tbuckley/cabot-search huggingface dataset:
Abstract Tu035: Targeted Downregulation of MKI67 Mediated by miR-10b-5p Contributes to the Pathogenesis of Kawasaki Vasculitis
Authors: Somy Yoon, Gwang Hyeon Eom
Journal: Circulation Research (2024)

Kawasaki disease is a systemic disorder of enigmatic origin, postulated to stem from an aberrant immune response possibly triggered by infectious agents. This condition prominently risks developing vasculitis, particularly in the coronary arteries, which may lead to aneurysm formation, a grave complication. To shed light on the mechanisms underpinning Kawasaki vasculitis, a thorough investigation was conducted on patients presented at emergency departments. Whole RNA sequencing was utilized to analyze samples from individuals with general infectious diseases, acting as controls, and those diagnosed with Kawasaki disease, forming the experimental group. This approach identified a set of 13 microRNAs (miRNAs) that exhibited increased levels in patients with Kawasaki disease. Following initial findings, the Lactobacillus casei cell wall extract (LCWE)-induced vasculitis animal model, a recognized analog for human Kawasaki vasculitis, was employed to validate the relevance of these miRNAs. Among them, miR-10b-5p was pinpointed as a critical regulator; its inhibition via antagomirs markedly mitigated inflammation near the aortic valve in the LCWE-induced model. To uncover the direct downstream targets of miR-10b-5p relevant to Kawasaki vasculitis, single-cell RNA sequencing was performed. This revealed alterations in human coronary artery endothelial cells (HCAECs) upon miR-10b-5p treatment. Specifically, a subpopulation of HCAECs, initially characterized by proliferation, shifted towards a pro-inflammatory cluster upon miR-10b-5p exposure. This transformation was marked by a decrease in the expression of the proliferation marker, Ki-67 (MKI67), in the pro-inflammatory cluster. Further whole RNA sequencing on HCAECs treated with miR-10b-5p confirmed a significant downregulation of MKI67. Subsequent experiments with siRNA-mediated knockdown of MKI67 resulted in an increase in C-X-C Motif Chemokine Ligand 8 (CXCL8) expression, a pivotal cytokine in inflammation. These findings suggest a novel signaling pathway involving miR-10b-5p, MKI67, and CXCL8, potentially serving as a therapeutic target for Kawasaki vasculitis management in future interventions.
Abstract Tu051: ROR2 Drives Right Ventricular Failure Via Proteostatic Imbalances
Authors: Jonathan Edwards, Genevieve Uy, Hali Hartman, Keita Uchida, Emily Scarborough, Yifan Yang, Eric Barr, Jeff Brandimarto, Li Li, Deborah Eaton, Crystal Conn, Kenneth Bedi, Kenneth Margulies, Benjamin Prosser, Zoltan Arany
Journal: Circulation Research (2024)

Background: No therapies exist to treat right ventricular failure (RVF), in part because RVF molecular drivers have been incompletely studied. We recently identified that the developmentally restricted noncanonical WNT receptor ROR2 is re-expressed in a severity-dependent manner in human RVF. Here we test in mice if, and how, the re-expression of Ror2 causes RVF. Methods/Results: We find in neonatal rat ventricular myocytes (NRVMs) that Ror2 overexpression (Ror2 OE ) both activates protein translation and reduces Hspa1a/b mRNA and Hsp70 protein, resulting in increased protein turnover, fragmented sarcomeres, intercalated disc disruption, reduced cell major axis, impairment of contractile and relaxation kinetics, and ectopy. Ror2 knockdown (Ror2 KD ) results in opposing phenotypes. Hsp70 overexpression or proteasome inhibition rescues many of the Ror2 OE phenotypes, demonstrating their causal involvement. NRVM proteomic analysis indicates that Ror2 OE activates an ERK/p90RSK/Eef2 pathway that is known to regulate translation extension. In vivo, cardiac Ror2 OE in mice causes RV dilation and dysfunction, intercalated disc disruption, reduced Hspa1b (encoding for Hsp70), proteasome activation, and reduced cardiomyocyte ubiquitin staining. The mouse pulmonary artery banding (PAB) model of RVF reveals similar Ror2 induction and proteasome activation. Ror2 KD by AAV9 in PAB reduces RV dilation and improves RV systolic and diastolic function. Finally, in cardiac samples from human RVF, we find evidence for a similar ROR2-responsive proteostatic imbalance with increased proteasome activity and ubiquitin as well as markers of increased ERK and p90RSK. Conclusions: ROR2 is induced in human and mouse RVF, and mechanistic studies in NRVMs and mice show that the induction of ROR2 causes RVF by disrupting the proteostatic balance of translation, folding, and turnover. Knockdown or suppression of ROR2 may serve as a novel RVF therapeutic target.
Abstract Tu052: RPN6-Serine14 Phosphorylation by PKA Protects Against Systolic Overload-Induced Cardiac Remodeling and Heart Failure
Authors: Md Salim Ahammed, Penglong Wu, Liuqing Yang, Jack Sternburg, Huiyun Liang, Faqian Li, Jin liu, Xuejun Wang
Journal: Circulation Research (2024)

The ubiquitin-proteasome system is the main proteolytic pathway for quality control (PQC) and regulatory degradation of proteins in living cells. Systolic overload, as seen in hypertension and aortic stenosis, is a leading cause of heart failure (HF). Proteasome functional insufficiency is implicated in HF caused by systolic overload. Previous studies have established that Ser14-RPN6 phosphorylation (pS14-RPN6) mediates the activation of 26S proteasomes by protein kinase A. However, the pathophysiological significance of pS14-RPN6 in systolic overload remains to be established. We hypothesize that pS14-RPN6 helps maintain proteostasis and protects the heart during systolic overload. We observed a significant increase in myocardial pS14-RPN6 and ubiquitin conjugates in human HF of ischemic or non-ischemic etiologies (p=0.020, p=0.034) and similarly in wild type (WT) mice after 2 weeks of transverse aortic constriction (TAC) (p&lt;0.0001, p=0.001). To investigate the role of pS14-RPN6 in vivo, our lab created Rpn6 S14A (S14A) knock-in mice where Ser14-Rpn6 phosphorylation is blocked. Here we have compared the responses to TAC between WT and S14A mice. We found that TAC-induced increases in myocardial proteasome peptidase activities were significantly attenuated, and accumulation of ubiquitin conjugates exacerbated in S14A mice (p&lt;0.0001; p&lt;0.0005). Serial echocardiography revealed that S14A mice displayed significantly greater left ventricular (LV) end-diastolic posterior wall thickness and LV mass to body weight ratios at 1- and 12-week post-TAC (p=0.024, 0.0003; p=0.005, 0.01), and lower ejection fraction at 12-week post-TAC than WT mice (p=0.035). S14A mice also showed greater heart weight to tibial length (TL) and ventricular weight to TL ratios at 1 and 12-week post-TAC (1-week, p=0.043, 0.039; 12-week, p=0.007, 0.006). Wheat germ agglutinin and picrosirius red staining indicated a greater cardiomyocyte cross-sectional area and cardiac fibrosis in 12-week post-TAC S14A mice vs. WT mice (p&lt;0.0001; p=0.005). These novel findings demonstrate compellingly that myocardial pS14-RPN6 helps maintain proteostasis, curtails cardiac hypertrophy and delays heart failure occurrence during systolic overload
Abstract Tu048: Viscoelastic remodeling of the left ventricular myocardium in myocardial infarction
Authors: Sunder Neelakantan, Rana Raza Mehdi, Qian Xiang, Xiaoxiao Zhang, Peter Vanderslice, Reza Avazmohammadi
Journal: Circulation Research (2024)

Introduction. Myocardial infarction (MI) leads to cardiac myocyte death and the formation of a fibrotic scar in the left ventricular myocardium (LV). LV free wall (LVFW) remodeling in MI is known to significantly alter the biomechanical response of the LV and, in turn, LV function. While changes in the elastic behavior of the LVFW in MI have been reported, changes in the viscoelastic behavior of the LVFW remain understudied. Our objective in this study was to determine the changes in the stress relaxation behavior of the LVFW in MI. Methods. MI was induced in rats via the ligation of the LAD artery, and hearts were harvested for three groups: sham, 2-week (2wk), and 4wk post-MI (n=3 for each group). Prior to sacrifice, echocardiography was performed to estimate ejection fraction (EF). LVFW specimens were harvested and subjected to viscoelastic stress relaxation tests. The specimens were stretched to 15% along the circumferential and longitudinal directions and allowed to relax. The stress was normalized against the peak (initial) stress for each specimen for proper comparison across the groups. Results. The EF at 2wk and 4wk specimens was reduced compared to the sham specimens (Fig. 1A). The 4wk post-MI specimens showed slower stress relaxation compared to that in the sham and 2wk specimens in both directions (Figs. 1B, C). Considering a 2-minute stress relaxation span, the normalized stress in the 4wk specimens was significantly higher than the sham specimens in both directions (Fig. 1D). Conclusions. Our results suggest that the viscoelastic relaxation rate of the LVFW diminishes at late MI timepoints. A larger and more mature scar in the LVFW is expected to contribute to slower relaxation at late MI. Future studies can determine the effect of LVFW viscoelastic remodeling on LV diastolic dysfunction and impaired relaxation in MI.
Abstract Tu061: Pericyte-mediated perivascular fibrosis in the pressure-overloaded heart is dependent on TGF-β signaling and is restrained by ITGB1.
Authors: Izabela Tuleta, Anis Hanna, Silvia Hernandez, Shuaibo Huang, Claudio Humeres, Akihiko Kubota, Harikrishnan Venugopal, Nikolaos Frangogiannis
Journal: Circulation Research (2024)

Background: Pericytes exhibit remarkable phenotypic plasticity and have been implicated in the pathogenesis of fibrosis. Cardiac pericytes are involved in repair and fibrotic remodeling of the infarcted heart; however, their role in the cardiomyopathy induced by pressure overload is not known. We hypothesized that cardiac pericytes may contribute to remodeling of the pressure-overloaded heart by converting into fibroblasts and we examined the molecular signals mediating pericyte activation. Methods and Results: Transverse aortic constriction (TAC) protocols were performed to study the role of pericytes in the pressure-overloaded heart. Using fibroblast:pericyte dual reporter mice and lineage tracing experiments with the inducible NG2 CreER mice (to track pericytes) combined with PDGFRa EGFP reporter mice (to reliably label fibroblasts), we found no pericyte to fibroblast conversion in the pressure-overloaded heart. scRNA-seq demonstrated that pericyte lineage cells do not express fibroblast identity genes after TAC but acquire a fibrogenic phenotype expressing high levels of matricellular genes, growth factors, adhesion molecules and integrins. Bioinformatic analysis identified transforming growth factor (TGF)-b and integrin beta-1 (ITGB1) as important upstream regulators of the transcriptional profile of pericytes after TAC. Pericyte-specific loss of transforming growth factor beta receptor 2 (TGFBR2) attenuated dysfunction and perivascular fibrosis after TAC. In contrast, pericyte-specific ITGB1 loss had deleterious effects increasing mortality, promoting dysfunction, inducing microvascular rarefaction and stimulating a pro-inflammatory and fibrogenic pericyte phenotype. Conclusions: In the pressure-overloaded heart, pericytes acquire a fibrogenic phenotype without converting to fibroblasts. Pericyte-specific activation of TGF-β pathways mediates perivascular myocardial fibrosis after TAC. In contrast, pericyte-specific ITGB1 signaling exerts protective actions, preserving microvascular structure, attenuating inflammation and inhibiting fibrosis.
Abstract Tu039: Intestinal atrophy contributes to low-grade inflammation, cardiac dysfunction and metabolic syndrome-like phenotype in a model of heart failure with preserved ejection fraction.
Authors: Duyen Tran, Liomar Neves, Karina Bonilla, Shamim Chowdhury, Natalie Malczewski, Paola Rosas
Journal: Circulation Research (2024)

Introduction: Heart failure with preserved ejection fraction (HFpEF) comprises half of all HF cases and lacks effective treatment. HFpEF is now seen as a systemic syndrome often linked to comorbidities like hypertension, obesity, and diabetes. These conditions are commonly associated with unhealthy diets rich in fats but lacking in fiber. We explored the effects of a 3-week exposure to excess mineralocorticoids, salt, and high fat diet (HFD) deficient in fiber. We hypothesize that these challenges lead to intestinal atrophy, contributing to low-grade inflammation that promotes the progression of heart failure and metabolic disease. Methods: We used a mix of 1% saline in drinking water and subcutaneous implantation of controlled-release DOCA pellets (0.83 mg/day) alongside a high-fat diet (60% fat) in 8-week-old female and male C57BL6/J mice. Control mice received a standard chow diet and regular water. Results: The challenge resulted in significant reductions in colon mass, colon length, crypt length, and mucus layer thickness compared to the control group. Additionally, elevated levels of C-reactive protein and IL-6 were detected in the plasma. These changes were accompanied by alterations in diastolic function, including decreased peak myocardial relaxation velocity (e'), elevated E/e' ratio, increased E/A ratio, and prolonged isovolumetric relaxation time (IVRT), while the ejection fraction (EF) remained unchanged. Contractility parameters, such as peak myocardial contraction velocity (s'), declined in challenged mice, along with diminished stroke volume (SV). We also found increased organ weight in the liver, spleen, and lungs indicative of organ congestion. Furthermore, signs of metabolic syndrome were identified, including increased body weight, increased adiposity characterized by gonadal and subcutaneous fat accumulation, and dysglycemia (see Data Table). Conclusions: Our data suggests that in this model, heart failure triggers intestinal hypoperfusion, resulting in intestinal atrophy and compromising the integrity of the intestinal lining. Additionally, a diet rich in fat and lacking in fiber alters the gut environment by diminishing mucus production and promoting a closer interaction between the microbiome and host cells. This compromised mucus layer and intestinal barrier facilitates bacterial wall products to move into the circulation, resulting in a pro-inflammatory state that subsequently affects both cardiac function and metabolism.
Abstract Mo117: Investigation of Mechanisms to Modulate Contractility in 13-Lined Ground Squirrels
Authors: Maighdlin Patterson, Po-Jen Chiang, Hannah Carey, Karen Ball, Charles Chung
Journal: Circulation Research (2024)

Introduction: During hibernation, 13-lined ground squirrels cycle between torpor and intermittent bouts of arousal (IBA). Bouts of IBA last 12-48 hours, during which heart rates rise from 2-4 bpm in torpor to 300 bpm during IBA before returning to torpor. Thus, rates of contractility and relaxation and their mechanisms must rapidly change. Phosphorylation of cardiac troponin I (cTnI) at serine 23/24 (pSer23/24) has been shown to decrease calcium sensitivity and increase the rate of myocardial relaxation, enabling faster heart rates. Heat shock protein 27 (HSP27) has been shown to protect contractility by stabilizing troponin. Hypothesis: We hypothesized that cTnI Ser23/24 phosphorylation would be higher in summer and IBA and that HSP27 would be found in higher quantities during torpor and IBA. Methods and Results: Left ventricular tissue (summer, n=8; torpor, n=8; IBA, n=8) was solubilized, separated by SDS-PAGE, and blotted with antibodies for quantification. The pSer23/24 to total troponin ratios were higher in summer compared to torpor (1.22±0.75 vs 0.32±0.19, p=0.003) and IBA (0.57±0.19, p=0.03), but not different between IBA and torpor. No significant season-dependence was observed for the serine 43 cTnI phosphorylation to total troponin ratio (torpor 1.45±0.69, summer 1.05±0.34, IBA 1.15±0.84). No significant season-dependence was observed in HSP27 (normalized to GAPDH) (summer 0.09±0.02, IBA 0.14±0.10, torpor 0.16±0.08). Nor was there a significant season-dependence observed in HSP90 (normalized to GAPDH) (summer 1.57±0.66, IBA 1.13±0.19, torpor 1.22±0.21). Conclusions: None of these mechanisms fully explain the rapid change in contractility observed during the hibernating periods of 13-lined ground squirrels. Other post-translational modifications of troponin or modifiers of HSP activity may modify the reported results. Such regulation may identify new treatments for humans where rapid changes in heart rate or contractility occur.
Abstract Mo113: An Ovary-Intact Postmenopausal HFpEF Animal Model.
Authors: Joshua Strom, Gerrie Farman, Jochen Gohlke, Robbert Van Der Pijl, Hendrikus (Henk) Granzier, Mei Methawasin
Journal: Circulation Research (2024)

Background: The incidence of HFpEF in women significantly escalates following the age of menopause. This trend cannot solely be attributed to chronological aging, as evidenced by the more gradual increase in prevalence among men with HFpEF. This pattern suggests that menopause is a provocative event for HFpEF. However, the underlying mechanisms remain elusive and challenging to investigate in human subjects; moreover, the attempt to create HFpEF in ovariectomized (OVX) mice was unsuccessful. We aim to create an animal model of postmenopausal HFpEF that resembles the characteristics of HFpEF in women with natural menopause. Methods: We use the 4-vinyl cyclohexene dioxide (VCD) to induce “ovary-intact” menopause, combined with the 2hit regimen (HFpEF inducing regimen elicited by high-fat diet and nitric oxide synthase inhibitor) to model postmenopausal HFpEF. VCD gradually causes ovarian failure, providing the perimenopausal transition and preserving residual ovarian stroma, mimicking natural menopause. The HFpEF phenotypes were studied at the in vivo LV by pressure-volume (PV) analysis and at the single cell level by intact cell force measurement. Results: The Female-VCD-2hit model demonstrates diastolic dysfunction at both the LV and the cellular levels. At the LV level, the increase in the end-diastolic pressure-volume relation (EDPVR) stiffness coefficient and LV end-diastolic pressure (LVEDP) indicates a heightened stiffness of the LV chamber and an elevation in LV filling pressure, an HFpEF-like condition. At the cardiomyocyte level, the female-VCD-2hit model exhibits an increase in cellular diastolic stiffness, suggesting that the observed LV diastolic stiffness is derived from the stiffness of the cardiomyocytes. We compared the female-VCD-2hit mice with the OVX mice subjected to the 2hit regimen. The 2hit-OVX model showed a milder form of diastolic dysfunction, observed as a smaller increase in LV diastolic stiffness (EDPVR) and normal LV filling pressure (LVEDP). Conclusions: Female mice, either premenopausal or ovariectomized, are more resistant to the development of HFpEF, unlike their ovary-intact menopausal (VCD-treated) counterparts, which exhibit a vulnerability to HFpEF, making the VCD-2hit model a suitable model to study postmenopausal HFpEF. The LV diastolic dysfunction observed in the 2hit model is attributed to mechanical dysfunction at the cardiomyocyte level.
Abstract Tu032: LRRC8 complex regulates platelet activation and thrombosis
Authors: John Tranter, Ashutosh Kumar, Gavriel Brown, Ryan Mikami, Yonghui Zhao, Nihil Abraham, Tarek Abd El-Aziz, Jehiel Abigail Ajanel Gomez, Litao Xie, Katrina Ashworth, Juan Hong, Haixia Zhang, Tripti Kumari, Adam Balutowski, Alice Liu, David Bark, Vinayak Nair, Nina Lasky, Yongmei Feng, Nathan Stitziel, Daniel Lerner, Robert Campbell, Jorge Di Paola, Jaehyung Cho, Rajan Sah
Journal: Circulation Research (2024)

During activation, platelets undergo both shape and volumetric changes which are mechanical events essential for thrombosis. Volume-Regulated Anion Channels (VRACs) are ubiquitously expressed mechanoresponsive, heterohexameric anion channels comprised of leucine-rich repeat containing protein 8 (LRRC8) A (essential for channel activity) in combination with B, C, D and/or E subunits. In this study, we identify single-nucleotide polymorphisms (SNPs) in three LRRC8 subunits (LRRC8A, C, and D) which are expressed in human platelets and are independently associated with altered mean platelet volume in human genetic studies – implicating the volume-sensing LRRC8 channel complex as a regulator of platelet function in humans. We show that LRRC8A is required for functional LRRC8/VRAC in megakaryocytes (MKs). MK-specific LRRC8A conditional knockout (cKO) mice give rise to LRRC8A-null platelets with larger mean volumes. LRRC8A-null platelets and CRISPR-edited human LRRC8A KO MKs (hiPSC MKs) have reduced agonist-stimulated P-selectin exposure and aIIbb3 integrin activation. LRRC8A-null platelets exhibit impaired adhesion to collagen-coated surfaces and reduced agonist-stimulated aggregation and ATP secretion. Additionally, VRAC in MKs mediate ATP currents which are abolished in LRRC8A-null MKs. In vivo, MK-specific LRRC8A cKO mice have reduced platelet thrombus formation in laser-induced cremaster arteriolar thrombosis, and prolonged occlusion times in FeCl 3 -induced carotid arterial thrombosis, compared to control mice, without affecting tail bleeding times. Mechanistically, platelet LRRC8A mediates swell-induced ATP release to amplify agonist-stimulated calcium influx and platelet aggregation. Small-molecule LRRC8 channel inhibitors largely recapitulate the defects observed in LRRC8A-null platelets. These studies identify the mechanoresponsive LRRC8 channel complex as an ATP release channel in platelets which regulates platelet function and arterial thrombosis, providing a proof-of-concept for a novel anti-thrombotic drug target.