title: Proteins identified as targets of the acyl glucuronide metabolite of mycophenolic acid in kidney tissue from mycophenolate mofetil treated rats.
abstract: Covalent binding of the acyl glucuronide (AcMPAG) metabolite of the immunosuppressant mycophenolic acid (MPA) to proteins is considered a possible initiating event for organ toxicity. Since the kidney is involved in the formation and excretion of AcMPAG, it can be hypothesized that this tissue may be exposed to relatively high concentrations of this metabolite and would, therefore, be a particularly suitable organ to investigate AcMPAG protein targets. In the present study we identified potential AcMPAG target proteins in kidney tissues from Wistar rats treated with mycophenolate mofetil (40 mg/kg/day over 21 days). Proteins were separated by 2-DE and covalent protein adducts were detected by Western blotting with an antibody specific for MPA/AcMPAG. The corresponding coomassie blue stained proteins from parallel gels were subjected to in-gel tryptic digestion and peptides were characterized on a Q-TOF Ultima Global. The protein targets were further verified by immunoprecipitation with anti-MPA/AcMPAG antibody to purify the modified proteins followed by 1-DE and MS analysis. Database searches revealed several AcMPAG target proteins that could be related to ultrastructural abnormalities, metabolic effects, and altered oxidative stress/detoxification responses. Predominately cytosolic proteins such as selenium binding protein, protein disulfide isomerase, aldehyde dehydrogenase, triosephosphate isomerase, and kidney aminoacylase were involved in adduct formation. Two cytoskeletal proteins tropomyosin 1 and 4 as well as the antioxidant proteins peroxiredoxin 3 and 6 were also targets of AcMPAG. Functional consequences from these protein modifications remain to be demonstrated.
authors.affiliation: Abteilung Klinische Chemie, Georg-August-Universität, Robert-Koch-Strasse 40, D-37075 Göttingen, Germany. asif@med.uni-goettingen.de
authors.forename: Abdul R
authors.initials: AR
authors.lastname: Asif
authors.forename: Victor W
authors.initials: VW
authors.lastname: Armstrong
authors.forename: Antje
authors.initials: A
authors.lastname: Voland
authors.forename: Eberhard
authors.initials: E
authors.lastname: Wieland
authors.forename: Michael
authors.initials: M
authors.lastname: Oellerich
authors.forename: Maria
authors.initials: M
authors.lastname: Shipkova
mesh_terms: D000818:Animals; D015153:Blotting, Western; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D020719:Glucuronides / Q000378:metabolism*; D015151:Immunoblotting; D047468:Immunoprecipitation; D007166:Immunosuppressive Agents / Q000378:metabolism / Q000494:pharmacology; D007668:Kidney / Q000187:drug effects / Q000378:metabolism*; D013058:Mass Spectrometry; D009173:Mycophenolic Acid / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D011506:Proteins / Q000032:analysis* / Q000302:isolation & purification; D040901:Proteomics / Q000379:methods; D051381:Rats; D017208:Rats, Wistar
chemical_list: D020719:Glucuronides; D007166:Immunosuppressive Agents; D011506:Proteins; D009173:Mycophenolic Acid