Fibrinogen-Induced Vasoconstriction during Hypertension

描述（由申请人提供）：高血压伴血浆纤维蛋白原（Fg）含量升高。我们报道了Fg与动脉壁的结合引起血管收缩，这是由细胞间粘附分子-1 （ICAM-1）介导的。此外，内皮素A型受体的阻断可减弱fg诱导的血管收缩。在我们的初步研究中，Fg的内皮结合促进了内皮素-1 （ET-1）的产生。此外，Fg与内皮细胞（ECs）结合导致细胞外信号调节激酶（ERK）磷酸化。ICAM-1和另一种Fg内皮受体α 5beta1整合素的激活导致ERK和c- jun - nh2末端激酶（JNK）的磷酸化。高血压期间，fg诱导的血管收缩增加，并通过韦贝尔-帕拉德体（WPb）胞吐调节ET-1的产生。我们假设，在高血压期间，Fg与内皮细胞ICAM-1（可能还有alpha5beta1）结合增加，通过ERK（也可能是JNK）信号诱导WPbs的胞外分泌增强，并导致ET-1的产生增加，从而增强血管收缩。基于我们的发现，Fg与EC结合改变EC蛋白质组，这可能与WPb胞分泌有关，我们将确定这些Fg诱导的细胞变化是否与ET-1释放有关，从而与血管收缩有关。该研究的具体目的是：1)评估Fg与ICAM-1的结合，由此产生ET-1，以及高血压患者随后的血管收缩；2)确定高血压期间fg诱导的ET-1产生和血管收缩升高的信号通路（ERK-和/或jnk参与）；3)探讨经Fg结合改变的EC蛋白在高血压期Fg诱导的WPbs胞外分泌中的功能作用。高血压诱导的Fg与内皮细胞ICAM-1（和alpha5beta1）结合增强、ERK（和JNK）信号通路的作用以及Fg与内皮细胞结合改变的蛋白在WPbs的胞外分泌增加和ET-1的产生中所起的作用将被确定，从而导致血管收缩增强。遗传性（SHR）和非遗传性（DOCA-salt）大鼠高血压模型将在高血压的早期和建立阶段进行研究，以确定与高血压发展和维持相关的变化。本研究将描述在高血压期间，由fg调控的ET-1的产生以及由此导致的血管收缩加剧，从而加剧微循环并发症的机制。

DESCRIPTION (provided by applicant): Hypertension is accompanied by an increased content of plasma fibrinogen (Fg). We reported that binding of Fg to the arterial wall causes vasoconstriction, which is mediated by intercellular adhesion molecule-1 (ICAM-1). In addition, blockade of the endothelin type A receptors attenuated Fg-induced vasoconstriction. In our preliminary studies, endothelial binding of Fg enhanced production of endothelin-1 (ET-1). Furthermore, Fg binding to endothelial cells (ECs) resulted in phosphorylation of extracellular signal regulated kinase (ERK). Activation of ICAM-1 and another Fg endothelial receptor, alpha5beta1 integrin, leads to phosphorylation of ERK and c-Jun-NH2-terminal kinase (JNK). Fg-induced vasoconstriction is increased during hypertension, and regulated production of ET-1 results from exocytosis of Weibel-Palade bodies (WPb). We hypothesize that during hypertension, increased Fg binding to endothelial ICAM-1 (and possibly alpha5beta1) induces enhanced exocytosis of WPbs through ERK (and possibly JNK) signaling and results in increased production of ET-1 leading to enhanced vasoconstriction. Based on our finding that Fg binding to ECs changes EC proteome which may be associated with WPb exocytosis, we will determine if these Fg-induced cellular changes are associated with ET-1 release, and therefore with vasoconstriction. The specific aims of the proposed study are: 1) To evaluate Fg binding to ICAM-1, the resultant production of ET-1, and subsequent vasoconstriction during hypertension; 2) To determine the signaling pathway (ERK- and/or JNK-involved) for Fg-induced ET-1 production and the elevated vasoconstriction during hypertension; and 3) To determine the functional role of EC proteins altered by Fg binding in Fg-induced exocytosis of WPbs during hypertension. Hypertension-induced enhanced Fg binding to endothelial ICAM-1 (and alpha5beta1), the role of ERK (and JNK) signaling and the role of proteins altered by Fg binding to ECs in increased exocytosis of WPbs and production of ET-1, which causes enhanced vasoconstriction, will be determined. Genetic (SHR) and non-genetic (DOCA-salt) rat hypertension models will be studied at early and established stages of hypertension to identify changes associated with the development and maintenance of hypertension. This study will delineate mechanisms of Fg-regulated production of ET-1 and the resultant increased vasoconstriction that exacerbates microcirculatory complications during hypertension.