tbuckley/cabot-search huggingface dataset:
Abstract 14304: The Role of Foxc1 During the Differentiation of Embryonic Stem Cells Into Functional Cardiomyocytes
Authors: Erin Lambers, Baron Arnone, Anees Fatima, John A Wasserstrom, Gangjian Qin, Tsutomu Kume
Journal: Circulation (2015)

Background: Embryonic Stem Cells (ESCs) hold great potential for regeneration of damaged myocardium, however the molecular circuitry that guides ESC differentiation into cardiac lineages remains poorly understood. This is exemplified by the elusive role of the developmental transcription factor, Foxc1, during cardiac development. When one human FoxC1 allele is mutated it causes Axenfeld-Rieger syndrome characterized by ocular defects and often heart defects. Foxc1 homozygous null mice are either embryonic lethal or die soon after birth with the majority of these mice containing severe heart malformations. The only known Foxc1 target during heart development is Tbx1, a transcription factor necessary for the proper alignment of the outflow tract. Because Foxc1 null mice contain heart defects that are far more severe than Tbx1 null mice, it is likely that foxc1 has additional regulatory roles in heart development. It is unknown in which specific cell types of the heart Foxc1 functions. Hypothesis: Foxc1 is critical for ESC differentiation into functional cardiomyocytes through the regulation of a downstream regulatory transcription network. Methods and Results: Using a murine Nkx2.5-GFP reporter ESC line, we show that Foxc1 knockdown (KD) reduces the number of Nkx2.5+ cells upon differentiation. Foxc1 KD also reduces a panel of cardiomyocyte marker transcripts as well as inhibits the beating of embryoid bodies (EBs). On the other hand, using an inducible Foxc1 overexpression (OE) ESC line, we show that Foxc1 OE increases a panel of cardiomyocyte transcripts and enhances the number beating of EBs. Additionally, Foxc1 OE beating EBs have an enhanced spontaneous beat rate and possess functional electrophysiological properties, beating in synchrony with surrounding cardiomyocytes upon electrical stimulation. RNA-sequencing results identify over 3,000 differentially regulated transcripts after Foxc1 OE during cardiomyogenesis. Conclusion: Both molecular and functional analyses reveal a positive correlation between Foxc1 expression level and cardiomyogenesis. Currently chromatin-immunoprecipitation sequencing is being performed to determine the direct downstream regulatory network of Foxc1 during cardiomyogenesis.
Abstract 14341: A Depressed Cardiac Output in Patients With Advanced Heart Failure is Not Accompanied by Increased Plasma Lactate Levels in the Majority of Patients: Is it Time for a New Definition of Heart Failure?
Authors: Luigi Adamo, Michael Nassif, Shane Larue, Douglas L Mann
Journal: Circulation (2015)

Introduction: Heart failure (HF) has been defined as a condition in which the heart is unable to deliver sufficient oxygen to match the needs of the metabolizing tissues. This definition, which was based on observations in patients with terminal HF, has never been validated. Moreover, the application of this definition led to the use of inotropes , and discouraged the use of beta-blockers, delaying the development of appropriate HF therapies. Methods: To determine whether the heart was unable to meet the metabolic demands of the body, we retrospectively analyzed Arterio-Venous oxygen difference (AV O2) and plasma lactate levels in NYHA class IV heart failure patients that subsequently received a Left Ventricular Assist Device (LVAD). Results: We identified 359 patients with a right heart catheterization (RHC) performed prior to LVAD implantation. Plasma lactate was available for 96 patients. RHC showed that 93% of the patients had an AV O2 difference above normal (&gt; 5 ml/100 ml). Among patients with measured lactate levels the prevalence of elevated lactate (&gt; 2.1 mmol/L) was only 25% (95% CI 16.7-34.9). AV O2 was widened in all patients with elevated lactate, but plasma lactate did not correlate with AV O2 (R=0.02) and only 27% of patients with increased AV O2 had elevated plasma lactate ( Figure ). Patients with widened AV O2 and elevated lactate were sicker than patients with widened AV O2 and normal lactate, as shown by a higher prevalence of low INTERMACS class, elevated INR and reduced serum albumin. However, there was no obvious hemodynamic difference between the two groups. Conclusions: Approximately 75% of the patients in this NYHA class IV HF sample with a depressed cardiac output had normal lactate levels, suggesting that cardiac output was sufficient to meet the metabolic demands of the body. Given that approximately 4% of HF patients are NYHA class IV, these findings suggest that the classic definition of heart failure may be valid in only 1% of the total heart failure population.
Abstract 14261: Molecular Basis of the Protective Effect of β3-Adrenergic Receptor Deficiency on Myocardial Aging: Reversal of Aging-Induced Contrast Changes of Cardiac SERCA 2a and Inducible Nitric Oxide Synthase
Authors: Heng-Jie Cheng, Peng Zhou, Tiankai Li, Xiaowei Zhang, Satoshi Masutani, Dalane Kitzman, William Little, Che Ping Cheng
Journal: Circulation (2015)

Background: We have shown previously that aging-induced cardiac dysfunction and β-adrenergic desensitization were prevented in β 3 -adrenergic receptor (AR) knockout (β 3 KO) aged mice. However, the molecular mechanism is unclear. We hypothesize that reversal of aging-induced alterations of cardiac SR Ca 2+ -ATPase (SERCA2a) and inducible nitric oxide synthase (iNOS) by β 3 KO may play a key role for the protective effect. Methods: We compared protein levels of β 1 - and β 3 -AR, SERCA2a and iNOS, myocyte contractile, [Ca 2+ ] i transient ([Ca 2+ ] iT ) and Ca current (I Ca,L ) responses to isoproterenol (ISO, 10 -8 M) in LV myocytes obtained from 2 young (Y) (~6 m) and 2 aged (A) (~28 m) groups (6/group) of wild-type (WT) and β 3 KO mice, respectively. Results: Compared with YWT, AWT myocytes had significantly decreased protein levels of SERCA2a (AWT: 0.23 vs YWT: 0.64), and β 1 -AR (0.33 vs 0.58), but increased iNOS (0.50 vs 0.23) and β 3 -AR (0.34 vs 0.15) with reduced basal cell contraction (dL/dt max ) (84.5 vs 126.4 μm/s), relaxation (dR/dt max ) (66.9 vs 101.8 μm/s), [Ca 2+ ] iT (0.18 vs 0.24), and I Ca,L (4.4 vs 7.7 pA/pF). These changes were accompanied by diminished ISO-stimulated inotropic response. In AWT myocytes, ISO caused significantly less increases in dL/dt max (AWT: 33% vs YWT: 80%), dR/dt max (24% vs 62%), [Ca 2+ ] iT (16% vs 37%) and I Ca,L (15% vs 33%). Versus YWT, Yβ 3 KO did not alter basal myocyte contraction and relaxation and response to ISO stimulation, but had significantly increased protein levels of SERCA2a (Yβ 3 KO: 1.40 vs YWT: 0.62) and reduced iNOS (0.18 vs 0.26) with unchanged β 1 -AR (0.65 vs 0.62). Aβ 3 KO mice had similar alterations. Importantly, in contrast to AWT, in Aβ 3 KO myocytes, the increased SERCA2a (1.2) and reduced iNOS (0.16) correlated with normal basal cell contraction and relaxation with preserved ISO-stimulated inotropic response. ISO caused similar increases in dL/dt max (Aβ 3 KO: 80% vs Yβ 3 KO: 83%), dR/dt max (68% vs 61%), [Ca 2+ ] iT (30% vs 32%) and I Ca,L (29% vs 31%). Conclusions: β 3 KO prevents aging-caused downregulation of cardiac β 1 -ARs and reverses increased iNOS and decreased SERCA2a, leading to the preservation of myocyte function, [Ca 2+ ] iT , I Ca,L and β-adrenergic reserve in aged hearts. Thus, β 3 -AR may provide a new target for cardiac aging.
Abstract 14355: Sinus Rhythm Prior to Catheter Ablation Positively Impacts Ablation Outcome in Non-Paroxysmal Atrial Fibrillation Patients
Authors: Sanghamitra Mohanty, Prasant Mohanty, Chintan Trivedi, Carola Gianni, Mahmut F Gunes, Yalcin Gokoglan, Rong Bai, John David Burkhardt, Javier Sanchez, Patrick Hranitzky, G. J Gallinghouse, Amin Al-Ahmad, Rodney Horton, Luigi Di Biase, Andrea Natale
Journal: Circulation (2015)

Background: Catheter ablation of non-paroxysmal atrial fibrillation (NPAF) is associated with longer procedure times and lower long-term success rates than that of paroxysmal AF. We tested the hypothesis that NPAF patients entering the EP laboratory (lab) with sinus rhythm (SR) have shorter procedure time and better ablation-outcome than those with AF as the entry-rhythm. Methods: Total of 804 consecutive NPAF patients undergoing radiofrequency catheter ablation at our center were included in this prospective analysis. Based on the presenting rhythm in the EP lab, patients were classified into two groups; patients on SR (group 1, n=236, age 63±10 years, male 71%, LVEF 55.2±8.4, LA size 4.5±0.9 cm), patients in AF (group 2, n=568, age 64±10 years, male 69%, LVEF 54.4±11.4, LA size 4.6±0.6 cm). All patients were followed up for 38±6 months for arrhythmia recurrence by event recorder, ECG and Holter monitoring. Results: The baseline characteristics were not different between the groups. When comparing the procedural parameters between the groups, patients presenting with SR required significantly shorter radiofrequency time (64.1±30.7 min vs. 82.3±29.4 min in AF group, p&lt;0.0001) and procedure times (143.9±91.2 min vs. 162.3±62.2 min in AF group, p=0.019). At the end of follow-up, significantly higher recurrence rate was noted in those presenting with AF compared to patients on SR at the procedure; 264 of 568 (47%) vs. 80 of 236 (34%) respectively, log-rank p=0.002 (unadjusted hazard ratio 1.55 [1.17 - 2.05]) (figure). After adjusting for AF type, age, gender, LA size, and LVEF in multivariable Cox model, patients presenting with AF at procedure were twice more likely to fail compared to those on SR (hazard ratio 1.91 (95% CI 1.19 to 4.15), p=0.001). Conclusion: Sinus rhythm prior to catheter ablation for non-paroxysmal AF decreases the duration of ablation and increases the long-term efficacy of the procedure. Figure: Kaplan-Meier curve showing recurrence by study groups
Abstract 13277: A Unique Network Involving Cxcr4 and Cxcr7 Coordinates Cardiac Lineage Specification and Mobilization of Induced Pluripotent Stem Cells
Authors: Delaine K Ceholski, Irene C Tumbull, Andrew A Jarrah, Changwon Kho, Ahyoung Lee, Lahouaria Hadri, Kevin D Costa, Roger J Hajjar, Sima T Tarzami
Journal: Circulation (2016)

Introduction: An adult heart has an intrinsically limited capability to regenerate damaged myocardium. Human embryonic and induced pluripotent stem cell (hESC/hiPSC)-based therapies offer a unique strategy for developing cell replacement treatments for numerous disorders including cardiac diseases. Hypothesis: The present study identifies a unique signaling network, SDF-1/CXCR4/CXCR7, that regulates cardiac lineage differentiation and migration in human induced pluripotent stem cells (hiPSCs). The fact that SDF-1 binds to CXCR4 and CXCR7 raises a concern how to distinguish the potential contribution of the SDF-1/CXCR7 pathway from SDF-1/CXCR4 pathway in all the processes that were previously attributed to SDF-1/CXCR4. Therefore, we set these studies to disseminate the role of the SDF-1/CXCR4/CXCR7 network in cardiogenic lineage differentiation and migration of hiPSCs with the premise that their improved recruitment could translate into therapeutic benefits. Methods: Using lentiviral vectors to ablate CXCR4 and/or CXCR7 expression, hiPSC-derived cardiomyocytes (hiPSC-CMs) were tested for phenotypic and functional properties due to gene knockdown. Results: Gene expression confirmed cardiomyocyte phenotype of differentiated hiPSCs, although reduction of CXCR4 and CXCR7 expression resulted in delayed cardiac phenotype. Only knockdown of CXCR4 reduced the spontaneous beating of hiPSC-CMs. Knockdown of CXCR4 and CXCR7 differentially altered calcium transients and β -adrenergic response in hiPSC-CMs. In engineered cardiac tissues, depletion of CXCR4 or CXCR7 had opposing effects on developed force. The transendothelial migration response to SDF-1 was suppressed by knockdown of either CXCR4 or CXCR7. In contrast, in a trans-well chemotaxis assay, only depletion of CXCR4 reduced hiPSC migration in response to SDF-1. Conclusions: Both CXCR4 and CXCR7 have distinct roles in the SDF-1/CXCR4/CXCR7 axis as network coordinators of cardiogenic induction and mobilization of hiPSCs. We contend that gaining further insight into the molecular nuances of this phenomenon will provide new insights for optimization of the cardiac repair potential of cell-based therapies.
Abstract 19043: Novel Bioactive Peptide Amphiphiles Nanofibers for Enhancement of Human Cd34+ Cell Mediated Ischemic Tissue Repair
Authors: Yang Yu, Eduard Sleep, Samuel I Stupp, Gang J Qin
Journal: Circulation (2013)

Background: CD34+ cells have shown unprecedented promise for ischemic tissue repair in recent clinical trials; however, their recruitment, retention, and survival in the injured tissue remain one of the major barriers to the success of this novel therapeutic strategy. Methods and Results: In this study, we have developed a self-assembling bioactive peptide amphiphile (PA) nanofiber that displays the integrin-recognized cell adhesion epitope RGDS and then tested this novel scaffold material for therapeutic delivery, retention, and functional support of human CD34+ cells in a mouse model of critical hind-limb ischemia (CLI). In culture, PA nanofibers, but not non-bioactive nanostructures or nanostructures with scrambled DGRS epitope, significantly enhanced the adhesion and survival of human CD34+ cells under a number of cellular stresses. In CLI nude mice, intramuscular injection of human CD34+ cells contained in the RGDS nanostructures led to a significantly better blood perfusion, motor ability, limb salvage, and treadmill endurance when compared with those of CD34+ cells contained in DGRS nanostructures, cells alone or RGDS alone. Histology analyses revealed a higher viability and retention of CD34+ cells in the limb tissue of the RGDS nanostructures/CD34+ cells group than in the RGDS nanostructures alone or cells alone group. In consistent with the improved functional recovery, the density of capillaries in the ischemic limb of RGDS nanostructures/CD34+ cells group was significantly greater than in other groups. Conclusions: Our data demonstrate that integrin-specific binding epitope RGDS nanostructure enhances viability, adhesion, and angiogenic capability of human CD34+ cells. This pre-clinical study provides a rationale for further investigation of combining RGDS PAs with human CD34+ cells to enhance the effectiveness of cell therapy for ischemic limb disease.
Abstract 19010: Exercise but Not Pacing Affects Coronary-Cardiac Interaction via Reflected Waves From the Aorta
Authors: M. Cristina Rolandi, Tim Lockie, Bart-Jan Verhoeff, Divaka Perera, Kalpa de Silva, Simon Redwood, Mike Marber, Jan J Piek, Jos A Spaan, Maria Siebes
Journal: Circulation (2013)

Background: Not only the interaction with cardiac mechanics, but also the systemic circulation determines coronary hemodynamic waveforms. Coronary wave intensity can distinguish between forward (FW) waves entering from the aorta and backward (BW) waves originating from the microcirculation. The aim of this study was to assess contributions of the systemic circulation to cardiac-coronary interaction by comparing exercise, having a profound influence on the systemic circulation, with right atrial pacing where the systemic circulation is minimally affected. Methods: During cardiac catheterization we recorded aortic pressure (Pa), distal coronary pressure (Pd) and flow velocity (U) in diseased coronary arteries. In 10 subjects heart rate (HR) was increased by right atrial pacing at 120 bpm. 11 other patients exercised using a supine cycle ergometer at increasing workload. Net wave intensity was computed as dI= (dPd/dt)(dU/dt) and the energy of the FW and BW waves was derived by the areas under the curve. Results: Resting values of systemic and coronary hemodynamic were similar in both groups, with HR = 73 ±4 bpm, Pa = 104 ±5 mmHg, Pd = 85 ±10 mmHg and U = 16.2 ±2.1 cm/s. Exercise increased HR to 108 ±7 bpm which did not differ from that during pacing. Pa and Pd increased with exercise by 20 mmHg and 8 mmHg, resp. (p&lt;0.05), whilst pacing raised Pa by only 5 mmHg (p&lt;0.05) at unchanged Pd. U similarly increased to 23.1±3.0 cm/s by pacing and exercise. Coronary wave energy at rest was the same for both groups. The BW compression wave more than doubled with both pacing and exercise, while the early FW compression wave was unchanged by exercise and much reduced by pacing from 1.9 ± 0.6 to 0.3±0.1 Jm -2 s -2 (p&lt;0.05). The FW expansion wave at the onset of relaxation increased from 1.6±0.5 to 3.5±1.0 Jm -2 s -2 (p&lt;0.05) with exercise but was not altered by pacing. The BW expansion wave that drives diastolic coronary flow more than doubled with exercise, but only increased by 63% with pacing. Conclusion: Exercise more profoundly affects cardiac-coronary interaction than pacing and improves the energy of FW and BW waves during cardiac relaxation. This is likely due to increased contractility, assisted by added reflection from the systemic circulation that enters the coronary arteries via the aorta.
Abstract 19038: Epigenetic Regulation of Canonical TNFa Pathway by HDAC1 Determines Survival of Cardiac Myocytes
Authors: Lorrie Kirshenbaum, Hongying Gang, James Shaw, Rimpy Dhingra
Journal: Circulation (2013)

Gene transcription is regulated by post-translation modifications. Histone deacetylases (HDACs) remove acetyl-groups from histone and non-histone factors inhibiting transcription. Pro-inflammatory cytokines such as TNFα activate the canonical Nuclear Factor -κB (NF-κB) pathway. Earlier we established a cytoprotective role for NF-κB in the heart. Though a causal relationship for HDAC1 and NF-κB has been established, the impact of HDAC1 on TNFα signaling is unknown. Herein, we demonstrate HDAC1 provides a molecular switch for determining cell survival in the TNFα pathway. In contrast to vehicle treated control cells, TNFα treated cells displayed a marked increase in NF-κB gene transcription. Notably, cells treated with TNFα were indistinguishable from vehicle controls cells with respect to viability. Interestingly, HDAC activity was reduced in cells treated with TNFα. Conversely, in the presence of HDAC1, NF-κB gene transcription by TNFα was repressed, resulting in mitochondrial perturbations and widespread cell death. Heterologous fusion proteins comprised of yeast Gal4 DNA binding domain fused in frame to the NF-κB p65 transactivation domain were preferentially repressed by HDAC1. Moreover, transcription mediated by Gal4VP16 protein from herpes virus was unaffected by HDAC1 in cardiac myocytes. Mutations that abrogate known catalytic activities of HDAC1, small interference RNA or pharmacological inhibition of HDAC1, restored NF-κB signaling and suppressed cell death induced by TNFα. These data provide the first evidence for an obligate link between HDAC1 and canonical TNFα pathway for cell survival of cardiac myocytes.
Abstract 19015: Loss of Plasma Proprotein Convertase Subtilisin/Kexin 9 (PCSK9) After LDL Apheresis
Authors: Hagai Tavori, Ilaria Giunzioni, MacRae F Linton, Sergio Fazio
Journal: Circulation (2013)

Low-density lipoprotein (LDL) apheresis (LDL-A) is used to reduce LDL levels in patients with severe familial hypercholesterolemia (FH). We, and others, have previously reported that up to 40% of plasma PCSK9 is bound to LDL, while the rest is with the apoB-deficient fraction. Therefore, we examined whether LDL-A treatment using dextran-sulfate columns (Liposorber®) affects plasma PCSK9 levels. Pre and post apheresis plasma from five FH patients in three consecutive treatment cycles was used to determine changes in PCSK9 levels. Lipid, albumin, CK-MB, and creatinine levels were also evaluated. LDL-A treatment, as expected, significantly reduced plasma LDL (by 85±6%). In addition, PCSK9 levels fell by 52±7%, and this decrease was significantly correlated with the LDL drop (p=0.02, r 2 =0.304 ), but not with decreases in triglyceride or HDL levels. Levels of other plasma analytes (albumin, creatinine, CK-MB) did not show changes after apheresis treatment. Similar to LDL, PCSK9 levels returned to pre-treatment values between cycles (2-week intervals). Fractionation of pre and post plasma showed that 87±4% of LDL-bound PCSK9 and 38±14% of the PCSK9 associated with the apoB-deficient fraction were removed. From the column eluate we recovered more than 80% of the PCSK9 removed from the circulation. Running human plasma, isolated LDL and apoB-deficient plasma through a scaled-down apheresis column we again found a loss of 57% of total PCSK9, including 89% of LDL-bound PCSK9 and 41% of the PCSK9 associated with the apoB-deficient fraction. These decreases in PCSK9 levels are in the range of what is accomplished with current anti-PCSK9 antibody therapies. These results show for the first time that dextran-sulfate LDL apheresis substantially reduces levels of plasma PCSK9. This likely represents an additional benefit of the apheresis treatment in keeping LDL levels down over time and may contribute to the prevention of cardiovascular events in FH patients undergoing apheresis. We also provide additional proof that more than one third of plasma PCSK9 is on the circulating LDL. These findings may guide use of future anti-PCSK9 therapies in LDL-A patients, and should lead to wider indications for LDL-A, beyond the most severe FH presentations.
Abstract 19003: The Molecular Basis of Cooperative Transcriptional Regulation by Foxo1 and Ets1 on a Conserved Endothelial Cell-Specific Enhancer Site Determined by the Ternary Complex Crystal Structure
Authors: Gabriel Birrane, Wing C Choy, Catherine A Geiger, Marianne A Grant
Journal: Circulation (2013)

Establishment and maintenance of the vasculature is mediated by a highly organized transcriptional program requiring the correct spatial and temporal expression of a large number of genes. Evidence suggests that endothelial-specific gene expression may be regulated combinatorially by transcription factor partnerships. However, no understanding of the molecular basis for mechanisms governing endothelial-specific synergistic gene expression yet exists. Here, we show the molecular basis for a transcription factor partnership on an enhancer that is sufficient to direct expression specifically and exclusively to the developing vascular endothelium. This cis -acting enhancer element is bound and activated by Forkhead (FOX) and ETS transcription factors and also plays a role in the expression of genes important for adult neovascularization and vascular integrity. We have determined the 2.7Å resolution crystal structure of the DNA-binding domain of FOXO1 (FOXO1-DBD) and the DNA-binding domain of ETS1 (ETS1-DBD) bound to a 21-bp DNA duplex of the composite FOX:ETS endothelial-specific site. The ternary complex structure reveals the ETS1-DBD α/β architecture with three α-helices packed against four antiparallel β-strands to form a ‘winged helix-turn-helix’ topology and with helix-α3 embedded in the major groove. FOXO1-DBD in the complex displays a ‘winged-helix’ architecture with helix-α3 binding the major groove base sequence AATAA. Loop region H2-H3 of FOXO1-DBD is stabilized into a unique conformation to make salt-bridge mediated contact with ETS1 in the minor groove. The ternary complex structure reveals the molecular details of selective recruitment of FOXO1 by ETS1 to this non-canonical FOX:ETS site. These findings are supported by EMSA studies showing FOXO1-DBD binds poorly to FOX:ETS DNA in the absence of ETS1-DBD and underscores the cooperativity of ETS and FOX activities on the cis -acting sequence. This important ternary complex provides understanding of how FOX and ETS synergistically mediate transcriptional activity on an enhancer directing expression specifically and exclusively to the developing vasculature, as well as cooperatively regulate gene expression in adult neovascularization and vascular hemostasis.