tbuckley/cabot-search huggingface dataset:
Abstract Tu081: T-tubule microdomains promote protective mitophagy in failing hearts
Authors: Bradley Richmond, Jing Li, Katsuhiko Funai, Robin Shaw, Tingting Hong
Journal: Circulation Research (2024)

Heart failure (HF) with preserved ejection fraction (HFpEF) represents about 50% of all HF incidence, yet with limited therapeutic options. Although poorly understood, a key pathophysiology of HFpEF includes mitochondrial dysfunction and increased oxidative stress. We recently identified that abnormal remodeling of the cardiomyocyte t-tubule microdomains organized by the scaffolding protein cardiac bridging integrator 1 (cBIN1) contributes to HFpEF progression in db/db mice with type 2 diabetes, which can be rescued by cBIN1 gene therapy. In db/db mice, cBIN1 gene therapy (2x10 12 vg/kg) rescues HFpEF by normalizing t-tubule microdomains. With transmission electron microscopy imaging, here we report that t-tubule cBIN1-microdomains are in close proximity to mitochondria and can correct abnormal mitochondrial accumulation in db/db cardiomyocytes (Figure 1A-B). Oroboros and seahorse analysis indicates that reduced mitochondrial calcium retention, elevated oxidative stress, and impaired oxygen consumption in diabetic cardiomyocytes can be normalized by cBIN1 therapy (Figure 1C-E). Furthermore, proteomics analysis indicates accumulation of mitochondrial proteins in db/db cardiomyocytes can be reversed by the therapy. cBIN1-normalized mitochondrial number, proteomics, and function in db/db cardiomyocytes are associated with activation of LC3 but not changes in PGC1a, indicating increased mitophagy by the therapy. Mechanistic exploration in rat myoblast H9C2 cells indicates that FCCP stress induces mitophagy as evidenced by elevated LC3II/I ratio, which is further accumulated with autophagic flux blockade with chloroquine. Knockdown of BIN1 results in further accumulation of LC3II/I in FCCP-stressed cells (Figure 1F with quantification in the bar graph below), which is abolished by chloroquine. These data indicate that cBIN1 promotes protective mitophagy in diabetic failing hearts, suggesting its therapeutic potential for HFpEF in general.
Abstract Tu063: Acute sleep deprivation induces cardiac remodeling via activation of AT1R/ERK/GSK-3β signaling
Authors: Tao Luo, Haiqiong Liu
Journal: Circulation Research (2024)

Background: Sleep deprivation (SD) has an adverse effect on cardiovascular system. However, whether acute SD contributes to the morphological and functional changes of the heart remains unclear. Approach and Results: The modified multiple platform method (MMPM) was used to establish the SD model in Sprague-Dawley rats. Acute SD significantly enhanced cardiac ejection fraction and fractional shortening in rats as observed by echocardiography. The elevated ratio of heart weight to body weight (HW/BW) and enlarged cross-section area of cardiomyocytes by WGA staining were detected in SD groups (3, 7,10 days). The upregulation of ANP and BNP was also detected by western blotting. Masson-trichrome staining showed significant fibrosis in the SD groups, which was confirmed by western blotting of the fibrosis markers α-SMA and collagen 1. Furthermore, SD increased the level of angiotensin II (Ang II) and angiotensin type 1 receptor (AT1R) in the heart tissue of SD groups accompanied by the activation of the ERK/GSK-3β pathway. Administration of valsartan and benazepril dramatically ameliorated SD-induced cardiac fibrosis and hypertrophy by downregulating Ang II/AT1R and phosphor-ERK/GSK-3β levels. Conclusion: Our results indicated that cardiac remodeling was induced by the acute and short duration of SD, in which the AT1R/ ERK/GSK3β signal pathway was involved. Our study demonstrates a novel complementary phenomenon induced by SD and provides detailed evidence for the risk of SD on the cardiovascular system.
Abstract Mo038: Exploring clinically meaningful change in health-related quality of life and heart problems in a Black population: A Coronary Artery Risk Development in Young Adults Study (CARDIA)
Authors: Isabelle Pierre-Louis, Chengwu Yang, Catarina Kiefe, Sarah Forrester
Journal: Circulation Research (2024)

Background: Health-related quality of life (HRQoL) measures quantify the impact of heart problems on HRQoL changes over time. Previous research has shown Black individuals are more likely to have negative HRQoL changes over time, compared to their White counterparts. However, little research has clarified how sex differences within Black populations, and perceived heart problems play a role in HRQoL changes using the minimal clinically important difference (MCID). Hypothesis: Black women reporting perceived heart problems will have a higher odds of clinically meaningful HRQoL decline over a 15-year period, compared to Black men with perceived heart problems. Methods: We used data from the longitudinal, multicentered study of 853 Black participants attending the years 15, 20, 25, and 30 Coronary Artery Risk Development in Young Adults Study (CARDIA) examinations. Perceived heart problems were self-reported; HRQoL was measured through the 12-Item Short Form Survey consisting of mental (MCS) and physical (PCS) component surveys. For the MCID, we used 0.5 standard deviation of the change score between Year 15 and 30, and then created a binary clinically meaningful decline variable. Mixed effects logistic regression models assessed the impact of race and perceived heart problems on HRQoL changes. Results: At year 30, 66% of women and 34% of men had a clinically meaningful decline in MCS. In PCS, 64% of women and 36% of men had a meaningful decline at year 30. After adjusting for heart problems and sociodemographic factors, Black men have a higher odds of a clinically meaningful decline between years 20 and 25 compared to years 15 and 20 (OR: 1.81, 95% CI: 1.10, 2.99), but this significance was not found in women (OR: 1.00, 95% CI: 0.68, 1.46). We found no significance after adjustment for either men or women in PCS model. Discussion: Previous studies found Black women report lower HRQoL compared to Black men, but few adjust for the impact of heart problems, which are known to impact Black men more frequently. Finding perceived heart problems impact HRQoL changes overtime in Black men, could signify greater issues including lack of care for their heart conditions, and other psychosocial factors. More research may be necessary to understand this association.
Abstract Tu066: Loss of Sigmar1 Aggravated Cardiac Proteotoxicity and Cardiac Dysfunction in Mutant αB-Crystallin Mouse
Authors: Richa Aishwarya, Chowdhury S. Abdullah, Naznin Sultana Remex, Mohammad Bhuiyan, Wayne Orr, Md Shenuarin Bhuiyan
Journal: Circulation Research (2024)

Background: Deposition of misfolded protein aggregates observed in diverse cardiac disease models leads to proteotoxic cardiomyopathy. In earlier studies, we confirmed mutations in α-B-Crystallin, specifically Arg120Gly (CryAB R120G ), develop proteotoxic cardiomyopathy. Cardiomyocyte-specific CryAB R120G overexpression leads to cardiac dysfunction resulting from the accumulation of toxic pre-amyloid oligomers and protein aggregation. In the event of proteotoxic insult, the chaperone proteins function to prevent the accumulation of protein aggregates. One of the multitasking chaperone proteins in the heart is Sigmar1, whose role in proteotoxic cardiomyopathy and protein aggregation remains unknown. Hypothesis: We hypothesize that Sigmar1 plays an essential role in protein aggregate clearance, and the absence of Sigmar1 in CryAB R120G mice aggravates pathological cardiac remodeling. Methods and Result: We measured Sigmar1 expression level in CryAB R120G hearts and found a significant reduction in endogenous Sigmar1 protein and transcript levels in CryAB R120G hearts. Co-immunoprecipitation and yeast-two-hybrid assays demonstrated a direct interaction between Sigmar1 and CryAB. Therefore, we evaluated Sigmar1’s function in the proteotoxic model of heart failure. We ablated Sigmar1 in CryAB R120G , expressing myocytes both in vitro by using Sigmar1 siRNA and in vivo by crossing Sigmar1 knockout with CryAB R120G (CryAB R120G xSigmar1 -/- ) . Both i n vitro and in vivo studies displayed a dramatic increase in protein aggregate size and content in CryAB R120G xSigmar1 -/- heart, assessed by immunostaining and electron microscopy. Echocardiography showed age-dependent aggravation of cardiac contractile dysfunction, and Masson’s Trichrome staining showed increased cardiac fibrosis in the CryAB R120G xSigmar1 -/- hearts compared to CryAB R120G hearts. Conclusion: Overall, we found that Sigmar1 directly interacts with CryAB and plays a vital role in the degradation of protein aggregates where the absence of Sigmar1 causes increased protein aggregate size and content in CryAB R120G mice, leading to aggravated pathology with ventricular dysfunction, increased interstitial fibrosis, and cardiac hypertrophy.
Abstract Mo106: Inhibition of <i>microRNA-200c</i> promotes regeneration of the ischemic injured myocardium through activation of developmental pathways
Authors: Riley Leonard, Mason Sweat, Steve Eliason, Kathy Zimmerman, Ariana Batz, William Kutschke, Robert Weiss, Brad Amendt
Journal: Circulation Research (2024)

Ischemic injury and adverse post-infarction myocardial remodeling are major causes of heart failure worldwide. Strategies designed to offset cell death with cardiomyocyte regeneration have, to date, not translated to routine clinical practice. Mir-200c modulates the transcripts of cardiogenic transcription factors (TFs) Tbx5 , Gata4 , Mef2c to promote myocyte maturation. We hypothesized that inhibition of mir-200c activity would result in postnatal myocyte de-differentiation and replication sufficient to ameliorate post-infarction decompensation after ischemic injury. To test this hypothesis, we preformed left coronary ligation on Wild-Type (WT) and transgenic mice expressing an RNA inhibitor against miR-200c ( PMIS-C ). Echocardiographic left ventricular (LV) ejection fraction (EF) fell from 88.41 ± 1.08% (WT) and 90% ± 1.42% ( PMIS-C ) (p=NS) to 28% ± 11.55% (WT) and 36% ± 9.35% at 1 day post injury (DPI) (p =NS). At 21DPI, LVEF was 27% ± 4.31% (WT) and 64% ± 4.25% ( PMIS-C ) [p ≤ 0.0001]. Post-infarction LV chamber dilation was reversed in PMIS-C mice (1.136 ± 0.19 v 0.67 ± 0.06 p ≤ 0.004 LV Vol/mass). By 9 WPI, PMIS-C heart function within non-significantly levels of sham and function prior to injury. These results indicated that inhibiting miR-200c following ischemic injury can recover cardiac function and prevent LV dilation. Moreover, trichrome stain showed a decrease in fibrosis 3 WPI (WT: 57% ± 17.46 v PMIS-C : 12% ± 3.01 p ≤ 0.001) and 9 WPI. To understand the mechanism causing this phenomenon, we analyzed expression of cardiac progenitor markers. Fold change in expression of TFs Tbx5, Gata4, Mef2c, and Isl1 were increased at 1 and 3 DPI in PMIS-C . At 1 WPI, PMIS-C border zone CMs express markers of a “progenitor-like” cell state seen during cardiogenesis. Conclusions: Inhibiting miR-200c abrogates post-infarction LV remodeling and significantly restores LV systolic function. Ongoing studies are investigating the therapeutic use of PMIS-C through delivery via AAV and nanoparticles.
Abstract Mo107: Age-Related Impairment of Mitochondrial Protein Turnover Exacerbates Pathogenesis of Heart Failure with Preserved Ejection Fraction in Old Mice
Authors: Kamil Kobak, Weronika Zarzycka, Catherine King, Agnieszka Borowik, Frederick Peelor, Michael Kinter, Benjamin Miller, Ying Ann Chiao
Journal: Circulation Research (2024)

Introduction: Age is recognized as a major risk factor for heart failure with preserved ejection fraction (HFpEF), yet the precise role of aging in HFpEF development remains unknown. Disruption of mitochondrial protein turnover affects the quality and quantity of proteins crucial for energy metabolism. Although mitochondrial dysfunction is a key feature of both aging and HFpEF heart, the influence of age-related disturbances in mitochondrial protein turnover on HFpEF pathogenesis remains unclear. Hypothesis: Age-related impairment of mitochondrial protein turnover intensifies proteostatic perturbations induced by hypertensive and metabolic stress (2-hit stress) to exacerbate pathogenesis of cardiometabolic HFpEF. Methods: Young (3 mo.) and old (19 mo.) C57BL/6J male mice were exposed to high-fat diet and L-NAME to induce HFpEF development. Deuterium oxide (D 2 O) labeling coupled with mass spectrometry was used to investigate bulk and individual mitochondrial protein synthesis. The changes in individual mitochondrial protein abundance and protein degradation pathways were also studied. Results: Old mice presented exacerbated HFpEF characteristics compared to young mice, with higher mortality and worsened cardiac and extra-cardiac phenotypes. Regardless of age, mice subjected to 2-hit stress had 24% higher bulk mitochondrial protein synthesis compared to controls. Old control and HFpEF mice showed 17% lower mitochondrial protein synthesis compared to younger counterparts, potentially hindering the replacement of dysfunctional mitochondrial proteins. Aging reduced the synthesis rates of 30 out of 115 proteins synthesized more rapidly with HFpEF, including those involved in mitochondrial metabolism. Despite slower synthesis of numerous mitochondrial proteins with age, the overall abundance of these proteins remained unchanged or elevated compared to young counterparts, indicating impaired protein degradation. We found that aging and 2-hit stress differentially inhibited degradation pathways, including autophagy and the ubiquitin-proteasome system, further impairing protein turnover. Conclusion: Aging impairs mitochondrial protein turnover in cardiometabolic HFpEF and contributes to poorer disease outcomes.
Abstract Tu084: Endothelial Cell STING contributes to Systolic Dysfunction by modulating cardiomyocyte hypertrophy and capillary density in pressure overload-induced heart failure
Authors: Erin Sanders, Noah Wagner, Abraham Bayer, Sasha Smolgovsky, Brandon Theall, mark aronovitz, Robert Blanton, Kuljeet kaur, Pilar Alcaide
Journal: Circulation Research (2024)

Introduction: Cardiomyocyte (CM) hypertrophy, endothelial cell (EC) dysfunction and cardiac inflammation are hallmarks of adverse cardiac remodeling that contribute to heart failure (HF) progression. The “Stimulator of Interferon Genes” (STING) is highly expressed in ECs, the dominant non-CM cell in the heart and contributes to vascular inflammation, yet its role in adverse cardiac remodeling is unknown. We hypothesized that EC STING contributes to systolic dysfunction by modulating adverse remodeling in HF. Methods: Wildtype (WT), global deficient (STING-/-) and inducible EC STING-/- mice or EC STING+/+ littermate controls (Cad5ERTCre2+/–Stingfl/fl treated with Tamoxifen or oil, respectively) were subjected to transverse aortic constriction (TAC) or Sham surgery for 2-8 weeks. Cardiac function was analyzed by echocardiography. Left ventricular (LV) sections were stained with wheat germ agglutinin and isolectin to analyze CM hypertrophy and capillary density. Cardiac leukocytes were analyzed by flow cytometry and gene expression by qPCR. Bulk RNA Sequencing was performed on sorted CD45- CD31+ mouse heart ECs (MHEC) from EC STING+/+ and EC STING-/- after 4 weeks of TAC or sham surgery. ELISA was performed on MHEC supernatant. Results: STING-/- mice did not show a decline in fractional shortening (FS), capillary density or develop LV hypertrophy and had decreased intramyocardial CD45+ leukocytes in response to TAC, compared to WT mice. EC STING-/- mice also showed preserved FS, capillary density, and ameliorated CM hypertrophy over the course of 2, 4 and 8 weeks of TAC, compared to EC STING+/+ mice, despite having similar numbers of myocardial CD45+ leukocytes. RNASeq revealed decreased IL6 transcription, a pro-hypertrophic cytokine, in TAC STING-/- MHECs compared to WT MHECs. Myocardial IL6 gene expression was also reduced in EC STING-/- TAC hearts compared to EC STING+/+. In vitro, STING-/- MHECs had decreased secretion of IL6 protein compared to WT MHECs. Conclusions: Our data demonstrate that EC STING modulates both the EC and cardiac expression of the pro-hypertrophic cytokine IL6, suggesting a mechanism contributing to cardiomyocyte hypertrophy, capillary rarefaction, and systolic dysfunction in response to cardiac pressure overload.
Abstract Mo037: Cardiac-Selective TRPV1 Afferent Ablation in Subacute Myocardial Infarction Ameliorates Adverse Remodeling and Ventricular Arrhythmogenesis
Authors: Kiyoshi Masuyama, Wei-Hsin Chung, Steven Cha, Janaki Patel, Sahil Haridas, Nhi Doan, Devaki Abhyankar, Ronald Challita, Maureen Su, Olujimi Ajijola
Journal: Circulation Research (2024)

Background: Ventricular arrhythmias (VT/VF), the most common cause of sudden death after myocardial infarction (MI), can be ameliorated by cardiac-selective transient receptor potential cation channel subfamily V member 1 (TRPV1) afferent ablation at the time of infarction in animal models. To enable translation to human, it remains unknown whether afferent depletion in the subacute phase of MI will reduce arrhythmias and mitigate long-term structural remodeling. Objectives: To assess the role of cardiac-selective TRPV1 afferent ablation two weeks after MI on the long-term ventricular arrhythmogenesis and adverse structural remodeling. Methods: Yorkshire pigs were randomized to resiniferatoxin (RTX 5.0µg/ml: n=10) or vehicle(n=6) 14days after the left anterior descending artery infarct. Four weeks later, terminal experiments were conducted to evaluate the effect of RTX on cardiac structural and functional remodeling, ventricular arrhythmogenesis, and autonomic reflex function. Results: Cardiac afferent depletion via RTX administration was confirmed by diminished sympathetic response to TRPV1 agonists (bradykinin and capsaicin) and by immunohistochemical analysis of ventricular innervation. Compared to the vehicle treated group, the RTX administration reduced LV dimension (p&lt;0.01), repolarization heterogeneity (p&lt;0.01) and ventricular arrhythmogenesis (program stimulation; p=0.01 and CsCl induced PVCs;p&lt;0.01). In the scar-border zone, myocytolysis and nerve sprouting, which are associated with VT/VF, were attenuated in the RTX group (abnormality score; p=0.01 and nerve sprouting index; p &lt; 0.01). T cell infiltration in dorsal root ganglia was suppressed in the RTX group (p = 0.02). RNA-sequencing of stellate ganglia revealed downregulation of adrenergic genes tyrosine hydroxylase and neuropeptide-Y in the RTX group. Taken together, these results suggest that cardiac afferent ablation in subacute MI alleviates adverse structural remodeling and ventricular arrhythmogenesis by targeting neuroinflammation and reducing stellate ganglion sympathetic overexcitation. Conclusion: Cardiac TRPV1 afferent depletion in subacute MI is a promising disease altering treatment for patients suffering from MI.
Abstract Or109: Regulation of UFM1 modification from ER dynamics to cardiac homeostasis
Authors: Varsha Tandra, Nagendra Singh, Honglin Li, Huabo Su, Jie Li
Journal: Circulation Research (2024)

Cardiovascular disease (CVD) is the leading cause of mortality and morbidity globally. Understanding the molecular mechanism governing CVD has become a major focus in developing new therapeutics. Ubiquitin (Ub) like protein post-translational modifications (PTMs) have been known to play an important role in the normal functioning of the heart. UFM1 (ubiquitin-fold modifier 1) is a novel Ub-like protein that covalently modifies protein substrates via a highly conserved E1 (UBA5)-E2 (UFC1)-E3 (UFL1) enzymatic cascade, named ufmylation. Ufmylation regulates diverse cellular processes and is implicated in various human diseases. However, its importance in the heart is unknown. For the very first time, we have reported dysregulation of ufmylation in dilated cardiomyopathy, hypertrophic human patients, and animal models. It remains unclear whether ufmylation of cardiac proteins is required for heart function and if so, how ufmylation regulates cardiac function. To determine the role of UFM1 modification in cardiomyocytes we have generated cardiac-specific UFM1-knockout (UFM1CKO) mice. The UFM1CKO mice developed dilated cardiomyopathy at resting condition, as indicated by the left ventricle (LV) wall thinning, chamber dilatation, and impaired contractility at 4 months of age, which were further exacerbated by 6 months. It appears that UFM1 modification constrains pathological cardiac remodeling by maintaining ER homeostasis and regulating ER stress response. To test the hypothesis that UFM1 modification, instead of UFM1 itself is required to maintain cardiac function, we replenished UFM1CKO mice with cardiac-specific WT or conjugation-deficient UFM1 via AAV9. By echocardiography, we revealed that, unlike WT UFM1, overexpression of the conjugation-deficient mutant failed to attenuate the cardiac remodeling and dysfunction of the UFM1CKO heart. Interestingly, the conjugation-deficient mutant further exacerbated the cardiac dysfunction of the UFM1CKO mice. Extensive fibrosis and upregulation of ER stress response protein were also noted in conjugation-deficient mutant UFM1 injected UFM1CKO heart. Overall this study indicates that modification of proteins by UFM1 is critical to cardiac function via maintaining ER homeostasis.
Abstract Tu097: Titin cleavage induces loss of myocardial tensional homeostasis driving a rapid TGF-beta-independent fibrotic response
Authors: Miguel Lopez-Unzu, Maria Rosaria Pricolo, Roberto Silva-Rojas, Natalia Vicente, Manuel Gavilan-Herrera, Diana Velazquez-Carreras, Cristina Morales-Lopez, Elias Herrero-Galan, Jorge Alegre-Cebollada
Journal: Circulation Research (2024)

Background: Cardiomyocytes (CMs) are subjected to different types of mechanical loads in the myocardium. Depending on its origin these loads can be classified as extracellular (extracellular matrix-ECM towards CMs), intracellular (exerted by the CM contraction machinery, i.e. the sarcomeres) or intercellular (exerted between CMs). In the myocardium, all these loads are actively maintained in tensional homeostasis (TH). In this context, the study of the sarcomere protein titin is essential, because its I-band region is considered as a hub for mechanotransduction, mostly of intracellular mechanical cues. Research Questions: It has been shown that mechanical disruption of the ECM affects the myocardial TH, leading to morphological changes inside CMs. However, potential alteration of TH resulting from defective mechanics of CM proteins remains unknown due to the lack of specific tools for in vivo studies. Aims: Here we explore the in vivo effects on myocardial TH of an abrupt tensional unloading of titin. Methods: We have experimentally challenged CMs to a tensional unloading by means of titin cleavage in vivo using TEVs-TTN mice. In this model, a cassette with a Tobacco Etch Virus protease (TEVp) recognition sequence has been included in the I-band of titin. Transducing TEVp with adeno-associated virus (AAV), we were able to cleave titin in vivo , ceasing only the mechanical properties of the protein. Samples were analyzed using an array of techniques including histology, immunofluorescence, and bulk and single nuclei RNA sequencing. Results: Our results show that a mosaic expression of TEVp, which does not affect cell viability, cleaving no more than 30% of total titin. However, this leads to a fast fibrotic response (less than six days), characterized by an increase in interstitial collagen and a response from cardiac fibroblasts population. Transcriptional and phospo-SMAD2/3 analysis results suggest that this ECM response occurs without noticeable activation of the TGFβ canonical pathway. Conclusion: Taken together, our results show experimentally for the first time that titin is not only a mechanotransducer of intracellular cues. In fact, mechanical abrogation of the I-band leads to a fast ECM response mediated by cardiac fibroblasts.