tbuckley/cabot-search huggingface dataset:
Abstract We068: TRAF6 Mediates TFEB Ubiquitination to Inhibit Cardiomyocyte Autophagy in Sepsis-Associated Cardiac Dysfunction
Authors: Xiaoping Wang
Journal: Circulation Research (2024)

Sepsis-associated cardiac dysfunction (SACD) is the predominant cause of death in patients with severe sepsis. Complex mechanisms have been proposed for SACD, including maladaptive inflammation and autophagy. However, studies in the past have emphasized these different manifestations underlying SACD as discrete processes and largely neglect their inherent connection. Herein using both in vivo and in vitro SACD models, we showed that the cardiomyocyte Toll-like receptor 4 (cTLR4) can serve as a key receptor mediating the interaction between the cardiomyocyte and macrophage under SACD-like conditions. The stress-induced secretome of macrophage caused activation of cTLR4 which intensified the impairment of autophagic flux in cardiomyocytes. The TNF receptor-associated factor 6 (TRAF6) was further identified as the primary downstream target which conferred the regulatory effects of TLR4 signaling on cardiac autophagy. Importantly, we found that cardiac targeted Traf6 gain-of function exacerbated, while cardiac targeted Traf6 loss-of function partially rescued, the cardiac dysfunction in a mice model of SACD. Mechanistically, TRAF6 functioned as a ubiquitin E3 ligase to facilitate the degradation of transcription factor EB (TFEB) via ubiquitination and subsequently led to the blockage of autophagic flux. Along the line, dynamics computational simulation combined with experimental validation revealed unique local electrostatic interactions between human TRAF6 and TFEB. Overall, our study provides novel mechanistic supports which link the macrophage-initiated inflammation and cardiomyocyte autophagy, demonstrates a previously undescribed role of cTLR4/TRAF6/TFEB signaling in fine-tuning cardiac autophagy, and highlights TRAF6 as a novel therapeutic gene target to develop autophagy-based therapeutics for SACD.
Abstract We079: Program Macrophage Phenotypes and Cardiac Remodeling After Myocardial Infarction with Interleukin-10
Authors: William CW Chen, Jing Zhang, Xiaoping Li, Kang Kim, Johnny Huard, Rodrigue Rizk, Yadong Wang
Journal: Circulation Research (2024)

Introduction: Macrophages (Mφ) and their phenotypic polarization play essential roles in modulating cardiac inflammation and recovery after myocardial infarction (MI). Interleukin-10 (IL-10) is a potent immunomodulatory cytokine that directs Mφ polarization to beneficial reparative phenotypes and is widely investigated in diseases involving extensive inflammation. However, high-dose IL-10 treatment may not lead to the expected therapeutic outcome, raising the question of whether IL-10 has dose-dependent effects on Mφ polarization and cardiac remodeling post-MI. Hypothesis: IL-10 can program Mφ phenotypes under inflammation and has functional impact in cardiac remodeling post-MI in dose-dependent manner. Goals: We use RAW264.7 Mφ and mouse permanent MI models to test our hypothesis. Approach: We applied 25-1000 ng/mL IL-10 in vitro before or after inducing M1 (with interferon-g) and M2 (with interleukin-4) polarization for pro-inflammatory and anti-inflammatory phenotypes, respectively. We intramyocardially administered 25-2000 ng IL-10 in vivo immediately after inducing MI and examined cardiac function, inflammatory responses, fibrosis and revascularization for 6 weeks (n=5/group). Results: IL-10 at 100-250 ng/mL directed Mφ phenotype shift from M1 to M2 most effectively after inducing polarization in vitro (both p &lt;0.01); groups with ≥500 ng/mL IL-10 exhibited high M1/low M2 phenotypes, similar to no IL-10 controls. Cells treated with ≥100 ng/mL IL-10 before polarization exhibited a notable reduction in M1 phenotype after induction (all p &lt;0.05). Echocardiography showed that with single IL-10 administration, only 250 ng IL-10 notaly improved left ventricular (LV) function and reduced LV chamber size compared with the saline control ( p &lt;0.05) whilst ≥1000 ng caused a transient negative impact in LV function at 5 days post-MI ( p &lt;0.05), Phagocyte infiltration at MI was notably diminished in ≥100 ng groups at 6 weeks post-MI (all p &lt;0.05). Only 250 ng IL-10 led to a notable 53% reduction in LV fibrosis ( p =0.05) and nearly 200% increase in CD31+ cell counts at MI ( p =0.013). Conclusion: Our results suggest an optimal range of IL-10 doses for macrophage polarization and cardiac benefits post-MI, with risks of side effects from IL-10 overdose.
Abstract We093: Comparative Analysis of Theoretical Models and Fusion Frameworks for Early Cardiac Dysfunction Detection Using Multimodal Wearable Data
Authors: Poonam Tawde
Journal: Circulation Research (2024)

Background: Wearable devices have emerged as promising tools for continuous monitoring of physiological signals, offering opportunities for early detection of cardiac dysfunction. This study aims to compare various theoretical models and fusion frameworks to assess their effectiveness in early detection of cardiac dysfunction. Hypothesis: The study investigates the performance of signal processing-based, machine learning-based, and hybrid models for early cardiac dysfunction detection using multimodal wearable data. Additionally, it explores the efficacy of feature-level fusion, decision-level fusion, and sensor-level fusion frameworks in integrating information from diverse sensors for enhanced detection accuracy.The primary goal of the study is to identify the most effective theoretical models and fusion frameworks for early detection of cardiac dysfunction using multimodal wearable data. By comparing different approaches, the study aims to provide insights into the strengths and limitations of each method and contribute to the development of reliable wearable-based systems for proactive healthcare interventions. Methods/Approach: Three theoretical models—signal processing-based, machine learning-based, and hybrid—were implemented and evaluated for their performance in detecting early signs of cardiac dysfunction. Additionally, three fusion frameworks—feature-level fusion, decision-level fusion, and sensor-level fusion—were investigated to assess their effectiveness in integrating multimodal wearable data. Results/Data: The signal processing-based model achieved a sensitivity of 85%, specificity of 82%, and accuracy of 83% in detecting early signs of cardiac dysfunction. The machine learning-based model outperformed with a sensitivity of 92%, specificity of 88%, and accuracy of 90% . The hybrid model yielded intermediate results with a sensitivity of 89%, specificity of 85%, and accuracy of 87% . Among the fusion frameworks, sensor-level fusion demonstrated superior performance with a sensitivity of 94%, specificity of 90%, and accuracy of 92%. Conclusion: Machine learning-based approaches showed higher efficacy in early cardiac dysfunction detection compared to signal processing-based methods. Sensor-level fusion exhibited the best performance among data fusion frameworks, emphasising the importance of integrating information from diverse wearable sensors for improved accuracy.
Abstract We083: A new mouse model for the study of cardiogenic TFs <i>Tbx5</i> , <i>Gata4</i> , and <i>Mef2c</i> during cardiogenesis
Authors: Riley Leonard, Mason Sweat, Steve Eliason, Kathy Zimmerman, Yi Zhao, Xiao Li, Cathy Hatcher, Robert Weiss, Brad Amendt
Journal: Circulation Research (2024)

Congenital heart defects (CHDs) are be caused by mutations in genes that drive cardiac development, such as Tbx5 , Gata4 , and Mef2c . Cardiac development, and its transcriptional regulators are also regulated by microRNAs (miRs). These small RNAs target the transcripts of genes in numerous cardiac cell types during embryonic development. We and others have shown that the miR-200 family modulates the transcripts of cardiogenic transcription factors (TFs) Tbx5 , Gata4 , and Mef3c. However, the relationship between these miRs and cardiogenic TFs during in vivo cardiac development is poorly understood. During cardiogenesis, miR-200 family members are highly expressed (E14.5) but reduced in adults (3mo) (Ct Value: miR-200a : 24.3 ± 0.59 v 38.3 ± 0.21; miR-200c : 25.0 ± 0.64 v 32.5 ± 0.16). Using our miR-200 family inhibitor mice models (PMIS), we have found these miRs are required for cardiac development. PMIS-miR-200 embryos are found with a ventral septal defect and poor ventricle wall development, which is lethal by e16.5. At e14.5, PMIS-miR-200 hearts have a significant increase in expression of Tbx5, Gata4, and Mef2c compared to Wild-Type. This induced expression of these TFs is seen within CMs of the ventricle at E14.5. snMulti-Omics of WT and PMIS-miR-200 hearts found a population of CMs enriched in the PMIS-miR-200 hearts. These CMs are marked by expression of Tbx5 , Nppa , and Sox5 . RNA velocity analysis found these CMs to be “progenitor-like” and associated with an early pseudotime. Expression of Tbx5 , Nppa , and Sox5 correlated along the pseudotime with the “progenitor-like” CMs. ATAC-seq showed enrichment of Tbx5 and Mef2c motifs within this new CM cell state. Conclusions: The miR-200 family is a modulator of cardiogenic TFs expression and activity during development. Inhibition of miR-200 induces a CM cell state with “progenitor-like” qualities. Future directions will determine the role of miR- 200 in adult cardiac disease, such as ischemic injury. Our work provides new insights into gene dosage, modulated by miRs, that is required and necessary during cardiac development.
Abstract We053: Altered inflammatory state and mitochondrial function identified by transcriptomics in paediatric congenital heart patients prior to surgical repair
Authors: Francesca Bartoli-Leonard, Amy Harris, Massimo Caputo
Journal: Circulation Research (2024)

Background: Congenital heart disease (CHD) remains the most common birth defect, with surgical intervention required in complex cases. In contrast to adult heart disease which disproportionately affects the left ventricle, complex CHD can be characterized by increased right ventricular (RV) pressure, leading to RV hypertrophy and eventually failure, with RV function known to be a major predictor in sustained cardiac health in these patients. Methods: RV samples were collected from discarded myocardial tissue from paediatric patients (0-16 years) undergoing their first cardiac surgery at Bristol Royal Hospital for Children or obtained from autopsy subjects. RNA sequencing and subsequent cellular deconvolution was conducted in CHD samples and integrated with publicly available control dataset. Cellular deconvolution, pathway network analysis and gene ontology were conducted and changes in expression of markers was confirmed via histological analysis. Results: Presence of CHD drove divergence of transcriptome with 511 differentially expressed genes (log fold change≥±2, padj≤0.05), with 82% shared homology. Known CHD genes; TBX5 , JAG1, NOTCH2 and NOTCH1 were reduced in CHD compared to controls (padj=2.24 E-07 , 1.38 E-27 , 7.76 E-31 , 9.11 E-7 ) . Conversely, mitochondrial dysfunction genes RPPH1 and RMPR (padj=4.67 E-132 , 2.23 E-107 ) were increased. Gene set enrichment identified mitochondrial dysfunctional pathways.Negative regulation of mitochondrial functions and metabolism was identified in functional network analysis. T helper cell markers CD4 and SELL were significantly downregulated (p&lt;0.0001, p=0.003). Cytotoxic T cell markers CD8a, LAGE3 and CD49a were significantly increased in CHD compared to control (p=0.0006, p&lt;0.0001, p=0.0118) as was proinflammatory marker Caspase1 (p=0.0055). Histological analysis confirmed an increase in CD45 and CD8 positive cellular bodies with the CHD tissue, which was absent in control. Deconvolution of bulk RNAseq data suggests a reduction in CD4+ T cells (p=0.0067) and an increase in CD8+ T cells (p=0.0223). Network analysis identified positive regulation of the immune system and cytokine signalling clusters within the inflammation functional network as were lymphocyte activation and leukocyte differentiation. Conclusions: Utilizing RV tissue from paediatric patients undergoing CHD cardiac surgery this study identifies dysfunctional mitochondrial pathways and an increase in inflammatory T cell presence prior to reparative surgery.
Abstract We052: Angiotensin-converting enzyme (ACE): A new role to regulate β-oxidation in monocytic cells
Authors: Duo-Yao Cao
Journal: Circulation Research (2024)

The metabolic failure of macrophages to adequately process lipid, and the deleterious effects of ingested lipid on macrophage behavior, is central to the etiology of atherosclerosis. As angiotensin-converting enzyme (ACE) has major effects on myeloid cell metabolism, we examined the role of macrophage ACE in a mouse model of atherosclerosis. Animals with increased macrophage ACE expression (ACE 10/10 mice) have a marked reduction in atherosclerosis vs. WT mice. Macrophages from both the aorta and peritoneum of ACE 10/10 express increased PPARα and higher levels of effector molecules downstream of PPARα. These macrophages have increased basal and maximal oxygen consumption compared to WT macrophages. When exposed to lipid in vitro, ACE 10/10 macrophages ingest more fatty acid than WT and have increased efferocytosis. ACE 10/10 macrophages metabolize via β oxidation far more fatty acid than WT cells as determined using 13C isotope tracing. In part by increasing PPARα, ACE boosts myeloid metabolic function under pathophysiologic lipid stress, addressing a key myeloid failure in atherosclerosis.
Abstract Tu104: Mitochondrial Hydrogen Sulfide Regulates Skeletal Muscle Dysfunction and Exercise Intolerance in Cardiometabolic HFpEF
Authors: Timothy Allerton, Jake Doiron, Mahmoud Elbatreek, Zhen Li, James Stampley, Gregory Davis, Robert Noland, Brian Irving, Thomas Sharp, Huijing Xia, Sanjiv Shah, David Lefer
Journal: Circulation Research (2024)

Introduction: Cardiometabolic heart failure with preserved ejection fraction (HFpEF) results in severe exercise intolerance. Dysregulated skeletal muscle metabolism and mitochondrial function are key drivers of exercise intolerance in cardiometabolic HFpEF. Mitochondrial hydrogen sulfide (H 2 S) generated by 3-mercaptopyruvate sulfur transferase (3-MST) exerts potent bioenergetic properties. We have recently shown that H 2 S bioavailability is significantly attenuated in HFpEF. The role of H2S in skeletal muscle metabolism and exercise tolerance in HFpEF is currently unknown. Hypothesis: We tested the hypothesis that the loss of skeletal muscle H 2 S results in metabolic dysfunction in skeletal muscle and contributes to exercise intolerance in cardiometabolic HFpEF. Methods: Skeletal muscle (gastrocnemius) from L-NAME + High Fat diet (“two-hit”) treated, and chow-fed control male mice (n=10/group) were assessed for free H 2 S and 3-MST enzymatic activity using GC-chemiluminescence detection. Additionally, muscles were processed for RNA sequencing. Next, male global 3-MST knockout (KO) mice (n=12) and controls (n=10) were subjected to “two-hit” HFpEF for 10 weeks, and exercise tolerance was evaluated. Skeletal muscle (soleus and gastroc) was subjected to high-resolution respirometry and substrate oxidation of radiolabeled isotope ( 14 C) for leucine and palmitate. Results: Skeletal muscle H 2 S levels (0.73 ± 0.18 vs. 1.0 ± 0.24 nmol/g/tissue) and 3-MST activity (0.46 ± 0.01 vs 0.57 ± 0.01 µmol/g/tissue/min) were significantly (p &lt; 0.05) reduced in “two-hit” HFpEF mice compared to control mice. At the transcriptome level, 3-MST was one of the top 50 differentially regulated genes (i.e., reduced expression) in “two-hit” mice (Adjusted p=0.01). Genetic deficiency of 3-MST KO mice exacerbated (p &lt; 0.05) exercise intolerance as measured by treadmill running distance (53 ± 24 vs. 138 ± 104 meters) vs. “two-hit” HFpEF genotype controls. Mitochondrial Complex I (low ADP) respiration was reduced by 23% in 3-MST KO HFpEF mice (p &lt; 0.05). Genetic deficiency of 3-MST also reduced skeletal muscle leucine oxidation (58 ± 19 vs 84 ± 8; p = 0.01) and dramatically increased incomplete palmitate oxidation by 2.5-fold (p &lt; 0.001) without changing complete oxidation. Conclusion: We demonstrate that skeletal muscle mitochondrial H 2 S is a critical regulator of metabolic function and exercise capacity in cardiometabolic HFpEF.
Abstract Mo050: Fluoroquinolones and the Risk of Aortic Aneurysm or Aortic Dissection: Evidence From a Nationwide Nested Case-Control Study Paralleled With Matched Experimental Models
Authors: Callan Wesley, Jarl Strange, Anders Holt, Gunnar Gislason, Cedric Neutel, Dustin Krüger, Celine Civati, Mart Theunis, Tania Naessen, Lynn Roth, Guido De Meyer, Wim Martinet, Peter Vibe Rasmussen, Pieter-Jan Guns
Journal: Circulation Research (2024)

Background and Aims: Fluoroquinolones (FQ) have been linked to aortic aneurysms and dissections (AA/AD), resulting in an official warning. However, recent large-scale epidemiological studies have reported lack of FQ-AA/AD association. This study aimed to scrutinize FQ-AA/AD risk by implementing a combined epidemiological and experimental approach. Methods: Danish nationwide registers (2003-2021) were used for a nested case-control analysis. FQ-AA/AD risk was evaluated in a main and high-risk FDA cohort. Further, mortality and aortic interventions linked to FQ were investigated in patients with aortic disease. Additionally, ciprofloxacin (100 mg/kg/day, 2x2 weeks) was administered to wild-type, hypertensive or Marfan mice. Aortic diameters and pulse wave velocity (PWV) were measured longitudinally to investigate aortic remodelling. Results: The main cohort comprised 5.10 million individuals with 58,919 cases and 1,767,510 sampled controls. Compared with amoxicillin exposure. FQ exposure was not associated with increased AA/AD risk (30-day hazard ratios (HR) 1.00 [95% confidence intervals (CI): 0.74-1.34]; 90-day HR 1.07 [CI 0.94-1.22]; 1-year HR 0.95 [0.90-1.01]). In a high-risk cohort, there was no FQ-AA/AD association (30-day HR 0.83 [0.61-1.12]; 90-day HR 0.99 [0.86-1.15]; 1-year HR 0.97 [0.90-1.05]). In patients with aortic disease, FQ were not associated with increased aortic interventions or mortality (30-day HR 0.98 [0.79-1.22]; 90-day HR 1.06 [0.95-1.19]). Additionally, ciprofloxacin did not affect aortic diameters or PWV in wild type, hypertensive, and Marfan mice, while differences between models proved the sensitivity of the methodology. Conclusion: The data clearly do not support the current precautions and warnings pertaining to risks of aortopathies and FQ should not be discouraged when clinically indicated.
Abstract We042: Gelatin hydrogel elasticity influences TBX18-induced pacemaker cell behavior
Authors: Younghwan Choi, Jinqi Fan, Hee Cheol Cho
Journal: Circulation Research (2024)

Introduction: Extracellular matrix (ECM) stiffness plays a role in determining cell behavior during development and maintenance of organ function. Polystyrene dishes typically show an elastic modulus of 1 gigaPa, which is far from the elastic modulus of 10 to 15 kiloPa for myocardium. Gelatin, a derivative of collagen, is a major structural scaffolding in the myocardium including the sinoatrial node. Hypothesis: We hypothesized that gelatin hydrogel at varying stiffness serves as a platform to modulate the automaticity of cardiac pacemaker cells. Methods: Freshly isolated neonatal rat ventricular myocytes (NRVMs) were cultured as monolayers on regular, plastic cell culture plate or on 3%, 5%, and 10% gelatin hydrogel that represents a stiffness of 1.3 ± 0.3, 6.4 ± 1.5, and 13.6 ± 3.5 kPa, respectively. All cell culture surface was coated with fibronectin. NRVMs were transduced with Adv-TBX18 or Adv-GFP at day 0 (d0). Results: TBX18-NRVMs showed significantly more spontaneous synchronous contractions on the gelatin hydrogel (22 ± 12, 29 ± 1, 33 ± 9 on 3, 5, or 10% gelatin, respectively) than on plastic (10 ± 11) at d4. Control, GFP-NRVMs showed few spontaneous synchronous contractions regardless of the cell culture platform (3 ± 4, 2 ± 3, 0 ± 0 bpm at 3, 5, 10% gelatin, respectively; 3 ± 7 bpm on plastic, n = 5 to 6 wells/group) at d4. TBX18-NRVMs exhibited significantly more spontaneous synchronous Ca 2+ transients/min on 10% gelatin hydrogel (33 ± 2) than on 3% gelatin hydrogel (9 ± 2) or 5% gelatin hydrogel (19 ± 8) (n = 3, p&lt;0.05) at d8. Immunostaining revealed that Hcn4 protein expression in TBX18-NRVMs was higher on 10% gelatin than on plastic at d2. The percentage of vimentin+ nonmyocytes in TBX18-NRVMs was higher on 10% gelatin (39.5 ± 2.2 %) compared to either on 5% (26.6 ± 1.7%) or on 3% gelatin (27.5 ± 4.2) at d6. Conclusions: Our data indicate that spontaneous and synchronized contractions of TBX18-induced pacemaker cells were significantly higher on gelatin hydrogel with myocardium-like stiffness compared to those grown on plastic culture medium. The data suggest that modulating ECM stiffness may impact the automaticity of cardiac pacemaker tissues, and could serve as a platform to study sinus node dysfunction.
Abstract We043: MYCN is a regulator of cardiomyocyte proliferation and regeneration in the mammalian heart
Authors: Satyabrata Das, Thijs Larson, Javier Sierra-Pagan, Tamas Alexy, qinglu li, Xiao Ma, Wuming Gong, Hesham Sadek, Mary Garry, Jianyi Zhang, Daniel Garry
Journal: Circulation Research (2024)

The identification of new factors and mechanisms that can promote the repair and regeneration of the adult injured mammalian heart are necessary as the adult heart has limited ability to repair itself. We identified MYCN as a downstream effector of the sonic hedgehog (SHH) signaling cascade during cardiomyocyte proliferation in the neonatal heart. Although the protooncogene, MYCN, has been shown to be an essential factor during embryonic heart development, its role in regenerating the adult heart has not been established. Here, we define MYCN as a critical regulator of cardiomyocyte (CM) proliferation and regeneration using genetic mouse models and in vivo modified RNA (modRNA) delivery. In these studies, we conditionally deleted Mycn in the neonatal heart (P0). Immunohistochemical (IHC) analysis of P3 neonatal hearts demonstrated significantly (p &lt; 0.05) decreased expression of Ki67 and pH3 in the absence of Mycn compared to control (no 4-OHT) hearts. This observation was further validated in isolated CMs and neonatal P7 hearts pulsed with EdU which demonstrated a significant decrease in EdU+ CMs in the absence of Mycn compared to control. Single-nucleus RNA-sequencing results from control and Mycn CKO P4 ventricles revealed a severe depletion of the proliferative and regenerative cardiomyocyte population in the Mycn CKO hearts. We then ligated the left anterior descending coronary artery (LAD) to produce an ischemic cardiac injury in control and Mycn CKO P2 neonatal mice. Echocardiography one-month following the LAD surgeries demonstrated that the Mycn CKO failed to recover baseline cardiac function compared to their control counterparts who achieved complete recovery. RNAseq analysis of control and Mycn CKO hearts 1 month following LAD ligations demonstrated that muscle developmental pathways were significantly downregulated in the Mycn CKO group compared to the control. We then delivered either GFP (control) or Mycn modRNA intramuscularly into the border zone following LAD coronary artery ligation surgeries in adult (2-6 month old) mice. We observed that the Mycn modRNA treated mice had significantly improved cardiac function at one month and two months following injury/delivery compared to controls. These results identify MYCN as an important regulator of CM proliferation and heart regeneration.