Apoptosis induced by an uromodulin mutant C112Y and its suppression by topiroxostat

Utami, Sulistiyati Bayu; Mahati, Endang; Li, Peili; Maharani, Nani; Ikeda, Naho; Bahrudin, Udin; Munemura, Chishio; Hosoyamada, Makoto; Yamamoto, Yorihiro; Yoshïda, Akio; Nakayama, Yuji; Higaki, Kazutaka; Nanba, Eiji; Ninomiya, Haruaki; Shirayoshi, Yasuaki; Ichida, Kimiyoshi; Yamamoto, Kazuhide; Hosoya, Tatsuo; Hisatome, Ichiro

doi:10.1007/s10157-014-1032-8

Cited by 14 publications

(9 citation statements)

References 23 publications

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“…Activation of this stress response greatly impacts on cell fate and function and can promote cell survival or cell death [31]. Our experiments did not show induction of apoptosis, in contrast with previous studies in other cellular models of mutant uromodulin expression [41,47]. However, lack of apoptosis in cells expressing mutant uromodulin is consistent with our previous findings in an in vivo model of ADTKD- UMOD [19].…”

Section: Discussionsupporting

confidence: 90%

“…As previously described [24,25], mutant uromodulin isoforms are largely retained in the ER, likely due to protein misfolding. By metabolic labelling we show that the ER retained protein is degraded via the proteasome pathway, as observed for the C112Y uromodulin mutant [41]. We also demonstrate for the first time that mutant uromodulin shows increased interaction with several ER chaperones, namely calnexin, PDI and BiP, suggesting that uromodulin enters the calnexin cycle to be properly folded [42].…”

Section: Discussionmentioning

confidence: 70%

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Mutant uromodulin expression leads to altered homeostasis of the endoplasmic reticulum and activates the unfolded protein response

et al. 2017

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Uromodulin is the most abundant urinary protein in physiological conditions. It is exclusively produced by renal epithelial cells lining the thick ascending limb of Henle’s loop (TAL) and it plays key roles in kidney function and disease. Mutations in UMOD, the gene encoding uromodulin, cause autosomal dominant tubulointerstitial kidney disease uromodulin-related (ADTKD-UMOD), characterised by hyperuricemia, gout and progressive loss of renal function. While the primary effect of UMOD mutations, retention in the endoplasmic reticulum (ER), is well established, its downstream effects are still largely unknown. To gain insight into ADTKD-UMOD pathogenesis, we performed transcriptional profiling and biochemical characterisation of cellular models (immortalised mouse TAL cells) of robust expression of wild type or mutant GFP-tagged uromodulin. In this model mutant uromodulin accumulation in the ER does not impact on cell viability and proliferation. Transcriptional profiling identified 109 genes that are differentially expressed in mutant cells relative to wild type ones. Up-regulated genes include several ER resident chaperones and protein disulphide isomerases. Consistently, pathway enrichment analysis indicates that mutant uromodulin expression affects ER function and protein homeostasis. Interestingly, mutant uromodulin expression induces the Unfolded Protein Response (UPR), and specifically the IRE1 branch, as shown by an increased splicing of XBP1. Consistent with UPR induction, we show increased interaction of mutant uromodulin with ER chaperones Bip, calnexin and PDI. Using metabolic labelling, we also demonstrate that while autophagy plays no role, mutant protein is partially degraded by the proteasome through ER-associated degradation. Our work demonstrates that ER stress could play a central role in ADTKD-UMOD pathogenesis. This sets the bases for future work to develop novel therapeutic strategies through modulation of ER homeostasis and associated protein degradation pathways.

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Section: Discussionsupporting

confidence: 90%

Section: Discussionmentioning

confidence: 70%

Mutant uromodulin expression leads to altered homeostasis of the endoplasmic reticulum and activates the unfolded protein response

et al. 2017

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“…Second, XOR inhibitors showed a significant improvement of GFR . Third, topiroxostat showed the protective effect on familial juvenile hyperuricemic nephropathy model and showed urinary albumin reduction in patients with stage 3 chronic kidney disease …”

Section: Resultsmentioning

confidence: 96%

“…6,25 Third, topiroxostat showed the protective effect on familial juvenile hyperuricemic nephropathy model and showed urinary albumin reduction in patients with stage 3 chronic kidney disease. 19,26 Limitations of the study Some limitations of this study warrant mention. First, the study period was short, which may limit the estimation of the serum urate-lowering efficacy and the safety of topiroxostat.…”

Section: Safetymentioning

confidence: 96%

Clinical efficacy and safety of topiroxostat in Japanese male hyperuricemic patients with or without gout: an exploratory, phase 2a, multicentre, randomized, double‐blind, placebo‐controlled study

Hosoya

Sasaki²,

Hashimoto

et al. 2016

J Clin Pharm Ther

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SUMMARYWhat is known and objective: In Japan, although topiroxostat, a selective xanthine oxidoreductase inhibitor, has been used for the treatment of patients with hyperuricemia including gout, no published randomized controlled studies evaluating the dosedependent relationship with respect to the serum urate-lowering efficacy have been reported. The aim of this study was to evaluate the dose-dependent relationship with serum uratelowering efficacy and safety of topiroxostat in Japanese hyperuricemic patients including gout. Methods: We conducted an exploratory, phase 2a, multicentre, randomized, double-blind, 8-week, placebo-controlled study in Japanese hyperuricemic patients with or without gout. The study arms were placebo and topiroxostat 40, 60, 80 or 120 mg/day. The primary efficacy endpoint was the per cent change in serum urate level from baseline to the final visit. Results and discussion: One hundred and eighty-seven eligible patients were randomized and 186 received at least one dose of the study drug. The study results demonstrated a dosedependent serum urate reduction effect ranging from 40 to 120 mg/day (P < 0Á001, Jonckheere-Terpstra test). The mean per cent change in serum urate level from baseline at the final visit was À30Á8% in the 120-mg group and 1Á6% with placebo, with a between-group difference of À32Á4% ([95% confidence interval, À38Á9% to À25Á9%]; P < 0Á001). Incidences of overall adverse events (AEs) in the topiroxostat groups were comparable to those in the placebo group; however, the incidence of AEs in the 120-mg group was statistically lower than that in the placebo group. The incidences of gouty arthritis were not statistically but numerically higher in the topiroxostat 80-and 120-mg groups. What is new and conclusions: A dose-dependent serum uratelowering efficacy of topiroxostat was observed in Japanese hyperuricemic male patients with or without gout. Further clinical studies aimed at evaluating the long-term safety and clinical efficacy are warranted. WHAT IS KNOWN AND OBJECTIVEHyperuricemia (defined as the serum urate level >416Á4 lmol/L [or 7Á0 mg/dL] in Japan) is a causative factor of urate deposition diseases (e.g. urolithiasis and gouty arthritis). From the standpoint of preventing gout, the primary goal of treating hyperuricemia is to reduce the serum urate level and maintain it at ≤356Á9 lmol/L (or 6Á0 mg/dL), and at this level, urate crystal deposition is reversed.

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“…Our results showed that the expression levels of genes encoding caspase-1 and caspase-6 gradually declined following pIC challenge, presenting a significant down-regulation at 24 hpi. Mutations in uromodulin (UMOD), a protein abundant in mammalian urine, can induce cellular apoptosis [ 53 ], and a gene encoding this protein was identified among the top 15 most down-regulated genes. FAS-associated death domain protein (FADD), an adaptor protein for members of the tumor necrosis factor receptor superfamily (TNFRSF), induces apoptosis in mammalian cells after transfection in vitro [ 54 ].…”

Section: Discussionmentioning

confidence: 99%

Genome-wide gene expression analysis in the amphioxus,Branchiostoma belcheriafter poly (I: C) challenge using strand-specific RNA-seq

et al. 2017

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The gene expression associated with immune response to bacteria/bacterial mimic has been extensively analyzed in amphioxus, but remains largely unknown about how gene are involved in the immune response to viral invasion at expression level. Here, we analyze the rRNA-depleted transcriptomes of Branchiostoma belcheri using strand-specific RNA-seq in response to the viral mimic, poly (I:C) (pIC). A total of 5,317 differentially expressed genes were detected at treatment group by comparing with control. The gene with the most significant expression changes (top 15) after pIC challenge and 7 immune-related categories involving 58 differently expressed genes were scrutinized. By functional enrichment analysis of differently expressed genes, gene ontology terms involving response to stress and stimulus, apoptosis, catabolic and metabolic processes and enzyme activity were overrepresented, and several pathways related to immune signaling, immune response, cancer, apoptosis, viral disease, metabolism were activated after pIC injection. A positive correlation between the qRT-PCR and strand-specific RNA-seq data confirmed the accuracy of the RNA-seq results. Additionally, the expression of genes encoding NLRC5, CASP1, CASP6, CYP450, CAT, and MDA5 were induced in B. belcheri under pIC challenge. Our experiments provide insight into the immune response of amphioxus to pIC and valuable gene expression information for studying the evolution of antiviral immunity in vertebrates.

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Apoptosis induced by an uromodulin mutant C112Y and its suppression by topiroxostat

Abstract: C112Y causes its protein instability resulting cellular apoptosis which could be suppressed with topiroxostat.

Cited by 14 publications

References 23 publications

Mutant uromodulin expression leads to altered homeostasis of the endoplasmic reticulum and activates the unfolded protein response

Mutant uromodulin expression leads to altered homeostasis of the endoplasmic reticulum and activates the unfolded protein response

Clinical efficacy and safety of topiroxostat in Japanese male hyperuricemic patients with or without gout: an exploratory, phase 2a, multicentre, randomized, double‐blind, placebo‐controlled study

Genome-wide gene expression analysis in the amphioxus,Branchiostoma belcheriafter poly (I: C) challenge using strand-specific RNA-seq

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