bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 529: Asporin - Extracellular Matrix Protein Mitigates Pathological Remodeling
Authors: Piplani Honit , Sharma Ankush , Huang Chengqun , Sin Jon , de Freitas Germano Juliana , Mentzer Robert M , Andres Allen M , Gottlieb Roberta A
Published: February 2019

The cardiac extracellular matrix is a complex network of proteins and plays a key role in cardiac remodeling after myocardial infarction. One of the extracellular matrix proteins, asporin, is a member of the SLRP family and inhibits TGFβ signaling. However, very little is known about the function and regulation of asporin in cardiac remodeling. Using bioinformatics approach, microarray data analysis from publicly available datasets identified asporin as a top candidate showing an increase in left ventricle tissue with ischemic cardiomyopathy as compared to control donor hearts. To confirm, we detected an increase in asporin expression in paired heart biopsies taken before and after cardiopulmonary bypass surgery by western blot analysis. Our group showed that glucagon like receptor 1 agonist (GLP-1Ra) is beneficial for cardiac remodeling and prevents fibrosis. In a permanent coronary artery ligation model, we found increased extracellular asporin expression after 30 days in border zone and scar area with GLP-1Ra treatment compared to vehicle-treatment. To further elucidate the mechanism of asporin secretion, we used H9c2 cells as well as left ventricle tissue from mice and found that asporin was predominantly present in the heavy membrane enriched fraction (8,000xg pellet from postnuclear supernatant). Sequence analysis of asporin protein using SecretomeP 2.0 server predicted asporin might use the non-conventional form of secretion (secretory autophagy). Differentiation of H9c2 cells is accompanied by autophagy and mitochondrial biogenesis, and we found that the abundance of asporin in total lysate and heavy membrane fraction decreased suggesting it could be released via secretory autophagy. Using recombinant human asporin, we demonstrated that asporin stimulates an increase in LC3 and p62 in parallel to a decrease in COX IV and SMAD2 phosphorylation, indicating mitophagy induction and a decrease in TGFβ signaling. Based on our preliminary data and sequence comparison to a previously reported human peptide, we developed a rodent asporin peptide which is predicted to induce mitophagy while decreasing TGFβ signaling to prevent fibrosis. Studies are ongoing to establish the clinical relevance of asporin in animal models of ischemic injury.
Abstract 530: The Ufm1 Specific Ligase 1 Regulates Endoplasmic Reticulum Homeostasis and Protects Against Heart Failure
Authors: Li Jie , Yue Guihua , Ma Wenxia , Zhang Aizhen , Zou Jianqiu , Wang Jun , Li Honglin , Su Huabo
Published: February 2019

Protein modifications by ubiquitin and ubiquitin-like proteins are emerging as an important regulatory mechanism of protein function and involved in various cellular processes. Ufm1 (ubiquitin-fold modifier 1) is a novel ubiquitin-like protein that modifies protein targets in a UBA5 (E1) - Ufc1 (E2) - Ufl1 (E3) dependent manner. While defects in ubiquitin- and SUMO-modification have been shown to provoke cardiac remodeling and dysfunction, the importance of Ufm1 modification has not been explored in the normal and stressed heart. Western blotting revealed that Ufm1 specific ligase 1 (Ufl1), an enzyme essential for Ufm1 modification, was increased in hypertrophic mouse hearts but reduced in the failing hearts of patients with dilated cardiomyopathy. To determine the functional role of Ufl1 in the heart, we generated a cardiac-specific knockout mouse and showed that Ufl1-deficient mice developed age-dependent cardiomyopathy and heart failure, as indicated by elevated cardiac fetal gene expression, increased fibrosis and impaired cardiac contractility. When challenged with pressure overload, Ufl1-deficient hearts exhibited remarkably greater hypertrophy, exacerbated fibrosis and worsened cardiac contractility compared with control counterparts. Transcriptome analysis identified that genes associated with the endoplasmic reticulum (ER) function were dysregulated in Ufl1-deficient hearts. Biochemical analysis revealed that excessive ER stress preceded and deteriorated along with the development of cardiomyopathy in Ufl1-deficient hearts. Mechanistically, Ufl1 depletion impaired PERK signaling and aggravated cardiomyocyte cell death following ER stress. Administration of the chemical ER chaperone tauroursodeoxycholic acid to Ufl1-deficient mice alleviated ER stress and attenuated pressure overload-induced cardiac dysfunction. Our results advance a novel concept that the Ufm1 system is essential for cardiac homeostasis through regulation of ER function and that upregulation of myocardial Ufl1 could be protective against heart failure.
Abstract 531: A Lack in Endogenous Proteasome Regulation Provokes Exacerbated Cardiac Remodeling and Premature Heart Failure Following Catecholamine Challenge
Authors: Trogisch Felix A , Koser Franziska , Jungmann Andreas , Müller Oliver J , Hecker Markus , Drews Oliver
Published: February 2019

Introduction:
Cardiac remodeling is associated with a dynamic regulation of the ubiquitin-proteasome system. Our previous studies revealed cardiac induction of the non-essential proteasome subunit low molecular mass peptide 2 (Lmp2) as an early feature of beta-adrenoreceptor overstimulation, as present in chronic human heart disease. However, the impact of Lmp2 upregulation on the progress of cardiac remodeling has not been characterized in detail so far.

Objective:
Aim of the study was to monitor the contribution of Lmp2 to cardiac remodeling in a mouse model of beta-adrenoceptor overstimulation.

Methods & Results:
Unchallenged adult mice congenitally lacking Lmp2 (KO) showed no cardiac abnormality including systolic and diastolic function or morphology. After 7 days of continuous isoproterenol administration (30 mg/kg/d using subcutaneous osmotic mini-pumps), both fractional shortening and active diastolic filling of the left ventricle were significantly reduced (by 32%) in Lmp2 KO mice as compared to wildtype littermates (p<0.01, n≥9). Cardiomyocyte-specific adeno-associated virus serotype 9-mediated transfer of the gene encoding Lmp2 rescued cardiac function in Lmp2 KO mice, suggesting that Lmp2 deficiency in cardiomyocytes causes this cardiac phenotype. The decline of systolic and diastolic function was accompanied by increased gain in heart weight to body weight ratio as well as wall thickness, ruling out dilatation of the left ventricle. On cellular level, cardiomyocyte cross-sectional area was markedly augmented (+52% vs. +32% Lmp2 KO vs. WT) as compared to corresponding sham-treated mice (p<0.05, n=3) without altering cardiomyocyte length. To exclude an impact of the remodeling process
per se
on measuring ventricular function, cardiac contractility was directly assessed by using speckle-tracking analyses. Interestingly, peak circumferential strain and strain rate were both markedly decreased in Lmp2 KO mice following isoproterenol treatment as compared to WT mice.

Conclusions:
Cardiac, presumably cardiomyocyte induction of Lmp2 seems to be protective in the course of cardiac hypertrophy while lack of Lmp2 exacerbates cardiac remodeling, causing a decline of cardiac function despite increased ventricular muscle mass.
Abstract 534: Modulatory Effect of Nkx2.5+ Cardiomyoblast Secreted Exosomes in Cardiometabolism
Authors: Chen Wen-Pin , Lian Wei-Ping , You Min-Yi , Li You-Yi
Published: February 2019

It was found cardiac precursors secreted exosomes (CPC-exo) may have anti-apoptotic and anti-fibrotic actions to facilitate cardiac repair in the damaged hearts. It remains unclear the effect of CPC-exo in cardiometabolism. The aim of the study was to assess the modulatory action of CPC-exo in cardiometabolism of cardiomyopathic cardiomyocytes. Nkx2.5+ cardiomyoblasts were enzymatically isolated and were purified by FACS sorter from mouse embryonic stem cells under cardiomyogenic differentiation or transgenic mice hearts (2 weeks old) carrying GFP reporter driven by Nkx2.5-enhancer for the purification of the exosomes (mESC-Nkx2.5+exo and postnatal-Nkx2.5+exo) from the culture medium by ExoQuick-TC. The vesicle size was further measured by Nanosight. The exosomal miRNA profile was characterized by miRNA microarray. It was further compared the different effect of mESC-Nkx2.5+exo and postnatal-Nkx2.5+exo in the mitochondrial function of human cardiomyocytes derived from iPSC of left ventricle non compaction (LVNC) patients (LVNC-hiPSC-CM) by Agilent seahorse XF24 analyzer. Cell shortening was measured by Ionoptix system. It was found the defect of cardiac mitochondrial function associated with the weak cell shortening in LVNC-hiPSC-CM on day 70 after differentiation. With the treatment of mESC-Nkx2.5+exo and postnatal-Nkx2.5+exo during day 50-70, the mitochondrial function and cell shortening of LVNC-hiPSC-CM were significantly improved on day 70. The functional exosomal miRNAs were characterized in advance in this study. In conclusion, CPC-exo may exert the benefit in the improvement of cardiometabolism in cardiomyopathic cardiomyocytes.
Abstract 544: Gja1-20k Uses the Actin Cytoskeleton to Promote Both Mitochondrial Fission and Fusion
Authors: Shimura Daisuke , Baum Rachel , Xiao Shaohua , Hong TingTing , Shaw Robin M
Published: February 2019

Connexin (Cx) 43 is encoded by the GJA1 gene and GJA1-20k has been identified as an N-terminal truncation of Cx43 generated endogenously by internal translation initiation in heart and other organs. We’ve previously identified that GJA1-20k, which increases with ischemic injury, can organize actin networks and also is strongly co-localized with mitochondria, utilizing the cytoskeleton to preserve mitochondrial distribution during stress. Mitochondrial distribution and morphology are associated with metabolic function, and thus we are interested in how GJA1-20k affects mitochondrial shape and connectivity. We transfected GFP-tagged GJA1-20k plasmids into HEK293T cells and assessed mitochondrial distribution and morphology by fluorescence microscopy. Mitochondria exposed to GJA1-20k are smaller, more circular, and more distributed than mitochondria exposed to a control plasmid. Quantitative image analysis indicates an increase in mitochondrial count but no increase in mitochondrial area, indicating greater mitochondrial fission in the presence of GJA1-20k. Paradoxically, acute disruption of actin with Latrunculin A decreased mitochondrial count, yet increased mitochondrial area, indicating acute fusion. Mitochondrial fusion was also observed by live cell imaging, and with high doses of GJA1-20k. Latrunculin A did not affect mitochondrial morphology in cells without GJA-20k. Together these data suggest that GJA1-20k, a mitochondrial and actin associated scaffold, has multiple effects on mitochondrial morphology. At baseline GJA1-20k promotes mitochondrial-actin association, promoting fission and cellular distribution. Yet, GJA1-20k also promotes mitochondrial membrane-membrane association that, in the presence of actin disruption, resulting in mitochondrial fusion. These data suggest GJA1-20k not only organizes mitochondria under physiologic conditions, but during ischemia, it promotes mitochondrial fusion, enhancing tissue survival during stress.
Abstract 553: Inhibition of Microrna-21 Prevents Myocardial Remodelling and Dysfunction in a Pig Model of Ischemia/reperfusion Injury
Authors: Ramanujam Deepak Prabhu , Hinkel Rabea , Kazcmarek Veronika , Howe Andrea , Klett Katharina , Dueck Anne , Thum Thomas , Laugwitz Karl-Ludwig , Kupatt Christian , Engelhardt Stefan
Published: February 2019

Background:
Upregulation of microRNA-21 (miR-21) has been associated with myocardial disease and its systemic inhibition was effective in reducing cardiac fibrosis and dysfunction in rodent models. However, the translation to human disease is challenging, as systemic application of miR inhibitors does not achieve adequate delivery in most organs including the heart. Here, we sought to test the applicability and therapeutic efficacy of local, catheter-based delivery of antimiR-21 in a large animal model of heart failure.

Methods and results:
Pigs underwent percutaneous occlusion of the left coronary artery for 60 minutes and were followed up for 33 days. A synthetic inhibitor against miR-21 (LNA-antimiR-21, 10 mg per application) was applied locally by intracoronary infusion at days 5 and 19 after the injury. AntimiR-21 effectively suppressed the I/R-induced increase of miR-21. At 33 days after I/R, LNA-21-treated hearts exhibited reduced cardiac fibrosis and hypertrophy, and improved cardiac function (ejection fraction: I/R control 22±1% vs. I/R LNA-21 33±2%). RNA sequencing of ischemic myocardium revealed a significant enrichment for miR-21 targets in anti-miR-21 treated hearts. Mechanistically, antimiR-21 interfered with a number of signalling pathways involved in myocardial remodelling including the MAPK-ERK signalling cascade.

Conclusion:
Taken together, our study provides the first evidence for the feasibility and therapeutic efficacy of miR-21 inhibition in a large animal model of myocardial ischemia. AntimiR-21 prevented the structural and functional consequences of ischemic myocardial damage.
Abstract 555: Exosomal MicroRNAs Contribute to Chronic Heart Failure Through Dysregulating Nuclear Factor Erythroid 2-Related Factor 2/Antioxidant Response Element Signaling
Authors: Tian Changhai , Gao Lie , Zucker Irving H
Published: February 2019

The imbalance between the synthesis of free radicals and their elimination by antioxidant defense systems, results in macromolecular damage and disruption of cellular redox signaling, affecting cardiac structure and function, and thus contributing to the contractile dysfunction, myocardial hypertrophy and fibrosis. The Nrf2/Keap1/ARE signaling pathway is an important antioxidant defense mechanism and is closely associated with oxidative stress-mediated cardiac remodeling in CHF. Keap1, a redox-regulated substrate adaptor protein for the Cul3-dependent ubiquitin ligase complex generally mediates Nrf2 degradation.
In this study,
we hypothesized that circulating exosomal microRNAs may be involved in the translational repression of Nrf2 mRNA in the setting of CHF.
We analyzed microRNA levels in exosomes from plasma of Sham and CHF rats. We found that three microRNAs including microRNA-27a, -28-3p and -34a which have potential binding sites in the 3’-UTR of Nrf2 mRNA, were highly enriched in exosomes derived from the circulation of CHF rats compared with sham rats (Fig.1). We labeled exosomes from CHF rats derived from plasma with PKH26 and administrated fluorescence-labeled exosomes into mice by various routes in order to track their distribution
in vivo
using the IVIS imaging system. Our preliminary data show that exosome distribution is dependent on the route of administration, and that circulating exosomes target the brain and heart. Taken together, these findings suggest that increased circulating exosomal microRNAs may contribute to Nrf2 dysregulation in CHF. These microRNAs may also serve as biomarkers for early diagnosis of CHF and therapeutic targets for CHF.
Abstract 556: Intramyocardial EphrinA1-Fc Preserves Mitochondrial Structure and Bioenergetics Post-Myocardial Infarction
Authors: Horton Julie , Torres Maria , McLaughlin Kelsey , Renegar Randall , Sharma Uma , Valsaraj Smrithi , Sharaf Omar , Whitehurst K’Shylah , Sarathy Brinda , Neufer Darrell , Virag Jitka A
Published: February 2019

EphrinA1, a receptor tyrosine kinase ligand expressed in the plasma membrane of healthy cardiomyocytes, is reduced following acute myocardial ischemia (I)/reperfusion (R) injury in mice. Intramyocardial injection of recombinant EphrinA1-Fc at the time of LAD ligation attenuated infarct injury by 46% and completely preserved cardiac function in I/R (30min I/24hrs R). This was accompanied by reduced inflammation, attenuation of apoptosis, enhanced autophagy, and modulation of metabolic pathways that promote more efficient energy utilization. To examine the mechanism by which this occurs, mitochondrial structure and function was examined in 10 wk-old B6129SF2/J male mice given intramyocardial EphrinA1-Fc or IgG-Fc at LAD occlusion and subsequently reperfused for 24hrs. Permeabilized cardiac muscle fibers were isolated from a portion of the infarct margin of the left ventricle to assess mitochondrial function and energetics. EphrinA1-Fc prevented the 30% loss (p<0.005) in mitochondrial respiratory capacity in the absence of changes in H
2
O
2
emitting potential. Moreover, using a titrated creatine kinase energetic clamp, we found that EphrinA1-Fc improved the mitochondrial thermodynamic force-flow relationship by increasing OXPHOS conductance (+55% vmax, p<0.005), without changes in ADP affinity. Another small portion of the infarct margin was fixed and processed for transmission electron microscopy imaging which revealed that EphrinA1-Fc treatment prevented the MI-induced loss of sarcomere alignment and mitochondrial organization along the Z disks, as well as disorganization of the cristae. There was also significantly less lipid droplet accumulation and preservation of intermitochondrial junctions. Morphometric analyses of mitochondria are in progress as are Western blot assays to identify the proteins involved. Myocardial strain analyses are also underway to explore and pinpoint regional changes in contractile function. Collectively, these data demonstrate that intramyocardial injection of EphrinA1-Fc attenuates I/R injury by preserving the mitochondrial network structure and bioenergetic capacity. The robust cardioprotection afforded by ephrinA1-Fc offers promise as a novel therapeutic for the treatment of acute MI.
Abstract 557: Exosome Biogenesis/Uptake Mediates Cardioprotection by Globular Adiponectin but Not High Molecular Weight Adiponectin
Authors: Wang Yajing , Gan Lu , Xie Dina , Zhao Dajun , Gao Erhe , Koch Walter J. , Ma Xinliang
Published: February 2019

Objectives:
Adiponectin, a multifunction adipokine with established cardioprotective effect, presents in high molecular weight (HMW) and globular isotype (gAPN). Recent study demonstrated that HMW cardioprotection depends on T-Cadherin (TCad). However, whether TCad also mediates the cardioprotective effects of gAPN, an isotype with much greater biological activity and wildly utilized in metabolic/cardiovascular investigations, remains unclear.

Methods and results:
Adult male WT, AdipoR1KO and TCadKO mice were subjected to MI, treated with vehicle or gAPN, and followed for 4 weeks. Knockout of AdipoR1, but not Tcad, abolished the cardioprotective effects of gAPN observed in WT mice, indicating that AdipoR1 but not Tcad mediates gAPN cardioprotection. Unexpectedly, we observed that gAPN cardioprotection was significantly attenuated when animals were pre-treated with GW4869, suggesting exosome involvement. To further delineate whether gAPN regulates exosome biogenesis and/or uptake and which stage is mediated by AdipoR1, cardiomyocytes were isolated from adult AdipoR1KO and TCadKO mice. Effects of gAPN and HMW upon exosome generation and uptake were evaluated. Surprisingly, cardiomyocyte exosome production was dramatically increased (8-fold) when cells were treated with gAPN but not with HMW (at 5-fold concentration of gAPN). Moreover, gAPN increases cardiomyocyte exosome production in a receptor-independent fashion and is achieved by regulating ESCRT-multivesicular body (MVB) pathway. However, gAPN stimulated exosome uptake and cellular protection observed in WT cardiomyocytes was abolished in AdipoR1KO-derived but no TCadKO-derived cardiomyocytes.

Conclusions:
These data demonstrated that gAPN and HMW cardioprotection exhibits different receptor dependence and is mediated by distinct mechanisms. HMW protects heart via binding with TCad. However, gAPN has a unique ability, promoting exosome biogenesis in a receptor-independent fashion and stimulating exosome uptake and cardioprotection in an AdipoR1-dependent manner. These results indicate that gAPN is superior to HMW in concerning cardioprotection against ischemia heart injury, and is a promising therapeutic strategy in patients with coronary artery disease.
Abstract 558: Melatonin Exerts Cardioprotective Effects Under Chronic Neuropathic Pain Through Rip1-rip3-mlkl and Rip3-camkii Pathway Mediating Myocardial Necroptosis in Ischemia Reperfusion Injury
Authors: Yang Zheng , Li Chen , Xue Han , Wang Yishi , Ma Heng
Published: February 2019

Objectives:
Chronic pain is not an isolated pathophysiological symptom, myocardial ischemic/reperfusion injury contributes significantly to morbidity and mortality among people reporting chronic pain. However, the related mechanisms remain elusive. TNF-α triggered necroptosis contributes a lot to MI/R in jury and RIP3 plays an important role during this process under chronic pain condition. Melatonin has analgesia and cardioprotective effects, which may regulate necroptosis in chronic pain related MI/R injury. The aim of this study was to investigate the roles of melatonin in MI/R injury under chronic pain condition and the underlying mechanism.

Methods:
In this study, chronic neuropathic pain was induced by spared nerve injury (SNI) model. RIP3 KO and wild-type (WT) littermates were subjected to MI/R in vivo. Melatonin was administrated to mice 10 minutes before reperfusion.

Results:
SNI-WT mice manifested enhanced nociception and TNF-α induced necroptosis. SNI increased RIP1-RIP3 necrosome formation provoked RIP1-RIP3-MLKL and RIP3-CaMKII signaling, which led to exacerbated MI/R injury and higher mortality compared with control-WT mice. Chronic pain induced susceptibility to MI/R injury was decreased by RIP3 deficiency associated with impaired RIP1-RIP3-MLKL and RIP3-CaMKII signaling. Melatonin treatment in SNI-WT mice showed inhibited necroptosis and decreased TNF-α elevation and ROS production. RIP3 was also inhibited by melatonin treatment followed with impaired MLKL and CaMKII activation, which subsequently decreased MI/R injury (impaired serum LDH level, minimized infarct size and elevated cardiac function).

Conclusions:
These results suggested that chronic pain rendered cardiomyocytes more susceptible to MI/R injury. RIP3 plays an important role in mediating necroptosis in response to MI/R injury under chronic pain condition. Melatonin treatment could inhibited TNF-α triggered necroptosis and downregulated RIP3 mediating MLKL and CaMKII signaling which alleviated ROS production and cardiomyocytes death.
Abstract 565: Coxsackievirus Infection During the First Trimester of Pregnancy Suppresses Cardiomyocyte Proliferation Leading to Congenital Heart Defects
Authors: Sharma Vipul , Goessling Lisa , Rohrbough Sara , Brar Anoop , Eghtesady Pirooz
Published: February 2019

Purpose:
Coxsackievirus B (CVB), known to be the most common cause of myocarditis, target cardiomyocytes through Coxsackie and Adenovirus Receptor, which is highly expressed in the fetal heart. We hypothesized that CVB infection during early pregnancy may play a role in the pathogenesis of congenital heart disease (CHD).

Methods:
Pregnant C57Bl/6J mice were infected with varying doses of CVB3 (Nancy strain), 1x10
6
, 2.5x10
6
, and 5x10
6
TCID50, between embryonic days (E) 5-11. Presence of the virus was confirmed by RT-PCR and infectivity assay. Fetal heart phenotype was assessed by histology. RNA collected from fetal hearts using laser microdissection was analyzed by RNA-Seq to understand changes at the molecular level after infection. Results were confirmed by immunohistochemistry and qPCR. To determine if virus serotype alters the outcome, CVB1, CVB4, and a combination of CVB3 and CVB4 were used for infection. To assess the clinical significance serum from pregnant human subjects, grouped based on outcome of pregnancy (healthy baby vs babies with CHD), was checked for the presence of CVB serotypes.

Results:
Fetuses developed spectrum of CHD (38.2%, n=78/204): ventricular septal defect, double outlet right ventricle, and non-compaction of ventricular myocardium after CVB3 infection. Approximately one third of the fetuses were resorbed (38.7%, n=129/333). Infection at E9 led to the highest incidence of VSD with female fetuses being more susceptible to the phenotype. Transcripts found to be differentially expressed in hearts with VSDs were mediators of the Transforming growth factor β and Extracellular matrix signaling pathways. Consistent with the former, expression levels of BMP2 and Smad1/5/9 mRNA were elevated in fetal hearts with VSDs. This correlated with suppressed proliferation of cardiomyocytes in these mice. In pregnant human subjects who had babies with CHD elevated titers of antibodies against CVB3, CVB4, and CVB3+CVB4 were seen. In mice, infection with CVB1, CVB4, or CVB3+4 showed that CVB3 in combination with CVB4 induces more VSDs than infection with any one serotype.

Conclusion:
There is a critical window during pregnancy where CVB infection leads to abnormal cardiac development likely through reduction of cardiomyocyte proliferation.
Abstract 572: Role Of Human Cardiac RLC In Modulating The Super-relaxed State Of Myosin: A Cardiomyopathy Perspective
Authors: Sa Na , Tomasic Ivan , Gollapudi Sampath , Evangelista Ferdinand , Green Kristina , Nag Suman
Published: February 2019

Myosin regulatory light chain (RLC) is a major regulatory subunit of the myosin molecule, the role of which has been well-characterized in non-striated muscle. However, in striated muscle, its purpose is less well defined, and it is only in the past decade that researchers have started unraveling the function of RLC and its phosphorylation in muscle contraction. Mutations in this protein result in ~ 2% of total familial cardiomyopathy, an autosomal dominant disorder, manifested by ventricular and septal hypertrophy and myofibrillar disarray that can lead to sudden cardiac death. In this study, we report the role of human cardiac RLC in forming the super-relaxed state (SRX) of myosin in reconstituted full-length cardiac myosin thick filaments. We show that the presence of RLC fine-tunes the ability of myosin to form the SRX state and that its removal depopulates the SRX state. A similar reduction in SRX population is also achieved by phosphorylating the RLC with MLCK. The second mechanism of RLC-mediated regulation in muscle is thought to be by the binding of either Mg
2+
or Ca
2+
to the N-terminal EF-hand domain. Mg
2+
did not affect myosin SRX population, but increasing Ca
2+
enhanced the population of the myosin SRX state. Preliminary SRX studies on cardiomyopathy-causing RLC mutants R58Q (HCM), K104E (HCM) and D94A (DCM) show that none of the mutants affects the SRX population in the dephosphorylated state of the RLC; however these mutants also do not affect the SRX population when RLC is phosphorylated, unlike the wild-type. Additionally, in micro-scale thermophoresis binding experiments, only the dephosphorylated form of the DCM-causing D94A RLC mutant exhibits weaker binding to the myosin lever arm as compared to WT RLC. Binding of the mutants resembles WT upon phosphorylation. Altogether, these observations demonstrate that either RLC phosphorylation or Ca
2+
binding to RLC can alter the number of accessible myosin heads for contraction and cardiomyopathy-causing RLC mutants can modify this mechanism to varying extents.
Abstract 574: An Amino-Terminal Peptide of GRK5 Prevents Pathological Cardiac Hypertrophy in Response to Pharmacological and Surgical Stress
Authors: Coleman Ryan
Published: February 2019

Introduction:
The pathogenesis and progression of heart failure (HF) encompasses maladaptive cardiac hypertrophy, ventricular remodeling, and contractile dysfunction. A gene expression maladaptation in HF is an increase in expression of G protein-coupled receptor kinase (GRK5). Recently, non-canonical roles for GRK5 have been uncovered that are crucial for the development of maladaptive hypertrophy and these are due to its nuclear translocation. We have shown that nuclear targeting of GRK5 is mediated by an amino-terminal (NT) domain that can bind calmodulin.

Hypothesis:
We hypothesize that expression of a peptide encoding the NT of GRK5 that includes this calmodulin binding domain will act as a calmodulin inhibitor preventing the nuclear accumulation of GRK5 and inhibit its non-canonical pathological activities.

Methods:
To further study this, neonatal rat ventricular cardiomyocytes overexpressing GRK5-NT or a negative control virus were treated with 50μM phenylephrine (PE) or vehicle for 48 hours to induce a hypertrophic response. Cell areas and transcript levels of fetal genes were measured after treatment. Novel transgenic GRK5-NT and non-transgenic littermate control (NLC) mice were characterized before and 4 weeks after transverse aortic constriction (TAC) or sham surgery. Echocardiography, myocyte cross-sectional area, and heart weight to tibia length metrics were used to evaluate TAC response.

Results:
In vitro, expression of the GRK5-NT peptide abrogated the hypertrophic effects of PE, both in terms of fetal gene re-activation and myocyte size. In vivo, transgenic GRK5-NT mice did not demonstrate any hypertrophy after 4 weeks of TAC and cardiac dysfunction seen in NLC mice at this time point was absent in GRK5-NT mice. Further, GRK5-NT TAC mice showed no increase in cell surface area compared to their respective sham controls post-TAC.

Conclusion:
In this study, we show that the GRK5-NT peptide prevents the pathological response to pharmacological and surgical models of cardiac hypertrophy. Further studies in vivo will reveal whether GRK5-NT can preserve function in the long-term, and further in vitro characterization will reveal whether the mechanism is GRK5-dependent.
Abstract 575: Primary Cilia of Cardiac Neural Crest Cells Orchestrate Multiple Aspects of Cardiovascular Development
Authors: Fitzsimons Lindsey A , Moran Adrian M , Tucker Kerry L
Published: February 2019

Cardiac neural crest cells (CNCC) are a specialized population of migratory neural crest cells that contribute to the developing cardiac outflow tract (OFT) and endocardial cushions (ECC). Like many eukaryotic cells, CNCC also possess primary cilia, which function as membrane-bound sensory organelles involved in intra- and extra-cellular communications in developing tissues. Previous work in our laboratory has shown that primary cilia of cardiac progenitor populations are critical orchestrators of both the septation and alignment of the developing OFT and interventricular septum. Our current
in vivo
models have refined the elimination of primary cilia to CNCC of the embryonic mouse heart using multiple neural crest-specific Cre drivers (
Wnt1
:Cre-Danielian et al,1998;
Wnt1
:Cre2-Soriano et al, 2013) crossed with the
Ift88
flox/flox
mouse (Haycraft et al, 2007), resulting in elimination of primary cilia from CNCC during early embryonic heart development. Additionally, we have utilized a Td-Tomato (Tdt) reporter mouse line to track the migration of CNCC during various embryonic timepoints. Use of this reporter line revealed transient Tdt-positive CNCC contributions to the ventricular portion of the developing myocardium, in addition to the expected CNCC contributions to in the OFT and ECC regions. The resultant mutant phenotypes included a high incidence of outflow tract defects, impaired septation of the membranous interventricular septum, non-compaction of the developing ventricular myocardium, and perinatal lethality. Our data combine various immunohistochemical approaches to document, characterize, and quantify the novel presence of CNCC in the developing embryonic ventricular myocardium. These data suggest a potential modulatory role for primary cilia of CNCC in the development and maturation of the ventricular myocardium. Primary cilia-mediated signal transduction events that could account for the descried phenotypes are currently being elucidated.
Abstract 579: Beta-blockers Regulate Hypoxia Sensing of Beta Adrenergic Receptors
Authors: Sun Yu , Gupta Manveen K , Prasad Sathyamangla V
Published: February 2019

Beta adrenergic receptors (βARs) are one of the most powerful regulators of cardiac function. Activation of βAR leads to phosphorylation by G-protein coupled receptor kinase 2 and β-arrestin binding resulting in desensitization. The phosphorylated βARs are resensitized by dephosphorylation by PP2A. Besides classical agonist activation, increasing evidence shows that βARs can be regulated by inflammation and oxidative stress. In this regard, we have shown that βARs can be regulated by hypoxia wherein hypoxia increases the β2AR phosphorylation and HIFα accumulation (Cheong et. al., 2016). However, the mechanisms of βARs regulation in hypoxia are not well understood and we postulated that shift in homeostasis existing between kinase and phosphatase driven mechanisms may underlie βAR dysfunction. To test this hypothesis, β2AR HEK 293 cells were exposed to hypoxia (2% O
2
) and assessed the mechanisms underlying desensitization (kinases) and resensitization (PP2A). Our studies showed that 6 hours of hypoxia treatment resulted in increase of βAR phosphorylation and GRK2 expression. Assessment of βAR phosphorylation in the plasma membrane and endosomal fractions surprisingly, shoed marked increase in β2AR phosphorylation in the endosomal fraction. Furthermore, we also observed that receptor associated PP2A activity was reduced specifically in the endosomes with minimal changes of activity at the plasma membranes. Given that β-blockers confer beneficial effects, we tested whether β-blockers (propranolol or carvedilol) would prevent βARs phosphorylation under hypoxia or normoxia. Consistently, β-blocker treatment in normoxia results in increased β2AR phosphorylation. Remarkably β-blocker treatment in hypoxia results in loss of β2AR phosphorylation and reduction in GRK2 expression. These studies suggest agonist-independent hypoxia-driven β2AR dysfunction can be ameliorated by β-blockers and the underlying mechanisms driving this hypoxia mediated β2AR dysfunction will be discussed in the presentation. These unexpected findings have significant clinical implications given that hypoxia underlies stroke/myocardial infarction and understanding these mechanisms could provide novel insights into the benefits provided by β-blockers.
Abstract 584: FTO-Dependent m6A Regulates Cardiomyocyte and Cardiac Function During Remodeling and Repair
Authors: Mathiyalagan Prabhu , Adamiak Marta , Mayourian Joshua , Liang Yaxuan , Sassi Yassine , Agarwal Neha , Jha Divya , Ishikawa Kiyotake , Zhang Shihong , Kohlbrenner Erik , Yin Xiaoke , Chepurko Elena , Chen Jiqiu , Trivieri Maria G , Singh Rajvir , Mayr Manuel , Fish Kenneth , Lebeche Djamel , Hajjar Roger J , Sahoo Susmita
Published: February 2019

Background:
Despite its functional importance in various fundamental bioprocesses, the studies of N6-methyladenosine (m6A) in the heart are lacking. In this study, we investigated the role of fat mass and obesity-associated (FTO), an m6A demethylase, in cardiac contractile function during homeostasis and remodeling.

Methods:
We used clinical human samples, preclinical pig and mouse models and primary cardiomyocyte cell cultures to study the functional role of m6A and FTO in the heart and in cardiomyocytes. We modulated expression of FTO using AAV9 (in vivo), adenovirus (both in vivo and in vitro) and siRNAs (in vitro). We performed methylated (m6A) RNA immunoprecipitation sequencing (MeRIP-seq) to map transcriptome-wide m6A, and MeRIP qPCR assays to map and validate m6A in individual transcripts, in healthy and failing hearts and myocytes. We performed proteomics analysis using stable isotope labeling with amino acids in cell culture to study m6A role in mRNA to protein translation.

Results:
We discovered that FTO has decreased expression in failing mammalian hearts and hypoxic cardiomyocytes, thereby increasing m6A in RNA and decreasing cardiomyocyte contractile function. Improving expression of FTO in failing mouse hearts attenuated the ischemia-induced increase in m6A and decrease in cardiac contractile function. This is carried out by the demethylation activity of FTO, which selectively demethylates cardiac contractile transcripts, thus preventing their degradation and improving their protein expression under ischemia.

Conclusion:
Collectively, our study demonstrates the functional importance of FTO-dependent cardiac m6A methylome in cardiac contraction during heart failure and provides a novel mechanistic insight into the therapeutic mechanisms of FTO.
Abstract 585: CDK8 Activity-dependent Regulation of Heart Disease
Authors: Minerath Rachel , Vaske Allison , Hall Duane , Grueter Chad
Published: February 2019

Pathological cardiac hypertrophy represents a major risk factor for heart failure (HF). The hypertrophic response is orchestrated in part through transcriptional alterations that ultimately modify cardiac function. Mediator is a multiprotein complex that coordinates signal dependent transcription factors with basal transcriptional machinery including RNA polymerase II and general transcription factors. Transcriptional regulation by Mediator complex can be modified by the association of the Mediator complex kinase submodule with the core complex. Cyclin-dependent kinase 8 (CDK8) is a kinase present in the submodule that has been demonstrated to have a complex role in transcriptional regulation through a number of mechanisms involving both transcriptional activation and inhibition. Our lab has demonstrated that CDK8 expression is upregulated in murine HF models as well as in failing human hearts. In addition, cardiac CDK8 over-expression promotes transcriptional remodeling that results in dilated cardiomyopathy suggesting that CDK8 inhibition may represent a novel pharmacological target. This study utilizes CDK8 kinase inhibitor, Senexin A, which is being evaluated as an anti-cancer chemotherapeutic agent. Here, we demonstrate that Senexin A inhibits kinase activity in an
in vitro
neonatal rat cardiomyocyte (NRCM) model resulting in reduced cardiomyocyte hypertrophy as well as a reduction in expression of specific cardiomyocyte hypertrophy markers. These studies demonstrate a role for CDK8 activity in transcriptional regulation of genes associated with pathological cardiac remodeling that drives cardiac hypertrophy and ultimately HF.
WEAVE Trial
Authors: Alexander Michael J. , Zauner Alois , Chaloupka John C. , Baxter Blaise , Callison Richard C. , Gupta Rishi , Song Shlee S. , Yu Wengui ,   on behalf of the WEAVE Trial Investigators, Feng Lei , Bonovich David , Toth Gabor , Kott Brian , Veznedaroglu Erol , Ringer Andrew , Meyers Philip , Agola John , Ghodke Basavaraj , Alhajeri Abdulnasser , Fraser Justin , Given Curtis , de Valle Eric Lopez , Shah Qaisar , Nesbit Gary , Hassan Ameer , Grobelny Thomas , Fessler Richard , Shownkeen Harish
Published: February 2019

Background and Purpose—

The WEAVE trial (Wingspan Stent System Post Market Surveillance) is a postmarket surveillance trial mandated by the Food and Drug Administration to assess the periprocedural safety of the Wingspan Stent system in the treatment of symptomatic intracranial atherosclerotic disease.

Methods—

A total of 152 consecutive patients who met the Food and Drug Administration on-label usage criteria were enrolled at 24 hospitals and underwent angioplasty and stenting with the Wingspan stent. On-label criteria included age 22 to 80 years, symptomatic intracranial atherosclerotic stenosis of 70% to 99%, baseline modified Rankin Scale score ≤3, ≥2 strokes in the vascular territory of the stenotic lesion with at least 1 stroke while on medical therapy, and stenting of the lesion ≥8 days after the last stroke. The primary analysis assessed the periprocedural stroke, bleed, and death rate within 72 hours of the procedure with adjudication by a core study Stroke Neurologist.

Results—

The trial was stopped early after interim analysis of 152 consecutive patients demonstrated a lower than expected 2.6% (4/152 patients) periprocedural stroke, bleed, and death rate. This was lower than the 4% periprocedural primary event safety benchmark set for the interim analysis in the study. A total of 97.4% (148/152) patients were event-free at 72 hours, 1.3% (2/152) had nonfatal strokes, and 1.3% (2/152) of patients died.

Conclusions—

With experienced interventionalists, and proper patient selection following the on-label usage guidelines, the use of the Wingspan stent for intracranial atherosclerotic disease demonstrated a low periprocedural complication rate and excellent safety profile. This is the largest on-label, multicenter, prospective trial of the Wingspan stent system to date with the lowest reported complication rate.

Clinical Trial Registration—

URL:
https://www.clinicaltrials.gov
. Unique identifier: NCT02034058.
A Tandem Evolutionary Algorithm for Identifying Causal Rules from Complex
Data
Authors: Hanley John P. , Rizzo Donna M. , Buzas Jeffrey S. , Eppstein Margaret J.
Published: February 2019

We propose a new evolutionary approach for discovering causal rules in complex classification problems from batch data. Key aspects include (a) the use of a hypergeometric probability mass function as a principled statistic for assessing fitness that quantifies the probability that the observed association between a given clause and target class is due to chance, taking into account the size of the dataset, the amount of missing data, and the distribution of outcome categories, (b) tandem age-layered evolutionary algorithms for evolving parsimonious archives of conjunctive clauses, and disjunctions of these conjunctions, each of which have probabilistically significant associations with outcome classes, and (c) separate archive bins for clauses of different orders, with dynamically adjusted order-specific thresholds. The method is validated on majority-on and multiplexer benchmark problems exhibiting various combinations of heterogeneity, epistasis, overlap, noise in class associations, missing data, extraneous features, and imbalanced classes. We also validate on a more realistic synthetic genome dataset with heterogeneity, epistasis, extraneous features, and noise. In all synthetic epistatic benchmarks, we consistently recover the true causal rule sets used to generate the data. Finally, we discuss an application to a complex real-world survey dataset designed to inform possible ecohealth interventions for Chagas disease.
The first chinch bug Blissidae (Hemiptera, Heteroptera) from the Eocene Oise amber

Authors: GARROUSTE ROMAIN , SCHUBNEL THOMAS , NEL ANDRÉ
Published: February 2019

Eoblissus gallicus gen. et sp. nov., first accurate fossil Blissidae, is described from the Lowermost Eocene amber of France. This fossil is of interest for future calibrations regarding phylogenetic dating of the Lygaeoidea.
Three new minute nematode species of the superfamily Monhysteroidea from Arctic Abyss
Authors: TCHESUNOV ALEXEI V. , MILJUTINA MARIA A.
Published: February 2019

Three new nematode species of the superfamily Monhysteroidea were found in the Molloy Deep (Fram Strait, Arctic Ocean) at depths of > 5000 m. Amphimonhystrella bullacauda sp. n. (Xyalidae) is similar to A. unita Lorenzen 1977 but differs from it by having longer cephalic setae (1.5–3.5 versus 1.0 µm), lacking cervical setae, head set off from the body, singular anterior testis, distally pointed spicules, larger protuberant terminal tail widening. The generic diagnosis of Amphimonhystrella Timm 1961 is amended, and a dichotomous key for identification of the three Amphimonhystrella species is provided. Thalassomonhystera oxycephalata sp. n. (Monhysteridae) is distinguished from all valid Thalassomonhystera species by a number of morphological characters including narrowed cephalic end, wide amphid, short tubular weakly sclerotised stoma, esophagus gradually widening posteriorly, lacking evident renette cell, short arcuate spicules and gubernaculum with small dorsocaudal apophysis, tail with slender cylindrical portion distinctly set off. Thalassomonhystera molloyensis sp. n. is related to T. bathislandica Riemann 1995 described also from the north-eastern Atlantic abyssal but differs by having: 1) smaller body, male length 392–460 µm versus 572–684 µm, female length 376–472 µm versus 615–633 µm; 2) sclerotised lips of vulva; 3) presense of two ventral papillae or pairs of papillae, first pair in preanal position and second pair in postanal position just behind the middle of the tail. It is noteworthy that in both species the male genital tract has a variable position in relation to the intestine which is a deviation from the normal monhysterid morphology.
Austrolebias univentripinnis sp. nov. (Teleostei: Cyprinodontiformes: Rivulidae): a new annual killifish from the Mirim Lagoon basin, southern Brazil
Authors: COSTA WILSON J.E.M. , CHEFFE MOREVY M.
Published: February 2019

Austrolebias univentripinnis n. sp. is described from the Jaguarão River floodplains, Mirim Lagoon basin, southern Brazil. It is a member of a clade that also includes A. viarius, A. arachan, A. adloffi, A. charrua, A. minuano, A. nigrofasciatus, A. vandenbergi, A. bellottii, and A. melanoorus, which is diagnosed by the possession of a long and triangular anal fin in females. The new species is similar to A. bellottii and A. melanoorus in having the urogenital papilla completely attached to the anal fin in males; it differs from A. bellottii in having the dorsal fin more anteriorly placed in males, a shorter anal-fin base, lesser body depth, and wider basihyal; it is distinguished from A. melanoorus by the number of rostral neuromasts, degree of pelvic-fin fusion, morphology of dorsum in females, color pattern of unpaired fins in males, and color pattern of flank in both sexes.
Some tardigrades from Siberia (Russia, Baikal region) with a description of Macrobiotus garynahi sp. nov. (Eutardigrada: Macrobiotidae: richtersi group)
Authors: KACZMAREK ŁUKASZ , MICHALCZYK ŁUKASZ , DIDUSZKO DAWID
Published: February 2019

A new species, Macrobiotus garynahi sp. nov. is described from a lichen sample collected in the Baikal region (Russia). The new species belongs to the richtersi group and it is most similar to M. vanescens Pilato et al., 1991 and M. alekseevi Tumanov, 2005. The new species differs from M. vanescens by the presence of more evident microplacoid, different shape of egg processes and shorter claws. M. garynahi sp. nov. differs from M. alekseevi by the presence of granulation on all legs, different oral cavity armature, generally larger body size and different shape of egg processes. Also in this paper, another seven Tardigrada species are reported from Siberia (Russia). One of them, Macrobiotus crenatus Maucci is new to this region and this is also the first record of this species other than Greenland (type locality).
Five new species of Diptilomiopidae from China (Acari: Eriophyoidea)
Authors: XUE XIAO-FENG , HONG X.-Y.
Published: February 2019

Five new species of diptilomipid eriophyoid mites from China are described and illustrated: Rhyncaphytoptus longipalpis sp. nov. on Bambusa sp. (Gramineae); Rhyncaphytoptus taihangensis sp. nov. on Morus alba L.(Moraceae); Rhyncaphytoptus papyriferae sp. nov. on Broussonetia papyrifera (L.) Vent. (Moraceae); Diptacus songxianensis sp. nov. on Ulmus sp.(Ulmaceae) and Trimeroptes luanchuanensis sp. nov. on Rubus sp. (Rosaceae). All species described here are vagrant on leaves.