Department II of Internal Medicine, University of Cologne, Cologne, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany; Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany; Systems Biology of Ageing Cologne (Sybacol), University of Cologne, Cologne, Germany.
Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany.
Kidney Int. 2018 Jun;93(6):1308-1319. doi: 10.1016/j.kint.2017.12.012. Epub 2018 Mar 9.
In diseases of many parenchymatous organs, heterogeneous deterioration of individual functional units determines the clinical prognosis. However, the molecular characterization at the level of such individual subunits remains a technological challenge that needs to be addressed in order to better understand pathological mechanisms. Proteinuric glomerular kidney diseases are frequent and assorted diseases affecting a fraction of glomeruli and their draining tubules to variable extents, and for which no specific treatment exists. Here, we developed and applied a mass spectrometry-based methodology to investigate heterogeneity of proteomes from individually isolated nephron segments from mice with proteinuric kidney disease. In single glomeruli from two different mouse models of sclerotic glomerular disease, we identified a coherent protein expression module consisting of extracellular matrix protein deposition (reflecting glomerular sclerosis), glomerular albumin (reflecting proteinuria) and LAMP1, a lysosomal protein. This module was associated with a loss of podocyte marker proteins while genetic ablation of LAMP1-correlated lysosomal proteases could ameliorate glomerular damage in vivo. Furthermore, proteomic analyses of individual glomeruli from patients with genetic sclerotic and non-sclerotic proteinuric diseases revealed increased abundance of lysosomal proteins, in combination with a decreased abundance of mutated gene products. Thus, altered protein homeostasis (proteostasis) is a conserved key mechanism in proteinuric kidney diseases. Moreover, our technology can capture intra-individual variability in diseases of the kidney and other tissues at a sub-biopsy scale.
在许多实质器官疾病中，个别功能单位的不均匀退化决定了临床预后。然而，在这种个别亚基水平上进行分子特征描述仍然是一个技术挑战，需要加以解决，以便更好地了解病理机制。蛋白尿性肾小球肾脏疾病是一种常见且多样化的疾病，影响肾小球及其引流小管的不同程度，目前尚无特异性治疗方法。在这里，我们开发并应用了一种基于质谱的方法来研究蛋白尿性肾脏疾病小鼠分离的单个肾单位的蛋白质组异质性。在两种不同的肾小球硬化性疾病小鼠模型的单个肾小球中，我们鉴定出一个由细胞外基质蛋白沉积（反映肾小球硬化）、肾小球白蛋白（反映蛋白尿）和溶酶体蛋白 LAMP1 组成的一致的蛋白质表达模块。该模块与足细胞标记蛋白的丢失有关，而 LAMP1 相关溶酶体蛋白酶的基因缺失可改善体内肾小球损伤。此外，对遗传性硬化性和非硬化性蛋白尿性肾脏疾病患者的单个肾小球进行蛋白质组学分析显示，溶酶体蛋白的丰度增加，同时突变基因产物的丰度降低。因此，改变的蛋白质内稳性（蛋白质稳态）是蛋白尿性肾脏疾病的一个保守的关键机制。此外，我们的技术可以在亚活检规模上捕获肾脏和其他组织疾病中的个体内变异性。
