Inhibition of lupus nephritis in IRF-1 deficient mice

描述（由申请人提供）： MRL/Ipr小鼠自发地发展类似于人类狼疮的免疫复合物肾小球肾炎。在明显的疾病表现之前，MRL/lpr小鼠过度产生一氧化氮（NO），继发于诱导型一氧化氮合酶（iNOS）的基因表达增加。阻断iNOS β可减少MRL/lpr小鼠的疾病表达。巨噬细胞和系膜细胞都对IFN-γ产生应答，iNOS的产生增加，并且这种应答可以通过添加TNF-α进一步增强。IFN-γ构成最有效的巨噬细胞活化因子之一。IFN-7或IFN-γ受体基因缺失调节狼疮小鼠的疾病活动，尽管在这些基因敲除中注意到其他不良影响。系膜细胞是肾小球中主要的免疫调节细胞，具有巨噬细胞和平滑肌细胞的特性。除了表达Fc受体之外，系膜细胞含有结合细胞因子和趋化因子的受体，包括IFN-γ和TNF-α的受体。 IFN-γ与其受体的结合诱导包括IFN-γ调节因子1（IRF-1）在内的各种基因的转录。 IFN-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、血管细胞粘附分子1、干扰素-β、主要组织相容性复合物I和iNOS。 由IRF-1激活引发的导致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可能成为阻断狼疮肾脏炎症的新机制。 下文描述的具体目的是研究IFN-γ信号传导的作用并确定IRF-1在MRL/lpr小鼠中狼疮性肾炎中的作用。 具体目标1：确定IFN-γ、IRF-1和NF-κ B激活对系膜细胞中炎症介质产生（包括iNOS、IL-12、COX 2和TNF-c）的关系。我们还将确定特异性免疫调节剂对来自MRL/lpr IRF-1（-/-，+/-，+/+），B6 IRF-1（-/-）和对照的巨噬细胞和系膜细胞中IFN-γ信号传导和IRF-1表达的影响，野生型小鼠用LPS/TNF-α刺激。 具体目标二：通过将C57 BL 6（IRF-1- /-）小鼠回交到MRL/lpr背景上来研究IRF-1基因缺失对MRL/lpr小鼠的体内影响。

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.