bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 887: Activation of Autophagic Flux Rescues Mitochondrial Homeostasis During Cardiac Ischemia/Reperfusion Injury
Authors: Yang Jing , Cho Geoffrey W , He Jin , Zeng Xiachang , Ebner Kaeli , Ballinger Scott , Young Martin , Prabhu Sumanth , Zhang Jianyi , Hill Joseph A , Xie Min
Published: October 2019

Objective:
Reperfusion injury accounts for ~50% of myocardial infarct size, and meaningful clinical therapies targeting this do not exist. We have shown that HDAC inhibition-enhanced cardiomyocyte autophagy blunts ischemia/reperfusion (I/R) injury given at the time of reperfusion. However, as HDAC inhibition may have off-target effects, we set out to test whether augmentation of autophagy protects myocardium through maintenance of mitochondrial homeostasis and reduction of oxidative stress during reperfusion injury.

Methods:
10-week-old, wild-type, C57BL6 mice were randomized into 3 groups: vehicle control, or exposed to a Tat-Scrambled (TS) peptide, or a Tat-Beclin (TB, autophagy-inducing molecule) peptide. Each group was subjected to I/R surgery (45min coronary ligation, 24h reperfusion). Infarct size, systolic function, and mitochondrial dynamics were assayed. Cultured neonatal rat ventricular myocytes (NRVMs) were exposed to TB during simulated ischemia/reperfusion injury. ATG7 knockout (ATG7 KO) mice and ATG7 knockdown by siRNA in NRVMs was used to evaluate the role of autophagy.

Results:
TB treatment at reperfusion reduced infarct size by 20.1% (n=23, p<0.05) and improved systolic function (n=11, p<0.05). Improvement correlated with increased autophagic flux in the border zone with less oxidative stress. ATG7 KO mice did not manifest TB-promoted cardioprotection during I/R. TB increased mtDNA content in the border zone (n=10, p<0.05). In NRVMs subjected to I/R, TB reduced cell death by 41% (n=12, p<0.001), reduced I/R-induced mtDNA damage, and increased mtDNA content by >60% (n=3, p<0.05). Moreover, TB promoted expression of the gene coding for PGC-1α, which controls mitochondrial biogenesis, in the border zone (n=10, p<0.05) and in NRVMs subjected to I/R (n=3, p<0.05), along with expression of the mitochondrial dynamics genes
Drp1, Fis1
and
MFN1
/
2
(n=9, p<0.05). Conversely, ATG7 knockdown in NRVMs abolished these beneficent effects of TB on mitochondria.

Conclusions:
Autophagy is a sufficient and essential process to mitigate reperfusion injury through maintenance of mitochondrial homeostasis. Augmentation of autophagic flux may emerge as a viable clinical therapy to reduce reperfusion injury in myocardial infarction
Abstract 902: Leveraging Natural Cardiomyocyte Variability to Investigate Downregulation of β-1 Adrenoceptors Following Dobutamine Treatment
Authors: Clark J. Alexander , Weiss Jonathan , Campbell Stuart
Published: October 2019

In heart failure, the most consistent effect on the myocardial beta-adrenergic pathway is a downregulation of β-1 adrenoceptors (β1AR). This loss of receptors impairs the ability of the heart to respond to increases in cardiac demand, and can lead to decreased myocyte function even at rest. As a model of the process that leads to downregulation of β1AR, we measured intracellular Ca
2+
transients and unloaded sarcomere shortening in electrically stimulated isolated adult rat cardiomyocytes undergoing 30 minutes of exposure to 40 nM dobutamine. These experiments were facilitated by a custom device containing micro-patterned wells that orient and immobilize the cardiomyocytes, allowing for rapid and consistent measurements over an extended time period. After functional measurements, cells are picked up individually with a computerized micro-aspirator and subjected to single-cell RT-qPCR to quantify abundance of transcripts of interest. In this way, the physiological responses of individual cells to β1AR stimulus can be correlated to gene expression levels. We found a surprising diversity in the single-cell responses to dobutamine exposure. Although average cardiomyocyte contractility increased significantly, several apparently healthy cells registered no change or even a decrease in sarcomere shortening in the presence of dobutamine. Gene expression was quantified in cardiomyocytes representing a spectrum of sensitivities to dobutamine (n = 7). The transcript for β1AR was significantly downregulated in all cells after 30 minutes, indicating consistent adaptation to chronic stimulus. However, abundance of the gene encoding PKA was negatively correlated with dobutamine-triggered augmentation of Ca
2+
release (p-value: 0.0201). In other words, PKA expression was reduced in cells that experienced potent increases in Ca
2+
release after dobutamine treatment. These data suggest the presence of gene regulatory circuits that modulate individual components of the β1AR pathway independent of overall β1AR abundance. These circuits may be critical to restoring β1AR sensitivity in the failing heart.
Abstract 903: Rapamycin Treatment Reduces Myocardial Stiffness and Promotes Cardiomyocyte Relaxation to Restore Diastolic Function in Old Murine Hearts
Authors: Chiao Ying Ann , Kooiker Kristi , Cheng Yuanhua , Powers Joe , Razumova Maria , Granzier Henk , Regnier Michael , Rabinovitch Peter , Moussavi-Harami Farid
Published: October 2019

Aging is associated with a decline in diastolic function and is a strong risk factor for heart failure with preserved ejection fraction (HFpEF), which has no effective treatment. We previously showed that late-life rapamycin treatment can reverse age-related cardiac dysfunction in mice. However, the mechanisms of the reversal of diastolic dysfunction have not been established. The objective of this study is to determine the mechanisms by which rapamycin reverses age-related diastolic dysfunction.

To study the effects of rapamycin on myocardial stiffness, we assessed the passive length-tension relationship of demembranated trabecular muscle from young, old control and old rapamycin-treated mice. We observed a substantial increase in the slope of the length-tension curve with aging, indicating an age-related increase in myocardial stiffness. The age-related increase in myocardial stiffness was significantly reduced by rapamycin treatment, by a mechanism independent of titin isoform shift. We measured the force-calcium relationship of the demembranated trabeculae and revealed an age-related increase in Ca
2+
sensitivity, as indicated by a left-shift of the force-pCa curve, which was partially restored after rapamycin treatment (pCa50: 5.59±0.04 for young controls; 5.76±0.04 for old controls; and 5.65±0.04 for old rapamycin-treated group). To investigate the changes at myofibril level, we assessed kinetic properties of control and rapamycin-treated myofibrils following maximal (pCa 4.0) and submaximal (pCa 5.6) Ca
2+
activation. Myofibrils from rapamycin-treated mice displayed increased rate of the fast phase of relaxation (kREL, fast) compared to old control at both maximal and submaximal Ca
2+
levels, potentially due to reduced myofibril Ca
2+
sensitivity. Studies have detected age-related reductions in expression and activity of SERCA2, which is responsible for SR calcium reuptake during diastole. In this study, we showed that rapamycin increased SERCA2 expression, which may improve cardiomyocyte relaxation.

In summary, our results suggest that rapamycin normalizes age-related increases in myocardial stiffness and Ca
2+
sensitivity and improves myofibril relaxation kinetics, therefore, improving diastolic function.
Abstract 908: Mechanism of Calcium Sensitivity Modulation of Cardiac Troponin C by Small Molecules Illuminated by Umbrella Sampling Simulations
Authors: Lindert Steffen
Published: October 2019

Cardiac troponin C (cTnC) binds intracellular calcium and subsequently cardiac troponin I (cTnI), initiating cardiac muscle contraction. Due to its role in contraction, cTnC has been a therapeutic target in the search for small molecules to treat cardiomyopathies that interfere with normal muscle contraction. Structural studies have shown the binding location of small molecules such as bepridil, dfbp-o, 3-methyldiphenylamine (DPA) and W7 to be a hydrophobic pocket in the regulatory domain of cTnC (cNTnC) but have not shown the influence of these small molecules on the dynamics of opening this domain. Here we describe an application of an umbrella sampling method used to elucidate the impact these calcium sensitivity modulators have on the free energy of cNTnC hydrophobic patch opening. We found that all these molecules lowered the free energy of opening in the absence of the cTnI, with bepridil facilitating the least endergonic transformation. In the presence of cTnI, however, we saw a stabilization of the open configuration due to DPA and dfbp-o binding, and a destabilization of the open configuration imparted by bepridil and W7. Predicted poor binding molecule NSC34337 left the hydrophobic immediately in conventional MD simulations suggesting that only hydrophobic patch binders stabilized the open conformation. Additionally, differences in the free energy of hydrophobic patch opening of hypertrophic (HCM) and dilated cardiomyopathy (DCM) cTnC systems were investigated. Molecular dynamics and umbrella sampling simulations revealed a lower free energy of opening for the HCM mutations A8V and A31S, as well as the calcium-sensitizing mutation L48Q. The DCM mutations, Y5H, Q50R, and E59D/D75Y, all exhibited a higher free energy of opening. In conclusion, our developed simulation protocol presents a novel approach to study calcium sensitivity modulation by small molecules and mutations and facilitates a molecular understanding of cardiac muscle contraction.
Abstract 909: Determining the Role of the Co-chaperone BAG3 at the Cardiac Myofilament
Authors: Martin Thomas G , Myers Valerie , Willis Monte , Feldman Arthur , Kirk Jonathan A
Published: October 2019

Bcl-2-associated athanogene 3 (BAG3) is an adaptor protein often associated with protein quality control. In the heart, decreased BAG3 expression is linked to dilated cardiomyopathy. Mutations to BAG3 can result in myofibrillar disarray, indicating a possible role at the sarcomere. One previous study found BAG3 has a role in maintaining sarcomere structure, however this was in neonatal myocytes. Whether BAG3 has any role in the myofilament of the adult myocyte is unknown. To determine if BAG3 is present in the cardiac sarcomere and identify the myofilament-BAG3 interactome, we used co-immunoprecipitation of the myofilament fraction from mouse LV and mass spectrometry. This revealed a robust interaction of BAG3 with the myofilament. Furthermore, BAG3 interacted with a heat shock protein (HSPB8) known to assist in the removal of protein aggregates, which are abundant after MI. To determine the mechanistic role of BAG3, we overexpressed the protein in mice hearts using adeno-associated virus 9. At baseline, overexpression caused a slight decrease in skinned myocyte calcium sensitivity compared to WT. This effect may be due to BAG3’s interaction with β-adrenergic receptors, which can cause PKA phosphorylation of thin filament proteins known to reduce calcium sensitivity. Preliminary data support this. We then exposed these mice to left anterior descending coronary artery ligation to induce MI. Compared to shams, MI decreased maximum calcium activated force (F
max
) in the WT mice, but BAG3 overexpression restored F
max
to near sham levels. We also studied the functional impact of a known disease-causing mutation discovered in humans, P209L. Transgenic overexpression of P209L BAG3 had no effect on F
max
, calcium sensitivity, or cooperativity, suggesting the mutation may not interfere with domains in BAG3 required for its myofilament role. This work is the first to show a functional role for BAG3 in the adult myofilament. However, our findings reveal a complex interaction in which the effect of altered BAG3 expression varies with context. The P209L mutation findings suggest that not all BAG3 mutations have shared phenotypes, a conclusion supported by recent clinical work. Further research is necessary to understand BAG3’s myofilament role in health and disease.
Abstract 918: Pre-B-cell Leukemia Homeobox Interacting Protein 1 is a Novel Regulator of Growth Signaling in the Heart
Authors: Grimes Kelly M , Pyo Anna , Molkentin Jeffery D
Published: October 2019

The cellular mechanisms that allow for cardiomyocyte growth in different directions may yield important information about the development of hypertrophic and dilated cardiomyopathies, diseases which include the widening and lengthening growth of cardiomyocytes, respectively. We have previously found that genetic manipulations of the mitogen-activated protein kinase kinase 1 (MEK1) and extracellular signal-related kinase 1/2 (ERK1/2) signaling pathway cause cardiac hypertrophy and cardiomyocyte widening when the pathway is activated or dilated cardiomyopathy and cardiomyocyte lengthening when it is inhibited. The downstream effectors of the directional growth response controlled by these kinases have yet to be studied. Therefore, an unbiased phosphoproteomic screen was conducted on cardiomyocytes subjected to activation or inhibition of MEK1-ERK1/2 signaling. After validation of the screening hits with western and Phos-tag blots, Pre-B-cell leukemia homeobox interacting protein 1 (PBXIP1) emerged as an interesting target. Although it is known as a microtubule binding protein and regulator of proliferation in cancer cells, its function has never before been studied in the heart. Inhibition of MEK1-ERK1/2 increases phosphorylation of PBXIP1. However, activation of the pathway increases PBXIP1 protein expression, and as such we sought to determine the effects of PBXIP1 overexpression in the heart via adeno-associated virus 9 (AAV9) treatment. At four months of age, mice overexpressing PBXIP1 have significantly larger hearts than controls without a change in cardiac contractility. Intriguingly, histological analysis showed that cardiomyocytes highly infected with PBXIP1 AAV9 are significantly smaller in size compared to uninfected cells. Current studies are manipulating the PBXIP1 phosphorylation sites identified in the phosphoproteomic screen to determine the exact roles they may play in the cardiac growth response.
Abstract 919: Intercalated Disk Protein Xin-beta is Required for the Hippo/YAP Signaling in the Heart
Authors: Guo Haipeng , Lu Yao Wei , Lin Zhiqiang , Huang Zhanpeng , Liu Jianming , Hu Xiaoyun , Wang Yi , Fernandes Tiago , Guo Yuxuan , Lin Jenny L.-C , Lin Jim J.-C , Naya Francisco , Pu William T , Wang Da-Zhi
Published: October 2019

Cardiovascular diseases continue to be a leading cause of death and disability. Despite this alarming fact, there is lack of effectual treatment and the molecular mechanisms underlying these devastating diseases remain elusive. Intercalated disk (ICD) is not only essential for the integrity of cardiomyocytes to withstand the strong mechanical forces imposed by constant heart beating; it is also critical for the dissemination of the electrical signal that initiates cardiac contraction. However, relatively less is known about how ICD transmits pathophysiological signals in cardiomyocytes to modulate gene expression and cardiac function. The Xin-α and Xin-β, belongs to a family of Xin-repeat containing proteins, are primarily located at the ICD of adult cardiomyocytes. They play an important role during heart development. Interestingly, the human homologue of the mouse Xin-β gene was mapped to a locus associated with cardiomyopathy; most importantly, mutations in Xin-α and Xin-β have been found in patients with cardiomyopathy, underscoring the importance of Xin genes to cardiac disease. Our previous studies have shown that Xin-β KO mice die postnatally with severe cardiomyopathy. Here, we report that loss of Xin-β results in defect in cardiomyocyte proliferation. Unbiased transcriptome analyses reveal that gene program related to the Hippo/Yap pathway is altered, leading to the hypothesis that Xin-β regulates cardiomyocyte proliferation and cardiac function by modulating the Hippo/Yap signaling. We identify physical and genetic interaction between Xin-β and components of the Hippo/Yap pathway. We further show that the expression of Xin-β is transcriptionally regulated by Mef2a, Yap and Tead1, suggesting the presence of a Xin-β/Yap feedback regulatory network in the heart. Strikingly, cardiac-specific overexpression of Yap markedly rescues cardiac defects in Xin-β KO mice; indicating a functional and genetic interaction between Xin-β and Yap. Together, our study reveals a novel molecular mechanism by which the ICD protein Xin-β modulates important pathophysiological Hippo/Yap signals to control heart development and cardiac function. Molecules uncovered here will become candidate targets for therapeutic treatment of cardiac disease.
Abstract 921: Carvacrol Protects Against Diabetes-induced Hypercontractility in the Aorta Through Activating Pi3k/akt Pathway
Authors: Liu Yun , Ma Kai-Ting , Wei Jie , Mai Yun-Pei , Qiu Xiao-Xia , Wei Han , Hou Ning , Luo Jian-Dong
Published: October 2019

Vascular complications induced by diabetes constitute the principal cause of morbidity and mortality in diabetic patients. It’s reported that carvacrol (CAR) possess a wide range of biological activities. The effect of CAR on diabetes-induced vasculopathy remains unknown. In this study, diabetic mice were created by intraperitoneal injection of streptozotocin to investigate whether CAR provided a protective effect against diabetes-induced vasculopathy and the underlying mechanisms. We found that CAR decreased blood glucose level of diabetic mice. Moreover, CAR ameliorated diabetes-induced aorta morphological alteration, evidenced by increased thickness of intima-media width and increased number of vascular smooth muscle cell (VSMC) layer. Further studies revealed that CAR inhibited the hypercontractility in the aorta of diabetic mice and VSMC in response to hyperglycemia, evidenced by decreased expression of smooth muscle (SM)-α-actin, and increased expression of Ki67 and PCNA. Furthermore, PI3K/Akt signal pathway was inhibited in the aorta of diabetic mice and VSMC in response to hyperglycemia, while CAR treatment activated PI3K/Akt signaling pathway. In conclusion, our results strongly suggested that CAR played a protective role in diabetes-induced aorta hypercontractility, possibly by activating PI3K/Akt signaling pathway. CAR is a potential drug for the treatment of diabetic vasculopathy.
Abstract 922: Cardiac-specific Deletion of Orai3 Channel Causes Dilated Cardiomyopathy
Authors: Mancarella Salvatore , Kamatham Samuel
Published: October 2019

Background:
Calcium (Ca2+) signalling is a vital regulator of cardiac myocyte function. Defective cellular calcium handling is widely recognized as a significant patho-physiological event in the contractile dysfunction of the failing heart. Orai3 is a newly discovered calcium channels that participate in the voltage-independent calcium currents in the mycardium. However, its role in the heart remain uncharacterized.

Methods and Results:
Here, we show that disruption of Orai3 function in murine cardiomyocytes leads to decompensated dilated cardiomyopathy. Echocardiographic analysis supported by histological examinations revealed that 4-month-old Orai3 knockout (KO) mice have signs of dilated cardiomyopathy denoted by a loss of EF and a thinner left ventricular posterior wall and septum, with significant fibrosis, whereas in the younger animals only a thinner septum could be observed. In both genders, most mice died within six months after birth. Myocardial samples that underwent electron microscopy and immunohistochemical analysis showed myofilament changes in Orai3 KO mice with misexpression of cardiac contractile proteins and profound sarcomere disarray. Transverse aortic constriction (TAC) was used as a chronic stressor on the younger mice to determine whether the ability to compensate against a pathologic insult is compromised in the Orai3 KO heart. Orai3 KO mice presented with significantly reduced systolic function and ventricular dilation that deteriorated into congestive HF within 4 weeks post-surgery, while constricted WT hearts remained well-adapted throughout.

Conclusions:
Thus, our results identify Orai3 critical role in adult cardiac function and demonstrate a novel cardioprotective role of Orai3 against cardiac pressure overload-induced heart failure.
Abstract 923: Pharmacological Activation of Ampk With a Direct Pan-ampk Activator Results in a Worsening of a Hf Phenotype in Mice
Authors: Miller Russell A , Cameron Kimberly , Flynn Declan
Published: October 2019

The absence of effective therapeutic treatments that can restore function in patients with heart failure necessitates the identification of new mechanisms and strategies to improve outcomes. Strategies that directly target the cardiomyocyte and have potential to increase metabolic capacity hold promise as treatment modalities. We sought to evaluate direct activators of the AMP-Activated Protein Kinase (AMPK) in a model of HF to test for improvements. The pan-AMPK activator PF-739 resulted in activation of AMPK, phosphorylation of the downstream target ACC, and increases in glucose uptake after a single dose in vivo. PF-739 resulted in an increase in the gene expression of relevant transcriptional regulators PGC1α and NR4a1, suggesting potential for beneficial effects on substrate metabolism in a HF model. PF-739 and the ACE inhibitor Enalipril were used in a combined TAC/MI model of mouse HF. 4 weeks after injury the animals treated with PF-739 had an increase in end systolic and diastolic volume and ejection fraction compared to vehicle animals. Enalipril treatment resulted in modest improvements in echo heart assessments and a reduction in heart weight compared to vehicle animals. To understand the mechanism for impaired heart function in HF we assessed the impact of PF-739 on systemic blood pressure, reasoning this could impact HF progression in the model. PF-739 caused an increase in blood pressure after acute dosing in mice and rats. A small molecule analogue of PF-739 differing in one methyl group with dramatically reduced AMPK activity was shown to have no detectable blood pressure effect, suggesting the blood pressure effects are related to AMPK activity. Contrary to expectation, treatment with PF-739 caused impairment in heart function in a mouse model of HF, an effect that may be the result of a systemic blood pressure effect of the compound.
Abstract 925: Insulin Inhibits β-adrenergic Receptor Resensitization Through PI3KγInsulin Inhibits β-adrenergic Receptor Resensitization Through PI3Kγ
Authors: Sahu Anita , Mohan Maradumane , Prasad Sathyamangla V. Naga
Published: October 2019

Insulin regulates cardiac metabolism, myocyte survival, and cardiac growth. In addition, insulin is also known to modulate beta adrenergic receptors (βARs) function in the heart regulating cardiac function. βAR function in response to its agonist epinephrine/norepinephrine is regulated by G-protein coupled receptor kinase (GRKs) driven desensitization and protein phosphatase 2A (PP2A) mediated resensitization. Although insulin is known to modulate βAR function through GRKs, less is known about role in insulin in regulating resensitization mechanisms. Phosphoinositide 3-kinase γ (PI3Kγ) is a key regulator of resensitization at it inhibits PP2A activity and therefore, we tested whether insulin could mediate βAR dysfunction through inhibition of resensitization. Insulin stimulation of HEK 293 cells stably expressing β
2
ARs resulted in significant β
2
AR phosphorylation. This β
2
AR phosphorylation was completely abolished with use of pharmacologic inhibitors of PI3K wortmannin or LY 294002 and knock-down of PI3Kγ showing an essential role for PI3Kγ in regulation of βAR function by insulin. Activation of insulin receptor induces downstream signaling via recruitment of the adaptor insulin receptor substrates (IRS). Interestingly, our data suggests that cross talk between the IRs and B
2
ARs are dependent on interaction between PI3Kγ, GRK2 and IRS as identified by co-immunoprecipitation studies and use of surface plasmon resonance using purified proteins. Since cardiomyocytes and fibroblasts represent major cell-types in the heart, primary adult cardiomyocytes and cardiac fibroblasts (CFs) were isolated from WT and PI3Kγ KO hearts for insulin stimulation. While β
2
AR phosphorylation was completely abolished in primary CFs from PI3Kγ KO compared to WT CFs, cardiomyocytes did not show any differences in β
2
AR phosphorylation in response to insulin. These data suggest that PI3Kγ may differentially regulate pathways in cardiomyocytes and CFs in the heart indicating the existence of cell-specific signaling mechanisms that may underlie response to insulin and thereby the cardio-metabolic process.
Abstract 926: Regulation of Fibrosis by Phospholipase Cεin Cardiac Fibroblasts
Authors: Brown Loren M , Smrcka Alan V
Published: October 2019

Cardiac fibrosis is commonly associated with heart diseases, such as cardiac hypertrophy and myocardial infarction. Upon injury to the heart, cardiac fibroblasts transition to an activated myofibroblast state, driven by TGFβ or angiotensin II (AngII) signaling, characterized by expression of α-smooth muscle actin (αSMA). Fibrosis is driven by the activity of both cardiac myofibroblasts and inflammatory cells. Activation of cardiac fibroblasts leads to the induction of pro-inflammatory cytokines that are important for recruitment of immune cells and regulation of cardiac remodeling. Monocyte Chemoattractant Protein (MCP)-1/CCL2 is a chemokine expressed by cardiac myofibroblasts through activation of Nuclear Factor-kB (NF-kB) that leads to recruitment of mononuclear cells. Phospholipase Cε (PLCε) is highly expressed in cardiac fibroblasts and is activated by multiple upstream stimuli including GPCRs and RTKs, leading to protein kinase C (PKC) and D (PKD) activation and Calcium release. In this study to elucidate the role of PLCε in neonatal rat cardiac fibroblasts adenovirus encoding for a PLCε-shRNA was used to knockdown PLCε in fibroblasts. Treatment with PLCε-shRNA strongly inhibited the transition to myofibroblasts induced by TGFβ as assessed by staining of αSMA. PLCε knockdown did not inhibit the ability of TGFβ to induce SMAD nuclear translocation. PLCε depletion also strongly inhibited, basal, Thrombin, and AngII mediated PLC activity in cardiac fibroblasts, indicating PLCε is a dominant regulator of phosphoinositide hydrolysis in these cells. PLCε shRNA also decreased expression of MCP-1 mRNA and reduced the ability of pro-fibrotic stimuli to induce MCP-1 mRNA expression. Knockdown of PLCε or inhibition of PKD with the small molecule inhibitor NB 142-70 reduced the ability of thrombin to activate NF-kB. These data indicate that PLC signaling, and PLCε in particular, plays an important role in pro-fibrotic processes in cardiac fibroblasts, through both cell autonomous and paracrine mechanisms. Future studies will focus on further elucidating the mechanistic role of PLCε in the transition to myofibroblasts, and will study in
in vivo
models of cardiac fibrosis.
Abstract 931: Compensatory Response of Perivascular Adipose Tissue to Vascular Dysfunction in Metabolic Syndrome Rats Involves Apelin
Authors: Kagota Satomi , Shimari Miho , Maruyama-Fumoto Kana , Iwata Saki , Shinozuka Kazumasa
Published: October 2019

Perivascular adipose tissue (PVAT) regulates vascular homeostasis including vascular tone via release of adipokines. Using SHRSP.Z-

Lepr
fa

/IzmDmcr (SHRSP.ZF) rats, an animal model of metabolic syndrome (MetS), we have demonstrated that mesenteric PVAT enhances vasodilation under impaired vasodilation, in response to nitric oxide. We have also shown that the compensatory effect of PVAT disappears later in the course of MetS. Apelin is an adipokine that is produced at high levels in obesity and acts as a vasorelaxing factor. In this study, we evaluated the role of apelin in the enhancing effect of mesenteric PVAT on relaxations in SHRSP.ZF rats, by examining whether apelin canenhance vasorelaxation in the mesenteric arteries of SHRSP.ZF rats without PVAT, as it does in those with PVAT. Furthermore, we investigated whether apelin expression changes with increasing age. SHRSP.ZF rats at 17, 20, 23, and 30 weeks old were used. The mesenteric artery and surrounding adipose tissue were isolated from each rat; PVAT samples were isolated from surrounding adipose tissue; and the mRNA transcript level of apelin was examined by quantitative real-time PCR assays. Mesenteric arterial ring preparations with and without PVAT were made, and after a stable contraction was obtained by adding phenylephrine, relaxation was elicited using acetylcholine in the presence or absence of apelin (100 ng/mL, 20 min). There was no significant difference in apelin mRNA levels between 17 and 20 weeks, but there was a decrease at 23 and 30 weeks of age, which was when the enhancing effect of PVAT on vasodilation in SHRSP.ZF rats was impaired. In the presence of apelin, acetylcholine-induced relaxation in arteries without PVAT was significantly increased to the level of the response in arteries with PVAT in SHRSP.ZF rats at 20 weeks. These findings suggest that apelin is involved in the enhancing effect of PVAT in MetS rat mesenteric artery, and decreases in the level is associated with deterioration of PVAT function. Further study to investigate the mechanisms underlying the decrease in apelin production with increasing age in metabolic syndrome is needed, butthe apelin level could be one of the predictors for development of cardiovascular complications in patients with MetS.
Abstract 932: Translated Alternative Isoforms Coincide With Disordered Sequences in the Cardiac Proteome
Authors: Lau Edward , Han Yu , Williams Damon , Lam Maggie PY
Published: October 2019

Introduction:
Alternative splicing is widely implicated in cardiac development and diseases, but few isoform transcripts have ever been empirically observed as translated proteins. We aim to understand how alternative splicing diversifies proteome function.

Method:
We show an RNA-seq guided proteomics approach, comprising a custom pipeline of sequence read alignment, splice junction determination, and in silico filtering and translation to identify alternative isoforms across multiple cell types and anatomical regions of the human heart. We further applied the method to a time course study of human iPSC differentiation into cardiomyocytes, collecting isotope-tagged quantification data on a Q-Exactive HF mass spectrometer to examine isoform expression patterns during myocyte differentiation. We cataloged the translated non-canonical isoforms in the heart, and characterized sequence features upon which the empirically observed alternative sequences impinge.

Result:
We identified 1,216 distinct non-canonical isoform sequences at 1% FDR, including 143 sequences from 107 genes not found in the comprehensive databases TrEMBL and RefSeq. We observed tissue-specific and differentiation stage-specific differences in isoform expression patterns. The data show a proteome-wide enrichment of translated alternative isoforms sequences at intrinsically disordered regions of proteins with implication on isoform function. We observed examples where protein PTMs may be modulated by the exclusion of modification sites via splicing including a novel isoform we found in MYBPC3 which coincides with PKA-mediated phosphorylation implicated in diastolic function regulation in animal models.

Conclusion:
This is the first study to combine experimental RNA-seq and proteomics to investigate how splicing impacts the human cardiac proteome. The approach may avail understanding of the functional outcome of splicing and its role in disease mechanisms.
Abstract 934: Physical and Genetic Interaction Analyses in Human Pluripotent Stem Cell-Derived Cardiomyocytes to Study Protein Quality Control Disease in the Heart
Authors: Perez-Bermejo Juan A , Judge Luke M , Wu Kenneth , Jensen Christina L , Kaake Robyn M , Swaney Danielle , So Po-Lin , Krogan Nevan J , Conklin Bruce R
Published: October 2019

Cardiomyocytes must maintain constant contractile function of the heart throughout a human lifetime. To achieve this, a complex network of chaperones and other proteins maintains the homeostasis of the proteins in the cell. Protein quality control pathways are increasingly recognized for their importance in both inherited and sporadic cardiac disease, and as potential therapeutic targets. The co-chaperone BAG3 is particularly interesting, because genetic evidence suggests that variants of BAG3 can be both pathologic and protective. However, understanding the molecular mechanism underlying most of these disease-genetic variant associations remains a major challenge. Unbiased analysis of physical and genetic interaction networks holds the potential to provide critical information to fill in this knowledge gap. Using genome engineering tools, we have generated a series of isogenic human induced pluripotent (iPS) cell lines bearing different variants on the BAG3 gene, along with an epitope tag fusion. Using mass spectrometry methods, we have been able to identify interacting partners for the BAG3 protein expressed at endogenous levels in iPS-derived cardiomyocytes. Our results show a surprisingly high number of cardiac-specific interactions. In addition, some BAG3 protein variants present distinct gain or loss of specific interactions, allowing us to narrow down the list of candidate hits. Using microscopy image analysis, we performed a targeted knockdown screening on BAG3 interaction partners to dissect pathways of BAG3 interactors that are involved in the development disease phenotype.We hope the information obtained from this study will improve our understanding of the heart proteostasis network, enable the identification of potential therapeutic targets, and provide clues towards a broader understanding of the role of genetic variation in complex disease.
Abstract 936: Entropyx of Cardiac Rhythm Uniquely Predicts Mortality in a Multi-site Polysomnography (psg) Study of Ambulatory Asymptomatic Community Adults With Heart Failure
Authors: Umapathi Priya , Samson Mackenzie , Hajizadeh Negin , Lin Tracie , Conway Ginger A , Gullar Elliseo , O'Rourke Brian , McGinn Thomas , Jones Steven R , DeMazumder Deeptankar
Published: October 2019

Introduction:
Heart failure (HF) is associated with high rates of mortality and hospital readmission. Current strategies for risk stratification are limited. Recently, we introduced EntropyX, a novel measure of non-linear patterns underlying physiological variability using newer concepts of entropy estimation and machine learning. EntropyX of cardiac repolarization (EntropyX
QT
) enhanced the predictive value of all established risk factors in a multicenter study of HF patients (PMID: 27044982). Herein, we test the
hypothesis
that EntropyX of ventricular activation (EntropyX
RR
) during sleep enhances the performance of established mortality risk factors in asymptomatic community adults with HF. We interpret our results in context of fundamental mechanistic studies in animal models and modern theories of systems biology.

Methods & Results:
We followed 96 NYHA class I HF adults in sinus rhythm for 6.5±3.0 years (1994-2011; SHHS NCT#00005275). Baseline exposures included demographics, history, medications, labs, PSG metrics [e.g., sleep disordered breathing (SDB)], ECG analyses [e.g., heart rate (HRV), QT variability (QTV)], and EntropyX
RR
. The cohort had mean age of 70±10 years, 49% women, 11% African Americans, and 46 deaths (48%; N=35 from cardiovascular events) over 4.6±2.6 years. After adjusting for exposures, the adjusted hazard ratios (4th to 1st quartile) for mortality for EntropyX
RR
was 2.3 (95% CI, 1.1-4.6) and age was 4.5 (1.9-10.3), consistent with machine learning-based classification and regression tree analysis. Addition of EntropyX
RR
to a multivariate model (comprised of age, diabetes, myocardial infarction, SDB) improved continuous net reclassification by 43% (37-48).

Conclusions:
EntropyX
RR
during sleep predicts mortality over follow-up of asymptomatic community adults with HF, independent of conventional risk factors and linear/deterministic measures (e.g., HRV, QTV, SDB). Unlike simpler concepts of RR variability, EntropyX
RR
is a fundamentally different measure, reflecting the complexity of multi-directional physiological network properties that regulate homeostatic function under changing conditions. This new paradigm complements conventional measures of risk and has potential for broad application.
Abstract 938: BET Bromodomain Protein 4 (BRD4) Governance of Cardiovascular Disease Stress-related Cardiomyocyte Remodeling
Authors: Kim Soo Young , Altamirano Francisco , Schiattarella Gabriele G. , Jiang Nan , May Herman I. , Luo Xiang , Li Hongliang , Wu Shwu-Yuan , Chiang Cheng-Ming , Lavandero Sergio , Gillette Thomas G. , Hill Joseph A.
Published: October 2019

During the past decade, epigenetic control of cardiac remodeling has attracted attention as a major mechanism contributing to heart failure. The BET family of bromodomain proteins (BRD) functions as “readers” of acetylated chromatin. Pharmacological inhibition of BRD proteins prevents cardiac hypertrophy and heart failure in preclinical models, yet mechanistic studies elucidating the biology of BRD proteins in the heart are lacking. Here, we investigated the role(s) of BRD4 in cardiac physiology and pathophysiology. By engineering a cardiomyocyte-specific BRD4 knockout mouse, we discovered that loss of BRD4 triggered progressive decline in ventricular contractile function, culminating in dilated cardiomyopathy in both post-natal and adult hearts. To identify early transcriptomic changes in BRD4-ablated heart, we conducted a global transcriptome analysis in KO hearts prior to the onset of ventricular dysfunction. RNA sequencing analysis of BRD4 KO hearts revealed disruption of genes essential to mitochondrial energy production and homeostasis, as well as key cardiac sarcomeric components. Computational analysis identified key transcription factors involved in BRD4-mediated gene regulation, including MEF2 complex, ERR1, SRF, and Nkx2.5. By studying isolated cardiomyocytes maintained in primary culture, we confirmed that disruption of the candidate TF complexes by BRD4 ablation altered mitochondrial morphology and provoked progressive contractile dysfunction. In aggregate, we describe for the first time a critical role of BRD4 in regulating key cardiomyocyte gene networks, in particular genes involved in mitochondrial homeostasis and contractility, to maintain cardiac function. Moreover, our data suggest that BRD4 is a novel regulator of epigenetic events in dilated cardiomyopathy. Elucidating these novel roles of BRD4 in cardiomyocyte remodeling will provide critical insights into the epigenetic control of stress-related cardiac events with potential clinical relevance.
PAY GERİ ALIM DUYURULARININ PAY GETİRİLERİ ÜZERİNE KISA DÖNEM ETKİSİ: BIST İMALAT SEKTÖRÜ ÖRNEĞİ
Authors: TAŞDEMİR Ahmet , ALSU Erkan
Published: October 2019

Pay geri alım işlemi şirketlerin arz edilmiş toplam pay miktarının bir kısmını satın alarak ve bu sayede pay miktarını azaltıp,  geri kalan payların gelecekteki nakit akışı üzerindeki etkisini arttırması yoluyla yatırımcıya dolaylı olarak kar dağıtımını ifade etmektedir.  Ülkemizde son yıllarda kullanılmaya başlanan pay geri alımı,  dünya genelinde on yıllardır kullanılmaktadır. Pay geri alımı araştırmacılarında dikkatini çekmiş ve bu konu hakkında birçok çalışma gerçekleştirilmiştir. Bu çalışma da ise BIST İmalat sektöründe faaliyet gösteren şirketlerin pay geri alımları ele alınmış ve 2011 ve 2018 yılları arasında gerçekleştirmiş oldukları pay geri alım duyuruları ve bu duyuruların pay getirilerine etkisi incelenmiştir. Çalışmada olay çalışması (Event Study) metodu kullanılmıştır. Şirketlerin gerçekleştirmiş oldukları geri alım duyurularını takip eden kısa dönem içerisinde pay getiri performansının ölçülebilmesi amacıyla farklı pencerelerde AAR ve CAAR değerleri hesaplanmıştır. Bu kapsamda elde edilen bulgular İmalat sektöründe faaliyet gösteren şirketlerin gerçekleştirmiş oldukları hisse senedi geri alım duyuru tarihleri civarında pozitif anormal getirilerin elde edilebildiğini göstermektedir. Buna ek olarak, çalışma kapsamında pay geri alım duyurularının getiriler üzerindeki etkisi firma bazında da incelenmiş ve elde edilen sonuçlar değerlendirilmiştir.
A ZERO-SUM GAME: CUSTOMERS’ SWITCHING BEHAVIOR IN THE TURKISH GSM MARKET - A NEUROMARKETING ANALYSIS
Authors: BOZ Hakan , KOÇ Erdoğan
Published: October 2019

This
study aims to measure the emotional responses of existing customers to their
GSM operators after exposed to the other GSM operators’ sales promotion
campaigns aimed at attracting new customers. 
The study also aims to measure customers’ brand loyalty towards their
GSM operators before and after the exposure to these sales’ promotion
campaigns. The emotions of the customers towards GSM operators’ promotions were
measured by using a Facial Recognition Software, an eye tracker device and a questionnaire.
The results of this study show that even if the customers are satisfied with
their GSM operators, they can switch from their current operators when they
encounter an attractive offer. Practitioners should focus more on customer
retention as opposed to acquiring new customers. Findings indicate that GSM
operators should consider their current customers in the long-term in
accordance with the damage that targeted promotions may have on them.
HEDGE FON PİYASALARINDA ZAMANLA DEĞİŞEN ZAYIF FORMDA ETKİNLİK
Authors: KAMIŞLI Melik , TEMİZEL Fatih
Published: October 2019

Günümüzde finansal piyasaların en büyük katılımcılarından
biri, bireysel yatırımcıların yanı sıra kurumsal yatırımcıların da ilgisini
çekmeye başlayan hedge fonlardır. Hedge fon yatırımcılarının karar sürecinde değerlendirdikleri
temel girdi fonun göstereceği performanstır. Bu noktada yatırım kararı
aşamasında fonun performansı üzerinde etkili olan faktörler de analiz
edilmelidir. Bu faktörlerden biri de yatırım yapılması düşünülen hedge fon
piyasasının etkinlik yapısıdır. Bununla birlikte piyasa etkinliği yatırım
süresi boyunca piyasadaki farklı gelişmelere bağlı olarak değişebilmektedir. Bu
bağlamda çalışmanın temel amacı, bölgesel hedge fonların zamanla değişen zayıf
formda etkinlik yapısının belirlenmesidir. Bu amaca uygun olarak Asya, Batı
Avrupa, Kuzey Amerika, Kuzey Avrupa, Latin Amerika, MENA ve Rusya/Doğu Avrupa
bölgesel hedge fonlarının öncelikle doğrusallık yapısı Harvey vd. (2008)
doğrusallık testi ile sınanmış, ardından doğrusal olmayan hedge fon
endekslerine zamanla değişen KSS birim kök testi uygulanmıştır. Çalışma
sonucunda incelenen bölgesel hedge fon piyasalarında zayıf formda etkinliğin
zamana bağlı olarak değişim gösterdiği tespit edilmiştir.
Predictive Impact of Contextual Objects during Action Observation: Evidence from Functional Magnetic Resonance Imaging
Authors: El-Sourani Nadiya , Trempler Ima , Wurm Moritz F. , Fink Gereon R. , Schubotz Ricarda I.
Published: October 2019

The processing of congruent stimuli, such as an object or action in its typical location, is usually associated with reduced neural activity, probably due to facilitated recognition. However, in some situations, congruency increases neural activity—for example, when objects next to observed actions are likely versus unlikely to be involved in forthcoming action steps. Here, we investigated using fMRI whether the processing of contextual cues during action perception is driven by their (in)congruency and, thus, informative value to make sense of an observed scene. Specifically, we tested whether both highly congruent contextual objects (COs), which strongly indicate a future action step, and highly incongruent COs, which require updating predictions about possible forthcoming action steps, provide more anticipatory information about the action course than moderately congruent COs. In line with our hypothesis that especially the inferior frontal gyrus (IFG) subserves the integration of the additional information into the predictive model of the action, we found highly congruent and incongruent COs to increase bilateral activity in action observation nodes, that is, the IFG, the occipitotemporal cortex, and the intraparietal sulcus. Intriguingly, BA 47 was significantly stronger engaged for incongruent COs reflecting the updating of prediction in response to conflicting information. Our findings imply that the IFG reflects the informative impact of COs on observed actions by using contextual information to supply and update the currently operating predictive model. In the case of an incongruent CO, this model has to be reconsidered and extended toward a new overarching action goal.
Perturbing Neural Representations of Working Memory with Task-irrelevant Interruption
Authors: Hakim Nicole , Feldmann-Wüstefeld Tobias , Awh Edward , Vogel Edward K.
Published: October 2019

Working memory maintains information so that it can be used in complex cognitive tasks. A key challenge for this system is to maintain relevant information in the face of task-irrelevant perturbations. Across two experiments, we investigated the impact of task-irrelevant interruptions on neural representations of working memory. We recorded EEG activity in humans while they performed a working memory task. On a subset of trials, we interrupted participants with salient but task-irrelevant objects. To track the impact of these task-irrelevant interruptions on neural representations of working memory, we measured two well-characterized, temporally sensitive EEG markers that reflect active, prioritized working memory representations: the contralateral delay activity and lateralized alpha power (8–12 Hz). After interruption, we found that contralateral delay activity amplitude momentarily sustained but was gone by the end of the trial. Lateralized alpha power was immediately influenced by the interrupters but recovered by the end of the trial. This suggests that dissociable neural processes contribute to the maintenance of working memory information and that brief irrelevant onsets disrupt two distinct online aspects of working memory. In addition, we found that task expectancy modulated the timing and magnitude of how these two neural signals responded to task-irrelevant interruptions, suggesting that the brain's response to task-irrelevant interruption is shaped by task context.
Marx, the “Asiatic Mode of Production,” and “Oriental Despotism” as “True” Socialism
Authors: Shlapentokh Dmitry
Published: October 2019

Marx believed that socialist revolution, i.e., the end of the private ownership of the “means of production”, would make the state weak in the long run: the state would “wither away”. He also believed that the despotic state is related to Oriental despotism, marked by general ossification. Here Marx followed the views of his contemporaries. The socialist revolutions in Russia and China demonstrate that Marx was wrong: the end of private ownership of the “means of production” creates a state similar to Oriental despotism, but it is a quite dynamic and economically viable regime. The USSR’s collapse was due to Gorbachev alone; at the same time, totalitarian socialist China would become an economic and geopolitical global force in the future.