Role of PKCbeta and oxidant signaling in neonatal pulmonary hypertension

 描述（由申请人提供）：肺动脉高压（PH）是婴儿发病率和死亡率的重要来源。虽然血管收缩被广泛认为是一个关键的 作为新生儿PH的介质，关于这种情况下的血管收缩机制知之甚少，并且目前的血管扩张剂治疗在很大程度上无效。本申请的总体目标是鉴定负责PKC介导的肺血管收缩的血管平滑肌（VSM）信号传导机制，以及该信号传导途径在新生儿中血管收缩剂反应性、动脉重塑和PH的慢性缺氧（CH）依赖性增加中的作用。基于初步研究，我们的中心假设是新生儿CH通过肺VSM中PKCβ诱导的线粒体ROS（mitoROS）信号转导介导自发性肺动脉张力、增强激动剂诱导的肺血管收缩剂敏感性、动脉重塑和PH。具体目标1：明确PKCβ介导新生儿CH后基础张力增强和激动剂诱导的血管收缩剂敏感性的信号传导机制。 假设：新生儿CH通过PKCβ依赖性激活线粒体ROS生成和随后的VSM肌丝Ca 2+敏化增加肺血管收缩剂敏感性。具体目标二：确定PKCβ信号传导在CH诱导的新生儿PH发展中的作用。假设：PKCβ/mitoROS信号传导轴通过VSM中的收缩和促有丝分裂作用促进CH诱导的新生儿PH的发展和维持。 为了检验这些假设，协议将采用各种实验准备单细胞成像视频显微镜加压小肺动脉对照和CH新生大鼠。我们还将确定PKCβ和mitoROS对新生儿PH发展的意义。这项研究在研究肺循环特有的新信号传导机制以及该途径在CH诱导的新生儿PH发展中的作用方面具有创新性。这项研究具有重要意义，因为它有望垂直影响我们对新生儿PH机制的理解，因此有可能为PH以及其他PKCβ信号传导起核心作用的心血管和代谢疾病提供新的治疗策略。

 DESCRIPTION (provided by applicant): Pulmonary hypertension (PH) is a significant source of morbidity and mortality in infants. Although vasoconstriction is widely recognized as a critical mediator of neonatal PH, little is known regarding mechanisms of vasoconstriction in this setting, and current vasodilator therapies are largely ineffective. The overall objective of the current application is to identify vascular smooth muscle (VSM) signaling mechanisms responsible for PKC-mediated pulmonary vasoconstriction, and the role of this signaling pathway in chronic hypoxia (CH)-dependent increases in vasoconstrictor reactivity, arterial remodeling, and PH in neonates. Based on preliminary studies, our central hypothesis is that neonatal CH mediates spontaneous pulmonary arterial tone, enhanced agonist-induced pulmonary vasoconstrictor sensitivity, arterial remodeling and PH through PKCβ-induced mitochondrial ROS (mitoROS) signaling in pulmonary VSM. The following specific aims will be pursued: Specific Aim 1: Define the signaling mechanism by which PKCβ mediates enhanced basal tone and agonist-induced vasoconstrictor sensitivity following CH in neonates. Hypothesis: Neonatal CH augments pulmonary vasoconstrictor sensitivity via PKCβ dependent activation of mitoROS generation and subsequent VSM myofilament Ca2+ sensitization. Specific Aim 2: Determine the role of PKCβ signaling in the development of CH-induced neonatal PH. Hypothesis: The PKCβ/mitoROS signaling axis contributes to the progression and maintenance of CH- induced PH in neonates through both contractile and mitogenic actions in VSM. To test these hypotheses, protocols will employ a variety of experimental preparations from single cell imaging to video-microscopy of pressurized small pulmonary arteries from control and CH neonatal rats. We will also determine the significance of PKCβ and mitoROS to the development of neonatal PH. This research is innovative in its investigation of a novel signaling mechanism that is unique to the pulmonary circulation, and the role of this pathway in the development of CH-induced neonatal PH. This study is significant because it is expected to vertically impact our understanding of mechanisms that contribute to PH in the neonate, and therefore has potential to yield new treatment strategies for PH and other cardiovascular and metabolic disorders in which PKCβ signaling is a central player.