Uterine bitter taste receptors in pregnancy and preterm labor management

摘要 子宫收缩能力由一个复杂的系统调节和控制，以维持怀孕和 分娩发生在足月。在怀孕37周之前发生的协调子宫收缩，即， 早产(PTL)可能导致早产(PTB)，影响1500万新生儿，造成100万人死亡 全球每年的新生儿死亡人数。鉴于宫缩是PTL的中心特征，因此使用宫缩 然而，在肺结核的治疗中，目前的治疗方法还不够有效。我们最近发现子宫光滑 小鼠和人的肌肉细胞表达苦味受体(TAS2Rs)及其典型受体 信号组件(即G蛋白Gustducin和PLCβ2)。还有苦味剂(例如，邻菲咯啉(Phen)， 以及FDA批准的抗疟疾药物氯喹)松弛由子宫强直性预收缩的子宫条(例如， 催产素和前列腺素F2α)比目前常用的催产素和前列腺素F2更完整(即硝苯地平， 吲哚美辛和硫酸镁)。此外，苦味剂(如氯喹)可预防小鼠肺结核 细菌内毒素脂多糖和核孕酮受体拮抗剂RU486 而不是通常使用的催产素分解法，并且以一种味精依赖的方式。在我们的初步研究中，我们进一步 研究发现：(1)phen能阻断5-羟色胺、内皮素-1、 神经递质S和U-46619，都是子宫内的病理生理介质。(2)Tas2r在USM中的表达是 在怀孕小鼠接近分娩时下降，并在分娩后恢复；(3)同时 USM中表达的三个主要TAS2R的缺失增加了小鼠患肺结核的可能性。因此，我们 提出(1)TAS2Rs是一类调节子宫收缩和妊娠持续时间的蛋白质；(2) TAS2R激动剂是一种广谱的代谢产物，可能适用于肺结核的治疗。为了测试这些 假设，我们将直接研究苦味如何激活TAS2R信号通路来放松人类 用药理学方法和siRNA慢病毒表达技术研究子宫肌层(目标1)。到时候我们会的 使用Tas2r缺失小鼠来确定苦味是否激活TAS2Rs导致USM松弛，以及 TAS2Rs在妊娠期间是否对维持子宫静止至关重要， 持续时间，小鼠(目标2)。最后，我们将研究苦味剂对预防小鼠肺结核的有效性。 并确定TAS2Rs在苦味者预防内毒素或RU486中的作用。 诱发性肺结核(目标3)。这项研究将揭示苦味剂放松小鼠的分子机制。 和人类子宫，确定TAS2R家族是否在怀孕期间子宫静止中起主要作用 和分娩，确定TAS2R家族是否是治疗人类PTL的有吸引力的治疗靶点 怀孕，并有助于确定苦味是否可以发展为新的更有效的宫内分解药 用于肺结核的管理。

Abstract Uterine contractility is regulated and controlled by a complex system such that pregnancy is maintained and parturition occurs at full term. Coordinated uterine contractions occurring prior to 37 weeks gestation, i.e., preterm labor (PTL), could lead to preterm birth (PTB) which affects 15 million newborns and causes 1 million neonatal deaths worldwide annually. Given that contractions are a central feature of PTL, tocolytics are used in PTB management, yet current tocolytics are not sufficiently effective. We recently found that uterine smooth muscle (USM) cells from mouse and human express bitter taste receptors (TAS2Rs) and their canonical signaling components (i.e., G-protein gustducin and PLCβ2). Also bitter tastants (e.g., phenanthroline (PHEN), and chloroquine, a FDA-approved antimalarial drug) relax uterine strips pre-contracted by uterotonics (e.g., oxytocin and prostaglandin F2α) more completely than current commonly used tocolytics (i.e., nifedipine, indomethacin and MgSO4). Moreover, bitter tastants (e.g., chloroquine) can prevent mouse PTB induced by bacterial endotoxin lipopolysaccharide (LPS) and nuclear progesterone receptor antagonist RU486 more often than commonly used tocolytics and in a gustducin dependent manner. In our preliminary studies, we further found that (1) PHEN can stop pregnant mouse uterine contractions induced by serotonin, endothelin-1, neuromedin S and U-46619, all pathophysiological mediators in the uterus, (2) Tas2r expression in USM is decreased when pregnant mice approach parturition and is restored after labor, and (3) the simultaneous deletion of the three main Tas2rs expressed in USM increases the probability of PTB in mice. We therefore propose that (1) TAS2Rs are a class of proteins regulating uterine contraction and gestational duration, and (2) TAS2R agonists are broad spectrum tocolytics potentially suitable for PTB management. To test these hypotheses, we will directly study how bitter tastants activate the TAS2R signaling pathway to relax human myometrium with pharmacological approaches and siRNA lentiviral expression technology (Aim 1). We will then use Tas2r deletion mice to determine whether bitter tastants activate TAS2Rs to cause USM relaxation, and whether the TAS2Rs are critical for maintaining uterine quiescence during pregnancy, setting gestational duration, in mice (Aim 2). Finally, we will study the effectiveness of bitter tastants in preventing mouse PTB induced by LPS and RU486, and determine the role of TAS2Rs in bitter tastants' prevention of LPS- or RU486- induced PTB (Aim 3). This study will uncover the molecular mechanisms by which bitter tastants relax mouse and human uteri, determine whether the TAS2R family plays a major role in uterine quiescence during pregnancy and parturition, establish whether the TAS2R family is an attractive therapeutic target for treating PTL in human pregnancy, and help determine whether bitter tastants can be developed as new and more effective tocolytics for PTB management.