Novel mechanism on subpopulation-dependent biased GPCR signaling in neurons

总结 肾上腺素能受体（AR）是与神经元病症、代谢性疾病和神经元疾病相关的原型GPCR家族。 综合征和心血管疾病。在CNS中，去甲肾上腺素（NE）调节注意力和警觉性。 β 2 AR作为突触后NE效应子在突触能突触中起作用， 与AMPAR、NMDAR和L型Ca 2+通道Cav1.2一起调节神经元兴奋性、突触可塑性， 记忆和学习。它与临床相关，以了解NE相关的精神疾病，如 抑郁症、注意力缺陷多动障碍（ADHD）、焦虑症（例如，创伤后应激 创伤后应激障碍）和阿尔茨海默病。虽然β受体阻滞剂用于治疗各种外周 包括心力衰竭、高血压、青光眼、哮喘和COPD的疾病，其临床用途是 受到包括焦虑和抑郁在内的副作用的阻碍。近年来晶体学研究的爆炸性发展 尽管配体-GPCR相互作用的研究进展缓慢，但对特异性配体如何导致多效性的GPCR相互作用的理解仍然有限。 GPCR的细胞反应（包括副作用）。在这项研究中，我们假设一个独特的 PKA磷酸化β 2ARs亚群控制海马神经元LTCC激活， 被一组偏置配体选择性地激活。我们将通过以下具体目标来检验我们的假设： 目的1是检验β 2 AR在单个细胞中存在于不同功能亚群的假设， 哺乳动物细胞我们将使用生化分离/分级和超分辨率成像， PKA-p β 2AR和GRK-p β 2AR的亚细胞分布特征不同。目的二是检验假设 PKA-p β 2AR通过选择性地调节细胞膜上的离子通道活性， 质膜（PM）。目的3是检验拟交感神经β受体阻滞剂作为偏倚性β受体阻滞剂的假设。 选择性激活β 2AR的PKA磷酸化亚群以激活β 2AR的离子通道的配体。 下午.如果成功的话，这些目标将揭示一个平台，以了解由两个 不同的β 2 AR亚群，并为设计更有效的β-AR药物提供了新的途径， 临床应用副作用少。

Summary Adrenergic receptors (ARs) are a family of prototypical GPCRs linked to neuronal disorders, metabolic syndrome, and cardiovascular diseases. In the CNS, norepinephrine (NE) regulates attention and alertness. The β2AR is emerging as the prevalent postsynaptic NE effector at glutmatergic synapses, where it interacts with AMPAR, NMDAR and L-type Ca2+ channel Cav1.2 to modulate neuronal excitability, synaptic plasticity, and memory and learning. It is clinically relevant to understand NE-linked mental diseases such as depression, attention deficit hyperactivity disorder (ADHD), anxiety disorders (e.g., posttraumatic stress disorder, PTSD) and Alzheimer's disease. While β-blockers are used to treat a variety of peripheral diseases including heart failure, hypertension, glaucoma, asthma, and COPD, their clinical utility is hampered by the side effects including anxiety and depression. Recent explosion of crystallography study of ligand-GPCR interactions, there is still limited understanding on how a specific ligand leads to pleotropic cellular responses (including sides effects) of a GPCR. In this study, we hypothesize that a distinct subpopulation of PKA-phosphorylated β2ARs control LTCC activation in hippocampal neurons, which can be selectively activated by a set of biased ligands. We will test our hypothesis with following specific aims: Aim 1 is to test the hypothesis that β2AR can exist in distinct functional subpopulations in a single mammalian cell. We will use biochemical isolation/fractionation and super-resolution imaging to characterize distinct subcellular distribution of PKA-pβ2AR and GRK-pβ2AR. Aim 2 is to test the hypothesis that PKA-pβ2AR transduce biased signal through selectively modulation of ion channel activity at the plasma membrane (PM). Aim 3 is to test the hypothesis that sympathomimetic β-blockers act as biased ligands that selectively activate PKA-phosphorylated subpopulation of β2AR to activate ion channel at the PM. If successful, these aims will reveal a platform to understand the biased signaling induced by two distinct subpopulations of β2AR, and offering a new avenues for designing more efficacious β-AR drugs with fewer side effects in clinical applications.