Noncrystalline uric acid inhibits proteoglycan and glycosaminoglycan synthesis in distal tubular epithelial cells (MDCK)

Noncrystalline uric acid inhibits proteoglycan and glycosaminoglycan synthesis in distal tubular epithelial cells (MDCK)

Autor Borges, Fernanda Teixeira Autor UNIFESP Google Scholar
Dalboni, Maria Aparecida Autor UNIFESP Google Scholar
Michelacci, Yara Maria Autor UNIFESP Google Scholar
Schor, Nestor Autor UNIFESP Google Scholar
Instituição Universidade Federal de São Paulo (UNIFESP)
Resumo Hyperuricemia is associated with renal stones, not only consisting of uric acid (UrAc) but also of calcium oxalate (CaOx). Glycosaminoglycans (GAGs) are well-known inhibitors of growth and aggregation of CaOx crystals. We analyzed the effect of noncrystalline UrAc on GAG synthesis in tubular distal cells. MDCK (Madin-Darby canine kidney) cells were exposed to noncrystalline UrAc (80 µg/mL) for 24 h. GAGs were labeled metabolically and characterized by agarose gel electrophoresis. The expression of proteoglycans and cyclooxygenase 2 (COX-2) was assessed by real-time PCR. Necrosis, apoptosis and prostaglandin E2 (PGE2) were determined by acridine orange, HOESCHT 33346, and ELISA, respectively. CaOx crystal endocytosis was evaluated by flow cytometry. Noncrystalline UrAc significantly decreased the synthesis and secretion of heparan sulfate into the culture medium (UrAc: 2127 ± 377; control: 4447 ± 730 cpm) and decreased the expression of perlecan core protein (UrAc: 0.61 ± 0.13; control: 1.07 ± 0.16 arbitrary units), but not versican. Noncrystalline UrAc did not induce necrosis or apoptosis, but significantly increased COX-2 and PGE2 production. The effects of noncrystalline UrAc on GAG synthesis could not be attributed to inflammatory actions because lipopolysaccharide, as the positive control, did not have the same effect. CaOx was significantly endocytosed by MDCK cells, but this endocytosis was inhibited by exposure to noncrystalline UrAc (control: 674.6 ± 4.6, CaOx: 724.2 ± 4.2, and UrAc + CaOx: 688.6 ± 5.4 geometric mean), perhaps allowing interaction with CaOx crystals. Our results indicate that UrAc decreases GAG synthesis in MDCK cells and this effect could be related to the formation of UrAc and CaOx stones.
Palavra-chave Noncrystalline uric acid
Glycosaminoglycan
MDCK
Lipopolysaccharide
Apoptosis
Proteoglycan
Idioma Inglês
Financiador Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
FINEP
Fundacao Oswaldo Ramos (FOR)
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Data de publicação 2010-10-01
Publicado em Brazilian Journal of Medical and Biological Research. Associação Brasileira de Divulgação Científica, v. 43, n. 10, p. 957-963, 2010.
ISSN 0100-879X (Sherpa/Romeo, fator de impacto)
Publicador Associação Brasileira de Divulgação Científica
Extensão 957-963
Fonte http://dx.doi.org/10.1590/S0100-879X2010007500095
Direito de acesso Acesso aberto Open Access
Tipo Artigo
Web of Science WOS:000283263500006
SciELO S0100-879X2010001000006 (estatísticas na SciELO)
Endereço permanente http://repositorio.unifesp.br/handle/11600/5951

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