Identification and Regulation of the Myometrial Leak Current

子宫肌层漏电流的识别和调节

• 批准号: 8644504
• 负责人: Erin Reinl
• 金额: $ 2.89万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8644504
• 关键词: Academia; Acetylcholine; Action Potentials; Address; Aftercare; Agonist; Biochemistry; Cations; Cesarean section; Childbirth; Consultations; Data; Development; Dystocia; Electrophysiology (science); Fetus; Frequencies; Functional disorder; Future; GTP-Binding Proteins; Gadolinium; Gap Junctions; Gastrointestinal tract structure; Genes; Heart; Human; In Vitro; Investigation; Ion Channel; Isometric Exercise; Journals; Knowledge; Measures; Methods; Molecular; Molecular Biology; Morbidity - disease rate; Mus; Myometrial; Outcome; Oxytocin; Pacemakers; Pathway interactions; Peer Review; Pharmaceutical Preparations; Pharmacology; Play; Pregnancy; Premature Labor; Property; Proteins; Publications; RNA Interference; Regulation; Reporting; Research; Role; Scientist; Signal Pathway; Smooth Muscle Myocytes; Sodium Channel; Source; Staging; Sum; Technology; Telemetry; Testing; Therapeutic Intervention; Time; Tissues; Training; United States; Uterine Contraction; Uterus; Work; base; career; fetal; gadolinium oxide; in vivo; inhibitor/antagonist; meetings; myometrium; pre-doctoral; public health relevance; response; small hairpin RNA; src-Family Kinases; success; uterine contractility; uterine smooth muscle cell

DESCRIPTION (provided by applicant): The onset and success of labor, at term or preterm, depends on an increase in rhythmic uterine contractions. Contractions can be induced and augmented through oxytocin (OT) treatment, but in recent years, OT has been listed as a High-Alert medication because of its unpredictable outcomes. Therefore, there is a need to better understand its basic mechanisms in regulating uterine contractility. Uterine contractions are regulated by the sum of ion channel activity in myometrial smooth muscle cells (MSMCs). Myometrium possesses an intrinsic ability to produce rhythmic contractions, the pace of which relies on a pacemaker potential. Despite identification of the uterine pacemaker potential in the 1950s, our understanding of the genes and molecular mechanisms that underlie this potential remains limited. In the heart and gastrointestinal tract, pacemaker potentials result from an inward leak of cations through a combination of ion channels. Although a cationic leak current has been measured in the myometrium, the channel that conducts the leak current is unknown. The central hypothesis of this proposal is that a recently described ion channel, the sodium leak channel non-selective (NALCN), in part, underlies the leak current measured in uterine smooth muscle cells, regulates the frequency of uterine contractions, and is modulated by uterotonins including oxytocin and acetylcholine (ACh). This hypothesis is based on preliminary data indicating that NALCN is expressed in the uterus and that knockdown of the gene encoding NALCN reduces the leak current in MSMCs. Additionally, others have shown that NALCN activity can be modulated by agonists, including ACh. This hypothesis will be addressed by pursuing the following aims: 1) determine the extent to which NALCN contributes to the leak current and pacemaker potential in MSMCs and define its regulation throughout pregnancy, 2) determine the effects of uterotonins on leak current activity, and identify the responsible signaling pathway, and 3) elucidate the functional importance of NALCN and the leak current in regulating the pace of spontaneous and agonist-induced uterine contractions. These aims will be addressed by using both mouse and human uterine tissue with a combination of molecular biology, biochemistry, electrophysiology, pharmacology, RNAi technology, isometric tension recordings, and in vivo intrauterine telemetry. The proposed research is significant because the results will add to our currently vague knowledge of the pacemaker potential and may provide targets for future advancements in the treatment of uterine dysfunction. The proposed studies support a predoctoral training plan that also includes coursework, scientific meetings, and consultation with other scientists. This will prepare the applicant for a successful career in academia. Finally, the end results will be submitted for publication in peer-reviewed journals.

描述（申请人提供）：足月或早产分娩的开始和成功取决于子宫节律性收缩的增加。宫缩可以通过催产素（OT）治疗来诱导和增强，但近年来，OT因其不可预测的结果而被列为高警戒药物。因此，有必要更好地了解其调节子宫收缩力的基本机制。子宫收缩受子宫肌层平滑肌细胞（MSMCs）中离子通道活性总和的调节。子宫肌层具有产生节律性收缩的内在能力，其节奏依赖于起搏电位。尽管在20世纪50年代发现了子宫起搏器的潜力，但我们对这种潜力背后的基因和分子机制的理解仍然有限。在心脏和胃肠道中，起搏电位是由阳离子通过离子通道的组合向内泄漏引起的。虽然在子宫肌层中测量到阳离子漏电流，但传导漏电流的通道尚不清楚。该提议的中心假设是最近描述的离子通道，钠漏通道非选择性（NALCN），部分地是在子宫平滑肌细胞中测量的漏电流的基础，调节子宫收缩的频率，并且由包括催产素和乙酰胆碱（ACh）的子宫收缩素调节。该假设基于初步数据，表明NALCN在子宫中表达，并且敲低编码NALCN的基因降低了MSMC中的漏电流。另外，其他人已经表明NALCN活性可以通过激动剂（包括ACh）调节。这一假设将通过追求以下目标来解决：1）确定NALCN对MSMC中的漏电流和起搏电位的贡献程度，并定义其在整个妊娠期间的调节，2）确定子宫激素对漏电流活性的影响，并鉴定负责的信号传导途径，阐明NALCN和漏电流在调节自发性和激动剂诱导的子宫收缩速度中的功能重要性。这些目标将通过使用小鼠和人类子宫组织，结合分子生物学、生物化学、电生理学、药理学、RNAi技术、等长张力记录和体内子宫内遥测来实现。这项拟议的研究意义重大，因为研究结果将增加我们目前对起搏器潜力的模糊认识，并可能为未来子宫功能障碍治疗的进展提供目标。拟议的研究支持博士前培训计划，其中还包括课程，科学会议，并与其他科学家咨询。这将为申请人在学术界取得成功做好准备。最后，最终结果将提交同行评审期刊发表。