tbuckley/cabot-search huggingface dataset:
Abstract We047: Enhanced Vascularization in hPSC-derived Cardiac Organoids by Dynamic Culture
Authors: Angello Huerta Gomez, Soo-Yeon Kang, Marcel El-Mokahal, Moo-Yeal Lee, Huaxiao Yang
Journal: Circulation Research (2024)

Introduction: Human pluripotent stem cells (hPSC)-derived cardiac organoids (COs) have gained increasing interest in biotechnology due to their characteristics like diverse cardiovascular cell types, 3D complex structure, and function that recapitulates the human heart in early development. However, current methods for vascularizing COs are not systematic and robust. Hypothesis: We hypothesize that culturing hPSC-derived COs dynamically will further enhance vascularization in COs. Materials and Methods: Two conditions were created to compare vascularization in COs: 1) dynamic culturing (Dyn) and 2) static culturing (St). Firstly, hPSCs were cultured for two days in ultra-low attachment plates to develop spheroids. The spheroids were then transferred to pillar plates followed by direct cardiac differentiation the next day. Live-cell imaging was used to monitor the process of vascularization for up to 16 days and the corresponding fluorescence intensity of each cell type from its reporter expression was analyzed. The cardiac function was measured by video-based contractility analysis. Data were presented as mean ± standard error of the mean (SEM). The student’s t-test was used for the statistical analysis. Results: Cardiomyocytes (CMs) and endothelial cells (ECs) were imaged on pillars under the two conditions as shown in Fig. 1A . Successful cardiac differentiation was present, displaying hPSC-CM contraction on day 12 and onwards. Higher intensity values of hPSC-CMs under Dyn were observed in all four days compared to St as shown in Figs. 1B&amp;C . The hPSC-ECs intensity displayed greater intensity values compared to St, demonstrating enhanced vascularization in VCOs due to the active Dyn as shown in Figs. 1D&amp;E . The functionality was improved in Dyn as indicated with higher contraction velocity as shown in Fig. 1F. Conclusion: This study demonstrates the effects of incorporating dynamic culture for enhancing cardiogenesis and vasculogenesis in hPSC-derived COs. The enhanced hPSC-VCOs hold promise for studying early cardiovascular development, congenital heart disease modeling, and drug screening and discovery.
Abstract Mo064: Na <sup>+</sup> leak channel NALCN plays an essential role in mineralocorticoid-induced hypertension through nonrenal mechanisms.
Authors: HYE RYEONG LEE, solah park, DONG JUN SUNG, JIN RYEOL AN, MI SEON SEO, HYUN JU NOH, SUNG HEA KIM, BO KYUNG KIM, SANG WOONG PARK, Young Min Bae
Journal: Circulation Research (2024)

In human and animal hyperaldosteronism-related hypertension, the increased blood volume has been regarded as a primary contributor to hypertension generation. However, increases in arterial contractility (and thus peripheral resistance) are also frequently reported in various hypertension models, including the mineralocorticoid-induced hypertensions such as DOCA-salt hypertension. Moreover, non-renal mechanisms (i.e., direct regulation on the cardiovascular ion channels) of the mineralocorticoid-induced hypertension are reportedly important. Na + -leak channel (NALCN) was first cloned as Na + /Ca 2+ channel family in 1999. However, its role in providing background cation conductance and contributing to normal neuronal excitability has been uncovered relatively recently and little is known about the roles of NALCN in cardiovascular system and pathogenesis of hypertension. Here, we show that aldosterone directly upregulates NALCN expression in arterial smooth muscle independent of kidney and contribute to the increases in arterial contractility, thereby contributing to the development of hypertension. Remarkably, mere the transient knockdown of arterial NALCN greatly ameliorated the development of hypertension along with arterial hypercontractility. Moreover, it is very interesting that our findings suggest that NALCN is activated by oxidative stimuli and this activation can be prevented by -gliflozin series SGLT2 inhibitors. From these, we propose that NALCN is a very promising and potent target for the treatment of various hypertensions including mineralocorticoid-related one.
Abstract We044: MATURITY OF HUMAN INDUCED PLURIPOTENT STEM CELL-DERIVED CARDIOMYOCYTES PROMOTED BY BRACHYURY PRIMING
Authors: Parisa Kargaran, Armin Garmany, Ramin Garmany, Marissa Stutzman, Maryam Sadeghian, Michael Ackerman, Atta Behfar, Andre Terzic
Journal: Circulation Research (2024)

Introduction: Cardiac differentiation protocols enable derivation of cardiomyocytes (CM). from human induced pluripotent stem cell (iPS). However, limited tools are available to ensure enhanced iPS-CM maturation without the need for prolonged and complex culture. Research Question: This study assessed whether the mesodermal and cardiopoiesis inductor, Brachyury (T), complements standard cardiac differentiation and augments structural and functional maturation of iPS-CM. Aims: The impact of T mRNA introduction prior to initiation of cardiac differentiation was characterized on: i) cardiac transcription factor expression; ii) structural and functional hallmarks of maturity; and iii) cardiotoxicity. Methods: RT-qPCR was employed to monitor the expression of cardiac-specific transcription factors. Transmission electron microscopy enabled the assessment of cellular ultrastructure. Seahorse measurements were used to determine basal respiration. Fluo4 staining was used to measure calcium transients with external field stimulation. Cardiotoxicity was measured as the impact of doxorubicin on calcium handling and cell survival. Results: Transfection with T prompted early and sustained upregulation of the cardiac transcription factors Nkx2.5 (10-fold; FDR&lt;0.001) and MEF2C (7.2-fold; FDR&lt;0.001). Mitochondrial area was increased with T transfection (P&lt;0.001) and T-transfected iPS-CM exhibited greater basal respiration (FDR&lt;0.05), greater calcium handling resilience in response to field stimulation, and a more mature transient morphology. Following doxorubicin exposure T transfected iPS-CM exhibited a greater compromise in calcium handling (FDR&lt;0.001), and exaggerated cell death. Conclusion: Induction of human iPS with T prior to initiation of cardiac differentiation enhanced signatures of structural and functional maturity, and provided more robust readouts of drug toxicity.
Abstract Mo061: The major voltage-gated sodium channel accessory subunit in working ventricular myocytes may be β1B, not β1
Authors: Zachary Williams, Dean Neutel, Laura Payne, Jane Jourdan, Robert Gourdie
Journal: Circulation Research (2024)

Voltage-gated sodium channels, crucial for the action potential upstroke in cardiomyocytes, consist primarily of a single pore-forming α-subunit and 1 or 2 accessory β-subunits. SCN1B encodes two variants: β1, a transmembrane cell adhesion molecule, and β1B, typically described as a soluble secreted protein. While β1 and β1B share identical sequences in the amino-terminal (NT) extracellular Ig domain, they differ in their carboxy-terminal (CT) sequence. The Ig domain of β1/β1B has been deemed critical in maintaining normal cardiac conduction by various groups. Traditionally, effects on cardiac conduction have been attributed to β1, despite difficulties in detecting it at the protein level in the heart. We hypothesized that β1B, rather than β1, plays a significant role in electrical activity propagation in the heart. Utilizing an NT antibody (detects both variants), a β1-specific CT antibody, and a custom β1B-specific CT antibody, we examined SCN1B gene product profiles in various cardiac cell types, including neonatal rat ventricular myocytes and fibroblasts (NRVMs and NFs), isolated adult mouse cardiomyocytes (MCMs), and tissue slices from isolated adult rat hearts. The β1-specific CT antibody failed to label any bands in Western Blots (WB) of these cells and tissues, whereas the NT antibody detected a 37 kD band in all cell types and showed high levels of localization at cell-cell contacts using immunofluorescence (IF) with NRVMs. Conversely, the CT antibody showed minimal immunolabeling evidence. Moreover, an inhibitor of β1 Regulated Intramembrane Proteolysis failed to generate the expected 19 kD fragment if β1 were present in NRVMs. In adult rat hearts, the NT antibody labeled intercalated discs, while the CT showed minimal signal. Conversely, in WBs of NRVMs using our custom β1B antibody, we observed a 37 kD band consistent with the presence of β1B, and in heart sections, we found labeling of intercalated discs. These findings suggest that the major β subunit in working ventricular myocytes may be β1B, not β1. Further investigation is warranted, as these results could significantly impact our understanding of the roles and functional effects of β1 and β1B on cardiac conduction.
Abstract We086: Identifying Gene Regulatory Subnetwork Drivers of Cardiomyocyte Chamber Specification
Authors: Alexander Clark, Jeffrey Saucerman
Journal: Circulation Research (2024)

Introduction: Fetal heart development is a highly coordinated process directed by complex gene regulatory networks (GRN). Imbalances in such networks can lead to congenital heart defects, a leading cause of morbidity and mortality in children. Many of these defects are related to the improper specification of cardiac progenitor cells to chamber-specific (i.e., atrial, or ventricular) cardiomyocytes, but the GRNs involved in this process are not well characterized. Hypothesis: We hypothesize that cardiomyocyte chamber specification depends on discordant atrial and ventricular regulatory subnetworks within heart field cardiac progenitor cells. Approach: We used CellOracle, a GRN inference software, and publicly available fetal mouse heart single cell RNA and ATAC sequencing data to infer cell type specific GRNs during cardiomyocyte differentiation. Each of the first heart field and two second heart field networks included 4,000 directed interactions and more than 600 genes. We performed a systematic in silico knockdown study with these networks to identify TFs that differentially modulate atrial and ventricular gene expression. Correlations in the downstream responses to TF perturbations were used to extract chamber specification subnetworks. Results: The most central genes within the heart field networks included several previously identified cardiac developmental TFs (Nkx2-5, Mef2c, Tbx5). Perturbations of these heart field GRNs identified 12 TFs that increased ventricular gene expression while also decreasing atrial gene expression (ventricular program), as well as 20 genes with the opposite effect (atrial program). Previous in vitro knockdown studies during iPSC-CM differentiation validated one of the ventricular (Hey2) and two of the atrial programming TF (Nr2f2, Tead2) predictions. Discordant atrial and ventricular regulatory subnetworks were identified, including one network with opposing effects on the expression of Wnt2 by ventricular (repressing) and atrial (activating) TFs. Conclusions: We identified a set of TFs organized within regulatory subnetworks that drive discord specification of ventricular vs. atrial cardiomyocyte gene expression within cardiac progenitor cells in mouse development. These predictions will be validated through in vitro and in vivo studies.
Abstract Mo046: GJA1-20k Restores Connexin-43 Trafficking and β-Catenin Signaling in Myocytes Lacking Desmoplakin
Authors: Mario Maalouf, Vu Nguyen, JENNIFER HUNTER, Daisuke Shimura, Robin Shaw
Journal: Circulation Research (2024)

Background: Arrhythmogenic Cardiomyopathy (ACM) is an insidious hereditary heart disease that results in structural and electrical cardiac abnormalities leading to arrhythmogenesis and heart failure. ACM is characterized by cardiomyocyte loss, decreased cellular coupling, and fibrofatty replacement. The disease arises from mutations in desmosomal genes, such as plakophilin (PKP), desmoglein (DSG), and desmoplakin (DSP). The pathogenesis of this disease is linked to dysfunction at the level of several cellular processes and pathways, including Wnt/β-catenin signaling. Recent evidence has shown that GJA1-20k, a truncated isoform of Connexin-43 (Cx43) generated by internal translation, has a therapeutic role in preserving Cx43 trafficking and cell-cell coupling in ACM of DSG origin. This study aims to investigate the role of GJA1-20k in protecting against ACM of DSP origin by evaluating its effect in cell models on Cx43 trafficking and Wnt/β-catenin signaling. Methods: DSP knockdown was performed on HEK cells and mouse neonatal cardiomyocytes. The role of GJA1-20k was determined using imaging, biochemical, and molecular biology techniques. Results: Protein levels of Cx43 and β-catenin were decreased on Western blot (WB) upon DSP knockdown. These findings were corroborated through imaging wherein the signal intensity for Cx43 at cellular junctions and β-catenin at the membrane was significantly decreased compared to the control group. β-catenin signal intensity was also decreased within the nucleus. Upon administration of GJA1-20k, protein levels of Cx43 were normalized on WB. Moreover, the ratio of phosphorylated β-catenin (inactive) to total β-catenin was decreased. Imaging studies identified a significant increase in Cx43 and β-catenin at the membrane in ACM models treated with GJA1-20k. This was also accompanied by an increase in β-catenin signal intensity within the nucleus. A TOP-flash luciferase assay was performed and revealed a significant increase in β-catenin transcriptional activity in the presence of GJA1-20k despite DSP knockdown. Conclusions: These results suggest that GJA1-20k is able to rescue Cx43 trafficking and recover Wnt/β-catenin signaling in cells and cardiomyocytes lacking DSP. The ability of GJA1-20k to restore dysfunctional genetic pathways involved in arrhythmogenesis and fibro-adipogenesis make it an attractive potential candidate for targeted therapy against ACM.
Abstract Mo065: An Anti-arrhythmic Action and Novel Molecular Mechanisms of Alda-1 in Holiday Heart Syndrome
Authors: Saugat Khanal, Jiajie Yan, Yuanyuan Cao, Nikola Ricchiuti, Alma Nani, Wayne Chen, Michael Fill, Dan Bare, Xun Ai
Journal: Circulation Research (2024)

Introduction: Holiday Heart Syndrome (HHS) is caused by excessive binge alcohol intake. Atrial fibrillation (AF) is the most common arrhythmia in HHS patients. With a worldwide rising trend in heavy alcohol consumption despite significant prevention efforts, effective drugs against alcohol-evoked AF are in urgent need. Methods: We assessed the effect of Alda-1, a cardiac protective agent, on mitigating binge alcohol-evoked AF and alcohol-activated stress kinase JNK2 in 50mM alcohol-exposed (24hr) H9c2 differentiated myocytes and in a well-characterized HHS mouse model (2g/kg ethanol i.p., 4 injections, every other day). Alda-1’s effect on alcohol-evoked RyR2 channel-mediated Ca 2+ waves/sparks &amp; tachycardia/fibrillation (AT/AF) incidence were measured in intact mouse atria. RyR2 channel open probability was assessed in human RyR2 single-channel recordings. Results: We found that Alda-1 significantly reduced atrial arrhythmia inducibility in HHS mouse atria, as evidenced by a decreased incidence of alcohol-evoked AT/AF (0 vs. 0.21 incidences/pacing attempts/animal; n=6, 8). Alda-1 is an agonist of aldehyde dehydrogenase 2 (ALDH2; a key enzyme in alcohol detoxification), which inhibits cellular apoptosis. We found that ALDH2 was increased by 42%±6 in HHS mice compared to controls, and which remained elevated upon Alda-1 treatment (n=6,7,7; p&lt;0.05). HHS hearts showed unchanged apoptotic signaling pathways, suggesting alternative mechanisms in AF genesis. Our lab recently revealed a critical role of activated cardiac stress kinase JNK2 in AF risk. Intriguingly, Alda-1 suppressed alcohol-activated JNK2 by 70%±13 (immunoprecipitated JNK2-specific activity; n=9,9, p&lt;0.001) (but not JNK1, the other cardiac JNK isoform) in cells, while JNK2 inhibition alleviated alcohol-evoked RyR2 channel dysfunction in human RyR2 channels as well as Ca 2+ -triggered atrial arrhythmic activities and AT/AF (0 out of 8; p&lt;0.05) in intact mouse hearts. Conclusion: Alda-1 effectively mitigates binge alcohol-evoked atrial arrhythmogenesis by suppressing JNK2 activity independently of an ALDH2-mediated anti-apoptosis effect. Our findings highlight the potential of Alda-1 as a therapeutic agent for the increasing incidence of alcohol-evoked AF.
Abstract We092: Naltrindole Attenuates Superoxide Release in Polymorphonuclear Leukocytes by a Novel Mechanism devoid of Delta opioid receptor antagonism Related to Reduced Intracellular Calcium Levels
Authors: Mai An Le, Jennifer Dang, Cameron Stinson, Devani Johnson, Logan Clair, James Ramsarran, Desmond Boakye Tanoh, Annam Humayun, Juliet Melnik, Tameka Dean, Qian CHEN, Robert Barsotti, Lindon Young
Journal: Circulation Research (2024)

Introduction: Naltrindole (NTI), known as a delta opioid receptor antagonist, inhibited phorbol 12-myristate 13-acetate (PMA) induced superoxide (SO) release in polymorphonuclear leukocytes (PMNs). PMNs do not express opioid receptors. We propose NTI reduces PMN SO by reducing intracellular calcium (Ca 2+ ). To test this hypothesis, we did experiments using KB-R7943 (KB) as a positive control, known to reduce intracellular Ca 2+ via inhibition of the reverse mode Na + /Ca 2+ exchanger. Naloxone (NX), a broad-spectrum opioid receptor antagonist, was used as a negative control. We predict that NTI will diminish PMA-induced PMN SO release similar to KB, while NX will have no effect, and that there will be no difference in cell viability compared to vehicle controls. Methods: Male Sprague Dawley (SD) rat PMNs (5x10 6 ) were incubated for 15 min at 37 o C in the presence or absence (dH 2 O vehicle control) of NTI (10 - 200 µM), KB (5-20 µM), and NX (100-200 µM). PMN SO release was measured by the change in absorbance at 550 nm over 420 sec via ferricytochrome c reduction after PMA stimulation (100 nM). The cell viability was determined microscopically by 0.2% trypan blue exclusion at the end of PMN SO release assay. Data were analyzed using ANOVA Fisher’s PLSD post-hoc test. Results: NTI significantly decreased PMN SO release at 200 μM (n=10, 0.196±0.06, p&lt;0.05) compared to vehicle control (n=22, 0.731±0.07) or NX 100/200 μM (n=3, 0.593±0.06), and NTI at 100 μM (n=7, 0.461±0.08, p&lt;0.05) versus vehicle control. Likewise, KB significantly decreased PMN SO release at 20 μM (n=7, 0.507±0.07), 10 μM (n=7, 0.552±0.07), and 5 μM (n=5, 0.615±0.11) compared to vehicle control (n=10, 0.908±0.07). Cell viability was statistically similar (80-90±5%) among all study groups. Conclusion: NTI (10-200 μM) and KB (5-20 µM) exhibited concentration-dependent effects in reducing PMN SO release without compromising cell viability. The results suggest that the novel effect of NTI maybe mediated through a reduction in intracellular Ca 2+ and independent of delta opioid receptor antagonism. These results are consistent with the effects of NTI, KB and NX in myocardial ischemia/reperfusion injuries. Future studies will assess the effects of NTI on ROS attenuation in human umbilical vein endothelial cells.
Abstract We065: Sex Differences in Autoimmune Signatures After Myocardial Infarction in Mice
Authors: Alan Mouton, Erin Taylor, Luciano Mendoza, Nikaela Aitken, Jayla Sandifer, Indu Raman, Chengsong Zhu, Jemylle Morato, Alexandre da Silva, Jussara Docarmo, Ana Carolina Omoto, Zhen Wang, Xuan Li, Robert Spitz, John Hall
Journal: Circulation Research (2024)

Introduction: Myocardial infarction (MI) is caused by ischemic injury to the left ventricle (LV), leading to an inflammatory response, scar formation, and loss of LV function. The role of the autoimmune (AI) response during chronic MI, such as B cell activation and autoantibody production, is not well understood. As AI disease is much more prevalent in females, we hypothesized that female mice are more susceptible to MI-induced development of AI signatures. Methods: Permanent MI was induced by left coronary artery ligation in adult male and female C57BL/6J mice for 7, 28, or 56 days. LV function was tracked using echocardiography (VEVO 3100). Cytokines were measured by qPCR. LV IgG and IgM antibody deposition was measured by immunofluorescence. Plasma IgG and IgM were measured by ELISA, and plasma autoantibodies (AABs) (IgG and IgM subclasses) were measured with an autoantigen (AAN) array. Results: In both sexes, MI led to progressive LV hypertrophy, dilation, and wall thinning. MI increased spleen mass in D7, 28, and 56 females, but decreased spleen mass in D28 and 56 males. LV infarct cytokines (IL-1β, IL-6, IL-18, IFN-γ, TNF, CCL2, IL-10) were increased at D7, while IL-6 and IL-18 remained elevated at D28 and 56 to a higher degree in females. Several cytokines in the remote LV were increased in females relative to males, including TNF, IL-6, CCL2, and IL-18. Splenic cytokines were also differentially expressed between sexes, with IL-1β, IL-12a, IL-10, IFN-γ, IL-18, CCL2, and IL-4 increased in females at several time points. Infarct IgG and IgM deposition occurred in both sexes, but to a higher degree in females. Remote IgG and IgM deposition occurred at D56 in both sexes. For plasma AABs, we detected 34 AANs against which IgG AABs were significantly elevated (p&lt;0.05) at D56 in females vs 9 in males, and 30 IgM AABs vs 1 in males. Of note, anti-IL-6 IgM AABs were elevated in D56 females (9.8±0.8-fold), likely due to persistently elevated IL-6 in the female infarct and remote LV vs males. Total levels of plasma IgM were increased only in females at D56 (1.79±0.15-fold). Conclusions: MI promotes development of AI signatures which is exacerbated in females, including increased spleen mass, LV and splenic cytokines, LV infarct and remote IgG and IgM antibody deposition, increased plasma IgG and IgM AABs, and increased total levels of plasma IgM. Targeting the AI response may be a viable option for treating chronic MI outcomes, particularly in females.