Uterine Arterial Spontaneous Transient Outward Currents in Pregnancy

妊娠期子宫动脉自发瞬时外向电流

• 批准号: 9360213
• 负责人: Lubo Zhang
• 金额: $ 39.5万
• 依托单位: LOMA LINDA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-06-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9360213
• 关键词: Animals; Arteries; Biological Process; Blood Circulation; Blood Vessels; Blood flow; Cardiovascular system; Clinical; Clinical Management; DNA; DNA Methylation Regulation; Data; Down-Regulation; Employee Strikes; Epigenetic Process; Fetal Development; Fetal Growth Retardation; Fetus; Functional disorder; Gene Expression; Gene Expression Profile; Gene-Modified; Genes; Growth; Hormones; Incidence; Maternal Health; Mediating; Membrane Potentials; Methylation; Molecular; Mothers; Muscle Cells; Organ; Outcome; Physiological; Physiology; Positioning Attribute; Pre-Eclampsia; Pregnancy; Pregnancy Complications; Proteins; Regulation; Research; Role; Ryanodine Receptor Calcium Release Channel; Ryanodine Receptors; Series; Sheep; Smooth Muscle Myocytes; Testing; Tetanus Helper Peptide; Up-Regulation; Uteroplacental Circulation; Vascular Smooth Muscle; Vasodilation; demethylation; density; epigenetic regulation; experimental study; fetal; improved; innovation; insight; knock-down; neonatal outcome; novel; perinatal morbidity; pregnant; pressure; promoter; receptor expression; steroid hormone; stoichiometry; vascular bed; virtual

PROJECT SUMMARY Uterine vascular adaptation with the striking increase of uterine blood flow during gestation is essential for fetal development as well as for cardiovascular well-being of the mother. Although vasodilatation is of critical importance in the adaptation of uterine circulation to pregnancy, the underlying mechanisms are not fully understood. Spontaneous transient outward currents (STOCs) at physiological membrane potentials ( 30-40 mV) of vascular smooth muscle cells fundamentally regulate vascular myogenic tone and blood flow in an organ, as well as arterial pressure. Our preliminary studies in sheep revealed that pregnancy significantly increased STOCs in uterine arterial smooth muscle cells, identifing an exciting regulatory target in uterine vascular adaptation in gestation. STOCs are mainly mediated by large-conductance Ca2+- activated K (BKca) channels. The BKca channel in vascular smooth muscle contains the channel-forming  + subunit and up to four accessory β1 subunits that sense Ca2+ sparks via the opening of ryanodine receptors. Our previous studies demonstrated a significant upregulation of BKβ1 subunit expression, resulting in increased β1: subunit stoichiometry in uterine arteries of pregnant animals. This resulted from a decrease in promoter methylation of the BKβ1 subunit gene in uterine arteries. Dynamic regulation of DNA methylation and demethylation is a chief mechanism in epigenetic modifications of gene expression pattern and biological function. Recent studies have suggested a robust mechanism of ten-eleven translocation 1-3 (TET1-3) proteins in active DNA demethylation by converting 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC). Our preliminary studies showed that pregnancy and steroid hormones significantly increased TET1 and TET2 expression and 5hmC abundance at the BKβ1 promoter in uterine arteries, suggesting a highly novel mechanism of hormone-mediated active DNA demethylation in uterine vascular adaptation to pregnancy. In addition, the preliminary data suggested that pregnancy resulted in a significant increase in Ca2+ sparks mediated by ryanodine receptors in uterine arteries. With these exciting findings and many highly novel leads, we are now positioned to move the field forward significantly in a manner by launching a new focus of research aiming at the understanding of molecular and epigenetic mechanisms in the regulation of STOCs that are of fundamental importance in uterine arterial vasodilatation during gestation. Thus, the proposed study will test the hypothesis that pregnancy upregulates BKβ1 subunit expression via TET-mediated DNA demethylation and increases ryanodine receptor-induced Ca2+ sparks, resulting in heightened STOCs in uterine vascular adaptation to pregnancy. The outcome of proposed study will provide novel insights in molecular mechanisms of uteroplacental adaptation to pregnancy, and will have a major impact in our understanding of pathophysiologic mechanisms underlying pregnancy complications including preeclampsia and fetal growth restriction, caused by maladaptation of uteroplacental circulation. Given that STOCs are fundamentally important in regulating vascular tone and pressure in virtually all vascular beds, revealing epigenetic regulation of STOCs function in vascular smooth muscle will indeed have a much broader impact in the comprehensive understanding of molecular mechanisms in vascular physiology and pathophysiology.

项目概要 妊娠期间子宫血流量显着增加，子宫血管适应对于妊娠至关重要。 尽管血管舒张对胎儿发育以及母亲的心血管健康至关重要。 对于子宫循环适应妊娠至关重要，其根本机制并不明确 生理膜电位下的自发瞬态外向电流（STOC）（-） 30-40 mV) 血管平滑肌细胞从根本上调节血管肌源性张力和血流 我们对绵羊的初步研究表明怀孕。 显着增加子宫动脉平滑肌细胞中的 STOC，确定了一个令人兴奋的调节目标 妊娠期子宫血管适应主要由大电导Ca2+-介导。 激活的 K (BKca) 通道 血管平滑肌中的 BKca 通道包含通道形成 。 + 亚基和最多四个辅助 β1 亚基，通​​过兰尼丁的开口感应 Ca2+ 火花 我们之前的研究表明 BKβ1 亚基表达显着上调， 导致怀孕动物子宫动脉中的 β1:α 亚基化学计量增加。 子宫动脉中 BKβ1 亚基基因启动子甲基化的减少。 DNA甲基化和去甲基化是基因表达表观遗传修饰的主要机制 最近的研究表明 10-11 具有强大的机制。 通过将 5-甲基胞嘧啶 (5mC) 转化为活性 DNA 去甲基化中的易位 1-3 (TET1-3) 蛋白 我们的初步研究表明，5-羟甲基胞嘧啶（5hmC）与妊娠和类固醇激素有关。 显着增加子宫中 BKβ1 启动子处的 TET1 和 TET2 表达以及 5hmC 丰度 动脉，提示子宫内激素介导的活性 DNA 去甲基化的一种高度新颖的机制 此外，初步数据表明，怀孕会导致血管适应。 子宫动脉中兰尼碱受体介导的 Ca2+ 火花显着增加。 发现和许多高度新颖的线索，我们现在已经准备好以一种方式显着推动该领域向前发展 方式，启动旨在理解分子和表观遗传学的新研究重点 STOC 的调节机制对于子宫动脉血管舒张至关重要 因此，拟议的研究将检验妊娠上调 BKβ1 的假设。 通过 TET 介导的 DNA 去甲基化实现亚基表达并增加兰尼定受体诱导的 Ca2+ 火花，导致脂肪STOCs在子宫血管适应妊娠的结果。 拟议的研究将为子宫胎盘适应的分子机制提供新的见解 怀孕，并将对我们理解潜在的病理生理机制产生重大影响 妊娠并发症，包括先兆子痫和胎儿生长受限，这是由适应不良引起的 鉴于 STOC 对于调节血管张力和子宫胎盘循环至关重要。 几乎所有血管床的压力，揭示了 STOC 在血管平滑肌中功能的表观遗传调节 肌肉确实会对分子的全面理解产生更广泛的影响 血管生理学和病理生理学的机制。