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Maroli G, Schänzer A, Günther S, Garcia-Gonzalez C, Rupp S, Schlierbach H, Chen Y, Graumann J, Wietelmann A, Kim J, Braun T. Inhibition of autophagy prevents cardiac dysfunction at early stages of cardiomyopathy in Bag3-deficient hearts. J Mol Cell Cardiol 2024; 193:53-66. [PMID: 38838815 DOI: 10.1016/j.yjmcc.2024.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 05/31/2024] [Accepted: 06/02/2024] [Indexed: 06/07/2024]
Abstract
The HSP70 co-chaperone BAG3 targets unfolded proteins to degradation via chaperone assisted selective autophagy (CASA), thereby playing pivotal roles in the proteostasis of adult cardiomyocytes (CMs). However, the complex functions of BAG3 for regulating autophagy in cardiac disease are not completely understood. Here, we demonstrate that conditional inactivation of Bag3 in murine CMs leads to age-dependent dysregulation of autophagy, associated with progressive cardiomyopathy. Surprisingly, Bag3-deficient CMs show increased canonical and non-canonical autophagic flux in the juvenile period when first signs of cardiac dysfunction appear, but reduced autophagy during later stages of the disease. Juvenile Bag3-deficient CMs are characterized by decreased levels of soluble proteins involved in synchronous contraction of the heart, including the gap junction protein Connexin 43 (CX43). Reiterative administration of chloroquine (CQ), an inhibitor of canonical and non-canonical autophagy, but not inactivation of Atg5, restores normal concentrations of soluble cardiac proteins in juvenile Bag3-deficient CMs without an increase of detergent-insoluble proteins, leading to complete recovery of early-stage cardiac dysfunction in Bag3-deficient mice. We conclude that loss of Bag3 in CMs leads to age-dependent differences in autophagy and cardiac dysfunction. Increased non-canonical autophagic flux in the juvenile period removes soluble proteins involved in cardiac contraction, leading to early-stage cardiomyopathy, which is prevented by reiterative CQ treatment.
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Affiliation(s)
- Giovanni Maroli
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.; Department of Lung Development and Remodeling, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany..
| | - Anne Schänzer
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Stefan Günther
- Max Planck Institute for Heart and Lung Research, Bioinformatics and deep sequencing platform, Ludwigstr. 43., 61231 Bad Nauheim, Germany
| | - Claudia Garcia-Gonzalez
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.; Department of Morphology and Cell Biology, University of Oviedo, 33006 Oviedo, Spain
| | - Stefan Rupp
- Department of Pediatric Cardiology and Congenital Heart Disease, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Hannah Schlierbach
- Institute of Neuropathology, Justus Liebig University Giessen, 35392 Giessen, Germany
| | - Yanpu Chen
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Johannes Graumann
- Biomolecular Mass Spectrometry, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.; The German Center for Cardiovascular Research (DZHK), Partner Site Rhine-Main
| | - Astrid Wietelmann
- Magnetic Resonance Imaging Group, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Johnny Kim
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, 61231 Bad Nauheim, Germany.; The German Center for Cardiovascular Research (DZHK), Partner Site Rhine-Main..
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2
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Wang J, Tomar D, Martin TG, Dubey S, Dubey PK, Song J, Landesberg G, McCormick MG, Myers VD, Merali S, Merali C, Lemster B, McTiernan CF, Khalili K, Madesh M, Cheung JY, Kirk JA, Feldman AM. Bag3 Regulates Mitochondrial Function and the Inflammasome Through Canonical and Noncanonical Pathways in the Heart. JACC Basic Transl Sci 2023; 8:820-839. [PMID: 37547075 PMCID: PMC10401293 DOI: 10.1016/j.jacbts.2022.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 12/14/2022] [Accepted: 12/29/2022] [Indexed: 08/08/2023]
Abstract
B-cell lymphoma 2-associated athanogene-3 (Bag3) is expressed in all animal species, with Bag3 levels being most prominent in the heart, the skeletal muscle, the central nervous system, and in many cancers. Preclinical studies of Bag3 biology have focused on animals that have developed compromised cardiac function; however, the present studies were performed to identify the pathways perturbed in the heart even before the occurrence of clinical signs of dilatation and failure of the heart. These studies show that hearts carrying variants that knockout one allele of BAG3 have significant alterations in multiple cellular pathways including apoptosis, autophagy, mitochondrial homeostasis, and the inflammasome.
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Affiliation(s)
- JuFang Wang
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Dhadendra Tomar
- Department of Internal Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina, USA
| | - Thomas G. Martin
- Department of Cell and Molecular Physiology, Loyola University Strich School of Medicine, Maywood, Illinois, USA
| | - Shubham Dubey
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Praveen K. Dubey
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Jianliang Song
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Gavin Landesberg
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Michael G. McCormick
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | | | - Salim Merali
- Temple University School of Pharmacy, Philadelphia, Pennsylvania, USA
| | - Carmen Merali
- Temple University School of Pharmacy, Philadelphia, Pennsylvania, USA
| | - Bonnie Lemster
- Department of Medicine, Division of Cardiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Charles F. McTiernan
- Department of Medicine, Division of Cardiology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Kamel Khalili
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Muniswamy Madesh
- Department of Medicine, Center for Precision Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
| | - Joseph Y. Cheung
- Division of Renal Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Jonathan A. Kirk
- Department of Cell and Molecular Physiology, Loyola University Strich School of Medicine, Maywood, Illinois, USA
| | - Arthur M. Feldman
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
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3
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Koslow M, Mondaca-Ruff D, Xu X. Transcriptome studies of inherited dilated cardiomyopathies. Mamm Genome 2023; 34:312-322. [PMID: 36749382 PMCID: PMC10426000 DOI: 10.1007/s00335-023-09978-z] [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: 07/25/2022] [Accepted: 01/16/2023] [Indexed: 02/08/2023]
Abstract
Dilated cardiomyopathy (DCM) is a group of heart muscle diseases that often lead to heart failure, with more than 50 causative genes have being linked to DCM. The heterogenous nature of the inherited DCMs suggest the need of precision medicine. Consistent with this emerging concept, transcriptome studies in human patients with DCM indicated distinct molecular signature for DCMs of different genetic etiology. To facilitate this line of research, we reviewed the status of transcriptome studies of inherited DCMs by focusing on three predominant DCM causative genes, TTN, LMNA, and BAG3. Besides studies in human patients, we summarized transcriptomic analysis of these inherited DCMs in a variety of model systems ranging from iPSCs to rodents and zebrafish. We concluded that the RNA-seq technology is a powerful genomic tool that has already led to the discovery of new modifying genes, signaling pathways, and related therapeutic avenues. We also pointed out that both temporal (different pathological stages) and spatial (different cell types) information need to be considered for future transcriptome studies. While an important bottle neck is the low throughput in experimentally testing differentially expressed genes, new technologies in efficient animal models such as zebrafish starts to be developed. It is anticipated that the RNA-seq technology will continue to uncover both unique and common pathological events, aiding the development of precision medicine for inherited DCMs.
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Affiliation(s)
- Matthew Koslow
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - David Mondaca-Ruff
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA.
- Department of Cardiovascular Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
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4
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Yerabandi N, Kouznetsova VL, Kesari S, Tsigelny IF. The role of BAG3 in dilated cardiomyopathy and its association with Charcot-Marie-Tooth disease type 2. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 2022; 41:59-75. [PMID: 35832504 PMCID: PMC9237749 DOI: 10.36185/2532-1900-071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/13/2022] [Indexed: 11/03/2022]
Abstract
Bcl2-associated athanogene 3 (BAG3) is a multifunctional cochaperone responsible for protein quality control within cells. BAG3 interacts with chaperones HSPB8 and Hsp70 to transport misfolded proteins to the Microtubule Organizing Center (MTOC) and degrade them in autophagosomes in a process known as Chaperone Assisted Selective Autophagy (CASA). Mutations in the second conserved IPV motif of BAG3 are known to cause Dilated Cardiomyopathy (DCM) by inhibiting adequate removal of non-native proteins. The proline 209 to leucine (P209L) BAG3 mutant in particular causes the aggregation of BAG3 and misfolded proteins as well as the sequestration of essential chaperones. The exact mechanisms of protein aggregation in DCM are unknown. However, the similar presence of insoluble protein aggregates in Charcot-Marie-Tooth disease type 2 (CMT2) induced by the proline 182 to leucine (P182L) HSPB1 mutant points to a possible avenue for future research: IPV motif. In this review, we summarize the molecular mechanisms of CASA and the currently known pathological effects of mutated BAG3 in DCM. Additionally, we will provide insight on the importance of the IPV motif in protein aggregation by analyzing a potential association between DCM and CMT2.
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Affiliation(s)
- Nitya Yerabandi
- REHS program, San Diego Supercomputer Center, University of California, San Diego, CA, USA
| | - Valentina L. Kouznetsova
- San Diego Supercomputer Center, University of California, San Diego, CA, USA,Biana, La Jolla, CA, USA
| | | | - Igor F. Tsigelny
- Correspondence Igor F. Tsigelny Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0505, USA. E-mail:
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5
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Genetic Insights into Primary Restrictive Cardiomyopathy. J Clin Med 2022; 11:jcm11082094. [PMID: 35456187 PMCID: PMC9027761 DOI: 10.3390/jcm11082094] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/05/2022] [Accepted: 04/06/2022] [Indexed: 12/04/2022] Open
Abstract
Restrictive cardiomyopathy is a rare cardiac disease causing severe diastolic dysfunction, ventricular stiffness and dilated atria. In consequence, it induces heart failure often with preserved ejection fraction and is associated with a high mortality. Since it is a poor clinical prognosis, patients with restrictive cardiomyopathy frequently require heart transplantation. Genetic as well as non-genetic factors contribute to restrictive cardiomyopathy and a significant portion of cases are of unknown etiology. However, the genetic forms of restrictive cardiomyopathy and the involved molecular pathomechanisms are only partially understood. In this review, we summarize the current knowledge about primary genetic restrictive cardiomyopathy and describe its genetic landscape, which might be of interest for geneticists as well as for cardiologists.
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6
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Bang ML, Bogomolovas J, Chen J. Understanding the molecular basis of cardiomyopathy. Am J Physiol Heart Circ Physiol 2022; 322:H181-H233. [PMID: 34797172 PMCID: PMC8759964 DOI: 10.1152/ajpheart.00562.2021] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/16/2021] [Accepted: 11/16/2021] [Indexed: 02/03/2023]
Abstract
Inherited cardiomyopathies are a major cause of mortality and morbidity worldwide and can be caused by mutations in a wide range of proteins located in different cellular compartments. The present review is based on Dr. Ju Chen's 2021 Robert M. Berne Distinguished Lectureship of the American Physiological Society Cardiovascular Section, in which he provided an overview of the current knowledge on the cardiomyopathy-associated proteins that have been studied in his laboratory. The review provides a general summary of the proteins in different compartments of cardiomyocytes associated with cardiomyopathies, with specific focus on the proteins that have been studied in Dr. Chen's laboratory.
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Affiliation(s)
- Marie-Louise Bang
- Institute of Genetic and Biomedical Research (IRGB), National Research Council (CNR), Milan Unit, Milan, Italy
- IRCCS Humanitas Research Hospital, Rozzano (Milan), Italy
| | - Julius Bogomolovas
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Division of Cardiovascular Medicine, Department of Medicine Cardiology, University of California, San Diego, La Jolla, California
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7
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With or without You: Co-Chaperones Mediate Health and Disease by Modifying Chaperone Function and Protein Triage. Cells 2021; 10:cells10113121. [PMID: 34831344 PMCID: PMC8619055 DOI: 10.3390/cells10113121] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 11/05/2021] [Accepted: 11/09/2021] [Indexed: 01/18/2023] Open
Abstract
Heat shock proteins (HSPs) are a family of molecular chaperones that regulate essential protein refolding and triage decisions to maintain protein homeostasis. Numerous co-chaperone proteins directly interact and modify the function of HSPs, and these interactions impact the outcome of protein triage, impacting everything from structural proteins to cell signaling mediators. The chaperone/co-chaperone machinery protects against various stressors to ensure cellular function in the face of stress. However, coding mutations, expression changes, and post-translational modifications of the chaperone/co-chaperone machinery can alter the cellular stress response. Importantly, these dysfunctions appear to contribute to numerous human diseases. Therapeutic targeting of chaperones is an attractive but challenging approach due to the vast functions of HSPs, likely contributing to the off-target effects of these therapies. Current efforts focus on targeting co-chaperones to develop precise treatments for numerous diseases caused by defects in protein quality control. This review focuses on the recent developments regarding selected HSP70/HSP90 co-chaperones, with a concentration on cardioprotection, neuroprotection, cancer, and autoimmune diseases. We also discuss therapeutic approaches that highlight both the utility and challenges of targeting co-chaperones.
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8
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Kirk JA, Cheung JY, Feldman AM. Therapeutic targeting of BAG3: considering its complexity in cancer and heart disease. J Clin Invest 2021; 131:e149415. [PMID: 34396980 DOI: 10.1172/jci149415] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Bcl2-associated athanogene-3 (BAG3) is expressed ubiquitously in humans, but its levels are highest in the heart, the skeletal muscle, and the central nervous system; it is also elevated in many cancers. BAG3's diverse functions are supported by its multiple protein-protein binding domains, which couple with small and large heat shock proteins, members of the Bcl2 family, other antiapoptotic proteins, and various sarcomere proteins. In the heart, BAG3 inhibits apoptosis, promotes autophagy, couples the β-adrenergic receptor with the L-type Ca2+ channel, and maintains the structure of the sarcomere. In cancer cells, BAG3 binds to and supports an identical array of prosurvival proteins, and it may represent a therapeutic target. However, the development of strategies to block BAG3 function in cancer cells may be challenging, as they are likely to interfere with the essential roles of BAG3 in the heart. In this Review, we present the current knowledge regarding the biology of this complex protein in the heart and in cancer and suggest several therapeutic options.
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Affiliation(s)
- Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, USA
| | - Joseph Y Cheung
- Division of Renal Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Arthur M Feldman
- Department of Medicine, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
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9
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Overexpression of human BAG3 P209L in mice causes restrictive cardiomyopathy. Nat Commun 2021; 12:3575. [PMID: 34117258 PMCID: PMC8196106 DOI: 10.1038/s41467-021-23858-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 05/20/2021] [Indexed: 12/15/2022] Open
Abstract
An amino acid exchange (P209L) in the HSPB8 binding site of the human co-chaperone BAG3 gives rise to severe childhood cardiomyopathy. To phenocopy the disease in mice and gain insight into its mechanisms, we generated humanized transgenic mouse models. Expression of human BAG3P209L-eGFP in mice caused Z-disc disintegration and formation of protein aggregates. This was accompanied by massive fibrosis resulting in early-onset restrictive cardiomyopathy with increased mortality as observed in patients. RNA-Seq and proteomics revealed changes in the protein quality control system and increased autophagy in hearts from hBAG3P209L-eGFP mice. The mutation renders hBAG3P209L less soluble in vivo and induces protein aggregation, but does not abrogate hBAG3 binding properties. In conclusion, we report a mouse model mimicking the human disease. Our data suggest that the disease mechanism is due to accumulation of hBAG3P209L and mouse Bag3, causing sequestering of components of the protein quality control system and autophagy machinery leading to sarcomere disruption. An amino acid exchange (P209L) in the human co-chaperone BAG3 gives rise to severe childhood restrictive cardiomyopathy. Here the authors describe humanized transgenic mouse models which phenocopy the disease and provide insight into the pathogenic mechanisms.
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10
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Martin TG, Myers VD, Dubey P, Dubey S, Perez E, Moravec CS, Willis MS, Feldman AM, Kirk JA. Cardiomyocyte contractile impairment in heart failure results from reduced BAG3-mediated sarcomeric protein turnover. Nat Commun 2021; 12:2942. [PMID: 34011988 PMCID: PMC8134551 DOI: 10.1038/s41467-021-23272-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 04/22/2021] [Indexed: 12/22/2022] Open
Abstract
The association between reduced myofilament force-generating capacity (Fmax) and heart failure (HF) is clear, however the underlying molecular mechanisms are poorly understood. Here, we show impaired Fmax arises from reduced BAG3-mediated sarcomere turnover. Myofilament BAG3 expression decreases in human HF and positively correlates with Fmax. We confirm this relationship using BAG3 haploinsufficient mice, which display reduced Fmax and increased myofilament ubiquitination, suggesting impaired protein turnover. We show cardiac BAG3 operates via chaperone-assisted selective autophagy (CASA), conserved from skeletal muscle, and confirm sarcomeric CASA complex localization is BAG3/proteotoxic stress-dependent. Using mass spectrometry, we characterize the myofilament CASA interactome in the human heart and identify eight clients of BAG3-mediated turnover. To determine if increasing BAG3 expression in HF can restore sarcomere proteostasis/Fmax, HF mice were treated with rAAV9-BAG3. Gene therapy fully rescued Fmax and CASA protein turnover after four weeks. Our findings indicate BAG3-mediated sarcomere turnover is fundamental for myofilament functional maintenance. Decreased expression of BAG3 in the heart is associated with contractile dysfunction and heart failure. Here the authors show that this is due to decreased BAG3-dependent sarcomere protein turnover, which impairs mechanical function, and that sarcomere force-generating capacity is restored with BAG3 gene therapy.
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Affiliation(s)
- Thomas G Martin
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL, USA
| | - Valerie D Myers
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Praveen Dubey
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Shubham Dubey
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Edith Perez
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL, USA
| | - Christine S Moravec
- Department of Medicine, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, USA
| | - Monte S Willis
- Department of Pathology and Laboratory Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Arthur M Feldman
- Department of Medicine, Temple University Lewis Katz School of Medicine, Philadelphia, PA, USA
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, IL, USA.
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11
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BAG3 Myopathy Presenting With Prominent Neuropathic Phenotype and No Cardiac or Respiratory Involvement: A Case Report and Literature Review. J Clin Neuromuscul Dis 2021; 21:230-239. [PMID: 32453099 DOI: 10.1097/cnd.0000000000000300] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Bcl-2-associated athanogene 3 (BAG3) myopathy is a rare myofibrillar myopathy characterized by toe walking and clumsiness in the first decade with rapid progression to cardiomyopathy and restrictive lung disease in the second decade. Most patients (18 patients) have the c.626C >T (p.Pro209Leu) mutation. We describe BAG3 myopathy due to p.Pro209Leu in a 13-year-old girl with initial prominent neuropathic phenotype and no cardiac or respiratory involvement. Parents reported toe walking and clumsiness since 3 years old. Examination at the age of 13 years showed findings suggestive of Charcot-Marie-Tooth disease. Nerve conduction studies revealed demyelinating polyneuropathy. Next-generation sequencing panel for inherited neuropathies was unrevealing. Whole exome sequencing identified a de novo mutation in BAG3. Muscle biopsy confirmed myofibrillar myopathy. No cardiac involvement or symptoms of respiratory involvement at the age of 14 years. This case emphasizes the phenotypic variability of BAG3 myopathy and the importance of thorough electrophysiological examination and muscle pathology for establishing a precise diagnosis.
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12
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Bogomolovas J, Feng W, Yu MD, Huang S, Zhang L, Trexler C, Gu Y, Spinozzi S, Chen J. Atypical ALPK2 kinase is not essential for cardiac development and function. Am J Physiol Heart Circ Physiol 2020; 318:H1509-H1515. [PMID: 32383995 PMCID: PMC7311700 DOI: 10.1152/ajpheart.00249.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 04/28/2020] [Accepted: 05/05/2020] [Indexed: 01/18/2023]
Abstract
Protein kinases play an integral role in cardiac development, function, and disease. Recent experimental and clinical data have implied that protein kinases belonging to a family of atypical α-protein kinases, including α-protein kinase 2 (ALPK2), are important for regulating cardiac development and maintaining function via regulation of WNT signaling. A recent study in zebrafish reported that loss of ALPK2 leads to severe cardiac defects; however, the relevance of ALPK2 has not been studied in a mammalian animal model. To assess the role of ALPK2 in the mammalian heart, we generated two independent global Alpk2-knockout (Alpk2-gKO) mouse lines, using CRISPR/Cas9 technology. We performed physiological and biochemical analyses of Alpk2-gKO mice to determine the functional, morphological, and molecular consequences of Alpk2 deletion at the organismal level. We found that Alpk2-gKO mice exhibited normal cardiac function and morphology up to one year of age. Moreover, we did not observe altered WNT signaling in neonatal Alpk2-gKO mouse hearts. In conclusion, Alpk2 is dispensable for cardiac development and function in the murine model. Our results suggest that Alpk2 is a rapidly evolving gene that lost its essential cardiac functions in mammals.NEW & NOTEWORTHY Several studies indicated the importance of ALPK2 for cardiac function and development. A recent study in zebrafish report that loss of ALPK2 leads to severe cardiac defects. In contrast, murine Alpk2-gKO models developed in this work display no overt cardiac phenotype. Our results suggest ALPK2, as a rapidly evolving gene, lost its essential cardiac functions in mammals.
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Affiliation(s)
- Julius Bogomolovas
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Wei Feng
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Matthew Daniel Yu
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Serena Huang
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Lunfeng Zhang
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Christa Trexler
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Yusu Gu
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Simone Spinozzi
- Department of Medicine, University of California, San Diego, La Jolla, California
| | - Ju Chen
- Department of Medicine, University of California, San Diego, La Jolla, California
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13
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BAG3 Pro209 mutants associated with myopathy and neuropathy relocate chaperones of the CASA-complex to aggresomes. Sci Rep 2020; 10:8755. [PMID: 32472079 PMCID: PMC7260189 DOI: 10.1038/s41598-020-65664-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 05/07/2020] [Indexed: 12/31/2022] Open
Abstract
Three missense mutations targeting the same proline 209 (Pro209) codon in the co-chaperone Bcl2-associated athanogene 3 (BAG3) have been reported to cause distal myopathy, dilated cardiomyopathy or Charcot-Marie-Tooth type 2 neuropathy. Yet, it is unclear whether distinct molecular mechanisms underlie the variable clinical spectrum of the rare patients carrying these three heterozygous Pro209 mutations in BAG3. Here, we studied all three variants and compared them to the BAG3_Glu455Lys mutant, which causes dilated cardiomyopathy. We found that all BAG3_Pro209 mutants have acquired a toxic gain-of-function, which causes these variants to accumulate in the form of insoluble HDAC6- and vimentin-positive aggresomes. The aggresomes formed by mutant BAG3 led to a relocation of other chaperones such as HSPB8 and Hsp70, which, together with BAG3, promote the so-called chaperone-assisted selective autophagy (CASA). As a consequence of their increased aggregation-proneness, mutant BAG3 trapped ubiquitinylated client proteins at the aggresome, preventing their efficient clearance. Combined, these data show that all BAG3_Pro209 mutants, irrespective of their different clinical phenotypes, are characterized by a gain-of-function that contributes to the gradual loss of protein homeostasis.
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Yang F, Huang L, Tso A, Wang H, Cui L, Lin L, Wang X, Ren M, Fang X, Liu J, Han Z, Chen J, Ouyang K. Inositol 1,4,5-trisphosphate receptors are essential for fetal-maternal connection and embryo viability. PLoS Genet 2020; 16:e1008739. [PMID: 32320395 PMCID: PMC7176088 DOI: 10.1371/journal.pgen.1008739] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/25/2020] [Indexed: 01/28/2023] Open
Abstract
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are a family of intracellular Ca2+ release channels located on the ER membrane, which in mammals consist of 3 different subtypes (IP3R1, IP3R2, and IP3R3) encoded by 3 genes, Itpr1, Itpr2, and Itpr3, respectively. Studies utilizing genetic knockout mouse models have demonstrated that IP3Rs are essential for embryonic survival in a redundant manner. Deletion of both IP3R1 and IP3R2 has been shown to cause cardiovascular defects and embryonic lethality. However, it remains unknown which cell types account for the cardiovascular defects in IP3R1 and IP3R2 double knockout (DKO) mice. In this study, we generated conditional IP3R1 and IP3R2 knockout mouse models with both genes deleted in specific cardiovascular cell lineages. Our results revealed that deletion of IP3R1 and IP3R2 in cardiomyocytes by TnT-Cre, in endothelial / hematopoietic cells by Tie2-Cre and Flk1-Cre, or in early precursors of the cardiovascular lineages by Mesp1-Cre, resulted in no phenotypes. This demonstrated that deletion of both IP3R genes in cardiovascular cell lineages cannot account for the cardiovascular defects and embryonic lethality observed in DKO mice. We then revisited and performed more detailed phenotypic analysis in DKO embryos, and found that DKO embryos developed cardiovascular defects including reduced size of aortas, enlarged cardiac chambers, as well as growth retardation at embryonic day (E) 9.5, but in varied degrees of severity. Interestingly, we also observed allantoic-placental defects including reduced sizes of umbilical vessels and reduced depth of placental labyrinth in DKO embryos, which could occur independently from other phenotypes in DKO embryos even without obvious growth retardation. Furthermore, deletion of both IP3R1 and IP3R2 by the epiblast-specific Meox2-Cre, which targets all the fetal tissues and extraembryonic mesoderm but not extraembryonic trophoblast cells, also resulted in embryonic lethality and similar allantoic-placental defects. Taken together, our results demonstrated that IP3R1 and IP3R2 play an essential and redundant role in maintaining the integrity of fetal-maternal connection and embryonic viability.
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Affiliation(s)
- Feili Yang
- School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Lei Huang
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, Shenzhen, China
| | - Alexandria Tso
- University of California San Diego, School of Medicine, Department of Medicine, La Jolla, CA, United States of America
| | - Hong Wang
- School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
| | - Li Cui
- University of California San Diego, School of Medicine, Department of Medicine, La Jolla, CA, United States of America
| | - Lizhu Lin
- University of California San Diego, School of Medicine, Department of Medicine, La Jolla, CA, United States of America
| | - Xiaohong Wang
- Department of Pharmacology, Tianjin Key Laboratory of Inflammation Biology, School of Basic Medical Sciences, Tianjin Medical University, Tianjin, China
| | - Mingming Ren
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, Shenzhen, China
| | - Xi Fang
- University of California San Diego, School of Medicine, Department of Medicine, La Jolla, CA, United States of America
| | - Jie Liu
- Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen, China
| | - Zhen Han
- Department of Cardiovascular Surgery, Peking University Shenzhen Hospital, Shenzhen, China
- * E-mail: (ZH); (JC); (KO)
| | - Ju Chen
- University of California San Diego, School of Medicine, Department of Medicine, La Jolla, CA, United States of America
- * E-mail: (ZH); (JC); (KO)
| | - Kunfu Ouyang
- School of Chemical Biology and Biotechnology, State Key Laboratory of Chemical Oncogenomics, Peking University Shenzhen Graduate School, Shenzhen, China
- * E-mail: (ZH); (JC); (KO)
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15
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Neuromuscular Diseases Due to Chaperone Mutations: A Review and Some New Results. Int J Mol Sci 2020; 21:ijms21041409. [PMID: 32093037 PMCID: PMC7073051 DOI: 10.3390/ijms21041409] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 02/12/2020] [Accepted: 02/13/2020] [Indexed: 12/12/2022] Open
Abstract
Skeletal muscle and the nervous system depend on efficient protein quality control, and they express chaperones and cochaperones at high levels to maintain protein homeostasis. Mutations in many of these proteins cause neuromuscular diseases, myopathies, and hereditary motor and sensorimotor neuropathies. In this review, we cover mutations in DNAJB6, DNAJB2, αB-crystallin (CRYAB, HSPB5), HSPB1, HSPB3, HSPB8, and BAG3, and discuss the molecular mechanisms by which they cause neuromuscular disease. In addition, previously unpublished results are presented, showing downstream effects of BAG3 p.P209L on DNAJB6 turnover and localization.
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Robertson R, Conte TC, Dicaire MJ, Rymar VV, Sadikot AF, Bryson-Richardson RJ, Lavoie JN, O'Ferrall E, Young JC, Brais B. BAG3 P215L/KO Mice as a Model of BAG3 P209L Myofibrillar Myopathy. THE AMERICAN JOURNAL OF PATHOLOGY 2020; 190:554-562. [PMID: 31953038 DOI: 10.1016/j.ajpath.2019.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Revised: 11/22/2019] [Accepted: 11/26/2019] [Indexed: 10/25/2022]
Abstract
BCL-2-associated athanogene 3 (BAG3) is a co-chaperone to heat shock proteins important in degrading misfolded proteins through chaperone-assisted selective autophagy. The recurrent dominant BAG3-P209L mutation results in a severe childhood-onset myofibrillar myopathy (MFM) associated with progressive muscle weakness, cardiomyopathy, and respiratory failure. Because a homozygous knock-in (KI) strain for the mP215L mutation homologous to the human P209L mutation did not have a gross phenotype, compound heterozygote knockout (KO) and KI mP215L mice were generated to establish whether further reduction in BAG3 expression would lead to a phenotype. The KI/KO mice have a significant decrease in voluntary movement compared with wild-type and KI/KI mice in the open field starting at 7 months. The KI/KI and KI/KO mice both have significantly smaller muscle fiber cross-sectional area. However, only the KI/KO mice have clear skeletal muscle histologic changes in MFM. As in patient muscle, there are increased levels of BAG3-interacting proteins, such as p62, heat shock protein B8, and αB-crystallin. The KI/KO mP215L strain is the first murine model of BAG3 myopathy that resembles the human skeletal muscle pathologic features. The results support the hypothesis that the pathologic development of MFM requires a significant decrease in BAG3 protein level and not only a gain of function caused by the dominant missense mutation.
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Affiliation(s)
- Rebecca Robertson
- Neurogenetics of Motion Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Talita C Conte
- Neurogenetics of Motion Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada; Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Marie-Josée Dicaire
- Neurogenetics of Motion Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Vladimir V Rymar
- Cone Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Abbas F Sadikot
- Cone Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | | | - Josée N Lavoie
- Centre de Recherche sur le Cancer, l'Université Laval, Québec, Quebec, Canada; Oncology Axis, Centre de Recherche du Centre Hospitalier Universitaire (CHU), Québec-Université Laval, Québec, Quebec, Canada; Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, l'Université Laval, Québec, Quebec, Canada
| | - Erin O'Ferrall
- Rare Neurological Diseases Group, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - Jason C Young
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
| | - Bernard Brais
- Neurogenetics of Motion Laboratory, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada.
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17
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Abstract
The B cell lymphoma 2-associated anthanogene (BAG3) is an anti-apoptotic co-chaperone protein. Previous reports suggest that mutations in BAG3 are associated with dilated cardiomyopathy. This review aims to summarize the current understanding of the relationship between BAG3 mutations and dilated cardiomyopathy, primarily focusing on the role and protective mechanism of BAG3 in cardiomyocytes from individuals with dilated cardiomyopathy. The results of published studies show that BAG3 is critically important for reducing cardiomyocyte apoptosis, maintaining protein homeostasis, regulating mitochondrial stability, modulating myocardial contraction, and reducing cardiac arrhythmia, which suggests an indispensable protective mechanism of BAG3 in dilated cardiomyopathy. The significant role of BAG3 in protecting cardiomyocytes provides a new direction for the diagnosis and treatment of dilated cardiomyopathy. However, further research is required to explore the molecular mechanisms that regulate BAG3 expression, to identify a novel therapy for patients with dilated cardiomyopathy.
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