Thotamune Waruna, Ubeysinghe Sithurandi, Shrestha Kendra K, Mostafa Mahmoud Elhusseiny, Young Michael C, Karunarathne Ajith
Department of Chemistry, Saint Louis University, Saint Louis, MO 63103, USA.
Department of Chemistry and Biochemistry, School of Green Chemistry and Engineering, The University of Toledo, Toledo, OH 43606, USA.
bioRxiv. 2024 Feb 15:2024.02.14.580335. doi: 10.1101/2024.02.14.580335.
Beta-adrenergic receptors (βARs) are G protein-coupled receptors (GPCRs) that mediate catecholamine-induced stress responses, such as heart rate increase and bronchodilation. In addition to signals from the cell surface, βARs also broadcast non-canonical signaling activities from the cell interior membranes (endomembranes). Dysregulation of these receptor pathways underlies severe pathological conditions. Excessive βAR stimulation is linked to cardiac hypertrophy, leading to heart failure, while impaired stimulation causes compromised fight or flight stress responses and homeostasis. In addition to plasma membrane βAR, emerging evidence indicates potential pathological implications of deeper endomembrane βARs, such as inducing cardiomyocyte hypertrophy and apoptosis, underlying heart failure. However, the lack of approaches to control their signaling in subcellular compartments exclusively has impeded linking endomembrane βAR signaling with pathology. Informed by the β1AR-catecholamine interactions, we engineered an efficiently photo-labile, protected hydroxy β1AR pro-ligand (OptoIso) to trigger βAR signaling at the cell surface, as well as exclusive endomembrane regions upon blue light stimulation. Not only does OptoIso undergo blue light deprotection in seconds, but it also efficiently enters cells and allows examination of G protein heterotrimer activation exclusively at endomembranes. In addition to its application in the optical interrogation of βARs in unmodified cells, given its ability to control deep organelle βAR signaling, OptoIso will be a valuable experimental tool.
β-肾上腺素能受体（βARs）是G蛋白偶联受体（GPCRs），介导儿茶酚胺诱导的应激反应，如心率加快和支气管扩张。除了来自细胞表面的信号外，βARs还能从细胞内膜（内膜系统）传递非经典信号活动。这些受体途径的失调是严重病理状况的基础。βAR过度刺激与心脏肥大有关，进而导致心力衰竭，而刺激受损则会导致战斗或逃跑应激反应和体内平衡受损。除了质膜βAR外，新出现的证据表明更深层的内膜βAR具有潜在的病理意义，例如诱导心肌细胞肥大和凋亡，这是心力衰竭的潜在原因。然而，由于缺乏专门控制其在亚细胞区室中信号传导途径的方法，阻碍了将内膜βAR信号传导与病理学联系起来。基于β1AR-儿茶酚胺相互作用，我们设计了一种高效的光不稳定、受保护的羟基β1AR前体配体（OptoIso），以在蓝光刺激下在细胞表面以及特定的内膜区域触发βAR信号传导。OptoIso不仅能在几秒钟内通过蓝光脱保护，还能有效进入细胞，并允许仅在内膜处检测G蛋白异三聚体的激活。除了在未修饰细胞中对βAR进行光学检测的应用外，鉴于其能够控制深层细胞器βAR信号传导的能力，OptoIso将是一种有价值的实验工具。
