bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 464: Dynamic Regulation of the Epidermal Growth Factor Receptor Protein Interactome via β1-adrenergic Receptor-mediated Transactivation in Cardiomyocytes
Authors: Einspahr Jeanette
Published: October 2020

Heart Failure (HF) is a chronic, progressive condition wherein the heart cannot perfuse adequate amounts of blood and oxygen to meet the demands of metabolizing tissues. Gold standard HF therapeutics currently consist of a small repertoire of neurohormone modulators that still result in ~50% mortality within 5 years. Our ongoing goal is to develop new signaling modalities as refined HF therapeutics. We have shown that β1-adrenergic receptor (β1AR) stimulation rapidly induces epidermal growth factor receptor (EGFR)-dependent protein signaling responses in various regions of cardiomyocytes (CM). We hypothesize that differences in the subcellular localization and protein interactomes of EGFR following differential ligand stimulation modulate CM functions in distinct manners. To test this, we infected neonatal rat ventricular myocytes (NRVM) with adenoviruses encoding HA-β1AR and Flag-EGFR, stimulated them with vehicle, isoproterenol or EGF for 5 min and performed mass spectroscopy analysis of the Flag-EGFR immunoprecipitates. While hundreds of protein interactions were identified, one of the highly enriched subcellular groups belonged to mitochondrial proteins, for which there is no information regarding the role of EGFR in their regulation in CM. Via fractionation and digestion analyses, we have confirmed EGFR localization to the outer mitochondrial membrane in CM and have begun to assess the impact of EGFR on mitochondrial function. Transmission electron microcopy analysis of mitochondrial morphology show that CM-specific EGFR knockdown (CM-EGFR-KD) increases mitochondrial circularity and mitochondria/area without changes in other parameters including perimeter or cristae density, suggesting altered bioenergetic potential. Indeed, extracellular flux (Seahorse) analysis of CM-EGFR-KD versus control CM revealed that CM-EGFR-KD increased maximal and reserve capacities and a trend toward increased ATP production. Elucidating the mechanism(s) of EGFR localization to and association with proteins at CM mitochondria, as well as its impact on mitochondrial function normally or in response to catecholamine stimulation will provide insight into the potential utility of targeting mitochondrial EGFR to improve HF outcomes.
Abstract 472: Liver X Receptor Ligands Suppress Intestinal Soat2 and Reduce Cholesterol in Mice Fed a High Cholesterol Diet
Authors: Griffett Kristine , Diaz Gonzalo , Sanders Ryan , Hayes Matthew , Burris Thomas P
Published: October 2020

The nuclear receptors, liver X receptor-alpha and -beta (LXRa and LXRb), were originally identified as orphan members of the nuclear receptor (NR) superfamily that function as heterodimers with the retinoid X receptor (RXR). Both LXRa and LXRb play important roles in cholesterol homeostasis and lipid metabolism and have been implicated in the pathology of several diseases including atherosclerosis, cancer, and obesity. Detailed examination of mice deficient in LXRa have revealed significant information regarding its role in regulating lipid metabolism while pharmacological roles of LXR in metabolism and inflammation have been identified using synthetic agonists. We have identified novel synthetic LXR Inverse Agonists that display the ability to suppress lipogenesis and significantly improve the phenotype of fatty liver diseases in several mouse models. During our previous investigation of LXR inverse agonists and fatty liver, we observed a substantial decrease in LDL and total cholesterol, as well as a significant decrease in
soat2
gene expression. Recent basic and clinical studies indicate that
soat2
may be a potential therapeutic target for cholesterol regulation and atherosclerosis treatment. Based on our observations, we investigated the effects of tissue-selective LXR inverse agonists on cholesterol regulation with greater intensity. We hypothesized that
soat2
may be a novel target of LXR and that selectively suppressing LXR in the liver and/or intestine may lead to lowered cholesterol levels in hyperlipidemic models (n = 12). While our research is currently ongoing, we have validated
soat2
as a potential LXR target gene by ChIP in hepatocytes, RNA-Seq experiments, fecal cholesterol excretion experiments, as well as expression assays in LXRa/b double knockout mouse tissues (n = 3). Additional studies in LDLr KO mice indicate that selectively targeting LXR in the gut with inverse agonists significantly decrease total and LDL cholesterol (n=12). We believe that this is an innovative method of targeting hypercholesterolemia and may lead to a new class of atherosclerosis therapeutics.
Abstract 474: ERK4-deficiency Potentiates the TAC-induced Increase in Collagen1-α
1
Messenger RNA in Mice
Authors: Trepanier Joelle , Dingar Dharmendra D , Gillis Marc-Antoine , Sahadevan Pramod , Shi Yan Fen , Sirois Martin G , Meloche Sylvain , Tardif Jean-claude , Allen Bruce G
Published: October 2020

Cardiac hypertrophy, a common consequence of cardiopathologies such as hypertension and myocardial infarcts, involves formation of excessive interstitial fibrosis, which may impair cardiac function. Fibroblasts are the primary source of extracellular matrix protein. Extracellular-regulated kinase 4 (ERK4) is an atypical mitogen-activated protein kinase (MAPK). The regulation and role of ERK4 in the heart are currently unidentified and its only known target is MAP kinase-activated protein kinase 5 (MK5), a kinase involved in regulating fibroblast function. Following constriction of the transverse aorta (TAC), MK5 haplodeficient mice showed an attenuation of the TAC-induced increase in collagen 1-α
1
mRNA at 2-wk post-TAC and reduced hypertrophy 8-wk post-TAC. Further studies revealed MK5 immunoreactivity in cardiac fibroblasts but not myocytes. MK5 immunoprecipitates from whole heart contain ERK3 immunoreactivity, but not that of ERK4 or p38 MAPK. This study was to examine the role of ERK4 in myocardial structure, function, and remodeling 3-wk post-TAC.

At 12 wk of age, echocardiographic imaging revealed systolic and diastolic function in male ERK4
-/-
mice were similar to wild-type littermates (ERK4
+/+
). Three weeks post-TAC, hypertrophy was similar in ERK4
+/+
and ERK4
-/-
mice. Transcripts for BNP and βMHC increased to similar extent in TAC- ERK4
+/+
and TAC- ERK4
-/-
mice. Two-way ANOVA indicated that ERK4 deficiency altered the effect of TAC on TGFβ
1
and collagen 1-α
1
transcript levels with each being higher in TAC-ERK4
-/-
mice. Furthermore, MK5 immunoprecipitates from cardiac fibroblast lysates did not contain ERK4 immunoreactivity. Additional experiments revealed the presence of ERK4 immunoreactivity in myocytes but not fibroblasts.

These results suggest 1) ERK4 may be involved in myocyte - fibroblast communication during myocardial remodeling and 2) in cardiac myocytes, ERK4 is part of a novel signaling cascade that does not involve MK5.
Abstract 475: Beta-adrenoceptor Stimulation Uniquely Regulates Exosome Micro-rna Content Secreted From Cardiomyocytes
in vitro
and Those Found
in vivo
Circulating in Blood
Authors: Kwon Jin Sook , Gao Erhe , Roy Rajika , Ibetti jessica , Chuprun J Kurt , Koch Walter J
Published: October 2020

Background and Purpose:
The influence of β-adrenoceptor (βAR) signaling on the regulation of exosomes secreted from cardiomyocytes is unknown and since catecholamines are increased in heart failure (HF), there is interest in uncovering whether βARs can induce specific changes in the content of circulating blood exosomes in HF. In this study, we have evaluated whether βAR stimulation by isoproterenol (ISO) on neonatal rat ventricle myocytes (NRVMs) and in vivo in mice can alter the number, size and microRNA (miR) content of secreted exosomes.

Methods and Results:
ISO treatment of NRVMs did not change exosome number and size of compared than vehicle (PBS). After purifying total RNA from treated myocytes and secreted exosomes, we evaluated the expression level of 37 candidate miR’s, which were selected from previous microarray data. We found that ISO treatment decreased 14 miR’s (miR-222, -106a, -292a, -181b, -210, -489, -214, -1947, -195, -17, -7b, -93, -532 and -19a) in exosomes and in the myocytes themselves, mir-292a and -1947 were up regulated and mir-7b, down regulated. Further, ISO was then used to treat C57 mice via osmotic pump chronically. The number and size of exosomes purified from circulating blood was not changed after 2 and 8 weeks. We evaluated expression of the 14 miRs down-regulated in myocytes as well miR-1 and -21 (important cardiac miRs) both in the blood and hearts of ISO-treated mice. MiR-1 did not change in both blood exosomes and heart tissue and miR-21 was up-regulated in heart tissue but not in blood both at 2 and 8 weeks after ISO treatment. In addition, miRNA-489 and -7b was down-regulated in hearts with miR-214 and -292a up regulated. In blood exosomes, we found only down-regulation of miR-489 and -7b but not miR-214 and 292a.

Conclusions:
We found that the βAR agonist ISO altered exosomal miR contents but not exosome size and number from myocytes. Importantly, this was found in myocytes in culture and in vivo blood and myocardium that were treated with ISO but several differences were found and changes in blood and myocytes were not homogeneous. However, two miRs, mir-7b and -miR-489, both changes similarly from their origin (NRVMs or mouse hearts) and also in circulating blood exosomes. Therefore, these miRs may represent biomarkers for sympathetic nervous system abnormalities in HF and their therapeutic potential should be evaluated.
Abstract 477: Modeling the Effect of
TBX5
Downregulation on Human Atrial Conduction Using Induced Pluripotent Stem Cell-derived Cardiomyocytes
Authors: Biendarra-tiegs Sherri M , Yechikov Sergey , Houshmand Laura , Gonzalez R. E , Lu Zhi Hong , Curiel David T , Rentschler Stacey L , George Steven C
Published: October 2020

Atrial fibrillation (AF) poses a notable healthcare burden due to a high incidence in the increasing population over age 65 and limitations of current treatment approaches. One challenge to effectively treat AF is patient-to-patient heterogeneity in the underlying mechanisms of disease. Therefore, a better understanding of AF pathogenesis and more personalized approaches to therapy could reduce risk of side effects and improve therapeutic efficacy. Genome wide association studies (GWAS) have revealed several candidate genes for AF including
TBX5
, which encodes for a transcription factor involved in heart development. While work in animal models suggests that loss of
TBX5
promotes atrial arrythmias, experimental evidence in human cells is lacking. We created an
in vitro
model of human atrial conduction using day 60+ induced pluripotent stem cell-derived atrial-like cardiomyocytes (iPSC-aCMs) differentiated from three established healthy iPSC lines. Over 90% atrial-like purity (out of 350+ alpha-actinin positive cardiomyocytes) could be achieved based on MLC2v-/MLC2a+ immunofluorescent staining.
TBX5
knockdown via esiRNA resulted in downregulation of genes related to conduction velocity (
GJA5
and
SCN5A
), consistent with an enhanced risk of AF. Single cell optical electrophysiology demonstrated slightly reduced action potential amplitude and upstroke velocity for
TBX5
knockdown cells versus GFP esiRNA controls, suggesting a functional effect of
SCN5A
downregulation. Additionally, microelectrode array studies have revealed a trend towards slowed conduction velocity with
TBX5
knockdown compared to GFP esiRNA controls (13.1±3.0 cm/s vs 17.0±3.8 cm/s respectively). By further investigating the functional effects of modulating transcription factors such as
TBX5
in iPSC-aCMs, our results provide enhanced insight into the regulation of atrial conduction and identify potential AF-related pathways for therapeutic targeting.
Abstract 480: Non-muscle Myosin II Regulates Aortic Stiffness via Tension-dependent Phosphorylation of Specific Focal Adhesion Proteins
Authors: Singh Kuldeep , Kim Anne B , Morgan Kathleen G
Published: October 2020

Non-muscle myosin II plays a role in many fundamental cellular processes including cell adhesion, migration, and cytokinesis. However, its role in vascular function is not well understood. Here, we investigated the function of non-muscle myosin II in the biomechanical properties of mouse proximal aorta. We found that blebbistatin, a specific inhibitor of non-muscle myosin II decreases agonist-induced aortic stress and stiffness in a dose-dependent manner. We also specifically demonstrate, in freshly isolated contractile aortic smooth muscle cells, using deconvolution microscopy that the NM myosin IIA isoform co-localizes with contractile filaments in the core of the cell as well as in the non-muscle cell cortex. However, the NM myosin IIB isoform is only colocalized with contractile filaments, and is excluded from the cell cortex. Furthermore, both the siRNA knockdown of NMIIA and NMIIB isoforms in a differentiated smooth muscle cell line A7r5 and blebbistatin-mediated inhibition of NM myosin II suppresses agonist-activated increases in phosphorylation of FAK Y925 and paxillin Y118. Thus, in the present study, we show, for the first time, that NM myosin II regulates aortic stiffness and that this regulation is mediated at least in part through the tension-dependent phosphorylation of focal adhesion proteins FAK and paxillin.
Abstract 482: Beta-catenin Activation in Cardiac Fibroblasts Modulates the Immune Micro-environment to Promote Fibrosis and Heart Failure Following Chronic Injury
Authors: Melzer Meiling , Hassan Dina , Beier David , Young Pampee P , Saraswati Sarika
Published: October 2020

Almost 6.5 million people in United States suffer from heart failure (HF). Diastolic HF following non-ischemic cardiac insult is a progressive condition with limited effective therapies underscoring the urgency to invest in identifying novel therapeutic targets for treatment. Reactive fibrosis in response to pathological stress is one of the major causes of diastolic HF. Emerging data suggest an association of systemic inflammation with reactive fibrosis and HF. Canonical Wnt/beta-catenin signaling has been linked to HF and fibrosis with limited understanding of the precise cellular and molecular mechanism. We utilized thoracic aortic constriction (TAC), a well-defined model of HF, to study Wnt signaling mediated reactive fibrosis. TAC was induced in a transgenic mouse model with stabilized beta-catenin (Wnt signaling) in fibroblasts (Bcat/Postn). Wnt activation following TAC resulted in increased maladaptive reactive fibrosis, HF marker ANP, and cardiac hypertrophy with preserved Ejection Fraction (pEF) suggesting Wnt-mediated progression of diastolic heart failure with pEF. TAC also resulted in increased macrophage activation and recruitment of CD8+ cytotoxic T-cells.
In vitro
co-culture of Wnt3a-overexpressing fibroblasts with activated myeloid cells promoted fibroblast proliferation and collagen synthesis. Therefore, we hypothesize that Wnt signaling activation promotes interstitial fibrosis via recruitment of specific inflammatory cells. Genomic analysis further supports this by demonstrating distinct chemokine gene expression patterns in fibroblasts resulting from Wnt activation in these injury models. Our future goal is to elucidate the role of Wnt signaling in modulating the fibroblast-immune cell crosstalk in modulating interstitial fibrosis induced diastolic HFpEF. Currently, there is no approved therapy to specifically target reactive fibrosis to avert diastolic dysfunction. Our study is aiming to identify targetable cellular and molecular players that improve, prevent or avert reactive fibrosis mediated HFpEF in order to reduce the incidence and severity of pathology resulting from HF.
Abstract 484: Alcohol Abuse Increases the Risk of In-hospital Mortality in Arrhythmia: A Nationwide Analysis of 114,958 Inpatients
Authors: PATEL RIKINKUMAR S , Ravat Virendrasinh , Ajibawo Temitope
Published: October 2020

Objectives:
In our study, we aim 1. to evaluate the differences in demographics in arrhythmia inpatients by comorbid alcohol abuse, and 2. to assess the risk of in-hospital mortality due to alcohol abuse.

Methods:
We conducted a cross-sectional analysis using the nationwide inpatient sample (NIS, 2010-2014). We included 114,958 patients (age, 15-54y) hospitalized for arrhythmia and further grouped by comorbid alcohol abuse. Logistic regression was done to measure the odds ratio (OR) of association of alcohol abuse with mortality.

Results:
The prevalence of alcohol abuse in arrhythmia inpatients was 9.75%., and these patients were old-age (45-54y, 68%), male (85.9%) and White (69%). The mortality risk statistically increases with age with adults (45-5y) having two times higher risk (95% CI 1.5-3.1). Males had a lower risk compared to females (OR 0.8, 95% CI 0.7-0.9). Atherosclerosis (OR 4.5, 95% CI 3.4-5.9) and diabetes (OR 1.4, 95% CI 1.2-1.7) significantly increased mortality risk in arrhythmia inpatients. Mortality was seen in a higher proportion of alcohol abusers (1.9%) cohort compared to non-users (1.4%). And, alcohol abuse increased the risk of mortality during hospitalization (OR 1.7, 95% CI 1.4-2.1) after controlling for demographic confounders and cardiovascular comorbidities.

Conclusions:
The risk of mortality is higher in older-age adults and females with arrhythmia. Alcohol abuse independently increases the risk of mortality by 72% in arrhythmia inpatients. Social alcohol drinking and its impact on arrhythmias in non-alcoholics needs to be studied. Strategies to reduce alcohol consumption and abstinence should be focussed to improve the quality of life of patients with cardiovascular risk factors.
Abstract 486: Chronic Periodontitis Induces Adverse Post-myocardial Wound Healing Through Activation of CD8+ T-cells
Authors: Zaidi Yusra , Troncoso Miguel , Ilatovskaya Daria , Deleon-pennell Kristine Y
Published: October 2020

Increased risk of adverse cardiac remodeling post-myocardial infarction (MI) has been observed in patients with periodontal disease. Previously, we demonstrated that chronic inflammation induced by periodontal pathogen
Porphyromonas gingivalis
lipopolysaccharide (LPS) resets cardiac homeostasis, causing acceleration and exacerbation of the macrophage response post-MI. We hypothesize that chronic LPS activates a memory T-cell response resulting in adverse cardiac remodeling post-MI. Analysis of the mouse heart attack research tool (mHART) 1.0 identified 135 mice (5.4 ± 0.1 months of age) associated with the LPS study that had both echo and plasma data collected. Of these 26 mice also had tissue blocks in the mHART tissue bank. Mice were grouped as follows: 1) Saline day 0 unoperated mice (D0), 2) 28 day LPS day 0 unoperated mice (LPS), 3) Saline day 1 MI (MI), and 4) 28 day LPS day 1 MI (LPS+MI). Immunofluorescence of the left ventricle (LV) demonstrated that chronic LPS increased the number of memory CD8+ T-cells (CD3+CD8+CD27+) in the LV and remained elevated in the LPS+MI group compared to D0 and MI controls. Similar to chronic LPS, ligature-induced periodontitis (21 days) also showed upregulation of CD8+ T-cells in the LV along with changes in plasma proteins associated with interleukin, cytokine, chemokine receptor binding, peptide ligand-binding, inflammasome pathway, class A/1 rhodopsin-like receptors, G-protein coupled receptor ligand binding, and RUNX1 and FOXP3 control of Treg development and signaling. To dissect T-cell mediated signaling pathways, we constantly infused an MHC-I blocking antibody (MHCi; 0.2 μg/day; n=3) by osmotic mini-pumps implanted subcutaneously 7 days before (21 days after LPS infusion) and after MI surgery. Interestingly, MHCi attenuated the effector CD8+ T-cell response (CD3+CD8+CD44+) without affecting the memory response. MHCi also attenuated macrophage numbers within the infarct, thereby improving cardiac function at post-MI day 1. Our data showed the recruitment of effector but not memory CD8+ T-cells is regulating macrophage-mediated adverse post-MI remodeling in the setting of chronic periodontitis.
Abstract 489: Identification And
In-silico
Analysis Of Pathogenic Non-synonymous Snps Of Human Sos1 Protein In Noonan Syndrome
Authors: Sigamani Vinoth , RAJASINGH SHEEJA , Gurusamy Narasimman , Kirankumar Shivaani , Vasanthan Jayavardini , Johnson Rajasingh
Published: October 2020

Introduction:
Noonan syndrome is a genetic disorder (autosomal dominant) characterized by short stature, congenital heart disease, bleeding problems, developmental delays, and skeletal malformation. It is mainly caused by a single nucleotide alteration in four genes
PTPN11, SOS1, RAF1, and KRAS
. In this study, we computationally analyzed the
SOS1
gene to identify the pathogenic non-synonymous single nucleotide polymorphisms (nsSNPs), which is known to cause Noonan syndrome.

Hypothesis:
We hypothesize that
in-silico
analysis of human SOS1 mutations in Noonan syndrome would be a promising predictor to study the post-translational modifications.

Methods and Results:
The variant information of
SOS1
was collected from the dbSNP database and the literature review on Noonan syndrome. They were further analyzed by in-silico tools such as I-Mutant, iPTREE-STAB, and MutPred for their structural and functional properties. We found that 11 nsSNPs are more pathogenic for Noonan syndrome. The 3D comparative protein of 11 nsSNPs with its wild-type SOS1 was modeled by using I-Tasser and validated via ERRAT and RAMPAGE. The protein-protein interactions of SOS1, GATA4, TNNT2, and ACTN2 were analyzed using STRING, which showed that HRAS was intermediate between SOS1 and ACTN2
(Fig. 1)
.

Conclusion:
This is the first
in-silico
study of the
SOS1
variant with Noonan syndrome. We proposed that this 11 nsSNPs are the most pathogenic variant of
SOS1
, which helps to screen the Noonan patient. Furthermore, our results are promising to study the gain/loss of post-translational modification (PTM) by mutation in cardiac genes and helps to explore the novel molecular pathways.$graphic_{DB5B0E7D-4DA6-4569-A16F-E05B2C9C4D2F}$$
Abstract 492: Dual Stem Cell Therapy Improves the Cardiac Function After Experimental Myocardial Infarction
Authors: Popescu Sinziana , Lupan Ana-Mihaela , Bogdan Mihai Preda , Simionescu Maya , Burlacu Alexandrina
Published: October 2020

As the mortality associated with cardiovascular diseases has accelerated in the past 10 years, advances in treatment options can have significant impact on the global population health. Mesenchymal Stromal Cells (MSC) have shown limited efficacy in clinical trials as sole contributors to tissue regeneration. Thus, we questioned whether the presence of Endothelial Colony Forming Cells (ECFC) could improve MSC-based cellular therapy of the infarcted myocardium. Acute myocardial infarction was induced in immunodeficient NSG mice by left coronary artery ligation and then MSCs or MSCs+ECFCs were immediately injected in the ventricular wall. Both healthy and sham-treated infarcted mice served as controls. At 7 days post-transplantation, echocardiography, qPCR and Western Blot (WB) were performed to assess cardiac function and protein expression. MSC - ECFC reciprocal modulation was studied in vitro by 24-hour co-culture in dual-chamber system or in direct contact, followed by qPCR and WB. The secretome collected from cultures was characterized by Matrigel angiogenesis assay, Proteome Profiler Arrays and ELISA. The results revealed that in dual-cell transplant compared to single transplant group the cardiac function (ejection fraction and stroke volume) was significantly improved. The protein expression of junctional molecules such as Connexin 43 and Integrin α-5 was increased by more than twofold in the MSC+ECFC
vs.
MSC-only group. Moreover, both MSC and ECFC secreted high levels of pro-angiogenic molecules, with only partially overlapping profiles, capable of inducing tube-like vascular structures on Matrigel. These observations suggest a putative complementary contribution of MSC and ECFC to the cardiac repair process. Significant increase in the Integrin α-5 expression was achieved in both culture settings, indicating a mechanism independent of cell to cell contact. However, a synergistic paracrine effect of the MSC-ECFC pair only occured after close cell interaction, especially for VEGF, SDF-1 and YKL-40, thus suggesting that both cell types are needed for sustained effects. In conclusion, we provide evidence that the complementary, dual stem cell-based therapy could positively modulate the function of infarcted myocardium.
Abstract 494: Mitral to Meninges: Aspergillus Endocarditis With Septic Emboli
Authors: Smith Christopher T , Smith Dantwan , Arshad Waqaar
Published: October 2020

Introduction:
Fungal endocarditis comprises less than 2% of infective endocarditis, with Aspergillus causing less than 28% of fungal endocarditis. Fungal endocarditis should be suspected in immunocompromised patients with persistent fevers, negative blood cultures, and vegetation on echocardiography. Invasive Aspergillus can affect any organ, but typically begins in the respiratory tract. Mortality rates climb to 90% with signs of hematogenous spread, such as cerebral abscesses.

Case Presentation:
Patient is a 53-year-old female with a past medical history of Sweet syndrome and chronic pancreatitis. Patient was admitted for persistent fevers and confusion. Patient was tachycardic but normotensive with a temperature of 102.5 F. Labs included significantly elevated serum LDH and Beta-D-Glucan. Blood cultures remained negative. Lumbar puncture cultures were negative; CSF cytology revealed pleocytosis with positive Aspergillus galactomannan serum antigen. Head MRI revealed multiple peripherally enhancing supratentorial lesions and intracranial abscesses (largest 8.4 mm) with ventriculitis of lateral ventricles, right greater than left. Transesophageal Echocardiogram (TEE) revealed mitral valve vegetation at A2 segment, no surrounding perivalvular abscess, minimal mitral regurgitation (MR).

Management:
Antibiotics were discontinued and patient was counseled on avoiding glucocorticoids. Patient was transferred to large tertiary center for Neurosurgery evaluation but was not candidate for biopsy/aspiration of the ring-enhancing lesions per Neurosurgery. Cardiothoracic Surgery was also consulted and patient was not a candidate for mitral valve replacement due to small size of vegetation without abscess and only mild MR. Voriconazole was continued and patient ultimately demonstrated a slow improvement in her strength and mental status over the next 6 months.

Discussion:
Mitral endocarditis from Aspergillus is rare but has a very high mortality rate. This case illustrates the importance of early recognition of systemic fungal infections in the setting of immunosuppression. Glucocorticoids and broad-spectrum antibiotics placed this patient at elevated risk for invasive Aspergillosis, which led to mitral endocarditis and subsequent cerebral abscesses from septic emboli.
Abstract 500: Impact of Oxidative Stress and Fancj on Heart Health
Authors: Lowran Kaitlin A , McCarthy Mikayla , Campbell Laura , Wu Colin
Published: October 2020

G-quadruplexes (or G4s) are structures formed by guanine-rich nucleic acid sequences. G4s must be promptly unfolded in cells; otherwise, they can interfere with DNA replication, RNA transcription, and other essential processes. Guanines bases are susceptible to oxidative stress forming 8-oxoguanines (8oxoG). Although 8oxoG-modified DNA sequences can still fold into stable G4s, it is not known how 8oxoG4s are repaired in human cells. In our previous study, we have shown that the FANCJ DNA helicase targets G4s using an AKKQ amino acid motif. Here, we have examined the interactions of FANCJ with various 8oxoG4s using biolayer interferometry and fluorescence spectroscopy. We show that a FANCJ AKKQ peptide alone can recognize G4s with an affinity of 3.7uM. Moreover, this motif binds to 8oxoG4s with greater affinities of 1.3 to 2.3uM. A detailed description of the mechanisms by which 8oxoG4s are repaired is essential for understanding how human hearts respond to oxidative stress. To test the importance of FANCJ AKKQ-G4 interactions in cells, we measured the total extent of oxidative DNA damage in human cardiac cells by single-cell electrophoresis. Cells that overexpress FANCJ can readily overcome the chemical stress induced by hydrogen peroxide treatment and the G4-stabilizing compound telomestatin. On the contrary, cells that produce a FANCJ AAAQ mutant, which cannot interact with G4s, resulted in an accumulation of 8oxoG4s. Based on this evidence, FANCJ plays an important role to alleviate the damage caused by oxidative stress. In future experiments, we plan to further examine the cardiovascular risks of DNA damage caused by FANCJ malfunctions.
Abstract 505: Diabetes Mellitus-Induced Metabolic Remodeling is Alleviated by Transgenic Overexpression of Mir-133a in the Heart
Authors: Kambis Tyler , Mishra Paras K
Published: October 2020

Diabetic mellitus (DM) cardiomyopathy is a DM-induced metabolic disorder where energy dependence on fatty acid (FA) metabolism causes FA influx overload. While we reported that miR-133a overexpression prevented deleterious lipid accumulation in the diabetic Akita heart, it is unclear whether miR-133a regulates diabetes-induced metabolic remodeling in the DM heart. Thus, we performed deep sequencing on the heart from DM Akita (Ak), cardiac-specific miR-133aTg (Tg), Ak/Tg mice, and sibling wild-type (WT) mice. Ingenuity pathway analysis showed that FAO was the highest activated pathway in the DM heart (p-value=4.59E-11). Therefore, we hypothesized that miR-133a overexpression in the DM heart improves cardiac metabolism by increasing FA clearance via enhancing FA oxidation (FAO). Notably, mitochondrial FA transport protein carnitine palmitoyltransferase I (CPT1) was upregulated (WT: 0.02±0.01, Ak: 0.06±0.02, Ak/Tg: 0.17±0.02, Tg: 0.06±0.01) while changes in the intracellular FA transport protein CD36 were not significant. Interestingly, the rate-limiting enzyme of ketogenesis, the FAO spillover pathway, 3-Hydroxy-3-Methylglutaryl-CoA Synthase 2 (HMGCS2) was downregulated (WT: 0.13±0.02, Ak: 0.74±0.13, Ak/Tg: 0.39±0.07, Tg: 0.05±0.01) in Ak/Tg mice. These results support that increased miR-133a in the diabetic heart contributes to improved FAO and FA metabolism in addition to downregulating FA deposition and ketogenesis in the diabetic heart.
Abstract 506: Enhanced Mitochondrial Calcium Uptake During Chronic β-adrenergic Stimulation Causes Maladaptive Remodeling and Impaired Left Ventricular Function Independent of Cyclophilin D-mediated Mitochondrial Permeability Transition
Authors: Garbincius Joanne F , Luongo Timothy S , Lambert Jonathan P , Mangold Adam S , Murray Emma K , Hildebrand Alycia N , Jadiya Pooja , Elrod John W
Published: October 2020

The mitochondrial calcium uniporter (MCU) forms the pore of the mitochondrial calcium uniporter channel (mtCU) and is required for rapid mitochondrial Ca
2+
(
m
Ca
2+
) uptake. MCU is necessary to increase cardiac energetics to fuel an increase in cardiac contractility during acute sympathetic stimulation. However, little is known about how MCU-dependent Ca
2+
flux may contribute to the heart’s adaptations to chronic stress. We therefore compared mice with adult cardiomyocyte (ACM)-specific loss (
Mcu
fl/fl
; Mcu-cKO) or gain (CAG-CAT-MCU; MCU-Tg) of MCU function to examine the role of MCU-dependent
m
Ca
2+
uptake in a model of chronic catecholamine overload.
In vitro
characterization of ACMs confirmed that MCU overexpression enhanced and
Mcu
deletion inhibited acute
m
Ca
2+
uptake. Neither loss nor gain of MCU function altered baseline contractile function
in vivo
. In αMHC-MCM control mice, fractional shortening was transiently increased after 2 days of isoproterenol infusion. This initial increase in contractility was attenuated in MCU-cKO mice. In contrast, MCU-Tg mice exhibited decreased fractional shortening at 7 and 14 days of isoproterenol infusion. This detrimental effect on contractile function was associated with increased LV dilation, HW/BW ratio, and lung edema. MCU-Tg cardiomyocytes
in vitro
exhibited increased ROS production and a trend towards increased cell death upon elevation of cytosolic Ca
2+
with ionomycin. These data prompted us to test the hypothesis that isoproterenol-induced contractile dysfunction in MCU-Tg hearts is caused by cardiomyocyte dropout due to
m
Ca
2+
overload and mitochondrial permeability transition. However, genetic deletion of the mPTP component cyclophilin D did not prevent the decline in contractile function, diminish cardiomyocyte death, or attenuate LV remodeling in MCU-Tg animals during chronic isoproterenol infusion. We conclude that although mtCU-dependent
m
Ca
2+
uptake is essential for early energetic adaptations to high adrenergic load, under conditions of chronic adrenergic stress it is maladaptive and predisposes to heart failure. Our data suggest that this maladaptive response occurs via mechanisms independent of cyclophilin D-mediated permeability transition.
Abstract 507: Activation of the Classically Pro-Apoptotic Death Receptor 5 Promotes Physiological Hypertrophy and Cardiomyocyte Survival
Authors: Thomas Toby , Tanner Miles , Grisanti Laurel
Published: October 2020

Heart failure is hallmarked by a combination of cardiomyocyte hypertrophy and death. Apoptosis, one of the primary mechanisms of cell death, occurs through finely tuned extrinsic or intrinsic pathways. Of the mediators involved in extrinsic apoptotic signaling, some have been extensively studied, such as tumor necrosis factor ((TNF)-α), while others have been relatively untouched. One such receptor is Death Receptor 5 (DR5) which, along with its ligand TNF-Related Apoptosis Inducing Ligand (TRAIL), have recently been implicated as a biomarker in determining the progression and outcome in patients following multiple heart failure etiologies, suggesting a novel role of DR5 signaling in the heart. These studies suggest a potentially protective role for DR5 in the heart; however, the function of TRAIL/DR5 in the heart has been virtually unstudied. Our goal was to explore the role of TRAIL/DR5 in cardiomyocyte hypertrophy and survival with the hypothesis that DR5 promotes cardiomyocyte survival and growth through non-canonical mechanisms. Mice treated with the DR5 agonist bioymifi or a DR5 agonist antibody, MD5-1, were absent of cell death, while an increase in hypertrophy was observed without a decline in cardiac function. In isolated cardiomyocytes, this pro-hypertrophic phenotype was determined to operate through MMP-dependent cleavage of HB-EGFR, leading to transactivation of EGFR and ERK1/2 signaling. To determine the role of DR5 in heart failure, a chronic catecholamine administration model was used and DR5 activation was found to decrease cardiomyocyte death and cardiac fibrosis. ERK1/2, a well characterized pro-survival, pro-hypertrophic kinase is activated in the heart with DR5 agonist administration and may represent the mechanistic link through which DR5 is imparting cardioprotection. In summary, DR5 activation promotes cardiomyocyte hypertrophy and survival and prevents cardiac fibrosis via a non-canonical MMP-EGFR-ERK1/2 pathway. Taken together, these studies identify a previously undetermined role for DR5 in the heart and identify novel therapeutic target for the treatment of heart failure.
Abstract 511: Transcriptomic Analysis of End-stage Human Heart Failure Highlights Strong Interaction Effect Between Race and Diabetes
Authors: Potter Luke A , Pepin Mark E , Ha Chae-myeong , Bakshi Sayan , Wende Adam R
Published: October 2020

African Americans (AA) have an elevated risk for cardiovascular diseases compared to Caucasian Americans (CA), including heart failure (HF). Type 2 diabetes (T2D) is a major risk factor for HF that also disproportionately affects AA. These health disparities and others reduce life expectancy ~3.5 y for AA compared to CA. While prior studies have explored the connection between diabetes and heart failure, the current understanding of HF pathogenesis is based almost exclusively from studies of CA, whereas those considering race have been either epidemiologic or narrow in focus. The purpose of this study was to examine things from a different angle through the use of genome-wide RNA-sequencing to uncover how diabetes differentially or similarly affects end-stage heart failure in AA vs CA. To accomplish this, human biopsy samples were obtained from 32 age and diabetes status (T2D or non-diabetic (ND)) matched male patients undergoing left ventricle assist device surgeries
(n =
8: CA-ND, CA-T2D, AA-ND, AA-T2D). Differential expression analysis was then performed using generalized linear modeling to control for clinical covariates including hypertension and coronary artery disease. Results of T2D vs ND in AA patients showed a greater number of differentially expressed genes (DEGs,
P
< 0.05,
Abstract 519: Talin is Required for Normal Adult Heart Function
Authors: Cho Yoshitake , Li Ruixia , Manso Ana M , Ross Robert S
Published: October 2020

Talin (Tln) is a component of muscle costameres that links integrins to other components of the cellular cytoskeleton and plays an important role in maintaining the cellular integrity of cardiac myocytes (CM). There are two talin genes, Tln1 and Tln2, expressed in the heart. Tln1 is ubiquitously expressed, and Tln2 is dominantly expressed in CM. In our previous study, we show that the global deletion of Tln2 in mice (T2KO) caused no structural or functional changes in the heart, presumably because CM Tln1 became up-regulated. However, we found that mice lacking both CM Tln1 and Tln2 exhibit cardiac dysfunction by 4 weeks (w) of age with 100% mortality by 6 months (m), showing Tln plays an essential role in cardiac development and in maintaining cardiac function. In this study, we produced a tamoxifen (Tamo)-inducible mouse model in which Tln1 could be explicitly reduced in the adult CM (T1icKO), and then generate T1icKO:T2KO (T1/2dKO), so that the function of Tln could be assessed in the postnatal heart.

T2KO and Tln1/2dKO mice were injected with Tamo at 8w. Echocardiograms were performed to evaluate cardiac function up to 8w post-Tamo injection. While T2KO mice showed normal cardiac function, T1/2dKO exhibited a gradual decrease in function post-Tamo injection. At 8w post-Tamo injection, T1/2dKO mice showed cardiac hypertrophy, fibrosis, and heart failure. To understand the mechanism by which deletion CM talin leads to cardiac dysfunction, left ventricular tissue protein lysates from T2KO and T1/2dKO mice at 4w post-Tamo when cardiac function (echo) and structure were preserved in dKO. The protein lysates were subjected to quantitative mass spectrometry analysis. We found there are 1,100 proteins differentially expressed in T2KO and T1/2dKO hearts. Pathway analysis was performed, and the results showed that proteins involved in vesicle transport, protein folding, and innate immunity are most up-regulated in the T1/2dKO heart. Taken together, our results show that Tln is required for maintaining proper cardiac function in the adult heart. The deletion of Tln in CM results in the up-regulation of multiple intracellular pathways, and we are currently studying the role of each pathway in the pathogenesis of heart failure induced by CM Tln deletion.
Abstract 522: Impaired Inside-out Force Transmission in Hipsc-cardiomyocyte Model of Duchenne Muscular Dystrophy Cardiomyopathy
Authors: Pardon Gaspard , Birnbaum Foster , Eguchi Asuka , BLAU Helen M
Published: October 2020

Duchenne Muscular Dystrophy (DMD) is a lethal X-chromosome linked disease that affects ~1:3500 boys and culminates in heart failure in early adulthood. DMD results from >200 possible dystrophin mutations. The lack of dystrophin disrupts the anchoring of the sarcomere to the extracellular matrix (ECM), impairing cardiomyocyte function and cardiac contraction. With disease progression, the heart tissue stiffness increases as fibrosis progresses and a dilated cardiomyopathy phenotype develops. We hypothesize that disease progression accelerates because of a positive feedback loop involving fibrotic stiffening and mechanosensing. Our preliminary results show that single human-derived pluripotent stem cell (hiPSC) cardiomyocytes (CMs) with DMD mutations have a dramatically reduced ability to produce force compared to isogenic controls on stiffer substrates mimicking a fibrotic state, but not on soft healthy substrates. This stiffness-dependent contractile deficiency correlates with an increase in reactive oxygen species (ROS) and mitochondrial dysfunction, as well as other markers of cellular stress response and senescence. Here, we ask how stiffness affects the progression of DMD cardiomyopathy and aim to draw a link between the lack of dystrophin and force production deficiency in hiPSC-CMs with or without DMD mutations in an isogenic background. Using a novel assay and algorithm, we simultaneously measure extracellular force production by traction force microscopy (TFM) and single sarcomere dynamics (SSD) in single hiPSC-CMs adhered onto ECM micropatterns on top of a hydrogel of stiffness matching that of healthy (~10kPa) or fibrotic (~35kPa) tissue. We induce the single hiPSC-CMs to adopt a physiologic elongated 1:7 aspect ratio using microcontact printing of ECM protein. Using this platform, we determine how the lack of dystrophin impacts sarcomere architecture, sarcomere contractility, and force generation in the etiology of DMD cardiac disease.
Abstract 523: Analysis of Mesenchymal Stem Cell Proteomes In Situ in the Ischemic Heart
Authors: Yang Junjie , Han Dunzheng , Qin Gangjian
Published: October 2020

Cell therapy for myocardial infarction is promising but largely unsuccessful partially due to a lack of mechanistic understanding. Techniques enabling identification of stem cell-specific proteomes
in situ
in the injured heart may shed light on how the administered cells respond to the injured microenvironment and exert reparative effects. To identify the proteomes of the transplanted mesenchymal stem cells (MSCs) in the infarcted myocardium, we sought to engineer a mutant methionyl-tRNA synthetase (MetRS
L274G
) in MSC, which charges the methionine analogue azidonorleucine (ANL) to tRNA and subsequently to nascent proteins, permitting isolation of ANL-labeled MSC proteomes from ischemic hearts by ANL-alkyne based click reaction. Murine MSCs were transduced with lentivirus MetRS
L274G
and supplemented with ANL; the ANL-tagged nascent proteins were visualized by bio-orthogonal non-canonical amino-acid tagging, spanning all molecular weights and by fluorescent non-canonical amino-acid tagging, displaying strong fluorescent signal. Then, the MetRS
L274G
-transduced MSCs were administered to the infarcted or Sham heart in mice receiving ANL treatment. The MSC proteomes were isolated from the left ventricle by click reaction at days 1, 3, and 7 after cell administration, identified by LC/MS. Among all identified proteins (in Sham and MI hearts, three time-points each), 648 were shared by all 6 groups, accounting for 82±5% of total proteins in each group, and their GO terms are enriched under mitochondrion, extracellular exosomes, oxidation-reduction process and poly(A) RNA binding. Notably, 35, 131 and 84 proteins were significantly up-regulated and 12, 38 and 27 proteins were down-regulated in the infarcted vs. Sham heart at the three time-points, respectively; these proteins are pronounced in the GO terms of extracellular microvesicles, inflammatory response and apoptosis and in the KEGG pathways of complements and coagulation cascades, lysosomes, and regulators of actin cytoskeleton. MetRS
L274G
expression allows successful identification of MSC-specific nascent proteins in the infarcted hearts, which reflect the functional states, adaptive response, and reparative effects of MSCs that may be leveraged to improve cardiac repair.
Abstract 525: Adult Inducible Deletion of Endothelial Hypoxia-inducible Factor-2α Exaggerates Myocardial Infarction Induced Heart Failure and Cardiac Microvascular Barrier Dysfunction
Authors: Ai Lizhuo , Liu Lifeng , wu rongxue , Sitikov Albert , Harrison Devin , Besser Stephanie A , Fang Yun , Liao james K , Wu Rongxue
Published: October 2020

Background:
Myocardial ischemia occurs during myocardial infarction results in the stabilization of Hypoxia-inducible factors (HIFs). Hif2α expresses profoundly in vascular endothelial cells (EC), and its embryonic deletion increases vessel permeability. It has been shown that HIF2a is protective from renal and pulmonary injury. However, the direct role of ecHIF2α in ischemia heart disease is unknown. We hypothesized that ecHIF2a expression in response to myocardial infarction (MI) protects cardiac barrier dysfunction and against heart failure.

Methods and Results:
We generated the Inducible endothelial-specific knockout mice (ecHIF2a
-/-
) by crossing Hif2a
flox/flox
mice with Cre ERT2 mice under the VE-cadherin promoter. Followed with MI, ecHIF2a
-/-
mice displayed worsened cardiac function determined by echocardiography, and they had increased mortality as compared to the controls. In vitro, we used primary mouse cardiac microvascular endothelial cells (mCMVEC) from ecHIF2a
-/-
mouse hearts. We found that under hypoxia condition or 1mM Dimethyloxalylglycine treatment, the deficiency of HIF2a in the mCMVEC increased endothelial permeability determined by trans-endothelial electrical resistance. The knocking down of HIF2a in HUVECs induced by a HIF2a siRNA led to impaired tube formation accessed by the significant reduction in total node counts, junctions, meshes, and full tube length compared to control-siRNA treated cells. HIF2α deletion and hypoxia both reduced endothelial cell migration, and interestingly, the retarded HIF2α-/- ECs migration seems to be independent of hypoxia. Moreover, apoptosis assay showed that ecHIF2a
-/-
ECs increased cell early apoptotic stage compared to WT in hypoxic conditions, but not in normoxia indicating the critical role of HIF2α in ECs survival during cardiac ischemia. Finally, several increased markers of inflammation, such as ICAM-1 and VCAM-1, are associated with HIF2a deletion.

Conclusion:
These data revealed an essential role of HIF2α in protecting cardiac remodeling in response to MI, which might through promoting endothelial cell migration, barrier function, as well as vascularization. Thus, HIF2α is a potential therapeutic target in the treatment of ischemic heart disease.