bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract P2044: Silencing The LncRNA
Vesper
During Right Ventricle Pressure Overload Worsens Hypertrophic Remodeling And Function
Authors: Kocken Jordy M , Mendes-Ferreira Pedro , del Marmol Henry , Davalan Tim , Figuinha Videira Raquel , Leite-Moreira Adelino F , da Costa Martins Paula A
Published: October 2023

Pulmonary arterial hypertension (PAH) is a rare disease that includes familiar and idiopathic forms. Increased pressure in the pulmonary artery leads to pressure overload of the right ventricle (RV) and subsequent hypertrophic remodeling to maintain cardiac output (CO). While many therapies are available for the hypertrophic left ventricle (LV), the RV is known to involve distinct remodeling pathways and unfortunately, these are poorly understood, and no cure is available. To identify new regulatory mechanisms, total RNA sequencing was performed on hypertrophied mouse RV tissue. Focusing at differentially expressed long non-coding RNAs (lncRNAs), one specifically,
Gm38399
, was observed to be consistently upregulated in the diseased RV compared to healthy controls. Compared to LV tissue, there was a similar expression at baseline, but interestingly, no increase in expression during LV hypertrophy. Therefore, we named this lncRNA right
VE
ntricular
S
pecific
P
ressure ov
ER
load (
Vesper
). To elucidate the mechanism, we determined the subcellular localization of
Vesper
, by subcellular fractioning followed by qPCR. Using
Xist
as nuclear, and
Gapdh
as cytoplasmic control, we found
Vesper
to be entirely nuclear. Furthermore, we were able to silence
Vesper
in vitro
by using a specific GapmeR. Not only Vesper was silenced, but we also found two neighboring genes to be affected, namely
Nav1
and
Phlda3
. Interestingly, these genes were also differentially expressed in the diseased RVs. To determine the mechanism
in vitro
, chromatin isolation by RNA purification (ChIRP) was performed and the crosslinked RNA, DNA, proteins stored for further analysis. We also treated mice that underwent pulmonary artery banding (PAB) or sham surgery, with a weekly intraperitoneal injection of 10 mg/kg bodyweight GapmeR or a vehicle control. After 4 weeks, the mice underwent hemodynamic analysis before the RV tissue was isolated for histology and molecular analysis. Surprisingly, silencing of Vesper exacerbated pathologic RV remodeling, also in mice that received sham surgery. While further investigation is needed to understand the role of Vesper in PAH, our results so far suggest that expression of
Vesper
is necessary to maintain RV function during pressure overload.
Abstract P2048: New Insights Into The Role Of The Glycocalyx Components In Heart Failure Induced By Pressure Overload.
Authors: Thota Lakshmi Narasimha , Potje Simone , Bendhack Lusiane , Carvalho-de-Souza Joao , Chignalia Andreia
Published: October 2023

Heart failure (HF) is a complex disease with multifactorial etiology. The degradation of the glycocalyx is a process thought to contribute to the progression of HF. The relative individual contribution of glycocalyx components to HF progression is unclear. Previous studies have shown that the expression of glypican 1 (Gpc1), a glycocalyx component, is reduced after aortic banding. Herein, we sought to determine if Gpc1 participates in the progression of HF induced by pressure overload and the associated mechanisms.

Methods:
Male, 5-8 weeks old, WT and Gpc1 knockout mice (Gpc1KO) were submitted to transaortic constriction (TAC) or sham procedure. Heart function was assessed by echocardiography; heart remodeling was assessed by histological analysis; heparan sulfate and glypican 1 content was assessed by immunofluorescence; the expression of ANP and myosin was assessed by immunoblotting.

Results:
Gpc1KO showed preserved heparan sulfate content in heart sections. Gpc1KO showed cardiac hypertrophy as evidenced by increased left ventricle mass (173.75mg
vs.
123.96 mg in WT; p=0.004; n=10), left ventricle wall thickness (1.43mm
vs
. 1.13mm in WT; p=0.033; n=10), intraventricular septal end-diastolic thickness (1.83mm
vs.
1.62mm in WT; p=0.001; n=11) and decreased cardiomyocyte cross-sectional area (203.86μm2
vs.
248.44μm2; p<0.0001; n=5). This was associated with increased stroke volume (52.89±2.1μL vs 46.42±2.0 μL; p=0.038, n=10), cardiac output (26.39 mL/min
vs.
20.32 mL/min in WT), calcium deposits, ANP (0.86±0.02 vs. 0.57± 0.03; p<0.0001; n=5) and myosin (0.71±0.1
vs.
0.50±0.01 in WT; p=0.03; n=5) content in the heart. Gpc1KO were prone to TAC-induced HF as shown by decreased ejection fraction (34.37%
vs
. 58.41% in WT; p=0.047; n=3) and stroke volume (35.24μL
vs.
44.60 μL in WT; p=0.05, n=3) 3 weeks after TAC. Moreover, Gpc1KO showed increased mortality rate, not surviving 5 weeks post-TAC.

Conclusions:
Gpc1KO shows basal cardiac remodeling associated with changes in calcium dynamics and increased contractility. The increased susceptibility of Gpc1KO to TAC-induced HF seems to be independent of glycocalyx degradation. Further studies are required to understand the mechanisms whereby Gpc1 regulates the progression of TAC-induced HF.
Abstract P2049: Myosin Heavy Chain-7 E848G Mutation-induced Sarcopenia And Hypocontractility In Induced Pluripotent Stem Cell Model Of Hypertrophic Cardiomyopathy Are Rescued By Muscle Ring Finger 1 Ablation
Authors: Loiben Alexander M , Friedman Clayton E , Chen Wei-Ming , Yang Kai Chun
Published: October 2023

Hypertrophic cardiomyopathy (HCM) presents with idiopathic left ventricular hypertrophy and occasionally systolic dysfunction. In a human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) model of HCM, we previously reported the pathogenic
MYH7
E848G variant increased hiPSC-CM size and impaired contractility. To elucidate the mechanisms by which the E848G variant causes HCM, we now examined cardiac tissue from a
MYH7
wt/E848G
patient. We found reduced expression of the following sarcomeric proteins: β-myosin heavy chain (βMHC) (97.8 ± 1.1% reduction), α-sarcomeric actinin (αSA) (84.8 ± 7.3%), and ventricular myosin light chain (MLC-1v) (45.9 ± 13.9%) relative to healthy patient tissue. Isogenic
MYH7
wt/E848G
hiPSC-CMs also had reduced protein expression of βMHC (22.8%) and αSA (24.5%) relative to
MYH7
wt/wt
hiPSC-CMs and unchanged mRNA expression. These results suggest
MYH7
E848G HCM induces broad sarcomere component deficiency. We tested hiPSC-CM contractility using single cell traction force microscopy (TFM) and engineered heart tissues (EHT). Single isogenic
MYH7
wt/E848G
hiPSC-CMs had lower maximum twitch force (80 ± 12 nN) than
MYH7
wt/wt
hiPSC-CMs (150 ± 20 nN) by TFM. Isogenic
MYH7
wt/E848G
EHTs had lower maximum twitch force (118.9 ± 23.7 μN) than
MYH7
wt/wt
EHTs (287.4 ± 27.7 μN). Because MuRF1, an E3 ubiquitin-protein ligase, is known to target βMHC for proteasomal degradation, we hypothesized MuRF1 mediates the sarcopenic and hypocontractile phenotype. Genetic ablation of
TRIM63
(encoding MuRF1) significantly reduced
MYH7
wt/E848G
hiPSC-CM cell size by flow cytometry (6.8 ± 1.7%).
MYH7
wt/E848G
TRIM63
-/-
hiPSC-CMs increased protein expression of βMHC (154.7 ± 51.9%), αSA (44.9 ± 25.6%), and MLC-1v (246.9 ± 57.3%) relative to
MYH7
wt/E848G
TRIM63
+/+
hiPSC-CMs.
MYH7
wt/E848G
TRIM63
-/-
had significantly higher maximum twitch force by TFM (133 ± 14 nN) and EHTs (178.2 ± 9.8 μN) than
MYH7
wt/E848G
TRIM63
+/+
by TFM (67 ± 8.0 nN) and EHTs (118.9 ± 23.7 μN). Our results implicate sarcopenia in the pathogenesis of
MYH7
E848G HCM and identify MuRF1 as a potential novel therapeutic target for HCM. Further study will determine if these findings are generalizable to other pathogenic HCM variants in
MYH7
and other sarcomeric genes.
Abstract P2052: Fibroblast-specific TGF-b Signaling Protects The Infarcted Myocardium From Adipose Tissue Infiltration
Authors: Tuleta Izabela , Venugopal Harikrishnan , Humeres Claudio , Hernandez Silvia C , Kubota Akihiko , Hanna Anis , Frangogiannis Nikolaos G
Published: October 2023

Background and Objectives:
Repair of the infarcted heart requires timely phenotypic transitions of fibroblasts, the central effector cells involved in scar formation and matrix remodeling. TGF-b superfamily members are critical regulators of fibroblast phenotype, acting through TGF-b receptors (TbR) and downstream activation of Smad-dependent and Smad-independent cascades. We have previously demonstrated that fibroblast-specific Smad3 plays a central role in repair of the infarcted heart; however, the role of TGF-b/TbR signaling in regulation of infarct fibroblast transitions has not been investigated. In the current study we examine the role of fibroblast-specific TGF-b signaling in repair of the infarcted heart, using mice with inducible fibroblast-specific disruption of TbRII (FTbRIIKO mice), the only type 2 receptor mediating the effects of all 3 TGB-b isoforms.

Findings:
FTbRIIKO animals exhibited increased mortality after myocardial infarction (MI), caused by cardiac rupture. In comparison with TbRII fl/fl mice, TbRII KO mice had significant thinning of the anterior wall 28 days after MI, without significant differences in ventricular function. Fibroblast-specific TGF-b signaling loss did not affect myofibroblast infiltration 7 days after MI. 28 days after MI, brightfield and polarized microscopy showed that, although scar size was comparable between the groups, collagen content and the width of collagen fibers were reduced within infarcted zones of FTbRIIKO vs. FTbRII fl/fl animals. Moreover, FTbRIIKO mice exhibited a striking deposition of adipocytes, occupying up to 40% of the infarct zones (fatty infiltration: FTbRIIKO, 28.7±6.2% vs floxed 0±0%, p<0.001, n=6-8). Infarct fibroblasts harvested from FTbRIIKO mice 7 days after MI had increased expression of adipocyte genes, such as perilipin, leptin receptor, and PPARgamma.

Conclusions:
Fibroblast-specific TGF-β signaling protects the infarcted heart from cardiac rupture and prevents fatty infiltration of the infarct. These effects may reflect critical actions of TGF-bs on fibroblast phenotypic transitions and inhibition of fibroblast to adipocyte conversion.
Abstract P2053: Bag5 Plays A Critical Role In The Regulation Of Cellular Homeostasis Through Fine-tuning Of Cellular Protein Quality Control
Authors: Mukker Avni , Kashyap Shiridhar , Gupta Manish K
Published: October 2023

Background:
Cardiac hypertrophy is one of the heart's adaptive responses, which may play a compensatory role in enhancing cardiac function during stress conditions. However, prolonged hypertrophy condition can lead to the progression of cardiac dysfunction and heart failure. Cellular chaperones and co-chaperones play a critical role in maintaining cellular homeostasis by regulating cellular protein quality control. A Bcl2 binding protein BAG5 acts as a co-chaperone to heat shock protein 70 and is known to be upregulated during oxidative stress. A recent study suggests that mutation of the BAG5 gene induces cardiac dysfunction by promoting dilated cardiomyopathy and arrhythmia. However, its role in cardiac hypertrophy is not clear.

Method and Results:
This study explores the BAG5 function through a protein-protein interaction study by immunoprecipitation and mass spectroscopy. Further, the role of BAG5 in cellular protein quality control and cardiac hypertrophy was tested using cardiomyocytes. Our protein interaction study suggests that BAG5 interacts with several cellular proteins involved in the biological process like Golgi-associated vesicular transport, fatty acid degradation, endoplasmic reticulum-assisted protein folding, chaperone-mediated protein degradation, and deubiquitinating process. Further, we found that knockdown of BAG5 causes induction of cellular hypertrophy, and overexpression of BAG5 reduces PE and ISO-induced cellular hypertrophy. Additionally, we found that BAG5 maintains a balance of cellular protein quality control, and knockdown of BAG5 causes upregulation of cellular autophagy

Conclusion:
BAG5 plays a critical role in maintaining cellular homeostasis and is protective during cardiac hypertrophy. Additionally, the reduction of BAG5 protein can promote maladaptive autophagy.
Abstract P2055: Long-term Elevation Of Cardiomyocyte Protein O-GlcNAc Levels Induces Cardiac Hypertrophy And Reduced Mitochondrial Function With Preserved Systolic Contractility
Authors: Ha Chae-Myeong , Bakshi Sayan , Brahma Manoja , Potter Luke , Chang Samuel , Chatham John C , Wende Adam R
Published: October 2023

The severity and development of cardiovascular disease (CVD) can be affected by lifestyle and metabolic diseases, which can impact various mechanisms, including post-translational modifications (PTM). A specific PTM, known as protein O-linked β-N acetylglucosamine modification (O-GlcNAc), has been linked to both physiological responses and pathological progression of heart failure. This study was aimed to test whether sustained cardiac protein O-GlcNAc of proteins in cardiomyocytes contributes to cardiac adaptations or is sufficient to progress toward pathophysiology. Specifically, we generated transgenic mice overexpressing a naturally occurring dominant-negative O-GlcNAcase (dnOGA) in an inducible and cardiomyocyte-specific manner (dnOGAh). We induced dnOGA in male and female 8-10-weeks-old mice and examined the effects of 2-weeks (2wk) and 24-weeks (24wk) dnOGA overexpression, which resulted in a 1.8-fold increase in protein O
-
GlcNAc levels (
P
<0.01). The results showed that a 2wk increase in protein O-GlcNAc levels did not impact heart weight or function; however, 24wk of elevated protein O-GlcNAc led to cardiac hypertrophy (+19.8%,
P
<0.01), fibrosis (M. Trichrome; +578%,
P
<0.005), and diastolic dysfunction (E/A; +314%,
P
<0.001). Despite several changes in gene expression associated with CVD, systolic function was maintained in 24wk dnOGA overexpression. mRNA-seq analysis revealed several gene signatures changed as early as 2wk of dnOGA that progressed at 24wk, including reduction of mitochondrial oxidative phosphorylation, fatty acid and glucose metabolism pathways (
Abstract P2058: Mesenchymal Stem Cells Reduce Endothelin-1 Induced Hypertrophy In Hypoplastic Left Heart Syndrome Patients’ Cardiomyocytes
Authors: Fu Xuebin
Published: October 2023

Introduction:
Hypoplastic left heart syndrome (HLHS) is one of the most difficult congenital cardiovascular conditions. There are no proven therapeutic strategies for systemic right ventricular (RV) heart failure till now.

Hypothesis:
We investigated whether mesenchymal stem cells (MSCs) can ameliorate heart failure (HF) in HLHS patients.

Methods & Results:
We analyzed the cardiac tissues of patients with HLHS (N = 20) and healthy donors (N = 12). Compared to the controls, the cross-sectional area of cardiomyocytes determined by wheat germ agglutinin staining significantly increased in the HLHS hearts. Furthermore, quantitative RT-PCR (qRT-PCR) confirmed the expression of fetal genes, including atrial natriuretic factor (ANF), natriuretic peptide B (BNP), and myosin heavy chain-β (MHC-β), were significantly upregulated in the HLHS. The results indicated severe pathological hypertrophy in HLHS patients. To investigate our hypothesis, we employed HLHS patients’ iPSCs and differentiated them into cardiomyocytes (iCMs). Differentiated HLHS-iCMs were confirmed by expression of the cardiac markers, cardiac troponin T.
In vitro
, 10nM Endothelin-1 (ET-1) stimulation successfully induced cardiac hypertrophy confirmed by cell size and fetal gene expression. Interestingly, co-cultured HLHS-iCMs with mesenchymal stem cells (MSCs) in the trans-well plates reduced the ET-1 induced hypertrophy. The results indicated that secretome from MSCs played a critical role in referring to the anti-hypertrophic effects. Compared to the control conditioned media from fibroblasts, GDF-15 was highly expressed in the MSC-conditioned medium. GDF-15 alone also reduced ET-1 induced hypertrophy in the HLHS-iCMs.

Conclusions:
In HLHS patients, RV hypertrophy is a hallmark of heart failure. MSCs potentially inhibited hypertrophic remodeling in HLHS patient-specific cardiomyocytes through beneficial secretomes, such as GDF-15.
Abstract P2060: Gja1-20k Expression Increases With Left Ventricular Mechanical Unloading In Patients With Arrhythmogenic Cardiomyopathy And Advanced Heart Failure
Authors: Taylor Lindsey A , Valdez Steven , Kyriakopoulos Christos , LING JING , Selzman Craig , Caine William , Drakos Stavros G , Shaw Robin M , Palatinus Joseph
Published: October 2023

GJA1-20k, the internally translated isoform of the gap junction protein Connexin-43 (Cx43) is required for trafficking of the full length Cx43 to the membrane. We recently found that GJA1-20k expression is reduced in patients and mice with arrhythmogenic cardiomyopathy (ACM), and that gene therapy-mediated introduction of GJA1-20k in a mouse model of ACM rescues Cx43 trafficking to the intercalated disc and reduces arrhythmia burden, indicating that loss of GJA1-20k contributes to arrhythmogenesis in ACM. Here, we examined cardiac muscle from patients with a confirmed diagnosis of ACM for GJA1-20k expression before and after left ventricular assist device (LVAD) support. The goal of this study was to determine if left ventricular (LV) unloading benefits endogenous expression of this critical trafficking protein. Cardiac tissue was collected from consecutive, prospectively enrolled patients undergoing LVAD implantation or heart transplantation in hospitals comprising the Utah Cardiac Recovery program and donor patients from hospitals throughout the Intermountain West. Samples were prepared for analysis using a standard lysis buffer and analyzed via Western Blotting using antibodies to GAPDH and Cx43-CT. Consistent with prior findings, cardiac muscle samples from patients with ACM had decreased GJA1-20k expression relative to muscle from healthy donor hearts not allocated for transplantation. However, tissue obtained from the same ACM patients post LVAD support (at the time of heart transplantation) revealed a large and significant increase in GJA1-20k expression compared to the pre LVAD timepoint (1 +/- 0.5 vs 10.2+/- 1, p=0.0013, n=3 ACM pre/post). In contrast to patients with ACM, patients with non-ischemic cardiomyopathy (NICM) that underwent LVAD implantation had no significant change in GJA1-20k expression after LV unloading (1+/- 0.5 vs 1.4+/- 0.7, p= 0.424, n=4 NICM pre/post). These data indicate that LV mechanical unloading increases GJA1-20k expression in hearts of patients with known ACM. Further work will focus on how mechanical unloading regulates GJA1-20k expression and whether mechanical unloading is sufficient to recover Cx43 trafficking and limit arrhythmias in ACM.
Abstract P2072: Chronic Treatment With An Androgen Receptor Antagonist Promotes Maladaptive Structural And Functional Cardiac Remodeling In Aging Male Mice
Authors: Banga Shubham , Howlett Susan E
Published: October 2023

Testosterone levels decrease with age in men, while the risk for cardiovascular diseases (CVD) increases dramatically. Indeed, low circulating testosterone levels in men are associated with diseases such as heart failure. Testosterone exerts its effects via androgen receptors, which are even present in the heart. In addition, androgen receptor antagonists are used to treat prostate cancer in older men who may also have CVD. We investigated the effects of the androgen receptor antagonist flutamide on cardiac structure and function in aged mice. Twenty-month-old male C57BL/6 mice were treated with flutamide for 90 days (slow-release pellet implant; ~20mg/kg/day).
In-vivo
heart structure/function was assessed using echocardiography and then hearts were Langendorff-perfused to assess load-independent ventricular function
ex-vivo
. Androgen receptor blockade via flutamide caused maladaptive ventricular remodeling.
In-vivo
studies showed that flutamide-treated mouse hearts had smaller left ventricular inner diameters when compared to vehicle-treated mice (
e.g.
, diastolic: 4.7 ± 0.1 vs. 4.4 ± 0.1 mm; p=0.01; n=8,7). Flutamide also caused left ventricular (LV) atrophy with thinner posterior walls (0.91 ± 0.07 vs. 0.74 ± 0.04 mm; p=0.05) and reduced LV mass when compared to vehicle controls (140 ± 12 vs. 105 ± 6 mg; p=0.03).
Ex-vivo
functional assessment showed a marked reduction in LV developed pressure in the flutamide-treated mice (111 ± 11 vs. 71 ± 3 mmHg; p<0.01). These mice also had significantly slower rates of LV pressure rise (+dP/dT=2219 ± 263 vs. 1406 ± 95 mmHg/s; p<0.01) as well as LV pressure decay (-dP/dT=-1975 ± 263 vs. -1327 ± 132 mmHg/s; p=0.04). This indicates that flutamide-treated mice had defects in both systolic and diastolic cardiac function. These results demonstrate that suppressing the effects of testosterone by blocking androgen receptors promotes maladaptive structural remodeling of the left ventricle and promotes systolic and diastolic dysfunction in hearts from aged male mice. This study suggests that chronic treatment with androgen receptor antagonists may induce cardiac dysfunction in older men, which has implications for individuals taking these medications for prostate cancer treatment.
Abstract P2074: Site-specific Phosphorylation Of Vinculin Regulates N-cadherin Junction Assembly
Authors: Radice Glenn , Li Xiaofei , Wortelboer Rainy , McLain Callie
Published: October 2023

Introduction:
During physiological and pathological growth, cardiomyocytes adapt and remodel in response to changes in mechanical load. The cytoskeleton plays a central role in tissue remodeling as it both senses mechanical stress and mediates structural remodeling which affects the functional response within the cardiomyocyte. Abl kinase-dependent vinculin (VCL) phosphorylation at tyrosine (Y) residue 822 (pVCL-Y822) has been implicated in force-induced cytoskeletal remodeling and adhesion strengthening at cadherin junctions. However, the functional significance of VCL phosphorylation in the working myocardium remains unknown.

Objective:
To determine the role of vinculin-mediated mechanotransduction in cardiac development, homeostasis, and disease.

Methods and Results:
Using a phospho-specific antibody, we found that pVCL-Y822 correlates with dynamic junction remodeling in embryonic cardiomyocytes which declines in the postnatal heart when N-cadherin junctions assemble at the intercalated disc. Notably, pVCL-Y822 is upregulated in border zone cardiomyocytes following myocardial infarction. To investigate VCL-mediated mechanotransduction in the heart, CRISPR-mediated genome editing was used to mutate the tyrosine at position 822 to a non-phosphorylatable phenylalanine (F) in the mouse
Vcl
gene.
Vcl Y822F
mice were born in the expected Mendelian frequency and are viable. Blocking VCL phosphorylation causes a preferential reduction of mutant VCL protein at the myocyte termini together with the N-cadherin-catenin adhesion complex. Whereas, α5/β1 integrin and fibronectin are both increased along the lateral border of the
Vcl Y822F
postnatal cardiomyocytes.
Vcl Y822F
mice exhibit reduced cardiac function with age; however, cardiac remodeling is attenuated in the mutant hearts.

Conclusion:
This novel animal model demonstrates how blocking vinculin Y822 phosphorylation affects the balance between cadherin adhesions and integrin adhesions and thereby highlights the importance of understanding the crosstalk between the two adhesion systems and its implications for disease pathogenesis.
Abstract P2082: Thrombosis In The Coronary Microvasculature May Be Responsible For Impaired Cardiac Relaxation And Diastolic Dysfunction
Authors: Paul Rouault , Guimbal Sarah , Cornuault Lauriane , Foussard Ninon , Bourguignon Célia , Grouthier Virginie , Choveau Frank , Benoist David , Gadeau Alain-Pierre , Couffinhal Thierry , Renault Marie-Ange
Published: October 2023

Introduction:
Heart Failure with Preserved Ejection Fraction (HFpEF) is proposed to be caused by endothelial dysfunction in cardiac small vessels. We previously identified Hhipl1,as a gene upregulated in the coronary vasculature of Leptin receptor deficient mice (Leprdb/db) a well-established mouse model of HFpEF. Importantly, Hhipl1 encodes for a decoy receptor of Desert Hedgehog (DHH) which is known to be critical for endothelial integrity.

Objective:
Our objective is to investigate the functional consequences of impaired Hedgehog (HH) signaling in the adult heart in order to identify novel mechanisms underlying the development of diastolic dysfunction.

Method:
Cdh5-Cre/ERT2, DhhFlox/Flox (DhhECKO) mice and their control littermates were administered with tamoxifen at 8 weeks of age to induce Dhh KO. Their cardiac function, exercise tolerance, and the phenotype of their coronary vasculature were assessed one month later.

Results:
DhhECKO mice presented significantly reduced exercise tolerance, increased end diastolic pressure (EDP) and Tau, with no change in their ejection fraction consistent with diastolic dysfunction. At molecular and cellular level, impaired cardiac relaxation in DhhECKO mice was associated with a significantly decreased phospholamban phosphorylation on Thr17 and an alteration of sarcomeric shortening in ex-vivo. Besides, as expected, DhhECKO mice exhibited phenotypic changes in their coronary vasculature including a prominent pro-thrombotic phenotype leading to an impaired capillary perfusion and local hypoxia. Notably, antiaggregant therapies (aspirin and clopidogrel) prevented the occurrence of both diastolic dysfunction and exercise intolerance in DhhECKO mice demonstrating for the first time that thrombosis may promote diastolic dysfunction. Importantly, we confirmed the critical role of thrombosis in Leprdb/db mice which also displayed increased cardiac small vessel thrombosis in comparison to control mice. Alike DhhECKO mice, we found that antiaggregants decreased EDP and improved exercise tolerance in Leprdb/db mice.

Conclusion:
Altogether, these results demonstrate that small vessel thrombosis may participate in the pathophysiology of heart failure with preserved ejection fraction.
Abstract P2097: Ablation Of Fibroblast Human Antigen R (HuR) Mitigates Cardiac Fibrosis
Authors: Singh Sarojini , Patil Mallikarjun , Dubey Praveen K , Sultan Tousif , Umbarkar Prachi , zhang qinkun , Lal Hind , pogwizd Steven , Zhang Jianyi J , Krishnamurthy Prasanna
Published: October 2023

Background:
Cardiac fibrosis is a common pathology associated with various heart diseases and is attributed to the activation of resident fibroblasts. Limiting fibroblast-to-myofibroblast differentiation and proliferation could be a pragmatic approach to mitigate adverse cardiac outcomes. Recent studies have shown that RNA-binding proteins are critical in the post-transcriptional regulation of fibroblast-to-myofibroblast differentiation. Human antigen R (HuR), an RNA-binding protein, modulates post-transcriptional gene expression in various pathophysiology, including heart diseases. However, the direct role of cardiac myofibroblast HuR is largely unknown.

Methods and Results:
To investigate the role of myofibroblast-specific HuR in cardiac fibrosis, we generated a tamoxifen-inducible periostin-Cre-driven myofibroblast-specific HuR knockout (KO) mouse. Control and KO mice were subjected to transverse aortic constriction (TAC), and cardiac functions were assessed by echocardiography. Histological and morphometric analyses were used to evaluate cardiac fibrosis and remodeling eight weeks post-injury. Our results demonstrated that myofibroblast-specific deletion of HuR limited cardiac fibrosis and preserved cardiac functions in HuR knockout mice compared to the control group. Further, the knockdown of HuR in human cardiac fibroblasts suppressed myofibroblast differentiation after treatment with TGF-β1 (10 ng/ml), as observed by a decrease in cell migration and production of extracellular matrix-associated molecules. Interestingly, an
in vivo
BrdU labeling assay showed a reduction in myofibroblast proliferation in KO mice subjected to TAC compared to the control. Further investigation confirmed that HuR regulates cyclin D1 mRNA stability in TGF-β1-stimulated cardiac fibroblasts, and deletion of HuR restricts myofibroblast proliferation in a cyclin D1-dependent manner.

Conclusion:
Our findings indicate that HuR plays a central role in the post-transcriptional regulation of cardiac fibrosis and could be a potential therapeutic target for clinical applications.
Abstract P2119: Effect Of PCI On QTd And QT Interval Compared To Control/other Treatments For Myocardial Infarction
Authors: Vasavada Advait , Jain Manisha , Meenashi Sundaram Dakshin , Gudi Thulasi Ram , Mahfooz Kamran , Kotak Radhika , Singh Ganeev
Published: October 2023

Background:
QT dispersion measurement is a potential risk stratification tool but is a conflict in the literature on how PCI and other procedures affect it. We aimed to compare PCI with other procedures like Streptokinase, PCI plus thrombectomy, and coronary artery bypass graft (CABG) on QT interval.

Methods:
We conducted a systematic review and meta-analysis on the association between PCI and QTd through a literature search in three electronic databases, Science Direct, PubMed, and Google Scholar, for empirical studies published in English. Random effects model was used.

Results:
Eleven studies were found in total. We found significant differences in QTc between pre and post PCI and a significant reduction in QTc across all the studies (SMD 2.57, 95% CI 1.22 to 3.92; p<0.05). Five studies compared the efficacy of PCI and control (other procedures) in reducing QTd after 24 hours of treatment procedures. The mean change from baseline in QTd is more significant in the PCI group (post-PCI) compared to the control group, although there is no statistically significant difference between the two groups (SMD -0.30, 95% CI -1.25 to 0.65; I2 = 96%). A significant reduction in QTd corresponding to a statistically significant difference between QTd prior and post-PCI intervention for QTd at 2hrs, 24hrs, and 2-7 days, was found. The estimated overall effect measure reveals statistical significance (SMD 1.18, 95% CI 0.70 to 1.65; P < 0.05).

Conclusion:
QTd difference was significant post-PCI. Future studies on evaluating it as a predictor to various outcomes could illustrate it's benefit in clinical practise.
Abstract P2122: Coronary Heart Disease And Arthritis - An Analysis Of 2 Year Behavioral Risk Factor Surveillance System (BRFSS) Data
Authors: Sharma Akash , Anbu ananthan Velmurugan
Published: October 2023

Introduction:
Arthritis has increased systematic repercussions either by extra-articular manifestations or due to limited activities. Studies have fined an association between arthritis and heart disease. In this study, we try to find that arthritis is an independent association for myocardial infarction (MI) or coronary heart disease (CHD).

Methods:
In this study, we used the 2020 and 2021 Behavioral Risk Factor Surveillance System (BRFSS), a large, nationally representative, cross-sectional telephone survey. The data was divided into the participants having arthritis or no arthritis. Results were pooled and were represented with an odds ratio (OR) with a 95% CI interval. We used a logistic regression model to pool the results and adjusted for different variables. Two different models were constructed, and ANOVA was used to compare different models. The analysis was done by using R statistical software. Fisher t-test was used to compare between 2 groups. P-value < 0.05 was considered significant.

Results:
Pooled results of the BRFSS survey led to 835,452 participants included in the final analysis. Of the included participant, 267020 has arthritis, and 568432 does not. 38.7% were males, and 61.3% were females. In the arthritis group, 38.7% were males, and 61.3% were females. Also, 55.1% of individuals in the arthritis group are older than 65. Our analysis found that arthritis people have a higher prevalence of diabetes and stroke. We analyzed logistic regression after adjusting for sex, race, age, diabetes, stroke, and BMI. It was found that participants with arthritis have higher odds of MI or CHD ( OR = 1.055, 95% CI 1.154-1.157, p-value < 0.001) compared to non-arthritis people and when adjusted for sex, race, age it was 1.074, 95% CI 1.073-1.075, p-value<0.001).

Conclusion:
We find that arthritis is associated with an increased risk of MI or CHD independent of other risk factors. Hence, patients with arthritis need close monitoring for heart-related disease.
Abstract P2133: Preservation & Vascularization Of Cardiac Extracellular Matrix After Acute Myocardial Infarction
Authors: Niu Hong , Liu Zhongting , Guan Ya , Dang Yu , Guan Jianjun
Published: October 2023

Following myocardial infarction (MI), the upregulated matrix metalloproteinases (MMPs) especially MMP-2/9 lead to the degradation of cardiac extracellular matrix (ECM), leading to impaired cardiac function. Therefore, preservation of cardiac ECM by decreasing MMP-2/9 acitivity will increase cardiac function. Meanwhile, vascularization is critical for cardiac ECM as otherwise its structure and composition change over time. In this work, a non-toxic peptide CTTHWGFTLC (CTT) that specifically inhibits MMP-2/9, and a pro-angiogenic basic fibroblast growth factor (bFGF) were used to preserve and vascularize the cardiac ECM. A fast gelling, degradable, and reactive oxygen species (ROS)-scavenging hydrogel was developed to deliver CTT and bFGF to the infarcted hearts. We evaluated the efficacy of the delivery system in preserving and vascularizing cardiac ECM, and improving cardiac function. The combination of CTT and bFGF synergistically promoted tube formation of HUVECs compared to the treatment with CTT or bFGF (**p<0.01). Interestingly, both CTT and bFGF inhibited myofibroblast differentiation of cardiac fibroblasts. The combination of CTT and bFGF further significantly decreased the differentiation. After 28 days of implantation of the CTT/bFGF/Gel, the wall thickness was significantly increased compared to the CTT/Gel, bFGF/Gel, Gel only and MI. The released CTT and bFGF preserved cardiac ECM, decreased cardiac fibrosis, and stimulated angiogenesis in the infarcted area, leading to a significant increase of cardiac function.
Abstract P2137: Comparative Effectiveness And Safety Of Rivaroxaban Versus Warfarin In Valvular Atrial Fibrillation: A Systematic Review And Meta-Analysis
Authors: Affas Ziad Rafe H , Sebastian Sneha Annie , Rasool Banan , Padda Inderbir , Amen Shwan , Arnautovic Jelena , Johal Gurpreet
Published: October 2023

Introduction:
Patients with valvular atrial fibrillation (AF), which refers to moderate to severe mitral stenosis or mechanical prosthetic heart valves, have an increased risk of ischemic stroke and systemic embolism, which mandates the need for long-term anticoagulation. Still, there are no clear consensus guidelines on the indications of anticoagulation therapy in valvular AF. We aimed to compare the effectiveness of rivaroxaban, a common direct-acting oral anticoagulant (DOAC), to warfarin for preventing thromboembolism in valvular AF patients.

Methods:
We performed a systematic search of the following databases; PubMed, Cochrane Library, Google Scholar, and EMBASE from inception until February 06, 2023.

Results:
After screening 389 studies, 8 studies with 68,847 patients have been included in the final analysis. Our meta-analysis did not reveal a significant difference in the occurrence of all-cause mortality between patients who received rivaroxaban and those who received warfarin [RR, 0.97 (95% CI: 0.53-1.76]), p =0.91]. On analysis of the individual studies, rivaroxaban was non-inferior to warfarin with a lower risk of bleeding events [RR, 0. 80 (95% CI: 0.62-1.04), p =0.72], myocardial infarction [RR, 0.56 (95% CI: 0.13-2.47), p =0.44], and stroke/systemic embolism [RR, 0.54 (95% CI: 0. 11-2.55), p = 0.43]. But there was no statistically significant difference between the two groups.

Conclusions:
With a decreased risk for major adverse events, rivaroxaban appears to have a favorable safety profile, making them a promising alternative to warfarin in treating patients with valvular AF. However, more randomized clinical trials are imperative.
Abstract P2154: A Novel Allosteric Modulator Of The β
1
AR Identified By DNA-encoded Small Molecule Library Screening Demonstrates Unique Pharmacology And Function
Authors: Grogan Alyssa , Ahn Seungkirl , Israel David , Shaginian Alex , Chen Qiuxia , Liu Jian , Wilkey Max , Wang Jialu , Kahsai Alem , Lefkowitz Robert J , Rockman Howard A
Published: October 2023

While traditional β-blockers (i.e. competitive orthosteric antagonists of β-adrenergic receptors; βARs) are widely used as cardiovascular therapeutics, adverse effects such as fatigue and the nonselective inhibition of multiple receptor subtypes often limit maximal effectiveness. An emerging approach to enhance therapeutic targeting is to identify allosteric modulators that act cooperatively with orthosteric ligands. In contrast to orthosteric ligands which bind the endogenous ligand binding site, allosteric modulators bind to regions that are topographically distinct from the orthosteric pocket and can enhance (positive allosteric modulator; PAM) or reduce (negative allosteric modulator; NAM) the activities of orthosteric agonists/antagonists. Since allosteric regions exhibit greater sequence and structural diversity among receptor subtypes relative to the more highly conserved orthosteric pocket, allosteric modulators are more likely to be subtype specific and/or generate less adverse effects. We therefore embarked on a DNA-encoded small molecule library screen to identify novel allosteric modulators of the β
1
AR. Following multiple rounds of affinity selection using purified, functional, β
1
ARs reconstituted in lipid nanodiscs and HitGen’s OpenDEL® small molecule library containing more than 1 billion unique compounds, we identified Compound 11 (C11) as an allosteric modulator with unique pharmacological properties. Notably, C11 binds to the β
1
AR with micromolar affinity and enhances the binding affinity of orthosteric agonists and certain antagonists to the β
1
AR. In contrast to its positive cooperative effect on ligand binding, cell signaling assays showed C11 potently inhibits G protein and β-arrestin signaling downstream of the β
1
AR. Importantly, C11 showed high β
1
AR specificity with no effect on β
2
AR or AT
1
R signaling. These results suggest that C11 is a β
1
AR-specific PAM in terms of ligand binding but a NAM in terms of agonist efficacy, belonging to a largely under-characterized class of allosteric modulators termed PAM-antagonists. With an extremely unique pharmacological profile, C11 is a promising potential therapeutic and experiments evaluating its ability to modulate β
1
AR signaling
in vivo
are ongoing.
Abstract P2164: Expression Of Engineered Bacterial Sodium Channel Improves Cardiomyocyte Contractility
Authors: Wu Tianyu , Li Binjie , Koconis James , Bhattacharjee Abhishek , Ye Lei , Bursac Nenad
Published: October 2023

Introduction:
Our recent studies in non-human primates have demonstrated adeno-associated virus (AAV) delivery of prokaryotic sodium channel (BacNa
v
) can improve the contractile function of infarcted hearts. We hypothesized that BacNa
v
expression increases cardiomyocyte (CM) contractile function by indirectly augmenting Ca
2+
transient amplitude via increase in sarcoplasmic reticulum (SR) Ca
2+
stores.

Methods:
We developed an
in vitro
model of ischemia-reperfusion (I/R) injury in engineered heart tissues (cardiopatches) made from human iPSC-derived CMs (hiPSC-CMs). Prior to formation, tissues were transduced with lentivirus conferring a doxycycline (Dox)-inducible expression of BacNa
v
. Upon I/R injury, the tissues were treated with either vehicle or Dox for 48h followed by force testing and Ca
2+
imaging. The effect of BacNa
v
expression on Ca
2+
handling was additionally studied using neonatal rat ventricular myocytes (NRVMs).

Results:
The tissue injury from I/R was evident from increases in cleaved-caspase 3 area (0.25% vs 1.53%), ROS generation (1.2 fold), LDH release (4.1 fold), and percent dead cells (0.97% vs 4.67%). Immediately following the I/R injury, tissues showed decrease in contractile force (2.78mN vs 0.74mN) and conduction velocity (20.7cm/s vs 7.9cm/s). At 72hr post-injury, BacNa
v
-expressing tissues exhibited significantly higher contractile force (1.67mN vs 1.32mN) and Ca
2+
transient (1.8 fold) amplitudes compared to the vehicle control. Furthermore, in uninjured NRVM monolayers, BacNa
v
expression resulted in higher Ca
2+
transient amplitude (1.31 fold), as well as increased SR calcium stores (1.3 fold) and slower sodium/calcium exchanger (NCX) extrusion rate (1.03s
-1
vs 0.82s
-1
) in the presence of caffeine. Blocking NCX with 10M ORM-10962 eliminated the difference in Ca
2+
transient amplitude between BacNa
v
-expressing and control CMs.

Conclusion:
Our results suggest BacNa
v
expression augments CM contractility and Ca
2+
transient amplitude, at least in part through the suppression of Ca
2+
efflux mode of the NCX. In addition to its antiarrhythmic effects, BacNa
v
gene delivery may represent an effective therapeutic strategy to improve cardiac contractility in congestive heart failure.
Abstract P2174: Transcriptomic Profiling Of Immune Checkpoint Inhibitor Myocarditis Reveals Novel Therapeutic Targets
Authors: Qin Juan , Zhang Shaoyi , Munir Amir , Chen Yen-Chou , Zhang Kuan , Li Jiaqi , Salem Joe-Elie , Moslehi Javid
Published: October 2023

Introduction:
Immune checkpoint inhibitor (ICI) therapy has revolutionized the treatment of advanced cancers. However, the increased use of ICI has also resulted in a higher incidence of ICI-related cardiovascular side effects, including myocarditis, which has a high mortality rate of nearly 50%. Understanding the mechanisms underlying ICI-related cardiotoxicity is essential for identifying new therapeutic targets and improving patient survival.

Hypothesis:
We hypothesized that ICI-myocarditis has a unique transcriptomic profile that could be used to identify new drug targets.

Methods:
To test our hypothesis, we isolated RNA from our ICI-myocarditis mouse hearts and performed RNA-seq using the Illumina NovaSeq 6000. We also reanalyzed a human IC-myocarditis dataset downloaded from the Gene Expression Omnibus database.

Results:
Our results demonstrated that in both our animal models and patients, the upregulated pathways in ICI myocarditis heart tissues were enriched for regulation of T cell activation, leukocyte adhesion, and multiple cytokine signaling pathways. Conversely, downregulated pathways included those involved in cellular respiration, oxidative phosphorylation, and cardiac conduction. The most significantly upregulated genes were involved in innate and adaptive immune responses, including the CD8-dependent gene program and response to interferon-gamma of macrophages. By querying the Drug Gene Interaction Database, we identified several novel biologically plausible therapeutic targets. Correspondingly, a number of FDA-approved drugs were revealed, including monoclonal or chimeric antibodies such as Tocilizumab and Alemtuzumab, recombinant proteins like Abatacept and Anakinra, as well as small molecules such as Ruxolitinib and Imiquimod.

Conclusions:
Our study is the first to use the entire transcriptomic profile of ICI myocarditis in both preclinical models and patients for drug discovery. Our results demonstrate that ICI myocarditis has a distinct gene expression profile compared to healthy and other cardiac diseases. By querying a drug-gene interaction database, we identified several novel drug targets and possible treatments for ICI-related cardiotoxicity.
Abstract P2188: Covid-19 Plasma Exposure Causes Transcriptional, Morphological, And Functional Changes Within The Pulmonary Microvascular Endothelium
Authors: Passi Rainha , Cholewa-Waclaw Justyna , Wereski Ryan , Veizades Stefan , Bennett Matthew , Berkeley Brownwyn , Solomonidis Emmanouil G , Caporali Andrea , Li Ziwen , Beqqali Abdelaziz , Dewerchin Mieke , Mills Nicholas L , Brittan Mairi , Baker Andrew H
Published: October 2023

Introduction and Aims:
While primarily a pulmonary disease, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect multiple organ systems, including the vasculature. Thus far studies have successfully characterised the whole organ compartment, however, our understanding of the mechanisms associated with COVID-19 infection and its impact on pulmonary microvasculature (pMV) remains incomplete. In human pulmonary microvascular endothelial cells (HPMVEC) treated with plasma from patients hospitalised with COVID-19, we aimed to evaluate transcriptional, morphological and functional changes, and to provide a mechanism for the excess mortality in patients with COVID-19 and how it may inform therapeutic advancement.

Methods and Results:
Plasma acquired from hospitalised patients with COVID-19 was compared to plasma from patients hospitalised without COVID-19 but with other acute illnesses, such as COPD. Exposure to plasma from patients with COVID-19 caused a significant functional decline in HPMVEC, with a decrease in both cell viability on the WST-1 cell-proliferation assay
(n=75, p= 0.013)
and cell-to-cell barrier function measured by electric cell-substrate impedance sensing
(n=3, p = 0.033)
. High content imaging using the cell painting image-based assay showed a phenotypic change in nuclear
(n=4, p=0.019)
and nucleic acid
(n=4, p=0.022)
morphology, indicative of a deterioration in core biological processes including protein transcription and metabolic output. Comparative deep RNA-sequencing of HPMVECs treated with COVID-19 plasma
(n=5)
confirmed upregulation of genes, notably
IFIT5
and
SFMBT1
. These genes are known to negatively regulate transcription and respond to viral infection, respectively, further demonstrating the phenotypic and transcriptional decline in the pulmonary microvasculature in patients with COVID-19.

Conclusion and Impact:
Our findings suggest that core biological processes are disrupted in the lung microvascular endothelium during severe COVID-19 disease contributing to aggravated disease. From a translational perspective, this knowledge could provide insight into possible treatment opportunities and prognostic tools that may directly target the dysregulated endothelium.