المؤلفون: Arie O. Verkerk, Suzan J. G. Knottnerus, Vincent Portero, Jeannette C. Bleeker, Sacha Ferdinandusse, Kaomei Guan, Lodewijk IJlst, Gepke Visser, Ronald J. A. Wanders, Frits A. Wijburg, Connie R. Bezzina, Isabella Mengarelli, Riekelt H. Houtkooper

المصدر: Frontiers in Pharmacology, Vol 11 (2021)

مصطلحات موضوعية: very long-chain acyl-CoA dehydrogenase, arrhythmia < cardiovascular, acylcarnitines, action potential, human induced pluripotent stem cell derived cardiomyocytes, patients, Therapeutics. Pharmacology, RM1-950

الوصف: Patients with a deficiency in very long-chain acyl-CoA dehydrogenase (VLCAD), an enzyme that is involved in the mitochondrial beta-oxidation of long-chain fatty acids, are at risk for developing cardiac arrhythmias. In human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs), VLCAD deficiency (VLCADD) results in a series of abnormalities, including: 1) accumulation of long-chain acylcarnitines, 2) action potential shortening, 3) higher systolic and diastolic intracellular Ca2+ concentrations, and 4) development of delayed afterdepolarizations. In the fatty acid oxidation process, carnitine is required for bidirectional transport of acyl groups across the mitochondrial membrane. Supplementation has been suggested as potential therapeutic approach in VLCADD, but its benefits are debated. Here, we studied the effects of carnitine supplementation on the long-chain acylcarnitine levels and performed electrophysiological analyses in VLCADD patient-derived hiPSC-CMs with a ACADVL gene mutation (p.Val283Ala/p.Glu381del). Under standard culture conditions, VLCADD hiPSC-CMs showed high concentrations of long-chain acylcarnitines, short action potentials, and high delayed afterdepolarizations occurrence. Incubation of the hiPSC-CMs with 400 µM L-carnitine for 48 h led to increased long-chain acylcarnitine levels both in medium and cells. In addition, carnitine supplementation neither restored abnormal action potential parameters nor the increased occurrence of delayed afterdepolarizations in VLCADD hiPSC-CMs. We conclude that long-chain acylcarnitine accumulation and electrophysiological abnormalities in VLCADD hiPSC-CMs are not normalized by carnitine supplementation, indicating that this treatment is unlikely to be beneficial against cardiac arrhythmias in VLCADD patients.

وصف الملف: electronic resource

العلاقة: https://www.frontiersin.org/articles/10.3389/fphar.2020.616834/fullTest; https://doaj.org/toc/1663-9812Test

الوصول الحر: https://doaj.org/article/9bf15979cc1e485ca8dbed0f9ba01156Test

المؤلفون: Simona Casini, Maxime Albesa, Zizun Wang, Vincent Portero, Daniela Ross-Kaschitza, Jean-Sébastien Rougier, Gerard A. Marchal, Wendy K. Chung, Connie R. Bezzina, Hugues Abriel, Carol Ann Remme

المصدر: International Journal of Molecular Sciences, Vol 20, Iss 20, p 5033 (2019)

مصطلحات موضوعية: scn5a, ubiquitylation, long qt syndrome, sodium current, nedd4-2, action potential, patch-clamp, mouse model, Biology (General), QH301-705.5, Chemistry, QD1-999

الوصف: Dysfunction of the cardiac sodium channel Nav1.5 (encoded by the SCN5A gene) is associated with arrhythmias and sudden cardiac death. SCN5A mutations associated with long QT syndrome type 3 (LQT3) lead to enhanced late sodium current and consequent action potential (AP) prolongation. Internalization and degradation of Nav1.5 is regulated by ubiquitylation, a post-translational mechanism that involves binding of the ubiquitin ligase Nedd4-2 to a proline-proline-serine-tyrosine sequence of Nav1.5, designated the PY-motif. We investigated the biophysical properties of the LQT3-associated SCN5A-p.Y1977N mutation located in the Nav1.5 PY-motif, both in HEK293 cells as well as in newly generated mice harboring the mouse homolog mutation Scn5a-p.Y1981N. We found that in HEK293 cells, the SCN5A-p.Y1977N mutation abolished the interaction between Nav1.5 and Nedd4-2, suppressed PY-motif-dependent ubiquitylation of Nav1.5, and consequently abrogated Nedd4-2 induced sodium current (INa) decrease. Nevertheless, homozygous mice harboring the Scn5a-p.Y1981N mutation showed no electrophysiological alterations nor changes in AP or (late) INa properties, questioning the in vivo relevance of the PY-motif. Our findings suggest the presence of compensatory mechanisms, with additional, as yet unknown, factors likely required to reduce the “ubiquitylation reserve” of Nav1.5. Future identification of such modulatory factors may identify potential triggers for arrhythmias and sudden cardiac death in the setting of LQT3 mutations.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/1422-0067/20/20/5033Test; https://doaj.org/toc/1422-0067Test

الوصول الحر: https://doaj.org/article/303d9d696c274f688ffc404464157d77Test

المؤلفون: Vincent Portero, Ronald Wilders, Simona Casini, Flavien Charpentier, Arie O. Verkerk, Carol Ann Remme

المصدر: Frontiers in Physiology, Vol 9 (2018)

مصطلحات موضوعية: transient outward current, sodium current, channels, action potential, myocyte, arrhythmias, Physiology, QP1-981

الوصف: In cardiomyocytes, the voltage-gated transient outward potassium current (Ito) is responsible for the phase-1 repolarization of the action potential (AP). Gain-of-function mutations in KCND3, the gene encoding the Ito carrying KV4.3 channel, have been associated with Brugada syndrome (BrS). While the role of Ito in the pro-arrhythmic mechanism of BrS has been debated, recent studies have suggested that an increased Ito may directly affect cardiac conduction. However, the effects of an increased Ito on AP upstroke velocity or sodium current at the cellular level remain unknown. We here investigated the consequences of KV4.3 overexpression on NaV1.5 current and consequent sodium channel availability. We found that overexpression of KV4.3 protein in HEK293 cells stably expressing NaV1.5 (HEK293-NaV1.5 cells) significantly reduced NaV1.5 current density without affecting its kinetic properties. In addition, KV4.3 overexpression decreased AP upstroke velocity in HEK293-NaV1.5 cells, as measured with the alternating voltage/current clamp technique. These effects of KV4.3 could not be explained by alterations in total NaV1.5 protein expression. Using computer simulations employing a multicellular in silico model, we furthermore demonstrate that the experimentally observed increase in KV4.3 current and concurrent decrease in NaV1.5 current may result in a loss of conduction, underlining the potential functional relevance of our findings. This study gives the first proof of concept that KV4.3 directly impacts on NaV1.5 current. Future studies employing appropriate disease models should explore the potential electrophysiological implications in (patho)physiological conditions, including BrS associated with KCND3 gain-of-function mutations.

وصف الملف: electronic resource

العلاقة: http://journal.frontiersin.org/article/10.3389/fphys.2018.00178/fullTest; https://doaj.org/toc/1664-042XTest

الوصول الحر: https://doaj.org/article/98919b467e3f400e9fde754b76f49b31Test

المؤلفون: Vincent Portero, Solena Le Scouarnec, Zeineb Es‐Salah‐Lamoureux, Sophie Burel, Jean‐Baptiste Gourraud, Stéphanie Bonnaud, Pierre Lindenbaum, Floriane Simonet, Jade Violleau, Estelle Baron, Eléonore Moreau, Carol Scott, Stéphanie Chatel, Gildas Loussouarn, Thomas O'Hara, Philippe Mabo, Christian Dina, Hervé Le Marec, Jean‐Jacques Schott, Vincent Probst, Isabelle Baró, Céline Marionneau, Flavien Charpentier, Richard Redon

المصدر: Journal of the American Heart Association: Cardiovascular and Cerebrovascular Disease, Vol 5, Iss 6 (2016)

مصطلحات موضوعية: Brugada syndrome, cardiac arrhythmia, clinical electrophysiology, genetics, KCNAB2/Kvβ2, potassium ion channels, Diseases of the circulatory (Cardiovascular) system, RC666-701

الوصف: BackgroundThe Brugada syndrome is an inherited cardiac arrhythmia associated with high risk of sudden death. Although 20% of patients with Brugada syndrome carry mutations in SCN5A, the molecular mechanisms underlying this condition are still largely unknown. Methods and ResultsWe combined whole‐exome sequencing and linkage analysis to identify the genetic variant likely causing Brugada syndrome in a pedigree for which SCN5A mutations had been excluded. This approach identified 6 genetic variants cosegregating with the Brugada electrocardiographic pattern within the pedigree. In silico gene prioritization pointed to 1 variant residing in KCNAB2, which encodes the voltage‐gated K+ channel β2‐subunit (Kvβ2‐R12Q). Kvβ2 is widely expressed in the human heart and has been shown to interact with the fast transient outward K+ channel subunit Kv4.3, increasing its current density. By targeted sequencing of the KCNAB2 gene in 167 unrelated patients with Brugada syndrome, we found 2 additional rare missense variants (L13F and V114I). We then investigated the physiological effects of the 3 KCNAB2 variants by using cellular electrophysiology and biochemistry. Patch‐clamp experiments performed in COS‐7 cells expressing both Kv4.3 and Kvβ2 revealed a significant increase in the current density in presence of the R12Q and L13F Kvβ2 mutants. Although biotinylation assays showed no differences in the expression of Kv4.3, the total and submembrane expression of Kvβ2‐R12Q were significantly increased in comparison with wild‐type Kvβ2. ConclusionsAltogether, our results indicate that Kvβ2 dysfunction can contribute to the Brugada electrocardiographic pattern.

وصف الملف: electronic resource

العلاقة: https://doaj.org/toc/2047-9980Test

الوصول الحر: https://doaj.org/article/b67e2535b2574e7c940289a9f00f97eaTest

المؤلفون: Camille Rolland-Debord, David Lair, Tiphaine Roussey-Bihouée, Dorian Hassoun, Justine Evrard, Marie-Aude Cheminant, Julie Chesné, Faouzi Braza, Guillaume Mahay, Vincent Portero, Christine Sagan, Bruno Pitard, Antoine Magnan

المصدر: PLoS ONE, Vol 9, Iss 1, p e85976 (2014)

مصطلحات موضوعية: Medicine, Science

الوصف: BackgroundAllergic asthma is caused by abnormal immunoreactivity against allergens such as house dust mites among which Dermatophagoides farinae (Der f) is a common species. Currently, immunotherapy is based on allergen administration, which has variable effect from patient to patient and may cause serious side effects, principally the sustained risk of anaphylaxis. DNA vaccination is a promising approach by triggering a specific immune response with reduced allergenicity.ObjectiveThe aim of the study is to evaluate the effects of DNA immunization with Der f1 allergen specific DNA on allergic sensitization, inflammation and respiratory function in mice.MethodsMice were vaccinated 28 and 7 days before allergen exposure with a Der f1-encoding plasmid formulated with a block copolymer. Asthma was induced by skin sensitization followed by intra-nasal challenges with Der f extract. Total lung, broncho-alveolar lavage (BAL) and spleen cells were analyzed by flow cytometry for their surface antigen and cytokine expression. Splenocytes and lung cell IFN-γ production by CD8+ cells in response to Der f CMH1-restricted peptides was assessed by ELISPOT. IgE, IgG1 and IgG2a were measured in serum by ELISA. Specific bronchial hyperresponsiveness was assessed by direct resistance measurements.ResultsCompared to animals vaccinated with an irrelevant plasmid, pVAX-Der f1 vaccination induced an increase of B cells in BAL, and an elevation of IL-10 and IFN-γ but also of IL-4, IL-13 and IL-17 producing CD4+ lymphocytes in lungs and of IL-4 and IL-5 in spleen. In response to CD8-restricted peptides an increase of IFN-γ was observed among lung cells. IgG2a levels non-specifically increased following block copolymer/DNA vaccination although IgE, IgG1 levels and airways resistances were not impacted.Conclusions & clinical relevanceDNA vaccination using a plasmid coding for Der f1 formulated with the block copolymer 704 induces a specific immune response in the model of asthma used herein.

وصف الملف: electronic resource

العلاقة: https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/24497934/pdf/?tool=EBITest; https://doaj.org/toc/1932-6203Test

الوصول الحر: https://doaj.org/article/6b1f31557e3143d0a1b8ff42dd6b6c3eTest

المؤلفون: Gerard A Marchal, Niels Galjart, Vincent Portero, Carol Ann Remme

المصدر: Cardiovascular Research.

مصطلحات موضوعية: Physiology, Physiology (medical), Cardiology and Cardiovascular Medicine

الوصف: The cardiac sodium channel NaV1.5 is an essential modulator of cardiac excitability, with decreased NaV1.5 levels at the plasma membrane and consequent reduction in sodium current (INa) leading to potentially lethal cardiac arrhythmias. NaV1.5 is distributed in a specific pattern at the plasma membrane of cardiomyocytes, with localization at the crests, grooves, and T-tubules of the lateral membrane and particularly high levels at the intercalated disc region. NaV1.5 forms a large macromolecular complex with and is regulated by interacting proteins, some of which are specifically localized at either the lateral membrane or intercalated disc. One of the NaV1.5 trafficking routes is via microtubules (MTs), which are regulated by MT plus-end tracking proteins (+TIPs). In our search for mechanisms involved in targeted delivery of NaV1.5, we here provide an overview of previously demonstrated interactions between NaV1.5 interacting proteins and +TIPs, which potentially (in)directly impact on NaV1.5 trafficking. Strikingly, +TIPs interact extensively with several intercalated disc- and lateral membrane-specific NaV1.5 interacting proteins. Recent work indicates that this interplay of +TIPs and NaV1.5 interacting proteins mediates the targeted delivery of NaV1.5 at specific cardiomyocyte subcellular domains, while also being potentially relevant for the trafficking of other ion channels. These observations are especially relevant for diseases associated with loss of NaV1.5 specifically at the lateral membrane (such as Duchenne muscular dystrophy), or at the intercalated disc (for example, arrhythmogenic cardiomyopathy), and open up potential avenues for development of new anti-arrhythmic therapies.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_________::b3bf5e02d5bf7f4b71976480dcdd425aTest
https://doi.org/10.1093/cvr/cvad052Test

المؤلفون: Simona Casini, Vincent Portero, Gerard A Marchal, Carol Ann Remme, Joris R. de Groot, Fransisca A. Nariswari, Kaomei Guan, Antoine H.G. Driessen, Marieke W. Veldkamp, Arie O. Verkerk, Makiri Kawasaki, Nicoline W.E. van den Berg, Isabella Mengarelli

المساهمون: Cardiology, ACS - Heart failure & arrhythmias, Graduate School, Cardiothoracic Surgery, ACS - Pulmonary hypertension & thrombosis, Medical Biology, ACS - Amsterdam Cardiovascular Sciences, APH - Methodology

المصدر: Cardiovascular Drugs and Therapy
Cardiovascular drugs and therapy / sponsored by the International Society of Cardiovascular Pharmacotherapy, 33(6), 649-660. Kluwer Academic Publishers

مصطلحات موضوعية: Male, 0301 basic medicine, Action Potentials, SCN10A/Na 1.8, 030204 cardiovascular system & hematology, 0302 clinical medicine, Left atrial, Atrial Fibrillation, Medicine, Myocytes, Cardiac, Pharmacology (medical), health care economics and organizations, Cardiomyocytes, Voltage-Gated Sodium Channel Blockers, Membrane potential, Sodium channel, Cardiac electrophysiology, General Medicine, cardiovascular system, Cardiology, SCN10A/Nav1.8, Action potential duration, Original Article, Rabbits, Electrophysiologic Techniques, Cardiac, Cardiology and Cardiovascular Medicine, medicine.medical_specialty, Cell type, Heart Ventricles, Induced Pluripotent Stem Cells, Cell Line, Sodium current, NAV1.8 Voltage-Gated Sodium Channel, 03 medical and health sciences, Species Specificity, health services administration, Late sodium current, Internal medicine, Animals, Humans, Atrial Appendage, Heart Atria, Pharmacology, hiPSC-CMs, business.industry, Atrial tissue, Kinetics, 030104 developmental biology, NAV1, business, Patch-clamp

الوصف: Purpose Several studies have indicated a potential role for SCN10A/NaV1.8 in modulating cardiac electrophysiology and arrhythmia susceptibility. However, by which mechanism SCN10A/NaV1.8 impacts on cardiac electrical function is still a matter of debate. To address this, we here investigated the functional relevance of NaV1.8 in atrial and ventricular cardiomyocytes (CMs), focusing on the contribution of NaV1.8 to the peak and late sodium current (INa) under normal conditions in different species. Methods The effects of the NaV1.8 blocker A-803467 were investigated through patch-clamp analysis in freshly isolated rabbit left ventricular CMs, human left atrial CMs and human-induced pluripotent stem cell-derived CMs (hiPSC-CMs). Results A-803467 treatment caused a slight shortening of the action potential duration (APD) in rabbit CMs and hiPSC-CMs, while it had no effect on APD in human atrial cells. Resting membrane potential, action potential (AP) amplitude, and AP upstroke velocity were unaffected by A-803467 application. Similarly, INa density was unchanged after exposure to A-803467 and NaV1.8-based late INa was undetectable in all cell types analysed. Finally, low to absent expression levels of SCN10A were observed in human atrial tissue, rabbit ventricular tissue and hiPSC-CMs. Conclusion We here demonstrate the absence of functional NaV1.8 channels in non-diseased atrial and ventricular CMs. Hence, the association of SCN10A variants with cardiac electrophysiology observed in, e.g. genome wide association studies, is likely the result of indirect effects on SCN5A expression and/or NaV1.8 activity in cell types other than CMs.

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e7b4ef2ce4fb577a5fa2c0e1f680be0cTest
https://doi.org/10.1007/s10557-019-06925-6Test

المؤلفون: Mischa Klerk, Calum A. MacRae, Marta Pérez-Hernández, Elisabeth M. Lodder, Paul W. Burridge, Christiaan C. Veerman, Isabella Mengarelli, Richard Redon, Vincent Portero, Gerard A Marchal, Carol Ann Remme, Mario Delmar, Franck Potet, Flavien Charpentier, Kaomei Guan, Svitlana Podliesna, Nuo Yu, Carlos G. Vanoye, Alfred Lewis George, David Y. Chiang, Niels Galjart, Simona Casini, Mariam Jouni, Arie O. Verkerk, Eli Rothenberg, Connie R. Bezzina

المساهمون: Cardiology, Graduate School, ACS - Heart failure & arrhythmias, Human Genetics, Medical Biology, APH - Methodology, Cell biology

المصدر: Circ Res
Circulation research, 129(3), 349-365. Lippincott Williams and Wilkins
Circulation Research, 129(3), 349-365. Lippincott Williams & Wilkins

مصطلحات موضوعية: biology, Physiology, Chemistry, cardiac, Sodium channel, Myocardium, Fluorescence recovery after photobleaching, Nav1.5, biology.organism_classification, electrophysiology, zebrafish, Article, Sodium Channels, Cell biology, Microtubule, Cytoplasm, GSK-3, biology.protein, microscopy, Cardiology and Cardiovascular Medicine, Induced pluripotent stem cell, Zebrafish, myocyte, cardiac, myocyte, microtubule

الوصف: Rationale: Loss-of-function of the cardiac sodium channel Na V 1.5 causes conduction slowing and arrhythmias. Na V 1.5 is differentially distributed within subcellular domains of cardiomyocytes, with sodium current ( I Na ) being enriched at the intercalated discs (ID). Various pathophysiological conditions associated with lethal arrhythmias display ID-specific I Na reduction, but the mechanisms underlying microdomain-specific targeting of Na V 1.5 remain largely unknown. Objective: To investigate the role of the microtubule plus-end tracking proteins EB1 (end-binding protein 1) and CLASP2 (cytoplasmic linker associated protein 2) in mediating Na V 1.5 trafficking and subcellular distribution in cardiomyocytes. Methods and Results: EB1 overexpression in human-induced pluripotent stem cell-derived cardiomyocytes resulted in enhanced whole-cell I Na , increased action potential upstroke velocity ( V max ), and enhanced Na V 1.5 localization at the plasma membrane as detected by multicolor stochastic optical reconstruction microscopy. Fluorescence recovery after photobleaching experiments in HEK293A cells demonstrated that EB1 overexpression promoted Na V 1.5 forward trafficking. Knockout of MAPRE1 in human induced pluripotent stem cell-derived cardiomyocytes led to reduced whole-cell I Na , decreased V max , and action potential duration (APD) prolongation. Similarly, acute knockout of the MAPRE1 homolog in zebrafish ( mapre1b ) resulted in decreased ventricular conduction velocity and V max as well as increased APD. Stochastic optical reconstruction microscopy imaging and macropatch I Na measurements showed that subacute treatment (2–3 hours) with SB216763 (SB2), a GSK3β (glycogen synthase kinase 3β) inhibitor known to modulate CLASP2-EB1 interaction, reduced GSK3β localization and increased Na V 1.5 and I Na preferentially at the ID region of wild-type murine ventricular cardiomyocytes. By contrast, SB2 did not affect whole cell I Na or Na V 1.5 localization in cardiomyocytes from Clasp2 -deficient mice, uncovering the crucial role of CLASP2 in SB2-mediated modulation of Na V 1.5 at the ID. Conclusions: Our findings demonstrate the modulatory effect of the microtubule plus-end tracking protein EB1 on Na V 1.5 trafficking and function, and identify the EB1-CLASP2 complex as a target for preferential modulation of I Na within the ID region of cardiomyocytes.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e4ec730de2a7e331c928f42d1d495887Test
https://europepmc.org/articles/PMC8298292Test/

المؤلفون: Leander Beekman, Carol Ann Remme, Vincent Portero, Gerard A Marchal, Rafik Tadros, Arie O. Verkerk, A Blease, Paul Potter, I. Jane Cox, Svitlana Podliesna, Simona Casini, Gabi Kastenmüller, Christian Gieger, T Nicol, Tertius Hough, Moritz F. Sinner, Stefan Kääb, Annette Peters, Connie R. Bezzina, Martina Müller-Nurasyid, Michael W.T. Tanck, Sara Falcone, Jorien L. Treur, Antonius Baartscheer, Fay Probert

المساهمون: Epidemiology and Data Science, APH - Methodology, Physiology, Cardiology, ACS - Heart failure & arrhythmias, Graduate School, Adult Psychiatry, ANS - Amsterdam Neuroscience, ACS - Amsterdam Cardiovascular Sciences, Medical Biology

المصدر: Cardiovascular Research, 118(7), 1742-1757. Oxford University Press
Cardiovasc. Res. 118:1742–1757 (2021)
Cardiovascular research, 118(7), 1742-1757. Oxford University Press
Portero, V, Nicol, T, Podliesna, S, Marchal, G A, Baartscheer, A, Casini, S, Tadros, R, Treur, J L, Tanck, M W T, Jane Cox, I J, Probert, F, Hough, T A, Falcone, S, Beekman, L, Müller-Nurasyid, M, Kastenmüller, G, Gieger, C, Peters, A, Kääb, S, Sinner, M F, Blease, A, Verkerk, A O, Bezzina, C R, Potter, P K & Remme, C A 2022, ' Chronically elevated branched chain amino acid levels are pro-arrhythmic ', Cardiovascular Research, vol. 118, no. 7, pp. 1742-1757 . https://doi.org/10.1093/cvr/cvab207Test

مصطلحات موضوعية: 0301 basic medicine, medicine.medical_specialty, Physiology, Branched-chain amino acid, 030204 cardiovascular system & hematology, Sudden death, Sudden cardiac death, Afterdepolarization, 03 medical and health sciences, chemistry.chemical_compound, Mice, 0302 clinical medicine, Physiology (medical), Internal medicine, Cardiac conduction, medicine, Animals, Humans, Myocytes, Cardiac, BCAA, Arrhythmia, Bcaa, Electrophysiology, Metabolism, Sudden Death, Heart Failure, Sirolimus, business.industry, Cardiac arrhythmia, medicine.disease, 030104 developmental biology, Endocrinology, chemistry, Heart failure, Calcium, Metabolic syndrome, Cardiology and Cardiovascular Medicine, business, Amino Acids, Branched-Chain

الوصف: Aim. Cardiac arrhythmias comprise a major health and economic burden and are associated with significant morbidity and mortality, including cardiac failure, stroke and sudden cardiac death (SCD). Development of efficient preventive and therapeutic strategies is hampered by incomplete knowledge of disease mechanisms and pathways. Our aim is to identify novel mechanisms underlying cardiac arrhythmia and SCD using an unbiased approach. Methods and Results. We employed a phenotype-driven N-ethyl-N-nitrosourea (ENU) mutagenesis screen and identified a mouse line with a high incidence of sudden death at young age (6-9 weeks) in the absence of prior symptoms. Affected mice were found to be homozygous for the nonsense mutation Bcat2p.Q300*/p.Q300* in the Bcat2 gene encoding branched chain amino acid transaminase 2. At the age of 4-5 weeks, Bcat2p.Q300*/p.Q300* mice displayed drastic increase of plasma levels of branch chain amino acids (BCAAs – leucine, isoleucine, valine) due to the incomplete catabolism of BCAAs, in addition to inducible arrhythmias ex vivo as well as cardiac conduction and repolarization disturbances. In line with these findings, plasma BCAA levels were positively correlated to ECG indices of conduction and repolarization in the German community-based KORA F4 Study. Isolated cardiomyocytes from Bcat2p.Q300*/p.Q300* mice revealed action potential (AP) prolongation, pro-arrhythmic events (early and late afterdepolarizations, triggered APs) and dysregulated calcium homeostasis. Incubation of human pluripotent stem cell-derived cardiomyocytes with elevated concentration of BCAAs induced similar calcium dysregulation and pro-arrhythmic events which were prevented by rapamycin, demonstrating the crucial involvement of mTOR pathway activation. Conclusions. Our findings identify for the first time a causative link between elevated BCAAs and arrhythmia, which has implications for arrhythmogenesis in conditions associated with BCAA metabolism dysregulation such as diabetes, metabolic syndrome and heart failure. Translational perspectives. Development of efficient anti-arrhythmic strategies is hampered by incomplete knowledge of disease mechanisms. Using an unbiased approach, we here identified for the first time a pro-arrhythmic effect of increased levels of branched chain amino acids (BCAAs). This is of particular relevance for conditions associated with BCAA dysregulation and increased arrhythmia risk, including heart failure, obesity and diabetes, as well as for athletes supplementing their diet with BCAAs. Such metabolic dysregulation is potentially modifiable through dietary interventions, paving the way for novel preventive strategies. Our findings furthermore identify mTOR inhibition as a potential anti-arrhythmic strategy in patients with metabolic syndrome.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::751f09554e89397bd6ba435a96e8ba26Test
https://pubmed.ncbi.nlm.nih.gov/34142125Test

المؤلفون: Frits A. Wijburg, Connie R. Bezzina, Suzan J. G. Knottnerus, Xiaojing Luo, Antonius Baartscheer, Kaomei Guan, Wener Li, Sacha Ferdinandusse, Ronald J.A. Wanders, Ying Ulbricht, Rob C. I. Wüst, Riekelt H. Houtkooper, Isabella Mengarelli, Gepke Visser, Ruben Coronel, Vincent Portero, Jeannette C. Bleeker, Lodewijk IJlst, Arie O. Verkerk

المساهمون: Graduate School, Laboratory Genetic Metabolic Diseases, AGEM - Endocrinology, metabolism and nutrition, AGEM - Inborn errors of metabolism, Cardiology, ACS - Heart failure & arrhythmias, ACS - Diabetes & metabolism, AMS - Ageing & Morbidty, Laboratory for General Clinical Chemistry, Paediatric Metabolic Diseases, Medical Biology, ACS - Amsterdam Cardiovascular Sciences, ARD - Amsterdam Reproduction and Development, APH - Methodology, APH - Aging & Later Life

المصدر: International journal of molecular sciences, 21(7):2589. Multidisciplinary Digital Publishing Institute (MDPI)
International Journal of Molecular Sciences, Vol 21, Iss 2589, p 2589 (2020)
International Journal of Molecular Sciences
Volume 21
Issue 7

مصطلحات موضوعية: 0301 basic medicine, Mitochondrial Diseases, Action Potentials, 030204 cardiovascular system & hematology, Resveratrol, Mitochondrion, Arrhythmias, hiPSC, lcsh:Chemistry, chemistry.chemical_compound, 0302 clinical medicine, Congenital Bone Marrow Failure Syndromes, Myocytes, Cardiac, Induced pluripotent stem cell, Beta oxidation, lcsh:QH301-705.5, Spectroscopy, health care economics and organizations, chemistry.chemical_classification, Chemistry, Acyl-CoA Dehydrogenase, Long-Chain, Fatty Acids, General Medicine, Computer Science Applications, Mitochondria, VLCADD, Oxidation-Reduction, Intracellular, Acylcarnitines, medicine.medical_specialty, Induced Pluripotent Stem Cells, Catalysis, Lipid Metabolism, Inborn Errors, Article, Inorganic Chemistry, 03 medical and health sciences, Muscular Diseases, Internal medicine, medicine, Humans, Physical and Theoretical Chemistry, Molecular Biology, Organic Chemistry, Fatty acid, Arrhythmias, Cardiac, 030104 developmental biology, Endocrinology, lcsh:Biology (General), lcsh:QD1-999, Epoxy Compounds, Cardiac Electrophysiology, Biogenesis, Etomoxir

الوصف: Patients with very long-chain acyl-CoA dehydrogenase deficiency (VLCADD) can present with life-threatening cardiac arrhythmias. The pathophysiological mechanism is unknown. We reprogrammed fibroblasts from one mildly and one severely affected VLCADD patient, into human induced pluripotent stem cells (hiPSCs) and differentiated these into cardiomyocytes (VLCADD-CMs). VLCADD-CMs displayed shorter action potentials (APs), more delayed afterdepolarizations (DADs) and higher systolic and diastolic intracellular Ca2+ concentration ([Ca2+]i) than control CMs. The mitochondrial booster resveratrol mitigated the biochemical, electrophysiological and [Ca2+]i changes in the mild but not in the severe VLCADD-CMs. Accumulation of potentially toxic intermediates of fatty acid oxidation was blocked by substrate reduction with etomoxir. Incubation with etomoxir led to marked prolongation of AP duration and reduced DADs and [Ca2+]i in both VLCADD-CMs. These results provide compelling evidence that reduced accumulation of fatty acid oxidation intermediates, either by enhanced fatty acid oxidation flux through increased mitochondria biogenesis (resveratrol) or by inhibition of fatty acid transport into the mitochondria (etomoxir), rescues pro-arrhythmia defects in VLCADD-CMs and open doors for new treatments.

وصف الملف: application/pdf

الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::1048994c1c7de653958d78caa5e5c907Test
https://pure.amc.nl/en/publications/electrophysiological-abnormalities-in-vlcad-deficient-hipsccardiomyocytes-can-be-improved-by-lowering-accumulation-of-fatty-acid-oxidation-intermediatesTest(7408927f-4407-47ac-bfe0-fd5a7be0c915).html