Participation of cold shock DNA-binding protein-A in inflammatory kidney diseases

DNA结合蛋白-A(DbpA)属于人类冷休克蛋白超家族，具有与肝纤维化、肿瘤发生和转录/翻译调节相关的功能。有证据表明DbpA与活化的、增殖的肾小管细胞表型有关。除了参与与紧密连接相关的复合体的形成外，我们的数据还表明线粒体和外切体具有功能。此外，DbpA蛋白分泌活跃，例如在系膜增生性肾炎中。两种冷休克蛋白，Y-box结合蛋白-1(YB-1)和DbpA的联合作用，导致侵袭性的，支持迁移的细胞表型。目前的提案侧重于炎症性肾脏疾病(如单侧输尿管肾病、肾毒性肾炎和糖尿病肾病)，旨在探讨DBPA的功能作用和参与(S)。我们将确定(I)细胞内和细胞外DbpA所完成的功能。对于细胞内的DbpA，其参与线粒体能量稳态的机制将被阐明。此外，将建立一个可能影响细胞内信号/细胞命运决定的细胞表面受体的搜索。(Ii)在确定DbpA和YB-1的相互作用组中存在重叠后，我们将表征这两种蛋白质的细胞外和细胞内相互作用，并将其与功能联系起来。此外，还将研究胞外体DbpA对细胞增殖、促炎和纤维化细胞表型的贡献。(Iii)我们会澄清基因切除DbpA对肾脏疾病的炎症反应/转归有何影响。(4)初步数据表明，DbpA在白细胞中的表达水平受到高度调控，同时血清中含有大量的蛋白质。我们的任务是确定循环免疫细胞中DbpA的表达受哪些刺激的调节。鉴于对冷休克蛋白的自身免疫反应已经建立，我们将检测针对DbpA的自身抗体。该提案解决了关于冷休克蛋白DbpA在炎症性肾脏疾病发病机制中的功能作用(S)的关键问题。鉴于DbpA在系膜细胞和肾小管上皮细胞中的表达改变对细胞的显着影响，我们的追求是利用这些发现来开发诊断和治疗策略。

DNA binding protein-A (DbpA) belongs to the human cold shock protein superfamily with known functions related to fibrogenesis, cancerogenesis and transcriptional/translational regulation. Evidences link DbpA with an activated, proliferative tubular cell phenotype. Beyond its participation in tight junction-related complex formation, our data suggest mitochondrial and exosomal functions. Furthermore, DbpA protein is actively secreted, e.g. in mesangioproliferative nephritis. The combined effects of two cold shock proteins, Y-box binding protein-1 (YB-1) and DbpA, results in an invasive, pro-migratory cell phenotype. The current proposal focuses on inflammatory kidney diseases (such as unilateral ureteral nephropathy, nephrotoxic nephritis and diabetic nephropathy) and aims to investigate the functional role(s) and participation of DbpA. We will determine (i) functions fulfilled by intra- and extracellular DbpA. For intracellular DbpA its participation in mitochondrial energy homeostasis will be clarified. Furthermore a search for cell surface receptors will be set up that may affect intracellular signaling/cell fate decision. (ii) Having identified an overlap in the interactome of DbpA and YB-1, we will characterize extra- and intracellular interactions of both proteins and relate these to functions. Additionally the contribution of exosomal DbpA to cell proliferation, pro-inflammatory and -fibrotic cell phenotypes will be investigated. (iii) We will clarify how genetic ablation of DbpA affects the inflammatory response/outcome of kidney diseases. (iv) Finally, preliminary data indicate that DbpA expression levels in leukocytes is highly regulated, at the same time serum contains significant protein amounts. Our quest is to determine by which stimuli the DbpA expression is regulated in circulating immune cells. Given autoimmune responses against cold shock proteins are established we will test for autoantibodies against DbpA.The proposal addresses pivotal questions on the functional role(s) of the cold shock protein DbpA in the pathogenesis of inflammatory kidney diseases. Given the marked cellular effects seen with modification of DbpA expression in mesangial and tubular cells our quest is to harness the findings to develop diagnostic and therapeutic strategies.