tbuckley/cabot-search huggingface dataset:
Abstract Mo028: Persistence of Fetal Cardiac Troponin T Modulates Disease Severity in Anthracycline-Induced Cardiomyopathy
Authors: Melissa Lynn, Catherine Vasquez, JR Exequiel Pineda, Matthew Klass, Jil Tardiff
Journal: Circulation Research (2024)

Anthracyclines are a key component in the management of pediatric cancers long recognized to carry significant risk of dose-dependent cardiotoxicity. Despite advancements in clinical management, considerable variation in the incidence of cardiotoxicity persists across dosing regimens suggesting modifiers exist. Recently, changes in the splicing of TNNT2, the gene encoding cardiac troponin T (cTnT), were postulated to contribute to anthracycline cardiotoxicity, potentially providing a direct link to the myofilament. Previous studies in our lab have demonstrated that the fetal isoform, cTnT1, is a potent modifier of cardiac function contributing to disease heterogeneity in animal models of cardiomyopathies. Thus, we hypothesize that the persistent expression of cTnT1 predisposes a subset of the population to anthracycline cardiomyopathy. Using molecular dynamics simulations (MD) and isothermal titration calorimetry (ITC), we assessed a range of anthracyclines for their potential to bind the cardiac thin filament (CTF). MD calculated Glide scores showed direct binding to the troponin complex. ITC indicated that this binding occurs at an order of magnitude higher affinity in complexes containing cTnT1. Stopped-flow kinetics of cTnT1 CTFs exposed to Doxorubicin showed an additive reduction in calcium dissociation rates, reinforcing our observations of direct binding to the CTF. Longitudinal 2D echocardiography of Doxorubicin treated mice (3mg/kg/week) indicated that both male and female cTnT1 mice exhibit an additive, dose-dependent reduction in cardiac systolic function compared to non-transgenic (NT) littermates. Consistent with clinical data, female mice exhibited an earlier reduction in % fractional shortening than males as well as delayed recovery after treatment cessation. Transcriptional profiling of mice treated with Doxorubicin revealed a 2- to 7-fold additive increase in type I and type II interferon signaling in cTnT1 mice above that observed in treated NT littermates. These data suggest that cTnT1 may increase binding of anthracyclines at the myofilament, eliciting accelerated cardiac dysfunction, and represent a unique, targetable genetic risk factor involved in anthracycline cardiotoxicity.
Abstract Mo010: Evidence for cardiomyocyte dysfunction in cancer-induced cachexia in mice
Authors: Christopher Dostal, Benjamin Hackl, Romy Steiner, Simge Baydar, HENRY GONG, J Reiner, Peter Pokreisz, Elena Lilliu, Nina Pilat, Dietmar Abraham, Jonathan Kirk, seth hallstrom, Elisabeth Ehler, Latifa Bakari, Chiara Riganti, Alessandra Ghigo, Erwin Wagner, Bruno Podesser, Xaver Koenig, Attila Kiss
Journal: Circulation Research (2024)

Background: There is currently no therapy targeting cancer-related cardiomyopathy and treatment of heart failure in the oncological setting is nonspecific. Moreover, cancer is often assocaited with cachexia and the pathophysiology of cancer-cachexia induced cardiac (dys)functions are not fully known. Methods: Colon-26 adenocarcinoma (C26; n=30) or shIL-6 (C26 shIL-6; n=30) cells were inoculated subcutaneously into the flank of syngeneic adult male BALB/cmice, meanwhile control mice were injected with PBS (n=25). Twenty days after the cells injection, cardiac function was assessed using transthoracic echocardiography, ex vivo isolated working heart methods. In addition, intracellular Ca 2+ transient and force-calcium relationships were assessed in isolated single ventricular cardiomyocytes (CMs). Cardiac inflammation, metabolism and fibrosis were also assessed. Results: Despite that tumor size was comparable between the cancer groups, C26 group showed a loss of subcutaneous fat and skeletal muscle confirming a cachectic phenotype in association with an elevation of serum IL-6 levels. Tumor-bearing mice groups show a tendecy towards to both LV systolic and diastolic dysfunction. Sarcomere dysfunction, including significantly reduced maximum calcium-activated tension (Tmax) and increased calcium sensitivity (decreased EC 50 ) was found in skinned cardiomyocyte preparation from both tumor-bearing mice in compared to controls (p&lt;0.05, respectively). Intracellular Ca 2+ transient was exclusively increased in CM isolated from cachectic mice, suggesting the SERCA2 upregulation. Infiltration of macrophage or T-cells, nor interstital fibrosis were difference. β-myosin heavy chain expression is upregulated in a cell autonomous fashion in C26 mice. Comprehensive energetic and metabolims analysis showed shift to a profound glucose metabolsim and reduction in fatty acid oxidation in LV samples. This was futher proven in h9c2 cells were incubated with C26 or shIL6 cell culture medium. Discussion: Our results suggest that LV dysfunction in cancer mice is associated with sarcomere dysfunction while additional abnormal intracellular Ca 2+ handling is solely present in mice with cachectic phenotype. These functional alterations are independent from changes in myocardial fibrosis and inflammation but may rely on the cardiac metabolism alterations. These data provide new insights into how cancer and cancer-cachexia impacts the cardiac performance even prior to cancer therapy treatments.
Abstract Mo024: Integrated analysis of <i>ex vivo</i> biomechanical ventricular remodeling and imaging-based <i>in vivo</i> strain changes in a pre-clinical murine model of radiation-induced cardiotoxicity
Authors: Tanmay Mukherjee, Sarah Elliott, Taylor-Jade Higgins, Janaka Wansapura, Prasanna Alluri, Reza Avazmohammadi
Journal: Circulation Research (2024)

Introduction: Thoracic radiation therapy (RT) is commonly used for the treatment of many common malignancies, such as lung and breast cancer, but carries a high risk of radiation-induced cardiotoxicity (RIC). Existing diagnosis of RIC is challenged by subclinical ventricular dysfunction, not captured by global indices of cardiac function. Understanding RIC-driven biomechanical remodeling of the myocardium will provide novel insights into developing high-fidelity imaging approaches for early detection of RIC. Methods: A pre-clinical model of RIC was developed by administering whole heart irradiation under image guidance in mice (8 Gy x 5) over five consecutive days. A longitudinal study was carried out to investigate the biomechanical response of the left ventricle (LV). Cardiac magnetic resonance imaging was performed to estimate end-systolic strains. Mechanical testing was performed on the harvested LV free wall (LVFW) specimens to measure passive stiffness, calculated as the tangent to the ensemble stress-strain curve at 30% strain. Results: A significant increase in passive LVFW stiffness was observed at 3M post-RT (Figs. 1A and B). Significant declines in both global circumferential strain (GCS) and global radial strain (GRS) at 3M post-RT, compared to respective measurements at pre-RT, were observed (Figs. 1C and D). Suppressed contractile strains suggested biomechanical remodeling of the LV, including impaired contractility and passive stiffening of the LVFW, consistent with ex-vivo measurements. Conclusion: We have established a direct correlation between ex-vivo mechanical testing (elevated stiffness) and reduced contractile strains in in-vivo analysis in a mouse model of RIC. Such integrated analysis will pave the way towards developing highly sensitive imaging approaches that non-invasively recapitulate the ventricular remodeling events associated with RIC, thereby enabling early detection of RIC in patients receiving thoracic RT.
Abstract Or110: Inflammation-induced endothelial cell activation and angiogenic sprouting are downmodulated by ubiquitin-specific peptidase 20
Authors: Bipradas Roy, Jiao-Hui Wu, Neil Freedman, Sudha Shenoy
Journal: Circulation Research (2024)

The deubiquitinase ubiquitin-specific peptidase 20 (USP20) reverses lysine-63 ubiquitination of the signaling adaptor TRAF6 and suppresses nuclear-factor-κB (NFκB) activation induced by proatherogenic stimuli in vascular smooth muscle cells (SMCs). Dephosphorylation of USP20 at Ser 334 augments USP20/TRAF6 binding and USP20-mediated TRAF6 deubiquitination, consequently decreasing NFκB signaling. SMC USP20 activity also attenuates atherosclerosis in Ldlr -/- mice. NFκB is a key mediator of vascular endothelial cell (EC) activation and inflammation-driven angiogenesis, which promotes growth and rupture of atherosclerotic plaques. We tested the hypothesis that USP20 attenuates EC NFκB signaling and decreases angiogenesis, with both in vitro and ex vivo models to study the role of USP20 in EC activation and ensuing angiogenesis. We analyzed experimental data by one-way ANOVA followed by Holm-Šídák's multiple comparisons test. Cytokine-induced NFκB activity was elevated in primary ECs isolated from Usp20 -/- mice as compared with ECs from congenic wild type (WT) mice (N=3, p&lt;0.001). Assessed by scratch-wound healing and spheroid assays, respectively, migration and angiogenesis of mouse coronary endothelial cells (MCECs) transduced with recombinant adenoviruses was (a) increased by inactive USP20 or phospho-mimetic USP20(S334D) (migration, N=4, P&lt;0.05; angiogenesis, N=6, P&lt;0.01), and (b) decreased by transduction with WT USP20 or phospho-resistant USP20(S334A) (migration, N=4, P&lt; 0.05; angiogenesis, N=6, P&lt;0.01). Additionally, chemical inhibition of NFκB activation with TPCA-1 (which inhibits the upstream kinase IKK-2) attenuated MCEC migration (N=4, P&lt;0.0001) and angiogenesis (N=6, P&lt;0.005), as compared with untreated cells. Angiogenesis assessed by aortic ring sprouting was increased in Usp20 -/- compared with WT specimens (males, N=3, P&lt;0.0001; females, N=2, P&lt;0.0001), and it was also suppressed by TPCA-1 (males, N=2, WT; N=3 Usp20 -/- , P&lt;0.0001; females, N=2 WT; N=3, Usp20 -/- P&lt;0.0005). Angiogenesis was enhanced in aortic rings from USP20(S334D) CRISPR/Cas9 gene-edited mice (males, N=3, P&lt;0.01; females, N=3 WT &amp; N=4, USP20(S334D) P&lt;0.0001), but reduced in aortic rings from USP20(S334A) mice (males, N=3, P&lt;0.05; females, N=3 WT &amp; N=5 USP20(S334A) P&lt;0.0001). We conclude that preserving EC USP20 activity by preventing phosphorylation of USP20 on Ser 334 diminishes endothelial activation and angiogenic sprouting, which can decrease atherosclerosis.
Abstract Mo011: Selective silencing of p38δ is cardioprotective in female mice during doxorubicin chemotherapy
Authors: Katy Trampel, Daniel O Reilly, Katherine Gross, Sharon Ann George, Anastasia Khvorova, Igor Efimov, Tatiana Efimova
Journal: Circulation Research (2024)

Introduction: Dose-dependent cardiotoxicity limits the efficacy of chemotherapeutic agent doxorubicin (DOX). p38δ is one of four p38 mitogen-activated protein kinase isoforms that regulate DOX-induced cardiotoxicity (DIC). p38δ genetic deletion protects female mice from DIC. In the absence of selective pharmacologic inhibitors of p38δ, docosanoic acid (DCA) conjugate-mediated delivery of chemically engineered small interfering RNA (siRNA) provides a novel avenue to achieve selective, efficient, durable, and nontoxic in vivo p38δ silencing in the heart. Hypothesis: The selective silencing of p38δ is cardioprotective from DIC in female mice. Methods: Following the screening of a panel of p38δ-selective siRNA sequences, the lead siRNA si-p38δ-1, with the highest silencing efficacy and potency in vitro, was identified. 15-week-old female mice were subcutaneously injected with 20 mg/kg of DCA-conjugated chemically stabilized si-p38δ-1 (n = 3) or the non-targeting control (NTC) siRNA (n = 3) twice 10 hours apart. p38δ silencing in mouse hearts was measured 14 days later by assessing mRNA and protein expression. To evaluate the effect of p38δ silencing after acute DOX treatment, the mice were administered si-p38δ-1 (n = 5) or NTC (n = 5), followed by DOX treatment (30 mg/kg) six days later. The study concluded 11 days after DOX treatment. Morbidity was assessed by assigning health scores daily. Electrocardiography, echocardiography, and optical mapping were performed to evaluate cardiac function. Results: si-p38δ-1 led to 80% silencing of p38δ in mouse hearts 14 days after administration, without any cardiotoxic effects. si-p38δ-1-treated female mice exhibited diminished DOX-induced morbidity (p = 0.003) and were protected from developing calcium alternans (CAs) 11 days post-DOX treatment, compared to NTC-treated counterparts. Thus, DOX-induced CAs, indicative of calcium mishandling, were observed in 75% (3/4) NTC-treated mice and 0% (0/5) si-p38δ-1-treated mice. Conclusion: Efficient and well-tolerated in vivo p38δ silencing by si-p38δ-1 in mouse hearts mitigated DOX-induced morbidity and calcium mishandling in female mice, highlighting the therapeutic potential of p38δ silencing for alleviating DIC in female cancer patients.
Abstract Or112: Cardiac Macrophage are Key Immune Drivers of Cardiometabolic HFpEF
Authors: Mehak Goel, Ameen Ismahil, RAVI SONKAR, Shyam Bansal, Yujie Zhu, wei liu, Tariq Hamid, Gregg Rokosh, Michael Katsnelson, Sumanth Prabhu
Journal: Circulation Research (2024)

Heart failure with preserved ejection fraction (HFpEF) can develop with obesity, hyperinsulinemia, and glucose intolerance or type 2 diabetes, a phenogroup designated cardiometabolic HFpEF. While inflammation considered an important underlying mechanism, the role of innate immunity is poorly define. We investigated the role of macrophages in pathogenesis of cardiometabolic HFpEF. C57BL/6 mice were fed either high-fat diet (HFD, 45% kcal fat, 35% carbohydrate, 20% protein, 4.73 kcal/g) or control diet (CD, 10% kcal fat, 70% carbohydrate, 20% protein, 3.85 kcal/g) for 24-28 weeks. HFD mice exhibited significantly increased body weight (BW) at equivalent calorie consumption, increased white adipose tissue (WAT) mass, glucose intolerance, and hyperinsulinemia. HFD mice also exhibited HFpEF, evidenced by increased relative wall thickness (RWT), E/e’ ratio, LA area, LVEDP, and lung weight and decreased exercise tolerance with preserved EF. CD64 + MHCII + LyVE1 + CCR2 – resident and CD64 + MHCII + CCR2 + infiltrating macrophages expanded significantly in both cardiac and visceral fat tissue. To evaluate the role of macrophages in HFpEF, we used Macrophage Ablation Fas-Induced Apoptosis (MaFia) mice that allow for conditional depletion of mononuclear phagocytes with the Fas ligand dimerizer AP20187. AP20187 treatment after 24 weeks of HFD feeding in MaFia mice depleted macrophages and normalized BW, and reversed cardiac hypertrophy (decreased RWT, histological myocyte cross-sectional area [CSA]), and cardiac dysfunction (improved E/e’ ratio and global longitudinal strain [GLS]), as compared to vehicle-treated HFD-induced HFpEF MaFia mice. To establish sufficiency of cardiac macrophages, we FACS-sorted CD45 + CD64 + F4/80 + cardiac macrophages from HFD and CD mice, and adoptively transferred (10K cells/mouse) by intramyocardial injection into naïve recipient mice, with evaluation 4 w later. Mice with HFD-heart cardiac macrophage transfer evidenced significant increases in left atrial area (P=0.008, E/e’ ratio (P=0.016), cardiomyocyte CSA (P=0.015) and cardiac fibrosis (P&lt;0.05), and reduced |GLS|, as compared to recipient mice with CD-heart cardiac macrophage transfer. There were no differences in body weight between the two groups. We conclude : cardiac macrophage expansion is central to the pathogenesis of cardiometabolic HFpEF, and are both necessary and sufficient for the cardiac phenotype. These results raise the potential for macrophage-targeted interventions to mitigate HFpEF.
Abstract Mo134: Restoring NaV1.5 Mutant Functionality in Arrhythmia with ManNAc Supplementation
Authors: Adriana Tarantino, Dario Melgari, Ivana Lavota, Paola Rota, Anthony Frosio, Ilaria Rivolta, Carlo Pappone, Luigi Anastasia
Journal: Circulation Research (2024)

The SCN5A gene encodes the human cardiac sodium channel NaV1.5, essential for cardiac excitability and action potential propagation. Mutations in SCN5A are linked to various cardiac disorders, including Brugada Syndrome (BrS), typically leading to channel loss-of-function. Understanding alterations in NaV1.5 expression and sodium current density is vital for comprehending arrhythmogenesis and formulating therapeutic strategies. Post-translational modifications, especially sialylation, significantly impact channel functionality. We previously demonstrated that BrS patients show decreased protein sialylation, correlating with reduced sodium channel activity. This study aimed to investigate sialic acid's role in regulating NaV1.5 activity, testing if sialylation induction via mannosamine (ManNAc) supplementation could restore channel activity in-vitro. Preliminary tests with exogenous sialidases and ManNAc supplementation affirmed our hypothesis. We examined ManNAc's effect on NaV1.5 mutants common in BrS, which typically exhibit partial functional loss. We overexpressed mutations p.A344S, p.K1479A, and p.G1406R in HEK293A cells and measured sodium currents before and after ManNAc supplementation to stimulate sialic acid synthesis. ManNAc effectively restored sodium currents in mutants with intracellular and extracellular loop mutations. However, the p.1406G&gt;A mutant, affecting the pore structure, showed no improvement, suggesting that sialic acid mainly influences channel membrane trafficking rather than direct glycosylation. This underscores the complexity of sialic acid's role and points to trafficking pathways as potential therapeutic targets. Notably, the treatment neither increased nor decreased sodium currents in wild-type NaV1.5 channels or in the CaV3.2 calcium channel, underscoring its specificity. In summary, our findings demonstrate that ManNAc supplementation can selectively restore the function of certain NaV1.5 mutants without affecting wild-type channels, highlighting the potential of targeting sialylation pathways for SCN5A-related arrhythmia treatments. Future research should aim to unravel these mechanisms further, providing insights into novel treatments for SCN5A-related arrhythmias.
Abstract Or126: Targeting ER stress can attenuate arrhythmia in catecholaminergic polymorphic ventricular tachycardia
Authors: Roland Veress, Radmila Terentyeva, Sage Quiggle, Fruzsina Perger, Andriy Belevych, Dmitry Terentyev, Shanna Hamilton
Journal: Circulation Research (2024)

Gain-of-function mutations of the sarcoplasmic reticulum (SR) Ca 2+ release channel, the ryanodine receptor (RyR2), are linked to the inherited arrhythmia syndrome catecholaminergic polymorphic ventricular tachycardia (CPVT). Increasing evidence suggests that RyR2 gain-of-function not only disturbs intracellular Ca 2+ homeostasis but drives remodeling of cell signaling and ultrastructure that markedly contributes to the arrhythmogenic phenotype. It is well established that disturbed SR Ca 2+ homeostasis can activate the endoplasmic reticulum (ER) stress response, yet whether RyR2 gain-of-function in CPVT drives ER stress is yet to be explored. The goal of our study was to determine the contribution of ER stress evoked by RyR2 gain-of-function to cardiac arrhythmogenesis. To test this, we created a new rat model of CPVT induced by RyR2-S2222L (+/-) mutation. Simultaneous whole cell patch clamp and Ca 2+ imaging demonstrated that under β-adrenergic stimulation, CPVT ventricular myocytes (VMs) exhibit a high propensity to spontaneous Ca 2+ waves (SCWs) and delayed afterdepolarizations. Importantly, CPVT VMs showed increased XBP1 splicing as a marker of ER stress, as well as increased intra-SR redox stress measured using biosensor ER_roGFPiE. Assessment of ER stress proteins that contribute to SR redox status revealed upregulation of H 2 0 2 -producer enzyme ERO1α, with no compensatory change in expression of H 2 O 2 -degrader Peroxiredoxin-4 (PRDX4). Adenoviral overexpression of PRDX4 in CPVT VMs not only normalized SR redox status but attenuated Ca 2+ mishandling, reducing RyR2 activity and the incidence of proarrhythmic spontaneous Ca 2+ waves. Of note, immunofluorescence and biochemical studies suggest a direct interaction between RyR2 and PRDX4. To test whether targeting ER stress was protective at the whole heart level, we delivered AAV9-αMHC-PRDX4 to CPVT rats and performed ex vivo optical mapping. While CPVT hearts exhibited triggered activity and increased incidence of VT, sustained VT was prevented in PRDX4-injected hearts. Collectively, these data strongly suggest that ER stress contributes to the arrhythmogenic phenotype of CPVT. Targeting ER stress protein PRDX4 has promising therapeutic potential to normalize SR homeostasis, stabilize RyR2 activity and attenuate Ca 2+ -dependent arrhythmogenesis.
Abstract Mo127: Nitrate Supplementation Plus Voluntary Activity in C57Bl/6 Mice Improves Fitness and Impairs Cardiac Calcium Handling In a Sex Specific Fashion
Authors: Elise Bisset, Shubham Banga, Susan Howlett
Journal: Circulation Research (2024)

Nitrate supplements are commonly combined with aerobic exercise to potentially improve performance and cardiac function. Whether this combination benefits cardiac function at the organ and cellular levels is unclear. We will determine if nitrates affect fitness or cardiac function in both sexes. C57Bl/6 mice (9-mos) were given 1mM sodium nitrate (drinking water) and/or access to a running wheel for 3 mos. Cardiac function (echocardiography), blood pressure (tail cuff) and fitness (treadmill) were measured. Calcium transients (Fura-2) and contractions (2Hz) were measured in ventricular myocytes and calcium handling proteins were measured by qPCR. In both sexes, nitrates did not change blood pressure or voluntary wheel running although females ran more than males (3.7±0.3km vs 2.2±0.3km, p=0.002). In exercised female mice, nitrates increased fitness from baseline while control did not (top speed at exhaustion: 24.2±1.4 to 28.0±1.5 cm/s, p=0.07 vs 23.3±1.0 to 30.7±2.0 cm/s, p=0.002) but nitrate supplemented males showed no fitness benefit. However, while exercise improved cardiac function and contractility compared to sedentary mice, nitrates plus exercise impaired cardiac function in a sex-specific manner. Nitrate-treated males who exercised had lower E/A ratios (1.8±0.3 vs 1.3±0.1, p=0.01) and worse diastolic function than control exercised males. By contrast, nitrate-treated female mice who exercised had smaller global longitudinal strain (-19.5±1.5 vs -11.8±3.0%, p=0.01) than controls, indicative of worse systolic function. Corresponding changes were seen at the cellular level. Exercised males given nitrates had slower a calcium transient decay than controls (44.8±4 vs 73.8±6 ms, p=0.01), while females given nitrates had slower velocity to peak calcium (0.031±0.004 vs 0.018±0.003 µm/ms, p=0.005) and smaller cellular contractions (2.9±0.5 µm vs 1.4±0.5 µm: p=0.03). Cardiac calcium handling proteins were also modified in females. Exercise plus nitrates caused a decrease in SERCA2a and ryanodine receptor 2 expression (mRNA) compared to the control exercise group. Studies in males are ongoing. Exercise plus nitrates increased fitness levels in only females and reduced cardiac function in a sex specific way when compared to exercise alone. This suggests a potential balance between benefits to fitness and potential cardiac complications that could affect athletes taking nitrate supplementation.