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Upregulation of Phospholipase C Gene Expression Due to Norepinephrine-Induced Hypertrophic Response. Cells 2022; 11:cells11162488. [PMID: 36010565 PMCID: PMC9406906 DOI: 10.3390/cells11162488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 11/28/2022] Open
Abstract
The activation of phospholipase C (PLC) is thought to have a key role in the cardiomyocyte response to several different hypertrophic agents such as norepinephrine, angiotensin II and endothelin-1. PLC activity results in the generation of diacylglycerol and inositol trisphosphate, which are downstream signal transducers for the expression of fetal genes, increased protein synthesis, and subsequent cardiomyocyte growth. In this article, we describe the signal transduction elements that regulate PLC gene expression. The discussion is focused on the norepinephrine- α1-adrenoceptor signaling pathway and downstream signaling processes that mediate an upregulation of PLC isozyme gene expression. Evidence is also indicated to demonstrate that PLC activities self-regulate the expression of PLC isozymes with the suggestion that PLC activities may be part of a coordinated signaling process for the perpetuation of cardiac hypertrophy. Accordingly, from the information provided, it is plausible that specific PLC isozymes could be targeted for the mitigation of cardiac hypertrophy.
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Zhang J, Simpson PC, Jensen BC. Cardiac α1A-adrenergic receptors: emerging protective roles in cardiovascular diseases. Am J Physiol Heart Circ Physiol 2020; 320:H725-H733. [PMID: 33275531 DOI: 10.1152/ajpheart.00621.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
α1-Adrenergic receptors (ARs) are catecholamine-activated G protein-coupled receptors (GPCRs) that are expressed in mouse and human myocardium and vasculature, and play essential roles in the regulation of cardiovascular physiology. Though α1-ARs are less abundant in the heart than β1-ARs, activation of cardiac α1-ARs results in important biologic processes such as hypertrophy, positive inotropy, ischemic preconditioning, and protection from cell death. Data from the Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) indicate that nonselectively blocking α1-ARs is associated with a twofold increase in adverse cardiac events, including heart failure and angina, suggesting that α1-AR activation might also be cardioprotective in humans. Mounting evidence implicates the α1A-AR subtype in these adaptive effects, including prevention and reversal of heart failure in animal models by α1A agonists. In this review, we summarize recent advances in our understanding of cardiac α1A-ARs.
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Affiliation(s)
- Jiandong Zhang
- McAllister Heart Institute, University of North Carolina, School of Medicine, Chapel Hill, North Carolina
| | - Paul C Simpson
- Department of Medicine and Research Service, San Francisco Veterans Affairs Medical Center and Cardiovascular Research Institute, University of California, San Francisco, California
| | - Brian C Jensen
- McAllister Heart Institute, University of North Carolina, School of Medicine, Chapel Hill, North Carolina
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Singal T, Dhalla NS, Tappia PS. Reciprocal regulation of transcription factors and PLC isozyme gene expression in adult cardiomyocytes. J Cell Mol Med 2009; 14:1824-35. [PMID: 19538471 PMCID: PMC3829042 DOI: 10.1111/j.1582-4934.2009.00812.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
By employing a pharmacological approach, we have shown that phospholipase C (PLC) activity is involved in the regulation of gene expression of transcription factors such as c-Fos and c-Jun in cardiomyocytes in response to norepinephrine (NE). However, there is no information available regarding the identity of specific PLC isozymes involved in the regulation of c-Fos and c-Jun or on the involvement of these transcription factors in PLC isozyme gene expression in adult cardiomyocytes. In this study, transfection of cardiomyocytes with PLC isozyme specific siRNA was found to prevent the NE-mediated increases in the corresponding PLC isozyme gene expression, protein content and activity. Unlike PLC gamma(1) gene, silencing of PLC beta(1), beta(3) and delta(1) genes with si RNA prevented the increases in c-Fos and c-Jun gene expression in response to NE. On the other hand, transfection with c-Jun si RNA suppressed the NE-induced increase in c-Jun as well as PLC beta(1), beta(3) and delta(1) gene expression, but had no effect on PLC gamma(1) gene expression. Although transfection of cardiomyocytes with c-Fos si RNA prevented NE-induced expression of c-Fos, PLC beta(1) and PLC beta(3) genes, it did not affect the increases in PLC delta(1) and PLC gamma(1) gene expression. Silencing of either c-Fos or c-Jun also depressed the NE-mediated increases in PLC beta(1), beta(3) and gamma(1) protein content and activity in an isozyme specific manner. Furthermore, silencing of all PLC isozymes as well as of c-Fos and c-Jun resulted in prevention of the NE-mediated increase in atrial natriuretic factor gene expression. These findings, by employing gene silencing techniques, demonstrate that there occurs a reciprocal regulation of transcription factors and specific PLC isozyme gene expression in cardiomyocytes.
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Affiliation(s)
- Tushi Singal
- Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre & Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada
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Singal T, Dhalla NS, Tappia PS. Regulation of c-Fos and c-Jun gene expression by phospholipase C activity in adult cardiomyocytes. Mol Cell Biochem 2009; 327:229-39. [PMID: 19225867 DOI: 10.1007/s11010-009-0061-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2009] [Accepted: 02/04/2009] [Indexed: 11/28/2022]
Abstract
This study was undertaken to determine whether gene expression for transcriptional factors such as c-Fos and c-Jun is regulated by phospholipase C (PLC) activity. Norepinephrine (NE) increased PLC beta(1), beta(3), gamma(1), and delta(1) isozyme gene expression, protein contents and their activities in adult rat cardiomyocytes. Increases in PLC beta(1), beta(3), gamma(1), and delta(1) activities and gene expression in response to NE were prevented by prazosin, an alpha(1)-adrenoceptor (AR) antagonist. Furthermore, mRNA levels for c-Fos and c-Jun, unlike other transcriptional factors, were increased by both NE and phenylephrine, a specific alpha(1)-AR agonist. Increases in c-Fos and c-Jun gene expression due to NE were attenuated by both prazosin and a PLC inhibitor, U73122. Activation of protein kinase C (PKC) with phorbol myristate acetate increased c-Fos and c-Jun mRNA, whereas inhibition of PKC with bisindolylmaleimide as well as inhibition of extracellular signal-regulated kinases (ERK) 1/2 with PD98059 abolished the NE-induced increase in c-Fos and c-Jun gene expression. Reduction of c-Jun phosphorylation by SP600125, an inhibitor of JNK activity, was associated with an attenuation of the NE-induced increases in PLC gene expression. It is suggested that c-Fos and c-Jun gene expression is regulated by PLC in adult cardiomyocytes through a PKC- and ERK1/2-dependent pathway.
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Affiliation(s)
- Tushi Singal
- Department of Physiology, Faculty of Medicine, Institute of Cardiovascular Sciences, St. Boniface Hospital Research Centre, University of Manitoba, Winnipeg, Canada
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Schlüter KD, Wenzel S. Angiotensin II: a hormone involved in and contributing to pro-hypertrophic cardiac networks and target of anti-hypertrophic cross-talks. Pharmacol Ther 2008; 119:311-25. [PMID: 18619489 DOI: 10.1016/j.pharmthera.2008.05.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 05/30/2008] [Indexed: 12/23/2022]
Abstract
Angiotensin II (Ang II) plays a major role in the progression of myocardial hypertrophy to heart failure. Inhibiting the angiotensin converting enzyme (ACE) or blockade of the corresponding Ang II receptors is used extensively in clinical practice, but there is scope for refinement of this mode of therapy. This review summarizes the current understanding of the direct effects of Ang II on cardiomyocytes and then focus particularly on interaction of components of the renin-angiotensin system with other hormones and cytokines. New findings described in approximately 400 papers identified in the PubMed database and published during the 2.5 years are discussed in the context of previous relevant literature. The cardiac action of Ang II is influenced by the activity of different isoforms of ACE leading to different amounts of Ang II by comparison with other angiotensinogen-derived peptides. The effect of Ang II is mediated by at least two different AT receptors that are differentially expressed in cardiomyocytes from neonatal, adult and failing hearts. The intracellular effects of Ang II are influenced by nitric oxide (NO)/cGMP-dependent cross talk and are mediated by the release of autocrine factors, such as transforming growth factor (TGF)-beta1 and interleukin (IL)-6. Besides interactions with cytokines, Ang II is involved in systemic networks including aldosterone, parathyroid hormone and adrenomedullin, which have their own effects on cardiomyocytes that modify, amplify or antagonize the primary effect of Ang II. Finally, hyperinsulemia and hyperglycaemia influence Ang II-dependent processes in diabetes and its cardiac sequelae.
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Affiliation(s)
- K-D Schlüter
- Physiologisches Institut, Justus-Liebig-Universität Giessen, Germany.
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7
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Osadchii OE. Cardiac hypertrophy induced by sustained β-adrenoreceptor activation: pathophysiological aspects. Heart Fail Rev 2007; 12:66-86. [PMID: 17387610 DOI: 10.1007/s10741-007-9007-4] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2007] [Accepted: 02/21/2007] [Indexed: 10/23/2022]
Abstract
Cardiac hypertrophy is promoted by adrenergic over-activation and represents an independent risk factor for cardiovascular morbidity and mortality. The basic knowledge about mechanisms by which sustained adrenergic activation promotes myocardial growth, as well as understanding how structural changes in hypertrophied myocardium could affect myocardial function has been acquired from studies using an animal model of chronic systemic beta-adrenoreceptor agonist administration. Sustained beta-adrenoreceptor activation was shown to enhance the synthesis of myocardial proteins, an effect mediated via stimulation of myocardial growth factors, up-regulation of nuclear proto-oncogenes, induction of cardiac oxidative stress, as well as activation of mitogen-activated protein kinases and phosphatidylinositol 3-kinase. Sustained beta-adrenoreceptor activation contributes to impaired cardiac autonomic regulation as evidenced by blunted parasympathetically-mediated cardiovascular reflexes as well as abnormal storage of myocardial catecholamines. Catecholamine-induced cardiac hypertrophy is associated with reduced contractile responses to adrenergic agonists, an effect attributed to downregulation of myocardial beta-adrenoreceptors, uncoupling of beta-adrenoreceptors and adenylate cyclase, as well as modifications of downstream cAMP-mediated signaling. In compensated cardiac hypertrophy, these changes are associated with preserved or even enhanced basal ventricular systolic function due to increased sarcoplasmic reticulum Ca(2+) content and Ca(2+)-induced sarcoplasmic reticulum Ca(2+) release. The increased availability of Ca(2+) to maintain cardiomyocyte contraction is attributed to prolongation of the action potential due to inhibition of the transient outward potassium current as well as stimulation of the reverse mode of the Na(+)-Ca(2+) exchange. Further progression of cardiac hypertrophy towards heart failure is due to abnormalities in Ca(2+) handling, necrotic myocardial injury, and increased myocardial stiffness due to interstitial fibrosis.
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Affiliation(s)
- Oleg E Osadchii
- Cardiology Group, School of Clinical Sciences, University Clinical Departments, University of Liverpool, The Duncan Building, Daulby Street, Liverpool, L69 3GA, UK.
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González-Cuello A, Milanés MV, Castells MT, Laorden ML. Morphine withdrawal-induced c-fos expression in the heart: a peripheral mechanism. Eur J Pharmacol 2004; 487:117-24. [PMID: 15033383 DOI: 10.1016/j.ejphar.2004.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Revised: 12/03/2003] [Accepted: 01/21/2004] [Indexed: 11/23/2022]
Abstract
We previously demonstrated that hyperactivity of cardiac noradrenergic pathways observed during morphine withdrawal is mediated by peripheral mechanisms. In the present study, naloxone methiodide (quaternary derivative of naloxone that does not cross the blood-brain barrier) and naloxone were administered to morphine-dependent rats and Fos immunostaining was used as a reflection of neuronal activity. Dependence on morphine was induced by 7-day chronic subcutaneous (s.c.) implantation of six morphine pellets (75 mg). Morphine withdrawal was precipitated by administration of naloxone methiodide (5 mg/kg, s.c.) or naloxone (5 mg/kg, s.c.) on day 8. Using immunohistochemical staining of Fos, present results indicate that the administration of naloxone methiodide or naloxone to morphine-dependent rats induced marked Fos immunoreactivity within the cardiomyocyte nuclei. Moreover, Western blot analysis revealed a peak expression of c-fos in the right and left ventricles after naloxone methiodide- or naloxone-precipitated withdrawal. In addition, in the hypothalamic paraventricular nucleus (PVN), Fos expression was increased after naloxone-but not after naloxone methiodide-administration to morphine-dependent rats. These results suggest that the activation of c-fos expression observed during morphine withdrawal in the heart is due to intrinsic mechanisms outside the central nervous system (CNS).
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Affiliation(s)
- Ana González-Cuello
- Department of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
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González-Cuello A, Milanés MV, Castells MT, Laorden ML. Activation of c-fos expression in the heart after morphine but not U-50,488H withdrawal. Br J Pharmacol 2003; 138:626-33. [PMID: 12598416 PMCID: PMC1573701 DOI: 10.1038/sj.bjp.0705093] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. In the present work we have studied in the heart the expression of Fos, the protein product of the c-fos proto-oncogene and the adaptive changes in noradrenergic neurons after naloxone or nor-binaltorphimine (nor-BNI) administration to morphine or U-50,488H pretreated rats. 2. Male rats were implanted with placebo (naïve) or morphine (tolerant/dependent) pellets for 7 days. On day 8 rats received saline s.c., naloxone (5 mg kg(-1) s.c.) or nor-BNI (5 mg kg(-1) i.p.). Other groups of rats were rendered tolerant/dependent on U-50,488H by injecting the drug twice daily (15 mg kg(-1) i.p.) for 4 days. Control animals received saline. On day 5 the animals were injected with vehicle i.p. or nor-BNI (5 mg kg(-1) i.p.). 3. Using immunohistochemical staining of Fos, present results indicate that morphine withdrawal induced marked Fos immunoreactivity (Fos-IR) within the cardiomyocyte nuclei. Moreover, Western blots analysis revealed a peak expression of c-fos in right and left ventricle after naloxone induced withdrawal in parallel with an increase in noradrenaline (NA) turnover. 4. However, after nor-BNI administration to rats chronically treated with U-50,488H, we found a decrease in the NA turnover. In addition, the administration of nor-BNI to rats chronically treated with U-50,488H or morphine did not induce modifications in the Fos-IR, in the heart. 5. These results demonstrated that morphine withdrawal induces the expression of Fos protein, as well as an enhancement of noradrenergic activity in the heart. In contrast to morphine U-50,488 withdrawal produces no changes in Fos-IR in parallel with a decrease in NA turnover, indicating that the kappa-opioid receptors are not involved in the molecular adaptive mechanisms responsible for the development of opioid dependence in the heart.
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Affiliation(s)
- Ana González-Cuello
- Equip of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
| | - M Victoria Milanés
- Equip of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
| | - M Teresa Castells
- Department of Cell Biology, University School of Medicine, Murcia, Spain
| | - M Luisa Laorden
- Equip of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
- Author for correspondence:
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Hammerschmidt S, Bell M, Büchler N, Wahn H, Remkes H, Lohse MJ, Neubauer S. Acute changes of myocardial creatine kinase gene expression under beta-adrenergic stimulation. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1502:471-80. [PMID: 11068189 DOI: 10.1016/s0925-4439(00)00070-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Creatine kinase (CK) plays a crucial role in myocardial energy metabolism. Alterations in CK gene expression are found in hypertrophied and failing heart, but the mechanisms behind these changes are unclear. This study tests the hypothesis that increased adrenergic stimulation, which is observed in heart failure, induces changes of myocardial CK-activity, -isoenzyme distribution and -gene expression that are characteristic of the failing and hypertrophied heart. Isolated rat hearts were perfused (constant pressure of 80 mmHg) with red cell suspensions. Following a 20-min warm-up period, perfusion for 3 h with 10(-8) M (iso 3 h) or without (control 3 h) isoproterenol was started or experiments were immediately terminated (control 0 h). Left ventricular tissue was analyzed for total CK-activity, CK-isoenzyme distribution and, by use of quantitative RT-PCR, for B-CK, M-CK, mito-CK and GAPDH- (as internal standard) mRNA. After beta-adrenergic stimulation (iso 3 h) but not after control perfusion (control 3 h) a roughly threefold increase in B-CK mRNA levels and a decrease in M-CK mRNA levels by 18% was found. There were no significant differences among the three groups in total CK-activity and in distribution of CK-MM, CK-BB, CK-MB and mito-CK. Thus, beta-adrenergic stimulation induces a switch in CK gene expression from M-CK to B-CK, which is characteristic for the hypertrophied and failing heart. This may be interpreted as an adaptive mechanism making energy transduction via CK more efficient at times of increased metabolic demand.
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Affiliation(s)
- S Hammerschmidt
- Department of Medicine Pharmacology, University of Würzburg, Würzburg, Germany.
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11
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Beattie JH, Wood AM, Trayhurn P, Jasani B, Vincent A, McCormack G, West AK. Metallothionein is expressed in adipocytes of brown fat and is induced by catecholamines and zinc. Am J Physiol Regul Integr Comp Physiol 2000; 278:R1082-9. [PMID: 10749798 DOI: 10.1152/ajpregu.2000.278.4.r1082] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Metallothionein (MT) is thought to have an antioxidant function and is strongly expressed during activation of thermogenesis and increased oxidative stress in brown adipose tissue (BAT). Localization and regulation of MT expression in BAT was therefore investigated in rats and mice. Immunohistochemical analysis of BAT from rats exposed to 4 degrees C for 24 h showed that MT and uncoupling protein 1 (UCP1) were coexpressed in differentiated adipocytes, and both cytoplasmic and nuclear localization of MT was observed. Cold induction of MT-1 expression in BAT was also observed in mice. Administration of norepinephrine to rats and isoproterenol to mice stimulated MT and UCP1 expression in BAT, implying a sympathetically mediated pathway for MT induction. In mice, zinc, and particularly dexamethasone, induced MT-2 expression in BAT and liver. Surprisingly, zinc also induced UCP1 in BAT, suggesting that elevated zinc may induce thermogenesis. We conclude that expression of MT in mature brown adipocytes upon beta-adrenoceptor activation is consistent with a role in protecting against physiological oxidative stress or in facilitating the mobilization or utilization of energy reserves.
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Affiliation(s)
- J H Beattie
- Trace Element and Gene Expression Group, United Kingdom.
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12
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Rose RW, West AK, Ye JM, McCormick GH, Colquhoun EQ. Nonshivering thermogenesis in a marsupial (the tasmanian bettong Bettongia gaimardi) is not attributable to brown adipose tissue. Physiol Biochem Zool 1999; 72:699-704. [PMID: 10603333 DOI: 10.1086/316709] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The Tasmanian bettong (Bettongia gaimardi, a marsupial) is a rat-kangaroo that increases nonshivering thermogenesis (NST) in response to norepinephrine (NE). This study attempted to assess whether brown adipose tissue (BAT), a specialized thermogenic effector, is involved in NST in the bettong. Regulatory NST, indicated by resting oxygen consumption (Vo2) of the whole body, was measured under conscious conditions at 20 degrees C with various stimuli: cold (4 degrees -5 degrees C) or warm (25 degrees C) acclimation, NE injection, and the beta3-adrenoceptor agonist (BRL) 37344. In line with the functional studies in vivo, the presence of BAT was evaluated by examining the expression of the uncoupling protein 1 (UCP1) with both rat cDNA and oligonucleotide probes. Both NE and BRL 37344 significantly stimulated NST in the bettong. After cold acclimation of the animals (at 4 degrees -5 degrees C for 2 wk), the resting Vo2 was increased by 15% and the thermogenic effect of NE was enhanced; warm-acclimated animals showed a slightly depressed response. However, no expression of UCP1 was detected in bettongs either before or after cold exposure (2 wk). These data suggest that the observed NST in the marsupial bettong is not attributable to BAT.
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Affiliation(s)
- R W Rose
- School of Zoology, University of Tasmania, Hobart, Tasmania 7001, Australia.
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Ogino K, Cai B, Gu A, Kohmoto T, Yamamoto N, Burkhoff D. Factors contributing to pressure overload-induced immediate early gene expression in adult rat hearts in vivo. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:H380-7. [PMID: 10409218 DOI: 10.1152/ajpheart.1999.277.1.h380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We determined the contributions of angiotensin II type 1 receptor (AT(1)) stimulation, adrenergic stimulation, and autonomic activation to pressure overload-induced c-fos expression in the adult rat heart in vivo. c-fos expression was increased in pressure-overloaded hearts created by aortic banding compared with sham-operated rats (458 +/- 100% vs. sham, P < 0.05). GR-138950, a selective AT(1) antagonist, did not blunt this expression (banding vs. banding + GR-138950: 458 +/- 100% vs. 500 +/- 125%, not significant). Atropine and hexamethonium partially decreased c-fos expression (banding vs. banding + atropine/hexamethonium: 700 +/- 67% vs. 400 +/- 67%, P < 0.05). Phentolamine had no significant effect on c-fos expression; however, propranolol inhibited the expression (banding vs. banding + propranolol: 492 +/- 108% vs. 154 +/- 15%, P < 0.05). The inhibition by propranolol was independent of the decreases in heart rate. Thus factors contributing to pressure overload-induced c-fos expression in adult rat hearts in vivo are different from those in neonatal myocytes in vitro undergoing stretch.
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MESH Headings
- Animals
- Gene Expression
- Genes, Immediate-Early/genetics
- Genes, fos/genetics
- Myocardium/cytology
- Pressure
- Rats
- Rats, Wistar
- Receptor, Angiotensin, Type 1
- Receptor, Angiotensin, Type 2
- Receptors, Adrenergic/drug effects
- Receptors, Adrenergic/physiology
- Receptors, Angiotensin/physiology
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Affiliation(s)
- K Ogino
- Department of Medicine, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA.
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Saadane N, Alpert L, Chalifour LE. Expression of immediate early genes, GATA-4, and Nkx-2.5 in adrenergic-induced cardiac hypertrophy and during regression in adult mice. Br J Pharmacol 1999; 127:1165-76. [PMID: 10455263 PMCID: PMC1566134 DOI: 10.1038/sj.bjp.0702676] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Adrenoreceptor agonists induce a hypertrophic phenotype in vitro and in vivo. To investigate the molecular remodeling in chronic cardiac hypertrophy we infused adult male mice with vehicle. isoproterenol, phenylephrine or both agonists for 3, 7 or 14 days. All drugs increased cardiac mass. After minipump removal cardiac mass regressed to control levels within 7 days after PE and ISO treatment whereas ISO + PE treated hearts were incompletely regressed. ANF and beta-MHC, but not alpha-MHC, expression were increased by agonists at all time points. GATA-4, Nkx-2.5, Egr-1, c-jun and c-fos expression were increased after 3, 7 and 14 days of treatment. Expression was greatest after ISO+PE> >ISO>PE>vehicle infusion suggesting a synergistic effect of adrenoreceptor stimulation and indicating a greater effect of beta- than alpha-adrenergic action in vivo. After PE or ISO drug withdrawal the HW/BW was normal and Egr-1, c-jun, c-fos and GATA-4, but not Nkx2.5, expression dropped to control levels. HW/BW regression was incomplete after ISO+PE and elevated levels of Egr-1, c-jun and Nkx2.5 expression remained. A hydralazine-mediated reduction in blood pressure had no effect on the agonist-induced cardiac hypertrophy or gene expression. In conclusion, we found that continued agonist stimulation, and not blood pressure. is responsible for the maintained increase in gene expression. Further, we found the decrease in gene expression in the regression after drug withdrawal was gene specific.
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Affiliation(s)
- Nacéra Saadane
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis–Jewish General Hospital, 3755 chemin Côte Sainte Catherine, Montréal, Québec, Canada, H3T 1E2
| | - Lesley Alpert
- Department of Pathology, Sir Mortimer B. Davis–Jewish General Hospital, 3755 chemin Côte Sainte Catherine, Montréal, Québec, Canada, H3T 1E2
| | - Lorraine E Chalifour
- Lady Davis Institute for Medical Research, Sir Mortimer B. Davis–Jewish General Hospital, 3755 chemin Côte Sainte Catherine, Montréal, Québec, Canada, H3T 1E2
- Division of Experimental Medicine, Department of Medicine, McGill University, Montréal, Québec, Canada, H3A 1A3
- Author for correspondence:
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Abstract
Cardiomyocytes of adult myocardium increase their cellular mass in response to growth stimuli. They undergo hypertrophic growth but they do not proliferate in contrast to immature cardiomyocytes. Growth stimuli of the adult cardiomyocytes include classical growth hormones, various neuroendocrine factors, and the increase in mechanical load. The signal transduction of alpha1-adrenoceptor stimulation has been investigated in greatest detail and may therefore be taken as a reference for other humoral stimuli. It involves the activation of protein kinase C (PKC) and, downstream of PKC activation, of two separate signaling pathways, one including the mitogen-activated protein kinase and another including PI3-kinase and p70(s6k) as key steps. Activation of the first pathway leads to re-expression of fetal genes, activation of the second pathway to a general activation of protein synthesis, and cellular growth. In neonatal cardiomyocytes, mechanical stretch causes growth by an activation of an autocrine mechanism including angiotensin II and endothelin. This mechanism does not operate, however, in adult cardiomyocytes. A mechanism of mechanotransduction has not yet been identified on adult cardiomyocytes but integrins may play a part. In microgravity, the scenario of myocardial growth stimulation is altered. On the systemic level, there are changes in hemodynamic and neuroendocrine regulation that exert indirect effects on the myocardium. Microgravity may also exert a direct cellular effect by the absence of a constant gravitational load component.
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Affiliation(s)
- K D Schlüter
- Physiologisches Institut, Justus-Liebig-Universität, D-35392 Giessen, Germany
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Fujitani N, Kawaguchi N, Toda S, Matsumura S, Kimura H, Onishi S. Immunocytochemical detection of enhanced expression of c-myc protein in the heart of cardiomyopathic hamster. Mol Cell Biochem 1997; 169:73-8. [PMID: 9089633 DOI: 10.1023/a:1006829700747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An immunocytochemical study was performed to examine the expression of cellular c-myc protein in the heart of 30-, 120- and 180-day-old cardiomyopathic Syrian UM-X7.1 hamsters. The heart of age- and sex-matched BIO-RB hamster was used as normal control. In paraffin sections, an immunostaining for c-myc was markedly increased in cytoplasm of cells from the UM-X7.1 heart as compared with that of the BIO-RB heart which showed a weak staining. However, c-myc was localized in nuclei of cells in frozen sections of the heart. Specific cell types of the heart were differentiated with anti-vimentin, and we found that the increased expression of c-myc was present in nuclei of muscle cells of the UM-X7.1 myocardium. A quantitative study of c-myc-positive nuclei of muscle and nonmuscle cells was carried out by a video micrometer. The mean number of c-myc-positive nuclei of muscle cells was significantly higher in the cardiomyopathic heart than in the control heart from hamsters of all ages studied. These results suggest that the increase of c-myc protein may relate to the pathological state or pathogenesis of the hereditary cardiomyopathy.
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Affiliation(s)
- N Fujitani
- Department of Legal Medicine, Kurume University School of Medicine, Fukuoka, Japan
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Affiliation(s)
- P S Pollack
- Department of Medicine, Temple University School of Medicine, Philadelphia, PA 19140
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Wiesner RJ, Aschenbrenner V, Rüegg JC, Zak R. Coordination of nuclear and mitochondrial gene expression during the development of cardiac hypertrophy in rats. THE AMERICAN JOURNAL OF PHYSIOLOGY 1994; 267:C229-35. [PMID: 7519396 DOI: 10.1152/ajpcell.1994.267.1.c229] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We studied the coordination of nuclear and mitochondrial gene expression during cardiac hypertrophy following aortic stenosis or thyroid hormone treatment in rats. We measured mRNA levels for representative subunits of cytochrome-c oxidase, two encoded by mitochondrial DNA and two encoded by the nucleus, as well as the levels of one mitochondrial rRNA. In both models of hypertrophy, an increase of total tissue RNA, reflecting mainly cytosolic ribosomes, accompanied the increase in ventricular weight. Relative levels of mitochondrial rRNA remained unchanged, indicating a net synthesis of mitochondrial ribosomes as well. In both models, cytochrome-c oxidase activity and nuclear-encoded mRNAs remained fairly constant, whereas levels of mitochondrial mRNAs were transiently decreased 24 h after the growth stimulus. We conclude that, in the initial phase of hypertrophy, the signal regulating the synthesis of mitochondrial rRNA is synchronized with nuclear gene expression, whereas the signal regulating mitochondrial mRNA synthesis is not. We postulate that differential regulation of mitochondrial transcription and premature termination of the polycistronic transcript (the latter giving rise to the mitochondrial rRNAs) account for the observed results.
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Affiliation(s)
- R J Wiesner
- Department of Medicine, University of Chicago, Illinois 60637
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Okazaki M, Hu ZW, Fujinaga M, Hoffman BB. Alpha 1 adrenergic receptor-induced c-fos gene expression in rat aorta and cultured vascular smooth muscle cells. J Clin Invest 1994; 94:210-8. [PMID: 8040263 PMCID: PMC296299 DOI: 10.1172/jci117309] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
While growth of blood vessels is important in hypertension, relatively little is known about the contribution of catecholamines. Using isolated rat aorta and cultured smooth muscle cells, we examined adrenergic stimulation of gene expression. Phenylephrine, a selective alpha 1 adrenergic receptor agonist, caused a rapid and transient increase in c-fos mRNA accumulation which was inhibited by prazosin, an alpha 1 receptor antagonist. Similarly, phenylephrine stimulated c-jun and c-myc mRNA accumulation. Chloroethyl-clonidine, a compound which irreversibly blocks alpha 1B receptors, completely blocked the phenylephrine-induced increase in c-fos mRNA. RNase protection experiments demonstrated that rat aorta prominently expressed mRNA for alpha 1B and alpha 1A/D receptors. Phenylephrine-induced c-fos mRNA was partially inhibited by H-7, a protein kinase C inhibitor, and by nifedipine, a Ca2+ channel blocker; these two compounds together had additive effects. In situ hybridization showed that expression of c-fos mRNA induced by phenylephrine was localized to aorta's medial layer. These results suggest that alpha 1 receptor-induced increase in c-fos mRNA in aorta is mediated by a chloroethyl-clonidine-sensitive receptor subtype signaling via increasing intracellular Ca2+ concentrations and activating protein kinase C.
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Affiliation(s)
- M Okazaki
- Department of Medicine, Stanford University School of Medicine, California
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Hannan RD, Stennard FA, West AK. Localization of c-myc protooncogene expression in the rat heart in vivo and in the isolated, perfused heart following treatment with norepinephrine. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1217:281-90. [PMID: 8148373 DOI: 10.1016/0167-4781(94)90287-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have investigated the expression of the protooncogene c-myc in rat hearts following exposure to norepinephrine, both in vivo and in isolated perfused preparations. Both chronic and acute norepinephrine treatment produced a rapid, transient elevation of c-myc mRNA in adult rat hearts, but chronic infusion produced a second, larger increase. This expression profile was characteristic for c-myc since it was not found for four other protooncogenes. In the isolated, perfused heart, addition of norepinephrine to the perfusion buffer and elevation of perfusion pressure separately increase c-myc mRNA suggesting both direct hormonal and hemodynamic factors might be important in vivo. Immunocytochemistry showed that Myc protein accumulated predominantly in the nuclei of non-myocyte cells following norepinephrine treatment indicating that expression at the mRNA level culminated in protein synthesis. These findings suggest that the c-myc expression observed in the hypertrophying adult heart following exposure to norepinephrine may be associated with proliferating cells like fibroblasts rather than cardiomyocytes.
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Affiliation(s)
- R D Hannan
- Department of Biochemistry, University of Tasmania, Hobart, Australia
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Brand T, Sharma HS, Fleischmann KE, Duncker DJ, McFalls EO, Verdouw PD, Schaper W. Proto-oncogene expression in porcine myocardium subjected to ischemia and reperfusion. Circ Res 1992; 71:1351-60. [PMID: 1385005 DOI: 10.1161/01.res.71.6.1351] [Citation(s) in RCA: 119] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The molecular basis of myocardial adaptation to ischemia and reperfusion is poorly understood. It is thought that nuclear proto-oncogenes act as third messengers, converting cytoplasmic signal transduction into long-term changes of gene expression. We studied the expression of six nuclear proto-oncogenes (Egr-1, c-fos, fosB, c-jun, junB, and c-myc) in myocardium subjected to ischemia and reperfusion in anesthetized pigs. Stunning was achieved by two 10-minute left anterior descending coronary artery occlusions separated by 30 minutes of reperfusion. Hearts were excised after the first occlusion, after the first reperfusion, and at 30, 120, 150, and 210 minutes of reperfusion after the second occlusion. Total RNA was prepared from stunned as well as normally perfused myocardial tissue and subjected to Northern blotting. The response of the six nuclear proto-oncogenes varied.fosB gene expression was never detected. The c-myc gene was expressed, but its level was unchanged by ischemia. c-jun expression was slightly increased by ischemia (3.1 +/- 0.6-fold). The c-fos, Egr-1, and junB genes were highly induced, being fivefold to sevenfold higher in experimental than in control tissue. In three animals pretreated with the beta 1-antagonist metoprolol and then subjected to the above experimental protocol, the induction of proto-oncogenes was similar to that in nonblocked controls. Our results show that the myocardial adaptive response to ischemic stress includes the induction of at least four transcription factors that may be further operative in repair processes and angiogenesis.
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Affiliation(s)
- T Brand
- Department of Experimental Cardiology, Max Planck Institute of Physiological and Clinical Research, Bad Neuheim, FRG
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