Toxicol Sci 2003 Mar 25; [epub ahead of print]
A Correlation between a Proteomic Evaluation and Conventional Measurements in the Assessment of Renal Proximal Tubular Toxicity.
Bandara LR, Kelly MD, Lock EA, Kennedy S.
Oxford GlycoSciences (UK) Ltd, The Forum, 86 Milton Park, Abingdon, Oxon OX14 4RY, U.K.
4-aminophenol (4-AP), D-serine and cisplatin are established rodent nephrotoxins that damage proximal tubules within the renal cortex. Using high throughput 2D gel proteomics to profile protein changes in the plasma of compound treated animals, we identified several markers of kidney toxicity. Male F344 and Alpk rats were treated with increasing doses of 4-AP, D-serine or cisplatin and plasma samples were collected over time. Control groups received saline or non-toxic isomers, L-serine and transplatin. Plasma proteins that displayed dose and temporal dependent regulation in each study were further characterised by mass spectrometry to elucidate the protein identity. Several isoforms of the rat specific T-kininogen protein were identified in each study. T-kininogen was elevated in the plasma of 4-AP, D-serine, and cisplatin treated animals at early time points returning to base line levels 3 weeks after treatment. The protein was not elevated in the plasma of control animals or those treated with, non-toxic compounds. We propose that T-kininogen may be required to counteract apoptosis in proximal tubular cells in order to minimise tissue damage following a toxic insult. In addition, T-kininogen may be required to stimulate localised inflammation to aid tissue repair. We also identified several isoforms of the inter-alpha-inhibitor H4P heavy chain in 4-AP and D-serine studies. In each case the protein expression levels in the blood samples paralleled the extent of kidney toxicity highlighting the correlation between protein alterations and clinical chemistry endpoints. A further set of proteins correlating with kidney damage were found to be components of the complement cascade and other blood clotting factors indicating a contribution of the immune system to the observed toxicity. These observations underscore the value of proteomics in identifying new biomarkers and in the elucidation of mechanisms of toxicity. |
