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Ohiri JC, Dellefave‐Castillo L, Tomar G, Wilsbacher L, Choudhury L, Barefield DY, Fullenkamp D, Gacita AM, Monroe TO, Pesce L, Blancard M, Vaught L, George AL, Demonbreun AR, Puckelwartz MJ, McNally EM. Reduction of Filamin C Results in Altered Proteostasis, Cardiomyopathy, and Arrhythmias. J Am Heart Assoc 2024; 13:e030467. [PMID: 38761081 PMCID: PMC11179814 DOI: 10.1161/jaha.123.030467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 04/17/2024] [Indexed: 05/20/2024]
Abstract
BACKGROUND Many cardiomyopathy-associated FLNC pathogenic variants are heterozygous truncations, and FLNC pathogenic variants are associated with arrhythmias. Arrhythmia triggers in filaminopathy are incompletely understood. METHODS AND RESULTS We describe an individual with biallelic FLNC pathogenic variants, p.Arg650X and c.970-4A>G, with peripartum cardiomyopathy and ventricular arrhythmias. We also describe clinical findings in probands with FLNC variants including Val2715fs87X, Glu2458Serfs71X, Phe106Leu, and c.970-4A>G with hypertrophic and dilated cardiomyopathy, atrial fibrillation, and ventricular tachycardia. Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were generated. The FLNC truncation, Arg650X/c.970-4A>G, showed a marked reduction in filamin C protein consistent with biallelic loss of function mutations. To assess loss of filamin C, gene editing of a healthy control iPSC line was used to generate a homozygous FLNC disruption in the actin binding domain. Because filamin C has been linked to protein quality control, we assessed the necessity of filamin C in iPSC-CMs for response to the proteasome inhibitor bortezomib. After exposure to low-dose bortezomib, FLNC-null iPSC-CMs showed an increase in the chaperone proteins BAG3, HSP70 (heat shock protein 70), and HSPB8 (small heat shock protein B8) and in the autophagy marker LC3I/II. FLNC null iPSC-CMs had prolonged electric field potential, which was further prolonged in the presence of low-dose bortezomib. FLNC null engineered heart tissues had impaired function after low-dose bortezomib. CONCLUSIONS FLNC pathogenic variants associate with a predisposition to arrhythmias, which can be modeled in iPSC-CMs. Reduction of filamin C prolonged field potential, a surrogate for action potential, and with bortezomib-induced proteasome inhibition, reduced filamin C led to greater arrhythmia potential and impaired function.
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Affiliation(s)
- Joyce C. Ohiri
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | | | - Garima Tomar
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Lisa Wilsbacher
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Lubna Choudhury
- Bluhm Cardiovascular InstituteNorthwestern MedicineChicagoILUSA
| | - David Y. Barefield
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
- Cell and Molecular PhysiologyLoyola University Stritch School of MedicineMaywoodILUSA
| | - Dominic Fullenkamp
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Anthony M. Gacita
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Tanner O. Monroe
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Lorenzo Pesce
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Malorie Blancard
- Department of Pharmacology, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Lauren Vaught
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Alfred L. George
- Department of Pharmacology, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Alexis R. Demonbreun
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
- Department of Pharmacology, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Megan J. Puckelwartz
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
- Department of Pharmacology, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of MedicineNorthwestern UniversityChicagoILUSA
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Chabanovska O, Lemcke H, Lang H, Vollmar B, Dohmen PM, David R, Etz C, Neßelmann C. Sarcomeric network analysis of ex vivo cultivated human atrial appendage tissue using super-resolution microscopy. Sci Rep 2023; 13:13041. [PMID: 37563225 PMCID: PMC10415305 DOI: 10.1038/s41598-023-39962-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 08/02/2023] [Indexed: 08/12/2023] Open
Abstract
Investigating native human cardiac tissue with preserved 3D macro- and microarchitecture is fundamental for clinical and basic research. Unfortunately, the low accessibility of the human myocardium continues to limit scientific progress. To overcome this issue, utilizing atrial appendages of the human heart may become highly beneficial. Atrial appendages are often removed during open-heart surgery and can be preserved ex vivo as living tissue with varying durability depending on the culture method. In this study, we prepared living thin myocardial slices from left atrial appendages that were cultured using an air-liquid interface system for overall 10 days. Metabolic activity of the cultured slices was assessed using a conventional methyl thiazolyl tetrazolium (MTT) assay. To monitor the structural integrity of cardiomyocytes within the tissue, we implemented our recently described super-resolution microscopy approach that allows both qualitative and quantitative in-depth evaluation of sarcomere network based on parameters such as overall sarcomere content, filament size and orientation. Additionally, expression of mRNAs coding for key structural and functional proteins was analyzed by real-time reverse transcription polymerase chain reaction (qRT-PCR). Our findings demonstrate highly significant disassembly of contractile apparatus represented by degradation of [Formula: see text]-actinin filaments detected after three days in culture, while metabolic activity was constantly rising and remained high for up to seven days. However, gene expression of crucial cardiac markers strongly decreased after the first day in culture indicating an early destructive response to ex vivo conditions. Therefore, we suggest static cultivation of living myocardial slices derived from left atrial appendage and prepared according to our protocol only for short-termed experiments (e.g. medicinal drug testing), while introduction of electro-mechanical stimulation protocols may offer the possibility for long-term integrity of such constructs.
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Affiliation(s)
- Oleksandra Chabanovska
- Reference and Translation Center for Cardiac Stem Cell therapy (RTC), Department of Cardiac Surgery, Rostock University Medical Center, 18057, Rostock, Germany
- Department of Life, Light, and Matter of the Interdisciplinary Faculty, Rostock University, 18059, Rostock, Germany
- Department of Operative Dentistry and Periodontology, Rostock University Medical Center, 18059, Rostock, Germany
| | - Heiko Lemcke
- Reference and Translation Center for Cardiac Stem Cell therapy (RTC), Department of Cardiac Surgery, Rostock University Medical Center, 18057, Rostock, Germany
- Department of Life, Light, and Matter of the Interdisciplinary Faculty, Rostock University, 18059, Rostock, Germany
| | - Hermann Lang
- Department of Operative Dentistry and Periodontology, Rostock University Medical Center, 18059, Rostock, Germany
| | - Brigitte Vollmar
- Rudolf-Zenker-Institute of Experimental Surgery, Rostock University Medical Center, 18059, Rostock, Germany
| | - Pascal M Dohmen
- Department of Cardiac Surgery, Rostock University Medical Center, 18059, Rostock, Germany
- Department of Cardiothoracic Surgery, Faculty of Health Science, University of the Free State, Bloemfontein, 9301, South Africa
| | - Robert David
- Reference and Translation Center for Cardiac Stem Cell therapy (RTC), Department of Cardiac Surgery, Rostock University Medical Center, 18057, Rostock, Germany.
- Department of Life, Light, and Matter of the Interdisciplinary Faculty, Rostock University, 18059, Rostock, Germany.
| | - Christian Etz
- Department of Cardiac Surgery, Rostock University Medical Center, 18059, Rostock, Germany
| | - Catharina Neßelmann
- Department of Cardiac Surgery, Rostock University Medical Center, 18059, Rostock, Germany
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3
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Ghosh R, Gillaspie JJ, Campbell KS, Symons JD, Boudina S, Pattison JS. Chaperone-mediated autophagy protects cardiomyocytes against hypoxic-cell death. Am J Physiol Cell Physiol 2022; 323:C1555-C1575. [PMID: 35584327 PMCID: PMC9829466 DOI: 10.1152/ajpcell.00369.2021] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 05/02/2022] [Accepted: 05/16/2022] [Indexed: 01/22/2023]
Abstract
Chaperone-mediated autophagy (CMA) is a chaperone-dependent process of selective cytosolic protein turnover that targets specific proteins to lysosomes for degradation. Enhancing protein degradation mechanisms has been shown to be beneficial in multiple models of cardiac disease, including myocardial infarction (MI) and ischemia-reperfusion (I/R) injury. However, the causal role of CMA in cardiomyocyte injury and death is largely unknown. Hypoxia is an important contributor to both MI and I/R damage, which are major, precedent causes of heart failure. Upregulating CMA was hypothesized to protect against hypoxia-induced cardiomyocyte death. Lysosome-associated membrane protein 2a (Lamp2a) overexpression and knockdown were used to causally study CMA's role in hypoxically stressed cardiomyocytes. LAMP2a protein levels were used as both a primary indicator and driver of CMA function. Hypoxic stress was stimulated by CoCl2 treatment, which increased LAMP2a protein levels (+1.4-fold) and induced cardiomyocyte apoptosis (+3.2-4.0-fold). Lamp2a siRNA knockdown (-3.2-fold) of control cardiomyocytes increased apoptosis (+1.8-fold) suggesting that loss of CMA is detrimental for cardiomyocyte survival. However, there was neither an additive nor a synergistic effect on cell death when Lamp2a-silenced cells were treated with CoCl2. Conversely, Lamp2a overexpression (+3.0-fold) successfully reduced hypoxia-induced apoptosis by ∼50%. LAMP2a was also significantly increased (+1.7-fold) in ischemic heart failure patient samples, similar to hypoxically stressed cardiomyocytes. The failing ischemic hearts may have had insufficient CMA activation. To our knowledge, this study for the first time establishes a protective role for CMA (via Lamp2a overexpression) against hypoxia-induced cardiomyocyte loss and reveals the intriguing possibility that CMA activation may offer a cardioprotective treatment for ischemic heart disease.
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Affiliation(s)
- Rajeshwary Ghosh
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
- Department of Nutrition and Integrative Physiology Program in Molecular Medicine, University of Utah, Salt Lake City, Utah
| | - Jennifer Jason Gillaspie
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
| | - Kenneth S Campbell
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky
| | - J David Symons
- Department of Nutrition and Integrative Physiology Program in Molecular Medicine, University of Utah, Salt Lake City, Utah
| | - Sihem Boudina
- Department of Nutrition and Integrative Physiology Program in Molecular Medicine, University of Utah, Salt Lake City, Utah
| | - James Scott Pattison
- Division of Basic Biomedical Sciences, Sanford School of Medicine, University of South Dakota, Vermillion, South Dakota
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Zhang J, Liang Y, Bradford WH, Sheikh F. Desmosomes: emerging pathways and non-canonical functions in cardiac arrhythmias and disease. Biophys Rev 2021; 13:697-706. [PMID: 34765046 PMCID: PMC8555023 DOI: 10.1007/s12551-021-00829-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 08/12/2021] [Indexed: 12/14/2022] Open
Abstract
Desmosomes are critical adhesion structures in cardiomyocytes, with mutation/loss linked to the heritable cardiac disease, arrhythmogenic right ventricular cardiomyopathy (ARVC). Early studies revealed the ability of desmosomal protein loss to trigger ARVC disease features including structural remodeling, arrhythmias, and inflammation; however, the precise mechanisms contributing to diverse disease presentations are not fully understood. Recent mechanistic studies demonstrated the protein degradation component CSN6 is a resident cardiac desmosomal protein which selectively restricts cardiomyocyte desmosomal degradation and disease. This suggests defects in protein degradation can trigger the structural remodeling underlying ARVC. Additionally, a subset of ARVC-related mutations show enhanced vulnerability to calpain-mediated degradation, further supporting the relevance of these mechanisms in disease. Desmosomal gene mutations/loss has been shown to impact arrhythmogenic pathways in the absence of structural disease within ARVC patients and model systems. Studies have shown the involvement of connexins, calcium handling machinery, and sodium channels as early drivers of arrhythmias, suggesting these may be distinct pathways regulating electrical function from the desmosome. Emerging evidence has suggested inflammation may be an early mechanism in disease pathogenesis, as clinical reports have shown an overlap between myocarditis and ARVC. Recent studies focus on the association between desmosomal mutations/loss and inflammatory processes including autoantibodies and signaling pathways as a way to understand the involvement of inflammation in ARVC pathogenesis. A specific focus will be to dissect ongoing fields of investigation to highlight diverse pathogenic pathways associated with desmosomal mutations/loss.
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Affiliation(s)
- Jing Zhang
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
| | - Yan Liang
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
| | - William H. Bradford
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
| | - Farah Sheikh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093 USA
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5
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Adewale AO, Ahn YH. Titin N2A Domain and Its Interactions at the Sarcomere. Int J Mol Sci 2021; 22:ijms22147563. [PMID: 34299183 PMCID: PMC8305307 DOI: 10.3390/ijms22147563] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/16/2022] Open
Abstract
Titin is a giant protein in the sarcomere that plays an essential role in muscle contraction with actin and myosin filaments. However, its utility goes beyond mechanical functions, extending to versatile and complex roles in sarcomere organization and maintenance, passive force, mechanosensing, and signaling. Titin’s multiple functions are in part attributed to its large size and modular structures that interact with a myriad of protein partners. Among titin’s domains, the N2A element is one of titin’s unique segments that contributes to titin’s functions in compliance, contraction, structural stability, and signaling via protein–protein interactions with actin filament, chaperones, stress-sensing proteins, and proteases. Considering the significance of N2A, this review highlights structural conformations of N2A, its predisposition for protein–protein interactions, and its multiple interacting protein partners that allow the modulation of titin’s biological effects. Lastly, the nature of N2A for interactions with chaperones and proteases is included, presenting it as an important node that impacts titin’s structural and functional integrity.
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6
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Liu H, Lee SM, Joung H. 2-D08 treatment regulates C2C12 myoblast proliferation and differentiation via the Erk1/2 and proteasome signaling pathways. J Muscle Res Cell Motil 2021; 42:193-202. [PMID: 34142311 PMCID: PMC8332585 DOI: 10.1007/s10974-021-09605-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 06/09/2021] [Indexed: 11/24/2022]
Abstract
SUMOylation is one of the post-translational modifications that involves the covalent attachment of the small ubiquitin-like modifier (SUMO) to the substrate. SUMOylation regulates multiple biological processes, including myoblast proliferation, differentiation, and apoptosis. 2-D08 is a synthetically available flavone, which acts as a potent cell-permeable SUMOylation inhibitor. Its mechanism of action involves preventing the transfer of SUMO from the E2 thioester to the substrate without influencing SUMO-activating enzyme E1 (SAE-1/2) or E2 Ubc9-SUMO thioester formation. However, both the effects and mechanisms of 2-D08 on C2C12 myoblast cells remain unclear. In the present study, we found that treatment with 2-D08 inhibits C2C12 cell proliferation and differentiation. We confirmed that 2-D08 significantly hampers the viability of C2C12 cells. Additionally, it inhibited myogenic differentiation, decreasing myosin heavy chain (MHC), MyoD, and myogenin expression. Furthermore, we confirmed that 2-D08-mediated anti-myogenic effects impair myoblast differentiation and myotube formation, reducing the number of MHC-positive C2C12 cells. In addition, we found that 2-D08 induces the activation of ErK1/2 and the degradation of MyoD and myogenin in C2C12 cells. Taken together, these results indicated that 2-D08 treatment results in the deregulated proliferation and differentiation of myoblasts. However, further research is needed to investigate the long-term effects of 2-D08 on skeletal muscles.
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Affiliation(s)
- Hyunju Liu
- Department of Obstetrics and Gynecology, Chosun University College of Medicine, Gwangju, Republic of Korea
| | - Su-Mi Lee
- Research Institute of Medical Sciences, Chonnam National University Medical School, Hwasun, Republic of Korea. .,Department of Internal Medicine, Division of Gastroenterology and Hepatology, Chonnam National University Medical School,, 42, Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea.
| | - Hosouk Joung
- Research Institute of Medical Sciences, Chonnam National University Medical School, Hwasun, Republic of Korea. .,Department of Internal Medicine, Division of Gastroenterology and Hepatology, Chonnam National University Medical School,, 42, Jebong-ro, Dong-gu, Gwangju, 61469, Republic of Korea.
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7
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The Role of HECT-Type E3 Ligase in the Development of Cardiac Disease. Int J Mol Sci 2021; 22:ijms22116065. [PMID: 34199773 PMCID: PMC8199989 DOI: 10.3390/ijms22116065] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 05/26/2021] [Accepted: 06/01/2021] [Indexed: 12/12/2022] Open
Abstract
Despite advances in medicine, cardiac disease remains an increasing health problem associated with a high mortality rate. Maladaptive cardiac remodeling, such as cardiac hypertrophy and fibrosis, is a risk factor for heart failure; therefore, it is critical to identify new therapeutic targets. Failing heart is reported to be associated with hyper-ubiquitylation and impairment of the ubiquitin–proteasome system, indicating an importance of ubiquitylation in the development of cardiac disease. Ubiquitylation is a post-translational modification that plays a pivotal role in protein function and degradation. In 1995, homologous to E6AP C-terminus (HECT) type E3 ligases were discovered. E3 ligases are key enzymes in ubiquitylation and are classified into three families: really interesting new genes (RING), HECT, and RING-between-RINGs (RBRs). Moreover, 28 HECT-type E3 ligases have been identified in human beings. It is well conserved in evolution and is characterized by the direct attachment of ubiquitin to substrates. HECT-type E3 ligase is reported to be involved in a wide range of human diseases and health. The role of HECT-type E3 ligases in the development of cardiac diseases has been uncovered in the last decade. There are only a few review articles summarizing recent advancements regarding HECT-type E3 ligase in the field of cardiac disease. This study focused on cardiac remodeling and described the role of HECT-type E3 ligases in the development of cardiac disease. Moreover, this study revealed that the current knowledge could be exploited for the development of new clinical therapies.
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8
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Liang Y, Lyon RC, Pellman J, Bradford WH, Lange S, Bogomolovas J, Dalton ND, Gu Y, Bobar M, Lee MH, Iwakuma T, Nigam V, Asimaki A, Scheinman M, Peterson KL, Sheikh F. Desmosomal COP9 regulates proteome degradation in arrhythmogenic right ventricular dysplasia/cardiomyopathy. J Clin Invest 2021; 131:137689. [PMID: 33857019 PMCID: PMC8159691 DOI: 10.1172/jci137689] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 04/14/2021] [Indexed: 12/28/2022] Open
Abstract
Dysregulated protein degradative pathways are increasingly recognized as mediators of human disease. This mechanism may have particular relevance to desmosomal proteins that play critical structural roles in both tissue architecture and cell-cell communication, as destabilization/breakdown of the desmosomal proteome is a hallmark of genetic-based desmosomal-targeted diseases, such as the cardiac disease arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). However, no information exists on whether there are resident proteins that regulate desmosomal proteome homeostasis. Here, we uncovered a cardiac constitutive photomorphogenesis 9 (COP9) desmosomal resident protein complex, composed of subunit 6 of the COP9 signalosome (CSN6), that enzymatically restricted neddylation and targeted desmosomal proteome degradation. CSN6 binding, localization, levels, and function were affected in hearts of classic mouse and human models of ARVD/C affected by desmosomal loss and mutations, respectively. Loss of desmosomal proteome degradation control due to junctional reduction/loss of CSN6 and human desmosomal mutations destabilizing junctional CSN6 were also sufficient to trigger ARVD/C in mice. We identified a desmosomal resident regulatory complex that restricted desmosomal proteome degradation and disease.
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Affiliation(s)
- Yan Liang
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Robert C. Lyon
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Jason Pellman
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - William H. Bradford
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Stephan Lange
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Institute of Medicine, Department of Molecular and Clinical Medicine and Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Gothenburg, Sweden
| | - Julius Bogomolovas
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Nancy D. Dalton
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Yusu Gu
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Marcus Bobar
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Mong-Hong Lee
- Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Tomoo Iwakuma
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Vishal Nigam
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
- Department of Pediatrics, Seattle Children’s Research Institute and University of Washington, Seattle, Washington, USA
| | - Angeliki Asimaki
- Cardiology Clinical Academic Group, St. George’s University of London, London, United Kingdom
| | - Melvin Scheinman
- Department of Medicine, Cardiac Electrophysiology Section, University of California San Francisco, San Francisco, California, USA
| | - Kirk L. Peterson
- Department of Medicine, University of California San Diego, La Jolla, California, USA
| | - Farah Sheikh
- Department of Medicine, University of California San Diego, La Jolla, California, USA
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9
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Park SG, Kim EK, Nam KH, Lee JG, Baek IJ, Lee BJ, Nam SY. Heart defects and embryonic lethality in Asb2 knock out mice correlate with placental defects. Cells Dev 2021; 165:203663. [PMID: 33993984 DOI: 10.1016/j.cdev.2021.203663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 01/03/2021] [Accepted: 01/25/2021] [Indexed: 10/22/2022]
Abstract
Asb2, ankyrin repeat, and SOCS box protein 2 form an E3 ubiquitin ligase complex. Asb2 ubiquitin ligase activity drives the degradation of filamins, which have essential functions in humans. The placenta is a temporary organ that forms during pregnancy, and normal placentation is important for survival and growth of the fetus. Recent studies have shown that approximately 25-30% of knockout (KO) mice have non-viable offspring, and 68% of knockout lines exhibit placental dysmorphologies. There are very few studies on Asb2, with insufficient research on its role in placental development. Therefore, we generated Asb2 knockout mice and undertook to investigate Asb2 expression during organogenesis, and to identify its role in early embryonic and placental development. The external morphology of KO embryos revealed abnormal phenotypes including growth retardation, pericardial effusion, pale color, and especially heart beat defect from E 9.5. Furthermore, Asb2 expression was observed in the heart from E 9.5, indicating that it is specifically expressed during early heart formation, resulting in embryonic lethality. Histological analysis of E 10.5 KO heart showed malformations such as failure of chamber formation, reduction in trabeculated myocardium length, absence of mesenchymal cells, and destruction of myocardium wall. Moreover, the histological results of Asb2-deficient placenta showed abnormal phenotypes including small labyrinth and reduced vascular complexity, indicating that failure to establish mature circulatory pattern affects the embryonic development and results in early mortality. Collectively, our results demonstrate that Asb2 knockout mice have placental defects, that subsequently result in failure to form a normal cardiac septum, and thereby result in embryo mortality in utero at around E 9.5.
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Affiliation(s)
- Seul Gi Park
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Eun-Kyoung Kim
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, 34141, Republic of Korea
| | - Ki-Hoan Nam
- Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, 34141, Republic of Korea
| | - Jong Geol Lee
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - In-Jeoung Baek
- Asan Institute for Life Sciences, University of Ulsan College of Medicine, Seoul, Republic of Korea
| | - Beom Jun Lee
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea
| | - Sang-Yoon Nam
- College of Veterinary Medicine, Chungbuk National University, Cheongju 28644, Republic of Korea.
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10
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Han D, Zhang QY, Zhang YL, Han X, Guo SB, Teng F, Yan X, Li HH. Gallic Acid Ameliorates Angiotensin II-Induced Atrial Fibrillation by Inhibiting Immunoproteasome- Mediated PTEN Degradation in Mice. Front Cell Dev Biol 2020; 8:594683. [PMID: 33251220 PMCID: PMC7673442 DOI: 10.3389/fcell.2020.594683] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/13/2020] [Indexed: 11/13/2022] Open
Abstract
Atrial fibrillation (AF) is the most prevalent cardiac arrhythmia and is a major cause of stroke and heart failure. We and others have found that gallic acid (GA) plays a beneficial role in cardiac hypertrophic remodeling and hypertension. However, the effect of GA on angiotensin II (Ang II)-induced AF and atrial remodeling as well as the underlying mechanisms remain unknown. AF was induced in mice by Ang II infusion (2000 ng/kg/min) for 3 weeks. Blood pressure was measured using the tail-cuff method. Atrial volume was evaluated by echocardiography. Atrial remodeling was studied using hematoxylin and eosin, Masson's trichrome, and immunohistochemical staining. Atrial oxidative stress was assessed by dihydroethidium staining. The gene expression of fibrotic and inflammatory markers and protein levels of signaling mediators were measured by quantitative real-time PCR and western blot analysis. In mice, GA administration significantly attenuated Ang II-induced elevation of blood pressure, AF incidence and duration, atrial dilation, fibrosis, inflammation, and oxidative stress compared with the vehicle control. Furthermore, GA downregulated Ang II-induced activity and expression of immunoproteasome subunits (β2i and β5i), which reduced PTEN degradation and led to the inactivation of AKT1 and downstream signaling mediators. Importantly, blocking PTEN activity by VO-Ohpic markedly reversed the GA-mediated protective effects on Ang II-induced AF and atrial remodeling. Therefore, our results provide novel evidence that GA exerts a cardioprotective role by inhibiting immunoproteasome activity, which attenuates PTEN degradation and activation of downstream signaling, and may represent a promising candidate for treating hypertensive AF.
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Affiliation(s)
- Dan Han
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Qi-Yu Zhang
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Yun-Long Zhang
- Emergency Medicine Clinical Research Center, Beijing Chao-Yang Hospital, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Capital Medical University, Beijing, China
| | - Xiao Han
- Emergency Medicine Clinical Research Center, Beijing Chao-Yang Hospital, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Capital Medical University, Beijing, China
| | - Shu-Bin Guo
- Emergency Medicine Clinical Research Center, Beijing Chao-Yang Hospital, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Capital Medical University, Beijing, China
| | - Fei Teng
- Emergency Medicine Clinical Research Center, Beijing Chao-Yang Hospital, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Capital Medical University, Beijing, China
| | - Xiao Yan
- Emergency Medicine Clinical Research Center, Beijing Chao-Yang Hospital, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Capital Medical University, Beijing, China
| | - Hui-Hua Li
- Department of Cardiology, Institute of Cardiovascular Diseases, First Affiliated Hospital of Dalian Medical University, Dalian, China.,Emergency Medicine Clinical Research Center, Beijing Chao-Yang Hospital, Beijing Key Laboratory of Cardiopulmonary Cerebral Resuscitation, Capital Medical University, Beijing, China
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11
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Scalabrin M, Adams V, Labeit S, Bowen TS. Emerging Strategies Targeting Catabolic Muscle Stress Relief. Int J Mol Sci 2020; 21:E4681. [PMID: 32630118 PMCID: PMC7369951 DOI: 10.3390/ijms21134681] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 06/26/2020] [Accepted: 06/29/2020] [Indexed: 12/21/2022] Open
Abstract
Skeletal muscle wasting represents a common trait in many conditions, including aging, cancer, heart failure, immobilization, and critical illness. Loss of muscle mass leads to impaired functional mobility and severely impedes the quality of life. At present, exercise training remains the only proven treatment for muscle atrophy, yet many patients are too ill, frail, bedridden, or neurologically impaired to perform physical exertion. The development of novel therapeutic strategies that can be applied to an in vivo context and attenuate secondary myopathies represents an unmet medical need. This review discusses recent progress in understanding the molecular pathways involved in regulating skeletal muscle wasting with a focus on pro-catabolic factors, in particular, the ubiquitin-proteasome system and its activating muscle-specific E3 ligase RING-finger protein 1 (MuRF1). Mechanistic progress has provided the opportunity to design experimental therapeutic concepts that may affect the ubiquitin-proteasome system and prevent subsequent muscle wasting, with novel advances made in regards to nutritional supplements, nuclear factor kappa-light-chain-enhancer of activated B cells (NFB) inhibitors, myostatin antibodies, β2 adrenergic agonists, and small-molecules interfering with MuRF1, which all emerge as a novel in vivo treatment strategies for muscle wasting.
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Affiliation(s)
- Mattia Scalabrin
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK;
| | - Volker Adams
- Department of Experimental and Molecular Cardiology, TU Dresden, Heart Center Dresden, 01307 Dresden, Germany;
- Dresden Cardiovascular Research Institute and Core Laboratories GmbH, 01067 Dresden, Germany
| | - Siegfried Labeit
- Medical Faculty Mannheim, University of Heidelberg, 68167 Mannheim, Germany;
- Myomedix GmbH, Im Biengarten 36, 69151 Neckargemünd, Germany
| | - T. Scott Bowen
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, UK;
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12
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Caporizzo MA, Chen CY, Prosser BL. Cardiac microtubules in health and heart disease. Exp Biol Med (Maywood) 2019; 244:1255-1272. [PMID: 31398994 DOI: 10.1177/1535370219868960] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes are large (∼40,000 µm3), rod-shaped muscle cells that provide the working force behind each heartbeat. These highly structured cells are packed with dense cytoskeletal networks that can be divided into two groups—the contractile (i.e. sarcomeric) cytoskeleton that consists of filamentous actin-myosin arrays organized into myofibrils, and the non-sarcomeric cytoskeleton, which is composed of β- and γ-actin, microtubules, and intermediate filaments. Together, microtubules and intermediate filaments form a cross-linked scaffold, and these networks are responsible for the delivery of intracellular cargo, the transmission of mechanical signals, the shaping of membrane systems, and the organization of myofibrils and organelles. Microtubules are extensively altered as part of both adaptive and pathological cardiac remodeling, which has diverse ramifications for the structure and function of the cardiomyocyte. In heart failure, the proliferation and post-translational modification of the microtubule network is linked to a number of maladaptive processes, including the mechanical impediment of cardiomyocyte contraction and relaxation. This raises the possibility that reversing microtubule alterations could improve cardiac performance, yet therapeutic efforts will strongly benefit from a deeper understanding of basic microtubule biology in the heart. The aim of this review is to summarize the known physiological roles of the cardiomyocyte microtubule network, the consequences of its pathological remodeling, and to highlight the open and intriguing questions regarding cardiac microtubules. Impact statement Advancements in cell biological and biophysical approaches and super-resolution imaging have greatly broadened our view of tubulin biology over the last decade. In the heart, microtubules and microtubule-based transport help to organize and maintain key structures within the cardiomyocyte, including the sarcomere, intercalated disc, protein clearance machinery and transverse-tubule and sarcoplasmic reticulum membranes. It has become increasingly clear that post translational regulation of microtubules is a key determinant of their sub-cellular functionality. Alterations in microtubule network density, stability, and post-translational modifications are hallmarks of pathological cardiac remodeling, and modified microtubules can directly impede cardiomyocyte contractile function in various forms of heart disease. This review summarizes the functional roles and multi-leveled regulation of the cardiac microtubule cytoskeleton and highlights how refined experimental techniques are shedding mechanistic clarity on the regionally specified roles of microtubules in cardiac physiology and pathophysiology.
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Affiliation(s)
- Matthew A Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Christina Yingxian Chen
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Benjamin L Prosser
- Department of Physiology, Pennsylvania Muscle Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.,Penn Cardiovascular Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
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SPRED2 deficiency elicits cardiac arrhythmias and premature death via impaired autophagy. J Mol Cell Cardiol 2019; 129:13-26. [DOI: 10.1016/j.yjmcc.2019.01.023] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 01/20/2023]
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14
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Ding J, Cong YF, Liu B, Miao J, Wang L. Aberrant Protein Turn-Over Associated With Myofibrillar Disorganization in FHL1 Knockout Mice. Front Genet 2018; 9:273. [PMID: 30083183 PMCID: PMC6065255 DOI: 10.3389/fgene.2018.00273] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 07/04/2018] [Indexed: 12/12/2022] Open
Abstract
Mutations in the FHL1 gene, and FHL1 protein deletion, are associated with rare hereditary myopathies and cardiomyopathies. FHL1-null mice develop age-dependent myopathy and increased autophagic activity. However, the molecular pathway involved in contractile function and increased autophagic activity in the FHL1-null mouse has not yet been fully elucidated. In this study, FHL1 protein was knocked out in mice using Transcription Activator-like Effector Nucleases (TALENs) and the IRS1-FOXO1/mTOR signaling pathway was investigated in skeletal muscles and heart. TALEN constructs caused targeted mutations in 30% of newborn mice; these mutations caused a deletion of 1–13 base pairs which blocked synthesis of the full-length FHL1 protein. Furthermore, 2.5-month old FHL1-null male mice were not prone to global muscular fatigue when compared with WT littermates, but histological analysis and ultrastructural analysis by transmission electron microscopy confirmed the presence of myofibrillar disorganization and the accumulation of autophagosome or autolysosome-like structures in FHL1-null mice. Moreover, autophagy and mitophagy were both activated in FHL1 KO mice and the degradation of autophagic lysosomes was impeded. Enhanced autophagic activity in FHL1 KO mice was induced by FOXO1 up-regulation and protein synthesis was increased via mTOR. The cytoskeletal proteins, MYBPC2 and LDB3, were involved in the formation of pathological changes in FHL1 KO mice. Markers of early differentiation (MEF2C and MYOD1) and terminal differentiation (total MYH) were both up-regulated in tibialis anterior (TA) muscles in FHL1 KO mice. The number of type I and type II fibers increased in FHL1-null TA muscles, but the number of type| | b, and type | | d fibers were both reduced in FHL1-null TA muscles. The results obtained from the heart were consistent with those from the skeletal muscle and indicated autophagic activation by FOXO1 and an increase in protein synthesis via mTOR also occurred in the heart tissue of FHL1 knockout mice. In conclusion, aberrant protein turn-over associated with myofibrillar disorganization in FHL1 knockout mice. the up-regulation of FOXO1 was associated with enhanced autophagic activity and pathological changes in the muscle fibers of FHL1 KO mice. These results indicated that autophagy activated by FOXO1 is a promising therapeutic target for hereditary myopathies and cardiomyopathies induced by FHL1.
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Affiliation(s)
- Jingjing Ding
- Medical Research Center of Shengjing Hospital, China Medical University, Shenyang, China
| | - Yan Fei Cong
- Medical Research Center of Shengjing Hospital, China Medical University, Shenyang, China
| | - Bo Liu
- Medical Research Center of Shengjing Hospital, China Medical University, Shenyang, China
| | - Jianing Miao
- Medical Research Center of Shengjing Hospital, China Medical University, Shenyang, China
| | - Lili Wang
- Medical Research Center of Shengjing Hospital, China Medical University, Shenyang, China
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15
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Della Guardia L, Thomas MA, Cena H. Insulin Sensitivity and Glucose Homeostasis Can Be Influenced by Metabolic Acid Load. Nutrients 2018; 10:E618. [PMID: 29762478 PMCID: PMC5986498 DOI: 10.3390/nu10050618] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 05/08/2018] [Accepted: 05/10/2018] [Indexed: 01/04/2023] Open
Abstract
Recent epidemiological findings suggest that high levels of dietary acid load can affect insulin sensitivity and glucose metabolism. Consumption of high protein diets results in the over-production of metabolic acids which has been associated with the development of chronic metabolic disturbances. Mild metabolic acidosis has been shown to impair peripheral insulin action and several epidemiological findings suggest that metabolic acid load markers are associated with insulin resistance and impaired glycemic control through an interference intracellular insulin signaling pathways and translocation. In addition, higher incidence of diabetes, insulin resistance, or impaired glucose control have been found in subjects with elevated metabolic acid load markers. Hence, lowering dietary acid load may be relevant for improving glucose homeostasis and prevention of type 2 diabetes development on a long-term basis. However, limitations related to patient acid load estimation, nutritional determinants, and metabolic status considerably flaws available findings, and the lack of solid data on the background physiopathology contributes to the questionability of results. Furthermore, evidence from interventional studies is very limited and the trials carried out report no beneficial results following alkali supplementation. Available literature suggests that poor acid load control may contribute to impaired insulin sensitivity and glucose homeostasis, but it is not sufficiently supportive to fully elucidate the issue and additional well-designed studies are clearly needed.
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Affiliation(s)
- Lucio Della Guardia
- Laboratory of Dietetics and Clinical Nutrition Department of Public Health, Experimental and Forensic Medicine, University of Pavia, 27100 Pavia, Italy.
| | - Michael Alex Thomas
- Department of Biology, Center for Obesity Reversal, Georgia State University, Atlanta, GA 30302, USA.
| | - Hellas Cena
- Laboratory of Dietetics and Clinical Nutrition Department of Public Health, Experimental and Forensic Medicine, University of Pavia, 27100 Pavia, Italy.
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16
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Wang L, Geist J, Grogan A, Hu LYR, Kontrogianni-Konstantopoulos A. Thick Filament Protein Network, Functions, and Disease Association. Compr Physiol 2018; 8:631-709. [PMID: 29687901 PMCID: PMC6404781 DOI: 10.1002/cphy.c170023] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sarcomeres consist of highly ordered arrays of thick myosin and thin actin filaments along with accessory proteins. Thick filaments occupy the center of sarcomeres where they partially overlap with thin filaments. The sliding of thick filaments past thin filaments is a highly regulated process that occurs in an ATP-dependent manner driving muscle contraction. In addition to myosin that makes up the backbone of the thick filament, four other proteins which are intimately bound to the thick filament, myosin binding protein-C, titin, myomesin, and obscurin play important structural and regulatory roles. Consistent with this, mutations in the respective genes have been associated with idiopathic and congenital forms of skeletal and cardiac myopathies. In this review, we aim to summarize our current knowledge on the molecular structure, subcellular localization, interacting partners, function, modulation via posttranslational modifications, and disease involvement of these five major proteins that comprise the thick filament of striated muscle cells. © 2018 American Physiological Society. Compr Physiol 8:631-709, 2018.
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Affiliation(s)
- Li Wang
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Janelle Geist
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Li-Yen R. Hu
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
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17
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Métais A, Lamsoul I, Melet A, Uttenweiler-Joseph S, Poincloux R, Stefanovic S, Valière A, Gonzalez de Peredo A, Stella A, Burlet-Schiltz O, Zaffran S, Lutz PG, Moog-Lutz C. Asb2α-Filamin A Axis Is Essential for Actin Cytoskeleton Remodeling During Heart Development. Circ Res 2018; 122:e34-e48. [PMID: 29374072 DOI: 10.1161/circresaha.117.312015] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Revised: 01/18/2018] [Accepted: 01/24/2018] [Indexed: 11/16/2022]
Abstract
RATIONALE Heart development involves differentiation of cardiac progenitors and assembly of the contractile sarcomere apparatus of cardiomyocytes. However, little is known about the mechanisms that regulate actin cytoskeleton remodeling during cardiac cell differentiation. OBJECTIVE The Asb2α (Ankyrin repeat-containing protein with a suppressor of cytokine signaling box 2) CRL5 (cullin 5 RING E3 ubiquitin ligase) triggers polyubiquitylation and subsequent degradation by the proteasome of FLNs (filamins). Here, we investigate the role of Asb2α in heart development and its mechanisms of action. METHODS AND RESULTS Using Asb2 knockout embryos, we show that Asb2 is an essential gene, critical to heart morphogenesis and function, although its loss does not interfere with the overall patterning of the embryonic heart tube. We show that the Asb2α E3 ubiquitin ligase controls Flna stability in immature cardiomyocytes. Importantly, Asb2α-mediated degradation of the actin-binding protein Flna marks a previously unrecognized intermediate step in cardiac cell differentiation characterized by cell shape changes and actin cytoskeleton remodeling. We further establish that in the absence of Asb2α, myofibrils are disorganized and that heartbeats are inefficient, leading to embryonic lethality in mice. CONCLUSIONS These findings identify Asb2α as an unsuspected key regulator of cardiac cell differentiation and shed light on the molecular and cellular mechanisms determining the onset of myocardial cell architecture and its link with early cardiac function. Although Flna is known to play roles in cytoskeleton organization and to be required for heart function, this study now reveals that its degradation mediated by Asb2α ensures essential functions in differentiating cardiac progenitors.
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Affiliation(s)
- Arnaud Métais
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Isabelle Lamsoul
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Armelle Melet
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Sandrine Uttenweiler-Joseph
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Renaud Poincloux
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Sonia Stefanovic
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Amélie Valière
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Anne Gonzalez de Peredo
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Alexandre Stella
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Odile Burlet-Schiltz
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Stéphane Zaffran
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.)
| | - Pierre G Lutz
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.).
| | - Christel Moog-Lutz
- From the Institut de Pharmacologie et de Biologie Structurale, IPBS, Université de Toulouse, CNRS, UPS, France (A. Métais, I.L., A. Melet, S.U.-J., R.P., A.V., A.G.d.P., A.S., O.B.-S., P.G.L., C.M.-L.); CNRS UMR8601, Université Paris Descartes, France (A. Melet); and Aix Marseille Univ, INSERM, MMG, France (S.S., S.Z.).
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The down-regulation of cardiac contractile proteins underlies myocardial depression during sepsis and is mitigated by carbon monoxide. Biochem Biophys Res Commun 2018; 495:1668-1674. [DOI: 10.1016/j.bbrc.2017.12.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 12/04/2017] [Indexed: 01/18/2023]
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19
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Shimizu H, Langenbacher AD, Huang J, Wang K, Otto G, Geisler R, Wang Y, Chen JN. The Calcineurin-FoxO-MuRF1 signaling pathway regulates myofibril integrity in cardiomyocytes. eLife 2017; 6:27955. [PMID: 28826496 PMCID: PMC5576919 DOI: 10.7554/elife.27955] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 08/18/2017] [Indexed: 12/21/2022] Open
Abstract
Altered Ca2+ handling is often present in diseased hearts undergoing structural remodeling and functional deterioration. However, whether Ca2+ directly regulates sarcomere structure has remained elusive. Using a zebrafish ncx1 mutant, we explored the impacts of impaired Ca2+ homeostasis on myofibril integrity. We found that the E3 ubiquitin ligase murf1 is upregulated in ncx1-deficient hearts. Intriguingly, knocking down murf1 activity or inhibiting proteasome activity preserved myofibril integrity, revealing a MuRF1-mediated proteasome degradation mechanism that is activated in response to abnormal Ca2+ homeostasis. Furthermore, we detected an accumulation of the murf1 regulator FoxO in the nuclei of ncx1-deficient cardiomyocytes. Overexpression of FoxO in wild type cardiomyocytes induced murf1 expression and caused myofibril disarray, whereas inhibiting Calcineurin activity attenuated FoxO-mediated murf1 expression and protected sarcomeres from degradation in ncx1-deficient hearts. Together, our findings reveal a novel mechanism by which Ca2+ overload disrupts myofibril integrity by activating a Calcineurin-FoxO-MuRF1-proteosome signaling pathway.
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Affiliation(s)
- Hirohito Shimizu
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Adam D Langenbacher
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Jie Huang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Kevin Wang
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
| | - Georg Otto
- Genetics and Genomic Medicine, UCL Institute of Child Health, London, United Kingdom
| | - Robert Geisler
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Karlsruhe, Germany
| | - Yibin Wang
- Department of Anesthesiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States.,Department of Medicine and Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, United States
| | - Jau-Nian Chen
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, Los Angeles, United States
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Thokala S, Inapurapu S, Bodiga VL, Vemuri PK, Bodiga S. Loss of ErbB2-PI3K/Akt signaling prevents zinc pyrithione-induced cardioprotection during ischemia/reperfusion. Biomed Pharmacother 2017; 88:309-324. [PMID: 28119233 DOI: 10.1016/j.biopha.2017.01.065] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/10/2017] [Accepted: 01/10/2017] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES The purpose of this study was to determine if zinc homeostasis is affected during ischemia/reperfusion, if so, whether zinc pyrithione limits myocardial cell death and improves hemodynamics when administered as an adjunct to reperfusion and if ErbB receptor tyrosine kinases that are important for the long-term structural integrity of the heart are indispensable for reperfusion salvage. METHODS Isolated perfused rat hearts were subjected to 35min of global ischemia and reperfused for 120min to determine the relative intracellular zinc levels by TSQ staining. The hearts were reperfused in the presence of incremental concentrations of zinc pyrithione for the first 10min during reperfusion. Silencing or blockade of ErbB2 using a monoclonal antibody, ErbB2 kinase inhibition and PI3kinase inhibition was used to study their critical role in zinc pyrithione-induced cardioprotection. RESULTS We found that there was a profound decrease in intracellular zinc after ischemia/reperfusion resulting in increased apoptosis, caspase-3 activation, and infarct size. A dose-dependent reduction of infarct size with zinc pyrithione in the range of 5-20μmol/l (optimal protection was seen at 10μmol/l with infarct size of 16±2% vs. I/R vehicle, 33±2%, p<0.01). Increased TUNEL staining and caspase-3 activity observed after ischemia/reperfusion were attenuated by zinc pyrithione administration during the reperfusion. Moreover, this protection was sensitive to silencing and blockade of ErbB2, inhibition of ErbB2 kinase activity or PI3-kinase activity. Western blot analysis revealed that zinc pyrithione resulted in decreased caspase-3 activation, rapid stabilization of ErbB2/ErbB1 heterodimers, and increased activation of PI3K/Akt signaling cascade. CONCLUSIONS Zinc pyrithione attenuates lethal perfusion-induced injury in a manner that is reliant on ErbB2/PI3K/Akt activity.
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Affiliation(s)
- Sandhya Thokala
- Department of Biochemistry, Kakatiya University, Vidyaranyapuri, Warangal, Telangana, India
| | - Santhipriya Inapurapu
- Institute of Genetics & Hospital for Genetic Diseases, Begumpet, Osmania University, Hyderabad, Telangana, India
| | - Vijaya Lakshmi Bodiga
- Institute of Genetics & Hospital for Genetic Diseases, Begumpet, Osmania University, Hyderabad, Telangana, India
| | - Praveen Kumar Vemuri
- Department of Biotechnology, KL University, Vaddeswaram, Guntur, Andhra Pradesh, India
| | - Sreedhar Bodiga
- Department of Biochemistry, Kakatiya University, Vidyaranyapuri, Warangal, Telangana, India.
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Parry TL, Willis MS. Cardiac ubiquitin ligases: Their role in cardiac metabolism, autophagy, cardioprotection and therapeutic potential. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1862:2259-2269. [PMID: 27421947 PMCID: PMC5159290 DOI: 10.1016/j.bbadis.2016.07.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Revised: 07/05/2016] [Accepted: 07/11/2016] [Indexed: 12/19/2022]
Abstract
Both the ubiquitin-proteasome system (UPS) and the lysosomal autophagy system have emerged as complementary key players responsible for the turnover of cellular proteins. The regulation of protein turnover is critical to cardiomyocytes as post-mitotic cells with very limited regenerative capacity. In this focused review, we describe the emerging interface between the UPS and autophagy, with E3's regulating autophagy at two critical points through multiple mechanisms. Moreover, we discuss recent insights in how both the UPS and autophagy can alter metabolism at various levels, to present new ways to think about therapeutically regulating autophagy in a focused manner to optimize disease-specific cardioprotection, without harming the overall homeostasis of protein quality control. This article is part of a Special Issue entitled: The role of post-translational protein modifications on heart and vascular metabolism edited by Jason R.B. Dyck & Jan F.C. Glatz.
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Affiliation(s)
- Traci L Parry
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA; Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC, USA
| | - Monte S Willis
- McAllister Heart Institute, University of North Carolina, Chapel Hill, NC, USA; Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC, USA; Department of Pharmacology, University of North Carolina, Chapel Hill, NC, USA.
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Cho HC. Modeling and Genome-Editing Brugada Syndrome in a Dish ∗. J Am Coll Cardiol 2016; 68:2097-2098. [DOI: 10.1016/j.jacc.2016.09.911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 11/16/2022]
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Mezzano V, Liang Y, Wright AT, Lyon RC, Pfeiffer E, Song MY, Gu Y, Dalton ND, Scheinman M, Peterson KL, Evans SM, Fowler S, Cerrone M, McCulloch AD, Sheikh F. Desmosomal junctions are necessary for adult sinus node function. Cardiovasc Res 2016; 111:274-86. [PMID: 27097650 DOI: 10.1093/cvr/cvw083] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 04/08/2016] [Indexed: 12/20/2022] Open
Abstract
AIMS Current mechanisms driving cardiac pacemaker function have focused on ion channel and gap junction channel function, which are essential for action potential generation and propagation between pacemaker cells. However, pacemaker cells also harbour desmosomes that structurally anchor pacemaker cells to each other in tissue, but their role in pacemaker function remains unknown. METHODS AND RESULTS To determine the role of desmosomes in pacemaker function, we generated a novel mouse model harbouring cardiac conduction-specific ablation (csKO) of the central desmosomal protein, desmoplakin (DSP) using the Hcn4-Cre-ERT2 mouse line. Hcn4-Cre targets cells of the adult mouse sinoatrial node (SAN) and can ablate DSP expression in the adult DSP csKO SAN resulting in specific loss of desmosomal proteins and structures. Dysregulation of DSP via loss-of-function (adult DSP csKO mice) and mutation (clinical case of a patient harbouring a pathogenic DSP variant) in mice and man, respectively, revealed that desmosomal dysregulation is associated with a primary phenotype of increased sinus pauses/dysfunction in the absence of cardiomyopathy. Underlying defects in beat-to-beat regulation were also observed in DSP csKO mice in vivo and intact atria ex vivo. DSP csKO SAN exhibited migrating lead pacemaker sites associated with connexin 45 loss. In vitro studies exploiting ventricular cardiomyocytes that harbour DSP loss and concurrent early connexin loss phenocopied the loss of beat-to-beat regulation observed in DSP csKO mice and atria, extending the importance of DSP-associated mechanisms in driving beat-to-beat regulation of working cardiomyocytes. CONCLUSION We provide evidence of a mechanism that implicates an essential role for desmosomes in cardiac pacemaker function, which has broad implications in better understanding mechanisms underlying beat-to-beat regulation as well as sinus node disease and dysfunction.
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Affiliation(s)
- Valeria Mezzano
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Yan Liang
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Adam T Wright
- Department of Bioengineering, University of California-San Diego, La Jolla, CA 92093, USA
| | - Robert C Lyon
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Emily Pfeiffer
- Department of Bioengineering, University of California-San Diego, La Jolla, CA 92093, USA
| | - Michael Y Song
- Scripps Translational Science Institute, Department of Medicine, Scripps Green Hospital, La Jolla, CA 92037, USA
| | - Yusu Gu
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Nancy D Dalton
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Melvin Scheinman
- Department of Cardiac Electrophysiology, University of California-San Francisco, San Francisco, CA 94143, USA
| | - Kirk L Peterson
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
| | - Sylvia M Evans
- Skaggs School of Pharmacy, University of California-San Diego, La Jolla, CA 92093, USA
| | - Steven Fowler
- Cardiovascular Genetics Program, New York University School of Medicine, New York, NY 10016, USA
| | - Marina Cerrone
- Cardiovascular Genetics Program, New York University School of Medicine, New York, NY 10016, USA
| | - Andrew D McCulloch
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA Department of Bioengineering, University of California-San Diego, La Jolla, CA 92093, USA
| | - Farah Sheikh
- Department of Medicine, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0613C, USA
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Abstract
The main function of the heart is to pump blood to the different parts of the organism, a task that is efficiently accomplished through proper electric and metabolic coupling between cardiac cells, ensured by gap junctions (GJ). Cardiomyocytes are the major cell population in the heart, and as cells with low mitotic activity, are highly dependent upon mechanisms of protein degradation. In the heart, both the ubiquitin-proteasome system (UPS) and autophagy participate in the fine-tune regulation of cardiac remodelling and function, either in physiological or pathological conditions. Indeed, besides controlling cardiac signalling pathways, UPS and autophagy have been implicated in the turnover of several myocardial proteins. Degradation of Cx43, the major ventricular GJ protein, has been associated to up-regulation of autophagy at the onset of heart ischemia and ischemia/reperfusion (I/R), which can have profound implications upon cardiac function. In this review, we present recent studies devoted to the involvement of autophagy and UPS in heart homoeostasis, with a particular focus on GJ.
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Lyon RC, Zanella F, Omens JH, Sheikh F. Mechanotransduction in cardiac hypertrophy and failure. Circ Res 2015; 116:1462-1476. [PMID: 25858069 PMCID: PMC4394185 DOI: 10.1161/circresaha.116.304937] [Citation(s) in RCA: 218] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 03/13/2015] [Indexed: 01/10/2023]
Abstract
Cardiac muscle cells have an intrinsic ability to sense and respond to mechanical load through a process known as mechanotransduction. In the heart, this process involves the conversion of mechanical stimuli into biochemical events that induce changes in myocardial structure and function. Mechanotransduction and its downstream effects function initially as adaptive responses that serve as compensatory mechanisms during adaptation to the initial load. However, under prolonged and abnormal loading conditions, the remodeling processes can become maladaptive, leading to altered physiological function and the development of pathological cardiac hypertrophy and heart failure. Although the mechanisms underlying mechanotransduction are far from being fully elucidated, human and mouse genetic studies have highlighted various cytoskeletal and sarcolemmal structures in cardiac myocytes as the likely candidates for load transducers, based on their link to signaling molecules and architectural components important in disease pathogenesis. In this review, we summarize recent developments that have uncovered specific protein complexes linked to mechanotransduction and mechanotransmission within the sarcomere, the intercalated disc, and at the sarcolemma. The protein structures acting as mechanotransducers are the first step in the process that drives physiological and pathological cardiac hypertrophy and remodeling, as well as the transition to heart failure, and may provide better insights into mechanisms driving mechanotransduction-based diseases.
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Affiliation(s)
- Robert C. Lyon
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Fabian Zanella
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Jeffrey H. Omens
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
- Department of Bioengineering, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Farah Sheikh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
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Martins-Marques T, Ribeiro-Rodrigues T, Pereira P, Codogno P, Girao H. Autophagy and ubiquitination in cardiovascular diseases. DNA Cell Biol 2015; 34:243-51. [PMID: 25602806 DOI: 10.1089/dna.2014.2765] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
A main function of the heart is to pump blood to the tissues and organs of the body. Although formed by different types of cells, the cardiomyocytes are the ones responsible for the coordinated and synchronized heart contraction. Given their low mitotic activity, cardiomyocytes largely depend on protein degradation mechanisms to maintain proteostasis and energetic balance. Autophagy, one of the main pathways whereby cells eliminate damaged, nonfunctional, or obsolete proteins, and organelles, is vital to ensure cell function, including in cardiomyocytes, both in rest and stress conditions. However, the impact of autophagy activation in the heart, being either protective or harmful, is not consensual and likely depends upon the severity of the stimuli and consequently the autophagy players involved. One of the signals that direct proteins for autophagy degradation, namely in the context of heart disorders, is ubiquitin. Indeed, the attachment of ubiquitin moieties to a target substrate and further recognition by autophagy adaptors constitute a main regulatory pathway that directs proteins to the lysosome. Therefore, a better understanding of the mechanisms and signals that regulate the autophagy process in the heart, including substrates targeting, is of utmost importance to design new approaches directed to this degradation pathway. We have previously shown that ubiquitination of the gap junction (GJ) protein Connexin43 (Cx43) triggers its degradation by autophagy through a process that requires the ubiquitin adaptors epidermal growth factor receptor substrate 15 (Eps15) and p62. This is particularly relevant in the heart because GJs, that form intercellular channels, are responsible for the rapid and efficient anisotropic propagation of the electrical impulse through the cardiomyocytes, essential for synchronized contraction of the cardiac muscle. In this review, we present recent studies devoted to the involvement of autophagy in heart homeostasis, with a particular focus on ubiquitin and GJs.
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Affiliation(s)
- Tania Martins-Marques
- 1 Centre of Ophthalmology and Vision Sciences, Institute of Biomedical Imaging and Life Sciences (IBILI), Faculty of Medicine, University of Coimbra , Coimbra, Portugal
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Degradation of M(r) 25,000 protein by cathepsin L-like protease in Xenopus laevis oocytes. Protein J 2014; 33:150-6. [PMID: 24510540 DOI: 10.1007/s10930-014-9542-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A phosphorylated protein with a molecular mass of 25,000 (pp25) is involved in Xenopus laevis vitellogenin B1 and partially overlaps with phosvitin and lipovitellin 2. The protease responsible for pp25 degradation was studied in vitro since this occurs during embryogenesis. Initially, a protease thought to be a contaminant of the purified pp25 preparation was analyzed and an antipain-sensitive protease presumed to be involved. When commercially available proteases were examined, pp25 was not degraded by calpain I or 20S proteasome, but it was degraded by cathepsin L in vitro. A survey of the protease responsible for pp25 degradation in the cytoplasm of Xenopus oocytes found partially purified pp25 was degraded in partly antipain-sensitive manner. These results suggest that an antipain-sensitive protease or cathepsin L (or a related protease) is a candidate for pp25 degradation.
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