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Robles-Gómez ÁA, Ordaz B, Lorea-Hernández JJ, Peña-Ortega F. Deleterious and protective effects of epothilone-D alone and in the context of amyloid β- and tau-induced alterations. Front Mol Neurosci 2023; 16:1198299. [PMID: 37900942 PMCID: PMC10603193 DOI: 10.3389/fnmol.2023.1198299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 09/20/2023] [Indexed: 10/31/2023] Open
Abstract
Amyloid-β (Aβ) and hyperphosphorylated tau (P-tau) are Alzheimer's disease (AD) biomarkers that interact in a complex manner to induce most of the cognitive and brain alterations observed in this disease. Since the neuronal cytoskeleton is a common downstream pathological target of tau and Aβ, which mostly lead to augmented microtubule instability, the administration of microtubule stabilizing agents (MSAs) can protect against their pathological actions. However, the effectiveness of MSAs is still uncertain due to their state-dependent negative effects; thus, evaluating their specific actions in different pathological or physiological conditions is required. We evaluated whether epothilone-D (Epo-D), a clinically used MSA, rescues from the functional and behavioral alterations produced by intracerebroventricular injection of Aβ, the presence of P-tau, or their combination in rTg4510 mice. We also explored the side effects of Epo-D. To do so, we evaluated hippocampal-dependent spatial memory with the Hebb-Williams maze, hippocampal CA1 integrity and the intrinsic and synaptic properties of CA1 pyramidal neurons with the patch-clamp technique. Aβ and P-tau mildly impaired memory retrieval, but produced contrasting effects on intrinsic excitability. When Aβ and P-tau were combined, the alterations in excitability and spatial reversal learning (i.e., cognitive flexibility) were exacerbated. Interestingly, Epo-D prevented most of the impairments induced Aβ and P-tau alone and combined. However, Epo-D also exhibited some side effects depending on the prevailing pathological or physiological condition, which should be considered in future preclinical and translational studies. Although we did not perform extensive histopathological evaluations or measured microtubule stability, our findings show that MSAs can rescue the consequences of AD-like conditions but otherwise be harmful if administered at a prodromal stage of the disease.
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Affiliation(s)
- Ángel Abdiel Robles-Gómez
- Instituto de Neurobiología, UNAM Campus Juriquilla, Querétaro, Mexico
- Posgrado en Ciencias Biológicas, UNAM, Ciudad Universitaria, México City, Mexico
| | - Benito Ordaz
- Instituto de Neurobiología, UNAM Campus Juriquilla, Querétaro, Mexico
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Liu T, Li T, Xu D, Wang Y, Zhou Y, Wan J, Huang CLH, Tan X. Small-conductance calcium-activated potassium channels in the heart: expression, regulation and pathological implications. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220171. [PMID: 37122223 PMCID: PMC10150224 DOI: 10.1098/rstb.2022.0171] [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: 05/02/2023] Open
Abstract
Ca2+-activated K+ channels are critical to cellular Ca2+ homeostasis and excitability; they couple intracellular Ca2+ and membrane voltage change. Of these, the small, 4-14 pS, conductance SK channels include three, KCNN1-3 encoded, SK1/KCa2.1, SK2/KCa2.2 and SK3/KCa2.3, channel subtypes with characteristic, EC50 ∼ 10 nM, 40 pM, 1 nM, apamin sensitivities. All SK channels, particularly SK2 channels, are expressed in atrial, ventricular and conducting system cardiomyocytes. Pharmacological and genetic modification results have suggested that SK channel block or knockout prolonged action potential durations (APDs) and effective refractory periods (ERPs) particularly in atrial, but also in ventricular, and sinoatrial, atrioventricular node and Purkinje myocytes, correspondingly affect arrhythmic tendency. Additionally, mitochondrial SK channels may decrease mitochondrial Ca2+ overload and reactive oxygen species generation. SK channels show low voltage but marked Ca2+ dependences (EC50 ∼ 300-500 nM) reflecting their α-subunit calmodulin (CaM) binding domains, through which they may be activated by voltage-gated or ryanodine-receptor Ca2+ channel activity. SK function also depends upon complex trafficking and expression processes and associations with other ion channels or subunits from different SK subtypes. Atrial and ventricular clinical arrhythmogenesis may follow both increased or decreased SK expression through decreased or increased APD correspondingly accelerating and stabilizing re-entrant rotors or increasing incidences of triggered activity. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- Ting Liu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Tao Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Dandi Xu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yan Wang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Yafei Zhou
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Juyi Wan
- Department of Cardiovascular Surgery, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
| | - Christopher L-H Huang
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Physiological Laboratory and Department of Biochemistry, University of Cambridge, Cambridge CB2 3EG, UK
| | - Xiaoqiu Tan
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Cardiology, the Affiliated Hospital of Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
- Department of Physiology, School of Basic Medical Sciences, Southwest Medical University, Luzhou, Sichuan 646000, People's Republic of China
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Lee J, Cho H, Kwon I. Phase separation of low-complexity domains in cellular function and disease. EXPERIMENTAL & MOLECULAR MEDICINE 2022; 54:1412-1422. [PMID: 36175485 PMCID: PMC9534829 DOI: 10.1038/s12276-022-00857-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/15/2022] [Accepted: 07/19/2022] [Indexed: 11/09/2022]
Abstract
In this review, we discuss the ways in which recent studies of low-complexity (LC) domains have challenged our understanding of the mechanisms underlying cellular organization. LC sequences, long believed to function in the absence of a molecular structure, are abundant in the proteomes of all eukaryotic organisms. Over the past decade, the phase separation of LC domains has emerged as a fundamental mechanism driving dynamic multivalent interactions of many cellular processes. We review the key evidence showing the role of phase separation of individual proteins in organizing cellular assemblies and facilitating biological function while implicating the dynamics of phase separation as a key to biological validity and functional utility. We also highlight the evidence showing that pathogenic LC proteins alter various phase separation-dependent interactions to elicit debilitating human diseases, including cancer and neurodegenerative diseases. Progress in understanding the biology of phase separation may offer useful hints toward possible therapeutic interventions to combat the toxicity of pathogenic proteins.
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Affiliation(s)
- Jiwon Lee
- Department of Anatomy and Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea
| | - Hana Cho
- Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.
| | - Ilmin Kwon
- Department of Anatomy and Cell Biology, Sungkyunkwan University School of Medicine, Suwon, 16419, Korea.
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De Zio R, Pietrafesa G, Milano S, Procino G, Bramerio M, Pepe M, Forleo C, Favale S, Svelto M, Gerbino A, Carmosino M. Role of Nuclear Lamin A/C in the Regulation of Nav1.5 Channel and Microtubules: Lesson From the Pathogenic Lamin A/C Variant Q517X. Front Cell Dev Biol 2022; 10:918760. [PMID: 35846372 PMCID: PMC9277463 DOI: 10.3389/fcell.2022.918760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 05/23/2022] [Indexed: 11/24/2022] Open
Abstract
In this work, we studied an lmna nonsense mutation encoding for the C-terminally truncated Lamin A/C (LMNA) variant Q517X, which was described in patients affected by a severe arrhythmogenic cardiomyopathy with history of sudden death. We found that LMNA Q517X stably expressed in HL-1 cardiomyocytes abnormally aggregates at the nuclear envelope and within the nucleoplasm. Whole-cell patch clamp experiments showed that LMNA Q517X-expressing cardiomyocytes generated action potentials with reduced amplitude, overshoot, upstroke velocity and diastolic potential compared with LMNA WT-expressing cardiomyocytes. Moreover, the unique features of these cardiomyocytes were 1) hyper-polymerized tubulin network, 2) upregulated acetylated α-tubulin, and 3) cell surface Nav1.5 downregulation. These findings pointed the light on the role of tubulin and Nav1.5 channel in the abnormal electrical properties of LMNA Q517X-expressing cardiomyocytes. When expressed in HEK293 with Nav1.5 and its β1 subunit, LMNA Q517X reduced the peak Na+ current (INa) up to 63% with a shift toward positive potentials in the activation curve of the channel. Of note, both AP properties in cardiomyocytes and Nav1.5 kinetics in HEK293 cells were rescued in LMNA Q517X-expressing cells upon treatment with colchicine, an FDA-approved inhibitor of tubulin assembly. In conclusion, LMNA Q517X expression is associated with hyper-polymerization and hyper-acetylation of tubulin network with concomitant downregulation of Nav1.5 cell expression and activity, thus revealing 1) new mechanisms by which LMNA may regulate channels at the cell surface in cardiomyocytes and 2) new pathomechanisms and therapeutic targets in cardiac laminopathies.
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Affiliation(s)
- Roberta De Zio
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Giusy Pietrafesa
- Department of Sciences, University of Basilicata, Potenza, Italy
| | - Serena Milano
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Giuseppe Procino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Manuela Bramerio
- ASST Grande Ospedale Metropolitano Niguarda Pathological Anatomy Center, Milano, Italy
| | - Martino Pepe
- Department of Emergency and Organ Transplantation, Cardiology Unit, University of Bari Aldo Moro, Bari, Italy
| | - Cinzia Forleo
- Department of Emergency and Organ Transplantation, Cardiology Unit, University of Bari Aldo Moro, Bari, Italy
| | - Stefano Favale
- Department of Emergency and Organ Transplantation, Cardiology Unit, University of Bari Aldo Moro, Bari, Italy
| | - Maria Svelto
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Bari, Italy
| | - Monica Carmosino
- Department of Sciences, University of Basilicata, Potenza, Italy
- *Correspondence: Monica Carmosino,
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Yang HQ, Echeverry FA, ElSheikh A, Gando I, Anez Arredondo S, Samper N, Cardozo T, Delmar M, Shyng SL, Coetzee WA. Subcellular trafficking and endocytic recycling of K ATP channels. Am J Physiol Cell Physiol 2022; 322:C1230-C1247. [PMID: 35508187 PMCID: PMC9169827 DOI: 10.1152/ajpcell.00099.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/27/2022] [Accepted: 04/30/2022] [Indexed: 11/22/2022]
Abstract
Sarcolemmal/plasmalemmal ATP-sensitive K+ (KATP) channels have key roles in many cell types and tissues. Hundreds of studies have described how the KATP channel activity and ATP sensitivity can be regulated by changes in the cellular metabolic state, by receptor signaling pathways and by pharmacological interventions. These alterations in channel activity directly translate to alterations in cell or tissue function, that can range from modulating secretory responses, such as insulin release from pancreatic β-cells or neurotransmitters from neurons, to modulating contractile behavior of smooth muscle or cardiac cells to elicit alterations in blood flow or cardiac contractility. It is increasingly becoming apparent, however, that KATP channels are regulated beyond changes in their activity. Recent studies have highlighted that KATP channel surface expression is a tightly regulated process with similar implications in health and disease. The surface expression of KATP channels is finely balanced by several trafficking steps including synthesis, assembly, anterograde trafficking, membrane anchoring, endocytosis, endocytic recycling, and degradation. This review aims to summarize the physiological and pathophysiological implications of KATP channel trafficking and mechanisms that regulate KATP channel trafficking. A better understanding of this topic has potential to identify new approaches to develop therapeutically useful drugs to treat KATP channel-related diseases.
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Affiliation(s)
- Hua-Qian Yang
- Cyrus Tang Hematology Center, Soochow University, Suzhou, People's Republic of China
| | | | - Assmaa ElSheikh
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
- Department of Medical Biochemistry, Tanta University, Tanta, Egypt
| | - Ivan Gando
- Department of Pathology, NYU School of Medicine, New York, New York
| | | | - Natalie Samper
- Department of Pathology, NYU School of Medicine, New York, New York
| | - Timothy Cardozo
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
| | - Mario Delmar
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
- Department of Medicine, NYU School of Medicine, New York, New York
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University, Portland, Oregon
| | - William A Coetzee
- Department of Pathology, NYU School of Medicine, New York, New York
- Department of Neuroscience & Physiology, NYU School of Medicine, New York, New York
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, New York
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Abstract
Heart disease remains the leading cause of morbidity and mortality worldwide. With the advancement of modern technology, the role(s) of microtubules in the pathogenesis of heart disease has become increasingly apparent, though currently there are limited treatments targeting microtubule-relevant mechanisms. Here, we review the functions of microtubules in the cardiovascular system and their specific adaptive and pathological phenotypes in cardiac disorders. We further explore the use of microtubule-targeting drugs and highlight promising druggable therapeutic targets for the future treatment of heart diseases.
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Affiliation(s)
- Emily F Warner
- Department of Medicine, University of Cambridge, Addenbrookes Hospital, United Kingdom (E.F.W., X.L.)
| | - Yang Li
- Department of Cardiovascular Surgery, Zhongnan Hospital, Wuhan University School of Medicine, People's Republic of China (Y.L.)
| | - Xuan Li
- Department of Medicine, University of Cambridge, Addenbrookes Hospital, United Kingdom (E.F.W., X.L.)
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7
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Li E, Loen V, van Ham WB, Kool W, van der Heyden MAG, Takanari H. Quantitative Analysis of the Cytoskeleton's Role in Inward Rectifier K IR 2.1 Forward and Backward Trafficking. Front Physiol 2022; 12:812572. [PMID: 35145427 PMCID: PMC8821923 DOI: 10.3389/fphys.2021.812572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 12/23/2021] [Indexed: 11/13/2022] Open
Abstract
Alteration of the inward rectifier current IK1, carried by KIR2.1 channels, affects action potential duration, impacts resting membrane stability and associates with cardiac arrhythmias. Congenital and acquired KIR2.1 malfunction frequently associates with aberrant ion channel trafficking. Cellular processes underlying trafficking are intertwined with cytoskeletal function. The extent to which the cytoskeleton is involved in KIR2.1 trafficking processes is unknown. We aimed to quantify the dependence of KIR2.1 trafficking on cytoskeleton function. GFP or photoconvertible Dendra2 tagged KIR2.1 constructs were transfected in HEK293 or HeLa cells. Photoconversion of the Dendra2 probe at the plasma membrane and subsequent live imaging of trafficking processes was performed by confocal laser-scanning microscopy. Time constant of green fluorescent recovery (τg,s) represented recruitment of new KIR2.1 at the plasma membrane. Red fluorescent decay (τr,s) represented internalization of photoconverted KIR2.1. Patch clamp electrophysiology was used to quantify IKIR2.1. Biochemical methods were used for cytoskeleton isolation and detection of KIR2.1-cytoskeleton interactions. Cytochalasin B (20 μM), Nocodazole (30 μM) and Dyngo-4a (10 nM) were used to modify the cytoskeleton. Chloroquine (10 μM, 24 h) was used to impair KIR2.1 breakdown. Cytochalasin B and Nocodazole, inhibitors of actin and tubulin filament formation respectively, strongly inhibited the recovery of green fluorescence at the plasma membrane suggestive for inhibition of KIR2.1 forward trafficking [τg,s 13 ± 2 vs. 131 ± 31* and 160 ± 40* min, for control, Cytochalasin B and Nocodazole, respectively (*p < 0.05 vs. control)]. Dyngo-4a, an inhibitor of dynamin motor proteins, strongly slowed the rate of photoconverted channel internalization, whereas Nocodazole and Cytochalasin B had less effect [τr,s 20 ± 2 vs. 87 ± 14*, 60 ± 16 and 64 ± 20 min (*p < 0.05 vs. control)]. Cytochalasin B treatment (20 μM, 24 h) inhibited IKIR2.1. Chloroquine treatment (10 μM, 24 h) induced intracellular aggregation of KIR2.1 channels and enhanced interaction with the actin/intermediate filament system (103 ± 90 fold; p < 0.05 vs. control). Functional actin and tubulin cytoskeleton systems are essential for forward trafficking of KIR2.1 channels, whereas initial backward trafficking relies on a functional dynamin system. Chronic disturbance of the actin system inhibits KIR2.1 currents. Internalized KIR2.1 channels become recruited to the cytoskeleton, presumably in lysosomes.
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Affiliation(s)
- Encan Li
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Vera Loen
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Willem B van Ham
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Willy Kool
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Marcel A G van der Heyden
- Department of Medical Physiology, Division of Heart & Lungs, University Medical Center Utrecht, Utrecht, Netherlands
| | - Hiroki Takanari
- Department of Interdisciplinary Researches for Medicine and Photonics, Institute of Post-LED Photonics, University of Tokushima, Tokushima, Japan
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Sanyal C, Pietsch N, Ramirez Rios S, Peris L, Carrier L, Moutin MJ. The detyrosination/re-tyrosination cycle of tubulin and its role and dysfunction in neurons and cardiomyocytes. Semin Cell Dev Biol 2021; 137:46-62. [PMID: 34924330 DOI: 10.1016/j.semcdb.2021.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 12/28/2022]
Abstract
Among the variety of post-translational modifications to which microtubules are subjected, the detyrosination/re-tyrosination cycle is specific to tubulin. It is conserved by evolution and characterized by the enzymatic removal and re-addition of a gene-encoded tyrosine residue at the C-terminus of α-tubulin. Detyrosinated tubulin can be further converted to Δ2-tubulin by the removal of an additional C-terminal glutamate residue. Detyrosinated and Δ2-tubulin are carried by stable microtubules whereas tyrosinated microtubules are present on dynamic polymers. The cycle regulates trafficking of many cargo transporting molecular motors and is linked to the microtubule dynamics via regulation of microtubule interactions with specific cellular effectors such as kinesin-13. Here, we give an historical overview of the general features discovered for the cycle. We highlight the recent progress toward structure and functioning of the enzymes that keep the levels of tyrosinated and detyrosinated tubulin in cells, the long-known tubulin tyrosine ligase and the recently discovered vasohibin-SVBP complexes. We further describe how the cycle controls microtubule functions in healthy neurons and cardiomyocytes and how deregulations of the cycle are involved in dysfunctions of these highly differentiated cells, leading to neurodegeneration and heart failure in humans.
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Affiliation(s)
- Chadni Sanyal
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Niels Pietsch
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Sacnicte Ramirez Rios
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Leticia Peris
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.
| | - Marie-Jo Moutin
- Univ. Grenoble Alpes, Inserm, U1216, CNRS, Grenoble Institut Neurosciences, 38000 Grenoble, France.
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Kassab S, Albalawi Z, Daghistani H, Kitmitto A. Mitochondrial Arrest on the Microtubule Highway-A Feature of Heart Failure and Diabetic Cardiomyopathy? Front Cardiovasc Med 2021; 8:689101. [PMID: 34277734 PMCID: PMC8282893 DOI: 10.3389/fcvm.2021.689101] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 06/08/2021] [Indexed: 01/16/2023] Open
Abstract
A pathophysiological consequence of both type 1 and 2 diabetes is remodelling of the myocardium leading to the loss of left ventricular pump function and ultimately heart failure (HF). Abnormal cardiac bioenergetics associated with mitochondrial dysfunction occurs in the early stages of HF. Key factors influencing mitochondrial function are the shape, size and organisation of mitochondria within cardiomyocytes, with reports identifying small, fragmented mitochondria in the myocardium of diabetic patients. Cardiac mitochondria are now known to be dynamic organelles (with various functions beyond energy production); however, the mechanisms that underpin their dynamism are complex and links to motility are yet to be fully understood, particularly within the context of HF. This review will consider how the outer mitochondrial membrane protein Miro1 (Rhot1) mediates mitochondrial movement along microtubules via crosstalk with kinesin motors and explore the evidence for molecular level changes in the setting of diabetic cardiomyopathy. As HF and diabetes are recognised inflammatory conditions, with reports of enhanced activation of the NLRP3 inflammasome, we will also consider evidence linking microtubule organisation, inflammation and the association to mitochondrial motility. Diabetes is a global pandemic but with limited treatment options for diabetic cardiomyopathy, therefore we also discuss potential therapeutic approaches to target the mitochondrial-microtubule-inflammatory axis.
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Affiliation(s)
- Sarah Kassab
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Zainab Albalawi
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Hussam Daghistani
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
| | - Ashraf Kitmitto
- Division of Cardiovascular Sciences, Faculty of Biology, Medicine and Health, School of Medical Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, United Kingdom
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10
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Li Y, Zhou X, Sun SX. Hydrogen, Bicarbonate, and Their Associated Exchangers in Cell Volume Regulation. Front Cell Dev Biol 2021; 9:683686. [PMID: 34249935 PMCID: PMC8264760 DOI: 10.3389/fcell.2021.683686] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/31/2021] [Indexed: 11/25/2022] Open
Abstract
Cells lacking a stiff cell wall, e.g., mammalian cells, must actively regulate their volume to maintain proper cell function. On the time scale that protein production is negligible, water flow in and out of the cell determines the cell volume variation. Water flux follows hydraulic and osmotic gradients; the latter is generated by various ion channels, transporters, and pumps in the cell membrane. Compared to the widely studied roles of sodium, potassium, and chloride in cell volume regulation, the effects of proton and bicarbonate are less understood. In this work, we use mathematical models to analyze how proton and bicarbonate, combined with sodium, potassium, chloride, and buffer species, regulate cell volume upon inhibition of ion channels, transporters, and pumps. The model includes several common, widely expressed ion transporters and focuses on obtaining generic outcomes. Results show that the intracellular osmolarity remains almost constant before and after cell volume change. The steady-state cell volume does not depend on water permeability. In addition, to ensure the stability of cell volume and ion concentrations, cells need to develop redundant mechanisms to maintain homeostasis, i.e., multiple ion channels or transporters are involved in the flux of the same ion species. These results provide insights for molecular mechanisms of cell volume regulation with additional implications for water-driven cell migration.
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Affiliation(s)
- Yizeng Li
- Department of Mechanical Engineering, Kennesaw State University, Marietta, GA, United States
| | - Xiaohan Zhou
- Department of Physics, University of Toronto, Toronto, ON, Canada
| | - Sean X. Sun
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, United States
- Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD, United States
- Center for Cell Dynamics, Johns Hopkins School of Medicine, Baltimore, MD, United States
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11
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Chatterjee D, Pieroni M, Fatah M, Charpentier F, Cunningham KS, Spears DA, Chatterjee D, Suna G, Bos JM, Ackerman MJ, Schulze-Bahr E, Dittmann S, Notarstefano PG, Bolognese L, Duru F, Saguner AM, Hamilton RM. An autoantibody profile detects Brugada syndrome and identifies abnormally expressed myocardial proteins. Eur Heart J 2021; 41:2878-2890. [PMID: 32533187 DOI: 10.1093/eurheartj/ehaa383] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 03/23/2020] [Accepted: 04/24/2020] [Indexed: 12/17/2022] Open
Abstract
AIMS Brugada syndrome (BrS) is characterized by a unique electrocardiogram (ECG) pattern and life-threatening arrhythmias. However, the Type 1 Brugada ECG pattern is often transient, and a genetic cause is only identified in <25% of patients. We sought to identify an additional biomarker for this rare condition. As myocardial inflammation may be present in BrS, we evaluated whether myocardial autoantibodies can be detected in these patients. METHODS AND RESULTS For antibody (Ab) discovery, normal human ventricular myocardial proteins were solubilized and separated by isoelectric focusing (IEF) and molecular weight on two-dimensional (2D) gels and used to discover Abs by plating with sera from patients with BrS and control subjects. Target proteins were identified by mass spectrometry (MS). Brugada syndrome subjects were defined based on a consensus clinical scoring system. We assessed discovery and validation cohorts by 2D gels, western blots, and ELISA. We performed immunohistochemistry on myocardium from BrS subjects (vs. control). All (3/3) 2D gels exposed to sera from BrS patients demonstrated specific Abs to four proteins, confirmed by MS to be α-cardiac actin, α-skeletal actin, keratin, and connexin-43, vs. 0/8 control subjects. All (18/18) BrS subjects from our validation cohorts demonstrated the same Abs, confirmed by western blots, vs. 0/24 additional controls. ELISA optical densities for all Abs were elevated in all BrS subjects compared to controls. In myocardium obtained from BrS subjects, each protein, as well as SCN5A, demonstrated abnormal protein expression in aggregates. CONCLUSION A biomarker profile of autoantibodies against four cardiac proteins, namely α-cardiac actin, α-skeletal actin, keratin, and connexin-43, can be identified from sera of BrS patients and is highly sensitive and specific, irrespective of genetic cause for BrS. The four involved proteins, along with the SCN5A-encoded Nav1.5 alpha subunit are expressed abnormally in the myocardium of patients with BrS.
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Affiliation(s)
- Diptendu Chatterjee
- Department of Pediatrics, The Labatt Family Heart Centre and Translational Medicine, The Hospital for Sick Children & Research Institute and the University of Toronto, Room 1725D, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Maurizio Pieroni
- Cardiovascular Department, San Donato Hospital, Via Curtatone 54 - 52100 Arezzo, Italy
| | - Meena Fatah
- Department of Pediatrics, The Labatt Family Heart Centre and Translational Medicine, The Hospital for Sick Children & Research Institute and the University of Toronto, Room 1725D, 555 University Avenue, Toronto, ON M5G 1X8, Canada
| | - Flavien Charpentier
- L'Institut du Thorax, INSERM, CNRS, UNIV Nantes, 8 quai Moncousu, 44007 Nantes, France
| | - Kristopher S Cunningham
- Department of Laboratory Medicine and Pathobiology, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
| | - Danna A Spears
- Department of Medicine, University Health Network-Toronto General Hospital, 200 Elizabeth Street 4NU-492, Toronto, Ontario M5G 2C4, Canada
| | - Dipashree Chatterjee
- Department of Psychology, University of Toronto, 27 King's College Circle, Toronto, Ontario M5S 1A1, Canada
| | - Gonca Suna
- Department of Cardiology, University Heart Center Zurich, Rämistrasse 100, 8091 Zürich, Switzerland
| | - J Martjin Bos
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, MN, USA.,Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA
| | - Michael J Ackerman
- Department of Cardiovascular Medicine, Division of Heart Rhythm Services, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, MN, USA.,Department of Pediatric and Adolescent Medicine, Division of Pediatric Cardiology, Mayo Clinic, Rochester, MN, USA.,Department of Molecular Pharmacology and Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN, USA
| | - Eric Schulze-Bahr
- Institute for Genetics of Heart Diseases, Department für Kardiologie und Angiologie, Zentrum für Innere Medizin, Universitätsklinikum Münster Albert-Schweitzer-Campus 1, Gebäude D3 48149 Münster, Germany
| | - Sven Dittmann
- Institute for Genetics of Heart Diseases, Department für Kardiologie und Angiologie, Zentrum für Innere Medizin, Universitätsklinikum Münster Albert-Schweitzer-Campus 1, Gebäude D3 48149 Münster, Germany
| | | | - Leonardo Bolognese
- Cardiovascular Department, San Donato Hospital, Via Curtatone 54 - 52100 Arezzo, Italy
| | - Firat Duru
- Department of Cardiology, University Heart Center Zurich, Rämistrasse 100, 8091 Zürich, Switzerland
| | - Ardan M Saguner
- Department of Cardiology, University Heart Center Zurich, Rämistrasse 100, 8091 Zürich, Switzerland
| | - Robert M Hamilton
- Department of Pediatrics, The Labatt Family Heart Centre and Translational Medicine, The Hospital for Sick Children & Research Institute and the University of Toronto, Room 1725D, 555 University Avenue, Toronto, ON M5G 1X8, Canada
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12
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van der Horst J, Rognant S, Abbott GW, Ozhathil LC, Hägglund P, Barrese V, Chuang CY, Jespersen T, Davies MJ, Greenwood IA, Gourdon P, Aalkjær C, Jepps TA. Dynein regulates Kv7.4 channel trafficking from the cell membrane. J Gen Physiol 2021; 153:211752. [PMID: 33533890 PMCID: PMC7863719 DOI: 10.1085/jgp.202012760] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 12/21/2020] [Accepted: 01/08/2021] [Indexed: 12/15/2022] Open
Abstract
The dynein motor protein transports proteins away from the cell membrane along the microtubule network. Recently, we found the microtubule network was important for regulating the membrane abundance of voltage-gated Kv7.4 potassium channels in vascular smooth muscle. Here, we aimed to investigate the influence of dynein on the microtubule-dependent internalization of the Kv7.4 channel. Patch-clamp recordings from HEK293B cells showed Kv7.4 currents were increased after inhibiting dynein function with ciliobrevin D or by coexpressing p50/dynamitin, which specifically interferes with dynein motor function. Mutation of a dynein-binding site in the Kv7.4 C terminus increased the Kv7.4 current and prevented p50 interference. Structured illumination microscopy, proximity ligation assays, and coimmunoprecipitation showed colocalization of Kv7.4 and dynein in mesenteric artery myocytes. Ciliobrevin D enhanced mesenteric artery relaxation to activators of Kv7.2–Kv7.5 channels and increased membrane abundance of Kv7.4 protein in isolated smooth muscle cells and HEK293B cells. Ciliobrevin D failed to enhance the negligible S-1–mediated relaxations after morpholino-mediated knockdown of Kv7.4. Mass spectrometry revealed an interaction of dynein with caveolin-1, confirmed using proximity ligation and coimmunoprecipitation assays, which also provided evidence for interaction of caveolin-1 with Kv7.4, confirming that Kv7.4 channels are localized to caveolae in mesenteric artery myocytes. Lastly, cholesterol depletion reduced the interaction of Kv7.4 with caveolin-1 and dynein while increasing the overall membrane expression of Kv7.4, although it attenuated the Kv7.4 current in oocytes and interfered with the action of ciliobrevin D and channel activators in arterial segments. Overall, this study shows that dynein can traffic Kv7.4 channels in vascular smooth muscle in a mechanism dependent on cholesterol-rich caveolae.
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Affiliation(s)
| | - Salomé Rognant
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Geoffrey W Abbott
- Bioelectricity Laboratory, Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA
| | | | - Per Hägglund
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Vincenzo Barrese
- St. George's, University of London, London, UK.,Department of Neuroscience, Reproductive Science and Dentistry, University of Naples "Federico II," Naples, Italy
| | - Christine Y Chuang
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Jespersen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Pontus Gourdon
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Medical Sciences, Lund University, Lund, Sweden
| | - Christian Aalkjær
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - Thomas A Jepps
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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13
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van der Horst J, Greenwood IA, Jepps TA. Cyclic AMP-Dependent Regulation of Kv7 Voltage-Gated Potassium Channels. Front Physiol 2020; 11:727. [PMID: 32695022 PMCID: PMC7338754 DOI: 10.3389/fphys.2020.00727] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 06/04/2020] [Indexed: 01/08/2023] Open
Abstract
Voltage-gated Kv7 potassium channels, encoded by KCNQ genes, have major physiological impacts cardiac myocytes, neurons, epithelial cells, and smooth muscle cells. Cyclic adenosine monophosphate (cAMP), a well-known intracellular secondary messenger, can activate numerous downstream effector proteins, generating downstream signaling pathways that regulate many functions in cells. A role for cAMP in ion channel regulation has been established, and recent findings show that cAMP signaling plays a role in Kv7 channel regulation. Although cAMP signaling is recognized to regulate Kv7 channels, the precise molecular mechanism behind the cAMP-dependent regulation of Kv7 channels is complex. This review will summarize recent research findings that support the mechanisms of cAMP-dependent regulation of Kv7 channels.
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Affiliation(s)
- Jennifer van der Horst
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Iain A Greenwood
- Molecular and Clinical Sciences Institute, St. George's University of London, London, United Kingdom
| | - Thomas A Jepps
- Vascular Biology Group, Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
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14
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Guerra MJ, González‐Jamett AM, Báez‐Matus X, Navarro‐Quezada N, Martínez AD, Neely A, Cárdenas AM. The Ca2+channel subunit CaVβ2a‐subunit down‐regulates voltage‐activated ion current densities by disrupting actin‐dependent traffic in chromaffin cells. J Neurochem 2019; 151:703-715. [DOI: 10.1111/jnc.14851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 05/01/2019] [Accepted: 08/05/2019] [Indexed: 12/11/2022]
Affiliation(s)
- María J. Guerra
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia Universidad de Valparaíso Valparaíso Chile
| | - Arlek M. González‐Jamett
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia Universidad de Valparaíso Valparaíso Chile
| | - Ximena Báez‐Matus
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia Universidad de Valparaíso Valparaíso Chile
| | - Nieves Navarro‐Quezada
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia Universidad de Valparaíso Valparaíso Chile
| | - Agustín D. Martínez
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia Universidad de Valparaíso Valparaíso Chile
| | - Alan Neely
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia Universidad de Valparaíso Valparaíso Chile
| | - Ana M. Cárdenas
- Facultad de Ciencias, Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia Universidad de Valparaíso Valparaíso Chile
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15
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Caporizzo MA, Chen CY, Prosser BL. Cardiac microtubules in health and heart disease. Exp Biol Med (Maywood) 2019; 244:1255-1272. [PMID: 31398994 DOI: 10.1177/1535370219868960] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes are large (∼40,000 µm3), rod-shaped muscle cells that provide the working force behind each heartbeat. These highly structured cells are packed with dense cytoskeletal networks that can be divided into two groups—the contractile (i.e. sarcomeric) cytoskeleton that consists of filamentous actin-myosin arrays organized into myofibrils, and the non-sarcomeric cytoskeleton, which is composed of β- and γ-actin, microtubules, and intermediate filaments. Together, microtubules and intermediate filaments form a cross-linked scaffold, and these networks are responsible for the delivery of intracellular cargo, the transmission of mechanical signals, the shaping of membrane systems, and the organization of myofibrils and organelles. Microtubules are extensively altered as part of both adaptive and pathological cardiac remodeling, which has diverse ramifications for the structure and function of the cardiomyocyte. In heart failure, the proliferation and post-translational modification of the microtubule network is linked to a number of maladaptive processes, including the mechanical impediment of cardiomyocyte contraction and relaxation. This raises the possibility that reversing microtubule alterations could improve cardiac performance, yet therapeutic efforts will strongly benefit from a deeper understanding of basic microtubule biology in the heart. The aim of this review is to summarize the known physiological roles of the cardiomyocyte microtubule network, the consequences of its pathological remodeling, and to highlight the open and intriguing questions regarding cardiac microtubules. Impact statement Advancements in cell biological and biophysical approaches and super-resolution imaging have greatly broadened our view of tubulin biology over the last decade. In the heart, microtubules and microtubule-based transport help to organize and maintain key structures within the cardiomyocyte, including the sarcomere, intercalated disc, protein clearance machinery and transverse-tubule and sarcoplasmic reticulum membranes. It has become increasingly clear that post translational regulation of microtubules is a key determinant of their sub-cellular functionality. Alterations in microtubule network density, stability, and post-translational modifications are hallmarks of pathological cardiac remodeling, and modified microtubules can directly impede cardiomyocyte contractile function in various forms of heart disease. This review summarizes the functional roles and multi-leveled regulation of the cardiac microtubule cytoskeleton and highlights how refined experimental techniques are shedding mechanistic clarity on the regionally specified roles of microtubules in cardiac physiology and pathophysiology.
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Affiliation(s)
- Matthew A Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Christina Yingxian Chen
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.,Penn Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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16
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Callaghan NI, Hadipour-Lakmehsari S, Lee SH, Gramolini AO, Simmons CA. Modeling cardiac complexity: Advancements in myocardial models and analytical techniques for physiological investigation and therapeutic development in vitro. APL Bioeng 2019; 3:011501. [PMID: 31069331 PMCID: PMC6481739 DOI: 10.1063/1.5055873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 12/31/2018] [Indexed: 02/06/2023] Open
Abstract
Cardiomyopathies, heart failure, and arrhythmias or conduction blockages impact millions of patients worldwide and are associated with marked increases in sudden cardiac death, decline in the quality of life, and the induction of secondary pathologies. These pathologies stem from dysfunction in the contractile or conductive properties of the cardiomyocyte, which as a result is a focus of fundamental investigation, drug discovery and therapeutic development, and tissue engineering. All of these foci require in vitro myocardial models and experimental techniques to probe the physiological functions of the cardiomyocyte. In this review, we provide a detailed exploration of different cell models, disease modeling strategies, and tissue constructs used from basic to translational research. Furthermore, we highlight recent advancements in imaging, electrophysiology, metabolic measurements, and mechanical and contractile characterization modalities that are advancing our understanding of cardiomyocyte physiology. With this review, we aim to both provide a biological framework for engineers contributing to the field and demonstrate the technical basis and limitations underlying physiological measurement modalities for biologists attempting to take advantage of these state-of-the-art techniques.
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Affiliation(s)
| | | | | | | | - Craig A. Simmons
- Author to whom correspondence should be addressed: . Present address: Ted Rogers Centre for Heart
Research, 661 University Avenue, 14th Floor Toronto, Ontario M5G 1M1, Canada. Tel.:
416-946-0548. Fax: 416-978-7753
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17
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Kovalchuk V, Samluk Ł, Juraszek B, Jurkiewicz-Trząska D, Sucic S, Freissmuth M, Nałęcz KA. Trafficking of the amino acid transporter B 0,+ (SLC6A14) to the plasma membrane involves an exclusive interaction with SEC24C for its exit from the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2018; 1866:252-263. [PMID: 30445147 PMCID: PMC6314439 DOI: 10.1016/j.bbamcr.2018.11.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 11/02/2018] [Accepted: 11/12/2018] [Indexed: 12/16/2022]
Abstract
A plasma membrane amino acid transporter B0,+ (ATB0,+), encoded by the SLC6A14 gene, is specific for neutral and basic amino acids. It is up-regulated in several types of malignant cancers. Neurotransmitter transporters of the SLC6 family interact with specific SEC24 proteins of the COPII complex along their pathway from the endoplasmic reticulum (ER) to Golgi. This study focused on the possible role of SEC24 proteins in ATB0,+ trafficking. Rat ATB0,+ was expressed in HEK293 cells, its localization and trafficking were examined by Western blot, deglycosylation, immunofluorescence (co-localization with ER and trans-Golgi markers) and biotinylation. The expression of ATB0,+ at the plasma membrane was decreased by dominant negative mutants of SAR1, a GTPase, whose activity triggers the formation of the COPII complex. ATB0,+ co-precipitated with SEC24C (but not with the remaining isoforms A, B and D). This interaction was confirmed by immunocytochemistry and the proximity ligation assay. Co-localization of SEC24C with endogenous ATB0,+ was also observed in MCF-7 breast cancer cells. Contrary to the endogenous transporter, part of the overexpressed ATB0,+ is directed to proteolysis, a process significantly reversed by a proteasome inhibitor bortezomib. Co-transfection with a SEC24C dominant negative mutant attenuated ATB0,+ expression at the plasma membrane, due to proteolytic degradation. These results support a hypothesis that lysine at position +2 downstream of the ER export "RI" motif on the cargo protein is crucial for SEC24C binding and for further trafficking to the Golgi. Moreover, there is an equilibrium between ER export and degradation mechanisms in case of overexpressed transporter.
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Affiliation(s)
- Vasylyna Kovalchuk
- Laboratory of Transport through Biomembranes, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Łukasz Samluk
- Laboratory of Transport through Biomembranes, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Barbara Juraszek
- Laboratory of Transport through Biomembranes, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Dominika Jurkiewicz-Trząska
- Laboratory of Transport through Biomembranes, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Katarzyna A Nałęcz
- Laboratory of Transport through Biomembranes, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur Street, 02-093 Warsaw, Poland.
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18
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Ion channels as part of macromolecular multiprotein complexes : Clinical significance. Herzschrittmacherther Elektrophysiol 2017; 29:30-35. [PMID: 29214349 PMCID: PMC5846830 DOI: 10.1007/s00399-017-0542-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 10/11/2017] [Indexed: 11/17/2022]
Abstract
Ion channels and Ca2+-handling proteins involved in the regulation of cardiac electrophysiology and contractility are organized in macromolecular multiprotein complexes. Recent molecular and cellular studies have significantly enhanced our understanding of the composition of these macromolecular complexes and have helped to elucidate their role in the dynamic regulation of ion channel function. Moreover, it has become clear that alterations in the composition of ion channel macromolecular complexes, for example, due to genetic mutations or acquired alterations in the expression of individual components, may lead to ion channel dysfunction and arrhythmogenesis. Here, we review novel insights into the composition of the major ion channel macromolecular complexes and discuss the potential clinical significance of alterations in these dynamic multiprotein structures.
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19
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Abstract
Voltage-gated sodium channels (VGSC) are critical determinants of cellular electrical activity through the control of initiation and propagation of action potential. To ensure this role, these proteins are not consistently delivered to the plasma membrane but undergo drastic quality controls throughout various adaptive processes such as biosynthesis, anterograde and retrograde trafficking, and membrane targeting. In pathological conditions, this quality control could lead to the retention of functional VGSC and is therefore the target of different pharmacological approaches. The present chapter gives an overview of the current understanding of the facets of VGSC life cycle in the context of both cardiac and neuronal cell types.
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Affiliation(s)
- A Mercier
- Laboratoire de Signalisation et Transports Ioniques Membranaires, Pôle Biologie Santé, Université de Poitiers, CNRS, 1 rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - P Bois
- Laboratoire de Signalisation et Transports Ioniques Membranaires, Pôle Biologie Santé, Université de Poitiers, CNRS, 1 rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France
| | - A Chatelier
- Laboratoire de Signalisation et Transports Ioniques Membranaires, Pôle Biologie Santé, Université de Poitiers, CNRS, 1 rue Georges Bonnet, TSA 51106, 86073, Poitiers Cedex 9, France.
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20
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Neethling A, Mouton J, Loos B, Corfield V, de Villiers C, Kinnear C. Filamin C: a novel component of the KCNE2 interactome during hypoxia. Cardiovasc J Afr 2016; 27:4-11. [PMID: 26956495 PMCID: PMC4816932 DOI: 10.5830/cvja-2015-049] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 05/17/2015] [Indexed: 12/16/2022] Open
Abstract
Aim KCNE2 encodes for the potassium voltage-gated channel, KCNE2. Mutations in KCNE2 have been associated with long-QT syndrome (LQTS). While KCNE2 has been extensively studied, the functions of its C-terminal domain remain inadequately described. Here, we aimed to elucidate the functions of this domain by identifying its protein interactors using yeast two-hybrid analysis. Methods The C-terminal domain of KCNE2 was used as bait to screen a human cardiac cDNA library for putative interacting proteins. Co-localisation and co-immunoprecipitation analyses were used for verification. Results Filamin C (FLNC) was identified as a putative interactor with KCNE2. FLNC and KCNE2 co-localised within the cell, however, a physical interaction was only observed under hypoxic conditions. Conclusion The identification of FLNC as a novel KCNE2 ligand not only enhances current understanding of ion channel function and regulation, but also provides valuable information about possible pathways likely to be involved in LQTS pathogenesis.
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Affiliation(s)
- Annika Neethling
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Jomien Mouton
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Ben Loos
- Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch, South Africa
| | - Valerie Corfield
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Carin de Villiers
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - Craig Kinnear
- DST/NRF Centre of Excellence in Biomedical Tuberculosis Research, SA MRC Centre for Tuberculosis Research, Division of Molecular Biology and Human Genetics, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
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21
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Zhang Z, Ledford HA, Park S, Wang W, Rafizadeh S, Kim HJ, Xu W, Lu L, Lau VC, Knowlton AA, Zhang XD, Yamoah EN, Chiamvimonvat N. Distinct subcellular mechanisms for the enhancement of the surface membrane expression of SK2 channel by its interacting proteins, α-actinin2 and filamin A. J Physiol 2016; 595:2271-2284. [PMID: 27779751 PMCID: PMC5374114 DOI: 10.1113/jp272942] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 10/19/2016] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Ion channels are transmembrane proteins that are synthesized within the cells but need to be trafficked to the cell membrane for the channels to function. Small-conductance, Ca2+ -activated K+ channels (SK, KCa 2) are unique subclasses of K+ channels that are regulated by Ca2+ inside the cells; they are expressed in human atrial myocytes and responsible for shaping atrial action potentials. We have previously shown that interacting proteins of SK2 channels are important for channel trafficking to the membrane. Using total internal reflection fluorescence (TIRF) and confocal microscopy, we studied the mechanisms by which the surface membrane localization of SK2 (KCa 2.2) channels is regulated by their interacting proteins. Understanding the mechanisms of SK channel trafficking may provide new insights into the regulation controlling the repolarization of atrial myocytes. ABSTRACT The normal function of ion channels depends critically on the precise subcellular localization and the number of channel proteins on the cell surface membrane. Small-conductance, Ca2+ -activated K+ channels (SK, KCa 2) are expressed in human atrial myocytes and are responsible for shaping atrial action potentials. Understanding the mechanisms of SK channel trafficking may provide new insights into the regulation controlling the repolarization of atrial myocytes. We have previously demonstrated that the C- and N-termini of SK2 channels interact with the actin-binding proteins α-actinin2 and filamin A, respectively. However, the roles of the interacting proteins on SK2 channel trafficking remain incompletely understood. Using total internal reflection fluorescence (TIRF) microscopy, we studied the mechanisms of surface membrane localization of SK2 (KCa 2.2) channels. When SK2 channels were co-expressed with filamin A or α-actinin2, the membrane fluorescence intensity of SK2 channels increased significantly. We next tested the effects of primaquine and dynasore on SK2 channels expression. Treatment with primaquine significantly reduced the membrane expression of SK2 channels. In contrast, treatment with dynasore failed to alter the surface membrane expression of SK2 channels. Further investigations using constitutively active or dominant-negative forms of Rab GTPases provided additional insights into the distinct roles of the two cytoskeletal proteins on the recycling processes of SK2 channels from endosomes. α-Actinin2 facilitated recycling of SK2 channels from both early and recycling endosomes while filamin A probably aids the recycling of SK2 channels from recycling endosomes.
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Affiliation(s)
- Zheng Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Hannah A Ledford
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Seojin Park
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Wenying Wang
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV, 89557, USA
| | - Sassan Rafizadeh
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Hyo Jeong Kim
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Wilson Xu
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Ling Lu
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA.,Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology, College of Life Sciences, Nanjing Normal University, Nanjing, 210046, China
| | - Victor C Lau
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Anne A Knowlton
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA, 95655, USA
| | - Xiao-Dong Zhang
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA
| | - Ebenezer N Yamoah
- Department of Physiology and Cell Biology, University of Nevada, Reno, NV, 89557, USA
| | - Nipavan Chiamvimonvat
- Division of Cardiovascular Medicine, Department of Internal Medicine, University of California, Davis, CA, 95616, USA.,Department of Veterans Affairs, Northern California Health Care System, Mather, CA, 95655, USA
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Liu G, Honisch S, Liu G, Schmidt S, Alkahtani S, AlKahtane AA, Stournaras C, Lang F. Up-regulation of Orai1 expression and store operated Ca(2+) entry following activation of membrane androgen receptors in MCF-7 breast tumor cells. BMC Cancer 2015; 15:995. [PMID: 26690689 PMCID: PMC4687293 DOI: 10.1186/s12885-015-2014-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 12/15/2015] [Indexed: 12/20/2022] Open
Abstract
Background Membrane androgen receptors (mAR) are functionally expressed in a variety of tumor-cells including the breast tumor-cell line MCF-7. They are specifically activated by testosterone albumin conjugates (TAC). The mAR sensitive signaling includes activation of Ras-related C3 botulinum toxin substrate 1 (Rac1) and reorganization of the actin filament network. Signaling of tumor-cells may further involve up-regulation of pore forming Ca2+ channel protein Orai1, which accomplishes store operated Ca2+ entry (SOCE). This study explored the regulation of Orai1 abundance and SOCE by mAR. Methods Actin filaments were visualized utilizing confocal microscopy, Rac1 activity using GST-GBD assay, Orai1 transcript levels by RT-PCR and total protein abundance by western blotting, Orai1 abundance at the cell surface by confocal microscopy and FACS-analysis, cytosolic Ca2+ activity ([Ca2+]i) utilizing Fura-2-fluorescence, and SOCE from increase of [Ca2+]i following readdition of Ca2+ after store depletion with thapsigargin (1 μM). Results TAC treatment of MCF-7 cells was followed by Rac1 activation, actin polymerization, transient increase of Orai1transcript levels and protein abundance, and transient increase of SOCE. The transient increase of Orai1 protein abundance was abrogated by Rac1 inhibitor NSC23766 (50 μM) and by prevention of actin reorganization with cytochalasin B (1 μM). Conclusions mAR sensitive Rac1 activation and actin reorganization contribute to the regulation of Orai1 protein abundance and SOCE.
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Affiliation(s)
- Guilai Liu
- Department of Physiology, University of Tuebingen, Tuebingen, Germany.
| | - Sabina Honisch
- Department of Physiology, University of Tuebingen, Tuebingen, Germany.
| | - Guoxing Liu
- Department of Physiology, University of Tuebingen, Tuebingen, Germany.
| | - Sebastian Schmidt
- Department of Physiology, University of Tuebingen, Tuebingen, Germany.
| | - Saad Alkahtani
- Department of Biochemistry, University of Crete Medical School, Heraklion, Crete, Greece. .,Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia.
| | - Abdullah A AlKahtane
- Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia.
| | - Christos Stournaras
- Department of Physiology, University of Tuebingen, Tuebingen, Germany. .,Department of Biochemistry, University of Crete Medical School, Heraklion, Crete, Greece.
| | - Florian Lang
- Department of Physiology, University of Tuebingen, Tuebingen, Germany. .,Physiologisches Institut, der Universität Tübingen, Gmelinstr. 5, D-72076, Tübingen, Germany.
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Saffitz JE. Protein trafficking in cardiovascular disease: How the science has evolved and where it must go. Trends Cardiovasc Med 2015; 25:390-1. [DOI: 10.1016/j.tcm.2015.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 01/06/2015] [Indexed: 02/06/2023]
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Vatta M, Spoonamore KG. Use of genetic testing to identify sudden cardiac death syndromes. Trends Cardiovasc Med 2015; 25:738-48. [PMID: 25864170 DOI: 10.1016/j.tcm.2015.03.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 03/06/2015] [Accepted: 03/07/2015] [Indexed: 01/25/2023]
Abstract
Sudden cardiac death (SCD) is a leading cause of mortality worldwide. Although coronary artery disease remains the most common substrate for SCD, primary cardiac genetic diseases, presenting with or without structural heart abnormalities, play a significant role. In the last 30 years, the study of large family pedigrees allowed the discovery of causative genes unveiling the genetic basis of diseases such as primary cardiomyopathies and arrhythmia syndromes, which are known to increase the risk of SCD. However, recent technological advancement with the ability to perform massive parallel sequencing and analyze the entire genome has uncovered a higher level of complexity in the genetic predisposition for cardiac diseases, which are usually characterized by Mendelian inheritance patterns. Clinical genetic testing, historically shaped around a monogenic Mendelian disorder paradigm, is now facing the challenge to adopt and adapt to a more complex model in which a significant portion of subjects may present with multi-allelic inheritance involving additional genes that could modulate the severity and type of disease-related phenotypes. Here, we will try to provide a viewpoint that will hopefully foster further debate in the field.
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Affiliation(s)
- Matteo Vatta
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN; Department of Medicine, Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, IN.
| | - Katherine G Spoonamore
- Department of Medicine, Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, IN
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Hervé JC. Reciprocal influences between cell cytoskeleton and membrane channels, receptors and transporters. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:511-3. [PMID: 24373689 DOI: 10.1016/j.bbamem.2013.10.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Jean-Claude Hervé
- Institut de Physiologie et Biologie Cellulaires, FRE 3511, CNRS, Université de Poitiers, PBS, Bât: B36 - 1 rue Georges Bonnet, 86022 POITIERS Cédex, France
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