151
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Colak D, Kaya N, Al-Zahrani J, Al Bakheet A, Muiya P, Andres E, Quackenbush J, Dzimiri N. Left ventricular global transcriptional profiling in human end-stage dilated cardiomyopathy. Genomics 2009; 94:20-31. [PMID: 19332114 PMCID: PMC4152850 DOI: 10.1016/j.ygeno.2009.03.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 02/17/2009] [Accepted: 03/17/2009] [Indexed: 02/07/2023]
Abstract
We employed ABI high-density oligonucleotide microarrays containing 31,700 sixty-mer probes (representing 27,868 annotated human genes) to determine differential gene expression in idiopathic dilated cardiomyopathy (DCM). We identified 626 up-regulated and 636 down-regulated genes in DCM compared to controls. Most significant changes occurred in the tricarboxylic acid cycle, angiogenesis, and apoptotic signaling pathways, among which 32 apoptosis- and 13 MAPK activity-related genes were altered. Inorganic cation transporter, catalytic activities, energy metabolism and electron transport-related processes were among the most critically influenced pathways. Among the up-regulated genes were HTRA1 (6.9-fold), PDCD8(AIFM1) (5.2) and PRDX2 (4.4) and the down-regulated genes were NR4A2 (4.8), MX1 (4.3), LGALS9 (4), IFNA13 (4), UNC5D (3.6) and HDAC2 (3) (p<0.05), all of which have no clearly defined cardiac-related function yet. Gene ontology and enrichment analysis also revealed significant alterations in mitochondrial oxidative phosphorylation, metabolism and Alzheimer's disease pathways. Concordance was also confirmed for a significant number of genes and pathways in an independent validation microarray dataset. Furthermore, verification by real-time RT-PCR showed a high degree of consistency with the microarray results. Our data demonstrate an association of DCM with alterations in various cellular events and multiple yet undeciphered genes that may contribute to heart muscle disease pathways.
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Affiliation(s)
- Dilek Colak
- Department of Biostatistics, Epidemiology and Scientific Computing, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia
| | - Namik Kaya
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia
| | - Jawaher Al-Zahrani
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia
| | - Albandary Al Bakheet
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia
| | - Paul Muiya
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia
| | - Editha Andres
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia
| | - John Quackenbush
- Department of Biostatistics and Computational Biology; Dana-Farber Cancer Institute, Boston, MA, USA
| | - Nduna Dzimiri
- Department of Genetics, King Faisal Specialist Hospital and Research Centre, P.O. Box 3354, Riyadh 11211, Saudi Arabia
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152
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Greaser ML. Stressing the giant: a new approach to understanding dilated cardiomyopathy. J Mol Cell Cardiol 2009; 47:347-9. [PMID: 19555694 DOI: 10.1016/j.yjmcc.2009.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 06/12/2009] [Indexed: 11/29/2022]
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153
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Mutations in the ANKRD1 gene encoding CARP are responsible for human dilated cardiomyopathy. Eur Heart J 2009; 30:2128-36. [DOI: 10.1093/eurheartj/ehp225] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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154
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Mathur MC, Kobayashi T, Chalovich JM. Some cardiomyopathy-causing troponin I mutations stabilize a functional intermediate actin state. Biophys J 2009; 96:2237-44. [PMID: 19289050 DOI: 10.1016/j.bpj.2008.12.3909] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 12/08/2008] [Accepted: 12/12/2008] [Indexed: 11/19/2022] Open
Abstract
We examined four cardiomyopathy-causing mutations of troponin I that appear to disturb function by altering the distribution of thin filament states. The R193H (mouse) troponin I mutant had greater than normal actin-activated myosin-S1 ATPase activity in both the presence and absence of calcium. The rate of ATPase activity was the same as that of the wild-type at near-saturating concentrations of the activator, N-ethylmaleimide-S1. This mutant appeared to function by stabilizing the active state of thin filaments. Mutations D191H, R146G, and R146W had lower ATPase activities in the presence of calcium, but higher activities in the absence of calcium. These effects were most pronounced with mutations at position 146. For all three mutants the rates were similar to those of the wild-type at near-saturating concentrations of N-ethylmaleimide-S1. These results, combined with previous results, show that any alteration in the normal distribution of actomyosin states is capable of producing cardiomyopathy. The results of the D191H, R146G, and R146W mutations are most readily explained if the intermediate state of regulated actin has a unique function. The intermediate state appears to have an ability to accelerate the rate of ATP hydrolysis by myosin that exceeds that of the inactive state.
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Affiliation(s)
- Mohit C Mathur
- Department of Biochemistry and Molecular Biology, Brody School of Medicine, East Carolina University, Greenville, North Carolina, USA
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155
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Finding disease-specific coordinated functions by multi-function genes: insight into the coordination mechanisms in diseases. Genomics 2009; 94:94-100. [PMID: 19427897 DOI: 10.1016/j.ygeno.2009.05.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Accepted: 05/04/2009] [Indexed: 12/31/2022]
Abstract
We developed an approach using multi-function disease genes to find function pairs whose co-deregulation might induce a disease. Analyzing cancer genes, we found many cancer-specific coordinated function pairs co-deregulated by dysfunction of multi-function genes and other molecular changes in cancer. Studying two subtypes of cardiomyopathy, we found they show certain consistency at the functional coordination level. Our approach can also provide important information for finding novel disease genes as well as their mechanisms in diseases.
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156
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Arimura T, Inagaki N, Hayashi T, Shichi D, Sato A, Hinohara K, Vatta M, Towbin JA, Chikamori T, Yamashina A, Kimura A. Impaired binding of ZASP/Cypher with phosphoglucomutase 1 is associated with dilated cardiomyopathy. Cardiovasc Res 2009; 83:80-8. [PMID: 19377068 DOI: 10.1093/cvr/cvp119] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
AIMS Z-band alternatively spliced PDZ-motif protein (ZASP)/Cypher is a Z-disc component of which several dilated cardiomyopathy (DCM)-associated mutations have been reported. Most of the mutations were found in exons 4 and 10 of ZASP/Cypher gene LDB3 and both exons were expressed preferentially in the heart. The aim of this study was to investigate the functional alteration of ZASP/Cypher caused by the DCM-associated mutations. METHODS AND RESULTS The yeast-two-hybrid method was used to identify the protein bound to a domain encoded by exon 4 of LDB3. Interaction of ZASP/Cypher with the binding protein was investigated in relation to the functional alterations caused by LDB3 mutations. Localization of the ZASP/Cypher-binding protein was examined at the cellular level in rat cardiomyocytes. Phosphoglucomutase 1 (PGM1), a metabolic enzyme involved in glycolysis and gluconeogenesis, was identified as a protein interacting with ZASP/Cypher. PGM1 bound to ZASP/Cypher at the domains encoded by exons 4 and 10. Two LDB3 mutations in exon 4 (Ser189Leu and Thr206Ile) and another mutation in exon 10 (Ile345Met) reduced the binding to PGM1. PGM1 showed diffuse localization in the cytoplasm of rat cardiomyocytes under standard culture conditions, and distribution at the Z-discs was observed under stressed culture conditions. Binding of endogenous PGM1 and ZASP/Cypher was found to be enhanced by stress in rat cardiomyocytes. CONCLUSION ZASP/Cypher anchors PGM1 to Z-disc under conditions of stress. The impaired binding of PGM1 to ZASP/Cypher might be involved in the pathogenesis of DCM.
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Affiliation(s)
- Takuro Arimura
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45 Bunkyo-Ku, Tokyo, Japan
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157
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DiMichele LA, Hakim ZS, Sayers RL, Rojas M, Schwartz RJ, Mack CP, Taylor JM. Transient expression of FRNK reveals stage-specific requirement for focal adhesion kinase activity in cardiac growth. Circ Res 2009; 104:1201-8. [PMID: 19372463 DOI: 10.1161/circresaha.109.195941] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Focal adhesion kinase (FAK) is strongly activated by integrins and growth factors and is essential for embryonic development. We previously showed that the C terminus of FAK is expressed as a separate protein termed FAK-related nonkinase (FRNK) in a smooth muscle cell-selective fashion and that FRNK functions to buffer FAK-dependent signals. We now show that FRNK is also transiently expressed in the neonatal myocardium, with peak levels occurring 5 to 7 days postnatal, just before cell cycle withdrawal. Using novel mouse models, we demonstrate that cardiac-selective expression of FRNK (leading to inhibition of FAK) starting at embryonic day 10.5 leads to a severe ventricular noncompaction defect associated with reduced cardiomyocyte proliferation. Remarkably, postnatal expression of nearly identical levels of FRNK is well tolerated and does not affect viability or anabolic cardiac growth. Nonetheless, FRNK expression in the adult heart does attenuate pathological cardiac hypertrophy following aortic banding, confirming and extending our previous data that this compensatory response is blunted in FAK null hearts. Our mechanistic studies in cultured neonatal cardiomyocytes reveal that FRNK expression induces p38/p27(kip)-dependent cell cycle withdrawal and attenuates extracellular signal-regulated kinase-dependent hypertrophic growth. These findings indicate that dynamic expression of FRNK in the neonatal heart may function to promote cardiomyocyte quiescence in an environment that is particularly rich in growth factors and growth promoting extracellular matrices.
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Affiliation(s)
- Laura A DiMichele
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
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158
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Abstract
MicroRNAs (miRNAs) are a class of non-coding regulatory RNAs of approximately 22 nucleotides in length. miRNAs are highly conserved across a number of species, including plants, worms and humans. miRNAs regulate gene expression post-transcriptionally, primarily by associating with the 3' untranslated region (UTR) of their regulatory target mRNAs. Recent work has begun to reveal roles for miRNAs in a wide range of biological processes, including cell proliferation, differentiation and apoptosis. miRNAs are expressed in cardiac and skeletal muscle, and dysregulated miRNA expression has been correlated with muscle-related disorders. Genetic studies have identified distinct roles for specific miRNAs during cardiogenesis, cardiac hypertrophy and electrical conduction. Furthermore, conditionally inhibiting the maturation of miRNAs in mouse cardiac and skeletal muscles has revealed that miRNAs are essential for the development and function of those muscles. These previously unrecognized regulators shed new light on the molecular mechanisms that underlie muscle development and pathology, and suggest the potential importance of miRNAs as diagnostic markers and therapeutic targets for muscle-related disease.
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Affiliation(s)
- Jian-Fu Chen
- Department of Cell and Developmental Biology, University of North Carolina, Chapel Hill, NC 27599-7126, USA
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159
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Chiang CS, Huang CH, Chieng H, Chang YT, Chang D, Chen JJ, Chen YC, Chen YH, Shin HS, Campbell KP, Chen CC. The Ca
V
3.2 T-Type Ca
2+
Channel Is Required for Pressure Overload–Induced Cardiac Hypertrophy in Mice. Circ Res 2009; 104:522-30. [DOI: 10.1161/circresaha.108.184051] [Citation(s) in RCA: 131] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Voltage-gated T-type Ca
2+
channels (T-channels) are normally expressed during embryonic development in ventricular myocytes but are undetectable in adult ventricular myocytes. Interestingly, T-channels are reexpressed in hypertrophied or failing hearts. It is unclear whether T-channels play a role in the pathogenesis of cardiomyopathy and what the mechanism might be. Here we show that the α
1H
voltage-gated T-type Ca
2+
channel (Ca
v
3.2) is involved in the pathogenesis of cardiac hypertrophy via the activation of calcineurin/nuclear factor of activated T cells (NFAT) pathway. Specifically, pressure overload–induced hypertrophy was severely suppressed in mice deficient for Ca
v
3.2 (Ca
v
3.2
−/−
) but not in mice deficient for Ca
v
3.1 (Ca
v
3.1
−/−
). Angiotensin II–induced cardiac hypertrophy was also suppressed in Ca
v
3.2
−/−
mice. Consistent with these findings, cultured neonatal myocytes isolated from Ca
v
3.2
−/−
mice fail to respond hypertrophic stimulation by treatment with angiotensin II. Together, these results demonstrate the importance of Ca
v
3.2 in the development of cardiac hypertrophy both in vitro and in vivo. To test whether Ca
v
3.2 mediates the hypertrophic response through the calcineurin/NFAT pathway, we generated Ca
v
3.2
−/−
, NFAT-luciferase reporter mice and showed that NFAT-luciferase reporter activity failed to increase after pressure overload in the Ca
v
3.2
−/−
/NFAT-Luc mice. Our results provide strong genetic evidence that Ca
v
3.2 indeed plays a pivotal role in the induction of calcineurin/NFAT hypertrophic signaling and is crucial for the activation of pathological cardiac hypertrophy.
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Affiliation(s)
- Chien-Sung Chiang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Ching-Hui Huang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Hockling Chieng
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Ya-Ting Chang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Dory Chang
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Ji-Jr Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Yong-Cyuan Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Yen-Hui Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Hee-Sup Shin
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Kevin P. Campbell
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
| | - Chien-Chang Chen
- From the Institute of Biomedical Sciences (C.-S.C., C.-H.H., H.C., Y.-T.C., D.C., J.-J.C., Y.-C.C.,Y.-H.C., C.-C.C.), Academia Sinica, Taipei, Taiwan; Graduate Institute of Life Sciences (C.-H.H., C.-C.C.), National Defense Medical Center, Taipei, Taiwan; Center for Neural Science (H.-S.S.), Korea Institute of Science and Technology, Seoul, Korea; and Department of Physiology and Biophysics and Department of Neurology (K.P.C.), Howard Hughes Medical Institute, University of Iowa, Iowa City
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160
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Maron BJ, Seidman CE, Ackerman MJ, Towbin JA, Maron MS, Ommen SR, Nishimura RA, Gersh BJ. How should hypertrophic cardiomyopathy be classified? ACTA ACUST UNITED AC 2009; 2:81-5; discussion 86. [DOI: 10.1161/circgenetics.108.788703] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Barry J. Maron
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
| | - Christine E. Seidman
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
| | - Michael J. Ackerman
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
| | - Jeffrey A. Towbin
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
| | - Martin S. Maron
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
| | - Steve R. Ommen
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
| | - Rick A. Nishimura
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
| | - Bernard J. Gersh
- From the Hypertrophic Cardiomyopathy Center (B.J.M.), Minneapolis Heart Institute Foundation, Minneapolis, Minn; Department of Genetics (C.E.S.), Harvard Medical School, Boston, Mass; Departments of Medicine and Pediatrics/Divisions of Cardiovascular Diseases and Pediatric Cardiology (M.J.A., S.R.O., R.A.N., B.J.G.), Mayo Clinic, Rochester, Minn; Department of Pediatrics and Cardiology (J.A.T.), Baylor College of Medicine, Houston, Tex; and Hypertrophic Cardiomyopathy Center (M.S.M.), Tufts Medical
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161
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Abstract
The term cardiodynamics refers to dynamic events associated with cardiac contraction and relaxation. The occurring wave of excitement spreads very quickly along the entire atrial musculature and after a brief AV retention it affects all muscle cells of the ventricles. Excitation, that is, the increase in action potentials, precedes the contraction of the myocardium, which follows the 'all or none' rule. Each contraction results in relaxation of the myocardium, so that the contraction and relaxation cycles continually follow each other in succession. The entire cardiodynamics, hemodinamics, i.e. signaling mechanisms of the heart are altered in the remodeling (alternation) condition of the left ventricular myocardium, i.e. the musculature and the whole arterial wall. Remodeling of the cardiac wall and layers of the arterial wall is a negative factor, because it leads to disturbances of the cardiac contraction and relaxation cycles and incites progression of the arterial hypertension, emergence of atherosclerosis and arterial stenosis. Today, the genetic base of the cardiac remodeling is the object of intensive studies. Cardiomyopathies are primary disorders of the myocardium associated with abnormalities of the cardiac wall thickness, the size of chambers, contractions, relaxations, signal conduct and rhythm. They are the major cause of morbidity and mortality for all age groups. Mechanisms of these events on the molecular level will be discussed in the following study.
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162
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Liu X, Ramjiganesh T, Chen YH, Chung SW, Hall SR, Schissel SL, Padera RF, Liao R, Ackerman KG, Kajstura J, Leri A, Anversa P, Yet SF, Layne MD, Perrella MA. Disruption of striated preferentially expressed gene locus leads to dilated cardiomyopathy in mice. Circulation 2008; 119:261-8. [PMID: 19118250 DOI: 10.1161/circulationaha.108.799536] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND The striated preferentially expressed gene (Speg) generates 4 different isoforms through alternative promoter use and tissue-specific splicing. Depending on the cell type, Speg isoforms may serve as markers of striated or smooth muscle differentiation. METHODS AND RESULTS To elucidate function of Speg gene isoforms, we disrupted the Speg gene locus in mice by replacing common exons 8, 9, and 10 with a lacZ gene. beta-Galactosidase activity was detected in cardiomyocytes of the developing heart starting at day 11.5 days post coitum (dpc). beta-Galactosidase activity in other cell types, including vascular smooth muscle cells, did not begin until 18.5 dpc. In the developing heart, protein expression of only Spegalpha and Spegbeta isoforms was present in cardiomyocytes. Homozygous Speg mutant hearts began to enlarge by 16.5 dpc, and by 18.5 dpc, they demonstrated dilation of right and left atria and ventricles. These cardiac abnormalities in the absence of Speg were associated with a cellular hypertrophic response, myofibril degeneration, and a marked decrease in cardiac function. Moreover, Speg mutant mice exhibited significant neonatal mortality, with increased death occurring by 2 days after birth. CONCLUSIONS These findings demonstrate that mutation of the Speg locus leads to cardiac dysfunction and a phenotype consistent with a dilated cardiomyopathy.
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Affiliation(s)
- Xiaoli Liu
- Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA
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163
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Friedrichs F, Zugck C, Rauch GJ, Ivandic B, Weichenhan D, Müller-Bardorff M, Meder B, El Mokhtari NE, Regitz-Zagrosek V, Hetzer R, Schäfer A, Schreiber S, Chen J, Neuhaus I, Ji R, Siemers NO, Frey N, Rottbauer W, Katus HA, Stoll M. HBEGF, SRA1, and IK: Three cosegregating genes as determinants of cardiomyopathy. Genome Res 2008; 19:395-403. [PMID: 19064678 DOI: 10.1101/gr.076653.108] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Human dilated cardiomyopathy (DCM), a disorder of the cardiac muscle, causes considerable morbidity and mortality and is one of the major causes of sudden cardiac death. Genetic factors play a role in the etiology and pathogenesis of DCM. Disease-associated genetic variations identified to date have been identified in single families or single sporadic patients and explain a minority of the etiology of DCM. We show that a 600-kb region of linkage disequilibrium (LD) on 5q31.2-3, harboring multiple genes, is associated with cardiomyopathy in three independent Caucasian populations (combined P-value = 0.00087). Functional assessment in zebrafish demonstrates that at least three genes, orthologous to loci in this LD block, HBEGF, IK, and SRA1, result independently in a phenotype of myocardial contractile dysfunction when their expression is reduced with morpholino antisense reagents. Evolutionary analysis across multiple vertebrate genomes suggests that this heart failure-associated LD block emerged by a series of genomic rearrangements across amphibian, avian, and mammalian genomes and is maintained as a cluster in mammals. Taken together, these observations challenge the simple notion that disease phenotypes can be traced to altered function of a single locus within a haplotype and suggest that a more detailed assessment of causality can be necessary.
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Affiliation(s)
- Frauke Friedrichs
- Division of Cardiology, Angiology and Pulmonology, University Hospital Heidelberg, Heidelberg 69120, Germany
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164
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Affiliation(s)
- Michelle Asha Albert
- From the Center for Cardiovascular Disease Prevention, Donald W. Reynolds Center for Cardiovascular Disease Research, Divisions of Cardiovascular Diseases and of Preventive Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Mass
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165
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Myocardial fibrosis in patients with symptomatic obstructive hypertrophic cardiomyopathy: correlation with echocardiographic measurements, sarcomeric genotypes, and pro-left ventricular hypertrophy polymorphisms involving the renin-angiotensin-aldosterone system. Cardiovasc Pathol 2008; 18:262-8. [PMID: 18835191 DOI: 10.1016/j.carpath.2008.08.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/13/2008] [Revised: 07/23/2008] [Accepted: 08/18/2008] [Indexed: 01/19/2023] Open
Abstract
INTRODUCTION Hypertrophic cardiomyopathy (HCM) is a heterogeneous disorder of the cardiac sarcomere, resulting in myocyte hypertrophy and disarray, interstitial fibrosis, and cardiac dysfunction. Our aim was to determine whether the amount of fibrosis in HCM correlates with echocardiographic measures of diastolic dysfunction, presence of HCM-susceptibility mutations, or polymorphisms in the renin-angiotensin-aldosterone system (RAAS). METHODS Surgical specimens from patients with obstructive HCM undergoing septal myectomy at the Mayo Clinic (2001-2004) were examined and compared with autopsy-derived tissues from age- and sex-matched normal controls. Digital image analysis was used to quantitate the fibrosis in representative microscopic sections. Genotyping was performed for myofilament-HCM using polymerase chain reaction, high-performance liquid chromatography, and direct DNA sequencing. RAAS polymorphism status was similarly established. RESULTS The study included 59 HCM cases and 44 controls. Patients with HCM exhibited more fibrosis (mean 17%, range 3-45%) than controls (mean 8%, range 3-17%) (P<.0001). A significant relationship existed between amount of fibrosis and maximum wall thickness (P=.02), left ventricular ejection fraction (P=.02), and peak early/late diastolic mitral annulus velocity (E/A ratio) (P=.002). Although there was no association between amount of fibrosis and myofilament-HCM genotype status or polymorphisms in the RAAS cascade, there was a trend toward more fibrosis in patients with > or =1 C-encoding allele in CYP11B2-encoded aldosterone synthase. CONCLUSIONS Patients with HCM undergoing septal myectomy had significantly more myocardial interstitial fibrosis than controls. The amount of fibrosis in HCM patients correlated with degree of septal hypertrophy and left ventricular systolic and diastolic function. Notably, neither mutations in cardiac myofilament proteins or polymorphisms in RAAS exhibited strong associations with severity of myocardial fibrosis.
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166
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Nishii K, Morimoto S, Minakami R, Miyano Y, Hashizume K, Ohta M, Zhan DY, Lu QW, Shibata Y. Targeted disruption of the cardiac troponin T gene causes sarcomere disassembly and defects in heartbeat within the early mouse embryo. Dev Biol 2008; 322:65-73. [DOI: 10.1016/j.ydbio.2008.07.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Revised: 07/02/2008] [Accepted: 07/03/2008] [Indexed: 12/17/2022]
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167
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Abstract
Cardiomyopathy is defined as a cardiac disease caused by functional abnormality of cardiac muscle, and the etiology of the functional abnormality includes both extrinsic and intrinsic factors. Cardiomyopathy caused by the intrinsic factors is defined as idiopathic or primary cardiomyopathy, and there are several clinical phenotypes, including hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM). The major intrinsic factor is gene mutations, and linkage studies, as well as candidate gene approaches, have deciphered multiple disease genes for hereditary primary cardiomyopathy. Of note is that mutations in the same disease gene can be found in different clinical phenotypes of cardiomyopathy. Functional analyses of disease-related mutations have revealed that characteristic functional alterations are associated with the clinical phenotypes, such that increased and decreased Ca(2+) sensitivity because of sarcomere mutations are associated with HCM and DCM, respectively. In addition, recent data have suggested that mutations in the Z-disc components found in HCM and DCM may result in increased and decreased stiffness of the sarcomere (ie, stiff sarcomere and loose sarcomere, respectively). More recently, mutations in the components of the I region can be found in hereditary cardiomyopathy, further complicating the etiology of primary cardiomyopathy.
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Affiliation(s)
- Akinori Kimura
- Department of Molecular Pathogenesis, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan.
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168
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Taghli-Lamallem O, Bodmer R, Chamberlain JS, Cammarato A. Genetics and pathogenic mechanisms of cardiomyopathies in the Drosophila model. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.ddmod.2009.02.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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169
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Milewicz DM, Guo DC, Tran-Fadulu V, Lafont AL, Papke CL, Inamoto S, Kwartler CS, Pannu H. Genetic Basis of Thoracic Aortic Aneurysms and Dissections: Focus on Smooth Muscle Cell Contractile Dysfunction. Annu Rev Genomics Hum Genet 2008; 9:283-302. [DOI: 10.1146/annurev.genom.8.080706.092303] [Citation(s) in RCA: 315] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dianna M. Milewicz
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
| | - Dong-Chuan Guo
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
| | - Van Tran-Fadulu
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
| | - Andrea L. Lafont
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
| | - Christina L. Papke
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
| | - Sakiko Inamoto
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
| | - Carrie S. Kwartler
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
| | - Hariyadarshi Pannu
- Department of Internal Medicine, University of Texas, Houston, Texas 77030;
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170
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Tsoutsman T, Bagnall RD, Semsarian C. Impact of multiple gene mutations in determining the severity of cardiomyopathy and heart failure. Clin Exp Pharmacol Physiol 2008; 35:1349-57. [PMID: 18761664 DOI: 10.1111/j.1440-1681.2008.05037.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. Familial hypertrophic cardiomyopathy (FHC) is a primary cardiac disorder characterized by myocardial hypertrophy that demonstrates substantial diversity in both genetic causes and clinical manifestations. 2. Clinical heterogeneity can be explained by the causative gene (at least 13 have been identified to date), the position of the amino acid residue affected by a mutation within the protein (over 450 mutations have been reported to date) and modifying genetic and environmental factors. 3. Multiple mutations are found in up to 5% of human FHC cases, who typically present with a more severe phenotype compared with single-mutation carriers (i.e. earlier onset of disease, greater left ventricular hypertrophy and a higher incidence of sudden cardiac death events). 4. Multiple mutations usually involve MYH7, MYBPC3 and, to a lesser extent, TNNI2, reflecting the higher contribution of mutations in these genes to FHC. 5. Multiple-mutation mouse models appear to mimic the human multiple-mutation phenotype and, thus, will help improve our understanding of disease pathogenesis. The models provide a tool for future studies of disease mechanisms and signalling pathways in FHC and its sequelae (i.e. heart failure and sudden death), thereby allowing identification of novel targets for potential therapies and disease prevention strategies.
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Affiliation(s)
- Tatiana Tsoutsman
- Agnes Ginges Centre for Molecular Cardiology, Centenary Institute, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
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171
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Sadayappan S, Robbins J. The death of transcriptional chauvinism in the control and regulation of cardiac contractility. Ann N Y Acad Sci 2008; 1123:1-9. [PMID: 18375572 DOI: 10.1196/annals.1420.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
In the last 25 years we have witnessed the triumph of the genome. There are now well over 200 complete genome sequences. The application of modern solid state technologies to genomic sequencing promises affordable personalized sequences for the individual in the very near future. With this explosion in DNA sequence data, the focus in the immediate past has been on the primary DNA sequence, the cis-trans interactions that underlie controlled transcription, cataloging the transcriptome, and applying rudimentary systems analysis to those data sets in an attempt to assign molecular signatures to normal and abnormal physiological states. However, it is becoming clear that the post-transcriptional processes, which operate at the levels of RNA stability and selection for translational initiation, as well as the post-translational processes of protein stability, trafficking, and secondary modifications, such as phosphorylation, all play key roles in the homeostasis of the contractile apparatus and its overall function. Defining the interplay of these processes, in concert with the signaling pathways that allow transcription, translation, and post-translational processes to be quickly modified in response to events outside of the cardiomyocyte are leading to an understanding of the spatial and temporal requirements for each of these processes in controlling cardiac output. In order to confirm the importance of post-translational modification in controlling cardiac contractility in vivo, we examined the role that post-translational modification of an important component of the cardiac contractile apparatus, myosin binding protein C (MyBP-C), plays in the normal and diseased heart by creating transgenic mice in which the effects of chronic cardiac MyBP-C phosphorylation and dephosphorylation could be determined.
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Affiliation(s)
- Sakthivel Sadayappan
- Cincinnati Children's Hospital, University of Cincinnati, Cincinnati, OH 45229-3039, USA
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172
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Yamada S, Nelson TJ, Crespo-Diaz RJ, Perez-Terzic C, Liu XK, Miki T, Seino S, Behfar A, Terzic A. Embryonic stem cell therapy of heart failure in genetic cardiomyopathy. Stem Cells 2008; 26:2644-53. [PMID: 18669912 DOI: 10.1634/stemcells.2008-0187] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pathogenic causes underlying nonischemic cardiomyopathies are increasingly being resolved, yet repair therapies for these commonly heritable forms of heart failure are lacking. A case in point is human dilated cardiomyopathy 10 (CMD10; Online Mendelian Inheritance in Man #608569), a progressive organ dysfunction syndrome refractory to conventional therapies and linked to mutations in cardiac ATP-sensitive K(+) (K(ATP)) channel subunits. Embryonic stem cell therapy demonstrates benefit in ischemic heart disease, but the reparative capacity of this allogeneic regenerative cell source has not been tested in inherited cardiomyopathy. Here, in a Kir6.2-knockout model lacking functional K(ATP) channels, we recapitulated under the imposed stress of pressure overload the gene-environment substrate of CMD10. Salient features of the human malignant heart failure phenotype were reproduced, including compromised contractility, ventricular dilatation, and poor survival. Embryonic stem cells were delivered through the epicardial route into the left ventricular wall of cardiomyopathic stressed Kir6.2-null mutants. At 1 month of therapy, transplantation of 200,000 cells per heart achieved teratoma-free reversal of systolic dysfunction and electrical synchronization and halted maladaptive remodeling, thereby preventing end-stage organ failure. Tracked using the lacZ reporter transgene, stem cells engrafted into host heart. Beyond formation of cardiac tissue positive for Kir6.2, transplantation induced cell cycle activation and halved fibrotic zones, normalizing sarcomeric and gap junction organization within remuscularized hearts. Improved systemic function induced by stem cell therapy translated into increased stamina, absence of anasarca, and benefit to overall survivorship. Embryonic stem cells thus achieve functional repair in nonischemic genetic cardiomyopathy, expanding indications to the therapy of heritable heart failure. Disclosure of potential conflicts of interest is found at the end of this article.
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Affiliation(s)
- Satsuki Yamada
- Department of Medicine, Division of Cardiovascular Diseases, Marriott Heart Disease Research Program, Mayo Clinic, Rochester, Minnesota, USA. 55905, USA.
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Menon SC, Michels VV, Pellikka PA, Ballew JD, Karst ML, Herron KJ, Nelson SM, Rodeheffer RJ, Olson TM. Cardiac troponin T mutation in familial cardiomyopathy with variable remodeling and restrictive physiology. Clin Genet 2008; 74:445-54. [PMID: 18651846 DOI: 10.1111/j.1399-0004.2008.01062.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We identified a unique family with autosomal dominant heart disease variably expressed as restrictive cardiomyopathy (RCM), hypertrophic cardiomyopathy (HCM), and dilated cardiomyopathy (DCM), and sought to identify the molecular defect that triggered divergent remodeling pathways. Polymorphic DNA markers for nine sarcomeric genes for DCM and/or HCM were tested for segregation with disease. Linkage to eight genes was excluded, but a cardiac troponin T (TNNT2) marker cosegregated with the disease phenotype. Sequencing of TNNT2 identified a heterozygous missense mutation resulting in an I79N substitution, inherited by all nine affected family members but by none of the six unaffected relatives. Mutation carriers were diagnosed with RCM (n = 2), non-obstructive HCM (n = 3), DCM (n = 2), mixed cardiomyopathy (n = 1), and mild concentric left ventricular hypertrophy (n = 1). Endomyocardial biopsy in the proband revealed non-specific fibrosis, myocyte hypertrophy, and no myofibrillar disarray. Restrictive Doppler filling patterns, atrial enlargement, and pulmonary hypertension were observed among family members regardless of cardiomyopathy subtype. Mutation of a sarcomeric protein gene can cause RCM, HCM, and DCM within the same family, underscoring the necessity of comprehensive morphological and physiological cardiac assessment in familial cardiomyopathy screening.
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Affiliation(s)
- S C Menon
- Department of Pediatric and Adolescent Medicine, Division of Cardiology, College of Medicine, Mayo Clinic, Rochester, MN 55905, USA
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174
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Ahmad F, Banerjee SK, Lage ML, Huang XN, Smith SH, Saba S, Rager J, Conner DA, Janczewski AM, Tobita K, Tinney JP, Moskowitz IP, Perez-Atayde AR, Keller BB, Mathier MA, Shroff SG, Seidman CE, Seidman JG. The role of cardiac troponin T quantity and function in cardiac development and dilated cardiomyopathy. PLoS One 2008; 3:e2642. [PMID: 18612386 PMCID: PMC2441440 DOI: 10.1371/journal.pone.0002642] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Accepted: 05/31/2008] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Hypertrophic (HCM) and dilated (DCM) cardiomyopathies result from sarcomeric protein mutations, including cardiac troponin T (cTnT, TNNT2). We determined whether TNNT2 mutations cause cardiomyopathies by altering cTnT function or quantity; whether the severity of DCM is related to the ratio of mutant to wildtype cTnT; whether Ca(2+) desensitization occurs in DCM; and whether absence of cTnT impairs early embryonic cardiogenesis. METHODS AND FINDINGS We ablated Tnnt2 to produce heterozygous Tnnt2(+/-) mice, and crossbreeding produced homozygous null Tnnt2(-/-) embryos. We also generated transgenic mice overexpressing wildtype (TG(WT)) or DCM mutant (TG(K210Delta)) Tnnt2. Crossbreeding produced mice lacking one allele of Tnnt2, but carrying wildtype (Tnnt2(+/-)/TG(WT)) or mutant (Tnnt2(+/-)/TG(K210Delta)) transgenes. Tnnt2(+/-) mice relative to wildtype had significantly reduced transcript (0.82+/-0.06[SD] vs. 1.00+/-0.12 arbitrary units; p = 0.025), but not protein (1.01+/-0.20 vs. 1.00+/-0.13 arbitrary units; p = 0.44). Tnnt2(+/-) mice had normal hearts (histology, mass, left ventricular end diastolic diameter [LVEDD], fractional shortening [FS]). Moreover, whereas Tnnt2(+/-)/TG(K210Delta) mice had severe DCM, TG(K210Delta) mice had only mild DCM (FS 18+/-4 vs. 29+/-7%; p<0.01). The difference in severity of DCM may be attributable to a greater ratio of mutant to wildtype Tnnt2 transcript in Tnnt2(+/-)/TG(K210Delta) relative to TG(K210Delta) mice (2.42+/-0.08, p = 0.03). Tnnt2(+/-)/TG(K210Delta) muscle showed Ca(2+) desensitization (pCa(50) = 5.34+/-0.08 vs. 5.58+/-0.03 at sarcomere length 1.9 microm, p<0.01), but no difference in maximum force generation. Day 9.5 Tnnt2(-/-) embryos had normally looped hearts, but thin ventricular walls, large pericardial effusions, noncontractile hearts, and severely disorganized sarcomeres. CONCLUSIONS Absence of one Tnnt2 allele leads to a mild deficit in transcript but not protein, leading to a normal cardiac phenotype. DCM results from abnormal function of a mutant protein, which is associated with myocyte Ca(2+) desensitization. The severity of DCM depends on the ratio of mutant to wildtype Tnnt2 transcript. cTnT is essential for sarcomere formation, but normal embryonic heart looping occurs without contractile activity.
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Affiliation(s)
- Ferhaan Ahmad
- Cardiovascular Institute, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
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175
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Fokstuen S, Lyle R, Munoz A, Gehrig C, Lerch R, Perrot A, Osterziel KJ, Geier C, Beghetti M, Mach F, Sztajzel J, Sigwart U, Antonarakis SE, Blouin JL. A DNA resequencing array for pathogenic mutation detection in hypertrophic cardiomyopathy. Hum Mutat 2008; 29:879-85. [DOI: 10.1002/humu.20749] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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176
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Geier C, Gehmlich K, Ehler E, Hassfeld S, Perrot A, Hayess K, Cardim N, Wenzel K, Erdmann B, Krackhardt F, Posch MG, Bublak A, Nägele H, Scheffold T, Dietz R, Chien KR, Spuler S, Fürst DO, Nürnberg P, Özcelik C. Beyond the sarcomere: CSRP3 mutations cause hypertrophic cardiomyopathy. Hum Mol Genet 2008; 17:2753-65. [DOI: 10.1093/hmg/ddn160] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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177
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Werner P, Raducha MG, Prociuk U, Sleeper MM, Van Winkle TJ, Henthorn PS. A novel locus for dilated cardiomyopathy maps to canine chromosome 8. Genomics 2008; 91:517-21. [PMID: 18442891 DOI: 10.1016/j.ygeno.2008.03.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2008] [Revised: 03/07/2008] [Accepted: 03/12/2008] [Indexed: 11/26/2022]
Abstract
Dilated cardiomyopathy (DCM), the most common form of cardiomyopathy, often leads to heart failure and sudden death. While a substantial proportion of DCMs are inherited, mutations responsible for the majority of DCMs remain unidentified. A genome-wide linkage study was performed to identify the locus responsible for an autosomal recessive inherited form of juvenile DCM (JDCM) in Portuguese water dogs using 16 families segregating the disease. Results link the JDCM locus to canine chromosome 8 with two-point and multipoint lod scores of 10.8 and 14, respectively. The locus maps to a 3.9-Mb region, with complete syntenic homology to human chromosome 14, that contains no genes or loci known to be involved in the development of any type of cardiomyopathy. This discovery of a DCM locus with a previously unknown etiology will provide a new gene to examine in human DCM patients and a model for testing therapeutic approaches for heart failure.
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Affiliation(s)
- Petra Werner
- Section of Medical Genetics, Department of Clinical Studies-Philadelphia, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104-6010, USA.
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178
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Kohler JJ, Hosseini SH, Lewis W. Mitochondrial DNA impairment in nucleoside reverse transcriptase inhibitor-associated cardiomyopathy. Chem Res Toxicol 2008; 21:990-6. [PMID: 18393452 DOI: 10.1021/tx8000219] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Acquired immune deficiency syndrome (AIDS) is a global epidemic that continues to escalate. Recent World Health Organization estimates include over 33 million people currently diagnosed with HIV/AIDS. Another 20 million HIV-infected individuals died over the past quarter century. Antiretrovirals are effective treatments that changed the outcome of HIV infection from a fatal disease to a chronic illness. Cardiomyopathy (CM) is a bona fide component of HIV/AIDS with occurrence that is higher in HIV positive individuals. CM may result from individual or combined effects of HIV, immune reactions, or toxicities of prolonged antiretrovirals. Nucleoside reverse transcriptase inhibitors (NRTIs) are the cornerstone of antiretroviral therapy. Despite pharmacological benefits of NRTIs, NRTI side effects include increased risk for CM. Clinical observations and in vitro and in vivo studies support various mechanisms of CM. This perspective highlights some of the hypotheses and focuses on mitochondrial-associated pathways of NRTI- related CM.
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Affiliation(s)
- James J Kohler
- Department of Pathology, Emory University, 101 Woodruff Circle, WMB, Atlanta, Georgia 30322, USA
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179
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180
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Ohtsuki I, Morimoto S. Troponin: Regulatory function and disorders. Biochem Biophys Res Commun 2008; 369:62-73. [DOI: 10.1016/j.bbrc.2007.11.187] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2007] [Accepted: 11/22/2007] [Indexed: 11/29/2022]
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181
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Liang B, Chung F, Qu Y, Pavlov D, Gillis TE, Tikunova SB, Davis JP, Tibbits GF. Familial hypertrophic cardiomyopathy-related cardiac troponin C mutation L29Q affects Ca2+ binding and myofilament contractility. Physiol Genomics 2008; 33:257-66. [PMID: 18285522 DOI: 10.1152/physiolgenomics.00154.2007] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cardiac troponin C (cTnC) mutation, L29Q, has been found in a patient with familial hypertrophic cardiomyopathy. We previously showed that L29, together with neighboring residues, Asp2, Val28, and Gly30, plays an important role in determining the Ca(2+) affinity of site II, the regulatory site of mammalian cardiac troponin C (McTnC). Here we report on the Ca(2+) binding characteristics of L29Q McTnC and D2N/V28I/L29Q/G30D McTnC (NIQD) utilizing the Phe(27) --> Trp (F27W) substitution, allowing one to monitor Ca(2+) binding and release. We also studied the effect of these mutants on Ca(2+) activation of force generation in single mouse cardiac myocytes using cTnC replacement, together with sarcomere length (SL) dependence. The Ca(2+)-binding affinity of site II of L29Q McTnC(F27W) and NIQD McTnC(F27W) was approximately 1.3- and approximately 1.9-fold higher, respectively, than that of McTnC(F27W). The Ca(2+) disassociation rate from site II of L29Q McTnC(F27W) and NIQD McTnC(F27W) was not significantly different than that of control (McTnC(F27W)). However, the rate of Ca(2+) binding to site II was higher in L29Q McTnC(F27W) and NIQD McTnC(F27W) relative to control (approximately 1.5-fold and approximately 2.0-fold respectively). The Ca(2+) sensitivity of force generation was significantly higher in myocytes reconstituted with L29Q McTnC (approximately 1.4-fold) and NIQD McTnC (approximately 2-fold) compared with those reconstituted with McTnC. Interestingly, the change in Ca(2+) sensitivity of force generation in response to an SL change (1.9, 2.1, and 2.3 mum) was significantly reduced in myocytes containing L29Q McTnC or NIQD McTnC. These results demonstrate that the L29Q mutation enhances the Ca(2+)-binding characteristics of cTnC and that when incorporated into cardiac myocytes, this mutant alters myocyte contractility.
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Affiliation(s)
- Bo Liang
- Cardiac Membrane Research Laboratory, Kinesiology, Simon Fraser University, Burnaby, Canada
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182
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A novel β-myosin heavy chain gene mutation, p.Met531Arg, identified in isolated left ventricular non-compaction in humans, results in left ventricular hypertrophy that progresses to dilation in a mouse model. Clin Sci (Lond) 2008; 114:431-40. [DOI: 10.1042/cs20070179] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutations in the βMHC (β-myosin heavy chain), a sarcomeric protein are responsible for hypertrophic and dilated cardiomyopathy. However, the mechanisms whereby distinct mutations in the βMHC gene cause two kinds of cardiomyopathy are still unclear. In the present study we report a novel βMHC mutation found in a patient with isolated LVNC [LV (left ventricular) non-compaction] and the phenotype of a mouse mutant model carrying the same mutation. To find the mutation responsible, we searched for genomic mutations in 99 unrelated probands with dilated cardiomyopathy and five probands with isolated LVNC, and identified a p.Met531Arg mutation in βMHC in a 13-year-old girl with isolated LVNC. Next, we generated six lines of transgenic mice carrying a p.Met532Arg mutant αMHC gene, which was identical with the p.Met531Arg mutation in the human βMHC. Among these, two lines with strong expression of the mutant αMHC gene were chosen for further studies. Although they did not exhibit the features characteristic of LVNC, approx. 50% and 70% of transgenic mice in each line displayed LVH (LV hypertrophy) by 2–3 months of age. Furthermore, LVD (LV dilation) developed in approx. 25% of transgenic mice by 18 months of age, demonstrating biphasic changes in LV wall thickness. The present study supports the idea that common mechanisms may be involved in LVH and LVD. The novel mouse model generated can provide important information for the understanding of the pathological processes and aetiology of cardiac dilation in humans.
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183
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Targeted deletion of Dicer in the heart leads to dilated cardiomyopathy and heart failure. Proc Natl Acad Sci U S A 2008; 105:2111-6. [PMID: 18256189 DOI: 10.1073/pnas.0710228105] [Citation(s) in RCA: 435] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Cardiovascular disease is the leading cause of human morbidity and mortality. Dilated cardiomyopathy (DCM) is the most common form of cardiomyopathy associated with heart failure. Here, we report that cardiac-specific knockout of Dicer, a gene encoding a RNase III endonuclease essential for microRNA (miRNA) processing, leads to rapidly progressive DCM, heart failure, and postnatal lethality. Dicer mutant mice show misexpression of cardiac contractile proteins and profound sarcomere disarray. Functional analyses indicate significantly reduced heart rates and decreased fractional shortening of Dicer mutant hearts. Consistent with the role of Dicer in animal hearts, Dicer expression was decreased in end-stage human DCM and failing hearts and, most importantly, a significant increase of Dicer expression was observed in those hearts after left ventricle assist devices were inserted to improve cardiac function. Together, our studies demonstrate essential roles for Dicer in cardiac contraction and indicate that miRNAs play critical roles in normal cardiac function and under pathological conditions.
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184
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Cammarato A, Dambacher CM, Knowles AF, Kronert WA, Bodmer R, Ocorr K, Bernstein SI. Myosin transducer mutations differentially affect motor function, myofibril structure, and the performance of skeletal and cardiac muscles. Mol Biol Cell 2008; 19:553-62. [PMID: 18045988 PMCID: PMC2230588 DOI: 10.1091/mbc.e07-09-0890] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2007] [Revised: 11/06/2007] [Accepted: 11/16/2007] [Indexed: 12/12/2022] Open
Abstract
Striated muscle myosin is a multidomain ATP-dependent molecular motor. Alterations to various domains affect the chemomechanical properties of the motor, and they are associated with skeletal and cardiac myopathies. The myosin transducer domain is located near the nucleotide-binding site. Here, we helped define the role of the transducer by using an integrative approach to study how Drosophila melanogaster transducer mutations D45 and Mhc(5) affect myosin function and skeletal and cardiac muscle structure and performance. We found D45 (A261T) myosin has depressed ATPase activity and in vitro actin motility, whereas Mhc(5) (G200D) myosin has these properties enhanced. Depressed D45 myosin activity protects against age-associated dysfunction in metabolically demanding skeletal muscles. In contrast, enhanced Mhc(5) myosin function allows normal skeletal myofibril assembly, but it induces degradation of the myofibrillar apparatus, probably as a result of contractile disinhibition. Analysis of beating hearts demonstrates depressed motor function evokes a dilatory response, similar to that seen with vertebrate dilated cardiomyopathy myosin mutations, and it disrupts contractile rhythmicity. Enhanced myosin performance generates a phenotype apparently analogous to that of human restrictive cardiomyopathy, possibly indicating myosin-based origins for the disease. The D45 and Mhc(5) mutations illustrate the transducer's role in influencing the chemomechanical properties of myosin and produce unique pathologies in distinct muscles. Our data suggest Drosophila is a valuable system for identifying and modeling mutations analogous to those associated with specific human muscle disorders.
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Affiliation(s)
- Anthony Cammarato
- *Department of Biology and Heart Institute, San Diego State University, San Diego, CA 92182-4614
- Development and Aging Program, Burnham Institute for Medical Research, La Jolla, CA 92037; and
| | - Corey M. Dambacher
- *Department of Biology and Heart Institute, San Diego State University, San Diego, CA 92182-4614
| | - Aileen F. Knowles
- Department of Chemistry and Biochemistry, San Diego State University, San Diego, CA 92182-1030
| | - William A. Kronert
- *Department of Biology and Heart Institute, San Diego State University, San Diego, CA 92182-4614
| | - Rolf Bodmer
- Development and Aging Program, Burnham Institute for Medical Research, La Jolla, CA 92037; and
| | - Karen Ocorr
- Development and Aging Program, Burnham Institute for Medical Research, La Jolla, CA 92037; and
| | - Sanford I. Bernstein
- *Department of Biology and Heart Institute, San Diego State University, San Diego, CA 92182-4614
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187
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Mutations in smooth muscle α-actin (ACTA2) lead to thoracic aortic aneurysms and dissections. Nat Genet 2007; 39:1488-93. [DOI: 10.1038/ng.2007.6] [Citation(s) in RCA: 634] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Accepted: 09/04/2007] [Indexed: 11/09/2022]
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188
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Frank D, Kuhn C, Katus HA, Frey N. Role of the sarcomeric Z-disc in the pathogenesis of cardiomyopathy. Future Cardiol 2007; 3:611-22. [DOI: 10.2217/14796678.3.6.611] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The Z-disc has traditionally been viewed as a structure required to maintain sarcomeric function and integrity. More recently, the sarcomeric Z-disc has also emerged as a nodal point in cardiomyocyte signaling and mechanotransduction. This notion is not only supported by several transgenic animal models, but also by the identification of mutations in various Z-disc proteins, resulting in dilated or hypertrophic cardiomyopathy in patients. This review will thus focus on the role of the sarcomeric Z-disc and its associated proteins in the pathogenesis of cardiomyopathy.
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Affiliation(s)
- Derk Frank
- University of Heidelberg, Department of Internal Medicine III, Germany
| | - Christian Kuhn
- University of Heidelberg, Department of Internal Medicine III, Germany
| | - Hugo A Katus
- University of Heidelberg, Department of Internal Medicine III, Germany
| | - Norbert Frey
- Im Neuenheimer Feld 350, D-69120 Heidelberg, Germany
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189
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van Rooij E, Olson EN. MicroRNAs: powerful new regulators of heart disease and provocative therapeutic targets. J Clin Invest 2007; 117:2369-76. [PMID: 17786230 PMCID: PMC1952642 DOI: 10.1172/jci33099] [Citation(s) in RCA: 412] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
MicroRNAs act as negative regulators of gene expression by inhibiting the translation or promoting the degradation of target mRNAs. Recent studies have revealed key roles of microRNAs as regulators of the growth, development, function, and stress responsiveness of the heart, providing glimpses of undiscovered regulatory mechanisms and potential therapeutic targets for the treatment of heart disease.
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Affiliation(s)
- Eva van Rooij
- Department of Molecular Biology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9148, USA
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190
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Auman HJ, Coleman H, Riley HE, Olale F, Tsai HJ, Yelon D. Functional modulation of cardiac form through regionally confined cell shape changes. PLoS Biol 2007; 5:e53. [PMID: 17311471 PMCID: PMC1802756 DOI: 10.1371/journal.pbio.0050053] [Citation(s) in RCA: 214] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2006] [Accepted: 12/18/2006] [Indexed: 11/30/2022] Open
Abstract
Developing organs acquire a specific three-dimensional form that ensures their normal function. Cardiac function, for example, depends upon properly shaped chambers that emerge from a primitive heart tube. The cellular mechanisms that control chamber shape are not yet understood. Here, we demonstrate that chamber morphology develops via changes in cell morphology, and we determine key regulatory influences on this process. Focusing on the development of the ventricular chamber in zebrafish, we show that cardiomyocyte cell shape changes underlie the formation of characteristic chamber curvatures. In particular, cardiomyocyte elongation occurs within a confined area that forms the ventricular outer curvature. Because cardiac contractility and blood flow begin before chambers emerge, cardiac function has the potential to influence chamber curvature formation. Employing zebrafish mutants with functional deficiencies, we find that blood flow and contractility independently regulate cell shape changes in the emerging ventricle. Reduction of circulation limits the extent of cardiomyocyte elongation; in contrast, disruption of sarcomere formation releases limitations on cardiomyocyte dimensions. Thus, the acquisition of normal cardiomyocyte morphology requires a balance between extrinsic and intrinsic physical forces. Together, these data establish regionally confined cell shape change as a cellular mechanism for chamber emergence and as a link in the relationship between form and function during organ morphogenesis. As organs develop, they acquire a characteristic shape; the factors governing this complex process, however, are not understood. Shape may be sculpted by cell movement, cell division, or changes in cell size and shape, all of which can be influenced by the local environment. Here we investigate heart formation to understand how organs develop. The heart appears as a simple tube early in development; later, the tube walls bulge outward to form the cardiac chambers. Using transgenic zebrafish in which we can watch individual cardiac cells, we found that cells change size and shape, enlarging and elongating to form the bulges in the heart tube and eventually the chambers. Since the heart is beating as it develops, we asked whether cardiac function influences cell shape. Using zebrafish mutants with functional defects, we found that both blood flow and cardiac contractility influence cardiac cell shape. We propose that a balance of the cell's internal forces (through contractility) with external forces (such as blood flow) is necessary to create the cell shapes that generate chamber curvatures. Disruption of this balance may underlie the aberrations observed in some types of heart disease. Cardiac function depends upon properly shaped heart chambers. Here the authors show that blood flow and contractility independently regulate cell shape changes in the emerging ventricle.
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Affiliation(s)
- Heidi J Auman
- Developmental Genetics Program and Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Hope Coleman
- Developmental Genetics Program and Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Heather E Riley
- Developmental Genetics Program and Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Felix Olale
- Developmental Genetics Program and Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, United States of America
| | - Huai-Jen Tsai
- Institute of Molecular and Cell Biology, College of Life Science, National Taiwan University, Taipei, Taiwan
| | - Deborah Yelon
- Developmental Genetics Program and Department of Cell Biology, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York, United States of America
- * To whom correspondence should be addressed. E-mail:
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191
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Mayosi BM. Contemporary trends in the epidemiology and management of cardiomyopathy and pericarditis in sub-Saharan Africa. Heart 2007; 93:1176-83. [PMID: 17890693 PMCID: PMC2000928 DOI: 10.1136/hrt.2007.127746] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/24/2007] [Indexed: 11/04/2022] Open
Abstract
Heart failure in sub-Saharan Africans is mainly due to non-ischaemic causes, such as hypertension, rheumatic heart disease, cardiomyopathy and pericarditis. The two endemic diseases that are major contributors to the clinical syndrome of heart failure in Africa are cardiomyopathy and pericarditis. The major forms of endemic cardiomyopathy are idiopathic dilated cardiomyopathy, peripartum cardiomyopathy and endomyocardial fibrosis. Endomyocardial fibrosis, which affects children, has the worst prognosis. Other cardiomyopathies have similar epidemiological characteristics to those of other populations in the world. HIV infection is associated with occurrence of HIV-associated cardiomyopathy in patients with advanced immunosuppression, and the rise in the incidence of tuberculous pericarditis. HIV-associated tuberculous pericarditis is characterised by larger pericardial effusion, a greater frequency of myopericarditis, and a higher mortality than in people without AIDS. Population-based studies on the epidemiology of heart failure, cardiomyopathy and pericarditis in Africans, and studies of new interventions to reduce mortality, particularly in endomyocardial fibrosis and tuberculous pericarditis, are needed.
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Affiliation(s)
- Bongani M Mayosi
- Department of Medicine, J Floor Old Main Building, Groote Schuur Hospital, Observatory 7925, Cape Town, South Africa.
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192
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Larson MG, Atwood LD, Benjamin EJ, Cupples LA, D'Agostino RB, Fox CS, Govindaraju DR, Guo CY, Heard-Costa NL, Hwang SJ, Murabito JM, Newton-Cheh C, O'Donnell CJ, Seshadri S, Vasan RS, Wang TJ, Wolf PA, Levy D. Framingham Heart Study 100K project: genome-wide associations for cardiovascular disease outcomes. BMC MEDICAL GENETICS 2007; 8 Suppl 1:S5. [PMID: 17903304 PMCID: PMC1995607 DOI: 10.1186/1471-2350-8-s1-s5] [Citation(s) in RCA: 141] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
BACKGROUND Cardiovascular disease (CVD) and its most common manifestations--including coronary heart disease (CHD), stroke, heart failure (HF), and atrial fibrillation (AF)--are major causes of morbidity and mortality. In many industrialized countries, cardiovascular disease (CVD) claims more lives each year than any other disease. Heart disease and stroke are the first and third leading causes of death in the United States. Prior investigations have reported several single gene variants associated with CHD, stroke, HF, and AF. We report a community-based genome-wide association study of major CVD outcomes. METHODS In 1345 Framingham Heart Study participants from the largest 310 pedigrees (54% women, mean age 33 years at entry), we analyzed associations of 70,987 qualifying SNPs (Affymetrix 100K GeneChip) to four major CVD outcomes: major atherosclerotic CVD (n = 142; myocardial infarction, stroke, CHD death), major CHD (n = 118; myocardial infarction, CHD death), AF (n = 151), and HF (n = 73). Participants free of the condition at entry were included in proportional hazards models. We analyzed model-based deviance residuals using generalized estimating equations to test associations between SNP genotypes and traits in additive genetic models restricted to autosomal SNPs with minor allele frequency > or =0.10, genotype call rate > or =0.80, and Hardy-Weinberg equilibrium p-value > or = 0.001. RESULTS Six associations yielded p < 10(-5). The lowest p-values for each CVD trait were as follows: major CVD, rs499818, p = 6.6 x 10(-6); major CHD, rs2549513, p = 9.7 x 10(-6); AF, rs958546, p = 4.8 x 10(-6); HF: rs740363, p = 8.8 x 10(-6). Of note, we found associations of a 13 Kb region on chromosome 9p21 with major CVD (p 1.7-1.9 x 10(-5)) and major CHD (p 2.5-3.5 x 10(-4)) that confirm associations with CHD in two recently reported genome-wide association studies. Also, rs10501920 in CNTN5 was associated with AF (p = 9.4 x 10(-6)) and HF (p = 1.2 x 10(-4)). Complete results for these phenotypes can be found at the dbgap website http://www.ncbi.nlm.nih.gov/projects/gap/cgi-bin/study.cgi?id=phs000007 webcite. CONCLUSION No association attained genome-wide significance, but several intriguing findings emerged. Notably, we replicated associations of chromosome 9p21 with major CVD. Additional studies are needed to validate these results. Finding genetic variants associated with CVD may point to novel disease pathways and identify potential targeted preventive therapies.
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Affiliation(s)
- Martin G Larson
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Department of Mathematics and Statistics, Boston University, Boston, MA, USA
| | - Larry D Atwood
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
| | - Emelia J Benjamin
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - L Adrienne Cupples
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Department of Biostatistics, Boston University School of Public Health, Boston, MA, USA
| | - Ralph B D'Agostino
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Department of Mathematics and Statistics, Boston University, Boston, MA, USA
| | - Caroline S Fox
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
| | - Diddahally R Govindaraju
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
| | - Chao-Yu Guo
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
| | - Nancy L Heard-Costa
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
| | - Shih-Jen Hwang
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
| | - Joanne M Murabito
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Section of General Internal Medicine, Boston University School of Medicine, Boston, MA, USA
| | - Christopher Newton-Cheh
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard and MIT, Cambridge, MA, USA
| | - Christopher J O'Donnell
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Sudha Seshadri
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
| | - Ramachandran S Vasan
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Thomas J Wang
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Cardiology Division, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Philip A Wolf
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
- Boston University School of Medicine, Boston, MA, USA
| | - Daniel Levy
- The National Heart, Lung, and Blood Institute's Framingham Heart Study, Framingham, MA, USA
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194
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Ruan H, Mitchell S, Vainoriene M, Lou Q, Xie LH, Ren S, Goldhaber JI, Wang Y. Giα1-Mediated Cardiac Electrophysiological Remodeling and Arrhythmia in Hypertrophic Cardiomyopathy. Circulation 2007; 116:596-605. [PMID: 17646583 DOI: 10.1161/circulationaha.106.682773] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Cardiac hypertrophy is a major risk factor for arrhythmias and sudden cardiac death. However, the underlying signaling mechanisms involved in the induction of arrhythmia and electrophysiological remodeling in cardiac hypertrophy are unclear. METHODS AND RESULTS Using an inducible gene-switch approach, we achieved tissue-specific and temporally regulated induction of a well-established hypertrophic pathway, the Ras-Raf-mitogen-activated protein kinases pathway, in adult mouse heart. On Ras activation, the transgenic animal developed ventricular hypertrophy and arrhythmias. The development of ventricular arrhythmias was temporally correlated with electrophysiological remodeling in isolated ventricular myocytes, including action potential prolongation, increased sodium-calcium exchanger activity, reduced outward potassium currents, sarcoplasmic reticulum Ca2+ defects, and loss of protein kinase A-dependent phospholamban phosphorylation. From genome-wide expression profiling, we discovered a selective induction of G alpha inhibiting subunit 1 (Gi alpha1) expression in the Ras transgenic heart. Treatment of transgenic animals with the Gi/o inhibitor pertussis toxin normalized the phospholamban phosphorylation by protein kinase A, reversed the action potential prolongation, and significantly reduced the frequency of cardiac arrhythmias in Ras transgenic animals. CONCLUSIONS These data suggest that selective induction of G alpha inhibiting subunit 1 expression and activity is a novel downstream event in hypertrophic signaling that may be a critical factor leading to cellular electrophysiological remodeling and cardiac arrhythmias in hypertrophic cardiomyopathy.
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MESH Headings
- Animals
- Arrhythmias, Cardiac/genetics
- Arrhythmias, Cardiac/metabolism
- Arrhythmias, Cardiac/physiopathology
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/metabolism
- Cardiomyopathy, Hypertrophic/physiopathology
- Electrocardiography/methods
- Electrophysiology
- GTP-Binding Protein alpha Subunits, Gi-Go/biosynthesis
- GTP-Binding Protein alpha Subunits, Gi-Go/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Ventricular Remodeling/genetics
- Ventricular Remodeling/physiology
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Affiliation(s)
- Hongmei Ruan
- Department of Anesthesiology, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
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195
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Pannu H, Tran-Fadulu V, Papke CL, Scherer S, Liu Y, Presley C, Guo D, Estrera AL, Safi HJ, Brasier AR, Vick GW, Marian A, Raman C, Buja LM, Milewicz DM. MYH11 mutations result in a distinct vascular pathology driven by insulin-like growth factor 1 and angiotensin II. Hum Mol Genet 2007; 16:2453-62. [PMID: 17666408 PMCID: PMC2905218 DOI: 10.1093/hmg/ddm201] [Citation(s) in RCA: 210] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Non-syndromic thoracic aortic aneurysms and dissections (TAADs) are inherited in an autosomal dominant manner in approximately 20% of cases. Familial TAAD is genetically heterogeneous and four loci have been mapped for this disease to date, including a locus at 16p for TAAD associated with patent ductus arteriosus (PDA). The defective gene at the 16p locus has recently been identified as the smooth muscle cell (SMC)-specific myosin heavy chain gene (MYH11). On sequencing MYH11 in 93 families with TAAD alone and three families with TAAD/PDA, we identified novel mutations in two families with TAAD/PDA, but none in families with TAAD alone. Histopathological analysis of aortic sections from two individuals with MYH11 mutations revealed SMC disarray and focal hyperplasia of SMCs in the aortic media. SMC hyperplasia leading to significant lumen narrowing in some of the vessels of the adventitia was also observed. Insulin-like growth factor-1 (IGF-1) was upregulated in mutant aortas as well as explanted SMCs, but no increase in transforming growth factor-beta expression or downstream targets was observed. Enhanced expression of angiotensin-converting enzyme and markers of Angiotensin II (Ang II) vascular inflammation (macrophage inflammatory protein-1alpha and beta) were also found. These data suggest that MYH11 mutations are likely to be specific to the phenotype of TAAD/PDA and result in a distinct aortic and occlusive vascular pathology potentially driven by IGF-1 and Ang II.
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Affiliation(s)
- Hariyadarshi Pannu
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Van Tran-Fadulu
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Christina L. Papke
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Steve Scherer
- Human Genetics Center, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - Yaozhong Liu
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Caroline Presley
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Dongchuan Guo
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Anthony L. Estrera
- Department of Cardiothoracic and Vascular Surgery, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Hazim J. Safi
- Department of Cardiothoracic and Vascular Surgery, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Allan R. Brasier
- Department of Medicine, The University of Texas Medical Branch, Galveston, TX, USA
| | - G. Wesley Vick
- Lillie Frank Abercrombie Section of Pediatric Cardiology, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX, USA
| | - A.J. Marian
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - C.S. Raman
- Department of Biochemistry, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - L. Maximilian Buja
- Department of Pathology, The University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Dianna M. Milewicz
- Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, Houston, TX, USA
- To whom correspondence should be addressed at: Department of Internal Medicine and Institute of Molecular Medicine, The University of Texas Health Science Center at Houston, 6431 Fannin, MSB 6.100, Houston, TX 77030, USA. Tel: +1 7135006725; Fax: +1 7135000693.
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196
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Knöll R, Postel R, Wang J, Krätzner R, Hennecke G, Vacaru AM, Vakeel P, Schubert C, Murthy K, Rana BK, Kube D, Knöll G, Schäfer K, Hayashi T, Holm T, Kimura A, Schork N, Toliat MR, Nürnberg P, Schultheiss HP, Schaper W, Schaper J, Bos E, Den Hertog J, van Eeden FJM, Peters PJ, Hasenfuss G, Chien KR, Bakkers J. Laminin-alpha4 and integrin-linked kinase mutations cause human cardiomyopathy via simultaneous defects in cardiomyocytes and endothelial cells. Circulation 2007; 116:515-25. [PMID: 17646580 DOI: 10.1161/circulationaha.107.689984] [Citation(s) in RCA: 171] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Extracellular matrix proteins, such as laminins, and endothelial cells are known to influence cardiomyocyte performance; however, the underlying molecular mechanisms remain poorly understood. METHODS AND RESULTS We used a forward genetic screen in zebrafish to identify novel genes required for myocardial function and were able to identify the lost-contact (loc) mutant, which encodes a nonsense mutation in the integrin-linked kinase (ilk) gene. This loc/ilk mutant is associated with a severe defect in cardiomyocytes and endothelial cells that leads to severe myocardial dysfunction. Additional experiments revealed the epistatic regulation between laminin-alpha4 (Lama4), integrin, and Ilk, which led us to screen for mutations in the human ILK and LAMA4 genes in patients with severe dilated cardiomyopathy. We identified 2 novel amino acid residue-altering mutations (2828C>T [Pro943Leu] and 3217C>T [Arg1073X]) in the integrin-interacting domain of the LAMA4 gene and 1 mutation (785C>T [Ala262Val]) in the ILK gene. Biacore quantitative protein/protein interaction data, which have been used to determine the equilibrium dissociation constants, point to the loss of integrin-binding capacity in case of the Pro943Leu (Kd=5+/-3 micromol/L) and Arg1073X LAMA4 (Kd=1+/-0.2 micromol/L) mutants compared with the wild-type LAMA4 protein (Kd=440+/-20 nmol/L). Additional functional data point to the loss of endothelial cells in affected patients as a direct consequence of the mutant genes, which ultimately leads to heart failure. CONCLUSIONS This is the first report on mutations in the laminin, integrin, and ILK system in human cardiomyopathy, which has consequences for endothelial cells as well as for cardiomyocytes, thus providing a new genetic basis for dilated cardiomyopathy in humans.
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MESH Headings
- Adult
- Amino Acid Substitution
- Animals
- COS Cells
- Cardiomyopathy, Dilated/genetics
- Cardiomyopathy, Dilated/metabolism
- Cardiomyopathy, Dilated/pathology
- Cell Adhesion
- Chlorocebus aethiops
- Chromosome Mapping
- Codon, Nonsense
- DNA Mutational Analysis
- Embryo, Nonmammalian/pathology
- Endothelial Cells/pathology
- Epigenesis, Genetic
- Extracellular Matrix/metabolism
- Extracellular Matrix/pathology
- Female
- Heart/embryology
- Heart Failure/etiology
- Heart Failure/pathology
- Humans
- Integrins/metabolism
- Laminin/genetics
- Laminin/physiology
- Male
- Middle Aged
- Models, Molecular
- Mutation, Missense
- Myocardium/pathology
- Myocytes, Cardiac/pathology
- Oligonucleotides, Antisense/toxicity
- Pedigree
- Point Mutation
- Protein Binding
- Protein Conformation
- Protein Interaction Mapping
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/physiology
- Protein Structure, Tertiary
- Transfection
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish Proteins/genetics
- Zebrafish Proteins/physiology
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Affiliation(s)
- Ralph Knöll
- Institute of Molecular Medicine, University of California at San Diego, La Jolla, Calif, USA.
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197
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Kantarci S, Donahoe PK. Congenital diaphragmatic hernia (CDH) etiology as revealed by pathway genetics. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2007; 145C:217-26. [PMID: 17436295 DOI: 10.1002/ajmg.c.30132] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Congenital diaphragmatic hernia (CDH) is a common birth defect with high mortality and morbidity. Two hundred seventy CDH patients were ascertained, carefully phenotyped, and classified as isolated (diaphragm defects alone) or complex (with additional anomalies) cases. We established different strategies to reveal CDH-critical chromosome loci and genes in humans. Candidate genes for sequencing analyses were selected from CDH animal models, genetic intervals of recurrent chromosomal aberration in humans, such as 15q26.1-q26.2 or 1q41-q42.12, as well as genes in the retinoic acid and related pathways and those known to be involved in embryonic lung development. For instance, FOG2, GATA4, and COUP-TFII are all needed for both normal diaphragm and lung development and are likely all in the same genetic and molecular pathway. Linkage analysis was applied first in a large inbred family and then in four multiplex families with Donnai-Barrow syndrome (DBS) associated with CDH. 10K SNP chip and microsatellite markers revealed a DBS locus on chromosome 2q23.3-q31.1. We applied array-based comparative genomic hybridization (aCGH) techniques to over 30, mostly complex, CDH patients and found a de novo microdeletion in a patient with Fryns syndrome related to CDH. Fluorescence in situ hybridization (FISH) and multiplex ligation-dependent probe amplification (MLPA) techniques allowed us to further define the deletion interval. Our aim is to identify genetic intervals and, in those, to prioritize genes that might reveal molecular pathways, mutations in any step of which, might contribute to the same phenotype. More important, the elucidation of pathways may ultimately provide clues to treatment strategies.
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Affiliation(s)
- Sibel Kantarci
- Peadiatric Surgical Research Laboratories at Massachusetts General Hospital, Boston, MA 02114, USA
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198
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Distl O, Vollmar AC, Broschk C, Hamann H, Fox PR. Complex segregation analysis of dilated cardiomyopathy (DCM) in Irish wolfhounds. Heredity (Edinb) 2007; 99:460-5. [PMID: 17611491 DOI: 10.1038/sj.hdy.6801024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The objective of the present study was to analyse the mode of inheritance for dilated cardiomyopathy (DCM) in Irish wolfhounds using regressive logistic models by testing for mechanisms of genetic transmission. Insights from this spontaneous animal model should aid importantly in understanding basic pathogenic mechanisms with regard to genetics and molecular biology of DCM in humans. Moreover, a procedure for the simultaneous prediction of breeding values and the estimation of genotype probabilities for DCM is expected to markedly improve breeding programmes. Results of cardiovascular examinations of 1018 dogs carried out between 1987 and 2003 by one veterinarian were analysed. Data of 878 dogs from 531 litters in 147 different kennels were used for complex segregation analyses. Pedigree information was available for more than 15 generations. Male dogs were affected significantly more often by DCM than female dogs. The segregation analysis showed that among all other tested models a mixed monogenic-polygenic model including a sex-dependent allele effect best explained the segregation of affected animals in the pedigrees. A pure monogenic inheritance of DCM could be significantly rejected in favour of the major gene and most general model. The gene action of the major gene was significantly different between female and male dogs.
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Affiliation(s)
- O Distl
- Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Hannover, Germany.
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199
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Debold EP, Schmitt JP, Patlak JB, Beck SE, Moore JR, Seidman JG, Seidman C, Warshaw DM. Hypertrophic and dilated cardiomyopathy mutations differentially affect the molecular force generation of mouse α-cardiac myosin in the laser trap assay. Am J Physiol Heart Circ Physiol 2007; 293:H284-91. [PMID: 17351073 DOI: 10.1152/ajpheart.00128.2007] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Point mutations in cardiac myosin, the heart's molecular motor, produce distinct clinical phenotypes: hypertrophic (HCM) and dilated (DCM) cardiomyopathy. Do mutations alter myosin's molecular mechanics in a manner that is predictive of the clinical outcome? We have directly characterized the maximal force-generating capacity (Fmax) of two HCM (R403Q, R453C) and two DCM (S532P, F764L) mutant myosins isolated from homozygous mouse models using a novel load-clamped laser trap assay. Fmaxwas 50% (R403Q) and 80% (R453C) greater for the HCM mutants compared with the wild type, whereas Fmaxwas severely depressed for one of the DCM mutants (65% S532P). Although Fmaxwas normal for the F764L DCM mutant, its actin-activated ATPase activity and actin filament velocity ( Vactin) in a motility assay were significantly reduced (Schmitt JP, Debold EP, Ahmad F, Armstrong A, Frederico A, Conner DA, Mende U, Lohse MJ, Warshaw D, Seidman CE, Seidman JG. Proc Natl Acad Sci USA 103: 14525–14530, 2006.). These Fmaxdata combined with previous Vactinmeasurements suggest that HCM and DCM result from alterations to one or more of myosin's fundamental mechanical properties, with HCM-causing mutations leading to enhanced but DCM-causing mutations leading to depressed function. These mutation-specific changes in mechanical properties must initiate distinct signaling cascades that ultimately lead to the disparate phenotypic responses observed in HCM and DCM.
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Affiliation(s)
- Edward P Debold
- Deptartment of Molecular Physiology and Biophysics, College of Medicine, University of Vermont, 149 Beaumont Avenue, Burlington, VT 05405, USA
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200
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Xiao L, Zhao Q, Du Y, Yuan C, Solaro RJ, Buttrick PM. PKCepsilon increases phosphorylation of the cardiac myosin binding protein C at serine 302 both in vitro and in vivo. Biochemistry 2007; 46:7054-61. [PMID: 17503784 PMCID: PMC3969456 DOI: 10.1021/bi700467k] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cardiac myosin binding protein C (cMyBPC) phosphorylation is essential for normal cardiac function. Although PKC was reported to phosphorylate cMyBPC in vitro, the relevant PKC isoforms and functions of PKC-mediated cMyBPC phosphorylation are unknown. We recently reported that a transgenic mouse model with cardiac-specific overexpression of PKCepsilon (PKCepsilon TG) displayed enhanced sarcomeric protein phosphorylation and dilated cardiomyopathy. In the present study, we have investigated cMyBPC phosphorylation in PKCepsilon TG mice. Western blotting and two-dimensional gel electrophoresis demonstrated a significant increase in cMyBPC serine (Ser) phosphorylation in 12-month-old TG mice compared to wild type (WT). In vitro PKCepsilon treatment of myofibrils increased the level of cMyBPC Ser phosphorylation in WT mice to that in TG mice, whereas treatment of TG myofibrils with PKCepsilon showed only a minimal increase in cMyBPC Ser phosphorylation. Three peptide motifs of cMyBPC were identified as the potential PKCepsilon consensus sites including a 100% matched motif at Ser302 and two nearly matched motifs at Ser811 and Ser1203. We treated synthetic peptides corresponding to the sequences of these three motifs with PKCepsilon and determined phosphorylation by mass spectrometry and ELISA assay. PKCepsilon induced phosphorylation at the Ser302 site but not at the Ser811 or Ser1203 sites. A S302A point mutation in the Ser302 peptide abolished the PKCepsilon-dependent phosphorylation. Taken together, our data show that the Ser302 on mouse cMyBPC is a likely PKCepsilon phosphorylation site both in vivo and in vitro and may contribute to the dilated cardiomyopathy associated with increased PKCepsilon activity.
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Affiliation(s)
| | | | | | | | | | - Peter M. Buttrick
- Address correspondence to this author at the Division of Cardiology, University of Colorado Health Sciences Center, 4200 East Ninth, Ave., B130, Denver, CO 80262. Tel: (303) 315-5394. Fax: (303) 315-5082.
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