Quantitative analysis of the renal pelvic and bladder urinary proteome

Urine proteome is a valuable reservoir of biomarkers for disease diagnosis and monitoring. Following its formation as the plasma filtrate in the kidney, urine is progressively modified by the active reabsorption and secretion of the cells lining the urinary tract. However, little is known about how the urine proteome changes as it passes along the urinary tract. To investigate this, we compared the proteome composition of renal pelvis urine (RPU) and individually self-voided bladder urine (BU) collected from 7 one-side urinary tract obstruction male patients. While no exclusive proteins were observed for either type of urine sample, BU had more proteins that were overrepresented at a higher frequency than RPU. Furthermore, the label-free quantitative analysis indicated that the BU proteome has a higher diversity in dominant proteins in conjunction with more upregulated proteins. Functional annotation revealed the BU-RPU differential proteins are enriched in exosomes and extracellular proteins, indicating active urothelial-urinary interactions. These differential proteins can facilitate biomarker discovery for diseases affecting the urinary tract.