Effects of Three Commonly-used Diuretics on the Urinary Proteome

Biomarker is the measurable change associated with a physiological or pathophysiological process. Unlike blood which has mechanisms to keep the internal environment homeostatic, urine is more likely to reflect changes of the body. As a result, urine is likely to be a better biomarker source than blood. However, since the urinary proteome is affected by many factors, including diuretics, careful evaluation of those effects is necessary if urinary proteomics is used for biomarker discovery. Here, we evaluated the effects of three commonly-used diuretics （furosemide, F; hydrochlorothiazide, H; and spirolactone, S） on the urinary proteome in rats. Urine samples were collected before and after intragastric administration of diuretics at therapeutic doses and the proteomes were analyzed using label-free liquid chromatography-tandem mass spectrometry （LC-MS/MS）. Based on the criteria of P ≤ 0.05, a fold change ≥2, a spectral count ≥ 5, and false positive rate （FDR） ≤1%, 14 proteins （seven for F, five for H, and two for S） were identified by Progenesis LC-MS. The human orthologs of most of these 14 proteins are stable in the healthy human urinary proteome, and ten of them are reported as disease biomarkers. Thus, our results suggest that the effects of diuretics deserve more attention in future urinary protein biomarker studies. Moreover, the distinct effects of diuretics on the urinary proteome may provide clues to the mechanisms of diuretics.

In-depth urinary and exosome proteome profiling analysis identifies novel biomarkers for diabetic kidney disease

Diabetic kidney disease(DKD)is a major microvascular complication of type 2 diabetes mellitus(T2DM).Monitoring the early diagnostic period and disease progression plays a crucial role in treating DKD.In this study,to comprehensively elucidate the molecular characteristics of urinary proteins and urinary exosome proteins in type 2 DKD,we performed large-scale urinary proteomics(n=144)and urinary exosome proteomics(n=44)analyses on T2DM patients with albuminuria in varying degrees.The dynamics analysis of the urinary and exosome proteomes in our study provides a valuable resource for discovering potential urinary biomarkers in patients with DKD.A series of potential biomarkers,such as SERPINA1 and transferrin(TF),were detected and validated to be used for DKD diagnosis or disease monitoring.The results of our study comprehensively elucidated the changes in the urinary proteome and revealed several potential biomarkers reflecting the progression of DKD,which provide a reference for DKD biomarker screening.

Urinary proteomics as a novel tool for biomarker discovery in kidney diseases

Urine has become one of the most attractive biofluids in clinical proteomics,for its procurement is easy and noninvasive and it contains sufficient proteins and peptides. Urinary proteomics has thus rapidly developed and has been extensively applied to biomarker discovery in clinical diseases,especially kidney diseases. In this review,we discuss two important aspects of urinary proteomics in detail,namely,sample preparation and proteomic tech-nologies. In addition,data mining in urinary proteomics is also briefly introduced. At last,we present several successful examples on the application of urinary proteomics for biomarker discovery in kidney diseases,including diabetic nephropathy,IgA nephropathy,lupus nephritis,renal Fanconi syndrome,acute kidney injury,and renal allograft rejection.