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Sano HI, Toki T, Naito Y, Tomita M. Developmental changes in the balance of glycolytic ATP production and oxidative phosphorylation in ventricular cells: A simulation study. J Theor Biol 2017; 419:269-277. [PMID: 28237394 DOI: 10.1016/j.jtbi.2017.02.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 11/19/2022]
Abstract
The developmental program of the heart requires accurate regulation to ensure continuous circulation and simultaneous cardiac morphogenesis, because any functional abnormalities may progress to congenital heart malformation. Notably, energy metabolism in fetal ventricular cells is regulated in a manner that differs from adult ventricular cells: fetal cardiomyocytes generally have immature mitochondria and fetal ventricular cells show greater dependence on glycolytic ATP production. However, although various characteristics of energy metabolism in fetal ventricular cells have been reported, to our knowledge, a quantitative description of the contributions of these factors to fetal ventricular cell functions has not yet been established. Here, we constructed a mathematical model to integrate various characteristics of fetal ventricular cells and predicted the contribution of each characteristic to the maintenance of intracellular ATP concentration and sarcomere contraction under anoxic conditions. Our simulation results demonstrated that higher glycogen content, higher hexokinase activity, and lower creatine concentration helped prolong the time for which ventricular cell contraction was maintained under anoxic conditions. The integrated model also enabled us to quantitatively assess the contributions of factors related to energy metabolism in ventricular cells. Because fetal cardiomyocytes exhibit similar energy metabolic profiles to stem cell-derived cardiomyocytes and those in the failing heart, an improved understanding of these fetal ventricular cells will contribute to a better comprehension of the processes in stem cell-derived cardiomyocytes or under pathological conditions.
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Affiliation(s)
- Hitomi I Sano
- Institute for Advanced Biosciences, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan; Department of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan.
| | - Tamami Toki
- Institute for Advanced Biosciences, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan; Systems Biology Program, Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan.
| | - Yasuhiro Naito
- Institute for Advanced Biosciences, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan; Systems Biology Program, Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan; Department of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan.
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan; Systems Biology Program, Graduate School of Media and Governance, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan; Department of Environment and Information Studies, Keio University, 5322 Endo, Fujisawa, Kanagawa 252-0882, Japan.
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2
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Pratico ED, Feger BJ, Watson MJ, Sullenger BA, Bowles DE, Milano CA, Nair SK. RNA-Mediated Reprogramming of Primary Adult Human Dermal Fibroblasts into c-kit(+) Cardiac Progenitor Cells. Stem Cells Dev 2015; 24:2622-33. [PMID: 26176491 DOI: 10.1089/scd.2015.0073] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Cardiovascular disease is the leading cause of death in the United States. Heart failure is a common, costly, and potentially fatal condition that is inadequately managed by pharmaceuticals. Cardiac repair therapies are promising alternative options. A potential cardiac repair therapy involves reprogramming human fibroblasts toward an induced cardiac progenitor-like state. We developed a clinically useful and safer reprogramming method by nonintegrative delivery of a cocktail of cardiac transcription factor-encoding mRNAs into autologous human dermal fibroblasts obtained from skin biopsies. Using this method, adult and neonatal dermal fibroblasts were reprogrammed into cardiac progenitor cells (CPCs) that expressed c-kit, Isl-1, and Nkx2.5. Furthermore, these reprogrammed CPCs differentiated into cardiomyocytes (CMs) in vitro as judged by increased expression of cardiac troponin T, α-sarcomeric actinin, RyR2, and SERCA2 and displayed enhanced caffeine-sensitive calcium release. The ability to reprogram patient-derived dermal fibroblasts into c-kit(+) CPCs and differentiate them into functional CMs provides clinicians with a potential new source of CPCs for cardiac repair from a renewable source and an alternative therapy in the treatment of heart failure.
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Affiliation(s)
- Elizabeth D Pratico
- Department of Surgery, Duke University Medical Center , Durham, North Carolina
| | - Bryan J Feger
- Department of Surgery, Duke University Medical Center , Durham, North Carolina
| | - Michael J Watson
- Department of Surgery, Duke University Medical Center , Durham, North Carolina
| | - Bruce A Sullenger
- Department of Surgery, Duke University Medical Center , Durham, North Carolina
| | - Dawn E Bowles
- Department of Surgery, Duke University Medical Center , Durham, North Carolina
| | - Carmelo A Milano
- Department of Surgery, Duke University Medical Center , Durham, North Carolina
| | - Smita K Nair
- Department of Surgery, Duke University Medical Center , Durham, North Carolina
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Phosphorylation of Ser283 enhances the stiffness of the tropomyosin head-to-tail overlap domain. Arch Biochem Biophys 2015; 571:10-5. [PMID: 25726728 DOI: 10.1016/j.abb.2015.02.026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 02/19/2015] [Accepted: 02/20/2015] [Indexed: 12/15/2022]
Abstract
The ends of coiled-coil tropomyosin molecules are joined together by nine to ten residue-long head-to-tail "overlapping domains". These short four-chained interconnections ensure formation of continuous tropomyosin cables that wrap around actin filaments. Molecular Dynamics simulations indicate that the curvature and bending flexibility at the overlap is 10-20% greater than over the rest of the molecule, which might affect head-to-tail filament assembly on F-actin. Since the penultimate residue of striated muscle tropomyosin, Ser283, is a natural target of phosphorylating enzymes, we have assessed here if phosphorylation adjusts the mechanical properties of the tropomyosin overlap domain. MD simulations show that phosphorylation straightens the overlap to match the curvature of the remainder of tropomyosin while stiffening it to equal or exceed the rigidity of canonical coiled-coil regions. Corresponding EM data on phosphomimetic tropomyosin S283D corroborate these findings. The phosphorylation-induced change in mechanical properties of tropomyosin likely results from electrostatic interactions between C-terminal phosphoSer283 and N-terminal Lys12 in the four-chain overlap bundle, while promoting stronger interactions among surrounding residues and thus facilitating tropomyosin cable assembly. The stiffening effect of D283-tropomyosin noted correlates with previously observed enhanced actin-tropomyosin activation of myosin S1-ATPase, suggesting a role for the tropomyosin phosphorylation in potentiating muscle contraction.
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Uesugi M, Ojima A, Taniguchi T, Miyamoto N, Sawada K. Low-density plating is sufficient to induce cardiac hypertrophy and electrical remodeling in highly purified human iPS cell-derived cardiomyocytes. J Pharmacol Toxicol Methods 2014; 69:177-88. [DOI: 10.1016/j.vascn.2013.11.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 11/20/2013] [Accepted: 11/20/2013] [Indexed: 11/24/2022]
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Okubo C, Sano HI, Naito Y, Tomita M. Contribution of quantitative changes in individual ionic current systems to the embryonic development of ventricular myocytes: a simulation study. J Physiol Sci 2013; 63:355-67. [PMID: 23760774 PMCID: PMC3751412 DOI: 10.1007/s12576-013-0271-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 05/20/2013] [Indexed: 12/29/2022]
Abstract
Early embryonic rodent ventricular cells exhibit spontaneous action potential (AP), which disappears in later developmental stages. Here, we used 3 mathematical models-the Kyoto, Ten Tusscher-Panfilov, and Luo-Rudy models-to present an overview of the functional landscape of developmental changes in embryonic ventricular cells. We switched the relative current densities of 9 ionic components in the Kyoto model, and 160 of 512 representative combinations were predicted to result in regular spontaneous APs, in which the quantitative changes in Na(+) current (I Na) and funny current (I f) made large contributions to a wide range of basic cycle lengths. In all three models, the increase in inward rectifier current (I K1) before the disappearance of I f was predicted to result in abnormally high intracellular Ca(2+) concentrations. Thus, we demonstrated that the developmental changes in APs were well represented, as I Na increased before the disappearance of I f, followed by a 10-fold increase in I K1.
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Affiliation(s)
- Chikako Okubo
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
| | - Hitomi I. Sano
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
| | - Yasuhiro Naito
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
| | - Masaru Tomita
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa 252-0882 Japan
- Department of Environment and Information Studies, Keio University, Fujisawa, Kanagawa 252-0882 Japan
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Wu Y, Feng W, Zhang H, Li S, Wang D, Pan X, Hu S. Ca²+-regulatory proteins in cardiomyocytes from the right ventricle in children with congenital heart disease. J Transl Med 2012; 10:67. [PMID: 22472319 PMCID: PMC3464735 DOI: 10.1186/1479-5876-10-67] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 04/02/2012] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hypoxia and hypertrophy are the most frequent pathophysiological consequence of congenital heart disease (CHD) which can induce the alteration of Ca2+-regulatory proteins and inhibit cardiac contractility. Few studies have been performed to examine Ca2+-regulatory proteins in human cardiomyocytes from the hypertrophic right ventricle with or without hypoxia. METHODS Right ventricle tissues were collected from children with tetralogy of Fallot [n = 25, hypoxia and hypertrophy group (HH group)], pulmonary stenosis [n = 25, hypertrophy group (H group)], or small isolated ventricular septal defect [n = 25, control group (C group)] during open-heart surgery. Paraffin sections of tissues were stained with 3,3'-dioctadecyloxacarbocyanine perchlorate to measure cardiomyocyte size. Expression levels of Ca2+-regulatory proteins [sarcoplasmic reticulum Ca2+-ATPase (SERCA2a), ryanodine receptor (RyR2), sodiumcalcium exchanger (NCX), sarcolipin (SLN) and phospholamban (PLN)] were analysed by means of real-time PCR, western blot, or immunofluorescence. Additionally, phosphorylation level of RyR and PLN and activity of protein phosphatase (PP1) were evaluated using western blot. RESULTS Mild cardiomyocyte hypertrophy of the right ventricle in H and HH groups was confirmed by comparing cardiomyocyte size. A significant reduction of SERCA2a in mRNA (P<0.01) was observed in the HH group compared with the C group. The level of Ser16-phosphorylated PLN was down-regulated (P<0.01) and PP1 was increased (P<0.01) in the HH group compared to that in the C group. CONCLUSIONS The decreased SERCA2a mRNA may be a biomarker of the pathological process in the early stage of cyanotic CHD with the hypertrophic right ventricle. A combination of hypoxia and hypertrophy can induce the adverse effect of PLN-Ser16 dephosphorylation. Increased PP1 could result in the decreased PLN-Ser16 and inhibition of PP1 is a potential therapeutic target for heart dysfunction in pediatrics.
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Affiliation(s)
- Yihe Wu
- State Key Laboratory of Cardiovascular Medicine, Cardiovascular Institute & Fuwai Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
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Itoh H, Naito Y, Tomita M. Simulation of developmental changes in action potentials with ventricular cell models. SYSTEMS AND SYNTHETIC BIOLOGY 2011; 1:11-23. [PMID: 19003434 PMCID: PMC2533146 DOI: 10.1007/s11693-006-9002-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
During cardiomyocyte development, early embryonic ventricular cells show spontaneous activity that disappears at a later stage. Dramatic changes in action potential are mediated by developmental changes in individual ionic currents. Hence, reconstruction of the individual ionic currents into an integrated mathematical model would lead to a better understanding of cardiomyocyte development. To simulate the action potential of the rodent ventricular cell at three representative developmental stages, quantitative changes in the ionic currents, pumps, exchangers, and sarcoplasmic reticulum (SR) Ca(2+) kinetics were represented as relative activities, which were multiplied by conductance or conversion factors for individual ionic systems. The simulated action potential of the early embryonic ventricular cell model exhibited spontaneous activity, which ceased in the simulated action potential of the late embryonic and neonatal ventricular cell models. The simulations with our models were able to reproduce action potentials that were consistent with the reported characteristics of the cells in vitro. The action potential of rodent ventricular cells at different developmental stages can be reproduced with common sets of mathematical equations by multiplying conductance or conversion factors for ionic currents, pumps, exchangers, and SR Ca(2+) kinetics by relative activities.
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Affiliation(s)
- Hitomi Itoh
- Institute for Advanced Biosciences, Keio University, Fujisawa, Kanagawa, 252-8520, Japan,
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Kawamura Y, Ishiwata T, Takizawa M, Ishida H, Asano Y, Nonoyama S. Fetal and neonatal development of Ca2+ transients and functional sarcoplasmic reticulum in beating mouse hearts. Circ J 2010; 74:1442-50. [PMID: 20526040 DOI: 10.1253/circj.cj-09-0793] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND It is generally accepted that Ca(2+)-induced Ca(2+) release is not the predominant mechanism during embryonic stages. Most studies have been conducted either on primary cultures or acutely isolated cells, in which an apparent reduction of ryanodine receptor density and alterations in the cell shape have been reported. The aim of the present study was to investigate developmental changes in Ca(2+) transients using whole hearts of mouse embryos and neonates. METHODS AND RESULTS Fluo-3 fluorescence signals from stimulated whole hearts were detected using a photomultiplier and stored as Ca(2+) transients. The upstroke and decay of Ca(2+) transients became more rapid from the late embryonic stages to the neonatal stage. After thapsigargin application (an inhibitor of the sarcoplasmic Ca(2+)-ATPase [SERCA]), time to 50% relaxation (T(50)) of Ca(2+) transients was significantly prolonged. There were no significant changes in T(50) after Ru360 application (an inhibitor of mitochondrial Ca(2+) uniporter). The rate of increase in the amplitude of Ca(2+) transients after caffeine application became larger during developmental stages. CONCLUSIONS Ca(2+) homeostasis developmentally changes from a slow rise and decay of Ca(2+) transients to rapid kinetics after the mid-embryonic stage. SERCA began to contribute significantly to Ca(2+) homeostasis at early embryonic stages and sarcoplasmic reticulum Ca(2+) contents increased from embryonic to neonatal stages, whereas mitochondrial Ca(2+) uptake did not contribute to Ca(2+) transients on a beat-to-beat basis.
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Affiliation(s)
- Yoichi Kawamura
- Department of Pediatrics, National Defense Medical College, Tokorozawa, Japan
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Wiegerinck RF, Cojoc A, Zeidenweber CM, Ding G, Shen M, Joyner RW, Fernandez JD, Kanter KR, Kirshbom PM, Kogon BE, Wagner MB. Force frequency relationship of the human ventricle increases during early postnatal development. Pediatr Res 2009; 65:414-9. [PMID: 19127223 PMCID: PMC2788428 DOI: 10.1203/pdr.0b013e318199093c] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Understanding developmental changes in contractility is critical to improving therapies for young cardiac patients. Isometric developed force was measured in human ventricular muscle strips from two age groups: newborns (<2 wk) and infants (3-14 mo) undergoing repair for congenital heart defects. Muscle strips were paced at several cycle lengths (CLs) to determine the force frequency response (FFR). Changes in Na/Ca exchanger (NCX), sarcoplasmic reticulum Ca-ATPase (SERCA), and phospholamban (PLB) were characterized. At CL 2000 ms, developed force was similar in the two groups. Decreasing CL increased developed force in the infant group to 131 +/- 8% (CL 1000 ms) and 157 +/- 18% (CL 500 ms) demonstrating a positive FFR. The FFR in the newborn group was flat. NCX mRNA and protein levels were significantly larger in the newborn than infant group whereas SERCA levels were unchanged. PLB mRNA levels and PLB/SERCA ratio increased with age. Immunostaining for NCX in isolated newborn cells showed peripheral staining. In infant cells, NCX was also found in T-tubules. SERCA staining was regular and striated in both groups. This study shows for the first time that the newborn human ventricle has a flat FFR, which increases with age and may be caused by developmental changes in calcium handling.
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Affiliation(s)
- Rob F Wiegerinck
- Department of Pediatrics, Emory University, Atlanta, Georgia 30322, USA
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Baptista MJ, Recamán M, Melo-Rocha G, Nogueira-Silva C, Roriz JM, Soares-Fernandes J, Gonzaga S, Santos M, Leite-Moreira A, Areias JC, Correia-Pinto J. Myocardium expression of connexin 43, SERCA2a, and myosin heavy chain isoforms are preserved in nitrofen-induced congenital diaphragmatic hernia rat model. J Pediatr Surg 2006; 41:1532-8. [PMID: 16952587 DOI: 10.1016/j.jpedsurg.2006.05.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Previous morphological studies had produced controversial results with regard to heart development in congenital diaphragmatic hernia (CDH), whereas a few publications investigated cardiac function and myocardial maturation. Myocardium maturation is associated with age-dependent increasing of gene expression of gap junction protein connexin 43 (Cx43), adenosine triphosphatase of the sarcoplasmic reticulum (SERCA2a), as well as switching of myosin heavy chains (MHCs) from beta to alpha isoforms. Our aim was to evaluate myocardium maturity in nitrofen-induced CDH rat model. METHODS Fetuses from dated pregnant Sprague-Dawley rats were assigned to 3 experimental groups: control, nitrofen (exposed to nitrofen, without CDH), and CDH (exposed to nitrofen, with CDH). Myocardial samples collected from left ventricle free wall were processed to (i) quantification of messenger RNA (mRNA) of Cx43, SERCA2a, alpha and beta MHC isoforms, as well as beta-actin (housekeeping gene); and (ii) separation of MHC isoforms (alpha and beta isoforms) by sodium dodecyl sulfate polyacrylamide gel electrophoresis silver stained. RESULTS We demonstrated that there is no difference in myocardial gene expression of Cx43 (control, 1.0 +/- 0.1; nitrofen, 1.1 +/- 0.2; CDH, 1.3 +/- 0.2) and SERCA2a (control, 1.0 +/- 0.1; nitrofen, 0.9 +/- 0.1; CDH, 1.0 +/- 0.2). Myocardial gene expressions of alpha and beta mRNA of MHC isoforms were slightly decreased both in nitrofen and CDH fetuses when compared with control fetuses, but evaluation of the alpha-to-beta ratios of MHC isoforms at protein level revealed no significant differences between CDH and control (control, 16.9 +/- 2.5; CDH, 17.0 +/- 2.0). CONCLUSIONS Myocardial quantification of Cx43 and SERCA2a mRNA, as well as the expression pattern of MHC isoforms at protein levels, was similar in all studied groups. We predict, therefore, that acute heart failure commonly observed in CDH infants might be attributed predominantly to cardiac overload secondary to severe pulmonary hypertension rather than to myocardial immaturity.
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Affiliation(s)
- Maria João Baptista
- Life and Health Sciences, Research Institute (ICVS), School of Health Sciences, University of Minho, 4709-057 Braga, Portugal
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Huang J, Hove-Madsen L, Tibbits GF. Na+/Ca2+ exchange activity in neonatal rabbit ventricular myocytes. Am J Physiol Cell Physiol 2004; 288:C195-203. [PMID: 15317663 DOI: 10.1152/ajpcell.00183.2004] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Much less is known about the contributions of the Na(+)/Ca(2+) exchanger (NCX) and sarcoplasmic reticulum (SR) Ca(2+) pump to cell relaxation in neonatal compared with adult mammalian ventricular myocytes. Based on both biochemical and molecular studies, there is evidence of a much higher density of NCX at birth that subsequently decreases during the next 2 wk of development. It has been hypothesized, therefore, that NCX plays a relatively more important role for cytosolic Ca(2+) decline in neonates as well as, perhaps, a role in excitation-contraction coupling in reverse mode. We isolated neonatal ventricular myocytes from rabbits in four different age groups: 3, 6, 10, and 20 days of age. Using an amphotericin-perforated patch-clamp technique in fluo-3-loaded myocytes, we measured the caffeine-induced inward NCX current (I(NCX)) and the Ca(2+) transient. We found that the integral of I(NCX), an indicator of SR Ca(2+) content, was greatest in myocytes from younger age groups when normalized by cell surface area and that it decreased with age. The velocity of Ca(2+) extrusion by NCX (V(NCX)) was linear with [Ca(2+)] and did not indicate saturation kinetics until [Ca(2+)] reached 1-3 microM for each age group. There was a significantly greater time delay between the peaks of I(NCX) and the Ca(2+) transient in myocytes from the youngest age groups. This observation could be related to structural differences in the subsarcolemmal microdomains as a function of age.
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Affiliation(s)
- Jingbo Huang
- Cardiac Membrane Research Laboratory, Simon Fraser University, Burnaby, British Columbia, Canada
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Chen F, Shannon K, Ding S, Silva ME, Wetzel GT, Klitzner TS, Krogstad P. HIV type 1 glycoprotein 120 inhibits cardiac myocyte contraction. AIDS Res Hum Retroviruses 2002; 18:777-84. [PMID: 12167269 DOI: 10.1089/08892220260139512] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Cardiomyopathy is a common, life-threatening, but poorly understood complication of HIV infection. The purpose of the present study is to study the effects of an HIV surface envelope protein, glycoprotein 120 (gp120), on cell contraction and L-type Ca(2+) current in rabbit ventricular myocytes. Rabbit ventricular cells were isolated by an enzyme dissociation method. Cell contractions were induced by electric field stimulation. Whole cell L-type Ca(2+) channel currents were measured by the whole cell voltage-clamp technique. We found that perfusion with solution containing gp120 (0.1 microg/ml) derived from HIV-1(SF2) significantly inhibited field-stimulated contractions and L-type Ca(2+) current in rabbit ventricular myocytes as compared with perfusion with buffer alone. These results suggest that HIV-1 gp120 may directly contribute to cardiac dysfunction as seen in many HIV patients.
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Affiliation(s)
- Fuhua Chen
- UCLA School of Medicine, 675 C.E. Young Drive South, MRL 3754, Los Angeles, CA 90095-7045, USA.
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Bassani RA, Bassani JWM. Contribution of Ca(2+) transporters to relaxation in intact ventricular myocytes from developing rats. Am J Physiol Heart Circ Physiol 2002; 282:H2406-13. [PMID: 12003852 DOI: 10.1152/ajpheart.00320.2001] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The relative contributions of Ca(2+) transporters to intracellular Ca(2+) concentration ([Ca(2+)](i)) decline associated with twitch relaxation were analyzed in intact ventricular myocytes from developing and adult rats. This was accomplished by estimation of individual integrated Ca(2+) fluxes with the use of kinetic parameters calculated from [Ca(2+)](i) measurements during twitches and caffeine-evoked contractures, and from myocardial passive Ca(2+) buffering data. Our main findings were the following: 1) twitch relaxation and [Ca(2+)](i) decline were significantly slower during the first postnatal week than in adults, 2) inhibition of sarcoplasmic reticulum (SR) Ca(2+) accumulation resulted in faster [Ca(2+)](i) decline in young cells than in adult cells, 3) the contributions of the SR Ca(2+) uptake and Na(+)/Ca(2+) exchange (NCX) to twitch relaxation increased from ~75 to 92%, and decreased from 24 to 5%, respectively, from birth to adulthood, and 4) Ca(2+) transport by the sarcolemmal Ca(2+)-ATPase was apparently increased in neonates. Our data indicate that despite a marked increase in NCX contribution to cell relaxation in immature rats, the SR Ca(2+)-ATPase appears to be the predominant transporter responsible for relaxation-associated [Ca(2+)](i) decline from birth to adulthood.
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Affiliation(s)
- Rosana A Bassani
- Centro de Engenharia Biomédica and Departamento de Engenharia Biomédica/ Faculdade de Engenharia Elétrica e de Computação, Universidade Estadual de Campinas, Campinas 13083-971, Brazil.
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14
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Affiliation(s)
- P D Booker
- Paediatric Anaesthesia, University of Liverpool, Alder Hey Children's Hospital, Liverpool, UK.
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15
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Abstract
In this study we report, for the first time, on the gene expression of human cardiac SERCA2a, L-type (alpha(1C)) and T-type (alpha(1H)) Ca channels during development, using RNase protection assay, relative quantitative RT-PCR and Western blot. Human hearts during early gestation (8- to 20-wk gestation), neonatal (1- to 4-d-old) and adult (18- to 48-year-old) stages were used. The results show that T-type Ca channel alpha(1H) subunit mRNA decreased and that L-type Ca channel alpha(1C) subunit mRNA increased with development. While the levels of sarcoplasmic reticulum ATPase (SERCA2a) mRNA did not significantly change with development, its protein levels increased with development. In conclusion, SERCA2a, L-type and T-type Ca channel transcripts were detected as early as 8-wk gestation. Defining the profile of Ca handling proteins during development is important to the understanding of excitation-contraction (EC)-coupling of the developing human heart.
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MESH Headings
- Adult
- Base Sequence
- Blotting, Western
- Calcium Channels, L-Type/genetics
- Calcium Channels, T-Type/genetics
- Calcium-Transporting ATPases/genetics
- DNA Primers
- Heart/embryology
- Humans
- Infant, Newborn
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA, Ribosomal, 18S/genetics
- RNA, Ribosomal, 18S/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sarcoplasmic Reticulum Calcium-Transporting ATPases
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Affiliation(s)
- Y Qu
- Molecular and Cellular Cardiology Program, VA New York Harbor Healthcare System and SUNY Health Science Centers at Brooklyn, NY 11209, USA
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Periasamy M, Huke S. SERCA pump level is a critical determinant of Ca(2+)homeostasis and cardiac contractility. J Mol Cell Cardiol 2001; 33:1053-63. [PMID: 11444913 DOI: 10.1006/jmcc.2001.1366] [Citation(s) in RCA: 193] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The control of intracellular calcium is central to regulation of cardiac contractility. A defect in SR Ca(2+)transport and SR Ca(2+)ATPase pump activity and expression level has been implicated as a major player in cardiac dysfunction. However, a precise cause-effect relationship between alterations in SERCA pump level and cardiac contractility could not be established from these studies. Progress in transgenic mouse technology and adenoviral gene transfer has provided new tools to investigate the role of SERCA pump level in the heart. This review focuses on how alterations in SERCA level affect Ca(2+)homeostasis and cardiac contractility. It discusses the consequences of altered SERCA pump levels for the expression and activity of other Ca(2+)handling proteins. Furthermore, the use of SERCA pump as a therapeutic target for gene therapy of heart failure is evaluated.
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Affiliation(s)
- M Periasamy
- Division of Cardiology, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, Ohio 45267-0542, USA.
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