1
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Kok M, Brodsky JL. The biogenesis of potassium transporters: implications of disease-associated mutations. Crit Rev Biochem Mol Biol 2024:1-45. [PMID: 38946646 DOI: 10.1080/10409238.2024.2369986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/16/2024] [Indexed: 07/02/2024]
Abstract
The concentration of intracellular and extracellular potassium is tightly regulated due to the action of various ion transporters, channels, and pumps, which reside primarily in the kidney. Yet, potassium transporters and cotransporters play vital roles in all organs and cell types. Perhaps not surprisingly, defects in the biogenesis, function, and/or regulation of these proteins are linked to range of catastrophic human diseases, but to date, few drugs have been approved to treat these maladies. In this review, we discuss the structure, function, and activity of a group of potassium-chloride cotransporters, the KCCs, as well as the related sodium-potassium-chloride cotransporters, the NKCCs. Diseases associated with each of the four KCCs and two NKCCs are also discussed. Particular emphasis is placed on how these complex membrane proteins fold and mature in the endoplasmic reticulum, how non-native forms of the cotransporters are destroyed in the cell, and which cellular factors oversee their maturation and transport to the cell surface. When known, we also outline how the levels and activities of each cotransporter are regulated. Open questions in the field and avenues for future investigations are further outlined.
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Affiliation(s)
- Morgan Kok
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jeffrey L Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
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2
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Richter JM, Gunaga P, Yadav N, Bora RO, Bhide R, Rajugowda N, Govindrajulu K, Godesi S, Akuthota N, Rao P, Sivaraman A, Panda M, Kaspady M, Gupta A, Mathur A, Levesque PC, Gulia J, Dokania M, Ramarao M, Kole P, Chacko S, Lentz KA, Sivaprasad Lvj S, Thatipamula RP, Sridhar S, Kamble S, Govindrajan A, Soleman SI, Gordon DA, Wexler RR, Priestley ES. Discovery of BMS-986308: A Renal Outer Medullary Potassium Channel Inhibitor for the Treatment of Heart Failure. J Med Chem 2024; 67:9731-9744. [PMID: 38807539 DOI: 10.1021/acs.jmedchem.4c00893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2024]
Abstract
Recent literature reports highlight the importance of the renal outer medullary potassium (ROMK) channel in renal sodium and potassium homeostasis and emphasize the potential impact that ROMK inhibitors could have as a novel mechanism diuretic in heart failure patients. A series of piperazine-based ROMK inhibitors were designed and optimized to achieve excellent ROMK potency, hERG selectivity, and ADME properties, which led to the identification of compound 28 (BMS-986308). BMS-986308 demonstrated efficacy in the volume-loaded rat diuresis model as well as promising in vitro and in vivo profiles and was therefore advanced to clinical development.
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Affiliation(s)
- Jeremy M Richter
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Prashantha Gunaga
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Navnath Yadav
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Rajesh Onkardas Bora
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Rajeev Bhide
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Nagendra Rajugowda
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Kavitha Govindrajulu
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Sreenivasulu Godesi
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Nagarjuna Akuthota
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Prasanna Rao
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Aneesh Sivaraman
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Manoranjan Panda
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Mahammed Kaspady
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Anuradha Gupta
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Arvind Mathur
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Paul C Levesque
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Jyoti Gulia
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Manoj Dokania
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Manjunath Ramarao
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Prashant Kole
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Silvi Chacko
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Kimberley A Lentz
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Sankara Sivaprasad Lvj
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | | | - Srikanth Sridhar
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Shyam Kamble
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Arun Govindrajan
- Biocon Bristol Myers Squibb Research Center, Syngene International Limited, Bangalore 560099, India
| | - Sharif I Soleman
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - David A Gordon
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - Ruth R Wexler
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
| | - E Scott Priestley
- Bristol Myers Squibb Research & Early Development, Princeton, New Jersey 08540, United States
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3
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Morales-Olivas FJ. Diuretics use in the management of hypertension. HIPERTENSION Y RIESGO VASCULAR 2024:S1889-1837(24)00054-0. [PMID: 38853071 DOI: 10.1016/j.hipert.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Revised: 03/15/2024] [Accepted: 03/19/2024] [Indexed: 06/11/2024]
Abstract
Diuretics have been used for decades in the treatment of hypertension. Its efficacy has been demonstrated in numerous clinical trials. It is well known that the reduction in cardiovascular risk is a consequence of the reduction in blood pressure levels regardless of the drug used, but thiazide diuretics continue to be first-line drugs, especially in low doses and combined with other drugs. The debate on the advantages of using chlorthalidone or hydrochlorothiazide continues, however hydrochlorothiazide is drug most used and for which there is greater availability. The association with potassium-sparing diuretics increases the effectiveness and reduces the adverse reactions of thiazides. A new group of drugs, close to potassium-sparing diuretics, that antagonise aldosterone synthase are showing promising results as antihypertensives. There are no significant differences between men and women regarding the antihypertensive effect of thiazide diuretics.
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Affiliation(s)
- F J Morales-Olivas
- Department of Pharmacology, Faculty of Medicine and Dentistry, Universitat de València, Spain.
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4
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Laghmani K. Protein Quality Control of NKCC2 in Bartter Syndrome and Blood Pressure Regulation. Cells 2024; 13:818. [PMID: 38786040 PMCID: PMC11120568 DOI: 10.3390/cells13100818] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/03/2024] [Accepted: 05/09/2024] [Indexed: 05/25/2024] Open
Abstract
Mutations in NKCC2 generate antenatal Bartter syndrome type 1 (type 1 BS), a life-threatening salt-losing nephropathy characterized by arterial hypotension, as well as electrolyte abnormalities. In contrast to the genetic inactivation of NKCC2, inappropriate increased NKCC2 activity has been associated with salt-sensitive hypertension. Given the importance of NKCC2 in salt-sensitive hypertension and the pathophysiology of prenatal BS, studying the molecular regulation of this Na-K-2Cl cotransporter has attracted great interest. Therefore, several studies have addressed various aspects of NKCC2 regulation, such as phosphorylation and post-Golgi trafficking. However, the regulation of this cotransporter at the pre-Golgi level remained unknown for years. Similar to several transmembrane proteins, export from the ER appears to be the rate-limiting step in the cotransporter's maturation and trafficking to the plasma membrane. The most compelling evidence comes from patients with type 5 BS, the most severe form of prenatal BS, in whom NKCC2 is not detectable in the apical membrane of thick ascending limb (TAL) cells due to ER retention and ER-associated degradation (ERAD) mechanisms. In addition, type 1 BS is one of the diseases linked to ERAD pathways. In recent years, several molecular determinants of NKCC2 export from the ER and protein quality control have been identified. The aim of this review is therefore to summarize recent data regarding the protein quality control of NKCC2 and to discuss their potential implications in BS and blood pressure regulation.
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Affiliation(s)
- Kamel Laghmani
- Centre de Recherche des Cordeliers, INSERM, Sorbonne Université, Université de Paris, F-75006 Paris, France;
- CNRS, ERL8228, F-75006 Paris, France
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5
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Chen Y, Hu P, He Y, Qin H, Hu L, Yang R. Association of TyG index and central obesity with hypertension in middle-aged and elderly Chinese adults: a prospective cohort study. Sci Rep 2024; 14:2235. [PMID: 38278849 PMCID: PMC10817920 DOI: 10.1038/s41598-024-52342-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 01/17/2024] [Indexed: 01/28/2024] Open
Abstract
Triglyceride glucose index (TyG) and waist circumstance have been well documented to be highly correlated with hypertension. However, the joint effect of waist circumstance and TyG on the risk of hypertension is unknown in middle-aged and elderly Chinese adults. The purpose of this study was to investigate the association between TyG and the risk of new-onset hypertension in middle-aged and elderly Chinese individuals with different waist circumstances. The multicentred prospective cohort study was conducted in 28 provinces of China including a total of 5865 eligible participants aged ≥ 45 years old. Cox regression was performed to examine the relationship of TyG index and hypertension with adjustments for the pertinent variables. Besides, the relationship was explored in different groups on the basis of waist circumstance. There was no significant correlation between TyG index and new-onset hypertension after adjustment for pertinent variables (hazards ratio [HR]: 0.99; 95% confidence interval [CI]: 0.80-1.24). When the association was explored in different waist circumstance groups, multivariate cox regression analyses revealed that TyG was an independent factor positively associated with the risk of hypertension in central obesity prophase group (HR: 1.57; 95% CI 1.13-2.16). Among individuals with central obesity, relative to population with lower TyG (Q1: 4.96-8.18), people who had higher TyG (Q3: 8.52-8.95; Q4: 8.95-12.14) were associated with significantly lower HR for hypertension. There was no conspicuous correlation between TyG index with new-onset hypertension in normal waist circumstance (HR: 1.05; 95% CI 0.84-1.30). The research demonstrated the positive relationship of TyG with risk of hypertension among individuals with central obesity prophase, negative relationship of TyG with hypertension among population with central obesity and inconspicuous correlation of TyG with hypertension among individuals with normal waist. In conclusion, the study findings supported the combined effects of TyG index and waist circumference in predicting hypertension in middle-aged and elderly Chinese individuals.
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Affiliation(s)
- Yang Chen
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Peng Hu
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Yangyang He
- Department of Blood Transfusion, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Hao Qin
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Longlong Hu
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Renqiang Yang
- Department of Cardiology, The Second Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China.
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Ying Q, Ye Z, Zhang W, Pan Y, Dai L, Lin K, Feng X, Dong X, He F. Novel SLC12A3 gene mutations and clinical characteristics in two pedigrees with Gitelman syndrome. Clin Endocrinol (Oxf) 2023; 99:474-480. [PMID: 36562655 DOI: 10.1111/cen.14870] [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: 11/08/2022] [Revised: 12/20/2022] [Accepted: 12/22/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE Gitelman syndrome (GS) is an autosomal recessive tubulopathy resulting from inactivating mutations in the SLC12A3 gene that encodes the thiazide-sensitive sodium-chloride cotransporter (NCC). To date, more than 500 mutations have been identified in the SLC12A3 gene. In this study, we identified two new mutations in the SLC12A3 gene in two Chinese GS pedigrees. DESIGN, PATIENTS AND MEASUREMENTS The clinical characteristics and laboratory examination of two suspected GS patients in our hospital were analyzed. In addition, two pedigrees including 11 members and 2 patients underwent SLC12A3 gene analysis. RESULTS Both patients were middle-aged women with characteristics of hypokalemic metabolic alkalosis, hypomagnesemia, low level of urinary calcium and the elevated levels of renin-angiotensin-aldosterone system. So, they were clinically diagnosed as GS. Patient 2 also had type 2 diabetes and Graves' disease. Both patients were found to carry two mutations of SLC12A3 gene by Sanger direct sequencing, which were all compound heterozygous mutations. We identified three mutations in these two Chinese GS pedigrees, one of which was c.179C>T (Thr60Met). The novel c.2159G>T (p. Gly720Val) and c.2675T>C (p. Leu892Pro) mutations were strongly predicted to be pathogenic using four network programs-Polyphen-2, SIFT, Mutation Taster and LRT. CONCLUSIONS We identified two novel SLC12A3 genetic variant [c.2159G>T (p.Gly720Val) and c.2675T>C (p.Leu892Pro)] in two Chinese GS pedigrees. The discovery of new mutations has enriched the spectrum of SLC12A3 genotypes.
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Affiliation(s)
- Qiao Ying
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Zhinan Ye
- Department of Neurology, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Wei Zhang
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Yingying Pan
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Linxiong Dai
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Kaisang Lin
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
| | - Xiaocheng Feng
- Department of Endocrinology and Metabolism, School of Medicine, Zhejiang University Affiliated Sir Run Shaw Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Xuehong Dong
- Department of Endocrinology and Metabolism, School of Medicine, Zhejiang University Affiliated Sir Run Shaw Hospital, Hangzhou, Zhejiang, People's Republic of China
| | - Fei He
- Department of Endocrinology and Metabolism, Taizhou Municipal Hospital, Taizhou, Zhejiang, People's Republic of China
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7
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Nguyen NH, Sarangi S, McChesney EM, Sheng S, Durrant JD, Porter AW, Kleyman TR, Pitluk ZW, Brodsky JL. Genome mining yields putative disease-associated ROMK variants with distinct defects. PLoS Genet 2023; 19:e1011051. [PMID: 37956218 PMCID: PMC10695394 DOI: 10.1371/journal.pgen.1011051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2023] [Revised: 12/04/2023] [Accepted: 11/04/2023] [Indexed: 11/15/2023] Open
Abstract
Bartter syndrome is a group of rare genetic disorders that compromise kidney function by impairing electrolyte reabsorption. Left untreated, the resulting hyponatremia, hypokalemia, and dehydration can be fatal, and there is currently no cure. Bartter syndrome type II specifically arises from mutations in KCNJ1, which encodes the renal outer medullary potassium channel, ROMK. Over 40 Bartter syndrome-associated mutations in KCNJ1 have been identified, yet their molecular defects are mostly uncharacterized. Nevertheless, a subset of disease-linked mutations compromise ROMK folding in the endoplasmic reticulum (ER), which in turn results in premature degradation via the ER associated degradation (ERAD) pathway. To identify uncharacterized human variants that might similarly lead to premature degradation and thus disease, we mined three genomic databases. First, phenotypic data in the UK Biobank were analyzed using a recently developed computational platform to identify individuals carrying KCNJ1 variants with clinical features consistent with Bartter syndrome type II. In parallel, we examined genomic data in both the NIH TOPMed and ClinVar databases with the aid of Rhapsody, a verified computational algorithm that predicts mutation pathogenicity and disease severity. Subsequent phenotypic studies using a yeast screen to assess ROMK function-and analyses of ROMK biogenesis in yeast and human cells-identified four previously uncharacterized mutations. Among these, one mutation uncovered from the two parallel approaches (G228E) destabilized ROMK and targeted it for ERAD, resulting in reduced cell surface expression. Another mutation (T300R) was ERAD-resistant, but defects in channel activity were apparent based on two-electrode voltage clamp measurements in X. laevis oocytes. Together, our results outline a new computational and experimental pipeline that can be applied to identify disease-associated alleles linked to a range of other potassium channels, and further our understanding of the ROMK structure-function relationship that may aid future therapeutic strategies to advance precision medicine.
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Affiliation(s)
- Nga H. Nguyen
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Srikant Sarangi
- Paradigm4, Inc., Waltham, Massachusetts, United States of America
| | - Erin M. McChesney
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Shaohu Sheng
- Renal-Electrolyte Division, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Jacob D. Durrant
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Aidan W. Porter
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Thomas R. Kleyman
- Renal-Electrolyte Division, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | | | - Jeffrey L. Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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8
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Hai Y, Zhao W, Meng Q, Liu L, Wen Y. Bayesian linear mixed model with multiple random effects for family-based genetic studies. Front Genet 2023; 14:1267704. [PMID: 37928242 PMCID: PMC10620972 DOI: 10.3389/fgene.2023.1267704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 09/25/2023] [Indexed: 11/07/2023] Open
Abstract
Motivation: Family-based study design is one of the popular designs used in genetic research, and the whole-genome sequencing data obtained from family-based studies offer many unique features for risk prediction studies. They can not only provide a more comprehensive view of many complex diseases, but also utilize information in the design to further improve the prediction accuracy. While promising, existing analytical methods often ignore the information embedded in the study design and overlook the predictive effects of rare variants, leading to a prediction model with sub-optimal performance. Results: We proposed a Bayesian linear mixed model for the prediction analysis of sequencing data obtained from family-based studies. Our method can not only capture predictive effects from both common and rare variants, but also easily accommodate various disease model assumptions. It uses information embedded in the study design to form surrogates, where the predictive effects from unmeasured/unknown genetic and environmental risk factors can be modelled. Through extensive simulation studies and the analysis of sequencing data obtained from the Michigan State University Twin Registry study, we have demonstrated that the proposed method outperforms commonly adopted techniques. Availability: R package is available at https://github.com/yhai943/FBLMM.
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Affiliation(s)
- Yang Hai
- Department of Statistics, University of Auckland, Auckland, New Zealand
| | - Wenxuan Zhao
- Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Qingyu Meng
- Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Long Liu
- Department of Health Statistics, School of Public Health, Shanxi Medical University, Taiyuan, China
| | - Yalu Wen
- Department of Statistics, University of Auckland, Auckland, New Zealand
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9
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Tanveer Y, Sanipini S, Khleif R, Tsenteradze T, Gapizov A, Grezenko H, Affaf M, Abdelaziz AM, Rehman A, Zia U, Jama H, Shehryar A, Mohsin SN, Ekhator C, Khan R. Transforming Medical Paradigms: A Cutting-Edge Review of Genomic and Robotic Medical and Surgical Approaches in the Battle Against Diabetes, Hypertension, and Cardiovascular Issues. Cureus 2023; 15:e46998. [PMID: 37965396 PMCID: PMC10641027 DOI: 10.7759/cureus.46998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2023] [Indexed: 11/16/2023] Open
Abstract
This article provides an in-depth review of the current state of management for diabetes, hypertension, and cardiovascular disease, focusing on advancements from genomics to robotics. It explores the role of genomic markers in personalized medicine, offering tailored treatment options for these chronic conditions. The article also examines the efficacy of various pharmacological and surgical interventions, including bariatric surgery for diabetes and device-based treatments for hypertension. A comparative analysis is presented to evaluate the cost-effectiveness and patient outcomes between medical and surgical approaches. The review concludes that while personalized medicine and minimally invasive surgical techniques show promise, more high-quality comparative research is needed. The ultimate goal is to integrate these emerging technologies within a framework of evidence-based medicine to improve patient outcomes and health equity.
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Affiliation(s)
| | | | - Rafeef Khleif
- Medical School, Xavier University School of Medicine, Oranjestad, ABW
| | - Tamar Tsenteradze
- General Surgery, Tbilisi State Medical Univerity, Tbilisi, GEO
- Cardiology, Tbilisi State Medical Univerity, Tbilisi, GEO
- Internal Medicine, Tbilisi State Medical Univerity, Tbilisi, GEO
| | - Abubakar Gapizov
- General Surgery, American University of Antigua, Saint George, ATG
| | - Han Grezenko
- Translational Neuroscience, Barrow Neurological Institute, Phoenix, USA
| | - Maryam Affaf
- Internal Medicine, Women's Medical and Dental College, Abbotabad, PAK
| | - Ali M Abdelaziz
- Internal Medicine, Alexandria University Faculty of Medicine, Alexandria, EGY
| | | | - Umar Zia
- Internal Medicine, Khyber Medical University, Peshawar, PAK
| | - Huda Jama
- Internal Medicine, Nishtar Medical University, Multan, PAK
| | | | | | - Chukwuyem Ekhator
- Neuro-Oncology, New York Institute of Technology, College of Osteopathic Medicine, Old Westbury, USA
| | - Rehman Khan
- Internal Medicine, Mayo Hospital, Lahore, PAK
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10
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Gamba G. Thirty years of the NaCl cotransporter: from cloning to physiology and structure. Am J Physiol Renal Physiol 2023; 325:F479-F490. [PMID: 37560773 PMCID: PMC10639029 DOI: 10.1152/ajprenal.00114.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/11/2023] Open
Abstract
The primary structure of the thiazide-sensitive NaCl cotransporter (NCC) was resolved 30 years ago by the molecular identification of the cDNA encoding this cotransporter, from the winter's flounder urinary bladder, following a functional expression strategy. This review outlines some aspects of how the knowledge about thiazide diuretics and NCC evolved, the history of the cloning process, and the expansion of the SLC12 family of electroneutral cotransporters. The diseases associated with activation or inactivation of NCC are discussed, as well as the molecular model by which the activity of NCC is regulated. The controversies in the field are discussed as well as recent publication of the three-dimensional model of NCC obtained by cryo-electron microscopy, revealing not only the amino acid residues critical for Na+ and Cl- translocation but also the residues critical for polythiazide binding to the transporter, opening the possibility for a new era in thiazide diuretic therapy.
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Affiliation(s)
- Gerardo Gamba
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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11
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Kettritz R, Loffing J. Potassium homeostasis - Physiology and pharmacology in a clinical context. Pharmacol Ther 2023; 249:108489. [PMID: 37454737 DOI: 10.1016/j.pharmthera.2023.108489] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/03/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
Membrane voltage controls the function of excitable cells and is mainly a consequence of the ratio between the extra- and intracellular potassium concentration. Potassium homeostasis is safeguarded by balancing the extra-/intracellular distribution and systemic elimination of potassium to the dietary potassium intake. These processes adjust the plasma potassium concentration between 3.5 and 4.5 mmol/L. Several genetic and acquired diseases but also pharmacological interventions cause dyskalemias that are associated with increased morbidity and mortality. The thresholds at which serum K+ not only associates but also causes increased mortality are hotly debated. We discuss physiologic, pathophysiologic, and pharmacologic aspects of potassium regulation and provide informative case vignettes. Our aim is to help clinicians, epidemiologists, and pharmacologists to understand the complexity of the potassium homeostasis in health and disease and to initiate appropriate treatment strategies in dyskalemic patients.
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Affiliation(s)
- Ralph Kettritz
- Department of Nephrology and Medical Intensive Care, Charité - Universitätsmedizin Berlin, Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany; Experimental and Clinical Research Center, Max Delbrück Center for Molecular Medicine in the Helmholtz Association and Charité Universitätsmedizin Berlin, Germany.
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12
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Tschernoster N, Erger F, Kohl S, Reusch B, Wenzel A, Walsh S, Thiele H, Becker C, Franitza M, Bartram MP, Kömhoff M, Schumacher L, Kukat C, Borodina T, Quedenau C, Nürnberg P, Rinschen MM, Driller JH, Pedersen BP, Schlingmann KP, Hüttel B, Bockenhauer D, Beck B, Altmüller J. Long-read sequencing identifies a common transposition haplotype predisposing for CLCNKB deletions. Genome Med 2023; 15:62. [PMID: 37612755 PMCID: PMC10464140 DOI: 10.1186/s13073-023-01215-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 07/27/2023] [Indexed: 08/25/2023] Open
Abstract
BACKGROUND Long-read sequencing is increasingly used to uncover structural variants in the human genome, both functionally neutral and deleterious. Structural variants occur more frequently in regions with a high homology or repetitive segments, and one rearrangement may predispose to additional events. Bartter syndrome type 3 (BS 3) is a monogenic tubulopathy caused by deleterious variants in the chloride channel gene CLCNKB, a high proportion of these being large gene deletions. Multiplex ligation-dependent probe amplification, the current diagnostic gold standard for this type of mutation, will indicate a simple homozygous gene deletion in biallelic deletion carriers. However, since the phenotypic spectrum of BS 3 is broad even among biallelic deletion carriers, we undertook a more detailed analysis of precise breakpoint regions and genomic structure. METHODS Structural variants in 32 BS 3 patients from 29 families and one BS4b patient with CLCNKB deletions were investigated using long-read and synthetic long-read sequencing, as well as targeted long-read sequencing approaches. RESULTS We report a ~3 kb duplication of 3'-UTR CLCNKB material transposed to the corresponding locus of the neighbouring CLCNKA gene, also found on ~50 % of alleles in healthy control individuals. This previously unknown common haplotype is significantly enriched in our cohort of patients with CLCNKB deletions (45 of 51 alleles with haplotype information, 2.2 kb and 3.0 kb transposition taken together, p=9.16×10-9). Breakpoint coordinates for the CLCNKB deletion were identifiable in 28 patients, with three being compound heterozygous. In total, eight different alleles were found, one of them a complex rearrangement with three breakpoint regions. Two patients had different CLCNKA/CLCNKB hybrid genes encoding a predicted CLCNKA/CLCNKB hybrid protein with likely residual function. CONCLUSIONS The presence of multiple different deletion alleles in our cohort suggests that large CLCNKB gene deletions originated from many independently recurring genomic events clustered in a few hot spots. The uncovered associated sequence transposition haplotype apparently predisposes to these additional events. The spectrum of CLCNKB deletion alleles is broader than expected and likely still incomplete, but represents an obvious candidate for future genotype/phenotype association studies. We suggest a sensitive and cost-efficient approach, consisting of indirect sequence capture and long-read sequencing, to analyse disease-relevant structural variant hotspots in general.
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Affiliation(s)
- Nikolai Tschernoster
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Florian Erger
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Stefan Kohl
- Department of Pediatrics, Cologne Children's Hospital, Cologne, Germany
| | - Björn Reusch
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Andrea Wenzel
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Stephen Walsh
- Department of Renal Medicine, UCL, University College London, London, UK
| | - Holger Thiele
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Christian Becker
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Marek Franitza
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Malte P Bartram
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Department II of Internal Medicine, University of Cologne, Cologne, Germany
| | - Martin Kömhoff
- Department of Pediatrics, University Marburg, Marburg, Germany
| | - Lena Schumacher
- FACS & Imaging Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Christian Kukat
- FACS & Imaging Core Facility, Max Planck Institute for Biology of Ageing, Cologne, Germany
| | - Tatiana Borodina
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany
| | - Claudia Quedenau
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany
| | - Peter Nürnberg
- Cologne Center for Genomics (CCG), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Markus M Rinschen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
- Department III of Medicine, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Jan H Driller
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000, Aarhus C, Denmark
| | - Bjørn P Pedersen
- Department of Molecular Biology and Genetics, Aarhus University, Universitetsbyen 81, DK-8000, Aarhus C, Denmark
| | - Karl P Schlingmann
- Department of General Pediatrics, University Children's Hospital, Münster, Germany
| | - Bruno Hüttel
- Max Planck Genome-Centre Cologne, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Detlef Bockenhauer
- Department of Renal Medicine, UCL, University College London, London, UK
- Great Ormond Street Hospital for Children, NHS Foundation Trust, London, UK
| | - Bodo Beck
- Institute of Human Genetics, Faculty of Medicine and University Hospital Cologne, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - Janine Altmüller
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Hannoversche Straße 28, 10115, Berlin, Germany.
- Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Core Facility Genomics, Berlin, Germany.
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Sánchez-Lozada LG, Madero M, Mazzali M, Feig DI, Nakagawa T, Lanaspa MA, Kanbay M, Kuwabara M, Rodriguez-Iturbe B, Johnson RJ. Sugar, salt, immunity and the cause of primary hypertension. Clin Kidney J 2023; 16:1239-1248. [PMID: 37529651 PMCID: PMC10387395 DOI: 10.1093/ckj/sfad058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Indexed: 08/03/2023] Open
Abstract
Despite its discovery more than 150 years ago, the cause of primary hypertension remains unknown. Most studies suggest that hypertension involves genetic, congenital or acquired risk factors that result in a relative inability of the kidney to excrete salt (sodium chloride) in the kidneys. Here we review recent studies that suggest there may be two phases, with an initial phase driven by renal vasoconstriction that causes low-grade ischemia to the kidney, followed by the infiltration of immune cells that leads to a local autoimmune reaction that maintains the renal vasoconstriction. Evidence suggests that multiple mechanisms could trigger the initial renal vasoconstriction, but one way may involve fructose that is provided in the diet (such as from table sugar or high fructose corn syrup) or produced endogenously. The fructose metabolism increases intracellular uric acid, which recruits NADPH oxidase to the mitochondria while inhibiting AMP-activated protein kinase. A drop in intracellular ATP level occurs, triggering a survival response. Leptin levels rise, triggering activation of the sympathetic central nervous system, while vasopressin levels rise, causing vasoconstriction in its own right and stimulating aldosterone production via the vasopressin 1b receptor. Low-grade renal injury and autoimmune-mediated inflammation occur. High-salt diets can amplify this process by raising osmolality and triggering more fructose production. Thus, primary hypertension may result from the overactivation of a survival response triggered by fructose metabolism. Restricting salt and sugar and hydrating with ample water may be helpful in the prevention of primary hypertension.
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Affiliation(s)
- Laura G Sánchez-Lozada
- Department of Cardio-Renal Physiopathology, Instituto Nacional de Cardiología “Ignacio Chavez”, Mexico City, Mexico
| | - Magdalena Madero
- Division of Nephrology, Department of Medicine, Instituto Nacional de Cardiología “Ignacio Chavez”, Mexico City, Mexico
| | - Marilda Mazzali
- Division of Nephrology, University of Campinas, São Paulo, Brazil
| | - Daniel I Feig
- Division of Pediatric Nephrology, University of Alabama, Birmingham, AL, USA
| | | | - Miguel A Lanaspa
- Department of Medicine, University of Colorado Anschutz Medical Center, Aurora, CO, USA
| | - Mehmet Kanbay
- Department of Medicine, Koc University School of Medicine, Istanbul, Turkey
| | | | - Bernardo Rodriguez-Iturbe
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición “Salvador Zubirán”, Mexico City
| | - Richard J Johnson
- Department of Medicine, University of Colorado Anschutz Medical Center, Aurora, CO, USA
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Nguyen NH, Sarangi S, McChesney EM, Sheng S, Porter AW, Kleyman TR, Pitluk ZW, Brodsky JL. Genome mining yields new disease-associated ROMK variants with distinct defects. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.05.539609. [PMID: 37214976 PMCID: PMC10197530 DOI: 10.1101/2023.05.05.539609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Bartter syndrome is a group of rare genetic disorders that compromise kidney function by impairing electrolyte reabsorption. Left untreated, the resulting hyponatremia, hypokalemia, and dehydration can be fatal. Although there is no cure for this disease, specific genes that lead to different Bartter syndrome subtypes have been identified. Bartter syndrome type II specifically arises from mutations in the KCNJ1 gene, which encodes the renal outer medullary potassium channel, ROMK. To date, over 40 Bartter syndrome-associated mutations in KCNJ1 have been identified. Yet, their molecular defects are mostly uncharacterized. Nevertheless, a subset of disease-linked mutations compromise ROMK folding in the endoplasmic reticulum (ER), which in turn results in premature degradation via the ER associated degradation (ERAD) pathway. To identify uncharacterized human variants that might similarly lead to premature degradation and thus disease, we mined three genomic databases. First, phenotypic data in the UK Biobank were analyzed using a recently developed computational platform to identify individuals carrying KCNJ1 variants with clinical features consistent with Bartter syndrome type II. In parallel, we examined ROMK genomic data in both the NIH TOPMed and ClinVar databases with the aid of a computational algorithm that predicts protein misfolding and disease severity. Subsequent phenotypic studies using a high throughput yeast screen to assess ROMK function-and analyses of ROMK biogenesis in yeast and human cells-identified four previously uncharacterized mutations. Among these, one mutation uncovered from the two parallel approaches (G228E) destabilized ROMK and targeted it for ERAD, resulting in reduced protein expression at the cell surface. Another ERAD-targeted ROMK mutant (L320P) was found in only one of the screens. In contrast, another mutation (T300R) was ERAD-resistant, but defects in ROMK activity were apparent after expression and two-electrode voltage clamp measurements in Xenopus oocytes. Together, our results outline a new computational and experimental pipeline that can be applied to identify disease-associated alleles linked to a range of other potassium channels, and further our understanding of the ROMK structure-function relationship that may aid future therapeutic strategies. Author Summary Bartter syndrome is a rare genetic disorder characterized by defective renal electrolyte handing, leading to debilitating symptoms and, in some patients, death in infancy. Currently, there is no cure for this disease. Bartter syndrome is divided into five types based on the causative gene. Bartter syndrome type II results from genetic variants in the gene encoding the ROMK protein, which is expressed in the kidney and assists in regulating sodium, potassium, and water homeostasis. Prior work established that some disease-associated ROMK mutants misfold and are destroyed soon after their synthesis in the endoplasmic reticulum (ER). Because a growing number of drugs have been identified that correct defective protein folding, we wished to identify an expanded cohort of similarly misshapen and unstable disease-associated ROMK variants. To this end, we developed a pipeline that employs computational analyses of human genome databases with genetic and biochemical assays. Next, we both confirmed the identity of known variants and uncovered previously uncharacterized ROMK variants associated with Bartter syndrome type II. Further analyses indicated that select mutants are targeted for ER-associated degradation, while another mutant compromises ROMK function. This work sets-the-stage for continued mining for ROMK loss of function alleles as well as other potassium channels, and positions select Bartter syndrome mutations for correction using emerging pharmaceuticals.
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Cai L, Wang D, Gui T, Wang X, Zhao L, Boron WF, Chen LM, Liu Y. Dietary sodium enhances the expression of SLC4 family transporters, IRBIT, L-IRBIT, and PP1 in rat kidney: Insights into the molecular mechanism for renal sodium handling. Front Physiol 2023; 14:1154694. [PMID: 37082243 PMCID: PMC10111226 DOI: 10.3389/fphys.2023.1154694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 03/24/2023] [Indexed: 04/07/2023] Open
Abstract
The kidney plays a central role in maintaining the fluid and electrolyte homeostasis in the body. Bicarbonate transporters NBCn1, NBCn2, and AE2 are expressed at the basolateral membrane of the medullary thick ascending limb (mTAL). In a previous study, NBCn1, NBCn2, and AE2 are proposed to play as a regulatory pathway to decrease NaCl reabsorption in the mTAL under high salt condition. When heterologously expressed, the activity of these transporters could be stimulated by the InsP3R binding protein released with inositol 1,4,5-trisphosphate (IRBIT), L-IRBIT (collectively the IRBITs), or protein phosphatase PP1. In the present study, we characterized by immunofluorescence the expression and localization of the IRBITs, and PP1 in rat kidney. Our data showed that the IRBITs were predominantly expressed from the mTAL through the distal renal tubules. PP1 was predominantly expressed in the TAL, but is also present in high abundance from the distal convoluted tubule through the medullary collecting duct. Western blotting analyses showed that the abundances of NBCn1, NBCn2, and AE2 as well as the IRBITs and PP1 were greatly upregulated in rat kidney by dietary sodium. Co-immunoprecipitation study provided the evidence for protein interaction between NBCn1 and L-IRBIT in rat kidney. Taken together, our data suggest that the IRBITs and PP1 play an important role in sodium handling in the kidney. We propose that the IRBITs and PP1 stimulates NBCn1, NBCn2, and AE2 in the basolateral mTAL to inhibit sodium reabsorption under high sodium condition. Our study provides important insights into understanding the molecular mechanism for the regulation of sodium homeostasis in the body.
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Affiliation(s)
- Lu Cai
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Dengke Wang
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Tianxiang Gui
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Xiaoyu Wang
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Lingyu Zhao
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Walter F. Boron
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, OH, United States
| | - Li-Ming Chen
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- *Correspondence: Li-Ming Chen, ; Ying Liu,
| | - Ying Liu
- Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei, China
- *Correspondence: Li-Ming Chen, ; Ying Liu,
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Church JA, Grigorenko EL, Fletcher JM. The Role of Neural and Genetic Processes in Learning to Read and Specific Reading Disabilities: Implications for Instruction. READING RESEARCH QUARTERLY 2023; 58:203-219. [PMID: 37456924 PMCID: PMC10348696 DOI: 10.1002/rrq.439] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 06/29/2021] [Indexed: 07/18/2023]
Abstract
To learn to read, the brain must repurpose neural systems for oral language and visual processing to mediate written language. We begin with a description of computational models for how alphabetic written language is processed. Next, we explain the roles of a dorsal sublexical system in the brain that relates print and speech, a ventral lexical system that develops the visual expertise for rapid orthographic processing at the word level, and the role of cognitive control networks that regulate attentional processes as children read. We then use studies of children, adult illiterates learning to read, and studies of poor readers involved in intervention, to demonstrate the plasticity of these neural networks in development and in relation to instruction. We provide a brief overview of the rapid increase in the field's understanding and technology for assessing genetic influence on reading. Family studies of twins have shown that reading skills are heritable, and molecular genetic studies have identified numerous regions of the genome that may harbor candidate genes for the heritability of reading. In selected families, reading impairment has been associated with major genetic effects, despite individual gene contributions across the broader population that appear to be small. Neural and genetic studies do not prescribe how children should be taught to read, but these studies have underscored the critical role of early intervention and ongoing support. These studies also have highlighted how structured instruction that facilitates access to the sublexical components of words is a critical part of training the brain to read.
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Affiliation(s)
| | - Elena L Grigorenko
- University of Houston, Texas, USA; Baylor College of Medicine, Houston, Texas, USA; and St. Petersburg State University, Russia
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Tanaka Y, Muramatsu M, Miyauchi Y, Suzuki Y, Morohashi T, Nozu K. A case of advanced breast cancer with Gitelman syndrome. Int Cancer Conf J 2023; 12:137-142. [PMID: 36896203 PMCID: PMC9989089 DOI: 10.1007/s13691-022-00593-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 12/29/2022] [Indexed: 01/05/2023] Open
Abstract
Gitelman syndrome (GS) is a rare, mostly autosomal recessive disease this is a salt-losing tubulopathy caused by mutation of genes encoding sodium chloride (NCCT) and magnesium transporters in the thiazide-sensitive segments of the distal nephron. We encountered a 45-year-old female who has suffered from whole-body weakness because of hypokalemia for 8 years and diagnosed with Gitelman syndrome clinically. She visited the hospital with a complaint of an unrelieved hard mass of the left breast. The tumor was diagnosed as human epidermal growth factor receptor 2 (HER2)-positive breast cancer. We herein report this first case of a breast cancer patient with Gitelman syndrome who developed other neoplasms including colon polyp, adrenal adenoma, an ovarian cyst, and multiple uterine fibroids and provide a review of the pertinent literature.
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Affiliation(s)
- Yuko Tanaka
- Breast Center, Dokkyo Medical University Hospital, 880 Kitakobayashi, Mibu, Shimotsuga District, Tochigi, 321-0293 Japan
- Department of Cancer Genome, Dokkyo Medical University Hospital, 880 Kitakobayashi, Mibu, Shimotsuga District, Tochigi, 321-0293 Japan
| | - Miyuki Muramatsu
- Department of Cancer Genome, Dokkyo Medical University Hospital, 880 Kitakobayashi, Mibu, Shimotsuga District, Tochigi, 321-0293 Japan
| | - Yoshihiro Miyauchi
- Department of Nephrology, Asahi General Hospital, I-1326, Asahi, Chiba 289-2511 Japan
| | - Yoshio Suzuki
- Department of Clinical Pathology, Asahi General Hospital, I-1326, Asahi, Chiba 289-2511 Japan
| | - Tamaki Morohashi
- Department of Pediatrics and Child Health, Nihon University School of Medicine, 30-1 Oyaguchi Kamimachi, Itabashi-ku, Tokyo, 173-8610 Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, 7-5-2 Kusunoki-cho, Chuo-ku, Kobe, 650-0017 Japan
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Sgarabotto L, Ravarotto V, Stefanelli LF, Cacciapuoti M, Davis PA, Nalesso F, Calò LA. Oxidants and Cardiorenal Vascular Remodeling—Insights from Rare Genetic Tubulopathies: Bartter’s and Gitelman’s Syndromes. Antioxidants (Basel) 2023; 12:antiox12040811. [PMID: 37107186 PMCID: PMC10135094 DOI: 10.3390/antiox12040811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/12/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023] Open
Abstract
Two human genetic tubulopathies, Bartter’s (BS) and Gitelman’s (GS) syndromes, have normo/hypotension and absent cardiac remodeling despite their apparent angiotensin system (RAS) activation. This seeming contradiction has led to an extensive investigation of BSGS patients, the result of which is that BSGS represents a mirror image of hypertension. BSGS’s unique set of properties has then permitted their use as a human model to probe and characterize RAS system pathways and oxidative stress in cardiovascular and renal remodeling and pathophysiology. This review details the results using GSBS patients that provide a deeper understanding of Ang II signaling and its associated oxidants/oxidative stress in humans. By providing a more complete and complex picture of cardiovascular and renal remodeling pathways and processes, studies of GSBS can inform the identification and selection of new targets and therapies to treat these and other oxidant-related disorders.
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Affiliation(s)
- Luca Sgarabotto
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine, University of Padova, 35128 Padova, Italy
| | - Verdiana Ravarotto
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine, University of Padova, 35128 Padova, Italy
| | - Lucia Federica Stefanelli
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine, University of Padova, 35128 Padova, Italy
| | - Martina Cacciapuoti
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine, University of Padova, 35128 Padova, Italy
| | - Paul A. Davis
- Department of Nutrition, University of California, Davis, CA 95616, USA
| | - Federico Nalesso
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine, University of Padova, 35128 Padova, Italy
| | - Lorenzo A. Calò
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine, University of Padova, 35128 Padova, Italy
- Correspondence: ; Tel.: +39-049-8213071
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Choi N, Kim SH, Bae EH, Yang EM, Lee GH, Lee SH, Lee JH, Ahn YH, Cheong HI, Kang HG, Hyun HS, Kim JH. Long-term outcome of Bartter syndrome in 54 patients: A multicenter study in Korea. Front Med (Lausanne) 2023; 10:1099840. [PMID: 36993809 PMCID: PMC10040751 DOI: 10.3389/fmed.2023.1099840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Accepted: 02/16/2023] [Indexed: 03/14/2023] Open
Abstract
IntroductionBartter syndrome (BS) is a rare salt-wasting tubulopathy caused by mutations in genes encoding sodium, potassium, or chloride transporters of the thick ascending limb of the loop of Henle and/or the distal convoluted tubule of the kidney. BS is characterized by polyuria, failure to thrive, hypokalemia, metabolic alkalosis, hyperreninemia, and hyperaldosteronism. Potassium and/or sodium supplements, potassium-sparing diuretics, and nonsteroidal anti-inflammatory drugs can be used to treat BS. While its symptoms and initial management are relatively well known, long-term outcomes and treatments are scarce.MethodsWe retrospectively reviewed 54 Korean patients who were clinically or genetically diagnosed with BS from seven centers in Korea.ResultsAll patients included in this study were clinically or genetically diagnosed with BS at a median age of 5 (range, 0–271) months, and their median follow-up was 8 (range, 0.5–27) years. Genetic diagnosis of BS was confirmed in 39 patients: 4 had SLC12A1 gene mutations, 1 had KCNJ1 gene mutations, 33 had CLCNKB gene mutations, and 1 had BSND mutation. Potassium chloride supplements and potassium-sparing diuretics were administered in 94% and 68% of patients, respectively. The mean dosage of potassium chloride supplements was 5.0 and 2.1 mEq/day/kg for patients younger and older than 18 years, respectively. Nephrocalcinosis was a common finding of BS, and it also improved with age in some patients. At the last follow-up of 8 years after the initial diagnosis, 41% had short stature (height less than 3rd percentile) and impaired kidney function was observed in six patients [chronic kidney disease (CKD) G3, n = 4; CKD G5, n = 2].ConclusionBS patients require a large amount of potassium supplementation along with potassium-sparing agents throughout their lives, but tend to improve with age. Despite management, a significant portion of this population exhibited growth impairment, while 11% developed CKD G3–G5.
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Affiliation(s)
- Naye Choi
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
| | - Seong Heon Kim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
| | - Eun Hui Bae
- Department of Internal Medicine, Medical School, Chonnam National University, Gwangju, Republic of Korea
| | - Eun Mi Yang
- Department of Pediatrics, Chonnam National University Hospital, Gwangju, Republic of Korea
| | - Geum Hwa Lee
- Department of Pediatrics, Yonsei University Severance Children's Hospital, Seoul, Republic of Korea
| | - Sang-Ho Lee
- Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, Seoul, Republic of Korea
| | - Joo Hoon Lee
- Department of Pediatrics, Ulsan University Asan Medical Center, Seoul, Republic of Korea
| | - Yo Han Ahn
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Kidney Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
| | - Hae Il Cheong
- Department of Pediatrics, Hallym University Sacred Heart Hospital, Anyang, Republic of Korea
| | - Hee Gyung Kang
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul, Republic of Korea
- Kidney Research Institute, Seoul National University Medical Research Center, Seoul, Republic of Korea
- Wide River Institute of Immunology, Seoul National University, Hongcheon, Republic of Korea
| | - Hye Sun Hyun
- Department of Pediatrics, Collage of Medicine, St. Vincent's Hospital, The Catholic University of Korea, Seoul, Republic of Korea
- *Correspondence: Hye Sun Hyun,
| | - Ji Hyun Kim
- Department of Pediatrics, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pediatrics, Seoul National University Bundang Hospital, Seongnam, Republic of Korea
- Ji Hyun Kim,
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Guo W, Ji P, Xie Y. Genetic diagnosis and treatment of hereditary renal tubular disease with hypokalemia and alkalosis. J Nephrol 2023; 36:575-591. [PMID: 35994232 DOI: 10.1007/s40620-022-01428-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 07/29/2022] [Indexed: 10/15/2022]
Abstract
Renal tubules play an important role in maintaining water, electrolyte, and acid-base balance. Renal tubule dysfunction can cause electrolyte disorders and acid-base imbalance. Clinically, hypokalemic renal tubular disease is the most common tubule disorder. With the development of molecular genetics and gene sequencing technology, hereditary renal tubular diseases have attracted attention, and an increasing number of pathogenic genes related to renal tubular diseases have been discovered and reported. Inherited renal tubular diseases mainly occur due to mutations in genes encoding various specific transporters or ion channels expressed on the tubular epithelial membrane, leading to dysfunctional renal tubular reabsorption, secretion, and excretion. An in-depth understanding of the molecular genetic basis of hereditary renal tubular disease will help to understand the physiological function of renal tubules, the mechanism by which the kidney maintains water, electrolyte, and acid-base balance, and the relationship between the kidney and other systems in the body. Meanwhile, understanding these diseases also improves our understanding of the pathogenesis of hypokalemia, alkalosis and other related diseases and ultimately promotes accurate diagnostics and effective disease treatment. The present review summarizes the most common hereditary renal tubular diseases (Bartter syndrome, Gitelman syndrome, EAST syndrome and Liddle syndrome) characterized by hypokalemia and alkalosis. Further detailed explanations are provided for pathogenic genes and functional proteins, clinical manifestations, intrinsic relationship between genotype and clinical phenotype, diagnostic clues, differential diagnosis, and treatment strategies for these diseases.
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Affiliation(s)
- Wenkai Guo
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China
| | - Pengcheng Ji
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China
| | - Yuansheng Xie
- Department of Nephrology, First Medical Center of Chinese PLA General Hospital, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Beijing, 100853, People's Republic of China.
- School of Medicine, Nankai University, Tianjin, 300071, People's Republic of China.
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21
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Wan ER, Iancu D, Ashton E, Siew K, Mohidin B, Sung CC, Nagano C, Bockenhauer D, Lin SH, Nozu K, Walsh SB. Machine Learning to Identify Genetic Salt-Losing Tubulopathies in Hypokalemic Patients. Kidney Int Rep 2023; 8:556-565. [PMID: 36938092 PMCID: PMC10014379 DOI: 10.1016/j.ekir.2022.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/29/2022] [Accepted: 12/12/2022] [Indexed: 12/25/2022] Open
Abstract
Introduction Clinically distinguishing patients with the inherited salt-losing tubulopathies (SLTs), Gitelman or Bartter syndrome (GS or BS) from other causes of hypokalemia (LK) patients is difficult, and genotyping is costly. We decided to identify clinical characteristics that differentiate SLTs from LK. Methods A total of 66 hypokalemic patients with possible SLTs were recruited to a prospective observational cohort study at the University College London Renal Tubular Clinic, London. All patients were genotyped for pathogenic variants in genes which cause SLTs; 39 patients had pathogenic variants in genes causing SLTs. We obtained similar data sets from cohorts in Taipei and Kobe, as follows: the combined data set comprised 419 patients; 291 had genetically confirmed SLT. London and Taipei data sets were combined to train machine learning (ML) algorithms, which were then tested on the Kobe data set. Results Single biochemical variables (e.g., plasma renin) were significantly, but inconsistently, different between SLTs and LK in all cohorts. A decision table algorithm using serum bicarbonate and urinary sodium excretion (FENa) achieved a classification accuracy of 74%. This was superior to all the single biochemical variables identified previously. Conclusion ML algorithms can differentiate true SLT in the context of a specialist clinic with some accuracy. However, based on routine biochemistry, the accuracy is insufficient to make genotyping redundant.
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Affiliation(s)
- Elizabeth R. Wan
- Department of Renal Medicine, University College London, London, UK
| | - Daniela Iancu
- Department of Renal Medicine, University College London, London, UK
| | - Emma Ashton
- North East Thames Regional Genetics Service Laboratories, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - Keith Siew
- Department of Renal Medicine, University College London, London, UK
| | - Barian Mohidin
- Department of Renal Medicine, University College London, London, UK
| | - Chih-Chien Sung
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Detlef Bockenhauer
- Department of Renal Medicine, University College London, London, UK
- Department of Pediatric Nephrology, Great Ormond Street Hospital for Children National Health Service Foundation Trust, London, UK
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Stephen B. Walsh
- Department of Renal Medicine, University College London, London, UK
- Correspondence: Stephen B. Walsh, Department of Renal Medicine, University College London, 1st Floor Medical School, Royal Free Hospital, Rowland Hill Street, Hampstead, London, NW3 2PF, UK.
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22
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Kawahara T, Inazu T, Ishida S. Total colectomy for poorly controlled hypokalaemia due to Gitelman syndrome. BMJ Case Rep 2023; 16:e252916. [PMID: 36750303 PMCID: PMC9906164 DOI: 10.1136/bcr-2022-252916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
Gitelman syndrome (GS) is an autosomal recessive tubulopathy caused by dysfunction of the thiazide-sensitive sodium-chloride cotransporter, which leads to hypokalaemia, metabolic alkalosis, hypomagnesaemia and hypocalciuria. Patients with GS show varied clinical features due to hypokalaemia: tetany, muscle weakness, periodical paralysis and constipation, which is one of the most frequent ones. This paper presents the case of a woman in her 40s referred to our endocrinology department for severe hypokalaemia. After biochemical and genetic analyses, a diagnosis of GS was established. Concurrently, the patient suffered from refractory constipation due to hypokalaemia and underwent a total colectomy with ileorectal anastomosis, which cured both disorders without any medication for 3 years.
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Affiliation(s)
- Tetsuya Kawahara
- Endocrinology and Metabolism, Shin Komonji Hospital, Kitakyushu, Fukuoka, Japan
| | - Tetsuya Inazu
- College of Pharmaceutical Science, Ritsumeikan University-Biwako Kusatsu Campus, Kusatsu, Shiga, Japan
| | - Shingo Ishida
- Surgery, Shin Komonji Hospital, Kitakyushu, Fukuoka, Japan
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23
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Morrison AR. Magnesium Homeostasis: Lessons from Human Genetics. Clin J Am Soc Nephrol 2023; 18:01277230-990000000-00067. [PMID: 36723340 PMCID: PMC10356123 DOI: 10.2215/cjn.0000000000000103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 01/20/2023] [Indexed: 02/02/2023]
Abstract
Mg2+, the fourth most abundant cation in the body, serves as a co-factor for about 600 cellular enzymes. One third of ingested Mg2+ is absorbed from the gut through a saturable transcellular process and a concentration-dependent paracellular process. Absorbed Mg2+ is excreted by the kidney and maintains serum Mg2+ within a narrow range of 0.7 to 1.25 mmol/L. The reabsorption of Mg2+ by the nephron is characterized by paracellular transport in the proximal tubule and thick ascending limb. The nature of the transport pathways in the gut epithelia and thick ascending limb has emerged from an understanding of the molecular mechanisms responsible for rare monogenetic disorders presenting with clinical hypomagnesemia. These human disorders due to loss-of function mutations, in concert with mouse models have led to a deeper understanding of Mg2+ transport in the gut and renal tubule. This review focuses on the nature of the transporters and channels revealed by human and mouse genetics and how they are integrated into an understanding of human Mg2+ physiology.
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Affiliation(s)
- Aubrey R Morrison
- Division of Nephrology Department of Medicine and Developmental Biology Washington University School of Medicine, St Louis MO, 63110 USA
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24
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Gaggar P, Raju DSB, Tej MR, Pragna P. Late-Onset Bartter's Syndrome Type II with End-Stage Renal Disease Due to a Novel Mutation in KCNJ1 Gene in an Indian Adult Male - A Case Report. Indian J Nephrol 2023; 33:57-60. [PMID: 37197039 PMCID: PMC10185019 DOI: 10.4103/ijn.ijn_383_21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/06/2021] [Indexed: 11/04/2022] Open
Abstract
Mutations in ROMK1 potassium channel gene (KCNJ1) causes antenatal/neonatal Bartter's syndrome type II, which presents with renal salt wasting, hypokalemic metabolic alkalosis, secondary hyperaldosteronism, hypercalciuria, and nephrocalcinosis. We herein describe a case of late-onset Bartter's syndrome type II with progressive renal failure requiring renal replacement therapy secondary to a novel homozygous missense mutation in Exon 2 of KCNJ1 gene (c.500G>A). With this case, we aim to highlight the need for a high index of suspicion and the role of genetic evaluation to diagnose clinically unclassified cases of nephrocalcinosis with renal electrolyte abnormalities more so in late and atypical presentations.
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Affiliation(s)
- Payal Gaggar
- Department of Nephrology, Nizam’s Institute of Medical Sciences, Punjagutta, Hyderabad, Telangana, India
| | - D Sree Bhushan Raju
- Department of Nephrology, Nizam’s Institute of Medical Sciences, Punjagutta, Hyderabad, Telangana, India
| | - M Ravi Tej
- Department of Nephrology, Nizam’s Institute of Medical Sciences, Punjagutta, Hyderabad, Telangana, India
| | - P Pragna
- Department of Nephrology, Nizam’s Institute of Medical Sciences, Punjagutta, Hyderabad, Telangana, India
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25
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Inverse Salt Sensitivity of Blood Pressure Is Associated with an Increased Renin-Angiotensin System Activity. Biomedicines 2022; 10:biomedicines10112811. [PMID: 36359330 PMCID: PMC9687845 DOI: 10.3390/biomedicines10112811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022] Open
Abstract
High and low sodium diets are associated with increased blood pressure and cardiovascular morbidity and mortality. The paradoxical response of elevated BP in low salt diets, aka inverse salt sensitivity (ISS), is an understudied vulnerable 11% of the adult population with yet undiscovered etiology. A linear relationship between the number of single nucleotide polymorphisms (SNPs) in the dopamine D2 receptor (DRD2, rs6276 and 6277), and the sodium myo-inositol cotransporter 2 (SLC5A11, rs11074656), as well as decreased expression of these two genes in urine-derived renal proximal tubule cells (uRPTCs) isolated from clinical study participants suggest involvement of these cells in ISS. Insight into this newly discovered paradoxical response to sodium is found by incubating cells in low sodium (LS) conditions that unveil cell physiologic differences that are then reversed by mir-485-5p miRNA blocker transfection and bypassing the genetic defect by DRD2 re-expression. The renin-angiotensin system (RAS) is an important counter-regulatory mechanism to prevent hyponatremia under LS conditions. Oversensitive RAS under LS conditions could partially explain the increased mortality in ISS. Angiotensin-II (AngII, 10 nmol/L) increased sodium transport in uRPTCs to a greater extent in individuals with ISS than SR. Downstream signaling of AngII is verified by identifying lowered expression of nuclear factor erythroid 2-related factor 2 (NRF2), CCCTC-binding factor (CTCF), and manganese-dependent mitochondrial superoxide dismutase (SOD2) only in ISS-derived uRPTCs and not SR-derived uRPTCs when incubated in LS conditions. We conclude that DRD2 and SLC5A11 variants in ISS may cause an increased low sodium sensitivity to AngII and renal sodium reabsorption which can contribute to inverse salt-sensitive hypertension.
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26
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Neumann C, Rosenbæk LL, Flygaard RK, Habeck M, Karlsen JL, Wang Y, Lindorff‐Larsen K, Gad HH, Hartmann R, Lyons JA, Fenton RA, Nissen P. Cryo-EM structure of the human NKCC1 transporter reveals mechanisms of ion coupling and specificity. EMBO J 2022; 41:e110169. [PMID: 36239040 PMCID: PMC9713717 DOI: 10.15252/embj.2021110169] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 09/20/2022] [Accepted: 09/22/2022] [Indexed: 12/03/2022] Open
Abstract
The sodium-potassium-chloride transporter NKCC1 of the SLC12 family performs Na+ -dependent Cl- - and K+ -ion uptake across plasma membranes. NKCC1 is important for regulating cell volume, hearing, blood pressure, and regulation of hyperpolarizing GABAergic and glycinergic signaling in the central nervous system. Here, we present a 2.6 Å resolution cryo-electron microscopy structure of human NKCC1 in the substrate-loaded (Na+ , K+ , and 2 Cl- ) and occluded, inward-facing state that has also been observed for the SLC6-type transporters MhsT and LeuT. Cl- binding at the Cl1 site together with the nearby K+ ion provides a crucial bridge between the LeuT-fold scaffold and bundle domains. Cl- -ion binding at the Cl2 site seems to undertake a structural role similar to conserved glutamate of SLC6 transporters and may allow for Cl- -sensitive regulation of transport. Supported by functional studies in mammalian cells and computational simulations, we describe a putative Na+ release pathway along transmembrane helix 5 coupled to the Cl2 site. The results provide insight into the structure-function relationship of NKCC1 with broader implications for other SLC12 family members.
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Affiliation(s)
- Caroline Neumann
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | | | - Rasmus Kock Flygaard
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Michael Habeck
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | | | - Yong Wang
- Linderstrøm‐Lang Centre for Protein Science, Department of BiologyUniversity of CopenhagenCopenhagenDenmark,Shanghai Institute for Advanced Study, Institute of Quantitative Biology, College of Life SciencesZhejiang UniversityHangzhouChina
| | - Kresten Lindorff‐Larsen
- Linderstrøm‐Lang Centre for Protein Science, Department of BiologyUniversity of CopenhagenCopenhagenDenmark
| | - Hans Henrik Gad
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Rune Hartmann
- Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
| | - Joseph Anthony Lyons
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark,Interdisciplinary Nanoscience Center (iNANO)Aarhus UniversityAarhusDenmark
| | | | - Poul Nissen
- Danish Research Institute of Translational Neuroscience—DANDRITENordic EMBL Partnership for Molecular MedicineAarhusDenmark,Department of Molecular Biology and GeneticsAarhus UniversityAarhusDenmark
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27
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Jurynec MJ, Gavile CM, Honeggar M, Ma Y, Veerabhadraiah SR, Novak KA, Hoshijima K, Kazmers NH, Grunwald DJ. NOD/RIPK2 signalling pathway contributes to osteoarthritis susceptibility. Ann Rheum Dis 2022; 81:1465-1473. [PMID: 35732460 PMCID: PMC9474725 DOI: 10.1136/annrheumdis-2022-222497] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 06/07/2022] [Indexed: 12/21/2022]
Abstract
OBJECTIVES How inflammatory signalling contributes to osteoarthritis (OA) susceptibility is undetermined. An allele encoding a hyperactive form of the Receptor Interacting Protein Kinase 2 (RIPK2) proinflammatory signalling intermediate has been associated with familial OA. To test whether altered nucleotide-binding oligomerisation domain (NOD)/RIPK2 pathway activity causes heightened OA susceptibility, we investigated whether variants affecting additional pathway components are associated with familial OA. To determine whether the Ripk2104Asp disease allele is sufficient to account for the familial phenotype, we determined the effect of the allele on mice. METHODS Genomic analysis of 150 independent families with dominant inheritance of OA affecting diverse joints was used to identify coding variants that segregated strictly with occurrence of OA. Genome editing was used to introduce the OA-associated RIPK2 (p.Asn104Asp) allele into the genome of inbred mice. The consequences of the Ripk2104Asp disease allele on physiology and OA susceptibility in mice were measured by histology, immunohistochemistry, serum cytokine levels and gene expression. RESULTS We identified six novel variants affecting components of the NOD/RIPK2 inflammatory signalling pathway that are associated with familial OA affecting the hand, shoulder or foot. The Ripk2104Asp allele acts dominantly to alter basal physiology and response to trauma in the mouse knee. Whereas the knees of uninjured Ripk2Asp104 mice appear normal histologically, the joints exhibit a set of marked gene expression changes reminiscent of overt OA. Although the Ripk2104Asp mice lack evidence of chronically elevated systemic inflammation, they do exhibit significantly increased susceptibility to post-traumatic OA (PTOA). CONCLUSIONS Two types of data support the hypothesis that altered NOD/RIPK2 signalling confers susceptibility to OA.
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Affiliation(s)
- Michael J Jurynec
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
- Department of Human Genetics, University of Utah Health, Salt Lake City, Utah, USA
| | - Catherine M Gavile
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - Matthew Honeggar
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - Ying Ma
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | | | - Kendra A Novak
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - Kazuyuki Hoshijima
- Department of Human Genetics, University of Utah Health, Salt Lake City, Utah, USA
| | - Nikolas H Kazmers
- Department of Orthopaedics, University of Utah Health, Salt Lake City, Utah, USA
| | - David J Grunwald
- Department of Human Genetics, University of Utah Health, Salt Lake City, Utah, USA
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28
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The Post-Translational Modification Networking in WNK-Centric Hypertension Regulation and Electrolyte Homeostasis. Biomedicines 2022; 10:biomedicines10092169. [PMID: 36140271 PMCID: PMC9496095 DOI: 10.3390/biomedicines10092169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/26/2022] [Accepted: 08/27/2022] [Indexed: 11/17/2022] Open
Abstract
The with-no-lysine (WNK) kinase family, comprising four serine-threonine protein kinases (WNK1-4), were first linked to hypertension due to their mutations in association with pseudohypoaldosteronism type II (PHAII). WNK kinases regulate crucial blood pressure regulators, SPAK/OSR1, to mediate the post-translational modifications (PTMs) of their downstream ion channel substrates, such as sodium chloride co-transporter (NCC), epithelial sodium chloride (ENaC), renal outer medullary potassium channel (ROMK), and Na/K/2Cl co-transporters (NKCCs). In this review, we summarize the molecular pathways dysregulating the WNKs and their downstream target renal ion transporters. We summarize each of the genetic variants of WNK kinases and the small molecule inhibitors that have been discovered to regulate blood pressure via WNK-triggered PTM cascades.
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29
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Rossanti R, Horinouchi T, Sakakibara N, Yamamura T, Nagano C, Ishiko S, Aoto Y, Kondo A, Nagai S, Awano H, Nagase H, Matsuo M, Iijima K, Nozu K. Detecting pathogenic deep intronic variants in Gitelman syndrome. Am J Med Genet A 2022; 188:2576-2583. [PMID: 35785516 DOI: 10.1002/ajmg.a.62885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 05/17/2022] [Accepted: 05/30/2022] [Indexed: 01/24/2023]
Abstract
Gitelman syndrome (GS) is a rare, autosomal recessive, salt-losing tubulopathy caused by loss of function in the SLC12A3 gene (NM_000339.2), which encodes the natrium chloride cotransporter. The detection of homozygous or compound heterozygous SLC12A3 variants is expected in GS, but 18%-40% of patients with clinical GS carry only one mutant allele. Previous reports identified some pathogenic deep intronic variants in SLC12A3. Here, we report the screening of SLC12A3 deep intronic variants in 13 patients with suspected GS carrying one mutated SLC12A3 allele. Variant screening used the HaloPlex Target Enrichment System Kit capturing whole introns and the promotor region of SLC12A3, followed by SureCall variant analysis. Rare intronic variants (<1% frequency) were identified, and pathogenicity evaluated by the minigene system. Deep intronic variant screening detected seven rare SLC12A3 variants from six patients. Only one variant showed pathogenicity in the minigene system (c.602-16G>A, intron 4) through activation of a cryptic acceptor site. No variants were detected in the promotor region. Deep intronic screening identified only one pathogenic variant in patients with suspected GS carrying monoallelic SLC12A3 variants. Our results suggest that deep intronic variants partially explain the cause of monoallelic variants in patients with GS.
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Affiliation(s)
- Rini Rossanti
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan.,Department of Child Health, Nephrology Division, Dr. Hasan Sadikin General Hospital/Faculty of Medicine, Universitas Padjadjaran, Bandung, Indonesia
| | - Tomoko Horinouchi
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Nana Sakakibara
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Tomohiko Yamamura
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - China Nagano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Shinya Ishiko
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Yuya Aoto
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Atsushi Kondo
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Sadayuki Nagai
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroyuki Awano
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hiroaki Nagase
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masafumi Matsuo
- Research Center for Locomotion Biology, Kobe Gakuin University, Kobe, Hyogo, Japan
| | - Kazumoto Iijima
- Hyogo Prefectural Kobe Children's Hospital, Kobe, Hyogo, Japan.,Department of Advanced Pediatric Medicine, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan
| | - Kandai Nozu
- Department of Pediatrics, Kobe University Graduate School of Medicine, Kobe, Japan
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30
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Xin Q, Liu Q, Liu Z, Shi X, Liu X, Zhang R, Hong Y, Zhao X, Shao L. Twelve exonic variants in the SLC12A1 and CLCNKB genes alter RNA splicing in a minigene assay. Front Genet 2022; 13:961384. [PMID: 36092934 PMCID: PMC9452827 DOI: 10.3389/fgene.2022.961384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Bartter syndrome (BS) is a rare renal tubular disease caused by gene variants in SLC12A1, KCNJ1, CLCNKA, CLCNKB, BSND or MAGED2 genes. There is growing evidence that many exonic mutations can affect the pre-mRNA normal splicing and induce exon skipping by altering various splicing regulatory signals. Therefore, the aim of this study was to gain new insights into the consequences of exonic mutations associated with BS on pre-mRNA splicing.Methods: We analyzed all the missense, nonsense and synonymous variants described in six pathogenic genes by bioinformatics programs and identified candidate mutations that may promote exon skipping through a minigene system.Results: Results of the study showed that 12 of 14 candidate variants distributed in SLC12A1 (c.728G>A, C.735C>G, c.904C>T, c.905G>A, c.1304C>T, c.1493C>T, c.2221A>T) and CLCNKB (c.226C>T, c.228A>C, c.229G>A, c.229G>C, c.1979C>A) were identified to induce splicing alterations. These variants may not only disrupt exonic splicing enhancers (ESEs) but also generate new exonic splicing silencers (ESSs), or disturb the classic splicing sites.Conclusion: To our knowledge, this is a comprehensive study regarding alterations in pre-mRNA of exonic variants in BS pathogenic genes. Our results reinforce the necessity of assessing the consequences of exonic variants at the mRNA level.
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Affiliation(s)
- Qing Xin
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Qihua Liu
- Department of Material Supply Management, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Zhiying Liu
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Xiaomeng Shi
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Xuyan Liu
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Ruixiao Zhang
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
| | - Yefeng Hong
- Department of Cardiology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiangzhong Zhao
- Medical Research Center, The Affiliated Hospital of Qingdao University, Qingdao, China
- *Correspondence: Xiangzhong Zhao, ; Leping Shao,
| | - Leping Shao
- Department of Nephrology, the Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, China
- *Correspondence: Xiangzhong Zhao, ; Leping Shao,
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31
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Inverse Salt Sensitivity of Blood Pressure: Mechanisms and Potential Relevance for Prevention of Cardiovascular Disease. Curr Hypertens Rep 2022; 24:361-374. [PMID: 35708819 DOI: 10.1007/s11906-022-01201-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/07/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE OF REVIEW To review the etiology of inverse salt sensitivity of blood pressure (BP). RECENT FINDINGS Both high and low sodium (Na+) intake can be associated with increased BP and cardiovascular morbidity and mortality. However, little is known regarding the mechanisms involved in the increase in BP in response to low Na+ intake, a condition termed inverse salt sensitivity of BP, which affects approximately 15% of the adult population. The renal proximal tubule is important in regulating up to 70% of renal Na+ transport. The renin-angiotensin and renal dopaminergic systems play both synergistic and opposing roles in the regulation of Na+ transport in this nephron segment. Clinical studies have demonstrated that individuals express a "personal salt index" (PSI) that marks whether they are salt-resistant, salt-sensitive, or inverse salt-sensitive. Inverse salt sensitivity results in part from genetic polymorphisms in various Na+ regulatory genes leading to a decrease in natriuretic activity and an increase in renal tubular Na+ reabsorption leading to an increase in BP. This article reviews the potential mechanisms of a new pathophysiologic entity, inverse salt sensitivity of BP, which affects approximately 15% of the general adult population.
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Zhu Y, Pan H, Han Y, Li T, Liu K, Wang B. Novel missense variant of CIITA contributing to endometriosis. Reprod Biomed Online 2022; 45:544-551. [DOI: 10.1016/j.rbmo.2022.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Revised: 04/28/2022] [Accepted: 05/17/2022] [Indexed: 11/30/2022]
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Ravarotto V, Bertoldi G, Stefanelli LF, Gobbi L, Calò LA. Molecular aspects of the altered Angiotensin II signalling in Gitelman’s syndrome. Expert Opin Orphan Drugs 2022. [DOI: 10.1080/21678707.2022.2066996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Verdiana Ravarotto
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine (DIMED) University of Padova, Italy
| | - Giovanni Bertoldi
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine (DIMED) University of Padova, Italy
| | - Lucia Federica Stefanelli
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine (DIMED) University of Padova, Italy
| | - Laura Gobbi
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine (DIMED) University of Padova, Italy
| | - Lorenzo A. Calò
- Nephrology, Dialysis and Transplantation Unit, Department of Medicine (DIMED) University of Padova, Italy
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Tian M, Peng H, Bi X, Wang YQ, Zhang YZ, Wu Y, Zhang BR. Late-Onset Bartter Syndrome Type II Due to a Novel Compound Heterozygous Mutation in KCNJ1 Gene: A Case Report and Literature Review. Front Med (Lausanne) 2022; 9:862514. [PMID: 35463019 PMCID: PMC9021870 DOI: 10.3389/fmed.2022.862514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/14/2022] [Indexed: 11/16/2022] Open
Abstract
Background Bartter syndrome (BS) type II is a rare autosomal recessive renal tubular disorder caused by mutations in the KCNJ1 gene, which encodes the apical renal outer medullary potassium (ROMK) channel in the thick ascending limb (TAL) of Henle’s loop. BS type II is typically considered as a disorder of infancy and seldom seen in adults. Case Presentation A 34-year-old woman was admitted with generalized body numbness and hand convulsions, without growth retardation. Laboratory tests revealed hypokalemic metabolic alkalosis, hyperreninemic hyperaldosteronism, and nephrocalcinosis. She was misdiagnosed during the initial diagnosis process and was finally diagnosed with late-onset BS type II via genetic testing through next-generation sequencing combined with Sanger sequencing. A novel compound heterozygous p.Leu207Ile/p. Cys308Arg variant in exon 5 of the KCNJ1 gene from her parents was identified and speculated to be a potential pathogenic gene variation. Conclusion We report a case of late-onset BS type II with a novel compound heterozygous mutation in KCNJ1. Both variants are novel and have never been reported. Our report will have a significant impact on the diagnosis of BS in other patients without typical clinical presentations and emphasizes the importance of genetic investigation.
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Affiliation(s)
- Mi Tian
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Hui Peng
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Xin Bi
- Guangzhou KingMed Center for Clinical Laboratory Co, Ltd., Guangzhou, China
| | - Yan-Qiu Wang
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yong-Zhe Zhang
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yan Wu
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Bei-Ru Zhang
- Department of Nephrology, Shengjing Hospital of China Medical University, Shenyang, China
- *Correspondence: Bei-Ru Zhang,
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Affiliation(s)
- Daniel O'Meara
- From the Departments of Pediatrics (D.O.), Nephrology (L.S.), Adolescent Medicine (S.H.-M., J.A.), and Genetics (A.A.-E.-H.), Boston Children's Hospital, Boston
| | - Lea Sheward
- From the Departments of Pediatrics (D.O.), Nephrology (L.S.), Adolescent Medicine (S.H.-M., J.A.), and Genetics (A.A.-E.-H.), Boston Children's Hospital, Boston
| | - Sydney Hartman-Munick
- From the Departments of Pediatrics (D.O.), Nephrology (L.S.), Adolescent Medicine (S.H.-M., J.A.), and Genetics (A.A.-E.-H.), Boston Children's Hospital, Boston
| | - Jessica Addison
- From the Departments of Pediatrics (D.O.), Nephrology (L.S.), Adolescent Medicine (S.H.-M., J.A.), and Genetics (A.A.-E.-H.), Boston Children's Hospital, Boston
| | - Aya Abu-El-Haija
- From the Departments of Pediatrics (D.O.), Nephrology (L.S.), Adolescent Medicine (S.H.-M., J.A.), and Genetics (A.A.-E.-H.), Boston Children's Hospital, Boston
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Jiang L, Peng X, Zhao B, Zhang L, Xu L, Li X, Nie M, Chen L. Frequent SLC12A3 mutations in Chinese Gitelman syndrome patients: structure and function disorder. Endocr Connect 2022; 11:EC-21-0262.R2. [PMID: 34860177 PMCID: PMC8859957 DOI: 10.1530/ec-21-0262] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 12/03/2021] [Indexed: 11/08/2022]
Abstract
PURPOSES This study was conducted to identify the frequent mutations from reported Chinese Gitelman syndrome (GS) patients, to predict the three-dimensional structure change of human Na-Cl co-transporter (hNCC), and to test the activity of these mutations and some novel mutations in vitro and in vivo. METHODS SLC12A3 gene mutations in Chinese GS patients previously reported in the PubMed, China National Knowledge Infrastructure, and Wanfang database were summarized. Predicted configurations of wild type (WT) and mutant proteins were achieved using the I-TASSER workplace. Six missense mutations (T60M, L215F, D486N, N534K, Q617R, and R928C) were generated by site-directed mutagenesis. 22Na+ uptake experiment was carried out in the Xenopus laevisoocyte expression system. In the study, 35 GS patients and 20 healthy volunteers underwent the thiazide test. RESULTS T60M, T163M, D486N, R913Q, R928C, and R959frameshift were frequent SLC12A3 gene mutations (mutated frequency >3%) in 310 Chinese GS families. The protein's three-dimensional structure was predicted to be altered in all mutations. Compared with WT hNCC, the thiazide-sensitive 22Na+ uptake was significantly diminished for all six mutations: T60M 22 ± 9.2%, R928C 29 ± 12%, L215F 38 ± 14%, N534K 41 ± 15.5%, Q617R 63 ± 22.1%, and D486N 77 ± 20.4%. In thiazide test, the net increase in chloride fractional excretion in 20 healthy controls was significantly higher than GS patients with or without T60M or D486N mutations. CONCLUSIONS Frequent mutations (T60M, D486N, and R928C) and novel mutations (L215F, N534K, and Q617R) lead to protein structure alternation and protein dysfunction verified by 22Na+ uptake experiment in vitro and thiazide test on the patients.
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Affiliation(s)
- Lanping Jiang
- Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Department of Nephrology & Key Laboratory of Nephrology, National Health Commission and Guangdong Province, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaoyan Peng
- Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Renal Division, Children’s Hospital Affiliated to Capital Institute of Pediatrics, Beijing, China
| | - Bingbin Zhao
- Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lei Zhang
- Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Lubin Xu
- Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Xuemei Li
- Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Min Nie
- Department of Endocrinology & Key Laboratory of Endocrinology, National Health and Family Planning Commission, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Correspondence should be addressed to L Chen or M Nie: or
| | - Limeng Chen
- Department of Nephrology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
- Correspondence should be addressed to L Chen or M Nie: or
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Delles C. Maternally Inherited Essential Hypertension: Adding Further Complexity to an Already Complex Condition. Am J Hypertens 2022; 35:16-18. [PMID: 34427578 DOI: 10.1093/ajh/hpab133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 12/11/2022] Open
Affiliation(s)
- Christian Delles
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
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Marcoux AA, Tremblay LE, Slimani S, Fiola MJ, Mac-Way F, Haydock L, Garneau AP, Isenring P. Anatomophysiology of the Henle's Loop: Emphasis on the Thick Ascending Limb. Compr Physiol 2021; 12:3119-3139. [PMID: 34964111 DOI: 10.1002/cphy.c210021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The loop of Henle plays a variety of important physiological roles through the concerted actions of ion transport systems in both its apical and basolateral membranes. It is involved most notably in extracellular fluid volume and blood pressure regulation as well as Ca2+ , Mg2+ , and acid-base homeostasis because of its ability to reclaim a large fraction of the ultrafiltered solute load. This nephron segment is also involved in urinary concentration by energizing several of the steps that are required to generate a gradient of increasing osmolality from cortex to medulla. Another important role of the loop of Henle is to sustain a process known as tubuloglomerular feedback through the presence of specialized renal tubular cells that lie next to the juxtaglomerular arterioles. This article aims at describing these physiological roles and at discussing a number of the molecular mechanisms involved. It will also report on novel findings and uncertainties regarding the realization of certain processes and on the pathophysiological consequences of perturbed salt handling by the thick ascending limb of the loop of Henle. Since its discovery 150 years ago, the loop of Henle has remained in the spotlight and is now generating further interest because of its role in the renal-sparing effect of SGLT2 inhibitors. © 2022 American Physiological Society. Compr Physiol 12:1-21, 2022.
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Affiliation(s)
- Andrée-Anne Marcoux
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Laurence E Tremblay
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Samira Slimani
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Marie-Jeanne Fiola
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Fabrice Mac-Way
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Ludwig Haydock
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
| | - Alexandre P Garneau
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada.,Cardiometabolic Axis, School of Kinesiology and Physical Activity Sciences, University of Montréal, Montréal, QC, Canada
| | - Paul Isenring
- Nephrology Research Group, Department of Medicine, Laval University, Québec, QC, Canada
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Yamazaki O, Yamashita M, Li J, Ochiai-Homma F, Yoshida T, Hirahashi J, Furukawa T, Kozuma K, Fujigaki Y, Seki G, Hayashi M, Shibata S. A novel I551F variant of the Na +/HCO 3- cotransporter NBCe1-A shows reduced cell surface expression, resulting in diminished transport activity. Am J Physiol Renal Physiol 2021; 321:F771-F784. [PMID: 34719949 DOI: 10.1152/ajprenal.00584.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Homozygous mutations in SLC4A4, which encodes the electrogenic Na+/[Formula: see text] cotransporter (NBCe1), cause proximal renal tubular acidosis associated with extrarenal symptoms. Although 17` mutated sites in SLC4A4 have thus far been identified among patients with proximal renal tubular acidosis, the physiological significance of other nonsynonymous single-nucleotide variants (SNVs) remains largely undetermined. Here, we investigated the functional properties of SNVs in NBCe1. From the National Center for Biotechnology Information dbSNP database, we identified 13 SNVs that have not previously been characterized in the highly conserved, transmembrane domains of NBCe1-A. Immunocytochemical analysis revealed that the I551F variant was present predominantly in the cytoplasm in human embryonic kidney (HEK)-293 cells, whereas all other SNVs did not show as dramatic a change in subcellular distribution. Western blot analysis in HEK-293 cells demonstrated that the I551F variant showed impaired glycosylation and a 69% reduction in cell surface levels. To determine the role of I551 in more detail, we examined the significance of various artificial mutants in both nonpolarized HEK-293 cells and polarized Madin-Darby canine kidney cells, which indicated that only I551F substitution resulted in cytoplasmic retention. Moreover, functional analysis using Xenopus oocytes demonstrated that the I551F variant had a significantly reduced activity corresponding to 39% of that of the wild-type, whereas any other SNVs and artificial I551 mutants did not show significant changes in activity. Finally, immunofluorescence experiments in HEK-293 cells indicated that the I551F variant retained wild-type NBCe1-A in the cytoplasm. These data demonstrate that the I551F variant of NBCe1-A shows impaired transport activity predominantly through cytoplasmic retention and suggest that the variant can have a dominant negative effect by forming complexes with wild-type NBCe1-A.NEW & NOTEWORTHY Electrogenic Na+/[Formula: see text] cotransporter 1-A (NBCe1-A) in the proximal tubule regulates the acid/base balance and fluid volume homeostasis. From the National Center for Biotechnology Information dbSNP database, we identified the I551F variant of NBCe1-A, which showed reduced glycosylation, cell surface expression, and transport activity. We also found that the I551F variant can exert a dominant negative effect on wild-type NBCe1-A, suggesting its physiological significance.
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Affiliation(s)
- Osamu Yamazaki
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan.,Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Maho Yamashita
- Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Jinping Li
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Fumika Ochiai-Homma
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Tadashi Yoshida
- Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Junichi Hirahashi
- Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan
| | - Taiji Furukawa
- Department of Laboratory Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Ken Kozuma
- Division of Cardiology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | - Yoshihide Fujigaki
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
| | | | - Matsuhiko Hayashi
- Department of General Medicine, Keio University School of Medicine, Tokyo, Japan.,Apheresis and Dialysis Center, Keio University School of Medicine, Tokyo, Japan.,Kawakita General Hospital, Center for Clinical Education, Tokyo, Japan
| | - Shigeru Shibata
- Division of Nephrology, Department of Internal Medicine, Teikyo University School of Medicine, Tokyo, Japan
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Nuñez-Gonzalez L, Carrera N, Garcia-Gonzalez MA. Molecular Basis, Diagnostic Challenges and Therapeutic Approaches of Bartter and Gitelman Syndromes: A Primer for Clinicians. Int J Mol Sci 2021; 22:11414. [PMID: 34768847 PMCID: PMC8584233 DOI: 10.3390/ijms222111414] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 12/18/2022] Open
Abstract
Gitelman and Bartter syndromes are rare inherited diseases that belong to the category of renal tubulopathies. The genes associated with these pathologies encode electrolyte transport proteins located in the nephron, particularly in the Distal Convoluted Tubule and Ascending Loop of Henle. Therefore, both syndromes are characterized by alterations in the secretion and reabsorption processes that occur in these regions. Patients suffer from deficiencies in the concentration of electrolytes in the blood and urine, which leads to different systemic consequences related to these salt-wasting processes. The main clinical features of both syndromes are hypokalemia, hypochloremia, metabolic alkalosis, hyperreninemia and hyperaldosteronism. Despite having a different molecular etiology, Gitelman and Bartter syndromes share a relevant number of clinical symptoms, and they have similar therapeutic approaches. The main basis of their treatment consists of electrolytes supplements accompanied by dietary changes. Specifically for Bartter syndrome, the use of non-steroidal anti-inflammatory drugs is also strongly supported. This review aims to address the latest diagnostic challenges and therapeutic approaches, as well as relevant recent research on the biology of the proteins involved in disease. Finally, we highlight several objectives to continue advancing in the characterization of both etiologies.
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Affiliation(s)
- Laura Nuñez-Gonzalez
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
| | - Noa Carrera
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- RedInRen (Red en Investigación Renal) RETIC (Redes Temáticas de Investigación Cooperativa en Salud), ISCIII (Instituto de Salud Carlos III), 28029 Madrid, Spain
| | - Miguel A. Garcia-Gonzalez
- Grupo de Xenetica e Bioloxia do Desenvolvemento das Enfermidades Renais, Laboratorio de Nefroloxia (No. 11), Instituto de Investigacion Sanitaria de Santiago (IDIS), Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain;
- Grupo de Medicina Xenomica, Complexo Hospitalario de Santiago de Compostela (CHUS), 15706 Santiago de Compostela, Spain
- RedInRen (Red en Investigación Renal) RETIC (Redes Temáticas de Investigación Cooperativa en Salud), ISCIII (Instituto de Salud Carlos III), 28029 Madrid, Spain
- Fundación Pública Galega de Medicina Xenomica—SERGAS, Complexo Hospitalario de Santiago de Compotela (CHUS), 15706 Santiago de Compostela, Spain
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Portioli C, Ruiz Munevar MJ, De Vivo M, Cancedda L. Cation-coupled chloride cotransporters: chemical insights and disease implications. TRENDS IN CHEMISTRY 2021; 3:832-849. [PMID: 34604727 PMCID: PMC8461084 DOI: 10.1016/j.trechm.2021.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Cation-coupled chloride cotransporters (CCCs) modulate the transport of sodium and/or potassium cations coupled with chloride anions across the cell membrane. CCCs thus help regulate intracellular ionic concentration and consequent cell volume homeostasis. This has been largely exploited in the past to develop diuretic drugs that act on CCCs expressed in the kidney. However, a growing wealth of evidence has demonstrated that CCCs are also critically involved in a great variety of other pathologies, motivating most recent drug discovery programs targeting CCCs. Here, we examine the structure–function relationship of CCCs. By linking recent high-resolution cryogenic electron microscopy (cryo-EM) data with older biochemical/functional studies on CCCs, we discuss the mechanistic insights and opportunities to design selective CCC modulators to treat diverse pathologies. The structural topology and function of all cation-coupled chloride cotransporters (CCCs) have been continuously investigated over the past 40 years, with great progress also thanks to the recent cryogenic electron microscopy (cryo-EM) resolution of the structures of five CCCs. In particular, such studies have clarified the structure–function relationship for the Na-K-Cl cotransporter NKCC1 and K-Cl cotransporters KCC1–4. The constantly growing evidence of the crucial involvement of CCCs in physiological and various pathological conditions, as well as the evidence of their wide expression in diverse body tissues, has promoted CCCs as targets for the discovery and development of new, safer, and more selective/effective drugs for a plethora of pathologies. Post-translational modification anchor points on the structure of CCCs may offer alternative strategies for small molecule drug discovery.
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Affiliation(s)
- Corinne Portioli
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy.,Laboratory of Molecular Modeling and Drug Discovery, IIT, Via Morego, 30 16163 Genoa, Italy
| | | | - Marco De Vivo
- Laboratory of Molecular Modeling and Drug Discovery, IIT, Via Morego, 30 16163 Genoa, Italy
| | - Laura Cancedda
- Brain Development and Disease Laboratory, Istituto Italiano di Tecnologia (IIT), Via Morego 30, 16163 Genoa, Italy.,Dulbecco Telethon Institute, Via Varese 16b, 00185 Rome, Italy
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Tang D, Xu J, Li Y, Zhao P, Kong X, Hu H, Liang S, Tang C, Liu Z. Molecular mechanisms of centipede toxin SsTx-4 inhibition of inwardly rectifying potassium channels. J Biol Chem 2021; 297:101076. [PMID: 34391777 PMCID: PMC8413892 DOI: 10.1016/j.jbc.2021.101076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/05/2021] [Accepted: 08/11/2021] [Indexed: 11/29/2022] Open
Abstract
Inwardly rectifying potassium channels (Kirs) are important drug targets, with antagonists for the Kir1.1, Kir4.1, and pancreatic Kir6.2/SUR1 channels being potential drug candidates for treating hypertension, depression, and diabetes, respectively. However, few peptide toxins acting on Kirs are identified and their interacting mechanisms remain largely elusive yet. Herein, we showed that the centipede toxin SsTx-4 potently inhibited the Kir1.1, Kir4.1, and Kir6.2/SUR1 channels with nanomolar to submicromolar affinities and intensively studied the molecular bases for toxin–channel interactions using patch-clamp analysis and site-directed mutations. Other Kirs including Kir2.1 to 2.4, Kir4.2, and Kir7.1 were resistant to SsTx-4 treatment. Moreover, SsTx-4 inhibited the inward and outward currents of Kirs with different potencies, possibly caused by a K+ “knock-off” effect, suggesting the toxin functions as an out pore blocker physically occluding the K+-conducting pathway. This conclusion was further supported by a mutation analysis showing that M137 located in the outer vestibule of the Kir6.2/ΔC26 channel was the key residue mediating interaction with SsTx-4. On the other hand, the molecular determinants within SsTx-4 for binding these Kir channels only partially overlapped, with K13 and F44 being the common key residues. Most importantly, K11A, P15A, and Y16A mutant toxins showed improved affinity and/or selectivity toward Kir6.2, while R12A mutant toxin had increased affinity for Kir4.1. To our knowledge, SsTx-4 is the first characterized peptide toxin with Kir4.1 inhibitory activity. This study provides useful insights for engineering a Kir6.2/SUR1 channel–specific antagonist based on the SsTx-4 template molecule and may be useful in developing new antidiabetic drugs.
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Affiliation(s)
- Dongfang Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China; College of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, Hunan, China
| | - Jiahui Xu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Yinping Li
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Piao Zhao
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Xiangjin Kong
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Haoliang Hu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China.
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China.
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Yan MT, Yang SS, Tseng MH, Cheng CJ, Tsai JD, Sung CC, Hsu YJ, Lin SH. Allele-specific RT-PCR for the rapid detection of recurrent SLC12A3 mutations for Gitelman syndrome. NPJ Genom Med 2021; 6:68. [PMID: 34389731 PMCID: PMC8363728 DOI: 10.1038/s41525-021-00230-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 07/23/2021] [Indexed: 12/20/2022] Open
Abstract
Recurrent mutations in the SLC12A3 gene responsible for autosomal recessive Gitelman syndrome (GS) are frequently reported, but the exact prevalence is unknown. The rapid detection of recurrent SLC12A3 mutations may help in the early diagnosis of GS. This study was aimed to investigate the prevalence of recurrent SLC12A3 mutations in a Taiwan cohort of GS families and develop a simple and rapid method to detect recurrent SLC12A3 mutations. One hundred and thirty independent Taiwan families with genetically confirmed GS were consecutively enrolled to define recurrent SLC12A3 mutations and determine their prevalence. Using TaqMan probe-based real-time polymerase chain reaction, we designed a mutation detection plate with all recurrent mutations. We validated this mutation detection plate and tested its feasibility in newly diagnosed GS patients. A total of 57 mutations in the SLC12A3 gene were identified and 22 including 2 deep intronic mutations were recurrent mutations consisting of 87.1% (242/278, 18 triple) of all allelic mutations. The recurrent mutation-based TaqMan assays were fully validated with excellent sensitivity and specificity in genetically diagnosed GS patients and healthy subjects. In clinical validation, recurrent mutations were recognized in 92.0% of allelic mutations from 12 GS patients within 4 h and all were confirmed by direct sequencing. Recurrent SLC12A3 mutations are very common in Taiwan GS patients and can be rapidly identified by this recurrent mutation-based SLC12A3 mutation plate.
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Affiliation(s)
- Ming-Tso Yan
- Division of Nephrology, Department of Medicine, Cathay General Hospital, School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan.,Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Sung-Sen Yang
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Min-Hua Tseng
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Pediatric Nephrology, Department of Pediatrics, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chih-Jen Cheng
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Jeng-Daw Tsai
- Division of Nephrology, Department of Pediatrics, MacKay Memorial Hospital, Taipei, Taiwan
| | - Chih-Chien Sung
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Yu-Juei Hsu
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan.,Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan
| | - Shih-Hua Lin
- Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan. .,Division of Nephrology, Department of Medicine, Tri-Service General Hospital, Taipei, Taiwan.
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Examination of the predicted prevalence of Gitelman syndrome by ethnicity based on genome databases. Sci Rep 2021; 11:16099. [PMID: 34373523 PMCID: PMC8352941 DOI: 10.1038/s41598-021-95521-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 07/27/2021] [Indexed: 01/19/2023] Open
Abstract
Gitelman syndrome is an autosomal recessive inherited salt-losing tubulopathy. It has a prevalence of around 1 in 40,000 people, and heterozygous carriers are estimated at approximately 1%, although the exact prevalence is unknown. We estimated the predicted prevalence of Gitelman syndrome based on multiple genome databases, HGVD and jMorp for the Japanese population and gnomAD for other ethnicities, and included all 274 pathogenic missense or nonsense variants registered in HGMD Professional. The frequencies of all these alleles were summed to calculate the total variant allele frequency in SLC12A3. The carrier frequency and the disease prevalence were assumed to be twice and the square of the total allele frequency, respectively, according to the Hardy–Weinberg principle. In the Japanese population, the total carrier frequencies were 0.0948 (9.5%) and 0.0868 (8.7%) and the calculated prevalence was 0.00225 (2.3 in 1000 people) and 0.00188 (1.9 in 1000 people) in HGVD and jMorp, respectively. Other ethnicities showed a prevalence varying from 0.000012 to 0.00083. These findings indicate that the prevalence of Gitelman syndrome in the Japanese population is higher than expected and that some other ethnicities also have a higher prevalence than has previously been considered.
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Boder P, Mary S, Mark PB, Leiper J, Dominiczak AF, Padmanabhan S, Rampoldi L, Delles C. Mechanistic interactions of uromodulin with the thick ascending limb: perspectives in physiology and hypertension. J Hypertens 2021; 39:1490-1504. [PMID: 34187999 PMCID: PMC7611110 DOI: 10.1097/hjh.0000000000002861] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypertension is a significant risk factor for cardiovascular disease and mortality worldwide. The kidney is a major regulator of blood pressure and electrolyte homeostasis, with monogenic disorders indicating a link between abnormal ion transport and salt-sensitive hypertension. However, the association between salt and hypertension remains controversial. Thus, there is continued interest in deciphering the molecular mechanisms behind these processes. Uromodulin (UMOD) is the most abundant protein in the normal urine and is primarily synthesized by the thick ascending limb epithelial cells of the kidney. Genome-wide association studies have linked common UMOD variants with kidney function, susceptibility to chronic kidney disease and hypertension independent of renal excretory function. This review will discuss and provide predictions on the role of the UMOD protein in renal ion transport and hypertension based on current observational, biochemical, genetic, pharmacological and clinical evidence.
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Affiliation(s)
- Philipp Boder
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sheon Mary
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Patrick B. Mark
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - James Leiper
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anna F. Dominiczak
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sandosh Padmanabhan
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Luca Rampoldi
- Molecular Genetics of Renal Disorders Unit, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Christian Delles
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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46
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Honda K, Kuriyama S, Ichida K, Nakano T, Sugano N, Yokoo T. Association between polymorphism at IGF-1 rs35767 gene locus and long-term decline in renal function: a Japanese retrospective longitudinal cohort study. BMC Nephrol 2021; 22:207. [PMID: 34078313 PMCID: PMC8173978 DOI: 10.1186/s12882-021-02408-9] [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: 01/13/2021] [Accepted: 05/13/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Insulin-like growth factor-1 (IGF-1) acts on glucose and protein metabolism and human growth and also influences blood pressure and renal function. This study investigated whether the single-nucleotide polymorphism of IGF-1, rs35767, plays a role in metabolic syndrome indicators, including blood pressure, glucose metabolism, uric acid levels, and renal function. METHODS In this retrospective longitudinal cohort study, blood samples from 1506 Japanese individuals were collected and used for genotyping for variant rs35767: T > C in the IGF-1 upstream promoter. Data were analyzed to identify associations between IGF-1 genotypes and patient biochemical parameters, including the components of metabolic syndrome and the long-term change in renal function. RESULTS The cohort rs35767 genotypes included 650 CC carriers (43.2%), 687 TC carriers (45.6%), and 169 TT carriers (11.2%). Multiple regression analysis revealed no association between IGF-1 genotype and blood pressure, glycated hemoglobin level, and serum uric acid level. However, in females, blood pressure was negatively correlated with the TT genotype. Longitudinal observation revealed that the decline in eGFR over 10 years was greater in TT (- 18.51 ± 1.04 mL/min/1.73m2) than in CC carriers (- 16.38 ± 0.52 mL/min/1.73m2; P < 0.05). CONCLUSION The present study suggests that renal function declines faster in individuals with the TT genotype at the IGF-1 rs35767 locus than in those with the CC genotype, suggesting that the TT genotype is associated with the long-term chronological decline in renal function.
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Affiliation(s)
- Kosuke Honda
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.
| | - Satoru Kuriyama
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan.,Nephrology & Hypertension Research Unit, Miho Clinic, Tokyo, Japan
| | - Kimiyoshi Ichida
- Department of Pathophysiology, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan
| | - Tomoko Nakano
- Health Management Center of the Tokyo Regional Taxation Bureau Clinic, Tokyo, Japan
| | - Naoki Sugano
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Takashi Yokoo
- Division of Nephrology and Hypertension, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
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47
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Jiang J, Ding FX, Zhou X, Bateman TJ, Dong S, Gu X, Keh deJesus R, Pio B, Tang H, Chobanian HR, Levorse D, Hu M, Thomas-Fowlkes B, Margulis M, Koehler M, Weinglass A, Gibson J, Houle K, Yudkovitz J, Hampton C, Pai LY, Samuel K, Cutarelli T, Sullivan K, Parmee ER, Davies I, Pasternak A. Discovery of MK-8153, a Potent and Selective ROMK Inhibitor and Novel Diuretic/Natriuretic. J Med Chem 2021; 64:7691-7701. [PMID: 34038119 DOI: 10.1021/acs.jmedchem.1c00406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A renal outer medullary potassium channel (ROMK, Kir1.1) is a putative drug target for a novel class of diuretics with potential for treating hypertension and heart failure. Our first disclosed clinical ROMK compound, 2 (MK-7145), demonstrated robust diuresis, natriuresis, and blood pressure lowering in preclinical models, with reduced urinary potassium excretion compared to the standard of care diuretics. However, 2 projected to a short human half-life (∼5 h) that could necessitate more frequent than once a day dosing. In addition, a short half-life would confer a high peak-to-trough ratio which could evoke an excessive peak diuretic effect, a common liability associated with loop diuretics such as furosemide. This report describes the discovery of a new ROMK inhibitor 22e (MK-8153), with a longer projected human half-life (∼14 h), which should lead to a reduced peak-to-trough ratio, potentially extrapolating to more extended and better tolerated diuretic effects.
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Affiliation(s)
- Jinlong Jiang
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Fa-Xiang Ding
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Xiaoyan Zhou
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Thomas J Bateman
- Pharmacokinetics Pharmacodynamics and Drug Metabolism, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Shuzhi Dong
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Xin Gu
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Reynalda Keh deJesus
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Barbara Pio
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Haifeng Tang
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Harry R Chobanian
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Dorothy Levorse
- Discovery and Preclinical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Mengwei Hu
- Discovery and Preclinical Sciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Brande Thomas-Fowlkes
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Michael Margulis
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Martin Koehler
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Adam Weinglass
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Jack Gibson
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Kevin Houle
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Joel Yudkovitz
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Caryn Hampton
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Lee-Yuh Pai
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Koppara Samuel
- Pharmacokinetics Pharmacodynamics and Drug Metabolism, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Timothy Cutarelli
- Discovery Process Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Kathleen Sullivan
- Quantitative Biosciences, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Emma R Parmee
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Ian Davies
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Alexander Pasternak
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
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48
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Mansilla MA, Sompallae RR, Nishimura CJ, Kwitek AE, Kimble MJ, Freese ME, Campbell CA, Smith RJ, Thomas CP. Targeted broad-based genetic testing by next-generation sequencing informs diagnosis and facilitates management in patients with kidney diseases. Nephrol Dial Transplant 2021; 36:295-305. [PMID: 31738409 PMCID: PMC7834596 DOI: 10.1093/ndt/gfz173] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 07/23/2019] [Indexed: 12/15/2022] Open
Abstract
Background The clinical diagnosis of genetic renal diseases may be limited by the overlapping spectrum of manifestations between diseases or by the advancement of disease where clues to the original process are absent. The objective of this study was to determine whether genetic testing informs diagnosis and facilitates management of kidney disease patients. Methods We developed a comprehensive genetic testing panel (KidneySeq) to evaluate patients with various phenotypes including cystic diseases, congenital anomalies of the kidney and urinary tract (CAKUT), tubulointerstitial diseases, transport disorders and glomerular diseases. We evaluated this panel in 127 consecutive patients ranging in age from newborns to 81 years who had samples sent in for genetic testing. Results The performance of the sequencing pipeline for single-nucleotide variants was validated using CEPH (Centre de’Etude du Polymorphism) controls and for indels using Genome-in-a-Bottle. To test the reliability of the copy number variant (CNV) analysis, positive samples were re-sequenced and analyzed. For patient samples, a multidisciplinary review board interpreted genetic results in the context of clinical data. A genetic diagnosis was made in 54 (43%) patients and ranged from 54% for CAKUT, 53% for ciliopathies/tubulointerstitial diseases, 45% for transport disorders to 33% for glomerulopathies. Pathogenic and likely pathogenic variants included 46% missense, 11% nonsense, 6% splice site variants, 23% insertion–deletions and 14% CNVs. In 13 cases, the genetic result changed the clinical diagnosis. Conclusion Broad genetic testing should be considered in the evaluation of renal patients as it complements other tests and provides insight into the underlying disease and its management.
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Affiliation(s)
- M Adela Mansilla
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, IA, USA
| | | | - Carla J Nishimura
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, IA, USA
| | - Anne E Kwitek
- Physiology, Medical College of Wisconsin, Iowa City, IA, USA
| | - Mycah J Kimble
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, IA, USA
| | | | - Colleen A Campbell
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, IA, USA
| | - Richard J Smith
- Iowa Institute of Human Genetics, University of Iowa, Iowa City, IA, USA.,Internal Medicine, University of Iowa, Iowa City, IA, USA.,Pediatrics, University of Iowa, Iowa City, IA, USA
| | - Christie P Thomas
- Internal Medicine, University of Iowa, Iowa City, IA, USA.,Pediatrics, University of Iowa, Iowa City, IA, USA.,Veterans Affairs Medical Center, Iowa City, IA, USA
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Weaver CD, Denton JS. Next-generation inward rectifier potassium channel modulators: discovery and molecular pharmacology. Am J Physiol Cell Physiol 2021; 320:C1125-C1140. [PMID: 33826405 DOI: 10.1152/ajpcell.00548.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Inward rectifying potassium (Kir) channels play important roles in both excitable and nonexcitable cells of various organ systems and could represent valuable new drug targets for cardiovascular, metabolic, immune, and neurological diseases. In nonexcitable epithelial cells of the kidney tubule, for example, Kir1.1 (KCNJ1) and Kir4.1 (KCNJ10) are linked to sodium reabsorption in the thick ascending limb of Henle's loop and distal convoluted tubule, respectively, and have been explored as novel-mechanism diuretic targets for managing hypertension and edema. G protein-coupled Kir channels (Kir3) channels expressed in the central nervous system are critical effectors of numerous signal transduction pathways underlying analgesia, addiction, and respiratory-depressive effects of opioids. The historical dearth of pharmacological tool compounds for exploring the therapeutic potential of Kir channels has led to a molecular target-based approach using high-throughput screen (HTS) of small-molecule libraries and medicinal chemistry to develop "next-generation" Kir channel modulators that are both potent and specific for their targets. In this article, we review recent efforts focused specifically on discovery and improvement of target-selective molecular probes. The reader is introduced to fluorescence-based thallium flux assays that have enabled much of this work and then provided with an overview of progress made toward developing modulators of Kir1.1 (VU590, VU591), Kir2.x (ML133), Kir3.X (ML297, GAT1508, GiGA1, VU059331), Kir4.1 (VU0134992), and Kir7.1 (ML418). We discuss what is known about the small molecules' molecular mechanisms of action, in vitro and in vivo pharmacology, and then close with our view of what critical work remains to be done.
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Affiliation(s)
- C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee.,Department of Chemistry, Vanderbilt University, Nashville, Tennessee.,Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee
| | - Jerod S Denton
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee.,Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee.,Department of Anesthesiology, Vanderbilt University Medical Center, Nashville, Tennessee
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50
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Abstract
The known genetic architecture of blood pressure now comprises >30 genes, with rare variants resulting in monogenic forms of hypertension or hypotension and >1,477 common single-nucleotide polymorphisms (SNPs) being associated with the blood pressure phenotype. Monogenic blood pressure syndromes predominantly involve the renin-angiotensin-aldosterone system and the adrenal glucocorticoid pathway, with a smaller fraction caused by neuroendocrine tumours of the sympathetic and parasympathetic nervous systems. The SNPs identified in genome-wide association studies (GWAS) as being associated with the blood pressure phenotype explain only approximately 27% of the 30-50% estimated heritability of blood pressure, and the effect of each SNP on the blood pressure phenotype is small. A paucity of SNPs from GWAS are mapped to known genes causing monogenic blood pressure syndromes. For example, a GWAS signal mapped to the gene encoding uromodulin has been shown to affect blood pressure by influencing sodium homeostasis, and the effects of another GWAS signal were mediated by endothelin. However, the majority of blood pressure-associated SNPs show pleiotropic associations. Unravelling these associations can potentially help us to understand the underlying biological pathways. In this Review, we appraise the current knowledge of blood pressure genomics, explore the causal pathways for hypertension identified in Mendelian randomization studies and highlight the opportunities for drug repurposing and pharmacogenomics for the treatment of hypertension.
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Affiliation(s)
- Sandosh Padmanabhan
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK
| | - Anna F Dominiczak
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, UK.
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