Noninvasive Biomarker Candidates for Cadmium-Induced Nephrotoxicity by 2DE/MALDI-TOF-MS and SILAC/LC-MS Proteomic Analyses

• Published in: Toxicological sciences 2015-11, Vol.148 (1), p.167-182
• Main Authors: Kim, Sun Young, Lee, Hye Min, Kim, Kyeong Seok, Kim, Hyung Sik, Moon, Aree
• Format: Article
• Language: English
• Subjects: Animals; Biomarkers - metabolism; Biomarkers - urine; Cadmium Chloride - toxicity; Cadmium Poisoning - metabolism; Cadmium Poisoning - pathology; Cadmium Poisoning - physiopathology; Cadmium Poisoning - urine; Cell Adhesion - drug effects; Cell Line; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Electrophoresis, Gel, Two-Dimensional; Gene Expression Profiling; HSC70 Heat-Shock Proteins - chemistry; HSC70 Heat-Shock Proteins - genetics; HSC70 Heat-Shock Proteins - metabolism; HSC70 Heat-Shock Proteins - urine; Humans; Isotope Labeling; Kidney - drug effects; Kidney - metabolism; Kidney - pathology; Kidney - secretion; Male; Phosphopyruvate Hydratase - chemistry; Phosphopyruvate Hydratase - genetics; Phosphopyruvate Hydratase - metabolism; Phosphopyruvate Hydratase - urine; Proteomics - methods; Rats, Sprague-Dawley; Renal Insufficiency - etiology; Spectrometry, Mass, Electrospray Ionization; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Up-Regulation - drug effects
• ISSN: 1096-6080; 1096-0929
• DOI: 10.1093/toxsci/kfv172

Cadmium (Cd(2+)) is a major environmental pollutant that induces cytotoxicity by heavy-metal accumulation. Prolonged Cd(2+) exposure leads to cell damage by oxidative stress mainly in the kidneys, a critical organ for detoxification. To identify reliable on invasive protein biomarkers for Cd(2+)-induced nephrotoxicity, we performed 2-dimensional gel electrophoresis/matrix-assisted laser desorption/ionization time of flight mass spectra and stable isotope labeling by amino acids in cell culture/liquid chromatography-mass spectrometry analyses using conditioned media (CM) of HK-2 human kidney epithelial cells treated with CdCl2. Here, we identified heat shock cognate 71 kDa protein isoform1 (HSPA8) and α-enolase (ENO1) as potential biomarker candidates for the evaluation of Cd(2+)-induced nephrotoxicity. Treatment with CdCl2 increased the protein level of HSPA8 in CM and lysates of HK-2 cells. The mRNA level of HSPA8 was also increased by CdCl2 treatment, indicating transcriptional regulation. The level of ENO1 was increased in CM, but not in lysates of CdCl2-treated HK-2 cells. CdCl2 did not affect the mRNA level of ENO1. We provide evidence that the increases of HSPA8 and ENO1 in CM were due to Cd(2+)-induced cell death through oxidative stress. The increases of HSPA8 and ENO1 levels were also detected in CM of HK-2 cells treated with other nephrotoxic agents, such as HgCl2, NaAsO2, cisplatin, amphotericin B, and cyclosporine A. Urine and kidney tissues of CdCl2-treated rats showed increased levels of HSPA8. Taken together, this study identified HSPA8 and ENO1 as noninvasive biomarker candidates by 2 comparative proteomic analyses. These new biomarker candidates may have potential as alternatives to traditional biomarkers for the efficient and sensitive assessment of nephrotoxicity.