Regulation of mechanosensitive K+ channels in detrusor smooth muscle by estrogen

雌激素对逼尿肌平滑肌机械敏感 K 通道的调节

• 批准号: 10457352
• 负责人: KENTON M SANDERS
• 金额: $ 42.1万
• 依托单位: UNIVERSITY OF NEVADA RENO
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-09-19 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10457352
• 关键词: Acute; Adverse effects; Affect; Animal Model; Animals; Biological Assay; Bladder; Bladder Control; Body part; Cells; Chronic; Conflict (Psychology); Data; Dependence; Development; Down-Regulation; Effectiveness; Enhancers; Equilibrium; Estradiol; Estrogen Receptor alpha; Estrogen Receptor beta; Estrogen Receptors; Estrogen Replacements; Estrogen Therapy; Estrogens; Excision; Female; Gene Expression; Generations; Genes; Hormone replacement therapy; Hormones; Human; Impairment; In Vitro; Ion Channel; Knock-out; Knowledge; Lead; Literature; Mediating; Membrane; Menopause; Molecular; Mus; Muscle Fibers; Organ; Outcome; Ovariectomy; Ovary; Overactive Bladder; Patients; Pattern; Pelvis; Physiological; Plasma; Postmenopause; Potassium Channel; Preclinical Testing; Production; Regulation; Reporting; Role; Sensory; Smooth Muscle; Smooth Muscle Myocytes; Stimulant; Stretching; Symptoms; Testing; Time; Transcript; Treatment Effectiveness; Treatment Efficacy; Woman; detrusor muscle; effectiveness evaluation; experimental study; female sex hormone; in vivo; insight; knock-down; novel; premature; pressure; protein expression; receptor; response; success

Project Summary The bladder must refrain from premature contraction during filling. This project investigates an intrinsic mechanism of detrusor muscles in mouse and humans that senses volume changes through the elongation of smooth muscle fibers. The mechanism is due to the expression and function of stretch-dependent K+ channels. Previous studies have shown that stretch of detrusor smooth muscle cells (SMCs) activates outward current that stabilizes the excitability of these cells. Blockers of the stretch-activated K+ channels cause significant activation of transient contractions (TCs) in the bladder wall during filling, and TCs are a primary stimulant of sensory information conveyed by pelvic afferents. We found that Kcnk2, which encodes the dominant stretch-dependent conductance TREK1 in detrusor SMCs, is down-regulated after loss of female hormones following ovariectomy. We noted a concomitant increase in TCs when TREK1 levels decreased. We also found that estrogen can rescue nearly normal bladder function after ovariectomy. Such findings do not completely agree with the literature regarding the effects of hormone replacement therapy on overactive bladder, and we will explore possible reasons for this discrepancy. One explanation could be that the timing of estrogen replacement could be critical for efficacy. Thus, we have proposed experiments to study the effects of the delay between ovariectomy and estrogen replacement on the ability of estrogen to restore Kcnk2 and TREK1 expression and normal bladder responses to filling. We have also found in preliminary experiments that there is a time- dependent loss of estrogen receptor α (ERα) after ovariectomy. Thus, we will investigate the time-dependence of the loss of estrogen receptors and the correlation between receptor loss and reduction in the effectiveness of estrogen replacement. Another idea to be investigated is that the balance between ERα and ERβ might change after ovariectomy, causing not only loss of effectiveness of estrogen replacement but also shifting the responses to estrogen from helpful to eleterious to normal bladder function. This question will be explored using animals with SMC-specific knockouts of ERα and ERβ. The project will use several state-of-the-art molecular and physiological assays to provide rigorous associations between expression of TREK1 and possibly TREK2 channels and bladder function. The consequences of changes in ERα and ERβ expression and estrogen regulation of Kcnk2 and Kcnk10 will provide new information about the role of stretch-dependent K+ conductances in bladder function and suggest a mechanism for the development of overactive bladder after menopause.

项目摘要 膀胱在填充过程中必须避免过早收缩。该项目调查了一个内在的 小鼠和人类中的迫切肌肉的机制，这些机制通过伸长来感知体积的变化 平滑肌纤维。该机制是由于拉伸依赖性K+通道的表达和功能。 先前的研究表明，弯曲器平滑肌细胞（SMC）激活向外电流 稳定这些细胞的兴奋。拉伸激活的K+通道的阻滞剂引起显着激活 填充过程中膀胱壁中的瞬态收缩（TC），TCS是感觉的主要刺激物 骨盆传入传达的信息。我们发现编码主要的拉伸依赖性的KCNK2 卵巢切除术后女性恐怖片丧失后，逼尿肌SMC中的电导Trek1被下调。 我们注意到，当Trek1水平降低时，TCS伴随着增加。我们还发现雌激素可以 卵巢切除术后营救几乎正常的膀胱功能。这样的发现并不完全同意 关于马内替代疗法对过度活动膀胱的影响的文献，我们将探索 这种差异的可能原因。一种解释可能是，雌激素替代的时机可以 对有效性至关重要。这是我们提出的实验来研究 关于雌激素恢复KCNK2和Trek1表达的能力以及 正常的膀胱响应对填充。我们还在初步实验中发现，有时间 卵巢切除术后雌激素受体α（ERα）的依赖丧失。那我们将研究时间依赖性 雌激素受体丧失以及受体丧失与降低的相关性 雌激素替代。要研究的另一个想法是，ERα和ERβ之间的平衡可能会改变 卵巢切除术后，不仅会导致雌激素替代的有效性丧失，还会改变反应 雌激素从有益到优雅到正常的膀胱功能。这个问题将使用动物探讨 与ERα和ERβ的SMC特异性敲除。该项目将使用几个最先进的分子和 生理测定，以提供Trek1表达和可能的Trek2之间的严格关联 通道和膀胱功能。 ERα和ERβ表达和雌激素的变化的后果 KCNK2和KCNK10的调节将提供有关拉伸依赖性K+作用的新信息 膀胱功能中的电导，并提出了一种机制，用于开发过度活跃的膀胱之后 绝经。