bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 250: Haploinsufficiency of Muscle-Enriched A-Type Lamin Interacting Protein (MLIP) Manifests as Enlarged Dilated Hearts
Authors: Burgon Patrick , Lockwood Julia , Wells Glenn , Blais Alexandre 
Published: July 2021

Approximately 116 unique mutations in the lamin A/C gene have been described to date that are associated with dilated cardiomyopathy. We recently reported the discovery of MLIP through its interaction with lamin A/C. MLIP is expressed ubiquitously and most abundantly in heart, skeletal and smooth muscle of amniotes (mammals, reptiles and birds) and has no paralogous homologue suggesting no functional redundancy. The MLIP gene encodes at least seven, alternatively spliced, LMNA-interacting factors that possess several structural motifs not found in any other protein. The MLIP isoforms pattern of expression differs between each of the tissues with heart being the most heterogeneous. Down-regulation of lamin A/C expression by shRNA results in the up-regulation and mis-localization of MLIP. In addition to interacting and co-localizing with lamin A/C we also demonstrated that MLIP localizes to micro-domains in the nucleus with promyelocytic leukemia protein (PML) in close proximity to chromatin. MLIP's biological function still remains elusive.
Eight week old hemizygous MLIP null mice develop enlarged hearts with a significant increase in heart to body weights (MLIP+/+ 5.62mg/g vs MLIP+/- 10.73mg/g, p<0.0001 n=7) with an overall 30% increase in the anterior-posterior ventricle length of MLIP hearts while maintaining a normal body weight (Figure). Echocardiographic analysis of MLIP+/- mice revealed that their hearts as having a significant (p3.93mm with a significant (p=0.011, n=12) reduction of left ventricular fractional shorting (LVFS) 31% when compare to littermate controls. Histological analysis of the hearts showed no overt phenotype other than an overall increase in the size of the MLIP+/- hearts. The cellular source for the increase in heart size and mass remains to be determined if it is the product of an increase in the number of cardiomyocytes due to aberrant hyperplasia or an increase in cardiomyocyte size through cellular hypertrophy.
In conclusion, MLIP is a newly discovered lamin interacting protein that may serve as a transcriptional regulator that impact genes involved in heart development, growth and function and provides a new signaling paradigm.
Abstract 251: Development of a Transgenic Goat Model with Cardiac-Specific Overexpression of Transforming Growth Factor-β1 to Study the Relationship Between Atrial Fibrosis and Atrial Fibrillation
Authors: Polejaeva Irina A , Hall Justin , Meng Qinggang , Zhou Xinchang , Sessions Benjamin R , Panter Kip , Stott Rusty , Rutigliano Heloisa M , Davies Christopher J , Wang Zhongde , Ranjan Ravi , Dosdall Derek , MacLeod Rob , Marrouche Nassir , White Kenneth L 
Published: July 2021

Studies on patients, large animal models and transgenic mouse models have shown a strong association of atrial fibrosis with atrial fibrillation (AF). However, it is unclear whether there is a causal relationship between atrial fibrosis and AF or whether these events appear as a result of independent pathological changes in the heart. We are testing the hypothesis that goats that overexpress TGF-β1 (transforming growth factor beta1) specifically in cardiac myocytes will develop atrial fibrosis that in turn will lead to AF. Many aspects of AF-related remodeling have been studied comprehensively in goat models. However, these AF models are typically mechanically induced (eg, the rapid atrial pacing model). This unique transgenic goat model has the potential to offer insights into the role of fibrosis in AF initiation and progression without the confounding effects of mechanical AF induction.
Somatic cell nuclear transfer (SCNT or cloning) was used to produce TGF-β1 transgenic pregnancies. First, pcDNA3.1DV5-MHC-TGF-β1cys33ser vector was constructed by subcloning the MHC-TGF-β1 fragment from the plasmid pUC-BM20-MHC-TGF-β1 into the pcDNA3.1D V5 vector. The NeonTM transfection system was used to electroporate primary goat fetal fibroblasts. After two weeks of G418 selection, the resulting G418 resistant colonies were screened by PCR to confirm transgene integration into goat genomic DNA. PCR positive cells were used for SCNT. Cloned embryos (n=264) were cultured for 12-60 h in vitro and then transferred into synchronized recipient females (n=15). Confirmation of pregnancy was done by ultrasonography on day 30 post-transfer. At the time of this abstract submission, 40% (6/15) of recipients were confirmed to be pregnant as determined by the presence of a heartbeat. The range for the stage of gestation is between day-60 and day-120. The first delivery date is April 28, 2012. Several reports documented no pregnancy losses after 30 days of gestation in goats. Therefore, we expect that most if not all of these pregnancies will result in delivery of live offspring. To our knowledge, this will be the first transgenic goat model generated for cardiovascular research.
Abstract 272: RBPJ Controls the Angiogenic Response of Mouse Adult Cardiomyocytes
Authors: Diaz Trelles Ramon , Scimia Maria Cecilia , Ruiz Lozano Pilar , Mercola Mark 
Published: July 2021

Cardiac microvasculature density is critical for a correct cardiac function under normal and stress conditions. We found that the transcription factor RBPJ, downstream of the Notch signalling, can regulate angiogenic factors gene expression by repression (normal homeostasis) or activation (stress) and also by modulating the hypoxia induced angiogenic response.
Accordingly, in normal conditions cardiomyocyte specific RBPJ KO adult mice hearts show a denser microvasculature. Isolated mouse adult cardiomyocytes show increased gene expression and promoter hyperacetylation and hypermethylation of angiogenic factors and Notch target genes (like HES1).
Stress induced by myocardial infarction (MI) or cardiac overload (TAC) activate an angiogenic response to compensate the increased oxygen demand. Notch pathway is activated and RBPJ accumulated in the nucleus after MI and TAC. After TAC, deletion of RBPJ did not block hypertrophy induction, but prevented the increase in angiogenic factor production and microvessel density that normally occurs in response to increased workload. Remarkably, the KO preserved cardiac function and reduced cell death and fibrosis after myocardial infarction. Thus, RBPJ acts in cardiomyocytes as a master factor orchestrating homeostatic and disease-induced angiogenesis, and modulating RBPJ protects against ischemic injury.
Abstract 292: Isoform-Specific Expression of Estrogen-Related Receptors Regulates Cardiomyocyte Metabolic Adaptation to Oxidative Stress
Authors: Cribben Kathryn , McDermott Paul 
Published: July 2021

In the ischemic heart, metabolic adaptation of cardiomyocytes exposed to prolonged hypoxia is critical to sustain myocardial energy production. Metabolic gene expression is regulated by Estrogen-Related Receptor (ERR) transcription factors and Peroxisome Proliferator-Activated Receptor γ Coactivator-1 (PGC-1) co-activators. ERRs do not require ligand to achieve an active conformation and regulate an array of target genes involved in myocardial energy metabolism. These studies aim to determine the regulatory mechanisms governing expression of ERR isoforms (ERRα and ERRβ) in cardiomyocytes undergoing oxidative stress. We hypothesize that metabolic energy production in myocardium initially adapts to hypoxia by inducing transient ERRβ expression, and maintains this compensatory expression through induction of sustained ERRα expression.
Adult feline cardiomyocytes in primary culture were electrically stimulated to contract continuously at 1 Hz under normoxia (21% [O2]), hypoxia (0.5% [O2]), or hypoxia followed by reoxygenation. Expression of ERR, PGC-1 and target genes was measured by QRT-PCR (n≥5). QRT-PCR arrays were used to screen for prospective target genes.
In response to 24 hours of hypoxia, mRNA levels increased for ERRα (3-fold by 24 hours), ERRβ (11-fold by 12 hours), PGC-1α (16-fold by 24 hours) and PGC-1β (8-fold by 24 hours). Subsequent reoxygenation for 24 hours decreased ERRβ, PGC-1α and PGC-1β mRNA levels to that of normoxia controls. However, reoxygenation did not markedly decrease (∼25%; 0.7 of 3.0-fold) ERRα mRNA levels. Cytochrome C Oxidase Subunit VIc (Cox6c) and Fatty Acid Binding Protein 3 (Fabp3) were identified as potential ERRα target genes in adult cardiomyocytes based on correlation of expression. Moreover, hypoxia-induced increases in Cox6c and Fabp3 mRNA levels were partially blocked by treatment with XCT-790, an inhibitor of ERRα activity.
We conclude that hypoxia and subsequent reoxygenation elicit isoform-specific changes in ERR and PGC-1 mRNA expression in adult cardiomyocytes. This observed regulation of expression for ERR isoforms and their target genes may play a critical role in metabolic adaptation to oxidative stress.
Abstract 331: HCN Overexpression in Failing Heart Possibly Contributes to Ventricular Arrhythmias
Authors: Kuwabara Yoshihiro , Kuwabara Koichiro , Takano Makoto , Kinoshita Hideyuki , Nakagawa Yasuaki , Usami Satoru , Nakao Kazuhiro , Minami Takeya , Yamada Yuko , Yamada Chinatsu , Shibata Junko , Nishikimi Toshio , Yasuno Shinji , Ueshima Kenji , Nakao Kazuwa 
Published: July 2021

Accumulating evidence suggests increased ventricular expression of hyperpolarization-activated cation channels (HCNs) in hypertrophied and failing hearts contributes to the induction of arrhythmias. In this study, we addressed the capacity of HCNs blockade to prevent lethal arrhythmias associated with heart failure.
Transgenic mice expressing a dominant-negative mutant of neuron-restrictive silencer factor in a cardiac-specific manner (dnNRSF-Tg) exhibited dilated cardiomyopathy and sudden arrythmic death with an increase in ventricular HCNs expression, which are potentially responsible for the observed lethal arrhythmias. Ivabradine (Iva), a specific HCN channel inhibitor, significantly improved the survival among dnNRSF-Tg mice. Though echocardiographic, hemodynamic, and histological analyses showed no significant difference between Iva and control, ECG telemetric monitoring showed the significant reduction of arrhythmias in dnNRSF-Tg mice treated with Iva (VT; Iva 19/h, control 92/h ; p<0.05), suggesting that Iva improved the survival by preventing lethal arrhythmias.
We also found that the transgenic mice overexpressing HCN2 specifically in the heart (HCN2-Tg) are susceptible to ventricular arrhythmias induced by chronic isoproterenol infusion. In isolated ventricular myocytes from HCN2-Tg, but not in those from wild type mice, isoproterenol induced abnormal spontaneous action potentials, which were suppressed with Iva.
Our findings suggest that increased ventricular expression of HCN channels possibly contributes to the ventricular arrhythmias, and HCN channels blockade may represent a new and effective means of preventing sudden arrhythmic death in patients with heart failure.
Abstract 355: Systems Epigenomics of Chromatin Structure in the Heart
Authors: Franklin Sarah , Chen Haodong , Karbassi Elaheh , Monte Emma , Vondriska Thomas M 
Published: July 2021

Except during metaphase, endogenous chromatin structure is unknown. DNA - invariant between cells - and the cell type-specific modifiers of the genome establish chromatin structural features, both local (e.g. at the scale of individual nucleosomes) and global (e.g. chromosomal territories). A fundamental question is how these cell type-specific modifiers, including DNA modification, non-coding RNAs, and proteins, establish the chromatin environment conducive to gene expression for the correct cell type: in cardiac muscle, how is the genome structurally poised to confer cardiac (and not, say, renal) transcriptomes and proteomes, and what physical reprogramming events occur during disease?
To address these questions, we are conducting a systems analysis of the epigenetic features of the healthy and diseased heart. In adult mice, we have used quantitative mass spectrometry to dissect distinct fractions of the nucleus and reveal the itineraries of chromatin structural proteins, enzymatic nucleosome remodelers, histone molecules and histone post-translational modifications. These studies have revealed rules for global reprogramming of gene expression, which involve altered abundance of non-histone chromatin structural proteins, a shift from hetero- towards euchromatic post-translational marks and a decreased linker to core histone ratio in heart failure. Furthermore, interrogation of genome-wide binding patterns of known cardiac transcription factors within the genes that encode proteins operative in cardiac genomic structure reveals hierarchical relationships between these protein, transcript and gene networks. Complementary investigations in isolated myocytes are characterizing the global rearrangement of chromatin following hypertrophic agonist treatment using conventional and super-resolution microscopy to directly visualize the chromatin backbone. Lastly, a combination of multiple genomic scale sequencing studies have revealed regions under control of specific chromatin structural proteins. Together, these studies aim to address the basic question of how global chromatin structure is maintained in cardiac myocytes and how diseases like heart failure result from deranged chromatin structure on a genomic scale.
Abstract 362: Proteomic Analysis of Low Oxygen Tension-Induced Secretome of Adipose Tissue-Derived Stem Cells
Authors: Bosnjak Zeljko , Wakim Bassam , Yan Yasheng , Canfield Scott , Kikuchi Chika , Bai Xiaowen 
Published: July 2021

Growing evidence from animal studies shows that adipose tissue-derived stem cells (ASCs) improve cardiac function of infarcted hearts. It is commonly accepted that therapeutic potential of ASCs may depend more on their paracrine effects than differentiation potential. The underlying mechanisms remain unclear. However, most data regarding paracrine factors were obtained from ASCs cultured in normoxic condition (20%). The present study investigated how in vivo physiological oxygen (4%) tension influenced the secretome of ASCs.
ASCs were isolated from three 8-week-old BALB/c mice. ASCs were confirmed by the expression of stem cell markers (CD44 and CD90) and their capacity to differentiate into adipocytes and osteocytes. ASCs at passage 5 were cultured in normoxic (20%) and lower oxygen (4%) incubators and conditioned for 24 h (3 cultures/group). The conditioned media (CM) from ASCs were subjected to trypsin digestion followed by analysis using automated nano-flow liquid chromatography tandem mass spectrometry. The collected LC/MS/MS data were searched against the rodent subset of the Uniprot database and the total proteomes were identified. The data were from 6 technical replicates.
A total of 28 proteins were identified and 7 proteins were unique to normoxic CM. Of the 21 common proteins detected in both normoxic and lower oxygen CM, 9 were extracellular matrix proteins. The abundance of 6 of these proteins (e.g., collagen I and laminin) differed noticeably between normoxic and lower oxygen CM. In addition, a greater amount of cytokine CXCL5 and matrix metalloproteinase (MMP)-2 was detected in lower oxygen CM than in normoxic CM while tissue inhibitor of metalloproteinase (TIMP)-1 was only detected in normoxic CM.
These results indicate that lower oxygen tension differentially regulates the secretome of ASCs. Extrapolating the results of this study to the in vivo setting, it would appear that injected ASCs may exert their anti-fibrotic and trophic effect by 1) directly regulating the balance of MMP/TIMP production and preventing collagen accumulation in ischemic hearts to decrease fibrosis, and 2) secreting trophic factors including CXCL5. These data suggest that proteomic analysis of CM is useful for elucidation of the paracrine effect of ASCs in vivo.
Abstract 76: Ablation of Parkin Attenuates Acute Cardiotoxicity of Doxorubicin Associated with Mitophagy
Authors: Huang Chengqun , Andres Allen , Ramil Jennifer , Gottlieb Roberta 
Published: July 2021

Parkin is an E3 ubiquitin ligase expressed in heart, skeletal muscle and brain. However, the function of Parkin in the heart is largely unknown. We previously showed in cardiomyocytes and the ischemic heart that Parkin translocates to mitochondria to selectively remove damaged mitochondria through autophagy. It has been shown that Doxorubicin (Dox) induces cardiotoxicity characterized by impaired mitochondrial respiration and energetic failure (PLoS One. 2010; 5:e12733). Here, we investigated the role of Parkin in acute Doxorubicin-induced cardiac dysfunction in mice.
Acute cardiotoxicity was induced by IP injection of a single dose of 15 mg/kg Doxorubicin hydrochloride in 10-12 wk-old C57BL/6J (WT) mice and Parkin knock out (PKO) mice matched by age, sex and body weight. Analysis of histology, hemodynamics, and mitochondrial content was performed 7d after Dox.
Dox induced significant loss of body weight but less in PKO mice (20% in WT vs 12% in PKO). Dox toxicity was more severe in male mice. Signs of discomfort (decreased mobility and hunched posture) were noted 4d after Dox in 90% of WT male mice vs. 20% of PKO males. Mortality at 7d was 30% in WT mice vs. 10% in PKO mice. Dox caused reduction in heart size to a greater extent (10-20%) in WT than in PKO mice. Significant deterioration of hemodynamics was seen in WT mice 7d after Dox; this was attenuated in PKO mice. Because Parkin mediates mitophagy, we examined autophagy and mitochondrial content 7d in Dox treated hearts. Dox resulted in extensive autophagy and decreased mitochondrial protein content in WT mice; this was attenuated in PKO mice.
These results suggest that high-dose Dox triggers extensive Parkin-dependent mitophagy which may contribute to acute cardiac dysfunction. We suggest that therapy directed at the PINK1-Parkin mitophagy pathway may be beneficial in the setting of doxorubicin overdose.
Abstract 9: The Virtually Mature BNP1-32 Is a Precursor for the Biologically More Active BNP1-30
Authors: Schwiebs Anja , Wang Yong , Zhu Xudong , Siems Wolf E , Walther Thomas 
Published: July 2021

The mature B-type natriuretic peptide (BNP1-32), mainly released from ventricular myocardium, has antifibrotic effects and exerts vasorelaxant and natriuretic activity leading to a reduction of blood volume and pressure. Thus, BNP is used as a drug for the treatment of decompensated heart failure.
Here we show the discovery of a new murine BNP metabolite, BNP1-30, exerting higher biological activity compared to the mature BNP1-32, in vitro and in vivo.
By mass spectrometric analysis of murine lung tissues incubated with BNP1-32 and of elution fractions of BNP1-32-perfused livers, we discovered a distinct BNP1-32 cleavage product, identified as the C-terminally truncated BNP1-30. We identified endothelin-converting enzyme (ECE) as the peptidase generating BNP1-30 from BNP1-32 by the hydrolysis of the two C-terminal leucine.
This new metabolite is significantly more efficient compared to BNP1-32 in stimulating the natriuretic peptide receptor (NPR) A. Interestingly it is also stimulating the C-type natriruretic peptide specific receptor NPRB. In parallel, dose-response curves in NPRA & -B co-transfected cell lines and stimulation of primary smooth muscle cells, endothelial cells and mesangial cells showed better efficacy for BNP1-30. In vivo, BNP1-30 reduced the mean arterial blood pressure of normotensive mice after acute infusion significantly more than BNP1-32. Additionally, BNP1-30 was also significantly more potent compared to the rodent derived pro-BNP cleavage product BNP1-45. Even more important, in a 3-day infusion experiment using spontaneously hypertensive rats (SHR), BNP1-30 was able to reduce systolic blood pressure by 30 mmHg and decreased cardiac BNP mRNA, a marker for cardiac failure, while BNP1-32 was without significant effect.
We show for the first time the occurrence of a BNP metabolite being a more efficient antihypertensive peptide than the virtually mature BNP1-32 that has been described as ‘the’ circulating biologically active form of BNP. Our results suggest that BNP1-32 is only the precursor for the more biologically active BNP1-30 leading to a fundamental revision of the natriuretic peptide system and also opens the avenue for the identification of more effective targets in the treatment of cardiovascular diseases.
Abstract 019: Diabetic Endothelial Progenitor Cells in Combination with an RGDS Presenting Peptide Amphiphile Enhance Recovery from Critical Limb Ischemia in Diabetic Mice
Authors: Vaughan Erin E , Sleep Eduard , Misener Sol , Klinger Aiko Ito , Ramirez Veronica , Abramova Tatiana V , Mackie Alexander R , Verma Suresh Kumar , Krishnamurthy Prasanna , Stupp Samuel I , Kishore Raj 
Published: July 2021

Approximately two million people suffer from critical limb ischemia (CLI) with the prevalence of the disease expected to rise. Thus, there is a crucial need to develop new therapies to enhance angiogenesis and minimize the impact of the blocked vessel(s). Cell therapy using endothelial progenitor cells (EPCs) has shown some promise, however, the cells may not remain at the site of injury long enough to significantly impact the course of the disease. Further, the use of autologous cells may be problematic as the underlying disease, such as diabetes, which resulted in CLI also appears to negatively impact the function of EPCs. Thus, we propose to use a biomaterial in combination with the EPCs to enhance both the retention of cells at the site of injury and also enhance the function of the cells. A self-assembling peptide amphiphile (PA) was developed with an attached functional group consisting of the cell-attachment sequence of peptides identified in fibronectin: RGDS.
We hypothesize that EPCs combined with RGDS PA will improve the angiogenic response in CLI. Indeed, in vitro we found that EPCs from diabetic mice (db/db) exhibited increased survival on an RGDS PA in comparison to a scrambled sequence (DGRS) PA as measured by calcein-AM and ethidium homodimer-1 staining. To test if this enhanced survival would improve critical limb ischemia in diabetic mice, uni-lateral ischemia was induced by ligation of the femoral artery. Three days post surgery ischemia was confirmed by laser Doppler and the following treatments were injected into the ischemic limb of the diabetic mice: (1) PBS (2) scrambled PA (3) RGDS (4) scrambled PA +100,000 diabetic EPCs (5) RGDS PA + 100,000 diabetic EPCs. At four weeks post-injection, blood flow (as measured by laser Doppler) was increased in the group receiving RGDS PA when compared to the other groups (n>6). Further, necrosis was decreased in the RGDS PA group and muscle regeneration, as measured by the number of central nuclei, was increased in the RGDS PA group. Taken together, these results suggest that RGDS PA in combination with db/db EPCs enhances recovery from CLI in diabetic mice.