Kidney Keratins, endogenous cytoprotective factors?

角蛋白(K)是上皮细胞的中间丝（IFs）和细胞骨架的主要组成部分，提供了它们的机械完整性。角蛋白在各种应激情况下也具有细胞保护功能，对皮肤和胃肠道有最好的描述。肾小管细胞（TEC）是最丰富的肾上皮细胞。在几乎所有肾脏疾病中，TEC都暴露于许多应激刺激，并通过表型改变和细胞骨架重塑对其作出反应。我们最近发现，主要的肾角蛋白，如K7、K8、K18和K19，在不同的动物模型和肾损伤患者中都高度上调，可能作为TEC应激的新标志物。我们假设，角蛋白可能在TEC适应各种应激情况的过程中发挥主要的细胞保护作用，并促进TEC修复。我们的目标是在以下工作包中解决这一假设：我们将在体外比较野生型和各种角蛋白缺乏的原代小鼠TEC的生物力学特性、表型和促炎改变、再生潜力和存活率。在体内，我们将在健康小鼠和几种以TEC损伤和再生为特征的肾脏疾病模型中，分析整个角蛋白II基因簇缺失对TEC或单个主要肾角蛋白的影响。3. 我们将使用K8-eYFP报告小鼠在体内和体外分析角蛋白丝的动态。最后，我们的目标是确定翻译后修饰和潜在的新型肾角蛋白，并测试角蛋白作为TEC损伤特异性尿标志物的有效性。这些实验将为肾角蛋白的功能作用和诊断潜力提供第一个数据。

Keratins (K) are intermediate filaments (IFs) and a major component of the cell cytoskeleton of epithelial cells, providing for their mechanical integrity. Keratins also have cytoprotective functions in a variety of stress situations, best described for skin and the gastrointestinal tract. Tubular cells (TEC) are the most abundant renal epithelial cells. During virtually all kidney diseases TEC are exposed to a number of stress stimuli, to which they react by phenotypic alterations and cytoskeletal remodeling. We recently showed that the major renal keratins, i.e. K7, K8, K18 and K19, are highly up-regulated in different animal models and patients with kidney injury and could serve as novel markers of TEC stress. We hypothesize, that keratins may play a major cytoprotective role during the accommodation of TEC to a broad array of stress situations and that they promote TEC repair. We aim to tackle this hypothesis in the following work packages:1. We will compare wild-type and various keratin-deficient primary murine TEC in vitro with respect to biomechanical properties, phenotypic and pro-inflammatory alterations, regenerative potential and survival.2. In vivo, we will analyze the consequences of deletion of the whole keratin II gene cluster specifically in TEC or of single major renal keratins in healthy mice and in several renal disease models characterized by TEC injury and regeneration. 3. We will use the K8-eYFP reporter mice to analyze the dynamics of keratin filaments in vitro and in vivo.4. Finally, we aim to identify the post-translational modifications and potential novel kidney keratins and test the usefulness of keratins as specific urinary markers of TEC injury.These experiments will provide first data on the functional role and diagnostic potential of renal keratins.