1
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Rioux AV, Nsimba-Batomene TR, Slimani S, Bergeron NAD, Gravel MAM, Schreiber SV, Fiola MJ, Haydock L, Garneau AP, Isenring P. Navigating the multifaceted intricacies of the Na +-Cl - cotransporter, a highly regulated key effector in the control of hydromineral homeostasis. Physiol Rev 2024; 104:1147-1204. [PMID: 38329422 DOI: 10.1152/physrev.00027.2023] [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: 07/20/2023] [Revised: 01/01/2024] [Accepted: 02/03/2024] [Indexed: 02/09/2024] Open
Abstract
The Na+-Cl- cotransporter (NCC; SLC12A3) is a highly regulated integral membrane protein that is known to exist as three splice variants in primates. Its primary role in the kidney is to mediate the cosymport of Na+ and Cl- across the apical membrane of the distal convoluted tubule. Through this role and the involvement of other ion transport systems, NCC allows the systemic circulation to reclaim a fraction of the ultrafiltered Na+, K+, Cl-, and Mg+ loads in exchange for Ca2+ and [Formula: see text]. The physiological relevance of the Na+-Cl- cotransport mechanism in humans is illustrated by several abnormalities that result from NCC inactivation through the administration of thiazides or in the setting of hereditary disorders. The purpose of the present review is to discuss the molecular mechanisms and overall roles of Na+-Cl- cotransport as the main topics of interest. On reading the narrative proposed, one will realize that the knowledge gained in regard to these themes will continue to progress unrelentingly no matter how refined it has now become.
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Affiliation(s)
- A V Rioux
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - T R Nsimba-Batomene
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - S Slimani
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - N A D Bergeron
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - M A M Gravel
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - S V Schreiber
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - M J Fiola
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
| | - L Haydock
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
- Service de Néphrologie-Transplantation Rénale Adultes, Hôpital Necker-Enfants Malades, AP-HP, INSERM U1151, Université Paris Cité, Paris, France
| | - A P Garneau
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
- Service de Néphrologie-Transplantation Rénale Adultes, Hôpital Necker-Enfants Malades, AP-HP, INSERM U1151, Université Paris Cité, Paris, France
| | - P Isenring
- Department of Medicine, Nephrology Research Group, Laval University, Quebec City, Quebec, Canada
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2
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Greenberg D, Rosenblum ND, Tonelli M. The multifaceted links between hearing loss and chronic kidney disease. Nat Rev Nephrol 2024; 20:295-312. [PMID: 38287134 DOI: 10.1038/s41581-024-00808-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/04/2024] [Indexed: 01/31/2024]
Abstract
Hearing loss affects nearly 1.6 billion people and is the third-leading cause of disability worldwide. Chronic kidney disease (CKD) is also a common condition that is associated with adverse clinical outcomes and high health-care costs. From a developmental perspective, the structures responsible for hearing have a common morphogenetic origin with the kidney, and genetic abnormalities that cause familial forms of hearing loss can also lead to kidney disease. On a cellular level, normal kidney and cochlea function both depend on cilial activities at the apical surface, and kidney tubular cells and sensory epithelial cells of the inner ear use similar transport mechanisms to modify luminal fluid. The two organs also share the same collagen IV basement membrane network. Thus, strong developmental and physiological links exist between hearing and kidney function. These theoretical considerations are supported by epidemiological data demonstrating that CKD is associated with a graded and independent excess risk of sensorineural hearing loss. In addition to developmental and physiological links between kidney and cochlear function, hearing loss in patients with CKD may be driven by specific medications or treatments, including haemodialysis. The associations between these two common conditions are not commonly appreciated, yet have important implications for research and clinical practice.
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Affiliation(s)
- Dina Greenberg
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Norman D Rosenblum
- Program in Developmental and Stem Cell Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, Temerty Faculty of Medicine, Toronto, Ontario, Canada
- Department of Paediatrics, Temerty Faculty of Medicine, Toronto, Ontario, Canada
| | - Marcello Tonelli
- Department of Medicine, University of Calgary, Calgary, Alberta, Canada.
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3
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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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4
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Burd SG, Lebedeva AV, Rubleva YV, Pantina NV, Yurchenko AV, Bogomazova MA, Kovaleva II, Karchevskaya AE. [Epilepsy syndromes associated with hearing loss]. Zh Nevrol Psikhiatr Im S S Korsakova 2023; 123:28-33. [PMID: 36719116 DOI: 10.17116/jnevro202312301128] [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: 02/01/2023]
Abstract
Patients with epilepsy who have also hearing loss represent a distinct group of patients, often with aggravated medical history, comorbidities and high potential for disability. The etiopathogenetic factors of epilepsy and hearing loss may be common to these conditions (neuroinfections, craniocerebral injuries, cerebral circulatory disorders, perinatal pathology, etc.). In addition, these two syndromes may occur as part of hereditary diseases, so their timely recognition and genetic diagnosis are important for determining further medical and genetic prognosis. This article provides an overview of orphan genetic diseases associated with epilepsy and hearing loss - MERRF syndrome, MELAS syndrome, EAST syndrome, Ayme-Grippsyndrome, epilepsy, hearing loss and mental retardation syndromes, associated with mutations in SPATA5 gene, DOOR syndrome, Gustavson syndrome.
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Affiliation(s)
- S G Burd
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia.,Pirogov Russian National Research Medical University, Moscow, Russia
| | - A V Lebedeva
- Pirogov Russian National Research Medical University, Moscow, Russia
| | - Yu V Rubleva
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
| | - N V Pantina
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
| | - A V Yurchenko
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
| | - M A Bogomazova
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
| | - I I Kovaleva
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
| | - A E Karchevskaya
- Federal Center of Brain Research and Neurotechnologies, Moscow, Russia
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5
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Beverley KM, Pattnaik BR. Inward rectifier potassium (Kir) channels in the retina: living our vision. Am J Physiol Cell Physiol 2022; 323:C772-C782. [PMID: 35912989 PMCID: PMC9448332 DOI: 10.1152/ajpcell.00112.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/25/2022] [Accepted: 07/25/2022] [Indexed: 11/22/2022]
Abstract
Channel proteins are vital for conducting ions throughout the body and are especially relevant to retina physiology. Inward rectifier potassium (Kir) channels are a class of K+ channels responsible for maintaining membrane potential and extracellular K+ concentrations. Studies of the KCNJ gene (that encodes Kir protein) expression identified the presence of all of the subclasses (Kir 1-7) of Kir channels in the retina or retinal-pigmented epithelium (RPE). However, functional studies have established the involvement of the Kir4.1 homotetramer and Kir4.1/5.1 heterotetramer in Müller glial cells, Kir2.1 in bipolar cells, and Kir7.1 in the RPE cell physiology. Here, we propose the potential roles of Kir channels in the retina based on the physiological contributions to the brain, pancreatic, and cardiac tissue functions. There are several open questions regarding the expressed KCNJ genes in the retina and RPE. For example, why does not the Kir channel subtype gene expression correspond with protein expression? Catching up with multiomics or functional "omics" approaches might shed light on posttranscriptional changes that might influence Kir subunit mRNA translation within the retina that guides our vision.
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Affiliation(s)
- Katie M Beverley
- Endocrinology and Reproductive Physiology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin
| | - Bikash R Pattnaik
- Endocrinology and Reproductive Physiology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
- Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin
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6
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Alhasan K, D'Alessandri-Silva C, Mongia A, Topaloglu R, Tasic V, Filler G. Young Adults With Hereditary Tubular Diseases: Practical Aspects for Adult-Focused Colleagues. Adv Chronic Kidney Dis 2022; 29:292-307. [PMID: 36084976 DOI: 10.1053/j.ackd.2021.11.004] [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: 09/21/2021] [Revised: 11/07/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Recent advances in the management of kidney tubular diseases have resulted in a significant cohort of adolescents and young adults transitioning from pediatric- to adult-focused care. Most of the patients under adult-focused care have glomerular diseases, whereas rarer tubular diseases form a considerable proportion of pediatric patients. The purpose of this review is to highlight the clinical signs and symptoms of tubular disorders, as well as their diagnostic workup, including laboratory findings and imaging, during young adulthood. We will then discuss more common disorders such as cystinosis, cystinuria, distal kidney tubular acidosis, congenital nephrogenic diabetes insipidus, Dent disease, rickets, hypercalciuria, and syndromes such as Bartter, Fanconi, Gitelman, Liddle, and Lowe. This review is a practical guide on the diagnostic and therapeutic approach of tubular conditions affecting young adults who are transitioning to adult-focused care.
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Affiliation(s)
- Khalid Alhasan
- Department of Pediatrics, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Cynthia D'Alessandri-Silva
- Department of Pediatrics, University of Connecticut School of Medicine, Farmington, and Nephrology, Connecticut Children's Medical Center, Hartford, CT
| | - Anil Mongia
- Department of Pediatrics, SUNY Downstate Medical Center, Brooklyn, NY
| | - Rezan Topaloglu
- Department of Paediatrics, Division of Pediatric Nephrology, Hacettepe University School of Medicine, Ankara, Turkey
| | - Velibor Tasic
- University Children's Hospital, Medical School, Skopje, North Macedonia
| | - Guido Filler
- Department of Paediatrics, Division of Pediatric Nephrology, Western University, London, ON, Canada; Department of Medicine, Western University, London, ON, Canada; Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
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7
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Lo J, Forst AL, Warth R, Zdebik AA. EAST/SeSAME Syndrome and Beyond: The Spectrum of Kir4.1- and Kir5.1-Associated Channelopathies. Front Physiol 2022; 13:852674. [PMID: 35370765 PMCID: PMC8965613 DOI: 10.3389/fphys.2022.852674] [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] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 02/08/2022] [Indexed: 12/13/2022] Open
Abstract
In 2009, two groups independently linked human mutations in the inwardly rectifying K+ channel Kir4.1 (gene name KCNJ10) to a syndrome affecting the central nervous system (CNS), hearing, and renal tubular salt reabsorption. The autosomal recessive syndrome has been named EAST (epilepsy, ataxia, sensorineural deafness, and renal tubulopathy) or SeSAME syndrome (seizures, sensorineural deafness, ataxia, intellectual disability, and electrolyte imbalance), accordingly. Renal dysfunction in EAST/SeSAME patients results in loss of Na+, K+, and Mg2+ with urine, activation of the renin-angiotensin-aldosterone system, and hypokalemic metabolic alkalosis. Kir4.1 is highly expressed in affected organs: the CNS, inner ear, and kidney. In the kidney, it mostly forms heteromeric channels with Kir5.1 (KCNJ16). Biallelic loss-of-function mutations of Kir5.1 can also have disease significance, but the clinical symptoms differ substantially from those of EAST/SeSAME syndrome: although sensorineural hearing loss and hypokalemia are replicated, there is no alkalosis, but rather acidosis of variable severity; in contrast to EAST/SeSAME syndrome, the CNS is unaffected. This review provides a framework for understanding some of these differences and will guide the reader through the growing literature on Kir4.1 and Kir5.1, discussing the complex disease mechanisms and the variable expression of disease symptoms from a molecular and systems physiology perspective. Knowledge of the pathophysiology of these diseases and their multifaceted clinical spectrum is an important prerequisite for making the correct diagnosis and forms the basis for personalized therapies.
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Affiliation(s)
- Jacky Lo
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - Anna-Lena Forst
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Richard Warth
- Medical Cell Biology, Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Anselm A. Zdebik
- Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
- Centre for Nephrology, University College London, London, United Kingdom
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8
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Suzumoto Y, Columbano V, Gervasi L, Giunta R, Mattina T, Trimarchi G, Capolongo G, Simeoni M, Perna AF, Zacchia M, Toriello G, Pollastro RM, Rapisarda F, Capasso G, Trepiccione F. A case series of adult patients affected by EAST/SeSAME syndrome suggests more severe disease in subjects bearing KCNJ10 truncating mutations. Intractable Rare Dis Res 2021; 10:95-101. [PMID: 33996354 PMCID: PMC8122315 DOI: 10.5582/irdr.2020.03158] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
EAST/SeSAME syndrome is a rare disease affecting the Central Nervous System (CNS), inner ear, and kidney. The syndrome is due to loss-of-function mutations in the KCNJ10 gene encoding the inward-rectifying potassium channel Kir4.1. EAST/SeSAME syndrome is mainly diagnosed during childhood with a tonic-clonic seizure being the usual first symptom. Due to a limited number of patients and recent identification of the disease, few data are available on the clinical progress of this disease in adulthood. In particular, neurologic and nephrological outcomes have not been reported. We present a case series of 4 adult patients harbouring homozygous missense mutation p.Ala167Val and homozygous frameshift mutations p.Asn232Glnfs*14 and p.Gly275Valfs*7. Effects of these mutations were predicted by in silico modelling and bioinformatic tools. Patients with truncating mutations were associated with more severe outcomes, both in tubulopathy severity and neurological symptomatology. Conversely, either missense or truncating mutations were correlated with similar severity of epilepsy, with a long free-of-event period up to 20 years old. No eGFR decline was documented. Modelling predicted that truncating mutations lead to complete Kir4.1 dysfunction. Finally, all patients had a mild increase in urinary protein excretion. Our study indicates that the prognosis of patients suffering from EAST/SeSAME syndrome is related to the severity of the mutation causing the disease. As predicted by in silico modelling, truncating mutations of KCNJ10 are associated with more severe disease, with recurrence of symptomatic hypokalemia and more severe neurological phenotype. The type of mutation should be considered for the therapy tailored to patients' phenotype.
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Affiliation(s)
| | - Valeria Columbano
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Luciano Gervasi
- School of Nephrology, Department of Clinical and Experimental Medicine, University of Catania, Italy
| | - Rosa Giunta
- School of Nephrology, Department of Clinical and Experimental Medicine, University of Catania, Italy
| | - Teresa Mattina
- Department of Biomedical and Biotechnological Sciences, University of Catania, Italy
| | - Gabriele Trimarchi
- Department of Biomedical and Biotechnological Sciences, University of Catania, Italy
| | - Giovanna Capolongo
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Mariadelina Simeoni
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Alessandra F. Perna
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Miriam Zacchia
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | | | - Rosa M. Pollastro
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Francesco Rapisarda
- School of Nephrology, Department of Clinical and Experimental Medicine, University of Catania, Italy
| | - Giovambattista Capasso
- Biogem Research Institute, Ariano Irpino, Italy
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
| | - Francesco Trepiccione
- Biogem Research Institute, Ariano Irpino, Italy
- Department of Translational Medical Sciences, University of Campania "L. Vanvitelli", Naples, Italy
- Address correspondence to:Francesco Trepiccione, Department of Translational Medical Sciences University of Campania "L.Vanvitelli", Via Pansini n5, 80131 Naples, Italy. E-mail:
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9
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Warnecke A, Giesemann A. Embryology, Malformations, and Rare Diseases of the Cochlea. Laryngorhinootologie 2021; 100:S1-S43. [PMID: 34352899 PMCID: PMC8354575 DOI: 10.1055/a-1349-3824] [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] [Indexed: 01/19/2023]
Abstract
Despite the low overall prevalence of individual rare diseases, cochlear
dysfunction leading to hearing loss represents a symptom in a large
proportion. The aim of this work was to provide a clear overview of rare
cochlear diseases, taking into account the embryonic development of the
cochlea and the systematic presentation of the different disorders. Although
rapid biotechnological and bioinformatic advances may facilitate the
diagnosis of a rare disease, an interdisciplinary exchange is often required
to raise the suspicion of a rare disease. It is important to recognize that
the phenotype of rare inner ear diseases can vary greatly not only in
non-syndromic but also in syndromic hearing disorders. Finally, it becomes
clear that the phenotype of the individual rare diseases cannot be
determined exclusively by classical genetics even in monogenetic
disorders.
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Affiliation(s)
- Athanasia Warnecke
- Klinik für Hals-, Nasen- und Ohrenheilkunde, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover.,Deutsche Forschungsgemeinschaft Exzellenzcluster"Hearing4all" - EXC 2177/1 - Project ID 390895286
| | - Anja Giesemann
- Institut für Neuroradiologie, Medizinische Hochschule Hannover, Carl-Neuberg-Straße 1, 30625 Hannover
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10
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Hanna RM, Ahdoot RS, Kalantar-Zadeh K, Ghobry L, Kurtz I. Calcium Transport in the Kidney and Disease Processes. Front Endocrinol (Lausanne) 2021; 12:762130. [PMID: 35299844 PMCID: PMC8922474 DOI: 10.3389/fendo.2021.762130] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Accepted: 11/25/2021] [Indexed: 11/25/2022] Open
Abstract
Calcium is a key ion involved in cardiac and skeletal muscle contractility, nerve function, and skeletal structure. Global calcium balance is affected by parathyroid hormone and vitamin D, and calcium is shuttled between the extracellular space and the bone matrix compartment dynamically. The kidney plays an important role in whole-body calcium balance. Abnormalities in the kidney transport proteins alter the renal excretion of calcium. Various hormonal and regulatory pathways have evolved that regulate the renal handling of calcium to maintain the serum calcium within defined limits despite dynamic changes in dietary calcium intake. Dysregulation of renal calcium transport can occur pharmacologically, hormonally, and via genetic mutations in key proteins in various nephron segments resulting in several disease processes. This review focuses on the regulation transport of calcium in the nephron. Genetic diseases affecting the renal handling of calcium that can potentially lead to changes in the serum calcium concentration are reviewed.
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Affiliation(s)
- Ramy M. Hanna
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
- *Correspondence: Ramy M. Hanna,
| | - Rebecca S. Ahdoot
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
| | - Kamyar Kalantar-Zadeh
- Division of Nephrology, Department of Medicine, University of California Irvine (UCI) School of Medicine, Orange, CA, United States
| | - Lena Ghobry
- School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - Ira Kurtz
- Division of Nephrology, Department of Medicine, David Geffen School of Medicine, University of California Los Angeles (UCLA), Los Angeles, CA, United States
- University of California Los Angeles (UCLA) Brain Research Center, Los Angeles, CA, United States
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11
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Smith KE, Murphy P, Jagger DJ. Divergent membrane properties of mouse cochlear glial cells around hearing onset. J Neurosci Res 2020; 99:679-698. [PMID: 33099767 DOI: 10.1002/jnr.24744] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 09/21/2020] [Accepted: 10/05/2020] [Indexed: 11/11/2022]
Abstract
Spiral ganglion neurons (SGNs) are the primary afferent neurons of the auditory system, and together with their attendant glia, form the auditory nerve. Within the cochlea, satellite glial cells (SGCs) encapsulate the cell body of SGNs, whereas Schwann cells (SCs) wrap their peripherally- and centrally-directed neurites. Despite their likely importance in auditory nerve function and homeostasis, the physiological properties of auditory glial cells have evaded description. Here, we characterized the voltage-activated membrane currents of glial cells from the mouse cochlea. We identified a prominent weak inwardly rectifying current in SGCs within cochlear slice preparations (postnatal day P5-P6), which was also present in presumptive SGCs within dissociated cultures prepared from the cochleae of hearing mice (P14-P15). Pharmacological block by Ba2+ and desipramine suggested that channels belonging to the Kir4 family mediated the weak inwardly rectifying current, and post hoc immunofluorescence implicated the involvement of Kir4.1 subunits. Additional electrophysiological profiles were identified for glial cells within dissociated cultures, suggesting that glial subtypes may have specific membrane properties to support distinct physiological roles. Immunofluorescence using fixed cochlear sections revealed that although Kir4.1 is restricted to SGCs after the onset of hearing, these channels are more widely distributed within the glial population earlier in postnatal development (i.e., within both SGCs and SCs). The decrease in Kir4.1 immunofluorescence during SC maturation was coincident with a reduction of Sox2 expression and advancing neurite myelination. The data suggest a diversification of glial properties occurs in preparation for sound-driven activity in the auditory nerve.
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Affiliation(s)
- Katie E Smith
- UCL Ear Institute, University College London, London, UK
| | - Phoebe Murphy
- UCL Ear Institute, University College London, London, UK
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12
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Bhowmick SS, Lang AE. Movement Disorders and Renal Diseases. Mov Disord Clin Pract 2020; 7:763-779. [PMID: 33043074 DOI: 10.1002/mdc3.13005] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/03/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023] Open
Abstract
Movement disorders often emerge from the interplay of complex pathophysiological processes involving the kidneys and the nervous system. Tremor, myoclonus, ataxia, chorea, and parkinsonism can occur in the context of renal dysfunction (azotemia and electrolyte abnormalities) or they can be part of complications of its management (dialysis and renal transplantation). On the other hand, myoglobinuria from rhabdomyolysis in status dystonicus and certain drugs used in the management of movement disorders can cause nephrotoxicity. Distinct from these well-recognized associations, it is important to appreciate that there are several inherited and acquired disorders in which movement abnormalities do not occur as a consequence of renal dysfunction or vice versa but are manifestations of common pathophysiological processes affecting the nervous system and the kidneys. These disorders are the emphasis of this review. Increasing awareness of these conditions among neurologists may help them to identify renal involvement earlier, take timely intervention by anticipating complications and focus on therapies targeting common mechanisms in addition to symptomatic management of movement disorders. Recognition of renal impairment in a patient with complex neurological presentation may narrow down the differentials and aid in reaching a definite diagnosis.
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Affiliation(s)
- Suvorit S Bhowmick
- Division of Neurology, Department of Medicine, Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson's Disease, Toronto Western Hospital University Health Network Toronto Ontario Canada
| | - Anthony E Lang
- Division of Neurology, Department of Medicine, Morton and Gloria Shulman Movement Disorders Clinic and the Edmond J. Safra Program in Parkinson's Disease, Toronto Western Hospital University Health Network Toronto Ontario Canada
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Cozzolino O, Sicca F, Paoli E, Trovato F, Santorelli FM, Ratto GM, Marchese M. Evolution of Epileptiform Activity in Zebrafish by Statistical-Based Integration of Electrophysiology and 2-Photon Ca 2+ Imaging. Cells 2020; 9:cells9030769. [PMID: 32245158 PMCID: PMC7140665 DOI: 10.3390/cells9030769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Revised: 03/14/2020] [Accepted: 03/18/2020] [Indexed: 12/20/2022] Open
Abstract
The study of sources and spatiotemporal evolution of ictal bursts is critical for the mechanistic understanding of epilepsy and for the validation of anti-epileptic drugs. Zebrafish is a powerful vertebrate model representing an excellent compromise between system complexity and experimental accessibility. We performed the quantitative evaluation of the spatial recruitment of neuronal populations during physiological and pathological activity by combining local field potential (LFP) recordings with simultaneous 2-photon Ca2+ imaging. We developed a method to extract and quantify electrophysiological transients coupled with Ca2+ events and we applied this tool to analyze two different epilepsy models and to assess the efficacy of the anti-epileptic drug valproate. Finally, by cross correlating the imaging data with the LFP, we demonstrated that the cerebellum is the main source of epileptiform transients. We have also shown that each transient was preceded by the activation of a sparse subset of neurons mostly located in the optic tectum.
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Affiliation(s)
- Olga Cozzolino
- National Enterprise for Nanoscience and Nanotechnology (NEST), Istituto Nanoscienze Consiglio Nazionale delle Ricerche (CNR) and Scuola Normale Superiore Pisa, 56127 Pisa, Italy; (O.C.); (E.P.); (F.T.)
| | - Federico Sicca
- Molecular Medicine, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56028 Pisa, Italy; (F.S.); (F.M.S.)
| | - Emanuele Paoli
- National Enterprise for Nanoscience and Nanotechnology (NEST), Istituto Nanoscienze Consiglio Nazionale delle Ricerche (CNR) and Scuola Normale Superiore Pisa, 56127 Pisa, Italy; (O.C.); (E.P.); (F.T.)
| | - Francesco Trovato
- National Enterprise for Nanoscience and Nanotechnology (NEST), Istituto Nanoscienze Consiglio Nazionale delle Ricerche (CNR) and Scuola Normale Superiore Pisa, 56127 Pisa, Italy; (O.C.); (E.P.); (F.T.)
| | - Filippo M. Santorelli
- Molecular Medicine, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56028 Pisa, Italy; (F.S.); (F.M.S.)
| | - Gian Michele Ratto
- National Enterprise for Nanoscience and Nanotechnology (NEST), Istituto Nanoscienze Consiglio Nazionale delle Ricerche (CNR) and Scuola Normale Superiore Pisa, 56127 Pisa, Italy; (O.C.); (E.P.); (F.T.)
- Correspondence: (G.M.R.); (M.M.); Tel.: +39-050-3153168 (G.M.R.); +39-050-886332 (M.M.)
| | - Maria Marchese
- Molecular Medicine, IRCCS Fondazione Stella Maris, Via dei Giacinti 2, 56028 Pisa, Italy; (F.S.); (F.M.S.)
- Correspondence: (G.M.R.); (M.M.); Tel.: +39-050-3153168 (G.M.R.); +39-050-886332 (M.M.)
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14
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MacAulay N. Molecular mechanisms of K + clearance and extracellular space shrinkage-Glia cells as the stars. Glia 2020; 68:2192-2211. [PMID: 32181522 DOI: 10.1002/glia.23824] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 12/17/2022]
Abstract
Neuronal signaling in the central nervous system (CNS) associates with release of K+ into the extracellular space resulting in transient increases in [K+ ]o . This elevated K+ is swiftly removed, in part, via uptake by neighboring glia cells. This process occurs in parallel to the [K+ ]o elevation and glia cells thus act as K+ sinks during the neuronal activity, while releasing it at the termination of the pulse. The molecular transport mechanisms governing this glial K+ absorption remain a point of debate. Passive distribution of K+ via Kir4.1-mediated spatial buffering of K+ has become a favorite within the glial field, although evidence for a quantitatively significant contribution from this ion channel to K+ clearance from the extracellular space is sparse. The Na+ /K+ -ATPase, but not the Na+ /K+ /Cl- cotransporter, NKCC1, shapes the activity-evoked K+ transient. The different isoform combinations of the Na+ /K+ -ATPase expressed in glia cells and neurons display different kinetic characteristics and are thereby distinctly geared toward their temporal and quantitative contribution to K+ clearance. The glia cell swelling occurring with the K+ transient was long assumed to be directly associated with K+ uptake and/or AQP4, although accumulating evidence suggests that they are not. Rather, activation of bicarbonate- and lactate transporters appear to lead to glial cell swelling via the activity-evoked alkaline transient, K+ -mediated glial depolarization, and metabolic demand. This review covers evidence, or lack thereof, accumulated over the last half century on the molecular mechanisms supporting activity-evoked K+ and extracellular space dynamics.
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Affiliation(s)
- Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
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15
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Morin M, Forst AL, Pérez-Torre P, Jiménez-Escrig A, Barca-Tierno V, García-Galloway E, Warth R, Lopez-Sendón Moreno JL, Moreno-Pelayo MA. Novel mutations in the KCNJ10 gene associated to a distinctive ataxia, sensorineural hearing loss and spasticity clinical phenotype. Neurogenetics 2020; 21:135-143. [PMID: 32062759 DOI: 10.1007/s10048-020-00605-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 02/01/2020] [Indexed: 12/31/2022]
Abstract
KCNJ10 encodes the inward-rectifying potassium channel (Kir4.1) that is expressed in the brain, inner ear, and kidney. Loss-of-function mutations in KCNJ10 gene cause a complex syndrome consisting of epilepsy, ataxia, intellectual disability, sensorineural deafness, and tubulopathy (EAST/SeSAME syndrome). Patients with EAST/SeSAME syndrome display renal salt wasting and electrolyte imbalance that resemble the clinical features of impaired distal tubular salt transport in Gitelman's syndrome. A key distinguishing feature between these two conditions is the additional neurological (extrarenal) manifestations found in EAST/SeSAME syndrome. Recent reports have further expanded the clinical and mutational spectrum of KCNJ10-related disorders including non-syndromic early-onset cerebellar ataxia. Here, we describe a kindred of three affected siblings with early-onset ataxia, deafness, and progressive spasticity without other prominent clinical features. By using targeted next-generation sequencing, we have identified two novel missense variants, c.488G>A (p.G163D) and c.512G>A (p.R171Q), in the KCNJ10 gene that, in compound heterozygosis, cause this distinctive EAST/SeSAME phenotype in our family. Electrophysiological characterization of these two variants confirmed their pathogenicity. When expressed in CHO cells, the R171Q mutation resulted in 50% reduction of currents compared to wild-type KCNJ10 and G163D showed a complete loss of function. Co-expression of G163D and R171Q had a more pronounced effect on currents and membrane potential than R171Q alone but less severe than single expression of G163D. Moreover, the effect of the mutations seemed less pronounced in the presence of Kir5.1 (encoded by KCNJ16), with whom the renal Kir4.1 channels form heteromers. This partial functional rescue by co-expression with Kir5.1 might explain the lack of renal symptoms in the patients. This report illustrates that a spectrum of disorders with distinct clinical symptoms may result from mutations in different parts of KCNJ10, a gene initially associated only with the EAST/SeSAME syndrome.
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Affiliation(s)
- Matias Morin
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain
| | - Anna-Lena Forst
- Medical Cell Biology, University of Regensburg, 93053, Regensburg, Germany
| | - Paula Pérez-Torre
- Servicio de Neurología, Hospital Universitario Ramón y Cajal, 28034, Madrid, Spain
| | | | - Verónica Barca-Tierno
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain
| | - Eva García-Galloway
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain
| | - Richard Warth
- Medical Cell Biology, University of Regensburg, 93053, Regensburg, Germany
| | | | - Miguel Angel Moreno-Pelayo
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS) and Hospital Universitario Ramón y Cajal, CIBERER, 28034, Madrid, Spain.
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16
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Papandreou A, Danti FR, Spaull R, Leuzzi V, Mctague A, Kurian MA. The expanding spectrum of movement disorders in genetic epilepsies. Dev Med Child Neurol 2020; 62:178-191. [PMID: 31784983 DOI: 10.1111/dmcn.14407] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/01/2019] [Indexed: 12/27/2022]
Abstract
An ever-increasing number of neurogenetic conditions presenting with both epilepsy and atypical movements are now recognized. These disorders within the 'genetic epilepsy-dyskinesia' spectrum are clinically and genetically heterogeneous. Increased clinical awareness is therefore necessary for a rational diagnostic approach. Furthermore, careful interpretation of genetic results is key to establishing the correct diagnosis and initiating disease-specific management strategies in a timely fashion. In this review we describe the spectrum of movement disorders associated with genetically determined epilepsies. We also propose diagnostic strategies and putative pathogenic mechanisms causing these complex syndromes associated with both seizures and atypical motor control. WHAT THIS PAPER ADDS: Implicated genes encode proteins with very diverse functions. Pathophysiological mechanisms by which epilepsy and movement disorder phenotypes manifest are often not clear. Early diagnosis of treatable disorders is essential and next generation sequencing may be required.
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Affiliation(s)
- Apostolos Papandreou
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Federica Rachele Danti
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Robert Spaull
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, UK
- Bristol Medical School, University of Bristol, Bristol, UK
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, Unit of Child Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy
| | - Amy Mctague
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Manju A Kurian
- Molecular Neurosciences, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital, London, UK
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17
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Zangerl-Plessl EM, Qile M, Bloothooft M, Stary-Weinzinger A, van der Heyden MAG. Disease Associated Mutations in K IR Proteins Linked to Aberrant Inward Rectifier Channel Trafficking. Biomolecules 2019; 9:biom9110650. [PMID: 31731488 PMCID: PMC6920955 DOI: 10.3390/biom9110650] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/22/2019] [Accepted: 10/23/2019] [Indexed: 12/28/2022] Open
Abstract
The ubiquitously expressed family of inward rectifier potassium (KIR) channels, encoded by KCNJ genes, is primarily involved in cell excitability and potassium homeostasis. Channel mutations associate with a variety of severe human diseases and syndromes, affecting many organ systems including the central and peripheral neural system, heart, kidney, pancreas, and skeletal muscle. A number of mutations associate with altered ion channel expression at the plasma membrane, which might result from defective channel trafficking. Trafficking involves cellular processes that transport ion channels to and from their place of function. By alignment of all KIR channels, and depicting the trafficking associated mutations, three mutational hotspots were identified. One localized in the transmembrane-domain 1 and immediately adjacent sequences, one was found in the G-loop and Golgi-export domain, and the third one was detected at the immunoglobulin-like domain. Surprisingly, only few mutations were observed in experimentally determined Endoplasmic Reticulum (ER)exit-, export-, or ER-retention motifs. Structural mapping of the trafficking defect causing mutations provided a 3D framework, which indicates that trafficking deficient mutations form clusters. These “mutation clusters” affect trafficking by different mechanisms, including protein stability.
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Affiliation(s)
- Eva-Maria Zangerl-Plessl
- Department of Pharmacology and Toxicology, University of Vienna, 1090 Vienna, Austria; (E.-M.Z.-P.); (A.S.-W.)
| | - Muge Qile
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 CM Utrecht, The Netherlands; (M.Q.); (M.B.)
| | - Meye Bloothooft
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 CM Utrecht, The Netherlands; (M.Q.); (M.B.)
| | - Anna Stary-Weinzinger
- Department of Pharmacology and Toxicology, University of Vienna, 1090 Vienna, Austria; (E.-M.Z.-P.); (A.S.-W.)
| | - Marcel A. G. van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, 3584 CM Utrecht, The Netherlands; (M.Q.); (M.B.)
- Correspondence: ; Tel.: +31-887558901
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18
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van der Wijst J, Belge H, Bindels RJM, Devuyst O. Learning Physiology From Inherited Kidney Disorders. Physiol Rev 2019; 99:1575-1653. [PMID: 31215303 DOI: 10.1152/physrev.00008.2018] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The identification of genes causing inherited kidney diseases yielded crucial insights in the molecular basis of disease and improved our understanding of physiological processes that operate in the kidney. Monogenic kidney disorders are caused by mutations in genes coding for a large variety of proteins including receptors, channels and transporters, enzymes, transcription factors, and structural components, operating in specialized cell types that perform highly regulated homeostatic functions. Common variants in some of these genes are also associated with complex traits, as evidenced by genome-wide association studies in the general population. In this review, we discuss how the molecular genetics of inherited disorders affecting different tubular segments of the nephron improved our understanding of various transport processes and of their involvement in homeostasis, while providing novel therapeutic targets. These include inherited disorders causing a dysfunction of the proximal tubule (renal Fanconi syndrome), with emphasis on epithelial differentiation and receptor-mediated endocytosis, or affecting the reabsorption of glucose, the handling of uric acid, and the reabsorption of sodium, calcium, and magnesium along the kidney tubule.
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Affiliation(s)
- Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Hendrica Belge
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
| | - Olivier Devuyst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center , Nijmegen , The Netherlands ; Institute of Physiology, University of Zurich , Zurich , Switzerland ; and Division of Nephrology, Institute of Experimental and Clinical Research (IREC), Medical School, Université catholique de Louvain, Brussels, Belgium
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19
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Calhoun JD, Carvill GL. Unravelling the genetic architecture of autosomal recessive epilepsy in the genomic era. J Neurogenet 2018; 32:295-312. [PMID: 30247086 DOI: 10.1080/01677063.2018.1513509] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The technological advancement of next-generation sequencing has greatly accelerated the pace of variant discovery in epilepsy. Despite an initial focus on autosomal dominant epilepsy due to the tractable nature of variant discovery with trios under a de novo model, more and more variants are being reported in families with epilepsies consistent with autosomal recessive (AR) inheritance. In this review, we touch on the classical AR epilepsy variants such as the inborn errors of metabolism and malformations of cortical development. However, we also highlight recently reported genes that are being identified by next-generation sequencing approaches and online 'matchmaking' platforms. Syndromes mainly characterized by seizures and complex neurodevelopmental disorders comorbid with epilepsy are discussed as an example of the wide phenotypic spectrum associated with the AR epilepsies. We conclude with a foray into the future, from the application of whole-genome sequencing to identify elusive epilepsy variants, to the promise of precision medicine initiatives to provide novel targeted therapeutics specific to the individual based on their clinical genetic testing.
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Affiliation(s)
- Jeffrey D Calhoun
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
| | - Gemma L Carvill
- a Department of Neurology , Northwestern University Feinberg School of Medicine , Chicago , IL , USA
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20
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Deneysel epilepsi modelinde böbrekte bulunan aquaporin4 ve aquaporin2 kanallarının gen ekspresyonları. JOURNAL OF CONTEMPORARY MEDICINE 2018. [DOI: 10.16899/gopctd.441193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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21
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Celmina M, Micule I, Inashkina I, Audere M, Kuske S, Pereca J, Stavusis J, Pelnena D, Strautmanis J. EAST/SeSAME syndrome: Review of the literature and introduction of four new Latvian patients. Clin Genet 2018; 95:63-78. [PMID: 29722015 DOI: 10.1111/cge.13374] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Revised: 04/12/2018] [Accepted: 04/23/2018] [Indexed: 11/28/2022]
Abstract
EAST (Epilepsy, Ataxia, Sensorineural deafness, Tubulopathy) or SeSAME (Seizures, Sensorineural deafness, Ataxia, Mental retardation, and Electrolyte imbalance) syndrome is a rare autosomal recessive syndrome first described in 2009 independently by Bockenhauer and Scholl. It is caused by mutations in KCNJ10, which encodes Kir4.1, an inwardly rectifying K+ channel found in the brain, inner ear, kidney and eye. To date, 16 mutations and at least 28 patients have been reported. In this paper, we review mutations causing EAST/SeSAME syndrome, clinical manifestations in detail, and efficacy of treatment in previously reported patients. We also report a new Latvian kindred with 4 patients. In contrast to the majority of previous reports, we found a progressive course of the disorder in terms of hearing impairment and neurologic deficit. The treatment is based on antiepileptic drugs, electrolyte replacement, hearing aids and mobility devices. Future research should concentrate on recognizing the lesions in the central nervous system to evaluate new potential diagnostic criteria and on formally evaluating intellectual disability.
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Affiliation(s)
- M Celmina
- Clinic for Pediatrics, Children's Clinical University Hospital, Riga, Latvia.,Faculty of Continuing Education, University of Latvia, Riga, Latvia
| | - I Micule
- Clinic for Medical Genetics and Prenatal Diagnostics, Children's Clinical University Hospital, Riga, Latvia
| | - I Inashkina
- Latvian Biomedical Research and Study Center, Riga, Latvia
| | - M Audere
- ENT Department, Children's Clinical University Hospital, Riga, Latvia
| | - S Kuske
- Latvian Children's Hearing Center, Riga, Latvia
| | - J Pereca
- Emergency Department, Royal Infirmary of Edinburg, Edinburgh, United Kingdom
| | - J Stavusis
- Latvian Biomedical Research and Study Center, Riga, Latvia
| | - D Pelnena
- Latvian Biomedical Research and Study Center, Riga, Latvia
| | - J Strautmanis
- Clinic for Pediatric Neurology and Neurosurgery, Children's Clinical University Hospital, Riga, Latvia
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22
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Unusual white matter involvement in EAST syndrome associated with novel KCNJ10 mutations. J Neurol 2018; 265:1419-1425. [PMID: 29666984 DOI: 10.1007/s00415-018-8826-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 03/05/2018] [Accepted: 03/08/2018] [Indexed: 01/06/2023]
Abstract
BACKGROUND Epilepsy, ataxia, sensorineural deafness, and tubulopathy (EAST syndrome) is a rare channelopathy due to KCNJ10 mutations. So far, only mild cerebellar hypoplasia and/or dentate nuclei abnormalities have been reported as major neuroimaging findings in these patients. METHODS We analyzed the clinical and brain MRI features of two unrelated patients (aged 27 and 23 years) with EAST syndrome carrying novel homozygous frameshift mutations (p.Asn232Glnfs*14and p.Gly275Valfs*7) in KCNJ10, detected by whole exome sequencing. RESULTS Brain MRI examinations at 8 years in Patient 1 and at 13 years in Patient 2 revealed a peculiar brain and spinal cord involvement characterized by restricted diffusion of globi pallidi, thalami, brainstem, dentate nuclei, and cervical spinal cord in keeping with intramyelinic edema. The follow-up studies, performed, respectively, after 19 and 10 years, showed mild cerebellar atrophy and slight progression of the brain and spinal cord T2 signal abnormalities with increase of the restricted diffusion in the affected regions. CONCLUSION The present cases harboring novel homozygous frameshift mutations in KCNJ10 expand the spectrum of brain abnormalities in EAST syndrome, including mild cerebellar atrophy and intramyelinic edema, resulting from abnormal function of the Kir4.1 inwardly rectifying potassium channel at the astrocyte endfeet, with disruption of water-ion homeostasis.
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23
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Kleta R, Bockenhauer D. Salt-Losing Tubulopathies in Children: What's New, What's Controversial? J Am Soc Nephrol 2018; 29:727-739. [PMID: 29237739 PMCID: PMC5827598 DOI: 10.1681/asn.2017060600] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Renal tubulopathies provide insights into the inner workings of the kidney, yet also pose therapeutic challenges. Because of the central nature of sodium in tubular transport physiology, disorders of sodium handling may affect virtually all aspects of the homeostatic functions of the kidney. Yet, owing to the rarity of these disorders, little clinical evidence regarding treatment exists. Consequently, treatment can vary widely between individual physicians and centers and is based mainly on understanding of renal physiology, reported clinical observations, and individual experiences. Salt-losing tubulopathies can affect all tubular segments, from the proximal tubule to the collecting duct. But the more frequently observed disorders are Bartter and Gitelman syndrome, which affect salt transport in the thick ascending limb of Henle's loop and/or the distal convoluted tubule, and these disorders generate the greatest controversies regarding management. Here, we review clinical and molecular aspects of salt-losing tubulopathies and discuss novel insights provided mainly by genetic investigations and retrospective clinical reviews. Additionally, we discuss controversial topics in the management of these disorders to highlight areas of importance for future clinical trials. International collaboration will be required to perform clinical studies to inform the treatment of these rare disorders.
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Affiliation(s)
- Robert Kleta
- UCL Centre for Nephrology and Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
| | - Detlef Bockenhauer
- UCL Centre for Nephrology and Great Ormond Street Hospital NHS Foundation Trust, London, United Kingdom
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24
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Nicita F, Tasca G, Nardella M, Bellacchio E, Camponeschi I, Vasco G, Schirinzi T, Bertini E, Zanni G. Novel Homozygous KCNJ10 Mutation in a Patient with Non-syndromic Early-Onset Cerebellar Ataxia. THE CEREBELLUM 2018; 17:499-503. [DOI: 10.1007/s12311-018-0924-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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25
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Zacchia M, Capolongo G, Rinaldi L, Capasso G. The importance of the thick ascending limb of Henle's loop in renal physiology and pathophysiology. Int J Nephrol Renovasc Dis 2018; 11:81-92. [PMID: 29497325 PMCID: PMC5818843 DOI: 10.2147/ijnrd.s154000] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The thick ascending limb (TAL) of Henle’s loop is a crucial segment for many tasks of the nephron. Indeed, the TAL is not only a mainstay for reabsorption of sodium (Na+), potassium (K+), and divalent cations such as calcium (Ca2+) and magnesium (Mg2+) from the luminal fluid, but also has an important role in urine concentration, overall acid–base homeostasis, and ammonia cycle. Transcellular Na+ transport along the TAL is a prerequisite for Na+, K+, Ca2+, Mg2+ homeostasis, and water reabsorption, the latter through its contribution in the generation of the cortico-medullar osmotic gradient. The role of this nephron site in acid–base balance, via bicarbonate reabsorption and acid secretion, is sometimes misunderstood by clinicians. This review describes in detail these functions, reporting in addition to the well-known molecular mechanisms, some novel findings from the current literature; moreover, the pathophysiology and the clinical relevance of primary or acquired conditions caused by TAL dysfunction are discussed. Knowing the physiology of the TAL is fundamental for clinicians, for a better understanding and management of rare and common conditions, such as tubulopathies, hypertension, and loop diuretics abuse.
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Affiliation(s)
- Miriam Zacchia
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
| | - Giovanna Capolongo
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
| | - Luca Rinaldi
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
| | - Giovambattista Capasso
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
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Al Dhaibani MA, El-Hattab AW, Holroyd KB, Orthmann-Murphy J, Larson VA, Siddiqui KA, Szolics M, Schiess N. Novel mutation in the KCNJ10 gene in three siblings with seizures, ataxia and no electrolyte abnormalities. J Neurogenet 2017; 32:1-5. [PMID: 29191078 DOI: 10.1080/01677063.2017.1404057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We report a consanguineous family with three affected siblings with novel mutation in the KCNJ10 gene. All three presented with central nervous system symptoms in the form of infantile focal seizures, ataxia, slurred speech with early developmental delay and intellectual disability in two siblings. None had any associated electrolyte abnormalities and no symptomatic hearing deficits were observed.
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Affiliation(s)
- Muna A Al Dhaibani
- a Department of Pediatrics , Tawam Hospital , Al Ain , United Arab Emirates
| | - Ayman W El-Hattab
- b Division of Clinical Genetics and Metabolic Disorders Pediatrics Department , Tawam Hospital , Al Ain , United Arab Emirates
| | | | | | - Valerie A Larson
- d Johns Hopkins Hospital and Health System , Baltimore , MD , USA
| | | | - Miklos Szolics
- f Department of Neurology , Al Tawam Hospital , Al Ain , United Arab Emirates
| | - Nicoline Schiess
- g Department of Neurology , Johns Hopkins University , Baltimore , MD , USA
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Khakh BS, Beaumont V, Cachope R, Munoz-Sanjuan I, Goldman SA, Grantyn R. Unravelling and Exploiting Astrocyte Dysfunction in Huntington's Disease. Trends Neurosci 2017; 40:422-437. [PMID: 28578789 PMCID: PMC5706770 DOI: 10.1016/j.tins.2017.05.002] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 04/24/2017] [Accepted: 05/01/2017] [Indexed: 01/02/2023]
Abstract
Astrocytes are abundant within mature neural circuits and are involved in brain disorders. Here, we summarize our current understanding of astrocytes and Huntington's disease (HD), with a focus on correlative and causative dysfunctions of ion homeostasis, calcium signaling, and neurotransmitter clearance, as well as on the use of transplanted astrocytes to produce therapeutic benefit in mouse models of HD. Overall, the data suggest that astrocyte dysfunction is an important contributor to the onset and progression of some HD symptoms in mice. Additional exploration of astrocytes in HD mouse models and humans is needed and may provide new therapeutic opportunities to explore in conjunction with neuronal rescue and repair strategies.
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Affiliation(s)
- Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA; Neurobiology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095-1751, USA.
| | - Vahri Beaumont
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, CA 90045, USA
| | - Roger Cachope
- CHDI Management/CHDI Foundation, 6080 Center Drive, Los Angeles, CA 90045, USA
| | | | - Steven A Goldman
- Center for Translational Neuromedicine, University of Rochester, Rochester, NY 14642, USA; Center for Neuroscience, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Rosemarie Grantyn
- Exzellenzcluster NeuroCure & Abt. Experimentelle Neurologie, Charité - Universitätsmedizin Berlin, Robert-Koch-Platz 4, D-10115 Berlin, Germany
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A Missense Variant in KCNJ10 in Belgian Shepherd Dogs Affected by Spongy Degeneration with Cerebellar Ataxia (SDCA1). G3-GENES GENOMES GENETICS 2017; 7:663-669. [PMID: 28007838 PMCID: PMC5295610 DOI: 10.1534/g3.116.038455] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Spongy degeneration with cerebellar ataxia (SDCA) is a severe neurodegenerative disease with monogenic autosomal recessive inheritance in Malinois dogs, one of the four varieties of the Belgian Shepherd breed. We performed a genetic investigation in six families and seven isolated cases of Malinois dogs with signs of cerebellar dysfunction. Linkage analysis revealed an unexpected genetic heterogeneity within the studied cases. The affected dogs from four families and one isolated case shared a ∼1.4 Mb common homozygous haplotype segment on chromosome 38. Whole genome sequence analysis of three affected and 140 control dogs revealed a missense variant in the KCNJ10 gene encoding a potassium channel (c.986T>C; p.Leu329Pro). Pathogenic variants in KCNJ10 were reported previously in humans, mice, and dogs with neurological phenotypes. Therefore, we consider KCNJ10:c.986T>C the most likely candidate causative variant for one subtype of SDCA in Malinois dogs, which we propose to term spongy degeneration with cerebellar ataxia 1 (SDCA1). However, our study also comprised samples from 12 Malinois dogs with cerebellar dysfunction which were not homozygous for this variant, suggesting a different genetic basis in these dogs. A retrospective detailed clinical and histopathological analysis revealed subtle neuropathological differences with respect to SDCA1-affected dogs. Thus, our study highlights the genetic and phenotypic complexity underlying cerebellar dysfunction in Malinois dogs and provides the basis for a genetic test to eradicate one specific neurodegenerative disease from the breeding population. These dogs represent an animal model for the human EAST syndrome.
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