1
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Martin TG, Sherer LA, Kirk JA. BAG3 localizes to mitochondria in cardiac fibroblasts and regulates mitophagy. Am J Physiol Heart Circ Physiol 2024; 326:H1124-H1130. [PMID: 38488519 DOI: 10.1152/ajpheart.00736.2023] [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: 11/21/2023] [Revised: 03/01/2024] [Accepted: 03/08/2024] [Indexed: 04/14/2024]
Abstract
The co-chaperone Bcl2-associated athanogene 3 (BAG3) is a central node in protein quality control in the heart. In humans and animal models, decreased BAG3 expression is associated with cardiac dysfunction and dilated cardiomyopathy. Although previous studies focused on BAG3 in cardiomyocytes, cardiac fibroblasts are also critical drivers of pathologic remodeling. Yet, the role of BAG3 in cardiac fibroblasts is almost completely unexplored. Here, we show that BAG3 is expressed in primary rat neonatal cardiac fibroblasts and preferentially localizes to mitochondria. Knockdown of BAG3 reduces mitophagy and enhances fibroblast activation, which is associated with fibrotic remodeling. Heat shock protein 70 (Hsp70) is a critical binding partner for BAG3 and inhibiting this interaction in fibroblasts using the drug JG-98 decreased autophagy, decreased mitofusin-2 expression, and disrupted mitochondrial morphology. Together, these data indicate that BAG3 is expressed in cardiac fibroblasts, where it facilitates mitophagy and promotes fibroblast quiescence. This suggests that depressed BAG3 levels in heart failure may exacerbate fibrotic pathology, thus contributing to myocardial dysfunction through sarcomere-independent pathways.NEW & NOTEWORTHY We report BAG3's localization to mitochondria and its role in mitophagy for the first time in primary ventricular cardiac fibroblasts. We have also collected the first evidence showing that loss of BAG3 increases cardiac fibroblast activation into myofibroblasts, which are major drivers of cardiac fibrosis and pathological remodeling during heart disease.
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Affiliation(s)
- Thomas G Martin
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, Illinois, United States
| | - Laura A Sherer
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, Illinois, United States
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Stritch School of Medicine, Maywood, Illinois, United States
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2
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Joutsen J, Pessa JC, Jokelainen O, Sironen R, Hartikainen JM, Sistonen L. Comprehensive analysis of human tissues reveals unique expression and localization patterns of HSF1 and HSF2. Cell Stress Chaperones 2024; 29:235-271. [PMID: 38458311 PMCID: PMC10963207 DOI: 10.1016/j.cstres.2024.03.001] [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: 01/25/2024] [Revised: 02/29/2024] [Accepted: 03/01/2024] [Indexed: 03/10/2024] Open
Abstract
Heat shock factors (HSFs) are the main transcriptional regulators of the evolutionarily conserved heat shock response. Beyond cell stress, several studies have demonstrated that HSFs also contribute to a vast variety of human pathologies, ranging from metabolic diseases to cancer and neurodegeneration. Despite their evident role in mitigating cellular perturbations, the functions of HSF1 and HSF2 in physiological proteostasis have remained inconclusive. Here, we analyzed a comprehensive selection of paraffin-embedded human tissue samples with immunohistochemistry. We demonstrate that both HSF1 and HSF2 display distinct expression and subcellular localization patterns in benign tissues. HSF1 localizes to the nucleus in all epithelial cell types, whereas nuclear expression of HSF2 was limited to only a few cell types, especially the spermatogonia and the urothelial umbrella cells. We observed a consistent and robust cytoplasmic expression of HSF2 across all studied smooth muscle and endothelial cells, including the smooth muscle cells surrounding the vasculature and the high endothelial venules in lymph nodes. Outstandingly, HSF2 localized specifically at cell-cell adhesion sites in a broad selection of tissue types, such as the cardiac muscle, liver, and epididymis. To the best of our knowledge, this is the first study to systematically describe the expression and localization patterns of HSF1 and HSF2 in benign human tissues. Thus, our work expands the biological landscape of these factors and creates the foundation for the identification of specific roles of HSF1 and HSF2 in normal physiological processes.
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Affiliation(s)
- Jenny Joutsen
- Department of Pathology, Lapland Central Hospital, Lapland Wellbeing Services County, Rovaniemi, Finland.
| | - Jenny C Pessa
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland; Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland
| | - Otto Jokelainen
- Institute of Clinical Medicine, Clinical Pathology and Forensic Medicine, and Cancer RC, University of Eastern Finland, Kuopio, Finland; Department of Clinical Pathology, Kuopio University Hospital, Kuopio, Finland
| | - Reijo Sironen
- Institute of Clinical Medicine, Clinical Pathology and Forensic Medicine, and Cancer RC, University of Eastern Finland, Kuopio, Finland; Department of Clinical Pathology, Kuopio University Hospital, Kuopio, Finland
| | - Jaana M Hartikainen
- Institute of Clinical Medicine, Clinical Pathology and Forensic Medicine, and Cancer RC, University of Eastern Finland, Kuopio, Finland
| | - Lea Sistonen
- Faculty of Science and Engineering, Cell Biology, Åbo Akademi University, Turku, Finland; Turku Bioscience Centre, University of Turku and Åbo Akademi University, Turku, Finland.
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3
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Currie J, Manda V, Robinson SK, Lai C, Agnihotri V, Hidalgo V, Ludwig RW, Zhang K, Pavelka J, Wang ZV, Rhee JW, Lam MPY, Lau E. Simultaneous proteome localization and turnover analysis reveals spatiotemporal features of protein homeostasis disruptions. Nat Commun 2024; 15:2207. [PMID: 38467653 PMCID: PMC10928085 DOI: 10.1038/s41467-024-46600-5] [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: 05/01/2023] [Accepted: 02/20/2024] [Indexed: 03/13/2024] Open
Abstract
The spatial and temporal distributions of proteins are critical to protein function, but cannot be directly assessed by measuring protein bundance. Here we describe a mass spectrometry-based proteomics strategy, Simultaneous Proteome Localization and Turnover (SPLAT), to measure concurrently protein turnover rates and subcellular localization in the same experiment. Applying the method, we find that unfolded protein response (UPR) has different effects on protein turnover dependent on their subcellular location in human AC16 cells, with proteome-wide slowdown but acceleration among stress response proteins in the ER and Golgi. In parallel, UPR triggers broad differential localization of proteins including RNA-binding proteins and amino acid transporters. Moreover, we observe newly synthesized proteins including EGFR that show a differential localization under stress than the existing protein pools, reminiscent of protein trafficking disruptions. We next applied SPLAT to an induced pluripotent stem cell derived cardiomyocyte (iPSC-CM) model of cancer drug cardiotoxicity upon treatment with the proteasome inhibitor carfilzomib. Paradoxically, carfilzomib has little effect on global average protein half-life, but may instead selectively disrupt sarcomere protein homeostasis. This study provides a view into the interactions of protein spatial and temporal dynamics and demonstrates a method to examine protein homeostasis regulations in stress and drug response.
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Affiliation(s)
- Jordan Currie
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Vyshnavi Manda
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Sean K Robinson
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Celine Lai
- Stanford Cardiovascular Institute, Stanford University, Stanford, CA, 94305, USA
| | - Vertica Agnihotri
- Department of Medicine, Division of Cardiology, City of Hope Comprehensive Cancer Center, CA, 91010, Duarte, USA
| | - Veronica Hidalgo
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - R W Ludwig
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Kai Zhang
- Department of Diabetes and Cancer Metabolism, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, 91010, USA
| | - Jay Pavelka
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Zhao V Wang
- Department of Diabetes and Cancer Metabolism, Beckman Research Institute, City of Hope National Medical Center, Duarte, CA, 91010, USA
| | - June-Wha Rhee
- Department of Medicine, Division of Cardiology, City of Hope Comprehensive Cancer Center, CA, 91010, Duarte, USA
| | - Maggie P Y Lam
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, Aurora, CO, 80045, USA
- Consortium for Fibrosis Research and Translation, University of Colorado School of Medicine, Aurora, CO, 80045, USA
| | - Edward Lau
- Department of Medicine, University of Colorado School of Medicine, Aurora, CO, 80045, USA.
- Consortium for Fibrosis Research and Translation, University of Colorado School of Medicine, Aurora, CO, 80045, USA.
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4
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Jones TLM, Woulfe KC. Considering impact of age and sex on cardiac cytoskeletal components. Am J Physiol Heart Circ Physiol 2024; 326:H470-H478. [PMID: 38133622 PMCID: PMC11219061 DOI: 10.1152/ajpheart.00619.2023] [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: 10/02/2023] [Revised: 12/08/2023] [Accepted: 12/21/2023] [Indexed: 12/23/2023]
Abstract
The cardiac cytoskeletal components are integral to cardiomyocyte function and are responsible for contraction, sustaining cell structure, and providing scaffolding to direct signaling. Cytoskeletal components have been implicated in cardiac pathology; however, less attention has been paid to age-related modifications of cardiac cytoskeletal components and how these contribute to dysfunction with increased age. Moreover, significant sex differences in cardiac aging have been identified, but we still lack a complete understanding to the mechanisms behind these differences. This review summarizes what is known about how key cardiomyocyte cytoskeletal components are modified because of age, as well as reported sex-specific differences. Thorough consideration of both age and sex as integral players in cytoskeletal function may reveal potential avenues for more personalized therapeutics.
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Affiliation(s)
- Timothy L M Jones
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Kathleen C Woulfe
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
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5
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Martin TG, Pak H, Gerhard GS, Merali S, Merali C, Lemster B, Dubey P, McTiernan CF, Bristow MR, Feldman AM, Kirk JA. Dysregulated Autophagy and Sarcomere Dysfunction in Patients With Heart Failure With Co-Occurrence of P63A and P380S BAG3 Variants. J Am Heart Assoc 2023; 12:e029938. [PMID: 38108245 PMCID: PMC10863766 DOI: 10.1161/jaha.123.029938] [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: 02/21/2023] [Accepted: 11/15/2023] [Indexed: 12/19/2023]
Abstract
BACKGROUND Mutations to the co-chaperone protein BAG3 (B-cell lymphoma-2-associated athanogene-3) are a leading cause of dilated cardiomyopathy (DCM). These mutations often impact the C-terminal BAG domain (residues 420-499), which regulates heat shock protein 70-dependent protein turnover via autophagy. While mutations in other regions are less common, previous studies in patients with DCM found that co-occurrence of 2 BAG3 variants (P63A, P380S) led to worse prognosis. However, the underlying mechanism for dysfunction is not fully understood. METHODS AND RESULTS In this study, we used proteomics, Western blots, and myofilament functional assays on left ventricular tissue from patients with nonfailing, DCM, and DCM with BAG363/380 to determine how these mutations impact protein quality control and cardiomyocyte contractile function. We found dysregulated autophagy and increased protein ubiquitination in patients with BAG363/380 compared with nonfailing and DCM, suggesting impaired protein turnover. Expression and myofilament localization of BAG3-binding proteins were also uniquely altered in the BAG3,63/380 including abolished localization of the small heat shock protein CRYAB (alpha-crystallin B chain) to the sarcomere. To determine whether these variants impacted sarcomere function, we used cardiomyocyte force-calcium assays and found reduced maximal calcium-activated force in DCM and BAG363/380. Interestingly, myofilament calcium sensitivity was increased in DCM but not with BAG363/380, which was not explained by differences in troponin I phosphorylation. CONCLUSIONS Together, our data support that the disease-enhancing mechanism for BAG3 variants outside of the BAG domain is through disrupted protein turnover leading to compromised sarcomere function. These findings suggest a shared mechanism of disease among pathogenic BAG3 variants, regardless of location.
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Affiliation(s)
- Thomas G. Martin
- Department of Cell and Molecular PhysiologyLoyola University Chicago Stritch School of MedicineMaywoodIL
| | - Hana Pak
- Department of Cell and Molecular PhysiologyLoyola University Chicago Stritch School of MedicineMaywoodIL
| | - Glenn S. Gerhard
- Department of Medical Genetics and Molecular BiochemistryLewis Katz School of Medicine of Temple UniversityPhiladelphiaPA
| | - Salim Merali
- Temple University School of PharmacyPhiladelphiaPA
| | | | - Bonnie Lemster
- The Heart and Vascular Institute, The University of Pittsburgh School of MedicinePittsburghPA
| | - Praveen Dubey
- Department of Biomedical EngineeringUniversity of Alabama at BirminghamBirminghamAL
| | - Charles F. McTiernan
- The Heart and Vascular Institute, The University of Pittsburgh School of MedicinePittsburghPA
| | | | - Arthur M. Feldman
- Department of Medicine, Division of CardiologyThe Lewis Katz School of Medicine at Temple UniversityPhiladelphiaPA
| | - Jonathan A. Kirk
- Department of Cell and Molecular PhysiologyLoyola University Chicago Stritch School of MedicineMaywoodIL
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6
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Thompson AD, Wagner MJ, Rodriguez J, Malhotra A, Vander Roest S, Lilienthal U, Shao H, Vignesh M, Weber K, Yob JM, Prosser BL, Helms AS, Gestwicki JE, Ginsburg D, Day SM. An Unbiased Screen Identified the Hsp70-BAG3 Complex as a Regulator of Myosin-Binding Protein C3. JACC Basic Transl Sci 2023; 8:1198-1211. [PMID: 37791314 PMCID: PMC10544073 DOI: 10.1016/j.jacbts.2023.04.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 04/17/2023] [Accepted: 04/18/2023] [Indexed: 10/05/2023]
Abstract
Variants in the gene myosin-binding protein C3 (MYBPC3) account for approximately 50% of familial hypertrophic cardiomyopathy (HCM), leading to reduced levels of myosin-binding protein C3 (MyBP-C), the protein product made by gene MYBPC3. Elucidation of the pathways that regulate MyBP-C protein homeostasis could uncover new therapeutic strategies. Toward this goal, we screened a library of 2,426 bioactive compounds and identified JG98, an allosteric modulator of heat shock protein 70 that inhibits interaction with Bcl-2-associated athanogene (BAG) domain co-chaperones. JG98 reduces MyBP-C protein levels. Furthermore, genetic reduction of BAG3 phenocopies treatment with JG-98 by reducing MYBP-C protein levels.. Thus, an unbiased compound screen identified the heat shock protein 70-BAG3 complex as a regulator of MyBP-C stability.
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Affiliation(s)
- Andrea D. Thompson
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Marcus J. Wagner
- Department of Internal Medicine, Division of Cardiovascular Medicine and Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Juliani Rodriguez
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Alok Malhotra
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Steve Vander Roest
- Center for Chemical Genomics, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Ulla Lilienthal
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Hao Shao
- Institute for Neurodegenerative Diseases and Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - Mathav Vignesh
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Keely Weber
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Jaime M. Yob
- Department of Internal Medicine, Division of Cardiovascular Medicine and Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Benjamin L. Prosser
- Department of Physiology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Adam S. Helms
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Jason E. Gestwicki
- Institute for Neurodegenerative Diseases and Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, USA
| | - David Ginsburg
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
- Department of Pediatrics, University of Michigan, Ann Arbor, Michigan, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
- The Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
| | - Sharlene M. Day
- Department of Internal Medicine, Division of Cardiovascular Medicine and Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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7
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Martin TG, Juarros MA, Cleveland JC, Bristow MR, Ambardekar AV, Buttrick PM, Leinwand LA. Assessment of Autophagy Markers Suggests Increased Activity Following LVAD Therapy. JACC Basic Transl Sci 2023; 8:1043-1056. [PMID: 37791310 PMCID: PMC10544085 DOI: 10.1016/j.jacbts.2023.05.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 10/05/2023]
Abstract
Left ventricular reverse remodeling in heart failure is associated with improved clinical outcomes. However, the molecular features that drive this process are poorly defined. Left ventricular assist devices (LVADs) are the therapy associated with the greatest reverse remodeling and lead to partial myocardial recovery in most patients. In this study, we examined whether autophagy may be implicated in post-LVAD reverse remodeling. We found expression of key autophagy factors increased post-LVAD, while autophagic substrates decreased. Autolysosome numbers increased post-LVAD, further indicating increased autophagy. These findings support the conclusion that mechanical unloading activates autophagy, which may underly the reverse remodeling observed.
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Affiliation(s)
- Thomas G. Martin
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, USA
| | - Miranda A. Juarros
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, USA
| | - Joseph C. Cleveland
- Department of Surgery, Division of Cardiothoracic Surgery, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Michael R. Bristow
- Department of Medicine, Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Amrut V. Ambardekar
- Department of Medicine, Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Peter M. Buttrick
- Department of Medicine, Division of Cardiology, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Leslie A. Leinwand
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, USA
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8
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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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9
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Brenner CM, Choudhary M, McCormick MG, Cheung D, Landesberg GP, Wang JF, Song J, Martin TG, Cheung JY, Qu HQ, Hakonarson H, Feldman AM. BAG3: Nature's Quintessential Multi-Functional Protein Functions as a Ubiquitous Intra-Cellular Glue. Cells 2023; 12:937. [PMID: 36980278 PMCID: PMC10047307 DOI: 10.3390/cells12060937] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 03/30/2023] Open
Abstract
BAG3 is a 575 amino acid protein that is found throughout the animal kingdom and homologs have been identified in plants. The protein is expressed ubiquitously but is most prominent in cardiac muscle, skeletal muscle, the brain and in many cancers. We describe BAG3 as a quintessential multi-functional protein. It supports autophagy of both misfolded proteins and damaged organelles, inhibits apoptosis, maintains the homeostasis of the mitochondria, and facilitates excitation contraction coupling through the L-type calcium channel and the beta-adrenergic receptor. High levels of BAG3 are associated with insensitivity to chemotherapy in malignant cells whereas both loss of function and gain of function variants are associated with cardiomyopathy.
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Affiliation(s)
- Caitlyn M. Brenner
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
| | - Muaaz Choudhary
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
| | - Michael G. McCormick
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - David Cheung
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Gavin P. Landesberg
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Ju-Fang Wang
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Jianliang Song
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Thomas G. Martin
- Department of Molecular, Cellular and Developmental Biology, Colorado University School of Medicine, Aurora, CO 80045, USA
| | - Joseph Y. Cheung
- Division of Renal Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Hui-Qi Qu
- Center for Applied Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 191104, USA
| | - Hakon Hakonarson
- Center for Applied Genomics, Children’s Hospital of Philadelphia, Philadelphia, PA 191104, USA
- Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 191104, USA
- Division of Human Genetics and Division of Pulmonary Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 191104, USA
- Department of Pediatrics, Division of Human Genetics and Division of Pulmonary Medicine, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 191104, USA
| | - Arthur M. Feldman
- Department of Medicine, Division of Cardiology, Lewis Katz School of Medicine at Temple University, 3500 N. Broad Street, MERB 752, Philadelphia, PA 19140, USA; (C.M.B.); (M.C.)
- Center for Neurovirology and Gene Editing, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
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Fairweather D, Beetler DJ, Musigk N, Heidecker B, Lyle MA, Cooper LT, Bruno KA. Sex and gender differences in myocarditis and dilated cardiomyopathy: An update. Front Cardiovasc Med 2023; 10:1129348. [PMID: 36937911 PMCID: PMC10017519 DOI: 10.3389/fcvm.2023.1129348] [Citation(s) in RCA: 37] [Impact Index Per Article: 37.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 02/06/2023] [Indexed: 03/06/2023] Open
Abstract
In the past decade there has been a growing interest in understanding sex and gender differences in myocarditis and dilated cardiomyopathy (DCM), and the purpose of this review is to provide an update on this topic including epidemiology, pathogenesis and clinical presentation, diagnosis and management. Recently, many clinical studies have been conducted examining sex differences in myocarditis. Studies consistently report that myocarditis occurs more often in men than women with a sex ratio ranging from 1:2-4 female to male. Studies reveal that DCM also has a sex ratio of around 1:3 women to men and this is also true for familial/genetic forms of DCM. Animal models have demonstrated that DCM develops after myocarditis in susceptible mouse strains and evidence exists for this progress clinically as well. A consistent finding is that myocarditis occurs primarily in men under 50 years of age, but in women after age 50 or post-menopause. In contrast, DCM typically occurs after age 50, although the age that post-myocarditis DCM occurs has not been investigated. In a small study, more men with myocarditis presented with symptoms of chest pain while women presented with dyspnea. Men with myocarditis have been found to have higher levels of heart failure biomarkers soluble ST2, creatine kinase, myoglobin and T helper 17-associated cytokines while women develop a better regulatory immune response. Studies of the pathogenesis of disease have found that Toll-like receptor (TLR)2 and TLR4 signaling pathways play a central role in increasing inflammation during myocarditis and in promoting remodeling and fibrosis that leads to DCM, and all of these pathways are elevated in males. Management of myocarditis follows heart failure guidelines and there are currently no disease-specific therapies. Research on standard heart failure medications reveal important sex differences. Overall, many advances in our understanding of the effect of biologic sex on myocarditis and DCM have occurred over the past decade, but many gaps in our understanding remain. A better understanding of sex and gender effects are needed to develop disease-targeted and individualized medicine approaches in the future.
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Affiliation(s)
- DeLisa Fairweather
- Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, FL, United States
- Department of Environmental Health Sciences and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States
- Center for Clinical and Translational Science, Mayo Clinic, Rochester, MN, United States
| | - Danielle J. Beetler
- Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, FL, United States
- Center for Clinical and Translational Science, Mayo Clinic, Rochester, MN, United States
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Jacksonville, FL, United States
| | - Nicolas Musigk
- Department of Cardiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Bettina Heidecker
- Department of Cardiology, Charité – Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Melissa A. Lyle
- Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, FL, United States
| | - Leslie T. Cooper
- Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, FL, United States
| | - Katelyn A. Bruno
- Department of Cardiovascular Medicine, Mayo Clinic, Jacksonville, FL, United States
- Division of Cardiovascular Medicine, Department of Medicine, University of Florida, Gainesville, FL, United States
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11
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Machine learning and bioinformatics to identify 8 autophagy-related biomarkers and construct gene regulatory networks in dilated cardiomyopathy. Sci Rep 2022; 12:15030. [PMID: 36056063 PMCID: PMC9440113 DOI: 10.1038/s41598-022-19027-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Accepted: 08/23/2022] [Indexed: 11/29/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a condition of impaired ventricular remodeling and systolic diastole that is often complicated by arrhythmias and heart failure with a poor prognosis. This study attempted to identify autophagy-related genes (ARGs) with diagnostic biomarkers of DCM using machine learning and bioinformatics approaches. Differential analysis of whole gene microarray data of DCM from the Gene Expression Omnibus (GEO) database was performed using the NetworkAnalyst 3.0 platform. Differentially expressed genes (DEGs) matching (|log2FoldChange ≥ 0.8, p value < 0.05|) were obtained in the GSE4172 dataset by merging ARGs from the autophagy gene libraries, HADb and HAMdb, to obtain autophagy-related differentially expressed genes (AR-DEGs) in DCM. The correlation analysis of AR-DEGs and their visualization were performed using R language. Gene Ontology (GO) enrichment analysis and combined multi-database pathway analysis were served by the Enrichr online enrichment analysis platform. We used machine learning to screen the diagnostic biomarkers of DCM. The transcription factors gene regulatory network was constructed by the JASPAR database of the NetworkAnalyst 3.0 platform. We also used the drug Signatures database (DSigDB) drug database of the Enrichr platform to screen the gene target drugs for DCM. Finally, we used the DisGeNET database to analyze the comorbidities associated with DCM. In the present study, we identified 23 AR-DEGs of DCM. Eight (PLEKHF1, HSPG2, HSF1, TRIM65, DICER1, VDAC1, BAD, TFEB) molecular markers of DCM were obtained by two machine learning algorithms. Transcription factors gene regulatory network was established. Finally, 10 gene-targeted drugs and complications for DCM were identified.
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12
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Stress Reactivity, Susceptibility to Hypertension, and Differential Expression of Genes in Hypertensive Compared to Normotensive Patients. Int J Mol Sci 2022; 23:ijms23052835. [PMID: 35269977 PMCID: PMC8911431 DOI: 10.3390/ijms23052835] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/14/2022] [Accepted: 02/28/2022] [Indexed: 12/14/2022] Open
Abstract
Although half of hypertensive patients have hypertensive parents, known hypertension-related human loci identified by genome-wide analysis explain only 3% of hypertension heredity. Therefore, mainstream transcriptome profiling of hypertensive subjects addresses differentially expressed genes (DEGs) specific to gender, age, and comorbidities in accordance with predictive preventive personalized participatory medicine treating patients according to their symptoms, individual lifestyle, and genetic background. Within this mainstream paradigm, here, we determined whether, among the known hypertension-related DEGs that we could find, there is any genome-wide hypertension theranostic molecular marker applicable to everyone, everywhere, anytime. Therefore, we sequenced the hippocampal transcriptome of tame and aggressive rats, corresponding to low and high stress reactivity, an increase of which raises hypertensive risk; we identified stress-reactivity-related rat DEGs and compared them with their known homologous hypertension-related animal DEGs. This yielded significant correlations between stress reactivity-related and hypertension-related fold changes (log2 values) of these DEG homologs. We found principal components, PC1 and PC2, corresponding to a half-difference and half-sum of these log2 values. Using the DEGs of hypertensive versus normotensive patients (as the control), we verified the correlations and principal components. This analysis highlighted downregulation of β-protocadherins and hemoglobin as whole-genome hypertension theranostic molecular markers associated with a wide vascular inner diameter and low blood viscosity, respectively.
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Gupta MK, Randhawa PK, Masternak MM. Role of BAG5 in Protein Quality Control: Double-Edged Sword? FRONTIERS IN AGING 2022; 3:844168. [PMID: 35821856 PMCID: PMC9261338 DOI: 10.3389/fragi.2022.844168] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Accepted: 02/08/2022] [Indexed: 11/15/2022]
Abstract
Cardiovascular disorder is the major health burden and cause of death among individuals worldwide. As the cardiomyocytes lack the ability for self-renewal, it is utmost necessary to surveil the protein quality in the cells. The Bcl-2 associated anthanogene protein (BAG) family and molecular chaperones (HSP70, HSP90) actively participate in maintaining cellular protein quality control (PQC) to limit cellular dysfunction in the cells. The BAG family contains a unique BAG domain which facilitates their interaction with the ATPase domain of the heat shock protein 70 (HSP70) to assist in protein folding. Among the BAG family members (BAG1-6), BAG5 protein is unique since it has five domains in tandem, and the binding of BD5 induces certain conformational changes in the nucleotide-binding domain (NBD) of HSP70 such that it loses its affinity for binding to ADP and results in enhanced protein refolding activity of HSP70. In this review, we shall describe the role of BAG5 in modulating mitophagy, endoplasmic stress, and cellular viability. Also, we have highlighted the interaction of BAG5 with other proteins, including PINK, DJ-1, CHIP, and their role in cellular PQC. Apart from this, we have described the role of BAG5 in cellular metabolism and aging.
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Genotype-Phenotype Correlation in Familial BAG3 Mutation Dilated Cardiomyopathy. Genes (Basel) 2022; 13:genes13020363. [PMID: 35205406 PMCID: PMC8872048 DOI: 10.3390/genes13020363] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/11/2022] [Accepted: 02/15/2022] [Indexed: 02/07/2023] Open
Abstract
We report the case of a 22-year-old male who visited a cardiologist after the first episode of atrial fibrillation (AF). Echocardiography and magnetic resonance imaging revealed decreased left ventricular (LV) systolic function with dilated LV. An intermittent second-degree AV (atrioventricular) block was detected during 24 h Holter monitoring. Genetic test revealed the pathogenic variant of the BAG3 (BLC2-associated athanogene 3) gene. Due to the high risk of heart failure (HF) progression and ventricular arrhythmias, an event recorder was implanted and a pathogenetic HF treatment was prescribed. The analysis of genealogy revealed that the patient’s father, at the age of 32, was diagnosed with dilated cardiomyopathy (DCM) and recurrent AF episodes. Genetic testing also confirmed a pathogenic variant of the BAG3 gene. Currently, with the optimal treatment of HF, the patient’s disease has been stable for three years and the condition is closely monitored on an outpatient basis. So, we demonstrate the importance of early detection for genetic testing and the unusual stability exhibited by the patient‘s optimal medical therapy for 3 years.
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15
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Martin TG, Delligatti CE, Muntu NA, Stachowski-Doll MJ, Kirk JA. Pharmacological inhibition of BAG3-HSP70 with the proposed cancer therapeutic JG-98 is toxic for cardiomyocytes. J Cell Biochem 2022; 123:128-141. [PMID: 34487557 PMCID: PMC10037808 DOI: 10.1002/jcb.30140] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 07/11/2021] [Accepted: 08/26/2021] [Indexed: 11/06/2022]
Abstract
The co-chaperone Bcl2-associated athanogene-3 (BAG3) maintains cellular protein quality control through the regulation of heat shock protein 70 (HSP70). Cancer cells manipulate BAG3-HSP70-regulated pathways for tumor initiation and proliferation, which has led to the development of promising small molecule therapies, such as JG-98, which inhibit the BAG3-HSP70 interaction and mitigate tumor growth. However, it is not known how these broad therapies impact cardiomyocytes, where the BAG3-HSP70 complex is a key regulator of protein turnover and contractility. Here, we show that JG-98 exposure is toxic in neonatal rat ventricular myocytes (NRVMs). Using immunofluorescence microscopy to assess cell death, we found that apoptosis increased in NRVMs treated with JG-98 doses as low as 10 nM. JG-98 treatment also reduced autophagy flux and altered expression of BAG3 and several binding partners involved in BAG3-dependent autophagy, including SYNPO2 and HSPB8. We next assessed protein half-life with disruption of the BAG3-HSP70 complex by treating with JG-98 in the presence of cycloheximide and found BAG3, HSPB5, and HSPB8 half-lives were reduced, indicating that complex formation with HSP70 is important for their stability. Next, we assessed sarcomere structure using super-resolution microscopy and found that disrupting the interaction with HSP70 leads to sarcomere structural disintegration. To determine whether the effects of JG-98 could be mitigated by pharmacological autophagy induction, we cotreated NRVMs with rapamycin, which partially reduced the extent of apoptosis and sarcomere disarray. Finally, we investigated whether the effects of JG-98 extended to skeletal myocytes using C2C12 myotubes and found again increased apoptosis and reduced autophagic flux. Together, our data suggest that nonspecific targeting of the BAG3-HSP70 complex to treat cancer may be detrimental for cardiac and skeletal myocytes.
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Affiliation(s)
| | | | | | | | - Jonathan A. Kirk
- Corresponding Author: Jonathan A. Kirk, Ph.D., Department of Cell and Molecular Physiology, Loyola University Chicago Stritch School of Medicine, Center for Translational Research, Room 522, 2160 S. First Ave., Maywood, IL 60153, Ph: 708-216-6348,
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16
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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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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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