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Patton BL, Zhu P, ElSheikh A, Driggers CM, Shyng SL. Dynamic duo: Kir6 and SUR in K ATP channel structure and function. Channels (Austin) 2024; 18:2327708. [PMID: 38489043 PMCID: PMC10950283 DOI: 10.1080/19336950.2024.2327708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Accepted: 01/14/2024] [Indexed: 03/17/2024] Open
Abstract
KATP channels are ligand-gated potassium channels that couple cellular energetics with membrane potential to regulate cell activity. Each channel is an eight subunit complex comprising four central pore-forming Kir6 inward rectifier potassium channel subunits surrounded by four regulatory subunits known as the sulfonylurea receptor, SUR, which confer homeostatic metabolic control of KATP gating. SUR is an ATP binding cassette (ABC) protein family homolog that lacks membrane transport activity but is essential for KATP expression and function. For more than four decades, understanding the structure-function relationship of Kir6 and SUR has remained a central objective of clinical significance. Here, we review progress in correlating the wealth of functional data in the literature with recent KATP cryoEM structures.
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Affiliation(s)
- Bruce L. Patton
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Phillip Zhu
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Assmaa ElSheikh
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Camden M. Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, USA
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2
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Gao Z, Guan J, Yin S, Liu F. The role of ATP in sleep-wake regulation: In adenosine-dependent and -independent manner. Sleep Med 2024; 119:147-154. [PMID: 38678758 DOI: 10.1016/j.sleep.2024.04.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 03/31/2024] [Accepted: 04/23/2024] [Indexed: 05/01/2024]
Abstract
ATP plays a crucial role as an energy currency in the body's various physiological functions, including the regulation of the sleep-wake cycle. Evidence from genetics and pharmacology demonstrates a strong association between ATP metabolism and sleep. With the advent of new technologies such as optogenetics, genetically encoded biosensors, and novel ATP detection methods, the dynamic changes in ATP levels between different sleep states have been further uncovered. The classic mechanism for regulating sleep by ATP involves its conversion to adenosine, which increases sleep pressure when accumulated extracellularly. However, emerging evidence suggests that ATP can directly bind to P2 receptors and influence sleep-wake regulation through both adenosine-dependent and independent pathways. The outcome depends on the brain region where ATP acts and the expression type of P2 receptors. This review summarizes the experimental evidence on the relationship between ATP levels and changes in sleep states and outlines the mechanisms by which ATP is involved in regulating the sleep-wake cycle through both adenosine-dependent and independent pathways. Hopefully, this review will provide a comprehensive understanding of the current research basis and progress in this field and promote further investigations into the specific mechanisms of ATP in regulating sleep.
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Affiliation(s)
- Zhenfei Gao
- Shanghai Key Laboratory of Sleep Disordered Breathing, Department of Otolaryngology-Head and Neck Surgery, Otolaryngology Institute of Shanghai Jiaotong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China
| | - Jian Guan
- Shanghai Key Laboratory of Sleep Disordered Breathing, Department of Otolaryngology-Head and Neck Surgery, Otolaryngology Institute of Shanghai Jiaotong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
| | - Shankai Yin
- Shanghai Key Laboratory of Sleep Disordered Breathing, Department of Otolaryngology-Head and Neck Surgery, Otolaryngology Institute of Shanghai Jiaotong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
| | - Feng Liu
- Shanghai Key Laboratory of Sleep Disordered Breathing, Department of Otolaryngology-Head and Neck Surgery, Otolaryngology Institute of Shanghai Jiaotong University, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, 200233, China.
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3
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Brennan S, Chen S, Makwana S, Esposito S, McGuinness LR, Alnaimi AIM, Sims MW, Patel M, Aziz Q, Ojake L, Roberts JA, Sharma P, Lodwick D, Tinker A, Barrett-Jolley R, Dart C, Rainbow RD. Identification and characterisation of functional K ir6.1-containing ATP-sensitive potassium channels in the cardiac ventricular sarcolemmal membrane. Br J Pharmacol 2024. [PMID: 38763521 DOI: 10.1111/bph.16390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/21/2024] [Accepted: 03/18/2024] [Indexed: 05/21/2024] Open
Abstract
BACKGROUND AND PURPOSE The canonical Kir6.2/SUR2A ventricular KATP channel is highly ATP-sensitive and remains closed under normal physiological conditions. These channels activate only when prolonged metabolic compromise causes significant ATP depletion and then shortens the action potential to reduce contractile activity. Pharmacological activation of KATP channels is cardioprotective, but physiologically, it is difficult to understand how these channels protect the heart if they only open under extreme metabolic stress. The presence of a second KATP channel population could help explain this. Here, we characterise the biophysical and pharmacological behaviours of a constitutively active Kir6.1-containing KATP channel in ventricular cardiomyocytes. EXPERIMENTAL APPROACH Patch-clamp recordings from rat ventricular myocytes in combination with well-defined pharmacological modulators was used to characterise these newly identified K+ channels. Action potential recording, calcium (Fluo-4) fluorescence measurements and video edge detection of contractile function were used to assess functional consequences of channel modulation. KEY RESULTS Our data show a ventricular K+ conductance whose biophysical characteristics and response to pharmacological modulation were consistent with Kir6.1-containing channels. These Kir6.1-containing channels lack the ATP-sensitivity of the canonical channels and are constitutively active. CONCLUSION AND IMPLICATIONS We conclude there are two functionally distinct populations of ventricular KATP channels: constitutively active Kir6.1-containing channels that play an important role in fine-tuning the action potential and Kir6.2/SUR2A channels that activate with prolonged ischaemia to impart late-stage protection against catastrophic ATP depletion. Further research is required to determine whether Kir6.1 is an overlooked target in Comprehensive in vitro Proarrhythmia Assay (CiPA) cardiac safety screens.
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Affiliation(s)
- Sean Brennan
- Department of Cardiovascular and Metabolic Medicine and Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
| | - Shen Chen
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Samir Makwana
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Simona Esposito
- Department of Cardiovascular and Metabolic Medicine and Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Lauren R McGuinness
- Department of Cardiovascular and Metabolic Medicine and Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
| | - Abrar I M Alnaimi
- Department of Cardiovascular and Metabolic Medicine and Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
- Department of Cardiac Technology, Imam Abdulrahman Bin Faisal University, Dammam, Saudi Arabia
| | - Mark W Sims
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Manish Patel
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Qadeer Aziz
- William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Leona Ojake
- William Harvey Research Institute, Queen Mary University of London, London, UK
| | - James A Roberts
- Department of Cardiovascular and Metabolic Medicine and Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
| | - Parveen Sharma
- Department of Cardiovascular and Metabolic Medicine and Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
| | - David Lodwick
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Andrew Tinker
- William Harvey Research Institute, Queen Mary University of London, London, UK
| | - Richard Barrett-Jolley
- Department of Musculoskeletal and Ageing Science, University of Liverpool, Liverpool, UK
| | - Caroline Dart
- Department of Biochemistry, Cell and Systems Biology, University of Liverpool, Liverpool, UK
| | - Richard D Rainbow
- Department of Cardiovascular and Metabolic Medicine and Liverpool Centre for Cardiovascular Science, University of Liverpool, Liverpool, UK
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Efthymiou S, Scala M, Nagaraj V, Ochenkowska K, Komdeur FL, Liang RA, Abdel-Hamid MS, Sultan T, Barøy T, Van Ghelue M, Vona B, Maroofian R, Zafar F, Alkuraya FS, Zaki MS, Severino M, Duru KC, Tryon RC, Brauteset LV, Ansari M, Hamilton M, van Haelst MM, van Haaften G, Zara F, Houlden H, Samarut É, Nichols CG, Smeland MF, McClenaghan C. Novel loss-of-function variants expand ABCC9-related intellectual disability and myopathy syndrome. Brain 2024; 147:1822-1836. [PMID: 38217872 PMCID: PMC11068106 DOI: 10.1093/brain/awae010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 11/22/2023] [Accepted: 12/30/2023] [Indexed: 01/15/2024] Open
Abstract
Loss-of-function mutation of ABCC9, the gene encoding the SUR2 subunit of ATP sensitive-potassium (KATP) channels, was recently associated with autosomal recessive ABCC9-related intellectual disability and myopathy syndrome (AIMS). Here we identify nine additional subjects, from seven unrelated families, harbouring different homozygous loss-of-function variants in ABCC9 and presenting with a conserved range of clinical features. All variants are predicted to result in severe truncations or in-frame deletions within SUR2, leading to the generation of non-functional SUR2-dependent KATP channels. Affected individuals show psychomotor delay and intellectual disability of variable severity, microcephaly, corpus callosum and white matter abnormalities, seizures, spasticity, short stature, muscle fatigability and weakness. Heterozygous parents do not show any conserved clinical pathology but report multiple incidences of intra-uterine fetal death, which were also observed in an eighth family included in this study. In vivo studies of abcc9 loss-of-function in zebrafish revealed an exacerbated motor response to pentylenetetrazole, a pro-convulsive drug, consistent with impaired neurodevelopment associated with an increased seizure susceptibility. Our findings define an ABCC9 loss-of-function-related phenotype, expanding the genotypic and phenotypic spectrum of AIMS and reveal novel human pathologies arising from KATP channel dysfunction.
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Affiliation(s)
- Stephanie Efthymiou
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Marcello Scala
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16147 Genoa, Italy
- U.O.C. Genetica Medica, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Vini Nagaraj
- Center for Advanced Biotechnology and Medicine, and Departments of Pharmacology and Medicine, Robert Wood Johnson Medical School, Rutgers the State University of New Jersey, Piscatway, NJ 08854, USA
| | - Katarzyna Ochenkowska
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), and Department of Neuroscience, Université de Montréal, Montreal H2X 0A9, Quebec, Canada
| | - Fenne L Komdeur
- Section Clinical Genetics, Department of Human Genetics and Amsterdam Reproduction and Development, Amsterdam University Medical Centers, 1105 AZ, Amsterdam, The Netherlands
| | - Robin A Liang
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, 9019 Tromsø, Norway
| | - Mohamed S Abdel-Hamid
- Medical Molecular Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | - Tipu Sultan
- Department of Pediatric Neurology, Children Hospital, University of Child Health Sciences, Lahore, Punjab 54000, Pakistan
| | - Tuva Barøy
- Department of Medical Genetics, Oslo University Hospital, 0450 Oslo, Norway
| | - Marijke Van Ghelue
- Department of Medical Genetics, Division of Child and Adolescent Health, University Hospital of North Norway, 9019 Tromsø, Norway
| | - Barbara Vona
- Institute of Human Genetics and Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, 37073 Göttingen, Germany
| | - Reza Maroofian
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Faisal Zafar
- Department of Paediatric Neurology, Children’s Hospital and Institute of Child Health, Multan, Punjab 60000, Pakistan
| | - Fowzan S Alkuraya
- Department of Translational Genomics, Center for Genomic Medicine, King Faisal Specialist Hospital and Research Center, Riyadh 12713, Saudi Arabia
| | - Maha S Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Institute, National Research Centre, Cairo 12622, Egypt
| | | | - Kingsley C Duru
- Center for Advanced Biotechnology and Medicine, and Departments of Pharmacology and Medicine, Robert Wood Johnson Medical School, Rutgers the State University of New Jersey, Piscatway, NJ 08854, USA
| | - Robert C Tryon
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO 63110, USA
| | - Lin Vigdis Brauteset
- Division of Habilitation for Children, Innlandet Hospital Sanderud, Hamar 2312, Norway
| | - Morad Ansari
- South East Scotland Genetic Service, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Mark Hamilton
- West of Scotland Clinical Genetics Service, Queen Elizabeth University Hospital, Glasgow G51 4TF, UK
| | - Mieke M van Haelst
- Section Clinical Genetics, Department of Human Genetics and Amsterdam Reproduction and Development, Amsterdam University Medical Centers, 1105 AZ, Amsterdam, The Netherlands
| | - Gijs van Haaften
- Department of Genetics, University Medical Center, Utrecht, 3584 CX, The Netherlands
| | - Federico Zara
- U.O.C. Genetica Medica, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Éric Samarut
- Centre de Recherche du Centre Hospitalier de l’Université de Montréal (CRCHUM), and Department of Neuroscience, Université de Montréal, Montreal H2X 0A9, Quebec, Canada
| | - Colin G Nichols
- Department of Cell Biology and Physiology, and Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University, St Louis, MO 63110, USA
| | - Marie F Smeland
- Department of Pediatric Rehabilitation, University Hospital of North Norway, 9019 Tromsø, Norway
- Institute of Clinical Medicine, UiT The Arctic University of Norway, 9019, Tromsø, Norway
| | - Conor McClenaghan
- Center for Advanced Biotechnology and Medicine, and Departments of Pharmacology and Medicine, Robert Wood Johnson Medical School, Rutgers the State University of New Jersey, Piscatway, NJ 08854, USA
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Fitts RH, Wang X, Kwok WM, Camara AKS. Cardiomyocyte Adaptation to Exercise: K+ Channels, Contractility and Ischemic Injury. Int J Sports Med 2024. [PMID: 38648799 DOI: 10.1055/a-2296-7604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024]
Abstract
Cardiovascular disease is a leading cause of morbidity and mortality, and exercise-training (TRN) is known to reduce risk factors and protect the heart from ischemia and reperfusion injury. Though the cardioprotective effects of exercise are well-documented, underlying mechanisms are not well understood. This review highlights recent findings and focuses on cardiac factors with emphasis on K+ channel control of the action potential duration (APD), β-adrenergic and adenosine regulation of cardiomyocyte function, and mitochondrial Ca2+ regulation. TRN-induced prolongation and shortening of the APD at low and high activation rates, respectively, is discussed in the context of a reduced response of the sarcolemma delayed rectifier potassium channel (IK) and increased content and activation of the sarcolemma KATP channel. A proposed mechanism underlying the latter is presented, including the phosphatidylinositol-3kinase/protein kinase B pathway. TRN induced increases in cardiomyocyte contractility and the response to adrenergic agonists are discussed. The TRN-induced protection from reperfusion injury is highlighted by the increased content and activation of the sarcolemma KATP channel and the increased phosphorylated glycogen synthase kinase-3β, which aid in preventing mitochondrial Ca2+ overload and mitochondria-triggered apoptosis. Finally, a brief section is presented on the increased incidences of atrial fibrillation associated with age and in life-long exercisers.
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Affiliation(s)
- Robert H Fitts
- Biological Sciences, Marquette University, Milwaukee, United States
| | - Xinrui Wang
- Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, United States
| | - Wai-Meng Kwok
- Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, United States
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, United States
- Anesthesiology, Medical College of Wisconsin, Milwaukee, United States
- Cancer Center, Medical College of Wisconsin, Milwaukee, United States
| | - Amadou K S Camara
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, United States
- Anesthesiology, Medical College of Wisconsin, Milwaukee, United States
- Cancer Center, Medical College of Wisconsin, Milwaukee, United States
- Physiology, Medical College of Wisconsin, Milwaukee, United States
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6
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Rodríguez-Rivera NS, Barrera-Oviedo D. Exploring the Pathophysiology of ATP-Dependent Potassium Channels in Insulin Resistance. Int J Mol Sci 2024; 25:4079. [PMID: 38612888 PMCID: PMC11012456 DOI: 10.3390/ijms25074079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 03/15/2024] [Accepted: 03/29/2024] [Indexed: 04/14/2024] Open
Abstract
Ionic channels are present in eucaryotic plasma and intracellular membranes. They coordinate and control several functions. Potassium channels belong to the most diverse family of ionic channels that includes ATP-dependent potassium (KATP) channels in the potassium rectifier channel subfamily. These channels were initially described in heart muscle and then in other tissues such as pancreatic, skeletal muscle, brain, and vascular and non-vascular smooth muscle tissues. In pancreatic beta cells, KATP channels are primarily responsible for maintaining the membrane potential and for depolarization-mediated insulin release, and their decreased density and activity may be related to insulin resistance. KATP channels' relationship with insulin resistance is beginning to be explored in extra-pancreatic beta tissues like the skeletal muscle, where KATP channels are involved in insulin-dependent glucose recapture and their activation may lead to insulin resistance. In adipose tissues, KATP channels containing Kir6.2 protein subunits could be related to the increase in free fatty acids and insulin resistance; therefore, pathological processes that promote prolonged adipocyte KATP channel inhibition might lead to obesity due to insulin resistance. In the central nervous system, KATP channel activation can regulate peripheric glycemia and lead to brain insulin resistance, an early peripheral alteration that can lead to the development of pathologies such as obesity and Type 2 Diabetes Mellitus (T2DM). In this review, we aim to discuss the characteristics of KATP channels, their relationship with clinical disorders, and their mechanisms and potential associations with peripheral and central insulin resistance.
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Affiliation(s)
- Nidia Samara Rodríguez-Rivera
- Laboratorio de Farmacología y Bioquímica Clínica, Departamento de Farmacología, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico;
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7
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Gest AMM, Lazzari-Dean JR, Ortiz G, Yaeger-Weiss SK, Boggess SC, Miller EW. A red-emitting carborhodamine for monitoring and measuring membrane potential. Proc Natl Acad Sci U S A 2024; 121:e2315264121. [PMID: 38551837 PMCID: PMC10998576 DOI: 10.1073/pnas.2315264121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 01/25/2024] [Indexed: 04/02/2024] Open
Abstract
Biological membrane potentials, or voltages, are a central facet of cellular life. Optical methods to visualize cellular membrane voltages with fluorescent indicators are an attractive complement to traditional electrode-based approaches, since imaging methods can be high throughput, less invasive, and provide more spatial resolution than electrodes. Recently developed fluorescent indicators for voltage largely report changes in membrane voltage by monitoring voltage-dependent fluctuations in fluorescence intensity. However, it would be useful to be able to not only monitor changes but also measure values of membrane potentials. This study discloses a fluorescent indicator which can address both. We describe the synthesis of a sulfonated tetramethyl carborhodamine fluorophore. When this carborhodamine is conjugated with an electron-rich, methoxy (-OMe) containing phenylenevinylene molecular wire, the resulting molecule, CRhOMe, is a voltage-sensitive fluorophore with red/far-red fluorescence. Using CRhOMe, changes in cellular membrane potential can be read out using fluorescence intensity or lifetime. In fluorescence intensity mode, CRhOMe tracks fast-spiking neuronal action potentials (APs) with greater signal-to-noise than state-of-the-art BeRST 1 (another voltage-sensitive fluorophore). CRhOMe can also measure values of membrane potential. The fluorescence lifetime of CRhOMe follows a single exponential decay, substantially improving the quantification of membrane potential values using fluorescence lifetime imaging microscopy (FLIM). The combination of red-shifted excitation and emission, mono-exponential decay, and high voltage sensitivity enable fast FLIM recording of APs in cardiomyocytes. The ability to both monitor and measure membrane potentials with red light using CRhOMe makes it an important approach for studying biological voltages.
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Affiliation(s)
| | | | - Gloria Ortiz
- Department of Chemistry, University of California, Berkeley, CA 94720
| | | | - Steven C Boggess
- Department of Chemistry, University of California, Berkeley, CA 94720
| | - Evan W Miller
- Department of Chemistry, University of California, Berkeley, CA 94720
- Department of Molecular & Cell Biology, University of California, Berkeley, CA 94720
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720
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8
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Enders-Seidlitz H, Raile K, Gong M, Galler A, Kuehnen P, Wiegand S. Insulin Secretion Defect in Children and Adolescents with Obesity: Clinical and Molecular Genetic Characterization. J Diabetes Res 2024; 2024:5558634. [PMID: 38550917 PMCID: PMC10977255 DOI: 10.1155/2024/5558634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 02/02/2024] [Accepted: 02/22/2024] [Indexed: 04/02/2024] Open
Abstract
Introduction Childhood obesity is increasing worldwide and presents as a global health issue due to multiple metabolic comorbidities. About 1% of adolescents with obesity develop type 2 diabetes (T2D); however, little is known about the genetic and pathophysiological background at young age. The objective of this study was to assess the prevalence of impaired glucose regulation (IGR) in a large cohort of children and adolescents with obesity and to characterize insulin sensitivity and insulin secretion. We also wanted to investigate adolescents with insulin secretion disorder more closely and analyze possible candidate genes of diabetes in a subcohort. Methods We included children and adolescents with obesity who completed an oral glucose tolerance test (OGTT, glucose + insulin) in the outpatient clinic. We calculated Matsuda index, the area under the curve (AUC (Ins/Glu)), and an oral disposition index (ISSI-2) to estimate insulin resistance and beta-cell function. We identified patients with IGR and low insulin secretion (maximum insulin during OGTT < 200 mU/l) and tested a subgroup using next generation sequencing to identify possible mutations in 103 candidate genes. Results The total group consisted of 903 children and adolescents with obesity. 4.5% showed impaired fasting glucose, 9.4% impaired glucose tolerance, and 1.2% T2D. Matsuda index and Total AUC (Ins/Glu) showed a hyperbolic relationship. Out of 39 patients with low insulin secretion, we performed genetic testing on 12 patients. We found five monogenetic defects (ABCC8 (n = 3), GCK (n = 1), and GLI2/PTF1A (n = 1)). Conclusion Using surrogate parameters of beta-cell function and insulin resistance can help identify patients with insulin secretion disorder. A prevalence of 40% mutations of known diabetes genes in the subgroup with low insulin secretion suggests that at least 1.7% of patients with adolescent obesity have monogenic diabetes. A successful molecular genetic diagnosis can help to improve individual therapy.
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Affiliation(s)
| | | | - Maolian Gong
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
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9
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Driggers CM, Kuo YY, Zhu P, ElSheikh A, Shyng SL. Structure of an open K ATP channel reveals tandem PIP 2 binding sites mediating the Kir6.2 and SUR1 regulatory interface. Nat Commun 2024; 15:2502. [PMID: 38509107 PMCID: PMC10954709 DOI: 10.1038/s41467-024-46751-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 03/08/2024] [Indexed: 03/22/2024] Open
Abstract
ATP-sensitive potassium (KATP) channels, composed of four pore-lining Kir6.2 subunits and four regulatory sulfonylurea receptor 1 (SUR1) subunits, control insulin secretion in pancreatic β-cells. KATP channel opening is stimulated by PIP2 and inhibited by ATP. Mutations that increase channel opening by PIP2 reduce ATP inhibition and cause neonatal diabetes. Although considerable evidence has implicated a role for PIP2 in KATP channel function, previously solved open-channel structures have lacked bound PIP2, and mechanisms by which PIP2 regulates KATP channels remain unresolved. Here, we report the cryoEM structure of a KATP channel harboring the neonatal diabetes mutation Kir6.2-Q52R, in the open conformation, bound to amphipathic molecules consistent with natural C18:0/C20:4 long-chain PI(4,5)P2 at two adjacent binding sites between SUR1 and Kir6.2. The canonical PIP2 binding site is conserved among PIP2-gated Kir channels. The non-canonical PIP2 binding site forms at the interface of Kir6.2 and SUR1. Functional studies demonstrate both binding sites determine channel activity. Kir6.2 pore opening is associated with a twist of the Kir6.2 cytoplasmic domain and a rotation of the N-terminal transmembrane domain of SUR1, which widens the inhibitory ATP binding pocket to disfavor ATP binding. The open conformation is particularly stabilized by the Kir6.2-Q52R residue through cation-π bonding with SUR1-W51. Together, these results uncover the cooperation between SUR1 and Kir6.2 in PIP2 binding and gating, explain the antagonistic regulation of KATP channels by PIP2 and ATP, and provide a putative mechanism by which Kir6.2-Q52R stabilizes an open channel to cause neonatal diabetes.
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Affiliation(s)
- Camden M Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA.
| | - Yi-Ying Kuo
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Phillip Zhu
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
| | - Assmaa ElSheikh
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, 97239, USA.
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10
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Hou T, Chen L. Sulfonylurea receptor 2 (SUR2), intricate sensors for intracellular Mg-nucleotides. Bioessays 2024; 46:e2300151. [PMID: 38227376 DOI: 10.1002/bies.202300151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 12/19/2023] [Accepted: 12/21/2023] [Indexed: 01/17/2024]
Abstract
SUR2, similar to SUR1, is a regulatory subunit of the ATP-sensitive potassium channel (KATP), which plays a key role in numerous important physiological processes and is implicated in various diseases. Recent structural studies have revealed that, like SUR1, SUR2 can undergo ligand-dependent dynamic conformational changes, transitioning between an inhibitory inward-facing conformation and an activating occluded conformation. In addition, SUR2 possesses a unique inhibitory Regulatory helix (R helix) that is absent in SUR1. The binding of the activating Mg-ADP to NBD2 of SUR2 competes with the inhibitory Mg-ATP, thereby promoting the release of the R helix and initiating the activation process. Moreover, the signal generated by Mg-ADP binding to NBD2 might be directly transmitted to the TMD of SUR2, prior to NBD dimerization. Furthermore, the C-terminal 42 residues (C42) of SUR2 might allosterically regulate the kinetics of Mg-nucleotide binding on NBD2. These distinctive properties render SUR2 intricate sensors for intracellular Mg-nucleotides.
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Affiliation(s)
- Tianyi Hou
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, Beijing, China
- National Biomedical Imaging Center, Peking University, Beijing, Beijing, China
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11
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Li K, McClenahan SJ, Han C, Bungard JD, Rathnayake U, Boutaud O, Bauer JA, Days EL, Lindsley CW, Shelton EL, Denton JS. Discovery and Characterization of VU0542270, the First Selective Inhibitor of Vascular Kir6.1/SUR2B K ATP Channels. Mol Pharmacol 2024; 105:202-212. [PMID: 38302135 PMCID: PMC10877733 DOI: 10.1124/molpharm.123.000783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 12/21/2023] [Accepted: 01/02/2024] [Indexed: 02/03/2024] Open
Abstract
Vascular smooth muscle KATP channels critically regulate blood flow and blood pressure by modulating vascular tone and therefore represent attractive drug targets for treating several cardiovascular disorders. However, the lack of potent inhibitors that can selectively inhibit Kir6.1/SUR2B (vascular KATP) over Kir6.2/SUR1 (pancreatic KATP) has eluded discovery despite decades of intensive research. We therefore screened 47,872 chemically diverse compounds for novel inhibitors of heterologously expressed Kir6.1/SUR2B channels. The most potent inhibitor identified in the screen was an N-aryl-N'-benzyl urea compound termed VU0542270. VU0542270 inhibits Kir6.1/SUR2B with an IC50 of approximately 100 nM but has no apparent activity toward Kir6.2/SUR1 or several other members of the Kir channel family at doses up to 30 µM (>300-fold selectivity). By expressing different combinations of Kir6.1 or Kir6.2 with SUR1, SUR2A, or SUR2B, the VU0542270 binding site was localized to SUR2. Initial structure-activity relationship exploration around VU0542270 revealed basic texture related to structural elements that are required for Kir6.1/SUR2B inhibition. Analysis of the pharmacokinetic properties of VU0542270 showed that it has a short in vivo half-life due to extensive metabolism. In pressure myography experiments on isolated mouse ductus arteriosus vessels, VU0542270 induced ductus arteriosus constriction in a dose-dependent manner similar to that of the nonspecific KATP channel inhibitor glibenclamide. The discovery of VU0542270 provides conceptual proof that SUR2-specific KATP channel inhibitors can be developed using a molecular target-based approach and offers hope for developing cardiovascular therapeutics targeting Kir6.1/SUR2B. SIGNIFICANCE STATEMENT: Small-molecule inhibitors of vascular smooth muscle KATP channels might represent novel therapeutics for patent ductus arteriosus, migraine headache, and sepsis; however, the lack of selective channel inhibitors has slowed progress in these therapeutic areas. Here, this study describes the discovery and characterization of the first vascular-specific KATP channel inhibitor, VU0542270.
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Affiliation(s)
- Kangjun Li
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Samantha J McClenahan
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Changho Han
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Joseph D Bungard
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Upendra Rathnayake
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Olivier Boutaud
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Joshua A Bauer
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Emily L Days
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Craig W Lindsley
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Elaine L Shelton
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
| | - Jerod S Denton
- Departments of Anesthesiology (K.L., S.J.M., J.S.D.), Pharmacology (K.L., C.H., J.D.B., U.R., O.B., C.W.L., J.S.D.), Pediatrics (E.L.S.), and Biochemistry (J.A.B.), Vanderbilt University Medical Center, Nashville, Tennessee and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee (J.A.B., E.L.D., J.S.D.)
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12
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Moon DO. Exploring the Role of Surface and Mitochondrial ATP-Sensitive Potassium Channels in Cancer: From Cellular Functions to Therapeutic Potentials. Int J Mol Sci 2024; 25:2129. [PMID: 38396807 PMCID: PMC10888650 DOI: 10.3390/ijms25042129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/08/2024] [Accepted: 02/08/2024] [Indexed: 02/25/2024] Open
Abstract
ATP-sensitive potassium (KATP) channels are found in plasma membranes and mitochondria. These channels are a type of ion channel that is regulated by the intracellular concentration of adenosine triphosphate (ATP) and other nucleotides. In cell membranes, they play a crucial role in linking metabolic activity to electrical activity, especially in tissues like the heart and pancreas. In mitochondria, KATP channels are involved in protecting cells against ischemic damage and regulating mitochondrial function. This review delves into the role of KATP channels in cancer biology, underscoring their critical function. Notably responsive to changes in cellular metabolism, KATP channels link metabolic states to electrical activity, a feature that becomes particularly significant in cancer cells. These cells, characterized by uncontrolled growth, necessitate unique metabolic and signaling pathways, differing fundamentally from normal cells. Our review explores the intricate roles of KATP channels in influencing the metabolic and ionic balance within cancerous cells, detailing their structural and operational mechanisms. We highlight the channels' impact on cancer cell survival, proliferation, and the potential of KATP channels as therapeutic targets in oncology. This includes the challenges in targeting these channels due to their widespread presence in various tissues and the need for personalized treatment strategies. By integrating molecular biology, physiology, and pharmacology perspectives, the review aims to enhance the understanding of cancer as a complex metabolic disease and to open new research and treatment avenues by focusing on KATP channels. This comprehensive approach provides valuable insights into the potential of KATP channels in developing innovative cancer treatments.
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Affiliation(s)
- Dong-Oh Moon
- Department of Biology Education, Daegu University, 201, Daegudae-ro, Gyeongsan-si 38453, Gyeongsangbuk-do, Republic of Korea
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13
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Longden TA, Lederer WJ. Electro-metabolic signaling. J Gen Physiol 2024; 156:e202313451. [PMID: 38197953 PMCID: PMC10783436 DOI: 10.1085/jgp.202313451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/27/2023] [Accepted: 12/14/2023] [Indexed: 01/11/2024] Open
Abstract
Precise matching of energy substrate delivery to local metabolic needs is essential for the health and function of all tissues. Here, we outline a mechanistic framework for understanding this critical process, which we refer to as electro-metabolic signaling (EMS). All tissues exhibit changes in metabolism over varying spatiotemporal scales and have widely varying energetic needs and reserves. We propose that across tissues, common signatures of elevated metabolism or increases in energy substrate usage that exceed key local thresholds rapidly engage mechanisms that generate hyperpolarizing electrical signals in capillaries that then relax contractile elements throughout the vasculature to quickly adjust blood flow to meet changing needs. The attendant increase in energy substrate delivery serves to meet local metabolic requirements and thus avoids a mismatch in supply and demand and prevents metabolic stress. We discuss in detail key examples of EMS that our laboratories have discovered in the brain and the heart, and we outline potential further EMS mechanisms operating in tissues such as skeletal muscle, pancreas, and kidney. We suggest that the energy imbalance evoked by EMS uncoupling may be central to cellular dysfunction from which the hallmarks of aging and metabolic diseases emerge and may lead to generalized organ failure states-such as diverse flavors of heart failure and dementia. Understanding and manipulating EMS may be key to preventing or reversing these dysfunctions.
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Affiliation(s)
- Thomas A. Longden
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - W. Jonathan Lederer
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- Laboratory of Molecular Cardiology, Center for Biomedical Engineering and Technology, University of Maryland School of Medicine, Baltimore, MD, USA
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14
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Yang Y, Chen L. Functional dissection of KATP channel structures reveals the importance of a conserved interface. Structure 2024; 32:168-176.e2. [PMID: 38101402 DOI: 10.1016/j.str.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/24/2023] [Accepted: 11/20/2023] [Indexed: 12/17/2023]
Abstract
ATP-sensitive potassium channels (KATP) are inhibited by ATP but activated by Mg-ADP, coupling the intracellular ATP/ADP ratio to the potassium conductance of the plasma membrane. Although there has been progress in determining the structure of KATP, the functional significance of the domain-domain interface in the gating properties of KATP channels remains incompletely understood. In this study, we define the structure of KATP as two modules: KATPcore and SURABC. Based on this model, we identified two functionally important interfaces between these two modules, namely interface I and interface II. Further structure-guided mutagenesis experiments indicate that destabilizing interface II by deleting ECL3 on the SUR1 subunit impairs KNtp-independent Mg-ADP activation, demonstrating the essential role of intramolecular interactions between KATPcore and SURABC in Mg-ADP activation. Additionally, interface II is functionally conserved between SUR1 and SUR2, and the hydrophobic residue F351 on ECL3 of SUR1 is crucial for maintaining the stability of this interface.
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Affiliation(s)
- Yaxiong Yang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, Beijing 100871, China; Peking-Tsinghua Center for Life Sciences, Peking University, Beijing 100871, China; National Biomedical Imaging Center, Peking University, Beijing 100871, China.
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15
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Mustafa AM, Shaheen AM, Zaki HF, Rabie MA. Nicorandil and carvedilol mitigates motor deficits in experimental autoimmune encephalomyelitis-induced multiple sclerosis: Role of TLR4/TRAF6/MAPK/NF-κB signalling cascade. Int Immunopharmacol 2024; 127:111387. [PMID: 38134593 DOI: 10.1016/j.intimp.2023.111387] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 11/27/2023] [Accepted: 12/12/2023] [Indexed: 12/24/2023]
Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating neurodegenerative disease that negatively affects neurotransmission. It can be pathologically mimicked by experimental autoimmune encephalomyelitis (EAE) animal model. ATP-sensitive potassium channels (KATP) plays a crucial role in the control of neuronal damage, however their role in MS are still obscure. Additionally, Carvedilol showed a promising neuroprotective activity against several neurological disorders. Therefore, the present study aimed to investigate the potential neuroprotective effect of KATP channel opener (nicorandil) as well as α and β adrenoceptor antagonist (Carvedilol) against EAE induced neurodegeneration in mice. Mice was treated with nicorandil (6 mg/kg/day; p.o.) and carvedilol (10 mg/kg/day; p.o.) for 14 days. Nicorandil and carvedilol showed improvement in clinical scoring, behaviour and motor coordination as established by histopathological investigation and immunohistochemical detection of MBP. Furthermore, both treatments downregulated the protein expression of TLR4/ MYD88/TRAF6 signalling cascade with downstream inhibition of (pT183/Y185)-JNK/p38 (pT180/Y182)-MAPK axis leading to reduction of neuroinflammatory status, as witnessed by reduction of NF-κB, TNF-α, IL-1β and IL-6 contents. Moreover, nicorandil and carvedilol attenuated oxidative damage by increasing Nrf2 content and SOD activity together with reduction of MDA content. In addition, an immunomodulating effect via inhibiting the gene expression of CD4, TGF-β, and IL-17 as well as TGF-β, IL-17, and IL-23 contents along with anti-apoptotic effect by decreasing Bax protein expression and Caspase-3 content and increasing Bcl-2 protein expression was observed with nicorandil and carvedilol treatments. In conclusion, nicorandil and carvedilol exerted a neuroprotective activity against EAE induced neuronal loss via inhibition of TLR4/MYD88/TRAF6/JNK/p38-MAPK axis besides antioxidant and anti-apoptotic effects.
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Affiliation(s)
- Aya M Mustafa
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo, Egypt
| | - Aya M Shaheen
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Egyptian Russian University, Cairo, Egypt
| | - Hala F Zaki
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Mostafa A Rabie
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt.
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16
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Bothe MS, Kohl T, Felmy F, Gallant J, Chagnaud BP. Timing and precision of rattlesnake spinal motoneurons are determined by the KV7 2/3 potassium channel. Curr Biol 2024; 34:286-297.e5. [PMID: 38157862 DOI: 10.1016/j.cub.2023.11.062] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 10/11/2023] [Accepted: 11/29/2023] [Indexed: 01/03/2024]
Abstract
The evolution of novel motor behaviors requires modifications in the central pattern generators (CPGs) controlling muscle activity. How such changes gradually lead to novel behaviors remains enigmatic due to the long time course of evolution. Rattlesnakes provide a unique opportunity to investigate how a locomotor CPG was evolutionarily modified to generate a novel behavior-in this case, acoustic signaling. We show that motoneurons (MNs) in the body and tail spinal cord of rattlesnakes possess fundamentally different physiological characteristics, which allow MNs in the tail to integrate and transmit CPG output for controlling superfast muscles with high temporal precision. Using patch-clamp electrophysiology, we demonstrate that these differences in locomotor and rattle MNs are mainly determined by KV72/3 potassium channels. However, although KV72/3 exerted a significantly different influence on locomotor and rattle MN physiology, single-cell RNA-seq unexpectedly did not reveal any differences in KV72/3 channels' expression. VIDEO ABSTRACT.
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Affiliation(s)
| | - Tobias Kohl
- TUM School of Life Science, Technical University of Munich, 85354 Munich, Germany
| | - Felix Felmy
- Institute of Zoology, University of Veterinary Medicine Hannover, 30559 Hannover, Germany
| | - Jason Gallant
- Department of Integrative Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Boris P Chagnaud
- Institute of Biology, University of Graz, 8010 Graz, Austria; Department of Biology II, Ludwig-Maximilians-University Munich, 82152 Planegg-Martinsried, Germany
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17
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Driggers CM, Kuo YY, Zhu P, ElSheikh A, Shyng SL. Structure of an open K ATP channel reveals tandem PIP 2 binding sites mediating the Kir6.2 and SUR1 regulatory interface. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.01.551546. [PMID: 37577494 PMCID: PMC10418277 DOI: 10.1101/2023.08.01.551546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
ATP-sensitive potassium (K ATP ) channels, composed of four pore-lining Kir6.2 subunits and four regulatory sulfonylurea receptor 1 (SUR1) subunits, control insulin secretion in pancreatic β-cells. K ATP channel opening is stimulated by PIP 2 and inhibited by ATP. Mutations that increase channel opening by PIP 2 reduce ATP inhibition and cause neonatal diabetes. Although considerable evidence has indicated PIP 2 in K ATP channel function, previously solved open-channel structures have lacked bound PIP 2 , and mechanisms by which PIP 2 regulates K ATP channels remain unresolved. Here, we report the cryoEM structure of a K ATP channel harboring the neonatal diabetes mutation Kir6.2-Q52R, bound to natural C18:0/C20:4 long-chain PIP 2 in an open conformation. The structure reveals two adjacent PIP 2 molecules between SUR1 and Kir6.2. The first PIP 2 binding site is conserved among PIP 2 -gated Kir channels. The second site forms uniquely in K ATP at the interface of Kir6.2 and SUR1. Functional studies demonstrate both binding sites determine channel activity. Kir6.2 pore opening is associated with a twist of the Kir6.2 cytoplasmic domain and a rotation of the N-terminal transmembrane domain of SUR1, which widens the inhibitory ATP binding pocket to disfavor ATP binding. The open conformation is particularly stabilized by the Kir6.2-Q52R residue through cation-π bonding with SUR1-W51. Together, these results uncover the cooperation between SUR1 and Kir6.2 in PIP 2 binding and gating, explain the antagonistic regulation of K ATP channels by PIP 2 and ATP, and provide the mechanism by which Kir6.2-Q52R stabilizes an open channel to cause neonatal diabetes.
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18
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Li Z, McComic S, Chen R, Kim WTH, Gaithuma AK, Mooney B, Macaluso KR, Mulenga A, Swale DR. ATP-sensitive inward rectifier potassium channels regulate secretion of pro-feeding salivary proteins in the lone star tick (Amblyomma americanum). Int J Biol Macromol 2023; 253:126545. [PMID: 37652342 DOI: 10.1016/j.ijbiomac.2023.126545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/02/2023]
Abstract
Understanding the physiological and molecular regulation of tick feeding is necessary for developing intervention strategies to curb disease transmission by ticks. Pharmacological activation of ATP-gated inward rectifier potassium (KATP) channels reduced fluid secretion from isolated salivary gland and blood feeding in the lone star tick, Amblyomma americanum, yet the temporal expression pattern of KATP channel proteins remained unknown. KATP channels were highly expressed in type II and III acini in off-host stage and early feeding phase ticks, yet expression was reduced in later stages of feeding. We next assessed KATP channel regulation of the secreted proteome of tick saliva. LC-MS/MS analysis identified 40 differentially secreted tick saliva proteins after exposure to KATP activators or inhibitors. Secretion of previously validated tick saliva proteins that promote tick feeding, AV422, AAS27, and AAS41 were significantly reduced by upwards of 8 log units in ticks exposed to KATP channel activators when compared to untreated ticks. Importantly, activation of KATP channels inhibited tick feeding and vice versa for KATP channel inhibitors. Data indicate KATP channels regulate tick feeding biology by controlling secretion of pro-feeding proteins that are essential during early feeding phases, which provides insights into physiological and molecular regulation of tick feeding behavior.
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Affiliation(s)
- Zhilin Li
- Department of Entomology, Louisiana State University AgCenter, Baton Rouge, LA, United States of America; Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610, USA
| | - Sarah McComic
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610, USA
| | - Rui Chen
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610, USA
| | - William Tae Heung Kim
- Department of Veterinary pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX, USA
| | - Alex Kiarie Gaithuma
- Department of Veterinary pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX, USA
| | - Brian Mooney
- Department of Biochemistry, Charles W Gehrlke Proteomics Center, University of Missouri, MO, USA
| | - Kevin R Macaluso
- Department of Microbiology and Immunology, College of Medicine, University of South Alabama, Mobile, AL, USA
| | - Albert Mulenga
- Department of Veterinary pathobiology, College of Veterinary Medicine, Texas A&M University, College Station, TX, USA
| | - Daniel R Swale
- Emerging Pathogens Institute, Department of Entomology and Nematology, University of Florida, Gainesville, FL 32610, USA.
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19
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Liu W, Mossel P, Schwach V, Slart RHJA, Luurtsema G. Cardiac PET Imaging of ATP Binding Cassette (ABC) Transporters: Opportunities and Challenges. Pharmaceuticals (Basel) 2023; 16:1715. [PMID: 38139840 PMCID: PMC10748140 DOI: 10.3390/ph16121715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/01/2023] [Accepted: 12/04/2023] [Indexed: 12/24/2023] Open
Abstract
Adenosine triphosphate binding cassette (ABC) transporters are a broad family of membrane protein complexes that use energy to transport molecules across cells and/or intracellular organelle lipid membranes. Many drugs used to treat cardiac diseases have an affinity for these transporters. Among others, P-glycoprotein (P-gp) plays an essential role in regulating drug concentrations that reach cardiac tissue and therefore contribute to cardiotoxicity. As a molecular imaging modality, positron emission tomography (PET) has emerged as a viable technique to investigate the function of P-gp in organs and tissues. Using PET imaging to evaluate cardiac P-gp function provides new insights for drug development and improves the precise use of medications. Nevertheless, information in this field is limited. In this review, we aim to examine the current applications of ABC transporter PET imaging and its tracers in the heart, with a specific emphasis on P-gp. Furthermore, the opportunities and challenges in this novel field will be discussed.
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Affiliation(s)
- Wanling Liu
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; (W.L.); (P.M.)
| | - Pascalle Mossel
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; (W.L.); (P.M.)
| | - Verena Schwach
- Department of Applied Stem Cell Technologies, TechMed Centre, University of Twente, 7500 AE Enschede, The Netherlands;
| | - Riemer H. J. A. Slart
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; (W.L.); (P.M.)
- Department of Biomedical Photonic Imaging, University of Twente, 7500 AE Enschede, The Netherlands
| | - Gert Luurtsema
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; (W.L.); (P.M.)
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Corradi J, Thompson B, Fletcher PA, Bertram R, Sherman AS, Satin LS. K ATP channel activity and slow oscillations in pancreatic beta cells are regulated by mitochondrial ATP production. J Physiol 2023; 601:5655-5667. [PMID: 37983196 PMCID: PMC10842208 DOI: 10.1113/jp284982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 10/16/2023] [Indexed: 11/22/2023] Open
Abstract
Pancreatic beta cells secrete insulin in response to plasma glucose. The ATP-sensitive potassium channel (KATP ) links glucose metabolism to islet electrical activity in these cells by responding to increased cytosolic [ATP]/[ADP]. It was recently proposed that pyruvate kinase (PK) in close proximity to beta cell KATP locally produces the ATP that inhibits KATP activity. This proposal was largely based on the observation that applying phosphoenolpyruvate (PEP) and ADP to the cytoplasmic side of excised inside-out patches inhibited KATP . To test the relative contributions of local vs. mitochondrial ATP production, we recorded KATP activity using mouse beta cells and INS-1 832/13 cells. In contrast to prior reports, we could not replicate inhibition of KATP activity by PEP + ADP. However, when the pH of the PEP solutions was not corrected for the addition of PEP, strong channel inhibition was observed as a result of the well-known action of protons to inhibit KATP . In cell-attached recordings, perifusing either a PK activator or an inhibitor had little or no effect on KATP channel closure by glucose, further suggesting that PK is not an important regulator of KATP . In contrast, addition of mitochondrial inhibitors robustly increased KATP activity. Finally, by measuring the [ATP]/[ADP] responses to imposed calcium oscillations in mouse beta cells, we found that oxidative phosphorylation could raise [ATP]/[ADP] even when ADP was at its nadir during the burst silent phase, in agreement with our mathematical model. These results indicate that ATP produced by mitochondrial oxidative phosphorylation is the primary controller of KATP in pancreatic beta cells. KEY POINTS: Phosphoenolpyruvate (PEP) plus adenosine diphosphate does not inhibit KATP activity in excised patches. PEP solutions only inhibit KATP activity if the pH is unbalanced. Modulating pyruvate kinase has minimal effects on KATP activity. Mitochondrial inhibition, in contrast, robustly potentiates KATP activity in cell-attached patches. Although the ADP level falls during the silent phase of calcium oscillations, mitochondria can still produce enough ATP via oxidative phosphorylation to close KATP . Mitochondrial oxidative phosphorylation is therefore the main source of the ATP that inhibits the KATP activity of pancreatic beta cells.
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Affiliation(s)
- Jeremías Corradi
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Benjamin Thompson
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Patrick A. Fletcher
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Richard Bertram
- Department of Mathematics and Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, Florida, USA
| | - Arthur S. Sherman
- Laboratory of Biological Modeling, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Leslie S. Satin
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, Michigan, USA
- Brehm Diabetes Research Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
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21
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Michetti C, Ferrante D, Parisi B, Ciano L, Prestigio C, Casagrande S, Martinoia S, Terranova F, Millo E, Valente P, Giovedi' S, Benfenati F, Baldelli P. Low glycemic index diet restrains epileptogenesis in a gender-specific fashion. Cell Mol Life Sci 2023; 80:356. [PMID: 37947886 PMCID: PMC10638170 DOI: 10.1007/s00018-023-04988-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Revised: 09/25/2023] [Accepted: 09/27/2023] [Indexed: 11/12/2023]
Abstract
Dietary restriction, such as low glycemic index diet (LGID), have been successfully used to treat drug-resistant epilepsy. However, if such diet could also counteract antiepileptogenesis is still unclear. Here, we investigated whether the administration of LGID during the latent pre-epileptic period, prevents or delays the appearance of the overt epileptic phenotype. To this aim, we used the Synapsin II knockout (SynIIKO) mouse, a model of temporal lobe epilepsy in which seizures manifest 2-3 months after birth, offering a temporal window in which LGID may affect epileptogenesis. Pregnant SynIIKO mice were fed with either LGID or standard diet during gestation and lactation. Both diets were maintained in weaned mice up to 5 months of age. LGID delayed the seizure onset and induced a reduction of seizures severity only in female SynIIKO mice. In parallel with the epileptic phenotype, high-density multielectrode array recordings revealed a reduction of frequency, amplitude, duration, velocity of propagation and spread of interictal events by LGID in the hippocampus of SynIIKO females, but not mutant males, confirming the gender-specific effect. ELISA-based analysis revealed that LGID increased cortico-hippocampal allopregnanolone (ALLO) levels only in females, while it was unable to affect ALLO plasma concentrations in either sex. The results indicate that the gender-specific interference of LGID with the epileptogenic process can be ascribed to a gender-specific increase in cortical ALLO, a neurosteroid known to strengthen GABAergic transmission. The study highlights the possibility of developing a personalized gender-based therapy for temporal lobe epilepsy.
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Affiliation(s)
- Caterina Michetti
- Department of Experimental Medicine, University of Genova, Genoa, Italy.
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy.
| | - Daniele Ferrante
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Barbara Parisi
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Lorenzo Ciano
- Department of Experimental Medicine, University of Genova, Genoa, Italy
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy
| | - Cosimo Prestigio
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Silvia Casagrande
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Sergio Martinoia
- Department of Informatics, Bioengineering, Robotics and System Engineering, University of Genova, Genoa, Italy
| | - Fabio Terranova
- Department of Informatics, Bioengineering, Robotics and System Engineering, University of Genova, Genoa, Italy
| | - Enrico Millo
- Department of Experimental Medicine, University of Genova, Genoa, Italy
| | - Pierluigi Valente
- Department of Experimental Medicine, University of Genova, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Silvia Giovedi'
- Department of Experimental Medicine, University of Genova, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Italian Institute of Technology, Genoa, Italy
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy
| | - Pietro Baldelli
- Department of Experimental Medicine, University of Genova, Genoa, Italy.
- IRCCS, Ospedale Policlinico San Martino, Genoa, Italy.
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22
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Kang M, Lee DM, Hyun I, Rubab N, Kim SH, Kim SW. Advances in Bioresorbable Triboelectric Nanogenerators. Chem Rev 2023; 123:11559-11618. [PMID: 37756249 PMCID: PMC10571046 DOI: 10.1021/acs.chemrev.3c00301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Indexed: 09/29/2023]
Abstract
With the growing demand for next-generation health care, the integration of electronic components into implantable medical devices (IMDs) has become a vital factor in achieving sophisticated healthcare functionalities such as electrophysiological monitoring and electroceuticals worldwide. However, these devices confront technological challenges concerning a noninvasive power supply and biosafe device removal. Addressing these challenges is crucial to ensure continuous operation and patient comfort and minimize the physical and economic burden on the patient and the healthcare system. This Review highlights the promising capabilities of bioresorbable triboelectric nanogenerators (B-TENGs) as temporary self-clearing power sources and self-powered IMDs. First, we present an overview of and progress in bioresorbable triboelectric energy harvesting devices, focusing on their working principles, materials development, and biodegradation mechanisms. Next, we examine the current state of on-demand transient implants and their biomedical applications. Finally, we address the current challenges and future perspectives of B-TENGs, aimed at expanding their technological scope and developing innovative solutions. This Review discusses advancements in materials science, chemistry, and microfabrication that can advance the scope of energy solutions available for IMDs. These innovations can potentially change the current health paradigm, contribute to enhanced longevity, and reshape the healthcare landscape soon.
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Affiliation(s)
- Minki Kang
- School
of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic
of Korea
| | - Dong-Min Lee
- School
of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon 16419, Republic
of Korea
| | - Inah Hyun
- Department
of Materials Science and Engineering, Center for Human-oriented Triboelectric
Energy Harvesting, Yonsei University, Seoul 03722, Republic of Korea
| | - Najaf Rubab
- Department
of Materials Science and Engineering, Gachon
University, Seongnam 13120, Republic
of Korea
| | - So-Hee Kim
- Department
of Materials Science and Engineering, Center for Human-oriented Triboelectric
Energy Harvesting, Yonsei University, Seoul 03722, Republic of Korea
| | - Sang-Woo Kim
- Department
of Materials Science and Engineering, Center for Human-oriented Triboelectric
Energy Harvesting, Yonsei University, Seoul 03722, Republic of Korea
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23
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Gest AMM, Lazzari-Dean JR, Ortiz G, Yaeger-Weiss SK, Boggess SC, Miller EW. A red-emitting carborhodamine for monitoring and measuring membrane potential. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.06.561080. [PMID: 37873283 PMCID: PMC10592620 DOI: 10.1101/2023.10.06.561080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2023]
Abstract
Biological membrane potentials, or voltages, are a central facet of cellular life. Optical methods to visualize cellular membrane voltages with fluorescent indicators are an attractive complement to traditional electrode-based approaches, since imaging methods can be high throughput, less invasive, and provide more spatial resolution than electrodes. Recently developed fluorescent indicators for voltage largely report changes in membrane voltage by monitoring voltage-dependent fluctuations in fluorescence intensity. However, it would be useful to be able to not only monitor changes, but also measure values of membrane potentials. This study discloses a new fluorescent indicator which can address both. We describe the synthesis of a new sulfonated tetramethyl carborhodamine fluorophore. When this carborhodamine is conjugated with an electron-rich, methoxy (-OMe) containing phenylenevinylene molecular wire, the resulting molecule, CRhOMe, is a voltage-sensitive fluorophore with red/far-red fluorescence. Using CRhOMe, changes in cellular membrane potential can be read out using fluorescence intensity or lifetime. In fluorescence intensity mode, CRhOMe tracks fast-spiking neuronal action potentials with greater signal-to-noise than state-of-the-art BeRST (another voltage-sensitive fluorophore). CRhOMe can also measure values of membrane potential. The fluorescence lifetime of CRhOMe follows a single exponential decay, substantially improving the quantification of membrane potential values using fluorescence lifetime imaging microscopy (FLIM). The combination of red-shifted excitation and emission, mono-exponential decay, and high voltage sensitivity enable fast FLIM recording of action potentials in cardiomyocytes. The ability to both monitor and measure membrane potentials with red light using CRhOMe makes it an important approach for studying biological voltages.
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Affiliation(s)
| | | | - Gloria Ortiz
- Department of Chemistry, University of California, Berkeley
| | | | | | - Evan W Miller
- Department of Chemistry, University of California, Berkeley
- Department of Molecular & Cell Biology, University of California, Berkeley
- Helen Wills Neuroscience Institute, University of California, Berkeley
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24
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Huo JY, Feng YL, Chen YT, Yang B, Zhi YT, Wang HJ, Yang HQ. Caveolin-3 negatively regulates endocytic recycling of cardiac K ATP channels. Am J Physiol Cell Physiol 2023; 325:C1106-C1118. [PMID: 37746698 DOI: 10.1152/ajpcell.00266.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2023] [Revised: 09/11/2023] [Accepted: 09/11/2023] [Indexed: 09/26/2023]
Abstract
Sarcolemmal ATP-sensitive potassium (KATP) channels play a vital role in cardioprotection. Cardiac KATP channels are enriched in caveolae and physically interact with the caveolae structural protein caveolin-3 (Cav3). Disrupting caveolae impairs the regulation of KATP channels through several signaling pathways. However, the direct functional effect of Cav3 on KATP channels is still poorly understood. Here, we used the cardiac KATP channel subtype, Kir6.2/SUR2A, and showed that Cav3 greatly reduced KATP channel surface density and current amplitude in a caveolae-independent manner. A screen of Cav3 functional domains revealed that a 25 amino acid region in the membrane attachment domain of Cav3 is the minimal effective segment (MAD1). The peptide corresponding to the MAD1 segment decreased KATP channel current in a concentration-dependent manner with an IC50 of ∼5 μM. The MAD1 segment prevented KATP channel recycling, thus decreasing KATP channel surface density and abolishing the cardioprotective effect of ischemic preconditioning. Our research identified the Cav3 MAD1 segment as a novel negative regulator of KATP channel recycling, providing pharmacological potential in the treatment of diseases with KATP channel trafficking defects.NEW & NOTEWORTHY Cardiac KATP channels physically interact with caveolin-3 in caveolae. In this study, we investigated the functional effect of caveolin-3 on KATP channel activity and identified a novel segment (MAD1) in the C-terminus domain of Caveolin-3 that negatively regulates KATP channel surface density and current amplitude by impairing KATP channel recycling. The peptide corresponding to the MAD1 segment abolished the cardioprotective effect of ischemic preconditioning.
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Affiliation(s)
- Jian-Yi Huo
- Cyrus Tang Medical Institute, Soochow University, Suzhou, China
| | - Yu-Long Feng
- Cyrus Tang Medical Institute, Soochow University, Suzhou, China
| | - Yue-Tong Chen
- Cyrus Tang Medical Institute, Soochow University, Suzhou, China
| | - Bo Yang
- Cyrus Tang Medical Institute, Soochow University, Suzhou, China
| | - Ya-Ting Zhi
- Cyrus Tang Medical Institute, Soochow University, Suzhou, China
| | - Hao-Jie Wang
- Cyrus Tang Medical Institute, Soochow University, Suzhou, China
| | - Hua-Qian Yang
- Cyrus Tang Medical Institute, Soochow University, Suzhou, China
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25
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Gao J, McClenaghan C, Matreyek KA, Grange DK, Nichols CG. Rapid Characterization of the Functional and Pharmacological Consequences of Cantú Syndrome K ATP Channel Mutations in Intact Cells. J Pharmacol Exp Ther 2023; 386:298-309. [PMID: 37527933 PMCID: PMC10449099 DOI: 10.1124/jpet.123.001659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/10/2023] [Accepted: 06/01/2023] [Indexed: 08/03/2023] Open
Abstract
Gain-of-function of KATP channels, resulting from mutations in either KCNJ8 (encoding inward rectifier sub-family 6 [Kir6.1]) or ABCC9 (encoding sulphonylurea receptor [SUR2]), cause Cantú syndrome (CS), a channelopathy characterized by excess hair growth, coarse facial appearance, cardiomegaly, and lymphedema. Here, we established a pipeline for rapid analysis of CS mutation consequences in Landing pad HEK 293 cell lines stably expressing wild type (WT) and mutant human Kir6.1 and SUR2B. Thallium-influx and cell membrane potential, reported by fluorescent Tl-sensitive Fluozin-2 and voltage-sensitive bis-(1,3-dibutylbarbituric acid)trimethine oxonol (DiBAC4(3)) dyes, respectively, were used to assess channel activity. In the Tl-influx assay, CS-associated Kir6.1 mutations increased sensitivity to the ATP-sensitive potassium (KATP) channel activator, pinacidil, but there was strikingly little effect of pinacidil for any SUR2B mutations, reflecting unexpected differences in the molecular mechanisms of Kir6.1 versus SUR2B mutations. Compared with the Tl-influx assay, the DiBAC4(3) assay presents more significant signal changes in response to subtle KATP channel activity changes, and all CS mutants (both Kir6.1 and SUR2B), but not WT channels, caused marked hyperpolarization, demonstrating that all mutants were activated under ambient conditions in intact cells. Most SUR2 CS mutations were markedly inhibited by <100 nM glibenclamide, but sensitivity to inhibition by glibenclamide, repaglinide, and PNU37883A was markedly reduced for Kir6.1 CS mutations. Understanding functional consequences of mutations can help with disease diagnosis and treatment. The analysis pipeline we have developed has the potential to rapidly identify mutational consequences, aiding future CS diagnosis, drug discovery, and individualization of treatment. SIGNIFICANCE STATEMENT: We have developed new fluorescence-based assays of channel activities and drug sensitivities of Cantú syndrome (CS) mutations in human Kir6.1/SUR2B-dependent KATP channels, showing that Kir6.1 mutations increase sensitivity to potassium channel openers, while SUR2B mutations markedly reduce K channel opener (KCO) sensitivity. However, both Kir6.1 and SUR2B CS mutations are both more hyperpolarized than WT cells under basal conditions, confirming pathophysiologically relevant gain-of-function, validating DiBAC4(3) fluorescence to characterize hyperpolarization induced by KATP channel activity under basal, non KCO-activated conditions.
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Affiliation(s)
- Jian Gao
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Conor McClenaghan
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Kenneth A Matreyek
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Dorothy K Grange
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
| | - Colin G Nichols
- Department of Cell Biology and Physiology (J.G., C.M.C., C.G.N.), Center for the Investigation of Membrane Excitability Diseases (J.G., C.M.C., D.K.G., C.G.N.), and Division of Genetics and Genomic Medicine, Department of Pediatrics (D.K.G.), Washington University in St. Louis, St. Louis, Missouri; and Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, Ohio (K.A.M.)
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26
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Criveanu D, Bergqvist CA, Larhammar D, Walczewska-Szewc K. Identification of a new Kir6 potassium channel and comparison of properties of Kir6 subtypes by structural modelling and molecular dynamics. Int J Biol Macromol 2023; 247:125771. [PMID: 37433419 DOI: 10.1016/j.ijbiomac.2023.125771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 05/25/2023] [Accepted: 07/07/2023] [Indexed: 07/13/2023]
Abstract
ATP-sensitive potassium ion channels (KATP) are transmembrane proteins that modulate insulin release and muscle contraction. KATP channels are composed of two types of subunit, Kir6 and SUR, which exist in two and three isoforms respectively with different tissue distribution. In this work, we identify a previously undescribed ancestral vertebrate gene encoding a Kir6-related protein that we have named Kir6.3, which may not have a SUR binding partner, unlike the other two Kir6 proteins. Whereas Kir6.3 was lost in amniotes including mammals, it is still present in several early-diverging vertebrate lineages such as frogs, coelacanth, and rayfinned fishes. Molecular dynamics (MD) simulations using homology models of Kir6.1, Kir6.2, and Kir6.3 from the coelacanth Latimeria chalumnae showed that the three proteins exhibit subtle differences in their dynamics. Steered MD simulations of Kir6-SUR pairs suggest that Kir6.3 has a lower binding affinity for the SUR proteins than either Kir6.1 or Kir6.2. As we found no additional SUR gene in the genomes of the species that have Kir6.3, it most likely forms a lone tetramer. These findings invite studies of the tissue distribution of Kir6.3 in relation to the other Kir6 as well as SUR proteins to determine the functional roles of Kir6.3.
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Affiliation(s)
- Dan Criveanu
- School of Chemistry, University of Nottingham, Nottingham NG7 2RD, UK
| | - Christina A Bergqvist
- Department of Medical Cell Biology, Science for Life Laboratory, Biomedical Center Box 571, Uppsala University, SE-75123 Uppsala, Sweden
| | - Dan Larhammar
- Department of Medical Cell Biology, Science for Life Laboratory, Biomedical Center Box 571, Uppsala University, SE-75123 Uppsala, Sweden
| | - Katarzyna Walczewska-Szewc
- Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University in Toruń, ul. Grudziądzka 5, 87-100 Toruń, Poland.
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27
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Silvestro M, Iannone LF, Orologio I, Tessitore A, Tedeschi G, Geppetti P, Russo A. Migraine Treatment: Towards New Pharmacological Targets. Int J Mol Sci 2023; 24:12268. [PMID: 37569648 PMCID: PMC10418850 DOI: 10.3390/ijms241512268] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/13/2023] Open
Abstract
Migraine is a debilitating neurological condition affecting millions of people worldwide. Until a few years ago, preventive migraine treatments were based on molecules with pleiotropic targets, developed for other indications, and discovered by serendipity to be effective in migraine prevention, although often burdened by tolerability issues leading to low adherence. However, the progresses in unravelling the migraine pathophysiology allowed identifying novel putative targets as calcitonin gene-related peptide (CGRP). Nevertheless, despite the revolution brought by CGRP monoclonal antibodies and gepants, a significant percentage of patients still remains burdened by an unsatisfactory response, suggesting that other pathways may play a critical role, with an extent of involvement varying among different migraine patients. Specifically, neuropeptides of the CGRP family, such as adrenomedullin and amylin; molecules of the secretin family, such as pituitary adenylate cyclase-activating peptide (PACAP) and vasoactive intestinal peptide (VIP); receptors, such as transient receptor potential (TRP) channels; intracellular downstream determinants, such as potassium channels, but also the opioid system and the purinergic pathway, have been suggested to be involved in migraine pathophysiology. The present review provides an overview of these pathways, highlighting, based on preclinical and clinical evidence, as well as provocative studies, their potential role as future targets for migraine preventive treatment.
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Affiliation(s)
- Marcello Silvestro
- Headache Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (I.O.); (A.T.); (G.T.)
- Advanced MRI Neuroimaging Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy;
| | - Luigi Francesco Iannone
- Headache Centre and Clinical Pharmacology Unit, Careggi University Hospital Florence, 50134 Florence, Italy; (L.F.I.); (P.G.)
| | - Ilaria Orologio
- Headache Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (I.O.); (A.T.); (G.T.)
| | - Alessandro Tessitore
- Headache Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (I.O.); (A.T.); (G.T.)
- Advanced MRI Neuroimaging Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy;
| | - Gioacchino Tedeschi
- Headache Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy; (I.O.); (A.T.); (G.T.)
- Advanced MRI Neuroimaging Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy;
| | - Pierangelo Geppetti
- Headache Centre and Clinical Pharmacology Unit, Careggi University Hospital Florence, 50134 Florence, Italy; (L.F.I.); (P.G.)
| | - Antonio Russo
- Advanced MRI Neuroimaging Centre, Department of Advanced Medical and Surgical Sciences, University of Campania “Luigi Vanvitelli”, 80138 Naples, Italy;
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28
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Stevanović KS, Čepkenović B, Križak S, Pajić T, Todorović NV, Živić MŽ. ATP modulation of osmotically activated anionic current in the membrane of Phycomyces blakesleeanus sporangiophore. Sci Rep 2023; 13:11897. [PMID: 37488205 PMCID: PMC10366193 DOI: 10.1038/s41598-023-39021-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/19/2023] [Indexed: 07/26/2023] Open
Abstract
Ion channels are vital components of filamentous fungi signaling in communication with their environment. We exploited the ability of the apical region of growing sporangiophores of Phycomyces blakesleeanus to form membrane-enveloped cytoplasmic droplets (CDs), to examine ion currents in the filamentous fungi native plasma membrane. In hypoosmotic conditions, the dominant current in the CDs is ORIC, an osmotically activated, anionic, outwardly rectified, fast inactivating instantaneous current that we have previously characterized. Here, we examined the effect of ATP on ORIC. We show that CDs contain active mitochondria, and that respiration inhibition by azide accelerates ORIC inactivation. ATP, added intracellularly, reduced ORIC run-down and shifted the voltage dependence of inactivation toward depolarized potentials, in a manner that did not require hydrolysis. Notably, ATP led to slowing down of ORIC inactivation, as evidenced by an increased time constant of inactivation, τin, and slower decline of τin during prolonged recordings. Flavonoids (genistein and quercetin) had the effect on ORIC opposite to ATP, acting as current inhibitors, possibly by disrupting the stabilizing effect of ATP on ORIC. The integration of osmotic sensing with ATP dependence of the anionic current, typical of vertebrate cells, is described here for the first time in filamentous fungi.
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Affiliation(s)
- Katarina S Stevanović
- Faculty of Biology, Institute of Physiology and Biochemistry, University of Belgrade, Studentski Trg 16, Belgrade, 11158, Serbia
| | - Bogdana Čepkenović
- Faculty of Biology, Institute of Physiology and Biochemistry, University of Belgrade, Studentski Trg 16, Belgrade, 11158, Serbia
| | - Strahinja Križak
- Institute of Multidisciplinary Research, University of Belgrade, Kneza Višeslava 1, Belgrade, 11030, Serbia
| | - Tanja Pajić
- Faculty of Biology, Institute of Physiology and Biochemistry, University of Belgrade, Studentski Trg 16, Belgrade, 11158, Serbia
| | - Nataša V Todorović
- Institute for Biological Research "Siniša Stanković", University of Belgrade, National Institute of the Republic of Serbia, Bulevar Despota Stefana 142, Belgrade, 11000, Serbia.
| | - Miroslav Ž Živić
- Faculty of Biology, Institute of Physiology and Biochemistry, University of Belgrade, Studentski Trg 16, Belgrade, 11158, Serbia
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29
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Ding D, Hou T, Wei M, Wu JX, Chen L. The inhibition mechanism of the SUR2A-containing K ATP channel by a regulatory helix. Nat Commun 2023; 14:3608. [PMID: 37330603 PMCID: PMC10276813 DOI: 10.1038/s41467-023-39379-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 06/10/2023] [Indexed: 06/19/2023] Open
Abstract
KATP channels are metabolic sensors for intracellular ATP/ADP ratios, play essential roles in many physiological processes, and are implicated in a spectrum of pathological conditions. SUR2A-containing KATP channels differ from other subtypes in their sensitivity to Mg-ADP activation. However, the underlying structural mechanism remains poorly understood. Here we present a series of cryo-EM structures of SUR2A in the presence of different combinations of Mg-nucleotides and the allosteric inhibitor repaglinide. These structures uncover regulatory helix (R helix) on the NBD1-TMD2 linker, which wedges between NBD1 and NBD2. R helix stabilizes SUR2A in the NBD-separated conformation to inhibit channel activation. The competitive binding of Mg-ADP with Mg-ATP to NBD2 mobilizes the R helix to relieve such inhibition, allowing channel activation. The structures of SUR2B in similar conditions suggest that the C-terminal 42 residues of SUR2B enhance the structural dynamics of NBD2 and facilitate the dissociation of the R helix and the binding of Mg-ADP to NBD2, promoting NBD dimerization and subsequent channel activation.
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Affiliation(s)
- Dian Ding
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Tianyi Hou
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Miao Wei
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Jing-Xiang Wu
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China.
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China.
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30
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Gisladottir RS, Helgason A, Halldorsson BV, Helgason H, Borsky M, Chien YR, Gudnason J, Gudjonsson SA, Moisik S, Dediu D, Thorleifsson G, Tragante V, Bustamante M, Jonsdottir GA, Stefansdottir L, Rutsdottir G, Magnusson SH, Hardarson M, Ferkingstad E, Halldorsson GH, Rognvaldsson S, Skuladottir A, Ivarsdottir EV, Norddahl G, Thorgeirsson G, Jonsdottir I, Ulfarsson MO, Holm H, Stefansson H, Thorsteinsdottir U, Gudbjartsson DF, Sulem P, Stefansson K. Sequence variants affecting voice pitch in humans. SCIENCE ADVANCES 2023; 9:eabq2969. [PMID: 37294764 PMCID: PMC10256171 DOI: 10.1126/sciadv.abq2969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Accepted: 05/04/2023] [Indexed: 06/11/2023]
Abstract
The genetic basis of the human vocal system is largely unknown, as are the sequence variants that give rise to individual differences in voice and speech. Here, we couple data on diversity in the sequence of the genome with voice and vowel acoustics in speech recordings from 12,901 Icelanders. We show how voice pitch and vowel acoustics vary across the life span and correlate with anthropometric, physiological, and cognitive traits. We found that voice pitch and vowel acoustics have a heritable component and discovered correlated common variants in ABCC9 that associate with voice pitch. The ABCC9 variants also associate with adrenal gene expression and cardiovascular traits. By showing that voice and vowel acoustics are influenced by genetics, we have taken important steps toward understanding the genetics and evolution of the human vocal system.
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Affiliation(s)
- Rosa S. Gisladottir
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Department of Icelandic and Comparative Cultural Studies, University of Iceland, Saemundargata 2, 102 Reykjavik, Iceland
| | - Agnar Helgason
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Department of Anthropology, University of Iceland, Saemundargata 10, 102 Reykjavik, Iceland
| | - Bjarni V. Halldorsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | - Hannes Helgason
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | - Michal Borsky
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | - Yu-Ren Chien
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | - Jon Gudnason
- Department of Engineering, Reykjavik University, Menntavegur 1, 101 Reykjavik, Iceland
| | | | - Scott Moisik
- Division of Linguistics and Multilingual Studies, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore
| | - Dan Dediu
- Department of Catalan Philology and General Linguistics, University of Barcelona, Gran Via 585, Barcelona 08007, Spain
- University of Barcelona Institute for Complex Systems (UBICS), Martí Franquès 1, Barcelona 08028, Spain
- Catalan Institute for Research and Advanced Studies (ICREA), Passeig Lluís Companys 23, Barcelona 08010, Spain
| | | | | | | | | | | | | | | | | | - Egil Ferkingstad
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | - Gisli H. Halldorsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland
| | | | | | | | | | - Gudmundur Thorgeirsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
| | - Ingileif Jonsdottir
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
| | - Magnus O. Ulfarsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland
| | - Hilma Holm
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | | | - Unnur Thorsteinsdottir
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
| | - Daniel F. Gudbjartsson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- School of Engineering and Natural Sciences, University of Iceland, Dunhagi 5, 107 Reykjavik, Iceland
| | - Patrick Sulem
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
| | - Kari Stefansson
- deCODE Genetics/Amgen Inc., Sturlugata 8, 101 Reykjavik, Iceland
- Faculty of Medicine, University of Iceland, Vatnsmyrarvegur 16, 101 Reykjavik, Iceland
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31
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McClenaghan C, Mukadam MA, Roeglin J, Tryon RC, Grabner M, Dayal A, Meyer GA, Nichols CG. Skeletal muscle delimited myopathy and verapamil toxicity in SUR2 mutant mouse models of AIMS. EMBO Mol Med 2023; 15:e16883. [PMID: 37154692 PMCID: PMC10245035 DOI: 10.15252/emmm.202216883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 04/10/2023] [Accepted: 04/17/2023] [Indexed: 05/10/2023] Open
Abstract
ABCC9-related intellectual disability and myopathy syndrome (AIMS) arises from loss-of-function (LoF) mutations in the ABCC9 gene, which encodes the SUR2 subunit of ATP-sensitive potassium (KATP ) channels. KATP channels are found throughout the cardiovascular system and skeletal muscle and couple cellular metabolism to excitability. AIMS individuals show fatigability, muscle spasms, and cardiac dysfunction. We found reduced exercise performance in mouse models of AIMS harboring premature stop codons in ABCC9. Given the roles of KATP channels in all muscles, we sought to determine how myopathy arises using tissue-selective suppression of KATP and found that LoF in skeletal muscle, specifically, underlies myopathy. In isolated muscle, SUR2 LoF results in abnormal generation of unstimulated forces, potentially explaining painful spasms in AIMS. We sought to determine whether excessive Ca2+ influx through CaV 1.1 channels was responsible for myopathology but found that the Ca2+ channel blocker verapamil unexpectedly resulted in premature death of AIMS mice and that rendering CaV 1.1 channels nonpermeable by mutation failed to reverse pathology; results which caution against the use of calcium channel blockers in AIMS.
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Affiliation(s)
- Conor McClenaghan
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
- Center for Advanced Biotechnology and Medicine, and Departments of Pharmacology and Medicine, Robert Wood Johnson Medical SchoolRutgers UniversityPiscatawayNJUSA
| | - Maya A Mukadam
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Jacob Roeglin
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Robert C Tryon
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
| | - Manfred Grabner
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Anamika Dayal
- Department of PharmacologyMedical University of InnsbruckInnsbruckAustria
| | - Gretchen A Meyer
- Program in Physical Therapy, Departments of Orthopaedic Surgery, Neurology and Biomedical EngineeringWashington University School of MedicineSt. LouisMOUSA
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases, and Department of Cell Biology and PhysiologyWashington University School of MedicineSt. LouisMOUSA
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32
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Wu X, Xu M, Geng M, Chen S, Little PJ, Xu S, Weng J. Targeting protein modifications in metabolic diseases: molecular mechanisms and targeted therapies. Signal Transduct Target Ther 2023; 8:220. [PMID: 37244925 DOI: 10.1038/s41392-023-01439-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/01/2023] [Accepted: 04/06/2023] [Indexed: 05/29/2023] Open
Abstract
The ever-increasing prevalence of noncommunicable diseases (NCDs) represents a major public health burden worldwide. The most common form of NCD is metabolic diseases, which affect people of all ages and usually manifest their pathobiology through life-threatening cardiovascular complications. A comprehensive understanding of the pathobiology of metabolic diseases will generate novel targets for improved therapies across the common metabolic spectrum. Protein posttranslational modification (PTM) is an important term that refers to biochemical modification of specific amino acid residues in target proteins, which immensely increases the functional diversity of the proteome. The range of PTMs includes phosphorylation, acetylation, methylation, ubiquitination, SUMOylation, neddylation, glycosylation, palmitoylation, myristoylation, prenylation, cholesterylation, glutathionylation, S-nitrosylation, sulfhydration, citrullination, ADP ribosylation, and several novel PTMs. Here, we offer a comprehensive review of PTMs and their roles in common metabolic diseases and pathological consequences, including diabetes, obesity, fatty liver diseases, hyperlipidemia, and atherosclerosis. Building upon this framework, we afford a through description of proteins and pathways involved in metabolic diseases by focusing on PTM-based protein modifications, showcase the pharmaceutical intervention of PTMs in preclinical studies and clinical trials, and offer future perspectives. Fundamental research defining the mechanisms whereby PTMs of proteins regulate metabolic diseases will open new avenues for therapeutic intervention.
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Affiliation(s)
- Xiumei Wu
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-sen University, 510000, Guangzhou, China
| | - Mengyun Xu
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Mengya Geng
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Shuo Chen
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Peter J Little
- School of Pharmacy, University of Queensland, Pharmacy Australia Centre of Excellence, Woolloongabba, QLD, 4102, Australia
- Sunshine Coast Health Institute and School of Health and Behavioural Sciences, University of the Sunshine Coast, Birtinya, QLD, 4575, Australia
| | - Suowen Xu
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China
| | - Jianping Weng
- Department of Endocrinology, Institute of Endocrine and Metabolic Diseases, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Clinical Research Hospital of Chinese Academy of Sciences (Hefei), University of Science and Technology of China, Hefei, Anhui, 230001, China.
- Department of Endocrinology and Metabolism, Guangdong Provincial Key Laboratory of Diabetology, The Third Affiliated Hospital of Sun Yat-sen University, 510000, Guangzhou, China.
- Bengbu Medical College, Bengbu, 233000, China.
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33
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Strutynskyi R, Strutynska N, Mys L, Goshovska Y, Korkach Y, Fedichkina R, Okhai I, Strutynskyi V, Sagach V. Glutathione Upregulates the Expression of K ATP Channels and Vasorelaxation Responses and Inhibits mPTP Opening and Oxidative Stress in the Heart Mitochondria of Old Rats. BIOMED RESEARCH INTERNATIONAL 2023; 2023:3562847. [PMID: 37265475 PMCID: PMC10232108 DOI: 10.1155/2023/3562847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 04/25/2023] [Accepted: 05/13/2023] [Indexed: 06/03/2023]
Abstract
Background In the present work, we investigated the effect of exogenous glutathione in old rats on the expression of ATP-sensitive potassium (KATP) channels, the mitochondrial permeability transition pore (mPTP) opening in the heart, and the vasorelaxation responses of isolated aortic rings to activation of KATP channels. Methods Experiments were performed on adult (6 months) and old (24 months) male Wistar rats, which were divided into three groups: adult, old, and glutathione-treated old rats. Glutathione was injected intraperitoneally at a dose of 52 mg/kg 1 hour before the studies. The mRNA expression of KATP channels was determined using reverse transcription and real-time polymerase chain reaction analysis. The effect of glutathione administration on mPTP opening, relaxation responses of isolated aortic rings, and oxidative stress markers was studied. Results It was shown that the expression levels of Kir6.1, Kir6.2, and SUR1 subunits of KATP channels and levels of reduced glutathione were significantly increased in glutathione-treated old rats (by 8.3, 2.8, 13.1, and 1.5-fold, respectively), whereas the levels of oxidative stress markers (hydrogen peroxide, diene conjugates, malondialdehyde, and rate of superoxide generation) in heart mitochondria and mPTP opening were significantly reduced. Relaxation of aortic rings was significantly increased in response to the actions of KATP channel openers flocalin and pinacidil in glutathione-treated animals, which was prevented by glibenclamide. Conclusions Thus, the administration of exogenous glutathione to old rats resulted in a significant increase in the expression levels of the Kir6.1, Kir6.2, and SUR1 subunits of KATP channels and a decrease in oxidative stress. This was accompanied by inhibition of mPTP opening and enhancement of vasorelaxation responses to activation of KATP channels.
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Affiliation(s)
- Ruslan Strutynskyi
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Nataliіa Strutynska
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Lidiia Mys
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Yulia Goshovska
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Yuliia Korkach
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Raisa Fedichkina
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Iryna Okhai
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Vladyslav Strutynskyi
- Department of Immunophysiology, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
| | - Vadym Sagach
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, 4, Bogomoletz Str., Kyiv 01024, Ukraine
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34
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Chen B, Wei S, Low SW, Poore CP, Lee ATH, Nilius B, Liao P. TRPM4 Blocking Antibody Protects Cerebral Vasculature in Delayed Stroke Reperfusion. Biomedicines 2023; 11:biomedicines11051480. [PMID: 37239151 DOI: 10.3390/biomedicines11051480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 05/15/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
Reperfusion therapy for acute ischemic stroke aims to restore the blood flow of occluded blood vessels. However, successful recanalization is often associated with disruption of the blood-brain barrier, leading to reperfusion injury. Delayed recanalization increases the risk of severe reperfusion injury, including severe cerebral edema and hemorrhagic transformation. The TRPM4-blocking antibody M4P has been shown to alleviate reperfusion injury and improve functional outcomes in animal models of early stroke reperfusion. In this study, we examined the role of M4P in a clinically relevant rat model of delayed stroke reperfusion in which the left middle cerebral artery was occluded for 7 h. To mimic the clinical scenario, M4P or control IgG was administered 1 h before recanalization. Immunostaining showed that M4P treatment improved vascular morphology after stroke. Evans blue extravasation demonstrated attenuated vascular leakage following M4P treatment. With better vascular integrity, cerebral perfusion was improved, leading to a reduction of infarct volume and animal mortality rate. Functional outcome was evaluated by the Rotarod test. As more animals with severe injuries died during the test in the control IgG group, we observed no difference in functional outcomes in the surviving animals. In conclusion, we identified the potential of TRPM4 blocking antibody M4P to ameliorate vascular injury during delayed stroke reperfusion. If combined with reperfusion therapy, M4P has the potential to improve current stroke management.
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Affiliation(s)
- Bo Chen
- Calcium Signalling Laboratory, Department of Research, National Neuroscience Institute, Singapore 308433, Singapore
| | - Shunhui Wei
- Calcium Signalling Laboratory, Department of Research, National Neuroscience Institute, Singapore 308433, Singapore
| | - See Wee Low
- Calcium Signalling Laboratory, Department of Research, National Neuroscience Institute, Singapore 308433, Singapore
| | - Charlene Priscilla Poore
- Calcium Signalling Laboratory, Department of Research, National Neuroscience Institute, Singapore 308433, Singapore
| | - Andy Thiam-Huat Lee
- Health and Social Sciences, Singapore Institute of Technology, Singapore 138683, Singapore
| | - Bernd Nilius
- Department of Cellular and Molecular Medicine, KU Leuven, 3000 Leuven, Belgium
| | - Ping Liao
- Calcium Signalling Laboratory, Department of Research, National Neuroscience Institute, Singapore 308433, Singapore
- Health and Social Sciences, Singapore Institute of Technology, Singapore 138683, Singapore
- Neuroscience Academic Clinical Programme, Duke-NUS Medical School, Singapore 169857, Singapore
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35
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Grizzanti J, Moritz WR, Pait MC, Stanley M, Kaye SD, Carroll CM, Constantino NJ, Deitelzweig LJ, Snipes JA, Kellar D, Caesar EE, Pettit-Mee RJ, Day SM, Sens JP, Nicol NI, Dhillon J, Remedi MS, Kiraly DD, Karch CM, Nichols CG, Holtzman DM, Macauley SL. KATP channels are necessary for glucose-dependent increases in amyloid-β and Alzheimer's disease-related pathology. JCI Insight 2023; 8:e162454. [PMID: 37129980 PMCID: PMC10386887 DOI: 10.1172/jci.insight.162454] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 04/18/2023] [Indexed: 05/03/2023] Open
Abstract
Elevated blood glucose levels, or hyperglycemia, can increase brain excitability and amyloid-β (Aβ) release, offering a mechanistic link between type 2 diabetes and Alzheimer's disease (AD). Since the cellular mechanisms governing this relationship are poorly understood, we explored whether ATP-sensitive potassium (KATP) channels, which couple changes in energy availability with cellular excitability, play a role in AD pathogenesis. First, we demonstrate that KATP channel subunits Kir6.2/KCNJ11 and SUR1/ABCC8 were expressed on excitatory and inhibitory neurons in the human brain, and cortical expression of KCNJ11 and ABCC8 changed with AD pathology in humans and mice. Next, we explored whether eliminating neuronal KATP channel activity uncoupled the relationship between metabolism, excitability, and Aβ pathology in a potentially novel mouse model of cerebral amyloidosis and neuronal KATP channel ablation (i.e., amyloid precursor protein [APP]/PS1 Kir6.2-/- mouse). Using both acute and chronic paradigms, we demonstrate that Kir6.2-KATP channels are metabolic sensors that regulate hyperglycemia-dependent increases in interstitial fluid levels of Aβ, amyloidogenic processing of APP, and amyloid plaque formation, which may be dependent on lactate release. These studies identify a potentially new role for Kir6.2-KATP channels in AD and suggest that pharmacological manipulation of Kir6.2-KATP channels holds therapeutic promise in reducing Aβ pathology in patients with diabetes or prediabetes.
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Affiliation(s)
- John Grizzanti
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - William R. Moritz
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - Morgan C. Pait
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Molly Stanley
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
- Department of Biology, College of Arts and Sciences, University of Vermont, Burlington, Vermont, USA
| | - Sarah D. Kaye
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Caitlin M. Carroll
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Nicholas J. Constantino
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Lily J. Deitelzweig
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - James A. Snipes
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Derek Kellar
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Emily E. Caesar
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | | | | | | | - Noelle I. Nicol
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Jasmeen Dhillon
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Maria S. Remedi
- Department of Physiology and Pharmacology and
- Department of Medicine, Division of Endocrinology, Metabolism and Lipid Research
| | | | - Celeste M. Karch
- Department of Psychiatry
- Hope Center for Neurological Disorders
- Knight Alzheimer’s Disease Research Center, Department of Neurology; and
| | - Colin G. Nichols
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
| | - David M. Holtzman
- Department of Neurology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, USA
- Hope Center for Neurological Disorders
- Knight Alzheimer’s Disease Research Center, Department of Neurology; and
| | - Shannon L. Macauley
- Department of Physiology and Pharmacology and
- Department of Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
- Alzheimer’s Disease Research Center
- Center on Diabetes, Obesity and Metabolism
- Center for Precision Medicine; and
- Cardiovascular Sciences Center, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
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36
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Tuncay E, Gando I, Huo JY, Yepuri G, Samper N, Turan B, Yang HQ, Ramasamy R, Coetzee WA. The cardioprotective role of sirtuins is mediated in part by regulating K ATP channel surface expression. Am J Physiol Cell Physiol 2023; 324:C1017-C1027. [PMID: 36878847 PMCID: PMC10110703 DOI: 10.1152/ajpcell.00459.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 02/24/2023] [Accepted: 02/27/2023] [Indexed: 03/08/2023]
Abstract
Sirtuins are NAD+-dependent deacetylases with beneficial roles in conditions relevant to human health, including metabolic disease, type II diabetes, obesity, cancer, aging, neurodegenerative diseases, and cardiac ischemia. Since ATP-sensitive K+ (KATP) channels have cardioprotective roles, we investigated whether they are regulated by sirtuins. Nicotinamide mononucleotide (NMN) was used to increase cytosolic NAD+ levels and to activate sirtuins in cell lines, isolated rat and mouse cardiomyocytes or insulin-secreting INS-1 cells. KATP channels were studied with patch clamping, biochemistry techniques, and antibody uptake experiments. NMN led to an increase in intracellular NAD+ levels and an increase in the KATP channel current, without significant changes in the unitary current amplitude or open probability. An increased surface expression was confirmed using surface biotinylation approaches. The rate of KATP channel internalization was diminished by NMN, which may be a partial explanation for the increased surface expression. We show that NMN acts via sirtuins since the increased KATP channel surface expression was prevented by blockers of SIRT1 and SIRT2 (Ex527 and AGK2) and mimicked by SIRT1 activation (SRT1720). The pathophysiological relevance of this finding was studied using a cardioprotection assay with isolated ventricular myocytes, in which NMN protected against simulated ischemia or hypoxia in a KATP channel-dependent manner. Overall, our data draw a link between intracellular NAD+, sirtuin activation, KATP channel surface expression, and cardiac protection against ischemic damage.
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Affiliation(s)
- Erkan Tuncay
- Department of Biophysics, Faculty of Medicine, Ankara University, Ankara, Turkey
| | - Ivan Gando
- Department of Pathology, New York University Grossman Medical Center, New York, New York, United States
| | - Jian-Yi Huo
- Cyrus Tang Hematology Center, Soochow University, Suzhou, People's Republic of China
| | - Gautham Yepuri
- Department of Medicine, New York University Grossman Medical Center, New York, New York, United States
| | - Natalie Samper
- Department of Pathology, New York University Grossman Medical Center, New York, New York, United States
| | - Belma Turan
- Department of Biophysics, Faculty of Medicine, Lokman Hekim University, Ankara, Turkey
| | - Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, People's Republic of China
| | - Ravichandran Ramasamy
- Department of Medicine, New York University Grossman Medical Center, New York, New York, United States
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman Medical Center, New York, New York, United States
| | - William A Coetzee
- Department of Pathology, New York University Grossman Medical Center, New York, New York, United States
- Department of Physiology & Neuroscience, New York University Grossman Medical Center, New York, New York, United States
- Department of Biochemistry and Molecular Pharmacology, New York University Grossman Medical Center, New York, New York, United States
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Davis MJ, Castorena-Gonzalez JA, Kim HJ, Li M, Remedi M, Nichols CG. Lymphatic contractile dysfunction in mouse models of Cantú Syndrome with K ATP channel gain-of-function. FUNCTION 2023; 4:zqad017. [PMID: 37214333 PMCID: PMC10194823 DOI: 10.1093/function/zqad017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 04/01/2023] [Accepted: 04/07/2023] [Indexed: 05/24/2023] Open
Abstract
Cantú Syndrome (CS) is an autosomal dominant disorder caused by gain-of-function (GoF) mutations in the Kir6.1 and SUR2 subunits of KATP channels. KATP overactivity results in a chronic reduction in arterial tone and hypotension, leading to other systemic cardiovascular complications. However, the underlying mechanism of lymphedema, developed by >50% of CS patients, is unknown. We investigated whether lymphatic contractile dysfunction occurs in mice expressing CS mutations in Kir6.1 (Kir6.1[V65M]) or SUR2 (SUR2[A478V], SUR2[R1154Q]). Pressure myograph tests of contractile function of popliteal lymphatic vessels over the physiological pressure range revealed significantly impaired contractile strength and reduced frequency of spontaneous contractions at all pressures in heterozygous Kir6.1[V65M] vessels, compared to control littermates. Contractile dysfunction of intact popliteal lymphatics in vivo was confirmed using near-infrared fluorescence microscopy. Homozygous SUR2[A478V] vessels exhibited profound contractile dysfunction ex vivo, but heterozygous SUR2[A478V] vessels showed essentially normal contractile function. However, further investigation of vessels from all three GoF mouse strains revealed significant disruption in contraction wave entrainment, decreased conduction speed and distance, multiple pacemaker sites, and reversing wave direction. Tests of 2-valve lymphatic vessels forced to pump against an adverse pressure gradient revealed that all CS-associated genotypes were essentially incapable of pumping under an imposed outflow load. Our results show that varying degrees of lymphatic contractile dysfunction occur in proportion to the degree of molecular GoF in Kir6.1 or SUR2. This is the first example of lymphatic contractile dysfunction caused by a smooth muscle ion channel mutation and potentially explains the susceptibility of CS patients to lymphedema.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia MO 65212, USA
| | | | - Hae Jin Kim
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia MO 65212, USA
| | - Min Li
- Department of Medical Pharmacology and Physiology, University of Missouri School of Medicine, Columbia MO 65212, USA
| | - Maria Remedi
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Colin G Nichols
- Center for the Investigation of Membrane Excitability Diseases, Washington University School of Medicine, St. Louis, MO 63110, USA
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110, USA
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38
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Davis MJ, Earley S, Li YS, Chien S. Vascular mechanotransduction. Physiol Rev 2023; 103:1247-1421. [PMID: 36603156 PMCID: PMC9942936 DOI: 10.1152/physrev.00053.2021] [Citation(s) in RCA: 40] [Impact Index Per Article: 40.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 09/26/2022] [Accepted: 10/04/2022] [Indexed: 01/07/2023] Open
Abstract
This review aims to survey the current state of mechanotransduction in vascular smooth muscle cells (VSMCs) and endothelial cells (ECs), including their sensing of mechanical stimuli and transduction of mechanical signals that result in the acute functional modulation and longer-term transcriptomic and epigenetic regulation of blood vessels. The mechanosensors discussed include ion channels, plasma membrane-associated structures and receptors, and junction proteins. The mechanosignaling pathways presented include the cytoskeleton, integrins, extracellular matrix, and intracellular signaling molecules. These are followed by discussions on mechanical regulation of transcriptome and epigenetics, relevance of mechanotransduction to health and disease, and interactions between VSMCs and ECs. Throughout this review, we offer suggestions for specific topics that require further understanding. In the closing section on conclusions and perspectives, we summarize what is known and point out the need to treat the vasculature as a system, including not only VSMCs and ECs but also the extracellular matrix and other types of cells such as resident macrophages and pericytes, so that we can fully understand the physiology and pathophysiology of the blood vessel as a whole, thus enhancing the comprehension, diagnosis, treatment, and prevention of vascular diseases.
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Affiliation(s)
- Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Scott Earley
- Department of Pharmacology, University of Nevada, Reno, Nevada
| | - Yi-Shuan Li
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
| | - Shu Chien
- Department of Bioengineering, University of California, San Diego, California
- Institute of Engineering in Medicine, University of California, San Diego, California
- Department of Medicine, University of California, San Diego, California
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Martin GM, Patton BL, Shyng SL. K ATP channels in focus: Progress toward a structural understanding of ligand regulation. Curr Opin Struct Biol 2023; 79:102541. [PMID: 36807078 PMCID: PMC10023423 DOI: 10.1016/j.sbi.2023.102541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/11/2022] [Accepted: 01/14/2023] [Indexed: 02/21/2023]
Abstract
KATP channels are hetero-octameric complexes of four inward rectifying potassium channels, Kir6.1 or Kir6.2, and four sulfonylurea receptors, SUR1, SUR2A, or SUR2B from the ABC transporter family. This unique combination enables KATP channels to couple intracellular ATP/ADP ratios, through gating, with membrane excitability, thus regulating a broad range of cellular activities. The prominence of KATP channels in human physiology, disease, and pharmacology has long attracted research interest. Since 2017, a steady flow of high-resolution KATP cryoEM structures has revealed complex and dynamic interactions between channel subunits and their ligands. Here, we highlight insights from recent structures that begin to provide mechanistic explanations for decades of experimental data and discuss the remaining knowledge gaps in our understanding of KATP channel regulation.
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Affiliation(s)
- Gregory M Martin
- Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, CA, 92037, USA
| | - Bruce L Patton
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, 97239, USA
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR, 97239, USA.
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40
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ElSheikh A, Shyng SL. K ATP channel mutations in congenital hyperinsulinism: Progress and challenges towards mechanism-based therapies. Front Endocrinol (Lausanne) 2023; 14:1161117. [PMID: 37056678 PMCID: PMC10086357 DOI: 10.3389/fendo.2023.1161117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 03/13/2023] [Indexed: 03/30/2023] Open
Abstract
Congenital hyperinsulinism (CHI) is the most common cause of persistent hypoglycemia in infancy/childhood and is a serious condition associated with severe recurrent attacks of hypoglycemia due to dysregulated insulin secretion. Timely diagnosis and effective treatment are crucial to prevent severe hypoglycemia that may lead to life-long neurological complications. In pancreatic β-cells, adenosine triphosphate (ATP)-sensitive K+ (KATP) channels are a central regulator of insulin secretion vital for glucose homeostasis. Genetic defects that lead to loss of expression or function of KATP channels are the most common cause of HI (KATP-HI). Much progress has been made in our understanding of the molecular genetics and pathophysiology of KATP-HI in the past decades; however, treatment remains challenging, in particular for patients with diffuse disease who do not respond to the KATP channel activator diazoxide. In this review, we discuss current approaches and limitations on the diagnosis and treatment of KATP-HI, and offer perspectives on alternative therapeutic strategies.
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Affiliation(s)
- Assmaa ElSheikh
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States
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41
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Dyhring T, Jansen-Olesen I, Christophersen P, Olesen J. Pharmacological Profiling of K ATP Channel Modulators: An Outlook for New Treatment Opportunities for Migraine. Pharmaceuticals (Basel) 2023; 16:225. [PMID: 37259373 PMCID: PMC9966414 DOI: 10.3390/ph16020225] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/28/2023] [Accepted: 01/30/2023] [Indexed: 12/23/2023] Open
Abstract
Migraine is a highly disabling pain disorder with huge socioeconomic and personal costs. It is genetically heterogenous leading to variability in response to current treatments and frequent lack of response. Thus, new treatment strategies are needed. A combination of preclinical and clinical data indicate that ATP-sensitive potassium (KATP) channel inhibitors could be novel and highly effective drugs in the treatment of migraine. The subtype Kir6.1/SUR2B is of particular interest and inhibitors specific for this cranio-vascular KATP channel subtype may qualify as future migraine drugs. Historically, different technologies and methods have been undertaken to characterize KATP channel modulators and, therefore, a head-to-head comparison of potency and selectivity between the different KATP subtypes is difficult to assess. Here, we characterize available KATP channel activators and inhibitors in fluorescence-based thallium-flux assays using HEK293 cells stably expressing human Kir6.1/SUR2B, Kir6.2/SUR1, and Kir6.2/SUR2A KATP channels. Among the openers tested, levcromakalim, Y-26763, pinacidil, P-1075, ZM226600, ZD0947, and A-278637 showed preference for the KATP channel subtype Kir6.1/SUR2B, whereas BMS-191095, NN414, and VU0071306 demonstrated preferred activation of the Kir6.2/SUR1 subtype. In the group of KATP channel blockers, only Rosiglitazone and PNU-37783A showed selective inhibition of the Kir6.1/SUR2B subtype. PNU-37783A was stopped in clinical development and Rosiglitazone has a low potency for the vascular KATP channel subtype. Therefore, development of novel selective KATP channel blockers, having a benign side effect profile, are needed to clinically prove inhibition of Kir6.1/SUR2B as an effective migraine treatment.
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Affiliation(s)
| | - Inger Jansen-Olesen
- Danish Headache Center, Department of Neurology, University of Copenhagen, 2600 Glostrup, Denmark
| | | | - Jes Olesen
- Danish Headache Center, Department of Neurology, University of Copenhagen, 2600 Glostrup, Denmark
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42
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Gao J, McClenaghan C, Christiaans I, Alders M, van Duinen K, van Haelst MM, van Haaften G, Nichols CG. Lymphedema as first clinical presentation of Cantu Syndrome: reversed phenotyping after identification of gain-of-function variant in ABCC9. Eur J Hum Genet 2023; 31:188-194. [PMID: 36336713 PMCID: PMC9905590 DOI: 10.1038/s41431-022-01210-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 08/16/2022] [Accepted: 09/30/2022] [Indexed: 11/09/2022] Open
Abstract
Cantu Syndrome (CS), [OMIM #239850] is characterized by hypertrichosis, osteochondrodysplasia, and cardiomegaly. CS is caused by gain-of-function (GOF) variants in the KCNJ8 or ABCC9 genes that encode pore-forming Kir6.1 and regulatory SUR2 subunits of ATP-sensitive potassium (KATP) channels. Many subjects with CS also present with the complication of lymphedema. A previously uncharacterized, heterozygous ABCC9 variant, p.(Leu1055_Glu1058delinsPro), termed indel1055, was identified in an individual diagnosed with idiopathic lymphedema. The variant was introduced into the equivalent position of rat SUR2A, and inside-out patches were used to characterize the KATP channels formed by Kir6.2 and WT or mutant SUR2A subunits coexpressed in Cosm6 cells. The indel1055 variant causes gain-of-function of the channel, with an increase of the IC50 for ATP inhibition compared to WT. Retrospective consideration of this individual reveals clear features of Cantu Syndrome. An additional heterozygous ABCC9 variant, p.(Ile419Thr), was identified in a second individual diagnosed with lymphedema. In this case, there were no additional features consistent with CS, and the properties of p.(Ile416Thr) (the corresponding mutation in rat SUR2A)--containing channels were not different from WT. This proof-of-principle study shows that idiopathic lymphedema may actually be a first presentation of otherwise unrecognized Cantu Syndrome, but molecular phenotyping of identified variants is necessary to confirm relevance.
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Affiliation(s)
- Jian Gao
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis, St. Louis, MO, USA
| | - Conor McClenaghan
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis, St. Louis, MO, USA
| | - Imke Christiaans
- Department of Genetics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Marielle Alders
- University of Amsterdam, Department of Human Genetics, Meibergdreef 9, Amsterdam, The Netherlands
| | - Kirsten van Duinen
- Department of Dermatology, Nij Smellinghe Hospital, Drachten, The Netherlands
| | - Mieke M van Haelst
- University of Amsterdam, Department of Human Genetics, Meibergdreef 9, Amsterdam, The Netherlands.
- Departments of Pediatrics, Amsterdam University Medical Centers, Amsterdam, The Netherlands.
- Emma Center for Personalized Medicine, Amsterdam University Medical Centers, Amsterdam, The Netherlands.
| | - Gijs van Haaften
- Department of Genetics, Center for Molecular Medicine, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Colin G Nichols
- Department of Cell Biology and Physiology and Center for the Investigation of Membrane Excitability Diseases, Washington University in St. Louis, St. Louis, MO, USA.
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43
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Nichols CG. Personalized Therapeutics for K ATP-Dependent Pathologies. Annu Rev Pharmacol Toxicol 2023; 63:541-563. [PMID: 36170658 PMCID: PMC9868118 DOI: 10.1146/annurev-pharmtox-051921-123023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Ubiquitously expressed throughout the body, ATP-sensitive potassium (KATP) channels couple cellular metabolism to electrical activity in multiple tissues; their unique assembly as four Kir6 pore-forming subunits and four sulfonylurea receptor (SUR) subunits has resulted in a large armory of selective channel opener and inhibitor drugs. The spectrum of monogenic pathologies that result from gain- or loss-of-function mutations in these channels, and the potential for therapeutic correction of these pathologies, is now clear. However, while available drugs can be effective treatments for specific pathologies, cross-reactivity with the other Kir6 or SUR subfamily members can result in drug-induced versions of each pathology and may limit therapeutic usefulness. This review discusses the background to KATP channel physiology, pathology, and pharmacology and considers the potential for more specific or effective therapeutic agents.
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Affiliation(s)
- Colin G. Nichols
- Center for the Investigation of Membrane Excitability Diseases and Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri, USA
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44
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Strutynskyi RB, Strutynska NA, Piven OO, Mys LA, Goshovska YV, Fedichkina RA, Okhai IY, Strutynskyi VR, Dosenko VE, Dobrzyn P, Sagach VF. Upregulation of ATP-Sensitive Potassium Channels as the Potential Mechanism of Cardioprotection and Vasorelaxation Under the Action of Pyridoxal-5-Phosphate in Old Rats. J Cardiovasc Pharmacol Ther 2023; 28:10742484231213175. [PMID: 37946524 DOI: 10.1177/10742484231213175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
Background: The aging process is accompanied by the weakening of the protective systems of the organism, in particular by the decrease in the expression of ATP-sensitive potassium (KATP) channels and in the synthesis of H2S. The aim of our work was to investigate the role of KATP channels in the cardioprotection induced by pyridoxal-5-phosphate (PLP) in aging. Methods: Experiments were performed on adult and old (aged 24 months) male Wistar rats, which were divided into 3 groups: adults, old, and old PLP-treated rats. PLP was administered orally once a day for 14 days at a dose of 0.7 mg/kg. The levels of mRNA expression of subunits KATP channels were determined by reverse transcription and real-time polymerase chain reaction analysis. Protein expression levels were determined by the Western blot. Cardiac tissue morphology was determined using transverse 6 μm deparaffinized sections stained with picrosirius red staining. Vasorelaxation responses of isolated aortic rings and the function of Langendorff-perfused isolated hearts during ischemia-reperfusion, H2S levels, and markers of oxidative stress were also studied. Results: Administration of PLP to old rats reduces cardiac fibrosis and improves cardiac function during ischemia-reperfusion and vasorelaxation responses to KATP channels opening. At the same time, there was a significant increase in mRNA and protein expression of SUR2 and Kir6.1 subunits of KATP channels, H2S production, and reduced markers of oxidative stress. The specific KATP channel inhibitor-glibenclamide prevented the enhancement of vasodilator responses and anti-ischemic protection in PLP-treated animals. Conclusions: We suggest that this potential therapeutic effect of PLP in old animals may be a result of increased expression of KATP channels and H2S production.
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Affiliation(s)
- Ruslan B Strutynskyi
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Nataliіa A Strutynska
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Oksana O Piven
- The Laboratory of Molecular Medical Biochemistry of Nencki, Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
- Department of Human Genetics, Institute of Molecular Biology and Genetics, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Lidiia A Mys
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Yulia V Goshovska
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Raisa A Fedichkina
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Iryna Y Okhai
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Vladyslav R Strutynskyi
- Department of Immunophysiology, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Victor E Dosenko
- Department of General and Molecular Pathophysiology, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Pawel Dobrzyn
- The Laboratory of Molecular Medical Biochemistry of Nencki, Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Vadim F Sagach
- Department of Blood Circulation, Bogomoletz Institute of Physiology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
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Qian C, Fan Y, Zong L, Miao C, Ji LL, Wan L, Jia R, Qin X, Wang Y, Wu Q, Tao XY, Hao L, Hu L, Liu WT. Opening K ATP channels induces inflammatory tolerance and prevents chronic pain. Brain Behav Immun 2023; 107:76-86. [PMID: 36198341 DOI: 10.1016/j.bbi.2022.09.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 08/30/2022] [Accepted: 09/30/2022] [Indexed: 02/09/2023] Open
Abstract
Current treatments for chronic pain are unsatisfactory, therefore, new therapeutics are urgently needed. Our previous study indicated that KATP channel openers have analgesic effects, but the underlying mechanism has not been elucidated. We speculated that KATP channel openers might increase suppressor of cytokine signaling (SOCS)-3 expression to induce inflammatory tolerance and attenuate chronic pain. Postoperative pain was induced by plantar incision to establish a chronic pain model. Growth arrest-specific 6 (Gas6)-/- and Axl-/- mice were used for signaling studies. The microglia cell line BV-2 was cultured for the in vitro experiments. The KATP channel opener significantly attenuated incision-induced mechanical allodynia in mice associated with the upregulated expression of SOCS3. Opening KATP channels induced the expression of SOCS3 in the Gas6/Axl signaling pathway in microglia, inhibited incision-induced mechanical allodynia by activating the Gas6/Axl-SOCS3 signaling pathway, and induced inflammatory tolerance to relieve neuroinflammation and postoperative pain. We demonstrated that opening of the KATP channel opening activated Gas6/Axl/SOCS3 signaling to induce inflammatory tolerance and relieve chronic pain. We explored a new target for anti-inflammatory and analgesic effects by regulating the innate immune system and provided a theoretical basis for clinical preemptive analgesia.
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Affiliation(s)
- Cheng Qian
- Department of Pathology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing 211166, China; Sir Run Run Hospital, Nanjing Medical University, Nanjing 211100, Jiangsu, China
| | - Yixin Fan
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China; Sir Run Run Hospital, Nanjing Medical University, Nanjing 211100, Jiangsu, China
| | - Lijuan Zong
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Chen Miao
- Department of Pathology, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Lu-Lu Ji
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Li Wan
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Rumeng Jia
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Xinmiao Qin
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Yu Wang
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China
| | - Qi Wu
- Department of Pathology, The First Affiliated Hospital with Nanjing Medical University, Nanjing 210029, Jiangsu, China
| | - Xue-You Tao
- Department of Anesthesiology, Yangzhou Maternal and Child Health Hospital Affiliated to Medical College of Yangzhou University, Yangzhou 225001, Jiangsu, China.
| | - Lanxiang Hao
- The Yancheng Clinical College of Xuzhou Medical University, The First People's Hospital of Yancheng, 224005 Jiangsu, China.
| | - Liang Hu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China.
| | - Wen-Tao Liu
- Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, Nanjing 211166, Jiangsu, China.
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Hariharan A, Robertson CD, Garcia DCG, Longden TA. Brain capillary pericytes are metabolic sentinels that control blood flow through a K ATP channel-dependent energy switch. Cell Rep 2022; 41:111872. [PMID: 36577387 PMCID: PMC10187957 DOI: 10.1016/j.celrep.2022.111872] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 10/10/2022] [Accepted: 11/30/2022] [Indexed: 12/28/2022] Open
Abstract
Despite the abundance of capillary thin-strand pericytes and their proximity to neurons and glia, little is known of the contributions of these cells to the control of brain hemodynamics. We demonstrate that the pharmacological activation of thin-strand pericyte KATP channels profoundly hyperpolarizes these cells, dilates upstream penetrating arterioles and arteriole-proximate capillaries, and increases capillary blood flow. Focal stimulation of pericytes with a KATP channel agonist is sufficient to evoke this response, mediated via KIR2.1 channel-dependent retrograde propagation of hyperpolarizing signals, whereas genetic inactivation of pericyte KATP channels eliminates these effects. Critically, we show that decreasing extracellular glucose to less than 1 mM or inhibiting glucose uptake by blocking GLUT1 transporters in vivo flips a mechanistic energy switch driving rapid KATP-mediated pericyte hyperpolarization to increase local blood flow. Together, our findings recast capillary pericytes as metabolic sentinels that respond to local energy deficits by increasing blood flow to neurons to prevent energetic shortfalls.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, USA; Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Colin D Robertson
- Department of Pharmacology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Daniela C G Garcia
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, USA; Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, School of Medicine, University of Maryland, Baltimore, MD, USA
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, USA; Laboratory of Neurovascular Interactions, Center for Biomedical Engineering and Technology, School of Medicine, University of Maryland, Baltimore, MD, USA.
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47
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Yang B, Yao JL, Huo JY, Feng YL, Coetzee WA, Xu GY, Yang HQ. Rab35 GTPase positively regulates endocytic recycling of cardiac K ATP channels. Channels (Austin) 2022; 16:137-147. [PMID: 35754325 DOI: 10.1080/19336950.2022.2090667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
ATP-sensitive K+ (KATP) channel couples membrane excitability to intracellular energy metabolism. Maintaining KATP channel surface expression is key to normal insulin secretion, blood pressure and cardioprotection. However, the molecular mechanisms regulating KATP channel internalization and endocytic recycling, which directly affect the surface expression of KATP channels, are poorly understood. Here we used the cardiac KATP channel subtype, Kir6.2/SUR2A, and characterized Rab35 GTPase as a key regulator of KATP channel endocytic recycling. Electrophysiological recordings and surface biotinylation assays showed decreased KATP channel surface density with co-expression of a dominant negative Rab35 mutant (Rab35-DN), but not other recycling-related Rab GTPases, including Rab4, Rab11a and Rab11b. Immunofluorescence images revealed strong colocalization of Rab35-DN with recycling Kir6.2. Rab35-DN minimized the recycling rate of KATP channels. Rab35 also regulated KATP channel current amplitude in isolated adult cardiomyocytes by affecting its surface expression but not channel properties, which validated its physiologic relevance and the potential of pharmacologic target for treating the diseases with KATP channel trafficking defects.
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Affiliation(s)
- Bo Yang
- Cyrus Tang Medical Institute, Soochow University, Suzhou, Jiangsu, China
| | - Jia-Lu Yao
- Department of Cardiology, the First Affiliated Hospital of Soochow University, Soochow University, Suzhou, Jiangsu, China.,Department of Cardiology, Dushu Lake Hospital Affiliated to Soochow University, Medical Center of Soochow University, Suzhou Dushu Lake Hospital, Suzhou, Jiangsu, China
| | - Jian-Yi Huo
- Cyrus Tang Medical Institute, Soochow University, Suzhou, Jiangsu, China
| | - Yu-Long Feng
- Cyrus Tang Medical Institute, Soochow University, Suzhou, Jiangsu, China
| | - William A Coetzee
- Departments of Pathology, Neuroscience & Physiology, Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, NY, USA
| | - Guang-Yin Xu
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China.,Center for Translational Medicine, The Affiliated Zhangjiagang Hospital of Soochow University, Suzhou, Jiangsu, China
| | - Hua-Qian Yang
- Cyrus Tang Medical Institute, Soochow University, Suzhou, Jiangsu, China
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Driggers CM, Shyng SL. Mechanistic insights on KATP channel regulation from cryo-EM structures. J Gen Physiol 2022; 155:213723. [PMID: 36441147 PMCID: PMC9700523 DOI: 10.1085/jgp.202113046] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/19/2022] [Accepted: 11/08/2022] [Indexed: 11/29/2022] Open
Abstract
Gated by intracellular ATP and ADP, ATP-sensitive potassium (KATP) channels couple cell energetics with membrane excitability in many cell types, enabling them to control a wide range of physiological processes based on metabolic demands. The KATP channel is a complex of four potassium channel subunits from the Kir channel family, Kir6.1 or Kir6.2, and four sulfonylurea receptor subunits, SUR1, SUR2A, or SUR2B, from the ATP-binding cassette (ABC) transporter family. Dysfunction of KATP channels underlies several human diseases. The importance of these channels in human health and disease has made them attractive drug targets. How the channel subunits interact with one another and how the ligands interact with the channel to regulate channel activity have been long-standing questions in the field. In the past 5 yr, a steady stream of high-resolution KATP channel structures has been published using single-particle cryo-electron microscopy (cryo-EM). Here, we review the advances these structures bring to our understanding of channel regulation by physiological and pharmacological ligands.
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Affiliation(s)
- Camden M. Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health and Science University, Portland, OR,Correspondence to Show-Ling Shyng:
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49
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Wei S, Behn J, Poore CP, Low SW, Nilius B, Fan H, Liao P. Binding epitope for recognition of human TRPM4 channel by monoclonal antibody M4M. Sci Rep 2022; 12:19562. [PMID: 36380063 PMCID: PMC9666640 DOI: 10.1038/s41598-022-22077-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Accepted: 10/10/2022] [Indexed: 11/16/2022] Open
Abstract
Mouse monoclonal antibody M4M was recently designed to block human TRPM4 channel. The polypeptide for generating M4M is composed of peptide A1 between the transmembrane segment 5 (S5) and the pore, and a second peptide A2 between the pore and the transmembrane segment 6 (S6). Using peptide microarray, a 4-amino acid sequence EPGF within the A2 was identified to be the binding epitope for M4M. Substitution of EPGF with other amino acids greatly reduced binding affinity. Structural analysis of human TRPM4 structure indicates that EPGF is located externally to the channel pore. A1 is close to the EPGF binding epitope in space, albeit separated by a 37-amino acid peptide. Electrophysiological study reveals that M4M could block human TRPM4, but with no effect on rodent TRPM4 which shares a different amino acid sequence ERGS for the binding motif. Our results demonstrate that M4M is a specific inhibitor for human TRPM4.
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Affiliation(s)
- Shunhui Wei
- grid.276809.20000 0004 0636 696XCalcium Signalling Laboratory, Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Julian Behn
- grid.418325.90000 0000 9351 8132Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, 138671 Singapore ,grid.4280.e0000 0001 2180 6431Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Charlene Priscilla Poore
- grid.276809.20000 0004 0636 696XCalcium Signalling Laboratory, Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - See Wee Low
- grid.276809.20000 0004 0636 696XCalcium Signalling Laboratory, Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore
| | - Bernd Nilius
- grid.5596.f0000 0001 0668 7884Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium
| | - Hao Fan
- grid.418325.90000 0000 9351 8132Bioinformatics Institute (BII), Agency for Science, Technology and Research (A*STAR), Singapore, 138671 Singapore
| | - Ping Liao
- grid.276809.20000 0004 0636 696XCalcium Signalling Laboratory, Department of Research, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore, 308433 Singapore ,grid.486188.b0000 0004 1790 4399Health and Social Sciences, Singapore Institute of Technology, Singapore, Singapore ,grid.428397.30000 0004 0385 0924Duke-NUS Medical School, Singapore, Singapore
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50
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Sung MW, Driggers CM, Mostofian B, Russo JD, Patton BL, Zuckerman DM, Shyng SL. Ligand-mediated Structural Dynamics of a Mammalian Pancreatic K ATP Channel. J Mol Biol 2022; 434:167789. [PMID: 35964676 PMCID: PMC9618280 DOI: 10.1016/j.jmb.2022.167789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/22/2022] [Accepted: 08/09/2022] [Indexed: 11/16/2022]
Abstract
Regulation of pancreatic KATP channels involves orchestrated interactions of their subunits, Kir6.2 and SUR1, and ligands. Previously we reported KATP channel cryo-EM structures in the presence and absence of pharmacological inhibitors and ATP, focusing on the mechanisms by which inhibitors act as pharmacological chaperones of KATP channels (Martin et al., 2019). Here we analyzed the same cryo-EM datasets with a focus on channel conformational dynamics to elucidate structural correlates pertinent to ligand interactions and channel gating. We found pharmacological inhibitors and ATP enrich a channel conformation in which the Kir6.2 cytoplasmic domain is closely associated with the transmembrane domain, while depleting one where the Kir6.2 cytoplasmic domain is extended away into the cytoplasm. This conformational change remodels a network of intra- and inter-subunit interactions as well as the ATP and PIP2 binding pockets. The structures resolved key contacts between the distal N-terminus of Kir6.2 and SUR1's ABC module involving residues implicated in channel function and showed a SUR1 residue, K134, participates in PIP2 binding. Molecular dynamics simulations revealed two Kir6.2 residues, K39 and R54, that mediate both ATP and PIP2 binding, suggesting a mechanism for competitive gating by ATP and PIP2.
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Affiliation(s)
- Min Woo Sung
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA. https://twitter.com/MinWooSung5
| | - Camden M Driggers
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Barmak Mostofian
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - John D Russo
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Bruce L Patton
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA
| | - Daniel M Zuckerman
- Department of Biomedical Engineering, School of Medicine, Oregon Health & Science University, Portland, OR, USA.
| | - Show-Ling Shyng
- Department of Chemical Physiology and Biochemistry, School of Medicine, Oregon Health & Science University, Portland, OR, USA.
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