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。尽管血管收缩被广泛认为是一种关键的 新生儿PH的中介物，对这种情况下血管收缩的机制知之甚少，目前的血管扩张剂治疗大多无效。目前应用的总体目标是确定负责PKC介导的肺血管收缩的血管平滑肌(VSM)信号机制，以及这一信号通路在慢性低氧(CH)依赖的血管收缩反应性、动脉重构和新生儿PH增加中的作用。在前期研究的基础上，我们的中心假设是，新生儿CH通过PKCβ诱导的线粒体ROS(MitoROS)信号在肺血管平滑肌中介导自发的肺动脉张力、增强的激动剂诱导的肺血管收缩敏感性、动脉重构和PH。将追求以下特定目标：特定目标1：明确PKCβ介导新生儿脑出血后基础张力和激动剂诱导的血管收缩敏感性增强的信号机制。假设：新生儿CH通过PKCβ依赖的丝裂原生成的激活和随后的VSM肌丝钙敏化来增加肺血管收缩敏感性。特异性目的2：确定蛋白激酶Cβ信号在CH诱导的新生儿PH发生发展中的作用。假设：PKCβ/mitoROS信号轴通过收缩和促有丝分裂两种作用参与CH诱导的新生儿PH的进展和维持。为了验证这些假说，实验方案将使用各种实验准备，从单细胞成像到对对照组和CH新生大鼠的加压小肺动脉的视频显微镜检查。我们还将确定PKC、β和丝裂原ROS在新生儿PH发生发展中的意义。这项研究的创新之处在于研究了一种独特于肺循环的新的信号机制，以及这一途径在CH诱导的新生儿PH发生中的作用。这项研究意义重大，因为它有望垂直影响我们对导致新生儿PH的机制的理解，因此有可能为PH和其他心血管和代谢疾病提供新的治疗策略，其中PKCβ信号是其中的核心参与者。

 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.