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Burkart V, Kowalski K, Aldag-Niebling D, Beck J, Frick DA, Holler T, Radocaj A, Piep B, Zeug A, Hilfiker-Kleiner D, dos Remedios CG, van der Velden J, Montag J, Kraft T. Transcriptional bursts and heterogeneity among cardiomyocytes in hypertrophic cardiomyopathy. Front Cardiovasc Med 2022; 9:987889. [PMID: 36082122 PMCID: PMC9445301 DOI: 10.3389/fcvm.2022.987889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/02/2022] [Indexed: 12/01/2022] Open
Abstract
Transcriptional bursting is a common expression mode for most genes where independent transcription of alleles leads to different ratios of allelic mRNA from cell to cell. Here we investigated burst-like transcription and its consequences in cardiac tissue from Hypertrophic Cardiomyopathy (HCM) patients with heterozygous mutations in the sarcomeric proteins cardiac myosin binding protein C (cMyBP-C, MYBPC3) and cardiac troponin I (cTnI, TNNI3). Using fluorescence in situ hybridization (RNA-FISH) we found that both, MYBPC3 and TNNI3 are transcribed burst-like. Along with that, we show unequal allelic ratios of TNNI3-mRNA among single cardiomyocytes and unequally distributed wildtype cMyBP-C protein across tissue sections from heterozygous HCM-patients. The mutations led to opposing functional alterations, namely increasing (cMyBP-Cc.927−2A>G) or decreasing (cTnIR145W) calcium sensitivity. Regardless, all patients revealed highly variable calcium-dependent force generation between individual cardiomyocytes, indicating contractile imbalance, which appears widespread in HCM-patients. Altogether, we provide strong evidence that burst-like transcription of sarcomeric genes can lead to an allelic mosaic among neighboring cardiomyocytes at mRNA and protein level. In HCM-patients, this presumably induces the observed contractile imbalance among individual cardiomyocytes and promotes HCM-development.
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Affiliation(s)
- Valentin Burkart
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
- Valentin Burkart
| | - Kathrin Kowalski
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - David Aldag-Niebling
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Julia Beck
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Dirk Alexander Frick
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Tim Holler
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Ante Radocaj
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Birgit Piep
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Andre Zeug
- Institute for Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | | | - Cristobal G. dos Remedios
- Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | | | - Judith Montag
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
- *Correspondence: Judith Montag
| | - Theresia Kraft
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
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2
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Berecz T, Yiu A, Vittay O, Orsolits B, Mioulane M, dos Remedios CG, Ketteler R, Merkely B, Apáti Á, Harding SE, Hellen N, Foldes G. Transcriptional co-activators YAP1-TAZ of Hippo signalling in doxorubicin-induced cardiomyopathy. ESC Heart Fail 2022; 9:224-235. [PMID: 34931757 PMCID: PMC8787991 DOI: 10.1002/ehf2.13756] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 11/02/2021] [Accepted: 11/24/2021] [Indexed: 11/07/2022] Open
Abstract
AIMS Hippo signalling is an evolutionarily conserved pathway that controls organ size by regulating apoptosis, cell proliferation, and stem cell self-renewal. Recently, the pathway has been shown to exert powerful growth regulatory activity in cardiomyocytes. However, the functional role of this stress-related and cell death-related pathway in the human heart and cardiomyocytes is not known. In this study, we investigated the role of the transcriptional co-activators of Hippo signalling, YAP and TAZ, in human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) in response to cardiotoxic agents and investigated the effects of modulating the pathway on cardiomyocyte function and survival. METHODS AND RESULTS RNA-sequencing analysis of human heart samples with doxorubicin-induced end-stage heart failure and healthy controls showed that YAP and ERBB2 (HER2) as upstream regulators of differentially expressed genes correlated with doxorubicin treatment. Thus, we tested the effects of doxorubicin on hiPSC-CMs in vitro. Using an automated high-content screen of 96 clinically relevant antineoplastic and cardiotherapeutic drugs, we showed that doxorubicin induced the highest activation of YAP/TAZ nuclear translocation in both hiPSC-CMs and control MCF7 breast cancer cells. The overexpression of YAP rescued doxorubicin-induced cell loss in hiPSC-CMs by inhibiting apoptosis and inducing proliferation. In contrast, silencing of YAP and TAZ by siRNAs resulted in elevated mitochondrial membrane potential loss in response to doxorubicin. hiPSC-CM calcium transients did not change in response to YAP/TAZ silencing. CONCLUSIONS Our results suggest that Hippo signalling is involved in clinical anthracycline-induced cardiomyopathy. Modelling with hiPSC-CMs in vitro showed similar responses to doxorubicin as adult cardiomyocytes and revealed a potential cardioprotective effect of YAP in doxorubicin-induced cardiotoxicity.
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Affiliation(s)
- Tünde Berecz
- Heart and Vascular CenterSemmelweis University68 Városmajor StreetBudapestH1122Hungary
- Institute of Enzymology, Research Centre for Natural SciencesEötvös Loránd Research NetworkBudapestHungary
| | - Angela Yiu
- Department of Surgery and CancerImperial College LondonLondonUK
| | - Orsolya Vittay
- National Heart and Lung InstituteImperial College LondonLondonUK
| | - Barbara Orsolits
- Heart and Vascular CenterSemmelweis University68 Városmajor StreetBudapestH1122Hungary
| | - Maxime Mioulane
- National Heart and Lung InstituteImperial College LondonLondonUK
| | - Cristobal G. dos Remedios
- Victor Chang Cardiac Research InstituteDarlinghurstNSWAustralia
- Bosch InstituteThe University of SydneySydneyNSWAustralia
| | - Robin Ketteler
- Laboratory for Molecular Cell BiologyUniversity College LondonLondonUK
| | - Bela Merkely
- Heart and Vascular CenterSemmelweis University68 Városmajor StreetBudapestH1122Hungary
| | - Ágota Apáti
- Institute of Enzymology, Research Centre for Natural SciencesEötvös Loránd Research NetworkBudapestHungary
| | - Sian E. Harding
- National Heart and Lung InstituteImperial College LondonLondonUK
| | - Nicola Hellen
- National Heart and Lung InstituteImperial College LondonLondonUK
| | - Gabor Foldes
- Heart and Vascular CenterSemmelweis University68 Városmajor StreetBudapestH1122Hungary
- National Heart and Lung InstituteImperial College LondonLondonUK
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3
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Sim CB, Phipson B, Ziemann M, Rafehi H, Mills RJ, Watt KI, Abu-Bonsrah KD, Kalathur RK, Voges HK, Dinh DT, ter Huurne M, Vivien CJ, Kaspi A, Kaipananickal H, Hidalgo A, Delbridge LM, Robker RL, Gregorevic P, dos Remedios CG, Lal S, Piers AT, Konstantinov IE, Elliott DA, El-Osta A, Oshlack A, Hudson JE, Porrello ER. Sex-Specific Control of Human Heart Maturation by the Progesterone Receptor. Circulation 2021; 143:1614-1628. [PMID: 33682422 PMCID: PMC8055196 DOI: 10.1161/circulationaha.120.051921] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 01/29/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Despite in-depth knowledge of the molecular mechanisms controlling embryonic heart development, little is known about the signals governing postnatal maturation of the human heart. METHODS Single-nucleus RNA sequencing of 54 140 nuclei from 9 human donors was used to profile transcriptional changes in diverse cardiac cell types during maturation from fetal stages to adulthood. Bulk RNA sequencing and the Assay for Transposase-Accessible Chromatin using sequencing were used to further validate transcriptional changes and to profile alterations in the chromatin accessibility landscape in purified cardiomyocyte nuclei from 21 human donors. Functional validation studies of sex steroids implicated in cardiac maturation were performed in human pluripotent stem cell-derived cardiac organoids and mice. RESULTS Our data identify the progesterone receptor as a key mediator of sex-dependent transcriptional programs during cardiomyocyte maturation. Functional validation studies in human cardiac organoids and mice demonstrate that the progesterone receptor drives sex-specific metabolic programs and maturation of cardiac contractile properties. CONCLUSIONS These data provide a blueprint for understanding human heart maturation in both sexes and reveal an important role for the progesterone receptor in human heart development.
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Affiliation(s)
- Choon Boon Sim
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Belinda Phipson
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Peter MacCallum Cancer Centre (B.P., A.O.), University of Melbourne, Victoria, Australia
| | - Mark Ziemann
- Department of Diabetes, Central Clinical School, Alfred Centre, Monash University, Melbourne, Victoria, Australia (M.Z., H.R., A.K., H.K., A.E.-O.)
- School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Victoria, Australia (M.Z.)
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (M.Z., H.R., K.I.W., A.K., H.K., P.G., A.E.-O.)
| | - Haloom Rafehi
- Department of Diabetes, Central Clinical School, Alfred Centre, Monash University, Melbourne, Victoria, Australia (M.Z., H.R., A.K., H.K., A.E.-O.)
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (M.Z., H.R., K.I.W., A.K., H.K., P.G., A.E.-O.)
| | - Richard J. Mills
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia (R.J.M., J.E.H.)
| | - Kevin I. Watt
- Peter MacCallum Cancer Centre (B.P., A.O.), University of Melbourne, Victoria, Australia
- Centre for Muscle Research (K.I.W., P.G., E.R.P.), University of Melbourne, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (M.Z., H.R., K.I.W., A.K., H.K., P.G., A.E.-O.)
| | - Kwaku D. Abu-Bonsrah
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- School of Biomedical Sciences, and Department of Paediatrics (K.D.A.-B., H.K.V., A.H., I.E.K., D.A.E.), University of Melbourne, Victoria, Australia
| | - Ravi K.R. Kalathur
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Holly K. Voges
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- School of Biomedical Sciences, and Department of Paediatrics (K.D.A.-B., H.K.V., A.H., I.E.K., D.A.E.), University of Melbourne, Victoria, Australia
| | - Doan T. Dinh
- Robinson Research Institute, The University of Adelaide, South Australia, Australia (D.T.D., R.L.R.)
| | - Menno ter Huurne
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Celine J. Vivien
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Antony Kaspi
- Department of Diabetes, Central Clinical School, Alfred Centre, Monash University, Melbourne, Victoria, Australia (M.Z., H.R., A.K., H.K., A.E.-O.)
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (M.Z., H.R., K.I.W., A.K., H.K., P.G., A.E.-O.)
| | - Harikrishnan Kaipananickal
- Department of Diabetes, Central Clinical School, Alfred Centre, Monash University, Melbourne, Victoria, Australia (M.Z., H.R., A.K., H.K., A.E.-O.)
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (M.Z., H.R., K.I.W., A.K., H.K., P.G., A.E.-O.)
| | - Alejandro Hidalgo
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- School of Biomedical Sciences, and Department of Paediatrics (K.D.A.-B., H.K.V., A.H., I.E.K., D.A.E.), University of Melbourne, Victoria, Australia
| | - Leanne M.D. Delbridge
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Department of Anatomy and Physiology (K.I.W., L.M.D.D., P.G., E.R.P.), University of Melbourne, Victoria, Australia
| | - Rebecca L. Robker
- Robinson Research Institute, The University of Adelaide, South Australia, Australia (D.T.D., R.L.R.)
| | - Paul Gregorevic
- Department of Anatomy and Physiology (K.I.W., L.M.D.D., P.G., E.R.P.), University of Melbourne, Victoria, Australia
- Centre for Muscle Research (K.I.W., P.G., E.R.P.), University of Melbourne, Victoria, Australia
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (M.Z., H.R., K.I.W., A.K., H.K., P.G., A.E.-O.)
| | - Cristobal G. dos Remedios
- School of Medical Sciences, The University of Sydney, New South Wales, Australia (C.G.d.R., S.L.)
- Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia (C.G.d.R.)
| | - Sean Lal
- School of Medical Sciences, The University of Sydney, New South Wales, Australia (C.G.d.R., S.L.)
| | - Adam T. Piers
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Igor E. Konstantinov
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Department of Cardiac Surgery (I.E.K.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- School of Biomedical Sciences, and Department of Paediatrics (K.D.A.-B., H.K.V., A.H., I.E.K., D.A.E.), University of Melbourne, Victoria, Australia
| | - David A. Elliott
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- School of Biomedical Sciences, and Department of Paediatrics (K.D.A.-B., H.K.V., A.H., I.E.K., D.A.E.), University of Melbourne, Victoria, Australia
| | - Assam El-Osta
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | - Alicia Oshlack
- Department of Diabetes, Central Clinical School, Alfred Centre, Monash University, Melbourne, Victoria, Australia (M.Z., H.R., A.K., H.K., A.E.-O.)
- Baker Heart and Diabetes Institute, Melbourne, Victoria, Australia (M.Z., H.R., K.I.W., A.K., H.K., P.G., A.E.-O.)
- Hong Kong Institute of Diabetes and Obesity, Prince of Wales Hospital, Li Ka Shing Institute of Health Sciences, and The Chinese University of Hong Kong, China (A.E.-O.)
| | - James E. Hudson
- QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia (R.J.M., J.E.H.)
- Centre for Cardiac and Vascular Biology, School of Biomedical Sciences, The University of Queensland, Brisbane, Australia (J.E.H., E.R.P.)
| | - Enzo R. Porrello
- Murdoch Children’s Research Institute (C.B.S., B.P., K.D.A.-B., R.K.R.K., H.K.V., M.t.H., C.J.V., A.H., A.T.P., I.E.K., D.A.E., A.O., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Melbourne Centre for Cardiovascular Genomics and Regenerative Medicine (C.B.S., K.D.A.-B., R.K.R.K., M.t.H., C.J.V., L.M.D.D., A.T.P., I.E.K., D.A.E., E.R.P.), The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Department of Anatomy and Physiology (K.I.W., L.M.D.D., P.G., E.R.P.), University of Melbourne, Victoria, Australia
- Centre for Muscle Research (K.I.W., P.G., E.R.P.), University of Melbourne, Victoria, Australia
- Centre for Cardiac and Vascular Biology, School of Biomedical Sciences, The University of Queensland, Brisbane, Australia (J.E.H., E.R.P.)
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4
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Vikhorev PG, Vikhoreva NN, Yeung W, Li A, Lal S, dos Remedios CG, Blair CA, Guglin M, Campbell KS, Yacoub MH, de Tombe P, Marston SB. Titin-truncating mutations associated with dilated cardiomyopathy alter length-dependent activation and its modulation via phosphorylation. Cardiovasc Res 2020; 118:241-253. [PMID: 33135063 PMCID: PMC8752363 DOI: 10.1093/cvr/cvaa316] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 10/20/2020] [Indexed: 12/18/2022] Open
Abstract
Abstract
Aims
Dilated cardiomyopathy (DCM) is associated with mutations in many genes encoding sarcomere proteins. Truncating mutations in the titin gene TTN are the most frequent. Proteomic and functional characterizations are required to elucidate the origin of the disease and the pathogenic mechanisms of TTN-truncating variants.
Methods and results
We isolated myofibrils from DCM hearts carrying truncating TTN mutations and measured the Ca2+ sensitivity of force and its length dependence. Simultaneous measurement of force and adenosine triphosphate (ATP) consumption in skinned cardiomyocytes was also performed. Phosphorylation levels of troponin I (TnI) and myosin binding protein-C (MyBP-C) were manipulated using protein kinase A and λ phosphatase. mRNA sequencing was employed to overview gene expression profiles. We found that Ca2+ sensitivity of myofibrils carrying TTN mutations was significantly higher than in myofibrils from donor hearts. The length dependence of the Ca2+ sensitivity was absent in DCM myofibrils with TTN-truncating variants. No significant difference was found in the expression level of TTN mRNA between the DCM and donor groups. TTN exon usage and splicing were also similar. However, we identified down-regulation of genes encoding Z-disk proteins, while the atrial-specific regulatory myosin light chain gene, MYL7, was up-regulated in DCM patients with TTN-truncating variants.
Conclusion
Titin-truncating mutations lead to decreased length-dependent activation and increased elasticity of myofibrils. Phosphorylation levels of TnI and MyBP-C seen in the left ventricles are essential for the length-dependent changes in Ca2+ sensitivity in healthy donors, but they are reduced in DCM patients with TTN-truncating variants. A decrease in expression of Z-disk proteins may explain the observed decrease in myofibril passive stiffness and length-dependent activation.
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Affiliation(s)
- Petr G Vikhorev
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Natalia N Vikhoreva
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK
| | - WaiChun Yeung
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Amy Li
- Department of Pharmacy and Biomedical Sciences, La Trobe University, Bendigo, VIC 3550, Australia
| | - Sean Lal
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, NSW 2006, Australia
| | - Cristobal G dos Remedios
- Division of Molecular Cardiology and Biophysics, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Cheavar A Blair
- Division of Cardiovascular Medicine, Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Maya Guglin
- Division of Cardiovascular Medicine, Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Kenneth S Campbell
- Division of Cardiovascular Medicine, Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Magdi H Yacoub
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Pieter de Tombe
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, IL, USA
| | - Steven B Marston
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London W12 0NN, UK
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5
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Brayson D, Holohan S, Bardswell SC, Arno M, Lu H, Jensen HK, Tran PK, Barallobre‐Barreiro J, Mayr M, dos Remedios CG, Tsang VT, Frigiola A, Kentish JC. Right Ventricle Has Normal Myofilament Function But Shows Perturbations in the Expression of Extracellular Matrix Genes in Patients With Tetralogy of Fallot Undergoing Pulmonary Valve Replacement. J Am Heart Assoc 2020; 9:e015342. [PMID: 32805183 PMCID: PMC7660801 DOI: 10.1161/jaha.119.015342] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 05/28/2020] [Indexed: 02/06/2023]
Abstract
Background Patients with repair of tetralogy of Fallot (rToF) who are approaching adulthood often exhibit pulmonary valve regurgitation, leading to right ventricle (RV) dilatation and dysfunction. The regurgitation can be corrected by pulmonary valve replacement (PVR), but the optimal surgical timing remains under debate, mainly because of the poorly understood nature of RV remodeling in patients with rToF. The goal of this study was to probe for pathologic molecular, cellular, and tissue changes in the myocardium of patients with rToF at the time of PVR. Methods and Results We measured contractile function of permeabilized myocytes, collagen content of tissue samples, and the expression of mRNA and selected proteins in RV tissue samples from patients with rToF undergoing PVR for severe pulmonary valve regurgitation. The data were compared with nondiseased RV tissue from unused donor hearts. Contractile performance and passive stiffness of the myofilaments in permeabilized myocytes were similar in rToF-PVR and RV donor samples, as was collagen content and cross-linking. The patients with rToF undergoing PVR had enhanced mRNA expression of genes associated with connective tissue diseases and tissue remodeling, including the small leucine-rich proteoglycans ASPN (asporin), LUM (lumican), and OGN (osteoglycin), although their protein levels were not significantly increased. Conclusions RV myofilaments from patients with rToF undergoing PVR showed no functional impairment, but the changes in extracellular matrix gene expression may indicate the early stages of remodeling. Our study found no evidence of major damage at the cellular and tissue levels in the RV of patients with rToF who underwent PVR according to current clinical criteria.
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Affiliation(s)
- Daniel Brayson
- School of Cardiovascular Medicine and SciencesKing's College London BHF Centre for Research ExcellenceLondonUnited Kingdom
| | - So‐Jin Holohan
- School of Cardiovascular Medicine and SciencesKing's College London BHF Centre for Research ExcellenceLondonUnited Kingdom
| | - Sonya C. Bardswell
- School of Cardiovascular Medicine and SciencesKing's College London BHF Centre for Research ExcellenceLondonUnited Kingdom
| | - Matthew Arno
- Genomics CentreFaculty of Life Sciences and MedicineKing’s College LondonLondonUnited Kingdom
| | - Han Lu
- Genomics CentreFaculty of Life Sciences and MedicineKing’s College LondonLondonUnited Kingdom
| | | | | | - Javier Barallobre‐Barreiro
- School of Cardiovascular Medicine and SciencesKing's College London BHF Centre for Research ExcellenceLondonUnited Kingdom
| | - Manuel Mayr
- School of Cardiovascular Medicine and SciencesKing's College London BHF Centre for Research ExcellenceLondonUnited Kingdom
| | | | | | - Alessandra Frigiola
- Great Ormond Street HospitalLondonUnited Kingdom
- Guys and St Thomas’ NHS Foundation TrustSt Thomas’ HospitalLondonUnited Kingdom
- School of Biomedical Engineering and Imaging SciencesKings CollegeLondonUnited Kingdom
| | - Jonathan C. Kentish
- School of Cardiovascular Medicine and SciencesKing's College London BHF Centre for Research ExcellenceLondonUnited Kingdom
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6
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Brayson D, Frustaci A, Verardo R, Chimenti C, Russo MA, Hayward R, Ahmad S, Vizcay-Barrena G, Protti A, Zammit PS, dos Remedios CG, Ehler E, Shah AM, Shanahan CM. Prelamin A mediates myocardial inflammation in dilated and HIV-associated cardiomyopathies. JCI Insight 2019; 4:126315. [PMID: 31622279 PMCID: PMC6948859 DOI: 10.1172/jci.insight.126315] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Accepted: 10/08/2019] [Indexed: 12/13/2022] Open
Abstract
Cardiomyopathies are complex heart muscle diseases that can be inherited or acquired. Dilated cardiomyopathy can result from mutations in LMNA, encoding the nuclear intermediate filament proteins lamin A/C. Some LMNA mutations lead to accumulation of the lamin A precursor, prelamin A, which is disease causing in a number of tissues, yet its impact upon the heart is unknown. Here, we discovered myocardial prelamin A accumulation occurred in a case of dilated cardiomyopathy, and we show that a potentially novel mouse model of cardiac-specific prelamin A accumulation exhibited a phenotype consistent with inflammatory cardiomyopathy, which we observed to be similar to HIV-associated cardiomyopathy, an acquired disease state. Numerous HIV protease therapies are known to inhibit ZMPSTE24, the enzyme responsible for prelamin A processing, and we confirmed that accumulation of prelamin A occurred in HIV+ patient cardiac biopsies. These findings (a) confirm a unifying pathological role for prelamin A common to genetic and acquired cardiomyopathies; (b) have implications for the management of HIV patients with cardiac disease, suggesting protease inhibitors should be replaced with alternative therapies (i.e., nonnucleoside reverse transcriptase inhibitors); and (c) suggest that targeting inflammation may be a useful treatment strategy for certain forms of inherited cardiomyopathy.
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Affiliation(s)
- Daniel Brayson
- School of Cardiovascular Medicine and Sciences, King's College London BHF Centre for Research Excellence, London, United Kingdom
| | - Andrea Frustaci
- Department of Cardiovascular, Nefrologic, Anestesiologic and Geriatric Sciences, La Sapienza University of Rome, Italy.,National Institute for Infectious Diseases IRCCS "L. Spallanzani", Rome, Italy
| | - Romina Verardo
- National Institute for Infectious Diseases IRCCS "L. Spallanzani", Rome, Italy
| | - Cristina Chimenti
- Department of Cardiovascular, Nefrologic, Anestesiologic and Geriatric Sciences, La Sapienza University of Rome, Italy.,National Institute for Infectious Diseases IRCCS "L. Spallanzani", Rome, Italy
| | - Matteo Antonio Russo
- MEBIC Open University San Raffaele and IRCCS San Raffaele Pisana, Laboratory of Molecular and Cellular Pathology, Milan, Italy
| | - Robert Hayward
- School of Cardiovascular Medicine and Sciences, King's College London BHF Centre for Research Excellence, London, United Kingdom
| | - Sadia Ahmad
- School of Cardiovascular Medicine and Sciences, King's College London BHF Centre for Research Excellence, London, United Kingdom
| | | | - Andrea Protti
- School of Cardiovascular Medicine and Sciences, King's College London BHF Centre for Research Excellence, London, United Kingdom
| | - Peter S Zammit
- Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | | | - Elisabeth Ehler
- School of Cardiovascular Medicine and Sciences, King's College London BHF Centre for Research Excellence, London, United Kingdom.,Randall Centre for Cell and Molecular Biophysics, King's College London, London, United Kingdom
| | - Ajay M Shah
- School of Cardiovascular Medicine and Sciences, King's College London BHF Centre for Research Excellence, London, United Kingdom
| | - Catherine M Shanahan
- School of Cardiovascular Medicine and Sciences, King's College London BHF Centre for Research Excellence, London, United Kingdom
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7
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Dorsch LM, Schuldt M, dos Remedios CG, Schinkel AFL, de Jong PL, Michels M, Kuster DWD, Brundel BJJM, van der Velden J. Protein Quality Control Activation and Microtubule Remodeling in Hypertrophic Cardiomyopathy. Cells 2019; 8:E741. [PMID: 31323898 PMCID: PMC6678711 DOI: 10.3390/cells8070741] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder. It is mainly caused by mutations in genes encoding sarcomere proteins. Mutant forms of these highly abundant proteins likely stress the protein quality control (PQC) system of cardiomyocytes. The PQC system, together with a functional microtubule network, maintains proteostasis. We compared left ventricular (LV) tissue of nine donors (controls) with 38 sarcomere mutation-positive (HCMSMP) and 14 sarcomere mutation-negative (HCMSMN) patients to define HCM and mutation-specific changes in PQC. Mutations in HCMSMP result in poison polypeptides or reduced protein levels (haploinsufficiency, HI). The main findings were 1) several key PQC players were more abundant in HCM compared to controls, 2) after correction for sex and age, stabilizing heat shock protein (HSP)B1, and refolding, HSPD1 and HSPA2 were increased in HCMSMP compared to controls, 3) α-tubulin and acetylated α-tubulin levels were higher in HCM compared to controls, especially in HCMHI, 4) myosin-binding protein-C (cMyBP-C) levels were inversely correlated with α-tubulin, and 5) α-tubulin levels correlated with acetylated α-tubulin and HSPs. Overall, carrying a mutation affects PQC and α-tubulin acetylation. The haploinsufficiency of cMyBP-C may trigger HSPs and α-tubulin acetylation. Our study indicates that proliferation of the microtubular network may represent a novel pathomechanism in cMyBP-C haploinsufficiency-mediated HCM.
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Affiliation(s)
- Larissa M Dorsch
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands.
| | - Maike Schuldt
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Cristobal G dos Remedios
- Sydney Heart Bank, Discipline of Anatomy, Bosch Institute, University of Sydney, Sydney 2006, Australia
| | - Arend F L Schinkel
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Peter L de Jong
- Department of Cardiothoracic Surgery, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Michelle Michels
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
- Netherlands Heart Institute, 3511 EP Utrecht, The Netherlands
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8
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Vikhorev PG, Li A, Lal S, dos Remedios CG, Marston SB. Effect of Truncated Mutations in the Titin Gene on Cardiac Function. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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9
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Huang ZP, Ding Y, Chen J, Wu G, Kataoka M, Hu Y, Yang JH, Liu J, Drakos SG, Selzman CH, Kyselovic J, Qu LH, dos Remedios CG, Pu WT, Wang DZ. Long non-coding RNAs link extracellular matrix gene expression to ischemic cardiomyopathy. Cardiovasc Res 2016; 112:543-554. [PMID: 27557636 PMCID: PMC5079274 DOI: 10.1093/cvr/cvw201] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 08/04/2016] [Accepted: 08/18/2016] [Indexed: 12/20/2022] Open
Abstract
AIMS Ischemic cardiomyopathy (ICM) resulting from myocardial infarction is a major cause of heart failure (HF). Recently, thousands of long non-coding RNAs (lncRNAs) have been discovered and implicated in a variety of biological processes. However, the role of most lncRNAs in HF remains largely unknown. The aim of this study is to test the hypothesis that the expression and function of lncRNAs are differentially regulated in diseased hearts. METHODS AND RESULTS In this study, we performed RNA deep sequencing of protein-coding and non-coding RNAs from cardiac samples of patients with ICM ( n = 15) and controls ( n = 15). Genome-wide transcriptome analysis confirmed that many protein-coding genes previously known to be involved in HF were altered in ICM hearts. Among the 145 differentially expressed lncRNAs identified in ICM hearts, we found a set of 35 lncRNAs that display strong positive expression correlation. Expression correlation coefficient analyses of differentially expressed lncRNAs and protein-coding genes revealed a strong association between lncRNAs and extracellular matrix (ECM) protein-coding genes. We overexpressed or knocked down selected lncRNAs in cardiac fibroblasts and our results suggest that lncRNAs are important regulators of fibrosis and the expression of ECM synthesis genes. Moreover, we show that lncRNAs participate in the TGF-β pathway to modulate the expression of ECM genes and myofibroblast differentiation. CONCLUSION Our studies demonstrate that the expression of many lncRNAs is dynamically regulated in ICM. lncRNAs regulate the expression and function of ECM and cardiac fibrosis during the development of ICM. Our results further indicate that lncRNAs may represent novel regulators of heart function and cardiac disorders, including ICM.
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Affiliation(s)
- Zhan-Peng Huang
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
| | - Yan Ding
- The Institute for Translational Medicine and Therapeutics, The Affiliated Zhongshan Hospital of Dalian University, 6 Jiefang Street, Zhongshan District, Dalian 116001, China
| | - Jinghai Chen
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
- Department of Cardiology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310009, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou 310029, China
| | - Gengze Wu
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
| | - Masaharu Kataoka
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Yongwu Hu
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
| | - Jian-Hua Yang
- RNA Information Center, Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, PR China
| | - Jianming Liu
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
| | - Stavros G. Drakos
- Division of Cardiovascular Medicine, Department of Internal Medicine
| | - Craig H. Selzman
- Division of Cardiothoracic Surgery, Department of Surgery, University of Utah School of Medicine, Salt Lake City, UT 84132, USA
| | - Jan Kyselovic
- Faculty of Pharmacy, Comenius University, Bratislava, Slovak Republic
| | - Liang-Hu Qu
- RNA Information Center, Key Laboratory of Gene Engineering of the Ministry of Education, State Key Laboratory for Biocontrol, Sun Yat-sen University, Guangzhou 510275, PR China
| | | | - William T. Pu
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
| | - Da-Zhi Wang
- Department of Cardiology, Boston Children's Hospital, Harvard Medical School, 320 Longwood Avenue, Boston, MA 02115, USA
- Harvard Stem Cell Institute, Harvard University, Cambridge, MA 02138, USA
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10
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11
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Kraft T, Makul M, Beck J, Montag J, Radocaj A, Perrot A, Francino A, Navarro-Lopéz F, dos Remedios CG, Brenner B. Functional Imbalance among Individual Cardiomyocytes Caused by Cell-to-Cell Variation in Mutant mRNA Expression. A Possible Trigger for Hypertrophic Cardiomyopathy. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.1973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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12
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Polizzotti BD, Ganapathy B, Walsh S, Choudhury S, Ammanamanchi N, Bennett DG, dos Remedios CG, Haubner BJ, Penninger JM, Kühn B. Neuregulin stimulation of cardiomyocyte regeneration in mice and human myocardium reveals a therapeutic window. Sci Transl Med 2015; 7:281ra45. [PMID: 25834111 DOI: 10.1126/scitranslmed.aaa5171] [Citation(s) in RCA: 161] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Therapies developed for adult patients with heart failure have been shown to be ineffective in pediatric clinical trials, leading to the recognition that new pediatric-specific therapies for heart failure must be developed. Administration of the recombinant growth factor neuregulin-1 (rNRG1) stimulates regeneration of heart muscle cells (cardiomyocytes) in adult mice. Because proliferation-competent cardiomyocytes are more abundant in growing mammals, we hypothesized that administration of rNRG1 during the neonatal period might be more effective than in adulthood. If so, neonatal rNRG1 delivery could be a new therapeutic strategy for treating heart failure in pediatric patients. To evaluate the effectiveness of rNRG1 administration in cardiac regeneration, newborn mice were subjected to cryoinjury, which induced myocardial dysfunction and scar formation and decreased cardiomyocyte cell cycle activity. Early administration of rNRG1 to mice from birth to 34 days of age improved myocardial function and reduced the prevalence of transmural scars. In contrast, administration of rNRG1 from 4 to 34 days of age only transiently improved myocardial function. The mechanisms of early administration involved cardiomyocyte protection (38%) and proliferation (62%). We also assessed the ability of rNRG1 to stimulate cardiomyocyte proliferation in intact cultured myocardium from pediatric patients. rNRG1 induced cardiomyocyte proliferation in myocardium from infants with heart disease who were less than 6 months of age. Our results identify an effective time period within which to execute rNRG1 clinical trials in pediatric patients for the stimulation of cardiomyocyte regeneration.
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Affiliation(s)
- Brian D Polizzotti
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA. Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Balakrishnan Ganapathy
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA. Department of Pediatrics, University of Pittsburgh, and Richard King Mellon Institute for Pediatric Research and Division of Pediatric Cardiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - Stuart Walsh
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA. Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Sangita Choudhury
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA. Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Niyatie Ammanamanchi
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA. Department of Pediatrics, University of Pittsburgh, and Richard King Mellon Institute for Pediatric Research and Division of Pediatric Cardiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA
| | - David G Bennett
- Preclinical MRI Core, Beth Israel Deaconess Medical Center, Boston, MA 02115, USA
| | - Cristobal G dos Remedios
- Department of Anatomy, Bosch Institute, The University of Sydney, Sydney, New South Wales 2006, Australia
| | - Bernhard J Haubner
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Josef M Penninger
- Institute of Molecular Biotechnology of the Austrian Academy of Sciences, 1030 Vienna, Austria
| | - Bernhard Kühn
- Department of Cardiology, Boston Children's Hospital, Boston, MA 02115, USA. Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA. Department of Pediatrics, University of Pittsburgh, and Richard King Mellon Institute for Pediatric Research and Division of Pediatric Cardiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA 15224, USA. Harvard Stem Cell Institute, Cambridge, MA 02138, USA. Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, MA 02138, USA. McGowan Institute for Regenerative Medicine, Pittsburgh, PA 15219, USA.
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13
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Mamidi R, Gresham KS, Li A, dos Remedios CG, Stelzer JE. Molecular effects of the myosin activator omecamtiv mecarbil on contractile properties of skinned myocardium lacking cardiac myosin binding protein-C. J Mol Cell Cardiol 2015; 85:262-72. [PMID: 26100051 DOI: 10.1016/j.yjmcc.2015.06.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 05/28/2015] [Accepted: 06/15/2015] [Indexed: 01/03/2023]
Abstract
Decreased expression of cardiac myosin binding protein-C (cMyBP-C) in the myocardium is thought to be a contributing factor to hypertrophic cardiomyopathy in humans, and the initial molecular defect is likely abnormal cross-bridge (XB) function which leads to impaired force generation, decreased contractile performance, and hypertrophy in vivo. The myosin activator omecamtiv mecarbil (OM) is a pharmacological drug that specifically targets the myosin XB and recent evidence suggests that OM induces a significant decrease in the in vivo motility velocity and an increase in the XB duty cycle. Thus, the molecular effects of OM maybe beneficial in improving contractile function in skinned myocardium lacking cMyBP-C because absence of cMyBP-C in the sarcomere accelerates XB kinetics and enhances XB turnover rate, which presumably reduces contractile efficiency. Therefore, parameters of XB function were measured in skinned myocardium lacking cMyBP-C prior to and following OM incubation. We measured ktr, the rate of force redevelopment as an index of XB transition from both the weakly- to strongly-bound state and from the strongly- to weakly-bound states and performed stretch activation experiments to measure the rates of XB detachment (krel) and XB recruitment (kdf) in detergent-skinned ventricular preparations isolated from hearts of wild-type (WT) and cMyBP-C knockout (KO) mice. Samples from donor human hearts were also used to assess the effects of OM in cardiac muscle expressing a slow β-myosin heavy chain (β-MHC). Incubation of skinned myocardium with OM produced large enhancements in steady-state force generation which were most pronounced at low levels of [Ca(2+)] activations, suggesting that OM cooperatively recruits additional XB's into force generating states. Despite a large increase in steady-state force generation following OM incubation, parallel accelerations in XB kinetics as measured by ktr were not observed, and there was a significant OM-induced decrease in krel which was more pronounced in the KO skinned myocardium compared to WT skinned myocardium (58% in WT vs. 76% in KO at pCa 6.1), such that baseline differences in krel between KO and WT skinned myocardium were no longer apparent following OM-incubation. A significant decrease in the kdf was also observed following OM incubation in all groups, which may be related to the increase in the number of cooperatively recruited XB's at low Ca(2+)-activations which slows the overall rate of force generation. Our results indicate that OM may be a useful pharmacological approach to normalize hypercontractile XB kinetics in myocardium with decreased cMyBP-C expression due to its molecular effects on XB behavior.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Kenneth S Gresham
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Amy Li
- Muscle Research Unit, Bosch Institute, University of Sydney, Sydney Australia
| | | | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA.
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Wijnker PJM, Sequeira V, Witjas-Paalberends ER, Foster DB, dos Remedios CG, Murphy AM, Stienen GJM, van der Velden J. Phosphorylation of protein kinase C sites Ser42/44 decreases Ca(2+)-sensitivity and blunts enhanced length-dependent activation in response to protein kinase A in human cardiomyocytes. Arch Biochem Biophys 2014; 554:11-21. [PMID: 24814372 PMCID: PMC4121669 DOI: 10.1016/j.abb.2014.04.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/29/2014] [Accepted: 04/29/2014] [Indexed: 10/25/2022]
Abstract
Protein kinase C (PKC)-mediated phosphorylation of troponin I (cTnI) at Ser42/44 is increased in heart failure. While studies in rodents demonstrated that PKC-mediated Ser42/44 phosphorylation decreases maximal force and ATPase activity, PKC incubation of human cardiomyocytes did not affect maximal force. We investigated whether Ser42/44 pseudo-phosphorylation affects force development and ATPase activity using troponin exchange in human myocardium. Additionally, we studied if pseudo-phosphorylated Ser42/44 modulates length-dependent activation of force, which is regulated by protein kinase A (PKA)-mediated cTnI-Ser23/24 phosphorylation. Isometric force was measured in membrane-permeabilized cardiomyocytes exchanged with human recombinant wild-type troponin or troponin mutated at Ser42/44 or Ser23/24 into aspartic acid (D) or alanine (A) to mimic phosphorylation and dephosphorylation, respectively. In troponin-exchanged donor cardiomyocytes experiments were repeated after PKA incubation. ATPase activity was measured in troponin-exchanged cardiac muscle strips. Compared to wild-type, 42D/44D decreased Ca(2+)-sensitivity without affecting maximal force in failing and donor cardiomyocytes. In donor myocardium, 42D/44D did not affect maximal ATPase activity or tension cost. Interestingly, 42D/44D blunted the length-dependent increase in Ca(2+)-sensitivity induced upon PKA-mediated phosphorylation. Since the drop in Ca(2+)-sensitivity at physiological Ca(2+)-concentrations is relatively large phosphorylation of Ser42/44 may result in a decrease of force and associated ATP utilization in the human heart.
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Affiliation(s)
- Paul J M Wijnker
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| | - Vasco Sequeira
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands.
| | - E Rosalie Witjas-Paalberends
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands.
| | - D Brian Foster
- Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Ross Bldg 1144/720 Rutland Avenue, Baltimore, MD 21205, USA.
| | | | - Anne M Murphy
- Department of Pediatrics/Division of Cardiology, Johns Hopkins University School of Medicine, Ross Bldg 1144/720 Rutland Avenue, Baltimore, MD 21205, USA.
| | - Ger J M Stienen
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; Department of Physics and Astronomy, VU University, Amsterdam, The Netherlands.
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands; ICIN-Netherlands Heart Institute, Utrecht, The Netherlands.
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15
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Gentile C, Kuehn B, Davies MJ, dos Remedios CG. A Novel Method for Isolating and Culturing Human Cardiomyocytes from Cryopreserved Tissues. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.3132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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16
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Li A, Bos JM, Ackerman MJ, Braet F, Kekic M, Ishiwata S, dos Remedios CG. Depressed Contractility at Low-Load Spontaneous Oscillatory Contractions in Human Hypertrophic Cardiomyopathy with MYBPC3 Mutations. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.1979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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17
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Lin MW, Ho JWK, Harrison LC, dos Remedios CG, Adelstein S. An antibody-based leukocyte-capture microarray for the diagnosis of systemic lupus erythematosus. PLoS One 2013; 8:e58199. [PMID: 23516448 PMCID: PMC3596412 DOI: 10.1371/journal.pone.0058199] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Accepted: 02/01/2013] [Indexed: 12/17/2022] Open
Abstract
The diagnosis of Systemic Lupus Erythematosus (SLE) is challenging due to its heterogeneous clinical presentation and the lack of robust biomarkers to distinguish it from other autoimmune diseases. Further, currently used laboratory tests do not readily distinguish active and inactive disease. Several groups have attempted to apply emerging high throughput profiling technologies to diagnose and monitor SLE. Despite showing promise, many are expensive and technically challenging for routine clinical use. The goal of this work is to develop a better diagnostic and monitoring tool for SLE. We report a highly customisable antibody microarray that consists of a duplicate arrangement of 82 antibodies directed against surface antigens on peripheral blood mononuclear cells (PMBCs). This high-throughput array was used to profile SLE patients (n = 60) with varying disease activity, compared to healthy controls (n = 24), patients with rheumatoid arthritis (n = 25), and other autoimmune diseases (n = 28). We used a computational algorithm to calculate a score from the entire microarray profile and correlated it with SLE disease activity. Our results demonstrate that leukocyte-capture microarray profiles can readily distinguish active SLE patients from healthy controls (AUROC = 0.84). When combined with the standard laboratory tests (serum anti-dsDNA, complements C3 and C4), the microarrays provide significantly increased discrimination. The antibody microarrays can be enhanced by the addition of other markers for potential application to the diagnosis and stratification of SLE, paving the way for the customised and accurate diagnosis and monitoring of SLE.
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Affiliation(s)
- Ming-Wei Lin
- Department of Clinical Immunology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
- Discipline of Medicine, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - Joshua W. K. Ho
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Leonard C. Harrison
- The Walter and Eliza Hall Institute of Medical Research, Department of Clinical Immunology and Burnet Clinical Research Unit, The Royal Melbourne Hospital, Parkville, Victoria, Australia
| | - Cristobal G. dos Remedios
- Discipline of Anatomy, Bosch Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Stephen Adelstein
- Department of Clinical Immunology, Royal Prince Alfred Hospital, Sydney, New South Wales, Australia
- Discipline of Medicine, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
- * E-mail:
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Li A, King D, Kable E, Kagemoto T, van der Velden J, Dooijes D, Macdonald PS, Braet F, Ishiwata S, dos Remedios CG. A New Functional Measure of Contractility in Human Cardiomyopathies. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Li A, King D, Braet F, Ishiwata S, Remedios CGD, Harris SP. A New Way to Examine the Function of Mutant MYBPC3 Expression in Cardiomyocytes of Mice. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.1718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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20
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Gomez-Arroyo J, Mizuno S, Szczepanek K, Van Tassell B, Natarajan R, dos Remedios CG, Drake JI, Farkas L, Kraskauskas D, Wijesinghe DS, Chalfant CE, Bigbee J, Abbate A, Lesnefsky EJ, Bogaard HJ, Voelkel NF. Metabolic gene remodeling and mitochondrial dysfunction in failing right ventricular hypertrophy secondary to pulmonary arterial hypertension. Circ Heart Fail 2012; 6:136-44. [PMID: 23152488 DOI: 10.1161/circheartfailure.111.966127] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Right ventricular (RV) dysfunction (RVD) is the most frequent cause of death in patients with pulmonary arterial hypertension. Although abnormal energy substrate use has been implicated in the development of chronic left heart failure, data describing such metabolic remodeling in RVD remain incomplete. Thus, we sought to characterize metabolic gene expression changes and mitochondrial dysfunction in functional and dysfunctional RV hypertrophy. METHODS AND RESULTS Two different rat models of RV hypertrophy were studied. The model of RVD (SU5416/hypoxia) exhibited a significantly decreased gene expression of peroxisome proliferator-activated receptor-γ coactivator-1α, peroxisome proliferator-activated receptor-α and estrogen-related receptor-α. The expression of multiple peroxisome proliferator-activated receptor-γ coactivator-1α target genes required for fatty acid oxidation was similarly decreased. Decreased peroxisome proliferator-activated receptor-γ coactivator-1α expression was also associated with a net loss of mitochondrial protein and oxidative capacity. Reduced mitochondrial number was associated with a downregulation of transcription factor A, mitochondrial, and other genes required for mitochondrial biogenesis. Electron microscopy demonstrated that, in RVD tissue, mitochondria had abnormal shape and size. Lastly, respirometric analysis demonstrated that mitochondria isolated from RVD tissue had a significantly reduced ADP-stimulated (state 3) rate for complex I. Conversely, functional RV hypertrophy in the pulmonary artery banding model showed normal expression of peroxisome proliferator-activated receptor-γ coactivator-1α, whereas the expression of fatty acid oxidation genes was either preserved or unregulated. Moreover, pulmonary artery banding-RV tissue exhibited preserved transcription factor A mitochondrial expression and mitochondrial respiration despite elevated RV pressure-overload. CONCLUSIONS Right ventricular dysfunction, but not functional RV hypertrophy in rats, demonstrates a gene expression profile compatible with a multilevel impairment of fatty acid metabolism and significant mitochondrial dysfunction, partially independent of chronic pressure-overload.
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Affiliation(s)
- Jose Gomez-Arroyo
- Victoria Johnson Center for Lung Obstructive Disease Research, Virginia Commonwealth University, Richmond, VA 23298, USA
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Wijnker PJM, Foster DB, Tsao AL, Frazier AH, dos Remedios CG, Murphy AM, Stienen GJM, van der Velden J. Impact of site-specific phosphorylation of protein kinase A sites Ser23 and Ser24 of cardiac troponin I in human cardiomyocytes. Am J Physiol Heart Circ Physiol 2012; 304:H260-8. [PMID: 23144315 DOI: 10.1152/ajpheart.00498.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
PKA-mediated phosphorylation of contractile proteins upon β-adrenergic stimulation plays an important role in the regulation of cardiac performance. Phosphorylation of the PKA sites (Ser(23)/Ser(24)) of cardiac troponin (cTn)I results in a decrease in myofilament Ca(2+) sensitivity and an increase in the rate of relaxation. However, the relation between the level of phosphorylation of the sites and the functional effects in the human myocardium is unknown. Therefore, site-directed mutagenesis was used to study the effects of phosphorylation at Ser(23) and Ser(24) of cTnI on myofilament function in human cardiac tissue. Serines were replaced by aspartic acid (D) or alanine (A) to mimic phosphorylation and dephosphorylation, respectively. cTnI-DD mimics both sites phosphorylated, cTnI-AD mimics Ser(23) unphosphorylated and Ser(24) phosphorylated, cTnI-DA mimics Ser(23) phosphorylated and Ser(24) unphosphorylated, and cTnI-AA mimics both sites unphosphorylated. Force development was measured at various Ca(2+) concentrations in permeabilized cardiomyocytes in which the endogenous troponin complex was exchanged with these recombinant human troponin complexes. In donor cardiomyocytes, myofilament Ca(2+) sensitivity (pCa(50)) was significantly lower in cTnI-DD (pCa(50): 5.39 ± 0.01) compared with cTnI-AA (pCa(50): 5.50 ± 0.01), cTnI-AD (pCa(50): 5.48 ± 0.01), and cTnI-DA (pCa(50): 5.51 ± 0.01) at ~70% cTn exchange. No effects were observed on the rate of tension redevelopment. In cardiomyocytes from idiopathic dilated cardiomyopathic tissue, a linear decline in pCa(50) with cTnI-DD content was observed, saturating at ~55% bisphosphorylation. Our data suggest that in the human myocardium, phosphorylation of both PKA sites on cTnI is required to reduce myofilament Ca(2+) sensitivity, which is maximal at ~55% bisphosphorylated cTnI. The implications for in vivo cardiac function in health and disease are detailed in the DISCUSSION in this article.
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Affiliation(s)
- Paul J M Wijnker
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands.
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Zhang P, Kirk JA, Ji W, dos Remedios CG, Kass DA, Van Eyk JE, Murphy AM. Multiple reaction monitoring to identify site-specific troponin I phosphorylated residues in the failing human heart. Circulation 2012; 126:1828-37. [PMID: 22972900 DOI: 10.1161/circulationaha.112.096388] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Human cardiac troponin I is known to be phosphorylated at multiple amino acid residues by several kinases. Advances in mass spectrometry allow sensitive detection of known and novel phosphorylation sites and measurement of the level of phosphorylation simultaneously at each site in myocardial samples. METHODS AND RESULTS On the basis of in silico prediction and liquid chromatography/mass spectrometry data, 14 phosphorylation sites on cardiac troponin I, including 6 novel residues (S4, S5, Y25, T50, T180, S198), were assessed in explanted hearts from end-stage heart failure transplantation patients with ischemic heart disease or idiopathic dilated cardiomyopathy and compared with samples obtained from nonfailing donor hearts (n=10 per group). Thirty mass spectrometry-based multiple reaction monitoring quantitative tryptic peptide assays were developed for each phosphorylatable and corresponding nonphosphorylated site. The results show that in heart failure there is a decrease in the extent of phosphorylation of the known protein kinase A sites (S22, S23) and other newly discovered phosphorylation sites located in the N-terminal extension of cardiac troponin I (S4, S5, Y25), an increase in phosphorylation of the protein kinase C sites (S41, S43, T142), and an increase in phosphorylation of the IT-arm domain residues (S76, T77) and C-terminal domain novel phosphorylation sites of cardiac troponin I (S165, T180, S198). In a canine dyssynchronous heart failure model, enhanced phosphorylation at 3 novel sites was found to decline toward control after resynchronization therapy. CONCLUSIONS Selective, functionally significant phosphorylation alterations occurred on individual residues of cardiac troponin I in heart failure, likely reflecting an imbalance in kinase/phosphatase activity. Such changes can be reversed by cardiac resynchronization.
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Affiliation(s)
- Pingbo Zhang
- Department of Medicine, Division of Cardiology, Johns Hopkins University, Baltimore, MD, USA
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Wriggers W, Olson WK, dos Remedios CG. Computational opportunities for remote collaboration and capacity building afforded by Web 2.0 and cloud computing. Biophys Rev 2012; 4:153-160. [PMID: 23066431 PMCID: PMC3467109 DOI: 10.1007/s12551-012-0085-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 06/07/2012] [Indexed: 10/28/2022] Open
Abstract
In this paper, we state our aims and aspirations for building a global network of likeminded people interested in developing and encouraging students in the field of computational biophysics (CB). Global capacity building efforts have uncovered local computational talent in virtually every community regardless of where the students reside. Our vision is to discover and encourage these aspiring investigators by suggesting ways that they and other "garage scientists" can participate in new science even if they have no access to sophisticated research infrastructure. We argue that participatory computing in the "cloud" is particularly suitable for CB and available to any budding computational biophysicist if he or she is provided with open-minded mentors who have the necessary skills and generosity. We recognize that there are barriers to the development of such remote collaborations, and we discuss possible pathways to overcome these barriers. We point out that this Special Issue of Biophysical Reviews provides a much-needed forum for the development of several specific applications of CB.
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Affiliation(s)
- Willy Wriggers
- Department of Physiology and Biophysics and Institute for Computational Biomedicine, Weill Medical College of Cornell University, 1300 York Ave, New York, NY 10065 USA
- D. E. Shaw Research, 120 West 45th Street, New York, NY 10036 USA
| | - Wilma K. Olson
- Department of Chemistry and Chemical Biology, BioMaPS Institute for Quantitative Biology, Wright-Rieman Laboratories, Rutgers University, 610 Taylor Road, Piscataway, NJ 08854-8087 USA
| | - Cristobal G. dos Remedios
- Discipline of Anatomy and Histology & School of Medical Sciences, Bosch Institute (F13), University of Sydney, Sydney, 2006 Australia
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Li A, Ponten F, dos Remedios CG. The interactome of LIM domain proteins: The contributions of LIM domain proteins to heart failure and heart development. Proteomics 2012; 12:203-25. [DOI: 10.1002/pmic.201100492] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/07/2011] [Accepted: 11/08/2011] [Indexed: 12/22/2022]
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Li A, Wolfe JE, Kable E, Braet F, King DA, Kagemoto T, Macdonald PS, Ishiwata S, dos Remedios CG. Heart of the Matter: Assessing Human Cardiomyopathies with Spontaneous Oscillatory Contractions (SPOC). Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022] Open
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26
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Foreman AL, Phillips L, Kanellis VG, Hammoudeh D, Naumann C, Wong H, Chisari R, Hibbert DB, Lee GSH, Patra R, Julli M, Chapman J, Cooke AR, dos Remedios CG. A DNA-based assay for toxic chemicals in wastewater. Environ Toxicol Chem 2011; 30:1810-1818. [PMID: 21560144 DOI: 10.1002/etc.568] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2010] [Revised: 01/06/2011] [Accepted: 03/14/2011] [Indexed: 05/30/2023]
Abstract
Chemical toxicants, particularly metal ions, are a major contaminant in global waterways. Live-organism bioassays used to monitor chemical toxicants commonly involve measurements of activity or survival of a freshwater cladoceran (Ceriodaphnia dubia) or light emitted by the marine bacterium Vibrio fischeri, used in the commercial Microtox® bioassay. Here we describe a novel molecule-based assay system employing DNA as the chemical biosensor. Metals bind to DNA, causing structural changes that expel a bound (intercalated) fluorescent reporter dye. Analyses of test data using 48 wastewater samples potentially contaminated by metal ions show that the DNA-dye assay results correlate with those from C. dubia and Microtox bioassays. All three assays exhibit additive, antagonistic, and synergistic responses that cannot be predicted by knowing individual metal concentrations. Analyses of metals in these samples imply the presence of chemical toxicants other than metal ions. The DNA-dye assay is robust, has a 12-month shelf life, and is only slightly affected by sample pH in the range 4 to 9. The assay is completed in a matter of minutes, and its portability makes it well suited as a screening assay for use in the field. We conclude that the DNA-dye test is a surrogate bioassay suitable for screening chemical toxicity.
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Affiliation(s)
- Amy L Foreman
- The University of Sydney, Sydney, New South Wales, Australia
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dos Remedios CG, Robinson JE, Whan R, Braet F, Su Y, Kraft T, van der Velden J, Marston SB, Steenman M, Macdonald PS, Lal S. Spontaneous Oscillatory Contraction (SPOC): Quantifying the Contractile Performance of Human Cardiomyocytes. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.1828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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28
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Hoskins AC, Jacques A, Bardswell SC, McKenna WJ, Tsang V, dos Remedios CG, Ehler E, Adams K, Jalilzadeh S, Avkiran M, Watkins H, Redwood C, Marston SB, Kentish JC. Normal passive viscoelasticity but abnormal myofibrillar force generation in human hypertrophic cardiomyopathy. J Mol Cell Cardiol 2010; 49:737-45. [PMID: 20615414 PMCID: PMC2954357 DOI: 10.1016/j.yjmcc.2010.06.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/02/2010] [Accepted: 06/20/2010] [Indexed: 01/13/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy, increased ventricular stiffness and impaired diastolic filling. We investigated to what extent myocardial functional defects can be explained by alterations in the passive and active properties of human cardiac myofibrils. Skinned ventricular myocytes were prepared from patients with obstructive HCM (two patients with MYBPC3 mutations, one with a MYH7 mutation, and three with no mutation in either gene) and from four donors. Passive stiffness, viscous properties, and titin isoform expression were similar in HCM myocytes and donor myocytes. Maximal Ca2+-activated force was much lower in HCM myocytes (14 ± 1 kN/m2) than in donor myocytes (23 ± 3 kN/m2; P < 0.01), though cross-bridge kinetics (ktr) during maximal Ca2+ activation were 10% faster in HCM myocytes. Myofibrillar Ca2+ sensitivity in HCM myocytes (pCa50 = 6.40 ± 0.05) was higher than for donor myocytes (pCa50 = 6.09 ± 0.02; P < 0.001) and was associated with reduced phosphorylation of troponin-I (ser-23/24) and MyBP-C (ser-282) in HCM myocytes. These characteristics were common to all six HCM patients and may therefore represent a secondary consequence of the known and unknown underlying genetic variants. Some HCM patients did however exhibit an altered relationship between force and cross-bridge kinetics at submaximal Ca2+ concentrations, which may reflect the primary mutation. We conclude that the passive viscoelastic properties of the myocytes are unlikely to account for the increased stiffness of the HCM ventricle. However, the low maximum Ca2+-activated force and high Ca2+ sensitivity of the myofilaments are likely to contribute substantially to any systolic and diastolic dysfunction, respectively, in hearts of HCM patients.
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Affiliation(s)
- Anita C Hoskins
- Cardiovascular Division, King's College London British Heart Foundation Centre, London, UK
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Ho JWK, Lin MW, Adelstein S, dos Remedios CG. Erratum: Customising an antibody leukocyte capture microarray for systemic lupus erythematosus: Beyond biomarker discovery. Proteomics Clin Appl 2010. [DOI: 10.1002/prca.201090021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Kong SW, Hu YW, Ho JWK, Ikeda S, Polster S, John R, Hall JL, Bisping E, Pieske B, Remedios CGD, Pu WT. Heart failure-associated changes in RNA splicing of sarcomere genes. Circ Cardiovasc Genet 2010; 3:138-46. [PMID: 20124440 PMCID: PMC3073230 DOI: 10.1161/circgenetics.109.904698] [Citation(s) in RCA: 110] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Alternative mRNA splicing is an important mechanism for regulation of gene expression. Altered mRNA splicing occurs in association with several types of cancer, and a small number of disease-associated changes in splicing have been reported in heart disease. However, genome-wide approaches have not been used to study splicing changes in heart disease. We hypothesized that mRNA splicing is different in diseased hearts compared with control hearts. METHODS AND RESULTS We used the Affymetrix Exon array to globally evaluate mRNA splicing in left ventricular myocardial RNA from controls (n=15) and patients with ischemic cardiomyopathy (n=15). We observed a broad and significant decrease in mRNA splicing efficiency in heart failure, which affected some introns to a greater extent than others. The profile of mRNA splicing separately clustered ischemic cardiomyopathy and control samples, suggesting distinct changes in mRNA splicing between groups. Reverse transcription-polymerase chain reaction validated 9 previously unreported alternative splicing events. Furthermore, we demonstrated that splicing of 4 key sarcomere genes, cardiac troponin T (TNNT2), cardiac troponin I (TNNI3), myosin heavy chain 7 (MYH7), and filamin C, gamma (FLNC), was significantly altered in ischemic cardiomyopathy and in dilated cardiomyopathy and aortic stenosis. In aortic stenosis samples, these differences preceded the onset of heart failure. Remarkably, the ratio of minor to major splice variants of TNNT2, MYH7, and FLNC classified independent test samples as control or disease with >98% accuracy. CONCLUSIONS Our data indicate that mRNA splicing is broadly altered in human heart disease and that patterns of aberrant RNA splicing accurately assign samples to control or disease classes.
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Affiliation(s)
- Sek Won Kong
- Department of Cardiology, Children's Hospital Boston, 300 Longwood Ave., Boston, MA, USA
- Children's Hospital Informatics Program, 300 Longwood Ave., Boston, MA, USA
| | - Yong Wu Hu
- Department of Cardiology, Children's Hospital Boston, 300 Longwood Ave., Boston, MA, USA
- Department of Life Sciences, Wenzhou Medical College, Wenzhou, China
| | - Joshua W. K. Ho
- School of Information Technologies, The University of Sydney, and NICTA, Australian Technology Park, Sydney, New South Wales, Australia
| | - Sadakatsu Ikeda
- Department of Cardiology, Children's Hospital Boston, 300 Longwood Ave., Boston, MA, USA
| | - Sean Polster
- Lillehei Heart Institute, Department of Medicine and Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455
| | - Ranjit John
- Department of Surgery, University of Minnesota, Minneapolis, MN 55455
| | - Jennifer L. Hall
- Lillehei Heart Institute, Department of Medicine and Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455
| | - Egbert Bisping
- Department of Clinical Cardiology, Medical University of Graz, Auenbruggerplatz 15, Graz, Austria
| | - Burkert Pieske
- Department of Clinical Cardiology, Medical University of Graz, Auenbruggerplatz 15, Graz, Austria
| | | | - William T. Pu
- Department of Cardiology, Children's Hospital Boston, 300 Longwood Ave., Boston, MA, USA
- Harvard Stem Cell Institute, 42 Church Street, Cambridge, MA, USA
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Remedios CGD, Estigoy C, Cameron D, Ho J, Herbert B, Padula M, Pickford R, Guilhaus M, Odeberg J, Ponten F. Proteomics of the Human Cardiac Intercalated Disc: A More Complex Multi-Functional Structure than was Previously Thought. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.4148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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32
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Ho JWK, Stefani M, dos Remedios CG, Charleston MA. A model selection approach to discover age-dependent gene expression patterns using quantile regression models. BMC Genomics 2009; 10 Suppl 3:S16. [PMID: 19958479 PMCID: PMC2788368 DOI: 10.1186/1471-2164-10-s3-s16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background It has been a long-standing biological challenge to understand the molecular regulatory mechanisms behind mammalian ageing. Harnessing the availability of many ageing microarray datasets, a number of studies have shown that it is possible to identify genes that have age-dependent differential expression (DE) or differential variability (DV) patterns. The majority of the studies identify "interesting" genes using a linear regression approach, which is known to perform poorly in the presence of outliers or if the underlying age-dependent pattern is non-linear. Clearly a more robust and flexible approach is needed to identify genes with various age-dependent gene expression patterns. Results Here we present a novel model selection approach to discover genes with linear or non-linear age-dependent gene expression patterns from microarray data. To identify DE genes, our method fits three quantile regression models (constant, linear and piecewise linear models) to the expression profile of each gene, and selects the least complex model that best fits the available data. Similarly, DV genes are identified by fitting and comparing two quantile regression models (non-DV and the DV models) to the expression profile of each gene. We show that our approach is much more robust than the standard linear regression approach in discovering age-dependent patterns. We also applied our approach to analyze two human brain ageing datasets and found many biologically interesting gene expression patterns, including some very interesting DV patterns, that have been overlooked in the original studies. Furthermore, we propose that our model selection approach can be extended to discover DE and DV genes from microarray datasets with discrete class labels, by considering different quantile regression models. Conclusion In this paper, we present a novel application of quantile regression models to identify genes that have interesting linear or non-linear age-dependent expression patterns. One important contribution of this paper is to introduce a model selection approach to DE and DV gene identification, which is most commonly tackled by null hypothesis testing approaches. We show that our approach is robust in analyzing real and simulated datasets. We believe that our approach is applicable in many ageing or time-series data analysis tasks.
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Affiliation(s)
- Joshua W K Ho
- School of Information Technologies, The University of Sydney, NSW 2006, Australia.
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Ho JWK, Lin MW, Braet F, Su YY, Adelstein S, dos Remedios CG. Customising an antibody leukocyte capture microarray for systemic lupus erythematosus: beyond biomarker discovery. Proteomics Clin Appl 2009; 4:179-89. [PMID: 21137042 DOI: 10.1002/prca.200900165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2009] [Revised: 08/10/2009] [Accepted: 09/17/2009] [Indexed: 11/10/2022]
Abstract
Systemic lupus erythematosus (SLE) is a complex autoimmune disease that has heterogeneous clinical manifestation with diverse patterns of organ involvement, autoantibody profiles and varying degrees of severity of disease. Research and clinical experience indicate that different subtypes of SLE patients will likely benefit from more tailored treatment regimes, but we currently lack a fast and objective test with high enough sensitivity to enable us to perform such sub-grouping for clinical use. In this article, we review how proteomic technologies could be used as such an objective test. In particular, we extensively review many leukocyte surface markers that are known to have an association with the pathogenesis of SLE, and we discuss how these markers can be used in the further development of a novel SLE-specific antibody leukocyte capture microarray. In addition, we review some bioinformatics challenges and current methods for using the data generated by these cell-capture microarrays in clinical use. In a broader context, we hope our experience in developing a disease specific cell-capture microarray for clinical application can be a guide to other proteomic practitioners who intend to extend their technologies to develop clinical diagnostic and prognostic tests for complex diseases.
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Affiliation(s)
- Joshua W K Ho
- Muscle Research Unit, Bosch Institute, The University of Sydney, Sydney, NSW, Australia
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dos Remedios CG, Yamane M, Hughes J, Stefani M, Fukuda N, Kurihara S, Steenman M, Ishiwata S. SPOC: A Functional Assay of Failing and Non-Failing Human Cardiomyocytes. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.1941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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dos Remedios CG, Yamane M, Robinson J, Hughes J, Stefani M, Fukuda N, Kurihara S, Steenman M, Ishiwata S. Spontaneous Oscillatory Contraction: A Functional Assay of Contractile Function of Human Heart Samples Stored at −190°C. Heart Lung Circ 2009. [DOI: 10.1016/j.hlc.2009.05.476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
MOTIVATION Current microarray analyses focus on identifying sets of genes that are differentially expressed (DE) or differentially coexpressed (DC) in different biological states (e.g. diseased versus non-diseased). We observed that in many human diseases, some genes have a significant increase or decrease in expression variability (variance). As these observed changes in expression variability may be caused by alteration of the underlying expression dynamics, such differential variability (DV) patterns are also biologically interesting. RESULTS Here we propose a novel analysis for changes in gene expression variability between groups of samples, which we call differential variability analysis. We introduce the concept of differential variability (DV), and present a simple procedure for identifying DV genes from microarray data. Our procedure is evaluated with simulated and real microarray datasets. The effect of data preprocessing methods on identification of DV gene is investigated. The biological significance of DV analysis is demonstrated with four human disease datasets. The relationships among DV, DE and DC genes are investigated. The results suggest that changes in expression variability are associated with changes in coexpression pattern, which imply that DV is not merely stochastic noise, but informative signal. AVAILABILITY The R source code for differential variability analysis is available from the contact authors upon request.
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Affiliation(s)
- Joshua W K Ho
- School of Information Technologies, The University of Sydney, Sydney, NSW 2006, Australia.
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Lui R, Brown A, Wu B, Lin MW, Thompson J, Braet F, Dyer W, Lattimore J, Macdonald P, Adelstein S, dos Remedios CG. Use of Antibody Microarrays in the Analysis of Inflammation, Autoimmunity, Viral Infection, and Cancer Metastases. Clin Proteomics 2008. [DOI: 10.1002/9783527622153.ch31] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
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Ho JWK, Koundinya R, Caetano TS, dos Remedios CG, Charleston MA. Inferring differential leukocyte activity from antibody microarrays using a latent variable model. Genome Inform 2008; 21:126-137. [PMID: 19425153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Recent development of cluster of differentiation (CD) antibody arrays has enabled expression levels of many leukocyte surface CD antigens to be monitored simultaneously. Such membrane-proteome surveys have provided a powerful means to detect changes in leukocyte activity in various human diseases, such as cancer and cardiovascular diseases. The challenge is to devise a computational method to infer differential leukocyte activity among multiple biological states based on antigen expression profiles. Standard DNA microarray analysis methods cannot accurately infer differential leukocyte activity because they often fail to take the cell-to-antigen relationships into account. Here we present a novel latent variable model (LVM) approach to tackle this problem. The idea is to model each cell type as a latent variable, and represent the class-to-cell and cell-to-antigen relationships as a LVM. Once the parameters of the LVM are learned from the data, differentially active leukocytes can be easily identified from the model. We describe the model formulation and assumptions which lead to an efficient expectation-maximization algorithm. Our LVM method was applied to re-analyze two cardiovascular disease datasets. We show that our results match existing biological knowledge better than other methods such as gene set enrichment analysis. Furthermore, we discuss how our approach can be extended to become a general framework for gene set analysis for DNA microarrays.
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Affiliation(s)
- Joshua W K Ho
- School of Information Technologies, The University of Sydney, NSW, Australia.
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Nicolau DV, Solana G, Kekic M, Fulga F, Mahanivong C, Wright J, Ivanova EP, dos Remedios CG. Surface hydrophobicity modulates the operation of actomyosin-based dynamic nanodevices. Langmuir 2007; 23:10846-54. [PMID: 17854206 DOI: 10.1021/la700412m] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
We studied the impact of surface hydrophobicity on the motility of actin filaments moving on heavy-meromyosin (HMM)-coated surfaces. Apart from nitrocellulose (NC), which is the current standard for motility assays, all materials tested are good candidates for microfabrication: hydrophilic and hydrophobic glass, poly(methyl methacrylate) (PMMA), poly(tert-butyl methacrylate) (PtBuMA), and a copolymer of O-acryloyl acetophenone oxime with a 4-acryloyloxybenzophenone (AAPO). The most hydrophilic (hydrophilic glass, contact angle 35 degrees) and the most hydrophobic (PtBuMA, contact angle 78 degrees) surfaces do not maintain the motility of actin filaments, presumably because of the low density of adsorbed HMM protein or its high levels of denaturation, respectively. The velocity of actin filaments presents higher values in the middle of this "surface hydrophobicity motility window" (NC, PMMA), and a bimodal distribution, which is more apparent at the edges of this motility window (hydrophobic glass and AAPO). A molecular surface analysis of HMM and its S1 units suggests that the two very different, temporally separated conformations of the HMM heads could exacerbate the surface-modulated protein behavior, which is common to all microdevices using surface-immobilized proteins. An explanation for the above behavior proposes that the motility of actin filaments on HMM-functionalized surfaces is the result of the action of three populations of motors, each in a different surface-protein conformation, that is, HMM with both heads working (high velocities), working with one head (low velocities), and fully denatured HMM (no motility). It is also proposed that the molecularly dynamic nature of polymer surfaces amplifies the impact of surface hydrophobicity on protein behavior. The study demonstrates that PMMA is a good candidate for the fabrication of future actomyosin-driven dynamic nanodevices because it induces the smoothest motility of individual nano-objects with velocities comparable with those obtained on NC.
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Affiliation(s)
- Dan V Nicolau
- Department of Electrical Engineering and Electronics, The University of Liverpool, Liverpool, L69 3GJ, U.K
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Abstract
Observations of fast unfolding events in proteins are typically restricted to <100 degrees C. We use a novel apparatus to heat and cool enzymes within tens of nanoseconds to temperatures well in excess of the boiling point. The nanosecond temperature spikes are too fast to allow water to boil but can affect protein function. Spikes of 174 degrees C for catalase and approximately 290 degrees C for horseradish peroxidase are required to produce irreversible loss of enzyme activity. Similar temperature spikes have no effect when restricted to 100 degrees C or below. These results indicate that the "speed limit" for the thermal unfolding of large proteins is shorter than 10(-8) s. The unfolding rate at high temperature is consistent with extrapolation of low temperature rates over 12 orders of magnitude using the Arrhenius relation.
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Affiliation(s)
- Bradley C Steel
- School of Physics and Bosch Institute, The University of Sydney, Sydney, NSW 2006, Australia
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Chhabra D, Nosworthy NJ, dos Remedios CG. The N-terminal fragment of gelsolin inhibits the interaction of DNase I with isolated actin, but not with the cofilin-actin complex. Proteomics 2005; 5:3131-6. [PMID: 16021605 DOI: 10.1002/pmic.200401127] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Apoptosis is essential in embryonic development, clonal selection of cells of the immune system and in the prevention of cancer. Apoptotic cells display characteristic changes in morphology that precede the eventual fragmentation of nuclear DNA resulting in cell death. Current evidence implicates DNase I as responsible for hydrolysis of DNA during apoptosis. In vivo, it is likely that cytoplasmic actin binds and inhibits the enzymatic activity and nuclear translocation of DNase I and that disruption of the actin-DNase I complex results in activation of DNase I. In this report we demonstrate that the N-terminal fragment of gelsolin (N-gelsolin) disrupts the actin-DNase I interaction. This provides a molecular mechanism for the role of the N-gelsolin in regulating DNase I activity. We also show that cofilin stabilises the actin-DNase I complex by forming a ternary complex that prevents N-gelsolin from releasing DNase I from actin. We suggest that both cofilin and gelsolin are essential in modulating the release of DNase I from actin.
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Affiliation(s)
- Deepak Chhabra
- Muscle Research Unit, Institute for Biomedical Research, School of Medical Sciences, University of Sydney, NSW 2006, Australia
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Jiang L, Bardini M, Keogh A, dos Remedios CG, Burnstock G. P2X1 receptors are closely associated with connexin 43 in human ventricular myocardium. Int J Cardiol 2005; 98:291-7. [PMID: 15686781 DOI: 10.1016/j.ijcard.2003.11.036] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2003] [Revised: 11/12/2003] [Accepted: 11/17/2003] [Indexed: 11/23/2022]
Abstract
BACKGROUND It has been suggested that gap-junctional conductance between cardiomyocytes is regulated through a specific ligand-receptor interaction between ATP and connexins. In this study we examined the localization of P2X1 ionotropic receptors and their relation to connexin43 in gap junctions in human left ventricles. METHODS AND RESULTS Using immunohistochemistry, we detected P2X1 expression predominantly in the intercalated discs. Labelling of the P2X1 receptor and the gap junction protein connexin43 showed close association in some gap junctions, while in others the two proteins often appeared to be spatially discrete. Western blotting detected four major bands at 45, 60, 95 and 120 kDa in the protein extracts from human left ventricles corresponding to equivalent bands from rat vas deferens. The most prominent band in human left ventricles was at 95 kDa, possibly a dimer of the native P2X1 receptor, whereas in rat vas deferens it was at 60 kDa. After preincubation of the antibody with its epitope peptide, the 45 and 60 kDa bands almost disappeared and the 95 and 120 kDa bands were significantly attenuated. CONCLUSIONS P2X1 receptors in human myocardium are densely localized in gap junctions at intercalated discs between muscle cells. Close association of P2X1 receptors and connexin 43 occurred in some regions of some gap junctions, but in others they were spatially separate. Little difference in the pattern of distribution of P2X1 receptors was found in failing left ventricles of patients with dilated cardiomyopathy, although Western blots showed an enhancement of P2X1 receptor protein.
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Affiliation(s)
- Lele Jiang
- Institute for Biomedical Research, Department of Anatomy and Histology, the University of Sydney, NSW, 2006, Australia
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dos Remedios CG. The 32nd European Muscle Conference. J Muscle Res Cell Motil 2004; 25:3-5. [PMID: 15160482 DOI: 10.1023/b:jure.0000021404.15388.5f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Tsubakihara M, Williams NK, Keogh A, dos Remedios CG. Comparison of gene expression between left atria and left ventricles from non-diseased humans. Proteomics 2003; 4:261-70. [PMID: 14730688 DOI: 10.1002/pmic.200300539] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We examine the reliability and accuracy of gene array technology in analyzing differences in gene expression between human non-diseased left atrium and left ventricle. We have used cDNA gene arrays and validated those data by carefully designed quantitative real-time polymerase chain reaction (PCR). We have identified pitfalls using cDNA gene array technology based on comparisons with other gene array studies and with changes reported for the levels of expression of the genes corresponding to these cDNAs. The high error rate reported here underscores the cautionary comments reported by others in this field.
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Affiliation(s)
- Masako Tsubakihara
- Institute for Biomedical Research, University of Sydney, Sydney, Australia.
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Abstract
OBJECTIVES The signal transduction pathways mediating the progression to failure have been intensively studied in a variety of in vitro and in vivo animal models. Recently, acute activation of the Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) has been observed in the heart, but whether this is sustained in ischemic heart disease (IHD) or dilated cardiomyopathy (DCM) has not been previously addressed. METHODS We assessed the tyrosine phosphorylation of STAT1, 3, 5 and 6 in ventricular samples of explanted human hearts with IHD (n=11) and DCM (n=9) as an indication of STAT activation. Samples from normal donor hearts (n=9) acted as controls. In parallel, we also assessed protein expression and phosphorylation of three major families of mitogen-activated protein kinases (MAPKs); ERK, p38 MAPK and c-Jun NH(2)-terminal kinase (JNK). RESULTS All STAT isoforms were significantly phosphorylated in DCM. In contrast, only the phosphorylation of STATs 1 and 5 were significantly enhanced in IHD. Expression of total STAT protein remained unchanged. For the MAPKs, significant phosphorylation of p38(MAPK) was only observed in IHD. In contrast, there was no change in ERK or JNK activation despite abundant protein expression. CONCLUSIONS We have shown that different members of the STAT transcription factor family are chronically phosphorylated in the failing heart as a result of IHD (STAT1 and 5) or DCM (STAT1, 3, 5 and 6). In contrast, IHD but not DCM showed significant p38(MAPK) phosphorylation. Whilst the differences noted between IHD and DCM may reflect different initiating events, the common activation of STATs 1 and 5 suggests that these transcription factors may play a common role regulating the progression of heart failure.
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Affiliation(s)
- Dominic C H Ng
- Cell Signalling Laboratory, Biochemistry and Molecular Biology in the School of Biomedical and Chemical Sciences, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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Abstract
Protein arrays are now an attractive proposition as they can measure a diverse range of protein interactions not possible with traditional DNA arrays. Antibody arrays are a specific subset of this technology. Originally conceived as multi-analyte detectors, antibody arrays are now used in a wide variety of applications. For instance, the potential of this technology to diagnose human diseases, such as leukemia, breast cancer and, potentially, heart failure, has stimulated much interest. Furthermore, identification of new protein targets in particular disease states will prove to be an invaluable tool in drug discovery and development. Patient prognosis and treatment are also potential applications of the technology. Antibody arrays have proved to be dynamic in response to these broad range of possibilities. This review examines variations in antibody array design and discusses current and potential applications of this novel and interesting technology.
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Affiliation(s)
- Sean P Lal
- Institute for Biomedical Research, University of Sydney, Sydney 2006, Australia
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Abstract
Actin is the principal component of the cytoskeleton, a structure that can be disassembled and reassembled in a matter of seconds in vivo. The state of assembly of actin in vivo is primarily regulated by one or more actin binding proteins (ABPs). Typically, the actions of ABPs have been studied one by one, however, we propose that multiple ABPs, acting cooperatively, may be involved in the control of actin filament length. Cofilin and DNase I are two ABPs that have previously been demonstrated to form a ternary complex with actin in vitro. This is the first report to demonstrate their co-localisation in vivo, and differences in their distributions. Our observations strongly suggest a physiological role for higher order complexes of actin in regulation of cytoskeletal assembly during processes such as cell division.
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Steel BC, Bilek MM, McKenzie DR, dos Remedios CG. A technique for microsecond heating and cooling of a thin (submicron) biological sample. Eur Biophys J 2002; 31:378-82. [PMID: 12202914 DOI: 10.1007/s00249-002-0228-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2002] [Revised: 03/14/2002] [Accepted: 03/14/2002] [Indexed: 10/27/2022]
Abstract
Temperature excursions of short duration are useful in exploring the effects of stress on biological systems. Stress will affect the conformation of biological molecules such as proteins, which will lead to an effect on their function. The feasibility of generating such temperature excursions is demonstrated by solving the heat diffusion equation for an aqueous layer on a silicon wafer. The silicon is rapidly heated by a laser pulse and also acts as a heat sink to quench the temperature rise. An oxide layer was used to limit the maximum temperature attained by the sample. We show that exposures above a 50 degrees C benchmark can be confined to times less than 5 micros.
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Affiliation(s)
- Bradley C Steel
- School of Physics, University of Sydney, Sydney 2006, Australia.
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Court NW, dos Remedios CG, Cordell J, Bogoyevitch MA. Cardiac expression and subcellular localization of the p38 mitogen-activated protein kinase member, stress-activated protein kinase-3 (SAPK3). J Mol Cell Cardiol 2002; 34:413-26. [PMID: 11991731 DOI: 10.1006/jmcc.2001.1523] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite the interest in the roles that mitogen-activated protein kinases (MAPKs) play in the heart, the role of the different MAPK isoforms has been relatively poorly defined. A third isoform of p38 MAPK, known variously as stress-activated protein kinase-3 (SAPK3), p38- gamma or ERK6, has been previously shown to differ from p38- alpha/ beta both in its molecular weight and its lack of inhibition by the compound SB203580. We have generated monoclonal antibodies with specificity for SAPK3 demonstrated by immunoblot analysis, immunofluorescence studies, and cloning of SAPK3 from a rat heart cDNA expression library. By immunoblotting, we confirmed high expression of SAPK3 in fast, slow and mixed fibre types of murine skeletal muscle and observed significant expression restricted to heart, lung, thymus and testes. In addition to expression in normal heart (human, mouse, rat, dog and pig), we observed constant expression in diseased human heart, as well as control and hypertrophic cultured neonatal rat cardiac myocytes. Immunolocalization in cultured cardiac myocytes followed by confocal microscopy showed punctate, non-nuclear SAPK3 staining. In contrast, p38- alpha/ beta staining was non-punctate and distributed throughout the cytosol and nucleus. Whereas treatment with Leptomycin B to prevent nuclear export processes promoted higher levels of p38- alpha/ beta staining in cardiac myocyte nuclei, there was no apparent change in SAPK3 localization under these conditions. These differences between p38- alpha/ beta and SAPK3 probably reflect the specialized functions of SAPK3 and emphasize the need to evaluate SAPK3 upstream activators and downstream targets in the heart.
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Affiliation(s)
- Naomi W Court
- Department of Biochemistry, University of Western Australia, Crawley, Western Australia 6009, Australia
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Bains NPS, Gorbatyuk VY, Nosworthy NJ, Robson SA, Maciejewski MW, dos Remedios CG, King GF. Backbone and side-chain 1H, 15N, and 13C assignments for chick cofilin. J Biomol NMR 2002; 22:193-194. [PMID: 11885570 DOI: 10.1023/a:1014227808686] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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