BACKGROUND: Familial juvenile hyperuricemic nephropathy (FJHN) is an autosomal dominant disorder caused by mutations in UMOD that encodes uromodulin. Topiroxostat, a novel non-purine analog, selectively inhibits xanthine oxidase and reduces the serum uric acid levels and the urinary albuminuria. METHODS: Genomic DNA of a patient was extracted from peripheral white blood. Exons and flanking sequences of UMOD were amplified by PCR with primers. Mutation analysis was performed by direct sequencing of the PCR products. The wild-type and mutant uromodulin were expressed in HEK293 cells and analyzed by western blotting, immunoprecipitation, immunofluorescence, and flow cytometry. RESULTS: We identified an FJHN patient who carried a novel UMOD mutation G335A (C112Y). The levels of both cytosolic and secreted C112Y protein were significantly decreased compared with the wild-type, whereas the level of ubiquitination was higher in C112Y than that in the wild type. The half-life of C112Y was shortened and it was restored by a proteasome inhibitor MG132. Immunofluorescence revealed decreased levels of C112Y in the Golgi apparatus and on the plasma membrane. Expression of C112Y induced cellular apoptosis as revealed by flow cytometry. Apoptosis induced by C112Y was suppressed by topiroxostat. CONCLUSION: C112Y causes its protein instability resulting cellular apoptosis which could be suppressed with topiroxostat.
BACKGROUND:Familial juvenile hyperuricemic nephropathy (FJHN) is an autosomal dominant disorder caused by mutations in UMOD that encodes uromodulin. Topiroxostat, a novel non-purine analog, selectively inhibits xanthine oxidase and reduces the serum uric acid levels and the urinary albuminuria. METHODS: Genomic DNA of a patient was extracted from peripheral white blood. Exons and flanking sequences of UMOD were amplified by PCR with primers. Mutation analysis was performed by direct sequencing of the PCR products. The wild-type and mutant uromodulin were expressed in HEK293 cells and analyzed by western blotting, immunoprecipitation, immunofluorescence, and flow cytometry. RESULTS: We identified an FJHNpatient who carried a novel UMOD mutation G335A (C112Y). The levels of both cytosolic and secreted C112Y protein were significantly decreased compared with the wild-type, whereas the level of ubiquitination was higher in C112Y than that in the wild type. The half-life of C112Y was shortened and it was restored by a proteasome inhibitor MG132. Immunofluorescence revealed decreased levels of C112Y in the Golgi apparatus and on the plasma membrane. Expression of C112Y induced cellular apoptosis as revealed by flow cytometry. Apoptosis induced by C112Y was suppressed by topiroxostat. CONCLUSION:C112Y causes its protein instability resulting cellular apoptosis which could be suppressed with topiroxostat.
Authors: J J O Turner; J M Stacey; B Harding; P Kotanko; K Lhotta; J G Puig; I Roberts; R J Torres; R V Thakker Journal: J Clin Endocrinol Metab Date: 2003-03 Impact factor: 5.958
Authors: Marcus D Säemann; Thomas Weichhart; Maximilian Zeyda; Günther Staffler; Michael Schunn; Karl M Stuhlmeier; Yuri Sobanov; Thomas M Stulnig; Shizuo Akira; Alexander von Gabain; Uwe von Ahsen; Walter H Hörl; Gerhard J Zlabinger Journal: J Clin Invest Date: 2005-02 Impact factor: 14.808
Authors: Sung Won Choi; Ok Hee Ryu; Sun Jin Choi; In Sun Song; Anthony J Bleyer; Thomas C Hart Journal: J Am Soc Nephrol Date: 2005-08-31 Impact factor: 10.121
Authors: P Vylet'al; M Kublová; M Kalbácová; K Hodanová; V Baresová; B Stibůrková; J Sikora; H Hůlková; J Zivný; J Majewski; A Simmonds; J-P Fryns; G Venkat-Raman; M Elleder; S Kmoch Journal: Kidney Int Date: 2006-08-02 Impact factor: 10.612
Authors: Siân E Williams; Anita A C Reed; Juris Galvanovskis; Corinne Antignac; Tim Goodship; Fiona E Karet; Peter Kotanko; Karl Lhotta; Vincent Morinière; Paul Williams; William Wong; Patrik Rorsman; Rajesh V Thakker Journal: Hum Mol Genet Date: 2009-05-22 Impact factor: 6.150