bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 230: Specific Mitochondrial Adaptation In Chronic Hypoxic Hearts Results In An Improved Intrinsic Energetic Homeostasis
Authors: Deschodt-Arsac Veronique , Calmettes Guillaume , Arsac Laurent , Muller Bernard , Dos Santos Pierre , Hocini Meleze , Jais Pierre , Haissaguerre Michel , Diolez Philippe 
Published: July 2021

Hypoxic states of the cardiovascular system are often associated with severe cardiac diseases. In spite of impairments in contractile activity, mitochondrial content, cell energy status and calcium transients, we recently demonstrated an improved energy homeostasis in chronic hypoxic hearts explained by a higher mitochondrial sensitivity to ATP/PCr changes, based on combined 31P-NMR spectroscopy and the analytical framework of metabolic control analysis.
In the present study, we describe the role of calcium in co-variations in cellular energy status (PCr, ATP) and cardiac work (RPP), in perfused hearts from mice adapted for three weeks to a simulated altitude of 5500 m in a barochamber.
Under basal conditions, lower cardiac work and PCr concentration confirmed energetic impairments in chronic hypoxic hearts. At high calcium concentration, cardiac work increased by 40% both in control and hypoxic hearts while a smaller PCr drop in hypoxic hearts, indicating an improved energy homeostasis and higher mitochondrial sensitivity to PCr changes. Stimulating calcium transients by adrenaline and thereby parallel activation of supply and demand components increased cardiac work twice as much only in control hearts (RPP +100%) without any significant PCr variation. The blunted effect of adrenaline in hypoxic hearts is likely the consequence of attenuated ß1-adrenergic receptors stimulation. Inhibition of mitochondrial calcium uniporter by ruthenium red which abolished the mitochondrial-mediated adrenergic regulation was not effective in chronic hearts in contrast of control.
We conclude that although chronic hypoxic hearts failed to use calcium transients to optimize their inotropic response to a specific adrenergic stimulation, they present specific adaptation of the energetic homeostasis based on improved energy supply sensitivity. Interestingly this better regulation of the energetic system is not explained by a direct effect of calcium on mitochondria but rather by an optimized metabolic feedback.
Abstract 312: STIM1 And The Development Of Pressure-overload Induced Cardiac Hypertrophy In Rodents
Authors: Bénard Ludovic O , Matasic Daniel S , Keck Mathilde , Lompré Anne-Marie , Hajjar Roger J , Hulot Jean-Sébastien 
Published: July 2021

STromal Interaction Molecule 1 (STIM1), a membrane protein of the sarcoplasmic reticulum, has recently been proposed as a positive regulator of cardiomyocyte growth by promoting Ca2+ entry through the plasma membrane and the activation of Ca2+-mediated signaling pathways. We studied the role of STIM1 in a pressure-overload induced cardiac hypertrophy model in mice. We observed that STIM1 cardiac expression is increased during left ventricular hypertrophy (LVH) induced by Transverse Aortic Constriction (TAC). We then used recombinant Associated Adenovirus 9 (AAV9) to perform cardiac-targeted gene silencing in vivo. C57Bl/6 mice were injected with saline (noAAV) or with AAV9 expressing shRNA against STIM1 (shSTIM1) at the dose of 1e+11 viral genome which resulted in 70% decrease of STIM1 cardiac expression compared to control mice. Three weeks later, TAC was performed and mice were studied three other weeks later.
We found that TAC-shSTIM1 treated mice did not develop LVH compared to noAAV despite the same increase in aortic pressure. Echocardiographic and hemodynamic measurements (see table) showed that TAC-shSTIM1-treated mice had LV dilation and a decreased left ventricular contractile function in line with the absence of compensatory LVH in these mice. Immunohistochemistry demonstrated that LVH prevention was observed at the cellular level with cardiac myocytes cross-section area comparable to sham littermates however with a trend towards more interstitial fibrosis.
This study reveals the essential role of STIM1 in the development of compensatory LVH in mice.
Abstract 133: Novel Transgenic Mouse Lines for Identification of Cardiomyocyte Nuclei and Visualization of Their Cell Cycle Status In-vitro and In-vivo
Authors: Raulf Alexandra , Horder Hannes , Geisen Caroline , Grünberg Sabine , Freitag Patricia , Fleischmann Bernd K , Hesse Michael 
Published: July 2021

The typical remodelling process after cardiac injury is scarring and compensatory hypertrophy. The limited regeneration potential of the adult heart is due to the post-mitotic status of cardiomyocytes (CMs), which are mostly binucleated. Nevertheless, there is evidence for CM turnover in the adult heart, but its extent is still under debate. One technical limitation of quantitations is the unequivocal identification of CMs and of CM cell division.
In order to enable a clear identification of CM nuclei in-vivo, we have developed a transgenic mouse line in which a fusion protein of the human histone 2B and the red fluorescence protein mCherry is specifically and persistently expressed in CM nuclei (αMHC-H2B-mCh). The fluorescence label allowed the investigation of CM percentages in native tissue slices, which properly reflect the cellular composition of the heart. We focused on regional (atrium versus left and right ventricle, apical versus basal slices) and developmental-stage dependent changes in the percentage of CM nuclei and binuclearity. We therefore analyzed time-points before/during and after terminal differentiation of CMs (postnatal day 3 (P3), P7 and 9 weeks). In addition, we also investigated endoreduplication and acytokinetic mitosis using time lapse microscopy in postnatal CMs to better understand cell biological mechanisms leading to terminal differentiation.
As currently huge efforts are invested for the search of substances that increase the regeneration potential of the heart, we established a novel screening assay for cell-cycle modifying substances in isolated, postnatal CMs. We crossed the αMHC-H2B-mCh with the CAG-eGFPanillin mouse line, which marks cell-cycle activity with a high resolution of M-phase. Analysis of binuclearity and of different eGFPanillin subcellular localizations will be helpful to understand, whether CMs complete cytokinesis. As a proof of principle we investigated the effects of cell cycle activating micro RNAs199 and 590.
Thus, our double transgenic mouse line will be useful to examine the plasticity of mono- and binuclear CMs and to unravel cell biological mechanisms leading to terminal differentiation of CMs.
Abstract 145: Mitophagy Protects Against Statin-Induced Cell Death in Muscle Cells
Authors: Andres Allen , Ramesh Mridula , Hernandez Genaro , Gurney Michael , Linton Phyllis-Jean , Islam Moutusee , Gottlieb Roberta 
Published: July 2021

Statins are a family of cholesterol lowering drugs associated with undisputable cardiovascular benefits. However, their use is associated with the risk of developing skeletal muscle myopathy which remains a significant barrier to maximizing the efficacy of statin therapy. Many recognize that the instances of statin-associated myopathy reported grossly underestimate the actual frequency of these events. Statin myopathy is a major reason for why many patients are unable to comply with their prescribed statin treatments. Identifying and understanding the molecular events involved in the development of statin-induced myopathy will pave the way to mitigating the unwanted effect of statin-myopathy.
We have identified that statins induce mitochondrial loss in both C2C12 myotubes, and in gastrocnemius muscle of mice evidenced by loss of mitochondrial markers Tom70 and Cox4 by western blot analysis. C2C12 myotubes were treated with 2μM simvastatin for 24 hours, and wild-type C57BL/6 mice were given a daily i.p. dose of 20mg/kg simvastatin for 2 weeks. Pretreatment of C2C12 cells with 100nM bafilomycin for 2 hours before statin treatment attenuated autophagic flux, and prevents the observed loss of mitochondria through Tom70 and Cox4 mitochondrial markers. Thus, the loss of mitochondria is attributable to autophagy (mitophagy). Statin treatment increases the expression of Bnip3 and p62/SQSTM1 (sequestosome 1) which have been identified as important facilitators of mitophagy. We found increased Bnip3 dimerization via western blot under non-reducing conditions which implies increased activity. Furthermore, we observed increased mitochondrial translocation of p62/SQSTM1. Based on our findings, we hypothesized that statin-induced mitophagy may play a key role in the development of muscle myopathy.
To investigate the role of mitophagy in statin myopathy, we silenced p62/SQSTM1 via RNAi prior to statin treatment. Surprisingly, reducing mitophagic flux via p62/SQSTM1 silencing resulted in increased destruction of myotubes. This was associated with increased levels of cytosolic cytochrome c. Our data combined suggests that mitophagy protects against statin-mediated cell death by sequestering and eliminating decrepit mitochondria via autophagy.
Abstract 216: Traditional Chinese Medicine Tongxinluo Modulates The Secretion Of Cytokines In Vitro By Cardiac Microvascular Endothelial Cells In Ischemia/Reperfusion Injury.
Authors: Cui Hehe , Li Xiangdong , Wang Zhigang , Li Na , Qi Kang , Li Qing , Jin Chen , Yang Yuejin 
Published: July 2021

Cardiac microvascular endothelial cells (CMECs) regulate the function of cardiomyocytes and blood cells in myocardial ischemia/ reperfusion injury (MIRI) via paracrine methods. Tongxinluo (TXL) is a Traditional Chinese Medicine compound to treat angina pectoris in China, which is constituted of ginseng and other 11 natural products. It is proved to improve the endothelial function and be protective against MIRI. Thus, we aimed to find alterations in paracrine function of CMECs under the hypoxia/reoxygenation (H/R) situation and its modulation by TXL.
CMECs were exposed to different concentrations of TXL for 30 min and then subjected to H/R for 12 h/2 h. Apoptotic rates were measured to determine the optimal concentration. Protein antibody arrays were used to find the alterations of cytokines in conditioned medium (CM) secreted by CMECs. Gene Ontology project was adopted to describe the functions of changed cytokines.
TXL inhibited apoptosis of CMECs dose-dependently under H/R and reached its peak effect at 800 μg/mL. Thirty-three types of cytokines were significantly changed by H/R (19 factors decreased and 14 increased), and TXL at 800μg/ml changed 121 types of cytokines compared to the H/R group (93 factors decreased and 28 increased). The cytokines with significant alterations were involved in cell differentiation and proliferation, positive chemotaxis, and endothelial cell migration. Among these cytokines, bFGF, PDGF and IL-7 were attenuated by H/R and further decreased by TXL, while IL-21, MCP-2 and GROa were increased by H/R but decreased by TXL.
The study elucidated the paracrine function of CMECs in MIRI and partly illuminated the protective mechanisms of TXL.
Abstract 311: Inhibition Of Matrix Metalloproteinase-13 Dependent Protease-activated Receptor-1 Activation Attenuates Fibrotic Signaling
Authors: Dixon Allison E , Jaffre Fabrice , Mackman Nigel , Blaxall Burns C 
Published: July 2021

Heart failure (HF) is the leading cause of morbidity and mortality in the United States and is characterized by progressive myocardial fibrosis, pathologic remodeling and deteriorating cardiac function. Cardiac fibroblasts (CF) are largely responsible for the secretion of ECM proteins as well as cytokines and growth factors in the heart. Upon injury or pathologic stimulation, CF transition to a myofibroblast phenotype, leading to excess production of ECM proteins and pro-inflammatory cytokines. Previous studies in our lab have indicated a role for protease-activated receptor-1 (PAR-1), the most highly expressed GPCR on CF, in pathologic cardiac remodeling. In particular, we reported the novel cleavage of PAR-1 via matrix metalloproteinase-13 (MMP-13) and cardioprotective effects of MMP-13 inhibition in an acute model of HF. Therefore, we hypothesize that MMP-13 plays an important role in cardiac remodeling through activation of PAR-1, particularly in the pathologic transition of CF to myofibroblasts.
To investigate this hypothesis, RNA was collected from hearts of mice infused with isoproterenol (ISO) for 7 days and concurrently treated with a specific MMP-13 inhibitor, WAY170523, or vehicle. To evaluate the effect of WAY170523, we used qRT-PCR to measure changes in the expression of fibrotic markers, COL1a1, COL3a1, and TGF-β. Inhibition of MMP-13 with WAY170523 attenuated expression of these genes compared to vehicle treated animals.
We previously reported that stimulation of CF and cardiomyocytes with MMP-13 induces phosphorylation of ERK1/2, a member of the MAPK family known to play a role in cardiac hypertrophy, and treatment with a direct PAR-1 antagonist decreased the activation of ERK1/2. We have found that ERK1/2 phosphorylation is directly attenuated following inhibition of MMP-13 with WAY170523.
Overall, these data suggest a role for MMP-13 dependent PAR-1 activation in pathologic myofibroblast transition and a potential therapeutic role for MMP-13 inhibition, possibly through its inhibition of ERK1/2 phosphorylation. Treatment with WAY170523 also attenuates markers of fibrosis in vivo, indicating a potential salutary role for MMP-13 inhibition in the treatment of HF.
Abstract 325: Dissociation of Oxidative Stress from High Fatty Acid-Induced Cardiac Myocyte Death
Authors: Gutierrez Cortes Nicolas , Zhang Huiliang , Xu Shangcheng , Gong Guohua , Wang Wang 
Published: July 2021

Metabolic syndrome, featured by obesity and diabetes, is an independent risk factor for cardiovascular disease. The high availability of free fatty acids characteristic of obesity has been proposed to increase fatty acid oxidation, impair mitochondrial function, stimulate reactive oxygen species (ROS) production and eventually lead to oxidative stress, which then would cause myocyte damage and heart dysfunction. However, the role of oxidative stress as the initial cause of obesity-induced heart failure is controversial.
We evaluated the time-dependent effect of fatty acids in vitro in adult rat cardiac myocytes (treated with palmitate and oleate, the major saturated and unsaturated fatty acids in the plasma, respectively), and in vivo in mice fed a high-fat diet (fat calories = 60%).
Palmitate and oleate dose-dependently stimulated mitochondrial respiration and superoxide flash activity, a respiration-coupled bursting ROS production event in single mitochondria. The flash frequency increased 2-fold (0.1 mM, the physiological level in plasma) and 3-fold (0.3 mM, the plasma level found in obese subjects) after only 2 hr incubation and up to 24 hr, increase that could be blocked by the CPT1 inhibitor etomoxir (100uM). Surprisingly, there was no obvious mitochondrial oxidative stress, although the high level of fatty acids caused mPTP opening and cell death at 48 hr. Further, aconitase activity was normal and NAD/NADH ratio was decreased, indicating a more reduced status rather than oxidative stress. Intriguingly, mitochondrial membrane potential was slightly lowered after only 2 hr of treatment. Finally, the high-fat diet-fed mice developed heart dysfunction after 12 weeks of treatment, but oxidative stress only appeared after 18 weeks.
In the light of these results, we hypothesize that high fatty acid supply induced multiple adaptive and mal-adaptive responses in cardiac myocytes. The increased mitochondrial respiration and bursting ROS production is offset by a mild uncoupling and increased reducing equivalents. Therefore, oxidative stress is unlikely an initial cause of myocyte death and heart dysfunction in obesity, but rather a consequence of mitochondrial dysfunction, although the exact cause of this dysfunction remains to be elucidated.
Abstract 63: Potential Genetic and Pharmacological Protection from Virus-induced Ventricular Arrhythmias and Sudden Cardiac Death
Authors: Strutz-eebohm Nathalie , Steinke Katja , Henrion Ulrike , Rohbeck Matthias , Klingel Karin , Seebohm Guiscard 
Published: July 2021

In patients as well as in mouse models, enteroviral infections, especially Coxsackie group B viruses (CVB1-6), frequently induce ventricular arrhythmias and sudden cardiac death. The cardiac action potential requires proper function of cardiac ion channels. CVB3 alters Kv7.1 channel trafficking potentially leading to changes in action potentials and increasing likelihood of arrhythmias. Genetic variants of cardiac ion channels can cause changes in channel trafficking that may preserve from CVB3 modulations and present an evolutionary advantage. Here, we show that a common polymorphic Kv7.1 channel variant uses alternative trafficking pathways and may thus exert a benefit during CVB3 infections. Genetic and pharmacological disruption of a CVB3-stimulated Serum- and Glucocorticoid inducible Kinase 1 (SGK1) pathways blunts Kv7.1 channel dysfunctions.
Our results suggest that escape from CVB3-induced SGK1-stimulation by genetic variation in Kv7.1 may be protective and inhibition of SGK1 may present a pharmacological approach to reduce the pro-arrhythmic risk associated with acute coxsackievirus infections.
Abstract 128: Network-based Approaches to Identify Novel Regulators of Heart Failure
Authors: Rau Christoph D , Romay Milagros C , Wang Jessica , Ren Shuxun , Wang Yibin , Lusis Aldons J 
Published: July 2021

Heart failure is a highly heterogeneous disorder characterized by the interactions of multiple environmental and genetic factors. While reductionistic approaches have made significant inroads into characterizing the pathophysiology of the syndrome, they are unable to properly dissect the complex interactions between sets of genes and pathways which result in the emergent phenotypes . Systems genetics offers a means by which these interactions may be identified and explored. We have developed a resource, the Hybrid Mouse Diversity Panel (HMDP) to perform systems-level analyses in mice. Nine week old female mice from 93 unique inbred lines of the HMDP were give 30 ug/g/day of isoproterenol through an abdominally implanted Alzet micropump. After three weeks, mice were sacrificed along with age-matched controls. A portion of the left ventricle was arrayed on an Illumina Mouse Ref 8.0 platform.
Maximal Information Component Analysis was used to construct gene networks, and a module of 41 genes was identified which shows strong correlation to a number of important phenotypic traits, including heart weight and cardiac fibrosis. This module contains a number of genes of interest, including Lgals3, a diagnostic marker for heart failure. Through the use of structural equation modeling, we identified several key genes within the module for further analysis, the most important of which is the metalloprotease Adamts2.
We have performed a series of in vitro analyses demonstrating the important role of Adamts2 in this module using neonatal rat ventricular myocytes. Knockout of Adamts2 results in an amelioration of the hypertrophic response to catecholamine stimulation as well as a reduction of hypertrophic markers such as Nppa and Nppb. Furthermore, we observe that other genes in the module no longer respond to catecholamine stimulation after knockdown of Adamts2.
Abstract 151: Cell-based Therapies for Heart Failure: Changes in Cytokine Expression From Mesenchymal Stem Cells and Induced Pluripotent Stem Cell Derived Cardiomyocytes
Authors: Pandey Amitabh C , Lancaster Jordan , Harris David , Goldman Steven , Juneman Elizabeth 
Published: July 2021

Mesenchymal stem cells (MSCs) use paracrine signaling to modulate the cellular microenvironment via expression of cytokines, chemokines, and adhesion molecules to aid and promote endogenous repair. Induced pluripotent stem cell derived cardiomyocyte (iPSC-CMs) and mesenchymal stem cells (MSCs) together may play a synergistic role in changing the microenvironment milieu to allow for endogenous cellular repair through paracrine signaling. Cytokine expression is involved in the progression of heart failure (HF). Using a rat model of HF, cell based therapies with a fibroblast embedded patch only, iPSC-CM patch, and MSCs via tail vein (IV) or intracardiac injections (IC) to the left ventricle (LV) were administered, and RNA was subsequently isolated, and real-time polymerase chain reaction (PCR) was performed for analysis of gene expression.
Evaluation of gene expression revealed significant increases in the expression of connexin 43 with iPSC-CMs (p<0.05). Expression of MMP9 was decreased with MSCs alone (p<0.05) but with the use of the patch with both cell types, its levels were significantly increased (p<0.05). Myosin heavy chain was seen to increase significantly with increasing cell numbers in iPSC-CM therapy (p<0.05). Markers of angiogenesis including vascular endothelial growth factor, angiopoietin, and insulin like growth factor were significantly increased with iPSC-CM patch therapy (p<0.05). Up-regulation of angiogenic cytokines and cardio-protective cytokines may help in slowing progression of HF. Interestingly, we also observed an increase in some markers, which were associated with HF. In conclusion, both iPSC-CM patch and MSCs altered signaling in the setting of HF, perhaps leading to improvement of at the cellular level. An iPSC-CM-based patch and MSCs as an adjuvant therapy may be able to play a role in the setting of HF as cellular therapeutic approach.
Abstract 193: RNA-sequencing of Disease-specific iPSC as a New Filter to Identify Genes Associated With Hypoplastic Left Heart Syndrome
Authors: Martinez Fernandez Almudena , Li Xing , Theis Jeanne L , Terzic Andre , Olson Timothy M , Nelson Timothy J 
Published: July 2021

Hypoplastic Left Heart Syndrome (HLHS) is a complex multifactorial disease for which no definitive genetic causes have been found. Current genetic filtering strategies render lists of genes with unknown relevance in terms of pathogenesis. A complementary filter based on biological evidence would create a new approach to prioritize relevant candidate genes and mutations.

In our study, 5 members of a nuclear family including a child with HLHS were evaluated using echocardiography and their genetic information was obtained through whole genome sequencing (WGS). Data filtering including rarity, functional impact and mode of inheritance was implemented, resulting in identification of 34 genes with recessive or
de novo
variants potentially involved in the pathogenesis of HLHS.

Additionally, iPSC were derived from proband and parents and subjected to RNA-sequencing at the undifferentiated state and following spontaneous differentiation. Comparative transcriptional analyses identified genes differentially expressed in proband samples at each stage. These gene sets were used as an additional filter for the previously generated WGS data. This strategy revealed that out of 34 mutated genes originally identified, 10 displayed transcriptional differences in undifferentiated iPSC from the HLHS-affected individual while 16 out of 34 mutated genes showed significantly different expression levels in differentiated cells from proband. Furthermore, expression dynamics were studied during guided cardiac differentiation for the 9 genes fulfilling all applied criteria. Two genes not previously linked to HLHS, ELF4 and HSPG2 were found to behave significantly different in HLHS-iPSC when compared to control counterparts.
In summary, filtering WGS data according to a new layer of transcriptional information that leverages iPSC plasticity allows prioritization of genes associated with HLHS in an in vitro model of disease.