Muscarinic acetylcholine receptor subtypes: physiological roles

细胞M3毒蕈碱乙酰胆碱（ACh）受体（M3 Rs）的变构调节大大改善了葡萄糖稳态 我们先前证明，胰腺细胞表达的M3 R在刺激胰岛素分泌和维持葡萄糖稳态中起关键作用。出于这个原因，我们研究了M3 R功能的正变构调节剂（PAM）是否可以通过促进胰岛素释放来改善小鼠的葡萄糖稳态。变构毒蕈碱剂的一个优点是它们尊重M3 R活性的ACh依赖性时空控制。我们发现，VU 0119498，一种已知在M3 R处充当PAM的药物，显著增强了ACh诱导的胰岛素从培养细胞以及小鼠和人胰岛的释放。这种反应在缺乏M3 R的胰岛中不存在，表明M3 R的参与。VU 0119498处理野生型小鼠，但不处理缺乏M3 R的突变小鼠，刺激体内胰岛素释放，从而改善葡萄糖耐量。重要的是，糖尿病前期小鼠的VU 0119498治疗引发了胰岛素释放的增强并恢复了正常的葡萄糖耐量。这项概念验证研究强烈表明，M3 R PAM可能成为临床上有用的新型抗糖尿病药物。 (Zhu L，Rossi M，Cohen A，Pham J，Zheng H，Dattaroy D，Mukaibo T，Melvin JE，Langel JL，Hattar S，Matschinsky FM，Appella DH，Doliba NM，Wess J.细胞M3毒蕈碱乙酰胆碱受体的变构调节大大改善了瘦和肥胖小鼠的葡萄糖稳态。Proc Natl Acad Sci USA 116，18684-18690，2019） 以下总结的结果是在合作研究中获得的。 M3 R在心脏传导系统发育中的关键作用 为了确定调节心脏传导系统（CCS）发育的细胞通路，我们在斑马鱼胚胎中进行了化合物筛选。该筛选确定托特罗定，毒蕈碱受体拮抗剂，作为CCS发展的修饰剂。托特罗定治疗引起心率减慢、心包水肿和心律失常。阻断M3 R可诱导基因表达的变化，导致窦房细胞的扩增和房室特性的丧失。来自工程化人心肌模型的转录组数据进一步证实了M3 R在心脏祖细胞特化和分化过程中的作用。这些数据表明，M3 R在发育中的窦房结和房室管之间保持微妙的平衡，从而防止心律失常的发展。 （Burczyk MS，Burkhalter MD，Tena TC，Grisanti LA，Kauk M，Matysik S，Donow C，Kustermann M，Rothe M，Cui Y，Raad F，Laue S，Moretti A，Zimmermann WH，Wess J，Khl M，Hoffmann C，蒂利DG，Philipp M.毒蕈碱受体促进起搏器的命运在斑马鱼的二级传导系统组织的代价。JCI Insight 4（20），pii：121971，2019） 毒蕈碱受体调节早期红系祖细胞的自我更新 早期红系祖细胞，爆发形成单位红系（BFU-E），具有自我更新的能力，因此作为治疗贫血的关键细胞类型。我们证明了M4毒蕈碱受体（M4 Rs）在调节BFU-E自我更新中起作用，并且M4 Rs的药理学阻断可纠正骨髓增生异常综合征（MDS）贫血、衰老和溶血。毒蕈碱受体拮抗剂能够纠正MDS、衰老和体内溶血小鼠模型中的贫血。毒蕈碱受体阻断剂对促进BFU-E扩增的作用是通过增强CREB的活性介导的，CREB靶向BFU-E自我更新的几个关键调节因子。这些数据确定毒蕈碱受体拮抗剂作为与MDS、老化和溶血相关的贫血的潜在疗法。 （Trivedi G，Inoue D，Chen C，Bitner L，Chung YR，Taylor J，Gnen M，Wess J，Abdel-Wahab O，Zhang L.毒蕈碱型乙酰胆碱受体调节早期红系祖细胞的自我更新。Sci Transl Med 11（511），pii：eaaw3781，2019） 评论 Zhu L，Rossi M，Doliba NM，Wess J. β细胞M3毒蕈碱乙酰胆碱受体作为新型抗糖尿病药物的潜在靶点。Int Immunopharmacol 81：106267. doi：10.1016/j.intimp.2020.106267（会议记录），2020年。 Wess J.毒蕈碱受体。在“Encyclopedia of Molecular Pharmacology”，第3版中，eds. S. Offermanns和W.罗森塔尔，施普林格，柏林，2020年。

Allosteric modulation of -cell M3 muscarinic acetylcholine (ACh) receptors (M3Rs) greatly improves glucose homeostasis We previously demonstrated that M3Rs expressed by pancreatic -cells play a key role in stimulating insulin secretion and maintaining glucose homeostasis. For this reason, we examined whether a positive allosteric modulator (PAM) of M3R function can improve glucose homeostasis in mice by promoting insulin release. An advantage of allosteric muscarinic agents is that they respect the ACh-dependent spatio-temporal control of M3R activity. We found that VU0119498, a drug known to act as a PAM at M3Rs, significantly augmented ACh-induced insulin release from cultured -cells and mouse and human pancreatic islets. This response was absent in islets lacking M3Rs, indicative of the involvement of M3Rs. VU0119498 treatment of wild-type mice, but not of mutant mice lacking M3Rs in -cells, stimulated insulin release in vivo, thus improving glucose tolerance. Importantly, VU0119498 treatment of pre-diabetic mice triggered enhanced insulin release and restored normal glucose tolerance. This proof-of-concept study strongly suggests that M3R PAMs may become clinically useful as novel antidiabetic agents. (Zhu L, Rossi M, Cohen A, Pham J, Zheng H, Dattaroy D, Mukaibo T, Melvin JE, Langel JL, Hattar S, Matschinsky FM, Appella DH, Doliba NM, Wess J. Allosteric modulation of -cell M3 muscarinic acetylcholine receptors greatly improves glucose homeostasis in lean and obese mice. Proc Natl Acad Sci USA 116, 18684-18690, 2019) The results summarized below were obtained in collaborative studies. Key role of M3Rs in the development of the cardiac conduction system To identify cellular pathways that regulate the development of the cardiac conduction system (CCS), we performed a compound screen in zebrafish embryos. This screen identified tolterodine, a muscarinic receptor antagonist, as a modifier of CCS development. Tolterodine treatment caused reduced heart rate, pericardial edema, and arrhythmia. Blockade of M3Rs induced changes in gene expression that led to the amplification of sinoatrial cells and loss of atrioventricular identity. Transcriptome data from an engineered human heart muscle model further corroborated a role of M3Rs during cardiac progenitor specification and differentiation. These data indicate that M3Rs maintain a delicate balance between the developing sinoatrial node and the atrioventricular canal, thus preventing the development of arrhythmias. (Burczyk MS, Burkhalter MD, Tena TC, Grisanti LA, Kauk M, Matysik S, Donow C, Kustermann M, Rothe M, Cui Y, Raad F, Laue S, Moretti A, Zimmermann WH, Wess J, Khl M, Hoffmann C, Tilley DG, Philipp M. Muscarinic receptors promote pacemaker fate at the expense of secondary conduction system tissue in zebrafish. JCI Insight 4(20), pii: 121971, 2019) Muscarinic receptors regulate self-renewal of early erythroid progenitors The early erythroid progenitor, burst-forming unit erythroid (BFU-E), has the ability for self-renewal, thus serving as a key cell type for the treatment of anemias. We demonstrated that M4 muscarinic receptors (M4Rs) play a role in regulating BFU-E self-renewal and that pharmacological blockade of M4Rs corrects anemias of myelodysplastic syndrome (MDS), aging, and hemolysis. Muscarinic receptor antagonists were able to correct anemias in mouse models of MDS, aging, and hemolysis in vivo. The effects of muscarinic receptor blockade on promoting expansion of BFU-Es were mediated by enhanced activity of CREB which targets several key regulators of BFU-E self-renewal. These data identify muscarinic receptor antagonists as potential therapies for anemias associated with MDS, aging, and hemolysis. (Trivedi G, Inoue D, Chen C, Bitner L, Chung YR, Taylor J, Gnen M, Wess J, Abdel-Wahab O, Zhang L. Muscarinic acetylcholine receptor regulates self-renewal of early erythroid progenitors. Sci Transl Med 11(511), pii: eaaw3781, 2019) Reviews Zhu L, Rossi M, Doliba NM, Wess J. Beta-cell M3 muscarinic acetylcholine receptors as potential targets for novel antidiabetic drugs. Int Immunopharmacol 81:106267. doi: 10.1016/j.intimp.2020.106267 (Meeting Proceedings), 2020. Wess J. Muscarinic receptors. In "Encyclopedia of Molecular Pharmacology", 3nd ed., eds. S. Offermanns and W. Rosenthal, Springer, Berlin, 2020.