TNF-like weak inducer of apoptosis (TWEAK) signaling: a novel therapeutic target

描述(申请人提供)：尽管侵袭的巨噬细胞和肾小球细胞在狼疮性肾炎(LN)的发病机制中都是至关重要的，狼疮性肾炎(LN)是SLE最常见和最危险的临床表现之一，但它们之间的相互作用仍然不完全清楚。了解巨噬细胞和肾脏细胞的相对作用及其相互作用，将有助于我们理解LN的发病机制，并为更有针对性的治疗提供机会。肿瘤坏死因子受体超家族成员及其同源配体的异常相互作用被认为在狼疮发病机制中起核心作用。抑制其中几个配体/受体对已经在人类狼疮的临床试验中显示出希望。TWINE是肿瘤坏死因子配体超家族中的一个分泌型细胞因子。TWEAM与其受体Fn14结合，刺激巨噬细胞、成纤维细胞、滑膜细胞和内皮细胞分泌趋化因子、细胞因子和其他促炎介质。我们的初步结果提示TWEEP/Fn14信号在LN的发病机制中起重要作用：1.人LN患者尿液中TWEK水平升高，并与疾病活动相关；2.TWEEP受体Fn14在体外表达于小鼠和人肾小球系膜细胞(MC)和足细胞，在体内表达于狼疮肾。用TWAKE处理足细胞可增加关键致病细胞因子的表达，包括MCP-1、RANTES、VCAM-1和IP-10。肾脏中MCP-1的增加导致炎症细胞的募集和局部炎症过程的放大；3.B6小鼠注射TWEK可增加MCP-1的表达，促进T细胞和巨噬细胞向肾脏的趋化，并刺激肾小球细胞增殖；4.初步研究表明，抗TWEK抗体在减少SLE慢性移植物抗宿主小鼠模型中的蛋白尿方面具有良好的效果。我们的假设是，阻断TWEKE-Fn14信号将有益于治疗小鼠LN，并且TWEEP激活巨噬细胞和常驻肾细胞是该细胞因子在狼疮炎症性肾脏疾病中所起作用的中心。我们提出这一建议的具体目的如下：1.研究TWEW-Fn14信号在LN发病机制中的直接作用，并通过a)确定Fn14缺乏的狼疮易感MRL-LPR/LPR(MRL-LPR)小鼠的特征；b)给狼疮易感小鼠注射抗TWEK的单抗；ii.鉴定巨噬细胞中TWEK激活在LN发病中的相对贡献；III.确定TWEAM信号在LN的发生发展中的作用，包括蛋白尿和肾小球硬化。 与公共卫生相关：作为肿瘤坏死因子家族蛋白质的一种细胞因子，对包括小鼠和人类肾细胞在内的几种不同类型的细胞都有许多促炎作用。TWEK诱导的一些炎症介质在狼疮影响的肾脏中观察到的炎症中起着重要作用。我们的目标是研究TWINE与其受体在狼疮不同细胞类型上的结合的重要性，并探索抗TWINE抗体是否有助于治疗肾脏炎症。

DESCRIPTION (provided by applicant): While both infiltrating macrophages and glomerular cells are crucial in the pathogenesis of lupus nephritis (LN), one of the most common and dangerous clinical manifestations of SLE, their interactions remain incompletely understood. Appreciating the relative contribution of macrophages and resident kidney cells, and their interactions, would help us to understand the pathogenesis of LN and could provide an opportunity for more targeted therapies. Abnormal interaction of TNF-receptor superfamily members and their cognate ligands are believed to play a central role in lupus pathogenesis. Inhibition of several of these ligand/receptor pairs has already shown promise in clinical trials in human lupus. TWEAK is a secreted cytokine member of the TNF-ligand superfamily. TWEAK binds to its receptor, Fn14, and stimulates macrophages, fibroblasts, synoviocytes, and endothelial cells to secrete chemokines, cytokines, and other proinflammatory mediators. Our preliminary results suggest that TWEAK/Fn14 signaling is essential in the pathogenesis of LN: 1. Urinary TWEAK levels are increased in human LN, and correlate with disease activity; 2. The TWEAK receptor, Fn14, is expressed by murine and human mesangial cells (MC) and podocytes in vitro, and in lupus kidneys in vivo. Treatment of podocytes with TWEAK leads to increased expression of key pathogenic cytokines, including MCP-1, RANTES, VCAM-1, and IP-10. Increased MCP-1 in the kidney leads to recruitment of inflammatory cells and amplification of the local inflammatory process; 3. Injection of TWEAK to B6 mice increases MCP-1 expression, promotes chemotaxis of T cells and macrophages into the kidney, and stimulates glomerular cell proliferation; 4. Preliminary studies show a beneficial effect of anti-TWEAK antibodies in reducing proteinuria in the chronic graft versus host murine model of SLE. Our hypotheses are that blocking TWEAK-Fn14 signaling will be beneficial in treatment of murine LN, and that TWEAK activation of both macrophages and resident kidney cells is central in the contribution of this cytokine to inflammatory renal disease in lupus. Our Specific Aims for this proposal are as follows: I. Investigate the direct involvement of TWEAK-Fn14 signaling in the pathogenesis of LN and determine its therapeutic potential by a) characterizing lupus prone MRL-lpr/lpr (MRL-lpr) mice with Fn14 deficiency; and b) administering an anti- TWEAK monoclonal antibody (mAb) to lupus prone mice; II. Characterize the relative contribution of TWEAK activation in macrophages to the pathogenesis of LN; III. Determine the effect of TWEAK signaling in resident kidney cells, and particularly podocytes, in the development of LN, including albuminuria and glomerulosclerosis. PUBLIC HEALTH RELEVANCE: A cytokine member of the TNF family of proteins, has many pro-inflammatory effects on several different cell types including mouse and human kidney cells. Some of the inflammatory mediators induced by TWEAK are important in the inflammation observed in kidneys affected by lupus. Our goals for this proposal are to investigate the importance of TWEAK binding to its receptor on different cell types in lupus, and to explore whether an anti-TWEAK antibody may be helpful in treating kidney inflammation.