Human proximal tubular epithelial cells (PTEC) of the kidney are known to respond to and mediate the disease process in a wide range of kidney diseases, yet their exosomal production and exosome molecular cargo remain a mystery. Here we investigate, for the first time, the production and molecular content of exosomes derived from primary human PTEC cultured under normal and diseased conditions representing a spectrum of in vivo disease severity from early inflammation, experienced in multiple initial kidney disease states, through to hypoxia, frequently seen in late stage chronic kidney disease (CKD) due to fibrosis and vascular compromise. We demonstrate a rapid reproducible methodology for the purification of PTEC-derived exosomes, identify increased numbers of exosomes from disease-state cultures and identify differential expression levels of both known and unique miRNA and protein species from exosomes derived from different disease-culture conditions. The validity of our approach is supported by the identification of miRNA, proteins and pathways with known CKD associations, providing a rationale to further evaluate these novel and known pathways as targets for therapeutic intervention.

已知人类的肾近端肾小管上皮细胞（PTEC）在多种肾脏疾病中对疾病的反应和介导，但它们的外泌体产生和外泌体分子运输仍然是一个谜。在这里，我们首次调查了在正常和患病条件下培养的代表人类体内光谱的原代人PTEC衍生的外泌体的产生和分子含量疾病的严重程度从早期发炎开始，在多种初始肾脏疾病状态中经历，直至缺氧，由于纤维化和血管受损，在晚期慢性肾脏病（CKD）中经常见到。我们演示了纯化PTEC来源的外泌体的快速可重现的方法，从疾病状态的文化中识别出增加的外泌体数量，并从不同疾病培养条件衍生的外来体中识别已知和独特的miRNA和蛋白质种类的差异表达水平。我们的方法的有效性得到了与已知CKD关联的miRNA，蛋白质和途径的鉴定的支持，从而为进一步评估这些新颖的已知途径作为治疗干预的靶标提供了理论依据。