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Hureaux M, Vargas-Poussou R. Genetic basis of nephrogenic diabetes insipidus. Mol Cell Endocrinol 2023; 560:111825. [PMID: 36460218 DOI: 10.1016/j.mce.2022.111825] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Revised: 10/26/2022] [Accepted: 10/28/2022] [Indexed: 12/02/2022]
Abstract
Nephrogenic diabetes insipidus is defined as an inability to concentrate urine due to a complete or partial alteration of the renal tubular response to arginine vasopressin hormone, resulting in excessive diluted urine excretion. Hereditary forms are caused by molecular defects in the genes encoding either of the two main renal effectors of the arginine vasopressin pathway: the AVPR2 gene, which encodes for the type 2 vasopressin receptor, or the AQP2 gene, which encodes for the water channel aquaporin-2. About 90% of cases of nephrogenic diabetes insipidus result from loss-of-function variants in the AVPR2 gene, which are inherited in a X-linked recessive manner. The remaining 10% of cases result from loss-of-function variants in the AQP2 gene, which can be inherited in either a recessive or a dominant manner. The main symptoms of the disease are polyuria, chronic dehydration and hypernatremia. These symptoms usually occur in the first year of life, although some patients present later. Diagnosis is based on abnormal response in urinary osmolality after water restriction and/or administration of exogenous vasopressin. Treatment involves ensuring adequate water intake on demand, possibly combined with thiazide diuretics, non-steroidal anti-inflammatory drugs, and a low-salt and protein diet. In this review, we provide an update on current understanding of the molecular basis of inherited nephrogenic insipidus diabetes.
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Affiliation(s)
- Marguerite Hureaux
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Department of Genetics, France and University of Paris Cité, Paris, France; Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France
| | - Rosa Vargas-Poussou
- Assistance Publique Hôpitaux de Paris, Hôpital Européen Georges-Pompidou, Department of Genetics, France and University of Paris Cité, Paris, France; Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte (MARHEA), Paris, France.
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2
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Sollid JE, Joshi S, Pulczynska Wason M, Rittig S, Hvarregaard Christensen J, Kamperis K. Novel Variant of AVPR2 Giving Rise to X-Linked Congenital Nephrogenic Diabetes Insipidus in a 7-Month-Old Danish Boy. Case Rep Nephrol Dial 2020; 10:124-129. [PMID: 33251249 PMCID: PMC7670377 DOI: 10.1159/000508786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 05/17/2020] [Indexed: 11/19/2022] Open
Abstract
Patients affected with congenital nephrogenic diabetes insipidus (CNDI) have reduced ability to concentrate urine. Early diagnosis of CNDI is important to avoid recurrent episodes of severe dehydration. We present a Danish male suffering from typical symptoms and diagnosed with CNDI at the age of 7 months. Gene sequencing of this proband and his mother revealed a novel variant in the gene encoding the antidiuretic hormone receptor (AVPR2). The variant is a deletion of nucleotide c.151 in exon 2 of AVPR2 (GenBank NM_000054.4:c.151del). This 1bp deletion is predicted to cause a frameshift that results in tryptophan replacing valine at position 51 in AVPR2 and a premature stop codon three codons downstream (p.Val51Trpfs*3) likely resulting in faulty expression of the receptor. Identification of disease-causing variants such as the one described here contributes to precise diagnosis, especially in carriers and newborns, thus preventing the long-term physical and intellectual disability observed in some CNDI-patients.
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Affiliation(s)
| | - Shivani Joshi
- Child and Youth Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | | | - Søren Rittig
- Child and Youth Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Konstantinos Kamperis
- Child and Youth Research Laboratory, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.,Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
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3
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Makita N, Manaka K, Sato J, Iiri T. V2 vasopressin receptor mutations. VITAMINS AND HORMONES 2019; 113:79-99. [PMID: 32138955 DOI: 10.1016/bs.vh.2019.08.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
V2 vasopressin receptor (V2R) is a member of the G protein-coupled receptor (GPCR) family in which many disease-causing mutations have been identified and thus generated much interest. Loss-of-function V2R mutations cause nephrogenic diabetes insipidus (NDI) whereas gain-of-function mutations cause nephrogenic syndrome of inappropriate antidiuresis (NSIAD). The mechanisms underlying a V2R loss-of-function can be theoretically classified as either protein expression, localization (ER retention) or functional disorders. Functional analyses have revealed however that these mechanisms are likely to be complex. Strikingly, V2R mutations at the same site can result in opposite phenotypes, e.g., R137H and R137L/C cause NDI and NSIAD, respectively. These findings support the notion that the constitutive activation of GPCRs might be often associated with their instability and denaturation. Thus, functional analysis of disease-causing V2R mutations may not only reveal potential new treatment strategies using pharmacochaperones for NDI and inverse agonists for NSIAD, but also provide a greater understanding of the physiological functions of GPCRs and highlight the new paradigms, i.e., biased agonism and protean agonism.
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Affiliation(s)
- Noriko Makita
- Department of Endocrinology and Nephrology, The University of Tokyo, Tokyo, Japan.
| | - Katsunori Manaka
- Department of Endocrinology and Nephrology, The University of Tokyo, Tokyo, Japan
| | - Junichiro Sato
- Department of Endocrinology and Nephrology, The University of Tokyo, Tokyo, Japan
| | - Taroh Iiri
- Department of Endocrinology and Nephrology, The University of Tokyo, Tokyo, Japan; Department of Pharmacology, St. Marianna University School of Medicine, Kawasaki, Japan.
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4
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Marinko J, Huang H, Penn WD, Capra JA, Schlebach JP, Sanders CR. Folding and Misfolding of Human Membrane Proteins in Health and Disease: From Single Molecules to Cellular Proteostasis. Chem Rev 2019; 119:5537-5606. [PMID: 30608666 PMCID: PMC6506414 DOI: 10.1021/acs.chemrev.8b00532] [Citation(s) in RCA: 162] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Indexed: 12/13/2022]
Abstract
Advances over the past 25 years have revealed much about how the structural properties of membranes and associated proteins are linked to the thermodynamics and kinetics of membrane protein (MP) folding. At the same time biochemical progress has outlined how cellular proteostasis networks mediate MP folding and manage misfolding in the cell. When combined with results from genomic sequencing, these studies have established paradigms for how MP folding and misfolding are linked to the molecular etiologies of a variety of diseases. This emerging framework has paved the way for the development of a new class of small molecule "pharmacological chaperones" that bind to and stabilize misfolded MP variants, some of which are now in clinical use. In this review, we comprehensively outline current perspectives on the folding and misfolding of integral MPs as well as the mechanisms of cellular MP quality control. Based on these perspectives, we highlight new opportunities for innovations that bridge our molecular understanding of the energetics of MP folding with the nuanced complexity of biological systems. Given the many linkages between MP misfolding and human disease, we also examine some of the exciting opportunities to leverage these advances to address emerging challenges in the development of therapeutics and precision medicine.
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Affiliation(s)
- Justin
T. Marinko
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Wesley D. Penn
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - John A. Capra
- Center
for Structural Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Department
of Biological Sciences, Vanderbilt University, Nashville, Tennessee 37245, United States
| | - Jonathan P. Schlebach
- Department
of Chemistry, Indiana University, Bloomington, Indiana 47405, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt University, Nashville, Tennessee 37240, United States
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5
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Chemical validation and optimization of pharmacoperones targeting vasopressin type 2 receptor mutant. Biochem J 2018; 475:2941-2953. [PMID: 30068530 DOI: 10.1042/bcj20180065] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 07/09/2018] [Accepted: 07/31/2018] [Indexed: 11/17/2022]
Abstract
A series of compounds formerly identified by high-throughput screening was studied for their ability to serve as pharmacoperones for the vasopressin type 2 receptor (V2R) mutant L83Q, which is known to cause nephrogenic diabetes insipidus (NDI). Three compounds were particularly effective in rerouting the mutant receptor in a concentration-dependent manner, were neither agonists nor antagonists, and displayed low cellular toxicity. Compound 1 was most effective and can be used as a molecular probe for future studies of how small molecules may affect NDI caused by mutant V2R. These compounds, however, failed to rescue the V2R Y128S mutant, indicating that the compounds described may not work in the rescue of all known mutants of V2R. Taken collectively, the present studies have now identified a promising lead compound that could function as a pharmacoperone to correct the trafficking defect of the NDI-associated mutant V2R L83Q and thus has the therapeutic potential for the treatment of NDI.
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6
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Joshi S, Kvistgaard H, Kamperis K, Færch M, Hagstrøm S, Gregersen N, Rittig S, Christensen JH. Novel and recurrent variants in AVPR2 in 19 families with X-linked congenital nephrogenic diabetes insipidus. Eur J Pediatr 2018; 177:1399-1405. [PMID: 29594432 DOI: 10.1007/s00431-018-3132-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 03/14/2018] [Accepted: 03/14/2018] [Indexed: 02/06/2023]
Abstract
UNLABELLED Congenital nephrogenic diabetes insipidus (CNDI) is characterized by the reduced ability of renal collecting duct cells to reabsorb water in response to the antidiuretic effect of vasopressin. Chronic polyuria and polydipsia are the hallmarks of the disease. Approximately 90% of all patients with CNDI have X-linked inherited disease caused by variants in the arginine vasopressin receptor 2 (AVPR2) gene. We present genetic findings in 34 individuals from 19 kindreds including one or more family members with CNDI. Coding regions of AVPR2 were sequenced bi-directionally. We identified eight novel disease-causing variants in AVPR2, p.Arg68Alafs*124, p.Ser171Arg, p.Gln174Pro, p.Trp200Arg, p.Gly201Cys, p.Gly220Arg, p.Val226Glu, and p.Gln291Pro in nine kindreds. In all three families with more than one affected individual, the novel variants segregated with the disease. We also identified eight recurrent disease-causing variants, p.Val88Met, p.Leu111Valfs*80, p.Arg113Trp, p.Tyr124*, p.Ser167Leu, p.Thr207Asn, p.Arg247Alafs*12, and p.Arg337* in ten kindreds. Our findings contribute to the growing list of AVPR2 variants causing X-linked CNDI. CONCLUSION Being a rapid diagnostic tool for CNDI, direct sequencing of AVPR2 should be encouraged in newborns with familial predisposition to CNDI. What is Known: • Disease-causing variants in AVPR2 cause X-linked congenital nephrogenic diabetes insipidus (CNDI). • DNA sequencing of AVPR2 is rapid, facilitates differential diagnosis, early intervention, and genetic diagnosis thus reducing morbidity in CNDI. What is New: • We identified eight novel disease-causing variants in AVPR2: p.Arg68Alafs*124, p.Ser171Arg, p.Gln174Pro, p.Trp200Arg, p.Gly201Cys, p.Gly220Arg, p.Val226Glu, and p.Gln291Pro, thereby adding to the growing list of AVPR2 disease-causing variants and emphasizing the importance of genetic testing in CNDI.
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Affiliation(s)
- Shivani Joshi
- Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Helene Kvistgaard
- Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Konstantinos Kamperis
- Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Mia Færch
- Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Søren Hagstrøm
- Department of Pediatrics, Aalborg University Hospital, Reberbansgade 15, 9000, Aalborg, Denmark
| | - Niels Gregersen
- Department of Clinical Medicine - Research Unit for Molecular Medicine, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Søren Rittig
- Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark
| | - Jane Hvarregaard Christensen
- Department of Pediatrics and Adolescent Medicine and Department of Clinical Medicine, Aarhus University Hospital, Palle Juul-Jensens Boulevard 99, 8200, Aarhus N, Denmark. .,Department of Biomedicine, Aarhus University, Bartholins Allé 6, 8000, Aarhus C, Denmark.
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7
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Joshi S, Brandstrom P, Gregersen N, Rittig S, Christensen JH. Novel de novo AVPR2 Variant in a Patient with Congenital Nephrogenic Diabetes Insipidus. Case Rep Nephrol Dial 2017; 7:130-137. [PMID: 29177155 PMCID: PMC5696758 DOI: 10.1159/000480009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Accepted: 07/28/2017] [Indexed: 12/26/2022] Open
Abstract
Early diagnosis and treatment of congenital nephrogenic diabetes insipidus (CNDI) are essential due to the risk of intellectual disability caused by repeated episodes of dehydration and rapid rehydration. Timely genetic testing for disease-causing variants in the arginine vasopressin receptor 2 (AVPR2) gene is possible in at-risk newborns with a known family history of X-linked CNDI. In this study, a Swedish male with no family history was diagnosed with CNDI at 6 months of age during an episode of gastroenteritis. We analyzed the coding regions of AVPR2 by PCR and direct DNA sequencing and identified an 80-bp duplication in exon 2 (GenBank NM_000054.4; c.800_879dup) in the proband. This variant leads to a frameshift and introduces a stop codon four codons downstream (p.Ala294Profs*4). The variant gene product either succumbs to nonsense-mediated decay or is translated to a truncated nonfunctional vasopressin V2 receptor. This variant was absent in four unaffected family members, including his parents, as well as in 100 alleles from healthy controls, and is thus considered a novel de novo disease-causing variant. Identification of the disease-causing variant facilitated precise diagnosis of CNDI in the proband. Furthermore, it allows future genetic counseling in the family. This case study highlights the importance of genetic testing in sporadic infant cases with CNDI that can occur due to de novo variants in AVPR2 or several generations of female transmission of the disease-causing variant.
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Affiliation(s)
- Shivani Joshi
- Department of Clinical Medicine, Child and Youth Research Laboratory, Aarhus University, Aarhus, Denmark
| | - Per Brandstrom
- Queen Silvia Children's Hospital, Department of Pediatrics, Institute of Clinical Sciences, Sahlgrenska Academy, Gothenburg University, Gothenburg, Sweden
| | - Niels Gregersen
- Department of Clinical Medicine, Research Unit for Molecular Medicine, Aarhus University, Aarhus, Denmark
| | - Søren Rittig
- Department of Clinical Medicine, Child and Youth Research Laboratory, Aarhus University, Aarhus, Denmark.,Department of Pediatrics, Aarhus University Hospital, Aarhus, Denmark
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8
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A 4-year-old boy presenting with persistent urinary incontinence: Answers. Pediatr Nephrol 2017; 32:769-771. [PMID: 27350624 DOI: 10.1007/s00467-016-3442-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Revised: 05/31/2016] [Accepted: 06/02/2016] [Indexed: 10/21/2022]
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9
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Makita N, Sato T, Yajima-Shoji Y, Sato J, Manaka K, Eda-Hashimoto M, Ootaki M, Matsumoto N, Nangaku M, Iiri T. Analysis of the V2 Vasopressin Receptor (V2R) Mutations Causing Partial Nephrogenic Diabetes Insipidus Highlights a Sustainable Signaling by a Non-peptide V2R Agonist. J Biol Chem 2016; 291:22460-22471. [PMID: 27601473 DOI: 10.1074/jbc.m116.733220] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 09/05/2016] [Indexed: 11/06/2022] Open
Abstract
Disease-causing mutations in G protein-coupled receptor (GPCR) genes, including the V2 vasopressin receptor (V2R) gene, often cause misfolded receptors, leading to a defect in plasma membrane trafficking. A novel V2R mutation, T273M, identified in a boy with partial nephrogenic diabetes insipidus (NDI), shows intracellular localization and partial defects similar to the two mutants we described previously (10). Although non-peptide V2R antagonists have been shown to rescue the membrane localization of V2R mutants, their level of functional rescue is weak. Interestingly, it has been reported that a non-peptide agonist, OPC51803, activates misfolded V2R mutants intracellularly without degradation, thus potentially serving as a therapeutic agent against NDI (14). In our current experiments, however, a peptide antagonist blocked arginine vasopressin (AVP)- or OPC51803-stimulated cAMP accumulation both in COS-7 and MDCK cells, suggesting that OPC51803 mainly stimulates cell surface V2R mutants. In addition, our analyses revealed that OPC51803 works not only as a non-peptide agonist that causes activation/β-arrestin-dependent desensitization of V2R mutants expressed at the plasma membrane but also as a pharmacochaperone that promotes the endoplasmic reticulum-retained mutant maturation and trafficking to the plasma membrane. The ratio of the pharmacochaperone effect to the desensitization effect likely correlates negatively with the residual function of the tested mutants, suggesting that OPC5 has a more favorable effect on the V2R mutants with a less residual function. We speculated that the canceling of the desensitization effect of OPC51803 by the pharmacochaperone effect after long-term treatment may produce sustainable signaling, and thus pharmacochaperone agonists such as OPC51803 may serve as promising therapeutics for NDI caused by misfolded V2R mutants.
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Affiliation(s)
- Noriko Makita
- From the Department of Endocrinology and Nephrology, University of Tokyo, Tokyo 113-8655, Japan,
| | - Tomohiko Sato
- the Department of Pediatrics, Hirosaki University Graduate School of Medicine, Hirosaki, 036-8562 Japan, and
| | - Yuki Yajima-Shoji
- From the Department of Endocrinology and Nephrology, University of Tokyo, Tokyo 113-8655, Japan
| | - Junichiro Sato
- From the Department of Endocrinology and Nephrology, University of Tokyo, Tokyo 113-8655, Japan
| | - Katsunori Manaka
- From the Department of Endocrinology and Nephrology, University of Tokyo, Tokyo 113-8655, Japan
| | - Makiko Eda-Hashimoto
- From the Department of Endocrinology and Nephrology, University of Tokyo, Tokyo 113-8655, Japan
| | - Masanori Ootaki
- the Department of Pharmacology, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan
| | - Naoki Matsumoto
- the Department of Pharmacology, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan
| | - Masaomi Nangaku
- From the Department of Endocrinology and Nephrology, University of Tokyo, Tokyo 113-8655, Japan
| | - Taroh Iiri
- From the Department of Endocrinology and Nephrology, University of Tokyo, Tokyo 113-8655, Japan, .,the Department of Pharmacology, St. Marianna University School of Medicine, Kawasaki 216-8511, Japan
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10
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Abstract
![]()
Whole human genome sequencing of
individuals is becoming rapid
and inexpensive, enabling new strategies for using personal genome
information to help diagnose, treat, and even prevent human disorders
for which genetic variations are causative or are known to be risk
factors. Many of the exploding number of newly discovered genetic
variations alter the structure, function, dynamics, stability, and/or
interactions of specific proteins and RNA molecules. Accordingly,
there are a host of opportunities for biochemists and biophysicists
to participate in (1) developing tools to allow accurate and sometimes
medically actionable assessment of the potential pathogenicity of
individual variations and (2) establishing the mechanistic linkage
between pathogenic variations and their physiological consequences,
providing a rational basis for treatment or preventive care. In this
review, we provide an overview of these opportunities and their associated
challenges in light of the current status of genomic science and personalized
medicine, the latter often termed precision medicine.
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Affiliation(s)
- Brett M Kroncke
- †Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States.,‡Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Carlos G Vanoye
- §Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Jens Meiler
- ‡Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States.,∥Departments of Chemistry, Pharmacology, and Bioinformatics, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Alfred L George
- §Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, United States
| | - Charles R Sanders
- †Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States.,‡Center for Structural Biology, Vanderbilt University, Nashville, Tennessee 37232, United States
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11
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Dahl LD, Corydon TJ, Ränkel L, Nielsen KM, Füchtbauer EM, Knudsen CR. An eEF1A1 truncation encoded by PTI-1 exerts its oncogenic effect inside the nucleus. Cancer Cell Int 2014; 14:17. [PMID: 24571548 PMCID: PMC3941776 DOI: 10.1186/1475-2867-14-17] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 02/20/2014] [Indexed: 11/19/2022] Open
Abstract
Background The oncogene PTI-1 was originally isolated from a prostate cancer cell line by its capability to transform rat fibroblasts. The PTI-1 mRNA has a very eccentric structure as the 5′UTR is similar to prokaryotic 23S rRNA, while the major open reading frame and the 3′UTR corresponds to a part of the mRNA encoding human translation elongation factor eEF1A1. Thus, the largest open reading frame encodes a truncated version of eEF1A1 lacking the first 67 amino acids, while having three unique N-terminal amino acids. Previously, the UTRs were shown to be a prerequisite for the transforming capacity of the PTI-1 transcript. In this study, we have investigated the possible role of the UTRs in regulating protein expression and localization. Methods The protein expression profiles of a number of PTI-1 mRNA variants were studied in vitro and in vivo. Furthermore, the oncogenic potentials of the same PTI-1 mRNAs were determined by monitoring the capacities of stably transfected cells expressing these mRNAs to induce tumors in nude mice and form foci in cell culture. Finally, the cellular localizations of PTI-1 proteins expressed from these mRNAs were determined by fluorescence microscopy. Results The PTI-1 mRNA was found to give rise to multiple protein products that potentially originate from translation initiation at downstream, inframe AUGs within the major open reading frame. At least one of the truncated protein variants was also found to be oncogenic. However, the UTRs did not appear to influence the amount and identities of these truncated protein products. In contrast, our localization studies showed that the UTRs of the transcript promote a nuclear localization of the encoded protein(s). Conclusions Translation of the PTI-1 mRNA results in multiple protein products of which (a) truncated variant(s) may play a predominant role during cellular transformation. The PTI-1 UTRs did not seem to play a role in translation regulation, but appeared to contribute to a nuclear localization of the PTI-1 protein(s). This indicates that the PTI-1 protein(s) exert(s) its/their oncogenic function inside the nucleus.
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Affiliation(s)
| | | | | | | | | | - Charlotte R Knudsen
- Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
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12
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Neocleous V, Skordis N, Shammas C, Efstathiou E, Mastroyiannopoulos NP, Phylactou LA. Identification and characterization of a novel X-linked AVPR2 mutation causing partial nephrogenic diabetes insipidus: a case report and review of the literature. Metabolism 2012; 61:922-30. [PMID: 22386940 DOI: 10.1016/j.metabol.2012.01.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 01/04/2012] [Accepted: 01/05/2012] [Indexed: 11/23/2022]
Abstract
X-linked nephrogenic diabetes insipidus (NDI) is a rare disease characterized by a malfunctioning renal response to the antidiuretic hormone arginine vasopressin (AVP) due to mutations in the AVPR2 gene. A limited number of mutations in the AVPR2 gene resulting in partial phenotype have been described so far. In this mini-review the retrospective analysis of 13 known AVPR2 mutations that have been previously shown in vitro to partially abolish AVPR2 function is described, along with a novel mutation diagnosed in a kindred with partial NDI. In the present study, a 14 year old male and his 73 year old maternal grandfather were diagnosed with partial NDI based on the clinical phenotype, the water deprivation test and the inadequate response to 1-desamino-8-d-arginine vasopressin (DDAVP) administration. Sequencing analysis of the AVPR2 gene revealed the novel missense mutation p.N317S (g.1417A > G) in both patients. This mutation was re-created by site directed mutagenesis in an AVPR2 cDNA expression vector and was functionally characterized, in terms of arginine vasopressin (AVP) and DDAVP response. AVPR2 activity of the p.N317S mutant receptor after the AVP and DDAVP administration, as assessed by cAMP production was reduced and impaired when compared to cells that expressed the wild type AVPR2 gene. In conclusion, the affected members of this family have X-linked NDI with partial resistance to AVP, due to a missense mutation in the AVPR2 gene.
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Affiliation(s)
- Vassos Neocleous
- Department of Molecular Genetics, Function and Therapy, The Cyprus Institute of Neurology and Genetics, P.O. Box 23462, 1683 Nicosia, Cyprus
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13
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Takahashi K, Makita N, Manaka K, Hisano M, Akioka Y, Miura K, Takubo N, Iida A, Ueda N, Hashimoto M, Fujita T, Igarashi T, Sekine T, Iiri T. V2 vasopressin receptor (V2R) mutations in partial nephrogenic diabetes insipidus highlight protean agonism of V2R antagonists. J Biol Chem 2011; 287:2099-106. [PMID: 22144672 DOI: 10.1074/jbc.m111.268797] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inactivating mutations of the V2 vasopressin receptor (V2R) cause cross-linked congenital nephrogenic diabetes insipidus (NDI), resulting in renal resistance to the antidiuretic hormone AVP. In two families showing partial NDI, characterized by an apparently normal response to diagnostic tests and an increase in the basal ADH levels suggesting AVP resistance, we have identified two V2R mutations, Ser-333del and Y128S. Both mutant V2Rs, when expressed in COS-7 cells, show partial defects in vasopressin-stimulated cAMP accumulation and intracellular localization. The inhibition of internalization does not rescue their localization. In contrast, the non-peptide V2R antagonists OPC41061 and OPC31260 partially rescue the membrane localization and basal function of these V2R mutants, whereas they inhibit the basal activity of the wild-type V2R. These results indicate that a partial loss of function of Ser-333del and Y128S mutant V2Rs results from defective membrane trafficking. These findings further indicate that V2R antagonists can act as protean agonists, serving as pharmacological chaperones for inactivating V2R mutants and also as inverse agonists of wild-type receptors. We speculate that this protean agonism could underlie the possible dual beneficial effects of the V2R antagonist: improvement of hyponatremia with heart failure or polycystic kidney disease and potential rescue of NDI.
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Affiliation(s)
- Kazuhiro Takahashi
- Department of Pediatrics, The University of Tokyo, Tokyo 113-8655, Japan
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