tbuckley/cabot-search huggingface dataset:
Abstract Tu037: Unraveling the Cellular Mechanisms of Cardiogenic Liver Disease
Authors: Arick Park, Adeesh Parvathaneni, Christina Fu, Kathleen Byrnes, Joel Schilling
Journal: Circulation Research (2024)

Background: Right heart failure (RHF) is associated with chronically elevated central venous pressures which can lead to hepatic dysfunction, fibrosis, and ultimately cirrhosis. Despite the prognostic importance of liver disease in RHF little is understood about the cellular and molecular changes that define cardiogenic liver disease. Filling this knowledge gap has the potential to lead to better diagnostic and therapeutic approaches for patients with heart failure and liver dysfunction. Aims: 1) To evaluate the key clinical and pathologic features of cardiogenic liver disease in humans 2) To explore shifts in the cellular landscape in the congested liver using human samples and a mouse model congestive hepatopathy. Methods: We identified 34 patients with heart failure who underwent liver biopsy due to concern for cardiogenic liver disease. These biopsy samples were stained for numerous cellular markers (macrophage subsets, activated stellate cells, endothelial cells, biliary cells) and compared to normal controls. Clinical data was also collected for the included patients. To model cardiogenic liver disease in a mouse we performed partial IVC ligation (pIVCL) to induce liver congestion and then assessed the liver response using flow cytometry, tissue imaging and mRNA analysis. Results: Liver biopsies from patients with cardiogenic liver disease demonstrated increased liver fibrosis, macrophage aggregates, and biliary metaplasia. The severity of biliary metaplasia was closely associated with the extent of liver congestion. Using multi-marker staining the metaplastic cells were found to be of hepatocyte origin. Interestingly, the liver niche containing metaplastic biliary cells was also enriched for recruited macrophages and activated stellate cells. Similar pathologic features were observed in the mouse model of liver congestion. Conclusions: In this study we identified biliary metaplasia and macrophage recruitment as key pathologic features of cardiogenic liver disease. Ongoing investigation of the interplay between macrophages and metaplastic biliary in humans and animal models of congestive hepatopathy may lead to the discovery of novel disease mechanisms and biomarkers for liver dysfunction in heart failure.
Abstract Tu027: Impact of Atherosclerosis-Related Small Cerebral Vessel Damages on Tau Pathology in Atherosclerosis Mouse Model
Authors: Xinyuan Liu, Yanru Wang, Jingyan Han
Journal: Circulation Research (2024)

Background: The linkage between atherosclerosis and vascular dementia, including its ties to Alzheimer’s disease (AD), is well-established. This research explores how small cerebral vessel damages, a less recognized consequence of atherosclerosis, contribute to the development of tau pathology, a key AD hallmark. Methods and Results: Through the ApoE-/- mouse model, we evaluated the impact of hypercholesterolemia and AngII infusion on tau pathology. The regimen included an atherogenic diet for three months and subsequent AngII infusion (1mg/kg/min) for 28 days in three-month-old mice. Key outcomes measured were phosphorylated tau (AT8), cerebral microbleeds, blood component deposition, and oxidative stress markers. Results indicated a synergistic effect of diet and AngII on increasing microbleeds, vascular leakage, and oxidative stress, which coincided with heightened p-tau in affected brain regions. A specific focus on endothelial glutaredoxin-1 (Glrx) deficiency revealed its critical role in moderating these pathological changes, linking endothelial oxidative stress directly with tau pathology. Conclusion: Our research highlights the significant role of small cerebral vessel damage in advancing tau pathology in atherosclerosis, with endothelial oxidative stress as a key mediator. This underscores novel pathways through which vascular health influences AD pathology.
Abstract Tu024: Nitric oxide-dependent Vasodilation in Preeclampsia is impaired due to dysregulated L-arginine pathways and reduced cyclic Guanosine Monophosphate activity
Authors: Julio Valdivia-Silva
Journal: Circulation Research (2024)

To demonstrate the relationship between nitric oxide-dependent vasodilation and the expression of several enzymes from L-arginine pathway such as protein arginine N-methyltransferase-1, arginase-2, and nitric oxide synthase 2 -3, the cyclic guanosine monophosphate expression, and their activity in preeclamptic women, we employed a non-invasive technique to compare endothelial vasomotor function in 60 nonpregnant women, 60 healthy pregnant women, 55 preeclamptic women, and 40 pregnant women with essential hypertension. The concentrations of cGMP were measured in samples of platelets from all groups. RNA and protein expression for the enzymes were examined by reverse transcription-polymerase chain reaction and western blot analysis in umbilical vein endothelial cells that previously were isolated from all groups of women. Nitrite/nitrate in plasma levels were measured spectrophotometrically by Griess reaction. The percentage increase of arterial diameter during reactive hyperemia in nonpregnant women, normal pregnant women, essential hipertensive pregnant women, and preeclamptic women was 7.8 ±2.2%; 16.93 ±2.86%; 9.94 ±1.51% and 6.48 ±1.96% respectively. Vasodilation in preeclampsia and essential hypertensive women was significantly less than that in normal pregnant women. The concentration of platelet cGMP was higher in the normotensive pregnant women than in nonpregnant and essential hypertensive women but did not differ from that in preeclamptic groups. Relative expressions of messenger RNA and protein for eNOS were decreased significantly in preeclamptic and essential hypertension endothelial cells compared with cells from normal pregnancies (P&lt;0.001). Nevertheless, relative messenger RNA for iNOS, Arginase-2, and protein arginine N-methyltransferase-1 was significantly increased in cells from preeclampsia (P&lt;0.001) versus cells from normal pregnancies. Preeclamptic women had significantly higher plasma levels of nitrite/nitrate (49.7 ±7.1 µmol/L) compared with normal pregnant, non-pregnant, and essential hypertensive women (34,2 ±3.1 µmol/L, 29.0 ±8.21 µmol/L, and 17,4 ±2.7 µmol/L respectively). Our results indicate that reduced NO-dependent vasodilation in preeclampsia may be due to the dysregulated expression and activity of enzymes from L-arginine pathway rather than the reduction of cGMP production. Furthermore, increased production of nitrite/nitrate in preeclampsia might be a redirection of NOS 2 and 3 activities to the peroxinitrite production.
Abstract Or101: Phospho-Mimic Mutation in Beta Tubulin Suppresses Arrhythmias and Improves Cardiac Connexin 43 Localization in Duchenne Muscular Dystrophy Mice
Authors: Delong Zhou, Julie Nouet, Elam Mesa, Geovanni Geukgeuzian, Hong Li, Tong Liu, Ghassan Yehia, Peter Romanienko, George Rodney, Xander Wehrens, Paul Lampe, Robert Gourdie, Lai-Hua Xie, Diego Fraidenraich
Journal: Circulation Research (2024)

Duchenne Muscular Dystrophy (DMD) is a severe X-linked neuromuscular disorder, causing progressive muscle degeneration and premature death due to heart and skeletal muscle dysfunction. It is caused by mutations in the dmd gene, leading to the absence of dystrophin, a crucial protein for muscle integrity. There is no cure for DMD. Its associated dystrophic cardiomyopathy is the primary cause of mortality by age 20. Connexin-43 (Cx43) is a gap junction protein responsible for electrical signaling in the heart. Cx43 localizes at the intercalated disc of the cardiomyocyte (CM), forming an intercellular channel with adjacent CMs; In DMD, Cx43 hemichannel remodels to the lateral side of the cardiomyocyte. Our previous research indicated that phospho-mimic Cx43 carrying serine to glutamic acid substitutions at the triplet regulatory site S325, S328, S330 in mdx hearts suppressed Cx43 lateralization and improved cardiac rhythm. The phospho-mimic Cx43 also reduced pathological hyperdensity and transverse directionality of microtubules in mdx cardiomyocytes. Colchicine (Colch) treatment, known to inhibit microtubule polymerization, also improved cardiac rhythm and Cx43 localization in mdx mice. To phenocopy the effect observed with Colch, we generated a mouse model with a beta tubulin mutation at serine 172, which was replaced by glutamic acid (S172E). We found reduced arrhythmias and improved localization of Cx43 in mdx hearts carrying the S172E phospho-mimic mutant tubulin by electrocardiography and immunofluorescent staining, respectively. Moreover, the proteomics data showed that the level of phospho-Cx43 was also upregulated in mdx hearts with S172E tubulin mutation. Further investigation will explore how this mutation impacts protein regulation and electrophysiology, and elucidate its mechanism of action in microtubule polymerization. These studies investigate a regulatory link between microtubule dynamics and localization of Cx43, potentially suggesting a novel therapeutic target for DMD-associated cardiomyopathy.
Abstract Mo115: Aging Heart Failure with Preserved Ejection Fraction is Mediated by Noncoding RNAs
Authors: Sankalpa Chakraborty, Bryce Dickerson, Curren Bounds, Sophia Lemus, Caleb Hickman, Viswanathan Rajagopalan
Journal: Circulation Research (2024)

Introduction: Heart Failure (HF) with preserved ejection fraction (HFpEF) accounts for almost half of the HF population, and the elderly group is at higher risk. HFpEF can be life-threatening and management options are limited. We previously established the importance of thyroid hormones (THs) and inflammation in different cardiovascular disease models. However, the mechanisms of aging HFpEF pathogenesis are unclear. Long-noncoding ribonucleic acids (lncRNAs; &gt;200 nucleotides) outnumber protein-coding counterparts by &gt;4-fold and are clinically important. We hypothesized that lncRNAs act as mediators in aging HFpEF with thyroid dysfunction. Methods: Wild-type control, ZSF1 lean control, and ZSF1 obese (HFpEF) rats at 5-, 13-, ± 20-month (mo) age groups were studied (males and females; maximum 14/group). We employed cardiac ultrasonography, morphometric analyses, lncRNA microarray, real-time qPCR, TH enzyme-linked immune-sorbent, inflammation, and epigenetic assays. Statistical analyses were performed using one-way or two-way ANOVAs and t-tests wherever applicable. Results: Echocardiography showed that ZSF1 obese rats (HFpEF) had unaffected fractional shortening compared to both controls (51% to 53.8%; p&gt;0.05). Morphometrics showed significant increases in weights of the body, kidney, liver, and/or left ventricle in the ZSF1 groups (worse in obese) at 5-, 13-, ± 20-mo time-points (p&lt;0.05). Serum TH levels were significantly decreased at 5- and/or 13-mo in HFpEF vs. controls (p&lt;0.05). LncRNA microarray showed several significant differentially expressed lncRNAs and mRNAs in HFpEF compared to controls. In addition, key lncRNAs were validated via real-time qPCR at 5-, 13-, ± 20-mo time-points (p&lt;0.05; fold change ±1.5). Significantly enriched pathways including inflammation were also identified using GO and KEGG analyses. Correspondingly, inflammatory cytokines were significantly altered in HFpEF both in serum and cardiac tissues at 5- and 13-mo (p&lt;0.05). Conclusions: These results indicate that lncRNAs play important roles in HFpEF associated with hypothyroidism and inflammation. These studies serve as significant steps in the identification of key targets in HFpEF offering potentially valuable translational opportunities.
Abstract Tu030: High-density Lipoprotein Induces Arginase I Expression in M1 Macrophages
Authors: Wei-Ling Lin, Shuan-Hui Wu, Yu-En Hung
Journal: Circulation Research (2024)

Macrophages play a central role in atherosclerosis. While M1 macrophages contribute to atherosclerosis progression, M2 macrophages are primarily associated with its regression. Increasing levels of high-density lipoprotein (HDL) in mice with atherosclerosis have been demonstrated to cause plaque regression; however, the underlying mechanism is poorly characterized. Our objective is to examine whether HDL would ameliorate plaque formation by counteracting M1 phenotypes. Monocyte-derived macrophages were polarized into M1 (interferon-γ plus lipopolysaccharide) and M2 (interleukin-4 plus interleukin-13), followed by treatment with HDL. The phenotype changes, including gene expression and cytokine secretion, in M1 and M2 under HDL treatment were assessed. The results demonstrated that HDL induces the expression of arginase 1 (Arg1), the anti-inflammatory M2 marker facilitating tissue repair, exclusively in M1 macrophages. Reciprocal downregulation of inducible nitric oxide synthase and tumor necrosis factor-α was observed, suggesting a reduction of inflammation. Interleukin-6, the downstream cytokine triggered by Arg1, was elevated upon HDL treatment. Gene expression of L-arginine transporters, SLC7A1, was dominantly expressed in M1 macrophages, but its levels were not altered by HDL. Moreover, we analyzed the concentration of L-arginine, a substrate of Arg1, in human serum and revealed a positive correlation with low-density lipoprotein and total cholesterol levels, but no significant relation to HDL. Subcellular groups analysis in ascending aorta from mice identified that Arg1 expression was higher in normal diet-fed than in high-fat diet-fed. The present study demonstrated that HDL reduces the inflammatory phenotypes of M1 macrophages by increasing Arg1 expression, which may contribute to atherosclerosis plaque regression.
Abstract Tu069: Development of a Novel Biallelic, Haploinsufficient Mouse Model of <i>MYBPC3</i> Related Hypertrophic Cardiomyopathy
Authors: Joshua Meisner, Abbey Bullard, Sabrina Friedline, Olivia Rechsteiner, Michael Previs, Adam Helms
Journal: Circulation Research (2024)

Background: No current animal models re-capitulate MyBP-c haploinsufficiency and hypertrophic cardiomyopathy (HCM) observed in patients with heterozygous MYBPC3 truncating variants, the most common genetic cause of HCM. We recently identified a hypomorphic (partial) loss of function MYBPC3 variant that increases disease severity in HCM patients when combined with an MYBPC3 truncating variant. Hypothesis: Additive effects from a hypomorphic loss of function MYBPC3 variant observed in human HCM will result in MyBP-c protein haploinsufficiency and HCM in a biallelic murine model. Methods: To test MYBPC3 dose effects, induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) were first derived from an HCM patient with biallelic hypomorphic and complete loss of function variants in MYBPC3 . We then generated Mybpc3 knock out (Mybpc3 KO ) and hypomorphic knock in (Mybpc3 KI ) alleles in mice. Control (Mybpc3 +/+ ), monoallelic, and biallelic mice and iPSC-CMs were characterized with morphometric measurements, echocardiography, mass spectroscopy, and RNA sequencing. Results: Biallelic iPSC-CMs demonstrated haploinsufficiency not present in heterozygous models through dose reduction in MYBPC3 protein (Fig 1A). Similarly, biallelic Mybpc3 KI/KO mice had a reduction in Mybpc3 transcripts (62±3%, p&lt;0.001) with 43±11%% reduction in MyBP-c protein (Fig 1B) and cardiac hypertrophy (10±5% increase in heart mass, p=0.002, Fig 1C). Conclusions: Graded reduction in Mybpc3 transcripts in a biallelic mouse model results in MyBP-c haploinsufficiency similar to that observed in HCM patients. Corresponding hypertrophy establishes this approach as a clinically relevant, novel model of MYBPC3 HCM.
Abstract Tu064: Abnormal Calcium Regulation Leads to Pathological Cardiac Hypertrophy During Pregnancy in the GSNOR-Deficient Mouse Model of Preeclampsia
Authors: Raul Dulce, Wayne Balkan, Joshua Hare, Shathiyah Kulandavelu
Journal: Circulation Research (2024)

Introduction: Preeclampsia (PE), a leading cause of maternal mortality, is linked to cardiac hypertrophy and impaired relaxation, predisposing the mother to an increased risk of cardiovascular (CV) injury during pregnancy. Mice lacking S-nitrosoglutathione reductase (GSNOR –/– mice) exhibit all the clinical features of PE. Calcium regulation plays an important role in cardiac relaxation and hypertrophy, but whether alterations in calcium handling contribute to the impairment in these PE mice is unknown. Hypothesis: Cardiac hypertrophy and impaired relaxation in pregnant GSNOR –/– mice may be due in part to altered Ca 2+ handling mechanisms. Methods: Pregnant control (WT [C57B6]) and GSNOR –/– mice were examined at non-pregnant (NP) and late pregnancy (17.5 dpc). Cardiomyocytes (CMs) were isolated (N=3-4 mice/group; n=8-24 CMs/heart) and assessed for intracellular Ca 2+ and sarcomere shortening using IonOptix. Ca 2+ decay and sarcomere relaxation rates were recorded. Ventricular tissue homogenates were assessed for Ca 2+ handling and sarcomere-associated protein expression and post-translational modifications by Western Blot. Results: At late pregnancy, the CMs of GSNOR –/– mothers were significantly wider and systolic and diastolic Ca 2+ levels were elevated as compared to WT. At 17.5 dpc, expression of Ca 2+ handling proteins, RyR2, L-TCC and NCX1 were increased, and phosphorylation of RyR2 and L-TCC were increased in the GSNOR –/– mothers as compared to WT. The Ca 2+ decay rate improved in CMs from pregnant versus NP WT CMs but not in GSNOR –/– CMs. PLB phosphorylation at Thr-17 was augmented in pregnant WT hearts, while phosphorylation at Ser-16 was reduced in pregnant GSNOR –/– . Sarcomere relaxation parameters and sarcomere resting length were improved in CMs from pregnant WT mice but were impaired in pregnant versus NP GSNOR –/– mice in association with increased expression of MyBPC in pregnant GSNOR –/– . Conclusion: The PE-related cardiac hypertrophy and impaired relaxation at late pregnancy in GSNOR –/– mice were associated with elevated cytosolic Ca 2+ levels, altered expression and post-translational modifications of Ca 2+ handling and sarcomeric proteins, which may predispose these mice to higher CV injury during pregnancy.
Abstract Or102: Macrophage-Mediated Interleukin-6 Signaling Drives Ryanodine Receptor-2 Calcium Leak in Postoperative Atrial Fibrillation
Authors: Joshua Keefe, Yuriana Aguilar, Jose Alberto Navarro-Garcia, Amelie Paasche, Issam Abu-Taha, Marcel Tekook, Florian Bruns, Markus Kamler, Ying Shen, Dobromir Dobrev, Xander Wehrens
Journal: Circulation Research (2024)

Postoperative atrial fibrillation (poAF) is self-limited AF that occurs days after cardiac surgery in one-third of patients. The degree of perioperative increase in systemic inflammation, particularly involving interleukin (IL)-6, correlates with poAF risk. However, no studies to-date have identified the cell types involved nor mechanistically linked IL-6 signaling to fundamental arrhythmia mechanisms. To study poAF, we developed a mouse model consisting of atrial pericardiectomy and transient aortic cross-clamping followed by intracardiac burst pacing on postoperative day three to assess poAF inducibility. Single-cell RNA sequencing of atrial non-myocytes revealed macrophages to be the most prominently altered atrial cell type – increased 2.4-fold ( P &lt;0.001) in mice with versus without poAF. Pseudotime trajectory analyses revealed IL-6 to be the top cytokine altered in macrophages, which we confirmed by western blot demonstrating a 1.7-fold ( P =0.012) increase in atrial IL-6 protein in mice with versus without poAF. Indeed, both macrophage depletion and conditional knockout of IL-6Ra in macrophages decreased poAF inducibility by 5.2-fold ( P =0.048) and 5.5-fold ( P =0.027), respectively. Downstream inhibition using an FDA-approved STAT3 inhibitor also rescued poAF (6.0-fold decrease, P =0.022). At the single atrial cardiomyocyte (ACM) level, IL-6 challenge led to a 6.3-fold ( P &lt;0.001) increase in calcium (Ca 2+ ) spark frequency after normalization to sarcoplasmic reticulum Ca 2+ load, indicative of ryanodine receptor-2 (RyR2) dysfunction. Indeed, RyR2 phosphorylation at Ser2814, the target of Ca 2+ /calmodulin-dependent protein kinase II (CaMKII), was increased in the atria of mice with poAF, and CaMKII inhibition was sufficient to rescue arrhythmogenic Ca 2+ sparks in ACMs from mice with poAF. We corroborated our findings in human ACMs and atrial tissue to demonstrate translational relevance. Taken together, we use an integrated approach incorporating mouse and human biochemical, functional, and single-cell sequencing data to demonstrate that infiltrating atrial macrophages, specifically IL-6Ra from macrophages, are fundamentally required for poAF development ( Fig. 1 ). Molecularly, enhanced atrial IL-6 signaling led to arrhythmogenic RyR2 dysfunction through CaMKII. Our findings portend therapeutic utility by providing mechanistic evidence that targeting the IL-6 axis may be used for poAF prevention and treatment in a clinically amenable timeframe.
Abstract Mo114: Assessing Diastolic Performance in Working Myocardial Slices from ZSF1 Rats
Authors: Emmaleigh Hancock, Alexa Price, Raihan Kabir, Shaina Weingart, Brad Palmer, Matthew Caporizzo
Journal: Circulation Research (2024)

Diastolic dysfunction is a prevalent and therapeutically intractable feature of heart failure which arises from increased ventricular compliance and impaired relaxation. Properly assessing diastolic performance is challenging because it requires simultaneous in-vivo measurement of ventricular pressure and volume. Furthermore, identifying diastolic dysfunction may require the simultaneous application of a stress such as physical exertion. Herein, we demonstrate a preparation that recapitulates the complexity of diastole in working myocardial slices: a force-feedback system providing precision control of pacing frequency, preload, afterload, and a tunable stretch at the end of diastole that mimics late filling driven by atrial systole. We assess the diastolic performance (isovolumic relaxation, early and late filling characteristics) in working myocardial slices from a known model of diastolic dysfunction, ZSF1 Obese rats and their Lean control. We find that parameters relating to myocardial performance such as slice work, stroke length, and twitch force are the same between Lean and Obese animals but parameters of diastolic performance are altered in the Obese rats. Specifically, we observe a decreased separation between peak early and late filling with a reduced diastolic filling interval at the same pacing frequency while we do not observe a difference in isovolumic relaxation time. Taken together, these results indicate that while the work output of myocardium is preserved in ZSF1 Obese rats, a reduction in available filling time and early filling efficiency may indicate a reduced capacity maintain output at higher heart rates.