Antiatherogenic effects of neutrophil alpha defensins

描述(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的形成和动脉粥样硬化的保护。这项建议侧重于人类中性粒细胞(PMN)表达的主要蛋白质α-防御素(？-def)在免疫反应和动脉粥样硬化发生中的作用，这一作用在现有的动脉粥样硬化小鼠模型中被忽略，因为小鼠确实表达？-def，而在人类中，由于PMN在斑块中的寿命较短。我们已经证明，？-def在人类斑块中含量丰富，表明PMN被激活。为了研究？-def在体内慢性炎症和动脉粥样硬化形成中的作用，我们培育了在载脂蛋白E-/-(D+/+apoE-/-)上培养的中性粒细胞中表达人-def的新小鼠。在初步研究中，与高脂饮食的D-/-ApoE-/-对照小鼠相比，D+/+ApoE-/-小鼠表现出较少的动脉粥样硬化和减少全身炎症。这与最近的研究是一致的，这些研究与被广泛接受的？-def的促炎作用形成对比，证明了它对巨噬细胞和单核细胞的抗炎作用。此外，β-DEF还可抑制巨噬细胞中核因子-kB的激活，抑制人和小鼠巨噬细胞与基质蛋白的黏附，并增加炎症小鼠模型中单核细胞调节性驻留亚群的数量。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，在新生动脉粥样硬化病变中，活化的PMN释放的β-def通过抑制核因子-kB的激活和随后多种促炎细胞因子的表达，将单核/巨噬细胞亚群的分布从促炎调节为抗炎表型。为了验证这一假说，我们将研究？-def在体内对动脉粥样硬化和炎症的影响，并通过我们开发的新的def+/+小鼠中分离的？-def和中性粒细胞填充的？-def来阐明其在体内以及对单核细胞和巨噬细胞的作用机制。总之，这项建议是理解？-def在炎症中的关键作用的关键的第一步，并将提供一个范式转换，从被广泛接受的？-def的促炎作用，转变为在动脉粥样硬化的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.