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

基本信息

批准号：
10224183
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
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-09-19 至 2023-07-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10224183
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 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

项目摘要

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.

项目概要膀胱在充盈过程中必须避免过早收缩，这研究了内在的原因。小鼠和人类逼尿肌的机制，通过伸长来感知体积变化其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，逼尿肌平滑肌细胞（SMC）的伸展会激活外向电流，稳定这些细胞的兴奋性拉伸激活的 K+ 通道的阻断剂会导致显着的激活。充盈过程中膀胱壁短暂收缩（TC）的影响，TC 是感觉的主要刺激物我们发现 Kcnk2 编码主导的拉伸依赖性。逼尿肌 SMC 中的电导 TREK1 在卵巢切除术后雌性激素丧失后下调。我们注意到，当 TREK1 水平降低时，TC 会随之增加，我们还发现雌激素可以。卵巢切除术后膀胱功能已基本恢复正常，这样的发现并不完全符合。关于激素替代疗法对膀胱过度活动症影响的文献，我们将探讨造成这种差异的一个可能原因是雌激素替代的时机。因此，我们提出了实验来研究之间的延迟的影响。卵巢切除术和雌激素替代对雌激素恢复 Kcnk2 和 TREK1 表达的能力的影响我们在初步实验中还发现，正常膀胱对充盈的反应有一个时间- 卵巢切除术后雌激素受体α（ERα）的依赖性丧失因此，我们将研究时间依赖性。雌激素受体的丧失以及受体丧失与有效性降低之间的相关性另一个需要研究的想法是 ERα 和 ERβ 之间的平衡可能会改变。卵巢切除术后，不仅导致雌激素替代的有效性丧失，而且还改变了反应雌激素从有帮助到危险到正常膀胱功能将通过动物来探讨。 SMC 特异性敲除 ERα 和 ERβ 该项目将使用几种最先进的分子和技术。生理测定以提供 TREK1 和可能的 TREK2 表达之间的严格关联 ERα 和 ERβ 表达以及雌激素变化的后果。 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的电导并提出了膀胱过度活动症发生后的机制绝经。