bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 292: Brain Derived Neurotrophic Factor Induced Upregulation Of Peroxisome Proliferator-activated Receptor Gamma Coactivator 1-alpha Signaling Prevents Hearts From Heart Failure Progression Against Pressure Overload
Authors: Feng Ning , Zhu Guangshuo , Sivakumaran vidhya , Zhang Manling , Bedja Djahida , Takimoto Eiki , Paolocci Nazareno
Published: July 2021

Background:
The heart is under the influence of neurotrophins (NTs) secreted from peripheral sympathetic nerves, including brain derived neurotrophic factor (BDNF). BDNF is indispensible for cardiac development and vascular wall integrity. Yet, whether BDNF signaling plays a role in governing cardiac function in response to stress is unclear.

Hypothesis:
BDNF signaling contributes to maintain proper cardiac structure/function in pressure overloaded mice.

Results:
BDNF expression is markedly down-regulated in hearts subjected to transverse aortic constriction (TAC). Cardiac specific over-expression of BDNF (BDNF-TG) or administration of a BDNF-mimetic agonist (LM22A-4) preserved cardiac function against pressure overload. In contrast, cardiac-selective deletion of the BDNF receptor, Tropomyosin related kinase receptor B (TrkB), further exacerbated heart failure. In neurons, BDNF up-regulates Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α) that regulates energy metabolism and mitochondrial function/biogenesis. Oxidative stress is a major negative modulator of PGC-1a expression/activity. Exposing neonatal rat ventricular myocytes (NRVMs) to hydrogen peroxide downregulated PGC-1α, and BDNF restored it to normal levels, with a concomitant up-regulation of downstream genes involved in both mitochondrial biogenesis and oxidative stress, resulting in attenuated ROS production and increased mitochondrial biogenesis. Consistent with the cultured myocyte findings, PGC-1α and downstream genes were up-regulated in BDNF-TG mice subjected to TAC, associated with attenuated oxidative stress and improved mitochondrial biogenesis; whereas TrkB-/- mice subjected to TAC displayed further decreased PGC-1α expression with worsened oxidative stress and impaired mitochondrial biogenesis.

Conclusion:
Our data show that BDNF confers protection against pressure overload via enhanced PGC-1α signaling that in turn prevents oxidative stress and improves mitochondrial biogenesis. Our data suggest BDNF/trkB is a promising new therapeutic avenue to prevent or retard heart failure.
Abstract 310: Production of Basal Lamina Collagen IV by Cardiac Fibroblasts in 3-Dimensional Cultures
Authors: Bradshaw Amy , Trombetta eSilva Jessica , Eadie Erik , Borg Thomas K
Published: July 2021

Cardiac fibroblasts are generally considered the primary cell type that controls extracellular matrix homeostasis in the heart. Distinct changes in amounts and composition of extracellular matrix occur from birth to old age. Accordingly, age-dependent alterations in cardiac extracellular matrix are an important factor governing response to injury and pathological remodeling. Whereas cardiac myocytes are surrounded by a basal lamina, cardiac fibroblasts do not assemble a cell-adjacent basal lamina. Evidence is presented that in addition to fibrillar collagen production, cardiac fibroblasts are also the primary cell type responsible for the production of collagen IV. First, patterns and abundance of collagen IV in murine heart was established in sections from neonate, adult, and aged mice. Second, production of collagen IV by fibroblasts grown in 3-D fibrin gels was assessed by confocal microscopy and quantification by immmunoblot analysis. Finally, co-cultures of cardiac fibroblasts with myocytes were performed to show that fibroblasts are the primary cell type producing collagen IV under these conditions. The basal lamina of the myocytes plays a critical role in aligning and tethering myocytes together as well as making connections to the interstitial collagen fibers of the heart. Hence, production of collagen IV by cardiac fibroblasts would provide a mechanism by which cardiac fibroblasts assist in aligning and securing cardiac myocyte alignment and structural integrity via basal lamina production.
Abstract 315: The Role of Mixed Lineage Kinase 3 in Inflammatory Cell-Fibroblast Communication
Authors: Schulz Emily M , Dixon Allison E , Burhans Michael S , Nieman Michelle L , Lorenz John N , Goodfellow Val , Gelbard Harris A , Dewhurst Stephen , Blaxall Burns C
Published: July 2021

Mixed lineage kinase 3 (MLK3) is a ubiquitously expressed pro-inflammatory, pro-apoptotic mitogen activated protein kinase kinase kinase (MAP3K). MLK3 is a key regulator of the p38 and c-jun terminal kinase (JNK) pathways and has been studied in cancer and neurodegenerative disease. Although the p38 and JNK pathways have been studied in the cardiac function and disease, little is known regarding the role of MLK3 in the heart. Studies in our laboratory have indicated that MLK3 RNA is highly expressed in macrophages, cardiomyocytes and cardiac fibroblasts, suggesting an important role in cardiac function. Recently published work has indicated that MLK3 plays an important role in inflammatory cell motility, leading us to hypothesize that MLK3 is involved in inflammatory cell-fibroblast communication during cardiac disease. Knockout (KO) or inhibition of MLK3 using the novel small molecule inhibitor URMC-099 does not significantly affect heart rate, mean arterial pressure, systolic pressure, minimum or maximum dp/dt compared to wild type (WT) controls as measured by invasive hemodynamics at 3 months of age. Echocardiographic analysis indicates that MLK3 KO or inhibition does not affect cardiac architecture or cardiac function, indicated by fractional shortening or ejection fraction. However, upon transaortic constriction (TAC), MLK3 KO and URMC-099 treatment results in decreases in Mac-3 positive staining at 3 and 7 days post-TAC as well as decreases in CD-45 staining 7 days post-TAC compared to WT TAC operated, vehicle treated controls, suggesting that MLK3 KO and drug treatment may attenuate the early inflammatory response after TAC. Studies examining the relationship between the MLK3 mediated inflammatory response and subsequent fibrosis and cardiac dysfunction post-TAC are currently ongoing.
Abstract 336: Cardiac Function Improvement in Infarcted Rats Treated with an Association of N-acetylcysteine and Deferoxamine
Authors: Andrades Michael , Phaelante Amanda , Olsen Virgílio , Tobar Santiago , Lopes Amanda , Martinelli Nidiane , Cohen Carolina , Dal-Pizzol Felipe , Biolo Andreia , Rohde Luis , Clausell Nadine
Published: July 2021

Acute myocardial infarction (AMI) is followed by free radicals generation, which is central in cardiac remodeling. N-acetylcysteine (NAC) is an antioxidant that may have pro-oxidant activity in presence of iron ions. Thus, the association with an iron chelator might improve NAC antioxidant potential. Our aim was to test the association of NAC and an iron chelator (deferoxamine - DFX) on cardiac remodeling in a rodent model of AMI. To this end, Male Wistar rats (60 days old) were subjected to a sham surgery or subjected to myocardial infarcted by the occlusion of left ventricular descending artery. Twelve hours after, AMI was confirmed by cTnI evaluation and the animals were randomized in the following treatments: vehicle, NAC (25 mg/kg for 28 days), DFX (40 mg/kg for 7 days), or NAC plus DFX (NAC 25 mg/kg for 28 days plus DFX 40 mg/kg for 7 days). All animals were followed for 28 days. AMI induced an increase in total plasma iron levels at 7 days after the procedure and all treatments were able to decrease iron concentration. NAC/DFX was able to keep iron levels low up to 28 days. Morphofunctional assessments were made serially by echocardiography. Animals treated with NAC/DFX showed an increase in ejection fraction at 28 days when compared with vehicle group (45% ± 11% vs. 35% ± 9%,respectively; p=0.03). On histological analysis (at 28 days), NAC/DFX treated rats showed decreased oxidative stress (immunohistochemistry anti-4-hydroxynonenal, a side product of lipid peroxidation) when comparing with vehicle group (p=0.059). In conclusion, the association of NAC/DFX was able to attenuate chamber remodeling and improved left ventricle function in an animal model of AMI, whereas either NAC or DFX had no effect when given alone. The likely participation of iron and free radicals can be suggested, but further studies are necessary.
Abstract 337: The Cardiolipin-targeting Peptide Bendavia Preserves Post-ischemic Mitochondrial Energetics by Sustaining Respiratory Supercomplexes
Authors: Brown David A , Moukdar Fatiha , Alleman Rick J , Lark Daniel S , Neufer P D , Shaikh Saame R
Published: July 2021

Bendavia is a mitochondria-targeting peptide currently being tested in the EMBRACE-STEMI trial for reducing injury during acute coronary syndromes. We previously showed that the cardioprotective effects of Bendavia involved improving cardiolipin-dependent mitochondrial membrane fluidity. As membrane fluidity influences the ability of proteins to assemble, we hypothesized that a consequence of augmented membrane fluidity would be higher expression of mitochondrial respiratory supercomplexes. Rat hearts (n=42) were subjected to ischemia-reperfusion (I/R) with or without 1nM Bendavia perfusion beginning at the onset of reperfusion. Left ventricular tissue was split into one of two study arms: 1. Supercomplex expression using blue-native gel electrophoresis (BN-PAGE), or 2. High-resolution respirometry using permeabilized ventricular fibers. For BN-PAGE studies, respiratory supercomplex bands were decreased with I/R, and restored with Bendavia (see figure). High-resolution respirometry studies indicated suppressed Complex I-dependent respiration after I/R (208±19 v 42±9 pmol O2/mg*s in control v I/R, respectively; P<0.05). Complex II-dependent respiration was also lower (753±41 v 168±13 pmol/mg*s in control versus I/R; P<0.05). Perfusion with Bendavia during reperfusion significantly increased Complexes I- (100±13pmol O2/mg*s) and II-dependent (334±63 pmol O2/mg*s) respiration (P<0.05 versus untreated IR for both). Taken together, these data suggest that Bendavia’s protective mechanism of action involves preserving supercomplex-dependent mitochondrial function during cardiac reperfusion.
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 347: Glutathione-S-Transferase P Regulates Bone Marrow Derived Endothelial Progenitor Cell (EPC) Function and Neovascularization in the Infarcted Heart
Authors: Zhou Guihua , Zhong Hai , Wu Yixin , Sun Chiao-Wang , Townes Timothy M , Prabhu Sumanth D
Published: July 2021

Glutathione-S-transferase P (GSTP) modulates proliferation of bone marrow (BM) myeloid progenitors via non-catalytic inhibition of c-Jun N-terminal kinase (JNK); however, its effects on BM-derived EPCs are unknown. We hypothesized that GSTP supports EPC mobilization while suppressing inflammatory cells, thereby promoting tissue neovascularization. We generated chimeric mice using BM-ablated wild-type (WT) mice reconstituted with either GSTP-/- (GSTP-/-c) or WT (WTc) BM. GSTP-/-c and WTc mice underwent coronary ligation or sham operation (n = 8-15/group). Compared to WTc sham, 4 w after surgery, WTc HF mice exhibited significant (p < 0.05): LV dilatation, dysfunction, and fibrosis; increased mortality; and augmented circulating pro-inflammatory CD11b+Ly6Chi monocytes, but comparable circulating CD34+VEGFR2+ EPCs. In contrast, compared to WTc HF, GSTP-/-c HF hearts had significant (p < 0.01): 1) worsening of LV dilatation (LVEDV 118 ± 30 vs 88 ± 13 μL), dysfunction (LVEF 21 ± 4 vs 32 ± 9 %), wall thinning (anterior wall thickness 0.41 ± 0.06 vs 0.49 ± 0.1 mm), and LV hypertrophy (LV/tibia length 4.9 ± 0.5 vs 4.5 ± 0.6 mg/mm); 2) increased remote zone fibrosis by trichrome staining (1.3 ± 0.2 vs 0.61 ± 0.3 %); 3) reduced capillary density (476 ± 60 vs 544 ± 37 capillary/mm2) and increased capillary area (14 ± 1.1 vs 12 ± 1.2 μm2); 4) diminished gene expression of VEGF A, VEGF B, and VEGF C; 5) and increased IL-1β, IL-6 gene expression. GSTP-/-c mice also exhibited (p < 0.01) increased BM JNK activation, reduced circulating EPCs (0.18±0.07 vs 0.24±0.06%), increased CD11b+Ly6Chi monocytes (2.25±0.5 vs 1.8±0.6%), but comparable anti-inflammatory CD11b+Ly6Clow monocytes at baseline as compared with WTc mice. Moreover, at 3 and 7 d after ligation, GSTP-/-c HF mice exhibited fewer circulating EPCs and anti-inflammatory monocytes, and significantly higher pro-inflammatory monocytes as compared with WTc HF mice. We conclude that GSTP promotes EPC and reparative monocyte mobilization, thereby improving angiogenic gene expression, neovascularization and LV remodeling after myocardial infarction. This suggests that GSTP polymorphisms can impact cardiac reparative capacity in humans, and that enhancing GSTP function after infarction may yield therapeutic benefit.
Abstract 351: Biophysical Cues From Nano Size Pillar Affect Character Of Human Endothelial Colony Forming Cells
Authors: Cui Long-Hui , Kim Jung-Suk , Joo Hyung Joon , Choi Seung-Cheol , Kim Jong-Ho , Seo Ha-Rim , Park Chi-Yeon , Choi Ji-Hyun , Hong Soon Jun , Lee Kyu-Back , Lim Do-Sun
Published: July 2021

Background:
Recently, biophysical cues from nano patterned surface received extra attention. Because, numerous cells in the human body is surrounded by the nano-microenvironment. Especially for the live cells biophysical cues from nanotopography is an important factor for cell motility and pathophysiology. Human Endothelial Colony Forming Cells (hECFCs) is human peripheral blood mononuclear cells (PBMNCs) derived endothelial cell like cells which related with various disease occurrence.

Methods:
To investigate the effect of biophysical cues from nano size pillar surface, we use the novel nano size pillar surface culture dish in this experiment. The diameter size of nano pillar is 120nm to 360nm and we separate the gradient topography as High (280nm-360nm), Middle (200nm-280nm) and Low (120nm-200nm) respectively. hECFCs was derived from human peripheral blood mononuclear cells (hPBMNCs) and cultured with EGM2-MV endothelial medium.

Results:
Attachment of hECFCs was decreased on the High (280nm-360nm) nano size pillar area. But, proliferation and apoptosis of hECFCs on the nano size pillar surface has no significant difference with hECFCs on the flat pattern. However, single cell morphology of hECFCs on the nano size pillar surface was distinct compared with hECFCs on the flat pattern. Finally, gene expression level of ROCK, Rho and Integrin family has changed on the nano size pillar surface.

Conclusion:
In this study we find that biophysical cues from nano size pillar surface can affect single cell morphology of hECFC and gene expression level. Further, through these several results we can know that ROCK family are related with biophysical cues from nanotopography and nano pillar diameter size can affect the optimal culture condition for hECFC.
Abstract 356: KChIP2 Mediates Ion Channel Dysregulation by Novel Transcriptional Regulation of miR-34s
Authors: Nassal Drew , Liu Haiyan , Wan Xiaoping , Ramirez-Navarro Angelina , Ficker Eckhard , Deschenes Isabelle
Published: July 2021

Introduction:
Cardiac ion channel dysregulation is a hallmark of heart failure. Consistently, the disease yields dramatic decline in Ito through loss in Kv4 and its auxiliary partner KChIP2. Notably, transcriptional changes in heart failure can be elicited through KChIP2 silencing without disease signaling, suggesting potential transcriptional capacity for KChIP2. Further, disparity between resulting transcript and protein patterns suggests a mechanism compatible with modified miRNA activity. Considering other members of the KChIP family behave as transcriptional repressors, we hypothesize that KChIP2 regulates discrete miRNAs which in turn regulate cardiac excitability.

Methods and Results:
A miRNA microarray was conducted on neonatal rat ventricular myocytes (NRVM) following in vitro silencing of KChIP2 by siRNA, identifying the miR-34 family as potential transcriptional targets of KChIP2. Regulation, confirmed by quantitative PCR, showed reduction in miR-34a/b/c when over-expressing KChIP2 and increase following silencing. Luciferase assays were performed on the cloned promoter for miR-34b/c which reinforced direct KChIP2 repression on the miR-34b/c promoter. Furthermore, chromatin immunoprecipitation followed by PCR identified physical interaction of KChIP2 to the promoter site. Previous studies show modified expression of KChIP2 can lead to changes in several ion channel subunits. Therefore, we investigated if this was the consequence of KChIP2 regulation via miR-34. miR-34a/b/c precursors were expressed in NRVM which reduced transcript levels of Nav1.5 and Navβ1, and reduced protein levels for Kv4.3. Reflecting these changes, peak INa was reduced following miR precursor treatment. NRVMs were exposed to 100 μM phenylephrine for 48 hrs, significantly reducing KChIP2, Nav1.5, Navβ1, and Kv4.3, while elevating miR-34b/c. Returning KChIP2 expression by adenovirus normalized these changes back towards baseline, implicating the physiologic relevance of this pathway.

Conclusion:
These observations describe a novel mechanism where KChIP2 regulates a host of cardiac genes through transcriptional control of miRNAs, potentially explaining electrical remodeling observed in disease states where KChIP2 is reduced.
Abstract 360: MiR-133 Modulates the Beta1-Adrenergic Receptor Transduction Cascade
Authors: Castaldi Alessandra , Zaglia Tania , Di Mauro Vittoria , Carullo Pierluigi , Viggiani Giacomo , Borile Giulia , Di Stefano Barbara , Schiattarella Gabriele Giacomo , Gualazzi Maria Giovanna , Elia Leonardo , Stirparo Giuliano Giuseppe , Pironti Gianluigi , Kunderfranco Paolo , Colorito Maria Luisa , Esposito Giovanni , Bang Marie-Louise , Mongillo Marco , Condorelli Gianluigi , Catalucci Daniele
Published: July 2021

Rationale:
The sympathetic nervous system plays a fundamental role in the regulation of myocardial function. During chronic pressure overload, over-activation of the sympathetic nervous system induces the release of catecholamines, which activate β-adrenergic receptors (βARs) in cardiomyocytes (CMs) and lead to increased heart rate and cardiac contractility. However, chronic stimulation of βARs leads to impaired cardiac function and β-blockers are widely used as therapeutic agents for the treatment of cardiac disease. MiR-133 is highly expressed in the myocardium and is involved in controlling cardiac function through regulation of mRNA translation/stability.

Objective:
To determine whether miR-133 affects βAR signaling during progression to heart failure.

Methods and Results:
Based on bioinformatic analysis, β1AR and other components of the β1AR signal transduction cascade, including adenylate cyclase VI and the catalytic subunit of the cAMP-dependent protein kinase A (PKA), were predicted as direct targets of miR-133 and subsequently validated by experimental studies. Consistently, cAMP accumulation and activation of downstream targets were repressed by miR-133 overexpression in both neonatal and adult CMs following selective β1AR stimulation. Furthermore, gain- and loss-of-function studies of miR-133 revealed its role in counteracting the deleterious apoptotic effects caused by chronic β1AR stimulation. This was confirmed in vivo using a novel cardiacspecific TetON-miR-133 inducible transgenic mouse model (Tg133). When subjected to transaortic constriction, Tg133 mice maintained cardiac performance and showed attenuated apoptosis and reduced fibrosis compared to control mice.

Conclusions:
MiR-133 controls multiple components of the β1AR transduction cascade and is cardioprotective during heart failure.
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 57: Impaired Aldehyde Dehydrogenase 2 Activity Contributes To Inhibition Of Mitochondrial Respiration In Hyperglycemic Rats
Authors: Mali Vishal , Deshpande Mandar , Xu Jiang , Giri Shailendra , Yang Xiao-Ping , Palaniyandi Suresh
Published: July 2021

Aldehyde dehydrogenase (ALDH) 2 is a mitochondrial isozyme of the heart involved in the metabolism of toxic aldehydes produced from oxidative stress. A decrease in ALDH2 levels and activity was reported in the hearts of experimental hyperglycemia along with an increase in 4-hydroxy-2-nonenal (4HNE). 4HNE is produced in the mitochondria upon lipid peroxidation and known to form adduct with mitochondrial proteins. We hypothesize that reduced ALDH2 activity impairs mitochondrial respiration due to 4HNE adducts formation, ultimately resulting in cardiac damage in hyperglycemia. A single dose (65 mg/kg; i.p.) of streptozotocin in rats resulted in hyperglycemia with a blood glucose level of 443 ± 9 mg/dl versus 121 ± 7 mg/dl in control animals, p<0.0001. N=7-11 in both groups. After 6 months of hyperglycemia, heart function was recorded and the rats were sacrificed. Increases in cardiomyocyte cross sectional area (446 ± 32 μm
2
Vs
221 ± 10 μm
2
; p<0.0001) indicated cardiac hypertrophy in diabetic rats. Both diastolic and systolic dysfunctions were recorded with diabetic rats compared to controls. For instance, % fractional shortening was lower in diabetic group versus control; (p<0.0001). Most importantly, myocardial ALDH2 activity and levels were reduced and immunostaining for 4HNE protein adducts was increased in diabetic hearts compared to controls. The mitochondrial oxygen consumption rate (OCR), an index of mitochondrial respiration, was decreased in mitochondria isolated from diabetic hearts compared to controls (p<0.0001). To check the direct effect of 4HNE and ALDH2 inhibition, we treated H9C2 cardiomyocytes with 4HNE and disufiram, an ALDH inhibitor, respectively, which reduced mitochondrial respiration (p<0.0001) and cell viability (p<0.0001) along with reduced ALDH2 activity and increased 4HNE adducts formation. We conclude that chronic hyperglycemia-induced 4HNE accumulation due to low ALDH2 activity in the heart leads to defective mitochondrial respiration and cardiac damage and dysfunction.
Abstract 59: A Protective Role Of Adenine Nucleotide Translocator 1 In The Inflammatory Response Following Myocardial Infarction
Authors: Pan Shi , Wang Nadan , Sheu Shey-Shing
Published: July 2021

Background:
Inflammation following myocardial infarction (MI) contributes significantly to the pathogenesis of heart failure. Although the initial stage of inflammatory response is necessary for the repair and healing of myocardium, excessive inflammation post MI causes adverse remodeling leading to heart failure. Recent studies suggest that mitochondrial dysfunction plays an important role in inflammation. However, the molecular target in cardiac mitochondria and the mechanisms of action remain unclear. We hypothesized that mitochondrial ADP/ATP carrier adenine nucleotide translocator isoform 1 (ANT1) is protective in post MI inflammation.

Methods and Results:
MI was induced by permanent occlusion of left anterior descending artery in C57BL/6 mice. In the inflamed heart following MI, ANT1 protein levels were significantly decreased in the left ventricle (0.48±8.94%), indicating ANT1 down-regulation occurs in myocardial inflammation following MI. To delineate the mechanisms involved, we performed siRNA knockdown of ANT1 in myocardium-derived H9c2 cells and cardiomyocytes, and examined tumor necrosis factor alpha (TNFα)-induced pro-inflammatory response. Knocking down ANT1 significantly increased the expression of TNFα (~10-fold) and interleukin-6 (IL-6) (~3.6-fold) concomitant with increased reporter gene activity of nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) (~61±1.22%) in response to TNFα. These effects were not due to mitochondria loss because no changes were detected for voltage-dependent anion channel, or cyclophilin D when ANT1 is knocked down. Confocal microscopy analysis indicated that ANT1 knockdown increased TNFα-induced donut/blob-shaped mitochondria (~4.9-fold). Interestingly, exogenous TNFα and lipopolysaccharide (LPS) in turn significantly decreased ANT1 protein levels (~37±13%; ~37±6%, respectively) suggesting a feed forward regulation of pro-inflammatory cytokine expression activated by ANT1 down-regulation.

Conclusion:
These data suggest that cardiac inflammation is dependent on, in part, the function of ANT1. Preventing ANT1 down-regulation can be a novel molecular target to attenuate post MI inflammation and heart failure.
Abstract 60: The Role of Mononuclear Phagocytes in Pressure Overload Heart Failure
Authors: Patel Bindiya , Ismahil Mohamed , Goel Mehak , Hamid Tariq , Bansal Shyam , Prabhu Sumanth D
Published: July 2021

We previously reported that chronic ischemic HF induced by coronary ligation results in an exacerbated pro-inflammatory cell profile in the systemic circulation, spleen, and failing heart. In addition, this pro-inflammatory cell profile was strongly influenced by the cardiosplenic axis; however, the role of this axis in other etiologies of HF is unknown. Immune cells infiltrate the heart early (1-4 weeks) after pressure-overload injury, but it is unknown whether these cells persist and are of pathological import during chronic pressure-overload HF. We hypothesized that phenotypic changes in mononuclear phagocytes are necessary for the transition from compensatory hypertrophy to chronic HF during sustained pressure-overload, and that inhibition of myocardial immune cell infiltration would ameliorate this progression. Pressure-overload was induced by transverse aortic constriction (TAC) in wild-type (WT) C57BL/6 mice, and in macrophage Fas-induced apoptosis (MAFIA) Tg mice, which allows ablation of c-fms expressing cells upon administration of the AP20187 dimerizer. Compared to sham mice, TAC mice developed progressive cardiac dysfunction beginning at 2 w with significantly (p<0.05) reduced LVEF (59 ± 10 vs 67 ± 3 %), increased left atrial size (2.29 ± 0.1 vs 2.04 ± 0.1 mm), and increased E/E’ Doppler ratio (31.8 ± 6 vs 24.0 ± 3). Circulating CD11b+Lineage- monocytes were elevated in TAC mice at 2 w (1.7 ± 0.2 vs 1.0 ± 0.1 %, p<0.05); however, these levels normalized by 8 w. Moreover, at 8 w, no significant differences in the levels of splenic and cardiac mononuclear phagocytes were seen between TAC and sham mice. Systemic ablation of mononuclear phagocytes beginning 2 w after TAC in MAFIA AP20187-treated mice did not rescue cardiac function or delay HF progression compared to TAC MAFIA vehicle-treated mice over the course of 16 w (LVEF 43 ± 18 vs 45 ± 18 %). We conclude that in contrast to chronic ischemic HF, inflammatory cell-mediated cardiac injury does not have primacy in chronic non-ischemic HF induced by pressure-overload. These findings highlight the importance of the index injury in regard to immune cell activation in HF, and suggest that therapeutic immunomodulatory approaches may not be equivalent across the various etiologies of this disease.
Abstract 77: Distinct Profiles of Transient Receptor Potential Canonical (TRPC) Channel Expression in Biventricular Failure
Authors: Morine Kevin J , Paruchuri Vikram , Qiao Xiaoying , Pham Duc T , Huggins Gordon S , DeNofrio David , Kiernan Michael S , Yue Lixia , Karas Richard H , Kapur Navin K
Published: July 2021

Heart failure is a major cause of morbidity and mortality. The transient receptor potential canonical (TRPC) family of channels mediate pathologic cardiac remodeling. In particular, TRPC6 participates in a self-propagating circuit that amplifies cardiac hypertrophy and fibrosis. The objective of this study was to explore biventricular expression of TRPCs in advanced heart failure.

Methods:
Viable left (LV) and right (RV) ventricular free wall tissue was obtained from human subjects with end-stage heart failure (n=12) referred for transplantation or biventricular assist devices. Control LV and RV tissue was obtained from the National Disease Research Interchange (n=3/group). To explore TRPC expression in a murine model, adult male C57BL/6 mice underwent thoracic aortic constriction (TAC) for 10 weeks (n=6/group). Biventricular tissue was analyzed by real-time polymerase chain reaction.

Results:
Compared to normal LV and RV, levels of TRPC 1, 3, 4 and 6 were increased in failing LV and RV samples, respectively. Levels of TRPC1 and TRPC6 were greater in failing RV than failing LV samples. TRPC 5 and 7 expression were not consistently detected in normal or failing tissue samples. Compared to sham LV, levels of TPRC 1, 4 and 6 increased in the LV after TAC. Compared to sham RV, levels of TRPC 3, 4, and 6 increased in the RV after TAC. Levels of TRPC3 were greater in the RV than LV after TAC.

Conclusions:
Our results identify distinct profiles of TRPC expression in the RV versus LV in both human tissue and in a murine model of advanced biventricular failure. Levels of select TRPCs are higher in the failing RV compared to LV, suggesting a potentially important role for TRPCs in RV remodeling.
Abstract 80: Cardiac Fibroblast GRK2 Deletion Enhances Contractility and Remodeling following Ischemia/Reperfusion Injury
Authors: Woodall Meryl C , Woodall Benjamin P , Gao Erhe , Shang Xiying , Yuan Ancai , Ibetti Jessica , Koch Walter J
Published: July 2021

Decades of research have identified G Protein Coupled Receptor Kinase 2 (GRK2) as an important molecule that is upregulated in the cardiomyocyte after myocardial injury and during heart failure development. Research from our lab has convincingly demonstrated that myocyte-specific loss of GRK2 both before and after myocardial ischemic injury improves cardiac function and remodeling. Recent studies have reported that GRK2 is also upregulated in the cardiac fibroblast in the failing heart, suggesting a potential role for this molecule in the most abundant cell type in the heart. However, the in vivo implications of GRK2 expression in the fibroblast following cardiac stress remain a mystery. Tamoxifen inducible, fibroblast-specific GRK2 knockout mice (Col1α2CreER/GRK2flox) were treated with tamoxifen along with their control murine counterparts (GRK2flox alone) for 10 days to induce deletion of GRK2 in fibroblasts. Two weeks later mice were subjected to ischemia/reperfusion (I/R) injury via coronary artery occlusion for 30 minutes followed by periods of reperfusion. Fibroblast GRK2 knockout mice presented with preserved cardiac function 24 hours post-I/R compared to control mice as demonstrated by increased ejection fraction (58.1±1.8% vs. 48.7±1.2%, respectively, N=11-14, p=0.0005). GRK2 knockout mice also presented with decreased fibrosis in the infarcted area 72 hours following I/R injury as shown by Masson’s Trichrome staining. In line with decreased fibrosis, these mice also expressed decreased amounts of TGFβ1 and Collagen I. Additionally, α-smooth muscle actin expression is significantly diminished, indicating reduced fibroblast to myofibroblast transformation. These data suggest that GRK2 plays a key role up-stream in fibroblast activation and function in the ischemic heart and indicate that, like in the cardiomyocyte, inhibition of GRK2 in the cardiac fibroblast is a potential therapeutic target to limit cardiac dysfunction and remodeling after ischemic injury.
Abstract 93: A Gain-of-Function Mutation in Cardiac Myosin Binding Protein-C Increases Viscoelastic Load and Slows Shortening Velocity in Myocytes from Transgenic Mice
Authors: Bezold Kristina L , Khosa Jaskiran K , Harris Samantha P
Published: July 2021

Cardiac myosin binding protein C (cMyBP-C) is a sarcomeric protein involved in the regulation of cardiac muscle contraction. Effects of cMyBP-C on contraction are thought to be mediated in part by limiting the interactions of actin and myosin to slow myocyte shortening velocity and power output. Although interactions with myosin S2 on the thick filament have been proposed as a way in which cMyBP-C could limit shortening velocity (e.g., by creating a drag force on myosin heads), interactions of cMyBP-C with actin could also account for slowed shortening velocity. For instance, cMyBP-C could create a drag that opposes filament sliding by transiently linking thick and thin filaments together. To explore this possibility we created transgenic mice that express a mutant cMyBP-C with a point mutation, L348P (human L352P), located in a conserved sequence within the regulatory M-domain that increases cMyBP-C binding to actin in vitro. We reasoned that if the mutation also enhanced binding to actin in sarcomeres then shortening velocity would be slowed in myocytes from L348P mice. Results show that transgenic mice expressing the L348P mutation are viable and that L348P cMyBP-C is expressed in sarcomeres. Permeabilized myocytes from transgenic mice showed altered force production including reduced maximal force and enhanced calcium sensitivity of tension. Shortening velocity and power output were significantly reduced whereas passive stiffness and myocyte visco-elasticity were significantly increased. Together these data are consistent with the idea that cMyBP-C creates an internal load in the sarcomere by binding to actin.
Abstract 95: Longitudinal In Vivo Quantification of Infarct Size and Cardiac Function in a Murine Model of Myocardial Infarction using Novel Compact High-Performance MRI
Authors: Coulthard Tonya , Wu Jun
Published: July 2021

Intro:
Delayed Enhancement Imaging (DEI) characterizes MI and predicts therapeutic efficacy following coronary revascularization, stem cell transplantation, or other procedures. Typically gadolinium-based (Gd) contrast agents are injected intravenously and accumulate in the lesion, differentiating between normal and diseased myocardium.

Traditionally, DEI has been explored using superconducting high-field MRI. Using a novel compact MRI at 1 Tesla, there is increased sensitivity to Gd-based contrast agents compared with higher-field MRI systems.

Hypothesis:
In this study, DEI on a compact MRI system was employed with spatial intensity analysis to measure infarct size. Tagged cine MRI assessed myocardial strain using the HARP method. Post-mortem histology of Masson Trichrome staining estimated infarct size. Correlation analysis determined relationships between infarct size measured via DEI and histology.

Methods:
C57BL/6 MI mice had ligation of the left anterior descending artery. Four sham control and five MI mice we imaged using compact MRI (ICON compact MRI, Billerica, MA) and monitored longitudinally over 21 days for infarct progression and cardiac function in vivo. DE imaging was performed 10-20 minutes post injection of 2 μL Gd contrast agent (ProHance, 0.5 mmol/ml). Images were acquired in short axis, 1 mm superior to the apex. Post-processing analysis (pcVirtue, Diagnosoft, Morrisville, NC) measured cardiac function and infarct size.

Results and Conclusions:
Analyses of DEI data indicate an average infarct size of 24.85 +/- 15.09 % in the left ventricle. One week after MI induction, a much lower EF was observed in MI mice with respect to control (35.3 +/- 7.567% vs. 67.3 +/- 1.6 %), with a slight recovery of cardiac function in MI mice by week 3 (EF = 45.5 +/- 3.1%). Strain analysis also indicated significantly lower average peak strain in MI vs control mice (6.9 +/- 4.3 vs. 21.5 +/- 0.4 %).

Preliminary results demonstrate successful monitoring of cardiac function while performing DEI to visualize and quantify MI at 1 Tesla and leverage the benefits of the increased sensitivity of Gd-based contrast imaging with novel compact MRI. Such imaging and analysis techniques could be used to test efficacy of multiple therapeutic interventions.
Abstract 117: Heparin Derived Oligosaccharide Inhibits Vascular Intimal Hyperplasia in Balloon Injured Carotid Artery and the Mechanism Involved
Authors: Shuying He , Jie Wu
Published: July 2021

To determine the effects of heparin-derived oligosaccharides (HDOs) on vascular intimal hyperplasia (IH) in balloon-injured carotid artery and the mechanism involved. The animal model was established by rubbing the endothelia within the common carotid artery (CCA) of male rabbits along with a high-cholesterol diet. The arterial IH was testified by histopathological changes of the CCA. Serum lipids were detected using automated biochemical analysis; Expression of mRNAs corresponding to vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), vascular cell adhesion molecule-1 (VCAM-1), monocyte chemoattractant protein-1 (MCP-1), scavenger receptor class B type I (SR-BI) and ATP-binding cassette transporter A1 (ABCA-1) were analyzed using reverse transcription polymerase chain reaction assays. Expressions of VEGF, VCAM-1, MCP-1, SR-BI and ABCA-1 proteins were detected by western blotting. Enzyme-linked immunosorbent assays were used to quantify expression levels of VEGF and bFGF. The results implied that administration of HDO significantly inhibited common carotid artery histopathology and restenosis that was induced by balloon injury. Treatment with HDO also significantly decreased mRNA and protein expression levels of VEGF, bFGF, VCAM-1, MCP-1, and SR-BI in the arterial wall, however ABCA-1 expression levels were elevated. HDO treatment led to a reduction in various serum lipids (total cholesterol, triglycerides, high-density and low-density lipoproteins). We concluded that, in a rabbit model, HDO can ameliorate IH and the mechanisms might involved VEGF, bFGF, VCAM-1, MCP-1, SR-BI and ABCA-1.
Abstract 118: PP2A/HSP70 Dynamically Regulates HDAC2 Phosphorylation and its Activity in Cardiac Hypertrophy
Authors: Eom Gwang Hyeon , Yoon Somy , Min Hyun-Ki , Nam Yoon Seok , Kwon Duk-Hwa , Kook Hyun
Published: July 2021

Rationale:
Cardiac hypertrophy is an adaptation for increased hemodynamic demands by underlying diseases and histone deacetylase (HDAC) 2 phosphorylation and following its activation are closely associated with those of process. Recently, we have demonstrated that the acetylation of HDAC2 K75 could induce S394 phosphorylation; however, specific mechanism for inter-modifications regulation in the single protein largely remains unclear.

Objective:
We aimed to delineate the regulation mechanism how K75 acetylation modulates S394 phosphorylation and which phosphatase regulates HDAC2 phosphorylation in the cardiac hypertrophy.

Methods and Results:
We found that the catalytic subunit of protein phosphatase (PP) 2A bound to HDAC2 in the H9c2 cell. PP2A kept HDAC2 unphosphorylated in the absence of hypertrophic stresses. Hypertrophic stresses-induced activation of pCAF, however, induced HDAC2 K75 acetylation, which then allowed PP2A to dissociate from HDAC2. This dissociation leads CK2α1 to bind to and phosphorylate HDAC2. Hypertrophic stresses induced HSP70 which then preferentially bound to phosphorylated HDAC2 rather than to unphosphorylated one. Forced expression of PP2CA not only reduced enzyme activity of HDAC2 but inhibited hypertrophic response in the cardiomyocytes. On the other hand, HSP70 bound to phosphorylated HDAC2 in order to mask the phosphor-HDAC2 from PP2CA. HDAC2 phosphorylation and following activation of intrinsic activity were regulated by binding of PP2CA to HDAC2. PP2A functioned as a negative regulator for cardiac hypertrophy by targeting of HDAC2 S394 phosphorylation.

Conclusion:
Taken together, HDAC2 forms a complex with PP2A in the absence of hypertrophic stresses and remains inactivated. HDAC2 acetylation results in both detachment of PP2A and binding of CK2α1 for phosphorylation, which is maintained by the association with HSP70 during development of cardiac hypertrophy.
Abstract 122: Hyperinsulinmia Promotes Cardiac Dysfunction via Upregulation of Phosphodiesterase in Heart
Authors: Xiang Yang K
Published: July 2021

Accumulating evidence suggests that hyperinsulinemia contributes to heart dysfunction. Here we show that insulin signaling is responsible for high fat diet (HFD) feeding-induced expression of phosphodiesterase 4D (PDE4D) in the myocardium of mice. The increased expression of PDE4D, in concert with reduced phosphorylation of phospholamban (PLB), promotes systolic and diastolic heart dysfunction. We revealed that insulin-mediated induction of PDE4D was dependent on β2AR-mediaed β-arrestin2-ERK pathway, which is transactivated in a GRK2-dependent fashion. Deletion of β2AR gene significantly attenuated insulin-induced phosphorylation of extracellular signal-regulated kinase (ERK) and Akt, as well as the upregulation of PDE4D expression, which prevented the heart dysfunction. β-arrestin2 KO mice did not display increased PDE4D expression and did not develop systolic or diastolic dysfunction following HFD. In brief, these data indicate that chronic hyperinsulinimia leads to heart dysfunction by increasing PDE4D expression via β2AR-GRK2-β-arrestin2 -ERK pathway, which suggests that β2AR signaling could be an attractive therapeutic target for preserving or improving cardiac function in subjects with insulin resistance.
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.