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  1. Article ; Online: Targeted CRISPR activation is functional in engineered human pluripotent stem cells but undergoes silencing after differentiation into cardiomyocytes and endothelium.

    Karbassi, Elaheh / Padgett, Ruby / Bertero, Alessandro / Reinecke, Hans / Klaiman, Jordan M / Yang, Xiulan / Hauschka, Stephen D / Murry, Charles E

    Cellular and molecular life sciences : CMLS

    2024  Volume 81, Issue 1, Page(s) 95

    Abstract: Human induced pluripotent stem cells (hiPSCs) offer opportunities to study human biology where primary cell types are limited. CRISPR technology allows forward genetic screens using engineered Cas9-expressing cells. Here, we sought to generate a CRISPR ... ...

    Abstract Human induced pluripotent stem cells (hiPSCs) offer opportunities to study human biology where primary cell types are limited. CRISPR technology allows forward genetic screens using engineered Cas9-expressing cells. Here, we sought to generate a CRISPR activation (CRISPRa) hiPSC line to activate endogenous genes during pluripotency and differentiation. We first targeted catalytically inactive Cas9 fused to VP64, p65 and Rta activators (dCas9-VPR) regulated by the constitutive CAG promoter to the AAVS1 safe harbor site. These CRISPRa hiPSC lines effectively activate target genes in pluripotency, however the dCas9-VPR transgene expression is silenced after differentiation into cardiomyocytes and endothelial cells. To understand this silencing, we systematically tested different safe harbor sites and different promoters. Targeting to safe harbor sites hROSA26 and CLYBL loci also yielded hiPSCs that expressed dCas9-VPR in pluripotency but silenced during differentiation. Muscle-specific regulatory cassettes, derived from cardiac troponin T or muscle creatine kinase promoters, were also silent after differentiation when dCas9-VPR was introduced. In contrast, in cell lines where the dCas9-VPR sequence was replaced with cDNAs encoding fluorescent proteins, expression persisted during differentiation in all loci and with all promoters. Promoter DNA was hypermethylated in CRISPRa-engineered lines, and demethylation with 5-azacytidine enhanced dCas9-VPR gene expression. In summary, the dCas9-VPR cDNA is readily expressed from multiple loci during pluripotency but induces silencing in a locus- and promoter-independent manner during differentiation to mesoderm derivatives. Researchers intending to use this CRISPRa strategy during stem cell differentiation should pilot their system to ensure it remains active in their population of interest.
    MeSH term(s) Humans ; Myocytes, Cardiac ; Endothelial Cells ; Induced Pluripotent Stem Cells ; Pluripotent Stem Cells ; Cell Differentiation/genetics ; Endothelium
    Language English
    Publishing date 2024-02-19
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 1358415-7
    ISSN 1420-9071 ; 1420-682X
    ISSN (online) 1420-9071
    ISSN 1420-682X
    DOI 10.1007/s00018-023-05101-2
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Cardiac involvement in female carriers of Duchenne or Becker muscular dystrophy.

    Childers, Martin K / Klaiman, Jordan M

    Muscle & nerve

    2017  Volume 55, Issue 6, Page(s) 777–779

    MeSH term(s) Female ; Heart ; Heterozygote ; Humans ; Muscular Dystrophy, Duchenne
    Language English
    Publishing date 2017-05-05
    Publishing country United States
    Document type Editorial ; Comment
    ZDB-ID 438353-9
    ISSN 1097-4598 ; 0148-639X
    ISSN (online) 1097-4598
    ISSN 0148-639X
    DOI 10.1002/mus.25661
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  3. Article ; Online: Comparison of dystrophin expression following gene editing and gene replacement in an aged preclinical DMD animal model.

    Bengtsson, Niclas E / Crudele, Julie M / Klaiman, Jordan M / Halbert, Christine L / Hauschka, Stephen D / Chamberlain, Jeffrey S

    Molecular therapy : the journal of the American Society of Gene Therapy

    2022  Volume 30, Issue 6, Page(s) 2176–2185

    Abstract: Gene editing has shown promise for correcting or bypassing dystrophin mutations in Duchenne muscular dystrophy (DMD). However, preclinical studies have focused on young animals with limited muscle fibrosis and wasting, thereby favoring muscle ... ...

    Abstract Gene editing has shown promise for correcting or bypassing dystrophin mutations in Duchenne muscular dystrophy (DMD). However, preclinical studies have focused on young animals with limited muscle fibrosis and wasting, thereby favoring muscle transduction, myonuclear editing, and prevention of disease progression. Here, we explore muscle-specific dystrophin gene editing following intramuscular delivery of AAV6:CK8e-CRISPR/SaCas9 in 3- and 8-year-old dystrophic CXMD dogs and provide a qualitative comparison to AAV6:CK8e-micro-dystrophin gene replacement at 6 weeks post-treatment. Gene editing restored the dystrophin reading frame in ∼1.3% of genomes and in up to 4.0% of dystrophin transcripts following excision of a 105-kb mutation containing region spanning exons 6-8. However, resulting dystrophin expression levels and effects on muscle pathology were greater with the use of micro-dystrophin gene transfer. This study demonstrates that our muscle-specific multi-exon deletion strategy can correct a frequently mutated region of the dystrophin gene in an aged large animal DMD model, but underscores that further enhancements are required to reach efficiencies comparable to AAV micro-dystrophin. Our observations also indicate that treatment efficacy and state of muscle pathology at the time of intervention are linked, suggesting the need for additional methodological optimizations related to age and disease progression to achieve relevant clinical translation of CRISPR-based therapies to all DMD patients.
    MeSH term(s) Aging ; Animals ; CRISPR-Cas Systems ; Disease Models, Animal ; Disease Progression ; Dogs ; Dystrophin/genetics ; Gene Editing/methods ; Muscle, Skeletal/metabolism ; Muscular Dystrophy, Duchenne/genetics ; Muscular Dystrophy, Duchenne/therapy
    Chemical Substances Dystrophin
    Language English
    Publishing date 2022-02-08
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 2010592-7
    ISSN 1525-0024 ; 1525-0016
    ISSN (online) 1525-0024
    ISSN 1525-0016
    DOI 10.1016/j.ymthe.2022.02.003
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Temperature-induced cardiac remodelling in fish.

    Keen, Adam N / Klaiman, Jordan M / Shiels, Holly A / Gillis, Todd E

    The Journal of experimental biology

    2017  Volume 220, Issue Pt 2, Page(s) 147–160

    Abstract: Thermal acclimation causes the heart of some fish species to undergo significant remodelling. This includes changes in electrical activity, energy utilization and structural properties at the gross and molecular level of organization. The purpose of this ...

    Abstract Thermal acclimation causes the heart of some fish species to undergo significant remodelling. This includes changes in electrical activity, energy utilization and structural properties at the gross and molecular level of organization. The purpose of this Review is to summarize the current state of knowledge of temperature-induced structural remodelling in the fish ventricle across different levels of biological organization, and to examine how such changes result in the modification of the functional properties of the heart. The structural remodelling response is thought to be responsible for changes in cardiac stiffness, the Ca
    MeSH term(s) Acclimatization ; Animals ; Climate Change ; Fishes/physiology ; Heart/physiology ; Temperature ; Ventricular Remodeling
    Language English
    Publishing date 2017-01-15
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 218085-6
    ISSN 1477-9145 ; 0022-0949
    ISSN (online) 1477-9145
    ISSN 0022-0949
    DOI 10.1242/jeb.128496
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: The influence of PKA treatment on the Ca2+ activation of force generation by trout cardiac muscle.

    Gillis, Todd E / Klaiman, Jordan M

    The Journal of experimental biology

    2011  Volume 214, Issue Pt 12, Page(s) 1989–1996

    Abstract: β-Adrenergic stimulation of the mammalian heart increases heart rate, the strength of contraction as well as the kinetics of force generation and relaxation. These effects are due to the phosphorylation of select membrane and thin filament proteins by ... ...

    Abstract β-Adrenergic stimulation of the mammalian heart increases heart rate, the strength of contraction as well as the kinetics of force generation and relaxation. These effects are due to the phosphorylation of select membrane and thin filament proteins by cAMP-activated protein kinase (PKA). At the level of the sarcomere, it is typically the phosphorylation of cardiac myosin binding protein C (cMyBP-C) and cardiac troponin I (cTnI) that is responsible for the change in the kinetics of contraction and relaxation. Trout cTnI (ScTnI) lacks two critical PKA targets within the N-terminus of the protein that, when phosphorylated in mammalian cTnI, cause a reduction in myofilament Ca(2+) affinity. To determine what role the contractile element plays in the response of the trout heart to β-adrenergic stimulation, we characterized the influence of PKA treatment on the Ca(2+) activation of skinned preparations dissected from ventricular trabeculae. In these experiments, isometric force generation and the rate of force development were measured over a range of Ca(2+) concentrations. The results demonstrate that PKA treatment does not influence the Ca(2+) sensitivity of force generation but it decreases maximum force generation by 25% and the rate of force re-development at maximal activation by 46%. Analysis of the trabeculae preparations for phosphoproteins revealed that PKA treatment phosphorylated myosin light chain 2 but not cTnI or cMyBP-C. These results indicate that the function of the trout cardiac contractile element is altered by PKA phosphorylation but in a manner different from that in mammalian heart.
    MeSH term(s) Animals ; Calcium/metabolism ; Cardiac Myosins/metabolism ; Carrier Proteins/metabolism ; Cyclic AMP-Dependent Protein Kinases/metabolism ; Female ; Heart/physiology ; Male ; Myocardial Contraction ; Myocardium/metabolism ; Myocytes, Cardiac/physiology ; Myosin Light Chains/metabolism ; Oncorhynchus mykiss/physiology ; Phosphorylation ; Troponin I/metabolism
    Chemical Substances Carrier Proteins ; Myosin Light Chains ; Troponin I ; myosin light chain 2 ; myosin-binding protein C ; Cyclic AMP-Dependent Protein Kinases (EC 2.7.11.11) ; Cardiac Myosins (EC 3.6.1.-) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2011-06-15
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 218085-6
    ISSN 1477-9145 ; 0022-0949
    ISSN (online) 1477-9145
    ISSN 0022-0949
    DOI 10.1242/jeb.052084
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Cold acclimation increases cardiac myofilament function and ventricular pressure generation in trout.

    Klaiman, Jordan M / Pyle, W Glen / Gillis, Todd E

    The Journal of experimental biology

    2014  Volume 217, Issue Pt 23, Page(s) 4132–4140

    Abstract: Reducing temperature below the optimum of most vertebrate hearts impairs contractility and reduces organ function. However, a number of fish species, including the rainbow trout, can seasonally acclimate to low temperature. Such ability requires ... ...

    Abstract Reducing temperature below the optimum of most vertebrate hearts impairs contractility and reduces organ function. However, a number of fish species, including the rainbow trout, can seasonally acclimate to low temperature. Such ability requires modification of physiological systems to compensate for the thermodynamic effects of temperature on biological processes. The current study tested the hypothesis that rainbow trout compensate for the direct effect of cold temperature by increasing cardiac contractility during cold acclimation. We examined cardiac contractility, following thermal acclimation (4, 11 and 17°C), by measuring the Ca(2+) sensitivity of force generation by chemically skinned cardiac trabeculae as well as ventricular pressure generation using a modified Langendorff preparation. We demonstrate, for the first time, that the Ca(2+) sensitivity of force generation was significantly higher in cardiac trabeculae from 4°C-acclimated trout compared with those acclimated to 11 or 17°C, and that this functional change occurred in parallel with a decrease in the level of cardiac troponin T phosphorylation. In addition, we show that the magnitude and rate of ventricular pressure generation was greater in hearts from trout acclimated to 4°C compared with those from animals acclimated to 11 or 17°C. Taken together, these results suggest that enhanced myofilament function, caused by modification of existing contractile proteins, is at least partially responsible for the observed increase in pressure generation after acclimation to 4°C. In addition, by examining the phenotypic plasticity of a comparative model we have identified a strategy, used in vivo, by which the force-generating capacity of cardiac muscle can be increased.
    MeSH term(s) Acclimatization/physiology ; Actin Cytoskeleton/physiology ; Animals ; Calcium/metabolism ; Cold Temperature ; Heart/physiology ; Myocardial Contraction ; Myocardium/metabolism ; Myofibrils/physiology ; Oncorhynchus mykiss/physiology ; Ventricular Pressure
    Chemical Substances Calcium (SY7Q814VUP)
    Language English
    Publishing date 2014-12-01
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 218085-6
    ISSN 1477-9145 ; 0022-0949
    ISSN (online) 1477-9145
    ISSN 0022-0949
    DOI 10.1242/jeb.109041
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  7. Article: Cell based dATP delivery as a therapy for chronic heart failure.

    Mhatre, Ketaki N / Mathieu, Julie / Martinson, Amy / Flint, Galina / Blakley, Leslie P / Tabesh, Arash / Reinecke, Hans / Yang, Xiulan / Guan, Xuan / Murali, Eesha / Klaiman, Jordan M / Odom, Guy L / Brown, Mary Beth / Tian, Rong / Hauschka, Stephen D / Raftery, Daniel / Moussavi-Harami, Farid / Regnier, Michael / Murry, Charles E

    bioRxiv : the preprint server for biology

    2023  

    Abstract: Transplanted human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) improve ventricular performance when delivered acutely post-myocardial infarction but are ineffective in chronic myocardial infarction/heart failure. 2'-deoxy-ATP (dATP) activates ...

    Abstract Transplanted human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) improve ventricular performance when delivered acutely post-myocardial infarction but are ineffective in chronic myocardial infarction/heart failure. 2'-deoxy-ATP (dATP) activates cardiac myosin and potently increases contractility. Here we engineered hPSC-CMs to overexpress ribonucleotide reductase, the enzyme controlling dATP production. In vivo, dATP-producing CMs formed new myocardium that transferred dATP to host cardiomyocytes via gap junctions, increasing their dATP levels. Strikingly, when transplanted into chronically infarcted hearts, dATP-producing grafts increased left ventricular function, whereas heart failure worsened with wild-type grafts or vehicle injections. dATP-donor cells recipients had greater voluntary exercise, improved cardiac metabolism, reduced pulmonary congestion and pathological cardiac hypertrophy, and improved survival. This combination of remuscularization plus enhanced host contractility offers a novel approach to treating the chronically failing heart.
    Language English
    Publishing date 2023-04-28
    Publishing country United States
    Document type Preprint
    DOI 10.1101/2023.04.24.538108
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Gene editing to prevent ventricular arrhythmias associated with cardiomyocyte cell therapy.

    Marchiano, Silvia / Nakamura, Kenta / Reinecke, Hans / Neidig, Lauren / Lai, Michael / Kadota, Shin / Perbellini, Filippo / Yang, Xiulan / Klaiman, Jordan M / Blakely, Leslie P / Karbassi, Elaheh / Fields, Paul A / Fenix, Aidan M / Beussman, Kevin M / Jayabalu, Anu / Kalucki, Faith A / Potter, Jennifer C / Futakuchi-Tsuchida, Akiko / Weber, Gerhard J /
    Dupras, Sarah / Tsuchida, Hiroshi / Pabon, Lil / Wang, Lili / Knollmann, Björn C / Kattman, Steven / Thies, R Scott / Sniadecki, Nathan / MacLellan, W Robb / Bertero, Alessandro / Murry, Charles E

    Cell stem cell

    2023  Volume 30, Issue 4, Page(s) 396–414.e9

    Abstract: Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) offer a promising cell-based therapy for myocardial infarction. However, the presence of transitory ventricular arrhythmias, termed engraftment arrhythmias (EAs), hampers clinical applications. ...

    Abstract Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) offer a promising cell-based therapy for myocardial infarction. However, the presence of transitory ventricular arrhythmias, termed engraftment arrhythmias (EAs), hampers clinical applications. We hypothesized that EA results from pacemaker-like activity of hPSC-CMs associated with their developmental immaturity. We characterized ion channel expression patterns during maturation of transplanted hPSC-CMs and used pharmacology and genome editing to identify those responsible for automaticity in vitro. Multiple engineered cell lines were then transplanted in vivo into uninjured porcine hearts. Abolishing depolarization-associated genes HCN4, CACNA1H, and SLC8A1, along with overexpressing hyperpolarization-associated KCNJ2, creates hPSC-CMs that lack automaticity but contract when externally stimulated. When transplanted in vivo, these cells engrafted and coupled electromechanically with host cardiomyocytes without causing sustained EAs. This study supports the hypothesis that the immature electrophysiological prolife of hPSC-CMs mechanistically underlies EA. Thus, targeting automaticity should improve the safety profile of hPSC-CMs for cardiac remuscularization.
    MeSH term(s) Humans ; Animals ; Swine ; Myocytes, Cardiac/metabolism ; Gene Editing ; Cell Line ; Arrhythmias, Cardiac/genetics ; Arrhythmias, Cardiac/therapy ; Arrhythmias, Cardiac/metabolism ; Cell- and Tissue-Based Therapy ; Cell Differentiation/genetics
    Language English
    Publishing date 2023-04-06
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, N.I.H., Extramural
    ZDB-ID 2375354-7
    ISSN 1875-9777 ; 1934-5909
    ISSN (online) 1875-9777
    ISSN 1934-5909
    DOI 10.1016/j.stem.2023.03.010
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  9. Article ; Online: Gene editing to prevent ventricular arrhythmias associated with cardiomyocyte cell therapy.

    Marchiano, Silvia / Nakamura, Kenta / Reinecke, Hans / Neidig, Lauren / Lai, Michael / Kadota, Shin / Perbellini, Filippo / Yang, Xiulan / Klaiman, Jordan M / Blakely, Leslie P / Karbassi, Elaheh / Fields, Paul A / Fenix, Aidan M / Beussman, Kevin M / Jayabalu, Anu / Kalucki, Faith A / Potter, Jennifer C / Futakuchi-Tsuchida, Akiko / Weber, Gerhard J /
    Dupras, Sarah / Tsuchida, Hiroshi / Pabon, Lil / Wang, Lili / Knollmann, Björn C / Kattman, Steven / Thies, R Scott / Sniadecki, Nathan / MacLellan, W Robb / Bertero, Alessandro / Murry, Charles E

    Cell stem cell

    2023  Volume 30, Issue 5, Page(s) 741

    Language English
    Publishing date 2023-04-25
    Publishing country United States
    Document type Published Erratum
    ZDB-ID 2375354-7
    ISSN 1875-9777 ; 1934-5909
    ISSN (online) 1875-9777
    ISSN 1934-5909
    DOI 10.1016/j.stem.2023.04.010
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  10. Article ; Online: Effect of cold acclimation on troponin I isoform expression in striated muscle of rainbow trout.

    Alderman, Sarah L / Klaiman, Jordan M / Deck, Courtney A / Gillis, Todd E

    American journal of physiology. Regulatory, integrative and comparative physiology

    2012  Volume 303, Issue 2, Page(s) R168–76

    Abstract: In vertebrates each of the three striated muscle types (fast skeletal, slow skeletal, and cardiac) contain distinct isoforms of a number of different contractile proteins including troponin I (TnI). The functional characteristics of these proteins have a ...

    Abstract In vertebrates each of the three striated muscle types (fast skeletal, slow skeletal, and cardiac) contain distinct isoforms of a number of different contractile proteins including troponin I (TnI). The functional characteristics of these proteins have a significant influence on muscle function and contractility. The purpose of this study was to characterize which TnI gene and protein isoforms are expressed in the different muscle types of rainbow trout (Oncorhynchus mykiss) and to determine whether isoform expression changes in response to cold acclimation (4°C). Semiquantitative real-time PCR was used to characterize the expression of seven different TnI genes. The sequence of these genes, cloned from Atlantic salmon (Salmo salar) and rainbow trout, were obtained from the National Center for Biotechnology Information databases. One-dimensional gel electrophoresis and tandem mass spectrometry were used to identify the TnI protein isoforms expressed in each muscle type. Interestingly, the results indicate that each muscle type expresses the gene transcripts of up to seven TnI isoforms. There are significant differences, however, in the expression pattern of these genes between muscle types. In addition, cold acclimation was found to increase the expression of specific gene transcripts in each muscle type. The proteomics analysis demonstrates that fast skeletal and cardiac muscle contain three TnI isoforms, whereas slow skeletal muscle contains four. No other vertebrate muscle to date has been found to express as many TnI protein isoforms. Overall this study underscores the complex molecular composition of teleost striated muscle and suggests there is an adaptive value to the unique TnI profiles of each muscle type.
    MeSH term(s) Acclimatization/physiology ; Amino Acid Sequence ; Animals ; Cold Temperature ; Female ; Gene Expression Regulation/physiology ; Molecular Sequence Data ; Muscle Contraction/physiology ; Muscle Fibers, Fast-Twitch/metabolism ; Muscle Fibers, Slow-Twitch/metabolism ; Muscle, Skeletal/metabolism ; Myocardium/metabolism ; Oncorhynchus mykiss/physiology ; Protein Isoforms/metabolism ; Salmon ; Troponin I/analysis ; Troponin I/genetics ; Troponin I/metabolism
    Chemical Substances Protein Isoforms ; Troponin I
    Language English
    Publishing date 2012-05-16
    Publishing country United States
    Document type Comparative Study ; Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 603839-6
    ISSN 1522-1490 ; 0363-6119
    ISSN (online) 1522-1490
    ISSN 0363-6119
    DOI 10.1152/ajpregu.00127.2012
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