tbuckley/cabot-search huggingface dataset:
Abstract Mo009: Systems genetics approach identifies the genetic basis underlying anthracycline-induced cardiotoxicity
Authors: Buyan-Ochir Orgil, Neely Alberson, Akhilesh Bajpai, Morgan Lander, Lu Lu, Jeffrey Towbin, Enkhsaikhan Purevjav
Journal: Circulation Research (2024)

Background: Anthracycline-induced cardiotoxicity (ACT) occurs in 57% of treated cancer patients. Effects of genetic variations to individual susceptibility to ACT is emerging. However, diverse lifestyle and environmental factors combined with small sample sizes in human cohorts remain as limitations to effectively clarify the genetic susceptibility to ACT. This study employed a murine genetic reference population (GRP) of BXD mice derived from crosses between DBA/2J and C57BL/6J strains for mapping of quantitative trait loci (QTLs) associated with doxorubicin (DOX)-induced traits using systems genetics methods. Methods: To model the variability in ACT to DOX, 56 BXD strains (N≥3 mice/sex, 3-4 month-old) were injected intraperitonially once with DOX (20 mg/kg). Survival and body weight (BW) were monitored daily for 10 Days (D). Echocardiography was performed before and on D5 after DOX. Genetic mapping was performed using WebQTL (www.genenetwork.org) and multi-criteria scoring was used for filtering candidate genes associated with DOX-induced traits. Results: Varied body weight loss, proportions and median survival rates were found among DOX-treated BXDs. Parental C57BL/6J strain had 100% survival, while 75% of DBA/2J mice survived on D10. Among BXDs tested, 47 strains had median survival of 6±1 D, with the lowest seen in BXD77 (4 D). Echocardiography revealed abnormal small heart and restrictive dysfunction in BXDs, resembling Grinch syndrome seen in ACT patients. A significant QTL (LRS = 17.11) at 86~94 Mb of Chromosome (Chr) 10 was identified (genome wide P &lt; 0.05). Further filtering identified Gnptab , Slc25a3 , Uhrf1bp1l, and Chpt1 as top candidate genes associated with the survival of DOX-treated BXDs. Mapping of QTLs associated with echocardiography values and weight loss are in a progress. Conclusions: Survival, BW loss, and echocardiography parameters significantly varied among DOX-treated BXDs suggesting an influence of genetic background on expression of those traits. Gnptab , Slc25a3, Uhrf1bp1l, and Chpt1 (Chr 10) are associated with DOX-induced survival traits in BXDs of GRP, suggesting that these genes are involved in modulating ACT severity in humans and require further functional and biological validation.
Abstract Mo003: Concomitant administration of dantrolene is sufficient to protect against doxorubicin-induced cardiomyopathy
Authors: Yoshihide Nakamura, Takeshi Yamamoto, Shigeki Kobayashi, Takeshi Suetomi, Hitoshi Uchinoumi, Masafumi Yano
Journal: Circulation Research (2024)

Background: Doxorubicin (DOX), a commonly used anticancer agent, causes irreversible cardiac dysfunction, which remains a clinical challenge. It has been reported that DOX induces the release of Ca 2+ through ryanodine receptor 2 (RYR2) of the sarcoplasmic reticulum (SR) and increases the Ca 2+ level in the cytoplasm. Objectives: we aimed to investigate whether RYR2 stabilization could suppress DOX-induced cardiomyopathy (DIC) and, if so, the optimal duration of dantrolene treatment (a pharmacological method). Methods: We investigated the relationship between DOX cardiotoxicity and RYR2 stabilization in vivo and in vitro experiments. Results: DOX caused calmodulin dissociation, marked Ca 2+ leakage from RYR2, and increased oxidative stress in isolated cardiomyocytes, which were suppressed by enhancing calmodulin binding affinity of RYR2 and stabilizing its tetramer structure pharmacologically (by dantrolene) or genetically (by RYR2 V3599K mutation). In DIC model mice, cardiac function was impaired, fibrosis and TUNEL-positive cells increased, accompanied by a decrease in GRP78 and increased lipid peroxide levels, which led to endoplasmic reticulum stress and ferroptosis respectively. These cardiac dysfunctions were ameliorated by continuous dantrolene administration or RYR2 V3599K mutation. Interestingly, dantrolene was sufficiently effective for myocardial protection even when terminated 7 days after DOX administration. Conclusions: The short-term concomitant use of dantrolene may be an innovative and clinically feasible DIC preventive strategy. Furthermore, because dantrolene is already safely used clinically as a specific drug for malignant hyperthermia, the results of this study are expected to lead to drug repositioning in the near future.
Abstract Or111: Titin cleavage disrupts sarcomere-adhesion tensional homeostasis triggering cardiomyocyte arrhythmia <i>in vitro</i>
Authors: Maria Rosaria Pricolo, Miguel López-Unzu, Natalia Vicente, Cristina Morales-Lopez, Wendy Perez Franco, Andra C. Dumitru, Francisco Miguel Espinosa Barea, Mateo I. Sanchez, Manuel Oria-Muriel, Roberto Silva-Rojas, Elias Herrero-Galan, Ricardo Garcia-Garcia, Jorge Alegre-Cebollada
Journal: Circulation Research (2024)

The cardiac tissue experiences several forms of mechanical stress, including contraction of cardiomyocytes and forces derived from the stiffness of extracellular matrix (ECM). Preserving homeostatic mechanical forces is crucial for a healthy heart, yet the mechanisms involved are not well-explored. Our study delves into cardiomyocyte responses following the sudden release of mechanical tension across titin, a giant sarcomere protein crucial for setting cardiomyocyte stiffness. Through the expression of virally transduced TEV protease (TEVp) in neonatal mouse cardiomyocytes (NMCMs), we induced the cleavage of mutant titin including the specific TEV protease recognition site (TEVs) within the mechanically active I-band region of the protein. Titin cleavage was validated by 1.8% polyacrylamide SDS-PAGE electrophoresis, revealing a primary band at ~2.2 MDa in TEV-positive NMCMs, corresponding to digested titin fragment A-M. This cleavage, confirmed at 2 days post-infection (dpi) with ~80% efficiency, reached 100% by 5 dpi. Consequently, the Young’s modulus of affected cardiomyocytes dropped by 50%, as determined by Atomic Force Spectroscopy. Sarcomere disarray increased over time, as evidenced by immunofluorescence, yet this effect did not induce cell death or proliferation. Cell viability was confirmed by the fact that affected cardiomyocytes are able to contract spontaneously, although titin cleavage resulted in reduced beating amplitude and induced arrhythmic behavior. Considering this arrhythmogenic situation, we tested cell-cell adhesion through dissociation assays, which revealed significantly reduced intercellular adhesion in affected cardiomyocytes. RNAseq confirmed involvement of pathways related to heart contraction, anchoring junctions, and cell junctions. Specifically, dysregulated genes associated with gap-junction and costamere complexes were observed at 5 dpi. Alterations of adhesion were further confirmed by reductions in connexin 43 and focal adhesion length in immunofluorescence experiments, which also showed mislocalization of important adhesive proteins. In conclusion, titin cleavage in neonatal cardiomyocytes leads to sarcomere disarray, perturbed cell-cell adhesion and arrhythmia. These findings highlight the importance of full mechanical integrity of the titin filament in living cardiomyocytes.
Abstract Mo126: A sex-specific CD4 <sup>+</sup> T cell response limits Coxsackievirus B pathogenesis in mice.
Authors: Christopher Robinson, Aryamav Pattnaik, Adeeba Dhalech, Stephanie Condotta, Caleb Corn, Martin Richer, Laura Snell
Journal: Circulation Research (2024)

Coxsackievirus B3 (CVB3) is an enteric virus that is a primary cause of inflammation of the heart muscle, known as viral myocarditis. Viral myocarditis is a significant cause of heart failure, and nearly 40,000 cases are reported each year. Unfortunately, approximately 5% of CVB3 infections are fatal. Unfortunately, no vaccines or drugs are available for this virus. Interestingly, there is a sex bias in viral myocarditis where men are more susceptible than women. Unfortunately, the underlying basis for the sex bias in infection is incompletely understood. We recently determined that T cells play an essential role in CVB3 clearance using a novel oral inoculation mouse model. Here, we show a sex difference in the CD4 + T cell response to CVB3 that is important in limiting viral pathogenesis. We found that CVB3 induced CD4 + cell expansion in female mice but not in male mice. CVB3 infection also led to the expansion of CD62L lo CD4 + T cells in the mesenteric lymph node and spleen of female but not male mice as early as five days post-inoculation, indicative of activation. Using a recombinant CVB3 virus expressing a model CD4 + T cell epitope, we found that the expansion of CD4 + T cells in females is viral-specific and not due to bystander activation. Finally, the depletion of CD4 + T cells before infection led to enhanced mortality, indicating that CD4 + T cells protect against CVB3 in female mice. We are also currently investigating the impact of CD4 + T cell subtypes, and the role of intestinal T cells play in limiting intestinal CVB3 replication and dissemination. These data demonstrate that CVB3 induces a CD4 + T cell response in female mice and highlight the importance of sex-specific immune responses to viral pathogens.
Abstract Mo019: Angiotensin II Links Cardiovascular Disease With Enhanced Cancer Growth
Authors: Benji van Berlo, Celine Civati, Pierangela Esposito, Gilles De Keulenaer, Pieter-Jan Guns, Vincent Segers
Journal: Circulation Research (2024)

Introduction: It has been demonstrated that CVD promote tumor growth in mouse models of breast, lung, and colon cancer, suggesting a causal relationship between both diseases. Cancer and CVD share several risk factors and pathophysiological mechanisms, e.g. inflammation and oxidative stress, that could explain why patients with CVD are prone to develop cancer. Recent reports also suggest a link between hypertension, hypertrophy and lung cancer. Angiotensin II (ANGII) is a hormone involved in blood pressure regulation, vascular hemostasis and hypertrophy development. Moreover, ANGII is cancerogenic by increasing proliferation of several cancer cell types. Hence, ANGII could be a link in CVD-induced enhancement of cancer growth. Hypothesis: We hypothesized that ANGII treatment, and subsequent hypertension and cardiac hypertrophy, could promote cancer growth. Methods: ANGII (2000 ng.kg -1 .min -1 ; 4w) was administered to 10w old C57B6/J mice using osmotic minipumps. After 4w, pumps were removed and 5*10 5 Lewis lung carcinoma (LLC) cells injected onto the right flank. To study the direct impact of the ANGII peptide on the cancer growth mice were treated with ANGII as mentioned above and LLC cells were injected after 3w to allow concomitant ANGII treatment and cancer growth. A similar experiment was performed by injecting 2*10 5 MC38 colon cancer cells. Tumor growth was monitored for 21d after which the mice were sacrificed. Results are expressed as mean ± SEM. Results: ANGII treatment concomitantly with cancer growth resulted in significantly larger tumors as shown by post-mortem tumor volume (881 ± 111 control vs. 1467 ± 154 mm^3 ANGII, P=0.013). In contrast, no increased tumor growth was observed when ANGII was administered non-concomitant with cancer growth. Interestingly, MC38 tumor growth significantly decreased in the ANGII treated group as portrayed by tumor volume (462 ± 65 control vs. 227 ± 81 mm^3 ANGII). Conclusion: Our data suggest a role for ANGII in CVD-enhanced cancer growth, but also that this effect is not universal, illustrated by a differential effect of ANGII on distinct cancer types. Although further investigation is required to unravel the role of ANGII, screening cancer patients with CVD comorbidities for ANGII involvement might be warranted.
Abstract Or120: CD40 is an immune checkpoint regulator that potentiates myocardial inflammation through activation and expansion of CCR2 <sup>+</sup> macrophages and CD8 T-cells
Authors: Jesus Jimenez, Junedh Amrute, Pan Ma, Xiaoran Wang, Raymond Dai, Kory Lavine
Journal: Circulation Research (2024)

Novel immune checkpoint therapeutics including CD40 agonists have tremendous promise to elicit antitumor responses in patients resistant to current therapies. Conventional immune checkpoint inhibitors (PD-1/PD-L1, CTLA-4 antagonists) are associated with serious adverse cardiac events including life-threatening myocarditis. However, little is known regarding the potential for CD40 agonists to trigger myocardial inflammation or myocarditis. Here, we leveraged genetic mouse models, single cell sequencing, and cell depletion studies to demonstrate that an anti-CD40 agonist antibody reshapes the cardiac immune landscape through activation of CCR2 + macrophages and subsequent recruitment of effector memory CD8 T-cells. We identify a positive feedback loop between CCR2 + macrophages and CD8 T-cells driven by IL12b, TNF, and IFN-γ signaling that promotes myocardial inflammation and show that prior exposure to CD40 agonists sensitizes the heart to secondary insults and accelerates LV remodeling. Collectively, these findings highlight the potential for CD40 agonists to promote myocardial inflammation and potentiate heart failure pathogenesis.
Abstract Mo123: Post-transcriptional Mechanisms of BAG3 Regulation in Ischemia-Reperfusion Injury
Authors: Laura Sherer, Ahmed Zied, Thomas Martin, Michaela Door, Christine Delligatti, Jonathan Kirk
Journal: Circulation Research (2024)

The co-chaperone BAG3 is critical for protein quality control at the cardiac sarcomere. BAG3 binds to Hsp70 and coordinates the assembly of the CASA (chaperone-assisted selective autophagy) complex, thus supporting protein homeostasis and cardiomyocyte contractility. Decreased BAG3 levels are associated with heart disease, whereas BAG3 overexpression rescues ventricular function in animal models of heart failure (HF). Despite BAG3’s potential as a therapeutic target, the mechanisms underlying BAG3 regulation are largely unresolved. Here, we investigate the mechanisms of BAG3 downregulation after stress. We found that BAG3 protein is reduced in human cardiomyopathies compared to non-failing hearts, yet there is an increase in bag3 mRNA transcript, suggesting BAG3’s downregulation in heart disease may be controlled post-transcriptionally. To identify these post-transcriptional pathways, we subjected neonatal rat ventricular myocytes (NRVMs) to prolonged hypoxia-reoxygenation (H/R) stress, which recapitulated the decrease in BAG3 levels observed in human heart disease. Notably, disrupting Hsp70 binding to BAG3 in NRVMs via the drug JG-98 decreased BAG3’s half-life by ~90%, suggesting that Hsp70 protects BAG3 from degradation. Loss of Hsp70-mediated protection could contribute to declining BAG3 levels, so we quantified Hsp70 abundance after H/R stress in NRVMs, finding no significant change. We also found that overexpressing inducible Hsp70 did not rescue BAG3 levels. This data suggests that BAG3 downregulation in H/R stress is not caused by loss of Hsp70 binding/protection. To examine BAG3 regulation in vivo, we subjected wildtype mice to ischemia-reperfusion injury. After 24 hours, we observed a decrease in BAG3 levels in the left ventricle and no significant change in Hsp70 abundance. Interestingly, the decline in full-length BAG3 (85 kDa) was accompanied by an increase in a BAG3 cleavage product at 74 kDa. We analyzed this product via mass spectrometry, discovering that it lacks a third of the WW domain, which is involved in autophagy. In future experiments, BAG3 cleavage will be explored as a potential mechanism of BAG3 loss. Such mechanisms will provide insight into how to maintain BAG3 levels, and thus cardiac function, during stress.
Abstract Tu105: Inhibition of Queuine tRNA-Ribosyltransferase 1 Ameliorates Heaptic Lipogenesis and Atherosclerosis
Authors: Runda Wu, shuning zhang, Yuanji ma, Wei Gao, Jianquan Liao, Xinyu Weng, Yongduan Teng, Lei Zhang, Lili Xu, Ya Su, Wanxin Wang, Yuxiang Dai, Shangyu Hong, Kang Yao, Junbo Ge
Journal: Circulation Research (2024)

Background: Atherosclerosis threatens cardiovascular health, which is featured by abnormal lipid metabolism and chronic inflammation in arterial wall. Queuine tRNA-Ribosyltransferase 1 (QTRT1) , is an enzyme responsible for tRNA modification at the wobble base. Research Questions: It is unclear whether the function of QTRT1 is involved in metabolism of non-cancer cells and tissues, especially lipid metabolism mainly orchestrated by liver. Aims: We aimed to explore the role of QTRT1 deficiency in hyperlipidemia, liver steatosis and atherosclerosis. Methods: Transgenic mice such as Qtrt1fl/flAlb-iCre+/- (Qtrt1LKO), Qtrt1fl/fl(WT), ApoE-/-, and gain of function of PCSK9 by adeno-associated virus gene transfer were used to determine the functional significance of QTRT1 in atherosclerosis. Synthesis, transportation and oxidation of lipids in livers and hepatocytes were examined by quantitative real-time polymerase chain reaction. Moreover, primary hepatocytes with overexpression and downregulation of QTRT1 were followed by RNA sequencing to identify downstream targets. Results: Deficiency of hepatic QTRT1 significantly attenuated hyperlipidemia, liver steatosis and atherosclerotic burden, but increased plaque stability in the aorta of mice. Depletion of QTRT1 markedly downregulated de novo lipogenesis (DNL) without influence on lipoprotein transportation and fatty acid oxidation. Qtrt1LKO mice on a high-carbohydrate diet displayed relatively reduced hyperlipidemia and alleviation of DNL. RNA-seq indicated that odorant binding protein 2A (OBP2A) was upregulated in Qtrt1LKO hepatocytes, which reversed the promotion of DNL by QTRT1 in hepatocytes. Conclusion: Inhibition of QTRT1 in hepatocytes ameliorates hepatic lipogenesis and atherosclerosis in mice. Targeting of QTRT1 is a promising strategy to improve therapeutic effectiveness in both hyperlipidemia and atherosclerosis.
Abstract We090: Antagonistic and Cooperative Dynamics of <i>Irx3</i> and <i>Irx4</i> in Ventricular Compaction
Authors: Rimshah Abid, Yena Oh, Wei Fan Liu, Marwan Bakr, wen-chi yin, YU-QING ZHOU, Xiaoyun Zhang, Riyoun Kim, Rong Mo, Vijitha Puviindran, Matthijs van Eede, Mark Henkelman, Lucile Miquerol, Benoit Bruneau, Chi-Chung Hui, Kyoung-Han Kim
Journal: Circulation Research (2024)

Left ventricular non-compaction cardiomyopathy (LVNC) is a rare heart condition characterized by excessive trabeculae and intertrabecular recesses in the left ventricle of the heart. It is believed to be caused by abnormal trabecular compaction process, which involves trabecular remodelling to form a thick myocardial wall. Embryonic trabeculae consist of bipotent progenitors that differentiate into the ventricular conduction system (VCS) and contractile cardiomyocytes, yet it remains to be further understood how the pathways involved in trabecular cell specifications play a role in the compaction process. Here we present two transcription factors, Iroquois homeobox 3 ( Irx3 ) and Irx4 , playing antagonistic and cooperative roles during trabecular specification and maturation, thereby facilitating proper ventricular compaction. Our single-cell RNA sequencing analysis revealed that the differentiation of trabecular cells into VCS cells was accompanied by increased Irx3 but decreased Irx4 expression. In addition, we found that the loss of Irx4 led to both an increased expression level of Irx3 and an expansion in the number of Irx3 -expressing cells. Conversely, the loss of Irx3 resulted in an upregulation of Irx4 expression within VCS cells. Next, to investigate the functional importance of the antagonistic relationship between Irx3 and Irx4 in trabecular differentiation, we generated Irx3 and Irx4 compound knockout (KO) mice and examined the structure and function of their hearts. Notably, unlike Irx3 KO hearts showing normal ventricular myocardium, Irx4 KO hearts exhibited mild LVNC, and Irx3 and Irx4 double knockouts ( Irx3 /4dKO) hearts displayed severe LVNC. Multiome sequencing of E14.5 ventricles revealed that Irx3 /4dKO ventricles contained an increased number of trabecular cells, expressing higher levels of cell proliferation markers and altered trabecular identity genes, compared to littermate controls. Collectively, our results demonstrate that balanced antagonism between Irx3 and Irx4 is crucial for establishing trabecular identity. This highlights the importance of proper differentiation of trabeculae into the VCS and non-VCS contractile cells during ventricular compaction, thereby preventing noncompaction cardiomyopathy.
Abstract Mo073: Elucidating the Role of Cardiac Radiotherapy on the Sympathetic Nervous System as a Treatment for Ventricular Tachycardia
Authors: Sherwin Ng, Stacey Rentschler
Journal: Circulation Research (2024)

Ventricular tachycardia (VT) is a dangerous arrhythmia that occurs in structurally and electrically heterogenous regions of the diseased heart, leading to sudden cardiac arrest and death if left untreated. One of the main drivers underlying the arrhythmogenic substrate is abnormal remodeling of the autonomic nervous system after cardiac injury, resulting in a heterogenous distribution of sympathetic innervation and subsequent ventricular arrhythmia. In patients with VT refractory to conventional therapy, noninvasive cardiac stereotactic body radiotherapy (SBRT) has emerged as a promising new treatment. Here, we investigated whether cardiac radiotherapy homogenizes the arrhythmogenic substrate through induction of cardiac sympathetic nerve innervation and activity in a closed-chest ischemia reperfusion murine model of ischemic heart failure. Using single nucleus-RNA sequencing, we identified global transcriptomic changes in the left ventricle 6 weeks after 25 Gray (Gy) cardiac X-ray radiation. Notably, these changes included increased expression of neurotrophins such as brain derived neurotrophic factor, a growth factor essential for neuronal survival and development, in irradiated hearts compared to sham controls. Consequently, Western blot and immunofluorescence showed increased expression of the sympathetic neuronal markers tyrosine hydroxylase and neuropeptide Y at the scar border zone of irradiated mice. Similar immunofluorescence results were observed at the irradiated border zone from the explanted heart of a patient previously targeted with 25 Gy compared to a nontargeted remote region within the same heart. These findings suggest a novel role for radiation-induced remodeling of the sympathetic nervous system in the anti-arrhythmic response to SBRT.