Inhibition of lupus nephritis in IRF-1 deficient mice

描述(由申请人提供)： MRL/IPR小鼠自发地发展成类似人类狼疮的免疫复合体肾炎。在明显的疾病表现之前，MRL/LPR小鼠继发于诱导型一氧化氮合酶(INOS)基因表达增加而过度产生一氧化氮(NO)。阻断iNOS在药理上减少MRL/LPR小鼠的疾病表达。巨噬细胞和系膜细胞都对干扰素-γ作出反应，诱导型一氧化氮合酶的产生增加，而这种反应可以通过添加肿瘤坏死因子-α来进一步增强。干扰素-γ是最有效的巨噬细胞激活因子之一。干扰素-7或干扰素-γ受体基因缺失都可以调节狼疮小鼠的疾病活动性，尽管在这些基因敲除中也注意到了其他不利影响。肾小球系膜细胞是肾小球的主要免疫调节细胞，兼具巨噬细胞和平滑肌细胞的特性。除了表达Fc受体外，系膜细胞还含有结合细胞因子和趋化因子的受体，包括干扰素-γ和肿瘤坏死因子-α受体。干扰素-γ与其受体结合可诱导多种基因的转录，包括干扰素-γ调节因子-1(IRF-1)。干扰素-γ在巨噬细胞和系膜细胞中的许多炎症作用是通过IRF-1介导的，包括上调IL-12、血管细胞黏附分子1、干扰素-p、主要组织相容性复合体I和iNOS。IRF-1激活导致iNOS表达的分子事件尚未完全阐明。我们假设IRF-1在狼疮小鼠肾脏炎症反应的启动和传播中起关键作用。因此，靶向IRF-1可能是阻断狼疮肾炎症的一种新机制。下面描述的特定目的是研究干扰素-γ信号的作用，并确定IRF-1在MRL/LPR小鼠狼疮性肾炎中的作用。具体目的1：探讨干扰素-γ、IRF-1与NFKB活化对系膜细胞产生炎症介质iNOS、IL-12、COX2、TNF-c的关系。我们还将从MRL/LPR IRF-1(-/-，+/-，+/+)、B6 IRF-1(-/-)和对照野生型小鼠(LPS/TNF-oc)刺激的巨噬细胞和系膜细胞中，检测特定免疫调节剂对巨噬细胞和系膜细胞中干扰素-γ信号和IRF-1表达的影响。特定目的2：通过将C57BL6(IRF-1-/-)小鼠回交到MRL/LPR小鼠的背景上，研究IRF-1基因缺失对MRL/LPR小鼠体内的影响。

DESCRIPTION (provided by applicant): MRL/Ipr mice spontaneously develop immune complex glomerulonephritis similar to human lupus. Prior to overt disease manifestations, MRL/lpr mice overproduce nitric oxide (NO) secondary to increased gene expression of inducible nitric oxide synthase (iNOS). Blockade of iNOS pharmacologically reduces disease expression in MRL/lpr mice. Both macrophages and mesangial cells respond to IFN-gamma with increased production of iNOS and this response can be potentiated further by the addition of TNF-a. IFN-gamma constitutes one of the most potent macrophage activating factors. Either IFN-7 or IFN-y receptor gene deletion modulates disease activity in lupus mice although other adverse effects in these genetic knockouts were noted. Mesangial cells are the principal immunoregulatory cells in the glomerulus possessing both macrophage and smooth muscle cell characteristics. In addition to expressing Fc receptors, mesangial cells contain receptors that bind cytokines and chemokines including receptors for IFN-gamma and TNF-oc. Binding of IFN-gamma to its receptor induces transcription of various genes including IFN-gamma regulatory factor 1 (IRF-1). Many of the inflammatory effects of IFN-gamma in macrophages and mesangial cells are mediated through IRF-1 including up-regulation of IL-12, vascular cell adhesion molecule 1, interferon-p, major histocompatability complex I, and iNOS. The molecular events triggered by IRF-1 activation leading to iNOS expression are not completely elucidated. We hypothesize that IRF-1 plays a key role in the initiation and propagation of the inflammatory response in the murine lupus kidney. Targeting IRF-1 may thus serve as a novel mechanism for blocking inflammation in the lupus kidney. The specific aims described below investigate the role of IFN-y signaling and define the role of IRF-1 in lupus nephritis in MRL/lpr mice. Specific Aim 1: Determine the relationship between IFN-gamma, IRF-1 and NFKB activation on inflammatory mediator production including iNOS, IL-12, COX2, and TNF-c in mesangial cells. We will also determine the effects of specific immune modulators on IFN-y signaling and IRF-1 expression in macrophages and mesangial cells from MRL/lpr IRF-1 (-/-, +/-, +/+), B6 IRF-1 (-/-) and control, wiId type mice stimulated with LPS/TNF-oc. Specific Aim 2: Study the in vivo effect of gene deletion of IRF-1 on MRL/lpr mice by backcrossing C57BL6 (IRF-1- /-) mice onto the MRL/lpr background.