scholarly journals Effects of Extended Pharmacological Disruption of Zebrafish Embryonic Heart Biomechanical Environment on Cardiac Function, Morphology and Gene Expression

2021 ◽  
Author(s):  
Yoke Yin Foo ◽  
Efthymios Motakis ◽  
Zenia Tiang ◽  
Shuhao Shen ◽  
Jason Kuan Han Lai ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cardiac Function ◽  
Embryonic Heart

Long-term levosimendan treatment improves systolic function and myocardial relaxation in mice with cardiomyocyte-specific disruption of the Serca2 gene

2013 ◽  
Vol 115 (10) ◽  
pp. 1572-1580 ◽  
Author(s):  
Vigdis Hillestad ◽  
Frank Kramer ◽  
Stefan Golz ◽  
Andreas Knorr ◽  
Kristin B. Andersson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Failure ◽  
Cardiac Function ◽  
Diastolic Dysfunction ◽  
Systolic Function ◽  
Cytosolic Calcium ◽  
Left Ventricular ◽  
Pressure Measurements ◽  
Human Heart Failure

In human heart failure (HF), reduced cardiac function has, at least partly, been ascribed to altered calcium homeostasis in cardiomyocytes. The effects of the calcium sensitizer levosimendan on diastolic dysfunction caused by reduced removal of calcium from cytosol in early diastole are not well known. In this study, we investigated the effect of long-term levosimendan treatment in a murine model of HF where the sarco(endo)plasmatic reticulum ATPase ( Serca) gene is specifically disrupted in the cardiomyocytes, leading to reduced removal of cytosolic calcium. After induction of Serca2 gene disruption, these mice develop marked diastolic dysfunction as well as impaired contractility. SERCA2 knockout (SERCA2KO) mice were treated with levosimendan or vehicle from the time of KO induction. At the 7-wk end point, cardiac function was assessed by echocardiography and pressure measurements. Vehicle-treated SERCA2KO mice showed significantly diminished left-ventricular (LV) contractility, as shown by decreased ejection fraction, stroke volume, and cardiac output. LV pressure measurements revealed a marked increase in the time constant (τ) of isovolumetric pressure decay, showing impaired relaxation. Levosimendan treatment significantly improved all three systolic parameters. Moreover, a significant reduction in τ toward normalization indicated improved relaxation. Gene-expression analysis, however, revealed an increase in genes related to production of the ECM in animals treated with levosimendan. In conclusion, long-term levosimendan treatment improves both contractility and relaxation in a heart-failure model with marked diastolic dysfunction due to reduced calcium transients. However, altered gene expression related to fibrosis was observed.

Abstract 314: BRaf Plays a Major Role in Gene Expression in Cardiomyocytes in Mouse Hearts in vivo

2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Michelle A Hardyman ◽  
Stephen J Fuller ◽  
Daniel N Meijles ◽  
Kerry A Rostron ◽  
Sam J Leonard ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cardiac Hypertrophy ◽  
Cardiac Function ◽  
Left Ventricular ◽  
Braf Mutations ◽  
Gene Markers ◽  
Lv Mass ◽  
Cardiac Volumes

Introduction: Raf kinases lie upstream of ERK1/2 with BRaf being the most highly expressed and having the highest basal activity. V600E BRaf mutations constitutively activate ERK1/2 and are common in cancer. The role of BRaf in the adult heart is yet to be established. ERK1/2 regulate cardiomyocyte gene expression, promoting cardiac hypertrophy and cardioprotection, but effects of ERK1/2 may depend on signal strength. Hypothesis: Our hypotheses are that BRaf is critical in regulating ERK1/2 signaling in cardiomyocytes and, whilst moderate ERK1/2 activity is beneficial, excessive ERK1/2 activity is detrimental to the heart. Methods: We generated heterozygote mice for tamoxifen- (Tam-) inducible cardiomyocyte-specific knockin of V600E in the endogenous BRaf gene. Mice (12 wks) received 2 injections of Tam or vehicle on consecutive days (n=4-10 per group). Kinase activities and mRNA expression were assessed by immunoblotting and qPCR. Echocardiography was performed (Vevo2100). M-mode images (short axis view) were analyzed; data for each mouse were normalized to the mean of 2 baseline controls. Results: V600E knockin did not affect overall BRaf or cRaf levels in mouse hearts, but significantly increased ERK1/2 activities within 48 h (1.51±0.05 fold). Concurrently, mRNAs for hypertrophic gene markers including BNP and immediate early genes (IEGs) increased signficantly. At 72 h, expression of BNP, Fosl1, Myc, Ereg and CTGF increased further, other IEGs (Jun, Fos, Egr1, Atf3) declined, and ANF was upregulated. In contrast, expression of α and β myosin heavy chain mRNAs was substantially downregulated (0.46/0.41±0.05 relative to controls). Within 72 h, left ventricular (LV) mass and diastolic LV wall thickness had increased (1.23±0.05 relative to controls), but cardiac function was severely compromised with significant decreases in ejection fraction and cardiac output (0.53/0.68±0.09 relative to controls) associated with increased LV internal diameters and cardiac volumes. Conclusions: Endogenous cardiomyocyte BRaf is sufficient to activate ERK1/2 in mouse hearts and induce cardiac hypertrophy associated with dynamic temporal changes in gene expression. However, excessive activation of ERK1/2 in isolation is detrimental to cardiac function.

Abstract 247: Scaffold-stiffness Dependent Notch1 Activation Regulates Cardiogenic Gene Expression In Cardiac Progenitor Cells

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Archana V Boopathy ◽  
Pao L Che ◽  
Yoshie Narui ◽  
Khalid Salaita ◽  
Michael E Davis
Keyword(s):  
Gene Expression ◽  
Smooth Muscle ◽  
Cardiac Function ◽  
Progenitor Cells ◽  
Adult Stem Cells ◽  
Cardiac Progenitor Cells ◽  
Critical Pathway ◽  
Cardiac Gene Expression ◽  
Self Assembling ◽  
Cardiac Gene

Rationale: Cardiac progenitor cells (CPCs) are multipotent, self-renewing cells that can regenerate the myocardium and improve cardiac function in animal models of myocardial infarction (MI). However, limited survival of stem/progenitor cells inhibits cardiac regeneration. Force dependent Notch activation promotes cardiac development and cardiac gene expression in many adult stem cells. As dysregulation of Notch signaling leads to embryonic lethal cardiovascular defects, activating this critical pathway during cell transplantation could improve efficacy of stem cell therapy. Objective: Investigate i) whether self-assembling peptide scaffolds can be used to activate Notch1 signaling in CPCs to promote cardiogenic differentiation and ii) the effect of scaffold stiffness on Notch1 activation and differentiation. Methods: Rat CPCs (c-kit + ) were cultured for 48h in 3D self-assembling scaffolds of varying stiffness (1% low, 2% high): empty scaffolds (RADA), scaffolds modified with peptide mimicking Notch1 ligand, Jagged1 (RJAG), or scaffolds modified with a scrambled peptide (RSCR) and cardiogenic gene expression measured by qRT-PCR. CHO cells expressing Notch1 responsive YFP were also cultured in the above scaffolds for 48h and YFP expression was determined. Results are mean ± SEM with p<0.05 considered significant by one or two-way ANOVA with appropriate post test. Results: In the Notch1 reporter cells, Notch1 activation increased significantly in presence of RJAG (p<0.01) and on increasing scaffold stiffness (p<0.01,n=6) indicating scaffold stiffness-dependent Notch1 activation. Culture of CPCs in RJAG containing 1% scaffolds (low stiffness) significantly increased early endothelial and smooth muscle but not cardiac gene expression while in 2% scaffolds (high stiffness) significantly increased only cardiac and not endothelial or smooth muscle gene expression (p<0.05, n≥4). Conclusions: Taken together, these data show that i) Notch1 activation in 3D is dependent on ligand density and scaffold stiffness and ii) stiffness dependent Notch1 activation differentially regulates cardiogenic gene expression in CPCs. Therefore, delivery of CPCs in JAG containing scaffolds could be used to improve cardiac function following MI.

scholarly journals Enhanced gene expression of Na+/Ca2+exchanger attenuates ischemic and hypoxic contractile dysfunction

2000 ◽  
Vol 279 (6) ◽  
pp. H2846-H2854 ◽  
Author(s):  
Thomas G. Hampton ◽  
Ju-Feng Wang ◽  
Joseph DeAngelis ◽  
Ivo Amende ◽  
Kenneth D. Philipson ◽  
...  
Keyword(s):  
Gene Expression ◽  
Sarcoplasmic Reticulum ◽  
Cardiac Function ◽  
Intracellular Calcium ◽  
Systolic Pressure ◽  
Contractile Dysfunction ◽  
Compensatory Mechanism ◽  
Wild Type ◽  
Generating Capacity ◽  
And Function

Enhanced gene expression of the Na+/Ca2+exchanger in failing hearts may be a compensatory mechanism to promote influx and efflux of Ca2+, despite impairment of the sarcoplasmic reticulum (SR). To explore this, we monitored intracellular calcium (Cai 2+) and cardiac function in mouse hearts engineered to overexpress the Na+/Ca2+ exchanger and subjected to ischemia and hypoxia, conditions known to impair SR Cai 2+transport and contractility. Although baseline Cai 2+and function were similar between transgenic and wild-type hearts, significant differences were observed during ischemia and hypoxia. During early ischemia, Cai 2+ was preserved in transgenic hearts but significantly altered in wild-type hearts. Transgenic hearts maintained 40% of pressure-generating capacity during early ischemia, whereas wild-type hearts maintained only 25% ( P < 0.01). During hypoxia, neither peak nor diastolic Cai 2+ decreased in transgenic hearts. In contrast, both peak and diastolic Cai 2+ decreased significantly in wild-type hearts. The decline of Cai 2+ was abbreviated in hypoxic transgenic hearts but prolonged in wild-type hearts. Peak systolic pressure decreased by nearly 10% in hypoxic transgenic hearts and >25% in wild-type hearts ( P < 0.001). These data demonstrate that enhanced gene expression of the Na+/Ca2+ exchanger preserves Cai 2+ homeostasis during ischemia and hypoxia, thereby preserving cardiac function in the acutely failing heart.

High sugar diet adversely effects gene expression, cardiac function and survival with pressure overload

2007 ◽  
Vol 42 (6) ◽  
pp. S141-S142
Author(s):  
Brian R Barrows ◽  
Naveen Sharma ◽  
Agnes M. Azimzadeh ◽  
Hani Sabbah ◽  
Victor Sharov ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cardiac Function ◽  
Pressure Overload ◽  
High Sugar

scholarly journals Elevated myocardial Na+/H+ exchanger isoform 1 activity elicits gene expression that leads to cardiac hypertrophy

2010 ◽  
Vol 42 (3) ◽  
pp. 374-383 ◽  
Author(s):  
Jin Xue ◽  
Fatima Mraiche ◽  
Dan Zhou ◽  
Morris Karmazyn ◽  
Tatsujiro Oka ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Death ◽  
Cardiac Hypertrophy ◽  
Cardiac Function ◽  
Interstitial Fibrosis ◽  
Gene Activation ◽  
Weight Ratio ◽  
Heart Weight ◽  
Peroxisome Proliferator ◽  
Cross Sectional

In myocardial disease, elevated expression and activity of Na+/H+ exchanger isoform 1 (NHE1) are detrimental. To better understand the involvement of NHE1, transgenic mice with elevated heart-specific NHE1 expression were studied. N-line mice expressed wild-type NHE1, and K-line mice expressed activated NHE1. Cardiac morphology, interstitial fibrosis, and cardiac function were examined by histological staining and echocardiography. Differences in gene expression between the N-line or K-line and nontransgenic littermates were probed with genechip analysis. We found that NHE1 K-line (but not N-line) hearts developed hypertrophy, including elevated heart weight-to-body weight ratio and increased cross-sectional area of the cardiomyocytes, interstitial fibrosis, as well as depressed cardiac function. N-line hearts had modest changes in gene expression (50 upregulations and 99 downregulations, P < 0.05), whereas K-line hearts had a very strong transcriptional response (640 upregulations and 677 downregulations, P < 0.05). In addition, the magnitude of expression alterations was much higher in K-line than N-line mice. The most significant changes in gene expression were involved in cardiac hypertrophy, cardiac necrosis/cell death, and cardiac infarction. Secreted phosphoprotein 1 and its signaling pathways were upregulated while peroxisome proliferator-activated receptor γ signaling was downregulated in K-line mice. Our study shows that expression of activated NHE1 elicits specific pathways of gene activation in the myocardium that lead to cardiac hypertrophy, cell death, and infarction.

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