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  1. Article ; Online: Distinct cytoskeletal regulators of mechanical memory in cardiac fibroblasts and cardiomyocytes.

    Bouhrira, Nesrine / Vite, Alexia / Margulies, Kenneth B

    Basic research in cardiology

    2024  Volume 119, Issue 2, Page(s) 277–289

    Abstract: Recognizing that cells "feel" and respond to their mechanical environment, recent studies demonstrate that many cells exhibit a phenomenon of "mechanical memory" in which features induced by prior mechanical cues persist after the mechanical stimulus has ...

    Abstract Recognizing that cells "feel" and respond to their mechanical environment, recent studies demonstrate that many cells exhibit a phenomenon of "mechanical memory" in which features induced by prior mechanical cues persist after the mechanical stimulus has ceased. While there is a general recognition that different cell types exhibit different responses to changes in extracellular matrix stiffening, the phenomenon of mechanical memory within myocardial cell types has received little attention to date. To probe the dynamics of mechanical memory in cardiac fibroblasts (CFs) and cardiomyocytes derived from human induced pluripotent stem cells (iPSC-CMs), we employed a magnetorheological elastomer (MRE) cell culture substrate with tunable and reversible stiffness spanning the range from normal to diseased myocardium. In CFs, using increased cell area and increases in α-smooth muscle actin as markers of cellular responses to matrix stiffening, we found that induction of mechanical memory required seven days of stiff priming. Both induction and maintenance of persistent CF activation were blocked with the F-actin inhibitor cytochalasin D, while inhibitors of microtubule detyrosination had no impact on CFs. In iPSC-CMs, mechanical memory was invoked after only 24 h of stiff priming. Moreover, mechanical memory induction and maintenance were microtubule-dependent in CMs with no dependence on F-actin. Overall, these results identify the distinct temporal dynamics of mechanical memory in CFs and iPSC-CMs with different cytoskeletal mediators responsible for inducing and maintaining the stiffness-activated phenotype. Due to its flexibility, this model is broadly applicable to future studies interrogating mechanotransduction and mechanical memory in the heart and might inform strategies for attenuating the impact of load-induced pathology and excess myocardial stiffness.
    MeSH term(s) Humans ; Myocytes, Cardiac/metabolism ; Actins/metabolism ; Mechanotransduction, Cellular ; Cell Differentiation/physiology ; Induced Pluripotent Stem Cells ; Fibroblasts/metabolism
    Chemical Substances Actins
    Language English
    Publishing date 2024-02-13
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 189755-x
    ISSN 1435-1803 ; 0300-8428 ; 0175-9418
    ISSN (online) 1435-1803
    ISSN 0300-8428 ; 0175-9418
    DOI 10.1007/s00395-023-01030-0
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Functional Impact of Alternative Metabolic Substrates in Failing Human Cardiomyocytes.

    Vite, Alexia / Matsuura, Timothy R / Bedi, Kenneth C / Flam, Emily L / Arany, Zoltan / Kelly, Daniel P / Margulies, Kenneth B

    JACC. Basic to translational science

    2023  Volume 9, Issue 1, Page(s) 1–15

    Abstract: Recent studies suggest that metabolic dysregulation in patients with heart failure might contribute to myocardial contractile dysfunction. To understand the correlation between function and energy metabolism, we studied the impact of different fuel ... ...

    Abstract Recent studies suggest that metabolic dysregulation in patients with heart failure might contribute to myocardial contractile dysfunction. To understand the correlation between function and energy metabolism, we studied the impact of different fuel substrates on human nonfailing or failing cardiomyocytes. Consistent with the concept of metabolic flexibility, nonfailing myocytes exhibited excellent contractility in all fuels provided. However, impaired contractility was observed in failing myocytes when carbohydrates alone were used but was improved when additional substrates were added. This study demonstrates the functional significance of fuel utilization shifts in failing human cardiomyocytes.
    Language English
    Publishing date 2023-09-20
    Publishing country United States
    Document type Journal Article
    ISSN 2452-302X
    ISSN (online) 2452-302X
    DOI 10.1016/j.jacbts.2023.07.009
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Adult human cardiomyocyte mechanics in osteogenesis imperfecta.

    Lee, Benjamin W / Caporizzo, Matthew A / Chen, Christina Y / Bedi, Kenneth C / Peyster, Eliot G / Prosser, Benjamin L / Margulies, Kenneth B / Vite, Alexia

    American journal of physiology. Heart and circulatory physiology

    2023  Volume 325, Issue 4, Page(s) H814–H821

    Abstract: Osteogenesis imperfecta (OI) is an extracellular matrix disorder characterized by defects in collagen-1 transport or synthesis, resulting in bone abnormalities. Although reduced collagen in OI hearts has been associated with reduced myocardial stiffness ... ...

    Abstract Osteogenesis imperfecta (OI) is an extracellular matrix disorder characterized by defects in collagen-1 transport or synthesis, resulting in bone abnormalities. Although reduced collagen in OI hearts has been associated with reduced myocardial stiffness and left ventricular remodeling, its impact on cardiomyocyte (CM) function has not been studied. Here, we explore the tissue-level and CM-level properties of a heart from a deceased organ donor with OI type I. Proteomics and histology confirmed strikingly low expression of collagen 1. Trabecular stretch confirmed low stiffness on the tissue level. However, CMs retained normal viscoelastic properties as revealed by nanoindentation. Interestingly, OI CMs were hypercontractile relative to nonfailing controls after 24 h of culture. In response to 48 h of culture on surfaces with physiological (10 kPa) and pathological (50 kPa) stiffness, OI CMs demonstrated a greater reduction in contractility than nonfailing CMs, suggesting that OI CMs may have an impaired stress response. Levels of detyrosinated α-tubulin, known to be responsive to extracellular stiffness, were reduced in OI CMs. Together these data confirm multiple CM-level adaptations to low stiffness that extend our understanding of OI in the heart and how CMs respond to extracellular stiffness.
    MeSH term(s) Humans ; Adult ; Osteogenesis Imperfecta/metabolism ; Osteogenesis Imperfecta/pathology ; Myocytes, Cardiac/metabolism ; Collagen/metabolism ; Collagen Type I/metabolism ; Extracellular Matrix/metabolism ; Osteogenesis
    Chemical Substances Collagen (9007-34-5) ; Collagen Type I
    Language English
    Publishing date 2023-08-11
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 603838-4
    ISSN 1522-1539 ; 0363-6135
    ISSN (online) 1522-1539
    ISSN 0363-6135
    DOI 10.1152/ajpheart.00391.2023
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Biomechanical Impact of Pathogenic MYBPC3 Truncation Variant Revealed by Dynamically Tuning In Vitro Afterload.

    Ramachandran, Abhinay / Livingston, Carissa E / Vite, Alexia / Corbin, Elise A / Bennett, Alexander I / Turner, Kevin T / Lee, Benjamin W / Lam, Chi Keung / Wu, Joseph C / Margulies, Kenneth B

    Journal of cardiovascular translational research

    2023  Volume 16, Issue 4, Page(s) 828–841

    Abstract: Engineered cardiac microtissues were fabricated using pluripotent stem cells with a hypertrophic cardiomyopathy associated c. 2827 C>T; p.R943x truncation variant in myosin binding protein C ( ... ...

    Abstract Engineered cardiac microtissues were fabricated using pluripotent stem cells with a hypertrophic cardiomyopathy associated c. 2827 C>T; p.R943x truncation variant in myosin binding protein C (MYBPC3
    MeSH term(s) Humans ; Cardiomyopathy, Hypertrophic/genetics ; Cardiomyopathy, Hypertrophic/metabolism ; Mutation ; Pluripotent Stem Cells/metabolism ; Heart
    Language English
    Publishing date 2023-03-06
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 2422411-X
    ISSN 1937-5395 ; 1937-5387
    ISSN (online) 1937-5395
    ISSN 1937-5387
    DOI 10.1007/s12265-022-10348-4
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Extracellular stiffness induces contractile dysfunction in adult cardiomyocytes via cell-autonomous and microtubule-dependent mechanisms.

    Vite, Alexia / Caporizzo, Matthew A / Corbin, Elise A / Brandimarto, Jeffrey / McAfee, Quentin / Livingston, Carissa E / Prosser, Benjamin L / Margulies, Kenneth B

    Basic research in cardiology

    2022  Volume 117, Issue 1, Page(s) 41

    Abstract: The mechanical environment of the myocardium has a potent effect on cardiomyocyte form and function, yet an understanding of the cardiomyocyte responses to extracellular stiffening remains incomplete. We therefore employed a cell culture substrate with ... ...

    Abstract The mechanical environment of the myocardium has a potent effect on cardiomyocyte form and function, yet an understanding of the cardiomyocyte responses to extracellular stiffening remains incomplete. We therefore employed a cell culture substrate with tunable stiffness to define the cardiomyocyte responses to clinically relevant stiffness increments in the absence of cell-cell interactions. When cultured on substrates magnetically actuated to mimic the stiffness of diseased myocardium, isolated rat adult cardiomyocytes exhibited a time-dependent reduction of sarcomere shortening, characterized by slowed contraction and relaxation velocity, and alterations of the calcium transient. Cardiomyocytes cultured on stiff substrates developed increases in viscoelasticity and microtubule detyrosination in association with early increases in the α-tubulin detyrosinating enzyme vasohibin-2 (Vash2). We found that knockdown of Vash2 was sufficient to preserve contractile performance as well as calcium transient properties in the presence of extracellular substrate stiffening. Orthogonal prevention of detyrosination by overexpression of tubulin tyrosine ligase (TTL) was also able to preserve contractility and calcium homeostasis. These data demonstrate that a pathologic increment of extracellular stiffness induces early, cell-autonomous remodeling of adult cardiomyocytes that is dependent on detyrosination of α-tubulin.
    MeSH term(s) Animals ; Calcium ; Microtubules/pathology ; Microtubules/physiology ; Myocardium ; Myocytes, Cardiac/pathology ; Myocytes, Cardiac/physiology ; Rats ; Tubulin/chemistry
    Chemical Substances Tubulin ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2022-08-25
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 189755-x
    ISSN 1435-1803 ; 0300-8428 ; 0175-9418
    ISSN (online) 1435-1803
    ISSN 0300-8428 ; 0175-9418
    DOI 10.1007/s00395-022-00952-5
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: N-cadherin/catenin complex as a master regulator of intercalated disc function.

    Vite, Alexia / Radice, Glenn L

    Cell communication & adhesion

    2014  Volume 21, Issue 3, Page(s) 169–179

    Abstract: Intercellular adhesive junctions are essential for maintaining the physical integrity of tissues; this is particularly true for the heart that is under constant mechanical load. The correct functionality of the heart is dependent on the electrical and ... ...

    Abstract Intercellular adhesive junctions are essential for maintaining the physical integrity of tissues; this is particularly true for the heart that is under constant mechanical load. The correct functionality of the heart is dependent on the electrical and mechanical coordination of its constituent cardiomyocytes. The intercalated disc (ID) structure located at the termini of the rod-shaped adult cardiomyocyte contains various junctional proteins responsible for the integration of structural information and cell-cell communication. According to the classical description, the ID consists of three distinct junctional complexes: adherens junction (AJ), desmosome (Des), and gap junction (GJ) that work together to mediate mechanical and electrical coupling of cardiomyocytes. However, recent morphological and molecular studies indicate that AJ and Des components are capable of mixing together resulting in a "hybrid adhering junction" or "area composita." This review summarizes recent progress in understanding the in vivo function(s) of AJ components in cardiac homeostasis and disease.
    MeSH term(s) Adherens Junctions/metabolism ; Animals ; Cadherins/metabolism ; Catenins/metabolism ; Humans ; Myocytes, Cardiac/cytology ; Myocytes, Cardiac/metabolism
    Chemical Substances Cadherins ; Catenins
    Language English
    Publishing date 2014-04-28
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't ; Review
    ZDB-ID 2065474-1
    ISSN 1543-5180 ; 1061-5385 ; 1541-9061
    ISSN (online) 1543-5180
    ISSN 1061-5385 ; 1541-9061
    DOI 10.3109/15419061.2014.908853
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: New functions for alpha-catenins in health and disease: from cancer to heart regeneration.

    Vite, Alexia / Li, Jifen / Radice, Glenn L

    Cell and tissue research

    2015  Volume 360, Issue 3, Page(s) 773–783

    Abstract: Strong cell-cell adhesion mediated by adherens junctions is dependent on anchoring the transmembrane cadherin molecule to the underlying actin cytoskeleton. To do this, the cadherin cytoplasmic domain interacts with catenin proteins, which include α- ... ...

    Abstract Strong cell-cell adhesion mediated by adherens junctions is dependent on anchoring the transmembrane cadherin molecule to the underlying actin cytoskeleton. To do this, the cadherin cytoplasmic domain interacts with catenin proteins, which include α-catenin that binds directly to filamentous actin. Originally thought to be a static structure, the connection between the cadherin/catenin adhesion complex and the actin cytoskeleton is now considered to be dynamic and responsive to both intercellular and intracellular signals. Alpha-catenins are mechanosensing proteins that undergo conformational change in response to cytoskeletal tension thus modifying the linkage between the cadherin and the actin cytoskeleton. There are three α-catenin isoforms expressed in mouse and human: αE-catenin (CTNNA1), αN-catenin (CTNNA2) and αT-catenin (CTNNA3). This review summarizes recent progress in understanding the in vivo function(s) of α-catenins in tissue morphogenesis, homeostasis and disease. The role of α-catenin in the regulation of cellular proliferation will be discussed in the context of cancer and regeneration.
    MeSH term(s) Animals ; Health ; Heart/physiology ; Humans ; Models, Biological ; Neoplasms/metabolism ; Regeneration ; alpha Catenin/metabolism
    Chemical Substances alpha Catenin
    Language English
    Publishing date 2015-06
    Publishing country Germany
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ZDB-ID 125067-x
    ISSN 1432-0878 ; 0302-766X
    ISSN (online) 1432-0878
    ISSN 0302-766X
    DOI 10.1007/s00441-015-2123-x
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: 3158 Sunitinib-Induced Cardiotoxicity in an Engineered Cardiac Microtissue Model

    Carissa Livingston / Abhinay Ramachandran / Elise Corbin / Alexia Vite / Alexander Bennett / Kenneth Margulies

    Journal of Clinical and Translational Science, Vol 3, Pp 114-

    2019  Volume 115

    Abstract: OBJECTIVES/SPECIFIC AIMS: The aims of this study are threefold. Firstly, we are examining the effects of increased in vitro afterload (a proxy for hypertension) on human induced pluripotent stem cell cardiomyocyte (hiPSC-CM) response to sunitinib in a ... ...

    Abstract OBJECTIVES/SPECIFIC AIMS: The aims of this study are threefold. Firstly, we are examining the effects of increased in vitro afterload (a proxy for hypertension) on human induced pluripotent stem cell cardiomyocyte (hiPSC-CM) response to sunitinib in a durable and dynamic cardiac microtissue culture system. Secondly, we are exploring effects of repeat exposure and recovery of both sunitinib and afterload throughout the lifetime of the hiPSC-CM microtissue. Finally, we are assessing methods to prevent and treat sunitinib induced cardiotoxicity. Primary outcomes for this study are commonly utilized metrics of cardiotoxicity: degree of caspase activation, electrophysiology benchmarks for minimum voltage threshold and maximum capture rate, and microtissue force generation. METHODS/STUDY POPULATION: HiPSC-CMs are cultured and matured as 3D cardiac microtissues (CMTs) on a microtissue array. After maturation, cells are exposed to sunitinib doses of 0µM, 0.5µM, 1µM or 5µM for 12 hours. Concurrently with sunitinib dosing, increases in microtissue array stiffness are created with application of an external magnetic field. Afterload spring constants are fixed at pre-determined physiologic values ranging from 0.5µN/µm, to 5µN/µm. For Aim 1: Half of the CMTs are harvested at 8 hours after sunitinib dosing to conduct the caspase 3/7 assay, and the remainder are examined for 3 days following drug exposure to track temporal changes in electrophysiology and force generation. For Aim 2: After CMT maturation, 12-hour exposures to sunitinib are repeated three times at a fixed dose, with doses separated by one week. Concurrently with sunitinib dosing, increases or decreases in microtissue stiffness are created by changing the strength of an applied external magnetic field to create “ramp up” or “ramp down” stiffness conditions. Caspase assay and contractility metrics are measured at each timepoint. For Aim 3: Experimental conditions are conducted as described in Aim 1. Prior to the introduction of sunitinib, either carvedilol or an ...
    Keywords Medicine ; R
    Language English
    Publishing date 2019-03-01T00:00:00Z
    Publisher Cambridge University Press
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  9. Article ; Online: 3299 Dynamic Afterload Cardiac Microtissue Model To Examine Molecular Pathways of Heart Failure

    Abhinay Ramachandran / Carissa Livingston / Elise Corbin / Alexia Vite / Alex Bennett / Kenneth Margulies

    Journal of Clinical and Translational Science, Vol 3, Pp 9-

    2019  Volume 9

    Abstract: OBJECTIVES/SPECIFIC AIMS: This project aims to determine the key molecular pathways that link increased myocardial wall stress to cardiomyocyte hypertrophy and subsequent heart failure. We will use a cardiac microtissue (CMT) model with dynamically ... ...

    Abstract OBJECTIVES/SPECIFIC AIMS: This project aims to determine the key molecular pathways that link increased myocardial wall stress to cardiomyocyte hypertrophy and subsequent heart failure. We will use a cardiac microtissue (CMT) model with dynamically tunable cantilever stiffness to examine changes in CMT hypertrophy and electro-mechanical properties in response to increased afterload (cantilever stiffness). Subsequently, we will determine if inhibition of pro-hypertrophic or anti-hypertrophic pathways alter the hypertrophic response to increased afterload. Primary outcomes for this study are static/dynamic force, minimum electric field strength (VT), maximum capture rate (MCR), average cell area, and tissue cross-sectional thickness, and secondary outcomes are degree of myoblast activation and apoptosis. METHODS/STUDY POPULATION: CMT platforms will be fabricated using iron-doped polydimethylsiloxane (PDMS) to create magnetically tunable cantilevers. Cantilever stiffness will be increased with the application of an external magnetic field. Cantilever stiffness will be measured using a capacitance probe, where the force required to deflect both the cantilever and calibration probe is in accordance with Hooke’s Law. Human induced pluripotent stem cell cardiomyocyte (hiPSC-CMs) will be cultured and matured as 3D CMTs. In-vitro static/dynamic force generation will also be calculated by measuring the deflection of the cantilevers and applying Hooke’s law. CMTs will be paced using carbon electrodes to obtain VT and MCR. Structural data will be obtained using immunostaining and confocal microscopy. Finally, we will use pharmacologic inhibitors to inhibit molecular pathways that we identified in prior genetic screens such as ABCC8 (anti-hypertrophic mediator) and C1QTNF9 (pro-hypertrophic mediator). We will examine each of these pathways in low- and high-stiffness conditions. RESULTS/ANTICIPATED RESULTS: We believe increased afterload will cause significant hypertrophy, measured by increases in CMT cross-sectional ...
    Keywords Medicine ; R
    Subject code 621
    Language English
    Publishing date 2019-03-01T00:00:00Z
    Publisher Cambridge University Press
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: α-Catenin-dependent cytoskeletal tension controls Yap activity in the heart.

    Vite, Alexia / Zhang, Caimei / Yi, Roslyn / Emms, Sabrina / Radice, Glenn L

    Development (Cambridge, England)

    2018  Volume 145, Issue 5

    Abstract: Shortly after birth, muscle cells of the mammalian heart lose their ability to divide. At the same time, the N-cadherin/catenin cell adhesion complex accumulates at the cell termini, creating a specialized type of cell-cell contact called the ... ...

    Abstract Shortly after birth, muscle cells of the mammalian heart lose their ability to divide. At the same time, the N-cadherin/catenin cell adhesion complex accumulates at the cell termini, creating a specialized type of cell-cell contact called the intercalated disc (ICD). To investigate the relationship between ICD maturation and proliferation, αE-catenin (
    MeSH term(s) Adaptor Proteins, Signal Transducing/metabolism ; Adaptor Proteins, Signal Transducing/physiology ; Animals ; Animals, Newborn ; Cell Communication/genetics ; Cell Cycle Proteins ; Cells, Cultured ; Cytoskeleton/metabolism ; Mice ; Mice, Inbred C57BL ; Mice, Knockout ; Myocardium/metabolism ; Myocytes, Cardiac/metabolism ; Myocytes, Cardiac/physiology ; Phosphoproteins/metabolism ; Phosphoproteins/physiology ; YAP-Signaling Proteins ; alpha Catenin/genetics ; alpha Catenin/physiology
    Chemical Substances Adaptor Proteins, Signal Transducing ; CTNNA3 protein, mouse ; Cell Cycle Proteins ; Ctnna1 protein, mouse ; Phosphoproteins ; YAP-Signaling Proteins ; Yap1 protein, mouse ; alpha Catenin
    Language English
    Publishing date 2018-03-08
    Publishing country England
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 90607-4
    ISSN 1477-9129 ; 0950-1991
    ISSN (online) 1477-9129
    ISSN 0950-1991
    DOI 10.1242/dev.149823
    Database MEDical Literature Analysis and Retrieval System OnLINE

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