scholarly journals FGF-16 is released from neonatal cardiac myocytes and alters growth-related signaling: a possible role in postnatal development

2008 ◽  
Vol 294 (5) ◽  
pp. C1242-C1249 ◽  
Author(s):  
Shun Yan Lu ◽  
David P. Sontag ◽  
Karen A. Detillieux ◽  
Peter A. Cattini
Keyword(s):  
Cell Cycle ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Gene Array ◽  
Neonatal Rat ◽  
Proliferative Potential ◽  
Mrna Accumulation ◽  
Fgf Receptor ◽  
Adult Rat ◽  
Pkc Activation

FGF-16 has been reported to be preferentially expressed in the adult rat heart. We have investigated the expression of FGF-16 in the perinatal and postnatal heart and its functional significance in neonatal rat cardiac myocytes. FGF-16 mRNA accumulation was observed by quantitative RT-PCR between neonatal days 1 and 7, with this increased expression persisting into adulthood. FGF-2 has been shown to increase neonatal rat cardiac myocyte proliferative potential via PKC activation. Gene array analysis revealed that FGF-16 inhibited the upregulation by FGF-2 of cell cycle promoting genes including cyclin F and Ki67. Furthermore, the CDK4/6 inhibitor gene Arf/INK4A was upregulated with the combination of FGF-16 and FGF-2 but not with either factor on its own. The effect on Ki67 was validated by protein immunodetection, which also showed that FGF-16 significantly decreased FGF-2-induced Ki67 labeling of cardiac myocytes, although it alone had no effect on Ki67 labeling. Inhibition of p38 MAPK potentiated cardiac myocyte proliferation induced by FGF-2 but did not alter the inhibitory action of FGF-16. Receptor binding assay showed that FGF-16 can compete with FGF-2 for binding sites including FGF receptor 1. FGF-16 had no effect on activated p38, ERK1/2, or JNK/SAPK after FGF-2 treatment. However, FGF-16 inhibited PKC-α and PKC-ε activation induced by FGF-2 and, importantly, IGF-1. Collectively, these data suggest that expression and release of FGF-16 in the neonatal myocardium interfere with cardiac myocyte proliferative potential by altering the local signaling environment via modulation of PKC activation and cell cycle-related gene expression.

Myocyte enlargement, differentiation, and proliferation kinetics in the fetal sheep heart

2007 ◽  
Vol 102 (3) ◽  
pp. 1130-1142 ◽  
Author(s):  
Sonnet S. Jonker ◽  
Lubo Zhang ◽  
Samantha Louey ◽  
George D. Giraud ◽  
Kent L. Thornburg ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Terminal Differentiation ◽  
Normal Growth ◽  
Mass Gain ◽  
Perinatal Period ◽  
Cross Sectional ◽  
Fetal Sheep ◽  
Cardiac Growth

The generation of new myocytes is an essential process of in utero heart growth. Most, or all, cardiac myocytes lose their capacity for proliferation during the perinatal period through the process of terminal differentiation. An increasing number of studies focus on how experimental interventions affect cardiac myocyte growth in the fetal sheep. Nevertheless, fundamental questions about normal growth of the fetal heart remain unanswered. In this study, we determined that during the last third of gestation the hearts of fetal sheep grew primarily by four processes. 1) Myocyte proliferation contributed substantially to daily cardiac mass gain, and the number of cardiac myocytes continued to increase to term. 2) The (hitherto unrecognized) contribution to cardiac growth by the increase in myocyte size associated with the transition from mononucleation to binucleation (terminal differentiation) became considerable from ∼115 days of gestational age (dGA) until term (145dGA). Because binucleation became the more frequent outcome of myocyte cell cycle activity after ∼115dGA, the number of binucleated myocytes increased at the expense of the number of mononucleated myocytes. Both the interval between nuclear divisions and the duration of cell cycle activity in myocytes decreased substantially during this same period. Finally, cardiac growth was in part due to enlargement of 3) mononucleated and 4) binucleated myocytes, which grew in cross-sectional diameter but not length during the last third of gestation. These data on normal cardiac growth may enable a more detailed understanding of the consequences of experimental and pathological interventions in prenatal life.

Selective turnover of sarcolemmal phospholipids with lethal cardiac myocyte injury

1990 ◽  
Vol 259 (2) ◽  
pp. C325-C331 ◽  
Author(s):  
Y. Miyazaki ◽  
R. W. Gross ◽  
B. E. Sobel ◽  
J. E. Saffitz
Keyword(s):  
Arachidonic Acid ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Cell Injury ◽  
Specific Radioactivity ◽  
Ischemic Injury ◽  
Phospholipid Metabolism ◽  
Neonatal Rat ◽  
Electron Microscopic ◽  
Electron Microscopic Autoradiography

To delineate the biochemical mechanisms responsible for the transition from reversible to irreversible ischemic injury, we used quantitative electron microscopic autoradiography. Specific alterations of phospholipid catabolism in individual subcellular organelles of cardiac myocytes associated with simulated ischemic injury were identified. Neonatal rat cardiac myocytes were incubated with 5 nM [3H]arachidonic acid to label loci of phospholipid turnover and were exposed to 30 microM iodoacetate to produce reversible and irreversible injury. Although only minute amounts of arachidonic acid were incorporated into sarcolemmal phospholipids under control conditions, 20- and 96-fold increases were observed under conditions leading to reversible and irreversible cell injury, respectively. Increases of 5- and 28-fold in the specific radioactivity of sarcolemmal phospholipids in reversibly and irreversibly injured cells occurred in the absence of significant alterations in the specific radioactivity of other subcellular compartments, demonstrating that accelerated phospholipid catabolism was confined essentially to the sarcolemma. Selective catabolism of sarcolemmal phospholipids, known to be highly enriched in arachidonic acid, is likely to augment local accumulation of arachidonic acid, identified recently as a second messenger regulating myocardial K+ channels. Because the biochemical integrity of the sarcolemma is critical to both electrophysiological function and viability of myocytes, the observed selective alterations of sarcolemmal phospholipid metabolism appear to be pivotal determinants of lethal myocardial injury.

Modulation of transmembrane potential of isolated cardiac myocytes by insulin and isoproterenol

1990 ◽  
Vol 259 (2) ◽  
pp. H554-H559
Author(s):  
J. Eckel ◽  
H. Reinauer
Keyword(s):  
Cardiac Myocytes ◽  
Insulin Action ◽  
Transmembrane Potential ◽  
Cardiac Myocyte ◽  
Potassium Conductance ◽  
Diabetic Rats ◽  
Maximal Effect ◽  
Physiological Concentration ◽  
Adult Rat ◽  
Hormonal Modulation

Isolated muscle cells from adult rat heart have been used to study the effects of insulin and catecholamines on transmembrane potential by following triphenylmethylphosphonium cation uptake. Insulin was found to hyperpolarize the cells with a maximal effect of 3.2 +/- 0.7 mV (n = 4) at an insulin concentration of 3 x 10(-9) mol/l. This insulin action was fully antagonized by isoproterenol (10(-5) mol/l), which depolarized the cardiocytes in a dose-dependent fashion with a maximal effect of 9.5 +/- 2.2 mV. Treatment of cardiocytes with ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid or CsCl resulted in a total loss of insulin action, whereas isoproterenol action was not affected. Cardiac myocytes from streptozotocin diabetic rats exhibited an unaltered hyperpolarization by insulin within the physiological concentration range. Isoproterenol now induced a biphasic response with a significant hyperpolarization at low doses and a decreased depolarization at maximal concentrations. In conclusion, 1) hormonal modulation of cardiac myocyte membrane potentials involves hyperpolarization by insulin and depolarization by beta-agonists, 2) insulin action appears to be related to an increased potassium conductance and may be antagonized by beta-stimulation, and 3) membrane potential modulation may be profoundly altered in the diabetic state.

scholarly journals Cardiac Myocyte Cell Cycle Control in Development, Disease, and Regeneration

2007 ◽  
Vol 87 (2) ◽  
pp. 521-544 ◽  
Author(s):  
Preeti Ahuja ◽  
Patima Sdek ◽  
W. Robb MacLellan
Keyword(s):  
Cell Cycle ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Cell Cycle Control ◽  
Cardiac Regeneration ◽  
Perinatal Period ◽  
Fetal Life ◽  
Cell Cycle Reentry ◽  
Adult Cardiac Myocytes ◽  
Species Specific

Cardiac myocytes rapidly proliferate during fetal life but exit the cell cycle soon after birth in mammals. Although the extent to which adult cardiac myocytes are capable of cell cycle reentry is controversial and species-specific differences may exist, it appears that for the vast majority of adult cardiac myocytes the predominant form of growth postnatally is an increase in cell size (hypertrophy) not number. Unfortunately, this limits the ability of the heart to restore function after any significant injury. Interest in novel regenerative therapies has led to the accumulation of much information on the mechanisms that regulate the rapid proliferation of cardiac myocytes in utero, their cell cycle exit in the perinatal period, and the permanent arrest (terminal differentiation) in adult myocytes. The recent identification of cardiac progenitor cells capable of giving rise to cardiac myocyte-like cells has challenged the dogma that the heart is a terminally differentiated organ and opened new prospects for cardiac regeneration. In this review, we summarize the current understanding of cardiomyocyte cell cycle control in normal development and disease. In addition, we also discuss the potential usefulness of cardiomyocyte self-renewal as well as feasibility of therapeutic manipulation of the cardiac myocyte cell cycle for cardiac regeneration.

scholarly journals Proteomic mapping of proteins released during necrosis and apoptosis from cultured neonatal cardiac myocytes

2014 ◽  
Vol 306 (7) ◽  
pp. C639-C647 ◽  
Author(s):  
Kurt D. Marshall ◽  
Michelle A. Edwards ◽  
Maike Krenz ◽  
J. Wade Davis ◽  
Christopher P. Baines
Keyword(s):  
Cell Death ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Ischemia Reperfusion Injury ◽  
Apoptotic Cell ◽  
Ischemia Reperfusion ◽  
Cardiac Injury ◽  
High Mobility ◽  
Neonatal Rat ◽  
Protein Markers

Cardiac injury induces myocyte apoptosis and necrosis, resulting in the secretion and/or release of intracellular proteins. Currently, myocardial injury can be detected by analysis of a limited number of biomarkers in blood or coronary artery perfusate. However, the complete proteomic signature of protein release from necrotic cardiac myocytes is unknown. Therefore, we undertook a proteomic-based study of proteins released from cultured neonatal rat cardiac myocytes in response to H2O2 (necrosis) or staurosporine (apoptosis) to identify novel specific markers of cardiac myocyte cell death. Necrosis and apoptosis resulted in the identification of 147 and 79 proteins, respectively. Necrosis resulted in a relative increase in the amount of many proteins including the classical necrotic markers lactate dehydrogenase (LDH), high-mobility group B1 (HMGB1), myoglobin, enolase, and 14-3-3 proteins. Additionally, we identified several novel markers of necrosis including HSP90, α-actinin, and Trim72, many of which were elevated over control levels earlier than classical markers of necrotic injury. In contrast, the majority of identified proteins remained at low levels during apoptotic cell death, resulting in no candidate markers for apoptosis being identified. Blotting for a selection of these proteins confirmed their release during necrosis but not apoptosis. We were able to confirm the presence of classical necrotic markers in the extracellular milieu of necrotic myocytes. We also were able to identify novel markers of necrotic cell death with relatively early release profiles compared with classical protein markers of necrosis. These results have implications for the discovery of novel biomarkers of necrotic myocyte injury, especially in the context of ischemia-reperfusion injury.

A metabolic role for mitochondria in palmitate-induced cardiac myocyte apoptosis

2000 ◽  
Vol 279 (5) ◽  
pp. H2124-H2132 ◽  
Author(s):  
Genevieve C. Sparagna ◽  
Diane L. Hickson-Bick ◽  
L. Maximilian Buja ◽  
Jeanie B. McMillin
Keyword(s):  
Cardiac Myocytes ◽  
Caspase 3 ◽  
Cardiac Myocyte ◽  
Mitochondrial Permeability Transition ◽  
Permeability Transition ◽  
Carnitine Palmitoyltransferase ◽  
Complex Iii ◽  
Neonatal Rat ◽  
Metabolic Role ◽  
Carnitine Palmitoyltransferase I

After cardiac ischemia, long-chain fatty acids, such as palmitate, increase in plasma and heart. Palmitate has previously been shown to cause apoptosis in cardiac myocytes. Cultured neonatal rat cardiac myocytes were studied to assess mitochondrial alterations during apoptosis. Phosphatidylserine translocation and caspase 3-like activity confirmed the apoptotic action of palmitate. Cytosolic cytochrome cwas detected at 8 h and plateaued at 12 h. The mitochondrial membrane potential (ΔΨ) in tetramethylrhodamine ethyl ester-loaded cardiac myocytes decreased significantly in individual mitochondria by 8 h. This loss was heterogeneous, with a few energized mitochondria per myocyte remaining at 24 h. Total ATP levels remained high at 16 h. The ΔΨ loss was delayed by cyclosporin A, a mitochondrial permeability transition inhibitor. Mitochondrial swelling accompanied changes in ΔΨ. Carnitine palmitoyltransferase I activity fell at 16 h; this decline was accompanied by ceramide increases that paralleled decreased complex III activity. We conclude that carnitine palmitoyltransferase I inhibition, ceramide accumulation, and complex III inhibition are downstream events in cardiac apoptosis mediated by palmitate and occur independent of events leading to caspase 3-like activation.

Abstract 402: Selective Protein Secretion Upon Endoplasmic Reticulum Stress Protects Cardiac Myocytes

2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Shirin Doroudgar ◽  
Donna J Thuerauf ◽  
Mirka Stastna ◽  
Mirko Voelkers ◽  
Jennifer E Van Eyk ◽  
...  
Keyword(s):  
Heart Disease ◽  
Er Stress ◽  
Conditioned Medium ◽  
Cardiac Myocytes ◽  
Protein Secretion ◽  
Cardiac Myocyte ◽  
Culture Media ◽  
Neonatal Rat ◽  
Glucose Regulated Protein ◽  
Er Calcium

Protein secretion is important for proper cardiac myocyte function. Many secreted proteins are synthesized and folded in the sarco- endo-plasmic reticulum (SR/ER). A number of diseases, including heart disease, alter the ER in ways that impair ER protein folding, causing ER stress, which can result in cardiac myocyte dysfunction and decreased viability. In studies aimed at assessing the effects of ER stress on cardiac myocyte viability, heart disease-related ER stress was mimicked by treating neonatal rat ventricular myocytes (NRVM) with either tunicamycin (TM) or thapsigargin (TG), which inhibit SR/ER protein glycosylation or decrease SR/ER calcium, respectively. When treated in high culture media volumes, both TM and TG caused cardiac myocyte death; however, in low culture media volumes, while TM still caused death, remarkably, TG was protective, suggesting that potentially protective factors were secreted in response to TG but not TM. To characterize these factors, the identities of proteins in control-, TM-, and TG-conditioned medium from NRVM were determined by proteomic approaches using high performance liquid chromatography and mass spectrometry. Twenty-four different proteins, known to be synthesized in the ER, were identified in control-conditioned medium. The levels of eighteen of these proteins, including extracellular matrix proteins, hormones, and growth factors were decreased in TM- and TG-conditioned medium. However, the levels of three SR/ER-resident, calcium-binding chaperones, glucose regulated protein 78 (GRP78), glucose regulated protein 94 (GRP94), and calreticulin were increased in TG-conditioned medium but not in TM-conditioned medium. Furthermore, we found that ischemia/reperfusion, which decreases SR/ER calcium, upregulated secretion of the proteins selectively secreted in response to TG. Thus, while ER stress mediated by TM or TG decreases the movement of most proteins through the secretory pathway, TG, which mimics the effects of heart disease on SR/ER calcium in cardiac myocytes, selectively enhances the secretion of a subset of proteins, which confer protection. Therefore, proteins once thought to be permanent residents of the SR/ER may have novel, extracellular, protective roles in the diseased heart.

1,25-Dihydroxyvitamin D3 regulation of cardiac myocyte proliferation and hypertrophy

1997 ◽  
Vol 272 (4) ◽  
pp. H1751-H1758 ◽  
Author(s):  
T. D. O'Connell ◽  
J. E. Berry ◽  
A. K. Jarvis ◽  
M. J. Somerman ◽  
R. U. Simpson
Keyword(s):  
Cell Cycle ◽  
Cardiac Myocyte ◽  
S Phase ◽  
Neonatal Rat ◽  
Nuclear Antigen ◽  
Dihydroxyvitamin D3 ◽  
Myocyte Hypertrophy ◽  
Protein Levels ◽  
1,25 Dihydroxyvitamin D3 ◽  
Myocyte Proliferation

We previously demonstrated that 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] inhibits myocyte maturation (T. D. O'Connell, D. A. Giacherio, A. K. Jarvis, and R. U. Simpson. Endocrinology 136: 482-488, 1995). To define further the role of 1,25(OH)2D3 in regulating myocardial development, we examined the effects of 1,25(OH)2D3 on proliferation and growth of primary cultures of ventricular myocytes isolated from neonatal rat hearts. When neonatal myocytes were grown in a serum-supplemented medium, cell number approximately doubled, and treating these myocytes with 1,25(OH)2D3 inhibited their proliferation by 56.56% after 4 days. Flow cytometry revealed that 1,25(OH)2D3 reduced the percentage of cells in the S phase of the cell cycle by 31.39% after 4 days. We show for the first time that proliferating cell nuclear antigen protein levels were specifically reduced by 1,25(OH)2D3. Protooncogene c-myc protein levels were also reduced by this hormone. Interestingly, a phorbol ester had a similar effect on myocyte proliferation. Furthermore, 1,25(OH)2D3 increased myocyte protein levels and increased cell size, suggesting that it induces cardiac myocyte hypertrophy. Our findings indicate that 1,25(OH)2D3 and phorbol esters directly regulate myocyte proliferation and induce myocyte hypertrophy. Finally, the data demonstrate that the mechanism by which 1,25(OH)2D3 regulates myocyte proliferation involves blocking entry into the S phase of the cell cycle.

Cardiac myocyte guanosine transport and metabolism

1987 ◽  
Vol 253 (5) ◽  
pp. C645-C651 ◽  
Author(s):  
T. P. Geisbuhler ◽  
D. A. Johnson ◽  
M. J. Rovetto
Keyword(s):  
Cardiac Myocytes ◽  
Rate Constant ◽  
Cardiac Myocyte ◽  
Maximum Velocity ◽  
Guanine Nucleotides ◽  
Inhibition Constant ◽  
Adult Rat ◽  
Adenosine Transport ◽  
Common Carrier ◽  
Rat Cardiac Myocytes

Guanosine transport and metabolism were examined in adult rat cardiac myocytes. Myocytes transported guanosine via saturable [Km = 18 microM, maximum velocity (Vmax) = 3.61 pmol.mg-1.s-1] and nonsaturable (rate constant = 1.47 X 10(-2] processes. The saturable process was inhibited by nitrobenzyl-thioinosine, inosine [inhibition constant (Ki) = 180 microM], and adenosine (Ki = 112 microM). Extracellular guanosine taken up by myocytes was slowly phosphorylated to guanine nucleotides. The majority of guanosine (98%) existed as free intracellular guanosine after 60 s. Countertransport of nucleosides could not be demonstrated in these cells at physiological concentrations in the presence of up to a 10-fold gradient of nucleoside. These studies indicate that adult rat cardiac myocytes can be used to assess myocardial guanosine transport separate from its metabolism. Comparable inhibition of guanosine and adenosine transport by each other and by inosine support the hypothesis that guanosine and adenosine are transported by a common carrier.

Nitric oxide triggers programmed cell death (apoptosis) of adult rat ventricular myocytes in culture

1999 ◽  
Vol 277 (3) ◽  
pp. H1189-H1199 ◽  
Author(s):  
David J. Pinsky ◽  
Walif Aji ◽  
Matthias Szabolcs ◽  
Eleni S. Athan ◽  
Youping Liu ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Cell Death ◽  
Programmed Cell Death ◽  
Cardiac Myocytes ◽  
Cardiac Myocyte ◽  
Ventricular Myocytes ◽  
No Production ◽  
P53 Expression ◽  
Rat Ventricular Myocytes ◽  
Adult Rat

Excessive nitric oxide (NO) production within the heart is implicated in the pathogenesis of myocyte death, but the mechanism whereby NO kills cardiac myocytes is not known. To determine whether NO may trigger programmed cell death (apoptosis) of adult rat ventricular myocytes in culture, the NO donor S-nitroso- N-acetylpenicillamine (SNAP) was shown to kill purified cardiac myocytes in a dose-dependent fashion. In situ analysis of ventricular myocytes plated on chamber slides using nick-end labeling of DNA demonstrated that SNAP induces cardiac myocyte apoptosis, which was confirmed by the identification of oligonucleosomal DNA fragmentation on agarose gel electrophoresis. Similarly, treatment of cardiac myocytes with cytokines that induce inducible NO synthase was shown to cause an NO-dependent induction of apoptosis. Addition of reduced hemoglobin to scavenge NO liberated by SNAP extinguished both the increase in percentage of apoptotic cells and the appearance of DNA ladders. Treatment with SNAP (but not with N-acetylpenicillamine or SNAP + hemoglobin) not only induced apoptosis but resulted in a marked increase in p53 expression in cardiac myocytes detected by Western blotting and immunohistochemistry. These data indicate that NO has the capacity to kill cardiac myocytes by triggering apoptosis and suggest the involvement of p53 in this process.

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