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Martin CA, Sheppard EC, Ali HAA, Illera JC, Suh A, Spurgin LG, Richardson DS. Genomic landscapes of divergence among island bird populations: Evidence of parallel adaptation but at different loci? Mol Ecol 2024; 33:e17365. [PMID: 38733214 DOI: 10.1111/mec.17365] [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: 02/26/2023] [Accepted: 03/01/2024] [Indexed: 05/13/2024]
Abstract
When populations colonise new environments, they may be exposed to novel selection pressures but also suffer from extensive genetic drift due to founder effects, small population sizes and limited interpopulation gene flow. Genomic approaches enable us to study how these factors drive divergence, and disentangle neutral effects from differentiation at specific loci due to selection. Here, we investigate patterns of genetic diversity and divergence using whole-genome resequencing (>22× coverage) in Berthelot's pipit (Anthus berthelotii), a passerine endemic to the islands of three north Atlantic archipelagos. Strong environmental gradients, including in pathogen pressure, across populations in the species range, make it an excellent system in which to explore traits important in adaptation and/or incipient speciation. First, we quantify how genomic divergence accumulates across the speciation continuum, that is, among Berthelot's pipit populations, between sub species across archipelagos, and between Berthelot's pipit and its mainland ancestor, the tawny pipit (Anthus campestris). Across these colonisation timeframes (2.1 million-ca. 8000 years ago), we identify highly differentiated loci within genomic islands of divergence and conclude that the observed distributions align with expectations for non-neutral divergence. Characteristic signatures of selection are identified in loci associated with craniofacial/bone and eye development, metabolism and immune response between population comparisons. Interestingly, we find limited evidence for repeated divergence of the same loci across the colonisation range but do identify different loci putatively associated with the same biological traits in different populations, likely due to parallel adaptation. Incipient speciation across these island populations, in which founder effects and selective pressures are strong, may therefore be repeatedly associated with morphology, metabolism and immune defence.
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Affiliation(s)
- Claudia A Martin
- School of Biological Sciences, University of East Anglia, Norfolk, UK
- Terrestrial Ecology Unit, Biology Department, Ghent University, Ghent, Belgium
- School of Biological Sciences, The University of Edinburgh, Edinburgh, UK
| | | | - Hisham A A Ali
- Department of Biology, Edward Grey Institute of Field Ornithology, University of Oxford, Oxford, UK
| | - Juan Carlos Illera
- Biodiversity Research Institute (CSIC-Oviedo University-Principality of Asturias), University of Oviedo, Mieres, Asturias, Spain
| | - Alexander Suh
- School of Biological Sciences, University of East Anglia, Norfolk, UK
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre (EBC), Science for Life Laboratory, Uppsala University, Uppsala, Sweden
| | - Lewis G Spurgin
- School of Biological Sciences, University of East Anglia, Norfolk, UK
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Scalone EJ, Triplett AD. A Case of Respiratory Distress in a Newborn. Clin Pediatr (Phila) 2024:99228241240194. [PMID: 38515020 DOI: 10.1177/00099228241240194] [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: 03/23/2024]
Affiliation(s)
- Eleanor J Scalone
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Andrea D Triplett
- Department of Pediatrics, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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Cui F, Wulan T, Zhang Q, Zhang VW, Jiang Y. Identification of a novel KCNT2 variant in a family with developmental and epileptic encephalopathies: a case report and literature review. Front Genet 2024; 15:1371282. [PMID: 38510274 PMCID: PMC10951377 DOI: 10.3389/fgene.2024.1371282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 02/20/2024] [Indexed: 03/22/2024] Open
Abstract
Background: Developmental and epileptic encephalopathies (DEEs) are a group of heterogeneous neurodevelopmental diseases characterized mainly by developmental delay/intellectual disability and early-onset epilepsy. Researchers have identified variations in the KCNT2 gene (OMIM* 610044) as the cause of DEE type 57 (MIM# 617771). Case presentation: We report in this study a 46-year-old woman who presented with early-onset epilepsy, intellectual disability, hypertrichosis, coarse facial features, and short stature. Besides, there were four other affected individuals in her family history, including two elder brothers, a younger brother, and their mother. We collected blood samples from the proband, her two affected brothers, and her clinically normal daughter for genetic analysis. Clinical exome sequencing revealed a novel heterozygous variant in the KCNT2 gene (NM_198503: c.188G>A, p.Arg63His) in the proband and her two affected brothers, while her daughter did not carry this variant. Furthermore, we reviewed all 25 patients identified in the literature with KCNT2 variants and compared their phenotypes. Conclusion: Epilepsy and intellectual disability/developmental delay occur in almost all patients with KCNT2 variants. KCNT2-relevant DEEs partially overlap with the clinical phenotypes of KATP channel diseases, particularly in hypertrichosis and distinctive coarse facial features.
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Affiliation(s)
- Fengji Cui
- Department of Molecular Genetics, Chifeng Maternity Hospital, Chifeng, China
| | - Tuoya Wulan
- Department of Reproduction, Chifeng Maternity Hospital, Chifeng, China
| | | | | | - Yuhua Jiang
- Department of Obstetrics, Chifeng Maternity Hospital, Chifeng, China
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4
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Hou T, Chen L. Sulfonylurea receptor 2 (SUR2), intricate sensors for intracellular Mg-nucleotides. Bioessays 2024; 46:e2300151. [PMID: 38227376 DOI: 10.1002/bies.202300151] [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: 08/16/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/17/2024]
Abstract
SUR2, similar to SUR1, is a regulatory subunit of the ATP-sensitive potassium channel (KATP), which plays a key role in numerous important physiological processes and is implicated in various diseases. Recent structural studies have revealed that, like SUR1, SUR2 can undergo ligand-dependent dynamic conformational changes, transitioning between an inhibitory inward-facing conformation and an activating occluded conformation. In addition, SUR2 possesses a unique inhibitory Regulatory helix (R helix) that is absent in SUR1. The binding of the activating Mg-ADP to NBD2 of SUR2 competes with the inhibitory Mg-ATP, thereby promoting the release of the R helix and initiating the activation process. Moreover, the signal generated by Mg-ADP binding to NBD2 might be directly transmitted to the TMD of SUR2, prior to NBD dimerization. Furthermore, the C-terminal 42 residues (C42) of SUR2 might allosterically regulate the kinetics of Mg-nucleotide binding on NBD2. These distinctive properties render SUR2 intricate sensors for intracellular Mg-nucleotides.
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Affiliation(s)
- Tianyi Hou
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China
- National Biomedical Imaging Center, Peking University, Beijing, Beijing, China
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Li K, McClenahan SJ, Han C, Bungard JD, Rathnayake U, Boutaud O, Bauer JA, Days EL, Lindsley CW, Shelton EL, Denton JS. Discovery and Characterization of VU0542270, the First Selective Inhibitor of Vascular Kir6.1/SUR2B K ATP Channels. Mol Pharmacol 2024; 105:202-212. [PMID: 38302135 PMCID: PMC10877733 DOI: 10.1124/molpharm.123.000783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/21/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024] Open
Abstract
Vascular smooth muscle KATP channels critically regulate blood flow and blood pressure by modulating vascular tone and therefore represent attractive drug targets for treating several cardiovascular disorders. However, the lack of potent inhibitors that can selectively inhibit Kir6.1/SUR2B (vascular KATP) over Kir6.2/SUR1 (pancreatic KATP) has eluded discovery despite decades of intensive research. We therefore screened 47,872 chemically diverse compounds for novel inhibitors of heterologously expressed Kir6.1/SUR2B channels. The most potent inhibitor identified in the screen was an N-aryl-N'-benzyl urea compound termed VU0542270. VU0542270 inhibits Kir6.1/SUR2B with an IC50 of approximately 100 nM but has no apparent activity toward Kir6.2/SUR1 or several other members of the Kir channel family at doses up to 30 µM (>300-fold selectivity). By expressing different combinations of Kir6.1 or Kir6.2 with SUR1, SUR2A, or SUR2B, the VU0542270 binding site was localized to SUR2. Initial structure-activity relationship exploration around VU0542270 revealed basic texture related to structural elements that are required for Kir6.1/SUR2B inhibition. Analysis of the pharmacokinetic properties of VU0542270 showed that it has a short in vivo half-life due to extensive metabolism. In pressure myography experiments on isolated mouse ductus arteriosus vessels, VU0542270 induced ductus arteriosus constriction in a dose-dependent manner similar to that of the nonspecific KATP channel inhibitor glibenclamide. The discovery of VU0542270 provides conceptual proof that SUR2-specific KATP channel inhibitors can be developed using a molecular target-based approach and offers hope for developing cardiovascular therapeutics targeting Kir6.1/SUR2B. SIGNIFICANCE STATEMENT: Small-molecule inhibitors of vascular smooth muscle KATP channels might represent novel therapeutics for patent ductus arteriosus, migraine headache, and sepsis; however, the lack of selective channel inhibitors has slowed progress in these therapeutic areas. Here, this study describes the discovery and characterization of the first vascular-specific KATP channel inhibitor, VU0542270.
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Affiliation(s)
- Kangjun Li
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Samantha J McClenahan
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Changho Han
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Joseph D Bungard
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Upendra Rathnayake
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Olivier Boutaud
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Joshua A Bauer
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Emily L Days
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Craig W Lindsley
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Elaine L Shelton
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Jerod S Denton
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
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6
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Yang Y, Chen L. Functional dissection of KATP channel structures reveals the importance of a conserved interface. Structure 2024; 32:168-176.e2. [PMID: 38101402 DOI: 10.1016/j.str.2023.11.008] [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: 08/03/2023] [Revised: 10/24/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023]
Abstract
ATP-sensitive potassium channels (KATP) are inhibited by ATP but activated by Mg-ADP, coupling the intracellular ATP/ADP ratio to the potassium conductance of the plasma membrane. Although there has been progress in determining the structure of KATP, the functional significance of the domain-domain interface in the gating properties of KATP channels remains incompletely understood. In this study, we define the structure of KATP as two modules: KATPcore and SURABC. Based on this model, we identified two functionally important interfaces between these two modules, namely interface I and interface II. Further structure-guided mutagenesis experiments indicate that destabilizing interface II by deleting ECL3 on the SUR1 subunit impairs KNtp-independent Mg-ADP activation, demonstrating the essential role of intramolecular interactions between KATPcore and SURABC in Mg-ADP activation. Additionally, interface II is functionally conserved between SUR1 and SUR2, and the hydrophobic residue F351 on ECL3 of SUR1 is crucial for maintaining the stability of this interface.
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Affiliation(s)
- Yaxiong Yang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; National Biomedical Imaging Center, Peking University, Beijing 100871, China.
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ElSheikh A, Driggers CM, Shyng SL. Non-radioactive Rb + Efflux Assay for Screening K ATP Channel Modulators. Methods Mol Biol 2024; 2796:191-210. [PMID: 38856903 DOI: 10.1007/978-1-0716-3818-7_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
ATP-sensitive potassium (KATP) channels function as metabolic sensors that link cell membrane excitability to the cellular energy status by controlling potassium ion (K+) flow across the cell membrane according to intracellular ATP and ADP concentrations. As such, KATP channels influence a broad spectrum of physiological processes, including insulin secretion and cardiovascular functions. KATP channels are hetero-octamers, consisting of four inward rectifier potassium channel subunits, Kir6.1 or Kir6.2, and four sulfonylurea receptors (SURs), SUR1, SUR2A, or SUR2B. Different Kir6 and SUR isoforms assemble into KATP channel subtypes with distinct tissue distributions and physiological functions. Mutations in the genes encoding KATP channel subunits underlie various human diseases. Targeted treatment for these diseases requires subtype-specific KATP channel modulators. Rubidium ions (Rb+) also pass through KATP channels, and Rb+ efflux assays can be used to assess KATP channel function and activity. Flame atomic absorption spectroscopy (Flame-AAS) combined with microsampling can measure Rb+ in small volume, which provides an efficient tool to screen for compounds that alter KATP channel activity in Rb+ efflux assays. In this chapter, we describe a detailed protocol for Rb+ efflux assays designed to identify new KATP channel modulators with potential therapeutic utilities.
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Affiliation(s)
- Assmaa ElSheikh
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA.
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt.
| | - Camden M Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
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Montani D, Antigny F, Jutant EM, Chaumais MC, Le Ribeuz H, Grynblat J, Khouri C, Humbert M. Pulmonary hypertension associated with diazoxide: the SUR1 paradox. ERJ Open Res 2023; 9:00350-2023. [PMID: 37965230 PMCID: PMC10641583 DOI: 10.1183/23120541.00350-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 09/04/2023] [Indexed: 11/16/2023] Open
Abstract
The ATP-sensitive potassium channels and their regulatory subunits, sulfonylurea receptor 1 (SUR1/Kir6.2) and SUR2/Kir6.1, contribute to the pathophysiology of pulmonary hypertension (PH). Loss-of-function pathogenic variants in the ABCC8 gene, which encodes for SUR1, have been associated with heritable pulmonary arterial hypertension. Conversely, activation of SUR1 and SUR2 leads to the relaxation of pulmonary arteries and reduces cell proliferation and migration. Diazoxide, a SUR1 activator, has been shown to alleviate experimental PH, suggesting its potential as a therapeutic option. However, there are paradoxical reports of diazoxide-induced PH in infants. This review explores the role of SUR1/2 in the pathophysiology of PH and the contradictory effects of diazoxide on the pulmonary vascular bed. Additionally, we conducted a comprehensive literature review of cases of diazoxide-associated PH and analysed data from the World Health Organization pharmacovigilance database (VigiBase). Significant disproportionality signals link diazoxide to PH, while no other SUR activators have been connected with pulmonary vascular disease. Diazoxide-associated PH seems to be dose-dependent and potentially related to acute effects on the pulmonary vascular bed. Further research is required to decipher the differing pulmonary vascular consequences of diazoxide in different age populations and experimental models.
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Affiliation(s)
- David Montani
- Université Paris-Saclay, Faculty of Medicine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Department of Respiratory and Intensive Care Medicine, Pulmonary Hypertension National Referral Centre, Hôpital Bicêtre, DMU 5 Thorinno, Le Kremlin-Bicêtre, France
| | - Fabrice Antigny
- Université Paris-Saclay, Faculty of Medicine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
| | - Etienne-Marie Jutant
- CHU de Poitiers, Respiratory Department, INSERM CIC 1402, IS-ALIVE Research Group, University of Poitiers, Poitiers, France
| | - Marie-Camille Chaumais
- INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Department of Pharmacy, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
- Université Paris-Saclay, Faculty of Pharmacy, Saclay, France
| | - Hélène Le Ribeuz
- Université Paris-Saclay, Faculty of Medicine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
| | - Julien Grynblat
- Université Paris-Saclay, Faculty of Medicine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
| | - Charles Khouri
- Univ. Grenoble Alpes, HP2 Laboratory, Grenoble, France
- Grenoble Alpes University Hospital, Pharmacovigilance Unit, Grenoble, France
| | - Marc Humbert
- Université Paris-Saclay, Faculty of Medicine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999, Hôpital Marie Lannelongue, Le Plessis Robinson, France
- Assistance Publique-Hôpitaux de Paris (AP-HP), Department of Respiratory and Intensive Care Medicine, Pulmonary Hypertension National Referral Centre, Hôpital Bicêtre, DMU 5 Thorinno, Le Kremlin-Bicêtre, France
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Nijboer TCW, Hessel EVS, van Haaften GW, van Zandvoort MJ, van der Spek PJ, Troelstra C, de Kovel CGF, Koeleman BPC, van der Zwaag B, Brilstra EH, Burbach JPH. Identification of candidate genes for developmental colour agnosia in a single unique family. PLoS One 2023; 18:e0290013. [PMID: 37672513 PMCID: PMC10482254 DOI: 10.1371/journal.pone.0290013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 07/31/2023] [Indexed: 09/08/2023] Open
Abstract
Colour agnosia is a disorder that impairs colour knowledge (naming, recognition) despite intact colour perception. Previously, we have identified the first and only-known family with hereditary developmental colour agnosia. The aim of the current study was to explore genomic regions and candidate genes that potentially cause this trait in this family. For three family members with developmental colour agnosia and three unaffected family members CGH-array analysis and exome sequencing was performed, and linkage analysis was carried out using DominantMapper, resulting in the identification of 19 cosegregating chromosomal regions. Whole exome sequencing resulted in 11 rare coding variants present in all affected family members with developmental colour agnosia and absent in unaffected members. These variants affected genes that have been implicated in neural processes and functions (CACNA2D4, DDX25, GRINA, MYO15A) or that have an indirect link to brain function, development or disease (MAML2, STAU1, TMED3, RABEPK), and a remaining group lacking brain expression or involved in non-neural traits (DEPDC7, OR1J1, OR8D4). Although this is an explorative study, the small set of candidate genes that could serve as a starting point for unravelling mechanisms of higher level cognitive functions and cortical specialization, and disorders therein such as developmental colour agnosia.
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Affiliation(s)
- Tanja C. W. Nijboer
- UMCU Brain Center and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, The Netherlands
- Department of Experimental Psychology and Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
| | - Ellen V. S. Hessel
- UMCU Brain Center and Center of Excellence for Rehabilitation Medicine, University Medical Center Utrecht and De Hoogstraat Rehabilitation, Utrecht, The Netherlands
- Department of Biomedical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Gijs W. van Haaften
- Department of Biomedical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martine J. van Zandvoort
- Department of Experimental Psychology and Helmholtz Institute, Utrecht University, Utrecht, The Netherlands
| | - Peter J. van der Spek
- Department of Pathology, Erasmus Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Christine Troelstra
- Department of Pathology, Erasmus Medical Center Rotterdam, Rotterdam, the Netherlands
| | - Carolien G. F. de Kovel
- Department of Biomedical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bobby P. C. Koeleman
- Department of Biomedical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Bert van der Zwaag
- Department of Biomedical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Eva H. Brilstra
- Department of Biomedical Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - J. Peter H. Burbach
- UMCU Brain Center, Department of Translational Neuroscience, University Medical Center Utrecht, Utrecht, the Netherlands
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Gao J, McClenaghan C, Matreyek KA, Grange DK, Nichols CG. Rapid Characterization of the Functional and Pharmacological Consequences of Cantú Syndrome K ATP Channel Mutations in Intact Cells. J Pharmacol Exp Ther 2023; 386:298-309. [PMID: 37527933 PMCID: PMC10449099 DOI: 10.1124/jpet.123.001659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/10/2023] [Accepted: 06/01/2023] [Indexed: 08/03/2023] Open
Abstract
Gain-of-function of KATP channels, resulting from mutations in either KCNJ8 (encoding inward rectifier sub-family 6 [Kir6.1]) or ABCC9 (encoding sulphonylurea receptor [SUR2]), cause Cantú syndrome (CS), a channelopathy characterized by excess hair growth, coarse facial appearance, cardiomegaly, and lymphedema. Here, we established a pipeline for rapid analysis of CS mutation consequences in Landing pad HEK 293 cell lines stably expressing wild type (WT) and mutant human Kir6.1 and SUR2B. Thallium-influx and cell membrane potential, reported by fluorescent Tl-sensitive Fluozin-2 and voltage-sensitive bis-(1,3-dibutylbarbituric acid)trimethine oxonol (DiBAC4(3)) dyes, respectively, were used to assess channel activity. In the Tl-influx assay, CS-associated Kir6.1 mutations increased sensitivity to the ATP-sensitive potassium (KATP) channel activator, pinacidil, but there was strikingly little effect of pinacidil for any SUR2B mutations, reflecting unexpected differences in the molecular mechanisms of Kir6.1 versus SUR2B mutations. Compared with the Tl-influx assay, the DiBAC4(3) assay presents more significant signal changes in response to subtle KATP channel activity changes, and all CS mutants (both Kir6.1 and SUR2B), but not WT channels, caused marked hyperpolarization, demonstrating that all mutants were activated under ambient conditions in intact cells. Most SUR2 CS mutations were markedly inhibited by <100 nM glibenclamide, but sensitivity to inhibition by glibenclamide, repaglinide, and PNU37883A was markedly reduced for Kir6.1 CS mutations. Understanding functional consequences of mutations can help with disease diagnosis and treatment. The analysis pipeline we have developed has the potential to rapidly identify mutational consequences, aiding future CS diagnosis, drug discovery, and individualization of treatment. SIGNIFICANCE STATEMENT: We have developed new fluorescence-based assays of channel activities and drug sensitivities of Cantú syndrome (CS) mutations in human Kir6.1/SUR2B-dependent KATP channels, showing that Kir6.1 mutations increase sensitivity to potassium channel openers, while SUR2B mutations markedly reduce K channel opener (KCO) sensitivity. However, both Kir6.1 and SUR2B CS mutations are both more hyperpolarized than WT cells under basal conditions, confirming pathophysiologically relevant gain-of-function, validating DiBAC4(3) fluorescence to characterize hyperpolarization induced by KATP channel activity under basal, non KCO-activated conditions.
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Affiliation(s)
- Jian Gao
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Conor McClenaghan
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Kenneth A Matreyek
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Dorothy K Grange
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Colin G Nichols
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
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11
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Hanson A, McClenaghan C, Weng KC, Colijn S, Stratman AN, Halabi CM, Grange DK, Silva JR, Nichols CG. Electrophysiology of human iPSC-derived vascular smooth muscle cells and cell autonomous consequences of Cantu Syndrome mutations. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.29.547088. [PMID: 37425756 PMCID: PMC10327170 DOI: 10.1101/2023.06.29.547088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Objective Cantu Syndrome (CS), a multisystem disease with a complex cardiovascular phenotype, is caused by GoF variants in the Kir6.1/SUR2 subunits of ATP-sensitive potassium (K ATP ) channels, and is characterized by low systemic vascular resistance, as well as tortuous, dilated vessels, and decreased pulse-wave velocity. Thus, CS vascular dysfunction is multifactorial, with distinct hypomyotonic and hyperelastic components. To dissect whether such complexities arise cell-autonomously within vascular smooth muscle cells (VSMCs), or as secondary responses to the pathophysiological milieu, we assessed electrical properties and gene expression in human induced pluripotent stem cell-derived VSMCs (hiPSC-VSMCs), differentiated from control and CS patient-derived hiPSCs, and in native mouse control and CS VSMCs. Approach and Results Whole-cell voltage-clamp of isolated aortic and mesenteric VSMCs isolated from wild type (WT) and Kir6.1[V65M] (CS) mice revealed no difference in voltage-gated K + (K v ) or Ca 2+ currents. K v and Ca 2+ currents were also not different between validated hiPSC-VSMCs differentiated from control and CS patient-derived hiPSCs. Pinacidil-sensitive K ATP currents in control hiPSC-VSMCs were consistent with those in WT mouse VSMCs, and were considerably larger in CS hiPSC-VSMCs. Consistent with lack of any compensatory modulation of other currents, this resulted in membrane hyperpolarization, explaining the hypomyotonic basis of CS vasculopathy. Increased compliance and dilation in isolated CS mouse aortae, was associated with increased elastin mRNA expression. This was consistent with higher levels of elastin mRNA in CS hiPSC-VSMCs, suggesting that the hyperelastic component of CS vasculopathy is a cell-autonomous consequence of vascular K ATP GoF. Conclusions The results show that hiPSC-VSMCs reiterate expression of the same major ion currents as primary VSMCs, validating the use of these cells to study vascular disease. The results further indicate that both the hypomyotonic and hyperelastic components of CS vasculopathy are cell-autonomous phenomena driven by K ATP overactivity within VSMCs.
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12
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Ding D, Hou T, Wei M, Wu JX, Chen L. The inhibition mechanism of the SUR2A-containing K ATP channel by a regulatory helix. Nat Commun 2023; 14:3608. [PMID: 37330603 PMCID: PMC10276813 DOI: 10.1038/s41467-023-39379-4] [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: 07/11/2022] [Accepted: 06/10/2023] [Indexed: 06/19/2023] Open
Abstract
KATP channels are metabolic sensors for intracellular ATP/ADP ratios, play essential roles in many physiological processes, and are implicated in a spectrum of pathological conditions. SUR2A-containing KATP channels differ from other subtypes in their sensitivity to Mg-ADP activation. However, the underlying structural mechanism remains poorly understood. Here we present a series of cryo-EM structures of SUR2A in the presence of different combinations of Mg-nucleotides and the allosteric inhibitor repaglinide. These structures uncover regulatory helix (R helix) on the NBD1-TMD2 linker, which wedges between NBD1 and NBD2. R helix stabilizes SUR2A in the NBD-separated conformation to inhibit channel activation. The competitive binding of Mg-ADP with Mg-ATP to NBD2 mobilizes the R helix to relieve such inhibition, allowing channel activation. The structures of SUR2B in similar conditions suggest that the C-terminal 42 residues of SUR2B enhance the structural dynamics of NBD2 and facilitate the dissociation of the R helix and the binding of Mg-ADP to NBD2, promoting NBD dimerization and subsequent channel activation.
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Affiliation(s)
- Dian Ding
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Tianyi Hou
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Miao Wei
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Jing-Xiang Wu
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China.
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China.
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13
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Gisladottir RS, Helgason A, Halldorsson BV, Helgason H, Borsky M, Chien YR, Gudnason J, Gudjonsson SA, Moisik S, Dediu D, Thorleifsson G, Tragante V, Bustamante M, Jonsdottir GA, Stefansdottir L, Rutsdottir G, Magnusson SH, Hardarson M, Ferkingstad E, Halldorsson GH, Rognvaldsson S, Skuladottir A, Ivarsdottir EV, Norddahl G, Thorgeirsson G, Jonsdottir I, Ulfarsson MO, Holm H, Stefansson H, Thorsteinsdottir U, Gudbjartsson DF, Sulem P, Stefansson K. Sequence variants affecting voice pitch in humans. SCIENCE ADVANCES 2023; 9:eabq2969. [PMID: 37294764 PMCID: PMC10256171 DOI: 10.1126/sciadv.abq2969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/04/2023] [Indexed: 06/11/2023]
Abstract
The genetic basis of the human vocal system is largely unknown, as are the sequence variants that give rise to individual differences in voice and speech. Here, we couple data on diversity in the sequence of the genome with voice and vowel acoustics in speech recordings from 12,901 Icelanders. We show how voice pitch and vowel acoustics vary across the life span and correlate with anthropometric, physiological, and cognitive traits. We found that voice pitch and vowel acoustics have a heritable component and discovered correlated common variants in ABCC9 that associate with voice pitch. The ABCC9 variants also associate with adrenal gene expression and cardiovascular traits. By showing that voice and vowel acoustics are influenced by genetics, we have taken important steps toward understanding the genetics and evolution of the human vocal system.
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Affiliation(s)
- Rosa S. Gisladottir
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Department of Icelandic and Comparative Cultural Studies, University of Iceland, Saemundargata 2, 102 Reykjavik, Iceland
| | - Agnar Helgason
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Department of Anthropology, University of Iceland, Saemundargata 10, 102 Reykjavik, Iceland
| | - Bjarni V. Halldorsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | - Hannes Helgason
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | - Michal Borsky
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | - Yu-Ren Chien
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | - Jon Gudnason
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | | | - Scott Moisik
- Division of Linguistics and Multilingual Studies, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Dan Dediu
- Department of Catalan Philology and General Linguistics, University of Barcelona, Gran Via 585, Barcelona 08007, Spain
- University of Barcelona Institute for Complex Systems (UBICS), Martí Franquès 1, Barcelona 08028, Spain
- Catalan Institute for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, Barcelona 08010, Spain
| | | | | | | | | | | | | | | | | | - Egil Ferkingstad
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | - Gisli H. Halldorsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland
| | | | | | | | | | - Gudmundur Thorgeirsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
| | - Ingileif Jonsdottir
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
| | - Magnus O. Ulfarsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland
| | - Hilma Holm
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | | | - Unnur Thorsteinsdottir
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
| | - Daniel F. Gudbjartsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland
| | - Patrick Sulem
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | - Kari Stefansson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
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14
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McClenaghan C, Mukadam MA, Roeglin J, Tryon RC, Grabner M, Dayal A, Meyer GA, Nichols CG. Skeletal muscle delimited myopathy and verapamil toxicity in SUR2 mutant mouse models of AIMS. EMBO Mol Med 2023; 15:e16883. [PMID: 37154692 PMCID: PMC10245035 DOI: 10.15252/emmm.202216883] [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: 09/14/2022] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 05/10/2023] Open
Abstract
ABCC9-related intellectual disability and myopathy syndrome (AIMS) arises from loss-of-function (LoF) mutations in the ABCC9 gene, which encodes the SUR2 subunit of ATP-sensitive potassium (KATP ) channels. KATP channels are found throughout the cardiovascular system and skeletal muscle and couple cellular metabolism to excitability. AIMS individuals show fatigability, muscle spasms, and cardiac dysfunction. We found reduced exercise performance in mouse models of AIMS harboring premature stop codons in ABCC9. Given the roles of KATP channels in all muscles, we sought to determine how myopathy arises using tissue-selective suppression of KATP and found that LoF in skeletal muscle, specifically, underlies myopathy. In isolated muscle, SUR2 LoF results in abnormal generation of unstimulated forces, potentially explaining painful spasms in AIMS. We sought to determine whether excessive Ca2+ influx through CaV 1.1 channels was responsible for myopathology but found that the Ca2+ channel blocker verapamil unexpectedly resulted in premature death of AIMS mice and that rendering CaV 1.1 channels nonpermeable by mutation failed to reverse pathology; results which caution against the use of calcium channel blockers in AIMS.
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Affiliation(s)
- Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
- Center for Advanced Biotechnology and Medicine, and Departments of Pharmacology and Medicine, Robert Wood Johnson Medical SchoolRutgers UniversityPiscatawayNJUSA
| | - Maya A Mukadam
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Jacob Roeglin
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Robert C Tryon
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Manfred Grabner
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Anamika Dayal
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Gretchen A Meyer
- Program in Physical Therapy, Departments of Orthopaedic Surgery, Neurology and Biomedical EngineeringWashington University School of MedicineSt. LouisMOUSA
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
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15
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Abstract
ABC transporters are essential for cellular physiology. Humans have 48 ABC genes organized into seven distinct families. Of these genes, 44 (in five distinct families) encode for membrane transporters, of which several are involved in drug resistance and disease pathways resulting from transporter dysfunction. Over the last decade, advances in structural biology have vastly expanded our mechanistic understanding of human ABC transporter function, revealing details of their molecular arrangement, regulation, and interactions, facilitated in large part by advances in cryo-EM that have rendered hitherto inaccessible targets amenable to high-resolution structural analysis. As a result, experimentally determined structures of multiple members of each of the five families of ABC transporters in humans are now available. Here we review this recent progress, highlighting the physiological relevance of human ABC transporters and mechanistic insights gleaned from their direct structure determination. We also discuss the impact and limitations of model systems and structure prediction methods in understanding human ABC transporters and discuss current challenges and future research directions.
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Affiliation(s)
- Amer Alam
- The Hormel Institute, University of Minnesota, Austin, Minnesota, USA
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, ETH Zurich, Switzerland;
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16
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Furrow E, Tate N, Minor K, Martinson S, Larrabee S, Anttila M, Sleeper M, Henthorn P. An ABCC9 Missense Variant Is Associated with Sudden Cardiac Death and Dilated Cardiomyopathy in Juvenile Dogs. Genes (Basel) 2023; 14:genes14050988. [PMID: 37239348 DOI: 10.3390/genes14050988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/23/2023] [Accepted: 04/26/2023] [Indexed: 05/28/2023] Open
Abstract
Sudden cardiac death in the young (SCDY) is a devastating event that often has an underlying genetic basis. Manchester Terrier dogs offer a naturally occurring model of SCDY, with sudden death of puppies as the manifestation of an inherited dilated cardiomyopathy (DCM). We performed a genome-wide association study for SCDY/DCM in Manchester Terrier dogs and identified a susceptibility locus harboring the cardiac ATP-sensitive potassium channel gene ABCC9. Sanger sequencing revealed an ABCC9 p.R1186Q variant present in a homozygous state in all SCDY/DCM-affected dogs (n = 26). None of the controls genotyped (n = 398) were homozygous for the variant, but 69 were heterozygous carriers, consistent with autosomal recessive inheritance with complete penetrance (p = 4 × 10-42 for the association of homozygosity for ABCC9 p.R1186Q with SCDY/DCM). This variant exists at low frequency in human populations (rs776973456) with clinical significance previously deemed uncertain. The results of this study further the evidence that ABCC9 is a susceptibility gene for SCDY/DCM and highlight the potential application of dog models to predict the clinical significance of human variants.
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Affiliation(s)
- Eva Furrow
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55455, USA
| | - Nicole Tate
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55455, USA
| | - Katie Minor
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55455, USA
| | - Shannon Martinson
- Atlantic Veterinary College, University of Prince Edward Island, Charlottetown, PE CIA 4P3, Canada
| | - Shannon Larrabee
- College of Veterinary Medicine, University of Minnesota, St. Paul, MN 55455, USA
| | | | - Meg Sleeper
- College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Paula Henthorn
- School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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17
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Davis MJ, Castorena-Gonzalez JA, Kim HJ, Li M, Remedi M, Nichols CG. Lymphatic contractile dysfunction in mouse models of Cantú Syndrome with K ATP channel gain-of-function. FUNCTION 2023; 4:zqad017. [PMID: 37214333 PMCID: PMC10194823 DOI: 10.1093/function/zqad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 04/01/2023] [Accepted: 04/07/2023] [Indexed: 05/24/2023] Open
Abstract
Cantú Syndrome (CS) is an autosomal dominant disorder caused by gain-of-function (GoF) mutations in the Kir6.1 and SUR2 subunits of KATP channels. KATP overactivity results in a chronic reduction in arterial tone and hypotension, leading to other systemic cardiovascular complications. However, the underlying mechanism of lymphedema, developed by >50% of CS patients, is unknown. We investigated whether lymphatic contractile dysfunction occurs in mice expressing CS mutations in Kir6.1 (Kir6.1[V65M]) or SUR2 (SUR2[A478V], SUR2[R1154Q]). Pressure myograph tests of contractile function of popliteal lymphatic vessels over the physiological pressure range revealed significantly impaired contractile strength and reduced frequency of spontaneous contractions at all pressures in heterozygous Kir6.1[V65M] vessels, compared to control littermates. Contractile dysfunction of intact popliteal lymphatics in vivo was confirmed using near-infrared fluorescence microscopy. Homozygous SUR2[A478V] vessels exhibited profound contractile dysfunction ex vivo, but heterozygous SUR2[A478V] vessels showed essentially normal contractile function. However, further investigation of vessels from all three GoF mouse strains revealed significant disruption in contraction wave entrainment, decreased conduction speed and distance, multiple pacemaker sites, and reversing wave direction. Tests of 2-valve lymphatic vessels forced to pump against an adverse pressure gradient revealed that all CS-associated genotypes were essentially incapable of pumping under an imposed outflow load. Our results show that varying degrees of lymphatic contractile dysfunction occur in proportion to the degree of molecular GoF in Kir6.1 or SUR2. This is the first example of lymphatic contractile dysfunction caused by a smooth muscle ion channel mutation and potentially explains the susceptibility of CS patients to lymphedema.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia MO 65212, USA
| | | | - Hae Jin Kim
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia MO 65212, USA
| | - Min Li
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia MO 65212, USA
| | - Maria Remedi
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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18
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Yan Z, Zhong L, Zhu W, Chung SK, Hou P. Chinese herbal medicine for the treatment of cardiovascular diseases ─ targeting cardiac ion channels. Pharmacol Res 2023; 192:106765. [PMID: 37075871 DOI: 10.1016/j.phrs.2023.106765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/04/2023] [Accepted: 04/12/2023] [Indexed: 04/21/2023]
Abstract
Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality, imposing an increasing global health burden. Cardiac ion channels (voltage-gated NaV, CaV, KVs, and others) synergistically shape the cardiac action potential (AP) and control the heartbeat. Dysfunction of these channels, due to genetic mutations, transcriptional or post-translational modifications, may disturb the AP and lead to arrhythmia, a major risk for CVD patients. Although there are five classes of anti-arrhythmic drugs available, they can have varying levels of efficacies and side effects on patients, possibly due to the complex pathogenesis of arrhythmias. As an alternative treatment option, Chinese herbal remedies have shown promise in regulating cardiac ion channels and providing anti-arrhythmic effects. In this review, we first discuss the role of cardiac ion channels in maintaining normal heart function and the pathogenesis of CVD, then summarize the classification of Chinese herbal compounds, and elaborate detailed mechanisms of their efficacy in regulating cardiac ion channels and in alleviating arrhythmia and CVD. We also address current limitations and opportunities for developing new anti-CVD drugs based on Chinese herbal medicines.
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Affiliation(s)
- Zhenzhen Yan
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Ling Zhong
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China
| | - Wandi Zhu
- Cardiovascular Medicine Division and Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
| | - Sookja Kim Chung
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China; Faculty of Medicine & Faculty of Innovation Engineering at Macau University of Science and Technology, Taipa, Macao SAR, China; State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong, China
| | - Panpan Hou
- Dr. Neher's Biophysics Laboratory for Innovative Drug Discovery, State Key Laboratory of Quality Research in Chinese Medicine, Macau University of Science and Technology, Taipa, Macao SAR, China; Macau University of Science and Technology Zhuhai MUST Science and Technology Research Institute. Zhuhai, Guangdong, China.
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19
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Scala R, Maqoud F, McClenaghan C, Harter TM, Perrone MG, Scilimati A, Nichols CG, Tricarico D. Zoledronic Acid Blocks Overactive Kir6.1/SUR2-Dependent K ATP Channels in Skeletal Muscle and Osteoblasts in a Murine Model of Cantú Syndrome. Cells 2023; 12:928. [PMID: 36980269 PMCID: PMC10047381 DOI: 10.3390/cells12060928] [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: 12/21/2022] [Revised: 02/24/2023] [Accepted: 03/11/2023] [Indexed: 03/22/2023] Open
Abstract
Cantú syndrome (CS) is caused by the gain of function mutations in the ABCC9 and KCNJ8 genes encoding, respectively, for the sulfonylureas receptor type 2 (SUR2) and the inwardly rectifier potassium channel 6.1 (Kir6.1) of the ATP-sensitive potassium (KATP) channels. CS is a multi-organ condition with a cardiovascular phenotype, neuromuscular symptoms, and skeletal malformations. Glibenclamide has been proposed for use in CS, but even in animals, the drug is incompletely effective against severe mutations, including the Kir6.1wt/V65M. Patch-clamp experiments showed that zoledronic acid (ZOL) fully reduced the whole-cell KATP currents in bone calvaria cells from wild type (WT/WT) and heterozygous Kir6.1wt/V65MCS mice, with IC50 for ZOL block < 1 nM in each case. ZOL fully reduced KATP current in excised patches in skeletal muscle fibers in WT/WT and CS mice, with IC50 of 100 nM in each case. Interestingly, KATP currents in the bone of heterozygous SUR2wt/A478V mice were less sensitive to ZOL inhibition, showing an IC50 of ~500 nM and a slope of ~0.3. In homozygous SUR2A478V/A478V cells, ZOL failed to fully inhibit the KATP currents, causing only ~35% inhibition at 100 μM, but was responsive to glibenclamide. ZOL reduced the KATP currents in Kir6.1wt/VMCS mice in both skeletal muscle and bone cells but was not effective in the SUR2[A478V] mice fibers. These data indicate a subunit specificity of ZOL action that is important for appropriate CS therapies.
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Affiliation(s)
- Rosa Scala
- Sections of Pharmacology, Medicinal Chemistry, Department of Pharmacy—Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy
| | - Fatima Maqoud
- Sections of Pharmacology, Medicinal Chemistry, Department of Pharmacy—Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy
| | - Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA
| | - Theresa M. Harter
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA
| | - Maria Grazia Perrone
- Sections of Pharmacology, Medicinal Chemistry, Department of Pharmacy—Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy
| | - Antonio Scilimati
- Sections of Pharmacology, Medicinal Chemistry, Department of Pharmacy—Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy
| | - Colin G. Nichols
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA
| | - Domenico Tricarico
- Sections of Pharmacology, Medicinal Chemistry, Department of Pharmacy—Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy
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20
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Oepen K, Mater V, Schneider D. Unfolding Individual Domains of BmrA, a Bacterial ABC Transporter Involved in Multidrug Resistance. Int J Mol Sci 2023; 24:ijms24065239. [PMID: 36982314 PMCID: PMC10049088 DOI: 10.3390/ijms24065239] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/01/2023] [Accepted: 03/06/2023] [Indexed: 03/30/2023] Open
Abstract
The folding and stability of proteins are often studied via unfolding (and refolding) a protein with urea. Yet, in the case of membrane integral protein domains, which are shielded by a membrane or a membrane mimetic, urea generally does not induce unfolding. However, the unfolding of α-helical membrane proteins may be induced by the addition of sodium dodecyl sulfate (SDS). When protein unfolding is followed via monitoring changes in Trp fluorescence characteristics, the contributions of individual Trp residues often cannot be disentangled, and, consequently, the folding and stability of the individual domains of a multi-domain membrane protein cannot be studied. In this study, the unfolding of the homodimeric bacterial ATP-binding cassette (ABC) transporter Bacillus multidrug resistance ATP (BmrA), which comprises a transmembrane domain and a cytosolic nucleotide-binding domain, was investigated. To study the stability of individual BmrA domains in the context of the full-length protein, the individual domains were silenced by mutating the existent Trps. The SDS-induced unfolding of the corresponding constructs was compared to the (un)folding characteristics of the wild-type (wt) protein and isolated domains. The full-length variants BmrAW413Y and BmrAW104YW164A were able to mirror the changes observed with the isolated domains; thus, these variants allowed for the study of the unfolding and thermodynamic stability of mutated domains in the context of full-length BmrA.
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Affiliation(s)
- Kristin Oepen
- Department of Chemistry-Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Veronika Mater
- Department of Chemistry-Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
| | - Dirk Schneider
- Department of Chemistry-Biochemistry, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
- Institute of Molecular Physiology, Johannes Gutenberg University Mainz, Hanns-Dieter-Hüsch-Weg 17, 55128 Mainz, Germany
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21
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Preclinical Ultrasonography in Rodent Models of Neuromuscular Disorders: The State of the Art for Diagnostic and Therapeutic Applications. Int J Mol Sci 2023; 24:ijms24054976. [PMID: 36902405 PMCID: PMC10003358 DOI: 10.3390/ijms24054976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 03/01/2023] [Accepted: 03/02/2023] [Indexed: 03/08/2023] Open
Abstract
Ultrasonography is a safe, non-invasive imaging technique used in several fields of medicine, offering the possibility to longitudinally monitor disease progression and treatment efficacy over time. This is particularly useful when a close follow-up is required, or in patients with pacemakers (not suitable for magnetic resonance imaging). By virtue of these advantages, ultrasonography is commonly used to detect multiple skeletal muscle structural and functional parameters in sports medicine, as well as in neuromuscular disorders, e.g., myotonic dystrophy and Duchenne muscular dystrophy (DMD). The recent development of high-resolution ultrasound devices allowed the use of this technique in preclinical settings, particularly for echocardiographic assessments that make use of specific guidelines, currently lacking for skeletal muscle measurements. In this review, we describe the state of the art for ultrasound skeletal muscle applications in preclinical studies conducted in small rodents, aiming to provide the scientific community with necessary information to support an independent validation of these procedures for the achievement of standard protocols and reference values useful in translational research on neuromuscular disorders.
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22
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Gao J, McClenaghan C, Christiaans I, Alders M, van Duinen K, van Haelst MM, van Haaften G, Nichols CG. Lymphedema as first clinical presentation of Cantu Syndrome: reversed phenotyping after identification of gain-of-function variant in ABCC9. Eur J Hum Genet 2023; 31:188-194. [PMID: 36336713 PMCID: PMC9905590 DOI: 10.1038/s41431-022-01210-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/16/2022] [Accepted: 09/30/2022] [Indexed: 11/09/2022] Open
Abstract
Cantu Syndrome (CS), [OMIM #239850] is characterized by hypertrichosis, osteochondrodysplasia, and cardiomegaly. CS is caused by gain-of-function (GOF) variants in the KCNJ8 or ABCC9 genes that encode pore-forming Kir6.1 and regulatory SUR2 subunits of ATP-sensitive potassium (KATP) channels. Many subjects with CS also present with the complication of lymphedema. A previously uncharacterized, heterozygous ABCC9 variant, p.(Leu1055_Glu1058delinsPro), termed indel1055, was identified in an individual diagnosed with idiopathic lymphedema. The variant was introduced into the equivalent position of rat SUR2A, and inside-out patches were used to characterize the KATP channels formed by Kir6.2 and WT or mutant SUR2A subunits coexpressed in Cosm6 cells. The indel1055 variant causes gain-of-function of the channel, with an increase of the IC50 for ATP inhibition compared to WT. Retrospective consideration of this individual reveals clear features of Cantu Syndrome. An additional heterozygous ABCC9 variant, p.(Ile419Thr), was identified in a second individual diagnosed with lymphedema. In this case, there were no additional features consistent with CS, and the properties of p.(Ile416Thr) (the corresponding mutation in rat SUR2A)--containing channels were not different from WT. This proof-of-principle study shows that idiopathic lymphedema may actually be a first presentation of otherwise unrecognized Cantu Syndrome, but molecular phenotyping of identified variants is necessary to confirm relevance.
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Affiliation(s)
- Jian Gao
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis, St. Louis, MO, USA
| | - Conor McClenaghan
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis, St. Louis, MO, USA
| | - Imke Christiaans
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Marielle Alders
- University of Amsterdam, Department of Human Genetics, Meibergdreef 9, Amsterdam, The Netherlands
| | - Kirsten van Duinen
- Department of Dermatology, Nij Smellinghe Hospital, Drachten, The Netherlands
| | - Mieke M van Haelst
- University of Amsterdam, Department of Human Genetics, Meibergdreef 9, Amsterdam, The Netherlands.
- Departments of Pediatrics, Amsterdam University Medical Centers, Amsterdam, The Netherlands.
- Emma Center for Personalized Medicine, Amsterdam University Medical Centers, Amsterdam, The Netherlands.
| | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Colin G Nichols
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis, St. Louis, MO, USA.
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23
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Nichols CG. Personalized Therapeutics for K ATP-Dependent Pathologies. Annu Rev Pharmacol Toxicol 2023; 63:541-563. [PMID: 36170658 PMCID: PMC9868118 DOI: 10.1146/annurev-pharmtox-051921-123023] [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: 01/26/2023]
Abstract
Ubiquitously expressed throughout the body, ATP-sensitive potassium (KATP) channels couple cellular metabolism to electrical activity in multiple tissues; their unique assembly as four Kir6 pore-forming subunits and four sulfonylurea receptor (SUR) subunits has resulted in a large armory of selective channel opener and inhibitor drugs. The spectrum of monogenic pathologies that result from gain- or loss-of-function mutations in these channels, and the potential for therapeutic correction of these pathologies, is now clear. However, while available drugs can be effective treatments for specific pathologies, cross-reactivity with the other Kir6 or SUR subfamily members can result in drug-induced versions of each pathology and may limit therapeutic usefulness. This review discusses the background to KATP channel physiology, pathology, and pharmacology and considers the potential for more specific or effective therapeutic agents.
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Affiliation(s)
- Colin G. Nichols
- Center for the Investigation of Membrane Excitability Diseases and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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24
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Le Ribeuz H, Masson B, Dutheil M, Boët A, Beauvais A, Sabourin J, De Montpreville VT, Capuano V, Mercier O, Humbert M, Montani D, Antigny F. Involvement of SUR2/Kir6.1 channel in the physiopathology of pulmonary arterial hypertension. Front Cardiovasc Med 2023; 9:1066047. [PMID: 36704469 PMCID: PMC9871631 DOI: 10.3389/fcvm.2022.1066047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 12/20/2022] [Indexed: 01/12/2023] Open
Abstract
Aims We hypothesized that the ATP-sensitive K+ channels (KATP) regulatory subunit (ABCC9) contributes to PAH pathogenesis. ABCC9 gene encodes for two regulatory subunits of KATP channels: the SUR2A and SUR2B proteins. In the KATP channel, the SUR2 subunits are associated with the K+ channel Kir6.1. We investigated how the SUR2/Kir6.1 channel contributes to PAH pathogenesis and its potential as a therapeutic target in PAH. Methods and results Using in vitro, ex vivo, and in vivo approaches, we analyzed the localization and expression of SUR2A, SUR2B, and Kir6.1 in the pulmonary vasculature of controls and patients with PAH as in experimental pulmonary hypertension (PH) rat models and its contribution to PAH physiopathology. Finally, we deciphered the consequences of in vivo activation of SUR2/Kir6.1 in the monocrotaline (MCT)-induced PH model. We found that SUR2A, SUR2B, and Kir6.1 were expressed in the lungs of controls and patients with PAH and MCT-induced PH rat models. Organ bath studies showed that SUR2 activation by pinacidil induced relaxation of pulmonary arterial in rats and humans. In vitro experiments on human pulmonary arterial smooth muscle cells and endothelial cells (hPASMCs and hPAECs) in controls and PAH patients showed decreased cell proliferation and migration after SUR2 activation. We demonstrated that SUR2 activation in rat right ventricular (RV) cardiomyocytes reduced RV action potential duration by patch-clamp. Chronic pinacidil administration in control rats increased heart rate without changes in hemodynamic parameters. Finally, in vivo pharmacological activation of SUR2 on MCT and Chronic-hypoxia (CH)-induced-PH rats showed improved PH. Conclusion We showed that SUR2A, SUR2B, and Kir6.1 are presented in hPASMCs and hPAECs of controls and PAH patients. In vivo SUR2 activation reduced the MCT-induced and CH-induced PH phenotype, suggesting that SUR2 activation should be considered for treating PAH.
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Affiliation(s)
- Hélène Le Ribeuz
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Bastien Masson
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Mary Dutheil
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France,Hôptal Marie Lannelongue, Groupe Hospitalier Paris Saint-Joseph, Le Plessis Robinson, France
| | - Angèle Boët
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Antoine Beauvais
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France
| | - Jessica Sabourin
- Inserm, UMR-S 1180, Signalisation et Physiopathologie Cardiovasculaire, Université Paris-Saclay, Orsay, France
| | | | - Véronique Capuano
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France,Hôptal Marie Lannelongue, Groupe Hospitalier Paris Saint-Joseph, Le Plessis Robinson, France
| | - Olaf Mercier
- Service de Chirurgie Thoracique, Vasculaire et Transplantation Cardio-Pulmonaire, Hôpital Marie Lannelongue, Groupe Hospitalier Paris Saint Joseph, Le Plessis Robinson, France
| | - Marc Humbert
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France,Assistance Publique–Hôpitaux de Paris (AP-HP), Service de Pneumologie et Soins Intensifs Respiratoires, Centre de Référence de l’Hypertension Pulmonaire, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - David Montani
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France,Assistance Publique–Hôpitaux de Paris (AP-HP), Service de Pneumologie et Soins Intensifs Respiratoires, Centre de Référence de l’Hypertension Pulmonaire, Hôpital Bicêtre, Le Kremlin-Bicêtre, France
| | - Fabrice Antigny
- Université Paris-Saclay, Faculté de Médecine, Le Kremlin-Bicêtre, France,INSERM UMR_S 999 « Hypertension Pulmonaire Physiopathologie et Innovation Thérapeutique », Hôpital Marie Lannelongue, Le Plessis-Robinson, France,*Correspondence: Fabrice Antigny,
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25
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Singh GK, McClenaghan C, Aggarwal M, Gu H, Remedi MS, Grange DK, Nichols CG. A Unique High-Output Cardiac Hypertrophy Phenotype Arising From Low Systemic Vascular Resistance in Cantu Syndrome. J Am Heart Assoc 2022; 11:e027363. [PMID: 36515236 PMCID: PMC9798820 DOI: 10.1161/jaha.122.027363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Accepted: 10/25/2022] [Indexed: 12/15/2022]
Abstract
Background Cardiomegaly caused by left ventricular hypertrophy is a risk factor for development of congestive heart failure, classically associated with decreased systolic and/or diastolic ventricular function. Less attention has been given to the phenotype of left ventricular hypertrophy with enhanced ventricular function and increased cardiac output, which is potentially associated with high-output heart failure. Lack of recognition may pose diagnostic ambiguity and management complexities. Methods and Results We sought to systematically characterize high-output cardiac hypertrophy in subjects with Cantu syndrome (CS), caused by gain-of-function variants in ABCC9, which encodes cardiovascular KATP (ATP-sensitive potassium) channel subunits. We studied the cardiovascular phenotype longitudinally in 31 subjects with CS with confirmed ABCC9 variants (median [interquartile range] age 8 years [3-32 years], body mass index 19.9 [16.5-22.9], 16 male subjects). Subjects with CS presented with significant left ventricular hypertrophy (left ventricular mass index 86.7 [57.7-103.0] g/m2 in CS, n=30; 26.6 [24.1-32.8] g/m2 in controls, n=17; P<0.0001) and low blood pressure (systolic 94.5 [90-103] mm Hg in CS, n=17; 109 [98-115] mm Hg in controls, n=17; P=0.0301; diastolic 60 [56-66] mm Hg in CS, n=17; 69 [65-72] mm Hg in control, n=17; P=0.0063). Most (21/31) subjects with CS exhibited eccentric hypertrophy with normal left ventricular wall thickness. Congestive heart failure symptoms were evident in 4 of the 5 subjects with CS aged >40 years on long-term follow-up. Conclusions The data define the natural history of high-output cardiac hypertrophy resulting from decreased systemic vascular resistance in subjects with CS, a defining population for long-term consequences of high-output hypertrophy caused by low systemic vascular resistance, and the potential for progression to high-output heart failure.
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Affiliation(s)
- Gautam K. Singh
- Division of Cardiology, Department of PediatricsWashington University School of MedicineSt. LouisMO
- Center for the Investigation of Membrane Excitability Diseases (CIMED)Washington University School of MedicineSt. LouisMO
| | - Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases (CIMED)Washington University School of MedicineSt. LouisMO
- Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMO
| | - Manish Aggarwal
- Division of Cardiology, Department of PediatricsWashington University School of MedicineSt. LouisMO
| | - Hongjie Gu
- Division of StatisticsWashington University School of MedicineSt. LouisMO
| | - Maria S. Remedi
- Center for the Investigation of Membrane Excitability Diseases (CIMED)Washington University School of MedicineSt. LouisMO
- Department of Medicine, Division of EndocrinologyWashington University School of MedicineSt. LouisMO
| | - Dorothy K. Grange
- Center for the Investigation of Membrane Excitability Diseases (CIMED)Washington University School of MedicineSt. LouisMO
- Department of Pediatrics, Division of GeneticsWashington University School of MedicineSt. LouisMO
| | - Colin G. Nichols
- Center for the Investigation of Membrane Excitability Diseases (CIMED)Washington University School of MedicineSt. LouisMO
- Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMO
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26
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Crespo-García T, Rubio-Alarcón M, Cámara-Checa A, Dago M, Rapún J, Nieto-Marín P, Marín M, Cebrián J, Tamargo J, Delpón E, Caballero R. A Cantú syndrome mutation produces dual effects on KATP channels by disrupting ankyrin B regulation. J Gen Physiol 2022; 155:213613. [PMID: 36287534 PMCID: PMC9614705 DOI: 10.1085/jgp.202112995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 09/09/2022] [Accepted: 10/04/2022] [Indexed: 02/01/2023] Open
Abstract
ATP-sensitive potassium (KATP) channels composed of Kir6.x and sulfonylurea receptor (SURs) subunits couple cellular metabolism to electrical activity. Cantú syndrome (CS) is a rare disease caused by mutations in the genes encoding Kir6.1 (KCNJ8) and SUR2A (ABCC9) that produce KATP channel hyperactivity due to a reduced channel block by physiological ATP concentrations. We functionally characterized the p.S1054Y SUR2A mutation identified in two CS carriers, who exhibited a mild phenotype although the mutation was predicted as highly pathogenic. We recorded macroscopic and single-channel currents in CHO and HEK-293 cells and measured the membrane expression of the channel subunits by biotinylation assays in HEK-293 cells. The mutation increased basal whole-cell current density and at the single-channel level, it augmented opening frequency, slope conductance, and open probability (Po), and promoted the appearance of multiple conductance levels. p.S1054Y also reduced Kir6.2 and SUR2A expression specifically at the membrane. Overexpression of ankyrin B (AnkB) prevented these gain- and loss-of-function effects, as well as the p.S1054Y-induced reduction of ATP inhibition of currents measured in inside-out macropatches. Yeast two-hybrid assays suggested that SUR2A WT and AnkB interact, while p.S1054Y interaction with AnkB is decreased. The p.E322K Kir6.2 mutation, which prevents AnkB binding to Kir6.2, produced similar biophysical alterations than p.S1054Y. Our results are the first demonstration of a CS mutation whose functional consequences involve the disruption of AnkB effects on KATP channels providing a novel mechanism by which CS mutations can reduce ATP block. Furthermore, they may help explain the mild phenotype associated with this mutation.
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Affiliation(s)
- Teresa Crespo-García
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Marcos Rubio-Alarcón
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Anabel Cámara-Checa
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - María Dago
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Josu Rapún
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Paloma Nieto-Marín
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - María Marín
- Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Jorge Cebrián
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Juan Tamargo
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
| | - Eva Delpón
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain,Correspondence to Eva Delpón:
| | - Ricardo Caballero
- Department of Pharmacology and Toxicology, School of Medicine, Universidad Complutense de Madrid, Instituto de Investigación Gregorio Marañón, Madrid, Spain,Centro de Investigación Biomédica en Red Enfermedades Cardiovasculares, Madrid, Spain
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27
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Davis MJ, Kim HJ, Nichols CG. K ATP channels in lymphatic function. Am J Physiol Cell Physiol 2022; 323:C1018-C1035. [PMID: 35785984 PMCID: PMC9550566 DOI: 10.1152/ajpcell.00137.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 06/22/2022] [Accepted: 06/23/2022] [Indexed: 11/22/2022]
Abstract
KATP channels function as negative regulators of active lymphatic pumping and lymph transport. This review summarizes and critiques the evidence for the expression of specific KATP channel subunits in lymphatic smooth muscle and endothelium, the roles that they play in normal lymphatic function, and their possible involvement in multiple diseases, including metabolic syndrome, lymphedema, and Cantú syndrome. For each of these topics, suggestions are made for directions for future research.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri
| | - Hae Jin Kim
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, Missouri
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
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McClenaghan C, Nichols CG. Kir6.1 and SUR2B in Cantú syndrome. Am J Physiol Cell Physiol 2022; 323:C920-C935. [PMID: 35876283 PMCID: PMC9467476 DOI: 10.1152/ajpcell.00154.2022] [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: 04/14/2022] [Revised: 07/07/2022] [Accepted: 07/07/2022] [Indexed: 12/25/2022]
Abstract
Kir6.1 and SUR2 are subunits of ATP-sensitive potassium (KATP) channels expressed in a wide range of tissues. Extensive study has implicated roles of these channel subunits in diverse physiological functions. Together they generate the predominant KATP conductance in vascular smooth muscle and are the target of vasodilatory drugs. Roles for Kir6.1/SUR2 dysfunction in disease have been suggested based on studies of animal models and human genetic discoveries. In recent years, it has become clear that gain-of-function (GoF) mutations in both genes result in Cantú syndrome (CS)-a complex, multisystem disorder. There is currently no targeted therapy for CS, but studies of mouse models of the disease reveal that pharmacological reversibility of cardiovascular and gastrointestinal pathologies can be achieved by administration of the KATP channel inhibitor, glibenclamide. Here we review the function, structure, and physiological and pathological roles of Kir6.1/SUR2B channels, with a focus on CS. Recent studies have led to much improved understanding of the underlying pathologies and the potential for treatment, but important questions remain: Can the study of genetically defined CS reveal new insights into Kir6.1/SUR2 function? Do these reveal new pathophysiological mechanisms that may be important in more common diseases? And is our pharmacological armory adequately stocked?
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Affiliation(s)
- Conor McClenaghan
- Department of Cell Biology and Physiology, Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St. Louis, Missouri
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St. Louis, Missouri
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Structural insights into the mechanism of pancreatic K ATP channel regulation by nucleotides. Nat Commun 2022; 13:2770. [PMID: 35589716 PMCID: PMC9120461 DOI: 10.1038/s41467-022-30430-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 04/28/2022] [Indexed: 11/17/2022] Open
Abstract
ATP-sensitive potassium channels (KATP) are metabolic sensors that convert the intracellular ATP/ADP ratio to the excitability of cells. They are involved in many physiological processes and implicated in several human diseases. Here we present the cryo-EM structures of the pancreatic KATP channel in both the closed state and the pre-open state, resolved in the same sample. We observe the binding of nucleotides at the inhibitory sites of the Kir6.2 channel in the closed but not in the pre-open state. Structural comparisons reveal the mechanism for ATP inhibition and Mg-ADP activation, two fundamental properties of KATP channels. Moreover, the structures also uncover the activation mechanism of diazoxide-type KATP openers. KATP channels are energy sensors. Here, authors report the Cryo-EM structures of pancreatic KATP in both the closed state and the pre-open state. These structures illuminate the mechanism of KATP channel regulation by the intracellular nucleotides.
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30
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Marques P, Korbonits M. Approach to the Patient With Pseudoacromegaly. J Clin Endocrinol Metab 2022; 107:1767-1788. [PMID: 34792134 DOI: 10.1210/clinem/dgab789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Indexed: 11/19/2022]
Abstract
Pseudoacromegaly encompasses a heterogeneous group of conditions in which patients have clinical features of acromegaly or gigantism, but no excess of GH or IGF-1. Acromegaloid physical features or accelerated growth in a patient may prompt referral to endocrinologists. Because pseudoacromegaly conditions are rare and heterogeneous, often with overlapping clinical features, the underlying diagnosis may be challenging to establish. As many of these have a genetic origin, such as pachydermoperiostosis, Sotos syndrome, Weaver syndrome, or Cantú syndrome, collaboration is key with clinical geneticists in the diagnosis of these patients. Although rare, awareness of these uncommon conditions and their characteristic features will help their timely recognition.
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Affiliation(s)
- Pedro Marques
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, EC1M 6BQ London, UK
- Endocrinology Department, Hospital de Santa Maria, Centro Hospitalar Universitário de Lisboa Norte, Lisboa, Portugal
| | - Márta Korbonits
- Centre for Endocrinology, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, EC1M 6BQ London, UK
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31
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Ding D, Wu JX, Duan X, Ma S, Lai L, Chen L. Structural identification of vasodilator binding sites on the SUR2 subunit. Nat Commun 2022; 13:2675. [PMID: 35562524 PMCID: PMC9106677 DOI: 10.1038/s41467-022-30428-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 04/28/2022] [Indexed: 11/09/2022] Open
Abstract
ATP-sensitive potassium channels (KATP), composed of Kir6 and SUR subunits, convert the metabolic status of the cell into electrical signals. Pharmacological activation of SUR2- containing KATP channels by class of small molecule drugs known as KATP openers leads to hyperpolarization of excitable cells and to vasodilation. Thus, KATP openers could be used to treat cardiovascular diseases. However, where these vasodilators bind to KATP and how they activate the channel remains elusive. Here, we present cryo-EM structures of SUR2A and SUR2B subunits in complex with Mg-nucleotides and P1075 or levcromakalim, two chemically distinct KATP openers that are specific to SUR2. Both P1075 and levcromakalim bind to a common site in the transmembrane domain (TMD) of the SUR2 subunit, which is between TMD1 and TMD2 and is embraced by TM10, TM11, TM12, TM14, and TM17. These KATP openers synergize with Mg-nucleotides to stabilize SUR2 in the NBD-dimerized occluded state to activate the channel.
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Affiliation(s)
- Dian Ding
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China.,Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China.,Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China.,National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Jing-Xiang Wu
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China.,National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Xinli Duan
- Beijing Jingtai Technology Co., Ltd., Beijing, China
| | - Songling Ma
- Beijing Jingtai Technology Co., Ltd., Beijing, China
| | - Lipeng Lai
- Beijing Jingtai Technology Co., Ltd., Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China. .,Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China. .,Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China. .,National Biomedical Imaging Center, Peking University, 100871, Beijing, China.
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32
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Ando K, Tong L, Peng D, Vázquez-Liébanas E, Chiyoda H, He L, Liu J, Kawakami K, Mochizuki N, Fukuhara S, Grutzendler J, Betsholtz C. KCNJ8/ABCC9-containing K-ATP channel modulates brain vascular smooth muscle development and neurovascular coupling. Dev Cell 2022; 57:1383-1399.e7. [PMID: 35588738 DOI: 10.1016/j.devcel.2022.04.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Revised: 12/22/2021] [Accepted: 04/26/2022] [Indexed: 12/30/2022]
Abstract
Loss- or gain-of-function mutations in ATP-sensitive potassium channel (K-ATP)-encoding genes, KCNJ8 and ABCC9, cause human central nervous system disorders with unknown pathogenesis. Here, using mice, zebrafish, and cell culture models, we investigated cellular and molecular causes of brain dysfunctions derived from altered K-ATP channel function. We show that genetic/chemical inhibition or activation of KCNJ8/ABCC9-containing K-ATP channel function leads to brain-selective suppression or promotion of arterial/arteriolar vascular smooth muscle cell (VSMC) differentiation, respectively. We further show that brain VSMCs develop from KCNJ8/ABCC9-containing K-ATP channel-expressing mural cell progenitor and that K-ATP channel cell autonomously regulates VSMC differentiation through modulation of intracellular Ca2+ oscillation via voltage-dependent calcium channels. Consistent with defective VSMC development, Kcnj8 knockout mice showed deficiency in vasoconstrictive capacity and neuronal-evoked vasodilation leading to local hyperemia. Our results demonstrate a role for KCNJ8/ABCC9-containing K-ATP channels in the differentiation of brain VSMC, which in turn is necessary for fine-tuning of cerebral blood flow.
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Affiliation(s)
- Koji Ando
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Dag Hammarskjölds väg 20, 751 85 Uppsala, Sweden; Department of Molecular Pathophysiology, Institute of Advanced Medical Science, Nippon Medical School, 1-1-5 Sendagi Bunkyo-ku, Tokyo 113-8602, Japan; Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe-Shinmachi, Suita, Osaka 564-8565, Japan.
| | - Lei Tong
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | - Di Peng
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Dag Hammarskjölds väg 20, 751 85 Uppsala, Sweden
| | - Elisa Vázquez-Liébanas
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Dag Hammarskjölds väg 20, 751 85 Uppsala, Sweden
| | - Hirohisa Chiyoda
- Department of Molecular Pathophysiology, Institute of Advanced Medical Science, Nippon Medical School, 1-1-5 Sendagi Bunkyo-ku, Tokyo 113-8602, Japan; Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe-Shinmachi, Suita, Osaka 564-8565, Japan
| | - Liqun He
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Dag Hammarskjölds väg 20, 751 85 Uppsala, Sweden
| | - Jianping Liu
- Department of Medicine Huddinge (MedH), Karolinska Institute, Campus Flemingsburg, Neo, Blickagången 16, 141 57 Huddinge, Sweden
| | - Koichi Kawakami
- Laboratory of Molecular and Developmental Biology, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka 411-8540, Japan; Department of Genetics, SOKENDAI (The Graduate University for Advanced Studies), 1111 Yata, Mishima, Shizuoka 411-8540, Japan
| | - Naoki Mochizuki
- Department of Cell Biology, National Cerebral and Cardiovascular Center Research Institute, 6-1 Kishibe-Shinmachi, Suita, Osaka 564-8565, Japan
| | - Shigetomo Fukuhara
- Department of Molecular Pathophysiology, Institute of Advanced Medical Science, Nippon Medical School, 1-1-5 Sendagi Bunkyo-ku, Tokyo 113-8602, Japan
| | - Jaime Grutzendler
- Department of Neurology, Yale School of Medicine, New Haven, CT, USA
| | - Christer Betsholtz
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Dag Hammarskjölds väg 20, 751 85 Uppsala, Sweden; Department of Medicine Huddinge (MedH), Karolinska Institute, Campus Flemingsburg, Neo, Blickagången 16, 141 57 Huddinge, Sweden.
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33
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Scala R, Maqoud F, Antonacci M, Dibenedetto JR, Perrone MG, Scilimati A, Castillo K, Latorre R, Conte D, Bendahhou S, Tricarico D. Bisphosphonates Targeting Ion Channels and Musculoskeletal Effects. Front Pharmacol 2022; 13:837534. [PMID: 35370739 PMCID: PMC8965324 DOI: 10.3389/fphar.2022.837534] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 02/25/2022] [Indexed: 12/25/2022] Open
Abstract
Bisphosphonates (BPs) are the most used bone-specific anti-resorptive agents, often chosen as first-line therapy in several bone diseases characterized by an imbalance between osteoblast-mediated bone production and osteoclast-mediated bone resorption. BPs target the farnesyl pyrophosphate synthase (FPPS) in osteoclasts, reducing bone resorption. Lately, there has been an increasing interest in BPs direct pro-survival/pro-mineralizing properties in osteoblasts and their pain-relieving effects. Even so, molecular targets involved in these effects appear now largely elusive. Ion channels are emerging players in bone homeostasis. Nevertheless, the effects of BPs on these proteins have been poorly described. Here we reviewed the actions of BPs on ion channels in musculoskeletal cells. In particular, the TRPV1 channel is essential for osteoblastogenesis. Since it is involved in bone pain sensation, TRPV1 is a possible alternative target of BPs. Ion channels are emerging targets and anti-target for bisphosphonates. Zoledronic acid can be the first selective musculoskeletal and vascular KATP channel blocker targeting with high affinity the inward rectifier channels Kir6.1-SUR2B and Kir6.2-SUR2A. The action of this drug against the overactive mutants of KCNJ9-ABCC9 genes observed in the Cantu’ Syndrome (CS) may improve the appropriate prescription in those CS patients affected by musculoskeletal disorders such as bone fracture and bone frailty.
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Affiliation(s)
- Rosa Scala
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Bari, Italy
| | - Fatima Maqoud
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Bari, Italy
| | - Marina Antonacci
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Bari, Italy
| | | | - Maria Grazia Perrone
- Medicinal Chemistry Section, Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Bari, Italy
| | - Antonio Scilimati
- Medicinal Chemistry Section, Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Bari, Italy
| | - Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile.,Centro de Investigación de Estudios Avanzados, Universidad Católica del Maule, Talca, Chile
| | - Ramón Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Diana Conte
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Bari, Italy
| | - Saïd Bendahhou
- UMR7370 CNRS, Laboratoire de Physiomédecine Moléculaire (LP2M), Labex ICST, Nice, France
| | - Domenico Tricarico
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari, Bari, Italy
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34
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Welch CL, Chung WK. Channelopathy Genes in Pulmonary Arterial Hypertension. Biomolecules 2022; 12:biom12020265. [PMID: 35204766 PMCID: PMC8961593 DOI: 10.3390/biom12020265] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 01/22/2022] [Accepted: 01/25/2022] [Indexed: 02/07/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is a rare, progressive vasculopathy with significant cardiopulmonary morbidity and mortality. The underlying pathogenetic mechanisms are heterogeneous and current therapies aim to decrease pulmonary vascular resistance but no curative treatments are available. Causal genetic variants can be identified in ~13% of adults and 43% of children with PAH. Knowledge of genetic diagnoses can inform clinical management of PAH, including multimodal medical treatment, surgical intervention and transplantation decisions, and screening for associated conditions, as well as risk stratification for family members. Roles for rare variants in three channelopathy genes—ABCC8, ATP13A3, and KCNK3—have been validated in multiple PAH cohorts, and in aggregate explain ~2.7% of PAH cases. Complete or partial loss of function has been demonstrated for PAH-associated variants in ABCC8 and KCNK3. Channels can be excellent targets for drugs, and knowledge of mechanisms for channel mutations may provide an opportunity for the development of PAH biomarkers and novel therapeutics for patients with hereditary PAH but also potentially more broadly for all patients with PAH.
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Affiliation(s)
- Carrie L. Welch
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY 10032, USA;
| | - Wendy K. Chung
- Department of Pediatrics, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Medicine, Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
- Correspondence:
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35
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Houtman MJC, Friesacher T, Chen X, Zangerl-Plessl EM, van der Heyden MAG, Stary-Weinzinger A. Development of I KATP Ion Channel Blockers Targeting Sulfonylurea Resistant Mutant K IR6.2 Based Channels for Treating DEND Syndrome. Front Pharmacol 2022; 12:814066. [PMID: 35095528 PMCID: PMC8795863 DOI: 10.3389/fphar.2021.814066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: DEND syndrome is a rare channelopathy characterized by a combination of developmental delay, epilepsy and severe neonatal diabetes. Gain of function mutations in the KCNJ11 gene, encoding the KIR6.2 subunit of the IKATP potassium channel, stand at the basis of most forms of DEND syndrome. In a previous search for existing drugs with the potential of targeting Cantú Syndrome, also resulting from increased IKATP, we found a set of candidate drugs that may also possess the potential to target DEND syndrome. In the current work, we combined Molecular Modelling including Molecular Dynamics simulations, with single cell patch clamp electrophysiology, in order to test the effect of selected drug candidates on the KIR6.2 WT and DEND mutant channels. Methods: Molecular dynamics simulations were performed to investigate potential drug binding sites. To conduct in vitro studies, KIR6.2 Q52R and L164P mutants were constructed. Inside/out patch clamp electrophysiology on transiently transfected HEK293T cells was performed for establishing drug-channel inhibition relationships. Results: Molecular Dynamics simulations provided insight in potential channel interaction and shed light on possible mechanisms of action of the tested drug candidates. Effective IKIR6.2/SUR2a inhibition was obtained with the pore-blocker betaxolol (IC50 values 27-37 μM). Levobetaxolol effectively inhibited WT and L164P (IC50 values 22 μM) and Q52R (IC50 55 μM) channels. Of the SUR binding prostaglandin series, travoprost was found to be the best blocker of WT and L164P channels (IC50 2-3 μM), while Q52R inhibition was 15-20% at 10 μM. Conclusion: Our combination of MD and inside-out electrophysiology provides the rationale for drug mediated IKATP inhibition, and will be the basis for 1) screening of additional existing drugs for repurposing to address DEND syndrome, and 2) rationalized medicinal chemistry to improve IKATP inhibitor efficacy and specificity.
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Affiliation(s)
- Marien J C Houtman
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Theres Friesacher
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Xingyu Chen
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Eva-Maria Zangerl-Plessl
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Anna Stary-Weinzinger
- Department of Pharmaceutical Sciences, Division of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
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Mäkitie RE, Toiviainen-Salo S, Kaitila I, Mäkitie O. A Novel Osteochondrodysplasia With Empty Sella Associates With a TBX2 Variant. Front Endocrinol (Lausanne) 2022; 13:845889. [PMID: 35311234 PMCID: PMC8927981 DOI: 10.3389/fendo.2022.845889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Skeletal dysplasias comprise a heterogenous group of developmental disorders of skeletal and cartilaginous tissues. Several different forms have been described and the full spectrum of their clinical manifestations and underlying genetic causes are still incompletely understood. We report a three-generation Finnish family with an unusual, autosomal dominant form of osteochondrodysplasia and an empty sella. Affected individuals (age range 24-44 years) exhibit unusual codfish-shaped vertebrae, severe early-onset and debilitating osteoarthritis and an empty sella without endocrine abnormalities. Clinical characteristics also include mild dysmorphic features, reduced sitting height ratio, and obesity. Whole-exome sequencing excluded known skeletal dysplasias and identified a novel heterozygous missense mutation c.899C>T (p.Thr300Met) in TBX2, confirmed by Sanger sequencing. TBX2 is important for development of the skeleton and the brain and three prior reports have described variations in TBX2 in patients portraying a complex phenotype with vertebral anomalies, craniofacial dysmorphism and endocrine dysfunctions. Our mutation lies near a previously reported disease-causing variant and is predicted pathogenic with deleterious effects on protein function. Our findings expand the current spectrum of skeletal dysplasias, support the association of TBX2 mutations with skeletal dysplasia and suggest a role for TBX2 in development of the spinal and craniofacial structures and the pituitary gland.
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Affiliation(s)
- Riikka E. Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology–Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- *Correspondence: Riikka E. Mäkitie,
| | - Sanna Toiviainen-Salo
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Medical Imaging Center, Pediatric Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ilkka Kaitila
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Department of Clinical Genetics, Helsinki University Hospital, Helsinki, Finland
| | - Outi Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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37
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Aka TD, Saha U, Shati SA, Aziz MA, Begum M, Hussain MS, Millat MS, Uddin MS, Islam MS. Risk of type 2 diabetes mellitus and cardiovascular complications in KCNJ11, HHEX and SLC30A8 genetic polymorphisms carriers: A case-control study. Heliyon 2021; 7:e08376. [PMID: 34849419 PMCID: PMC8608605 DOI: 10.1016/j.heliyon.2021.e08376] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/15/2021] [Accepted: 11/10/2021] [Indexed: 01/10/2023] Open
Abstract
Background Type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD) are two deadly diseases caused by the complex interaction of multiple genetic loci, lifestyle and environmental factors. Genome-wide association studies described hundreds of susceptibility loci for T2DM and T2DM-related CVD, but it remains uncertain due to geographic and ethnic variations. The objective of this study was to evaluate the associations of KCNJ11 rs5219, SLC30A8 rs13266634 and HHEX rs1111875 polymorphisms with T2DM and related CVD. Methods Genotyping of all three polymorphisms was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method on 250 T2DM cases and 246 healthy controls. Both descriptive and inferential statistical methods were applied using MedCalc and IBM SPSS software programs for statistical analyses. Results A significantly increased association of KCNJ11 rs5219 (p<0.05) with T2DM was found in dominant, recessive, heterozygote, homozygote, and allele model (aOR = 2.23, 2.03, 1.90, 3.09, and 1.80, respectively). For SLC30A8 rs13266634, only dominant, heterozygote, and allele model (aOR = 3.37, 3.59, and 1.79, respectively) showed significantly increased association with T2DM. SNP rs1111875 (HHEX) also revealed 2.08, 4.18, 5.93, and 2.08-times significant association in dominant, recessive, homozygote, and allele models. Besides, a significantly reduced correlation of KCNJ11 rs5219 was found with T2DM-related CVD in the recessive and allele model (aOR = 0.40 and 0.65, respectively). Again, a significant difference was observed between T2DM-related CVD and non-CVD patients in terms of gender distribution, fasting blood glucose (FBG), systolic blood pressure (SBP), diastolic blood pressure (DBP), total cholesterol (TC), and triglycerides (TG). Conclusions Our investigation indicates that KCNJ11 rs5219, SLC30A8 rs13266634 and HHEX rs1111875 polymorphisms are associated with T2DM. Moreover, KCNJ11 rs5219 polymorphism is correlated with the risk of T2DM-related CVD.
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Affiliation(s)
- Tutun Das Aka
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Urmi Saha
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Sayara Akter Shati
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Md Abdul Aziz
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh.,Laboratory of Pharmacogenomics and Molecular Biology, Department of Pharmacy, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Mobashera Begum
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Md Saddam Hussain
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Md Shalahuddin Millat
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh.,Laboratory of Pharmacogenomics and Molecular Biology, Department of Pharmacy, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Mohammad Sarowar Uddin
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh.,Laboratory of Pharmacogenomics and Molecular Biology, Department of Pharmacy, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
| | - Mohammad Safiqul Islam
- Department of Pharmacy, Faculty of Science, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh.,Laboratory of Pharmacogenomics and Molecular Biology, Department of Pharmacy, Noakhali Science and Technology University, Sonapur, 3814, Noakhali, Bangladesh
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Singareddy SS, Roessler HI, McClenaghan C, Ikle JM, Tryon RC, van Haaften G, Nichols CG. ATP-sensitive potassium channels in zebrafish cardiac and vascular smooth muscle. J Physiol 2021; 600:299-312. [PMID: 34820842 DOI: 10.1113/jp282157] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 11/18/2021] [Indexed: 12/12/2022] Open
Abstract
ATP-sensitive potassium channels (KATP channels) are hetero-octameric nucleotide-gated ion channels that couple cellular metabolism to excitability in various tissues. In the heart, KATP channels are activated during ischaemia and potentially during adrenergic stimulation. In the vasculature, they are normally active at a low level, reducing vascular tone, but the ubiquitous nature of these channels leads to complex and poorly understood channelopathies as a result of gain- or loss-of-function mutations. Zebrafish (ZF) models of these channelopathies may provide insights to the link between molecular dysfunction and complex pathophysiology, but this requires understanding the tissue dependence of channel activity and subunit specificity. Thus far, direct analysis of ZF KATP expression and functional properties has only been performed in pancreatic β-cells. Using a comprehensive combination of genetically modified fish, electrophysiology and gene expression analysis, we demonstrate that ZF cardiac myocytes (CM) and vascular smooth muscle (VSM) express functional KATP channels of similar subunit composition, structure and metabolic sensitivity to their mammalian counterparts. However, in contrast to mammalian cardiovascular KATP channels, ZF channels are insensitive to potassium channel opener drugs (pinacidil, minoxidil) in both chambers of the heart and in VSM. The results provide a first characterization of the molecular properties of fish KATP channels and validate the use of such genetically modified fish as models of human Cantú syndrome and ABCC9-related Intellectual Disability and Myopathy syndrome. KEY POINTS: Zebrafish cardiac myocytes (CM) and vascular smooth muscle (VSM) express functional KATP channels of similar subunit composition, structure and metabolic sensitivity to their mammalian counterparts. In contrast to mammalian cardiovascular KATP channels, zebrafish channels are insensitive to potassium channel opener drugs (pinacidil, minoxidil) in both chambers of the heart and in VSM. We provide a first characterization of the molecular properties of fish KATP channels and validate the use of such genetically modified fish as models of human Cantú syndrome and ABCC9-related Intellectual Disability and Myopathy syndrome.
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Affiliation(s)
- Soma S Singareddy
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, MO, USA
| | - Helen I Roessler
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Conor McClenaghan
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, MO, USA
| | - Jennifer M Ikle
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, MO, USA
| | - Robert C Tryon
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, MO, USA
| | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Colin G Nichols
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St Louis, St Louis, MO, USA
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Vascular K ATP channel structural dynamics reveal regulatory mechanism by Mg-nucleotides. Proc Natl Acad Sci U S A 2021; 118:2109441118. [PMID: 34711681 PMCID: PMC8694068 DOI: 10.1073/pnas.2109441118] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/30/2021] [Indexed: 11/24/2022] Open
Abstract
Vascular KATP channels formed by the potassium channel Kir6.1 and its regulatory protein SUR2B maintain blood pressure in the physiological range. Overactivity of the channel due to genetic mutations in either Kir6.1 or SUR2B causes severe cardiovascular pathologies known as Cantú syndrome. The cryogenic electron microscopy structures of the vascular KATP channel reported here show multiple, dynamically related conformations of the regulatory subunit SUR2B. Molecular dynamics simulations reveal the negatively charged ED-domain in SUR2B, a stretch of 15 glutamate (E) and aspartate (D) residues not previously resolved, play a key MgADP-dependent role in mediating interactions at the interface between the SUR2B and Kir6.1 subunits. Our findings provide a mechanistic understanding of how channel activity is regulated by intracellular MgADP. Vascular tone is dependent on smooth muscle KATP channels comprising pore-forming Kir6.1 and regulatory SUR2B subunits, in which mutations cause Cantú syndrome. Unique among KATP isoforms, they lack spontaneous activity and require Mg-nucleotides for activation. Structural mechanisms underlying these properties are unknown. Here, we determined cryogenic electron microscopy structures of vascular KATP channels bound to inhibitory ATP and glibenclamide, which differ informatively from similarly determined pancreatic KATP channel isoform (Kir6.2/SUR1). Unlike SUR1, SUR2B subunits adopt distinct rotational “propeller” and “quatrefoil” geometries surrounding their Kir6.1 core. The glutamate/aspartate-rich linker connecting the two halves of the SUR-ABC core is observed in a quatrefoil-like conformation. Molecular dynamics simulations reveal MgADP-dependent dynamic tripartite interactions between this linker, SUR2B, and Kir6.1. The structures captured implicate a progression of intermediate states between MgADP-free inactivated, and MgADP-bound activated conformations wherein the glutamate/aspartate-rich linker participates as mobile autoinhibitory domain, suggesting a conformational pathway toward KATP channel activation.
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Rojo Arias JE, Jászai J. Gene expression profile of the murine ischemic retina and its response to Aflibercept (VEGF-Trap). Sci Rep 2021; 11:15313. [PMID: 34321516 PMCID: PMC8319207 DOI: 10.1038/s41598-021-94500-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 07/05/2021] [Indexed: 02/07/2023] Open
Abstract
Ischemic retinal dystrophies are leading causes of acquired vision loss. Although the dysregulated expression of the hypoxia-responsive VEGF-A is a major driver of ischemic retinopathies, implication of additional VEGF-family members in their pathogenesis has led to the development of multivalent anti-angiogenic tools. Designed as a decoy receptor for all ligands of VEGFR1 and VEGFR2, Aflibercept is a potent anti-angiogenic agent. Notwithstanding, the molecular mechanisms mediating Aflibercept's efficacy remain only partially understood. Here, we used the oxygen-induced retinopathy (OIR) mouse as a model system of pathological retinal vascularization to investigate the transcriptional response of the murine retina to hypoxia and of the OIR retina to Aflibercept. While OIR severely impaired transcriptional changes normally ensuing during retinal development, analysis of gene expression patterns hinted at alterations in leukocyte recruitment during the recovery phase of the OIR protocol. Moreover, the levels of Angiopoietin-2, a major player in the progression of diabetic retinopathy, were elevated in OIR tissues and consistently downregulated by Aflibercept. Notably, GO term, KEGG pathway enrichment, and expression dynamics analyses revealed that, beyond regulating angiogenic processes, Aflibercept also modulated inflammation and supported synaptic transmission. Altogether, our findings delineate novel mechanisms potentially underlying Aflibercept's efficacy against ischemic retinopathies.
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Affiliation(s)
- Jesús Eduardo Rojo Arias
- grid.4488.00000 0001 2111 7257Department of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Saxony, Germany ,grid.5335.00000000121885934Present Address: Wellcome-MRC Cambridge Stem Cell Institute, Jeffrey Cheah Biomedical Centre, Cambridge Biomedical Campus, University of Cambridge, Cambridge, UK
| | - József Jászai
- grid.4488.00000 0001 2111 7257Department of Anatomy, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Saxony, Germany
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Scala R, Maqoud F, Zizzo N, Passantino G, Mele A, Camerino GM, McClenaghan C, Harter TM, Nichols CG, Tricarico D. Consequences of SUR2[A478V] Mutation in Skeletal Muscle of Murine Model of Cantu Syndrome. Cells 2021; 10:cells10071791. [PMID: 34359961 PMCID: PMC8307364 DOI: 10.3390/cells10071791] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 12/18/2022] Open
Abstract
(1) Background: Cantu syndrome (CS) arises from gain-of-function (GOF) mutations in the ABCC9 and KCNJ8 genes, which encode ATP-sensitive K+ (KATP) channel subunits SUR2 and Kir6.1, respectively. Most CS patients have mutations in SUR2, the major component of skeletal muscle KATP, but the consequences of SUR2 GOF in skeletal muscle are unknown. (2) Methods: We performed in vivo and ex vivo characterization of skeletal muscle in heterozygous SUR2[A478V] (SUR2wt/AV) and homozygous SUR2[A478V] (SUR2AV/AV) CS mice. (3) Results: In SUR2wt/AV and SUR2AV/AV mice, forelimb strength and diaphragm amplitude movement were reduced; muscle echodensity was enhanced. KATP channel currents recorded in Flexor digitorum brevis fibers showed reduced MgATP-sensitivity in SUR2wt/AV, dramatically so in SUR2AV/AV mice; IC50 for MgATP inhibition of KATP currents were 1.9 ± 0.5 × 10−5 M in SUR2wt/AV and 8.6 ± 0.4 × 10−6 M in WT mice and was not measurable in SUR2AV/AV. A slight rightward shift of sensitivity to inhibition by glibenclamide was detected in SUR2AV/AV mice. Histopathological and qPCR analysis revealed atrophy of soleus and tibialis anterior muscles and up-regulation of atrogin-1 and MuRF1 mRNA in CS mice. (4) Conclusions: SUR2[A478V] “knock-in” mutation in mice impairs KATP channel modulation by MgATP, markedly so in SUR2AV/AV, with atrophy and non-inflammatory edema in different skeletal muscle phenotypes.
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Affiliation(s)
- Rosa Scala
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Fatima Maqoud
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Nicola Zizzo
- Section of Veterinary Pathology and Comparative Oncology, Department of Veterinary Medicine, University of Bari “Aldo Moro”, 70121 Bari, Italy; (N.Z.); (G.P.)
| | - Giuseppe Passantino
- Section of Veterinary Pathology and Comparative Oncology, Department of Veterinary Medicine, University of Bari “Aldo Moro”, 70121 Bari, Italy; (N.Z.); (G.P.)
| | - Antonietta Mele
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Giulia Maria Camerino
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
| | - Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA; (C.M.); (T.M.H.); (C.G.N.)
| | - Theresa M. Harter
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA; (C.M.); (T.M.H.); (C.G.N.)
| | - Colin G. Nichols
- Center for the Investigation of Membrane Excitability Diseases, Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110-1010, USA; (C.M.); (T.M.H.); (C.G.N.)
| | - Domenico Tricarico
- Section of Pharmacology, Department of Pharmacy-Pharmaceutical Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy; (R.S.); (F.M.); (A.M.); (G.M.C.)
- Correspondence:
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Abstract
ATP-sensitive K+ channels (KATP) are inwardly-rectifying potassium channels, broadly expressed throughout the body. KATP is regulated by adenine nucleotides, characteristically being activated by falling ATP and rising ADP levels thus playing an important physiological role by coupling cellular metabolism with membrane excitability. The hetero-octameric channel complex is formed of 4 pore-forming inward rectifier Kir6.x subunits (Kir6.1 or Kir6.2) and 4 regulatory sulfonylurea receptor subunits (SUR1, SUR2A, or SUR2B). These subunits can associate in various tissue-specific combinations to form functional KATP channels with distinct electrophysiological and pharmacological properties. KATP channels play many important physiological roles and mutations in channel subunits can result in diseases such as disorders of insulin handling, cardiac arrhythmia, cardiomyopathy, and neurological abnormalities. The tissue-specific expression of KATP channel subunits coupled with their rich and diverse pharmacology makes KATP channels attractive therapeutic targets in the treatment of endocrine and cardiovascular diseases.
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Roessler HI, van der Heuvel LM, Shields K, Guilliams KP, Knoers NVAM, van Haaften G, Grange DK, van Haelst MM. Behavioral and cognitive functioning in individuals with Cantú syndrome. Am J Med Genet A 2021; 185:2434-2444. [PMID: 34056838 DOI: 10.1002/ajmg.a.62348] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 04/20/2021] [Accepted: 05/07/2021] [Indexed: 11/07/2022]
Abstract
Cantú syndrome (CS) is caused by pathogenic variants in ABCC9 and KCNJ8 encoding the regulatory and pore-forming subunits of ATP-sensitive potassium (KATP ) channels. CS is characterized by congenital hypertrichosis, distinctive facial features, peripheral edema, and cardiac and neurodevelopmental abnormalities. Behavioral and cognitive issues have been self-reported by some CS individuals, but results of formal standardized investigations have not been published. To assess the cognitive profile, social functioning, and psychiatric symptoms in a large group of CS subjects systematically in a cross-sectional manner, we invited 35 individuals (1-69 years) with confirmed ABCC9 variants and their relatives to complete various commonly applied standardized age-related questionnaires, including the Kaufman brief intelligence test 2, the social responsiveness scale-2, and the Achenbach system of empirically based assessment. The majority of CS individuals demonstrated average verbal and nonverbal intelligence compared to the general population. Fifteen percent of cases showed social functioning strongly associated with a clinical diagnosis of autism spectrum disorder. Both externalizing and internalizing problems were also present in this cohort. In particular, anxiety, anxiety or attention deficit hyperactivity disorder, and autism spectrum behaviors were predominantly observed in the younger subjects in the cohort (≥25%), but this percentage decreased markedly in adults.
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Affiliation(s)
- Helen I Roessler
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Lieke M van der Heuvel
- Department of Clinical Genetics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Kathleen Shields
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kristin P Guilliams
- Division of Pediatric Neurology, Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
- Division of Pediatric Critical Care, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nine V A M Knoers
- Department of Genetics, University Medical Center Groningen, Groningen, The Netherlands
| | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Dorothy K Grange
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for the Investigation of Membrane Excitability Diseases (CIMED), St. Louis, Missouri, USA
| | - Mieke M van Haelst
- Department of Clinical Genetics, Amsterdam University Medical Centers, Amsterdam, The Netherlands
- Department of Clinical Genetics, VU Medical Center, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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Zhang L, Huang P, Huang C, Jiang L, Lu Z, Wang P. Varied clinical significance of ATP-binding cassette C sub-family members for lung adenocarcinoma. Medicine (Baltimore) 2021; 100:e25246. [PMID: 33879658 PMCID: PMC8078454 DOI: 10.1097/md.0000000000025246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 03/01/2021] [Indexed: 12/25/2022] Open
Abstract
Lung adenocarcinoma (LUAD) is a lethal malignancy worldwide and a major public health concern. We explored the potential clinical significance for LUAD of ATP-binding cassette (ABC), sub-family C, consisting of ABCC1-6, 8-12, and cystic fibrosis transmembrane conductance regulator (CFTR).Five hundred LUAD patients from The Cancer Genome Atlas database were used for analysis, including differential expression and diagnostic and prognostic significance. Oncomine and MERAV databases were used to validate differential expression and diagnostic significance. A risk score model was constructed using prognosis-related ABCC members. Prognosis-related genes were further explored to correlate their expression with tumor stage progression. Interaction networks, including biological processes and metabolic pathways, were constructed using Cytoscape software and STRING website.ABCC1-3 consistently showed high expression in tumor tissues (all P ≤ 0.05). Most datasets indicated that ABCC5, 10, and 11 were highly expressed in tumor tissues whereas ABCC6, 9, and CFTR were highly expressed in nontumor tissues (all P ≤ 0.05). Diagnostic significance of ABCC3 and ABCC5 was consistently assessed and validated in three datasets (all area under the curve > 0.700) whereas ABCC6, 8, 10, 11, and CFTR were assessed in The Cancer Genome Atlas dataset and validated in one dataset (all area under the curve > 0.700). Prognostic analysis indicated that ABCC2, 6, and 8 mRNA expression was associated with survival of LUAD (all adjusted P ≤ .037). The risk score model constructed using ABCC2, 6, and 8 suggested prognostic significance for survival predictions. ABCC2 expression was associated with tumor stage, whereas ABCC6 and 8 were not. Interaction networks indicated that they were involved in establishment of localization, ion transport, plasma membrane, apical plasma membrane, adenylyl nucleotide binding, ABC transporters, ABC transporter disorders, ABC-family-protein-mediated transport, and bile secretion.Differentially expressed ABCC2 and ABCC5 might be diagnostic whereas ABCC2, 6, and 8 may be prognostic biomarkers for LUAD, possibly through ABC-family-mediated transporter disorders.
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Vrijenhoek T, Tonisson N, Kääriäinen H, Leitsalu L, Rigter T. Clinical genetics in transition-a comparison of genetic services in Estonia, Finland, and the Netherlands. J Community Genet 2021; 12:277-290. [PMID: 33704686 PMCID: PMC7948164 DOI: 10.1007/s12687-021-00514-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 02/18/2021] [Indexed: 11/25/2022] Open
Abstract
Genetics has traditionally enabled the reliable diagnosis of patients with rare genetic disorders, thus empowering the key role of today's clinical geneticists in providing healthcare. With the many novel technologies that have expanded the genetic toolkit, genetics is increasingly evolving beyond rare disease diagnostics. When placed in a transition context-like we do here-clinical genetics is likely to become a fully integral part of future healthcare and clinical genetic expertise will be required increasingly outside traditional clinical genetic settings. We explore transition effects on the thinking (culture), organizing (structure), and performing (practice) in clinical genetics, taking genetic healthcare in Estonia, Finland, and the Netherlands as examples. Despite clearly distinct healthcare histories, all three countries have initially implemented genetic healthcare in a rather similar fashion: as a diagnostic tool for predominantly rare congenital diseases, with clinical geneticists as the main providers. Dynamics at different levels, such as emerging technologies, biobanks and data infrastructure, and legislative frameworks, may require development of a new system attuned with the demands and (historic) context of specific countries. Here, we provide an overview of genetic service provisions in Estonia, Finland, and the Netherlands to consider the impact of historic and recent events on prospective developments in genetic healthcare.
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Affiliation(s)
- T Vrijenhoek
- Department of Genetics, University Medical Centre Utrecht, Utrecht, The Netherlands
| | - N Tonisson
- Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu, Estonia
- Dept. of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia
| | - H Kääriäinen
- Finnish Institute for Health and Welfare, Helsinki, Finland
| | - L Leitsalu
- Estonian Genome Centre, Institute of Genomics, University of Tartu, Tartu, Estonia
| | - T Rigter
- Department of Clinical Genetics, Section Community Genetics & Amsterdam Public Health Research Institute, Amsterdam University Medical Centre, Location VUmc, Amsterdam, The Netherlands.
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Mondéjar-Parreño G, Cogolludo A, Perez-Vizcaino F. Potassium (K +) channels in the pulmonary vasculature: Implications in pulmonary hypertension Physiological, pathophysiological and pharmacological regulation. Pharmacol Ther 2021; 225:107835. [PMID: 33744261 DOI: 10.1016/j.pharmthera.2021.107835] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 02/06/2023]
Abstract
The large K+ channel functional diversity in the pulmonary vasculature results from the multitude of genes expressed encoding K+ channels, alternative RNA splicing, the post-transcriptional modifications, the presence of homomeric or heteromeric assemblies of the pore-forming α-subunits and the existence of accessory β-subunits modulating the functional properties of the channel. K+ channels can also be regulated at multiple levels by different factors controlling channel activity, trafficking, recycling and degradation. The activity of these channels is the primary determinant of membrane potential (Em) in pulmonary artery smooth muscle cells (PASMC), providing an essential regulatory mechanism to dilate or contract pulmonary arteries (PA). K+ channels are also expressed in pulmonary artery endothelial cells (PAEC) where they control resting Em, Ca2+ entry and the production of different vasoactive factors. The activity of K+ channels is also important in regulating the population and phenotype of PASMC in the pulmonary vasculature, since they are involved in cell apoptosis, survival and proliferation. Notably, K+ channels play a major role in the development of pulmonary hypertension (PH). Impaired K+ channel activity in PH results from: 1) loss of function mutations, 2) downregulation of its expression, which involves transcription factors and microRNAs, or 3) decreased channel current as a result of increased vasoactive factors (e.g., hypoxia, 5-HT, endothelin-1 or thromboxane), exposure to drugs with channel-blocking properties, or by a reduction in factors that positively regulate K+ channel activity (e.g., NO and prostacyclin). Restoring K+ channel expression, its intracellular trafficking and the channel activity is an attractive therapeutic strategy in PH.
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Affiliation(s)
- Gema Mondéjar-Parreño
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain; Ciber Enfermedades Respiratorias (CIBERES), Spain
| | - Angel Cogolludo
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain; Ciber Enfermedades Respiratorias (CIBERES), Spain
| | - Francisco Perez-Vizcaino
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Spain; Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain; Ciber Enfermedades Respiratorias (CIBERES), Spain.
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47
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Zhang H, Hanson A, de Almeida TS, Emfinger C, McClenaghan C, Harter T, Yan Z, Cooper PE, Brown GS, Arakel EC, Mecham RP, Kovacs A, Halabi CM, Schwappach B, Remedi MS, Nichols CG. Complex consequences of Cantu syndrome SUR2 variant R1154Q in genetically modified mice. JCI Insight 2021; 6:145934. [PMID: 33529173 PMCID: PMC8021106 DOI: 10.1172/jci.insight.145934] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Accepted: 01/27/2021] [Indexed: 01/10/2023] Open
Abstract
Cantu syndrome (CS) is caused by gain-of-function (GOF) mutations in pore-forming (Kir6.1, KCNJ8) and accessory (SUR2, ABCC9) ATP-sensitive potassium (KATP) channel subunits, the most common mutations being SUR2[R1154Q] and SUR2[R1154W], carried by approximately 30% of patients. We used CRISPR/Cas9 genome engineering to introduce the equivalent of the human SUR2[R1154Q] mutation into the mouse ABCC9 gene. Along with minimal CS disease features, R1154Q cardiomyocytes and vascular smooth muscle showed much lower KATP current density and pinacidil activation than WT cells. Almost complete loss of SUR2-dependent protein and KATP in homozygous R1154Q ventricles revealed underlying diazoxide-sensitive SUR1-dependent KATP channel activity. Surprisingly, sequencing of SUR2 cDNA revealed 2 distinct transcripts, one encoding full-length SUR2 protein; and the other with an in-frame deletion of 93 bases (corresponding to 31 amino acids encoded by exon 28) that was present in approximately 40% and approximately 90% of transcripts from hetero- and homozygous R1154Q tissues, respectively. Recombinant expression of SUR2A protein lacking exon 28 resulted in nonfunctional channels. CS tissue from SUR2[R1154Q] mice and human induced pluripotent stem cell-derived (hiPSC-derived) cardiomyocytes showed only full-length SUR2 transcripts, although further studies will be required in order to fully test whether SUR2[R1154Q] or other CS mutations might result in aberrant splicing and variable expressivity of disease features in human CS.
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Affiliation(s)
- Haixia Zhang
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Alex Hanson
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Tobias Scherf de Almeida
- Department of Molecular Biology, Center for Biochemistry and Molecular Cell Biology, Heart Research Center Göttingen, University Medicine Göttingen, Göttingen, Germany
| | - Christopher Emfinger
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Theresa Harter
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Zihan Yan
- Center for the Investigation of Membrane Excitability Diseases and.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research
| | - Paige E Cooper
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - G Schuyler Brown
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Eric C Arakel
- Department of Molecular Biology, Center for Biochemistry and Molecular Cell Biology, Heart Research Center Göttingen, University Medicine Göttingen, Göttingen, Germany
| | - Robert P Mecham
- Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | | | - Carmen M Halabi
- Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Blanche Schwappach
- Department of Molecular Biology, Center for Biochemistry and Molecular Cell Biology, Heart Research Center Göttingen, University Medicine Göttingen, Göttingen, Germany
| | - Maria S Remedi
- Center for the Investigation of Membrane Excitability Diseases and.,DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases and.,Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
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48
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Mani I. Genome editing in cardiovascular diseases. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 181:289-308. [PMID: 34127197 DOI: 10.1016/bs.pmbts.2021.01.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Genetic modification at the molecular level in somatic cells, germline, and animal models requires for different purposes, such as introducing desired mutation, deletion of alleles, and insertion of novel genes in the genome. Various genome-editing tools are available to accomplish these alterations, such as zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated (Cas) system. CRISPR-Cas system is an emerging technology, which is being used in biological and medical sciences, including in the cardiovascular field. It assists to identify the mechanism of various cardiovascular disease occurrence, such as hypertrophic cardiomyopathy (HCM), dilated cardiomyopathy (DCM), and arrhythmogenic cardiomyopathy (ACM). Furthermore, it has been advantages to edit various genes simultaneously and can also be used to treat and prevent several human diseases. This chapter explores the use of the scientific and therapeutic potential of a CRISPR-Cas system to edit the various cardiovascular disease-associated genes to understand the pathways involved in disease progression and treatment.
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Affiliation(s)
- Indra Mani
- Department of Microbiology, Gargi College, University of Delhi, New Delhi, India.
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49
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Gripp KW, Smithson SF, Scurr IJ, Baptista J, Majumdar A, Pierre G, Williams M, Henderson LB, Wentzensen IM, McLaughlin H, Leeuwen L, Simon MEH, van Binsbergen E, Dinulos MBP, Kaplan JD, McRae A, Superti-Furga A, Good JM, Kutsche K. Syndromic disorders caused by gain-of-function variants in KCNH1, KCNK4, and KCNN3-a subgroup of K + channelopathies. Eur J Hum Genet 2021; 29:1384-1395. [PMID: 33594261 PMCID: PMC8440610 DOI: 10.1038/s41431-021-00818-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 01/18/2021] [Accepted: 01/22/2021] [Indexed: 12/13/2022] Open
Abstract
Decreased or increased activity of potassium channels caused by loss-of-function and gain-of-function (GOF) variants in the corresponding genes, respectively, underlies a broad spectrum of human disorders affecting the central nervous system, heart, kidney, and other organs. While the association of epilepsy and intellectual disability (ID) with variants affecting function in genes encoding potassium channels is well known, GOF missense variants in K+ channel encoding genes in individuals with syndromic developmental disorders have only recently been recognized. These syndromic phenotypes include Zimmermann–Laband and Temple–Baraitser syndromes, caused by dominant variants in KCNH1, FHEIG syndrome due to dominant variants in KCNK4, and the clinical picture associated with dominant variants in KCNN3. Here we review the presentation of these individuals, including five newly reported with variants in KCNH1 and three additional individuals with KCNN3 variants, all variants likely affecting function. There is notable overlap in the phenotypic findings of these syndromes associated with dominant KCNN3, KCNH1, and KCNK4 variants, sharing developmental delay and/or ID, coarse facial features, gingival enlargement, distal digital hypoplasia, and hypertrichosis. We suggest to combine the phenotypes and define a new subgroup of potassium channelopathies caused by increased K+ conductance, referred to as syndromic neurodevelopmental K+ channelopathies due to dominant variants in KCNH1, KCNK4, or KCNN3.
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Affiliation(s)
- Karen W Gripp
- Division of Medical Genetics, Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Sarah F Smithson
- Department of Clinical Genetics, University Hospitals Bristol and Weston, Bristol, UK
| | - Ingrid J Scurr
- Department of Clinical Genetics, University Hospitals Bristol and Weston, Bristol, UK
| | - Julia Baptista
- Exeter Genomics Laboratory, Royal Devon & Exeter NHS Foundation Trust, Exeter, UK.,College of Medicine and Health, University of Exeter, Exeter, UK
| | - Anirban Majumdar
- Department of Paediatric Neurology, Bristol Royal Hospital for Children, Bristol, UK
| | - Germaine Pierre
- Department of Paediatric Metabolic Medicine, Bristol Royal Hospital for Children, Bristol, UK
| | - Maggie Williams
- Bristol Genetics Laboratory, North Bristol NHS Trust, Bristol, UK
| | | | | | | | - Lisette Leeuwen
- Department of Genetics, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Marleen E H Simon
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ellen van Binsbergen
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Mary Beth P Dinulos
- Section of Genetics and Child Development, Children's Hospital at Dartmouth, Lebanon, NH, USA
| | - Julie D Kaplan
- Division of Medical Genetics, Alfred I. duPont Hospital for Children, Wilmington, DE, USA
| | - Anne McRae
- Division of Genetics, Birth Defects and Metabolism, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Andrea Superti-Furga
- Division of Genetic Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Jean-Marc Good
- Division of Genetic Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Kerstin Kutsche
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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50
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Garner BR, Stolarz AJ, Stuckey D, Sarimollaoglu M, Liu Y, Palade PT, Rusch NJ, Mu S. K ATP Channel Openers Inhibit Lymphatic Contractions and Lymph Flow as a Possible Mechanism of Peripheral Edema. J Pharmacol Exp Ther 2021; 376:40-50. [PMID: 33100270 PMCID: PMC7745085 DOI: 10.1124/jpet.120.000121] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 10/08/2020] [Indexed: 11/22/2022] Open
Abstract
Pharmacological openers of ATP-sensitive potassium (KATP) channels are effective antihypertensive agents, but off-target effects, including severe peripheral edema, limit their clinical usefulness. It is presumed that the arterial dilation induced by KATP channel openers (KCOs) increases capillary pressure to promote filtration edema. However, KATP channels also are expressed by lymphatic muscle cells (LMCs), raising the possibility that KCOs also attenuate lymph flow to increase interstitial fluid. The present study explored the effect of KCOs on lymphatic contractile function and lymph flow. In isolated rat mesenteric lymph vessels (LVs), the prototypic KATP channel opener cromakalim (0.01-3 µmol/l) progressively inhibited rhythmic contractions and calculated intraluminal flow. Minoxidil sulfate and diazoxide (0.01-100 µmol/l) had similar effects at clinically relevant plasma concentrations. High-speed in vivo imaging of the rat mesenteric lymphatic circulation revealed that superfusion of LVs with cromakalim and minoxidil sulfate (0.01-10 µmol/l) maximally decreased lymph flow in vivo by 38.4% and 27.4%, respectively. Real-time polymerase chain reaction and flow cytometry identified the abundant KATP channel subunits in LMCs as the pore-forming Kir6.1/6.2 and regulatory sulfonylurea receptor 2 subunits. Patch-clamp studies detected cromakalim-elicited unitary K+ currents in cell-attached patches of LMCs with a single-channel conductance of 46.4 pS, which is a property consistent with Kir6.1/6.2 tetrameric channels. Addition of minoxidil sulfate and diazoxide elicited unitary currents of similar amplitude. Collectively, our findings indicate that KCOs attenuate lymph flow at clinically relevant plasma concentrations as a potential contributing mechanism to peripheral edema. SIGNIFICANCE STATEMENT: ATP-sensitive potassium (KATP) channel openers (KCOs) are potent antihypertensive medications, but off-target effects, including severe peripheral edema, limit their clinical use. Here, we demonstrate that KCOs impair the rhythmic contractions of lymph vessels and attenuate lymph flow, which may promote edema formation. Our finding that the KATP channels in lymphatic muscle cells may be unique from their counterparts in arterial muscle implies that designing arterial-selective KCOs may avoid activation of lymphatic KATP channels and peripheral edema.
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Affiliation(s)
- Brittney R Garner
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Amanda J Stolarz
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Daniel Stuckey
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Mustafa Sarimollaoglu
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Yunmeng Liu
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Philip T Palade
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Nancy J Rusch
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
| | - Shengyu Mu
- Department of Pharmacology and Toxicology (B.R.G., A.J.S., D.S., Y.L., P.T.P., N.J.R., S.M.) and Arkansas Nanomedicine Center (M.S.), College of Medicine and Department of Pharmaceutical Sciences, College of Pharmacy (A.J.S.), University of Arkansas for Medical Sciences, Little Rock, Arkansas
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