1
|
Guo J, Jiang H, Schuftan D, Moreno JD, Ramahdita G, Aryan L, Bhagavan D, Silva J, Huebsch N. Substrate mechanics unveil early structural and functional pathology in iPSC micro-tissue models of hypertrophic cardiomyopathy. iScience 2024; 27:109954. [PMID: 38827401 PMCID: PMC11141149 DOI: 10.1016/j.isci.2024.109954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/22/2024] [Accepted: 05/08/2024] [Indexed: 06/04/2024] Open
Abstract
Hypertension is a major cause of morbidity and mortality in patients with hypertrophic cardiomyopathy (HCM), suggesting a potential role for mechanics in HCM pathogenesis. Here, we developed an in vitro physiological model to investigate how mechanics acts together with HCM-linked myosin binding protein C (MYBPC3) mutations to trigger disease. Micro-heart muscles (μHM) were engineered from induced pluripotent stem cell (iPSC)-derived cardiomyocytes bearing MYBPC3+/- mutations and challenged to contract against substrates of different elasticity. μHMs that worked against substrates with stiffness at or exceeding the stiffness of healthy adult heart muscle exhibited several hallmarks of HCM, including cellular hypertrophy, impaired contractile energetics, and maladaptive calcium handling. Remarkably, we discovered changes in troponin C and T localization in MYBPC3+/- μHM that were entirely absent in 2D culture. Pharmacologic studies suggested that excessive Ca2+ intake through membrane-embedded channels underlie the observed electrophysiological abnormalities. These results illustrate the power of physiologically relevant engineered tissue models to study inherited disease with iPSC technology.
Collapse
Affiliation(s)
- Jingxuan Guo
- Department of Mechanical Engineering and Material Science, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Huanzhu Jiang
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - David Schuftan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Jonathan D. Moreno
- Division of Cardiology, Department of Medicine, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Ghiska Ramahdita
- Department of Mechanical Engineering and Material Science, Washington University in Saint Louis, Saint Louis, MO 63130, USA
- NSF Science and Technology Center for Engineering Mechanobiology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Lavanya Aryan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Druv Bhagavan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Jonathan Silva
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Nathaniel Huebsch
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
- NSF Science and Technology Center for Engineering Mechanobiology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
- Center for Cardiovascular Research, Center for Regenerative Medicine, Center for Investigation of Membrane Excitability Diseases, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| |
Collapse
|
2
|
Tanner BCW, Palmer BM, Chung CS. Strain rate of stretch affects crossbridge detachment during relaxation of intact cardiac trabeculae. PLoS One 2024; 19:e0297212. [PMID: 38437198 PMCID: PMC10911597 DOI: 10.1371/journal.pone.0297212] [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: 10/13/2023] [Accepted: 12/29/2023] [Indexed: 03/06/2024] Open
Abstract
Mechanical Control of Relaxation refers to the dependence of myocardial relaxation on the strain rate just prior to relaxation, but the mechanisms of enhanced relaxation are not well characterized. This study aimed to characterize how crossbridge kinetics varied with strain rate and time-to-stretch as the myocardium relaxed in early diastole. Ramp-stretches of varying rates (amplitude = 1% muscle length) were applied to intact rat cardiac trabeculae following a load-clamp at 50% of the maximal developed twitch force, which provides a first-order estimate of ejection and coupling to an afterload. The resultant stress-response was calculated as the difference between the time-dependent stress profile between load-clamped twitches with and without a ramp-stretch. The stress-response exhibited features of the step-stretch response of activated, permeabilized myocardium, such as distortion-dependent peak stress, rapid force decay related to crossbridge detachment, and stress recovery related to crossbridge recruitment. The peak stress was strain rate dependent, but the minimum stress and the time-to-minimum stress values were not. The initial rapid change in the stress-response indicates enhanced crossbridge detachment at higher strain rates during relaxation in intact cardiac trabeculae. Physiologic considerations, such as time-varying calcium, are discussed as potential limitations to fitting these data with traditional distortion-recruitment models of crossbridge activity.
Collapse
Affiliation(s)
- Bertrand C. W. Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington, United States of America
| | - Bradley M. Palmer
- Department of Molecular Physiology and Biophysics, University of Vermont, Burlington, Vermont, United States of America
| | - Charles S. Chung
- Department of Physiology, Wayne State University, Detroit, Michigan, United States of America
| |
Collapse
|
3
|
Janssens JV, Raaijmakers AJA, Weeks KL, Bell JR, Mellor KM, Curl CL, Delbridge LMD. The cardiomyocyte origins of diastolic dysfunction: cellular components of myocardial "stiffness". Am J Physiol Heart Circ Physiol 2024; 326:H584-H598. [PMID: 38180448 DOI: 10.1152/ajpheart.00334.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 12/07/2023] [Accepted: 12/21/2023] [Indexed: 01/06/2024]
Abstract
The impaired ability of the heart to relax and stretch to accommodate venous return is generally understood to represent a state of "diastolic dysfunction" and often described using the all-purpose noun "stiffness." Despite the now common qualitative usage of this term in fields of cardiac patho/physiology, the specific quantitative concept of stiffness as a molecular and biophysical entity with real practical interpretation in healthy and diseased hearts is sometimes obscure. The focus of this review is to characterize the concept of cardiomyocyte stiffness and to develop interpretation of "stiffness" attributes at the cellular and molecular levels. Here, we consider "stiffness"-related terminology interpretation and make links between cardiomyocyte stiffness and aspects of functional and structural cardiac performance. We discuss cross bridge-derived stiffness sources, considering the contributions of diastolic myofilament activation and impaired relaxation. This includes commentary relating to the role of cardiomyocyte Ca2+ flux and Ca2+ levels in diastole, the troponin-tropomyosin complex role as a Ca2+ effector in diastole, the myosin ADP dissociation rate as a modulator of cross bridge attachment and regulation of cross-bridge attachment by myosin binding protein C. We also discuss non-cross bridge-derived stiffness sources, including the titin sarcomeric spring protein, microtubule and intermediate filaments, and cytoskeletal extracellular matrix interactions. As the prevalence of conditions involving diastolic heart failure has escalated, a more sophisticated understanding of the molecular, cellular, and tissue determinants of cardiomyocyte stiffness offers potential to develop imaging and molecular intervention tools.
Collapse
Affiliation(s)
- Johannes V Janssens
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Antonia J A Raaijmakers
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Kate L Weeks
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
- Baker Department of Cardiometabolic Health, University of Melbourne, Melbourne, Victoria, Australia
- Department of Diabetes, Monash University, Parkville, Victoria, Australia
| | - James R Bell
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Microbiology, Anatomy, Physiology and Pharmacology, La Trobe University, Melbourne, Victoria, Australia
| | - Kimberley M Mellor
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
- Department of Physiology, University of Auckland, Auckland, New Zealand
- Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Claire L Curl
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
| | - Lea M D Delbridge
- Department of Anatomy and Physiology, University of Melbourne, Melbourne, Victoria, Australia
| |
Collapse
|
4
|
Guo G, Wang L, Li X, Fu W, Cao J, Zhang J, Liu Y, Liu M, Wang M, Zhao G, Zhao X, Zhou Y, Niu S, Liu G, Zhang Y, Dong J, Tao H, Zhao X. Enhanced myofilament calcium sensitivity aggravates abnormal calcium handling and diastolic dysfunction in patient-specific induced pluripotent stem cell-derived cardiomyocytes with MYH7 mutation. Cell Calcium 2024; 117:102822. [PMID: 38101154 DOI: 10.1016/j.ceca.2023.102822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/04/2023] [Accepted: 11/06/2023] [Indexed: 12/17/2023]
Abstract
Hypertrophic cardiomyopathy (HCM), the most common inherited heart disease, is frequently caused by mutations in the β-cardiac myosin heavy chain gene (MYH7). Abnormal calcium handling and diastolic dysfunction are archetypical features of HCM caused by MYH7 gene mutations. However, the mechanism of how MYH7 mutations leads to these features remains unclear, which inhibits the development of effective therapies. Initially, cardiomyocytes were generated from induced pluripotent stem cells from an eight-year-old girl diagnosed with HCM carrying a MYH7(C.1063 G>A) heterozygous mutation(mutant-iPSC-CMs) and mutation-corrected isogenic iPSCs(control-iPSC-CMs) in the present study. Next, we compared phenotype of mutant-iPSC-CMs to that of control-iPSC-CMs, by assessing their morphology, hypertrophy-related genes expression, calcium handling, diastolic function and myofilament calcium sensitivity at days 15 and 40 respectively. Finally, to better understand increased myofilament Ca2+ sensitivity as a central mechanism of central pathogenicity in HCM, inhibition of calcium sensitivity with mavacamten can improveed cardiomyocyte hypertrophy. Mutant-iPSC-CMs exhibited enlarged areas, increased sarcomere disarray, enhanced expression of hypertrophy-related genes proteins, abnormal calcium handling, diastolic dysfunction and increased myofilament calcium sensitivity at day 40, but only significant increase in calcium sensitivity and mild diastolic dysfunction at day 15. Increased calcium sensitivity by levosimendan aggravates cardiomyocyte hypertrophy phenotypes such as expression of hypertrophy-related genes, abnormal calcium handling and diastolic dysfunction, while inhibition of calcium sensitivity significantly improves cardiomyocyte hypertrophy phenotypes in mutant-iPSC-CMs, suggesting increased myofilament calcium sensitivity is the primary mechanisms for MYH7 mutations pathogenesis. Our studies have uncovered a pathogenic mechanism of HCM caused by MYH7 gene mutations through which enhanced myofilament calcium sensitivity aggravates abnormal calcium handling and diastolic dysfunction. Correction of the myofilament calcium sensitivity was found to be an effective method for treating the development of HCM phenotype in vitro.
Collapse
Affiliation(s)
- Guangli Guo
- Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China
| | - Lu Wang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Xiaowei Li
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Wanrong Fu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jinhua Cao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jianchao Zhang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Yangyang Liu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Mengduan Liu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Mengyu Wang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Guojun Zhao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Xi Zhao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Yangfan Zhou
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China
| | - Shaohui Niu
- Department of Cardiology, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, 450000, China
| | - Gangqiong Liu
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Yanzhou Zhang
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Jianzeng Dong
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China; Department of Cardiology, Beijing Anzhen Hospital, Capital Medical University, National Clinical Research Centre for Cardiovascular Diseases, No. 2 Beijing Anzhen Road, Chaoyang District, Beijing 100029, China.
| | - Hailong Tao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
| | - Xiaoyan Zhao
- Department of Cardiology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China; Henan Key Laboratory of Hereditary Cardiovascular Diseases, Zhengzhou, 450052, China.
| |
Collapse
|
5
|
Guo J, Jiang H, Schuftan D, Moreno JD, Ramahdita G, Aryan L, Bhagavan D, Silva J, Huebsch N. Mechanical Resistance to Micro-Heart Tissue Contractility unveils early Structural and Functional Pathology in iPSC Models of Hypertrophic Cardiomyopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.30.564856. [PMID: 37961198 PMCID: PMC10634965 DOI: 10.1101/2023.10.30.564856] [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
Hypertrophic cardiomyopathy is the most common cause of sudden death in the young. Because the disease exhibits variable penetrance, there are likely nongenetic factors that contribute to the manifestation of the disease phenotype. Clinically, hypertension is a major cause of morbidity and mortality in patients with HCM, suggesting a potential synergistic role for the sarcomeric mutations associated with HCM and mechanical stress on the heart. We developed an in vitro physiological model to investigate how the afterload that the heart muscle works against during contraction acts together with HCM-linked MYBPC3 mutations to trigger a disease phenotype. Micro-heart muscle arrays (μHM) were engineered from iPSC-derived cardiomyocytes bearing MYBPC3 loss-of-function mutations and challenged to contract against mechanical resistance with substrates stiffnesses ranging from the of embryonic hearts (0.4 kPa) up to the stiffness of fibrotic adult hearts (114 kPa). Whereas MYBPC3 +/- iPSC-cardiomyocytes showed little signs of disease pathology in standard 2D culture, μHMs that included components of afterload revealed several hallmarks of HCM, including cellular hypertrophy, impaired contractile energetics, and maladaptive calcium handling. Remarkably, we discovered changes in troponin C and T localization in the MYBPC3 +/- μHM that were entirely absent in 2D culture. Pharmacologic studies suggested that excessive Ca 2+ intake through membrane-embedded channels, rather than sarcoplasmic reticulum Ca 2+ ATPase (SERCA) dysfunction or Ca 2+ buffering at myofilaments underlie the observed electrophysiological abnormalities. These results illustrate the power of physiologically relevant engineered tissue models to study inherited disease mechanisms with iPSC technology.
Collapse
|
6
|
Hawey C, Bourque K, Alim K, Derish I, Rody E, Khan K, Gendron N, Cecere R, Giannetti N, Hébert TE. Measuring Single-Cell Calcium Dynamics Using a Myofilament-Localized Optical Biosensor in hiPSC-CMs Derived from DCM Patients. Cells 2023; 12:2526. [PMID: 37947605 PMCID: PMC10647603 DOI: 10.3390/cells12212526] [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: 09/14/2023] [Revised: 10/18/2023] [Accepted: 10/24/2023] [Indexed: 11/12/2023] Open
Abstract
Synchronized contractions of cardiomyocytes within the heart are tightly coupled to electrical stimulation known as excitation-contraction coupling. Calcium plays a key role in this process and dysregulated calcium handling can significantly impair cardiac function and lead to the development of cardiomyopathies and heart failure. Here, we describe a method and analytical technique to study myofilament-localized calcium signaling using the intensity-based fluorescent biosensor, RGECO-TnT. Dilated cardiomyopathy is a heart muscle disease that negatively impacts the heart's contractile function following dilatation of the left ventricle. We demonstrate how this biosensor can be used to characterize 2D hiPSC-CMs monolayers generated from a healthy control subject compared to two patients diagnosed with dilated cardiomyopathy. Lastly, we provide a step-by-step guide for single-cell data analysis and describe a custom Transient Analysis application, specifically designed to quantify features of calcium transients. All in all, we explain how this analytical approach can be applied to phenotype hiPSC-CM behaviours and stratify patient responses to identify perturbations in calcium signaling.
Collapse
Affiliation(s)
- Cara Hawey
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada; (C.H.); (K.B.); (K.A.)
| | - Kyla Bourque
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada; (C.H.); (K.B.); (K.A.)
| | - Karima Alim
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada; (C.H.); (K.B.); (K.A.)
| | - Ida Derish
- Research Institute, McGull University Hospital Centre, 1001 Decarie Blvd, Montréal, QC H4A 3J1, Canada; (I.D.); (E.R.); (K.K.); (N.G.); (R.C.); (N.G.)
| | - Elise Rody
- Research Institute, McGull University Hospital Centre, 1001 Decarie Blvd, Montréal, QC H4A 3J1, Canada; (I.D.); (E.R.); (K.K.); (N.G.); (R.C.); (N.G.)
| | - Kashif Khan
- Research Institute, McGull University Hospital Centre, 1001 Decarie Blvd, Montréal, QC H4A 3J1, Canada; (I.D.); (E.R.); (K.K.); (N.G.); (R.C.); (N.G.)
| | - Natalie Gendron
- Research Institute, McGull University Hospital Centre, 1001 Decarie Blvd, Montréal, QC H4A 3J1, Canada; (I.D.); (E.R.); (K.K.); (N.G.); (R.C.); (N.G.)
| | - Renzo Cecere
- Research Institute, McGull University Hospital Centre, 1001 Decarie Blvd, Montréal, QC H4A 3J1, Canada; (I.D.); (E.R.); (K.K.); (N.G.); (R.C.); (N.G.)
| | - Nadia Giannetti
- Research Institute, McGull University Hospital Centre, 1001 Decarie Blvd, Montréal, QC H4A 3J1, Canada; (I.D.); (E.R.); (K.K.); (N.G.); (R.C.); (N.G.)
| | - Terence E. Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, QC H3G 1Y6, Canada; (C.H.); (K.B.); (K.A.)
| |
Collapse
|
7
|
Eisner D, Neher E, Taschenberger H, Smith G. Physiology of intracellular calcium buffering. Physiol Rev 2023; 103:2767-2845. [PMID: 37326298 DOI: 10.1152/physrev.00042.2022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/08/2023] [Accepted: 06/11/2023] [Indexed: 06/17/2023] Open
Abstract
Calcium signaling underlies much of physiology. Almost all the Ca2+ in the cytoplasm is bound to buffers, with typically only ∼1% being freely ionized at resting levels in most cells. Physiological Ca2+ buffers include small molecules and proteins, and experimentally Ca2+ indicators will also buffer calcium. The chemistry of interactions between Ca2+ and buffers determines the extent and speed of Ca2+ binding. The physiological effects of Ca2+ buffers are determined by the kinetics with which they bind Ca2+ and their mobility within the cell. The degree of buffering depends on factors such as the affinity for Ca2+, the Ca2+ concentration, and whether Ca2+ ions bind cooperatively. Buffering affects both the amplitude and time course of cytoplasmic Ca2+ signals as well as changes of Ca2+ concentration in organelles. It can also facilitate Ca2+ diffusion inside the cell. Ca2+ buffering affects synaptic transmission, muscle contraction, Ca2+ transport across epithelia, and the killing of bacteria. Saturation of buffers leads to synaptic facilitation and tetanic contraction in skeletal muscle and may play a role in inotropy in the heart. This review focuses on the link between buffer chemistry and function and how Ca2+ buffering affects normal physiology and the consequences of changes in disease. As well as summarizing what is known, we point out the many areas where further work is required.
Collapse
Affiliation(s)
- David Eisner
- Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Erwin Neher
- Membrane Biophysics Laboratory, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
| | - Holger Taschenberger
- Department of Molecular Neurobiology, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Godfrey Smith
- School of Cardiovascular and Metabolic Health, College of Medical, Veterinary, and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| |
Collapse
|
8
|
Hu Y, Zhang S, Lou H, Mikaye MS, Xu R, Meng Z, Du M, Tang P, Chen Z, Chen Y, Liu X, Du Z, Zhang Y. Aloe-Emodin Derivative, an Anthraquinone Compound, Attenuates Pyroptosis by Targeting NLRP3 Inflammasome in Diabetic Cardiomyopathy. Pharmaceuticals (Basel) 2023; 16:1275. [PMID: 37765083 PMCID: PMC10536457 DOI: 10.3390/ph16091275] [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: 08/03/2023] [Revised: 08/27/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Diabetic cardiomyopathy (DCM) is widely recognized as a major contributing factor to the development of heart failure in patients with diabetes. Previous studies have demonstrated the potential benefits of traditional herbal medicine for alleviating the symptoms of cardiomyopathy. We have chemically designed and synthesized a novel compound called aloe-emodin derivative (AED), which belongs to the aloe-emodin (AE) family of compounds. AED was formed by covalent binding of monomethyl succinate to the anthraquinone mother nucleus of AE using chemical synthesis techniques. The purpose of this study was to investigate the effects and mechanisms of AED in treating DCM. We induced type 2 diabetes in Sprague-Dawley (SD) rats by administering a high-fat diet and streptozotocin (STZ) injections. The rats were randomly divided into six groups: control, DCM, AED low concentration (50 mg/kg/day), AED high concentration (100 mg/kg/day), AE (100 mg/kg/day), and positive control (glyburide, 2 mg/kg/day) groups. There were eight rats in each group. The rats that attained fasting blood glucose of ˃16.7 mmol/L were considered successful models. We observed significant improvements in cardiac function in the DCM rats with both AED and AE following four weeks of intragastric treatment. However, AED had a more pronounced therapeutic effect on DCM compared to AE. AED exhibited an inhibitory effect on the inflammatory response in the hearts of DCM rats and high-glucose-treated H9C2 cells by suppressing the pyroptosis pathway mediated by the nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain 3 (NLRP3) inflammasome. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis of differentially expressed genes showed a significant enrichment in the NOD-like receptor signaling pathway compared to the high-glucose group. Furthermore, overexpression of NLRP3 effectively reversed the anti-pyroptosis effects of AED in high-glucose-treated H9C2 cells. This study is the first to demonstrate that AED possesses the ability to inhibit myocardial pyroptosis in DCM. Targeting the pyroptosis pathway mediated by the NLRP3 inflammasome could provide a promising therapeutic strategy to enhance our understanding and treatment of DCM.
Collapse
Affiliation(s)
- Yingying Hu
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Shuqian Zhang
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Han Lou
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Monayo Seth Mikaye
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Run Xu
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Ziyu Meng
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Menghan Du
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Pingping Tang
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Zhouxiu Chen
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Yongchao Chen
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
| | - Xin Liu
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
- Research Unit of Noninfectious Chronic Diseases in Frigid Zone, Chinese Academy of Medical Sciences, 2019RU070, Harbin 150081, China
| | - Zhimin Du
- Institute of Clinical Pharmacology, The Second Affliated Hospital of Harbin Medical University (University Key Laboratory of Drug Research, Heilongjiang Province), Harbin 150086, China
- Department of Clinical Pharmacology College of Pharmacy, Harbin Medical University, Harbin 150081, China
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau 999078, China
| | - Yong Zhang
- Department of Pharmacology (The State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin 150086, China
- Research Unit of Noninfectious Chronic Diseases in Frigid Zone, Chinese Academy of Medical Sciences, 2019RU070, Harbin 150081, China
- Institute of Metabolic Disease, Heilongjiang Academy of Medical Science, Harbin 150086, China
| |
Collapse
|
9
|
Nag S, Gollapudi SK, Del Rio CL, Spudich JA, McDowell R. Mavacamten, a precision medicine for hypertrophic cardiomyopathy: From a motor protein to patients. SCIENCE ADVANCES 2023; 9:eabo7622. [PMID: 37506209 DOI: 10.1126/sciadv.abo7622] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder characterized by left ventricular hypertrophy, hyperdynamic contraction, and impaired relaxation of the heart. These functional derangements arise directly from altered sarcomeric function due to either mutations in genes encoding sarcomere proteins, or other defects such as abnormal energetics. Current treatment options do not directly address this causal biology but focus on surgical and extra-sarcomeric (sarcolemmal) pharmacological symptomatic relief. Mavacamten (formerly known as MYK-461), is a small molecule designed to regulate cardiac function at the sarcomere level by selectively but reversibly inhibiting the enzymatic activity of myosin, the fundamental motor of the sarcomere. This review summarizes the mechanism and translational progress of mavacamten from proteins to patients, describing how the mechanism of action and pharmacological characteristics, involving both systolic and diastolic effects, can directly target pathophysiological derangements within the cardiac sarcomere to improve cardiac structure and function in HCM. Mavacamten was approved by the Food and Drug Administration in April 2022 for the treatment of obstructive HCM and now goes by the commercial name of Camzyos. Full information about the risks, limitations, and side effects can be found at www.accessdata.fda.gov/drugsatfda_docs/label/2022/214998s000lbl.pdf.
Collapse
Affiliation(s)
- Suman Nag
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Sampath K Gollapudi
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Carlos L Del Rio
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
- Cardiac Consulting, 1630 S Delaware St. #56426, San Mateo, CA 94403, USA
| | | | - Robert McDowell
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| |
Collapse
|
10
|
Robinson P, Sparrow AJ, Psaras Y, Steeples V, Simon JN, Broyles CN, Chang YF, Brook FA, Wang YJ, Blease A, Zhang X, Abassi YA, Geeves MA, Toepfer CN, Watkins H, Redwood C, Daniels MJ. Comparing the effects of chemical Ca 2+ dyes and R-GECO on contractility and Ca 2+ transients in adult and human iPSC cardiomyocytes. J Mol Cell Cardiol 2023; 180:44-57. [PMID: 37127261 PMCID: PMC10659987 DOI: 10.1016/j.yjmcc.2023.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/13/2023] [Accepted: 04/28/2023] [Indexed: 05/03/2023]
Abstract
We compared commonly used BAPTA-derived chemical Ca2+ dyes (fura2, Fluo-4, and Rhod-2) with a newer genetically encoded indicator (R-GECO) in single cell models of the heart. We assessed their performance and effects on cardiomyocyte contractility, determining fluorescent signal-to-noise ratios and sarcomere shortening in primary ventricular myocytes from adult mouse and guinea pig, and in human iPSC-derived cardiomyocytes. Chemical Ca2+ dyes displayed dose-dependent contractile impairment in all cell types, and we observed a negative correlation between contraction and fluorescence signal-to-noise ratio, particularly for fura2 and Fluo-4. R-GECO had no effect on sarcomere shortening. BAPTA-based dyes, but not R-GECO, inhibited in vitro acto-myosin ATPase activity. The presence of fura2 accentuated or diminished changes in contractility and Ca2+ handling caused by small molecule modulators of contractility and intracellular ionic homeostasis (mavacamten, levosimendan, and flecainide), but this was not observed when using R-GECO in adult guinea pig left ventricular cardiomyocytes. Ca2+ handling studies are necessary for cardiotoxicity assessments of small molecules intended for clinical use. Caution should be exercised when interpreting small molecule studies assessing contractile effects and Ca2+ transients derived from BAPTA-like chemical Ca2+ dyes in cellular assays, a common platform for cardiac toxicology testing and mechanistic investigation of cardiac disease physiology and treatment.
Collapse
Affiliation(s)
- Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK.
| | - Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Yiangos Psaras
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Jillian N Simon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Connor N Broyles
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Yu-Fen Chang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Frances A Brook
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Ying-Jie Wang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Andrew Blease
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Xiaoyu Zhang
- Agilent Biosciences, Inc., San Diego, CA 92121, USA
| | | | | | - Christopher N Toepfer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Cardiology, Oxford University NHS Hospitals Trust, Oxford, UK
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Matthew J Daniels
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Cardiology, Oxford University NHS Hospitals Trust, Oxford, UK; Department of Cardiovascular Sciences, University of Manchester, Manchester, UK.
| |
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Mechanism based therapies enable personalised treatment of hypertrophic cardiomyopathy. Sci Rep 2022; 12:22501. [PMID: 36577774 PMCID: PMC9797561 DOI: 10.1038/s41598-022-26889-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 12/21/2022] [Indexed: 12/29/2022] Open
Abstract
Cardiomyopathies have unresolved genotype-phenotype relationships and lack disease-specific treatments. Here we provide a framework to identify genotype-specific pathomechanisms and therapeutic targets to accelerate the development of precision medicine. We use human cardiac electromechanical in-silico modelling and simulation which we validate with experimental hiPSC-CM data and modelling in combination with clinical biomarkers. We select hypertrophic cardiomyopathy as a challenge for this approach and study genetic variations that mutate proteins of the thick (MYH7R403Q/+) and thin filaments (TNNT2R92Q/+, TNNI3R21C/+) of the cardiac sarcomere. Using in-silico techniques we show that the destabilisation of myosin super relaxation observed in hiPSC-CMs drives disease in virtual cells and ventricles carrying the MYH7R403Q/+ variant, and that secondary effects on thin filament activation are necessary to precipitate slowed relaxation of the cell and diastolic insufficiency in the chamber. In-silico modelling shows that Mavacamten corrects the MYH7R403Q/+ phenotype in agreement with hiPSC-CM experiments. Our in-silico model predicts that the thin filament variants TNNT2R92Q/+ and TNNI3R21C/+ display altered calcium regulation as central pathomechanism, for which Mavacamten provides incomplete salvage, which we have corroborated in TNNT2R92Q/+ and TNNI3R21C/+ hiPSC-CMs. We define the ideal characteristics of a novel thin filament-targeting compound and show its efficacy in-silico. We demonstrate that hybrid human-based hiPSC-CM and in-silico studies accelerate pathomechanism discovery and classification testing, improving clinical interpretation of genetic variants, and directing rational therapeutic targeting and design.
Collapse
|
13
|
Martin AA, Thompson BR, Davis JP, Vang H, Hahn D, Metzger JM. Sarcomere dynamics revealed by a myofilament integrated FRET-based biosensor in live skeletal muscle fibers. Sci Rep 2022; 12:18116. [PMID: 36302792 PMCID: PMC9613882 DOI: 10.1038/s41598-022-21425-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 09/27/2022] [Indexed: 12/30/2022] Open
Abstract
The sarcomere is the functional unit of skeletal muscle, essential for proper contraction. Numerous acquired and inherited myopathies impact sarcomere function causing clinically significant disease. Mechanistic investigations of sarcomere activation have been challenging to undertake in the context of intact, live skeletal muscle fibers during real time physiological twitch contractions. Here, a skeletal muscle specific, intramolecular FRET-based biosensor was designed and engineered into fast skeletal muscle troponin C (TnC) to investigate the dynamics of sarcomere activation. In transgenic animals, the TnC biosensor incorporated into the skeletal muscle fiber sarcomeres by stoichiometric replacement of endogenous TnC and did not alter normal skeletal muscle contractile form or function. In intact single adult skeletal muscle fibers, real time twitch contractile data showed the TnC biosensor transient preceding the peak amplitude of contraction. Importantly, under physiological temperatures, inactivation of the TnC biosensor transient decayed significantly more slowly than the Ca2+ transient and contraction. The uncoupling of the TnC biosensor transient from the Ca2+ transient indicates the biosensor is not functioning as a Ca2+ transient reporter, but rather reports dynamic sarcomere activation/ inactivation that, in turn, is due to the ensemble effects of multiple activating ligands within the myofilaments. Together, these findings provide the foundation for implementing this new biosensor in future physiological studies investigating the mechanism of activation of the skeletal muscle sarcomere in health and disease.
Collapse
Affiliation(s)
- Ashley A Martin
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Brian R Thompson
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Jonathan P Davis
- Department of Physiology and Cell Biology, Ohio State University, Columbus, OH, USA
| | - Hluechy Vang
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Dongwoo Hahn
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Joseph M Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
| |
Collapse
|
14
|
Dowrick JM, Tran K, Garrett AS, Anderson AJ, Nielsen PMF, Taberner AJ, Han JC. Work-loop contractions reveal that the afterload-dependent time course of cardiac Ca 2+ transients is modulated by preload. J Appl Physiol (1985) 2022; 133:663-675. [PMID: 35771221 PMCID: PMC9762964 DOI: 10.1152/japplphysiol.00137.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Preload and afterload dictate the dynamics of the cyclical work-loop contraction that the heart undergoes in vivo. Cellular Ca2+ dynamics drive contraction, but the effects of afterload alone on the Ca2+ transient are inconclusive. To our knowledge, no study has investigated whether the putative afterload dependence of the Ca2+ transient is preload dependent. This study is designed to provide the first insight into the Ca2+ handling of cardiac trabeculae undergoing work-loop contractions, with the aim to examine whether the conflicting afterload dependency of the Ca2+ transient can be accounted for by considering preload under isometric and physiological work-loop contractions. Thus, we subjected ex vivo rat right-ventricular trabeculae, loaded with the fluorescent dye Fura-2, to work-loop contractions over a wide range of afterloads at two preloads while measuring stress, length changes, and Ca2+ transients. Work-loop control was implemented with a real-time Windkessel model to mimic the contraction patterns of the heart in vivo. We extracted a range of metrics from the measured steady-state twitch stress and Ca2+ transients, including the amplitudes, time courses, rates of rise, and integrals. Results show that parameters of stress were afterload and preload dependent. In contrast, the parameters associated with Ca2+ transients displayed a mixed dependence on afterload and preload. Most notably, its time course was afterload dependent, an effect augmented at the greater preload. This study reveals that the afterload dependence of cardiac Ca2+ transients is modulated by preload, which brings the study of Ca2+ transients during isometric contractions into question when aiming to understand physiological Ca2+ handling.NEW & NOTEWORTHY This study is the first examination of Ca2+ handling in trabeculae undergoing work-loop contractions. These data reveal that reducing preload diminishes the influence of afterload on the decay phase of the cardiac Ca2+ transient. This is significant as it reconciles inconsistencies in the literature regarding the influence of external loads on cardiac Ca2+ handling. Furthermore, these findings highlight discrepancies between Ca2+ handling during isometric and work-loop contractions in cardiac trabeculae operating at their optimal length.
Collapse
Affiliation(s)
- Jarrah M. Dowrick
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Kenneth Tran
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Amy S. Garrett
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Alex J. Anderson
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| | - Poul M. F. Nielsen
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,2Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - Andrew J. Taberner
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand,2Department of Engineering Science, University of Auckland, Auckland, New Zealand
| | - June-Chiew Han
- 1Auckland Bioengineering Institute, University of Auckland, Auckland, New Zealand
| |
Collapse
|
15
|
Halas M, Langa P, Warren CM, Goldspink PH, Wolska BM, Solaro RJ. Effects of Sarcomere Activators and Inhibitors Targeting Myosin Cross-Bridges on Ca2+-Activation of Mature and Immature Mouse Cardiac Myofilaments. Mol Pharmacol 2022; 101:286-299. [PMID: 35236770 PMCID: PMC9092471 DOI: 10.1124/molpharm.121.000420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 02/16/2022] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that isoform shifts in sarcomeres of the immature heart modify the effect of cardiac myosin-directed sarcomere inhibitors and activators. Omecamtiv mecarbil (OM) activates tension and is in clinical trials for the treatment of adult acute and chronic heart failure. Mavacamten (Mava) inhibits tension and is in clinical trials to relieve hyper-contractility and outflow obstruction in advanced genetic hypertrophic cardiomyopathy (HCM) linked commonly to mutations in sarcomeric proteins. To address the effect of these agents in developing sarcomeres we isolated heart fiber bundles, extracted membranes with Triton X-100, and measured tension developed over a range of Ca2+ concentrations with and without OM or Mava treatment. We made measurements in fiber bundles from hearts of adult non-transgenic controls (NTG) expressing cardiac troponin I (cTnI), and from hearts of transgenic mice (TG-ssTnI) expressing the fetal/neonatal form, slow skeletal troponin I (ssTnI). We also compared fibers from 7+14-day-old NTG mice expressing ssTnI and cTnI. These studies were repeated with 7+14-day old transgenic mice (TG-cTnT-R92Q) expressing a mutant form of cardiac TnT (cTnT) linked to HCM. OM increased Ca2+-sensitivity and decreased cooperative activation in both ssTnI- and cTnI- regulated myofilaments with a similar effect reducing sub-maximal tension in immature and mature myofilaments. Although Mava decreased tension similarly in cTnI- and ssTnI-regulated myofilaments controlled either by cTnT or cTnT-R92Q, its effect involved a depressed Ca2+-sensitivity in the mature cTnT-R92-myofilaments. Our data demonstrate an influence of myosin and thin filament-associated proteins on the actions of myosin-directed agents such as OM and Mava. Significance Statement The effects of myosin-targeted activators and inhibitors on Ca2+-activated tension in developing cardiac sarcomeres presented here provide novel, ex-vivo evidence as to their actions in early-stage cardiac disorders. These studies advance understanding of the molecular mechanisms of these agents that is important in pre-clinical studies employing sarcomere Ca2+-response as a screening approach. The data also inform the use of commonly immature cardiac myocytes generated from human inducible pluripotent stem cells in screening for sarcomere activators and inhibitors.
Collapse
Affiliation(s)
- Monika Halas
- Physiology and Biophysics, University of Illinois at Chicago, United States
| | - Paulina Langa
- Physiology and Biophysics, University of Illinois at Chicago, United States
| | - Chad M Warren
- Physiology and Biophysics, University of Illinois at Chicago, United States
| | - Paul H Goldspink
- Physiology and Biophysics, University of Illinois at Chicago, United States
| | - Beata M Wolska
- Department of Medicine, University of Illinois at Chicago, United States
| | - R John Solaro
- Physiology and Biophysics, University of Illinois at Chicago, United States
| |
Collapse
|
16
|
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.
Collapse
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
| |
Collapse
|
17
|
Bourque K, Hawey C, Jiang A, Mazarura GR, Hébert TE. Biosensor-based profiling to track cellular signalling in patient-derived models of dilated cardiomyopathy. Cell Signal 2022; 91:110239. [PMID: 34990783 DOI: 10.1016/j.cellsig.2021.110239] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/06/2021] [Accepted: 12/29/2021] [Indexed: 12/18/2022]
Abstract
Dilated cardiomyopathies (DCM) represent a diverse group of cardiovascular diseases impacting the structure and function of the myocardium. To better treat these diseases, we need to understand the impact of such cardiomyopathies on critical signalling pathways that drive disease progression downstream of receptors we often target therapeutically. Our understanding of cellular signalling events has progressed substantially in the last few years, in large part due to the design, validation and use of biosensor-based approaches to studying such events in cells, tissues and in some cases, living animals. Another transformative development has been the use of human induced pluripotent stem cells (hiPSCs) to generate disease-relevant models from individual patients. We highlight the importance of going beyond monocellular cultures to incorporate the influence of paracrine signalling mediators. Finally, we discuss the recent coalition of these approaches in the context of DCM. We discuss recent work in generating patient-derived models of cardiomyopathies and the utility of using signalling biosensors to track disease progression and test potential therapeutic strategies that can be later used to inform treatment options in patients.
Collapse
Affiliation(s)
- Kyla Bourque
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Cara Hawey
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Alyson Jiang
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Grace R Mazarura
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3G 1Y6, Canada.
| |
Collapse
|
18
|
Daniels MJ, Fusi L, Semsarian C, Naidu SS. Myosin Modulation in Hypertrophic Cardiomyopathy and Systolic Heart Failure: Getting Inside the Engine. Circulation 2021; 144:759-762. [PMID: 34491773 PMCID: PMC7611636 DOI: 10.1161/circulationaha.121.056324] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Affiliation(s)
- Matthew J Daniels
- Manchester Heart Centre, Manchester Royal Infirmary, Manchester University NHS Foundation Trust, United Kingdom (M.J.D.).,Division of Cardiovascular Sciences, Manchester Academic Health Sciences Center (M.J.D.), University of Manchester, Manchester, United Kingdom.,Division of Cell Matrix Biology and Regenerative Medicine (M.J.D.), University of Manchester, Manchester, United Kingdom
| | - Luca Fusi
- Randall Center for Cell and Molecular Biophysics and BHF Center for Research Excellence, King's College London, United Kingdom (L.F.)
| | - Christopher Semsarian
- Agnes Ginges Centre for Molecular Cardiology at Centenary Institute, The University of Sydney, Australia (C.S.)
| | - Srihari S Naidu
- Hypertrophic Cardiomyopathy Center, Department of Cardiology, Westchester Medical Center, Valhalla, NY (S.S.N.)
| |
Collapse
|
19
|
Psaras Y, Margara F, Cicconet M, Sparrow AJ, Repetti GG, Schmid M, Steeples V, Wilcox JA, Bueno-Orovio A, Redwood CS, Watkins HC, Robinson P, Rodriguez B, Seidman JG, Seidman CE, Toepfer CN. CalTrack: High-Throughput Automated Calcium Transient Analysis in Cardiomyocytes. Circ Res 2021; 129:326-341. [PMID: 34018815 PMCID: PMC8260473 DOI: 10.1161/circresaha.121.318868] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/06/2021] [Accepted: 05/20/2021] [Indexed: 11/21/2022]
Abstract
[Figure: see text].
Collapse
Affiliation(s)
- Yiangos Psaras
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
| | - Francesca Margara
- Computer Science (F.M., A.B.-O., B.R.), University of Oxford, United Kingdom
| | - Marcelo Cicconet
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
- Computer Science (F.M., A.B.-O., B.R.), University of Oxford, United Kingdom
- Wellcome Centre for Human Genetics (H.C.W., C.N.T.), University of Oxford, United Kingdom
- Image and Data Analysis Core (M.C.), Harvard Medical School, Boston, MA
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA (C.E.S.)
- Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.)
| | - Alexander J. Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
- Computer Science (F.M., A.B.-O., B.R.), University of Oxford, United Kingdom
- Wellcome Centre for Human Genetics (H.C.W., C.N.T.), University of Oxford, United Kingdom
- Image and Data Analysis Core (M.C.), Harvard Medical School, Boston, MA
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA (C.E.S.)
- Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.)
| | - Giuliana G. Repetti
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
| | - Manuel Schmid
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
- Computer Science (F.M., A.B.-O., B.R.), University of Oxford, United Kingdom
- Wellcome Centre for Human Genetics (H.C.W., C.N.T.), University of Oxford, United Kingdom
- Image and Data Analysis Core (M.C.), Harvard Medical School, Boston, MA
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA (C.E.S.)
- Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.)
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
- Computer Science (F.M., A.B.-O., B.R.), University of Oxford, United Kingdom
- Wellcome Centre for Human Genetics (H.C.W., C.N.T.), University of Oxford, United Kingdom
- Image and Data Analysis Core (M.C.), Harvard Medical School, Boston, MA
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA (C.E.S.)
- Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.)
| | - Jonathan A.L. Wilcox
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
| | | | - Charles S. Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
- Computer Science (F.M., A.B.-O., B.R.), University of Oxford, United Kingdom
- Wellcome Centre for Human Genetics (H.C.W., C.N.T.), University of Oxford, United Kingdom
- Image and Data Analysis Core (M.C.), Harvard Medical School, Boston, MA
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA (C.E.S.)
- Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.)
| | - Hugh C. Watkins
- Wellcome Centre for Human Genetics (H.C.W., C.N.T.), University of Oxford, United Kingdom
| | - Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
| | - Blanca Rodriguez
- Computer Science (F.M., A.B.-O., B.R.), University of Oxford, United Kingdom
| | - Jonathan G. Seidman
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
| | - Christine E. Seidman
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
- Cardiovascular Division, Department of Medicine, Brigham and Women’s Hospital, Boston, MA (C.E.S.)
- Howard Hughes Medical Institute, Chevy Chase, MD (C.E.S.)
| | - Christopher N. Toepfer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine (Y.P., F.M., A.J.S., M.S., V.S., C.S.R., H.C.W., P.R., C.N.T.), University of Oxford, United Kingdom
- Wellcome Centre for Human Genetics (H.C.W., C.N.T.), University of Oxford, United Kingdom
- Genetics (G.G.R., J.A.L.W., J.G.S., C.E.S., C.N.T.), Harvard Medical School, Boston, MA
| |
Collapse
|
20
|
Iorga B, Kraft T. Why make a strong muscle weaker? J Gen Physiol 2021; 153:212267. [PMID: 34106212 PMCID: PMC8193566 DOI: 10.1085/jgp.202112928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Bogdan Iorga
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany.,Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Theresia Kraft
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| |
Collapse
|
21
|
Pettinato AM, Yoo D, VanOudenhove J, Chen YS, Cohn R, Ladha FA, Yang X, Thakar K, Romano R, Legere N, Meredith E, Robson P, Regnier M, Cotney JL, Murry CE, Hinson JT. Sarcomere function activates a p53-dependent DNA damage response that promotes polyploidization and limits in vivo cell engraftment. Cell Rep 2021; 35:109088. [PMID: 33951429 PMCID: PMC8161465 DOI: 10.1016/j.celrep.2021.109088] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 03/11/2021] [Accepted: 04/14/2021] [Indexed: 12/21/2022] Open
Abstract
Human cardiac regeneration is limited by low cardiomyocyte replicative rates and progressive polyploidization by unclear mechanisms. To study this process, we engineer a human cardiomyocyte model to track replication and polyploidization using fluorescently tagged cyclin B1 and cardiac troponin T. Using time-lapse imaging, in vitro cardiomyocyte replication patterns recapitulate the progressive mononuclear polyploidization and replicative arrest observed in vivo. Single-cell transcriptomics and chromatin state analyses reveal that polyploidization is preceded by sarcomere assembly, enhanced oxidative metabolism, a DNA damage response, and p53 activation. CRISPR knockout screening reveals p53 as a driver of cell-cycle arrest and polyploidization. Inhibiting sarcomere function, or scavenging ROS, inhibits cell-cycle arrest and polyploidization. Finally, we show that cardiomyocyte engraftment in infarcted rat hearts is enhanced 4-fold by the increased proliferation of troponin-knockout cardiomyocytes. Thus, the sarcomere inhibits cell division through a DNA damage response that can be targeted to improve cardiomyocyte replacement strategies.
Collapse
Affiliation(s)
- Anthony M Pettinato
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT 06030, USA
| | - Dasom Yoo
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA
| | | | - Yu-Sheng Chen
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Rachel Cohn
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Feria A Ladha
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT 06030, USA
| | - Xiulan Yang
- Center for Cardiovascular Biology and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA
| | - Ketan Thakar
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Robert Romano
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Nicolas Legere
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Emily Meredith
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Paul Robson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Michael Regnier
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA
| | - Justin L Cotney
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT 06030, USA
| | - Charles E Murry
- Department of Bioengineering, University of Washington, Seattle, WA 98109, USA; Center for Cardiovascular Biology and Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, WA 98109, USA; Department of Pathology, University of Washington, Seattle, WA 98109, USA; Department of Medicine/Cardiology, University of Washington, Seattle, WA 98109, USA
| | - J Travis Hinson
- Department of Genetics and Genome Sciences, UConn Health, Farmington, CT 06030, USA; The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA.
| |
Collapse
|
22
|
Image entropy-based label-free functional characterization of human induced pluripotent stem cell-derived 3D cardiac spheroids. Biosens Bioelectron 2021; 179:113055. [PMID: 33582565 DOI: 10.1016/j.bios.2021.113055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 01/25/2021] [Accepted: 01/27/2021] [Indexed: 11/22/2022]
Abstract
Human induced pluripotent stem cell-derived cardiac spheroids (iPSC-CSs) in 3D possess tremendous potential for treating heart diseases and screening drugs for their cardiac effect. The beating pattern (including beating frequency and amplitude) of iPSC-CSs is a direct indicator of their health and function. However, detecting the beating pattern of 3D cardiac spheroid is not well studied and the probes commonly used for labeling cardiomyocytes for their beating pattern detection is toxic during long-term culture. Here, we reveal that the beating pattern of 3D iPSC-CSs can be conveniently detected/quantified by calculating the relative change of entropy in all the frames/images of non-fluorescent optical signal without labeling any cells. The entropy rate superpixel segmentation method is used for image segmentation in frames containing multiple or aggregated iPSC-CSs to identify individual iPSC-CSs, enabling rapid detection/quantification of the beating pattern of each iPSC-CS. Moreover, the responses of iPSC-CSs to both anticancer and cardiac drugs can be reliably detected with the image entropy-based label-free method in terms of their beating patterns. This novel label-free approach may be valuable for convenient and efficient functional evaluation of 3D and 2D cardiac constructs, which is important not only for drug screening but also the advancement of manufacturing functional cardiac constructs to treat heart diseases.
Collapse
|
23
|
Scellini B, Piroddi N, Dente M, Vitale G, Pioner JM, Coppini R, Ferrantini C, Poggesi C, Tesi C. Mavacamten has a differential impact on force generation in myofibrils from rabbit psoas and human cardiac muscle. J Gen Physiol 2021; 153:212024. [PMID: 33891673 PMCID: PMC8077167 DOI: 10.1085/jgp.202012789] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 03/04/2021] [Accepted: 03/30/2021] [Indexed: 12/20/2022] Open
Abstract
Mavacamten (MYK-461) is a small-molecule allosteric inhibitor of sarcomeric myosins being used in preclinical/clinical trials for hypertrophic cardiomyopathy treatment. A better understanding of its impact on force generation in intact or skinned striated muscle preparations, especially for human cardiac muscle, has been hindered by diffusional barriers. These limitations have been overcome by mechanical experiments using myofibrils subject to perturbations of the contractile environment by sudden solution changes. Here, we characterize the action of mavacamten in human ventricular myofibrils compared with fast skeletal myofibrils from rabbit psoas. Mavacamten had a fast, fully reversible, and dose-dependent negative effect on maximal Ca2+-activated isometric force at 15°C, which can be explained by a sudden decrease in the number of heads functionally available for interaction with actin. It also decreased the kinetics of force development in fast skeletal myofibrils, while it had no effect in human ventricular myofibrils. For both myofibril types, the effects of mavacamten were independent from phosphate in the low-concentration range. Mavacamten did not alter force relaxation of fast skeletal myofibrils, but it significantly accelerated the relaxation of human ventricular myofibrils. Lastly, mavacamten had no effect on resting tension but inhibited the ADP-stimulated force in the absence of Ca2+. Altogether, these effects outline a motor isoform-specific dependence of the inhibitory effect of mavacamten on force generation, which is mediated by a reduction in the availability of strongly actin-binding heads. Mavacamten may thus alter the interplay between thick and thin filament regulation mechanisms of contraction in association with the widely documented drug effect of stabilizing myosin motor heads into autoinhibited states.
Collapse
Affiliation(s)
- Beatrice Scellini
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Nicoletta Piroddi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Marica Dente
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Giulia Vitale
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Josè Manuel Pioner
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Raffaele Coppini
- Department of Neuroscience, Psychology, Drug Sciences, and Child Health, University of Florence, Florence, Italy
| | - Cecilia Ferrantini
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Corrado Poggesi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| | - Chiara Tesi
- Department of Experimental and Clinical Medicine, Division of Physiology, University of Florence, Florence, Italy
| |
Collapse
|
24
|
Solís C, Solaro RJ. Novel insights into sarcomere regulatory systems control of cardiac thin filament activation. J Gen Physiol 2021; 153:211903. [PMID: 33740037 PMCID: PMC7988513 DOI: 10.1085/jgp.202012777] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 02/23/2021] [Indexed: 12/11/2022] Open
Abstract
Our review focuses on sarcomere regulatory mechanisms with a discussion of cardiac-specific modifications to the three-state model of thin filament activation from a blocked to closed to open state. We discuss modulation of these thin filament transitions by Ca2+, by crossbridge interactions, and by thick filament–associated proteins, cardiac myosin–binding protein C (cMyBP-C), cardiac regulatory light chain (cRLC), and titin. Emerging evidence supports the idea that the cooperative activation of the thin filaments despite a single Ca2+ triggering regulatory site on troponin C (cTnC) cannot be considered in isolation of other functional domains of the sarcomere. We discuss long- and short-range interactions among these domains with the regulatory units of thin filaments, including proteins at the barbed end at the Z-disc and the pointed end near the M-band. Important to these discussions is the ever-increasing understanding of the role of cMyBP-C, cRLC, and titin filaments. Detailed knowledge of these control processes is critical to the understanding of mechanisms sustaining physiological cardiac state with varying hemodynamic load, to better defining genetic and acquired cardiac disorders, and to developing targets for therapies at the level of the sarcomeres.
Collapse
Affiliation(s)
- Christopher Solís
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
| | - R John Solaro
- University of Illinois at Chicago, College of Medicine, Department of Physiology and Biophysics and Center for Cardiovascular Research, Chicago, IL
| |
Collapse
|
25
|
Jiang H, Hooper C, Kelly M, Steeples V, Simon JN, Beglov J, Azad AJ, Leinhos L, Bennett P, Ehler E, Kalisch-Smith JI, Sparrow DB, Fischer R, Heilig R, Isackson H, Ehsan M, Patone G, Huebner N, Davies B, Watkins H, Gehmlich K. Functional analysis of a gene-edited mouse model to gain insights into the disease mechanisms of a titin missense variant. Basic Res Cardiol 2021; 116:14. [PMID: 33637999 PMCID: PMC7910237 DOI: 10.1007/s00395-021-00853-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 02/10/2021] [Indexed: 11/03/2022]
Abstract
Titin truncating variants are a well-established cause of cardiomyopathy; however, the role of titin missense variants is less well understood. Here we describe the generation of a mouse model to investigate the underlying disease mechanism of a previously reported titin A178D missense variant identified in a family with non-compaction and dilated cardiomyopathy. Heterozygous and homozygous mice carrying the titin A178D missense variant were characterised in vivo by echocardiography. Heterozygous mice had no detectable phenotype at any time point investigated (up to 1 year). By contrast, homozygous mice developed dilated cardiomyopathy from 3 months. Chronic adrenergic stimulation aggravated the phenotype. Targeted transcript profiling revealed induction of the foetal gene programme and hypertrophic signalling pathways in homozygous mice, and these were confirmed at the protein level. Unsupervised proteomics identified downregulation of telethonin and four-and-a-half LIM domain 2, as well as the upregulation of heat shock proteins and myeloid leukaemia factor 1. Loss of telethonin from the cardiac Z-disc was accompanied by proteasomal degradation; however, unfolded telethonin accumulated in the cytoplasm, leading to a proteo-toxic response in the mice.We show that the titin A178D missense variant is pathogenic in homozygous mice, resulting in cardiomyopathy. We also provide evidence of the disease mechanism: because the titin A178D variant abolishes binding of telethonin, this leads to its abnormal cytoplasmic accumulation. Subsequent degradation of telethonin by the proteasome results in proteasomal overload, and activation of a proteo-toxic response. The latter appears to be a driving factor for the cardiomyopathy observed in the mouse model.
Collapse
Affiliation(s)
- He Jiang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Charlotte Hooper
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Matthew Kelly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Jillian N Simon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Julia Beglov
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Amar J Azad
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Lisa Leinhos
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Pauline Bennett
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King's College London BHF Centre of Research Excellence, London, UK
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King's College London BHF Centre of Research Excellence, London, UK
| | | | - Duncan B Sparrow
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Roman Fischer
- Nuffield Department of Clinical Medicine, Target Discovery Institute, University of Oxford, Oxford, UK
| | - Raphael Heilig
- Nuffield Department of Clinical Medicine, Target Discovery Institute, University of Oxford, Oxford, UK
| | - Henrik Isackson
- Department of Medical Sciences, Cardiology, Uppsala University, Uppsala, Sweden
- Department of Medical Cell Biology, Integrative Physiology, Uppsala University, Uppsala, Sweden
| | - Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Giannino Patone
- Max Delbrueck Centre for Molecular Medicine, Berlin, Germany
| | - Norbert Huebner
- Max Delbrueck Centre for Molecular Medicine, Berlin, Germany
| | - Benjamin Davies
- Transgenic Core, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence Oxford, University of Oxford, Oxford, OX3 9DU, UK.
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham, B15 2TT, UK.
| |
Collapse
|
26
|
Awinda PO, Watanabe M, Bishaw Y, Huckabee AM, Agonias KB, Kazmierczak K, Szczesna-Cordary D, Tanner BCW. Mavacamten decreases maximal force and Ca 2+ sensitivity in the N47K-myosin regulatory light chain mouse model of hypertrophic cardiomyopathy. Am J Physiol Heart Circ Physiol 2021; 320:H881-H890. [PMID: 33337957 PMCID: PMC8082789 DOI: 10.1152/ajpheart.00345.2020] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 12/10/2020] [Accepted: 12/10/2020] [Indexed: 01/12/2023]
Abstract
Morbidity and mortality associated with heart disease is a growing threat to the global population, and novel therapies are needed. Mavacamten (formerly called MYK-461) is a small molecule that binds to cardiac myosin and inhibits myosin ATPase. Mavacamten is currently in clinical trials for the treatment of obstructive hypertrophic cardiomyopathy (HCM), and it may provide benefits for treating other forms of heart disease. We investigated the effect of mavacamten on cardiac muscle contraction in two transgenic mouse lines expressing the human isoform of cardiac myosin regulatory light chain (RLC) in their hearts. Control mice expressed wild-type RLC (WT-RLC), and HCM mice expressed the N47K RLC mutation. In the absence of mavacamten, skinned papillary muscle strips from WT-RLC mice produced greater isometric force than strips from N47K mice. Adding 0.3 µM mavacamten decreased maximal isometric force and reduced Ca2+ sensitivity of contraction for both genotypes, but this reduction in pCa50 was nearly twice as large for WT-RLC versus N47K. We also used stochastic length-perturbation analysis to characterize cross-bridge kinetics. The cross-bridge detachment rate was measured as a function of [MgATP] to determine the effect of mavacamten on myosin nucleotide handling rates. Mavacamten increased the MgADP release and MgATP binding rates for both genotypes, thereby contributing to faster cross-bridge detachment, which could speed up myocardial relaxation during diastole. Our data suggest that mavacamten reduces isometric tension and Ca2+ sensitivity of contraction via decreased strong cross-bridge binding. Mavacamten may become a useful therapy for patients with heart disease, including some forms of HCM.NEW & NOTEWORTHY Mavacamten is a pharmaceutical that binds to myosin, and it is under investigation as a therapy for some forms of heart disease. We show that mavacamten reduces isometric tension and Ca2+ sensitivity of contraction in skinned myocardial strips from a mouse model of hypertrophic cardiomyopathy that expresses the N47K mutation in cardiac myosin regulatory light chain. Mavacamten reduces contractility by decreasing strong cross-bridge binding, partially due to faster cross-bridge nucleotide handling rates that speed up myosin detachment.
Collapse
Affiliation(s)
- Peter O Awinda
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Marissa Watanabe
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Yemeserach Bishaw
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Anna M Huckabee
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Keinan B Agonias
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Katarzyna Kazmierczak
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida
| | - Danuta Szczesna-Cordary
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida
| | - Bertrand C W Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| |
Collapse
|
27
|
Genetic Restrictive Cardiomyopathy: Causes and Consequences-An Integrative Approach. Int J Mol Sci 2021; 22:ijms22020558. [PMID: 33429969 PMCID: PMC7827163 DOI: 10.3390/ijms22020558] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/05/2021] [Accepted: 01/06/2021] [Indexed: 12/12/2022] Open
Abstract
The sarcomere as the smallest contractile unit is prone to alterations in its functional, structural and associated proteins. Sarcomeric dysfunction leads to heart failure or cardiomyopathies like hypertrophic (HCM) or restrictive cardiomyopathy (RCM) etc. Genetic based RCM, a very rare but severe disease with a high mortality rate, might be induced by mutations in genes of non-sarcomeric, sarcomeric and sarcomere associated proteins. In this review, we discuss the functional effects in correlation to the phenotype and present an integrated model for the development of genetic RCM.
Collapse
|
28
|
Awinda PO, Bishaw Y, Watanabe M, Guglin MA, Campbell KS, Tanner BCW. Effects of mavacamten on Ca 2+ sensitivity of contraction as sarcomere length varied in human myocardium. Br J Pharmacol 2020; 177:5609-5621. [PMID: 32960449 PMCID: PMC7707091 DOI: 10.1111/bph.15271] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 09/08/2020] [Accepted: 09/11/2020] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND PURPOSE Heart failure can reflect impaired contractile function at the myofilament level. In healthy hearts, myofilaments become more sensitive to Ca2+ as cells are stretched. This represents a fundamental property of the myocardium that contributes to the Frank-Starling response, although the molecular mechanisms underlying the effect remain unclear. Mavacamten, which binds to myosin, is under investigation as a potential therapy for heart disease. We investigated how mavacamten affects the sarcomere-length dependence of Ca2+ -sensitive isometric contraction to determine how mavacamten might modulate the Frank-Starling mechanism. EXPERIMENTAL APPROACH Multicellular preparations from the left ventricular-free wall of hearts from organ donors were chemically permeabilized and Ca2+ activated in the presence or absence of 0.5-μM mavacamten at 1.9 or 2.3-μm sarcomere length (37°C). Isometric force and frequency-dependent viscoelastic myocardial stiffness measurements were made. KEY RESULTS At both sarcomere lengths, mavacamten reduced maximal force and Ca2+ sensitivity of contraction. In the presence and absence of mavacamten, Ca2+ sensitivity of force increased as sarcomere length increased. This suggests that the length-dependent activation response was maintained in human myocardium, even though mavacamten reduced Ca2+ sensitivity. There were subtle effects of mavacamten reducing force values under relaxed conditions (pCa 8.0), as well as slowing myosin cross-bridge recruitment and speeding cross-bridge detachment under maximally activated conditions (pCa 4.5). CONCLUSION AND IMPLICATIONS Mavacamten did not eliminate sarcomere length-dependent increases in the Ca2+ sensitivity of contraction in myocardial strips from organ donors at physiological temperature. Drugs that modulate myofilament function may be useful therapies for cardiomyopathies.
Collapse
Affiliation(s)
- Peter O. Awinda
- Department of Integrative Physiology and NeuroscienceWashington State UniversityPullmanWashingtonUSA
| | - Yemeserach Bishaw
- Department of Integrative Physiology and NeuroscienceWashington State UniversityPullmanWashingtonUSA
| | - Marissa Watanabe
- Department of Integrative Physiology and NeuroscienceWashington State UniversityPullmanWashingtonUSA
| | - Maya A. Guglin
- Division of Cardiovascular MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Kenneth S. Campbell
- Department of PhysiologyUniversity of KentuckyLexingtonKentuckyUSA
- Division of Cardiovascular MedicineUniversity of KentuckyLexingtonKentuckyUSA
| | - Bertrand C. W. Tanner
- Department of Integrative Physiology and NeuroscienceWashington State UniversityPullmanWashingtonUSA
| |
Collapse
|
29
|
Pettinato AM, Ladha FA, Mellert DJ, Legere N, Cohn R, Romano R, Thakar K, Chen YS, Hinson JT. Development of a Cardiac Sarcomere Functional Genomics Platform to Enable Scalable Interrogation of Human TNNT2 Variants. Circulation 2020; 142:2262-2275. [PMID: 33025817 DOI: 10.1161/circulationaha.120.047999] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND Pathogenic TNNT2 variants are a cause of hypertrophic and dilated cardiomyopathies, which promote heart failure by incompletely understood mechanisms. The precise functional significance for 87% of TNNT2 variants remains undetermined, in part, because of a lack of functional genomics studies. The knowledge of which and how TNNT2 variants cause hypertrophic and dilated cardiomyopathies could improve heart failure risk determination, treatment efficacy, and therapeutic discovery, and provide new insights into cardiomyopathy pathogenesis, as well. METHODS We created a toolkit of human induced pluripotent stem cell models and functional assays using CRISPR/Cas9 to study TNNT2 variant pathogenicity and pathophysiology. Using human induced pluripotent stem cell-derived cardiomyocytes in cardiac microtissue and single-cell assays, we functionally interrogated 51 TNNT2 variants, including 30 pathogenic/likely pathogenic variants and 21 variants of uncertain significance. We used RNA sequencing to determine the transcriptomic consequences of pathogenic TNNT2 variants and adapted CRISPR/Cas9 to engineer a transcriptional reporter assay to assist prediction of TNNT2 variant pathogenicity. We also studied variant-specific pathophysiology using a thin filament-directed calcium reporter to monitor changes in myofilament calcium affinity. RESULTS Hypertrophic cardiomyopathy-associated TNNT2 variants caused increased cardiac microtissue contraction, whereas dilated cardiomyopathy-associated variants decreased contraction. TNNT2 variant-dependent changes in sarcomere contractile function induced graded regulation of 101 gene transcripts, including MAPK (mitogen-activated protein kinase) signaling targets, HOPX, and NPPB. We distinguished pathogenic TNNT2 variants from wildtype controls using a sarcomere functional reporter engineered by inserting tdTomato into the endogenous NPPB locus. On the basis of a combination of NPPB reporter activity and cardiac microtissue contraction, our study provides experimental support for the reclassification of 2 pathogenic/likely pathogenic variants and 2 variants of uncertain significance. CONCLUSIONS Our study found that hypertrophic cardiomyopathy-associated TNNT2 variants increased cardiac microtissue contraction, whereas dilated cardiomyopathy-associated variants decreased contraction, both of which paralleled changes in myofilament calcium affinity. Transcriptomic changes, including NPPB levels, directly correlated with sarcomere function and can be used to predict TNNT2 variant pathogenicity.
Collapse
Affiliation(s)
| | - Feria A Ladha
- University of Connecticut Health Center (A.M.P., F.A.L., R.R., J.T.H.)
| | - David J Mellert
- The Jackson Laboratory for Genomic Medicine (D.J.M., N.L., R.C., K.T., Y.-S.C., J.T.H.)
| | - Nicholas Legere
- The Jackson Laboratory for Genomic Medicine (D.J.M., N.L., R.C., K.T., Y.-S.C., J.T.H.)
| | - Rachel Cohn
- The Jackson Laboratory for Genomic Medicine (D.J.M., N.L., R.C., K.T., Y.-S.C., J.T.H.)
| | - Robert Romano
- University of Connecticut Health Center (A.M.P., F.A.L., R.R., J.T.H.)
| | - Ketan Thakar
- The Jackson Laboratory for Genomic Medicine (D.J.M., N.L., R.C., K.T., Y.-S.C., J.T.H.)
| | - Yu-Sheng Chen
- The Jackson Laboratory for Genomic Medicine (D.J.M., N.L., R.C., K.T., Y.-S.C., J.T.H.)
| | - J Travis Hinson
- University of Connecticut Health Center (A.M.P., F.A.L., R.R., J.T.H.).,The Jackson Laboratory for Genomic Medicine (D.J.M., N.L., R.C., K.T., Y.-S.C., J.T.H.).,Calhoun Cardiology Center, UConn Health (J.T.H.), Farmington
| |
Collapse
|
30
|
Ca 2+ Release via IP 3 Receptors Shapes the Cardiac Ca 2+ Transient for Hypertrophic Signaling. Biophys J 2020; 119:1178-1192. [PMID: 32871099 DOI: 10.1016/j.bpj.2020.08.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 06/16/2020] [Accepted: 08/04/2020] [Indexed: 12/27/2022] Open
Abstract
Calcium (Ca2+) plays a central role in mediating both contractile function and hypertrophic signaling in ventricular cardiomyocytes. L-type Ca2+ channels trigger release of Ca2+ from ryanodine receptors for cellular contraction, whereas signaling downstream of G-protein-coupled receptors stimulates Ca2+ release via inositol 1,4,5-trisphosphate receptors (IP3Rs), engaging hypertrophic signaling pathways. Modulation of the amplitude, duration, and duty cycle of the cytosolic Ca2+ contraction signal and spatial localization have all been proposed to encode this hypertrophic signal. Given current knowledge of IP3Rs, we develop a model describing the effect of functional interaction (cross talk) between ryanodine receptor and IP3R channels on the Ca2+ transient and examine the sensitivity of the Ca2+ transient shape to properties of IP3R activation. A key result of our study is that IP3R activation increases Ca2+ transient duration for a broad range of IP3R properties, but the effect of IP3R activation on Ca2+ transient amplitude is dependent on IP3 concentration. Furthermore we demonstrate that IP3-mediated Ca2+ release in the cytosol increases the duty cycle of the Ca2+ transient, the fraction of the cycle for which [Ca2+] is elevated, across a broad range of parameter values and IP3 concentrations. When coupled to a model of downstream transcription factor (NFAT) activation, we demonstrate that there is a high correspondence between the Ca2+ transient duty cycle and the proportion of activated NFAT in the nucleus. These findings suggest increased cytosolic Ca2+ duty cycle as a plausible mechanism for IP3-dependent hypertrophic signaling via Ca2+-sensitive transcription factors such as NFAT in ventricular cardiomyocytes.
Collapse
|
31
|
Sarcomere integrated biosensor detects myofilament-activating ligands in real time during twitch contractions in live cardiac muscle. J Mol Cell Cardiol 2020; 147:49-61. [PMID: 32791214 DOI: 10.1016/j.yjmcc.2020.07.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/14/2020] [Accepted: 07/30/2020] [Indexed: 11/24/2022]
Abstract
The sarcomere is the functional unit of cardiac muscle, essential for normal heart function. To date, it has not been possible to study, in real time, thin filament-based activation dynamics in live cardiac muscle. We report here results from a cardiac troponin C (TnC) FRET-based biosensor integrated into the cardiac sarcomere via stoichiometric replacement of endogenous TnC. The TnC biosensor provides, for the first time, evidence of multiple thin filament activating ligands, including troponin I interfacing with TnC and cycling myosin, during a cardiac twitch. Results show that the TnC FRET biosensor transient significantly precedes that of peak twitch force. Using small molecules and genetic modifiers known to alter sarcomere activation, independently of the intracellular Ca2+ transient, the data show that the TnC biosensor detects significant effects of the troponin I switch domain as a sarcomere-activating ligand. Interestingly, the TnC biosensor also detected the effects of load-dependent altered myosin cycling, as shown by a significant delay in TnC biosensor transient inactivation during the isometric twitch. In addition, the TnC biosensor detected the effects of myosin as an activating ligand during the twitch by using a small molecule that directly alters cross-bridge cycling, independently of the intracellular Ca2+ transient. Collectively, these results aid in illuminating the basis of cardiac muscle contractile activation with implications for gene, protein, and small molecule-based strategies designed to target the sarcomere in regulating beat-to-beat heart performance in health and disease.
Collapse
|
32
|
Lookin O. The use of Ca-transient to evaluate Ca 2+ utilization by myofilaments in living cardiac muscle. Clin Exp Pharmacol Physiol 2020; 47:1824-1833. [PMID: 32654202 DOI: 10.1111/1440-1681.13376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/15/2020] [Accepted: 07/08/2020] [Indexed: 12/20/2022]
Abstract
The kinetics of Ca2+ interaction with myofilaments is an important determinant of the preload-dependent effects on myocardial contractility (the Frank-Starling Mechanism). However, the direct evaluation of this interaction in intact tissue is limited. To overcome this issue, the method of difference curve was proposed, which implements the subtraction of the referent Ca-transient (measured in non-stretched muscle) from the Ca-transients measured at different preloads. This method was tested on the cardiac trabeculae of healthy (CONT) and monocrotaline-treated rats (MCT), subjected to force-length protocol with simultaneous measurement of isometric twitch and Ca-transient. The difference curve had two components, C2 and C3, which are distinct in their directions and, as hypothesized, may reflect mainly the kinetics of Ca2+ utilization by and release from myofilaments, respectively. Both the components were quantitatively evaluated by their amplitude, integral magnitude and time-to-peak. The C3 component in either CONT or MCT was significantly higher in its amplitude/integral magnitude vs the C2 component, at any preload (P < .05). The time-to-peak value was preload-dependent only for the C3 component. There were tight relationships between the above characteristics of C2/C3 components and the characteristics of isometric tension (peak value, time-to-peak and the maximal rates of rise/decline) in CONT and MCT muscles. The C3 component was highly consistent with tension relaxation (Ca2+ release from myofilaments), but the C2 component was partially consistent with tension development (Ca2+ utilization by myofilaments). The novel method of the analysis of Ca-transients can be utilized for indirect evaluation of Ca2+ interaction with myofilaments in healthy and diseased myocardium.
Collapse
Affiliation(s)
- Oleg Lookin
- Institute of Immunology and Physiology, Ural Branch of Russian Academy of Sciences, Yekaterinburg, Russian Federation.,The Center for Fundamental Biotechnology and Bioengineering, Institute of Natural Sciences and Mathematics, Ural Federal University, Yekaterinburg, Russian Federation
| |
Collapse
|
33
|
Bhagwan JR, Mosqueira D, Chairez-Cantu K, Mannhardt I, Bodbin SE, Bakar M, Smith JGW, Denning C. Isogenic models of hypertrophic cardiomyopathy unveil differential phenotypes and mechanism-driven therapeutics. J Mol Cell Cardiol 2020; 145:43-53. [PMID: 32531470 PMCID: PMC7487780 DOI: 10.1016/j.yjmcc.2020.06.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 05/18/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) is a prevalent and complex cardiovascular condition. Despite being strongly associated with genetic alterations, wide variation of disease penetrance, expressivity and hallmarks of progression complicate treatment. We aimed to characterize different human isogenic cellular models of HCM bearing patient-relevant mutations to clarify genetic causation and disease mechanisms, hence facilitating the development of effective therapeutics. METHODS We directly compared the p.β-MHC-R453C and p.ACTC1-E99K HCM-associated mutations in human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and their healthy isogenic counterparts, generated using CRISPR/Cas9 genome editing technology. By harnessing several state-of-the-art HCM phenotyping techniques, these mutations were investigated to identify similarities and differences in disease progression and hypertrophic signaling pathways, towards establishing potential targets for pharmacological treatment. CRISPR/Cas9 knock-in of the genetically-encoded calcium indicator R-GECO1.0 to the AAVS1 locus into these disease models resulted in calcium reporter lines. RESULTS Confocal line scan analysis identified calcium transient arrhythmias and intracellular calcium overload in both models. The use of optogenetics and 2D/3D contractility assays revealed opposing phenotypes in the two mutations. Gene expression analysis highlighted upregulation of CALM1, CASQ2 and CAMK2D, and downregulation of IRF8 in p.β-MHC-R453C mutants, whereas the opposite changes were detected in p.ACTC1-E99K mutants. Contrasting profiles of nuclear translocation of NFATc1 and MEF2 between the two HCM models suggest differential hypertrophic signaling pathway activation. Calcium transient abnormalities were rescued with combination of dantrolene and ranolazine, whilst mavacamten reduced the hyper-contractile phenotype of p.ACTC1-E99K hiPSC-CMs. CONCLUSIONS Our data show that hypercontractility and molecular signaling within HCM are not uniform between different gene mutations, suggesting that a 'one-size fits all' treatment underestimates the complexity of the disease. Understanding where the similarities (arrhythmogenesis, bioenergetics) and differences (contractility, molecular profile) lie will allow development of therapeutics that are directed towards common mechanisms or tailored to each disease variant, hence providing effective patient-specific therapy.
Collapse
Affiliation(s)
- Jamie R Bhagwan
- Division of Cancer & Stem Cells, Biodiscovery Institute, University of Nottingham, NG7 2RD, UK.
| | - Diogo Mosqueira
- Division of Cancer & Stem Cells, Biodiscovery Institute, University of Nottingham, NG7 2RD, UK.
| | - Karolina Chairez-Cantu
- Division of Cancer & Stem Cells, Biodiscovery Institute, University of Nottingham, NG7 2RD, UK
| | - Ingra Mannhardt
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, and DZHK (German Center for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Sara E Bodbin
- Division of Cancer & Stem Cells, Biodiscovery Institute, University of Nottingham, NG7 2RD, UK
| | - Mine Bakar
- Division of Cancer & Stem Cells, Biodiscovery Institute, University of Nottingham, NG7 2RD, UK
| | - James G W Smith
- Division of Cancer & Stem Cells, Biodiscovery Institute, University of Nottingham, NG7 2RD, UK; Faculty of Medicine and Health Sciences, Norwich Medical School, University of East Anglia,NR4 7UQ, UK
| | - Chris Denning
- Division of Cancer & Stem Cells, Biodiscovery Institute, University of Nottingham, NG7 2RD, UK.
| |
Collapse
|
34
|
Sparrow AJ, Watkins H, Daniels MJ, Redwood C, Robinson P. Mavacamten rescues increased myofilament calcium sensitivity and dysregulation of Ca 2+ flux caused by thin filament hypertrophic cardiomyopathy mutations. Am J Physiol Heart Circ Physiol 2020; 318:H715-H722. [PMID: 32083971 PMCID: PMC7099453 DOI: 10.1152/ajpheart.00023.2020] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thin filament hypertrophic cardiomyopathy (HCM) mutations increase myofilament Ca2+ sensitivity and alter Ca2+ handling and buffering. The myosin inhibitor mavacamten reverses the increased contractility caused by HCM thick filament mutations, and we here test its effect on HCM thin filament mutations where the mode of action is not known. Mavacamten (250 nM) partially reversed the increased Ca2+ sensitivity caused by HCM mutations Cardiac troponin T (cTnT) R92Q, and cardiac troponin I (cTnI) R145G in in vitro ATPase assays. The effect of mavacamten was also analyzed in cardiomyocyte models of cTnT R92Q and cTnI R145G containing cytoplasmic and myofilament specific Ca2+ sensors. While mavacamten rescued the hypercontracted basal sarcomere length, the reduced fractional shortening did not improve with mavacamten. Both mutations caused an increase in peak systolic Ca2+ detected at the myofilament, and this was completely rescued by 250 nM mavacamten. Systolic Ca2+ detected by the cytoplasmic sensor was also reduced by mavacamten treatment, although only R145G increased cytoplasmic Ca2+. There was also a reversal of Ca2+ decay time prolongation caused by both mutations at the myofilament but not in the cytoplasm. We thus show that mavacamten reverses some of the Ca2+-sensitive molecular and cellular changes caused by the HCM mutations, particularly altered Ca2+ flux at the myofilament. The reduction of peak systolic Ca2+ as a consequence of mavacamten treatment represents a novel mechanism by which the compound is able to reduce contractility, working synergistically with its direct effect on the myosin motor. NEW & NOTEWORTHY Mavacamten, a myosin inhibitor, is currently in phase-3 clinical trials as a pharmacotherapy for hypertrophic cardiomyopathy (HCM). Its efficacy in HCM caused by mutations in thin filament proteins is not known. We show in reductionist and cellular models that mavacamten can rescue the effects of thin filament mutations on calcium sensitivity and calcium handling although it only partially rescues the contractile cellular phenotype and, in some cases, exacerbates the effect of the mutation.
Collapse
Affiliation(s)
- Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Matthew J Daniels
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom.,Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| |
Collapse
|
35
|
Scardigli M, Cannazzaro S, Coppini R, Crocini C, Yan P, Loew LM, Sartiani L, Cerbai E, Pavone FS, Sacconi L, Ferrantini C. Arrhythmia susceptibility in a rat model of acute atrial dilation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 154:21-29. [PMID: 32063273 DOI: 10.1016/j.pbiomolbio.2019.08.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 08/17/2019] [Accepted: 08/27/2019] [Indexed: 12/11/2022]
Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia, associated with an increased risk of stroke and heart failure. Acute AF occurs in response to sudden increases of atrial hemodynamic load, leading to atrial stretch. The mechanisms of stretch-induced AF were investigated in large mammals with controversial results. We optimized an approach to monitor rat atrial electrical activity using a red-shifted voltage sensitive dye (VSD). The methodology includes cauterization of the main ventricular coronary arteries, allowing improved atrial staining by the VSD and appropriate atrial perfusion for long experiments. Next, we developed a rat model of acute biatrial dilation (ABD) through the insertion of latex balloons into both atria, which could be inflated with controlled volumes. A chronic model of atrial dilation (spontaneous hypertensive rats; SHR) was used for comparison. ABD was performed on atria from healthy Wistar-Kyoto (WKY) rats (WKY-ABD). The atria were characterized in terms of arrhythmias susceptibility, action potential duration and conduction velocity. The occurrence of arrhythmias in WKY-ABD was significantly higher compared to non-dilated WKY atria. In WKY-ABD we found a reduction of conduction velocity, similar to that observed in SHR atria, while action potential duration was unchanged. Low-dose caffeine was used to introduce a drop of CV in WKY atria (WKY-caff), quantitatively similar to the one observed after ABD, but no increased arrhythmia susceptibility was observed with caffeine only. In conclusion, CV decrease is not sufficient to promote arrhythmias; enlargement of atrial surface is essential to create a substrate for acute reentry-based arrhythmias.
Collapse
Affiliation(s)
- M Scardigli
- European Laboratory for Non-Linear Spectroscopy, 50019, Sesto Fiorentino (FI), Italy
| | - S Cannazzaro
- National Institute of Optics, National Research Council, 50125, Florence, Italy
| | - R Coppini
- Division of Pharmacology, Department "NeuroFarBa,", University of Florence, 50139, Florence, Italy
| | - C Crocini
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder, USA
| | - P Yan
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - L M Loew
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - L Sartiani
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - E Cerbai
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut School of Medicine, Farmington, CT, 06030, USA
| | - F S Pavone
- European Laboratory for Non-Linear Spectroscopy, 50019, Sesto Fiorentino (FI), Italy; National Institute of Optics, National Research Council, 50125, Florence, Italy; Department of Physics and Astronomy, University of Florence, 50019, Sesto Fiorentino (FI), Italy
| | - L Sacconi
- European Laboratory for Non-Linear Spectroscopy, 50019, Sesto Fiorentino (FI), Italy; National Institute of Optics, National Research Council, 50125, Florence, Italy
| | - C Ferrantini
- European Laboratory for Non-Linear Spectroscopy, 50019, Sesto Fiorentino (FI), Italy; Division of Physiology, Department of Experimental and Clinical Medicine, University of Florence, 50134, Florence, Italy.
| |
Collapse
|
36
|
Bhagwan JR, Collins E, Mosqueira D, Bakar M, Johnson BB, Thompson A, Smith JG, Denning C. Variable expression and silencing of CRISPR-Cas9 targeted transgenes identifies the AAVS1 locus as not an entirely safe harbour. F1000Res 2019; 8:1911. [PMID: 32789000 PMCID: PMC7401084 DOI: 10.12688/f1000research.19894.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/08/2019] [Indexed: 12/13/2022] Open
Abstract
Background: Diseases such as hypertrophic cardiomyopathy (HCM) can lead to severe outcomes including sudden death. The generation of human induced pluripotent stem cell (hiPSC) reporter lines can be useful for disease modelling and drug screening by providing physiologically relevant in vitro models of disease. The AAVS1 locus is cited as a safe harbour that is permissive for stable transgene expression, and hence is favoured for creating gene targeted reporter lines. Methods: We generated hiPSC reporters using a plasmid-based CRISPR/Cas9 nickase strategy. The first intron of PPP1R12C, the AAVS1 locus, was targeted with constructs expressing a genetically encoded calcium indicator (R-GECO1.0) or HOXA9-T2A-mScarlet reporter under the control of a pCAG or inducible pTRE promoter, respectively. Transgene expression was compared between clones before, during and/or after directed differentiation to mesodermal lineages. Results: Successful targeting to AAVS1 was confirmed by PCR and sequencing. Of 24 hiPSC clones targeted with pCAG-R-GECO1.0, only 20 expressed the transgene and in these, the percentage of positive cells ranged from 0% to 99.5%. Differentiation of a subset of clones produced cardiomyocytes, wherein the percentage of cells positive for R-GECO1.0 ranged from 2.1% to 93.1%. In the highest expressing R-GECO1.0 clones, transgene silencing occurred during cardiomyocyte differentiation causing a decrease in expression from 98.93% to 1.3%. In HOXA9-T2A-mScarlet hiPSC reporter lines directed towards mesoderm lineages, doxycycline induced a peak in transgene expression after two days but this reduced by up to ten-thousand-fold over the next 8-10 days. Nevertheless, for R-GECO1.0 lines differentiated into cardiomyocytes, transgene expression was rescued by continuous puromycin drug selection, which allowed the Ca 2+ responses associated with HCM to be investigated in vitro using single cell analysis. Conclusions: Targeted knock-ins to AAVS1 can be used to create reporter lines but variability between clones and transgene silencing requires careful attention by researchers seeking robust reporter gene expression.
Collapse
Affiliation(s)
- Jamie R. Bhagwan
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Emma Collins
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Diogo Mosqueira
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Mine Bakar
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Benjamin B. Johnson
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Alexander Thompson
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - James G.W. Smith
- Faculty of Medicine and Health Sciences, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Chris Denning
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| |
Collapse
|
37
|
Bhagwan JR, Collins E, Mosqueira D, Bakar M, Johnson BB, Thompson A, Smith JG, Denning C. Variable expression and silencing of CRISPR-Cas9 targeted transgenes identifies the AAVS1 locus as not an entirely safe harbour. F1000Res 2019; 8:1911. [PMID: 32789000 PMCID: PMC7401084 DOI: 10.12688/f1000research.19894.2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/22/2020] [Indexed: 01/11/2023] Open
Abstract
Background: Diseases such as hypertrophic cardiomyopathy (HCM) can lead to severe outcomes including sudden death. The generation of human induced pluripotent stem cell (hiPSC) reporter lines can be useful for disease modelling and drug screening by providing physiologically relevant in vitro models of disease. The AAVS1 locus is cited as a safe harbour that is permissive for stable transgene expression, and hence is favoured for creating gene targeted reporter lines. Methods: We generated hiPSC reporters using a plasmid-based CRISPR/Cas9 nickase strategy. The first intron of PPP1R12C, the AAVS1 locus, was targeted with constructs expressing a genetically encoded calcium indicator (R-GECO1.0) or HOXA9-T2A-mScarlet reporter under the control of a pCAG or inducible pTRE promoter, respectively. Transgene expression was compared between clones before, during and/or after directed differentiation to mesodermal lineages. Results: Successful targeting to AAVS1 was confirmed by PCR and sequencing. Of 24 hiPSC clones targeted with pCAG-R-GECO1.0, only 20 expressed the transgene and in these, the percentage of positive cells ranged from 0% to 99.5%. Differentiation of a subset of clones produced cardiomyocytes, wherein the percentage of cells positive for R-GECO1.0 ranged from 2.1% to 93.1%. In the highest expressing R-GECO1.0 clones, transgene silencing occurred during cardiomyocyte differentiation causing a decrease in expression from 98.93% to 1.3%. In HOXA9-T2A-mScarlet hiPSC reporter lines directed towards mesoderm lineages, doxycycline induced a peak in transgene expression after two days but this reduced by up to ten-thousand-fold over the next 8-10 days. Nevertheless, for R-GECO1.0 lines differentiated into cardiomyocytes, transgene expression was rescued by continuous puromycin drug selection, which allowed the Ca 2+ responses associated with HCM to be investigated in vitro using single cell analysis. Conclusions: Targeted knock-ins to AAVS1 can be used to create reporter lines but variability between clones and transgene silencing requires careful attention by researchers seeking robust reporter gene expression.
Collapse
Affiliation(s)
- Jamie R. Bhagwan
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Emma Collins
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Diogo Mosqueira
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Mine Bakar
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Benjamin B. Johnson
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Alexander Thompson
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| | - James G.W. Smith
- Faculty of Medicine and Health Sciences, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7UQ, UK
| | - Chris Denning
- Department of Stem Cells, Tissue Engineering and Modelling, Centre for Biomolecular Sciences, University of Nottingham, Nottingham, NG7 2RD, UK
| |
Collapse
|
38
|
Affiliation(s)
- Stuart G Campbell
- From the Department of Biomedical Engineering (S.G.C.), Yale University, New Haven, CT.,Department of Cellular and Molecular Physiology (S.G.C.), Yale School of Medicine, New Haven, CT
| | - Yibing Qyang
- From the Department of Biomedical Engineering (S.G.C.), Yale University, New Haven, CT.,Yale Stem Cell Center (Y.Q.), Yale University, New Haven, CT.,Vascular Biology and Therapeutics Program (Y.Q.), Yale University, New Haven, CT.,Yale Cardiovascular Research Center, Section of Cardiovascular Medicine, Department of Internal Medicine (Y.Q.), Yale School of Medicine, New Haven, CT
| | - J Travis Hinson
- The Jackson Laboratory for Genomic Medicine, Farmington, CT (J.T.H.).,Department of Cardiology, UConn Health, Farmington, CT (J.T.H.)
| |
Collapse
|