Interstitial fibrosis and collagen content were reduced in ADRB3-tg, but augmented in c-Adrb3-ko. ADRB3 and collagen (COL1A1) expression were also inversely related in ventricular biopsies of patients with valve disease. Incubation of cardiac fibroblasts with media conditioned by hypertrophic myocytes induced fibroblast proliferation, myo-differentiation, and collagen production. These effects were abrogated upon ADRB3 expression in myocytes. Comparative shotgun proteomic analysis of the myocyte secretomes revealed a number of factors differentially regulated by beta3AR, among which connective tissue growth factor [CTGF (CCN2)] was prominently reduced. CTGF was similarly reduced in stressed hearts from ADRB3-tg, but increased in hearts from c-Adrb3-ko mice. CTGF expression was mediated by reactive oxygen species production which was reduced by ADRB3 expression in vitro and in vivo. This antioxidant and anti-fibrotic effect involved beta3AR coupling to the neuronal isoform of nitric oxide synthase (nNOS) in cardiac myocytes, as both were abrogated upon nNOS inhibition or Nos1 homozygous deletion.
Cardiac beta3AR protect from fibrosis in response to haemodynamic stress by modulating nitric oxide and oxidant stress-dependent paracrine signaling to fibroblasts. Specific agonism at beta3AR may offer a new therapeutic modality to prevent cardiac fibrosis.
人类和小鼠的心脏β3-肾上腺素能受体（β3AR）对β1-2AR 刺激的作用产生拮抗作用。我们研究了它们在调节心肌重塑，特别是对血流动力学应激的纤维化中的作用。
心脏肌细胞特异性表达β3AR（ADRB3-tg）或他莫昔芬诱导的纯合缺失（c-Adrb3-ko，带有 loxP 靶向 Adrb3）的小鼠接受主动脉缩窄。使用超速离心测定法对分别培养的β3AR 表达的心肌细胞和心脏成纤维细胞之间的旁分泌介质进行蛋白质组学分析。我们表明，心脏β3AR 可减轻血流动力学应激引起的心肌纤维化。ADRB3-tg 中的间质纤维化和胶原含量减少，但 c-Adrb3-ko 中增加。在瓣膜病患者的心室活检中，ADRB3 和胶原（COL1A1）的表达也呈负相关。用肥大心肌细胞的条件培养基孵育心脏成纤维细胞，可诱导成纤维细胞增殖、肌分化和胶原产生。这些作用在心肌细胞中表达 ADRB3 时被阻断。心肌细胞分泌的蛋白质组比较分析显示，β3AR 调节了许多因子的表达，其中结缔组织生长因子[CTGF（CCN2）]明显减少。ADRB3-tg 应激心脏中的 CTGF 减少，但 c-Adrb3-ko 心脏中的 CTGF 增加。CTGF 的表达是由活性氧的产生介导的，而在体外和体内，ADRB3 的表达均可减少活性氧的产生。这种抗氧化和抗纤维化作用涉及心脏肌细胞中β3AR 与神经元型一氧化氮合酶（nNOS）的偶联，因为这两种作用在 nNOS 抑制或 Nos1 纯合缺失时均被阻断。
心脏β3AR 通过调节向成纤维细胞的一氧化氮和氧化应激依赖性旁分泌信号，防止血流动力学应激引起的纤维化。β3AR 的特异性激动剂可能为预防心脏纤维化提供一种新的治疗方法。
