bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of cardiac effects of OPA1 protein promotion in transgenic animal model
Authors: Deres L , Ordog K , Horvath O , Bruszt K , Toth S Z , Gallyas F , Toth K , Halmosi R 
Published: October 2022

Abstract

Introduction
Mitochondria forms a dynamic network in cells, which is regulated by the balance between mitochondrial fusion and fission. The inhibition of mitochondrial fission could result in positive effects in acute ischemic/reperfusion injury models, due to prevention of mitochondrial membrane potential fall that goes along with fission processes. However, inhibition of fission in chronic models is disadvantageous because it obstructs the elimination of damaged mitochondrial fragments. OPA1 – in view of the previous results – a possible therapy target, as a fusion promoter and structure stabilizer protein.

Methods
We used transgenic mice in which OMA1 and YME1L cleavage spots of OPA1 were deleted. This resulted in higher representation of L-OPA1 compared to S-OPA1. After genotyping and model validation all animals were examined by echocardiograph and ECG on two occasions, at week 11 and 36. Histology samples were made from hearts, in case of mitochondrial morphology and structure remodelling examination. Cardiomyocytes were isolated from neonatal mice to determine the efficiency of mitochondrial respiration by SeaHorse assay method.

Results
Capillary Western immunoassay proved the presence and higher concentration of OPA1 in the TG animals. Echocardiographic examination showed a significant ejection fraction reduction in TG animals at week 36, but remodelling in histology samples could not be observed. The efficiency of mitochondrial respiration was decreased in TG animals compared to WT animals, according to the results of SeaHorse assay.

Conclusion
OPA1 protein promotion has a negative effect on systolic function during ageing. We confirmed that volume overload and ventricular remodeling did not manifested. The reason behind the loss of pump function might be at least partly the energy deficit due to the mitochondrial respiratory failure and the damage in mitochondrial quality control pathways.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The research in Hungary was funded by NKFIH within the framework of the project TKP2021-EGA-17.
Arginase 1 in erythrocytes is a critical modulator of cardioprotective signalling by nitric oxide and soluble guanylyl cyclase
Authors: Yang J N , Tratsiakovich Y T , Jiao T J , Mahdi A M , Tengbom J T , Zhou Z Z , Collado A C , Lundberg J L , Pernow J P 
Published: October 2022

Abstract

Background
Arginase is involved in the development of ischemia-reperfusion injury by regulating nitric oxide (NO) bioactivity via competition with NO synthase (NOS) for their common substrate L-arginine. Erythrocytes are known to contain high levels of arginase that may reduce export of cardioprotective NO bioactivity.

Aim
To determine the role of arginase 1 in erythrocytes for cardiac protection against myocardial ischemia-reperfusion injury.

Methods
A tie2 cre-flox mouse model, in which arginase 1 was deleted (Arg 1-KO) in hematopoietic and endothelial cells, was developed. In vivo ischemia-reperfusion was performed in anaesthetized mice by left anterior descending coronary artery ligation (30 min ischemia and 120 min reperfusion). To determine the specific role of erythrocytes, an isolated perfused mouse heart model was applied. Erythrocytes from Arg 1-KO and wild type (WT) mice were given to isolated hearts from WT mice at the onset of global ischemia. After 40 min ischemia, the recovery of left ventricular developed pressure (LVDP) during 60 min reperfusion was recorded as an indicator of cardiac functional recovery.
All animal experiments and procedures were performed according to the guidelines by the U.S National Institutes of Health (NIH publication no 85–23, revised 1996)

Results
Following in vivo ischemia-reperfusion, infarct size was smaller in Arg 1-KO mice than in WT mice (Fig. A). A similar degree of infarct size reduction was obtained by i.v. administration of an arginase inhibitor in WT mice. The cardioprotective effect observed in Arg 1-KO mice was abolished by the NOS inhibitor L-NMMA (Fig. A). In isolated buffer-perfused hearts, there was no difference in the post-ischemic recovery of LVDP between Arg 1-KO and WT hearts. When erythrocytes from Arg 1-KO mice were administrated to isolated WT mouse hearts, the post-ischemic recovery of LVDP was significantly improved compared to hearts given erythrocytes from WT mice. Also, the cardioprotective effect of erythrocytes from Arg 1-KO mice was abolished by pre-incubation of the erythrocytes with the NOS inhibitor L-NAME (Fig. B) or the inhibitor of soluble guanylyl cyclase ODQ (Fig. C).

Conclusion
Arginase 1 in erythrocyte plays an important role in regulating cardioprotection mediated via the NO-soluble guanylyl cyclase pathway.

Funding Acknowledgement
Type of funding sources: Foundation. Main funding source(s): Swedish Heart and Lung Foundation (20190266),The Swedish Research Council (2020-01372)
Evaluation of the direct protective effects of Canagliflozin on the Isoproterenol-induced cell injury in rat cardiomyocytes
Authors: Murayama Y , Kitasato L , Ishizue N , Suzuki M , Mitani Y , Saito D , Matsuura G , Sato T , Kobayashi S , Nakamura H , Oikawa J , Kishihara J , Fukaya H , Niwano S , Ako J 
Published: October 2022

Abstract

Background
Sodium-glucose cotransporter-2 (SGLT2) inhibitors are agents that act by inhibiting glucose and sodium reabsorption in the proximal renal tubule which promotes urinary glucose excretion. More recently, significant benefit data of SGLT2 inhibitors in patients with heart failure, independent of the presence of type 2 diabetes has been reported. We have previously demonstrated that Canagliflozin (Cana), a SGLT2 inhibitor, reduced the ventricular effective refractory period in isoproterenol (ISP)-induced myocardial injury rat model accompanied with the suppression of reactive oxygen species and the elevation of ketone bodies, suggesting the effect of Cana on electrical cardiac remodeling. The direct effect of Cana to the cardiomyocytes and its underlying molecular mechanism was remained to be clarified. We therefore established an ISP-induced neonatal rat ventricular cardiomyocyte (NRVCM) in vitro model, pretreated with Cana and/or ketone bodies.

Methods
Primary NRVCM were isolated from Wistar rats, were pretreated by Cana with or without βOHB (the most abundant ketone body in circulation), followed by a stimulation of ISP (10μM). Cells without drug or ketone body pretreatment were used as control. We then analyzed its effect on cell viability, apoptosis, and mitochondrial membrane potential using MTT assay, TUNEL assay, and mitochondrial membrane potential assay, respectively. MTT assay was also performed with or without PI3k inhibitor, LY294002. The end-labeling of DNA fragmentation were labelled with FITC, followed by the nuclei counterstain with DAPI and were observed with confocal microscope. The apoptotic index was defined as the percentage of TUNEL positive cells / total nuclei.

Results
Cana rescued the reduction of NRVCM cell viability induced by ISP stimulation for 24 hours which was inhibited by LY294002 compared to cells without pretreatment. Interestingly, pretreatment of βOHB with or without Cana improved also the NRCVM cell viability whereas there was no significant difference between these two conditions or with cells treated with Cana only, suggesting the direct protective effect of Cana. In 48 hours of ISP stimulation, the apoptotic index intends to decrease in Cana and/or βOHB compared to cells without pretreatment (Figure 1). Although the mitochondrial function was maintained in Cana-pretreated cells compared to cells without pretreatment, there was no significant difference in βOHB-pretreated cells.

Conclusions
Cana has a direct protective effect on cardiomyocytes cell viability, apoptosis as well as the mitochondrial function impaired by ISP through the cell survival signaling PI3K/Akt pathway. This brings a new insight to the therapeutic target of cardiovascular disease.

Funding Acknowledgement
Type of funding sources: None.
Metabolic modulation as a common adaptive mechanism in patients with different subtypes of aortic valve stenosis
Authors: Bengel P , Beuthner B E , Topci R , Pietzner M , Hasenfuss G , Toischer K , Schnelle M 
Published: October 2022

Abstract

Background
Aortic valve stenosis (AS) is a rapidly growing global health problem due to aging and population growth. If treatment by aortic valve replacement (AVR) is delayed, this leads to poor recovery of cardiac function and marked increase of mortality. In conditions of AS or heart failure a cardiac remodelling occurs including a change in cardiac substrate utilization. However, it is difficult to determine the stage of AS-induced cardiac remodelling and therefore the reversibility of this changes after AVR. As cardiac metabolism might be therapeutic target for patients not recovering after valve replacement a better understanding of the metabolic remodelling in different AS subtypes is necessary. Metabolomics constitute a potent screening tool for defining changes in global and cardiac-specific metabolism in cardiovascular disease.

Methods/Results
Serum metabolomic profiling for 1293 metabolites was performed in serum samples of 40 AS-patients and 10 healthy controls using Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectroscopy. AS-patients were divided in four groups (10 patients/group) with respect to ejection fraction (EF, normal/reduced) and aortic valve gradient (&gt; or &lt;40 mmHg). Principal component analysis revealed a clear difference of metabolic profiles in AS-patients vs controls. However, less separation between AS-subtypes could be detected. A Random Forest Analysis comparing all AS-patients to healthy controls resulted in a predictive accuracy of 94%. In AS-patients we observed an increase of acyl carnitines compared to control indicating an alteration of myocardial free fatty acid oxidation. Moreover, we detected a higher ketone body concentrations in AS-patients that could serve as an alternative fuel source for the heart. Interestingly, no differences between the AS subgroups could be detected indicating that changes occur independently from EF and AS-gradient. Additionally, several compounds involved in nitrogen balance were increased in AS-patients while numerous amino acids were decreased, possibly also due to alternative energy production. Increased circulating heme catabolites have been associated with heart failure. Here, we found increased heme catabolites only in patients with low EF and high-gradient with unclear significance.

Conclusion
In summary, our study indicates a shift of cardiac substrate utilization in patients with AS from free fatty acid oxidation to alternative substrates like ketone bodies and amino acids. As no differences between AS subtypes were observed, this metabolic remodelling may occur as an adaptive mechanism independent from EF and AS-gradient in patients with severe AS. Since our study was conducted by an unspecific approach with a small sample size, further investigation is necessary for a better understanding of the specific myocardial metabolic changes in AS patients.

Funding Acknowledgement
Type of funding sources: None.
Association of heart failure and liver T1 mapping in cardiac magnetic resonance imaging
Authors: Bartkowiak J , Peters A , Seitz R , Bernhard B , Praz F , Graeni C , Brugger N , Huber A 
Published: October 2022

Abstract

Background
Heart failure culminates in liver congestion. As the liver can be assessed by cardiac magnetic resonance T1 mapping sequences, it represents a promising imaging biomarker for heart failure.

Objectives
To evaluate the association between heart failure and magnetic resonance liver T1 mapping, as a non-invasive imaging surrogate of liver congestion.

Methods
Patients with cardiac magnetic resonance including T1 mapping sequences on a single 1.5T scanner were consecutively included between 01/2017 and 12/2019. Liver T1 was measured in the left lobe, right lobe and caudate lobe on short axis view and in the liver dome on four chamber view. Echocardiographic and laboratory parameters were analyzed within 90 days of the cardiac magnetic resonance exam. Left ventricular filling pressures were assessed according to the European Association of Cardiovascular Imaging guidelines [1]. Liver T1 and echocardiographic parameters were compared between patients with and without elevated NT-proBNP levels (&gt;125 pg/ml) using a Mann-Whitney U test. A multivariate logistic regression model was used to correct for age, sex, body mass index, left ventricular ejection fraction and the presence of atrial fibrillation.

Results
A total of 397 patients were included (median age 56, 127 females), of whom 138 patients (35%) presented with elevated NT-proBNP levels. Patients with elevated NT-proBNP levels had a larger indexed end-diastolic left ventricular volume (92 vs. 81 ml/m2, p&lt;0.001), lower left ventricular ejection fraction (60 vs. 50%, p&lt;0.001) and a higher E/E' ratio (11 vs. 8, p&lt;0.001). Liver T1 was higher in patients with elevated NT-proBNP in the right liver lobe (670 vs. 596 ms, p&lt;0.001) and the caudate lobe (664 vs. 598 ms, p&lt;0.001), but not in the left liver lobe (571 vs. 568 ms, p=0.068) and in the liver dome (590 vs. 560 ms, p=0.1). Echocardiographic evaluation showed similar results with significant difference in T1 times between patients with elevated and non-elevated left ventricular filling pressures in caudate and right liver lobe. Liver T1 retained its predictive value when corrected for age, left ventricular ejection fraction and the presence of atrial fibrillation, when measured in the caudate lobe (adjusted odds ratio 1.013, 95% confidence interval 1.004–1.023, p=0.005) and in the right lobe (adjusted odds ratio 1.012, 95% confidence interval 1.003–1.021, p=0.009).

Conclusions
Elevated liver T1 in cardiac magnetic resonance imaging is associated with heart failure and represents an independent non-invasive imaging surrogate for liver congestion.

Funding Acknowledgement
Type of funding sources: None.
The interaction of receptor-type protein tyrosine phosphatases sigma and zeta1 controls cardiac fibroblast migration
Authors: Hasselbach L , Weidner J , Elsaesser A , Theilmeier G 
Published: October 2022

Abstract

Background
Among cardiovascular diseases as a major health burden heart failure (HF) plays a central role. Our screening of patients with HF either from ischemic – or dilatative cardiomyopathy has shown that receptor-type protein tyrosine phosphatase sigma (PTPRσ) and zeta1 (PTPRz1) are upregulated compared to healthy hearts. Inhibition of PTPRσ is known to be necessary for autonomic reinnervation after myocardial infarction [1] and for various functions in the nervous system [2]. Most recently the loss of PTPRz1 in knockout-mice has been shown to lead to impaired morphogenesis with postnatal systolic and diastolic heart failure [3].

Purpose
A crucial step in myocardial remodeling and the development of HF is fibroblast migration into the wound, where they differentiate into myofibroblasts, producing extracellular matrix proteins and forming the scar. Up to now no information is available on the role of PTPRσ and PTPRz1 in fibroblast migration and myocardial remodeling.

Methods
Neonatal cardiac fibroblasts are transfected with either scrambled-, PTPRσ-, PTPRz1-siRNA or a combination thereof. A scratch wound is inflicted at confluency of the cells. The number of migrated cells, relative to the control, is determined microscopically after 48 hours. Transfected fibroblasts are seeded into transwells to examine their transmigration. After 48 hours the number of transmigrated cells, relative to the control, is determined after DAPI staining. N=4, statistical analysis is performed using Kruskal-Wallis Test with Dunn's multiple comparison.

Results
In the scratch assay a PTPRz1 knockdown resulted in a significant increase in migrating cells (1 vs. 1,355±0,1144, p=0,0265). This promigratory effect is not present in PTPRσ knockdown cells, independent of the PTPRz1 expression (1 vs. 1,032±0,1654 and 1 vs. 1,073±0,08597, both p&gt;0,9999). In transmigration there is a fourfold increase in transmigrated cells after PTPRz1 knockdown (1 vs 4,046±0,4865, p=0,05). Like in migration this effect is reversed after downregulation of PTPRσ (1 vs 0,9834±0,3844 and 1 vs. 1,345±0,6584, both p&gt;0,9999).

Conclusion
PTPRσ and PTPRz1 are differentially regulated during the pathogenesis of heart failure. While a knockdown of PTPRz1 leads to an increase in fibroblast migration and transmigration, downregulation of PTPRσ inhibits this effect. These results indicate an antimigratory role for PTPRz1. We hypothesize that PTPRσ and PTPRz1 interact through shared intracellular effector molecules, affecting fibroblast migration, an important step in myocardial remodeling and the development of HF. Further investigations will be conducted to identify these shared effector molecules of PTPRσ and PTPRz1 to find a way to influence heart failure through regulation of receptor-type protein tyrosine phosphatases.

Funding Acknowledgement
Type of funding sources: Public Institution(s). Main funding source(s): Carl von Ossietzky University Oldenburg
Decrease of RNA editing in the failing heart leads to induction of circRNAs
Authors: Kokot K , Kneuer J , John D , Rebs S , Mueller M , Haas J , Thiele H , Mueller O J , Hille S , Leuschner F , Dimmeler S , Streckfuss-Boemeke K , Meder B , Laufs U , Boeckel J N 
Published: October 2022

Abstract

Background and purpose
Adenosine-to-Inosine (A-to-I) RNA editing is a post-transcriptional modification process that affects the secondary structure of RNAs. Changes in RNA editing have been associated with human diseases. We therefore aimed to analyze editing in the healthy and failing human heart.

Methods and results
Transcriptome sequencing of human heart samples of heart failure (HF) patients (n=20) and controls (n=10) revealed A-to-I editing as the major type of editing (&gt;80%). In HF patients, RNA editing was reduced, which was primarily attributable to Alu elements in introns of protein-coding genes. We identified 166 upregulated circRNAs in HF, with the majority showing reduced RNA editing in their parental host gene (88.3%). CircRNA expression did not correlate with their corresponding host gene (R=0.07, P&lt;0.05), suggesting that an alternative splicing mechanism gives rise to the elevated circRNA levels in HF. The RNA editing enzyme ADAR2, which binds to RNA regions that are edited from adenosine to inosine, was decreased in failing human hearts (−68.2%). In vitro, reduction of ADAR2 increased circRNA levels suggesting a causal effect of reduced ADAR2 levels on increased circRNAs in the failing human heart. To gain mechanistic insight, we examined the formation of circRNAs on one exemplary candidate. AKAP13 was among the top edited mRNAs in the human heart and gave rise to a circular transcript, which was elevated in HF. ADAR2 reduced the formation of double-stranded structures in AKAP13 pre-mRNA, thereby reducing the stability of Alu elements and the circularization of the resulting circRNA. Overexpression of circAKAP13 impaired the sarcomere regularity of human induced pluripotent stem cell-derived cardiomyocytes (−31.0%).

Conclusion
Our study shows that ADAR2 mediates A-to-I RNA editing in the human heart. We describe an alternative splicing mechanism of circRNAs in the human heart. In the healthy human heart, A-to-I RNA editing represses the formation of dsRNA structures of Alu elements thereby favoring linear mRNA splicing. Our results contribute to a better mechanistic understanding into the human-specific regulation of circRNA formation and are relevant to diseases with reduced RNA editing and increased circRNA levels.

Funding Acknowledgement
Type of funding sources: None.
Golgi Apparatus fragmentation in dilated cardiomyopathy and its relationship with the alteration of vesicular transport
Authors: Gimenez-Escamilla I , Perez-Carrillo L , Portoles M , Martinez-Dolz L , Tarazon E , Rosello-Lleti E 
Published: October 2022

Abstract

Background
The Golgi Apparatus (GA) is an important membrane-bound organelle implied in many physiological events, as trafficking, processing and sorting of newly membrane and secretory proteins and lipids. Nevertheless, these functions can be dysregulated in a diversity of pathologies due to the alteration of the GA morphology, such as cardiovascular diseases. Previously, we described in dilated cardiomyopathy (DCM) alterations in shape and size of the secretion vesicles of GA that was related to a worse functional situation. The patients had smaller, more ellipsoidal and more numerous vesicles with a higher content of natriuretic peptides (1). This situation can be related with Golgi fragmentation, a status characterized by the presence of a dispersed GA both in physiological and pathophysiological conditions (2). However, a greater understanding of Golgi fragmentation in DCM is necessary.

Purpose
We attempted to analyse the components of the vesicular Golgi transport and the Golgi fragmentation in cardiac tissue samples from DCM patients, paying special attention to GM130, as one of the main molecules related with the Golgi fragmentation.

Methods
We analysed vesicular Golgi transport genes in human hearts by RNA-sequencing in 13 samples from DCM patients and 10 control hearts (CNT), and the miRNAs that regulate their expression by ncRNA sequencing (DCM, n=20; and CNT, n=8). Finally, we investigated changes in the protein levels of GM130 and its phosphorylated state (pGM130) by western blot with 22 DCM and 6 CNT samples in total.

Results
We found 134 differentially expressed genes related to the GA, and 15 of them were involved in the secretion of Golgi vesicles. Among these molecules, VAMP4, a v-SNARE related with the Golgi fragmentation, is found to be downregulated (−1.27-Fold; P&lt;0.05). Moreover, we have observed a downregulation in the expression of GOLGA2, the gene that encodes GM130 (−1.24; P&lt;0.05). Furthermore, its regulator, hsa-miR-17-5p (−1.42; P&lt;0.01) was also downregulated. In this sense, we have found no changes in GM130 protein levels between DCM patients and CNT group. In contrast, pGM130, molecule that it has been used as a biomarker of Golgi fragmentation, was overexpressed in DCM patients (1.19; P&lt;0.05).

Conclusion
We found a deregulation of genes related to the vesicle secretion in the GA, which together with the changes in vesicular morphology previously observed, suggests an alteration in the rate of secretion in response to the needs of the DCM patients. In addition, the increase in the phosphorylated protein GM130 suggests the presence of fragmentation in DCM patients that could be related to the alteration in vesicular transport.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Institute of Health Carlos III European Regional Development Fund (ERDF)