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Gil-Rivera M, Medina-Gali RM, Martínez-Pinna J, Soriano S. Physiology of pancreatic β-cells: Ion channels and molecular mechanisms implicated in stimulus-secretion coupling. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:287-323. [PMID: 33832651 DOI: 10.1016/bs.ircmb.2021.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The human and mouse islet of Langerhans is an endocrine organ composed of five different cells types; insulin-secreting β-cells, glucagon-producing α-cells, somatostatin-producing δ-cells, pancreatic polypeptide-secreting PP cells and ɛ-cells that secretes ghrelin. The most important cells are the pancreatic β-cells that comprise around 45-50% of human islets and 75-80% in the mouse. Pancreatic β-cells secrete insulin at high glucose concentration, thereby finely regulating glycaemia by the hypoglycaemic effects of this hormone. Different ion channels are implicated in the stimulus-secretion coupling of insulin. An increase in the intracellular ATP concentration leads to closure KATP channels, depolarizing the cell and opening voltage-gated calcium channels. The increase of intracellular calcium concentration induced by calcium entry through voltage-gated calcium channels promotes insulin secretion. Here, we briefly describe the diversity of ion channels present in pancreatic β-cells and the different mechanisms that are responsible to induce insulin secretion in human and mouse cells. Moreover, we described the pathophysiology due to alterations in the physiology of the main ion channels present in pancreatic β-cell and its implication to predispose metabolic disorders as type 2 diabetes mellitus.
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Affiliation(s)
- Minerva Gil-Rivera
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain.
| | - Regla M Medina-Gali
- Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid, Spain; Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, Elche, Spain
| | - Juan Martínez-Pinna
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain; Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, Elche, Spain
| | - Sergi Soriano
- Departamento de Fisiología, Genética y Microbiología, Universidad de Alicante, Alicante, Spain; Instituto de Investigación, Desarrollo e Innovación en Biotecnología Sanitaria de Elche (IDiBE), Universidad Miguel Hernández, Elche, Spain.
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102
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Giannopoulou EZ, Ovcarov O, De Franco E, Kassberger F, Nusser S, Otto MC, Denzer C, Wabitsch M. Transient neonatal diabetes due to a disease causing novel variant in the ATP-binding cassette subfamily C member 8 ( ABCC8) gene unmasks maturity-onset diabetes of the young (MODY) diabetes cases within a family. J Pediatr Endocrinol Metab 2021; 34:273-276. [PMID: 33185579 DOI: 10.1515/jpem-2020-0462] [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: 08/06/2020] [Accepted: 09/26/2020] [Indexed: 11/15/2022]
Abstract
OBJECTIVES Neonatal diabetes mellitus (NDM) is a rare monogenic diabetes form, occurring mainly from ATP-binding cassette subfamily C member 8 (ABCC8) and KCNJ11 mutations. ABCC8 mutations have also been found to cause adult-onset diabetes. What is new?: •Novel ABCC8 mutation in an NDM case •Heterogeneous clinical presentation of diabetes and response to sulfonylurea therapy among family members with the same ABCC8 mutation. CASE PRESENTATION We report the case of a newborn with NDM and a heterozygous ABCC8 novel variant (c.3835G>A), successfully treated with sulfonylurea. The same ABCC8 variant was found in two other family members, already treated for type 2 diabetes. CONCLUSIONS This case demonstrates the variable phenotypic presentation of diabetes due to a novel ABCC8 mutation (c.3835G>A), ranging from transient NDM to adult-onset, insulin-demanding diabetes, among family members. Genetic testing in young individuals with a strong family history of diabetes, presenting with non-autoimmune diabetes is recommended as it can determine prognosis and treatment of affected family members.
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Affiliation(s)
- Eleni Z Giannopoulou
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Endocrinology and Diabetes, Ulm University, Ulm, Germany
| | - Olga Ovcarov
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Endocrinology and Diabetes, Ulm University, Ulm, Germany
| | - Elisa De Franco
- College of Medicine and Health, University of Exeter Medical School, Exeter, UK
| | - Fabian Kassberger
- Department of Pediatrics and Adolescent Medicine, Klinikum Göppingen, Göppingen, Germany
| | - Susanne Nusser
- Department of Pediatrics and Adolescent Medicine, Klinikum Göppingen, Göppingen, Germany
| | - Marie Celine Otto
- Department of Pediatrics and Adolescent Medicine, Klinikum Göppingen, Göppingen, Germany
| | - Christian Denzer
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Endocrinology and Diabetes, Ulm University, Ulm, Germany
| | - Martin Wabitsch
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Endocrinology and Diabetes, Ulm University, Ulm, Germany
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103
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Oduori OS, Murao N, Shimomura K, Takahashi H, Zhang Q, Dou H, Sakai S, Minami K, Chanclon B, Guida C, Kothegala L, Tolö J, Maejima Y, Yokoi N, Minami Y, Miki T, Rorsman P, Seino S. Gs/Gq signaling switch in β cells defines incretin effectiveness in diabetes. J Clin Invest 2021; 130:6639-6655. [PMID: 33196462 DOI: 10.1172/jci140046] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/03/2020] [Indexed: 12/15/2022] Open
Abstract
By restoring glucose-regulated insulin secretion, glucagon-like peptide-1-based (GLP-1-based) therapies are becoming increasingly important in diabetes care. Normally, the incretins GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) jointly maintain normal blood glucose levels by stimulation of insulin secretion in pancreatic β cells. However, the reason why only GLP-1-based drugs are effective in improving insulin secretion after presentation of diabetes has not been resolved. ATP-sensitive K+ (KATP) channels play a crucial role in coupling the systemic metabolic status to β cell electrical activity for insulin secretion. Here, we have shown that persistent membrane depolarization of β cells due to genetic (β cell-specific Kcnj11-/- mice) or pharmacological (long-term exposure to sulfonylureas) inhibition of the KATP channel led to a switch from Gs to Gq in a major amplifying pathway of insulin secretion. The switch determined the relative insulinotropic effectiveness of GLP-1 and GIP, as GLP-1 can activate both Gq and Gs, while GIP only activates Gs. The findings were corroborated in other models of persistent depolarization: a spontaneous diabetic KK-Ay mouse and nondiabetic human and mouse β cells of pancreatic islets chronically treated with high glucose. Thus, a Gs/Gq signaling switch in β cells exposed to chronic hyperglycemia underlies the differential insulinotropic potential of incretins in diabetes.
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Affiliation(s)
- Okechi S Oduori
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Naoya Murao
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kenju Shimomura
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Haiqiang Dou
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Shihomi Sakai
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kohtaro Minami
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Belen Chanclon
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Claudia Guida
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Lakshmi Kothegala
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Johan Tolö
- Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Yuko Maejima
- Department of Bioregulation and Pharmacological Medicine, Fukushima Medical University School of Medicine, Fukushima, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.,Laboratory of Animal Breeding and Genetics, Division of Applied Biosciences, Kyoto University Graduate School of Agriculture, Kyoto, Japan
| | - Yasuhiro Minami
- Division of Cell Physiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takashi Miki
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,Metabolic Research Unit, Institute of Neuroscience and Physiology, University of Gothenburg, Gothenburg, Sweden
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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104
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Yildirim C, Özkaya B, Bal R. KATP and TRPM2-like channels couple metabolic status to resting membrane potential of octopus neurons in the mouse ventral cochlear nucleus. Brain Res Bull 2021; 170:115-128. [PMID: 33581312 DOI: 10.1016/j.brainresbull.2021.02.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 02/04/2021] [Accepted: 02/06/2021] [Indexed: 12/29/2022]
Abstract
ATP-sensitive potassium (KATP) channels and transient receptor potential melastatin 2 (TRPM2) channels are commonly expressed both pre- and postsynaptically in the central nervous system (CNS). We hypothesized that KATP and TRPM2 may couple metabolic status to the resting membrane potential of octopus neurons of the mouse ventral cochlear nucleus (VCN). Therefore, we studied the expression of KATP channels and TRPM2 channels in octopus cells by immunohistochemical techniques and their contribution to neuronal electrical properties by the electrophysiological patch clamp technique. In immunohistochemical staining of octopus cells, labelling with Kir6.2 and SUR1 antibodies was strong, and labelling with the SUR2 antibody was moderate, but labelling with Kir6.1 was very weak. Octopus cells had intense staining with TRPM2 antibodies. In patch clamp recordings, bath application of KATP channel agonists H2O2 (880 μM), ATZ (1 mM), cromakalim (50 μM), diazoxide (200 μM), NNC 55-0118 and NN 414 separately resulted in hyperpolarizations of resting potential to different extents. Application of 8-Bro-cADPR (50 μM), a specific antagonist of TRPM2 channels, in the presence of H2O2 (880 μM) resulted in further hyperpolarization by approximately 1 mV. The amplitudes of H2O2-induced outward KATP currents and ADPR-induced inward currents were 206.1 ± 31.5 pA (n = 4) and 136.8 ± 22.4 pA, respectively, at rest. Their respective reversal potentials were -77 ± 2.6 mV (n = 3) and -6.3 ± 2.9 (n = 3) and -6.3 ± 2.9 (n = 3). In conclusion, octopus cells appear to possess both KATP channels and TRPM2-like channels. KATP might largely be constituted by SUR1-Kir6.2 subunits and SUR2-Kir6.2 subunits. Both KATP and TRPM2-like channels might have a modulatory action in setting the membrane potential.
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Affiliation(s)
- Caner Yildirim
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Beytullah Özkaya
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey
| | - Ramazan Bal
- Department of Physiology, Faculty of Medicine, Gaziantep University, 27310, Gaziantep, Turkey.
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105
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Gopi S, Kavitha B, Kanthimathi S, Kannan A, Kumar R, Joshi R, Kanodia S, Arya AD, Pendsey S, Pendsey S, Raghupathy P, Mohan V, Radha V. Genotype-phenotype correlation of K ATP channel gene defects causing permanent neonatal diabetes in Indian patients. Pediatr Diabetes 2021; 22:82-92. [PMID: 32893419 DOI: 10.1111/pedi.13109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 08/06/2020] [Accepted: 08/23/2020] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND There are very few reports pertaining to Indian patients with neonatal diabetes mellitus (NDM). Activating or gain of function mutations of KATP channel genes namely KCNJ11 and ABCC8 are most predominant cause of permanent neonatal diabetes mellitus (PNDM). OBJECTIVES To identify the genotype-phenotype correlation of KATP channel gene defects in a large series of (n = 181) Indian PNDM patients. METHODS Direct sequencing of all exons of KCNJ11 and ABCC8 genes in all 181 patients with PNDM were performed. Clinical and biochemical data were collected. RESULTS We have identified the molecular basis of KATP -NDM in 39 out of 181 patients (22%). Of these, 20 had KCNJ11 mutations and 19 had ABCC8 mutations, thus comprising 51% of KCNJ11 and 49% of ABCC8. There were four novel mutations (D1128Tfs*16, Y1287C, S1422T, and H1537R) in ABCC8 gene. Three patients with KCNJ11 mutations had developmental delay with DEND syndrome. In patients with ABCC8 mutations developmental delay was seen in seven out of 19 (36.8%). Of this, three patients (15.7%) had DEND phenotype and four (21%) had iDEND. Of the 39 patients, 33 (84%) patients were shifted to sulfonylurea therapy (glibenclamide). Of this, 19(57.5%) patients harbored KCNJ11 mutations and 14(42.1%) ABCC8 mutations. CONCLUSIONS This is the first largest study in NDM patients in India demonstrating the importance of KATP channel gene mutation screening in PNDM and efficacy of glibenclamide for Indian patients with KATP -PNDM. The success rate of transfer is more in patients with KCNJ11 mutations compared with those with ABCC8 mutations.
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Affiliation(s)
- Sundaramoorthy Gopi
- Department of Molecular Genetics, Madras Diabetes Research Foundation, ICMR Advanced Centre for Genomics of Type 2 Diabetes, Affiliated to University of Madras, Chennai, India
| | - Babu Kavitha
- Department of Molecular Genetics, Madras Diabetes Research Foundation, ICMR Advanced Centre for Genomics of Type 2 Diabetes, Affiliated to University of Madras, Chennai, India
| | - Sekar Kanthimathi
- Department of Molecular Genetics, Madras Diabetes Research Foundation, ICMR Advanced Centre for Genomics of Type 2 Diabetes, Affiliated to University of Madras, Chennai, India
| | - Alagarsamy Kannan
- Dr. Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-Communicable Diseases Prevention & Control, IDF Centre of Education, Chennai, India
| | - Rakesh Kumar
- Advanced Paediatrics Centre, Post-Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Rajesh Joshi
- Division of Paediatric Endocrinology, B.J. Wadia Hospital for Children, Mumbai, India
| | | | - Archana Dayal Arya
- Institute of Child Health, Sir Ganga Ram Hospital Marg, New Delhi, India
| | | | | | | | - Viswanathan Mohan
- Dr. Mohan's Diabetes Specialities Centre, WHO Collaborating Centre for Non-Communicable Diseases Prevention & Control, IDF Centre of Education, Chennai, India.,Department of Diabetology, Madras Diabetes Research Foundation, Chennai, India
| | - Venkatesan Radha
- Department of Molecular Genetics, Madras Diabetes Research Foundation, ICMR Advanced Centre for Genomics of Type 2 Diabetes, Affiliated to University of Madras, Chennai, India
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106
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Ježek P, Holendová B, Jabůrek M, Tauber J, Dlasková A, Plecitá-Hlavatá L. The Pancreatic β-Cell: The Perfect Redox System. Antioxidants (Basel) 2021; 10:antiox10020197. [PMID: 33572903 PMCID: PMC7912581 DOI: 10.3390/antiox10020197] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/20/2021] [Accepted: 01/25/2021] [Indexed: 12/12/2022] Open
Abstract
Pancreatic β-cell insulin secretion, which responds to various secretagogues and hormonal regulations, is reviewed here, emphasizing the fundamental redox signaling by NADPH oxidase 4- (NOX4-) mediated H2O2 production for glucose-stimulated insulin secretion (GSIS). There is a logical summation that integrates both metabolic plus redox homeostasis because the ATP-sensitive K+ channel (KATP) can only be closed when both ATP and H2O2 are elevated. Otherwise ATP would block KATP, while H2O2 would activate any of the redox-sensitive nonspecific calcium channels (NSCCs), such as TRPM2. Notably, a 100%-closed KATP ensemble is insufficient to reach the -50 mV threshold plasma membrane depolarization required for the activation of voltage-dependent Ca2+ channels. Open synergic NSCCs or Cl- channels have to act simultaneously to reach this threshold. The resulting intermittent cytosolic Ca2+-increases lead to the pulsatile exocytosis of insulin granule vesicles (IGVs). The incretin (e.g., GLP-1) amplification of GSIS stems from receptor signaling leading to activating the phosphorylation of TRPM channels and effects on other channels to intensify integral Ca2+-influx (fortified by endoplasmic reticulum Ca2+). ATP plus H2O2 are also required for branched-chain ketoacids (BCKAs); and partly for fatty acids (FAs) to secrete insulin, while BCKA or FA β-oxidation provide redox signaling from mitochondria, which proceeds by H2O2 diffusion or hypothetical SH relay via peroxiredoxin "redox kiss" to target proteins.
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107
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Maqoud F, Scala R, Hoxha M, Zappacosta B, Tricarico D. ATP-sensitive potassium channel subunits in the neuroinflammation: novel drug targets in neurodegenerative disorders. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2021; 21:130-149. [PMID: 33463481 DOI: 10.2174/1871527320666210119095626] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/07/2020] [Accepted: 08/28/2020] [Indexed: 11/22/2022]
Abstract
Arachidonic acids and its metabolites modulate plenty of ligand-gated, voltage-dependent ion channels, and metabolically regulated potassium channels including ATP-sensitive potassium channels (KATP). KATP channels are hetero-multimeric complexes of sulfonylureas receptors (SUR1, SUR2A or SUR2B) and the pore-forming subunits (Kir6.1 and Kir6.2) likewise expressed in the pre-post synapsis of neurons and inflammatory cells, thereby affecting their proliferation and activity. KATP channels are involved in amyloid-β (Aβ)-induced pathology, therefore emerging as therapeutic targets against Alzheimer's and related diseases. The modulation of these channels can represent an innovative strategy for the treatment of neurodegenerative disorders; nevertheless, the currently available drugs are not selective for brain KATP channels and show contrasting effects. This phenomenon can be a consequence of the multiple physiological roles of the different varieties of KATP channels. Openings of cardiac and muscular KATP channel subunits, is protective against caspase-dependent atrophy in these tissues and some neurodegenerative disorders, whereas in some neuroinflammatory diseases benefits can be obtained through the inhibition of neuronal KATP channel subunits. For example, glibenclamide exerts an anti-inflammatory effect in respiratory, digestive, urological, and central nervous system (CNS) diseases, as well as in ischemia-reperfusion injury associated with abnormal SUR1-Trpm4/TNF-α or SUR1-Trpm4/ Nos2/ROS signaling. Despite this strategy is promising, glibenclamide may have limited clinical efficacy due to its unselective blocking action of SUR2A/B subunits also expressed in cardiovascular apparatus with pro-arrhythmic effects and SUR1 expressed in pancreatic beta cells with hypoglycemic risk. Alternatively, neuronal selective dual modulators showing agonist/antagonist actions on KATP channels can be an option.
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Affiliation(s)
- Fatima Maqoud
- Department of Pharmacy-Pharmaceutical Science, University of Bari Aldo Moro, via Orabona 4, 70125-I. Italy
| | - Rosa Scala
- Department of Pharmacy-Pharmaceutical Science, University of Bari Aldo Moro, via Orabona 4, 70125-I. Italy
| | - Malvina Hoxha
- Department of Chemical-Toxicological and Pharmacological Evaluation of Drugs, Faculty of Pharmacy, "Catholic University Our Lady of Good Counsel", Tirana. Albania
| | - Bruno Zappacosta
- Department of Chemical-Toxicological and Pharmacological Evaluation of Drugs, Faculty of Pharmacy, "Catholic University Our Lady of Good Counsel", Tirana. Albania
| | - Domenico Tricarico
- Department of Pharmacy-Pharmaceutical Science, University of Bari Aldo Moro, via Orabona 4, 70125-I. Italy
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108
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Strazza PS, de Siqueira DVF, Leão RM. ATP-sensitive K + channels control the spontaneous firing of a glycinergic interneuron in the auditory brainstem. J Physiol 2021; 599:1611-1630. [PMID: 33369743 DOI: 10.1113/jp280233] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/16/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Cartwheel neurons provide potent inhibition to fusiform neurons in the dorsal cochlear nucleus (DCN). Most cartwheel neurons fire action potentials spontaneously, but the ion channels responsible for this intrinsic activity are unknown. We investigated the ion channels responsible for the intrinsic firing of cartwheel neurons and the stable resting membrane potential found in a fraction of these neurons (quiet neurons). Among the ion channels controlling membrane potential of cartwheel neurons, the presence of open ATP-sensitive potassium channels (KATP ) is responsible for the existence of quiet neurons. Our results pinpoint KATP channel modulation as a critical factor controlling the firing of cartwheel neurons. Hence, it is a crucial channel influencing the balance of excitation and inhibition in the DCN. ABSTRACT Cartwheel neurons from the dorsal cochlear nucleus (DCN) are glycinergic interneurons and the primary source of inhibition on the fusiform neurons, the DCN's principal excitatory neuron. Most cartwheel neurons present spontaneous firing (active neurons), producing a steady inhibitory tone on fusiform neurons. In contrast, a small fraction of these neurons do not fire spontaneously (quiet neurons). Hyperactivity of fusiform neurons is seen in animals with behavioural evidence of tinnitus. Because of its relevance in controlling the excitability of fusiform neurons, we investigated the ion channels responsible for the spontaneous firing of cartwheel neurons in DCN slices from rats. We found that quiet neurons presented an outward conductance not seen in active neurons, which generates a stable resting potential. This current was sensitive to tolbutamide, an ATP-sensitive potassium channel (KATP ) antagonist. After inhibition with tolbutamide, quiet neurons start to fire spontaneously, while the active neurons were not affected. On the other hand, in active neurons, KATP agonist diazoxide activated a conductance similar to quiet neurons' KATP conductance and stopped spontaneous firing. According to the effect of KATP channels on cartwheel neuron firing, glycinergic neurotransmission in DCN was increased by tolbutamide and decreased by diazoxide. Our results reveal a role of KATP channels in controlling the spontaneous firing of neurons not involved in fuel homeostasis.
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Affiliation(s)
- Paulo S Strazza
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Daniela V F de Siqueira
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Ricardo M Leão
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, SP, Brazil
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109
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Zhao S, Wang M, Ma Z. Therapeutic potential of ATP-sensitive potassium channels in Parkinson's disease. Brain Res Bull 2021; 169:1-7. [PMID: 33434622 DOI: 10.1016/j.brainresbull.2021.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 12/19/2020] [Accepted: 01/04/2021] [Indexed: 11/19/2022]
Abstract
In the past decade, there was an increasing interest in the therapeutic potential targeting ATP-sensitive potassium (KATP) channels for an effective treatment of Parkinson's disease (PD). KATP channels are widely expressed in the central nervous system and were reported to mediate the degeneration and death of nigral dopamine neurons in the pathogenesis of PD. This review aims to address the pivotal roles of KATP channels played in the mechanisms underlying PD pathogenesis, and provide possible directions for further research from different perspectives, such as the vulnerability of dopamine neurons in the substantia nigra, neurotransmitter releasing, iron metabolism in the brain, α-synuclein secretion and mitochondrial dysfunction, which are off critical importance in the investigation of KATP channels-targeted precise therapeutic interventions for PD.
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Affiliation(s)
- Sha Zhao
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - MengZhen Wang
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China
| | - ZeGang Ma
- Department of Physiology, School of Basic Medicine, Qingdao University, Qingdao, China; Institute of Brain Science and Disorders, Qingdao University, Qingdao, China.
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110
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Liu G, Fu D, Tian H, Dai A. The mechanism of ions in pulmonary hypertension. Pulm Circ 2021; 11:2045894020987948. [PMID: 33614016 PMCID: PMC7869166 DOI: 10.1177/2045894020987948] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022] Open
Abstract
Pulmonary hypertension(PH)is a kind of hemodynamic and pathophysiological state, in which the pulmonary artery pressure (PAP) rises above a certain threshold. The main pathological manifestation is pulmonary vasoconstriction and remodelling progressively. More and more studies have found that ions play a major role in the pathogenesis of PH. Many vasoactive substances, inflammatory mediators, transcription-inducing factors, apoptosis mediators, redox substances and translation modifiers can control the concentration of ions inside and outside the cell by regulating the activity of ion channels, which can regulate vascular contraction, cell proliferation, migration, apoptosis, inflammation and other functions. We all know that there are no effective drugs to treat PH. Ions are involved in the occurrence and development of PH, so it is necessary to clarify the mechanism of ions in PH as a therapeutic target for PH. The main ions involved in PH are calcium ion (Ca2+), potassium ion (K+), sodium ion (Na+) and chloride ion (Cl-). Here, we mainly discuss the distribution of these ions and their channels in pulmonary arteries and their role in the pathogenesis of PH.
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Affiliation(s)
- Guogu Liu
- Department of Graduate School, University of South China,
Hengyang, China
- Department of Respiratory Medicine, Hunan Provincial People’s
Hospital, Changsha, China
| | - Daiyan Fu
- Department of Respiratory Medicine, Hunan Provincial People’s
Hospital, Changsha, China
| | - Heshen Tian
- Department of Graduate School, University of South China,
Hengyang, China
- Department of Respiratory Medicine, Hunan Provincial People’s
Hospital, Changsha, China
| | - Aiguo Dai
- Department of Respiratory Diseases, Hunan University of Chinese
Medicine, Changsha, China
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111
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Tang C, Meng L, Zhang P, Liang X, Dang C, Liang H, Wu J, Lan H, Qin Y. Case Report: A Novel ABCC8 Variant in a Chinese Pedigree of Maturity-Onset Diabetes of the Young. Front Endocrinol (Lausanne) 2021; 12:758723. [PMID: 35002955 PMCID: PMC8734027 DOI: 10.3389/fendo.2021.758723] [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: 08/14/2021] [Accepted: 11/30/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND We aimed to analyze a novel ABCC8 variant of a Chinese patient with suspected maturity-onset diabetes of the young (MODY) and to provide evidence for precise diagnosis and appropriate treatment. METHOD A Chinese family with suspected MODY was recruited in this study, which included a 15-year-old female patient with diabetes. Clinical data and blood samples were collected from the proband and other family members. All of the living relatives were given an oral glucose tolerance test. Next-generation sequencing was performed to identify the mutated genes in the proband. Sanger sequencing was utilized to confirm the location of the pathogenic variant in all subjects. Further treatment was referred to targeted family members according to genetic testing. RESULTS The proband was found to have a random blood glucose level of 244.8 mg/dl and an HbA1c level of 9.2%. Before this investigation, her grandparents had been diagnosed with diabetes. The second uncle, two aunts, mother, and cousin of the proband were diagnosed with diabetes by abnormal HbA1C (6.5-12.1%) and fasting blood glucose (FBG, 91.4-189.7 mg/dl). The second aunt of the proband had impaired glucose homeostasis (HbA1C = 6.4% and FBG = 88.0 mg/dl). One novel missense variant c.1432G>A (p.A478T) in exon 9 of the ABCC8 gene was detected in the proband with suspected MODY. The variant was also found in six family members with diabetes or impaired glucose homeostasis, including her second uncle, two aunts, mother, and cousin. After the treatment was switched to glimepiride, the fasting blood glucose was adjusted to 99.54 mg/dl, the 2-h postprandial blood glucose was 153.54 mg/dl, serum fructosamine was 259 μmol/l, and HbA1c was 5.8%. The glycemic control remained optimal, and no hypoglycemic episodes were observed in the living relatives. CONCLUSION This study revealed one novel missense variant of the ABCC8 gene in Chinese families. The present findings indicated that the members of this family responded to treatment with sulfonylureas as previously seen in ABCC8 MODY.
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Affiliation(s)
- Chaoyan Tang
- Department of Endocrinology, The First People's Hospital of Yulin, Yulin, China
| | - Liheng Meng
- Department of Endocrinology, First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Ping Zhang
- Department of Endocrinology, The First People's Hospital of Yulin, Yulin, China
| | - Xinghuan Liang
- Department of Endocrinology, First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Chaozhi Dang
- Department of Endocrinology, The First People's Hospital of Yulin, Yulin, China
| | - Hui Liang
- Department of Endocrinology, The First People's Hospital of Yulin, Yulin, China
| | - Junfeng Wu
- Department of Endocrinology, The First People's Hospital of Yulin, Yulin, China
| | - Haiyun Lan
- Department of Endocrinology, The First People's Hospital of Yulin, Yulin, China
| | - Yingfen Qin
- Department of Endocrinology, First Affiliated Hospital of Guangxi Medical University, Nanning, China
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112
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Li M, Han X, Ji L. Clinical and Genetic Characteristics of ABCC8 Nonneonatal Diabetes Mellitus: A Systematic Review. J Diabetes Res 2021; 2021:9479268. [PMID: 34631896 PMCID: PMC8497126 DOI: 10.1155/2021/9479268] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 02/06/2023] Open
Abstract
OBJECTIVES Diabetes mellitus (DM) is a major chronic metabolic disease in the world, and the prevalence has been increasing rapidly in recent years. The channel of KATP plays an important role in the regulation of insulin secretion. The variants in ABCC8 gene encoding the SUR1 subunit of KATP could cause a variety of phenotypes, including neonatal diabetes mellitus (ABCC8-NDM) and ABCC8-induced nonneonatal diabetes mellitus (ABCC8-NNDM). Since the features of ABCC8-NNDM have not been elucidated, this study is aimed at concluding the genetic features and clinical characteristics. METHODS We comprehensively reviewed the literature associated with ABCC8-NNDM in the following databases: MEDLINE, PubMed, and Web of Science to investigate the features of ABCC8-NNDM. RESULTS Based on a comprehensive literature search, we found that 87 probands with ABCC8-NNDM carried 71 ABCC8 genetic variant alleles, 24% of whom carried inactivating variants, 24% carried activating variants, and the remaining 52% carried activating or inactivating variants. Nine of these variants were confirmed to be activating or inactivating through functional studies, while four variants (p.R370S, p.E1506K, p.R1418H, and p.R1420H) were confirmed to be inactivating. The phenotypes of ABCC8-NNDM were variable and could also present with early hyperinsulinemia followed by reduced insulin secretion, progressing to diabetes later. They had a relatively high risk of microvascular complications and low prevalence of nervous disease, which is different from ABCC8-NDM. CONCLUSIONS Genetic testing is essential for proper diagnosis and appropriate treatment for patients with ABCC8-NNDM. And further studies are required to determine the complex mechanism of the variants of ABCC8-NNDM.
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Affiliation(s)
- Meng Li
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Center, Beijing, China 100044
| | - Xueyao Han
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Center, Beijing, China 100044
| | - Linong Ji
- Department of Endocrinology and Metabolism, Peking University People's Hospital, Peking University Diabetes Center, Beijing, China 100044
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113
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Hussain MA, Laimon-Thomson E, Mustafa SM, Deck A, Song B. Detour Ahead: Incretin Hormone Signaling Alters Its Intracellular Path as β-Cell Failure Progresses During Diabetes. Front Endocrinol (Lausanne) 2021; 12:665345. [PMID: 33935974 PMCID: PMC8082395 DOI: 10.3389/fendo.2021.665345] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Accepted: 03/16/2021] [Indexed: 12/12/2022] Open
Affiliation(s)
- Mehboob A. Hussain
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, United States
- *Correspondence: Mehboob A. Hussain,
| | - Erinn Laimon-Thomson
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, United States
| | - Syed M. Mustafa
- College of Literature, Science and Arts, University of Michigan, Ann Arbor, MI, United States
| | - Alexander Deck
- College of Literature, Science and Arts, University of Michigan, Ann Arbor, MI, United States
| | - Banya Song
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI, United States
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Shah W, Khan R, Shah B, Khan A, Dil S, Liu W, Wen J, Jiang X. The Molecular Mechanism of Sex Hormones on Sertoli Cell Development and Proliferation. Front Endocrinol (Lausanne) 2021; 12:648141. [PMID: 34367061 PMCID: PMC8344352 DOI: 10.3389/fendo.2021.648141] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 05/17/2021] [Indexed: 12/30/2022] Open
Abstract
Sustaining and maintaining the intricate process of spermatogenesis is liable upon hormones and growth factors acting through endocrine and paracrine pathways. The Sertoli cells (SCs) are the major somatic cells present in the seminiferous tubules and are considered to be the main regulators of spermatogenesis. As each Sertoli cell supports a specific number of germ cells, thus, the final number of Sertoli cells determines the sperm production capacity. Similarly, sex hormones are also major regulators of spermatogenesis and they can determine the proliferation of Sertoli cells. In the present review, we have critically and comprehensively discussed the role of sex hormones and some other factors that are involved in Sertoli cell proliferation, differentiation and maturation. Furthermore, we have also presented a model of Sertoli cell development based upon the recent advancement in the field of reproduction. Hence, our review article provides a general overview regarding the sex hormonal pathways governing Sertoli cell proliferation and development.
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Affiliation(s)
| | - Ranjha Khan
- *Correspondence: Xiaohua Jiang, ; Ranjha Khan, ; Jie Wen,
| | | | | | | | | | - Jie Wen
- *Correspondence: Xiaohua Jiang, ; Ranjha Khan, ; Jie Wen,
| | - Xiaohua Jiang
- *Correspondence: Xiaohua Jiang, ; Ranjha Khan, ; Jie Wen,
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115
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Fei Y, Shi R, Song Z, Wu J. Metabolic Control of Epilepsy: A Promising Therapeutic Target for Epilepsy. Front Neurol 2020; 11:592514. [PMID: 33363507 PMCID: PMC7753014 DOI: 10.3389/fneur.2020.592514] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 11/20/2020] [Indexed: 12/16/2022] Open
Abstract
Epilepsy is a common neurological disease that is not always controlled, and the ketogenic diet shows good antiepileptic effects drug-resistant epilepsy or seizures caused by specific metabolic defects via regulating the metabolism. The brain is a vital organ with high metabolic demands, and epileptic foci tend to exhibit high metabolic characteristics. Accordingly, there has been growing interest in the relationship between brain metabolism and epilepsy in recent years. To date, several new antiepileptic therapies targeting metabolic pathways have been proposed (i.e., inhibiting glycolysis, targeting lactate dehydrogenase, and dietary therapy). Promising strategies to treat epilepsy via modulating the brain's metabolism could be expected, while a lack of thorough understanding of the role of brain metabolism in the control of epilepsy remains. Herein, this review aims to provide insight into the state of the art concerning the brain's metabolic patterns and their association with epilepsy. Regulation of neuronal excitation via metabolic pathways and antiepileptic therapies targeting metabolic pathways are emphasized, which could provide a better understanding of the role of metabolism in epilepsy and could reveal potential therapeutic targets.
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Affiliation(s)
- Yanqing Fei
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Ruting Shi
- Department of Rehabilitation, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Zhi Song
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Jinze Wu
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
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116
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Yasumatsu K, Ohkuri T, Yoshida R, Iwata S, Margolskee RF, Ninomiya Y. Sodium-glucose cotransporter 1 as a sugar taste sensor in mouse tongue. Acta Physiol (Oxf) 2020; 230:e13529. [PMID: 32599649 DOI: 10.1111/apha.13529] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 12/20/2022]
Abstract
AIM We investigated potential neuron types that code sugar information and how sodium-glucose cotransporters (SGLTs) and T1Rs are involved. METHODS Whole-nerve recordings in the chorda tympani (CT) and the glossopharyngeal (GL) nerves and single-fibre recordings in the CT were performed in T1R3-KO and wild-type (WT) mice. Behavioural response measurements were conducted in T1R3-KO mice using phlorizin (Phl), a competitive inhibitor of SGLTs. RESULTS Results indicated that significant enhancement occurred in responses to sucrose and glucose (Glc) by adding 10 mmol/L NaCl but not in responses to KCl, monopotassium glutamate, citric acid, quinine sulphate, SC45647(SC) or polycose in both CT and GL nerves. These enhancements were abolished by lingual application of Phl. In single-fibre recording, fibres showing maximal response to sucrose could be classified according to responses to SC and Glc with or without 10 mmol/L NaCl in the CT of WT mice, namely, Phl-insensitive type, Phl-sensitive Glc-type and Mixed (Glc and SC responding)-type fibres. In T1R3-KO mice, Phl-insensitive-type fibres disappeared. Results from behavioural experiments showed that the number of licks and amount of intake for Glc with or without 10 mmol/L NaCl were significantly suppressed by Phl. CONCLUSION We found evidence for the contribution of SGLTs in sugar sensing in taste cells of mouse tongue. Moreover, we found T1R-dependent (Phl-insensitive) type, Glc-type and Mixed (SGLTs and T1Rs)-type fibres. SGLT1 may be involved in the latter two types and may play important roles in the glucose-specific cephalic phase of digestion and palatable food intake.
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Affiliation(s)
- Keiko Yasumatsu
- Tokyo Dental Junior College Chiyoda‐ku Tokyo Japan
- Division of Sensory Physiology and Medical Application Sensing, Research and Development Centre for Five‐Sense Devices Kyushu University Fukuoka Japan
| | - Tadahiro Ohkuri
- Section of Oral Neuroscience Graduate School of Dental Sciences Kyushu University Fukuoka Japan
| | - Ryusuke Yoshida
- Section of Oral Neuroscience Graduate School of Dental Sciences Kyushu University Fukuoka Japan
- Department of Oral Physiology Graduate School of Medicine, Dentistry and Pharmaceutical Sciences Okayama University Okayama Japan
| | - Shusuke Iwata
- Division of Sensory Physiology and Medical Application Sensing, Research and Development Centre for Five‐Sense Devices Kyushu University Fukuoka Japan
- Section of Oral Neuroscience Graduate School of Dental Sciences Kyushu University Fukuoka Japan
| | | | - Yuzo Ninomiya
- Division of Sensory Physiology and Medical Application Sensing, Research and Development Centre for Five‐Sense Devices Kyushu University Fukuoka Japan
- Monell Chemical Senses Centre Philadelphia PA USA
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117
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Song L, Barrett DG, Cox KL, Efanov AM, Syed SK, Tomandl D, Willard FS. A High-Throughput Assay for the Pancreatic Islet Beta-Cell Potassium Channel: Use in the Pharmacological Characterization of Insulin Secretagogues Identified from Phenotypic Screening. Assay Drug Dev Technol 2020; 19:27-37. [PMID: 33164547 DOI: 10.1089/adt.2020.1011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Phenotypic screening is a neoclassical approach for drug discovery. We conducted phenotypic screening for insulin secretion enhancing agents using INS-1E insulinoma cells as a model system for pancreatic beta-cells. A principal regulator of insulin secretion in beta-cells is the metabolically regulated potassium channel Kir6.2/SUR1 complex. To characterize hit compounds, we developed an assay to quantify endogenous potassium channel activity in INS-1E cells. We quantified ligand-regulated potassium channel activity in INS-1E cells using fluorescence imaging and thallium flux. Potassium channel activity was metabolically regulated and coupled to insulin secretion. The pharmacology of channel opening agents (diazoxide) and closing agents (sulfonylureas) was used to validate the applicability of the assay. A precise high-throughput assay was enabled, and phenotypic screening hits were triaged to enable a higher likelihood of discovering chemical matter with novel and useful mechanisms of action.
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Affiliation(s)
- Luyan Song
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - David G Barrett
- Discovery Chemistry, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Karen L Cox
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Alexander M Efanov
- Diabetes and Complications Therapeutic Area, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Samreen K Syed
- Diabetes and Complications Therapeutic Area, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Dirk Tomandl
- Discovery Informatics, Lilly Research Laboratories, Indianapolis, Indiana, USA
| | - Francis S Willard
- Quantitative Biology, Lilly Research Laboratories, Indianapolis, Indiana, USA
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118
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Haigh JL, New LE, Filippi BM. Mitochondrial Dynamics in the Brain Are Associated With Feeding, Glucose Homeostasis, and Whole-Body Metabolism. Front Endocrinol (Lausanne) 2020; 11:580879. [PMID: 33240218 PMCID: PMC7680879 DOI: 10.3389/fendo.2020.580879] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/05/2020] [Indexed: 12/13/2022] Open
Abstract
The brain is responsible for maintaining whole-body energy homeostasis by changing energy input and availability. The hypothalamus and dorsal vagal complex (DVC) are the primary sites of metabolic control, able to sense both hormones and nutrients and adapt metabolism accordingly. The mitochondria respond to the level of nutrient availability by fusion or fission to maintain energy homeostasis; however, these processes can be disrupted by metabolic diseases including obesity and type II diabetes (T2D). Mitochondrial dynamics are crucial in the development and maintenance of obesity and T2D, playing a role in the control of glucose homeostasis and whole-body metabolism across neurons and glia in the hypothalamus and DVC.
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Affiliation(s)
| | | | - Beatrice M. Filippi
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
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119
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McClenaghan C, Huang Y, Yan Z, Harter TM, Halabi CM, Chalk R, Kovacs A, van Haaften G, Remedi MS, Nichols CG. Glibenclamide reverses cardiovascular abnormalities of Cantu syndrome driven by KATP channel overactivity. J Clin Invest 2020; 130:1116-1121. [PMID: 31821173 DOI: 10.1172/jci130571] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Accepted: 12/05/2019] [Indexed: 12/12/2022] Open
Abstract
Cantu syndrome (CS) is a complex disorder caused by gain-of-function (GoF) mutations in ABCC9 and KCNJ8, which encode the SUR2 and Kir6.1 subunits, respectively, of vascular smooth muscle (VSM) KATP channels. CS includes dilated vasculature, marked cardiac hypertrophy, and other cardiovascular abnormalities. There is currently no targeted therapy, and it is unknown whether cardiovascular features can be reversed once manifest. Using combined transgenic and pharmacological approaches in a knockin mouse model of CS, we have shown that reversal of vascular and cardiac phenotypes can be achieved by genetic downregulation of KATP channel activity specifically in VSM, and by chronic administration of the clinically used KATP channel inhibitor, glibenclamide. These findings demonstrate that VSM KATP channel GoF underlies CS cardiac enlargement and that CS-associated abnormalities are reversible, and provide evidence of in vivo efficacy of glibenclamide as a therapeutic agent in CS.
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Affiliation(s)
- Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases.,Department of Cell Biology.,Department of Physiology
| | - Yan Huang
- Center for the Investigation of Membrane Excitability Diseases.,Department of Cell Biology.,Department of Physiology
| | - Zihan Yan
- Center for the Investigation of Membrane Excitability Diseases.,Division of Endocrinology, Department of Medicine, and
| | - Theresa M Harter
- Center for the Investigation of Membrane Excitability Diseases.,Department of Cell Biology.,Department of Physiology
| | - Carmen M Halabi
- Center for the Investigation of Membrane Excitability Diseases.,Division of Nephrology, Department of Pediatrics, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Rod Chalk
- Structural Genomics Consortium, University of Oxford, Oxford, United Kingdom
| | - Attila Kovacs
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri, USA
| | - Gijs van Haaften
- Center for Molecular Medicine, Department of Genetics, University Medical Center Utrecht, Utrecht, Netherlands
| | - Maria S Remedi
- Center for the Investigation of Membrane Excitability Diseases.,Division of Endocrinology, Department of Medicine, and
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases.,Department of Cell Biology.,Department of Physiology
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120
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Lewandowski SL, Cardone RL, Foster HR, Ho T, Potapenko E, Poudel C, VanDeusen HR, Sdao SM, Alves TC, Zhao X, Capozzi ME, de Souza AH, Jahan I, Thomas CJ, Nunemaker CS, Davis DB, Campbell JE, Kibbey RG, Merrins MJ. Pyruvate Kinase Controls Signal Strength in the Insulin Secretory Pathway. Cell Metab 2020; 32:736-750.e5. [PMID: 33147484 PMCID: PMC7685238 DOI: 10.1016/j.cmet.2020.10.007] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 06/30/2020] [Accepted: 10/09/2020] [Indexed: 12/14/2022]
Abstract
Pancreatic β cells couple nutrient metabolism with appropriate insulin secretion. Here, we show that pyruvate kinase (PK), which converts ADP and phosphoenolpyruvate (PEP) into ATP and pyruvate, underlies β cell sensing of both glycolytic and mitochondrial fuels. Plasma membrane-localized PK is sufficient to close KATP channels and initiate calcium influx. Small-molecule PK activators increase the frequency of ATP/ADP and calcium oscillations and potently amplify insulin secretion. PK restricts respiration by cyclically depriving mitochondria of ADP, which accelerates PEP cycling until membrane depolarization restores ADP and oxidative phosphorylation. Our findings support a compartmentalized model of β cell metabolism in which PK locally generates the ATP/ADP required for insulin secretion. Oscillatory PK activity allows mitochondria to perform synthetic and oxidative functions without any net impact on glucose oxidation. These findings suggest a potential therapeutic route for diabetes based on PK activation that would not be predicted by the current consensus single-state model of β cell function.
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Affiliation(s)
- Sophie L Lewandowski
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Rebecca L Cardone
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Hannah R Foster
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Thuong Ho
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Evgeniy Potapenko
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Chetan Poudel
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Halena R VanDeusen
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sophia M Sdao
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Tiago C Alves
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Xiaojian Zhao
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC 27701, USA
| | - Arnaldo H de Souza
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Ishrat Jahan
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Craig J Thomas
- National Center for Advancing Translational Sciences, Rockville, MD 20850, USA
| | - Craig S Nunemaker
- Department of Biomedical Sciences, Ohio University, Athens, OH 45701, USA
| | - Dawn Belt Davis
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA
| | | | - Richard G Kibbey
- Department of Internal Medicine, Yale University, New Haven, CT 06520, USA; Department of Cellular & Molecular Physiology, Yale University, New Haven, CT 06520, USA.
| | - Matthew J Merrins
- Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, University of Wisconsin-Madison, Madison, WI 53705, USA; William S. Middleton Memorial Veterans Hospital, Madison, WI 53705, USA.
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121
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Perry RJ, Saunders CJ, Nelson JM, Rizzo MJ, Braco JT, Johnson EC. Regulation of Metabolism by an Ensemble of Different Ion Channel Types: Excitation-Secretion Coupling Mechanisms of Adipokinetic Hormone Producing Cells in Drosophila. Front Physiol 2020; 11:580618. [PMID: 33192586 PMCID: PMC7658370 DOI: 10.3389/fphys.2020.580618] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/07/2020] [Indexed: 12/11/2022] Open
Abstract
Adipokinetic Hormone (AKH) is the primary insect hormone that mobilizes stored energy and is functional equivalent to mammalian glucagon. While most studies have focused on exploring the functional roles of AKH, relatively little is known about how AKH secretion is regulated. We assessed the AKH cell transcriptome and mined the data set for specific insight into the identities of different ion channels expressed in this cell lineage. We found reliable expression of multiple ion channel genes with multiple members for each ionic species. Specifically, we found significant signals for 39 of the either known or suspected ion channel genes within the Drosophila genome. We next performed a targeted RNAi screen aimed to identify the functional contribution of these different ion channels that may participate in excitation-secretion coupling in AKH producing cells (APCs). We assessed starvation survival, because changes in AKH signaling have previously been shown to impact starvation sensitivity. Genetic knockdown of three genes (Ca-Beta, Sur, and sei), in AKH producing cells caused highly significant changes (P < 0.001) in both male and female lifespan, and knockdown of six other genes (Shaw, cac, Ih, NaCP60E, stj, and TASK6) caused significant changes (P < 0.05) in only female lifespan. Specifically, the genetic knockdown of Ca-Beta and Sur led to increases in starvation lifespan, whereas the knockdown of sei decreased starvation survivorship. Focusing on these three strongest candidates from the behavioral screen, we assessed other AKH-dependent phenotypes. The AKH hormone is required for starvation-induced hyperactivity, and we found that these three ion channel gene knockdowns changed activity profiles and further suggest a modulatory role of these channels in AKH release. We eliminated the possibility that these genetic elements caused AKH cell lethality, and using independent methods, we verified expression of these genes in AKH cells. Collectively, these results suggest a model of AKH-cell excitability and establish an experimental framework for evaluating intrinsic mechanisms of AKH release.
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Affiliation(s)
- Rebecca J Perry
- Department of Biology, Wake Forest University, Winston-Salem, NC, United States
| | - Cecil J Saunders
- Department of Biology, Wake Forest University, Winston-Salem, NC, United States
| | - Jonathan M Nelson
- Department of Biology, Wake Forest University, Winston-Salem, NC, United States
| | - Michael J Rizzo
- Department of Biology, Wake Forest University, Winston-Salem, NC, United States
| | - Jason T Braco
- Department of Biology, Wake Forest University, Winston-Salem, NC, United States
| | - Erik C Johnson
- Department of Biology, Wake Forest University, Winston-Salem, NC, United States
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122
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Varró A, Tomek J, Nagy N, Virág L, Passini E, Rodriguez B, Baczkó I. Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior. Physiol Rev 2020; 101:1083-1176. [PMID: 33118864 DOI: 10.1152/physrev.00024.2019] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.
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Affiliation(s)
- András Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - Jakub Tomek
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Norbert Nagy
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary.,MTA-SZTE Cardiovascular Pharmacology Research Group, Hungarian Academy of Sciences, Szeged, Hungary
| | - László Virág
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Elisa Passini
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Blanca Rodriguez
- Department of Computer Science, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - István Baczkó
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
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Johnson A, Grove RA, Madhavan D, Boone CHT, Braga C, Kyllo H, Samson K, Simeone K, Simeone T, Helikar T, Hanson CK, Adamec J. Changes in lipid profiles of epileptic mouse model. Metabolomics 2020; 16:106. [PMID: 33021695 PMCID: PMC10614666 DOI: 10.1007/s11306-020-01729-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 09/23/2020] [Indexed: 12/21/2022]
Abstract
INTRODUCTION Approximately 1% of the world's population is impacted by epilepsy, a chronic neurological disorder characterized by seizures. One-third of epileptic patients are resistant to AEDs, or have medically refractory epilepsy (MRE). One non-invasive treatment that exists for MRE includes the ketogenic diet, a high-fat, low-carbohydrate diet. Despite the KD's success in seizure attenuation, it has a few risks and its mechanisms remain poorly understood. The KD has been shown to improve metabolism and mitochondrial function in epileptic phenotypes. Potassium channels have implications in epileptic conditions as they have dual roles as metabolic sensors and control neuronal excitation. OBJECTIVES The goal of this study was to explore changes in the lipidome in hippocampal and cortical tissue from Kv1.1-KO model of epilepsy. METHODS FT-ICR/MS analysis was utilized to examine nonpolar metabolome of cortical and hippocampal tissue isolated from a Kv1.1 channel knockout mouse model of epilepsy (n = 5) and wild-type mice (n = 5). RESULTS Distinct metabolic profiles were observed, significant (p < 0.05) features in hippocampus often being upregulated (FC ≥ 2) and the cortex being downregulated (FC ≤ 0.5). Pathway enrichment analysis shows lipid biosynthesis was affected. Partition ratio analysis revealed that the ratio of most metabolites tended to be increased in Kv1.1-/-. Metabolites in hippocampal tissue were commonly upregulated, suggesting seizure initiation in the hippocampus. Aberrant mitochondrial function is implicated by the upregulation of cardiolipin, a common component in the mitochondrial membrane. CONCLUSION Generally, our study finds that the lipidome is changed in the hippocampus and cortex in response to Kv1.1-KO indicating changes in membrane structural integrity and synaptic transmission.
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Affiliation(s)
- Alicia Johnson
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Ryan A Grove
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Deepak Madhavan
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Cory H T Boone
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Camila Braga
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Hannah Kyllo
- Department of Neurological Sciences, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Kaeli Samson
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Kristina Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Timothy Simeone
- Department of Pharmacology, Creighton University School of Medicine, Omaha, NE, 68178, USA
| | - Tomas Helikar
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA
| | - Corrine K Hanson
- College of Allied Health Professions, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Jiri Adamec
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, 68588, USA.
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Mouithys-Mickalad A, Ceusters J, Charif M, El Moualij B, Schoumacher M, Plyte S, Franck T, Bettendorff L, Pirotte B, Serteyn D, de Tullio P. Modulation of mitochondrial respiration rate and calcium-induced swelling by new cromakalim analogues. Chem Biol Interact 2020; 331:109272. [PMID: 33010220 DOI: 10.1016/j.cbi.2020.109272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Revised: 09/07/2020] [Accepted: 09/28/2020] [Indexed: 10/23/2022]
Abstract
A cellular model of cardiomyocytes (H9c2 cell line) and mitochondria isolated from mouse liver were used to understand the drug action of BPDZ490 and BPDZ711, two benzopyran analogues of the reference potassium channel opener cromakalim, on mitochondrial respiratory parameters and swelling, by comparing their effects with those of the parent compound cromakalim. For these three compounds, the oxygen consumption rate (OCR) was determined by high-resolution respirometry (HRR) and their impact on adenosine triphosphate (ATP) production and calcium-induced mitochondrial swelling was investigated. Cromakalim did not modify neither the OCR of H9c2 cells and the ATP production nor the Ca-induced swelling. By contrast, the cromakalim analogue BPDZ490 (1) induced a strong increase of OCR, while the other benzopyran analogue BPDZ711 (2) caused a marked slowdown. For both compounds, 1 displayed a biphasic behavior while 2 still showed an inhibitory effect. Both compounds 1 and 2 were also found to decrease the ATP synthesis, with pronounced effect for 2, while cromakalim remained without effect. Overall, these results indicate that cromakalim, as parent molecule, does not induce per se any direct effect on mitochondrial respiratory function neither on whole cells nor on isolated mitochondria whereas both benzopyran analogues 1 and 2 display totally opposite behavior profiles, suggesting that compound 1, by increasing the maximal respiration capacity, might behave as a mild uncoupling agent and compound 2 is taken as an inhibitor of the mitochondrial electron-transfer chain.
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Affiliation(s)
- Ange Mouithys-Mickalad
- Center for Oxygen, Research & Development (CORD) & Center for Interdisciplinary Research on Medicines (CIRM), Institute of Chemistry, B6a, ULiège, Allée du six Août, 11, B-4000, Liège, Belgium.
| | - Justine Ceusters
- Center for Oxygen, Research & Development (CORD) & Center for Interdisciplinary Research on Medicines (CIRM), Institute of Chemistry, B6a, ULiège, Allée du six Août, 11, B-4000, Liège, Belgium
| | - Mounia Charif
- Centre de Recherche sur les Protéines Prions (CRPP), ULiège, Quartier Hôpital, 15, Avenue Hippocrate, B-4000, Liège, Belgium
| | - Benaïssa El Moualij
- Centre de Recherche sur les Protéines Prions (CRPP), ULiège, Quartier Hôpital, 15, Avenue Hippocrate, B-4000, Liège, Belgium
| | - Mathieu Schoumacher
- Department of Medicinal Chemistry, Center for Interdisciplinary Research on Medicines (CIRM), ULiège, Quartier Hôpital, 15, Avenue de l'Hospital, B-4000, Liège, Belgium
| | - Simon Plyte
- Merus, Closing in on Cancer, Immuno-Oncology, Yalelaan 62, 3584 CM, Utrecht, the Netherlands
| | - Thierry Franck
- Center for Oxygen, Research & Development (CORD) & Center for Interdisciplinary Research on Medicines (CIRM), Institute of Chemistry, B6a, ULiège, Allée du six Août, 11, B-4000, Liège, Belgium; Department of Clinical Sciences, Faculty of Veterinary Medicine, Quartier Vallée 2, 5A-5D, Avenue de Cureghem, ULiège, B-4000, Liège, Belgium
| | - Lucien Bettendorff
- Laboratory of Neurophysiology, GIGA-neurosciences, ULiège, Quartier Hôpital, 15, Avenue Hippocrate, B-4000, Liège, Belgium
| | - Bernard Pirotte
- Center for Oxygen, Research & Development (CORD) & Center for Interdisciplinary Research on Medicines (CIRM), Institute of Chemistry, B6a, ULiège, Allée du six Août, 11, B-4000, Liège, Belgium; Department of Medicinal Chemistry, Center for Interdisciplinary Research on Medicines (CIRM), ULiège, Quartier Hôpital, 15, Avenue de l'Hospital, B-4000, Liège, Belgium
| | - Didier Serteyn
- Center for Oxygen, Research & Development (CORD) & Center for Interdisciplinary Research on Medicines (CIRM), Institute of Chemistry, B6a, ULiège, Allée du six Août, 11, B-4000, Liège, Belgium
| | - Pascal de Tullio
- Center for Oxygen, Research & Development (CORD) & Center for Interdisciplinary Research on Medicines (CIRM), Institute of Chemistry, B6a, ULiège, Allée du six Août, 11, B-4000, Liège, Belgium; Department of Medicinal Chemistry, Center for Interdisciplinary Research on Medicines (CIRM), ULiège, Quartier Hôpital, 15, Avenue de l'Hospital, B-4000, Liège, Belgium
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Qiu Y, Yang Y, Wei Y, Liu X, Feng Z, Zeng X, Chen Y, Liu Y, Zhao Y, Chen L, Luo L, Ding Q. Glyburide Regulates UCP1 Expression in Adipocytes Independent of K ATP Channel Blockade. iScience 2020; 23:101446. [PMID: 32829287 PMCID: PMC7452185 DOI: 10.1016/j.isci.2020.101446] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/08/2020] [Accepted: 08/06/2020] [Indexed: 12/12/2022] Open
Abstract
Identification of safe and effective compounds to increase or activate UCP1 expression in brown or white adipocytes remains a potent therapeutic strategy to combat obesity. Here we reported that, glyburide, one of the FDA-approved drugs currently used to treat type 2 diabetes, can significantly enhance UCP1 expression in both brown and white adipocytes. Glyburide-fed mice exhibited a clear resistance to high-fat diet-induced obesity, reduced blood triglyceride level, and increased UCP1 expression in brown adipose tissue. Moreover, in situ injection of glyburide to inguinal white adipose tissue remarkably enhanced UCP1 expression and increased thermogenesis. Further mechanistic studies indicated that the glyburide effect in UCP1 expression in adipocytes was KATP channel independent but may involve the regulation of the Ca2+-Calcineurin-NFAT signal pathway. Overall, our findings revealed the significant effects of glyburide in regulating UCP1 expression and thermogenesis in adipocytes, which can be potentially repurposed to treat obesity.
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Affiliation(s)
- Yan Qiu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Yuanyuan Yang
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Yuda Wei
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Xiaojian Liu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Zhuanghui Feng
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Xuwen Zeng
- The Affiliated Stomatology Hospital of Tongji University, 399 Yanchang Road, Shanghai 200072, P. R. China
| | - Yanhao Chen
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Yan Liu
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Yongxu Zhao
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Lanlan Chen
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
| | - Lijun Luo
- The Affiliated Stomatology Hospital of Tongji University, 399 Yanchang Road, Shanghai 200072, P. R. China
| | - Qiurong Ding
- CAS Key Laboratory of Nutrition, Metabolism and Food Safety, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing 100101, P. R. China
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Le Ribeuz H, Capuano V, Girerd B, Humbert M, Montani D, Antigny F. Implication of Potassium Channels in the Pathophysiology of Pulmonary Arterial Hypertension. Biomolecules 2020; 10:biom10091261. [PMID: 32882918 PMCID: PMC7564204 DOI: 10.3390/biom10091261] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/24/2020] [Accepted: 08/27/2020] [Indexed: 02/06/2023] Open
Abstract
Pulmonary arterial hypertension (PAH) is a rare and severe cardiopulmonary disease without curative treatments. PAH is a multifactorial disease that involves genetic predisposition, epigenetic factors, and environmental factors (drugs, toxins, viruses, hypoxia, and inflammation), which contribute to the initiation or development of irreversible remodeling of the pulmonary vessels. The recent identification of loss-of-function mutations in KCNK3 (KCNK3 or TASK-1) and ABCC8 (SUR1), or gain-of-function mutations in ABCC9 (SUR2), as well as polymorphisms in KCNA5 (Kv1.5), which encode two potassium (K+) channels and two K+ channel regulatory subunits, has revived the interest of ion channels in PAH. This review focuses on KCNK3, SUR1, SUR2, and Kv1.5 channels in pulmonary vasculature and discusses their pathophysiological contribution to and therapeutic potential in PAH.
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Affiliation(s)
- Hélène Le Ribeuz
- Faculté de Médecine, Université Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (H.L.R.); (V.C.); (B.G.); (M.H.); (D.M.)
- INSERM UMR_S 999, Hypertension pulmonaire, Physiopathologie et Innovation Thérapeutique, Hôpital Marie Lannelongue, 92350 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, 94270 Le Kremlin-Bicêtre, France
| | - Véronique Capuano
- Faculté de Médecine, Université Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (H.L.R.); (V.C.); (B.G.); (M.H.); (D.M.)
- INSERM UMR_S 999, Hypertension pulmonaire, Physiopathologie et Innovation Thérapeutique, Hôpital Marie Lannelongue, 92350 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, 94270 Le Kremlin-Bicêtre, France
| | - Barbara Girerd
- Faculté de Médecine, Université Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (H.L.R.); (V.C.); (B.G.); (M.H.); (D.M.)
- INSERM UMR_S 999, Hypertension pulmonaire, Physiopathologie et Innovation Thérapeutique, Hôpital Marie Lannelongue, 92350 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, 94270 Le Kremlin-Bicêtre, France
| | - Marc Humbert
- Faculté de Médecine, Université Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (H.L.R.); (V.C.); (B.G.); (M.H.); (D.M.)
- INSERM UMR_S 999, Hypertension pulmonaire, Physiopathologie et Innovation Thérapeutique, Hôpital Marie Lannelongue, 92350 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, 94270 Le Kremlin-Bicêtre, France
| | - David Montani
- Faculté de Médecine, Université Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (H.L.R.); (V.C.); (B.G.); (M.H.); (D.M.)
- INSERM UMR_S 999, Hypertension pulmonaire, Physiopathologie et Innovation Thérapeutique, Hôpital Marie Lannelongue, 92350 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, 94270 Le Kremlin-Bicêtre, France
| | - Fabrice Antigny
- Faculté de Médecine, Université Paris-Saclay, 94270 Le Kremlin-Bicêtre, France; (H.L.R.); (V.C.); (B.G.); (M.H.); (D.M.)
- INSERM UMR_S 999, Hypertension pulmonaire, Physiopathologie et Innovation Thérapeutique, Hôpital Marie Lannelongue, 92350 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, 94270 Le Kremlin-Bicêtre, France
- Correspondence: or ; Tel.: +33-1-40-94-22-99
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McIver EL, Atherton JF, Chu HY, Cosgrove KE, Kondapalli J, Wokosin D, Surmeier DJ, Bevan MD. Maladaptive Downregulation of Autonomous Subthalamic Nucleus Activity following the Loss of Midbrain Dopamine Neurons. Cell Rep 2020; 28:992-1002.e4. [PMID: 31340159 PMCID: PMC6699776 DOI: 10.1016/j.celrep.2019.06.076] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 05/22/2019] [Accepted: 06/19/2019] [Indexed: 01/13/2023] Open
Abstract
Abnormal subthalamic nucleus (STN) activity is linked to impaired movement in Parkinson’s disease (PD). The autonomous firing of STN neurons, which contributes to their tonic excitation of the extrastriatal basal ganglia and shapes their integration of synaptic input, is downregulated in PD models. Using electrophysiological, chemogenetic, genetic, and optical approaches, we find that chemogenetic activation of indirect pathway striatopallidal neurons downregulates intrinsic STN activity in normal mice but this effect is occluded in Parkinsonian mice. Loss of autonomous spiking in PD mice is prevented by STN N-methyl-D-aspartate receptor (NMDAR) knockdown and reversed by reactive oxygen species breakdown or KATP channel inhibition. Chemogenetic activation of hM3D(Gq) in STN neurons in Parkinsonian mice rescues their intrinsic activity, modifies their synaptic integration, and ameliorates motor dysfunction. Together these data argue that in PD mice increased indirect pathway activity leads to disinhibition of the STN, which triggers maladaptive NMDAR-dependent downregulation of autonomous firing. McIver et al. describe the cellular and circuit mechanisms responsible for the loss of autonomous subthalamic nucleus (STN) spiking in dopamine-depleted mice and demonstrate that chemogenetic rescue of intrinsic STN activity reduces Parkinsonian motor dysfunction.
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Affiliation(s)
- Eileen L McIver
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - Jeremy F Atherton
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - Hong-Yuan Chu
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - Kathleen E Cosgrove
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - Jyothisri Kondapalli
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - David Wokosin
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - D James Surmeier
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA
| | - Mark D Bevan
- Department of Physiology, Feinberg School of Medicine, Northwestern University, 303 E. Chicago Ave., Chicago, IL 60611, USA.
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Zhang Q, Dou H, Rorsman P. 'Resistance is futile?' - paradoxical inhibitory effects of K ATP channel closure in glucagon-secreting α-cells. J Physiol 2020; 598:4765-4780. [PMID: 32716554 PMCID: PMC7689873 DOI: 10.1113/jp279775] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 07/24/2020] [Indexed: 12/12/2022] Open
Abstract
By secreting insulin and glucagon, the β- and α-cells of the pancreatic islets play a central role in the regulation of systemic metabolism. Both cells are equipped with ATP-regulated potassium (KATP ) channels that are regulated by the intracellular ATP/ADP ratio. In β-cells, KATP channels are active at low (non-insulin-releasing) glucose concentrations. An increase in glucose leads to KATP channel closure, membrane depolarization and electrical activity that culminates in elevation of [Ca2+ ]i and initiation of exocytosis of the insulin-containing secretory granules. The α-cells are also equipped with KATP channels but they are under strong tonic inhibition at low glucose, explaining why α-cells are electrically active under hypoglycaemic conditions and generate large Na+ - and Ca2+ -dependent action potentials. Closure of residual KATP channel activity leads to membrane depolarization and an increase in action potential firing but this stimulation of electrical activity is associated with inhibition rather than acceleration of glucagon secretion. This paradox arises because membrane depolarization reduces the amplitude of the action potentials by voltage-dependent inactivation of the Na+ channels involved in action potential generation. Exocytosis in α-cells is tightly linked to the opening of voltage-gated P/Q-type Ca2+ channels, the activation of which is steeply voltage-dependent. Accordingly, the inhibitory effect of the reduced action potential amplitude exceeds the stimulatory effect resulting from the increased action potential frequency. These observations highlight a previously unrecognised role of the action potential amplitude as a key regulator of pancreatic islet hormone secretion.
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Affiliation(s)
- Quan Zhang
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, OX3 7LE, UK
| | - Haiqiang Dou
- Metabolic Physiology Unit, Institute of Neuroscience and Physiology, University of Göteborg, PO Box 430, Göteborg, SE-405 30, Sweden
| | - Patrik Rorsman
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Churchill Hospital, Oxford, OX3 7LE, UK.,Metabolic Physiology Unit, Institute of Neuroscience and Physiology, University of Göteborg, PO Box 430, Göteborg, SE-405 30, Sweden
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Direct and indirect cholesterol effects on membrane proteins with special focus on potassium channels. Biochim Biophys Acta Mol Cell Biol Lipids 2020; 1865:158706. [DOI: 10.1016/j.bbalip.2020.158706] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 03/19/2020] [Accepted: 03/30/2020] [Indexed: 12/16/2022]
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Kuo YY, Lin JK, Lin YT, Chen JC, Kuo YM, Chen PS, Wu SN, Chen PC. Glibenclamide restores dopaminergic reward circuitry in obese mice through interscauplar brown adipose tissue. Psychoneuroendocrinology 2020; 118:104712. [PMID: 32479969 DOI: 10.1016/j.psyneuen.2020.104712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/29/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023]
Abstract
BACKGROUND Obesity, a critical feature in metabolic disorders, is associated with medical depression. Recent evidence reveals that brown adipose tissue (BAT) activity may contribute to mood disorders, Adenosine triphosphate (ATP)-sensitive K+ (KATP) channels regulate BAT sympathetic nerve activity. However, the mechanism through which BAT activity affects mood control remains unknown. We hypothesized the BAT is involved in depressive-like symptoms regulation by trafficking KATP channels. METHODS Eight-week-old male B6 mice fed with a high-fat diet (HFD) for 12 weeks exhibited characteristics of metabolic disorders, including hyperglycemia, hyperinsulinemia, and hyperlipidemia, as well as depressive symptoms. In this study, we surgically removed interscapular BAT in mice, and these mice exhibited immobility in the forced swim test and less preference for sugar water compared with other mice. To delineate the role of KATP channels in BAT activity regulation, we implanted a miniosmotic pump containing glibenclamide (GB), a KATP channel blocker, into the interscapular BAT of HFD-fed mice. RESULTS GB infusion improved glucose homeostasis, insulin sensitivity, and depressive-like symptoms. KATP channel expression was lower in HFD-fed mice than in chow-fed mice. Notably, GB infusion in HFD-fed mice restored KATP channel expression. CONCLUSION KATP channels are functionally expressed in BAT, and inhibiting BAT-KATP channels improves metabolic syndromes and reduces depressive symptoms through beta-3-adrenergic receptor-mediated protein kinase A signaling.
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Affiliation(s)
- Yi-Ying Kuo
- Department of Physiology, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | | | - Ya-Tin Lin
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan
| | - Jin-Chung Chen
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan
| | - Yu-Ming Kuo
- Department of Cell Biology and Anatomy, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Po-See Chen
- Department of Psychiatry, National Cheng Kung University Hospital, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Sheng-Nan Wu
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan
| | - Pei-Chun Chen
- Department of Physiology and Pharmacology, Graduate Institute of Biomedical Sciences, Chang-Gung University, Taiwan; Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, 701, Taiwan.
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131
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Bakhtiyari A, Haghani K, Bakhtiyari S, Zaimy MA, Noori-Zadeh A, Gheysarzadeh A, Darabi S, Seidkhani-Nahal A, Amraei M, Alipourfard I. Association between ABCC8 Ala1369Ser Polymorphism (rs757110 T/G) and Type 2 Diabetes Risk in an Iranian Population: A Case-Control Study. Endocr Metab Immune Disord Drug Targets 2020; 21:441-447. [PMID: 32660410 DOI: 10.2174/1871530320666200713091827] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Glucose metabolism increases ATP/ADP ratio within the β-cells and causes ATP-sensitive K+ (KATP) channel closure and consequently insulin secretion. The enhanced activity of the channel may be a mechanism contributing to the reduced first-phase of insulin secretion observed in T2DM. There is no study to date in the Kurdish ethnic group regarding the relationship between SNP Ala1369Ser (rs757110 T/G) of SUR1 gene and T2DM, and additionally, the results of this association in other populations are inconsistent. Therefore, our aim in this study was to explore the possible association between SNP Ala1369Ser and type 2 diabetes in an Iranian Kurdish ethnic group. METHODS In this study, we checked out the frequency of alleles and genotypes of SNP Ala1369Ser in T2DM individuals (207 patients; men/women: 106/101) and non-T2DM subjects (201 controls; men/women: 97/104), and their effects on anthropometric, clinical, and biochemical parameters. Genomic DNA was extracted from the leukocytes of blood specimens using a standard method. We amplified the ABCC8 rs757110 polymorphic site (T/G) using a polymerase chain reaction (PCR) method and a designed primer pair. To perform the PCR-RFLP method, the amplicons were subjected to restriction enzymes and the resulting fragments separated by gel electrophoresis. RESULTS The frequency of the G-allele of Ala1369Ser polymorphism was significantly (0.01) higher in the case group than the control group (19% vs. 9%, respectively). In the dominant model (TT vs. TG+GG), there was a significant relationship between this SNP and an increased risk of T2DM (P = 0.00). T2DM patients with TG+GG genotypes had significantly higher fasting plasma insulin and HOMA-IR than those who had the TT genotype (P = 0.02 and 0.01, respectively). CONCLUSION Our study is the first study to investigate the association between Ala1369Ser ABCC8 genetic variation and T2DM in the Kurdish population of western Iran. The obtained results clearly show that Ala1369Ser polymorphism of ABCC8 is associated with an increased risk of T2DM in this population.
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Affiliation(s)
- Amin Bakhtiyari
- Department of Genetics, Biology Research Center, Zanjan Branch, Islamic Azad University, Zanjan, Iran.,Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Karimeh Haghani
- Department of Clinical Biochemistry, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Salar Bakhtiyari
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.,Department of Clinical Biochemistry, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Mohammad A Zaimy
- Department of Medical Genetics, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Ali Noori-Zadeh
- Department of Clinical Biochemistry, Faculty of Allied Medical Sciences, Ilam University of Medical Sciences, Ilam, Iran
| | - Ali Gheysarzadeh
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.,Department of Biology, Faculty of Science, Ilam University, Ilam, Iran
| | - Shahram Darabi
- Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Ali Seidkhani-Nahal
- Department of Clinical Biochemistry, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Mansour Amraei
- Department of Physiology, Faculty of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Iraj Alipourfard
- School of Pharmacy, Faculty of Sciences, University of Rome Tor Vergata, Rome, Italy
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132
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Walczewska-Szewc K, Nowak W. Structural Determinants of Insulin Release: Disordered N-Terminal Tail of Kir6.2 Affects Potassium Channel Dynamics through Interactions with Sulfonylurea Binding Region in a SUR1 Partner. J Phys Chem B 2020; 124:6198-6211. [PMID: 32598150 PMCID: PMC7467719 DOI: 10.1021/acs.jpcb.0c02720] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
![]()
Inward rectifying
potassium ion channels (KATP), sensitive to the
ATP/ADP concentration ratio, play an important, control role in pancreatic
β cells. The channels close upon the increase of this ratio,
which, in turn, triggers insulin release to blood. Numerous mutations
in KATP lead to severe and widespread medical conditions such as diabetes.
The KATP system consists of a pore made of four Kir6.2 subunits and
four accompanying large SUR1 proteins belonging to the ABCC transporters
group. How SUR1 affects KATP function is not yet known; therefore,
we created simplified models of the Kir6.2 tetramer based on recently
determined cryo-EM KATP structures. Using all-atom molecular dynamics
(MD) with the CHARMM36 force field, targeted MD, and molecular docking,
we revealed functionally important rearrangements in the Kir6.2 pore,
induced by the presence of the SUR1 protein. The cytoplasmic domain
of Kir6.2 (CTD) is brought closer to the membrane due to interactions
with SUR1. Each Kir6.2 subunit has a conserved, functionally important,
disordered N-terminal tail. Using molecular docking, we found that
the Kir6.2 tail easily docks to the sulfonylurea drug binding region
located in the adjacent SUR1 protein. We reveal, for the first time,
dynamical behavior of the Kir6.2/SUR1 system, confirming a physiological
role of the Kir6.2 disordered tail, and we indicate structural determinants
of KATP-dependent insulin release from pancreatic β cells.
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Affiliation(s)
- Katarzyna Walczewska-Szewc
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziądzka 5, 87-100 Toruń, Poland.,Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wileńska 4, 87-100 Toruń, Poland
| | - Wiesław Nowak
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziądzka 5, 87-100 Toruń, Poland
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133
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Li Z, Guerrero F, Pérez de León AA, Foil LD, Swale DR. Small-Molecule Inhibitors of Inward Rectifier Potassium (Kir) Channels Reduce Bloodmeal Feeding and Have Insecticidal Activity Against the Horn Fly (Diptera: Muscidae). JOURNAL OF MEDICAL ENTOMOLOGY 2020; 57:1131-1140. [PMID: 32006426 DOI: 10.1093/jme/tjaa015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Indexed: 06/10/2023]
Abstract
Bloodmeal feeding by the horn fly, Haematobia irritans (L.), is associated with reduced milk production and blood loss that ultimately prevents weight gain of calves and yearlings. Thus, blood feeding by H. irritans causes significant economic losses in several continents. As with other arthropods, resistance to the majority of commercialized insecticides reduces the efficacy of current control programs. Thus, innovative technologies and novel biochemical targets for horn fly control are needed. Salivary gland and Malpighian tubule function are critical for H. irritans survivorship as they drive bloodmeal acquisition and maintain ion- and fluid homeostasis during bloodmeal processing, respectively. Experiments were conducted to test the hypothesis that pharmacological modulation of H. irritans inward rectifier potassium (Kir) channels would preclude blood feeding and induce mortality by reducing the secretory activity of the salivary gland while simultaneously inducing Malpighian tubule failure. Experimental results clearly indicate structurally diverse Kir channel modulators reduce the secretory activity of the salivary gland by up to fivefold when compared to control and the reduced saliva secretion was highly correlated to a reduction in bloodmeal acquisition in adult flies. Furthermore, adult feeding on blood treated with Kir channel modulators resulted in significant mortality. In addition to validating the Kir channels of H. irritans as putative insecticide targets, the knowledge gained from this study could be applied to develop novel therapeutic technologies targeting salivary gland or Malpighian tubule function to reduce the economic burden of horn fly ectoparasitism on cattle health and production.
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Affiliation(s)
- Zhilin Li
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA
| | | | - Adalberto A Pérez de León
- Knipling-Bushland Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, United States Department of Agriculture-Agricultural Research Service, Kerrville, TX
| | - Lane D Foil
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA
| | - Daniel R Swale
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA
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134
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Zhang X, Kang X, Jin L, Bai J, Zhang H, Liu W, Wang Z. ABCC9, NKAPL, and TMEM132C are potential diagnostic and prognostic markers in triple-negative breast cancer. Cell Biol Int 2020; 44:2002-2010. [PMID: 32544280 DOI: 10.1002/cbin.11406] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 06/05/2020] [Accepted: 06/13/2020] [Indexed: 12/29/2022]
Abstract
Triple-negative breast cancer (TNBC) is a highly heterogeneous disease. The aim of this study is to identify the diagnostic and poor prognostic signatures in TNBC by exploring the aberrant DNA methylation and gene expression. Differential expression and methylation analysis of the TNBC and paracancer samples from The Cancer Genome Atlas were performed. Gene set enrichment and protein-protein interaction (PPI) network analysis was used to explore the mechanisms of TNBC. Methylation-gene expression correlation analysis was performed, and multivariate Cox analysis and receiver operating characteristics analysis were used to further screen the hub genes for TNBC. We identified 1,525 differentially expressed genes and 150 differentially methylated genes between TNBC and paracancer samples. About 96.64% of the methylation sites were located on the CpG island. A total of 17 Gene Ontology biological process terms and 18 signal pathways were significantly enriched. GNG4, GNG11, PENK, MAOA, and AOX1 were identified as the core genes of the PPI network. Methylation-expression correlations revealed that ABCC9 (cg06951626), NKAPL (cg18675097, cg01031101, and cg17384889), and TMEM132C (cg03530754) showed promise as diagnostic and prognostic markers in TNBC. ABCC9 (cg06951626), NKAPL (cg18675097, cg01031101, and cg17384889), and TMEM132C (cg03530754) were potential diagnostic and prognostic markers in TNBC.
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Affiliation(s)
- Xiaoyu Zhang
- Thyroid and Breast Department III, Cangzhou Central Hospital, Cangzhou, Hebei, China
| | - Xiaoning Kang
- Ultrasound Department II, Cangzhou Central Hospital, Cangzhou, Hebei, China
| | - Lijun Jin
- Thyroid and Breast Department III, Cangzhou Central Hospital, Cangzhou, Hebei, China
| | - Jie Bai
- Thyroid and Breast Department III, Cangzhou Central Hospital, Cangzhou, Hebei, China
| | - Hui Zhang
- Thyroid and Breast Department III, Cangzhou Central Hospital, Cangzhou, Hebei, China
| | - Wei Liu
- Thyroid and Breast Department III, Cangzhou Central Hospital, Cangzhou, Hebei, China
| | - Zunyi Wang
- Thyroid and Breast Department III, Cangzhou Central Hospital, Cangzhou, Hebei, China
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135
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Hausenloy DJ, Schulz R, Girao H, Kwak BR, De Stefani D, Rizzuto R, Bernardi P, Di Lisa F. Mitochondrial ion channels as targets for cardioprotection. J Cell Mol Med 2020; 24:7102-7114. [PMID: 32490600 PMCID: PMC7339171 DOI: 10.1111/jcmm.15341] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 03/31/2020] [Accepted: 04/12/2020] [Indexed: 12/14/2022] Open
Abstract
Acute myocardial infarction (AMI) and the heart failure (HF) that often result remain the leading causes of death and disability worldwide. As such, new therapeutic targets need to be discovered to protect the myocardium against acute ischaemia/reperfusion (I/R) injury in order to reduce myocardial infarct (MI) size, preserve left ventricular function and prevent the onset of HF. Mitochondrial dysfunction during acute I/R injury is a critical determinant of cell death following AMI, and therefore, ion channels in the inner mitochondrial membrane, which are known to influence cell death and survival, provide potential therapeutic targets for cardioprotection. In this article, we review the role of mitochondrial ion channels, which are known to modulate susceptibility to acute myocardial I/R injury, and we explore their potential roles as therapeutic targets for reducing MI size and preventing HF following AMI.
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Affiliation(s)
- Derek J. Hausenloy
- Cardiovascular & Metabolic Disorders ProgramDuke‐National University of Singapore Medical SchoolSingaporeSingapore
- National Heart Research Institute SingaporeNational Heart CentreSingaporeSingapore
- Yong Loo Lin School of MedicineNational University SingaporeSingaporeSingapore
- The Hatter Cardiovascular InstituteUniversity College LondonLondonUK
- Cardiovascular Research CenterCollege of Medical and Health SciencesAsia UniversityTaichung CityTaiwan
| | - Rainer Schulz
- Institute of PhysiologyJustus‐Liebig University GiessenGiessenGermany
| | - Henrique Girao
- Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of MedicineUniversity of CoimbraCoimbraPortugal
- Center for Innovative Biomedicine and Biotechnology (CIBB)University of CoimbraCoimbraPortugal
- Clinical Academic Centre of CoimbraCACCCoimbraPortugal
| | - Brenda R. Kwak
- Department of Pathology and ImmunologyUniversity of GenevaGenevaSwitzerland
| | - Diego De Stefani
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Rosario Rizzuto
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
| | - Paolo Bernardi
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
- CNR Neuroscience InstitutePadovaItaly
| | - Fabio Di Lisa
- Department of Biomedical SciencesUniversity of PadovaPadovaItaly
- CNR Neuroscience InstitutePadovaItaly
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136
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In Silico Analysis of New Potent Anti-hyperglycemic Molecule for Diabetes Type 2 Management. Int J Pept Res Ther 2020. [DOI: 10.1007/s10989-019-09905-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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137
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Wu CI, Lu YY, Chen YC, Lin FZ, Huang JH, Lin YK, Higa S, Chan CS, Liu CM, Chen SA, Chen YJ. The AMP-activated protein kinase modulates hypothermia-induced J wave. Eur J Clin Invest 2020; 50:e13247. [PMID: 32307703 DOI: 10.1111/eci.13247] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 04/09/2020] [Accepted: 04/12/2020] [Indexed: 12/12/2022]
Abstract
BACKGROUND The mechanism underlying the occurrence of the J wave in low temperature remains unclear. However, low temperature is associated with metabolic disorder and 5' AMP-activated protein kinase (AMPK), which modulates ionic currents and cardiac metabolism. This study investigated whether AMPK regulation can modulate the occurrence of the J wave at low temperature. METHODS Unipolar and bipolar leads were used to record monophasic action potential (the endocardium and epicardium) and pseudo-electrocardiograms (inferior leads) to study the cardiac electrical activity. Measurements were taken in isolated Langendorff rabbit hearts at both 30℃ and 37℃ before and after administration of 4-aminopyridine (an ultrarapid delayed rectifier potassium current inhibitor, IKur , 50 µmol L-1 ), PF06409577 (an AMPK activator, 1 µmol L-1 ), compound C (an AMPK inhibitor, 10 µmol L-1 ) and glibenclamide (an ATP-sensitive inward rectifier potassium channel inhibitor, IKATP , 20 µmol L-1 ). RESULTS The amplitude of the J wave (2.46 ± 0.34 mV vs. 1.11 ± 0.23 mV, P < .01) at 30℃ (n = 15) was larger than that at 37℃ (n = 15). PF06409577 (1 µmol L-1 ) increased the J waves at both 30℃ and 37℃. In contrast, compound C (10 µmol L-1 ) reduced J wave at both 37℃ and 30℃. Low-temperature-induced J waves were individually suppressed by 4-AP (50 µmol L-1 ) and glibenclamide (20 µmol L-1 ). CONCLUSIONS AMPK inhibition reduces low-temperature-induced J waves and possible ventricular arrhythmogenesis by modulating IKATP and IKur channels.
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Affiliation(s)
- Cheng-I Wu
- Heart Rhythm Center, Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yen-Yu Lu
- Division of Cardiovascular Medicine, Department of Internal Medicine, Cathay General Hospital, Taipei, Taiwan
| | - Yao-Chang Chen
- Department of Biomedical Engineering and Institute of Physiology, National Defense Medical Center, Taipei, Taiwan
| | - Feng-Zhi Lin
- Grade Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Jen-Hung Huang
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Yung-Kuo Lin
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Satoshi Higa
- Cardiac Electrophysiology and Pacing Laboratory, Division of Cardiovascular Medicine, Makiminato Central Hospital, Okinawa, Japan
| | - Chao-Shun Chan
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chih-Min Liu
- Heart Rhythm Center, Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Shih-Ann Chen
- Heart Rhythm Center, Division of Cardiology, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yi-Jen Chen
- Division of Cardiovascular Medicine, Department of Internal Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Cardiovacular Research Center, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
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138
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Rodríguez C, Contreras C, Sáenz-Medina J, Muñoz M, Corbacho C, Carballido J, García-Sacristán A, Hernandez M, López M, Rivera L, Prieto D. Activation of the AMP-related kinase (AMPK) induces renal vasodilatation and downregulates Nox-derived reactive oxygen species (ROS) generation. Redox Biol 2020. [PMID: 32470915 DOI: 10.1016/j.redox.2020.101575.] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy sensor activated during energy stress to stimulate ATP production pathways and restore homeostasis. AMPK is widely expressed in the kidney and involved in mitochondrial protection and biogenesis upon acute renal ischemia, AMPK activity being blunted in metabolic disease-associated kidney disease. Since little is known about AMPK in the regulation of renal blood flow, the present study aimed to assess the role of AMPK in renal vascular function. Functional responses to the selective AMPK activator A769662 were assessed in intrarenal small arteries isolated from the kidney of renal tumour patients and Wistar rats and mounted in microvascular myographs to perform simultaneous measurements of intracellular calcium [Ca2+]i and tension. Superoxide (O2.-) and hydrogen peroxide (H2O2) production were measured by chemiluminescence and fluorescence and protein expression by Western blot. Activation of AMPK with A769662 increased AMPKα phosphorylation at Thr-172 and induced potent relaxations compared to AICAR in isolated human and rat intrarenal arteries, through both endothelium-dependent mechanisms involving nitric oxide (NO) and intermediate-conductance calcium-activated potassium (IKCa) channels, as well as activation of ATP-sensitive (KATP) channels and sarcoplasmic reticulum Ca2+-ATPase (SERCA) in vascular smooth muscle (VSM). Furthermore, AMPK activator reduced NADPH oxidase 4 (Nox4) and Nox2-derived reactive oxygen species (ROS) production. These results demonstrate that A769662 has potent vasodilator and antioxidant effects in intrarenal arteries. The benefits of AMPK activation in rat kidney are reproduced in human arteries and therefore vascular AMPK activation might be a therapeutic target in the treatment of metabolic disease-associated kidney injury.
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Affiliation(s)
- Claudia Rodríguez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Cristina Contreras
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Javier Sáenz-Medina
- Departamento de Urología, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain
| | - Mercedes Muñoz
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - César Corbacho
- Departamento de Anatomía Patológica, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain
| | - Joaquín Carballido
- Departamento de Urología, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain
| | | | - Medardo Hernandez
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Miguel López
- NeurObesity Group, Department of Physiology, CIMUS, Universidad de Santiago de Compostela-Instituto de Investigación Sanitaria, Santiago de Compostela, Spain
| | - Luis Rivera
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain
| | - Dolores Prieto
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense, Madrid, Spain.
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139
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Davis MJ, Kim HJ, Zawieja SD, Castorena-Gonzalez JA, Gui P, Li M, Saunders BT, Zinselmeyer BH, Randolph GJ, Remedi MS, Nichols CG. Kir6.1-dependent K ATP channels in lymphatic smooth muscle and vessel dysfunction in mice with Kir6.1 gain-of-function. J Physiol 2020; 598:3107-3127. [PMID: 32372450 DOI: 10.1113/jp279612] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2020] [Accepted: 05/01/2020] [Indexed: 02/06/2023] Open
Abstract
KEY POINTS Spontaneous contractions are essential for normal lymph transport and these contractions are exquisitely sensitive to the KATP channel activator pinacidil. KATP channel Kir6.1 and SUR2B subunits are expressed in mouse lymphatic smooth muscle (LSM) and form functional KATP channels as verified by electrophysiological techniques. Global deletion of Kir6.1 or SUR2 subunits results in severely impaired lymphatic contractile responses to pinacidil. Smooth muscle-specific expression of Kir6.1 gain-of-function mutant (GoF) subunits results in profound lymphatic contractile dysfunction and LSM hyperpolarization that is partially rescued by the KATP inhibitor glibenclamide. In contrast, lymphatic endothelial-specific expression of Kir6.1 GoF has essentially no effect on lymphatic contractile function. The high sensitivity of LSM to KATP channel GoF offers an explanation for the lymphoedema observed in patients with Cantú syndrome, a disorder caused by gain-of-function mutations in genes encoding Kir6.1 or SUR2, and suggests that glibenclamide may be an appropriate therapeutic agent. ABSTRACT This study aimed to understand the functional expression of KATP channel subunits in distinct lymphatic cell types, and assess the consequences of altered KATP channel activity on lymphatic pump function. KATP channel subunits Kir6.1 and SUR2B were expressed in mouse lymphatic muscle by PCR, but only Kir6.1 was expressed in lymphatic endothelium. Spontaneous contractions of popliteal lymphatics from wild-type (WT) (C57BL/6J) mice, assessed by pressure myography, were very sensitive to inhibition by the SUR2-specific KATP channel activator pinacidil, which hyperpolarized both mouse and human lymphatic smooth muscle (LSM). In vessels from mice with deletion of Kir6.1 (Kir6.1-/- ) or SUR2 (SUR2[STOP]) subunits, contractile parameters were not significantly different from those of WT vessels, suggesting that basal KATP channel activity in LSM is not an essential component of the lymphatic pacemaker, and does not exert a strong influence over contractile strength. However, these vessels were >100-fold less sensitive than WT vessels to pinacidil. Smooth muscle-specific expression of a Kir6.1 gain-of-function (GoF) subunit resulted in severely impaired lymphatic contractions and hyperpolarized LSM. Membrane potential and contractile activity was partially restored by the KATP channel inhibitor glibenclamide. In contrast, lymphatic endothelium-specific expression of Kir6.1 GoF subunits had negligible effects on lymphatic contraction frequency or amplitude. Our results demonstrate a high sensitivity of lymphatic contractility to KATP channel activators through activation of Kir6.1/SUR2-dependent channels in LSM. In addition, they offer an explanation for the lymphoedema observed in patients with Cantú syndrome, a disorder caused by gain-of-function mutations in genes encoding Kir6.1/SUR2.
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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
| | - Scott D Zawieja
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Jorge A Castorena-Gonzalez
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia, MO, 65212, USA
| | - Peichun Gui
- 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
| | - Brian T Saunders
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Bernd H Zinselmeyer
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Gwendalyn J Randolph
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Maria S Remedi
- Department of Medicine, Washington University School of Medicine, St Louis, MO, 63110, USA
| | - Colin G Nichols
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO, 63110, USA
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140
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Nakao Y, Koshimura M, Yamasaki T, Ohtubo Y. Cell-type-independent expression of inwardly rectifying potassium currents in mouse fungiform taste bud cells. Physiol Res 2020; 69:501-510. [PMID: 32469236 DOI: 10.33549/physiolres.934331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Inwardly rectifying potassium (Kir) channels play key roles in functions, including maintaining the resting membrane potential and regulating the action potential duration in excitable cells. Using in situ whole-cell recordings, we investigated Kir currents in mouse fungiform taste bud cells (TBCs) and immunologically identified the cell types (type I-III) expressing these currents. We demonstrated that Kir currents occur in a cell-type-independent manner. The activation potentials we measured were -80 to -90 mV, and the magnitude of the currents increased as the membrane potentials decreased, irrespective of the cell types. The maximum current densities at -120 mV showed no significant differences among cell types (p>0.05, one-way ANOVA). The density of Kir currents was not correlated with the density of either transient inward currents or outwardly rectifying currents, although there was significant correlation between transient inward and outwardly rectifying current densities (p<0.05, test for no correlation). RT-PCR studies employing total RNA extracted from peeled lingual epithelia detected mRNAs for Kir1, Kir2, Kir4, Kir6, and Kir7 families. These findings indicate that TBCs express several types of Kir channels functionally, which may contribute to regulation of the resting membrane potential and signal transduction of taste.
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Affiliation(s)
- Y Nakao
- Department of Human Intelligence Systems, Graduate School of Life Science and Systems Engineering, Kyushu Institute of Technology, Kitakyushu, Japan.
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141
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Zhang DM, Lin YF. Functional modulation of sarcolemmal K ATP channels by atrial natriuretic peptide-elicited intracellular signaling in adult rabbit ventricular cardiomyocytes. Am J Physiol Cell Physiol 2020; 319:C194-C207. [PMID: 32432931 DOI: 10.1152/ajpcell.00409.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ATP-sensitive potassium (KATP) channels couple cell metabolic status to membrane excitability and are crucial for stress adaptation and cytoprotection in the heart. Atrial natriuretic peptide (ANP), a cardiac peptide important for cardiovascular homeostasis, also exhibits cytoprotective features including protection against myocardial ischemia-reperfusion injuries. However, how ANP modulates cardiac KATP channels is largely unknown. In the present study we sought to address this issue by investigating the role of ANP signaling in functional modulation of sarcolemmal KATP (sarcKATP) channels in ventricular myocytes freshly isolated from adult rabbit hearts. Single-channel recordings were performed in combination with pharmacological approaches in the cell-attached patch configuration. Bath application of ANP markedly potentiated sarcKATP channel activities induced by metabolic inhibition with sodium azide, whereas the KATP-stimulating effect of ANP was abrogated by selective inhibition of the natriuretic peptide receptor type A (NPR-A), cGMP-dependent protein kinase (PKG), reactive oxygen species (ROS), extracellular signal-regulated protein kinase (ERK)1/2, Ca2+/calmodulin-dependent protein kinase II (CaMKII), or the ryanodine receptor (RyR). Blockade of RyRs also nullified hydrogen peroxide (H2O2)-induced stimulation of sarcKATP channels in intact cells. Furthermore, single-channel kinetic analyses revealed that ANP enhanced the function of ventricular sarcKATP channels through destabilizing the long closures and facilitating the opening transitions, without affecting the single-channel conductance. In conclusion, here we report that ANP positively modulates the activity of ventricular sarcKATP channels via an intracellular signaling mechanism consisting of NPR-A, PKG, ROS, ERK1/2, CaMKII, and RyR2. This novel mechanism may regulate cardiac excitability and contribute to cytoprotection, in part, by opening myocardial KATP channels.
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Affiliation(s)
- Dai-Min Zhang
- Department of Physiology and Membrane Biology, University of California, Davis, California
| | - Yu-Fung Lin
- Department of Physiology and Membrane Biology, University of California, Davis, California.,Department of Anesthesiology and Pain Medicine, University of California, Davis, California
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142
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Activation of the AMP-related kinase (AMPK) induces renal vasodilatation and downregulates Nox-derived reactive oxygen species (ROS) generation. Redox Biol 2020; 34:101575. [PMID: 32470915 PMCID: PMC7256643 DOI: 10.1016/j.redox.2020.101575] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Accepted: 05/10/2020] [Indexed: 12/19/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a cellular energy sensor activated during energy stress to stimulate ATP production pathways and restore homeostasis. AMPK is widely expressed in the kidney and involved in mitochondrial protection and biogenesis upon acute renal ischemia, AMPK activity being blunted in metabolic disease-associated kidney disease. Since little is known about AMPK in the regulation of renal blood flow, the present study aimed to assess the role of AMPK in renal vascular function. Functional responses to the selective AMPK activator A769662 were assessed in intrarenal small arteries isolated from the kidney of renal tumour patients and Wistar rats and mounted in microvascular myographs to perform simultaneous measurements of intracellular calcium [Ca2+]i and tension. Superoxide (O2.-) and hydrogen peroxide (H2O2) production were measured by chemiluminescence and fluorescence and protein expression by Western blot. Activation of AMPK with A769662 increased AMPKα phosphorylation at Thr-172 and induced potent relaxations compared to AICAR in isolated human and rat intrarenal arteries, through both endothelium-dependent mechanisms involving nitric oxide (NO) and intermediate-conductance calcium-activated potassium (IKCa) channels, as well as activation of ATP-sensitive (KATP) channels and sarcoplasmic reticulum Ca2+-ATPase (SERCA) in vascular smooth muscle (VSM). Furthermore, AMPK activator reduced NADPH oxidase 4 (Nox4) and Nox2-derived reactive oxygen species (ROS) production. These results demonstrate that A769662 has potent vasodilator and antioxidant effects in intrarenal arteries. The benefits of AMPK activation in rat kidney are reproduced in human arteries and therefore vascular AMPK activation might be a therapeutic target in the treatment of metabolic disease-associated kidney injury.
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143
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Grange DK, Roessler HI, McClenaghan C, Duran K, Shields K, Remedi MS, Knoers NVAM, Lee JM, Kirk EP, Scurr I, Smithson SF, Singh GK, van Haelst MM, Nichols CG, van Haaften G. Cantú syndrome: Findings from 74 patients in the International Cantú Syndrome Registry. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 181:658-681. [PMID: 31828977 DOI: 10.1002/ajmg.c.31753] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Revised: 10/14/2019] [Accepted: 10/18/2019] [Indexed: 11/11/2022]
Abstract
Cantú syndrome (CS), first described in 1982, is caused by pathogenic variants in ABCC9 and KCNJ8, which encode the regulatory and pore forming subunits of ATP-sensitive potassium (KATP ) channels, respectively. Multiple case reports of affected individuals have described the various clinical features of CS, but systematic studies are lacking. To define the effects of genetic variants on CS phenotypes and clinical outcomes, we have developed a standardized REDCap-based registry for CS. We report phenotypic features and associated genotypes on 74 CS subjects, with confirmed ABCC9 variants in 72 of the individuals. Hypertrichosis and a characteristic facial appearance are present in all individuals. Polyhydramnios during fetal life, hyperflexibility, edema, patent ductus arteriosus (PDA), cardiomegaly, dilated aortic root, vascular tortuosity of cerebral arteries, and migraine headaches are common features, although even with this large group of subjects, there is incomplete penetrance of CS-associated features, without clear correlation to genotype.
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Affiliation(s)
- Dorothy K Grange
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri.,Center for the Investigation of Membrane Excitability Diseases (CIMED)
| | - Helen I Roessler
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases (CIMED).,Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri
| | - Karen Duran
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Kathleen Shields
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Maria S Remedi
- Center for the Investigation of Membrane Excitability Diseases (CIMED).,Department of Medicine, Division of Endocrinology, Washington University School of Medicine, St. Louis, Missouri
| | - Nine V A M Knoers
- Department of Genetics, University Medical Center Utrecht, Utrecht University, Utrecht, the Netherlands.,Department of Genetics, University Medical Center Groningen, Groningen, the Netherlands
| | - Jin-Moo Lee
- Department of Neurology and Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - Edwin P Kirk
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, New South Wales, Australia.,School of Women's and Children's Health, University of New South Wales, Randwick, New South Wales, Australia
| | - Ingrid Scurr
- Department of Clinical Genetics, University Hospitals, Bristol, UK
| | - Sarah F Smithson
- Department of Clinical Genetics, University Hospitals, Bristol, UK
| | - Gautam K Singh
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri.,Center for the Investigation of Membrane Excitability Diseases (CIMED)
| | - Mieke M van Haelst
- Department of Clinical Genetics, VU Medical Center, VU University Amsterdam, Amsterdam, The Netherlands.,Department of Clinical Genetics, Amsterdam Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases (CIMED).,Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri
| | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
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144
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Severino P, D’Amato A, Pucci M, Infusino F, Birtolo LI, Mariani MV, Lavalle C, Maestrini V, Mancone M, Fedele F. Ischemic Heart Disease and Heart Failure: Role of Coronary Ion Channels. Int J Mol Sci 2020; 21:E3167. [PMID: 32365863 PMCID: PMC7246492 DOI: 10.3390/ijms21093167] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 04/28/2020] [Accepted: 04/28/2020] [Indexed: 01/09/2023] Open
Abstract
Heart failure is a complex syndrome responsible for high rates of death and hospitalization. Ischemic heart disease is one of the most frequent causes of heart failure and it is normally attributed to coronary artery disease, defined by the presence of one or more obstructive plaques, which determine a reduced coronary blood flow, causing myocardial ischemia and consequent heart failure. However, coronary obstruction is only an element of a complex pathophysiological process that leads to myocardial ischemia. In the literature, attention paid to the role of microcirculation, in the pathophysiology of ischemic heart disease and heart failure, is growing. Coronary microvascular dysfunction determines an inability of coronary circulation to satisfy myocardial metabolic demands, due to the imbalance of coronary blood flow regulatory mechanisms, including ion channels, leading to the development of hypoxia, fibrosis and tissue death, which may determine a loss of myocardial function, even beyond the presence of atherosclerotic epicardial plaques. For this reason, ion channels may represent the link among coronary microvascular dysfunction, ischemic heart disease and consequent heart failure.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Francesco Fedele
- Department of Clinical, Internal, Anesthesiology and Cardiovascular Sciences, Sapienza University of Rome, Viale del Policlinico, 155-00161 Rome, Italy; (P.S.); (A.D.); (M.P.); (F.I.); (L.I.B.); (M.V.M.); (C.L.); (V.M.); (M.M.)
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145
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Palmitoylation of the K ATP channel Kir6.2 subunit promotes channel opening by regulating PIP 2 sensitivity. Proc Natl Acad Sci U S A 2020; 117:10593-10602. [PMID: 32332165 DOI: 10.1073/pnas.1918088117] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A physiological role for long-chain acyl-CoA esters to activate ATP-sensitive K+ (KATP) channels is well established. Circulating palmitate is transported into cells and converted to palmitoyl-CoA, which is a substrate for palmitoylation. We found that palmitoyl-CoA, but not palmitic acid, activated the channel when applied acutely. We have altered the palmitoylation state by preincubating cells with micromolar concentrations of palmitic acid or by inhibiting protein thioesterases. With acyl-biotin exchange assays we found that Kir6.2, but not sulfonylurea receptor (SUR)1 or SUR2, was palmitoylated. These interventions increased the KATP channel mean patch current, increased the open time, and decreased the apparent sensitivity to ATP without affecting surface expression. Similar data were obtained in transfected cells, rat insulin-secreting INS-1 cells, and isolated cardiac myocytes. Kir6.2ΔC36, expressed without SUR, was also positively regulated by palmitoylation. Mutagenesis of Kir6.2 Cys166 prevented these effects. Clinical variants in KCNJ11 that affect Cys166 had a similar gain-of-function phenotype, but was more pronounced. Molecular modeling studies suggested that palmitoyl-C166 and selected large hydrophobic mutations make direct hydrophobic contact with Kir6.2-bound PIP2 Patch-clamp studies confirmed that palmitoylation of Kir6.2 at Cys166 enhanced the PIP2 sensitivity of the channel. Physiological relevance is suggested since palmitoylation blunted the regulation of KATP channels by α1-adrenoreceptor stimulation. The Cys166 residue is conserved in some other Kir family members (Kir6.1 and Kir3, but not Kir2), which are also subject to regulated palmitoylation, suggesting a general mechanism to control the open state of certain Kir channels.
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146
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Law NC, Marinelli I, Bertram R, Corbin KL, Schildmeyer C, Nunemaker CS. Chronic stimulation induces adaptive potassium channel activity that restores calcium oscillations in pancreatic islets in vitro. Am J Physiol Endocrinol Metab 2020; 318:E554-E563. [PMID: 32069073 PMCID: PMC7191410 DOI: 10.1152/ajpendo.00482.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Insulin pulsatility is important to hepatic response in regulating blood glucose. Growing evidence suggests that insulin-secreting pancreatic β-cells can adapt to chronic disruptions of pulsatility to rescue this physiologically important behavior. We determined the time scale for adaptation and examined potential ion channels underlying it. We induced the adaptation both by chronic application of the ATP-sensitive K+ [K(ATP)] channel blocker tolbutamide and by application of the depolarizing agent potassium chloride (KCl). Acute application of tolbutamide without pretreatment results in elevated Ca2+ as measured by fura-2AM and the loss of endogenous pulsatility. We show that after chronic exposure to tolbutamide (12-24 h), Ca2+ oscillations occur with subsequent acute tolbutamide application. The same experiment was conducted with potassium chloride (KCl) to directly depolarize the β-cells. Once again, following chronic exposure to the cell stimulator, the islets produced Ca2+ oscillations when subsequently exposed to tolbutamide. These experiments suggest that it is the chronic stimulation, and not tolbutamide desensitization, that is responsible for the adaptation that rescues oscillatory β-cell activity. This compensatory response also causes islet glucose sensitivity to shift rightward following chronic tolbutamide treatment. Mathematical modeling shows that a small increase in the number of K(ATP) channels in the membrane is one adaptation mechanism that is compatible with the data. To examine other compensatory mechanisms, pharmacological studies provide support that Kir2.1 and TEA-sensitive channels play some role. Overall, this investigation demonstrates β-cell adaptability to overstimulation, which is likely an important mechanism for maintaining glucose homeostasis in the face of chronic stimulation.
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Affiliation(s)
- Nathan C Law
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | | | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida
| | - Kathryn L Corbin
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Cara Schildmeyer
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
| | - Craig S Nunemaker
- Department of Biomedical Sciences Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
- Diabetes Institute, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio
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147
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Arita Y, Yoshinaga Y, Kaneko T, Kawahara Y, Nakamura K, Ohgi K, Arita S, Ryu T, Takase M, Sakagami R. Glyburide inhibits the bone resorption induced by traumatic occlusion in rats. J Periodontal Res 2020; 55:464-471. [PMID: 32153049 DOI: 10.1111/jre.12731] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/25/2019] [Accepted: 12/28/2019] [Indexed: 12/18/2022]
Abstract
OBJECTIVE To examine whether glyburide inhibits bone destruction caused by traumatic occlusion in a rat occlusal trauma model. BACKGROUND Excessive mechanical stress, such as traumatic occlusion, induces expression of IL-1β and may be involved in bone resorption. NLRP3 inflammasomes have been linked to IL-1β expression, but it is currently unclear whether glyburide, the inhibiter of NLRP3 inflammasome, suppresses occlusal trauma in rats. METHODS Male SD rats aged 7 weeks were used. In the trauma group, the occlusal surface of the maxillary first right molar was raised by attaching a metal wire to apply occlusal trauma to the mandibular first right molar. In the trauma + glyburide group, the NLRP3 inhibitor glyburide was administered orally every 24 hours from 1 day before induction of occlusal trauma. Rats were euthanized after 5 or 10 days, and the maxillary first molars were harvested with the adjacent tissues for histopathological investigation. Immunohistochemical expression of IL-1β, NLRP3, and RANKL was also assessed. RESULTS On day 5, bone resorption was significantly greater in the trauma group compared with the control group or the trauma + glyburide group, and there were significantly higher numbers of osteoclasts and cells positive for IL-1β, NLRP3, and RANKL in the trauma group. CONCLUSION In this study, glyburide inhibits bone resorption by traumatic occlusion in rats. It suggests that the NLRP3/IL-1β pathway might be associated with bone resorption induced by traumatic occlusion.
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Affiliation(s)
- Yoichi Arita
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
| | - Yasunori Yoshinaga
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan.,Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan
| | - Takashi Kaneko
- Center for Oral Diseases, Fukuoka Dental College, Fukuoka, Japan
| | - Yuri Kawahara
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
| | - Keiko Nakamura
- Center for Oral Diseases, Fukuoka Dental College, Fukuoka, Japan
| | - Kimiko Ohgi
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
| | - Seiichi Arita
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
| | - Takanori Ryu
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
| | - Minoru Takase
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
| | - Ryuji Sakagami
- Section of Periodontology, Department of Odontology, Fukuoka Dental College, Fukuoka, Japan
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148
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Martin GM, Sung MW, Shyng SL. Pharmacological chaperones of ATP-sensitive potassium channels: Mechanistic insight from cryoEM structures. Mol Cell Endocrinol 2020; 502:110667. [PMID: 31821855 PMCID: PMC6994177 DOI: 10.1016/j.mce.2019.110667] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/22/2019] [Accepted: 11/22/2019] [Indexed: 02/07/2023]
Abstract
ATP-sensitive potassium (KATP) channels are uniquely evolved protein complexes that couple cell energy levels to cell excitability. They govern a wide range of physiological processes including hormone secretion, neuronal transmission, vascular dilation, and cardiac and neuronal preconditioning against ischemic injuries. In pancreatic β-cells, KATP channels composed of Kir6.2 and SUR1, encoded by KCNJ11 and ABCC8, respectively, play a key role in coupling blood glucose concentration to insulin secretion. Mutations in ABCC8 or KCNJ11 that diminish channel function result in congenital hyperinsulinism. Many of these mutations principally hamper channel biogenesis and hence trafficking to the cell surface. Several small molecules have been shown to correct channel biogenesis and trafficking defects. Here, we review studies aimed at understanding how mutations impair channel biogenesis and trafficking and how pharmacological ligands overcome channel trafficking defects, particularly highlighting recent cryo-EM structural studies which have shed light on the mechanisms of channel assembly and pharmacological chaperones.
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Affiliation(s)
- Gregory M Martin
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Min Woo Sung
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, 97239, USA.
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149
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Papanicolaou KN, Ashok D, Liu T, Bauer TM, Sun J, Li Z, da Costa E, D'Orleans CC, Nathan S, Lefer DJ, Murphy E, Paolocci N, Foster DB, O'Rourke B. Global knockout of ROMK potassium channel worsens cardiac ischemia-reperfusion injury but cardiomyocyte-specific knockout does not: Implications for the identity of mitoKATP. J Mol Cell Cardiol 2020; 139:176-189. [PMID: 32004507 PMCID: PMC7849919 DOI: 10.1016/j.yjmcc.2020.01.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/16/2020] [Accepted: 01/23/2020] [Indexed: 01/29/2023]
Abstract
The renal-outer-medullary‑potassium (ROMK) channel, mutated in Bartter's syndrome, regulates ion exchange in kidney, but its extra-renal functions remain unknown. Additionally, ROMK was postulated to be the pore-forming subunit of the mitochondrial ATP-sensitive K+ channel (mitoKATP), a mediator of cardioprotection. Using global and cardiomyocyte-specific knockout mice (ROMK-GKO and ROMK-CKO respectively), we characterize the effects of ROMK knockout on mitochondrial ion handling, the response to pharmacological KATP channel modulators, and ischemia/reperfusion (I/R) injury. Mitochondria from ROMK-GKO hearts exhibited a lower threshold for Ca2+-triggered permeability transition pore (mPTP) opening but normal matrix volume changes during oxidative phosphorylation. Isolated perfused ROMK-GKO hearts exhibited impaired functional recovery and increased infarct size when I/R was preceded by an ischemic preconditioning (IPC) protocol. Because ROMK-GKO mice exhibited severe renal defects and cardiac remodeling, we further characterized ROMK-CKO hearts to avoid confounding systemic effects. Mitochondria from ROMK-CKO hearts had unchanged matrix volume responses during oxidative phosphorylation and still swelled upon addition of a mitoKATP opener, but exhibited a lower threshold for mPTP opening, similar to GKO mitochondria. Nevertheless, I/R induced damage was not exacerbated in ROMK-CKO hearts, either ex vivo or in vivo. Lastly, we examined the response of ROMK-CKO hearts to ex vivo I/R injury with or without IPC and found that IPC still protected these hearts, suggesting that cardiomyocyte ROMK does not participate significantly in the cardioprotective pathway elicited by IPC. Collectively, our findings from these novel strains of mice suggest that cardiomyocyte ROMK is not a central mediator of mitoKATP function, although it can affect mPTP activation threshold.
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Affiliation(s)
- Kyriakos N Papanicolaou
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Deepthi Ashok
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ting Liu
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Tyler M Bauer
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Junhui Sun
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Zhen Li
- Cardiovascular Center of Excellence, Louisiana State University (LSU) Health Sciences Center, New Orleans, LA, USA; Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA, USA
| | - Eduardo da Costa
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Charles Crepy D'Orleans
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Sara Nathan
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David J Lefer
- Cardiovascular Center of Excellence, Louisiana State University (LSU) Health Sciences Center, New Orleans, LA, USA; Department of Pharmacology and Experimental Therapeutics, LSU Health Sciences Center, New Orleans, LA, USA
| | - Elizabeth Murphy
- Cardiovascular Branch, NHLBI, NIH, 10 Center Drive, Bethesda, MD, USA
| | - Nazareno Paolocci
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - D Brian Foster
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Brian O'Rourke
- Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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150
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Huang Y, Hu D, Huang C, Nichols CG. Genetic Discovery of ATP-Sensitive K + Channels in Cardiovascular Diseases. Circ Arrhythm Electrophysiol 2020; 12:e007322. [PMID: 31030551 DOI: 10.1161/circep.119.007322] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The ATP-sensitive K+ (KATP) channels are hetero-octameric protein complexes comprising 4 pore-forming (Kir6.x) subunits and 4 regulatory sulfonylurea receptor (SURx) subunits. They are prominent in myocytes, pancreatic β cells, and neurons and link cellular metabolism with membrane excitability. Using genetically modified animals and genomic analysis in patients, recent studies have implicated certain ATP-sensitive K+ channel subtypes in physiological and pathological processes in a variety of cardiovascular diseases. In this review, we focus on the causal relationship between ATP-sensitive K+ channel activity and pathophysiology in the cardiovascular system, particularly from the perspective of genetic changes in human and animal models.
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Affiliation(s)
- Yan Huang
- Department of Cardiology, Renmin Hospital of Wuhan University; Cardiovascular Research Institute, Wuhan University, PR China (Y.H., D.H., C.H.).,Hubei Key Laboratory of Cardiology, Wuhan, PR China (Y.H., D.H., C.H.)
| | - Dan Hu
- Department of Cardiology, Renmin Hospital of Wuhan University; Cardiovascular Research Institute, Wuhan University, PR China (Y.H., D.H., C.H.).,Hubei Key Laboratory of Cardiology, Wuhan, PR China (Y.H., D.H., C.H.)
| | - Congxin Huang
- Department of Cardiology, Renmin Hospital of Wuhan University; Cardiovascular Research Institute, Wuhan University, PR China (Y.H., D.H., C.H.).,Hubei Key Laboratory of Cardiology, Wuhan, PR China (Y.H., D.H., C.H.)
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases and Department of Cell Biology and Physiology, Washington University School of Medicine, Saint Louis, MO (C.G.N.)
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