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.

项目摘要 子宫血管适应在妊娠期间子宫血流的惊人增加至关重要 胎儿发育以及母亲的心血管福祉。虽然血管扩张是 在适应子宫循环至妊娠的重要性，潜在的机制不是 完全理解。在物理膜电位处的自发瞬态向外电流（Stocs）（ 血管平滑肌细胞的30​​-40 mV）从根本上调节血管肌张力和血液流动 在器官和动脉压中。我们在绵羊的初步研究表明怀孕 子宫动脉平滑肌细胞中的StoC显着增加，确定了令人兴奋的调节靶 在妊娠的子宫血管适应中。 STOC主要由大传导CA2+ - 介导 激活的K（BKCA）通道。血管平滑肌中的BKCA通道包含形成通道的 + 亚基和多达四个辅助β1亚基通过ryanodine的开口感知Ca2+火花 接收者。我们以前的研究表明，BKβ1亚基表达的显着上调， 导致β1的增加：孕妇的子宫动脉中的亚基化学计量法。这是由 子宫动脉中BKβ1亚基基因的启动子甲基化降低。动态调节 DNA甲基化和脱甲基化是基因表达表观遗传修饰的主要机制 模式和生物功能。最近的研究表明了十个时期的强大机制 通过将5-甲基胞嘧啶（5MC）转化为活性DNA脱甲基化的易位1-3（TET1-3）蛋白 5-羟基甲基胞嘧啶（5HMC）。我们的初步研究表明怀孕和类固醇恐怖 在子宫中BKβ1启动子上的TET1和TET2表达和5HMC抽象显着增加 动脉，表明在子宫中马酮介导的活性DNA脱甲基的高度新颖机制 血管适应怀孕。此外，初步数据表明妊娠导致 子宫动脉中ryanodine接收器介导的Ca2+火花显着增加。这些令人兴奋的 调查结果和许多新颖的潜在客户，我们现在可以在A中显着向前移动该领域 通过启动新的研究重点来理解分子和表观遗传学的方式。 在子宫动脉血管扩张中，调节StoC的机制是至关重要的 在妊娠期间。这是拟议的研究将检验妊娠上调BKβ1的假设 通过TET介导的DNA脱甲基化的亚基表达，并增加ryanodine受体诱导的Ca2+ 火花，导致子宫血管适应怀孕的stocs升高。结果 拟议的研究将提供对子宫剖学适应分子机制的新见解。 怀孕，将对我们对病理生理机制的理解产生重大影响 怀孕并发症，包括先兆子痫和胎儿生长限制，由 子宫剖道循环。鉴于Stocs在调节血管张力和 几乎所有血管床的压力，揭示了Stocs功能的表观遗传调节血管光滑 肌肉确实会对分子的全面理解产生更大的影响 血管生理和病理生理学的机制。