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Huang YC, Liu CJ, Lu ZH, Huang HS. Long-Term Sodium Deficiency Reduces Sodium Excretion but Impairs Renal Function and Increases Stone Formation in Hyperoxaluric Calcium Oxalate Rats. Int J Mol Sci 2024; 25:3942. [PMID: 38612752 PMCID: PMC11011831 DOI: 10.3390/ijms25073942] [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] [Received: 02/25/2024] [Revised: 03/19/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
Excessive sodium intake is associated with nephrolithiasis, but the impact of sodium-deficient (SD) diets is unknown. Hence, we investigated the effects of short- and long-term SD diets on the expression of renal aquaporins and sodium transporters, and thus calcium oxalate (CaOx) crystal formation in hyperoxaluria rats. In a short-term sodium balance study, six male rats received drinking water and six received 0.75% ethylene glycol (EG) to induce hyperoxaluria. After a 30-day period of feeding on normal chow, both groups were treated with a normal-sodium diet for 5 days, followed by a sodium-free diet for the next 5 days. In a long-term SD study (42 days), four groups, induced with EG or not, were treated with normal-sodium water and sodium-free drinking water, alternately. Short-term sodium restriction in EG rats reversed the daily positive sodium balance, but progressively caused a negative cumulative water balance. In the long-term study, the abundant levels of of Na/H exchanger, thiazide-sensitive Na-Cl cotransporter, Na-K-ATPase, and aquaporins-1 from SD + EG rats were markedly reduced, corresponding to a decrease in Uosm, as compared to SD rats. Increased urine calcium, AP(CaOx)index, and renal CaOx deposition were also noted in SD + EG rats. Although the SD treatment reduced sodium excretion, it also increased urinary calcium and impaired renal function, ultimately causing the formation of more CaOx crystals.
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Affiliation(s)
| | | | | | - Ho-Shiang Huang
- Department of Urology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 704302, Taiwan; (Y.-C.H.); (C.-J.L.); (Z.-H.L.)
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2
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Trejo F, Elizalde S, Mercado A, Gamba G, de losHeros P. SLC12A cryo-EM: analysis of relevant ion binding sites, structural domains, and amino acids. Am J Physiol Cell Physiol 2023; 325:C921-C939. [PMID: 37545407 DOI: 10.1152/ajpcell.00089.2023] [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] [Received: 03/13/2023] [Revised: 07/24/2023] [Accepted: 07/24/2023] [Indexed: 08/08/2023]
Abstract
The solute carrier family 12A (SLC12A) superfamily of membrane transporters modulates the movement of cations coupled with chloride across the membrane. In doing so, these cotransporters are involved in numerous aspects of human physiology: cell volume regulation, ion homeostasis, blood pressure regulation, and neurological action potential via intracellular chloride concentration modulation. Their physiological characterization has been largely studied; however, understanding the mechanics of their function and the relevance of structural domains or specific amino acids has been a pending task. In recent years, single-particle cryogenic electron microscopy (cryo-EM) has been successfully applied to members of the SLC12A family including all K+:Cl- cotransporters (KCCs), Na+:K+:2Cl- cotransporter NKCC1, and recently Na+:Cl- cotransporter (NCC); revealing structural elements that play key roles in their function. The present review analyzes the data provided by these cryo-EM reports focusing on structural domains and specific amino acids involved in ion binding, domain interactions, and other important SCL12A structural elements. A comparison of cryo-EM data from NKCC1 and KCCs is presented in the light of the two recent NCC cryo-EM studies, to propose insight into structural elements that might also be found in NCC and are necessary for its proper function. In the final sections, the importance of key coordination residues for substrate specificity and their implication on various pathophysiological conditions and genetic disorders is reviewed, as this could provide the basis to correlate structural elements with the development of novel and selective treatments, as well as mechanistic insight into the function and regulation of cation-coupled chloride cotransporters (CCCs).
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Affiliation(s)
- Fátima Trejo
- Unidad de Investigación UNAM-INC, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Stephanie Elizalde
- Departamento de Nefrología y Metabolismo Mineral, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Adriana Mercado
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, Mexico City, Mexico
| | - Gerardo Gamba
- Departamento de Nefrología y Metabolismo Mineral, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Paola de losHeros
- Unidad de Investigación UNAM-INC, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
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3
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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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4
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Nan J, Yuan Y, Yang X, Shan Z, Liu H, Wei F, Zhang W, Zhang Y. Cryo-EM structure of the human sodium-chloride cotransporter NCC. SCIENCE ADVANCES 2022; 8:eadd7176. [PMID: 36351028 PMCID: PMC9645730 DOI: 10.1126/sciadv.add7176] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 09/21/2022] [Indexed: 05/29/2023]
Abstract
The sodium-chloride cotransporter NCC mediates the coupled import of sodium and chloride across the plasma membrane, playing vital roles in kidney extracellular fluid volume and blood pressure control. Here, we present the full-length structure of human NCC, with 2.9 Å for the transmembrane domain and 3.8 Å for the carboxyl-terminal domain. NCC adopts an inward-open conformation and a domain-swap dimeric assembly. Conserved ion binding sites among the cation-chloride cotransporters and the Na2 site are observed in our structure. A unique His residue in the substrate pocket in NCC potentially interacts with Na1 and Cl1 and might also mediate the coordination of Na2 through a Ser residue. Putative observed water molecules are indicated to participate in the coordination of ions and TM coupling. Together with transport activity assays, our structure provides the first glimpse of NCC and defines ion binding sites, promoting drug development for hypertension targeting on NCC.
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Affiliation(s)
- Jing Nan
- Shanghai Fifth People’s Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Yafei Yuan
- Beijing Frontier Research Center for Biological Structure, Beijing Advanced Innovation Center for Structural Biology, Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Xuemei Yang
- Shanghai Fifth People’s Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Ziyang Shan
- Shanghai Fifth People’s Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Huihui Liu
- Warshel Institute for Computational Biology, School of Life and Health Sciences, The Chinese University of Hong Kong, Shenzhen 518172, Guangdong, China
| | - Feiwen Wei
- Shanghai Fifth People’s Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Wei Zhang
- Shanghai Fifth People’s Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
| | - Yanqing Zhang
- Shanghai Fifth People’s Hospital, Fudan University, and Shanghai Key Laboratory of Medical Epigenetics, International Co-laboratory of Medical Epigenetics and Metabolism (Ministry of Science and Technology), Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
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5
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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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6
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Tang W, Chai Y, Jia H, Wang B, Liu T, Wang H, Dai C. Different roles of the RAAS affect bone metabolism in patients with primary aldosteronism, Gitelman syndrome and Bartter syndrome. BMC Endocr Disord 2022; 22:38. [PMID: 35148746 PMCID: PMC8840772 DOI: 10.1186/s12902-022-00955-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 02/07/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Components of the RAAS may influence bone metabolism. Different roles of the RAAS are found in patients with primary aldosteronism (PA), Gitelman syndrome (GS) and Bartter syndrome (BS). We collected inpatient medical records including 20 patients with Gitelman syndrome (GS group), 17 patients with Bartter syndrome (BS group) and 20 age-matched patients with primary aldosteronism (PA group). We found the following results. (1) PA patients had significantly higher serum magnesium, potassium, plasma aldosterone, serum parathyroid hormone, urinary calcium and BMI (p<0.05) while significantly lower serum calcium and phosphorus (P < 0.05) than GS and BS patients. (2) Total hip and femoral neck bone mineral density (BMD) in PA patients were significantly lower than those in GS and BS patients (P<0.05). (3) GS patients had lower serum magnesium and urinary calcium than BS patients (P < 0.05). (4) Compared with BS patients, the vertebral BMD in GS patients were significantly higher (P < 0.05). So we believe higher aldosterone and PTH levels may be the reason that PA patients have lower hip BMD. Lower urinary calcium and inactivation of the NCC gene (Na-Cl cotransporter) in GS patients may have protective effects on vertebral bone mineral density. CONCLUSIONS With persistence disordered RAAS, PA patients have lower BMD, especially hip BMD as compared with GS and BS patients. We presumed the lower renin and higher aldosterone level may be the reason. With the same level of renin and aldosterone, BS patients have lower vertebrate BMD than GS patients. Decreased urinary calcium excretion may be the reason.
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Affiliation(s)
- Wangna Tang
- Endocrinology and Metabolism Disease Department, Tianjin Medical University General Hospital, 154# Anshan Road, Heping District, Tianjin, 300052, China
| | - Yun Chai
- Endocrinology and Metabolism Disease Department, Tianjin Medical University General Hospital, 154# Anshan Road, Heping District, Tianjin, 300052, China
| | - Hongwei Jia
- Endocrinology and Metabolism Disease Department, Tianjin Medical University General Hospital, 154# Anshan Road, Heping District, Tianjin, 300052, China
| | - Baoping Wang
- Endocrinology and Metabolism Disease Department, Tianjin Medical University General Hospital, 154# Anshan Road, Heping District, Tianjin, 300052, China
| | - Tong Liu
- Endocrinology and Metabolism Disease Department, Tianjin Medical University General Hospital, 154# Anshan Road, Heping District, Tianjin, 300052, China
| | - Hao Wang
- Endocrinology and Metabolism Disease Department, Tianjin Medical University General Hospital, 154# Anshan Road, Heping District, Tianjin, 300052, China
| | - Chenlin Dai
- Endocrinology and Metabolism Disease Department, Tianjin Medical University General Hospital, 154# Anshan Road, Heping District, Tianjin, 300052, China.
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7
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Chen B, Fluitt MB, Brown AL, Scott S, Gadicherla A, Ecelbarger CM. Selective Deletion of the Mechanistic Target of Rapamycin From the Renal Collecting Duct Principal Cell in Mice Down-Regulates the Epithelial Sodium Channel. Front Physiol 2022; 12:787521. [PMID: 35058797 PMCID: PMC8764147 DOI: 10.3389/fphys.2021.787521] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/15/2021] [Indexed: 12/17/2022] Open
Abstract
The mechanistic target of rapamycin (mTOR), a serine-threonine-specific kinase, is a cellular energy sensor, integrating growth factor and nutrient signaling. In the collecting duct (CD) of the kidney, the epithelial sodium channel (ENaC) essential in the determination of final urine Na+ losses, has been demonstrated to be upregulated by mTOR, using cell culture and mTOR inhibition in ex vivo preparations. We tested whether CD-principal cell (PC) targeted deletion of mTOR using Cre-lox recombination would affect whole-body sodium homeostasis, blood pressure, and ENaC regulation in mice. Male and female CD-PC mTOR knockout (KO) mice and wild-type (WT) littermates (Cre-negative) were generated using aquaporin-2 (AQP2) promoter to drive Cre-recombinase. Under basal conditions, KO mice showed a reduced (∼30%) natriuretic response to benzamil (ENaC) antagonist, suggesting reduced in vivo ENaC activity. WT and KO mice were fed normal sodium (NS, 0.45% Na+) or a very low Na+ (LS, <0.02%) diet for 7-days. Switching from NS to LS resulted in significantly higher urine sodium losses (relative to WT) in the KO with adaptation occurring by day 2. Blood pressures were modestly (∼5-10 mm Hg) but significantly lower in KO mice under both diets. Western blotting showed KO mice had 20-40% reduced protein levels of all three subunits of ENaC under LS or NS diet. Immunohistochemistry (IHC) of kidney showed enhanced apical-vs.-cellular localization of all three subunits with LS, but a reduction in this ratio for γ-ENaC in the KO. Furthermore, the KO kidneys showed increased ubiquitination of α-ENaC and reduced phosphorylation of the serum and glucocorticoid regulated kinase, type 1 [serum glucocorticoid regulated kinase (SGK1)] on serine 422 (mTOR phosphorylation site). Taken together this suggests enhanced degradation as a consequence of reduced mTOR kinase activity and downstream upregulation of ubiquitination may have accounted for the reduction at least in α-ENaC. Overall, our data support a role for mTOR in ENaC activity likely via regulation of SGK1, ubiquitination, ENaC channel turnover and apical membrane residency. These data support a role for mTOR in the collecting duct in the maintenance of body sodium homeostasis.
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Affiliation(s)
- Bruce Chen
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC, United States
| | - Maurice B. Fluitt
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC, United States
- Department of Medicine, Howard University, Washington, DC, United States
| | - Aaron L. Brown
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC, United States
| | - Samantha Scott
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC, United States
| | - Anirudh Gadicherla
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC, United States
| | - Carolyn M. Ecelbarger
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC, United States
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8
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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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9
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Review and Analysis of Two Gitelman Syndrome Pedigrees Complicated with Proteinuria or Hashimoto's Thyroiditis Caused by Compound Heterozygous SLC12A3 Mutations. BIOMED RESEARCH INTERNATIONAL 2021; 2021:9973161. [PMID: 34046503 PMCID: PMC8128541 DOI: 10.1155/2021/9973161] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 04/25/2021] [Accepted: 05/03/2021] [Indexed: 02/07/2023]
Abstract
Gitelman syndrome (GS) is an autosomal recessive inherited salt-losing renal tubular disease, which is caused by a pathogenic mutation of SLC12A3 encoding thiazide-sensitive Na-Cl cotransporter, which leads to disturbance of sodium and chlorine reabsorption in renal distal convoluted tubules, resulting in phenotypes such as hypovolemia, renin angiotensin aldosterone system (RAAS) activation, hypokalemia, and metabolic alkalosis. In this study, two GS families with proteinuria or Hashimoto's thyroiditis were analyzed for genetic-phenotypic association. Sanger sequencing revealed that two probands carried SLC12A3 compound heterozygous mutations, and proband A carried two pathogenic mutations: missense mutation Arg83Gln, splicing mutation, or frameshift mutation NC_000016.10:g.56872655_56872667 (gcggacatttttg>accgaaaatttt) in exon 8. Proband B carries two missense mutations: novel Asp839Val and Arg904Gln. Both probands manifested hypokalemia, hypomagnesemia, hypocalcinuria, metabolic alkalosis, and RAAS activation; in addition, the proband A exhibited decreased urinary chloride, phosphorus, and increased magnesium ions excretion, complicated with Hashimoto's Thyroiditis, while the proband B exhibited enhanced urine sodium excretion and proteinuria. The older sister of proband B with GS also had Hashimoto's thyroiditis. Electron microscopy revealed swelling and vacuolar degeneration of glomerular epithelial cells, diffuse proliferation of mesangial cells and matrix, accompanied by a small amount of low-density electron-dense deposition, and segmental fusion of epithelial cell foot processes in proband B. Light microscopy showed mild mesangial hyperplasia in the focal segment of the glomerulus, hyperplasia, and hypertrophy of juxtaglomerular apparatus cells, mild renal tubulointerstitial lesions, and one glomerular sclerosis. So, long-term hypokalemia of GS can cause kidney damage and may also be susceptible to thyroid disease.
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10
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Yang X, Wang Q, Cao E. Structure of the human cation-chloride cotransporter NKCC1 determined by single-particle electron cryo-microscopy. Nat Commun 2020; 11:1016. [PMID: 32081947 PMCID: PMC7035313 DOI: 10.1038/s41467-020-14790-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 01/29/2020] [Indexed: 11/09/2022] Open
Abstract
The secondary active cation-chloride cotransporters (CCCs) utilize the existing Na+ and/or K+ gradients to move Cl- into or out of cells. NKCC1 is an intensively studied member of the CCC family and plays fundamental roles in regulating trans-epithelial ion movement, cell volume, chloride homeostasis and neuronal excitability. Here, we report a cryo-EM structure of human NKCC1 captured in a partially loaded, inward-open state. NKCC1 assembles into a dimer, with the first ten transmembrane (TM) helices harboring the transport core and TM11-TM12 helices lining the dimer interface. TM1 and TM6 helices break α-helical geometry halfway across the lipid bilayer where ion binding sites are organized around these discontinuous regions. NKCC1 may harbor multiple extracellular entryways and intracellular exits, raising the possibility that K+, Na+, and Cl- ions may traverse along their own routes for translocation. NKCC1 structure provides a blueprint for further probing structure-function relationships of NKCC1 and other CCCs.
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Affiliation(s)
- Xiaoyong Yang
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, 84112-5650, USA
| | - Qinzhe Wang
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, 84112-5650, USA
| | - Erhu Cao
- Department of Biochemistry, University of Utah School of Medicine, Salt Lake City, UT, 84112-5650, USA.
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11
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Rapoport RM, Soleimani M. Mechanism of Thiazide Diuretic Arterial Pressure Reduction: The Search Continues. Front Pharmacol 2019; 10:815. [PMID: 31543812 PMCID: PMC6730501 DOI: 10.3389/fphar.2019.00815] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 06/24/2019] [Indexed: 12/21/2022] Open
Abstract
Thiazide diuretic (TZD)-mediated chronic reduction of arterial pressure is thought to occur through decreased total peripheral vascular resistance. Further, the decreased peripheral vascular resistance is accomplished through TZD activation of an extrarenal target, resulting in inhibition of vascular constriction. However, despite greater than five decades of investigation, little progress has been made into the identification of the TZD extrarenal target. Proposed mechanisms range from direct inhibition of constrictor and activation of relaxant signaling pathways in the vascular smooth muscle to indirect inhibition through decreased neurogenic and hormonal regulatory pathways. Surprisingly, particularly in view of this lack of progress, comprehensive reviews of the subject are absent. Moreover, even though it is well recognized that 1) several types of hypertension are insensitive to TZD reduction of arterial pressure and, further, TZD fail to reduce arterial pressure in normotensive subjects and animals, and 2) different mechanisms underlie acute and chronic TZD, findings derived from these models and parameters remain largely undifferentiated. This review 1) comprehensively describes findings associated with TZD reduction of arterial pressure; 2) differentiates between observations in TZD-sensitive and TZD-insensitive hypertension, normotensive subjects/animals, and acute and chronic effects of TZD; 3) critically evaluates proposed TZD extrarenal targets; 4) proposes guiding parameters for relevant investigations into extrarenal TZD target identification; and 5) proposes a working model for TZD chronic reduction of arterial pressure through vascular dilation.
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Affiliation(s)
- Robert M Rapoport
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| | - Manoocher Soleimani
- Research Service, Veterans Affairs Medical Center, Cincinnati, OH, United States.,Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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12
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Structure and mechanism of the cation-chloride cotransporter NKCC1. Nature 2019; 572:488-492. [PMID: 31367042 DOI: 10.1038/s41586-019-1438-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 06/24/2019] [Indexed: 01/01/2023]
Abstract
Cation-chloride cotransporters (CCCs) mediate the electroneutral transport of chloride, potassium and/or sodium across the membrane. They have critical roles in regulating cell volume, controlling ion absorption and secretion across epithelia, and maintaining intracellular chloride homeostasis. These transporters are primary targets for some of the most commonly prescribed drugs. Here we determined the cryo-electron microscopy structure of the Na-K-Cl cotransporter NKCC1, an extensively studied member of the CCC family, from Danio rerio. The structure defines the architecture of this protein family and reveals how cytosolic and transmembrane domains are strategically positioned for communication. Structural analyses, functional characterizations and computational studies reveal the ion-translocation pathway, ion-binding sites and key residues for transport activity. These results provide insights into ion selectivity, coupling and translocation, and establish a framework for understanding the physiological functions of CCCs and interpreting disease-related mutations.
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Kelley EF, Snyder EM, Alkhatib NS, Snyder SC, Sprissler R, Olson TP, Akre MK, Abraham I. Economic evaluation of a pharmacogenomic multi-gene panel test to optimize anti-hypertension therapy: simulation study. J Med Econ 2018; 21:1246-1253. [PMID: 30280614 DOI: 10.1080/13696998.2018.1531011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
AIMS Hypertension is the strongest modifiable risk factor for cardiovascular disease, affecting 80 million individuals in the US and responsible for ∼360,000 deaths, at total annual costs of $93.5 billion. Antihypertension therapies guided by single genotypes are clinically more effective and may avert more adverse events than the standard of care of layering anti-hypertensive drug therapies, thus potentially decreasing costs. This study aimed to determine the economic benefits of the implementation of multi-gene panel guided therapies for hypertension from the payer perspective within a 3-year time horizon. MATERIALS AND METHODS A simulation analysis was conducted for a panel of 10 million insured patients categorized clinically as untreated, treated but uncontrolled, and treated and controlled over a 3-year treatment period. Inputs included research data; empirical data from a 11-gene panel with known functional, heart, blood vessel, and kidney genotypes; and therapy efficacy and safety estimates from literature. Cost estimates were categorized as related to genetic testing, evaluation and management, medication, or adverse events. RESULTS Multi-gene panel guided therapy yielding savings of $6,256,607,500 for evaluation and management, $908,160,000 for medications, and $37,467,508,716 for adverse events, after accounting for incremental genetic testing costs of $2,355,540,000. This represents total 3-year savings of $42,276,736,216, or a 47% reduction, and 3-year savings of $4,228 and annual savings of $1,409 per covered patient. CONCLUSIONS A precision medicine approach to genetically guided therapy for hypertension patients using a multi-gene panel reduced total 3-year costs by 47%, yielding savings exceeding $42.3 billion in an insured panel of 10 million patients. Importantly, 89% of these savings are generated by averting specific adverse events and, thus, optimizing choice of therapy in function of both safety and efficacy.
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Affiliation(s)
- Eli F Kelley
- a University of Minnesota , Minneapolis , MN , USA
| | | | - Nimer S Alkhatib
- c University of Arizona, Center for Health Outcomes and Pharmaco Economic Research , Tucson , AZ , USA
| | | | - Ryan Sprissler
- b Geneticure, Inc. , Rochester , MN , USA
- d University of Arizona Genomics Core , Tucson , AZ , USA
- e University of Arizona, Center for Applied Genetics and Genomic Medicine , Tucson , AZ , USA
| | - Thomas P Olson
- f Mayo Clinic, College of Medicine , Rochester , MN , USA
| | | | - Ivo Abraham
- c University of Arizona, Center for Health Outcomes and Pharmaco Economic Research , Tucson , AZ , USA
- e University of Arizona, Center for Applied Genetics and Genomic Medicine , Tucson , AZ , USA
- g University of Arizona , Department of Family and Community Medicine , Tucson , AZ , USA
- h Matrix45 , Tucson , AZ , USA
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Wetendorf M, Wu SP, Wang X, Creighton CJ, Wang T, Lanz RB, Blok L, Tsai SY, Tsai MJ, Lydon JP, DeMayo FJ. Decreased epithelial progesterone receptor A at the window of receptivity is required for preparation of the endometrium for embryo attachment. Biol Reprod 2018; 96:313-326. [PMID: 28203817 DOI: 10.1095/biolreprod.116.144410] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 12/23/2016] [Accepted: 01/03/2017] [Indexed: 01/25/2023] Open
Abstract
The precise timing of progesterone signaling through its cognate receptor, the progesterone receptor (PGR), is critical for the establishment and maintenance of pregnancy. Loss of PGR expression in the murine uterine epithelium during the preimplantation period is a marker for uterine receptivity and embryo attachment. We hypothesized that the decrease in progesterone receptor A (PGRA) expression is necessary for successful embryo implantation. To test this hypothesis, a mouse model constitutively expressing PGRA (mPgrALsL/+) was generated. Expression of PGRA in all uterine compartments (Pgrcre) or uterine epithelium (Wnt7acre) resulted in infertility with defects in embryo attachment and stromal decidualization. Expression of critical PGRA target genes, indian hedgehog, and amphiregulin (Areg), was maintained through the window of receptivity while the estrogen receptor target gene, the leukemia inhibitory factor (Lif), a key regulator of embryo receptivity, was decreased. Transcriptomic and cistromic analyses of the mouse uterus at day 4.5 of pregnancy identified an altered group of genes regulating molecular transport in the control of fluid and ion levels within the uterine interstitial space. Additionally, LIF and its cognate receptor, the leukemia inhibitory factor receptor (LIFR), exhibited PGR-binding events in regions upstream of the transcriptional start sites, suggesting PGRA is inhibiting transcription at these loci. Therefore, downregulation of the PGRA isoform at the window of receptivity is necessary for the attenuation of hedgehog signaling, transcriptional activation of LIF signaling, and modulation of solutes and fluid, producing a receptive environment for the attaching embryo.
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Affiliation(s)
- Margeaux Wetendorf
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, North Carolina, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA.,Integrative Molecular and Biomedical Sciences Graduate Program, Baylor College of Medicine, Houston, Texas, USA
| | - San-Pin Wu
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, North Carolina, USA
| | - Xiaoqiu Wang
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, North Carolina, USA
| | - Chad J Creighton
- Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, Texas, USA
| | - Tianyuan Wang
- Integrative Bioinformatics, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, North Carolina, USA
| | - Rainer B Lanz
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Leen Blok
- Department of Obstetrics and Gynaecology, Erasmus MC Cancer Institute, University Medical Center Rotterdam, Rotterdam, The Netherlands
| | - Sophia Y Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Ming-Jer Tsai
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - John P Lydon
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Francesco J DeMayo
- Reproductive and Developmental Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, Durham, North Carolina, USA
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Ravarotto V, Loffing J, Loffing-Cueni D, Heidemeyer M, Pagnin E, Calò LA, Rossi GP. Gitelman's Syndrome: characterization of a novel c.1181G>A point mutation and functional classification of the known mutations. Hypertens Res 2018; 41:578-588. [PMID: 29925901 DOI: 10.1038/s41440-018-0061-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 12/22/2017] [Accepted: 12/29/2017] [Indexed: 12/18/2022]
Abstract
We have investigated the mechanisms by which a novel missense point mutation (c.1181G>A) found in two sisters causes Gitelman's syndrome by impairing the sodium chloride co-transporter (NCC, encoded by SLC12A3 gene) function. The cDNA and in vitro transcribed mRNA of either wild-type or mutated SLC12A3 were transfected into HEK293 cells and injected into Xenopus laevis oocytes, respectively. The expression, maturation, trafficking, and function of the mutated and wild-type NCC were assessed by Western blotting, immunohistochemistry and 22Na+ uptake studies. By immunoblotting of lysates from HEK293 cells and oocytes expressing wild-type NCC, two NCC-related bands of approximately 130 kDa and 115 kDa, corresponding to fully and core-glycosylated NCC, respectively, were identified. In contrast, the mutant NCC only showed a single band of approximately 115 kDa, indicating impaired maturation of the protein. Moreover, oocytes injected with wild-type NCC showed thiazide-sensitive 22Na+ uptake, which was absent in those injected with the mutant NCC. The novel mutation was discussed in the context of the functionally characterized NCC mutations causing Gitelman's syndrome, which fit into five classes. In conclusion, the functional characterization of this novel Gly394Asp NCC and its localization on the NCC structure, alongside that of previously known mutations causing Gitelman's syndrome, may provide novel information on the function of the different domains of the human NCC.
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Affiliation(s)
- Verdiana Ravarotto
- Internal Medicine, Department of Medicine-DIMED, University of Padova, Padova, Italy.,Nephrology, Department of Medicine-DIMED, University of Padova, Padova, Italy
| | | | | | | | - Elisa Pagnin
- Nephrology, Department of Medicine-DIMED, University of Padova, Padova, Italy
| | - Lorenzo A Calò
- Nephrology, Department of Medicine-DIMED, University of Padova, Padova, Italy
| | - Gian Paolo Rossi
- Internal Medicine, Department of Medicine-DIMED, University of Padova, Padova, Italy.
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