Abstract LB-438: Proteomic analysis of aristolochic acid-induced nephrotoxicity in rats

Abstract

Abstract Aristolochic acids (AA) are a family of structurally related nitrophenanthrene carboxylic acids, mainly consisting of aristolochic acid I (AAI) and aristolochic acid II (AAII), and are the active component of some herbal medicines. Use of dietary supplements and other botanical products containing AA have resulted in severe nephrotoxicity and consequent renal replacement therapy. Aristolochic acids are potent carcinogens as well, inducing urothelial cancers in humans and kidney tumors in rats. Previous studies have shown that the tumorigenicity of AA could result from AA-induced DNA adduct formation and mutation induction. To further understand the molecular mechanisms underlying AA-induced nephrotoxicity (e.g., carcinogenesis) and identify disease biomarkers, a quantitative proteomic analysis was conducted on kidneys from AA-treated rats. Animal treatment was conducted according to the approved protocol and followed the recommendations of the NCTR Institutional Animal Care and Use Committee. Six-week-old Big Blue rats were treated with AA as its sodium salt at concentrations of 0.1, 1.0, and 10.0 mg/kg body weight by gavage five times/week for 12 weeks or with 0.9% sodium chloride as the control using the same schedule. Six rats from each treatment group were sacrificed 1 day after the last treatment. The kidneys were isolated, frozen quickly in liquid nitrogen, and stored at −80 °C. Kidney tissues from the control and the highest AA dose treatment (10 mg/kg body weight) were selected for proteomic analysis. Proteins were extracted and digested into peptides. Trypsin-catalyzed 16O/18O stable isotope labeling was performed for each pair of control/treatment samples, which were then analyzed using two-dimensional liquid chromatography coupled online with tandem mass spectrometry (LC-MS/MS). Approximately 3000 proteins were quantified from each pair of samples, and more than 150 proteins were concordantly over expressed or under expressed across all the AA-treated samples. Pathway analysis indicated that significant changes include proteins involving xenobiotic metabolism, response to stimulus including DNA damage, cell proliferation and neoplasm, etc. Intriguingly, proteins indicating kidney pathological changes such as nephron degeneration were identified as well. Although further verification is needed, the quantitative proteomic study identified proteins related to potential toxicity and oncogenic pathways and proteins that could serve as urinary biomarkers of renal damage inflicted by aristolochic acid exposure. The views presented do not necessarily reflect those of the U. S. Food and Drug Administration. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-438. doi:10.1158/1538-7445.AM2011-LB-438