The renal phenotype of allopurinol-treated HPRT-deficient mouse.

Excess of uric acid is mainly treated with xanthine oxidase (XO) inhibitors, also called uricostatics because they block the conversion of hypoxanthine and xanthine into urate. Normally, accumulation of upstream metabolites is prevented by the hypoxanthine-guanine phosphoribosyltransferase (HPRT) en...

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Main Authors: Cristina Zennaro, Federica Tonon, Paola Zarattini, Milan Clai, Alessandro Corbelli, Michele Carraro, Marialaura Marchetti, Luca Ronda, Gianluca Paredi, Maria Pia Rastaldi, Riccardo Percudani
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-01-01
Series:PLoS ONE
Online Access:https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0173512&type=printable
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author Cristina Zennaro
Federica Tonon
Paola Zarattini
Milan Clai
Alessandro Corbelli
Michele Carraro
Marialaura Marchetti
Luca Ronda
Gianluca Paredi
Maria Pia Rastaldi
Riccardo Percudani
author_facet Cristina Zennaro
Federica Tonon
Paola Zarattini
Milan Clai
Alessandro Corbelli
Michele Carraro
Marialaura Marchetti
Luca Ronda
Gianluca Paredi
Maria Pia Rastaldi
Riccardo Percudani
author_sort Cristina Zennaro
collection DOAJ
description Excess of uric acid is mainly treated with xanthine oxidase (XO) inhibitors, also called uricostatics because they block the conversion of hypoxanthine and xanthine into urate. Normally, accumulation of upstream metabolites is prevented by the hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme. The recycling pathway, however, is impaired in the presence of HPRT deficiency, as observed in Lesch-Nyhan disease. To gain insights into the consequences of purine accumulation with HPRT deficiency, we investigated the effects of the XO inhibitor allopurinol in Hprt-lacking (HPRT-/-) mice. Allopurinol was administered in the drinking water of E12-E14 pregnant mothers at dosages of 150 or 75 μg/ml, and mice sacrificed after weaning. The drug was well tolerated by wild-type animals and heterozygous HPRT+/- mice. Instead, a profound alteration of the renal function was observed in the HPRT-/- model. Increased hypoxanthine and xanthine concentrations were found in the blood. The kidneys showed a yellowish appearance, diffuse interstitial nephritis, with dilated tubules, inflammatory and fibrotic changes of the interstitium. There were numerous xanthine tubular crystals, as determined by HPLC analysis. Oil red O staining demonstrated lipid accumulation in the same location of xanthine deposits. mRNA analysis showed increased expression of adipogenesis-related molecules as well as profibrotic and proinflammatory pathways. Immunostaining showed numerous monocyte-macrophages and overexpression of alpha-smooth muscle actin in the tubulointerstitium. In vitro, addition of xanthine to tubular cells caused diffuse oil red O positivity and modification of the cell phenotype, with loss of epithelial features and appearance of mesenchymal characteristics, similarly to what was observed in vivo. Our results indicate that in the absence of HPRT, blockade of XO by allopurinol causes rapidly developing renal failure due to xanthine deposition within the mouse kidney. Xanthine seems to be directly involved in promoting lipid accumulation and subsequent phenotype changes of tubular cells, with activation of inflammation and fibrosis.
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spelling doaj-art-9fd0af6c169e46bba01855f54aef6f692025-08-20T03:26:05ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01123e017351210.1371/journal.pone.0173512The renal phenotype of allopurinol-treated HPRT-deficient mouse.Cristina ZennaroFederica TononPaola ZarattiniMilan ClaiAlessandro CorbelliMichele CarraroMarialaura MarchettiLuca RondaGianluca ParediMaria Pia RastaldiRiccardo PercudaniExcess of uric acid is mainly treated with xanthine oxidase (XO) inhibitors, also called uricostatics because they block the conversion of hypoxanthine and xanthine into urate. Normally, accumulation of upstream metabolites is prevented by the hypoxanthine-guanine phosphoribosyltransferase (HPRT) enzyme. The recycling pathway, however, is impaired in the presence of HPRT deficiency, as observed in Lesch-Nyhan disease. To gain insights into the consequences of purine accumulation with HPRT deficiency, we investigated the effects of the XO inhibitor allopurinol in Hprt-lacking (HPRT-/-) mice. Allopurinol was administered in the drinking water of E12-E14 pregnant mothers at dosages of 150 or 75 μg/ml, and mice sacrificed after weaning. The drug was well tolerated by wild-type animals and heterozygous HPRT+/- mice. Instead, a profound alteration of the renal function was observed in the HPRT-/- model. Increased hypoxanthine and xanthine concentrations were found in the blood. The kidneys showed a yellowish appearance, diffuse interstitial nephritis, with dilated tubules, inflammatory and fibrotic changes of the interstitium. There were numerous xanthine tubular crystals, as determined by HPLC analysis. Oil red O staining demonstrated lipid accumulation in the same location of xanthine deposits. mRNA analysis showed increased expression of adipogenesis-related molecules as well as profibrotic and proinflammatory pathways. Immunostaining showed numerous monocyte-macrophages and overexpression of alpha-smooth muscle actin in the tubulointerstitium. In vitro, addition of xanthine to tubular cells caused diffuse oil red O positivity and modification of the cell phenotype, with loss of epithelial features and appearance of mesenchymal characteristics, similarly to what was observed in vivo. Our results indicate that in the absence of HPRT, blockade of XO by allopurinol causes rapidly developing renal failure due to xanthine deposition within the mouse kidney. Xanthine seems to be directly involved in promoting lipid accumulation and subsequent phenotype changes of tubular cells, with activation of inflammation and fibrosis.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0173512&type=printable
spellingShingle Cristina Zennaro
Federica Tonon
Paola Zarattini
Milan Clai
Alessandro Corbelli
Michele Carraro
Marialaura Marchetti
Luca Ronda
Gianluca Paredi
Maria Pia Rastaldi
Riccardo Percudani
The renal phenotype of allopurinol-treated HPRT-deficient mouse.
PLoS ONE
title The renal phenotype of allopurinol-treated HPRT-deficient mouse.
title_full The renal phenotype of allopurinol-treated HPRT-deficient mouse.
title_fullStr The renal phenotype of allopurinol-treated HPRT-deficient mouse.
title_full_unstemmed The renal phenotype of allopurinol-treated HPRT-deficient mouse.
title_short The renal phenotype of allopurinol-treated HPRT-deficient mouse.
title_sort renal phenotype of allopurinol treated hprt deficient mouse
url https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0173512&type=printable
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