Antiatherogenic effects of neutrophil alpha defensins

描述（由申请人提供）：动脉粥样硬化是一种慢性炎症性疾病，是心血管疾病死亡的主要原因。最近的研究表明，单核细胞和巨噬细胞的异质性有助于动脉粥样硬化和动脉粥样硬化保护轴。这一建议的重点是α -防御素（α -防御素），人类多形核中性粒细胞（pmn）中表达的一种主要蛋白，在动脉粥样硬化的免疫反应和发生中所起的作用，这一作用在现有的动脉粥样硬化小鼠模型中被忽视，因为小鼠确实表达α -防御素，而在人类中，由于斑块中pmn的寿命较短。我们已经证明¿-def在人类斑块中丰富，表明PMNs激活。为了研究¿-def对体内慢性炎症和动脉粥样硬化发展的贡献，我们在ApoE-/- (D+/+ApoE-/-)上培育了在pmn中表达人类¿-def的新型小鼠。在初步研究中，与高脂肪饮食的D-/-ApoE-/-对照小鼠相比，D+/+ApoE-/-小鼠显示出更少的动脉粥样硬化和更少的全身炎症。这与最近的研究一致，这些研究与广泛接受的_ -def的促炎作用形成对比，记录了对巨噬细胞和单核细胞的抗炎作用。此外，¿-def抑制巨噬细胞NF-kB的激活，抑制人和小鼠巨噬细胞对基质蛋白的粘附，并增加炎症小鼠模型中单核细胞调节常驻亚群的数量。总之，这些数据支持¿-def在体内具有抗炎、抗动脉粥样硬化的作用。我们假设，新生动脉粥样硬化病变中活化PMNs释放的¿-def通过抑制NF-kB激活和随后多种促炎细胞因子的表达，调节单核/巨噬细胞亚群从促炎表型到抗炎表型的分布。为了验证这一假设，我们将在体内研究¿-def对动脉粥样硬化和炎症的影响，并利用我们开发的新型def+/+小鼠中分离的¿-def和中性粒细胞包装的¿-def阐明其在体内和对单核细胞和巨噬细胞的作用机制。总之，这一建议是理解¿-def在炎症中的关键作用的关键一步，并将提供一个范式转变，从广泛接受的¿-def的促炎作用，到在动脉粥样硬化慢性炎症条件下的免疫调节剂或抗炎作用。

DESCRIPTION (provided by applicant): Atherosclerosis is a chronic inflammatory disease and is a leading cause of mortality in cardiovascular diseases. Recent studies demonstrate that monocytes and macrophage heterogeneity contribute to atherogenic and atheroprotective axes. This proposal focuses on the role that alpha-defensin (¿-def), a major protein expressed in human polymorphonuclear neutrophils (PMNs), plays in the immune response and genesis of atherosclerosis, a role that has been ignored in existing murine models of atherosclerosis because mice do express ¿-def, and in humans due to the short lifespan of PMNs in the plaque. We have shown that ¿-def is abundant in human plaques indicative of PMNs activation. To study the contribution of ¿-def to chronic inflammation and development of atherogenesis in vivo, we generated novel mice that express human ¿-def in their PMNs bred onto ApoE-/- (D+/+ApoE-/-). In preliminary studies D+/+ApoE-/- mice showed less atherosclerosis and reduced systemic inflammation compared with D-/-ApoE-/- control mice on a high fat diet. This is in line with recent studies that contrast with the widely accepted pro-inflammatory role of ¿-def, documented anti-inflammatory effects on macrophages and monocytes. Moreover, ¿-def inhibits activation of NF-kB in macrophages, inhibits adhesion of human and mouse macrophages to matrix proteins and increases the number of the regulatory resident subset of monocytes in inflammation mouse model. Together, these data support an anti-inflammatory, anti-atherogenic role for ¿-def in vivo. We hypothesized that ¿-def released from activated PMNs in nascent atherosclerotic lesions modulate the monocytes/macrophage subset distribution from a pro-inflammatory to an anti-inflammatory phenotype by inhibiting NF-kB activation and the subsequent expression of multi pro-inflammatory cytokines. To test this hypothesis, we will study the effect of ¿-def on atherosclerosis and inflammation in vivo and elucidate its mechanism of action both in vivo and on monocytes and macrophages using isolated ¿-def and neutrophils packed ¿-def in novel def+/+ mice that we developed. In sum, this proposal is a critical initial step to understand the critical role that ¿-def plays in inflammatio, and will provide a paradigm-shifting from, the widely accepted proinflammatory role of ¿-def, into immune modulator or anti-inflammatory role under conditions of chronic inflammation in atherosclerosis. PUBLIC HEALTH RELEVANCE: This proposal focuses on the role that alpha-defensin, a major protein expressed in human but not mice neutrophils, plays in the immune response and genesis of atherosclerosis. We will use a novel transgenic mouse to elucidate the pathways by which these peptides modulate the immune response in atherosclerosis.