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Multiparametric Mechanistic Profiling of Inotropic Drugs in Adult Human Primary Cardiomyocytes. Sci Rep 2020; 10:7692. [PMID: 32376974 PMCID: PMC7203129 DOI: 10.1038/s41598-020-64657-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 04/10/2020] [Indexed: 01/10/2023] Open
Abstract
Effects of non-cardiac drugs on cardiac contractility can lead to serious adverse events. Furthermore, programs aimed at treating heart failure have had limited success and this therapeutic area remains a major unmet medical need. The challenges in assessing drug effect on cardiac contractility point to the fundamental translational value of the current preclinical models. Therefore, we sought to develop an adult human primary cardiomyocyte contractility model that has the potential to provide a predictive preclinical approach for simultaneously predicting drug-induced inotropic effect (sarcomere shortening) and generating multi-parameter data to profile different mechanisms of action based on cluster analysis of a set of 12 contractility parameters. We report that 17 positive and 9 negative inotropes covering diverse mechanisms of action exerted concentration-dependent increases and decreases in sarcomere shortening, respectively. Interestingly, the multiparametric readout allowed for the differentiation of inotropes operating via distinct mechanisms. Hierarchical clustering of contractility transient parameters, coupled with principal component analysis, enabled the classification of subsets of both positive as well as negative inotropes, in a mechanism-related mode. Thus, human cardiomyocyte contractility model could accurately facilitate informed mechanistic-based decision making, risk management and discovery of molecules with the most desirable pharmacological profile for the correction of heart failure.
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Abi-Gerges N, Miller PE, Ghetti A. Human Heart Cardiomyocytes in Drug Discovery and Research: New Opportunities in Translational Sciences. Curr Pharm Biotechnol 2019; 21:787-806. [PMID: 31820682 DOI: 10.2174/1389201021666191210142023] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/14/2019] [Accepted: 10/28/2019] [Indexed: 12/28/2022]
Abstract
In preclinical drug development, accurate prediction of drug effects on the human heart is critically important, whether in the context of cardiovascular safety or for the purpose of modulating cardiac function to treat heart disease. Current strategies have significant limitations, whereby, cardiotoxic drugs can escape detection or potential life-saving therapies are abandoned due to false positive toxicity signals. Thus, new and more reliable translational approaches are urgently needed to help accelerate the rate of new therapy development. Renewed efforts in the recovery of human donor hearts for research and in cardiomyocyte isolation methods, are providing new opportunities for preclinical studies in adult primary cardiomyocytes. These cells exhibit the native physiological and pharmacological properties, overcoming the limitations presented by artificial cellular models, animal models and have great potential for providing an excellent tool for preclinical drug testing. Adult human primary cardiomyocytes have already shown utility in assessing drug-induced cardiotoxicity risk and helping in the identification of new treatments for cardiac diseases, such as heart failure and atrial fibrillation. Finally, strategies with actionable decision-making trees that rely on data derived from adult human primary cardiomyocytes will provide the holistic insights necessary to accurately predict human heart effects of drugs.
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Affiliation(s)
- Najah Abi-Gerges
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
| | - Paul E Miller
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
| | - Andre Ghetti
- AnaBios Corporation, 3030 Bunker Hill St., Suite 312, San Diego, CA 92109, United States
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Yeh CC, Fan Y, Xu Y, Yang YL, Simpson PC, Mann MJ. Shift toward greater pathologic post-myocardial infarction remodeling with loss of the adaptive hypertrophic signaling of alpha1 adrenergic receptors in mice. PLoS One 2017; 12:e0188471. [PMID: 29216197 PMCID: PMC5720786 DOI: 10.1371/journal.pone.0188471] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 11/07/2017] [Indexed: 11/18/2022] Open
Abstract
Rationale We have hypothesized that post-infarction cardiac remodeling can be influenced by shifts in the balance between intracellular mediators of “pathologic” and “physiologic” hypertrophy. Although alpha1 adrenergic receptors (alpha1-ARs) mediate pro-adaptive hypertrophy during pressure overload, little is known about their role or downstream mediators after myocardial infarction. Methods We performed loss-of-function experiments via coronary ligation in alpha1A-AR knockout (AKO) mice. Post-myocardial infarction (MI) remodeling was evaluated via echocardiography, quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis of cardiac fetal gene expression, histologic analysis of myocyte size, post-MI fibrosis and apoptosis, and Western blot analysis of apoptotic regulators. Results Alpha1A-AR knockout paradoxically increased post-MI hypertrophy compared to wild type controls (WT), but also increased ventricular dilatation, fibrosis, apoptosis, and 4-week post-MI mortality (64% in AKO vs. 25% in WT, P = 0.02), suggesting a shift toward greater pathologic hypertrophy in the absence of pro-adaptive alpha1A effects. alpha1A-AR knockout increased phospho-p38 levels in the pre-MI myocardium compared to WT (0.55 ± 0.16 vs. 0.03 ± 0.01, P<0.05) but decreased phospho-ERK1/2 post-MI (0.49 ± 0.35 arbitrary units vs. 1.55 ± 0.43 in WT, P<0.05). Furthermore, expression of pro-apoptotic factor Bax was increased (1.19 ± 0.15 vs. 0.78 ± 0.08, P<0.05) and expression of anti-apoptotic factors Bcl2 was decreased (0.26 ± 0.01 vs. 0.55 ± 0.06, P<0.01) compared to WT. Conclusions Alpha1A-AR provides an important counterbalance to pathologic pathways during post-MI remodeling that may be mediated through ERK1/2 signaling; these observations provide support for further development of an alpha1A-AR/ERK-based molecular intervention for this chronic, often fatal disease.
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Affiliation(s)
- Che-Chung Yeh
- Cardiothoracic Translational Research Laboratory, University of California San Francisco, San Francisco, California, United States of America
| | - Yanying Fan
- Cardiothoracic Translational Research Laboratory, University of California San Francisco, San Francisco, California, United States of America
| | - Yanchun Xu
- Cardiothoracic Translational Research Laboratory, University of California San Francisco, San Francisco, California, United States of America
| | - Yi-Lin Yang
- Cardiothoracic Translational Research Laboratory, University of California San Francisco, San Francisco, California, United States of America
| | - Paul C. Simpson
- Division of Cardiology, Veterans Affairs Medical Center and University of California San Francisco, San Francisco, California, United States of America
| | - Michael J. Mann
- Cardiothoracic Translational Research Laboratory, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Myagmar BE, Flynn JM, Cowley PM, Swigart PM, Montgomery MD, Thai K, Nair D, Gupta R, Deng DX, Hosoda C, Melov S, Baker AJ, Simpson PC. Adrenergic Receptors in Individual Ventricular Myocytes: The Beta-1 and Alpha-1B Are in All Cells, the Alpha-1A Is in a Subpopulation, and the Beta-2 and Beta-3 Are Mostly Absent. Circ Res 2017; 120:1103-1115. [PMID: 28219977 DOI: 10.1161/circresaha.117.310520] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 02/13/2017] [Accepted: 02/17/2017] [Indexed: 12/20/2022]
Abstract
RATIONALE It is unknown whether every ventricular myocyte expresses all 5 of the cardiac adrenergic receptors (ARs), β1, β2, β3, α1A, and α1B. The β1 and β2 are thought to be the dominant myocyte ARs. OBJECTIVE Quantify the 5 cardiac ARs in individual ventricular myocytes. METHODS AND RESULTS We studied ventricular myocytes from wild-type mice, mice with α1A and α1B knockin reporters, and β1 and β2 knockout mice. Using individual isolated cells, we measured knockin reporters, mRNAs, signaling (phosphorylation of extracellular signal-regulated kinase and phospholamban), and contraction. We found that the β1 and α1B were present in all myocytes. The α1A was present in 60%, with high levels in 20%. The β2 and β3 were detected in only ≈5% of myocytes, mostly in different cells. In intact heart, 30% of total β-ARs were β2 and 20% were β3, both mainly in nonmyocytes. CONCLUSION The dominant ventricular myocyte ARs present in all cells are the β1 and α1B. The β2 and β3 are mostly absent in myocytes but are abundant in nonmyocytes. The α1A is in just over half of cells, but only 20% have high levels. Four distinct myocyte AR phenotypes are defined: 30% of cells with β1 and α1B only; 60% that also have the α1A; and 5% each that also have the β2 or β3. The results raise cautions in experimental design, such as receptor overexpression in myocytes that do not express the AR normally. The data suggest new paradigms in cardiac adrenergic signaling mechanisms.
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Affiliation(s)
- Bat-Erdene Myagmar
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - James M Flynn
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Patrick M Cowley
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Philip M Swigart
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Megan D Montgomery
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Kevin Thai
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Divya Nair
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Rumita Gupta
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - David X Deng
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Chihiro Hosoda
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Simon Melov
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Anthony J Baker
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.)
| | - Paul C Simpson
- From the Department of Medicine, VA Medical Center, San Francisco, CA (B.-E.M., P.M.C., P.M.S., M.D.M., K.T., D.N., R.G., D.X.D., C.H., A.J.B., P.C.S.); Department of Medicine and Cardiovascular Research Institute, University of California, San Francisco (B.-E.M., P.M.C., M.D.M., D.X.D., C.H., A.J.B., P.C.S.); and Buck Institute for Research on Aging, Novato, CA (J.M.F., S.M.).
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Cowley PM, Wang G, Chang AN, Makwana O, Swigart PM, Lovett DH, Stull JT, Simpson PC, Baker AJ. The α1A-adrenergic receptor subtype mediates increased contraction of failing right ventricular myocardium. Am J Physiol Heart Circ Physiol 2015; 309:H888-96. [PMID: 26116709 DOI: 10.1152/ajpheart.00042.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 06/24/2015] [Indexed: 12/23/2022]
Abstract
Dysfunction of the right ventricle (RV) is closely related to prognosis for patients with RV failure. Therefore, strategies to improve failing RV function are significant. In a mouse RV failure model, we previously reported that α1-adrenergic receptor (α1-AR) inotropic responses are increased. The present study determined the roles of both predominant cardiac α1-AR subtypes (α1A and α1B) in upregulated inotropy in failing RV. We used the mouse model of bleomycin-induced pulmonary fibrosis, pulmonary hypertension, and RV failure. We assessed the myocardial contractile response in vitro to stimulation of the α1A-subtype (using α1A-subtype-selective agonist A61603) and α1B-subtype [using α1A-subtype knockout mice and nonsubtype selective α1-AR agonist phenylephrine (PE)]. In wild-type nonfailing RV, a negative inotropic effect of α1-AR stimulation with PE (force decreased ≈50%) was switched to a positive inotropic effect (PIE) with bleomycin-induced RV injury. Upregulated inotropy in failing RV occurred with α1A-subtype stimulation (force increased ≈200%), but not with α1B-subtype stimulation (force decreased ≈50%). Upregulated inotropy mediated by the α1A-subtype involved increased activator Ca(2+) transients and increased phosphorylation of myosin regulatory light chain (a mediator of increased myofilament Ca(2+) sensitivity). In failing RV, the PIE elicited by the α1A-subtype was appreciably less when the α1A-subtype was stimulated in combination with the α1B-subtype, suggesting functional antagonism between α1A- and α1B-subtypes. In conclusion, upregulation of α1-AR inotropy in failing RV myocardium requires the α1A-subtype and is opposed by the α1B-subtype. The α1A subtype might be a therapeutic target to improve the function of the failing RV.
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Affiliation(s)
- Patrick M Cowley
- Veterans Affairs Medical Center, San Francisco, and Department of Medicine, University California San Francisco, San Francisco, California; and
| | - Guanying Wang
- Veterans Affairs Medical Center, San Francisco, and Department of Medicine, University California San Francisco, San Francisco, California; and
| | - Audrey N Chang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Om Makwana
- Veterans Affairs Medical Center, San Francisco, and Department of Medicine, University California San Francisco, San Francisco, California; and
| | - Philip M Swigart
- Veterans Affairs Medical Center, San Francisco, and Department of Medicine, University California San Francisco, San Francisco, California; and
| | - David H Lovett
- Veterans Affairs Medical Center, San Francisco, and Department of Medicine, University California San Francisco, San Francisco, California; and
| | - James T Stull
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Paul C Simpson
- Veterans Affairs Medical Center, San Francisco, and Department of Medicine, University California San Francisco, San Francisco, California; and
| | - Anthony J Baker
- Veterans Affairs Medical Center, San Francisco, and Department of Medicine, University California San Francisco, San Francisco, California; and
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Alpha-1-adrenergic receptors in heart failure: the adaptive arm of the cardiac response to chronic catecholamine stimulation. J Cardiovasc Pharmacol 2014; 63:291-301. [PMID: 24145181 DOI: 10.1097/fjc.0000000000000032] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Alpha-1-adrenergic receptors (ARs) are G protein-coupled receptors activated by catecholamines. The alpha-1A and alpha-1B subtypes are expressed in mouse and human myocardium, whereas the alpha-1D protein is found only in coronary arteries. There are far fewer alpha-1-ARs than beta-ARs in the nonfailing heart, but their abundance is maintained or increased in the setting of heart failure, which is characterized by pronounced chronic elevation of catecholamines and beta-AR dysfunction. Decades of evidence from gain and loss-of-function studies in isolated cardiac myocytes and numerous animal models demonstrate important adaptive functions for cardiac alpha-1-ARs to include physiological hypertrophy, positive inotropy, ischemic preconditioning, and protection from cell death. Clinical trial data indicate that blocking alpha-1-ARs is associated with incident heart failure in patients with hypertension. Collectively, these findings suggest that alpha-1-AR activation might mitigate the well-recognized toxic effects of beta-ARs in the hyperadrenergic setting of chronic heart failure. Thus, exogenous cardioselective activation of alpha-1-ARs might represent a novel and viable approach to the treatment of heart failure.
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Wu SC, Dahl EF, Wright CD, Cypher AL, Healy CL, O'Connell TD. Nuclear localization of a1A-adrenergic receptors is required for signaling in cardiac myocytes: an “inside-out” a1-AR signaling pathway. J Am Heart Assoc 2014; 3:e000145. [PMID: 24772522 PMCID: PMC4187477 DOI: 10.1161/jaha.113.000145] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Background Recent studies indicate that α1‐adrenergic receptors (α1‐ARs) are cardioprotective by preventing cardiac myocyte death and augmenting contractility in heart failure. Although G‐protein‐coupled receptors are assumed to localize to and signal at the plasma membrane, we previously demonstrated that endogenous α1‐ARs localize to the nuclei in adult cardiac myocytes. However, the functional consequence of this nuclear localization remains unclear. Here, we attempted to reconcile nuclear localization of α1‐ARs with their physiologic function by examining α1‐AR‐induced contractility in adult cardiac myocytes. Methods and Results By measuring shortening in unloaded, cultured adult cardiac myocytes, we found that the α1A‐subtype regulated contractility through phosphorylation of cardiac troponin I (cTnI) at the protein kinase C (PKC) site, threonine 144. Reconstitution of an α1A‐subtype nuclear localization mutant in cardiac myocytes lacking α1‐ARs failed to rescue nuclear α1A‐mediated phosphorylation of cTnI and myocyte contractility. Leptomycin B, the nuclear export inhibitor, also blocked α1A‐mediated phosphorylation of cTnI. These data indicate that α1‐AR signaling originates in the nucleus. Consistent with these observations, we localized the α1A‐subtype to the inner nuclear membrane, identified PKCα, δ, and ε in the nucleus, and found that α1‐ARs activate PKCδ in nuclei isolated from adult cardiac myocytes. Finally, we found that a PKCδ nuclear localization mutant blunted α1‐induced phosphorylation of cTnI. Conclusions Together, our data identify a novel, “inside‐out” nuclear α1A‐subtype/PKCδ/cTnI‐signaling pathway that regulates contractile function in adult cardiac myocytes. Importantly, these data help resolve the discrepancy between nuclear localization of α1‐ARs and α1‐AR‐mediated physiologic function.
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Affiliation(s)
- Steven C. Wu
- Department of Integrative Biology and Physiology, The University of Minnesota, Minneapolis, MN (S.C.W., E.F.D., C.D.W., A.L.C., C.L.H., T.D.C.)
| | - Erika F. Dahl
- Department of Integrative Biology and Physiology, The University of Minnesota, Minneapolis, MN (S.C.W., E.F.D., C.D.W., A.L.C., C.L.H., T.D.C.)
| | - Casey D. Wright
- Department of Integrative Biology and Physiology, The University of Minnesota, Minneapolis, MN (S.C.W., E.F.D., C.D.W., A.L.C., C.L.H., T.D.C.)
- Novartis Animal Health US, Inc, 1447140th St, Larchwood, IA 51241
| | - Andrew L. Cypher
- Department of Integrative Biology and Physiology, The University of Minnesota, Minneapolis, MN (S.C.W., E.F.D., C.D.W., A.L.C., C.L.H., T.D.C.)
- Novartis Animal Health US, Inc, 1447140th St, Larchwood, IA 51241
| | - Chastity L. Healy
- Department of Integrative Biology and Physiology, The University of Minnesota, Minneapolis, MN (S.C.W., E.F.D., C.D.W., A.L.C., C.L.H., T.D.C.)
| | - Timothy D. O'Connell
- Department of Integrative Biology and Physiology, The University of Minnesota, Minneapolis, MN (S.C.W., E.F.D., C.D.W., A.L.C., C.L.H., T.D.C.)
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9
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Milani-Nejad N, Janssen PML. Small and large animal models in cardiac contraction research: advantages and disadvantages. Pharmacol Ther 2014; 141:235-49. [PMID: 24140081 PMCID: PMC3947198 DOI: 10.1016/j.pharmthera.2013.10.007] [Citation(s) in RCA: 308] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Accepted: 08/15/2013] [Indexed: 12/22/2022]
Abstract
The mammalian heart is responsible for not only pumping blood throughout the body but also adjusting this pumping activity quickly depending upon sudden changes in the metabolic demands of the body. For the most part, the human heart is capable of performing its duties without complications; however, throughout many decades of use, at some point this system encounters problems. Research into the heart's activities during healthy states and during adverse impacts that occur in disease states is necessary in order to strategize novel treatment options to ultimately prolong and improve patients' lives. Animal models are an important aspect of cardiac research where a variety of cardiac processes and therapeutic targets can be studied. However, there are differences between the heart of a human being and an animal and depending on the specific animal, these differences can become more pronounced and in certain cases limiting. There is no ideal animal model available for cardiac research, the use of each animal model is accompanied with its own set of advantages and disadvantages. In this review, we will discuss these advantages and disadvantages of commonly used laboratory animals including mouse, rat, rabbit, canine, swine, and sheep. Since the goal of cardiac research is to enhance our understanding of human health and disease and help improve clinical outcomes, we will also discuss the role of human cardiac tissue in cardiac research. This review will focus on the cardiac ventricular contractile and relaxation kinetics of humans and animal models in order to illustrate these differences.
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Affiliation(s)
- Nima Milani-Nejad
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology and D. Davis Heart Lung Institute, College of Medicine, The Ohio State University, OH, USA.
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Bhat HF, Adams ME, Khanday FA. Syntrophin proteins as Santa Claus: role(s) in cell signal transduction. Cell Mol Life Sci 2013; 70:2533-54. [PMID: 23263165 PMCID: PMC11113789 DOI: 10.1007/s00018-012-1233-9] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2012] [Revised: 11/21/2012] [Accepted: 12/03/2012] [Indexed: 11/30/2022]
Abstract
Syntrophins are a family of cytoplasmic membrane-associated adaptor proteins, characterized by the presence of a unique domain organization comprised of a C-terminal syntrophin unique (SU) domain and an N-terminal pleckstrin homology (PH) domain that is split by insertion of a PDZ domain. Syntrophins have been recognized as an important component of many signaling events, and they seem to function more like the cell's own personal 'Santa Claus' that serves to 'gift' various signaling complexes with precise proteins that they 'wish for', and at the same time care enough for the spatial, temporal control of these signaling events, maintaining overall smooth functioning and general happiness of the cell. Syntrophins not only associate various ion channels and signaling proteins to the dystrophin-associated protein complex (DAPC), via a direct interaction with dystrophin protein but also serve as a link between the extracellular matrix and the intracellular downstream targets and cell cytoskeleton by interacting with F-actin. They play an important role in regulating the postsynaptic signal transduction, sarcolemmal localization of nNOS, EphA4 signaling at the neuromuscular junction, and G-protein mediated signaling. In our previous work, we reported a differential expression pattern of alpha-1-syntrophin (SNTA1) protein in esophageal and breast carcinomas. Implicated in several other pathologies, like cardiac dys-functioning, muscular dystrophies, diabetes, etc., these proteins provide a lot of scope for further studies. The present review focuses on the role of syntrophins in membrane targeting and regulation of cellular proteins, while highlighting their relevance in possible development and/or progression of pathologies including cancer which we have recently demonstrated.
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Affiliation(s)
- Hina F Bhat
- Department of Biotechnology, University of Kashmir, Srinagar, Jammu and Kashmir, India.
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11
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Chu C, Thai K, Park KW, Wang P, Makwana O, Lovett DH, Simpson PC, Baker AJ. Intraventricular and interventricular cellular heterogeneity of inotropic responses to α(1)-adrenergic stimulation. Am J Physiol Heart Circ Physiol 2013; 304:H946-53. [PMID: 23355341 DOI: 10.1152/ajpheart.00822.2012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
α1-Adrenergic receptors (α1-ARs) elicit a negative inotropic effect (NIE) in the mouse right ventricular (RV) myocardium but a positive inotropic effect (PIE) in the left ventricular (LV) myocardium. Effects on myofilament Ca(2+) sensitivity play a role, but effects on Ca(2+) handling could also contribute. We monitored the effects of α1-AR stimulation on contraction and Ca(2+) transients using single myocytes isolated from the RV or LV. Interestingly, for both the RV and LV, we found heterogeneous myocyte inotropic responses. α1-ARs mediated either a PIE or NIE, although RV myocytes had a greater proportion of cells manifesting a NIE (68%) compared with LV myocytes (36%). Stimulation of a single α1-AR subtype (α1A-ARs) with a subtype-selective agonist also elicited heterogeneous inotropic responses, suggesting that the heterogeneity arose from events downstream of the α1A-AR subtype. For RV and LV myocytes, an α1-AR-mediated PIE was associated with an increased Ca(2+) transient and a NIE was associated with a decreased Ca(2+) transient, suggesting a key role for Ca(2+) handling. For RV and LV myocytes, α1-AR-mediated decreases in the Ca(2+) transient were associated with increased Ca(2+) export from the cell and decreased Ca(2+) content of the sarcoplasmic reticulum. In contrast, for myocytes with α1-AR-induced increased Ca(2+) transients, sarcoplasmic reticulum Ca(2+) content was not increased, suggesting that other mechanisms contributed to the increased Ca(2+) transients. This study demonstrates the marked heterogeneity of LV and RV cellular inotropic responses to stimulation of α1-ARs and reveals a new aspect of biological heterogeneity among myocytes in the regulation of contraction.
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Affiliation(s)
- Charles Chu
- Veterans Affairs Medical Center, San Francisco, CA 94121, USA
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12
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Jensen BC, O'Connell TD, Simpson PC. Alpha-1-adrenergic receptors: targets for agonist drugs to treat heart failure. J Mol Cell Cardiol 2010; 51:518-28. [PMID: 21118696 DOI: 10.1016/j.yjmcc.2010.11.014] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 11/12/2010] [Indexed: 12/19/2022]
Abstract
Evidence from cell, animal, and human studies demonstrates that α1-adrenergic receptors mediate adaptive and protective effects in the heart. These effects may be particularly important in chronic heart failure, when catecholamine levels are elevated and β-adrenergic receptors are down-regulated and dysfunctional. This review summarizes these data and proposes that selectively activating α1-adrenergic receptors in the heart might represent a novel and effective way to treat heart failure. This article is part of a special issue entitled "Key Signaling Molecules in Hypertrophy and Heart Failure."
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Affiliation(s)
- Brian C Jensen
- Cardiology Division, VA Medical Center, San Francisco, CA, USA.
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13
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Tsang S, Wong SSC, Wu S, Kravtsov GM, Wong TM. Testosterone-augmented contractile responses to α1- and β1-adrenoceptor stimulation are associated with increased activities of RyR, SERCA, and NCX in the heart. Am J Physiol Cell Physiol 2009; 296:C766-82. [DOI: 10.1152/ajpcell.00193.2008] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We hypothesized that testosterone at physiological levels enhances cardiac contractile responses to stimulation of both α1- and β1-adrenoceptors by increasing Ca2+ release from the sarcoplasmic reticulum (SR) and speedier removal of Ca2+ from cytosol via Ca2+-regulatory proteins. We first determined the left ventricular developed pressure, velocity of contraction and relaxation, and heart rate in perfused hearts isolated from control rats, orchiectomized rats, and orchiectomized rats without and with testosterone replacement (200 μg/100 g body wt) in the presence of norepinephrine (10−7 M), the α1-adrenoceptor agonist phenylephrine (10−6 M), or the nonselective β-adrenoceptor agonist isoprenaline (10−7 M) in the presence of 5 × 10−7 M ICI-118,551, a β2-adrenoceptor antagonist. Next, we determined the amplitudes of intracellular Ca2+ concentration transients induced by electrical stimulation or caffeine, which represent, respectively, Ca2+ release via the ryanodine receptor (RyR) or releasable Ca2+ in the SR, in ventricular myocytes isolated from the three groups of rats. We also measured 45Ca2+ release via the RyR. We then determined the time to 50% decay of both transients, which represents, respectively, Ca2+ reuptake by sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) and removal via the sarcolemmal Na+/Ca2+ exchanger (NCX). We correlated Ca2+ removal from the cytosol with activities of SERCA and its regulator phospholamban as well as NCX. The results showed that testosterone at physiological levels enhanced positive inotropic and lusitropic responses to stimulation of α1- and β1-adrenoceptors via the androgen receptor. The increased contractility and speedier relaxation were associated with increased Ca2+ release via the RyR and faster Ca2+ removal out of the cytosol via SERCA and NCX.
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14
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Mechanisms of α1-adrenoceptor mediated QT prolongation in the diabetic rat heart. Life Sci 2009; 84:250-6. [DOI: 10.1016/j.lfs.2008.12.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Revised: 11/14/2008] [Accepted: 12/06/2008] [Indexed: 11/23/2022]
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15
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Lyssand JS, DeFino MC, Tang XB, Hertz AL, Feller DB, Wacker JL, Adams ME, Hague C. Blood pressure is regulated by an alpha1D-adrenergic receptor/dystrophin signalosome. J Biol Chem 2008; 283:18792-800. [PMID: 18468998 DOI: 10.1074/jbc.m801860200] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hypertension is a cardiovascular disease associated with increased plasma catecholamines, overactivation of the sympathetic nervous system, and increased vascular tone and total peripheral resistance. A key regulator of sympathetic nervous system function is the alpha(1D)-adrenergic receptor (AR), which belongs to the adrenergic family of G-protein-coupled receptors (GPCRs). Endogenous catecholamines norepinephrine and epinephrine activate alpha(1D)-ARs on vascular smooth muscle to stimulate vasoconstriction, which increases total peripheral resistance and mean arterial pressure. Indeed, alpha(1D)-AR KO mice display a hypotensive phenotype and are resistant to salt-induced hypertension. Unfortunately, little information exists about how this important GPCR functions because of an inability to obtain functional expression in vitro. Here, we identified the dystrophin proteins, syntrophin, dystrobrevin, and utrophin as essential GPCR-interacting proteins for alpha(1D)-ARs. We found that dystrophins complex with alpha(1D)-AR both in vitro and in vivo to ensure proper functional expression. More importantly, we demonstrate that knock-out of multiple syntrophin isoforms results in the complete loss of alpha(1D)-AR function in mouse aortic smooth muscle cells and abrogation of alpha(1D)-AR-mediated increases in blood pressure. Our findings demonstrate that syntrophin and utrophin associate with alpha(1D)-ARs to create a functional signalosome, which is essential for alpha(1D)-AR regulation of vascular tone and blood pressure.
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Affiliation(s)
- John S Lyssand
- Department of Pharmacology, University of Washington, Seattle, Washington 98195, USA
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16
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McCloskey DT, Turcato S, Wang GY, Turnbull L, Zhu BQ, Bambino T, Nguyen AP, Lovett DH, Nissenson RA, Karliner JS, Baker AJ. Expression of a Gi-coupled receptor in the heart causes impaired Ca2+ handling, myofilament injury, and dilated cardiomyopathy. Am J Physiol Heart Circ Physiol 2007; 294:H205-12. [PMID: 17965283 DOI: 10.1152/ajpheart.00829.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Increased signaling by G(i)-coupled receptors has been implicated in dilated cardiomyopathy. To investigate the mechanisms, we used transgenic mice that develop dilated cardiomyopathy after conditional expression of a cardiac-targeted G(i)-coupled receptor (Ro1). Activation of G(i) signaling by the Ro1 agonist spiradoline caused decreased cellular cAMP levels and bradycardia in Langendorff-perfused hearts. However, acute termination of Ro1 signaling with the antagonist nor-binaltorphimine did not reverse the Ro1-induced contractile dysfunction, indicating that Ro1 cardiomyopathy was not due to acute effects of receptor signaling. Early after initiation of Ro1 expression, there was a 40% reduction in the abundance of the sarcoplasmic reticulum Ca(2+)-ATPase (P < 0.05); thereafter, there was progressive impairment of both Ca(2+) handling and force development assessed with ventricular trabeculae. Six weeks after initiation of Ro1 expression, systolic Ca(2+) concentration was reduced to 0.61 +/- 0.08 vs. 0.91 +/- 0.07 microM for control (n = 6-8; P < 0.05), diastolic Ca(2+) concentration was elevated to 0.41 +/- 0.07 vs. 0.23 +/- 0.06 microM for control (n = 6-8; P < 0.01), and the decline phase of the Ca(2+) transient (time from peak to 50% decline) was slowed to 0.25 +/- 0.02 s vs. 0.13 +/- 0.02 s for control (n = 6-8; P < 0.01). Early after initiation of Ro1 expression, there was a ninefold elevation of matrix metalloproteinase-2 (P < 0.01), which is known to cause myofilament injury. Consistent with this, 6 wk after initiation of Ro1 expression, Ca(2+)-saturated myofilament force in skinned trabeculae was reduced to 21 +/- 2 vs. 38 +/- 0.1 mN/mm(2) for controls (n = 3; P < 0.01). Furthermore, electron micrographs revealed extensive myofilament damage. These findings may have implications for some forms of human heart failure in which increased activity of G(i)-coupled receptors leads to impaired Ca(2+) handling and myofilament injury, contributing to impaired ventricular pump function and heart failure.
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Affiliation(s)
- Diana T McCloskey
- VA Medical Center, Cardiology Division (111C ), University of California-San Francisco, 4150 Clement St., San Francisco, CA 94121, USA
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17
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Wang GY, McCloskey DT, Turcato S, Swigart PM, Simpson PC, Baker AJ. Contrasting inotropic responses to α1-adrenergic receptor stimulation in left versus right ventricular myocardium. Am J Physiol Heart Circ Physiol 2006; 291:H2013-7. [PMID: 16731650 DOI: 10.1152/ajpheart.00167.2006] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The left ventricle (LV) and right ventricle (RV) have differing hemodynamics and embryological origins, but it is unclear whether they are regulated differently. In particular, no previous studies have directly compared the LV versus RV myocardial inotropic responses to α1-adrenergic receptor (α1-AR) stimulation. We compared α1-AR inotropy of cardiac trabeculae from the LV versus RV of adult mouse hearts. As previously reported, for mouse RV trabeculae, α1-AR stimulation with phenylephrine (PE) caused a triphasic contractile response with overall negative inotropy. In marked contrast, LV trabeculae had an overall positive inotropic response to PE. Stimulation of a single subtype (α1A-AR) with A-61603 also mediated contrasting LV/RV inotropy, suggesting differential activation of multiple α1-AR-subtypes was not involved. Contrasting LV/RV α1-AR inotropy was not abolished by inhibiting protein kinase C, suggesting differential activation of PKC isoforms was not involved. However, contrasting LV/RV α1-AR inotropic responses did involve different effects on myofilament Ca2+ sensitivity: submaximal force of skinned trabeculae was increased by PE pretreatment for LV but was decreased by PE for RV. For LV myocardium, α1-AR-induced net positive inotropy was abolished by the myosin light chain kinase inhibitor ML-9. This study suggests that LV and RV myocardium have fundamentally different inotropic responses to α1-AR stimulation, involving different effects on myofilament function and myosin light chain phosphorylation.
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Affiliation(s)
- Guan-Ying Wang
- VA Medical Center, Cardiology Division (111C 4150 Clement St., San Francisco, CA 94121, USA
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18
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Hirano S, Kusakari Y, O-Uchi J, Morimoto S, Kawai M, Hongo K, Kurihara S. Intracellular mechanism of the negative inotropic effect induced by alpha1-adrenoceptor stimulation in mouse myocardium. J Physiol Sci 2006; 56:297-304. [PMID: 16884559 DOI: 10.2170/physiolsci.rp007306] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2006] [Accepted: 08/02/2006] [Indexed: 11/05/2022]
Abstract
Alpha(1)-adrenoceptor stimulation (alpha(1)ARS) shows a positive inotropic effect in most mammalian myocardium. In mouse myocardium, however, alpha(1)ARS showed the negative inotropic effect, of which intracellular mechanisms are not fully clarified. The purpose of this study is to investigate the intracellular mechanism of the negative inotropic effect by alpha(1)ARS in C57BL/6 mouse myocardium. We used isolated ventricular papillary muscles of C57BL/6 strain mouse which is widely used for genetic manipulation. We simultaneously measured isometric tension and intracellular Ca(2+) concentration ([Ca(2+)](i)) using the aequorin method. In twitch contraction, phenylephrine concentration-dependently (1-100 microM) decreased tension without significant changes in the Ca(2+) transient, and these effects were completely blocked by prazosin (3 microM) or calphostin C (a PKC inhibitor, 1 microM). Phorbol 12-myristate 13-acetate (PMA) (a PKC activator, 1 microM) decreased tension as observed in phenylephrine. After PMA application, the negative inotropic effect of phenylephrine disappeared. To estimate the Ca(2+) sensitivity, tetanic contraction was produced, and the relation between [Ca(2+)](i) and tension at a steady state was measured. Phenylephrine (10 microM) decreased the Ca(2+) sensitivity, and PMA showed a similar Ca(2+) desensitizing effect. These results suggest that the negative inotropic effect of phenylephrine in mouse myocardium can be explained by the decrease in the Ca(2+) sensitivity through the activation of PKC. The present result indicates that the effect of alpha(1)ARS differs among species and strains of experiment animals. Thus, we should be careful about using the results of mouse myocardium to understand the functions of the human heart.
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Affiliation(s)
- Shuta Hirano
- Department of Physiology II, The Jikei University School of Medicine, Minato-ku, Tokyo, 105-8461, Japan
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19
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McCloskey DT, Turnbull L, Swigart PM, Zambon AC, Turcato S, Joho S, Grossman W, Conklin BR, Simpson PC, Baker AJ. Cardiac transgenesis with the tetracycline transactivator changes myocardial function and gene expression. Physiol Genomics 2005; 22:118-26. [PMID: 15797971 DOI: 10.1152/physiolgenomics.00016.2005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The cardiac-specific tetracycline-regulated gene expression system (tet-system) is a powerful tool using double-transgenic mice. The cardiac alpha-myosin heavy chain promoter (alphaMHC) drives lifetime expression of a tetracycline-inhibited transcription activator (tTA). Crossing alphaMHC-tTA mice with mice containing a tTA-responsive promoter linked to a target gene yields double-transgenic mice having tetracycline-repressed expression of the target gene in the heart. Using the tet-system, some studies use nontransgenic mice for the control group, whereas others use single-transgenic alphaMHC-tTA mice. However, previous studies found that high-level expression of a modified activator protein caused cardiomyopathy. Therefore, we tested whether cardiac expression of tTA was associated with altered function of alphaMHC-tTA mice compared with wild-type (WT) littermates. We monitored in vivo and in vitro function and gene expression profiles for myocardium from WT and alphaMHC-tTA mice. Compared with WT littermates, alphaMHC-tTA mice had a greater heart-to-body weight ratio (approximately 10%), ventricular dilation, and decreased ejection fraction, suggesting mild cardiomyopathy. In vitro, submaximal contractions were greater compared with WT and were associated with greater myofilament Ca2+ sensitivity. Gene expression profiling revealed that the expression of 153 genes was significantly changed by >20% when comparing alphaMHC-tTA with WT myocardium. These findings demonstrate that introduction of the alphaMHC-tTA construct causes significant effects on myocardial gene expression and major functional abnormalities in vivo and in vitro. For studies using the tet-system, these results suggest caution in the use of controls, since alphaMHC-tTA myocardium differs appreciably from WT. Furthermore, the results raise the possibility that the phenotype conferred by a target gene may be influenced by the modified genetic background of alphaMHC-tTA myocardium.
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Affiliation(s)
- Diana T McCloskey
- Department of Radiology, University of California, San Francisco, USA
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20
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Varma DR, Rindt H, Chemtob S, Mulay S. Mechanism of the negative inotropic effects of alpha 1-adrenoceptor agonists on mouse myocardium. Can J Physiol Pharmacol 2003; 81:783-9. [PMID: 12897807 DOI: 10.1139/y03-071] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
This study was done to identify the mechanism of the alpha1-adrenoceptor (AR) mediated negative inotropic effects of phenylephrine (PE) on adult mouse myocardium. As reported by others, we also found that the nonselective alpha1AR agonist PE produced a negative inotropic effect on ventricular strips from adult mice that was inhibited by the alpha1AAR antagonist 5-methylurapidil (5MU) but not by the alpha1BAR antagonist chloroethylclonidine (CEC) or the alpha1DAR antagonist BMY 7378. The selective alpha1AAR agonist A61603 also produced a negative inotropic effect, which was antagonized by 5MU. Phorbol 12,13-dibutyrate (activator of all PKC isoforms) mimicked the negative inotropic responses to PE and A61603. The negative inotropic effects of PE were inhibited by bisindolylmaleimide (inhibitor of all PKC isoforms) but not by Gö 6976 (inhibitor of Ca2+-dependent PKC). Rottlerin, an inhibitor of Ca2+-independent PKCdelta, antagonized the negative inotropic effects of PE and A61603. PE and A61603 increased the translocation of PKCdelta, which was prevented by rottlerin. These data suggest that the alpha1AR-mediated negative inotropy on adult mouse myocardium is signaled by Ca2+-independent PKCdelta.
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Affiliation(s)
- Daya R Varma
- Department of Pharmacology and Theraputics, McGill University, Montréal, QC H3G 1Y6, Canada.
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21
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O'Connell TD, Ishizaka S, Nakamura A, Swigart PM, Rodrigo MC, Simpson GL, Cotecchia S, Rokosh DG, Grossman W, Foster E, Simpson PC. The alpha(1A/C)- and alpha(1B)-adrenergic receptors are required for physiological cardiac hypertrophy in the double-knockout mouse. J Clin Invest 2003; 111:1783-91. [PMID: 12782680 PMCID: PMC156101 DOI: 10.1172/jci16100] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Catecholamines and alpha(1)-adrenergic receptors (alpha(1)-ARs) cause cardiac hypertrophy in cultured myocytes and transgenic mice, but heart size is normal in single KOs of the main alpha(1)-AR subtypes, alpha(1A/C) and alpha(1B). Here we tested whether alpha(1)-ARs are required for developmental cardiac hypertrophy by generating alpha(1A/C) and alpha(1B) double KO (ABKO) mice, which had no cardiac alpha(1)-AR binding. In male ABKO mice, heart growth after weaning was 40% less than in WT, and the smaller heart was due to smaller myocytes. Body and other organ weights were unchanged, indicating a specific effect on the heart. Blood pressure in ABKO mice was the same as in WT, showing that the smaller heart was not due to decreased load. Contractile function was normal by echocardiography in awake mice, but the smaller heart and a slower heart rate reduced cardiac output. alpha(1)-AR stimulation did not activate extracellular signal-regulated kinase (Erk) and downstream kinases in ABKO myocytes, and basal Erk activity was lower in the intact ABKO heart. In female ABKO mice, heart size was normal, even after ovariectomy. Male ABKO mice had reduced exercise capacity and increased mortality with pressure overload. Thus, alpha(1)-ARs in male mice are required for the physiological hypertrophy of normal postnatal cardiac development and for an adaptive response to cardiac stress.
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MESH Headings
- Animals
- Blotting, Western
- Body Weight
- Cells, Cultured
- Dose-Response Relationship, Drug
- Echocardiography
- Female
- Genotype
- Heart/physiology
- Hypertrophy/genetics
- MAP Kinase Signaling System
- Male
- Mice
- Mice, Knockout
- Mice, Transgenic
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/metabolism
- Muscle Cells/metabolism
- Myocardial Contraction
- Myocardium/metabolism
- Organ Size
- Physical Conditioning, Animal
- Receptors, Adrenergic, alpha-1/genetics
- Receptors, Adrenergic, alpha-1/physiology
- Ribonucleases/metabolism
- Sex Factors
- Time Factors
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Affiliation(s)
- Timothy D O'Connell
- San Francisco Veterans Affairs Medical Center, Department of Medicine, University of California San Francisco (UCSF), San Francisco, California 94121, USA
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22
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O’Connell TD, Ishizaka S, Nakamura A, Swigart PM, Rodrigo M, Simpson GL, Cotecchia S, Rokosh DG, Grossman W, Foster E, Simpson PC. The α1A/C- and α1B-adrenergic receptors are required for physiological cardiac hypertrophy in the double-knockout mouse. J Clin Invest 2003. [DOI: 10.1172/jci200316100] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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23
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Turnbull L, McCloskey DT, O'Connell TD, Simpson PC, Baker AJ. Alpha 1-adrenergic receptor responses in alpha 1AB-AR knockout mouse hearts suggest the presence of alpha 1D-AR. Am J Physiol Heart Circ Physiol 2003; 284:H1104-9. [PMID: 12595294 DOI: 10.1152/ajpheart.00441.2002] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two functional alpha(1)-adrenergic receptor (AR) subtypes (alpha(1A) and alpha(1B)) have been identified in the mouse heart. However, it is unclear whether the third known subtype, alpha(1D)-AR, is also present. To investigate this, we determined whether there were alpha(1)-AR responses in hearts from a novel mouse model lacking alpha(1A)- and alpha(1B)-ARs (double knockout) (ABKO). In Langendorff-perfused hearts, alpha(1)-ARs were stimulated with phenylephrine. For ABKO hearts, phenylephrine reduced left ventricular pressure and coronary flow (to 87 +/- 2% and 86 +/- 4% of initial, respectively, n = 11, P < 0.01). These effects were blocked by prazosin and 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]-8-azaspirol[4,5]decane-7,9-dione] dihydrochloride, suggesting that alpha(1D)-AR-mediated responses were present. In contrast, right ventricular trabeculae from ABKO hearts did not respond to phenylephrine, suggesting that in ABKO perfused hearts, the effects of phenylephrine were not mediated by direct actions on cardiomyocytes. A novel finding was that alpha(1)-AR stimulation caused positive inotropy in the wild-type mouse heart, in contrast to negative inotropy observed in mouse cardiac muscle strips. We conclude that mouse hearts lacking alpha(1A)- and alpha(1B)-ARs retain functional alpha(1)-AR responses involving decreases of coronary flow and ventricular pressure that reflect alpha(1D)-AR-mediated vasoconstriction. Furthermore, alpha(1)-AR inotropic responses depend critically on the experimental conditions.
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Affiliation(s)
- Lynne Turnbull
- Department of Medicine and Cardiovascular Research Institute, University of California and Veterans Affairs Medical Center, San Francisco, USA
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24
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Steinberg SF. Alpha(1)-adrenergic receptor subtype function in cardiomyocytes: lessons from genetic models in mice. J Mol Cell Cardiol 2002; 34:1141-5. [PMID: 12392888 DOI: 10.1006/jmcc.2002.2057] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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