bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 340: Heat Shock Proteins HSP90 and HSP70 Mediate Opioid- and GSK3β-induced Cardioprotection
Authors: Jimenez Sarah K , Small Bryce A , Hsu Anna K , Gross Garrett J , Gross Eric R 
Published: July 2021

Previously, opioids were established to reduce myocardial injury in an ischemic preconditioning (IPC)-like manner, involving a central and downstream role of glycogen synthase kinase-3 beta (GSK-3β) inhibition. However, the mechanism of GSK-3β inhibition mediating cardioprotection and the protein partners involved has not been fully elucidated. Hence, we used a non-biased sequence scan of the proteome to determine potential GSK-3β protein partners and tested whether two candidate proteins, heat shock proteins (HSP) 70 and 90, are involved in the mechanism of opioid-induced cardioprotection.
A non-biased BLAST search was performed for putative GSK-3β target substrates, based upon the sequence motif S/T-X-X-X-S/T. Approximately 700 proteins were identified to have this moiety, including many of the HSP protein class, including HSP70 and HSP90. To determine whether HSP70 or HSP90 are indeed important in opioid-induced cardioprotection, rats were subjected to an in vivo myocardial ischemia-reperfusion protocol consisting of 30 minutes of ischemia and 2 hours of reperfusion of the left anterior descending coronary artery followed by infarct size assessment. Either morphine (0.3mg/kg) or inhibition of GSK-3β using SB216763 (0.6mg/kg), reduced infarct size compared to control (42.21±1*% and 41.09±2*%, respectively versus control 60.38±1.2, *P<0.01). Inhibition of HSP70 using desoxysperguanalin (DSG), or HSP90 using radicicol (RAD), abrogated morphine-induced protection (56.09±2 and 58.64±1, respectively). Either DSG or RAD partially inhibited protection in the presence of GSK-3β (47.28±1.071 and 49.88±3.09). Our results suggest that morphine-induced cardioprotection occurs by a HSP70 and HSP90- dependent mechanism, with this HSP machinery partially required for GSK3β-inhibition-induced cardioprotection. Further understanding of this mechanism is important, considering many agents targeting HSP are currently in development as novel cancer treatments, which may have detrimental effects on the myocardial salvage mediated by opioids or by GSK3β-inhibition.
Abstract 39: Frequency of the Angiotensin Converting Enzyme (I/D) and β1 Adrenergic Receptor (Arg389Gly) Gene Polymorphisms in a Sample of Mexican Population
Authors: Cervantes Minjares Juan Pablo , De la Torre Zazueta Manuel Alejandro , Hernández Pacheco Guadalupe 
Published: July 2021

Introduction:
The angiotensin converting enzyme (ACE) is involved in blood pressure regulation. The I/D polymorphism of ACE has been associated with hypertension, left ventricular hypertrophy and metabolic syndrome.

The β1 adrenergic receptor (ARβ1) is located mainly in the heart, its activation has a chronotropic and inotropic effect. The Arg389Gly polymorphism of ARβ1 has been associated with dilated cardiomyopathy, atrial fibrillation and vasovagal syncope.
The identification of these polymorphisms in a control group, will reveal the frequencies in healthy mexican population so we can compare with the diseased population and seek association with different diseases.

Objective:
Identifying gene and allelic prevalence in a healthy population.

Material and Methods:
We worked with 45 samples from healthy individuals, 36 males and 9 females, with a median age of 35.8 ± 16.1 and a BMI of 25.81 ± 4.6.

Extraction of DNA from 10 ml of peripheral blood. ACE polymorphism was determined by direct PCR. The determination of the Arg389Gly polymorphism was by PCR-RFLP.

Results:
The gene frequency of the ACE gene in 39 subjects was: DD 33.33% (13 of 39), ID 38.46% (15 of 39) and II 28.2% (11 of 39). The allelic frequency: I 47.43% and D 52.56%.

Arg389Gly polymorphism frequency was in 11 subjects: ArgArg 9% (1 of 11), ArgGly 72.7% (8 of 11) and GlyGly 18.2% (2 of 11). The allele frequency: 45% Arg and Gly 55%.

Conclusions:
DD homozygote frequency differs from that observed in the study of Vargas et al., which is lower. This is important because the D allele is associated with greater activity and concentration of ACE, which may predispose to cardiovascular disease in our population.

Regarding the Arg389Gly polymorphism, it has been observed that the Gly allele is linked to cardiovascular disease and the response to beta-blockers.
Our population showed an increase of Gly allele carriers, so they may be more susceptible to these diseases.
It is important to know the frequency of these polymorphisms in our population, and identify that they can impact in medical treatment or may serve as potential predictors of cardiovascular disease.
Abstract 129: Inhibition of MEF2 By Atenolol Modifies the Transcriptome During Cardiac Hypertrophy to Improve Heart Function
Authors: Wales Stephanie , Hashemi Sara , Dadson Keith , Tuerdi Subat , Zhao Jian , Sweeney Gary , Grigull Jorg , McDermott John C 
Published: July 2021

Cardiac hypertrophy is a growth response of the adult heart that often results from increased mechanical loading due to high blood pressure and myocardial damage caused by ischemic heart disease. The β1 selective β-adrenergic antagonist, atenolol, is historically one of the most frequently prescribed of all medicines used to preserve heart function following myocardial damage. Transcription factor, myocyte enhancer factor 2 (MEF2), is required for early cardiac development and has also been implicated in cardiac hypertrophy. The effect of β-blockade on the gene program that is activated following cardiac hypertrophy as heart failure progresses is not fully understood. Here we show that treatment with atenolol leads to in vivo changes within the murine heart to reverse cardiac hypertrophy, and this is accompanied by repression of MEF2 activity.
Cardiac hypertrophy was simulated using transverse aortic constriction (TAC) for four weeks in a transgenic MEF2-lacZ mouse model, followed by six weeks of vehicle (AT-) or atenolol treatment (AT+). Physiological responses in cardiac function, fibrosis, and cardiomyocyte size in TAC+AT+ mice were consistent with cardiac hypertrophy and demonstrated increased MEF2 activity compared to control (TAC-AT-). Atenolol treatment resulted in an overall improvement in cardiac function of TAC+ mice, showing a decrease in cardiomyocyte size, fibrosis and MEF2 activity. RNA was isolated from the left ventricle of the heart to determine changes in mRNA and lncRNA using RNA-seq. Atenolol reversed the expression of a specific subset of genes and lncRNA that become upregulated by TAC which corresponded to gene ontology terms related to metabolism and the immune system.
Together, these data demonstrate that atenolol treatment during cardiac hypertrophy inhibits MEF2 activity and concomitantly leads to improved cardiac function. Thus, inhibition of MEF2 may be necessary to improve or reverse the effects of long-term heart failure.
Abstract 134: Reciprocal Cardiac Chromatin Regulation by Ctcf and Hmgb2
Authors: Rosa-Garrido Manuel , Monte Emma , Karbassi Elaheh , Chen Haodong , Rau Christoph , Wang Jessica , Lusis Aldons J , Wang Yibin , Vondriska Thomas M 
Published: July 2021

Chromatin remodeling plays an essential role in cardiac gene reprogramming under pathological conditions. However, we currently lack a detailed understanding of how this process is structurally coordinated across the genome. Previous RNA and proteomic analyses of an in vivo model of heart failure performed by our group identified the chromatin structural proteins CTCF and high mobility group protein B2 (HMGB2) as regulators of heart disease. CTCF is an essential factor in the maintenance of global chromatin organization through the facilitation of long-range interactions and chromatin looping. HMGB2 is a non-nucleosomal structural protein that packages nucleosomes into higher order structures.
An unbiased genomic analysis of ~100 strains of mice treated with isoproterenol (ISO) followed by transcriptome and phenotype analyses revealed a general down-regulation of CTCF at the mRNA level across the different strains after ISO treatment, whereas the HMGB2 response was strongly influenced by common genetic variation (i.e. between strains). ChIP-seq data, ChIP-reChIP-PCR experiments (detection of concomitant presence of two proteins at a given locus) and immunofluorescence showed CTCF and HMGB2 bind the same regions of the genome, yet they do not physically co-localize in myocyte nuclei. Loss of HMGB2, which induces hypertrophy in myocytes, causes de-condensation of chromatin, as directly measured by micrococcal nuclease digestion; CTCF knockdown has no effect on global chromatin accessibility by this assay. Examination of other chromatin structural proteins like histone H1 suggests this interaction between CTCF and HMGB2 is specific. Lastly, we showed that CTCF and HMGB2 regulate each other’s expression as well as the transcription of cardiac hypertrophy genes and ribosomal RNA. Our data show that basal HMGB2 (but not CTCF) expression correlates with cardiac mass. The response of HMGB2 levels to heart failure stimuli is highly influenced by genetics, whereas the decrease in CTCF following (ISO) is unaffected by genetic variation. These findings reveal molecular mechanisms of chromatin compaction in cardiac cells, linking them with genetic variability, and revealing a reciprocal relationship between HMGB2 and CTCF in cardiac hypertrophy.
Abstract 18: Increasing in vivo Apoa1/HDL Levels Negates the Cardiotoxic Effects of Doxorubicin, and Involves Signalling Through SR-BI, PI3K, and AKT1
Authors: Durham Kristina , Thomas Cyrus , Trigatti Bernardo L 
Published: July 2021

Doxorubicin (DOX) is a clinically used anti-tumor drug, though the use of DOX is limited by its potent cardiotoxic side effect that can lead to heart failure. HDL protects isolated cardiomyocytes against DOX induced apoptosis, though whether this effect translates in vivo has yet to be determined. Here we assess whether ApoA1/HDL overexpression can protect mice in vivo against DOX induced cardiotoxicity, and explore the intracellular signalling mechanisms involved in protection.
Mice overexpressing human ApoA1 (ApoA1tg/tg) and ApoA1+/+ mice were treated chronically with DOX, and effects on cardiac function and cardiomyocyte health were assessed. Over expression of human ApoA1 in mice corresponded to ~2.5 fold increase in plasma HDL-C as compared to ApoA1+/+ mice. Following 5 weekly injections of 5mg/kg DOX, ApoA1+/+ mice displayed cardiac dysfunction as evidenced by reduced left ventricular developed pressure, and reduced rate of pressure development. In contrast, left ventricular function was maintained following DOX treatment in ApoA1tg/tg mice. Histological analysis revealed reduced cardiomyocyte cross-sectional area and increased cardiomyocyte apoptosis following DOX treatment in ApoA1+/+ mice. ApoA1tg/tg mice, on the other hand, were protected against DOX induced cardiomyocyte atrophy and apoptosis. Interestingly, pAKT:tAKT was reduced in ApoA1+/+ by treatment with DOX, but the ratio was maintained in ApoA1tg/tg mice.
We evaluated the roles of SR-BI, PI3K, and AKT1/2 in the signalling cascade of HDL in neonatal mouse cardiomyocytes and human immortalized ventricular cardiomyocytes. Through inhibition of AKT and PI3K, and knockdown or knockout of SR-BI, AKT1, and AKT2, we demonstrated that SR-BI, PI3K and AKT1 are required for HDL mediated protection against DOX induced cardiomyocyte apoptosis.
Our results provide evidence for ApoA1 mediated protection against DOX cardiotoxicity in vivo and demonstrate the roles of SR-BI, PI3K, and AKT1 as mediators in the protective effect.
Abstract 183: Improved Ca-cycling by Dexamethasone Preserves Contractility After Ischemia/Reperfusion in Diabetic Rat Cardiomyocytes
Authors: Schach Christian , Goetz Michael , Busse Hendrik , Zausig York , Drymalski Marzena , Maier Lars , Wagner Stefan 
Published: July 2021

Glucocorticoid receptor (GR) stimulation is essential for normal heart function and dexamethasone (DEX) treatment has been shown to reduce ischemia reperfusion injury (IRI). Prevalence of diabetes is increasing and myocardial infarction in such patients is more severe and risk of complications is augmented. We tested the hypothesis, that GR stimulation with DEX protects diabetic myocardium from IRI by improving Ca cycling.

Cardiomyocytes from type 2 diabetic Zucker diabetic fatty rats were isolated and cultured in DEX (10 μg/mL) vs. vehicle for 24h. [Ca]

i

and fractional shortening (FS) was measured in electrical field-stimulated cardiomyocytes loaded with Fura-2 AM (10 μM). Compared to control, DEX-treated cells display increased Ca transient amplitude (0.33±0.03 vs. 0.46±0.04, P = 0.01, n=6 animals) and FS (fig.) DEX also significantly increased sarcoplasmic reticulum (SR) Ca content (Caffeine, 10 mM) and reduced SR Ca leak measured as Ca spark frequency (SpF), fluo-4 loaded myocytes, confocal microscopy (fig.).

To test, whether DEX reduced IRI, rats were treated with DEX (2 mg/kg i.p.) 24h before measurement (vehicle as control). Left ventricular developed pressure (LVDP) was monitored in Langendorff-perfused-hearts during global ischemia for 30 min and reperfusion. During reperfusion, DEX-treated hearts showed significantly greater LVDP (P < 0.05, 2way ANOVA, fig.).
In diabetic rats, glucocorticoid receptor stimulation with DEX leads to a more efficient Ca cycling with reduced SR Ca leakage, which translates to an increased contractility on the cellular level and protection against ischemia reperfusion injury in the whole organ.
Abstract 204: Detection and Determination of Protein Network Associated With Atrial Fibrillation Subtypes
Authors: Mohamed Salah A. , Hanke Thorsten , Klein Oliver , Thiele Herbert , Sievers Hans H. , Yan Junfeng 
Published: July 2021

Atrial fibrillation (AF) is associated with increased risks of stroke, cardiac failure, and mortality. The underlying mechanisms and pathology of AF remain elusive. The aim of this study is to proteomically analyze the left atrial appendage tissue obtained from patients suffering from subtypes (paroxysmal, persistent, and long-standing persistent) AF.
MALDI Imaging mass spectrometry (MALDI-IMS) was applied to differentiate in classification of pathophysiological AF subtypes, through the direct (in situ) analysis of formalin-fixed paraffin embedded (FFPE) left atrial appendage (LAA) tissue. FFPE LAA tissue were collected from patients with predisposed paroxysmal (n = 9, mean age 69.0±3.1 years), persistent (n = 18, mean age 67.0±2.7 years), and long-standing persistent AF (n = 19, mean age 71.0±2.0 years). Sections were dewaxed and thereupon soused by trypsin solutions using an automated spraying device. Spectra were acquired at a mass range of m/z 800-3500Da and lateral resolution of 80 μm. Two hundred laser shots were acquired per pixel and random walk of 50/position. Data analyses were performed using SCiLS Lab software.
Component analysis of MALDI Imaging data through probabilistic latent semantic analysis results in a clear discrimination in the first 3 components of atrial fibrillation. Employing receiver operating characteristic analysis (AUC > 0.7), characteristic intensity distribution in given m/z values, which are discriminative for the considered cluster, was determined to distinguish between paroxysmal vs. persistent AF, and persistent vs. long-persistent AF, m/z values were determined between persistent vs long-persistent AF (1.59±0.12 vs 6.85±3.02, p = 0.02). Follow-up of neurological events in case-controlled assessment presented 13±12% in paroxysmal, 56±12% in persistent and 42±12% long-persistent AF.
The tissue-based proteomic approach provides clinically relevant beneficial information in improving risk stratification for AF patients. In the future, this obtained information might be considered new biomarker to support the diagnosis of the severity of AF status. They also suggest a new criterion to determine the most appropriate procedure for each AF subtype to improve postoperative outcomes.
Abstract 215: The Role of Titin in Cardiac Function: Studies in Two Genetically Engineered Mouse Models With Disparate Titin’s Size
Authors: Methawasin Mei , Hutchinson Kirk R , Smith John E , Granzier Henk L 
Published: July 2021

Titin, a myofilament that acts as a molecular spring in the sarcomere, is considered the main contributor to passive stiffness of cardiomyocytes and is responsible for cardiac diastolic function. Increased titin stiffness is related to diastolic dysfunction and HFpEF (Heart Failure with preserved Ejection Fraction). Alteration in size of titin’s spring region leads to changes in cardiomyocyte and left ventricular (LV) chamber stiffness.
We tested the effect of alteration in titin’s size in two genetically engineered mouse models. We investigated the effect of shortening titin’s spring region in a mouse model in which I-band/A-band region of titin’s spring has been deleted (TtnΔIAjxn ), in comparison to the effect of lengthening titin’s spring region in a mouse model deficient in titin splicing factor (Rbm20ΔRRM). Integrative approaches were used from single cardiomyocyte mechanics to pressure-volume analysis and exercise study.
Study of skinned LV cardiomyocytes revealed that cellular passive stiffness was inversely related to the size of titin. Cellular passive stiffness was increased in TtnΔIAjxn homozygous (-/-) (~ 110 % higher than wildtype (WT)) and was reduced in a graded manner in Rbm20ΔRRM heterozygous (+/-) and -/- cardiomyocytes (~61% and ~87% less than WT). This effect was carried through at the LV chamber level which could be demonstrated in pressure volume (PV) analysis as an increased end-diastolic pressure-volume relationship (EDPVR) in TtnΔIAjxn -/- (~110% higher than WT’s hearts) and reduced EDPVR in Rbm20ΔRRM +/- and -/- (~57% and ~48% less than WT’s hearts). Free-wheel running studies revealed a running deficiency in TtnΔIAjxn -/- mice but an increase in exercise capacity in Rbm20ΔRRM +/– mice.

Conclusions:
Functional studies from the cellular to in-vivo LV chamber levels showed that mice with shortening of titin’s spring region had increased LV stiffness, diastolic dysfunction and reduced exercise capacity, while mice with lengthening titin’s spring region had compliant LV and increased exercise capacity. Thus, our work supports titin’s important roles in LV diastolic function and suggests that modification of the size of titin’s spring region could be a potential therapeutic strategy for HFpEF.
Abstract 239: Augmented Cardiac Pyruvate Dehydrogenase Complex Flux During Hypoxia Increases Post-hypoxic Damage
Authors: Handzlik Michal K , Constantin-Teodosiu Dumitru , Greenhaff Paul L , Cole Mark A 
Published: July 2021

Modulation of cardiac pyruvate dehydrogenase complex (PDC) flux is known to alter post-ischemic myocardial injury. Hypoxia is intrinsic to ischemia, but its specific role in cardiac injury is unknown. We hypothesized that post-hypoxic cardiac injury would be attenuated with activation of the PDC complex during hypoxia.
Mouse hearts were isolated and Langendorff perfused with 0.4mM palmitate and 11mM glucose. Following 30min of normoxia, hearts were subjected to 30min hypoxia (20% of normoxic pO2) followed by 30min of reoxygenation. PDC flux was increased by infusion of 1mM dichloroacetate (DCA), either from onset of hypoxia, or with onset of reoxygenation. Cardiac function was measured using an IV balloon, and fatty acid β-oxidation determined via 3H-labelling. Lactate efflux was assayed from timed buffer collections. Hearts were frozen at end-normoxia, end-hypoxia and end-reoxygenation, and assayed for PDC flux, and phosphate metabolites. Reactive oxygen species formation was assessed by Western blotting of protein carbonyls.
End-hypoxic cardiac PDC flux fell to 41±5% of pre-hypoxic values (0.96 of 2.37 μmol/gdwt, p<0.001) with β-oxidation also lower (25±11%, 0.06 of 0.24 μmol/min/gwwt, p<0.025). Lactate efflux increased 2.3-fold (4.7 to 10.6 μmol/min/gwwt, p<0.028) and AMP/ATP ratio 5.3-fold (0.04 to 0.21 p<0.002). DCA infusion increased end-hypoxic PDC flux (170±16%, 1.64 of 0.96 μmol/gdwt, p<0.003), reducing lactate efflux (47±8%, 5 of 11 μmol/min/gwwt, p<0.021) and AMP/ATP ratio (43±12%, 0.09 of 0.21, p<0.025). Control hearts were damaged by hypoxia, final recovery being 63±7% of pre-hypoxic function (18 of 29 bpm.mmHg.103). Hypoxic DCA infusion impaired recovery (49±4%, 15 of 31 bpm.mmHg.103), compared to DCA infusion during reoxygenation (63±3%, 19 of 30 bpm.mmHg.103, p<0.023). Reactive oxygen species formation was not altered.
Increasing PDC flux during hypoxia significantly modified myocardial substrate metabolism. In contrast to the reported beneficial effects of augmented PDC flux during ischemia, increasing PDC flux in the hypoxic heart exacerbated myocardial injury. These results indicate that the potentially therapeutic effects of increasing PDC flux are not dependent on the hypoxic aspect of myocardial ischemia.
Abstract 329: The Human Pericardial Fluid is Enriched With Cardiovascular-expressed Micrornas and Exosomes Able to Elicit Therapeutic Responses
Authors: Beltrami Cristina , Shantikumar Saran , Shearn Andrew , Laftha Abas , Rajakaruna Cha , Angelini Gianni D , Emanueli Costanza 
Published: July 2021

Cells release functionally active microRNAs (miRs) into extracellular vesicles (EVs: exosomes and microparticles). In vitro, EVs shuttle miRs and other molecules between cells. The functional relevance of EVs in the context of human physiopathology is still debated.
We hypothesize that the pericardial fluid (PF) mediates myocardium cell-to-cell communication through EVs exchanges. Here, we aimed to (1) characterize human PF EVs and exosomal miRs; (2) investigate if PF EVs exert a biological function.
PF, plasma, thoracic aorta (TA) and right atrium appendage (RAA) samples were collected as leftovers from aortic valve replacement surgery. A miR array identified PF miRs expression. The top expressed cardiovascular miRs were measured (RT-qPCR) in TA and RAA (to validate expression in patients cardiovascular tissues), PF and plasma, and exosomes enriched from PF and plasma. EVs concentration and size distribution in PF and plasma were quantified by a nanoparticle tracking analysis system. The exosome functional activity was tested in human endothelial cells (ECs) and in a mouse model of limb ischemia (LI).
A pool of cardiovascular miRs (including miR-21 and -29a), were enriched in the PF in comparison to plasma, suggesting that the PF/plasma concentration gradients of cardiovascular miRs were caused by the trafficking of these miRs from the myocardium and thoracic vessels to the PF. This gradient was reverted for the negative control miR-122 (produced by the liver and undetectable in the PF). Exosomes were abundant in the PF, even if less concentrated than in plasma. PF-exosome treatment of ECs exposed to hypoxia significantly decreased cell apoptosis and increased cell proliferation (P<0.01 vs PBS). Local PF-exosomes delivery increased post-LI ischemic blood flow recovery (P<0.01 vs PBS). By contrast, plasma-exosomes were not effective (P=NS vs PBS).
We have provided the first characterization of EVs and exosomal miRs in the human PF and for first identified a therapeutic potential of PF- exosomes from cardiovascular patients. Future studies will be tailored to exploit the properties PF-exosome in regenerative medicine.