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Cizauskas HE, Burnham HV, Panni A, Peña A, Alvarez-Arce A, Davis MT, Araujo KN, Delligatti CE, Edassery S, Kirk JA, Arora R, Barefield DY. Proteolytic degradation of atrial sarcomere proteins underlies contractile defects in atrial fibrillation. Am J Physiol Heart Circ Physiol 2024; 327:H460-H472. [PMID: 38940916 DOI: 10.1152/ajpheart.00148.2024] [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: 03/08/2024] [Revised: 05/24/2024] [Accepted: 06/07/2024] [Indexed: 06/29/2024]
Abstract
Atrial fibrillation (AFib) is the most common cardiac rhythm disturbance, often treated via electrical cardioversion. Following rhythm restoration, a period of depressed mechanical function known as atrial stunning occurs, suggesting that defects in contractility occur in AFib and are revealed upon restoration of rhythm. This project aims to define the contractile remodeling that occurs in AFib. To assess contractile function, we used a canine atrial tachypacing model of induced AFib. Mass spectrometry analysis showed dysregulation of contractile proteins in samples from AFib compared with sinus rhythm atria. Atrial cardiomyocytes show reduced force of contraction, decreased resting tension, and increased calcium sensitivity in skinned single cardiomyocyte studies. These alterations correlated with degradation of myofilament proteins including myosin heavy chain altering force of contraction, titin altering resting tension, and troponin I altering calcium sensitivity. We measured degradation of other myofilament proteins, including cardiac myosin binding protein C and actinin, that show degradation products in the AFib samples that are absent in the sinus rhythm atria. Many of the degradation products appeared as discrete cleavage products that are generated by calpain proteolysis. We assessed calpain activity and found it to be significantly increased. These results provide an understanding of the contractile remodeling that occurs in AFib and provide insight into the molecular explanation for atrial stunning and the increased risk of atrial thrombus and stroke in AFib.NEW & NOTEWORTHY Atrial fibrillation is the most common cardiac rhythm disorder, and remodeling during atrial fibrillation is highly variable between patients. This study has defined the biophysical changes in contractility that occur in atrial fibrillation along with identifying potential molecular mechanisms that may drive this remodeling. This includes proteolysis of several myofilament proteins including titin, troponin I, myosin heavy chain, myosin binding protein C, and actinin, which is consistent with the observed contractile deficits.
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Affiliation(s)
- Hannah E Cizauskas
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Hope V Burnham
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Azaria Panni
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Alexandra Peña
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Alejandro Alvarez-Arce
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - M Therese Davis
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Kelly N Araujo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Christine E Delligatti
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Seby Edassery
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Jonathan A Kirk
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
| | - Rishi Arora
- Feinberg Cardiovascular and Renal Research Institute, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, Chicago, Illinois, United States
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Hashimoto K, Ohira M, Kodama A, Kimoto M, Inoue M, Toné S, Usui Y, Hanashima A, Goto T, Ogura Y, Ujihara Y, Mohri S. Loss of connectin novex-3 leads to heart dysfunction associated with impaired cardiomyocyte proliferation and abnormal nuclear mechanics. Sci Rep 2024; 14:13727. [PMID: 38877142 PMCID: PMC11178842 DOI: 10.1038/s41598-024-64608-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 06/11/2024] [Indexed: 06/16/2024] Open
Abstract
Connectin (also known as titin) is a giant striated muscle protein that functions as a molecular spring by providing elasticity to the sarcomere. Novex-3 is a short splice variant of connectin whose physiological function remains unknown. We have recently demonstrated using in vitro analyses that in addition to sarcomere expression, novex-3 was also expressed in cardiomyocyte nuclei exclusively during fetal life, where it provides elasticity/compliance to cardiomyocyte nuclei and promotes cardiomyocyte proliferation in the fetus, suggesting a non-sarcomeric function. Here, we analyzed novex-3 knockout mice to assess the involvement of this function in cardiac pathophysiology in vivo. Deficiency of novex-3 compromised fetal cardiomyocyte proliferation and induced the enlargement of individual cardiomyocytes in neonates. In adults, novex-3 deficiency resulted in chamber dilation and systolic dysfunction, associated with Ca2+ dysregulation, resulting in a reduced life span. Mechanistic analyses revealed a possible association between impaired proliferation and abnormal nuclear mechanics, including stiffer nuclei positioned peripherally with stabilized circumnuclear microtubules in knockout cardiomyocytes. Although the underlying causal relationships were not fully elucidated, these data show that novex-3 has a vital non-sarcomeric function in cardiac pathophysiology and serves as an early contributor to cardiomyocyte proliferation.
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Affiliation(s)
- Ken Hashimoto
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan.
| | - Momoko Ohira
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Aya Kodama
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Misaki Kimoto
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Mariko Inoue
- Central Research Institute, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Shigenobu Toné
- Laboratory of Molecular Developmental Biology, Graduate School of Science and Engineering, Tokyo Denki University, Hatoyama, Saitama, 350-0394, Japan
| | - Yuu Usui
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Akira Hanashima
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
| | - Takato Goto
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan
| | - Yuhei Ogura
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan
| | - Yoshihiro Ujihara
- Department of Electrical and Mechanical Engineering, Nagoya Institute of Technology, Nagoya, 466-8555, Japan
| | - Satoshi Mohri
- First Department of Physiology, Kawasaki Medical School, Kurashiki, 701-0192, Japan
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3
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Bailey LR, Bugg D, Reichardt IM, Ortaç CD, Nagle A, Gunaje J, Martinson A, Johnson R, MacCoss MJ, Sakamoto T, Kelly DP, Regnier M, Davis JM. MBNL1 Regulates Programmed Postnatal Switching Between Regenerative and Differentiated Cardiac States. Circulation 2024; 149:1812-1829. [PMID: 38426339 PMCID: PMC11147738 DOI: 10.1161/circulationaha.123.066860] [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: 08/22/2023] [Accepted: 02/05/2024] [Indexed: 03/02/2024]
Abstract
BACKGROUND Discovering determinants of cardiomyocyte maturity is critical for deeply understanding the maintenance of differentiated states and potentially reawakening endogenous regenerative programs in adult mammalian hearts as a therapeutic strategy. Forced dedifferentiation paired with oncogene expression is sufficient to drive cardiac regeneration, but elucidation of endogenous developmental regulators of the switch between regenerative and mature cardiomyocyte cell states is necessary for optimal design of regenerative approaches for heart disease. MBNL1 (muscleblind-like 1) regulates fibroblast, thymocyte, and erythroid differentiation and proliferation. Hence, we examined whether MBNL1 promotes and maintains mature cardiomyocyte states while antagonizing cardiomyocyte proliferation. METHODS MBNL1 gain- and loss-of-function mouse models were studied at several developmental time points and in surgical models of heart regeneration. Multi-omics approaches were combined with biochemical, histological, and in vitro assays to determine the mechanisms through which MBNL1 exerts its effects. RESULTS MBNL1 is coexpressed with a maturation-association genetic program in the heart and is regulated by the MEIS1/calcineurin signaling axis. Targeted MBNL1 overexpression early in development prematurely transitioned cardiomyocytes to hypertrophic growth, hypoplasia, and dysfunction, whereas loss of MBNL1 function increased cardiomyocyte cell cycle entry and proliferation through altered cell cycle inhibitor transcript stability. Moreover, MBNL1-dependent stabilization of estrogen-related receptor signaling was essential for maintaining cardiomyocyte maturity in adult myocytes. In accordance with these data, modulating MBNL1 dose tuned the temporal window of neonatal cardiac regeneration, where increased MBNL1 expression arrested myocyte proliferation and regeneration and MBNL1 deletion promoted regenerative states with prolonged myocyte proliferation. However, MBNL1 deficiency was insufficient to promote regeneration in the adult heart because of cell cycle checkpoint activation. CONCLUSIONS Here, MBNL1 was identified as an essential regulator of cardiomyocyte differentiated states, their developmental switch from hyperplastic to hypertrophic growth, and their regenerative potential through controlling an entire maturation program by stabilizing adult myocyte mRNAs during postnatal development and throughout adulthood. Targeting loss of cardiomyocyte maturity and downregulation of cell cycle inhibitors through MBNL1 deletion was not sufficient to promote adult regeneration.
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Affiliation(s)
- Logan R.J. Bailey
- Lab Medicine and Pathology, University of Washington, Seattle, WA
- Molecular and Cellular Biology, University of Washington, Seattle, WA
- Medical Scientist Training Program, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Darrian Bugg
- Lab Medicine and Pathology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Isabella M. Reichardt
- Bioengineering, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - C. Dessirée Ortaç
- Lab Medicine and Pathology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Abigail Nagle
- Bioengineering, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Jagadambika Gunaje
- Lab Medicine and Pathology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Amy Martinson
- Lab Medicine and Pathology, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | | | | | - Tomoya Sakamoto
- Cardiovascular Institute, Medicine, University of Pennsylvania, Philadelphia, PA
| | - Daniel P. Kelly
- Cardiovascular Institute, Medicine, University of Pennsylvania, Philadelphia, PA
| | - Michael Regnier
- Bioengineering, University of Washington, Seattle, WA
- Center for Translational Muscle Research, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
| | - Jennifer M. Davis
- Lab Medicine and Pathology, University of Washington, Seattle, WA
- Bioengineering, University of Washington, Seattle, WA
- Center for Translational Muscle Research, University of Washington, Seattle, WA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA
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4
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Zhu P, Li J, Yan F, Islam S, Lin X, Xu X. Allelic heterogeneity of TTNtv dilated cardiomyopathy can be modeled in adult zebrafish. JCI Insight 2024; 9:e175501. [PMID: 38412038 PMCID: PMC11128207 DOI: 10.1172/jci.insight.175501] [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: 09/07/2023] [Accepted: 02/21/2024] [Indexed: 02/29/2024] Open
Abstract
Allelic heterogeneity (AH) has been noted in truncational TTN-associated (TTNtv-associated) dilated cardiomyopathy (DCM); i.e., mutations affecting A-band-encoding exons are pathogenic, but those affecting Z-disc-encoding exons are likely benign. The lack of an in vivo animal model that recapitulates AH hinders the deciphering of the underlying mechanism. Here, we explored zebrafish as a candidate vertebrate model by phenotyping a collection of zebrafish ttntv alleles. We noted that cardiac function and sarcomere structure were more severely disrupted in ttntv-A than in ttntv-Z homozygous embryos. Consistently, cardiomyopathy-like phenotypes were present in ttntv-A but not ttntv-Z adult heterozygous mutants. The phenotypes observed in ttntv-A alleles were recapitulated in null mutants with the full titin-encoding sequences removed. Defective autophagic flux, largely due to impaired autophagosome-lysosome fusion, was also noted only in ttntv-A but not in ttntv-Z models. Moreover, we found that genetic manipulation of ulk1a restored autophagy flux and rescued cardiac dysfunction in ttntv-A animals. Together, our findings presented adult zebrafish as an in vivo animal model for studying AH in TTNtv DCM, demonstrated TTN loss of function is sufficient to trigger ttntv DCM in zebrafish, and uncovered ulk1a as a potential therapeutic target gene for TTNtv DCM.
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Affiliation(s)
- Ping Zhu
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Jiarong Li
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
- Department of Cardiovascular Surgery, Second Xiangya Hospital, Central South University, Changsha, China
| | - Feixiang Yan
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Shahidul Islam
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Xueying Lin
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | - Xiaolei Xu
- Department of Biochemistry and Molecular Biology and
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA
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5
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Garg A, Jansen S, Zhang R, Lavine KJ, Greenberg MJ. Dilated cardiomyopathy-associated skeletal muscle actin (ACTA1) mutation R256H disrupts actin structure and function and causes cardiomyocyte hypocontractility. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.10.583979. [PMID: 38559046 PMCID: PMC10979883 DOI: 10.1101/2024.03.10.583979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Skeletal muscle actin (ACTA1) mutations are a prevalent cause of skeletal myopathies consistent with ACTA1's high expression in skeletal muscle. Rare de novo mutations in ACTA1 associated with combined cardiac and skeletal myopathies have been reported, but ACTA1 represents only ~20% of the total actin pool in cardiomyocytes, making its role in cardiomyopathy controversial. Here we demonstrate how a mutation in an actin isoform expressed at low levels in cardiomyocytes can cause cardiomyopathy by focusing on a unique ACTA1 mutation, R256H. We previously identified this mutation in multiple family members with dilated cardiomyopathy (DCM), who had reduced systolic function without clinical skeletal myopathy. Using a battery of multiscale biophysical tools, we show that R256H has potent functional effects on ACTA1 function at the molecular scale and in human cardiomyocytes. Importantly, we demonstrate that R256H acts in a dominant manner, where the incorporation of small amounts of mutant protein into thin filaments is sufficient to disrupt molecular contractility, and that this effect is dependent on the presence of troponin and tropomyosin. To understand the structural basis of this change in regulation, we resolved a structure of R256H filaments using Cryo-EM, and we see alterations in actin's structure that have the potential to disrupt interactions with tropomyosin. Finally, we show that ACTA1R256H/+ human induced pluripotent stem cell cardiomyocytes demonstrate reduced contractility and sarcomeric disorganization. Taken together, we demonstrate that R256H has multiple effects on ACTA1 function that are sufficient to cause reduced contractility and establish a likely causative relationship between ACTA1 R256H and clinical cardiomyopathy.
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Affiliation(s)
- Ankit Garg
- Division of Cardiology, Department of Medicine Johns Hopkins University Baltimore MD USA
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Silvia Jansen
- Department of Cell Biology and Physiology, Washington University in St. Louis, St. Louis, MO, United States
| | - Rui Zhang
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Kory J. Lavine
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO
| | - Michael J. Greenberg
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri, USA
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6
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Hinson JT, Campbell SG. TTN truncation variants produce sarcomere-integrating proteins of uncertain functional significance. J Clin Invest 2024; 134:e175206. [PMID: 38226618 PMCID: PMC10786689 DOI: 10.1172/jci175206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024] Open
Abstract
Titin (TTN) is one of the largest and most complex proteins expressed in humans, and truncation variants are the most prevalent genetic lesion identified in individuals with dilated cardiomyopathy (DCM) or other disorders of impaired cardiac contractility. Two reports in this issue of the JCI shed light on a potential mechanism involving truncated TTN sarcomere integration and the potential for disruption of sarcomere structural integrity. Kellermayer, Tordai, and colleagues confirmed the presence of truncated TTN protein in human DCM samples. McAfee and authors developed a patient-specific TTN antibody to study truncated TTN subcellular localization and to explore its functional consequences. A "poison peptide" mechanism emerges that inspires alternative therapeutic approaches while opening new lines for inquiry, such as the role of haploinsufficiency of full-length TTN protein, mechanisms explaining sarcomere dysfunction, and explanations for variable penetrance.
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Affiliation(s)
- J. Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut, USA
- Cardiology Center, UConn Health, Farmington, Connecticut, USA
| | - Stuart G. Campbell
- Department of Biomedical Engineering, Yale University, New Haven, Connecticut, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, Connecticut, USA
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7
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Goldstein AJ, Padgett RM, Bremner SB, Higashi T, Obenaus AM, Bolduan S, Mack DL, Sniadecki NJ. Engineered Heart Tissues for Standard 96-Well Tissue Culture Plates. Methods Mol Biol 2024; 2805:89-100. [PMID: 39008175 DOI: 10.1007/978-1-0716-3854-5_5] [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] [Indexed: 07/16/2024]
Abstract
Engineered heart tissues (EHTs) have been shown to be a valuable platform for disease investigation and therapeutic testing by increasing human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) maturity and better recreating the native cardiac environment. The protocol detailed in this chapter describes the generation of miniaturized EHTs (mEHTs) incorporating hiPSC-CMs and human stromal cells in a fibrin hydrogel. This platform utilizes an array of silicone posts designed to fit in a standard 96-well tissue culture plate. Stromal cells and hiPSC-CMs are cast in a fibrin matrix suspended between two silicone posts, forming an mEHT that produces synchronous muscle contractions. The platform presented here has the potential to be used for high throughput characterization and screening of disease phenotypes and novel therapeutics through measurements of the myocardial function, including contractile force and calcium handling, and its compatibility with immunostaining.
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Affiliation(s)
- Alex J Goldstein
- Department of Lab Medicine and Pathology, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
| | - Ruby M Padgett
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Samantha B Bremner
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Ty Higashi
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Ava M Obenaus
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Sam Bolduan
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - David L Mack
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Department of Rehabilitation Medicine, University of Washington, Seattle, WA, USA
| | - Nathan J Sniadecki
- Department of Lab Medicine and Pathology, University of Washington, Seattle, WA, USA.
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA.
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.
- Department of Mechanical Engineering, University of Washington, Seattle, WA, USA.
- Department of Bioengineering, University of Washington, Seattle, WA, USA.
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8
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Liu Q, Xu C, Jin J, Li W, Liang J, Zhou S, Weng Z, Zhou Y, Liao X, Gu A. Early-life exposure to lead changes cardiac development and compromises long-term cardiac function. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 904:166667. [PMID: 37652374 DOI: 10.1016/j.scitotenv.2023.166667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 08/17/2023] [Accepted: 08/27/2023] [Indexed: 09/02/2023]
Abstract
Lead (Pb) is widely used in industrial and daily-use consumer products. Early-life exposure may increase the risk of lead-related heart problems in childhood. However, the effects of early-life lead exposure on fetal heart development and long-term cardiac outcomes are unknown. In this study, pregnant ICR mice were exposed to lead acetate trihydrate (50 mg/kg/d) via oral gavage from gestation day 1.5 until offspring weaning. Thereafter, the second hit model was established, two groups of offspring (4 weeks old) were either administered sterile saline or Angiotensin II (Ang II) for 4 weeks until euthanasia. We investigated lead-induced offspring heart damage from embryonic period to adulthood by echocardiographic analysis, pathological H&E staining, and ultrastructural examination, as well as mitochondrial function detection. The results showed early-life lead exposure predisposed offspring mice to decreased ejection fraction, increased left ventricular volume, accompanied by hypertrophy and dilation, cardiomyocyte sarcomere dysplasia, abnormal mitochondrial structure, mitochondrial dysfunction, and decreased expression of key sarcomeric and mitochondrial genes, rendering them more susceptible to cardiac hypertrophy, vascular wall thickening, cardiac fibrosis, apoptosis, and heart failure induced by Ang II infusion. This study elucidates early-life low dose lead exposure compromises cardiac development and exacerbates second hit-induced cardiac pathological responses in adulthood, which furnishes crucial scientific evidence pertaining to the cardiac toxicity and risk evaluation associated with early-life exposure to lead.
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Affiliation(s)
- Qian Liu
- State Key Laboratory of Reproductive Medicine and Offspring Health, School of Public Health, Nanjing Medical University, Nanjing, China; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Cheng Xu
- State Key Laboratory of Reproductive Medicine and Offspring Health, School of Public Health, Nanjing Medical University, Nanjing, China; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Jing Jin
- Department of Cardiovascular Surgery, The Second Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Wenxiang Li
- State Key Laboratory of Reproductive Medicine and Offspring Health, School of Public Health, Nanjing Medical University, Nanjing, China; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Jingjia Liang
- State Key Laboratory of Reproductive Medicine and Offspring Health, School of Public Health, Nanjing Medical University, Nanjing, China; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Shijie Zhou
- State Key Laboratory of Reproductive Medicine and Offspring Health, School of Public Health, Nanjing Medical University, Nanjing, China; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Zhenkun Weng
- State Key Laboratory of Reproductive Medicine and Offspring Health, School of Public Health, Nanjing Medical University, Nanjing, China; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Center for Global Health, Nanjing Medical University, Nanjing, China
| | - Yong Zhou
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, Shanghai Institutes for Biological Sciences, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China.
| | - Xudong Liao
- College of Life Sciences, Nankai University, Tianjin, China.
| | - Aihua Gu
- State Key Laboratory of Reproductive Medicine and Offspring Health, School of Public Health, Nanjing Medical University, Nanjing, China; Collaborative Innovation Center for Cardiovascular Disease Translational Medicine, Center for Global Health, Nanjing Medical University, Nanjing, China.
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9
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Cizauskas HE, Burnham HV, Panni A, Pena A, Alvarez-Arce A, Davis MT, Araujo KN, Delligatti C, Edassery S, Kirk JA, Arora R, Barefield DY. Proteolytic degradation of atrial sarcomere proteins underlies contractile defects in atrial fibrillation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.05.565691. [PMID: 37961455 PMCID: PMC10635151 DOI: 10.1101/2023.11.05.565691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Aims Atrial fibrillation (AFib) is the most common cardiac rhythm disturbance. Treatment of AFib involves restoration of the atrial electrical rhythm. Following rhythm restoration, a period of depressed mechanical function known as atrial stunning occurs that involves decreased blood flow velocity and reduced atrial contractility. This suggests that defects in contractility occur in AFib and are revealed upon restoration of rhythm. The aim of this project is to define the contractile remodeling that occurs in AFib. Methods and Results To assess contractile function, we used a canine atrial tachypacing model of induced AFib. Mass spectrometry analysis showed dysregulation of contractile proteins in samples from AFib compared to sinus rhythm atria. Atrial cardiomyocytes showed reduced force of contraction in skinned single cardiomyocyte calcium-force studies. There were no significant differences in myosin heavy chain isoform expression. Resting tension is decreased in the AFib samples correlating with reduced full-length titin in the sarcomere. We measured degradation of other myofilament proteins including cMyBP-C, actinin, and cTnI, showing significant degradation in the AFib samples compared to sinus rhythm atria. Many of the protein degradation products appeared as discrete cleavage products that are generated by calpain proteolysis. We assessed calpain activity and found it to be significantly increased. Skinned cardiomyocytes from AFib atria showed decreased troponin I phosphorylation, consistent with the increased calcium sensitivity that was found within these cardiomyocytes. Conclusions With these results it can be concluded that AFib causes alterations in contraction that can be explained by both molecular changes occurring in myofilament proteins and overall myofilament protein degradation. These results provide an understanding of the contractile remodeling that occurs in AFib and provides insight into the molecular explanation for atrial stunning and the increased risk of atrial thrombus and stroke in AFib.
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10
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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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11
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Asencio A, Malingen S, Kooiker KB, Powers JD, Davis J, Daniel T, Moussavi-Harami F. Machine learning meets Monte Carlo methods for models of muscle's molecular machinery to classify mutations. J Gen Physiol 2023; 155:e202213291. [PMID: 37000171 PMCID: PMC10067704 DOI: 10.1085/jgp.202213291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 02/14/2023] [Accepted: 03/14/2023] [Indexed: 04/01/2023] Open
Abstract
The timing and magnitude of force generation by a muscle depend on complex interactions in a compliant, contractile filament lattice. Perturbations in these interactions can result in cardiac muscle diseases. In this study, we address the fundamental challenge of connecting the temporal features of cardiac twitches to underlying rate constants and their perturbations associated with genetic cardiomyopathies. Current state-of-the-art metrics for characterizing the mechanical consequence of cardiac muscle disease do not utilize information embedded in the complete time course of twitch force. We pair dimension reduction techniques and machine learning methods to classify underlying perturbations that shape the timing of twitch force. To do this, we created a large twitch dataset using a spatially explicit Monte Carlo model of muscle contraction. Uniquely, we modified the rate constants of this model in line with mouse models of cardiac muscle disease and varied mutation penetrance. Ultimately, the results of this study show that machine learning models combined with biologically informed dimension reduction techniques can yield excellent classification accuracy of underlying muscle perturbations.
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Affiliation(s)
- Anthony Asencio
- Department of Biology, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Division of Cardiology, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
| | - Sage Malingen
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
| | - Kristina B. Kooiker
- Division of Cardiology, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
| | - Joseph D. Powers
- Department of Bioengineering, University of California, San Diego, San Diego, CA, USA
| | - Jennifer Davis
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
- Department of Laboratory Medicine Pathology, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
| | - Thomas Daniel
- Department of Biology, University of Washington, Seattle, WA, USA
- Department of Bioengineering, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
| | - Farid Moussavi-Harami
- Division of Cardiology, University of Washington, Seattle, WA, USA
- Center for Transnational Muscle Research, University of Washington, Seattle, WA, USA
- Department of Laboratory Medicine Pathology, University of Washington, Seattle, WA, USA
- Center for Cardiovascular Biology, University of Washington, Seattle, WA, USA
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12
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Linke WA. Stretching the story of titin and muscle function. J Biomech 2023; 152:111553. [PMID: 36989971 DOI: 10.1016/j.jbiomech.2023.111553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Accepted: 03/14/2023] [Indexed: 03/29/2023]
Abstract
The discovery of the giant protein titin, also known as connectin, dates almost half a century back. In this review, I recapitulate major advances in the discovery of the titin filaments and the recognition of their properties and function until today. I briefly discuss how our understanding of the layout and interactions of titin in muscle sarcomeres has evolved and review key facts about the titin sequence at the gene (TTN) and protein levels. I also touch upon properties of titin important for the stability of the contractile units and the assembly and maintenance of sarcomeric proteins. The greater part of my discussion centers around the mechanical function of titin in skeletal muscle. I cover milestones of research on titin's role in stretch-dependent passive tension development, recollect the reasons behind the enormous elastic diversity of titin, and provide an update on the molecular mechanisms of titin elasticity, details of which are emerging even now. I reflect on current knowledge of how muscle fibers behave mechanically if titin stiffness is removed and how titin stiffness can be dynamically regulated, such as by posttranslational modifications or calcium binding. Finally, I highlight novel and exciting, but still controversially discussed, insight into the role titin plays in active tension development, such as length-dependent activation and contraction from longer muscle lengths.
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Affiliation(s)
- Wolfgang A Linke
- Institute of Physiology II, University of Münster, Germany; Clinic for Cardiology and Pneumology, University Medical Center Göttingen, Germany; German Centre for Cardiovascular Research, Berlin, Germany.
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13
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Xu Y, Ma Q, Ren J, Chen L, Guo W, Feng K, Zeng Z, Huang T, Cai Y. Using Machine Learning Methods in Identifying Genes Associated with COVID-19 in Cardiomyocytes and Cardiac Vascular Endothelial Cells. Life (Basel) 2023; 13:life13041011. [PMID: 37109540 PMCID: PMC10146712 DOI: 10.3390/life13041011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 04/02/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Corona Virus Disease 2019 (COVID-19) not only causes respiratory system damage, but also imposes strain on the cardiovascular system. Vascular endothelial cells and cardiomyocytes play an important role in cardiac function. The aberrant expression of genes in vascular endothelial cells and cardiomyocytes can lead to cardiovascular diseases. In this study, we sought to explain the influence of respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on the gene expression levels of vascular endothelial cells and cardiomyocytes. We designed an advanced machine learning-based workflow to analyze the gene expression profile data of vascular endothelial cells and cardiomyocytes from patients with COVID-19 and healthy controls. An incremental feature selection method with a decision tree was used in building efficient classifiers and summarizing quantitative classification genes and rules. Some key genes, such as MALAT1, MT-CO1, and CD36, were extracted, which exert important effects on cardiac function, from the gene expression matrix of 104,182 cardiomyocytes, including 12,007 cells from patients with COVID-19 and 92,175 cells from healthy controls, and 22,438 vascular endothelial cells, including 10,812 cells from patients with COVID-19 and 11,626 cells from healthy controls. The findings reported in this study may provide insights into the effect of COVID-19 on cardiac cells and further explain the pathogenesis of COVID-19, and they may facilitate the identification of potential therapeutic targets.
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Affiliation(s)
- Yaochen Xu
- Department of Mathematics, School of Sciences, Shanghai University, Shanghai 200444, China
| | - Qinglan Ma
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Jingxin Ren
- School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Lei Chen
- College of Information Engineering, Shanghai Maritime University, Shanghai 201306, China
| | - Wei Guo
- Key Laboratory of Stem Cell Biology, Shanghai Jiao Tong University School of Medicine (SJTUSM) & Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai 200030, China
| | - Kaiyan Feng
- Department of Computer Science, Guangdong AIB Polytechnic College, Guangzhou 510507, China
| | - Zhenbing Zeng
- Department of Mathematics, School of Sciences, Shanghai University, Shanghai 200444, China
| | - Tao Huang
- Bio-Med Big Data Center, CAS Key Laboratory of Computational Biology, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- CAS Key Laboratory of Tissue Microenvironment and Tumor, Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yudong Cai
- Department of Mathematics, School of Sciences, Shanghai University, Shanghai 200444, China
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14
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Li ZH, Wang J, Xu JP, Wang J, Yang X. Recent advances in CRISPR-based genome editing technology and its applications in cardiovascular research. Mil Med Res 2023; 10:12. [PMID: 36895064 PMCID: PMC9999643 DOI: 10.1186/s40779-023-00447-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 02/14/2023] [Indexed: 03/11/2023] Open
Abstract
The rapid development of genome editing technology has brought major breakthroughs in the fields of life science and medicine. In recent years, the clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editing toolbox has been greatly expanded, not only with emerging CRISPR-associated protein (Cas) nucleases, but also novel applications through combination with diverse effectors. Recently, transposon-associated programmable RNA-guided genome editing systems have been uncovered, adding myriads of potential new tools to the genome editing toolbox. CRISPR-based genome editing technology has also revolutionized cardiovascular research. Here we first summarize the advances involving newly identified Cas orthologs, engineered variants and novel genome editing systems, and then discuss the applications of the CRISPR-Cas systems in precise genome editing, such as base editing and prime editing. We also highlight recent progress in cardiovascular research using CRISPR-based genome editing technologies, including the generation of genetically modified in vitro and animal models of cardiovascular diseases (CVD) as well as the applications in treating different types of CVD. Finally, the current limitations and future prospects of genome editing technologies are discussed.
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Affiliation(s)
- Zhen-Hua Li
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, 100071, China
| | - Jun Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, 100071, China
| | - Jing-Ping Xu
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, 100071, China.,Yaneng BIOScience (Shenzhen) Co., Ltd., Shenzhen, 518102, Guangdong, China
| | - Jian Wang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, 100071, China.
| | - Xiao Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, 100071, China.
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15
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Abstract
Heart disease is a significant burden on global health care systems and is a leading cause of death each year. To improve our understanding of heart disease, high quality disease models are needed. These will facilitate the discovery and development of new treatments for heart disease. Traditionally, researchers have relied on 2D monolayer systems or animal models of heart disease to elucidate pathophysiology and drug responses. Heart-on-a-chip (HOC) technology is an emerging field where cardiomyocytes among other cell types in the heart can be used to generate functional, beating cardiac microtissues that recapitulate many features of the human heart. HOC models are showing great promise as disease modeling platforms and are poised to serve as important tools in the drug development pipeline. By leveraging advances in human pluripotent stem cell-derived cardiomyocyte biology and microfabrication technology, diseased HOCs are highly tuneable and can be generated via different approaches such as: using cells with defined genetic backgrounds (patient-derived cells), adding small molecules, modifying the cells' environment, altering cell ratio/composition of microtissues, among others. HOCs have been used to faithfully model aspects of arrhythmia, fibrosis, infection, cardiomyopathies, and ischemia, to name a few. In this review, we highlight recent advances in disease modeling using HOC systems, describing instances where these models outperformed other models in terms of reproducing disease phenotypes and/or led to drug development.
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Affiliation(s)
- Omar Mourad
- Toronto General Hospital Research Institute (O.M., R.Y., M.L., S.S.N.), University Health Network, Toronto, Canada.,Institute of Biomedical Engineering (O.M., R.Y., M.L., S.S.N.), University of Toronto, Canada
| | - Ryan Yee
- Toronto General Hospital Research Institute (O.M., R.Y., M.L., S.S.N.), University Health Network, Toronto, Canada.,Institute of Biomedical Engineering (O.M., R.Y., M.L., S.S.N.), University of Toronto, Canada
| | - Mengyuan Li
- Toronto General Hospital Research Institute (O.M., R.Y., M.L., S.S.N.), University Health Network, Toronto, Canada.,Institute of Biomedical Engineering (O.M., R.Y., M.L., S.S.N.), University of Toronto, Canada
| | - Sara S Nunes
- Toronto General Hospital Research Institute (O.M., R.Y., M.L., S.S.N.), University Health Network, Toronto, Canada.,Ajmera Transplant Center (S.S.N.), University Health Network, Toronto, Canada.,Institute of Biomedical Engineering (O.M., R.Y., M.L., S.S.N.), University of Toronto, Canada.,Department of Laboratory Medicine and Pathobiology (S.S.N.), University of Toronto, Canada.,Heart and Stroke/Richard Lewar Centre of Excellence (S.S.N.), University of Toronto, Canada
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16
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Qi Y, Ji X, Ding H, Wang Y, Liu X, Zhang Y, Yin A. A spectrum of clinical severity of recessive titinopathies in prenatal. Front Genet 2023; 13:1064474. [PMID: 36761691 PMCID: PMC9907677 DOI: 10.3389/fgene.2022.1064474] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Accepted: 12/23/2022] [Indexed: 01/26/2023] Open
Abstract
Variants in TTN are associated with a broad range of clinical phenotypes, from dominant adult-onset dilated cardiomyopathy to recessive infantile-onset myopathy. However, few foetal cases have been reported for multiple reasons. Next-generation sequencing has facilitated the prenatal identification of a growing number of suspected titinopathy variants. We investigated six affected foetuses from three families, completed the intrauterine course of the serial phenotypic spectrum of TTN, and discussed the genotype-phenotype correlations from a broader perspective. The recognizable prenatal feature onset at the second trimester was started with reduced movement, then contracture 3-6 weeks later, followed with/without hydrops, finally at late pregnancy was accompanied with polyhydramnio (major) or oligohydramnios. Two cases with typical arthrogryposis-hydrops sequences identified a meta-only transcript variant c.36203-1G>T. Deleterious transcriptional consequences of the substitution were verified by minigene splicing analysis. Case 3 identified a homozygous splicing variant in the constitutively expressed Z-disc. It presented a milder phenotype than expected, which was presumably saved by the isoform of corons. A summary of the foetal-onset titinopathy cases implied that variants in TTN present with a series of signs and a spectrum of clinical severity, which followed the dosage/positional effect; the meta-only transcript allele involvement may be a prerequisite for the development of fatal hydrops.
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Affiliation(s)
- Yiming Qi
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Xueqi Ji
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Guangzhou Medical University, Guangzhou, China
| | - Hongke Ding
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Yunan Wang
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | | | - Yan Zhang
- Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China
| | - Aihua Yin
- Prenatal Diagnosis Centre, Guangdong Women and Children Hospital, Guangzhou, China,Maternal and Children Metabolic-Genetic Key Laboratory, Guangdong Women and Children Hospital, Guangzhou, China,*Correspondence: Aihua Yin,
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17
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Marcello M, Cetrangolo V, Savarese M, Udd B. Use of animal models to understand titin physiology and pathology. J Cell Mol Med 2022; 26:5103-5112. [PMID: 36065969 PMCID: PMC9575118 DOI: 10.1111/jcmm.17533] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/24/2022] [Accepted: 08/26/2022] [Indexed: 12/01/2022] Open
Abstract
In recent years, increasing attention has been paid to titin (TTN) and its mutations. Heterozygous TTN truncating variants (TTNtv) increase the risk of a cardiomyopathy. At the same time, TTNtv and few missense variants have been identified in patients with mainly recessive skeletal muscle diseases. The pathogenic mechanisms underlying titin‐related diseases are still partly unknown. Similarly, the titin mechanical and functional role in the muscle contraction are far from being exhaustively clarified. In the last few years, several animal models carrying variants in the titin gene have been developed and characterized to study the structural and mechanical properties of specific titin domains or to mimic patients' mutations. This review describes the main animal models so far characterized, including eight mice models and three fish models (Medaka and Zebrafish) and discusses the useful insights provided by a thorough characterization of the cell‐, tissue‐ and organism‐phenotypes in these models.
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Affiliation(s)
| | | | - Marco Savarese
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland
| | - Bjarne Udd
- Folkhälsan Research Center, Helsinki, Finland.,Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki, Finland.,Department of Neurology, Vaasa Central Hospital, Vaasa, Finland
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18
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Molecular genetic mechanisms of dilated cardiomyopathy. Curr Opin Genet Dev 2022; 76:101959. [PMID: 35870234 DOI: 10.1016/j.gde.2022.101959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/21/2022] [Accepted: 06/23/2022] [Indexed: 11/20/2022]
Abstract
Heart failure (HF) is a rapidly growing cardiovascular condition with a prevalence of ~40 million individuals worldwide [1]. While HF can be caused by acquired conditions such as myocardial infarctions and viruses [2], the genetic basis for HF is rapidly emerging particularly for dilated cardiomyopathy (DCM) that is the most prevalent HF type. In this review, insights from the rapid expansion in next-generation sequencing technologies applied in the HF clinic are merged with recent functional genomics studies to provide a contemporary view of DCM molecular genetics.
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19
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Kötter S, Krüger M. Protein Quality Control at the Sarcomere: Titin Protection and Turnover and Implications for Disease Development. Front Physiol 2022; 13:914296. [PMID: 35846001 PMCID: PMC9281568 DOI: 10.3389/fphys.2022.914296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/10/2022] [Indexed: 11/26/2022] Open
Abstract
Sarcomeres are mainly composed of filament and signaling proteins and are the smallest molecular units of muscle contraction and relaxation. The sarcomere protein titin serves as a molecular spring whose stiffness mediates myofilament extensibility in skeletal and cardiac muscle. Due to the enormous size of titin and its tight integration into the sarcomere, the incorporation and degradation of the titin filament is a highly complex task. The details of the molecular processes involved in titin turnover are not fully understood, but the involvement of different intracellular degradation mechanisms has recently been described. This review summarizes the current state of research with particular emphasis on the relationship between titin and protein quality control. We highlight the involvement of the proteasome, autophagy, heat shock proteins, and proteases in the protection and degradation of titin in heart and skeletal muscle. Because the fine-tuned balance of degradation and protein expression can be disrupted under pathological conditions, the review also provides an overview of previously known perturbations in protein quality control and discusses how these affect sarcomeric proteins, and titin in particular, in various disease states.
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20
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Abstract
PURPOSE OF REVIEW Truncating TTN variants (TTNtv) are the most common genetic cause of dilated cardiomyopathy (DCM), but the underlying mechanisms are incompletely understood and effective therapeutic strategies are lacking. Here we review recent data that shed new light on the functional consequences of TTNtv and how these effects may vary with mutation location. RECENT FINDINGS Whether TTNtv act by haploinsufficiency or dominant negative effects has been hotly debated. New evidence now implicates both mechanisms in TTNtv-related DCM, showing reduced titin content and persistent truncated titin that may be incorporated into protein aggregates. The extent to which aggregate formation and protein quality control defects differ with TTNtv location and contribute to contractile dysfunction is unresolved. TTNtv-associated DCM has a complex etiology that involves varying combinations of wild-type titin deficiency and dominant negative effects of truncated mutant titin. Therapeutic strategies to improve protein handling may be beneficial in some cases.
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21
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Bremner S, Goldstein AJ, Higashi T, Sniadecki NJ. Engineered Heart Tissues for Contractile, Structural, and Transcriptional Assessment of Human Pluripotent Stem Cell-Derived Cardiomyocytes in a Three-Dimensional, Auxotonic Environment. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2022; 2485:87-97. [PMID: 35618900 DOI: 10.1007/978-1-0716-2261-2_6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Three-dimensional, human engineered heart tissue promotes maturation of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and provides a useful platform for in vitro cardiac development and disease modeling. This protocol describes the generation of fibrin-based engineered heart tissues (EHTs) containing hiPSC-CMs and human stromal cells. The platform makes use of racks of silicone posts that fit a standard 24-well dish. Stromal cells and hiPSC-CMs are cast in a fibrin hydrogel suspended between two silicone posts, forming an engineered tissue that generates synchronous contractions. The platform described herein is amenable to various measures of cardiac function including measurement of contractile force and calcium handling, as well as molecular biology assays and immunostaining.
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Affiliation(s)
- Samantha Bremner
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.,Department of Bioengineering, University of Washington, Seattle, WA, USA
| | - Alex J Goldstein
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.,Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.,Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA, USA
| | - Ty Higashi
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA.,Department of Mechanical Engineering, University of Washington, Seattle, WA, USA
| | - Nathan J Sniadecki
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, USA. .,Department of Bioengineering, University of Washington, Seattle, WA, USA. .,Department of Mechanical Engineering, University of Washington, Seattle, WA, USA. .,Department of Laboratory Medicine & Pathology, University of Washington, Seattle, WA, USA.
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22
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El Kadiri Y, Ratbi I, Sefiani A, Lyahyai J. Clinical and molecular genetic analysis of early-onset myopathy with fatal cardiomyopathy: Novel biallelic M-line TTN mutation and review of the literature. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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23
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Romano R, Ghahremani S, Zimmerman T, Legere N, Thakar K, Ladha FA, Pettinato AM, Hinson JT. Reading Frame Repair of TTN Truncation Variants Restores Titin Quantity and Functions. Circulation 2022; 145:194-205. [PMID: 34905694 PMCID: PMC8766920 DOI: 10.1161/circulationaha.120.049997] [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: 07/12/2020] [Accepted: 11/18/2021] [Indexed: 01/21/2023]
Abstract
BACKGROUND Titin truncation variants (TTNtvs) are the most common inheritable risk factor for dilated cardiomyopathy (DCM), a disease with high morbidity and mortality. The pathogenicity of TTNtvs has been associated with structural localization as A-band variants overlapping myosin heavy chain-binding domains are more pathogenic than I-band variants by incompletely understood mechanisms. Demonstrating why A-band variants are highly pathogenic for DCM could reveal new insights into DCM pathogenesis, titin (TTN) functions, and therapeutic targets. METHODS We constructed human cardiomyocyte models harboring DCM-associated TTNtvs within A-band and I-band structural domains using induced pluripotent stem cell and CRISPR technologies. We characterized normal TTN isoforms and variant-specific truncation peptides by their expression levels and cardiomyocyte localization using TTN protein gel electrophoresis and immunofluorescence, respectively. Using CRISPR to ablate A-band variant-specific truncation peptides through introduction of a proximal I-band TTNtv, we studied genetic mechanisms in single cardiomyocyte and 3-dimensional, biomimetic cardiac microtissue functional assays. Last, we engineered a full-length TTN protein reporter assay and used next-generation sequencing assays to develop a CRISPR therapeutic for somatic cell genome editing TTNtvs. RESULTS An A-band TTNtv dose-dependently impaired cardiac microtissue twitch force, reduced full-length TTN levels, and produced abundant TTN truncation peptides. TTN truncation peptides integrated into nascent myofibril-like structures and impaired myofibrillogenesis. CRISPR ablation of TTN truncation peptides using a proximal I-band TTNtv partially restored cardiac microtissue twitch force deficits. Cardiomyocyte genome editing using SpCas9 and a TTNtv-specific guide RNA restored the TTN protein reading frame, which increased full-length TTN protein levels, reduced TTN truncation peptides, and increased sarcomere function in cardiac microtissue assays. CONCLUSIONS An A-band TTNtv diminished sarcomere function greater than an I-band TTNtv in proportion to estimated DCM pathogenicity. Although both TTNtvs resulted in full-length TTN haploinsufficiency, only the A-band TTNtv produced TTN truncation peptides that impaired myofibrillogenesis and sarcomere function. CRISPR-mediated reading frame repair of the A-band TTNtv restored functional deficits, and could be adapted as a one-and-done genome editing strategy to target ≈30% of DCM-associated TTNtvs.
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Affiliation(s)
- Robert Romano
- University of Connecticut Health Center, Farmington, CT 06030, USA
| | | | - Talia Zimmerman
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Nicholas Legere
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Ketan Thakar
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Feria A. Ladha
- University of Connecticut Health Center, Farmington, CT 06030, USA
| | | | - J. Travis Hinson
- University of Connecticut Health Center, Farmington, CT 06030, USA
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
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24
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Powers JD, Kirkland NJ, Liu C, Razu SS, Fang X, Engler AJ, Chen J, McCulloch AD. Subcellular Remodeling in Filamin C Deficient Mouse Hearts Impairs Myocyte Tension Development during Progression of Dilated Cardiomyopathy. Int J Mol Sci 2022; 23:871. [PMID: 35055055 PMCID: PMC8779483 DOI: 10.3390/ijms23020871] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 12/28/2021] [Accepted: 01/11/2022] [Indexed: 01/15/2023] Open
Abstract
Dilated cardiomyopathy (DCM) is a life-threatening form of heart disease that is typically characterized by progressive thinning of the ventricular walls, chamber dilation, and systolic dysfunction. Multiple mutations in the gene encoding filamin C (FLNC), an actin-binding cytoskeletal protein in cardiomyocytes, have been found in patients with DCM. However, the mechanisms that lead to contractile impairment and DCM in patients with FLNC variants are poorly understood. To determine how FLNC regulates systolic force transmission and DCM remodeling, we used an inducible, cardiac-specific FLNC-knockout (icKO) model to produce a rapid onset of DCM in adult mice. Loss of FLNC reduced systolic force development in single cardiomyocytes and isolated papillary muscles but did not affect twitch kinetics or calcium transients. Electron and immunofluorescence microscopy showed significant defects in Z-disk alignment in icKO mice and altered myofilament lattice geometry. Moreover, a loss of FLNC induces a softening myocyte cortex and structural adaptations at the subcellular level that contribute to disrupted longitudinal force production during contraction. Spatially explicit computational models showed that these structural defects could be explained by a loss of inter-myofibril elastic coupling at the Z-disk. Our work identifies FLNC as a key regulator of the multiscale ultrastructure of cardiomyocytes and therefore plays an important role in maintaining systolic mechanotransmission pathways, the dysfunction of which may be key in driving progressive DCM.
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Affiliation(s)
- Joseph D. Powers
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Natalie J. Kirkland
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Canzhao Liu
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
| | - Swithin S. Razu
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Xi Fang
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
| | - Adam J. Engler
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
| | - Ju Chen
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
| | - Andrew D. McCulloch
- Department of Bioengineering, University of California San Diego, La Jolla, CA 92093, USA; (N.J.K.); (S.S.R.); (A.J.E.); (J.C.); (A.D.M.)
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA; (C.L.); (X.F.)
- Institute for Engineering in Medicine, University of California San Diego, La Jolla, CA 92093, USA
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25
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Gene Editing in Pluripotent Stem Cells and Their Derived Organoids. Stem Cells Int 2021; 2021:8130828. [PMID: 34887928 PMCID: PMC8651378 DOI: 10.1155/2021/8130828] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/22/2021] [Indexed: 12/26/2022] Open
Abstract
With the rapid rise in gene-editing technology, pluripotent stem cells (PSCs) and their derived organoids have increasingly broader and practical applications in regenerative medicine. Gene-editing technologies, from large-scale nucleic acid endonucleases to CRISPR, have ignited a global research and development boom with significant implications in regenerative medicine. The development of regenerative medicine technologies, regardless of whether it is PSCs or gene editing, is consistently met with controversy. Are the tools for rewriting the code of life a boon to humanity or a Pandora's box? These technologies raise concerns regarding ethical issues, unexpected mutations, viral infection, etc. These concerns remain even as new treatments emerge. However, the potential negatives cannot obscure the virtues of PSC gene editing, which have, and will continue to, benefit mankind at an unprecedented rate. Here, we briefly introduce current gene-editing technology and its application in PSCs and their derived organoids, while addressing ethical concerns and safety risks and discussing the latest progress in PSC gene editing. Gene editing in PSCs creates visualized in vitro models, providing opportunities for examining mechanisms of known and unknown mutations and offering new possibilities for the treatment of cancer, genetic diseases, and other serious or refractory disorders. From model construction to treatment exploration, the important role of PSCs combined with gene editing in basic and clinical medicine studies is illustrated. The applications, characteristics, and existing challenges are summarized in combination with our lab experiences in this field in an effort to help gene-editing technology better serve humans in a regulated manner. Current preclinical and clinical trials have demonstrated initial safety and efficacy of PSC gene editing; however, for better application in clinical settings, additional investigation is warranted.
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26
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Yamada T, Nomura S. Recent Findings Related to Cardiomyopathy and Genetics. Int J Mol Sci 2021; 22:12522. [PMID: 34830403 PMCID: PMC8623065 DOI: 10.3390/ijms222212522] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 11/16/2021] [Indexed: 12/13/2022] Open
Abstract
With the development and advancement of next-generation sequencing (NGS), genetic analysis is becoming more accessible. High-throughput genetic studies using NGS have contributed to unraveling the association between cardiomyopathy and genetic background, as is the case with many other diseases. Rare variants have been shown to play major roles in the pathogenesis of cardiomyopathy, which was empirically recognized as a monogenic disease, and it has been elucidated that the clinical course of cardiomyopathy varies depending on the causative genes. These findings were not limited to dilated and hypertrophic cardiomyopathy; similar trends were reported one after another for peripartum cardiomyopathy (PPCM), cancer therapy-related cardiac dysfunction (CTRCD), and alcoholic cardiomyopathy (ACM). In addition, as the association between clinical phenotypes and the causative genes becomes clearer, progress is being made in elucidating the mechanisms and developing novel therapeutic agents. Recently, it has been suggested that not only rare variants but also common variants contribute to the development of cardiomyopathy. Cardiomyopathy and genetics are approaching a new era, which is summarized here in this overview.
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Grants
- JP21ek0210152, JP21gm6210010, JP20bm0704026, JP21ek0210141, JP21ek0109440, JP21ek0109487, JP21gm0810013, JP21km0405209, JP21ek0210118, JP21ek0109406, JP21ek0109543, JP21ek0109569 Japan Agency for Medical Research and Development
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Affiliation(s)
| | - Seitaro Nomura
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-8654, Japan;
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27
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van der Pijl RJ, Domenighetti AA, Sheikh F, Ehler E, Ottenheijm CAC, Lange S. The titin N2B and N2A regions: biomechanical and metabolic signaling hubs in cross-striated muscles. Biophys Rev 2021; 13:653-677. [PMID: 34745373 PMCID: PMC8553726 DOI: 10.1007/s12551-021-00836-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/23/2021] [Indexed: 02/07/2023] Open
Abstract
Muscle specific signaling has been shown to originate from myofilaments and their associated cellular structures, including the sarcomeres, costameres or the cardiac intercalated disc. Two signaling hubs that play important biomechanical roles for cardiac and/or skeletal muscle physiology are the N2B and N2A regions in the giant protein titin. Prominent proteins associated with these regions in titin are chaperones Hsp90 and αB-crystallin, members of the four-and-a-half LIM (FHL) and muscle ankyrin repeat protein (Ankrd) families, as well as thin filament-associated proteins, such as myopalladin. This review highlights biological roles and properties of the titin N2B and N2A regions in health and disease. Special emphasis is placed on functions of Ankrd and FHL proteins as mechanosensors that modulate muscle-specific signaling and muscle growth. This region of the sarcomere also emerged as a hotspot for the modulation of passive muscle mechanics through altered titin phosphorylation and splicing, as well as tethering mechanisms that link titin to the thin filament system.
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Affiliation(s)
| | - Andrea A. Domenighetti
- Shirley Ryan AbilityLab, Chicago, IL USA
- Department of Physical Medicine and Rehabilitation, Northwestern University, Chicago, IL USA
| | - Farah Sheikh
- Division of Cardiology, School of Medicine, UC San Diego, La Jolla, CA USA
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King’s College London, London, UK
| | - Coen A. C. Ottenheijm
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ USA
- Department of Physiology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
| | - Stephan Lange
- Division of Cardiology, School of Medicine, UC San Diego, La Jolla, CA USA
- Department of Molecular and Clinical Medicine, University of Gothenburg, Gothenburg, Sweden
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28
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McAfee Q, Chen CY, Yang Y, Caporizzo MA, Morley M, Babu A, Jeong S, Brandimarto J, Bedi KC, Flam E, Cesare J, Cappola TP, Margulies K, Prosser B, Arany Z. Truncated titin proteins in dilated cardiomyopathy. Sci Transl Med 2021; 13:eabd7287. [PMID: 34731015 PMCID: PMC9236909 DOI: 10.1126/scitranslmed.abd7287] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Truncating variants in TTN (TTNtvs) are the most common known cause of nonischemic dilated cardiomyopathy (DCM), but how TTNtvs cause disease has remained controversial. Efforts to detect truncated titin proteins in affected human DCM hearts have failed, suggesting that disease is caused by haploinsufficiency, but reduced amounts of titin protein have not yet been demonstrated. Here, we leveraged a collection of 184 explanted posttransplant DCM hearts to show, using specialized electrophoretic gels, Western blotting, allelic phasing, and unbiased proteomics, that truncated titin proteins can quantitatively be detected in human DCM hearts. The sizes of truncated proteins corresponded to that predicted by their respective TTNtvs; the truncated proteins were encoded by the TTNtv-bearing allele; and no degradation fragments from protein encoded by either allele were detectable. In parallel, full-length titin was less abundant in TTNtv+ than in TTNtv− DCM hearts. Disease severity or need for transplantation did not correlate with TTNtv location. Transcriptomic profiling revealed few differences in splicing or allelic imbalance of the TTN transcript between TTNtv+ and TTNtv− DCM hearts. Studies with isolated human adult cardiomyocytes revealed no defects in contractility in cells from TTNtv+ compared to TTNtv− DCM hearts. Together, these data demonstrate the presence of truncated titin protein in human TTNtv+ DCM, show reduced amounts of full-length titin protein in TTNtv+ DCM hearts, and support combined dominant-negative and haploinsufficiency contributions to disease.
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Affiliation(s)
- Quentin McAfee
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Christina Yingxian Chen
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Yifan Yang
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Matthew A. Caporizzo
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Michael Morley
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Apoorva Babu
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Sunhye Jeong
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Jeffrey Brandimarto
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Kenneth C. Bedi
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Emily Flam
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Joseph Cesare
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Thomas P. Cappola
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Kenneth Margulies
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Benjamin Prosser
- Department of Physiology, Pennsylvania Muscle Institute, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
| | - Zolt Arany
- Cardiovascular Institute, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, PA 19104, USA
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29
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Fomin A, Gärtner A, Cyganek L, Tiburcy M, Tuleta I, Wellers L, Folsche L, Hobbach AJ, von Frieling-Salewsky M, Unger A, Hucke A, Koser F, Kassner A, Sielemann K, Streckfuß-Bömeke K, Hasenfuss G, Goedel A, Laugwitz KL, Moretti A, Gummert JF, Dos Remedios CG, Reinecke H, Knöll R, van Heesch S, Hubner N, Zimmermann WH, Milting H, Linke WA. Truncated titin proteins and titin haploinsufficiency are targets for functional recovery in human cardiomyopathy due to TTN mutations. Sci Transl Med 2021; 13:eabd3079. [PMID: 34731013 DOI: 10.1126/scitranslmed.abd3079] [Citation(s) in RCA: 56] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Andrey Fomin
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany
| | - Anna Gärtner
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Lukas Cyganek
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Stem Cell Unit, University Medical Center, 37075 Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center, 37075 Göttingen, Germany
| | - Malte Tiburcy
- German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center, 37075 Göttingen, Germany
| | - Izabela Tuleta
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, 48149 University Hospital Münster, Münster, Germany
| | - Luisa Wellers
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Lina Folsche
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Anastasia J Hobbach
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, 48149 University Hospital Münster, Münster, Germany
| | | | - Andreas Unger
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Anna Hucke
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Franziska Koser
- Institute of Physiology II, University of Münster, 48149 Münster, Germany
| | - Astrid Kassner
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Katharina Sielemann
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Katrin Streckfuß-Bömeke
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany
| | - Gerd Hasenfuss
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany
| | - Alexander Goedel
- First Medical Department, Cardiology, Technical University of Munich, 81675 Munich, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Munich, Germany.,Department of Cell and Molecular Biology, Karolinska Institute, S-17177 Stockholm, Sweden
| | - Karl-Ludwig Laugwitz
- First Medical Department, Cardiology, Technical University of Munich, 81675 Munich, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Munich, Germany.,Munich Heart Alliance, 80802 Munich, Germany
| | - Alessandra Moretti
- First Medical Department, Cardiology, Technical University of Munich, 81675 Munich, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Munich, Germany.,Munich Heart Alliance, 80802 Munich, Germany
| | - Jan F Gummert
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany.,Department of Cardio-Thoracic Surgery, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | | | - Holger Reinecke
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, 48149 University Hospital Münster, Münster, Germany
| | - Ralph Knöll
- Department of Medicine, Integrated Cardio Metabolic Centre (ICMC), Heart and Vascular Theme, Karolinska Institute, S-17177 Stockholm, Sweden.,Bioscience Cardiovascular, Research and Early Development, Cardiovascular, Renal and Metabolism (CVRM), BioPharmaceuticals R&D, AstraZeneca, 43183 Gothenburg, Sweden
| | - Sebastiaan van Heesch
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Berlin, Germany.,Princess Máxima Center for Pediatric Oncology, 3584 CT Utrecht, Netherlands
| | - Norbert Hubner
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, 13125 Berlin, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Berlin, Germany.,Charité-Universitätsmedizin, 10117 Berlin, Germany.,Berlin Institute of Health, 10178 Berlin, Germany
| | - Wolfram H Zimmermann
- German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center, 37075 Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells," University of Göttingen, 37073 Göttingen, Germany
| | - Hendrik Milting
- Erich and Hanna Klessmann Institute, Heart and Diabetes Centre NRW, University Hospital of the Ruhr-University Bochum, 32545 Bad Oeynhausen, Germany
| | - Wolfgang A Linke
- Clinic for Cardiology and Pneumology, University Medical Center, 37075 Göttingen, Germany.,German Centre for Cardiovascular Research, 10785 Berlin, partner site Göttingen, Germany.,Institute of Physiology II, University of Münster, 48149 Münster, Germany
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30
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Müller E, Salcan S, Bongardt S, Barbosa DM, Krüger M, Kötter S. E3-ligase knock down revealed differential titin degradation by autopagy and the ubiquitin proteasome system. Sci Rep 2021; 11:21134. [PMID: 34702928 PMCID: PMC8548520 DOI: 10.1038/s41598-021-00618-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 09/30/2021] [Indexed: 01/09/2023] Open
Abstract
The sarcomere protein titin is a major determinant of cardiomyocyte stiffness and ventricular distensibility. The constant mechanical stress on titin requires well-controlled protein quality control, the exact mechanisms of which have not yet been fully elucidated. Here, we analyzed E3-ligases potentially responsible for cardiac titin ubiquitination and specifically studied the involvement of the autophagosomal system in titin degradation. Pharmacological inhibition of autophagy and the proteasome in cultured primary rat cardiomyocytes significantly elevated titin ubiquitination and increased titin degradation. Using in-vitro pull down assays we identified binding of E3-ligases MuRF1-3, CHIP and Fbx32 to several titin domains. Immunofluorescence analysis showed sarcomeric localization of the E3-ligases. siRNA-mediated knock-down of the E3-ligases MuRF-1, -3 and a combination of CHIP/Fbx32 significantly reduced autophagy-related titin ubiquitination, whereas knock-down of MuRF-2 and -3 reduced proteasome-related titin ubiquitination. We demonstrated that the proteasomal and the autophagosomal-lysosomal system participate in degradation of the titin filament. We found that ubiquitination and degradation of titin are partially regulated by E3-ligases of the MuRF family. We further identified CHIP and Fbx32 as E3-ligases involved in titin ubiquitination.
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Affiliation(s)
- Erik Müller
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Senem Salcan
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Sabine Bongardt
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - David Monteiro Barbosa
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Martina Krüger
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany
| | - Sebastian Kötter
- Department of Cardiovascular Physiology, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University Düsseldorf, Universitätsstr. 1, 22.03 02, 40225, Düsseldorf, Germany.
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31
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Loescher CM, Hobbach AJ, Linke WA. Titin (TTN): from molecule to modifications, mechanics and medical significance. Cardiovasc Res 2021; 118:2903-2918. [PMID: 34662387 PMCID: PMC9648829 DOI: 10.1093/cvr/cvab328] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 10/13/2021] [Indexed: 12/19/2022] Open
Abstract
The giant sarcomere protein titin is a major determinant of cardiomyocyte stiffness and contributor to cardiac strain sensing. Titin-based forces are highly regulated in health and disease, which aids in the regulation of myocardial function, including cardiac filling and output. Due to the enormous size, complexity, and malleability of the titin molecule, titin properties are also vulnerable to dysregulation, as observed in various cardiac disorders. This review provides an overview of how cardiac titin properties can be changed at a molecular level, including the role isoform diversity and post-translational modifications (acetylation, oxidation, and phosphorylation) play in regulating myocardial stiffness and contractility. We then consider how this regulation becomes unbalanced in heart disease, with an emphasis on changes in titin stiffness and protein quality control. In this context, new insights into the key pathomechanisms of human cardiomyopathy due to a truncation in the titin gene (TTN) are discussed. Along the way, we touch on the potential for titin to be therapeutically targeted to treat acquired or inherited cardiac conditions, such as HFpEF or TTN-truncation cardiomyopathy.
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Affiliation(s)
- Christine M Loescher
- Institute of Physiology II, University Hospital Münster, Robert-Koch-Str. 27B, Münster, 48149 Germany
| | - Anastasia J Hobbach
- Department of Cardiology I, Coronary, Peripheral Vascular Disease and Heart Failure, University Hospital Münster, Münster, Germany
| | - Wolfgang A Linke
- Institute of Physiology II, University Hospital Münster, Robert-Koch-Str. 27B, Münster, 48149 Germany
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32
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Luttrell SM, Smith AST, Mack DL. Creating stem cell-derived neuromuscular junctions in vitro. Muscle Nerve 2021; 64:388-403. [PMID: 34328673 PMCID: PMC9292444 DOI: 10.1002/mus.27360] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 05/28/2021] [Accepted: 06/21/2021] [Indexed: 12/14/2022]
Abstract
Recent development of novel therapies has improved mobility and quality of life for people suffering from inheritable neuromuscular disorders. Despite this progress, the majority of neuromuscular disorders are still incurable, in part due to a lack of predictive models of neuromuscular junction (NMJ) breakdown. Improvement of predictive models of a human NMJ would be transformative in terms of expanding our understanding of the mechanisms that underpin development, maintenance, and disease, and as a testbed with which to evaluate novel therapeutics. Induced pluripotent stem cells (iPSCs) are emerging as a clinically relevant and non‐invasive cell source to create human NMJs to study synaptic development and maturation, as well as disease modeling and drug discovery. This review will highlight the recent advances and remaining challenges to generating an NMJ capable of eliciting contraction of stem cell‐derived skeletal muscle in vitro. We explore the advantages and shortcomings of traditional NMJ culturing platforms, as well as the pioneering technologies and novel, biomimetic culturing systems currently in use to guide development and maturation of the neuromuscular synapse and extracellular microenvironment. Then, we will explore how this NMJ‐in‐a‐dish can be used to study normal assembly and function of the efferent portion of the neuromuscular arc, and how neuromuscular disease‐causing mutations disrupt structure, signaling, and function.
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Affiliation(s)
- Shawn M Luttrell
- Department of Rehabilitation Medicine, University of Washington, Seattle, Washington, USA.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA
| | - Alec S T Smith
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA.,Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
| | - David L Mack
- Department of Rehabilitation Medicine, University of Washington, Seattle, Washington, USA.,Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA.,Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
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33
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Dwyer KD, Coulombe KL. Cardiac mechanostructure: Using mechanics and anisotropy as inspiration for developing epicardial therapies in treating myocardial infarction. Bioact Mater 2021; 6:2198-2220. [PMID: 33553810 PMCID: PMC7822956 DOI: 10.1016/j.bioactmat.2020.12.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 12/14/2022] Open
Abstract
The mechanical environment and anisotropic structure of the heart modulate cardiac function at the cellular, tissue and organ levels. During myocardial infarction (MI) and subsequent healing, however, this landscape changes significantly. In order to engineer cardiac biomaterials with the appropriate properties to enhance function after MI, the changes in the myocardium induced by MI must be clearly identified. In this review, we focus on the mechanical and structural properties of the healthy and infarcted myocardium in order to gain insight about the environment in which biomaterial-based cardiac therapies are expected to perform and the functional deficiencies caused by MI that the therapy must address. From this understanding, we discuss epicardial therapies for MI inspired by the mechanics and anisotropy of the heart focusing on passive devices, which feature a biomaterials approach, and active devices, which feature robotic and cellular components. Through this review, a detailed analysis is provided in order to inspire further development and translation of epicardial therapies for MI.
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Affiliation(s)
- Kiera D. Dwyer
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
| | - Kareen L.K. Coulombe
- Center for Biomedical Engineering, School of Engineering, Brown University, Providence, RI, USA
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Duan Q, Tang C, Ma Z, Chen C, Shang X, Yue J, Jiang H, Gao Y, Xu B. Genomic Heterogeneity and Clonal Evolution in Gastroesophageal Junction Cancer Revealed by Single Cell DNA Sequencing. Front Oncol 2021; 11:672020. [PMID: 34046362 PMCID: PMC8144650 DOI: 10.3389/fonc.2021.672020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Accepted: 04/16/2021] [Indexed: 12/25/2022] Open
Abstract
Gastroesophageal junction (GEJ) cancer is a tumor that occurs at the junction of stomach and esophagus anatomically. GEJ cancer frequently metastasizes to lymph nodes, however the heterogeneity and clonal evolution process are unclear. This study is the first of this kind to use single cell DNA sequencing to determine genomic variations and clonal evolution related to lymph node metastasis. Multiple Annealing and Looping Based Amplification Cycles (MALBAC) and bulk exome sequencing were performed to detect single cell copy number variations (CNVs) and single nucleotide variations (SNVs) respectively. Four GEJ cancer patients were enrolled with two (Pt.3, Pt.4) having metastatic lymph nodes. The most common mutation we found happened in the TTN gene, which was reported to be related with the tumor mutation burden in cancers. Significant intra-patient heterogeneity in SNVs and CNVs were found. We identified the SNV subclonal architecture in each tumor. To study the heterogeneity of CNVs, the single cells were sequenced. The number of subclones in the primary tumor was larger than that in lymph nodes, indicating the heterogeneity of primary site was higher. We observed two patterns of multi-station lymph node metastasis: one was skip metastasis and the other was to follow the lymphatic drainage. Taken together, our single cell genomic analysis has revealed the heterogeneity and clonal evolution in GEJ cancer.
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Affiliation(s)
- Qingke Duan
- Department of Biochemistry and Molecular Biology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.,Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin, China
| | - Chao Tang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Zhao Ma
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Chuangui Chen
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Xiaobin Shang
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Jie Yue
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Hongjing Jiang
- Department of Minimally Invasive Esophageal Surgery, Tianjin Medical University Cancer Institute and Hospital, Tianjin, China
| | - Yan Gao
- Department of Biochemistry and Molecular Biology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.,Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin, China
| | - Bo Xu
- Department of Biochemistry and Molecular Biology, Tianjin Medical University Cancer Institute and Hospital, National Clinical Research Center for Cancer, Key Laboratory of Cancer Prevention and Therapy, Tianjin, China.,Tianjin's Clinical Research Center for Cancer, Key Laboratory of Breast Cancer Prevention and Therapy, Tianjin Medical University, Ministry of Education, Tianjin, China.,Center for Intelligent Oncology, Chongqing University Cancer Hospital, Chongqing University School of Medicine, Chongqing, China
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35
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Powers JD, Malingen SA, Regnier M, Daniel TL. The Sliding Filament Theory Since Andrew Huxley: Multiscale and Multidisciplinary Muscle Research. Annu Rev Biophys 2021; 50:373-400. [PMID: 33637009 DOI: 10.1146/annurev-biophys-110320-062613] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two groundbreaking papers published in 1954 laid out the theory of the mechanism of muscle contraction based on force-generating interactions between myofilaments in the sarcomere that cause filaments to slide past one another during muscle contraction. The succeeding decades of research in muscle physiology have revealed a unifying interest: to understand the multiscale processes-from atom to organ-that govern muscle function. Such an understanding would have profound consequences for a vast array of applications, from developing new biomimetic technologies to treating heart disease. However, connecting structural and functional properties that are relevant at one spatiotemporal scale to those that are relevant at other scales remains a great challenge. Through a lens of multiscale dynamics, we review in this article current and historical research in muscle physiology sparked by the sliding filament theory.
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Affiliation(s)
- Joseph D Powers
- Department of Bioengineering, University of California San Diego, La Jolla, California 92093, USA
| | - Sage A Malingen
- Department of Biology, University of Washington, Seattle, Washington 98195, USA;
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, Washington 98185, USA
- Center for Translational Muscle Research, University of Washington, Seattle, Washington 98185, USA
| | - Thomas L Daniel
- Department of Biology, University of Washington, Seattle, Washington 98195, USA;
- Department of Bioengineering, University of Washington, Seattle, Washington 98185, USA
- Center for Translational Muscle Research, University of Washington, Seattle, Washington 98185, USA
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36
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Janin A, Januel L, Cazeneuve C, Delinière A, Chevalier P, Millat G. Molecular Diagnosis of Inherited Cardiac Diseases in the Era of Next-Generation Sequencing: A Single Center's Experience Over 5 Years. Mol Diagn Ther 2021; 25:373-385. [PMID: 33954932 DOI: 10.1007/s40291-021-00530-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/17/2021] [Indexed: 12/15/2022]
Abstract
BACKGROUND AND OBJECTIVE Molecular diagnosis in inherited cardiac diseases is challenging because of the significant genetic and clinical heterogeneity. We present a detailed molecular investigation of a cohort of 4185 patients with referrals for inherited cardiac diseases. METHODS Patients suffering from cardiomyopathies (3235 probands), arrhythmia syndromes (760 probands), or unexplained sudden cardiac arrest (190 cases) were analyzed using a next-generation sequencing (NGS) workflow based on a panel of 105 genes involved in sudden cardiac death. RESULTS (Likely) pathogenic variations were identified for approximately 30% of the cohort. Pathogenic copy number variations (CNVs) were detected in approximately 3.1% of patients for whom a (likely) pathogenic variation were identified. A (likely) pathogenic variation was also detected for 21.1% of patients who died from sudden cardiac death. Unexpected variants, including incidental findings, were present for 28 cases. Pathogenic variations were mainly observed in genes with definitive evidence of disease causation. CONCLUSIONS Our study, which comprises over than 4000 probands, is one of most important cohorts reported in inherited cardiac diseases. The global mutation detection rate would be significantly increased by determining the putative pathogenicity of the large number of variants of uncertain significance. Identification of "unexpected" variants also showed the clinical utility of genetic testing in inherited cardiac diseases as they can redirect clinical management and medical resources toward a meaningful precision medicine. In cases with negative result, a WGS approach could be considered, but would probably have a limited impact on mutation detection rate as (likely) pathogenic variations were essentially clustered in genes with strong evidence of disease causation.
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Affiliation(s)
- Alexandre Janin
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Bron Cedex, 69677, Lyon, France.,Institut NeuroMyoGène, CNRS UMR 5310, INSERM U1217, Université Claude Bernard Lyon 1, Lyon, France.,Université de Lyon, 69003, Lyon, France
| | - Louis Januel
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Bron Cedex, 69677, Lyon, France
| | - Cécile Cazeneuve
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Bron Cedex, 69677, Lyon, France
| | - Antoine Delinière
- Université de Lyon, 69003, Lyon, France.,Hôpital Cardiologique Louis Pradel, Service de Rythmologie, Lyon, France
| | - Philippe Chevalier
- Université de Lyon, 69003, Lyon, France.,Hôpital Cardiologique Louis Pradel, Service de Rythmologie, Lyon, France
| | - Gilles Millat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Bron Cedex, 69677, Lyon, France. .,Institut NeuroMyoGène, CNRS UMR 5310, INSERM U1217, Université Claude Bernard Lyon 1, Lyon, France. .,Université de Lyon, 69003, Lyon, France.
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37
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Santos ARMP, Jang Y, Son I, Kim J, Park Y. Recapitulating Cardiac Structure and Function In Vitro from Simple to Complex Engineering. MICROMACHINES 2021; 12:mi12040386. [PMID: 33916254 PMCID: PMC8067203 DOI: 10.3390/mi12040386] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/22/2021] [Accepted: 03/23/2021] [Indexed: 12/12/2022]
Abstract
Cardiac tissue engineering aims to generate in vivo-like functional tissue for the study of cardiac development, homeostasis, and regeneration. Since the heart is composed of various types of cells and extracellular matrix with a specific microenvironment, the fabrication of cardiac tissue in vitro requires integrating technologies of cardiac cells, biomaterials, fabrication, and computational modeling to model the complexity of heart tissue. Here, we review the recent progress of engineering techniques from simple to complex for fabricating matured cardiac tissue in vitro. Advancements in cardiomyocytes, extracellular matrix, geometry, and computational modeling will be discussed based on a technology perspective and their use for preparation of functional cardiac tissue. Since the heart is a very complex system at multiscale levels, an understanding of each technique and their interactions would be highly beneficial to the development of a fully functional heart in cardiac tissue engineering.
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Affiliation(s)
| | | | | | - Jongseong Kim
- Correspondence: (J.K.); (Y.P.); Tel.: +82-10-8858-7260 (J.K.); +82-10-4260-6460 (Y.P.)
| | - Yongdoo Park
- Correspondence: (J.K.); (Y.P.); Tel.: +82-10-8858-7260 (J.K.); +82-10-4260-6460 (Y.P.)
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38
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Januel L, Chanavat V, Rollat-Farnier PA, Bardel C, Nony S, Millat G, Janin A. Whole Sequencing of Most Prevalent Dilated Cardiomyopathy-Causing Genes as a Molecular Strategy to Improve Molecular Diagnosis Efficiency? DNA Cell Biol 2021; 40:491-498. [PMID: 33493017 DOI: 10.1089/dna.2020.6305] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is the most common form of cardiomyopathy and one of the most common causes of heart failure. TTN-truncating variants represent the most common cause of DCM. Similarly, among other prevalent DCM-causing genes, truncating variants were also frequently detected in BAG3, DSP, FLNC, and LMNA. For these four genes, the current study aims to determine the prevalence of deep intronic pathogenic variants that could lead to splice defects. A next-generation sequencing (NGS) workflow based on whole gene sequencing of BAG3, DSP, FLNC, and LMNA of a cohort of 95 DCM patients, for whom no putatively causative point mutations were identified after NGS of a panel of 48 cardiomyopathy-causing genes, was thus performed. Our approach did not lead us to reconsider the molecular diagnosis of any patient of the cohort. This study suggests that deep splice mutations do not account for a significant proportion of DCM cases. In contrast with MYBPC3 in hypertrophic cardiomyopathy cases, NGS of BAG3, DSP, FLNC, and LMNA whole intronic sequences would not significantly improve the efficiency of molecular diagnosis of DCM probands.
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Affiliation(s)
- Louis Januel
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Valérie Chanavat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,CNRS UMR5310, INSERM U1217, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Pierre-Antoine Rollat-Farnier
- Plateforme NGS-HCL, Cellule Bioinformatique, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France
| | - Claire Bardel
- Plateforme NGS-HCL, Cellule Bioinformatique, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,Université de Lyon, Université Lyon 1, CNRS, Laboratoire de Biométrie et Biologie Evolutive, Villeurbanne, France.,Service de Biostatistique-Bioinformatique, Hospices Civils de Lyon, Lyon, France
| | - Severine Nony
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,CNRS UMR5310, INSERM U1217, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Gilles Millat
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,CNRS UMR5310, INSERM U1217, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
| | - Alexandre Janin
- Laboratoire de Cardiogénétique Moléculaire, Centre de Biologie et Pathologie Est, Hospices Civils de Lyon, Lyon, France.,CNRS UMR5310, INSERM U1217, Institut NeuroMyoGène, Université Claude Bernard Lyon 1, Université de Lyon, Lyon, France
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Santiago CF, Huttner IG, Fatkin D. Mechanisms of TTNtv-Related Dilated Cardiomyopathy: Insights from Zebrafish Models. J Cardiovasc Dev Dis 2021; 8:jcdd8020010. [PMID: 33504111 PMCID: PMC7912658 DOI: 10.3390/jcdd8020010] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/19/2021] [Accepted: 01/22/2021] [Indexed: 12/15/2022] Open
Abstract
Dilated cardiomyopathy (DCM) is a common heart muscle disorder characterized by ventricular dilation and contractile dysfunction that is associated with significant morbidity and mortality. New insights into disease mechanisms and strategies for treatment and prevention are urgently needed. Truncating variants in the TTN gene, which encodes the giant sarcomeric protein titin (TTNtv), are the most common genetic cause of DCM, but exactly how TTNtv promote cardiomyocyte dysfunction is not known. Although rodent models have been widely used to investigate titin biology, they have had limited utility for TTNtv-related DCM. In recent years, zebrafish (Danio rerio) have emerged as a powerful alternative model system for studying titin function in the healthy and diseased heart. Optically transparent embryonic zebrafish models have demonstrated key roles of titin in sarcomere assembly and cardiac development. The increasing availability of sophisticated imaging tools for assessment of heart function in adult zebrafish has revolutionized the field and opened new opportunities for modelling human genetic disorders. Genetically modified zebrafish that carry a human A-band TTNtv have now been generated and shown to spontaneously develop DCM with age. This zebrafish model will be a valuable resource for elucidating the phenotype modifying effects of genetic and environmental factors, and for exploring new drug therapies.
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Affiliation(s)
- Celine F. Santiago
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Inken G. Huttner
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
| | - Diane Fatkin
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia; (C.F.S.); (I.G.H.)
- St. Vincent’s Clinical School, Faculty of Medicine, UNSW Sydney, Kensington, NSW 2052, Australia
- Cardiology Department, St. Vincent’s Hospital, Darlinghurst, NSW 2010, Australia
- Correspondence:
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40
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Does Cronos hypothesis contribute to the understanding the role of Titin in dilated cardiomyopathy? Int J Cardiol 2020; 321:129. [PMID: 32712113 DOI: 10.1016/j.ijcard.2020.07.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 07/22/2020] [Indexed: 11/21/2022]
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41
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A Novel Recessive Mutation in SPEG Causes Early Onset Dilated Cardiomyopathy. PLoS Genet 2020; 16:e1009000. [PMID: 32925938 PMCID: PMC7571691 DOI: 10.1371/journal.pgen.1009000] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 10/19/2020] [Accepted: 07/21/2020] [Indexed: 01/05/2023] Open
Abstract
Dilated cardiomyopathy (DCM) is a common cause of heart failure and sudden cardiac death. It has been estimated that up to half of DCM cases are hereditary. Mutations in more than 50 genes, primarily autosomal dominant, have been reported. Although rare, recessive mutations are thought to contribute considerably to DCM, especially in young children. Here we identified a novel recessive mutation in the striated muscle enriched protein kinase (SPEG, p. E1680K) gene in a family with nonsyndromic, early onset DCM. To ascertain the pathogenicity of this mutation, we generated SPEG E1680K homozygous mutant human induced pluripotent stem cell derived cardiomyocytes (iPSC-CMs) using CRISPR/Cas9-mediated genome editing. Functional studies in mutant iPSC-CMs showed aberrant calcium homeostasis, impaired contractility, and sarcomeric disorganization, recapitulating the hallmarks of DCM. By combining genetic analysis with human iPSCs, genome editing, and functional assays, we identified SPEG E1680K as a novel mutation associated with early onset DCM and provide evidence for its pathogenicity in vitro. Our study provides a conceptual paradigm for establishing genotype-phenotype associations in DCM with autosomal recessive inheritance.
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42
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Under construction: The dynamic assembly, maintenance, and degradation of the cardiac sarcomere. J Mol Cell Cardiol 2020; 148:89-102. [PMID: 32920010 DOI: 10.1016/j.yjmcc.2020.08.018] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 08/20/2020] [Accepted: 08/22/2020] [Indexed: 12/11/2022]
Abstract
The sarcomere is the basic contractile unit of striated muscle and is a highly ordered protein complex with the actin and myosin filaments at its core. Assembling the sarcomere constituents into this organized structure in development, and with muscle growth as new sarcomeres are built, is a complex process coordinated by numerous factors. Once assembled, the sarcomere requires constant maintenance as its continuous contraction is accompanied by elevated mechanical, thermal, and oxidative stress, which predispose proteins to misfolding and toxic aggregation. To prevent protein misfolding and maintain sarcomere integrity, the sarcomere is monitored by an assortment of protein quality control (PQC) mechanisms. The need for effective PQC is heightened in cardiomyocytes which are terminally differentiated and must survive for many years while preserving optimal mechanical output. To prevent toxic protein aggregation, molecular chaperones stabilize denatured sarcomere proteins and promote their refolding. However, when old and misfolded proteins cannot be salvaged by chaperones, they must be recycled via degradation pathways: the calpain and ubiquitin-proteasome systems, which operate under basal conditions, and the stress-responsive autophagy-lysosome pathway. Mutations to and deficiency of the molecular chaperones and associated factors charged with sarcomere maintenance commonly lead to sarcomere structural disarray and the progression of heart disease, highlighting the necessity of effective sarcomere PQC for maintaining cardiac function. This review focuses on the dynamic regulation of assembly and turnover at the sarcomere with an emphasis on the chaperones involved in these processes and describes the alterations to chaperones - through mutations and deficient expression - implicated in disease progression to heart failure.
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43
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Swist S, Unger A, Li Y, Vöge A, von Frieling-Salewsky M, Skärlén Å, Cacciani N, Braun T, Larsson L, Linke WA. Maintenance of sarcomeric integrity in adult muscle cells crucially depends on Z-disc anchored titin. Nat Commun 2020; 11:4479. [PMID: 32900999 PMCID: PMC7478974 DOI: 10.1038/s41467-020-18131-2] [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: 06/29/2019] [Accepted: 08/04/2020] [Indexed: 12/14/2022] Open
Abstract
The giant protein titin is thought to be required for sarcomeric integrity in mature myocytes, but direct evidence for this hypothesis is limited. Here, we describe a mouse model in which Z-disc-anchored TTN is depleted in adult skeletal muscles. Inactivation of TTN causes sarcomere disassembly and Z-disc deformations, force impairment, myocyte de-stiffening, upregulation of TTN-binding mechanosensitive proteins and activation of protein quality-control pathways, concomitant with preferential loss of thick-filament proteins. Interestingly, expression of the myosin-bound Cronos-isoform of TTN, generated from an alternative promoter not affected by the targeting strategy, does not prevent deterioration of sarcomere formation and maintenance. Finally, we demonstrate that loss of Z-disc-anchored TTN recapitulates muscle remodeling in critical illness ‘myosinopathy’ patients, characterized by TTN-depletion and loss of thick filaments. We conclude that full-length TTN is required to integrate Z-disc and A-band proteins into the mature sarcomere, a function that is lost when TTN expression is pathologically lowered. Titin is considered an integrator of muscle cell proteins but direct evidence is limited. Here, titin is inactivated in adult mouse muscles, which causes sarcomere disassembly, protein mis-expression and force impairment, recapitulating key alterations in critical illness myopathy patient muscles.
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Affiliation(s)
- Sandra Swist
- Department of Systems Physiology, Ruhr University Bochum, D-44780, Bochum, Germany.
| | - Andreas Unger
- Institute of Physiology II, University of Munster, D-48149, Munster, Germany
| | - Yong Li
- Institute of Physiology II, University of Munster, D-48149, Munster, Germany
| | - Anja Vöge
- Department of Systems Physiology, Ruhr University Bochum, D-44780, Bochum, Germany
| | | | - Åsa Skärlén
- Department of Clinical Neuroscience, Clinical Neurophysiology, Karolinska Institute, SE-171 77, Stockholm, Sweden
| | - Nicola Cacciani
- Department of Physiology and Pharmacology, Karolinska Institute, SE-171 77, Stockholm, Sweden
| | - Thomas Braun
- Department of Cardiac Development and Remodeling, Max Planck Institute for Heart and Lung Research, D-61231, Bad Nauheim, Germany
| | - Lars Larsson
- Department of Physiology and Pharmacology, Karolinska Institute, SE-171 77, Stockholm, Sweden
| | - Wolfgang A Linke
- Institute of Physiology II, University of Munster, D-48149, Munster, Germany.
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Ito M, Nomura S, Morita H, Komuro I. Trends and Limitations in the Assessment of the Contractile Properties of Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes From Patients With Dilated Cardiomyopathy. Front Cardiovasc Med 2020; 7:154. [PMID: 33102534 PMCID: PMC7494730 DOI: 10.3389/fcvm.2020.00154] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 07/22/2020] [Indexed: 12/14/2022] Open
Abstract
The application of human induced pluripotent stem cell-derived cardiomyocytes (hiPSCMs) from patients is expected in disease modeling and drug screening in vitro. Dilated cardiomyopathy (DCM) is an intractable disease characterized by the impairment of systolic function and leads to severe heart failure. A number of researchers have focused on disease modeling of DCM and reproduced its pathologic phenotypes in hiPSCMs, but a robust method to evaluate the contractile properties of cardiomyocytes in vitro has not been standardized. In addition, it is unknown whether the throughput of measurements and analyses could be increased sufficiently for compound screening. Here, we reviewed the articles in which the contractile abnormalities of DCM hiPSCMs were recapitulated and assessed the trends and problems in sample preparation and evaluation. We found that single-cell level analysis was ineffective in some cases, and a tissue engineering approach has become dominant recently because of its increased efficiency in reproducing impaired contractility. We also examined two commercially available automated measurement devices with moderate throughput for motion analysis using two-dimensional hiPSCM sheets composed of originally established DCM hiPSCMs. As a result, both of the tested devices, an impedance analyzer and a video image-based cell motion analyzer, were not effective in detecting the expected reduction of contractility in the DCM clone. These findings collectively suggest that a tissue engineering approach could expand the potential of disease modeling with hiPSCMs, and so far, appropriate methods for in vitro force measurement with sufficient throughput, but without sacrificing physiological fidelity, are awaited.
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Affiliation(s)
- Masamichi Ito
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Seitaro Nomura
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Hiroyuki Morita
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Issei Komuro
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Modifications of Titin Contribute to the Progression of Cardiomyopathy and Represent a Therapeutic Target for Treatment of Heart Failure. J Clin Med 2020; 9:jcm9092770. [PMID: 32859027 PMCID: PMC7564493 DOI: 10.3390/jcm9092770] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 12/20/2022] Open
Abstract
Titin is the largest human protein and an essential component of the cardiac sarcomere. With multiple immunoglobulin(Ig)-like domains that serve as molecular springs, titin contributes significantly to the passive tension, systolic function, and diastolic function of the heart. Mutations leading to early termination of titin are the most common genetic cause of dilated cardiomyopathy. Modifications of titin, which change protein length, and relative stiffness affect resting tension of the ventricle and are associated with acquired forms of heart failure. Transcriptional and post-translational changes that increase titin’s length and extensibility, making the sarcomere longer and softer, are associated with systolic dysfunction and left ventricular dilation. Modifications of titin that decrease its length and extensibility, making the sarcomere shorter and stiffer, are associated with diastolic dysfunction in animal models. There has been significant progress in understanding the mechanisms by which titin is modified. As molecular pathways that modify titin’s mechanical properties are elucidated, they represent therapeutic targets for treatment of both systolic and diastolic dysfunction. In this article, we review titin’s contribution to normal cardiac physiology, the pathophysiology of titin truncation variations leading to dilated cardiomyopathy, and transcriptional and post-translational modifications of titin. Emphasis is on how modification of titin can be utilized as a therapeutic target for treatment of heart failure.
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Comprehensive analysis reveals a six-gene signature and associated drugs in mimic inguinal hernia model. Hernia 2020; 24:1211-1219. [DOI: 10.1007/s10029-020-02213-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 05/04/2020] [Indexed: 02/06/2023]
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Pioner JM, Fornaro A, Coppini R, Ceschia N, Sacconi L, Donati MA, Favilli S, Poggesi C, Olivotto I, Ferrantini C. Advances in Stem Cell Modeling of Dystrophin-Associated Disease: Implications for the Wider World of Dilated Cardiomyopathy. Front Physiol 2020; 11:368. [PMID: 32477154 PMCID: PMC7235370 DOI: 10.3389/fphys.2020.00368] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 03/30/2020] [Indexed: 12/26/2022] Open
Abstract
Familial dilated cardiomyopathy (DCM) is mostly caused by mutations in genes encoding cytoskeletal and sarcomeric proteins. In the pediatric population, DCM is the predominant type of primitive myocardial disease. A severe form of DCM is associated with mutations in the DMD gene encoding dystrophin, which are the cause of Duchenne Muscular Dystrophy (DMD). DMD-associated cardiomyopathy is still poorly understood and orphan of a specific therapy. In the last 5 years, a rise of interest in disease models using human induced pluripotent stem cells (hiPSCs) has led to more than 50 original studies on DCM models. In this review paper, we provide a comprehensive overview on the advances in DMD cardiomyopathy disease modeling and highlight the most remarkable findings obtained from cardiomyocytes differentiated from hiPSCs of DMD patients. We will also describe how hiPSCs based studies have contributed to the identification of specific myocardial disease mechanisms that may be relevant in the pathogenesis of DCM, representing novel potential therapeutic targets.
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Affiliation(s)
- Josè Manuel Pioner
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | | | - Raffaele Coppini
- Department of NeuroFarBa, Università degli Studi di Firenze, Florence, Italy
| | - Nicole Ceschia
- Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy
| | - Leonardo Sacconi
- LENS, Università degli Studi di Firenze and National Institute of Optics (INO-CNR), Florence, Italy
| | | | - Silvia Favilli
- Pediatric Cardiology, Meyer Children's Hospital, Florence, Italy
| | - Corrado Poggesi
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
| | - Iacopo Olivotto
- Cardiomyopathy Unit, Careggi University Hospital, Florence, Italy
| | - Cecilia Ferrantini
- Division of Physiology, Department of Experimental and Clinical Medicine, Università degli Studi di Firenze, Florence, Italy
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Obenaus AM, Mollica MY, Sniadecki NJ. (De)form and Function: Measuring Cellular Forces with Deformable Materials and Deformable Structures. Adv Healthc Mater 2020; 9:e1901454. [PMID: 31951099 PMCID: PMC7274881 DOI: 10.1002/adhm.201901454] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 12/04/2019] [Indexed: 12/29/2022]
Abstract
The ability for biological cells to produce mechanical forces is important for the development, function, and homeostasis of tissue. The measurement of cellular forces is not a straightforward task because individual cells are microscopic in size and the forces they produce are at the nanonewton scale. Consequently, studies in cell mechanics rely on advanced biomaterials or flexible structures that permit one to infer these forces by the deformation they impart on the material or structure. Herein, the scientific progression on the use of deformable materials and deformable structures to measure cellular forces are reviewed. The findings and insights made possible with these approaches in the field of cell mechanics are summarized.
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Affiliation(s)
- Ava M Obenaus
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA
| | - Molly Y Mollica
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
| | - Nathan J Sniadecki
- Department of Mechanical Engineering, University of Washington, Seattle, WA, 98195, USA
- Department of Bioengineering, University of Washington, Seattle, WA, 98195, USA
- Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA, 98195, USA
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Nikonova E, Kao SY, Spletter ML. Contributions of alternative splicing to muscle type development and function. Semin Cell Dev Biol 2020; 104:65-80. [PMID: 32070639 DOI: 10.1016/j.semcdb.2020.02.003] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/05/2020] [Accepted: 02/07/2020] [Indexed: 12/30/2022]
Abstract
Animals possess a wide variety of muscle types that support different kinds of movements. Different muscles have distinct locations, morphologies and contractile properties, raising the question of how muscle diversity is generated during development. Normal aging processes and muscle disorders differentially affect particular muscle types, thus understanding how muscles normally develop and are maintained provides insight into alterations in disease and senescence. As muscle structure and basic developmental mechanisms are highly conserved, many important insights into disease mechanisms in humans as well as into basic principles of muscle development have come from model organisms such as Drosophila, zebrafish and mouse. While transcriptional regulation has been characterized to play an important role in myogenesis, there is a growing recognition of the contributions of alternative splicing to myogenesis and the refinement of muscle function. Here we review our current understanding of muscle type specific alternative splicing, using examples of isoforms with distinct functions from both vertebrates and Drosophila. Future exploration of the vast potential of alternative splicing to fine-tune muscle development and function will likely uncover novel mechanisms of isoform-specific regulation and a more holistic understanding of muscle development, disease and aging.
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Affiliation(s)
- Elena Nikonova
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany
| | - Shao-Yen Kao
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany
| | - Maria L Spletter
- Biomedical Center, Department of Physiological Chemistry, Ludwig-Maximilians-Universität München, Großhaderner Str. 9, 82152 Martinsried-Planegg, Germany; Center for Integrated Protein Science Munich (CIPSM) at the Department of Chemistry, Ludwig-Maximilians-Universität München, Munich, Germany.
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