bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 21: Stiffness-Dependent Notch1 Activation Regulates Cardiogenic Differentiation of Cardiac Progenitor Cells
Authors: Boopathy Archana V , Salaita Khalid , Davis Michael E 
Published: July 2021

Cardiac progenitor cells (CPCs) are multipotent, self-renewing cells that can regenerate the myocardium and improve cardiac function in animal models of MI by cardiogenic differentiation. However, limited survival of stem/progenitor cells, myocardial scarring and fibrosis inhibit cardiac regeneration. Notch signaling promotes early cardiac development, cardiomyocyte survival and cardiac gene expression in circulating endothelial progenitor cells, mesenchymal stem cells and CPCs. As misregulation of Notch signaling during development is lethal due to cardiovascular defects, activating this critical pathway during cell transplantation could improve the efficacy of stem cell therapy. We investigated whether self-assembling peptide nanofiber hydrogels can be used to activate Notch1 signaling.
The 16 amino acid self-assembling scaffold (RAD) was modified with a 20 amino acid peptide mimicking the active site of Notch1 ligand, Jagged1 (RJAG) or with the corresponding scrambled peptide (RSCR). To determine whether scaffold stiffness regulates Notch1 activation, CHO cells with Notch1 responsive YFP expression were cultured in scaffolds of 1-3% w/v in presence of RSCR or RJAG at a 1:10 ligand: scaffold ratio in 3D. Presence of the RJAG peptide (p<0.01) and % concentration of the scaffold (p<0.01) increased Notch1 activation significantly (n=5) indicating that RJAG mediated Notch1 activation in 3D is scaffold stiffness-dependent. Therefore, CPCs were cultured within 3D scaffolds (1-3% w/v; empty, scaffold +RJAG or RSCR) and cardiogenic gene expression was determined by qPCR. An increase in expression of early endothelial (Flk1, Flt1, vWF) and smooth muscle (sm22α, sm αactin) genes was observed in CPCs cultured in 3D scaffolds containing RJAG but not when cultured in 2D. These data show that Notch1 activation is dependent on ligand density and scaffold stiffness. Delivery of CPCs in JAG1 containing self-assembling scaffolds could be used to enhance therapeutic angiogenesis and improve cardiac function following myocardial infarction.
Abstract 213: Rapid Activation of G-Protein Coupled Estrogen Receptor 1 Protects the Heart Against Ischemia-Reperfusion Injury by Inhibiting the mPTP Opening via PKC/AKT/ERK/GSK-3b Pathways
Authors: Bopassa Jean Chrisostome , Lu Rong , Singh Harpreet , Zilberstein Netanel F , Olde Bjorn , Krust Andree , Leeb-Lundberg L M Fredrik , Toro Ligia , Stefani Enrico 
Published: July 2021

Introduction: Estrogen effect can be mediated by three receptors: Classical estrogen receptors: alpha (ERa) and beta (ERb), and recently identified G protein-coupled estrogen receptor1 (GPER1).
Hypothesis: We investigated the role of ERa, ERb and GPER1 in mediating rapid estrogen-induced cardioprotection in male mice hearts subjected to ischemia/reperfusion using wild type (WT) and gene specific knockout animals.
Methods: Isolated hearts from wild type (WT: C57BL/6NCrL), ERa-/-, ERb-/- and GPER1-/- were perfused using Langendorff apparatus with Krebs Henseleit buffer (control) or with the addition of estrogen (40 nM). Hearts were subjected to 18 min global ischemia followed by 60 min reperfusion. Cardiac function was recorded during the entire experiment and myocardial infarct size measured by TTC staining at the end of the reperfusion. Mitochondria calcium retention capacity (CRC) required to induce the mitochondrial permeability transition pore (mPTP) opening was assessed after 10 min reperfusion. Protein levels were measured by Western Blot in whole heart lysates after 5 min treatment just before ischemia, and after 10 min reperfusion. LY294002, U0126 and Chelerythrin-Cl were used as inhibitor of PI-3K/Akt, MAPK/ERK and PKC translocation, respectively.

Results: In WT, ERa-/- and ERb-/-, estrogen treatment significantly improved cardiac functional recovery, reduced infarct size and improved mitochondrial CRC. However, estrogen effects were completely absent in GPER1-/-. Estrogen treatment during 5 min before ischemia induced up-regulation of Akt, GSK-3b, and ERK1/2 phosphorylation in WT mouse as compared with control but not in GPER1-/-. However, after 10 min reperfusion estrogen effect was still oserved on GSK-3b, but not on Akt and ERK1/2. Chelerythrin-Cl prevented estrogen-induced cardioprotection effect and U126 abolished estrogen effect on mitochondrial CRC while
LY294002
could not prevent estrogen effect on GSK-3b observed in WT. P<0.05 and n=3-6.

Conclusion: Rapid activation of GPER1 induces cardioprotection effect against ischemia/reperfusion injury. Estrogen effects through GPER1 are associated with phosphorylation of Akt, GSK-3b and ERK1/2, translocation of PKC, and inhibition of the mPTP opening.
Abstract 288: Atheroprotective Effect of Probucol Is Related to Its Heme Oxygenase 1 Activation and Subsequent Suppression of Oxidized Low-Density Lipoprotein--Induced Dendritic Cell Maturation
Authors: Sun Aijun , Jin Xueting , Zhao Jingjing , Wang Keqiang , Xu Fang , Huang Wei , Liu George , Zou Yunzeng , Hu Kai , Ge Junbo 
Published: July 2021

Aims: Probucol, an agent characterized by lipid-lowering and anti-oxidant property, retards atherosclerosis effectively. Our study aimed to test the hypothesis that probucol might act its anti-athersclerotic role by suppressing maturation of human monocyte-derived dendritic cells (h-monDC). Furthermore, we also used a LDLR-/- mice model fed a high-fat diet to detect whether probucol also perform its anti-atherosclerotic effect on suppressing DCs maturation in vivo.
Methods: H-monDCs were derived by incubating purified human monocytes with GM-CSF and IL-4. H-monDCs were pre-incubated with or without probucol and stimulated by oxidized low-density lipoprotein (ox-LDL) in the presence or absence of heme oxygenase (HO-1) siRNA. In vivo studies, streptozotocin (STZ) induced LDLR-/- mice were fed either a high-fat (HF) diet or added with 0.5% probucol for 4 months. Expression of h-monDC membrane molecules and mice splenic CD11c+DC membrane molecules were analyzed by FACS, cytokines were measured by ELISA and the STAT1/CIITA associated signaling pathway was determined by Western blotting. Mice aortic lesions were observed by En face staining and the expression of CD11c+DCs within atherosclerotic plaques were shown under confocal microscopy.
Results: Ox-LDL promoted h-monDC maturation and TNF-a production; and up-regulated STAT1 701 phosphorylation by activating HO-1 in STAT1/CIITA signaling pathway. These effects were inhibited by probucol. Knocking down HO-1 with specific siRNA blocked these effects of probucol. In LDLR-/- mice fed a high-fat diet, probucol treatment significantly regressed aortic atherosclerotic lesions, suppressed splenic CD11c+DCs maturation and IL-12p70 production; and resulted in absence of CD11c+DCs within atherosclerotic lesions.
Conclusions: Our study indicated that probucol effectively suppressed maturation of h-monDC induced by ox-LDL through HO-1 activation, and retarded atherosclerosis at least partly through inhibiting maturations of CD11c+DCs in LDLR-/- mice.
Abstract 29: Heme Levels Are Increased in the Hearts of Patients with End-Stage Heart Failure
Authors: Khechaduri Arineh , Bayeva Marina , Ardehali Hossein 
Published: July 2021

Introduction: Diseases of iron imbalance can cause cardiomyopathy, as observed in hereditary hemochromatosis or Friedreich’s ataxia. However, the iron status of a failing heart has not been systematically examined.
Results: The iron levels were quantified in ten hearts from human patients with end-stage cardiomyopathy and ten unmatched healthy control hearts. Total cellular and cytosolic non-heme iron levels were significantly reduced in failing hearts; however, there was a 2-fold increase in cytosolic heme levels in heart failure, as measured by the total protoporphyrin IX (PPIX) content. The amount of iron-free PPIX was low and did not differ between the two groups, suggesting that the majority of PPIX is complexed with iron to form heme, and thus our assay accurately estimates heme levels in the heart.
To study the mechanism for the increased heme content in failing hearts, we examined the expression of genes involved in heme and iron homeostasis. Consistent with elevated heme, there was a decrease in the levels of the cellular iron importer (transferrin receptor 1 orTfR1) and the first enzyme in heme synthesis (δ-aminolevulinic acid synthase 1 or ALAS1), both of which are negatively regulated by heme. Other genes involved in heme synthesis, iron incorporation into PPIX, and heme degradation were not affected. However, we noted a significant increase in the mRNA and protein levels of ALAS2 in the failing hearts. ALAS2 is normally expressed in hemoatopoietic cells and displays very low expression in the heart. Its induction in the setting of heart failure provides a possible explanation for increased heme levels.
We then assessed whether increase in ALA and heme in failing hearts is associated with generation of reactive oxygen species (ROS). Addition of exogenous ALA led to a four-fold increase in ROS, while incubation with hemin have doubled ROS levels in these cells, suggesting that augmentation of heme synthesis may exacerbate heart failure by increasing the oxidative stress.
Conclusions: Our results suggest that heme levels are increased in human hearts with end-stage cardiomyopathy, possibly through the induction of ALAS2 expression. The elevated heme levels may exacerbate heart failure by increased production of ROS.
Abstract 065: Cardiac Fibrosis and Heart Failure Caused by DsRed Tetramers Involves the Induction of Tissue Inhibitor of Metalloproteinase-1
Authors: Chen Tsung-Hsien , Liu Shan-Wen , Chen Mei-Ru , Lin Kurt M 
Published: July 2021

Whereas aggregation of intracellular proteins was linked to the initiation of cardiac myopathy, the sequence of participating events, including myocyte apoptosis, autophagy, necrosis and fibrosis as the underlying mechanisms leading to heart failure, was not clear. Green fluorescent protein (GFP) and its derivatives induced cardiac dysfunction in mice when expressed in high quantity; however, the mechanism underlying the aggregation of fluorescent protein leading to heart failure remains unexplored.We created a transgenic mouse with switchable expression of the GFP monomer or the expression of DsRed, a red fluorescent protein (RFP) tetramer that tends to aggregate into a large protein complex. GFP mice were free of cardiac symptoms; in contrast, RFP mice with homozygous DsRed alleles developed myocyte necrosis, carditis, ventricular hypertrophy and fibrosis, left atrium thrombosis, dilated heart failure and death at the age of approximately five months. The hemizygote mice displayed similar symptoms at a later age. The expression of the microtubule-associated protein 1 light chain 3 cleaved isoform II (LC3 II) and transglutaminase 2, and the expression of many myopathy- and fibrosis-related genes were significantly induced in the hearts of two-month-old RFP mice. Together with the findings of increased autophagosomes, lysosomes and dysfunctional mitochondria, these results suggest a marked induction of myocyte autophagy and fibrosis as the main underlying mechanism of heart failure in RFP mice. Interestingly, apoptosis was not elevated in RFP hearts. One of the most up-regulated genes in the early stage RFP heart was the tissue inhibitor of matrix metalloproteinases type 1 (TIMP-1), corroborating the role of TIMP-1 in cardiac remodeling and anti-apoptotic activity. The heart-origin of the morbidity in RFP mice was confirmed by expressing DsRed tetramers specifically in cardiac tissues, and the same phenotypes as in RFP mice were observed.
In summary, in cardiac myocytes under the stress of protein aggregation, strong induction of TIMP-1 and down-regulation of MMP activity may play a significant role in enhancing the synthesis of extracellular matrix, resulting in fibrosis and heart failure.
Abstract 066: MEF2-induced Loss of Sarcomeres is Mediated by an Alternative Splice Variant of DMPK
Authors: Elzenaar Ies , van der Made Inge , Wijnen Wino J , Ehler Elisabeth , De Windt Leon J , Pinto Yigal M , van Oort Ralph J 
Published: July 2021

The pathology of heart failure is characterized by poorly contracting and dilated ventricles. Although this is associated with lengthening of individual cardiomyocytes and loss of sarcomeres, the mechanism underlying these changes in cardiomyocyte structure remains to be elucidated. We have previously identified the transcription factor myocyte enhancer factor-2 (MEF2) as important trigger for adverse cardiomyocyte remodeling. Here, we use microarray analysis and gain- and loss- of function approaches to identify MEF2 target genes involved in structural remodeling of the cardiomyocyte.
Isolated neonatal rat cardiomyocytes infected with adenoviruses expressing MEF2 underwent cellular elongation associated with loss of sarcomeric structure. Microarray analysis revealed myotonic dystrophy protein kinase (DMPK) as MEF2 target gene, which we verified by chromatin immunoprecipitation experiments. siRNA mediated knockdown of DMPK prevented MEF2-induced cardiomyocyte elongation and loss of sarcomeres. Interestingly, RT-PCR analysis of known DMPK splice variants demonstrated a relative increase of the DMPK E isoform in failing mouse hearts. To test the role of this specific splice isoform, we generated adenoviruses expressing DMPK E or a kinase dead mutant DMPK E. Overexpression of wildtype DMPK E, but not of the kinase dead mutant, in cardiomyocytes resulted in severe loss of sarcomeric structure. Moreover, quantitative PCR analysis showed a decrease in mRNA levels for several sarcomeric genes after overexpression of DMPK E. These genes are known targets of the transcription factor serum response factor (SRF) and DMPK is known to phosphorylate SRF. Therefore, we tested the effect of DMPK on SRF activity in luciferase experiments, which demonstrated that DMPK E is an inhibitor of SRF transcriptional activity.
Our data indicate that MEF2 induces loss of sarcomeres, which is mediated by at least one specific splice variant of DMPK. Moreover, increased expression of this DMPK splice variant results in a decrease in sarcomeric gene expression, which possibly involves inhibition of SRF transcriptional activity. Together, these results assign a novel function to MEF2 and DMPK in adverse cardiomyocyte remodeling during heart failure development.
Abstract 114: System’s Biology Approach to Non-Invasive Integrative Analysis of Cardiac Energetics
Authors: Diolez Philippe , Deschodt-Arsac Véronique , Arsac Laurent , dos Santos Pierre , Hocini Mélèze , Jais Pierre , Haissaguerre Michel 
Published: July 2021

Our aim is to propose an inovative non-invasive analysis of heart contraction energetics, to be used for diagnosis and therapeutics follow-up in human heart pathologies. The analysis is based on the combination of non-invasive 31P-NMR and IRM techniques and the analytical background of metabolic modular control analysis (MoCA). Metabolic control analysis’ based approaches have been used by us and others to overcome the complexity of intra-cellular regulations and to describe and quantify controls and regulations in complex systems. We previously demonstrated that MoCA does bring new informations on the interplay between ATP demand and supply in heart contraction energetics.
In the present study, MoCA was applied to beating Langendorff perfused guinea pig heart to describe qualitatively and quantitatively the global action of various inotropic effectors effector modifying (Adrenaline) or not (Levosimendan, a calcium-sensitizer; Frank-Starling effect) cytosolic calcium transients. MoCA allows to describe the relative importance of the different routes within the heart by which the inotropic effects are transmitted. The results show that in the absence of calcium transient changes, an energetic feed-back control occurs at the expense of total energy, like in skeletal muscle, while parallel activation of both supply and demand occurs after adrenaline addition, maintaining energy homeostasis (heart energetic paradigm).
In conclusion, clinical application of System’s biology to the study of contraction energetics in patients may help to the understanding of the links between molecular events in pathologies and whole organ function / dysfunction.
Abstract 132: CD13 and ROR2 Mediated Isoloation of hESC Derived Cardiac Mesoderm
Authors: Brady Bevin , Skelton Rhys J , Elliott David A , Weissman Irving L , Ardehali Reza 
Published: July 2021

The human heart has a limited regenerative capacity and there is an unmet demand for improved therapies for myocardial disease. Human embryonic stem cell (hESC) derived cardiomyocytes have potential to facilitate the development of both cell-based and pharmaceutical treatments. To date many studies have focused on the efficient generation of cardiomyocytes from hESCs. However, its clinical use has been limited by technical challenges, including the inability to isolate a pure population of cardiovascular progenitors capable of robust engraftment and regeneration. To this end, we have attempted to identify surface markers that facilitate isolation of cardiac mesoderm and cardiovascular progenitors from differentiating hESCs.
Lineage-specific reporter hESC lines (MIXL1-GFP and NKX2.5-GFP) were utilized to test prospective isolation of early cardiac progenitors using two novel cell surface markers, CD13 and ROR2. A distinct population of cells co-expressing CD13 and ROR2 was isolated after 3 days of hESC differentiation which exhibited a transcriptional profile similar to primitive streak/mesoderm cells. Gene expression analysis and immunostaining confirmed the enrichment of mesodermal cells and near complete removal of endodermal, ectodermal and undifferentiated cells. To quantify the extent of cardiovascular progenitors generated from CD13/ROR2 expressing cells, an NKX2.5-GFP reporter hESC line was used and the double positive cells were sorted after 3 days and maintained in culture for 14 days. The majority of these cells showed enrichment for cardiovascular cells based on gene and protein expression, phenotype, and transplantation studies. By enabling retrieval of early mesoderm precursors from heterogeneous differentiated hESC populations, we anticipate CD13 and ROR2 should have utility in enriching for subsequent cardiac potential_the necessary first developmental step towards creating purified cardiomyocytes from hESC.
Abstract 142: Modeling Drug-Induced Long QT Syndrome with Patient-Specific Induced Pluripotent Stem Cell-Derived Cardiomyocytes
Authors: Stillitano Francesca , Karakikes Ioannis , Kong Chi-wai , Martinelli Brett , Li Ronald , Hajjar Roger J , Hulot Jean-Sebastien 
Published: July 2021

Long QT syndrome (LQTS) is characterized by prolonged cardiac repolarization time and increased risk of ventricular arrhythmia. LQTS can be either inherited or induced notably after drugs intake. Mutations in genes encoding cardiac ion channels have been reported to underlie inherited LQTS. In contrast, drug-induced LQTS (diLQTS) most frequently arises from altered function of the hERG channel; the risk of developing diLQTS varies largely between subjects and most people who have life-threatening diLQTS have no known genetic risk factors.
We investigated whether the susceptibility to develop diLQTS observed in vivo can be recapitulated in vitro using patient-specific induced pluripotent stem cell (iPSC) technology. We collected skin fibroblasts from ten subjects who developed significant diLQTS after administration of Sotalol and/or Erythromycin. Ten other individuals who displayed no changes in QT interval after administration of the same drugs, were selected. iPSC were generated by retroviral delivery of Oct4, Sox2, Nanog and Klf4 in 17 of the 20 individuals. We report preliminary results obtained from iPSC-derived cardiomyocytes (iPSC-CMs) of two subjects. All experiments were performed in a blinded fashion without knowledge of the associated clinical phenotype. Cardiac differentiation of iPSC resulted in the generation of spontaneously beating embryoid bodies. iPSC-CMs showed positive staining for TNNT2, ACTN2 and Cx43. Gene expression analysis confirmed the expression of NKX2.5, MLC2v, MYH6 and MYH7, and of the relevant KCNH2 gene. The two lines had similar basal electrophysiological properties as assessed by measurements of action potential (AP) by patch-clamp technique and extracellular field potentials (FP) using micro-electrode array (MEA). E4031, a classical HERG blocker, significantly prolonged the FP duration (FPD) in a dose-dependent manner in both lines (EC50: 30.19 and 51.57 respectively). When both Sotalol and Erythromicin were used, FPD was prolonged in one of the two samples in a dose-dependent manner (EC50Sotalol: 100; EC50Erythr: 9.64) while drug response was blunted in the other cell line.
This study suggests that patient-specific iPSC can be used to model the functional abnormalities observed in acquired diLQTS.
Abstract 237: Sex-specific Regulation Of Collagen I And III Expression By 17β-estradiol In Rat Cardiac Fibroblasts: Role Of Estrogen Receptors
Authors: Dworatzek Elke , Mahmoodzadeh Shokoufeh , Kunze Sandra , Regitz-Zagrosek Vera 
Published: July 2021

Clinical and animal studies showed in female pressure-overloaded hearts less cardiac fibrosis and collagen I and III gene expression compared to males, suggesting an inhibitory effect of 17β-Estradiol (E2) on collagens. Therefore we investigated the role of E2 and estrogen receptors (ER) on collagen I and III expression in isolated rat cardiac fibroblasts from both sexes.
Cardiac fibroblasts were isolated from adult male and female Wistar rats, and treated with E2 (10-8M), vehicle, ERα and ERβ-agonist (10-7M) and/or pre-treated with ICI 182,780 (10-5M) for 24h. Cellular localization of ER in cardiac fibroblasts with/without E2 was detected by immunofluorescence staining, and expression of both ER was determined by western blot. Expression of collagen I and III was determined by qRT-PCR and western blot.
E2-treatment led to a nuclear translocation of ERα and ERβ in cardiac fibroblasts, suggesting the functional activity of ER as transcription factors. Furthermore in cardiac fibroblasts from female rats E2 led to a significant down-regulation of collagen I and III gene and protein expression. In contrast there was a significant increase of collagen I and III levels in fibroblasts isolated from male rat hearts by E2. E2-effect could be inhibited by ICI 182, 780 indicating the involvement of ER. In cardiac fibroblasts from female rats, ERα-agonist treatment led to a significant down-regulation of collagen I and III mRNA level, but ERβ-agonist had no effects. In contrast, ERβ-agonist treatment of cardiac fibroblasts from males increased collagen I and III mRNA, but no changes with ERα agonist-treatment were detected. ERα protein levels displayed no sex differences at basal level. After E2-treatment ERα protein was up-regulated in male cells, but decreased in cardiac fibroblasts from females. ERβ protein was higher in female cells compared to males, but the expression was not regulated by E2 in both sexes.
Sex-specific regulation of collagen I and III expression by E2 in cardiac fibroblasts might be responsible for sex-differences in cardiac fibrosis. This might be due to sexually dimorphic ER expression and regulation. Understanding how E2 and ER mediate sex-differences in cardiac remodeling may help to design sex-specific pharmacological interventions.