bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 299: Simultaneous Cardiac And Adrenal Small Molecule GPCR-Gβ? Inhibition Halts The Progression Of Pressure Overload Heart Failure
Authors: Kamal Fadia A , Mickelsen Deanne , Moalem Jacob , Hammes Stephen R , Smrcka Alan V , Blaxall Burns C 
Published: July 2021

Heart failure (HF) is a progressive disease with rapidly increasing rates of morbidity and mortality. Elevated sympathetic nervous system activity, a salient feature of HF progression, leads to pathologic attenuation and desensitization of β-adrenergic receptors (β-ARs) due in part to Gβγ-mediated signaling.
In the current study, we assessed the hypothesis that the small molecule Gβγ inhibitor “gallein” is salutary in treating pre-existing HF in a clinically relevant model (pressure-overload HF model of mouse transverse aortic constriction (TAC)) by simultaneously normalizing adrenergic receptor signaling in the heart and the adrenal gland. Four weeks post-TAC, mice received daily i.p. injections of vehicle or gallein for eight weeks (n=6-8 per group). Serial echocardiography was performed through out the study. At the end of the experiment, hemodynamic studies were performed, mice were sacrificed, blood, heart, and adrenal glands were harvested for further analysis. Gallein treatment improved survival and cardiac function and reduced cardiac hypertrophy, remodeling, and fetal genes expression in TAC mice. On the molecular level, gallein recovered membrane β-AR density and attenuated GRK2-PI3Kγ membrane recruitment, and Akt-GSK-3β signaling in TAC hearts. A salutary adrenal effect of gallein was obtained in cultured mice adrenal glands and human pheochromocytoma tissue (n=3), where direct gallein treatment restored α2-AR feedback inhibitory function and concurrently reduced catecholamine production. Moreover, gallein treatment attenuated adrenal hypertrophy in TAC mice and downregulated tyrosine hydroxylase and chromogranin A protein expression in adrenal glands from TAC mice and cultured pheochromocytoma tissue as well.
In summary, our data suggest gallein as a systemic pharmacologic therapy with substantial therapeutic benefit in HF by simultaneously normalizing pathologic Gβγ-GRK2 signaling and recovering AR signaling in both the heart and the adrenal gland. In the heart, gallein mediated attenuation of cardiac remodeling probably involves inhibiting GRK2-PI3K-Akt signaling. Our data also suggest a role for small molecule Gβγ inhibition in other diseases of elevated catecholamine release, such as pheochromocytoma.
Abstract 320: Long-term Atorvastatin, But Not Pravastatin, Treatment Leads To Repressed Mitochondrial Gene Expression And Altered Cardiac Ultrastructure
Authors: Zemljic-Harpf Alice , Godoy Joseph C , Niesman Ingrid R , Schilling Jan M , Schwarz Anna , Asfaw Elizabeth K , Alvarez Erika A , Dalton Nancy D , Patel Piyush M , Head Brian P , Drummond John C , Roth David M , Kararigas Georgios , Patel Hemal H 
Published: July 2021

Statins reduce low-density lipoprotein cholesterol (LDL-C) and decrease cardiovascular events. Although statins are generally well tolerated, the FDA warns that statins may induce skeletal muscle side effects, cognitive changes and increased fasting glucose levels. Skeletal muscle biopsies from patients with statin myopathy have revealed defects in mitochondrial ultrastructure. Impaired mitochondrial function has been postulated as a key cause of statin-induced myopathy and hepatotoxicity. Long-term statin effects on cardiac muscle are currently unknown.
Wild type mice received atorvastatin, pravastatin or vehicle daily for seven months by oral gavage. Atorvastatin and pravastatin reduced LDL-C compared to vehicle. Echocardiography at two-week intervals showed no differences in %FS, %EF, circumferential fiber shortening and ventricular wall thicknesses between atorvastatin, pravastatin and vehicle treated mice. After seven months of atorvastatin, pravastatin or vehicle administration cardiac muscles (n=21-29) were analyzed, and only atorvastatin treated hearts revealed: A) swollen and misaligned mitochondria and accumulation of protein aggregates by transmission electron microscopy (n=4, each), and B) repression of mitochondrial and endoplasmatic reticulum related genes by genome-wide expression profiling. In cultured ventricular myocytes, atorvastatin, but not pravastatin; 1) down-regulated survival pathways via inhibition of ERK1/2T202/Y204, AktSer473 and mTOR signaling (p70 S6 kinaseThy421/Ser4240 and S6 RPSER 235/236), 2) reduced protein expression of caveolin-1, dystrophin, epithermal growth factor receptor and insulin receptor β, 3) decreased RhoA activation, and 4) induced apoptosis.
LDL-C reduction by atorvastatin, but not pravastatin, was associated with a repression of mitochondrial and endoplasmic reticulum related genes, an accumulation of protein aggregates, and swollen mitochondria. This is the first report demonstrating that long-term atorvastatin treatment causes adverse effects on cardiac muscle with preserved cardiac function. Whether these changes predispose atorvastatin treated hearts to contractile dysfunction after hemodynamic stress needs further investigation.
Abstract 13: Hippo Signaling Deletion During Heart Failure Reverses Functional Decline
Authors: Leach John , Heallen Todd , Zhang Min , Morikawa Yuka , Martin James 
Published: July 2021

The heart has long been thought of as a static organ incapable of repair. Recent findings have challenged this view of the heart, and have demonstrated that mature cardiomyocytes are capable of re-entering the cell-cycle. However, there is still paucity in understanding endogenous mechanisms preventing cardiomyocyte self-renewal. Our approach is to apply developmental mechanisms of cardiomyocyte cell-cycle control to the damaged heart by altering the Hippo signaling pathway.
During development Hippo signaling regulates intrinsic organ size. The core mammalian Hippo pathway includes the Ste20-like serine/threonine kinases Mst1 and Mst2, homologous to the Drosophila Hippo kinase. A subsequent kinase cascade leads to the phosphorylation of the transcription factor Yap. Phosphorylated Yap is sequestered in the cytoplasm, thus preventing transcriptional activity. We previously demonstrated Hippo signaling controls cardiomyocyte proliferation during development to restrain heart size. Additionally, using both the Apex resection (AR) and LAD-ligation (MI) models of cardiac damage, in a Hippo signaling deletion mouse, we demonstrated cardiac regeneration. Indicated by preserved cardiac function and reduced fibrotic scar formation. Additionally, these hearts display cardiomyocyte proliferation as marked by EDU incorporation, pHH3, AurkB, and Ki67 staining.
We are taking a new approach to determine the effect of Hippo signaling deletion on the failing heart, by inducing Hippo deletion after fibrotic scar formation has already occurred. To Thus far our results indicate functional recovery of the failing heart only after inducible deletion of Hippo signaling. Consistent with our previous data, preliminary results indicate adult cardiomyocytes after Hippo deletion re-enter the cell cycle. By altering Hippo signaling during heart failure and subsequently inducing cardiomyocyte proliferation we have established recovery of cardiac function. These results will greatly advance strategies to induce cardiac repair.
Abstract 132: The First Mouse Mutants of a Novel Epigenetic Modifier, Rearranged L-Myc Fusion, Display Defects in Heart Development
Authors: Bourke Lauren M , Harten Sarah , Bharti Vandhana , Oey Harry , Whitelaw Nadia , Whitelaw Emma 
Published: July 2021

Rearranged L-Myc Fusion, Rlf, was recently identified as a novel epigenetic modifier from a mouse N-ethyl-N-nitrosourea mutagenesis screen. The mice used in this study carry a multi-copy green fluorescent protein (GFP) transgene linked to an erythroid specific α-globin promoter that is sensitive to epigenetic silencing. Three independent mouse lines with mutations in Rlf were each found to have a decrease in GFP expression, suggesting Rlf acts an epigenetic modifier. Our study is the first to reveal a role for Rlf in epigenetics.
Preliminary phenotyping has found loss of Rlf results in perinatal lethality. Late gestation homozygous null Rlf mutants were found to weigh significantly less than their heterozygous or wild type littermates. Histological analysis of mid gestation embryos has identified a potential heart defect in homozygous mutants. Rlf mutants display a thin compact layer, an overabundance of trabeculae and a fenestrated interventricular septum. The Rlf mutant phenotype is reminiscent of ventricular noncompaction defects observed in humans, such as left ventricular noncompaction cardiomyopathy.
RNA-seq analysis of mid gestation Rlf wild type and null hearts, prior to the observation of a cardiac defect, was undertaken to determine which pathways may be regulated by Rlf in the heart. More genes were observed to be significantly down-regulated in Rlf mutant hearts compared to wild types. Pathway analysis of differentially expressed genes showed genes involved in cell-cell adhesion, cell signalling, glycosylation and the Notch pathway were dysregulated. These findings indicate that Rlf may play a critical role in cardiac development.
Whole genome bisulphite sequencing of different embryonic tissue/stages has shown loss of Rlf results in an increase in methylation at a large number of distinct loci across the genome. Many of which were found to overlap sites reported to be putative regulatory elements, and histone marks associated with active or poised regulatory elements in the heart.
Our data suggest Rlf plays a key role in regulating gene expression pathways during heart development. These are the first mouse mutants available to study how Rlf functions as an epigenetic modifier and the phenotypic consequences of Rlf inactivation.
Abstract 240: Strategic Distribution of the Mitochondrial Ca2+ Uniporter in Cardiac Mitochondria
Authors: de la Fuente Sergio , Vail Caitlin , Agra Elorm J , Holmstrom Kira , Sun Junhui , Mishra Jyotsna , Finkel Toren , Murphy Elizabeth , Sheu Shey-Shing , Csordas Gyorgy 
Published: July 2021

Propagation of SR-derived Ca2+ signals to the mitochondrial matrix is an important tuning tool of cardiac energy metabolism (excitation-bioenergetics coupling). Effective activation of the low-affinity mitochondrial Ca2+ uniporter (mtCU) is supported by high [Ca2+] nanodomains where SR cisternae are tethered to mitochondria. Cardiac mitochondria have large inner membrane (IMM) surface with extensive cristae folding. However, recent comparative patch clamp studies found cardiac mtCU current density extremely low.
We hypothesized that efficient excitation-bioenergetics coupling would require strategic positioning of the mtCU. We thus analyzed the distribution of mtCU’s pore protein, MCU in rat and mouse cardiomyocytes and cardiac membrane fractions. Immunofluorescence (IF) using the commercial Sigma antibody showed significant non-mitochondrial (nuclear, cyto/sarcoplasmic) crossreactions as verified in MCU-KO MEFs and cardiomyocytes. To isolate mitochondrial labeling, we performed IF of isolated mitochondria (mtIF) and immunogold electron microscopy of freshly isolated cardiomyocytes. mtIF showed ~50% of MCU-positive structures colocalized with RyR2, in line with a location preference to SR-mitochondria associations. This distribution bias was also reflected in the immunogold TEM analysis. Moreover, WB showed both MCU and calsequestrin being enriched in the same sub-mitochondrial membrane fraction separated on sucrose gradient. The prevalence of MCU and even more the essential MCU regulator (EMRE) was higher in the mitochondria “contaminating” the heavy SR (SR-associated mito membranes) than in the crude mitochondrial fraction. [Ca2+] activation of mitochondrial Ca2+ uptake at similar IMM potentials was as effective in suspensions of SR-associated mito membranes as in the crude mitochondrial fraction.
Collectively, our data suggest a location bias of the functionally mandatory mtCU channel components MCU and EMRE toward SR-mitochondrial associations. As the bias is much stronger for EMRE, the component that is required for MCU to function as a channel, it raises the possibility that EMRE availability may be a physiological limiting factor in regional mtCU activity in the cardiac muscle mitochondria.
Abstract 32: Mitral Valve Interstitial Cells With the Serotonin Transporter (SERT)-LL Polymorphism are More Efficiently Activated by Serotonin
Authors: Driesbaugh Kathryn H , Grau Juan B , Bavaria Joseph E , Alkhaleel Farrah , Lai Eric K , Shaw Richard E , Gorman Robert C , Gorman Joseph H , Levy Robert J , Ferrari Giovanni 
Published: July 2021

Prolapse of the Mitral Valve (MV) leaflet is a hallmark of several cardiac disorders such as Myxomatous MV Disease (MMVD) or ischemic MV regurgitation (MR), and is only treated surgically. Elevated levels of serotonin (5HT) have been associated with valvulopathies. Ongoing studies in our laboratory suggest that 5HT signaling plays an important role in the progression of MMVD. In addition, a 44 base polymorphism in the promoter region of the 5HT transporter (SERT) gene, designated as short (S) or long (L) allele, has been reported with Mendelian distribution, with LL resulting in increased 5HT reuptake compared to SS.
We hypothesized that patients with MMVD have enhanced 5HT signaling due to a high frequency of SERT-LL. DNA was extracted from 152 MMVD surgical patients, genomic fragment analysis performed to determine allelic frequencies, and a chi-square statistical test completed. We show that surgical patients with MMVD have a higher than expected frequency of SERT-LL (34% (52 of 152) vs. 25%). Notably, the frequency of SERT-LL is particularly enhanced (51% (21 of 41) vs. 25%) (p=0.009) in MMVD patients under 60 years old.
Based on these findings, we tested whether MV interstitial cells (MVICs) expressing SERT-LL have increased susceptibility to 5HT-mediated activation. We demonstrate that SERT-LL MVICs respond to 5HT with a 4-fold increase in smooth muscle actin (SMA) mRNA expression, a marker of VIC activation, compared to a less than 1-fold increase in SERT-LS and SERT-SS cells. The SMA response is abrogated by specific pharmacological inhibitors of the 5HT receptors 5HTR2A and 5HTR2B, and SERT, as well as siRNA knockdown. Studies of 5HTR expression in cells of each genotype are in progress.
Due to the enhanced frequency of the SERT-LL genotype among MMVD patients, particularly within the younger subset, and increased susceptibility of SERT-LL MVICs to 5HT, we postulate that the SERT-LL genotype may contribute to an increased risk of rapid disease progression by increasing the efficiency of 5HT signaling and uptake in MVICs resulting in extracellular matrix production leading to prolapse and impaired valve function. The SERT-genotype may constitute a novel means of identifying patients who may benefit from pharmacotherapy that alter 5HT-related mechanisms.
Abstract 465: G3BP1 Supports Osteogenic Mitochondrial Antiviral Signaling - NFAT Transcriptional Relays in Aortic Vascular Smooth Muscle Cells
Authors: Gay Austin T , Ramachandran Bindu , Stabley John N , Cheng Su-Li , Behrmann Abraham , Li Li , Mead Megan , Williams Bart O , Chen Zhijian , Towler Dwight A 
Published: July 2021

In vascular smooth muscle (VSM), LRP6, a Wnt co-receptor, inhibits arteriosclerotic noncanonical Wnt signals that activate protein arginine (Arg) methylation relays, converging on nuclear factor of activated T cells (NFAT). LRP6 deletion in VSM increases arteriosclerotic calcification and stiffness in low density lipoprotein receptor (LDLR)-deficient mice fed diabetogenic diets.
To study how Arg methylation mediates LRP6 actions, immunoaffinity mass spectrometry was performed on aortic VSM cell extracts from SM22-Cre;LRP6(fl/fl);LDLR-/- and LRP6(fl/fl);LDLR-/- mice. LRP6 deficiency altered Arg methylation of over 490 proteins, but only 22 exhibited increased monomethylation (MMA) with reduced dimethylation. One protein involved in atherosclerosis, G3BP1, exhibited a >30-fold increase in MMA of its C-terminal domain with LRP6 deficiency. Co-transfection confirmed that protein Arg methyltransferase 1 modified G3BP1 and was inhibited by LRP6. G3BP1 stimulated Frizzled-dependent NFAT transcription, again inhibited by LRP6. Nuclear NFATc4 and NFATc4 association with osteopontin (OPN) and alkaline phosphatase (TNAP) chromatin increased in LRP6-deficient VSM, and was reduced with G3BP1 deficiency. G3BP1 activation of NFAT required its nuclear transport domain and the MMA modified C-terminal domain to respond to Ddx58 - a modulator of mitochondrial antiviral signaling (MAVS) linked to aortic calcification. Ddx58 colocalized and synergized with G3BP1 in VSM to upregulate targets of noncanonical signaling, including OPN and TNAP. While VSM LRP6 deficiency increased Ddx58 levels, G3BP1 insufficiency reduces Ddx58 and osteogenic expression. RNAi targeting G3BP1, Ddx58 or NFATc4 reduced VSM osteogenic programs; VSM from MAVS-deficient mice exhibited reduced TNAP activity and osteogenic gene expression. Mass spectrometry data indicates that G3BP1 and Ddx58 form complexes with specific nucleoporins regulating nucleocytoplasmic transport.
Thus, G3BP1 is a target of MMA regulated by LRP6. G3BP1 promotes osteogenic signals in VSM, conveyed by a MAVS relay to regulate osteogenic transcription. Targeting G3BP1 and protein Arg methyltransferases may mitigate arteriosclerotic calcification in type 2 diabetes.
Function of the Chronically Diseased Kidney
Authors: GOTTSCHALK CARL W. 
Published: July 2021

Adaptive morphological and functional changes in the chronically diseased kidney are described in historical perspective and their correlation is stressed. The consequences of decreased glomerular filtration rate (GFR) in the presence of unchanged dietary intake on the mechanisms of excretion of substances passively reabsorbed, actively reabsorbed, and secreted are reviewed. Under these circumstances the plasma concentrations of creatinine and urea are necessarily elevated, but not that of electrolytes with regulated tubular transport. In the case of sodium, fractional excretion and GFR are reciprocally related in order to maintain unchanged rates of excretion and plasma concentration. With phosphate, regulated tubular reabsorption can prevent an increase in plasma concentration provided the GFR does not fall below approximately 25 ml/min. In the case of potassium, tubular secretion becomes apparent at marked decreases in filtration rate.
These adaptive regulatory changes are considered predictable and necessary in order for the patient to survive, and are supported by compensatory morphological changes in some of the surviving nephrons. Heterogeneity in size of the surviving nephrons, particularly the proximal tubules and glomeruli, is documented and the prediction is made that these structural changes are associated with appropriate changes in rates of transport. Data are presented demonstrating marked heterogeneity of nephron filtration rates and proximal tubular transit times in experimentally diseased kidneys. The necessity of utilizing appropriate methods of study to obtain data on individual nephrons is stressed, as is the lack of knowledge concerning the mechanisms that lead to the compensatory structural and functional changes.
It is concluded that the adaptive changes exhibited by the kidney with chronic renal disease are another and a special example of adaptive growth and, therefore, that it is more appropriate to think in terms of "adaptive nephrons" and not "intact nephrons".
Further Studies of a Natriuretic Substance Occurring in Human Urine and Plasma
Authors: SEALEY JEAN E. , LARAGH JOHN H. 
Published: July 2021

Studies are presented which provide additional physiological and biochemical characterization of a natriuretic agent which has been identified in extracts of plasma and urine of human subjects. The natriuretic activity of active fractions was consistently demonstrable in normal hydropenic rats as well as in rats with congenital diabetes insipidus. The induced natriuresis usually developed slowly and could last for several hours. The natriuresis was not usually associated with increases in water or potassium excretion. It occurred without measurable changes in glomerular filtration rate or arterial blood pressure. Altogether, these results suggest that the substance acts to depress sodium reabsorption in the distal tubule.
In bioassays of similarly prepared fractions utilizing direct perfusion of the renal artery, an immediate and transient natriuresis has been consistently observed. This immediate response appears to be produced by a substance different from that responsible for the delayed and more prolonged natriuresis, because the immediate response was always associated with a rise in blood pressure in the assay animal. Also, the activity of the agent responsible for the immediate natriuresis did not fluctuate with changes in sodium balance in the experimental subjects. Contamination with this substance may explain the occasional immediate response observed in earlier assays. This experience points to the importance of monitoring blood pressure during assays for natriuretic agents.
Additional fractionation studies continue to suggest that the substance occurring in salt-loaded human subjects which causes the more delayed and prolonged natriuresis in assay animals appears to be of a molecular weight of from 10,000 to 50,000.
Abstract WP12: Downstream Clot Fragment Migration During Endovascular Clot Extraction Adversely Affects Clinical Outcome
Authors: Frey James L , Darbonne Carol , Chapple Kristina M , Saldivar Christina , Saha Kamala , Clark Joni , Taylor Heather 
Published: July 2021

Background and Purpose:
FDA approval of endovascular clot extraction devices that are used in stroke is based on efficacy for opening target arteries safely. Favorable clinical outcomes using devices currently available, however, is limited. Time to treat and stroke severity are obvious contributors, but a factor that receives little attention is intraoperative downstream migration of clot fragments. We assessed the effect of migrated clot fragments on clinical outcome in patients treated at our institution.

Methods:
With IRB approval, we retrospectively reviewed charts, procedure reports, and images of all patients with M1 occlusions treated with endovascular clot extraction within the past 5 years to compare relevant variables and discharge outcomes in patients whose arteries were ultimately “open” (OP) versus “open with fragments” (OF).

Results:
Thirty four patients were treated (21 Penumbra, 7 Merci retriever, 6 Solitaire), all under general anesthesia. Numbers of patients in each category of final vessel patency were: OP=15, OF=19.

No significant intergroup differences were found (means) for age (60), gender (male 55%), time from onset to treatment (4.71 hours), admission BP (141/82), duration of anesthesia (2.1 hrs), mean blood pressure during anesthesia (132/70), admission NIHSS (13.8), pretreatment with IV-rtPA (70%).
OP patients were more likely to have had an atheroembolic than cardiac source of stroke (p<0.03), as well as treatment with Solitaire stent (all 6 Solitaire patients were OP).
OF were more likely to have had IV-rtPA (p<0.15), treatment with Penumbra (p<0.03), and adjunctive use of IA-rtPA and abciximab for target clot (p<0.09).
OP had lower discharge NIHSS (6.79 v 13.22; p<.03); greater change in NIHSS
(-6.21 v -1.89; p<0.03); discharge mRS=0-2 (47% v 21%; p<0.15); discharge mRS=0-3 (53% v 79%; p<0.005); discharged home (33% v 11%; p<0.2).
There was one death in each group (NS), one sICH in OF, and length of stay was 8 days in both.

Conclusion:
Although our numbers are small, they strongly suggest an adverse effect of downstream clot fragments on outcomes. Awareness of this phenomenon should be useful in the approval process for future devices, as well as in the evaluation of post-marketing device use.