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Experimental Diabetes Research
Volume 2011, Article ID 278963, 11 pages
http://dx.doi.org/10.1155/2011/278963
Research Article

Osmolarity and Glucose Differentially Regulate Aldose Reductase Activity in Cultured Mouse Podocytes

1Department of Pathophysiology, Medical University of Gdansk, 80-211 Gdansk, Poland
2Laboratory of Cellular and Molecular Nephrology, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw/Gdansk, Poland
3Department of Clinical Immunology and Transplantation, Medical University of Gdansk, 80-210 Gdansk, Poland

Received 14 July 2011; Revised 5 September 2011; Accepted 23 September 2011

Academic Editor: Theodore W. Kurtz

Copyright © 2011 Barbara Lewko et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Podocyte injury is associated with progression of many renal diseases, including diabetic nephropathy. In this study we examined whether aldose reductase (AR), the enzyme implicated in diabetic complications in different tissues, is modulated by high glucose and osmolarity in podocyte cells. AR mRNA, protein expression, and activity were measured in mouse podocytes cultured in both normal and high glucose and osmolarity for 6 hours to 5 days. Hyperosmolarity acutely stimulated AR expression and activity, with subsequent increase of AR expression but decrease of activity. High glucose also elevated AR protein level; however, this was not accompanied by respective enzyme activation. Furthermore, high glucose appeared to counteract the osmolarity-dependent activation of AR. In conclusion, in podocytes AR is modulated by high glucose and increased osmolarity in a different manner. Posttranslational events may affect AR activity independent of enzyme protein amount. Activation of AR in podocytes may be implicated in diabetic podocytopathy.