The role of neutrophil recruitment in arterial diseases

描述：动脉损伤后形成的病变和新生内膜是动脉粥样硬化的两种主要的动脉病理改变。这两种动脉病变是由白细胞向动脉血管壁募集引起的。这项研究的长期目标是确定中性粒细胞在动脉疾病发生中的作用。这一建议的中心假设是，中性粒细胞在动脉血管壁上的募集是中性粒细胞在动脉疾病发展中所必需的。与单核细胞在动脉疾病，特别是自发性病变的发展中的作用相比，中性粒细胞在这些动脉疾病中的参与是有争议的。然而，最近的一项研究报告称，中性粒细胞数量高的小鼠动脉粥样硬化增加，而使用中性粒细胞耗竭抗体治疗的小鼠动脉粥样硬化减少。尽管这项研究指出了中性粒细胞在动脉粥样硬化中的重要作用，但它所使用的方法改变了中性粒细胞的动态平衡，因此它未能在正常白细胞动态平衡的情况下，建立中性粒细胞重新聚集到动脉血管壁与动脉疾病的发展之间的直接联系。白细胞在动脉壁的募集是由白细胞系留和滚动启动的，后者是由白细胞选择素配体[P-选择素配体PSGL-1、E-选择素配体和L-选择素配体]介导的。选择素配体的糖基化是选择素配体与选择素结合的关键。Core2 1-6-N-氨基葡萄糖基转移酶-I(C2GlcNAcT-I)是介导选择素配体糖基化的酶之一。我们以前的研究表明，C2GlcNAcT-I基因的敲除几乎完全消除了白细胞对动脉血管壁的募集，并抑制了小鼠自发的和新的内膜病变的形成。我们最近获得了中性粒细胞特异性的Cre转基因小鼠，其中Cre重组酶和EGFP的表达是由髓过氧化物酶(MPO)基因的调节区驱动的(MPO-Cre小鼠)。通过用C2GlcNAcT-I小鼠培育这些MPO-CRE小鼠，我们产生了C2GlcNAcT-I缺乏的小鼠，特别是在中性粒细胞上。也产生了中性粒细胞特异性缺乏C2GlcNAcT-I的APOE-/-小鼠(Neu-C2GlcNAcT-I-/-/apoE-/-小鼠)。我们发现这些小鼠的中性粒细胞不能与内皮细胞相互作用。本项目的目的是利用这些小鼠来研究中性粒细胞重新聚集到动脉血管壁对自发性动脉粥样硬化病变和新生内膜病变形成的影响。具体地说，在两个动脉疾病模型中，我们将检查中性粒细胞C2GlcNAcT-I缺乏是否影响apoE-/-小鼠动脉损伤后单核细胞和/或血小板到动脉血管壁的募集、内皮再生、自发性病变的形成和动脉新内膜的形成。这些研究将提供证据表明，抑制中性粒细胞募集到动脉是预防和治疗动脉疾病的可行方法。 公共卫生相关性：拟议研究的结果将证明中性粒细胞在动脉血管壁上的募集是否是中性粒细胞对动脉疾病发展的贡献所必需的。该项目的成功完成将为抑制中性粒细胞归巢到动脉血管壁作为预防和治疗动脉疾病的方法之一提供证据。

DESCRIPTION: Lesions and neointima that forms following arterial injury are two of the major arterial pathologies in atherosclerosis. These two arterial pathologies are initiated by the recruitment of leukocytes to the arterial vessel walls. The long-term goal of this research is to determine the role of neutrophils in the genesis of arterial diseases. The central hypothesis of this proposal is that neutrophil recruitment to arterial vessel walls is required for the contribution of neutrophils to the development of arterial diseases. In contrast to the well-documented effect of mononuclear cells on the development of arterial diseases, especially spontaneous lesions, the involvement of neutrophils in these arterial diseases is disputable. However, one recent study has reported increased atherosclerosis in mice with a high neutrophil count and decreased atherosclerosis in mice treated with a neutrophil depletion antibody. Although that study points to an important role of neutrophils in atherosclerosis, the approaches it used alter neutrophil homeostasis, and it thus fails to establish a direct link between neutrophil recruitment to the arterial vessel wall and the development of arterial diseases under normal leukocyte homeostasis. Leukocyte recruitment to the arterial vessel wall is initiated by leukocyte tethering and rolling; the latter are mediated by leukocyte selectin ligands [PSGL-1 (ligand for P-selectin) and ligands for E- and L-selectin]. Glycosylation of selectin ligands is crucial for the binding of selectin ligands to the selectins. Core2 1-6-N- glucosaminyltransferase-I (C2GlcNAcT-I) is one of the enzymes that mediate the glycosylation of selectin ligands. Our previous studies have shown that knockout of C2GlcNAcT-I almost completely eliminates leukocyte recruitment to arterial vessel walls and suppresses the formation of spontaneous and neointimal lesions in mice. We have recently generated neutrophil-specific Cre transgenic mice, mice in which the expression of Cre recombinase and EGFP are driven by the regulatory region of the myeloperoxidase (MPO) gene (MPO-Cre mice). By breeding these MPO-Cre mice with floxed C2GlcNAcT-I mice, we have generated mice with C2GlcNAcT-I deficiency specifically in neutrophils. ApoE-/- mice lacking C2GlcNAcT-I specifically in neutrophils (Neu-C2GlcNAcT-I-/-/apoE-/- mice) were also generated. We have found that neutrophils in these mice fail to interact with the endothelium. The goal of this project is to use these mice to investigate the effect of neutrophil recruitment to arterial vessel walls on the formation of spontaneous atherosclerotic lesions and neointimal lesions. Specifically, in two arterial disease models we will examine whether neutrophil C2GlcNAcT- I deficiency affects the recruitment of monocytes and/or platelets to the arterial vessel wall, endothelial regeneration, the formation of spontaneous lesions and arterial neointima following arterial injury in apoE-/- mice. These studies will provide evidence that inhibition of neutrophil recruitment to arteries is a viable approach to the prevention and treatment of arterial diseases. PUBLIC HEALTH RELEVANCE: Results from the proposed research will demonstrate whether neutrophil recruitment to the arterial vessel wall is required for the contribution of neutrophils to the development of arterial diseases. The successful completion of this project will provide evidence for the inhibition of neutrophil homing to arterial vessel walls as one of the approaches for the prevention and treatment of arterial diseases.