Role of DPPI & Serine Proteases in Inflammatory Diseases

炎症过程中的神经元迁移是一个高度调节的过程，对于宿主防御入侵生物至关重要。 然而，中性粒细胞的过度积累和活化可导致破坏性作用。中性粒细胞丝氨酸蛋白酶[中性粒细胞弹性蛋白酶（NE）、组织蛋白酶G（CG）、蛋白酶3（PR 3）]在成熟中性粒细胞中特异性表达。 我们最近创建了一个小鼠的溶酶体半胱氨酸蛋白酶二肽基肽酶I（DPPI）的无效突变。 我们发现DPPI是许多丝氨酸蛋白酶包括NE、CG和PR 3的加工和活化所必需的。此外，我们的初步结果表明，DPPI缺陷型和NE × CG缺陷型小鼠对被动转移单克隆抗体至II型胶原蛋白诱导的急性关节炎具有保护作用。 具体而言，蛋白酶缺陷小鼠的关节中没有中性粒细胞的积聚。 这些结果支持DPPI（可能通过NE和CG的作用）在特定炎症部位的中性粒细胞迁移和/或中性粒细胞募集中发挥非冗余作用的假设。 因此，我们提出以下具体目标：1。我们将定义DPPI和丝氨酸蛋白酶在中性粒细胞迁移中的作用。 神经元迁移需要几种粘附分子的活化和相互作用。 在这个特定的目标，我们将检查的表达粘附分子L-选择素和β 2整合素激活LPS。 我们还将研究DPPI和丝氨酸蛋白酶在体外中性粒细胞粘附和迁移中的需求。2.我们将定义DPPI和丝氨酸蛋白酶在急性关节炎模型中的体内作用。 我们的初步研究结果表明，有一个主要的缺陷，中性粒细胞的迁移或继发性缺陷，中性粒细胞的激活和招聘在炎症部位。 在这个目标中，我们将描述DPPI缺陷小鼠对关节内IL-8的直接反应。 我们还将通过骨髓移植建立嵌合小鼠，以确定炎症部位野生型中性粒细胞的积累和活化是否足以招募DPPI缺陷型中性粒细胞。3.我们将探索嗜中性粒细胞衍生的丝氨酸蛋白酶在其他急性和慢性炎症模型中的作用。 在这个目标中，我们将确定中性粒细胞迁移/募集的缺陷是否会推广到其他器官，如皮肤。 此外，我们还将研究另外两种关节炎模型，一种是脓毒性关节炎，另一种涉及慢性炎症。

Neutrophil emigration during inflammation is a highly regulated process and is critical for host defense against invading organisms. However, excessive accumulation and activation of neutrophils can lead to damaging effects. Neutrophil serine proteases [neutrophil elastase (NE), cathepsin G (CG), proteinase 3 (PR3) are expressed specifically in mature neutrophils. We have recently created a mouse with a null mutation in the lysosomal cysteine protease dipeptidyl peptidase I (DPPI). We showed that DPPI is required for the processing and activation of many serine proteases including NE, CG, and PR3. Furthermore, our preliminary results indicate that the DPPI- deficient and NE x CG-deficient mice are protected against acute arthritis induced by passive transfer of monoclonal antibodies to type II Collagen. Specifically, there is no accumulation of neutrophils in the joints of protease-deficient mice. These results support the hypothesis that DPPI (probably through the action of NE and CG) plays a non-redundant role in neutrophil emigration and/or neutrophil recruitment at specific inflammatory sites. Thus, we propose the following specific aims: 1. We will define the role(s) of DPPI and serine proteases in neutrophil migration. Neutrophil migration requires the activation and interaction of several adhesion molecules. In this specific aim, we will examine the expression of adhesion molecules L-selectin and beta2 integrins upon activation with LPS. We will also examine the requirement for DPPI and serine proteases in neutrophil adhesion and transmigration in vitro. 2. We will define the in vivo role(s) of DPPI and serine proteases in the model of acute arthritis. Our preliminary results suggest that there is either a primary defect in neutrophil emigration or a secondary defect in neutrophil activation and recruitment at sites of inflammation. In this aim, we will characterize the direct response of DPPI-deficient mice to intra-articular IL-8. We will also establish chimeric mice by bone marrow transplantation to determine whether accumulation and activation of wild type neutrophils at sites of inflammation will be sufficient to recruit DPPI-deficient neutrophils. 3. We will explore the role(s) of neutrophil-derived serine proteases in other models of acute and chronic inflammation. In this aim, we will determine whether the defect in neutrophil emigration/recruitment is generalized to other organs, such as skin. In addition, we will also study two additional arthritis models, one of septic arthritis and the other involving chronic inflammation.