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Huang M, Wang X, Chen Y, Pessoa MT, Terrell KC, Zhang J, Tian J, Xie Z, Pierre SV, Cai L. Role of Na/K-ATPase α1 caveolin-binding motif in adipogenesis. Am J Physiol Cell Physiol 2024; 327:C48-C64. [PMID: 38708522 DOI: 10.1152/ajpcell.00168.2024] [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: 03/14/2024] [Revised: 04/28/2024] [Accepted: 04/29/2024] [Indexed: 05/07/2024]
Abstract
Deficiencies in mice and in humans have brought to the fore the importance of the caveolar network in key aspects of adipocyte biology. The conserved N-terminal caveolin-binding motif (CBM) of the ubiquitous Na/K-ATPase (NKA) α1 isoform, which allows NKA/caveolin-1 (Cav1) interaction, influences NKA signaling and caveolar distribution. It has been shown to be critical for animal development and ontogenesis, as well as lineage-specific differentiation of human induced pluripotent stem cells (hiPSCs). However, its role in postnatal adipogenesis has not been fully examined. Using a genetic approach to alter CBM in hiPSC-derived adipocytes (iAdi-mCBM) and in mice (mCBM), we investigated the regulatory function of NKA CBM signaling in adipogenesis. Seahorse XF cell metabolism analyses revealed impaired glycolysis and decreased ATP synthesis-coupled respiration in iAdi-mCBM. These metabolic dysfunctions were accompanied by evidence of extensive remodeling of the extracellular matrix (ECM), including increased collagen staining, overexpression of ECM marker genes, and heightened TGF-β signaling uncovered by RNAseq analysis. Rescue of mCBM by lentiviral delivery of WT NKA α1 or treatment of mCBM hiPSCs with the TGF-β inhibitor SB431542 normalized ECM, suggesting that NKA CBM signaling integrity is required for adequate control of TGF-β signaling and ECM stiffness during adipogenesis. The physiological impact was revealed in mCBM male mice with reduced fat mass accompanied by histological and transcriptional evidence of elevated adipose fibrosis and decreased adipocyte size. Based on these findings, we propose that the genetic alteration of the NKA/Cav1 regulatory path uncovered in human iAdi leads to lipodystrophy in mice.NEW & NOTEWORTHY A Na/K-ATPase α1 caveolin-binding motif regulates adipogenesis. Mutation of this binding motif in the mouse leads to reduced fat with increased extracellular matrix production and inflammation. RNA-seq analysis and pharmacological interventions in human iPSC-derived adipocytes revealed that TGF-β signal, rather than Na/K-ATPase-mediated ion transport, is a key mediator of NKA regulation of adipogenesis.
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Affiliation(s)
- Minqi Huang
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States
| | - Xiaoliang Wang
- Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia, United States
| | - Yiliang Chen
- Versiti Blood Research Institute, Milwaukee, West Virginia, United States
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Marco T Pessoa
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States
| | - Kayleigh C Terrell
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States
| | - Jue Zhang
- Versiti Blood Research Institute, Milwaukee, West Virginia, United States
- Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Jiang Tian
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States
- Joan C. Edwards School of Medicine, Marshall University, Huntington, West Virginia, United States
| | - Zijian Xie
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States
| | - Sandrine V Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States
| | - Liquan Cai
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States
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2
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Obradovic M, Sudar-Milovanovic E, Gluvic Z, Banjac K, Rizzo M, Isenovic ER. The Na +/K +-ATPase: A potential therapeutic target in cardiometabolic diseases. Front Endocrinol (Lausanne) 2023; 14:1150171. [PMID: 36926029 PMCID: PMC10011626 DOI: 10.3389/fendo.2023.1150171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 02/14/2023] [Indexed: 03/08/2023] Open
Abstract
Cardiometabolic diseases (CMD) are a direct consequence of modern living and contribute to the development of multisystem diseases such as cardiovascular diseases and diabetes mellitus (DM). CMD has reached epidemic proportions worldwide. A sodium pump (Na+/K+-ATPase) is found in most eukaryotic cells' membrane and controls many essential cellular functions directly or indirectly. This ion transporter and its isoforms are important in the pathogenesis of some pathological processes, including CMD. The structure and function of Na+/K+-ATPase, its expression and distribution in tissues, and its interactions with known ligands such as cardiotonic steroids and other suspected endogenous regulators are discussed in this review. In addition, we reviewed recent literature data related to the involvement of Na+/K+-ATPase activity dysfunction in CMD, focusing on the Na+/K+-ATPase as a potential therapeutic target in CMD.
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Affiliation(s)
- Milan Obradovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Emina Sudar-Milovanovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Zoran Gluvic
- University Clinical-Hospital Centre Zemun-Belgrade, Clinic of Internal medicine, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Katarina Banjac
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Manfredi Rizzo
- School of Medicine, Promise Department, University of Palermo, Palermo, Italy
- *Correspondence: Manfredi Rizzo,
| | - Esma R. Isenovic
- Department of Radiobiology and Molecular Genetics, “VINČA“ Institute of Nuclear Sciences - National Institute of thе Republic of Serbia, University of Belgrade, Belgrade, Serbia
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3
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Leite JA, Cavalcante-Silva LHA, Ribeiro MR, de Morais Lima G, Scavone C, Rodrigues-Mascarenhas S. Neuroinflammation and Neutrophils: Modulation by Ouabain. Front Pharmacol 2022; 13:824907. [PMID: 35173621 PMCID: PMC8841582 DOI: 10.3389/fphar.2022.824907] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/10/2022] [Indexed: 12/12/2022] Open
Abstract
Cardiotonic steroids are natural compounds that present many physiological and pharmacological functions. They bind Na+/K+-ATPase (NKA) modifying cellular ion concentration and trigger cell signaling mechanisms without altering ion balance. These steroids are known to modulate some immune responses, including cytokine production, neutrophil migration, and inflammation (peripherally and in the nervous system). Inflammation can occur in response to homeostasis perturbations and is related to the development of many diseases, including immune-mediated diseases and neurodegenerative disorders. Considering the neutrophils role in the general neuroinflammatory response and that these cells can be modulated by cardiac steroids, this work aims to review the possible regulation of neutrophilic neuroinflammation by the cardiac steroid ouabain.
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Affiliation(s)
- Jacqueline Alves Leite
- Department of Pharmacology, Institute of Biomedical Science, Federal University of Goiás, Goiânia, Brazil
| | | | - Martina Raissa Ribeiro
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Geovanni de Morais Lima
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
- *Correspondence: Cristoforo Scavone,
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4
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Citterio L, Bianchi G, Scioli GA, Glorioso N, Bigazzi R, Cusi D, Staessen JA, Cavuto S, Ferrandi M, Lanzani C, Li X, Lau LF, Chiang CE, Wang TD, Wang KL, Ferrari P, Manunta P. Antihypertensive treatment guided by genetics: PEARL-HT, the randomized proof-of-concept trial comparing rostafuroxin with losartan. THE PHARMACOGENOMICS JOURNAL 2021; 21:346-358. [PMID: 33649520 PMCID: PMC8159753 DOI: 10.1038/s41397-021-00214-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 01/14/2021] [Accepted: 01/27/2021] [Indexed: 12/22/2022]
Abstract
We compared a standard antihypertensive losartan treatment with a pharmacogenomics-guided rostafuroxin treatment in never-treated Caucasian and Chinese patients with primary hypertension. Rostafuroxin is a digitoxigenin derivative that selectively disrupts the binding to the cSrc-SH2 domain of mutant α-adducin and of the ouabain-activated Na-K pump at 10-11 M. Of 902 patients screened, 172 were enrolled in Italy and 107 in Taiwan. After stratification for country and genetic background, patients were randomized to rostafuroxin or losartan, being the difference in the fall in office systolic blood pressure (OSBP) after 2-month treatment the primary endpoint. Three pharmacogenomic profiles (P) were examined, considering: P1, adding to the gene variants included in the subsequent P2, the variants detected by post-hoc analysis of a previous trial; P2, variants of genes encoding enzymes for endogenous ouabain (EO) synthesis (LSS and HSD3B1), EO transport (MDR1/ABCB1), adducin (ADD1 and ADD3); P3, variants of the LSS gene only. In Caucasians, the group differences (rostafuroxin 50 μg minus losartan 50 mg in OSBP mmHg) were significant both in P2 adjusted for genetic heterogeneity (P2a) and P3 LSS rs2254524 AA [9.8 (0.6-19.0), P = 0.038 and 13.4 (25.4-2.5), P = 0.031, respectively]. In human H295R cells transfected with LSS A and LSS C variants, the EO production was greater in the former (P = 0.038); this difference was abolished by rostafuroxin at 10-11 M. Chinese patients had a similar drop in OSBP to Caucasians with losartan but no change in OSBP with rostafuroxin. These results show that genetics may guide drug treatment for primary hypertension in Caucasians.
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Affiliation(s)
- Lorena Citterio
- Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Università Vita Salute San Raffaele, Milano, Italy.,Università Vita Salute San Raffaele, Milan, Italy
| | | | - Giuseppe A Scioli
- Hypertension and Cardiovascular Prevention Center, Ospedale Ferdinando Veneziale, Isernia, Italy
| | - Nicola Glorioso
- Hypertension and Related Diseases Center, Department of Clinical and Experimental Medicine, University of Sassari, Sassari, Italy
| | | | - Daniele Cusi
- Institute of Biomedical Technologies Milano National Research Council of Italy (CNR), Segrate, Milano, Italy.,Bio4Dreams Scientific Unit, Bio4Dreams-Business Nursery for Life Sciences, Milano, Italy
| | - Jan A Staessen
- Research Unit Hypertension and Cardiovascular Epidemiology KU Leuven Department of Cardiovascular Sciences, University of Leuven, Leuven, Belgium
| | - Silvio Cavuto
- Clinical Trials and Statistics Unit, Azienda USL-IRCCS di Reggio Emilia, Reggio Emilia, Italy
| | | | - Chiara Lanzani
- Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Università Vita Salute San Raffaele, Milano, Italy.,Università Vita Salute San Raffaele, Milan, Italy
| | | | - Lit-Fui Lau
- Zhaoke (Guangzhou) Ophthalmology Pharmaceutical Limited, Guangzhou, China
| | - Chern-En Chiang
- General Clinical Research Center, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | - Tzung-Dau Wang
- Cardiovascular Center and Division of Cardiology, Department of Internal Medicine, National Taiwan University Hospital and College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kang-Ling Wang
- General Clinical Research Center, Taipei Veterans General Hospital and National Yang-Ming University, Taipei, Taiwan
| | | | - Paolo Manunta
- Genomics of Renal Diseases and Hypertension Unit, IRCCS San Raffaele Scientific Institute, Università Vita Salute San Raffaele, Milano, Italy.,Università Vita Salute San Raffaele, Milan, Italy
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5
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Fan X, Gao Y, Zhang X, Lughmani HY, Kennedy DJ, Haller ST, Pierre SV, Shapiro JI, Tian J. A strategic expression method of miR-29b and its anti-fibrotic effect based on RNA-sequencing analysis. PLoS One 2020; 15:e0244065. [PMID: 33332475 PMCID: PMC7746150 DOI: 10.1371/journal.pone.0244065] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/02/2020] [Indexed: 02/07/2023] Open
Abstract
Tissue fibrosis is a significant health issue associated with organ dysfunction and failure. Increased deposition of collagen and other extracellular matrix (ECM) proteins in the interstitial area is a major process in tissue fibrosis. The microRNA-29 (miR-29) family has been demonstrated as anti-fibrotic microRNAs. Our recent work showed that dysregulation of miR-29 contributes to the formation of cardiac fibrosis in animal models of uremic cardiomyopathy, whereas replenishing miR-29 attenuated cardiac fibrosis in these animals. However, excessive overexpression of miR-29 is a concern because microRNAs usually have multiple targets, which could result in unknown and unexpected side effect. In the current study, we constructed a novel Col1a1-miR-29b vector using collagen 1a1 (Col1a1) promoter, which can strategically express miR-29b-3p (miR-29b) in response to increased collagen synthesis and reach a dynamic balance between collagen and miR-29b. Our experimental results showed that in mouse embryonic fibroblasts (MEF cells) transfected with Col1a1-miR-29b vector, the miR-29b expression is about 1000 times less than that in cells transfected with CMV-miR-29b vector, which uses cytomegalovirus (CMV) as a promoter for miR-29b expression. Moreover, TGF-β treatment increased the miR-29b expression by about 20 times in cells transfected with Col1a1-miR-29b, suggesting a dynamic response to fibrotic stimulation. Western blot using cell lysates and culture media demonstrated that transfection of Col1a1-miR-29b vector significantly reduced TGF-β induced collagen synthesis and secretion, and the effect was as effective as the CMV-miR-29b vector. Using RNA-sequencing analysis, we found that 249 genes were significantly altered (180 upregulated and 69 downregulated, at least 2-fold change and adjusted p-value <0.05) after TGF-β treatment in MEF cells transfected with empty vector. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis using GAGE R-package showed that the top 5 upregulated pathways after TGF-β treatment were mostly fibrosis-related, including focal adhesion, ECM reaction, and TGF-β signaling pathways. As expected, transfection of Col1a1-miR-29b or CMV-miR-29b vector partially reversed the activation of these pathways. We also analyzed the expression pattern of the top 100 miR-29b targeting genes in these cells using the RNA-sequencing data. We identified that miR-29b targeted a broad spectrum of ECM genes, but the inhibition effect is mostly moderate. In summary, our work demonstrated that the Col1a1-miR-29b vector can be used as a dynamic regulator of collagen and other ECM protein expression in response to fibrotic stimulation, which could potentially reduce unnecessary side effect due to excessive miR-29b levels while remaining an effective potential therapeutic approach for fibrosis.
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Affiliation(s)
- Xiaoming Fan
- Department of Medicine, University of Toledo, Toledo, Ohio, United States of America
| | - Yingnyu Gao
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States of America
| | - Xiaolu Zhang
- Department of Medicine, University of Toledo, Toledo, Ohio, United States of America
| | - Haroon Y. Lughmani
- Department of Medicine, University of Toledo, Toledo, Ohio, United States of America
| | - David J. Kennedy
- Department of Medicine, University of Toledo, Toledo, Ohio, United States of America
| | - Steven T. Haller
- Department of Medicine, University of Toledo, Toledo, Ohio, United States of America
| | - Sandrine V. Pierre
- Marshall Institute for Interdisciplinary Research, Marshall University, Huntington, West Virginia, United States of America
| | - Joseph I. Shapiro
- Joan C. Edwards School of Medicine, Department of Biomedical Sciences, Marshall University, Huntington, West Virginia, United States of America
| | - Jiang Tian
- Joan C. Edwards School of Medicine, Department of Biomedical Sciences, Marshall University, Huntington, West Virginia, United States of America
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6
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Lyu X, Hu M, Peng J, Zhang X, Sanders YY. HDAC inhibitors as antifibrotic drugs in cardiac and pulmonary fibrosis. Ther Adv Chronic Dis 2019; 10:2040622319862697. [PMID: 31367296 PMCID: PMC6643173 DOI: 10.1177/2040622319862697] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 06/17/2019] [Indexed: 12/14/2022] Open
Abstract
Fibrosis usually results from dysregulated wound repair and is characterized by
excessive scar tissue. It is a complex process with unclear mechanisms.
Accumulating evidence indicates that epigenetic alterations, including histone
acetylation, play a pivotal role in this process. Histone acetylation is
governed by histone acetyltransferases (HATs) and histone deacetylases (HDACs).
HDACs are enzymes that remove the acetyl groups from both histone and nonhistone
proteins. Aberrant HDAC activities are observed in fibrotic diseases, including
cardiac and pulmonary fibrosis. HDAC inhibitors (HDACIs) are molecules that
block HDAC functions. HDACIs have been studied extensively in a variety of
tumors. Currently, there are four HDACIs approved by the US Food and Drug
Administration for cancer treatment yet none for fibrotic diseases. Emerging
evidence from in vitro and in vivo preclinical
studies has presented beneficial effects of HDACIs in preventing or reversing
fibrogenesis. In this review, we summarize the latest findings of the roles of
HDACs in the pathogenesis of cardiac and pulmonary fibrosis and highlight the
potential applications of HDACIs in these two fibrotic diseases.
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Affiliation(s)
- Xing Lyu
- Laboratory of Clinical Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Min Hu
- Laboratory of Clinical Medicine, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jieting Peng
- Department of Geriatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiangyu Zhang
- Department of Geriatrics, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Yan Y Sanders
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham, 901 19 Street South, BMRII Room 408, Birmingham, AL 35294, USA
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7
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Khalaf FK, Dube P, Mohamed A, Tian J, Malhotra D, Haller ST, Kennedy DJ. Cardiotonic Steroids and the Sodium Trade Balance: New Insights into Trade-Off Mechanisms Mediated by the Na⁺/K⁺-ATPase. Int J Mol Sci 2018; 19:E2576. [PMID: 30200235 PMCID: PMC6165267 DOI: 10.3390/ijms19092576] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 08/24/2018] [Accepted: 08/26/2018] [Indexed: 02/06/2023] Open
Abstract
In 1972 Neal Bricker presented the "trade-off" hypothesis in which he detailed the role of physiological adaptation processes in mediating some of the pathophysiology associated with declines in renal function. In the late 1990's Xie and Askari published seminal studies indicating that the Na⁺/K⁺-ATPase (NKA) was not only an ion pump, but also a signal transducer that interacts with several signaling partners. Since this discovery, numerous studies from multiple laboratories have shown that the NKA is a central player in mediating some of these long-term "trade-offs" of the physiological adaptation processes which Bricker originally proposed in the 1970's. In fact, NKA ligands such as cardiotonic steroids (CTS), have been shown to signal through NKA, and consequently been implicated in mediating both adaptive and maladaptive responses to volume overload such as fibrosis and oxidative stress. In this review we will emphasize the role the NKA plays in this "trade-off" with respect to CTS signaling and its implication in inflammation and fibrosis in target organs including the heart, kidney, and vasculature. As inflammation and fibrosis exhibit key roles in the pathogenesis of a number of clinical disorders such as chronic kidney disease, heart failure, atherosclerosis, obesity, preeclampsia, and aging, this review will also highlight the role of newly discovered NKA signaling partners in mediating some of these conditions.
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Affiliation(s)
- Fatimah K Khalaf
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Health Education Building RM 205, 3000 Arlington Ave, Toledo, OH 43614, USA.
| | - Prabhatchandra Dube
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Health Education Building RM 205, 3000 Arlington Ave, Toledo, OH 43614, USA.
| | - Amal Mohamed
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Health Education Building RM 205, 3000 Arlington Ave, Toledo, OH 43614, USA.
| | - Jiang Tian
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Health Education Building RM 205, 3000 Arlington Ave, Toledo, OH 43614, USA.
| | - Deepak Malhotra
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Health Education Building RM 205, 3000 Arlington Ave, Toledo, OH 43614, USA.
| | - Steven T Haller
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Health Education Building RM 205, 3000 Arlington Ave, Toledo, OH 43614, USA.
| | - David J Kennedy
- Department of Medicine, University of Toledo College of Medicine and Life Sciences, Health Education Building RM 205, 3000 Arlington Ave, Toledo, OH 43614, USA.
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8
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Modeling of inhomogeneous electromagnetic fields in the nervous system: a novel paradigm in understanding cell interactions, disease etiology and therapy. Sci Rep 2018; 8:12909. [PMID: 30150694 PMCID: PMC6110729 DOI: 10.1038/s41598-018-31054-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 08/10/2018] [Indexed: 12/23/2022] Open
Abstract
All major processes in the nervous system depend on interactions between cells and nerve fibers. In this work we present a novel model of inhomogeneous electromagnetic fields originating from nerve fibers and delineate their influence on cells. By expanding Hodgkin-Huxley's applied current into axial current, governed by[Formula: see text], we reveal that cell-with-neuron interactions are regulated by the strength of the electromagnetic fields, which are homogeneous up to 2.066 μm or 6.606 μm away from neurilemma and axolemma, respectively. At the nodes of Ranvier, these fields reach strengths of 3.0 × 10-12T, while at the myelinated segments they only peak at 2.3 × 10-12T. These are the same fields which are, due to inhomogeneity, detected as 1,000 times weaker by magnetoencephalography. Considering the widespread occurrence of neurodegenerative disorders, our model reveals that a 50% demyelination increases the field strength by 0.35 × 10-12T, while a complete demyelination increases it by 0.7 × 10-12T. Since this suggests that the inhomogeneous electromagnetic fields around neurons play a role in physiological and pathological processes, including cell-to-neuron and cell-to-cell communication, their improved understanding opens up new therapeutic strategies based on electromagnetic field modulation or cell's surface charge alteration.
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