Label-free quantitative proteomics reveals differentially regulated proteins influencing urolithiasis.

Area of Science:

• Urology
• Proteomics
• Biochemistry

Background:

• Urinary proteins play a role in inhibiting kidney stone formation (urolithiasis).
• Urine proteomic analysis offers insights into urologic conditions but requires concentration normalization.
• Total protein to creatinine ratio was used to normalize urinary protein concentration variations.

Purpose of the Study:

• To characterize and quantify differences in the urinary proteome between kidney stone formers and non-stone-forming controls.
• To identify specific proteins associated with urolithiasis.
• To investigate the functional role of identified proteins in kidney stone formation.

Main Methods:

• Label-free nano-ultraperformance liquid chromatography-high/low collision energy switching analysis was employed.
• Pooled urine samples from stone formers and controls were compared in two independent experiments.
• Enzyme-linked immunosorbent assay (ELISA) and in vitro crystallization assays were used for validation.

Main Results:

• 1063 proteins were identified; 367 were unique to stone formers and 408 to controls.
• Proteins unique to stone formers were linked to carbohydrate metabolism and disease states.
• Ceruloplasmin was significantly upregulated in stone formers and promoted calcium oxalate crystal formation in vitro.

Conclusions:

• Urinary proteomic differences exist between kidney stone formers and controls.
• Ceruloplasmin may play a functional role in the development of urolithiasis.
• These findings contribute to understanding the molecular mechanisms of kidney stone disease.