Signaling In Cardiomyocytes Research Articles

Retinol-Binding Protein 4 Promotes Cardiac Injury After Myocardial Infarction Via Inducing Cardiomyocyte Pyroptosis Through an Interaction With NLRP3.

BackgroundAcute myocardial infarction (AMI) is one of the leading causes of cardiovascular morbidity and mortality worldwide. Pyroptosis is a form of inflammatory cell death that plays a major role in the development and progression of cardiac injury in AMI. However, the underlying mechanisms for the activation of pyroptosis during AMI are not fully elucidated.Methods and ResultsHere we show that RBP4 (retinol‐binding protein 4), a previous identified proinflammatory adipokine, was increased both in the myocardium of left anterior descending artery ligation‐induced AMI mouse model and in ischemia‐hypoxia‒induced cardiomyocyte injury model. The upregulated RBP4 may contribute to the activation of cardiomyocyte pyroptosis in AMI because overexpression of RBP4 activated NLRP3 (nucleotide‐binding oligomerization domain‐like receptor family pyrin domain‐containing 3) inflammasome, promoted the precursor cleavage of Caspase‐1, and subsequently induced GSDMD (gasdermin‐D)‐dependent pyroptosis. In contrast, knockdown of RBP4 alleviated ischemia‐hypoxia‒induced activation of NLRP3 inflammasome signaling and pyroptosis in cardiomyocytes. Mechanistically, coimmunoprecipitation assay showed that RBP4 interacted directly with NLRP3 in cardiomyocyte, while genetic knockdown or pharmacological inhibition of NLRP3 attenuated RBP4‐induced pyroptosis in cardiomyocytes. Finally, knockdown of RBP4 in heart decreased infarct size and protected against AMI‐induced pyroptosis and cardiac dysfunction in mice.ConclusionsTaken together, these findings reveal RBP4 as a novel modulator promoting cardiomyocyte pyroptosis via interaction with NLRP3 in AMI. Therefore, targeting cardiac RBP4 might represent a viable strategy for the prevention of cardiac injury in patients with AMI.

Transcriptome aberration associated with altered locomotor behavior of zebrafish (Danio rerio) caused by Waterborne Benzo[a]pyrene

Waterborne Benzo[a]pyrene (B[a]P) pollution is a global threat to aquatic organisms. The exposure to waterborne B[a]P can disrupt the normal locomotor behavior of zebrafish (Danio rerio), however, how it affect the locomotor behavior of adult zebrafish remains unclear. Herein, B[a]P at two concentrations (0.8 μg/L and 2.0 μg/L) were selected to investigate the molecular mechanisms of the affected locomotor behavior of zebrafish by B[a]P based on transcriptome profiling. Adverse effects of B[a]P exposure affecting locomotor behavior in zebrafish were studied by RNA sequencing, and the locomotion phenotype was acquired. The gene enrichment results showed that the differentially highly expressed genes (atp2a1, cdh2, aurka, fxyd1, clstn1, apoc1, mt-co1, tnnt3b, and fads2) of zebrafish are mainly enriched in adrenergic signaling in cardiomyocytes (dre04261) and locomotory behavior (GO:0007626). The movement trajectory plots showed an increase in the locomotor distance and velocity of zebrafish in the 0.8 μg/L group and the opposite in the 2.0 μg/L group. The results showed that B[a]P affects the variety of genes in zebrafish, including motor nerves, muscles, and energy supply, and ultimately leads to altered locomotor behavior.

Health risks of sulfentrazone exposure during zebrafish embryo-larvae development at environmental concentration

Knowledge about the negative effects and mechanism of sulfentrazone (SUL) on aquatic early life stages is still limited. Here we investigated the lethal and sub-lethal effects of SUL during zebrafish embryo-larvae development. Results demonstrated that the 96 h and 120 h-LC50 of SUL to embryonic zebrafish was 2.02 mg/L, and the 30 d-LC50 was 0.899 mg/L after embryos exposed to SUL for 30 d. High concentrations of SUL delayed yolk sac absorption, disordered the hatching and heart rate during zebrafish embryonic stage, while 0.0100–0.100 mg/L SUL had no phenotypic changes on embryonic development, but decreased the body weight of larvae after 30 d exposure. RNA-seq identified 321, 394 and 727 differentially expressed genes in larvae after embryos exposed to 0.0100 mg/L, 0.0400 mg/L and 0.400 mg/L SUL for 30 d, found that the transcriptional profiles involved in heart development and endocrine disruption were simultaneously influenced by different concentrations of SUL, such as adrenergic signaling in cardiomyocytes, cardiac muscle contraction, cell adhesion molecules and steroid biosynthesis. Biochemical analysis showed that SUL increased the levels of E2, T3 and TSH, induced the activities of mitochondrial complex IV, cytochrome c oxidase, Ca2+-ATPase, total Na+K+-ATPase and Ca2+Mg2+-ATPase, and decreased ATP formation after embryos exposed to SUL for 5 d and 30 d. Further comprehensive analysis demonstrated that SUL caused more significantly alteration on the transcript, level or activity of the key elements involved in heart development and endocrine disruption after 30 d exposure, indicated long-term SUL exposure might cause more negative effects on zebrafish at doses below the presumed no-observed-adverse-effect level during early life development. The results inferred the environmental concentration of SUL might cause potential cardiac and endocrine health risk in zebrafish later life stages, also facilitated a better understanding of the sub-lethal effects and molecular mechanism of SUL on aquatic organism.

Alterations in ACE and ACE2 Activities and Cardiomyocyte Signaling Underlie Improved Myocardial Function in a Rat Model of Repeated Remote Ischemic Conditioning.

Post-ischemic left ventricular (LV) remodeling and its hypothetical prevention by repeated remote ischemic conditioning (rRIC) in male Sprague–Dawley rats were studied. Myocardial infarction (MI) was evoked by permanent ligation of the left anterior descending coronary artery (LAD), and myocardial characteristics were tested in the infarcted anterior and non-infarcted inferior LV regions four and/or six weeks later. rRIC was induced by three cycles of five-minute-long unilateral hind limb ischemia and five minutes of reperfusion on a daily basis for a period of two weeks starting four weeks after LAD occlusion. Sham operated animals served as controls. Echocardiographic examinations and invasive hemodynamic measurements revealed distinct changes in LV systolic function between four and six weeks after MI induction in the absence of rRIC (i.e., LV ejection fraction (LVEF) decreased from 52.8 ± 2.1% to 50 ± 1.6%, mean ± SEM, p < 0.05) and in the presence of rRIC (i.e., LVEF increased from 48.2 ± 4.8% to 55.2 ± 4.1%, p < 0.05). Angiotensin-converting enzyme (ACE) activity was about five times higher in the anterior LV wall at six weeks than that in sham animals. Angiotensin-converting enzyme 2 (ACE2) activity roughly doubled in post-ischemic LVs. These increases in ACE and ACE2 activities were effectively mitigated by rRIC. Ca2+-sensitivities of force production (pCa50) of LV permeabilized cardiomyocytes were increased at six weeks after MI induction together with hypophosphorylation of 1) cardiac troponin I (cTnI) in both LV regions, and 2) cardiac myosin-binding protein C (cMyBP-C) in the anterior wall. rRIC normalized pCa50, cTnI and cMyBP-C phosphorylations. Taken together, post-ischemic LV remodeling involves region-specific alterations in ACE and ACE2 activities together with changes in cardiomyocyte myofilament protein phosphorylation and function. rRIC has the potential to prevent these alterations and to improve LV performance following MI.

Activation of GPER limits adverse changes to Ca2+ signalling and arrhythmogenic activity in cardiomyocytes of ovariectomised guinea pigs

Abstract Background Post-menopausal women have an enhanced risk of developing cardiovascular disease and disturbances of cardiac rhythm, generally attributed to declining oestrogen levels during menopause. In an animal model that mimics menopause, the long-term withdrawal of oestrogen dysregulated Ca2+ signalling and increased the formation of a pro-arrhythmic substrate. Selective targeting of the membrane bound G-protein coupled oestrogen receptor 1 (GPER) eliminated such arrhythmogenic activity associated with the loss of oestrogen. Purpose We aim to assess the “cardioprotective” role of GPER in response to oestrogen withdrawal. Methods Ovariectomy (OVx) or sham surgeries were conducted on female guinea pigs. Left ventricular cardiomyocytes were isolated 150-days post-operatively for experimental use. GPER expression was quantified by western blot. Myocytes were incubated in solutions containing GPER agonist G-1 for &amp;gt;2h before recording some electrophysiological and Ca2+ regulatory parameters. Results GPER expression was 32% higher in OVx. OVx cardiomyocytes had prolonged action potential duration (APD) compared with sham and in the presence of G-1, APD90 shortened by 12% and 22% in sham and OVx, respectively. G-1 reduced early after depolarisation (EAD) formation by &amp;gt;99% in OVx. OVx cells had larger sarcoplasmic reticulum (SR) Ca2+ content (by 13%), compared with sham. While G-1 had little effect on SR content, it reduced Ca2+ transient amplitude (by 40%), SR fractional release (by 11%) and sarcomere shortening (by 29%) in OVx cells. The frequency of occurrence of spontaneous Ca2+ waves evoked by periods of rapid stimulation reduced by 40% and wave-free survival time prolonged in OVx cells incubated with G-1. Conclusions In the hearts of an animal species whose electrophysiology and intracellular Ca2+ regulation is akin to humans, we show that following oestrogen deficiency, GPER expression increased and its activation induces negative inotropic responses in cardiomyocytes. It limits the adverse changes to Ca2+ signalling and induces anti-arrhythmogenic behaviours in OVx. Funding Acknowledgement Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): British Heart Foundation

Retinoic acid signaling is directly activated in cardiomyocytes and protects mouse hearts from apoptosis after myocardial infarction.

Retinoic acid (RA) is an essential signaling molecule for cardiac development and plays a protective role in the heart after myocardial infarction (MI). In both cases, the effect of RA signaling on cardiomyocytes, the principle cell type of the heart, has been reported to be indirect. Here we have developed an inducible murine transgenic RA-reporter line using CreERT2 technology that permits lineage tracing of RA-responsive cells and faithfully recapitulates endogenous RA activity in multiple organs during embryonic development. Strikingly, we have observed a direct RA response in cardiomyocytes during mid-late gestation and after MI. Ablation of RA signaling through deletion of the Aldh1a1/a2/a3 genes encoding RA-synthesizing enzymes leads to increased cardiomyocyte apoptosis in adults subjected to MI. RNA sequencing analysis reveals Tgm2 and Ace1, two genes with well-established links to cardiac repair, as potential targets of RA signaling in primary cardiomyocytes, thereby providing novel links between the RA pathway and heart disease.

Samm50 Promotes Hypertrophy by Regulating Pink1-Dependent Mitophagy Signaling in Neonatal Cardiomyocytes.

Pathological cardiac hypertrophy, the adaptive response of the myocardium to various pathological stimuli, is one of the primary predictors and predisposing factors of heart failure. However, its molecular mechanisms underlying pathogenesis remain poorly understood. Here, we studied the function of Samm50 in mitophagy during Ang II-induced cardiomyocyte hypertrophy via lentiviruses mediated knockdown and overexpression of Samm50 protein. We first found that Samm50 is a key positive regulator of cardiac hypertrophy, for western blot and real-time quantitative PCR detection revealed Samm50 was downregulated both in pressure-overload-induced hypertrophic hearts and Ang II-induced cardiomyocyte hypertrophy. Then, Samm50 overexpression exhibits enhanced induction of cardiac hypertrophy marker genes and cell enlargement in primary mouse cardiomyocytes by qPCR and immunofluorescence analysis, respectively. Meanwhile, Samm50 remarkably reduced Ang II-induced autophagy as indicated by decreased mitophagy protein levels and autophagic flux, whereas the opposite phenotype was observed in Samm50 knockdown cardiomyocytes. However, the protective role of Samm50 deficiency against cardiac hypertrophy was abolished by inhibiting mitophagy through Vps34 inhibitor or Pink1 knockdown. Moreover, we further demonstrated that Samm50 interacted with Pink1 and stimulated the accumulation of Parkin on mitochondria to initiate mitophagy by co-immunoprecipitation analysis and immunofluorescence. Thus, these results suggest that Samm50 regulates Pink1-Parkin-mediated mitophagy to promote cardiac hypertrophy, and targeting mitophagy may provide new insights into the treatment of cardiac hypertrophy.

Abstract P379: Inhibition Of O-glcnac Transferase Ogt Activates P38 Signaling In Neonatal Rat Cardiomyocytes

The mitogen activated protein kinase (MAPK) p38 is important in cardiac hypertrophic responses and p38 inhibition has been tested as a potential therapeutic approach to heart failure. p38 is tightly regulated by upstream kinases and phosphatases. While p38 inhibitors suppress cardiac hypertrophy in vitro and in animal models, the partial efficacy of p38 inhibitors in clinical trials for heart failure illustrates the need for a deeper understanding of p38-regulatory mechanisms. O -linked N-Acetylglucosamine ( O -GlcNAc) on Ser/Thr residues is a ubiquitous intracellular modification ( O -GlcNAcylation) that participates in intracellular signaling, often occurring in counterpoint to phosphorylation. O -GlcNAcylation is catalyzed by O -GlcNAc Transferase (OGT) and removed by O -GlcNAc-Ase (OGA). Given the crucial regulation of p38 activity by phosphorylation, we hypothesized that O -GlcNAcylation regulates p38 phosphorylation during basal and hypertrophic cardiomyocyte signaling. Treating neonatal rat ventricular myocytes (NRVM) with OSMI-1 (inhibitor of OGT) significantly decreased O -GlcNAcylation (0.48 ± 0.02, P &lt;0.001 vs. vehicle), whereas treatment with Thiamet-G (inhibitor of OGA) significantly increased O -GlcNAcylation (3.0-fold increase ± 0.35, P &lt;0.05 vs. vehicle). OSMI1 treatment induced the phosphorylation of p38 at its activation site (3.9-fold increase ± 0.46, P &lt;0.001 vs. vehicle) and promoted the phosphorylation of the downstream target, heat shock protein Hsp27 (8-fold increase ± 1.3, P &lt;0.0001 vs. vehicle) and transcription factor Creb (3.3-fold increase ± 0.12, P &lt;0.001 vs. vehicle). OSMI-1 had an additive effect in inducing p38 and Creb phosphorylation following hypertrophic stimulation by phenylephrine (3.1-fold and 1.4-fold increase vs. phenylephrine respectively, P &lt;0.05). Treatment with the p38 inhibitor SB202190 abolished the phosphorylation of Hsp27 and Creb that was induced by OSMI-1. Canonical upstream activators of p38 include the MAP3Ks, TAK1 and ASK1. However, we found that treatment with ASK1 or TAK1 inhibitors (GS-444217 and Takinib, respectively) either alone, or in combination, did not negate the phosphorylation of p38 by OSMI-1. We conclude that regulation of p38 by OGT activity could occur at a level downstream of canonical MAP3Ks or through non-canonical pathways.

Fibrosis of the diabetic heart: Clinical significance, molecular mechanisms, and therapeutic opportunities.

In patients with diabetes, myocardial fibrosis may contribute to the pathogenesis of heart failure and arrhythmogenesis, increasing ventricular stiffness and delaying conduction. Diabetic myocardial fibrosis involves effects of hyperglycemia, lipotoxicity and insulin resistance on cardiac fibroblasts, directly resulting in increased matrix secretion, and activation of paracrine signaling in cardiomyocytes, immune and vascular cells, that release fibroblast-activating mediators. Neurohumoral pathways, cytokines, growth factors, oxidative stress, advanced glycation end-products (AGEs), and matricellular proteins have been implicated in diabetic fibrosis; however, the molecular links between the metabolic perturbations and activation of a fibrogenic program remain poorly understood. Although existing therapies using glucose- and lipid-lowering agents and neurohumoral inhibition may act in part by attenuating myocardial collagen deposition, specific therapies targeting the fibrotic response are lacking. This review manuscript discusses the clinical significance, molecular mechanisms and cell biology of diabetic cardiac fibrosis and proposes therapeutic targets that may attenuate the fibrotic response, preventing heart failure progression.

A network pharmacology study with molecular docking to investigate the possibility of licorice against posttraumatic stress disorder.

Post traumatic stress disorder (PTSD) is a mental health condition that has a debilitating effect on a person's quality of life and leads to a high socioeconomic burden. Licorice has been demonstrated to have neuroprotective and antidepressant-like effects, but little is known about its effects for the treatment of PTSD. The present study aimed to explore the potential of licorice for PTSD therapy using a network pharmacology approach with molecular docking studies. The compounds of licorice were obtained from databases with screening by absorption, distribution, metabolism and excretion (ADME) evaluation. Genes associated with compounds or PTSD were obtained from public databases, and the genes overlapping between licorice compounds and PTSD were compared by Venn diagram. A network of medicine-ingredients-targets-disease was constructed, visualized, and analyzed using cytoscape software. Protein-protein interactions, gene ontology, pathway enrichment and molecular docking were performed to evaluate the effect of licorice for the treatment of PTSD. 69 potential compounds were screened after ADME evaluation. A total of 81 compound-related genes and 566 PTSD-related genes were identified in the databases with 27 overlapping genes. Licorice compounds (e.g., medicarpin, 7-methoxy-2-methyl isoflavone, shinpterocarpin, formononetin, licochalcone a) and target proteins (e.g., ESR1, PTGS2, NOS2, and ADRB2) with high degree in the network were involved in G protein-coupled receptor signaling pathways at the postsynaptic/synaptic membrane. Moreover, neuroactive ligand-receptor interactions, calcium signaling, cholinergic synapse, serotonergic synapse and adrenergic signaling in cardiomyocytes may play important roles in the treatment of PTSD by licorice. This study provides molecular evidence of the beneficial effects of licorice for the treatment of PTSD.

Polycystin-1 is required for insulin-like growth factor 1-induced cardiomyocyte hypertrophy.

Cardiac hypertrophy is the result of responses to various physiological or pathological stimuli. Recently, we showed that polycystin-1 participates in cardiomyocyte hypertrophy elicited by pressure overload and mechanical stress. Interestingly, polycystin-1 knockdown does not affect phenylephrine-induced cardiomyocyte hypertrophy, suggesting that the effects of polycystin-1 are stimulus-dependent. In this study, we aimed to identify the role of polycystin-1 in insulin-like growth factor-1 (IGF-1) signaling in cardiomyocytes. Polycystin-1 knockdown completely blunted IGF-1-induced cardiomyocyte hypertrophy. We then investigated the molecular mechanism underlying this result. We found that polycystin-1 silencing impaired the activation of the IGF-1 receptor, Akt, and ERK1/2 elicited by IGF-1. Remarkably, IGF-1-induced IGF-1 receptor, Akt, and ERK1/2 phosphorylations were restored when protein tyrosine phosphatase 1B was inhibited, suggesting that polycystin-1 knockdown deregulates this phosphatase in cardiomyocytes. Moreover, protein tyrosine phosphatase 1B inhibition also restored IGF-1-dependent cardiomyocyte hypertrophy in polycystin-1-deficient cells. Our findings provide the first evidence that polycystin-1 regulates IGF-1-induced cardiomyocyte hypertrophy through a mechanism involving protein tyrosine phosphatase 1B.

Silencing Survivin: a Key Therapeutic Strategy for Cardiac Hypertrophy.

Cardiac hypertrophy, in its aspects of localized thickening of the interventricular septum and concentric increase of the left ventricle, constitutes a risk factor of heart failure. Myocardial hypertrophy, in the presence of different degree of myocardial fibrosis, is paralleled by significant molecular, cellular, and histological changes inducing alteration of cardiac extracellular matrix composition as well as sarcomeres and cytoskeleton remodeling. Previous studies indicate osteopontin (OPN) and more recently survivin (SURV) overexpression as the hallmarks of heart failure although SURV function in the heart is not completely clarified. In this study, we investigated the involvement of SURV in intracellular signaling of hypertrophic cardiomyocytes and the impact of its transcriptional silencing, laying the foundation for novel target gene therapy in cardiac hypertrophy. Oligonucleotide-based molecules, like theranostic optical nanosensors (molecular beacons) and siRNAs, targeting SURV and OPN mRNAs, were developed. Their diagnostic and therapeutic potential was evaluated in vitro in hypertrophic FGF23-induced human cardiomyocytes and in vivo in transverse aortic constriction hypertrophic mouse model. Engineered erythrocyte was used as shuttle to selectively target and transfer siRNA molecules into unhealthy cardiac cells in vivo. The results highlight how the SURV knockdown could negatively influence the expression of genes involved in myocardial fibrosis in vitro and restores structural, functional, and morphometric features in vivo. Together, these data suggested that SURV is a key factor in inducing cardiomyocytes hypertrophy, and its shutdown is crucial in slowing disease progression as well as reversing cardiac hypertrophy. In the perspective, targeted delivery of siRNAs through engineered erythrocytes can represent a promising therapeutic strategy to treat cardiac hypertrophy. Theranostic SURV molecular beacon (MB-SURV), transfected into FGF23-induced hypertrophic human cardiomyocytes, significantly dampened SURV overexpression. SURV down-regulation determines the tuning down of MMP9, TIMP1 and TIMP4 extracellular matrix remodeling factors while induces the overexpression of the cardioprotective MCAD factor, which counterbalance the absence of pro-survival and anti-apoptotic SURV activity to protect cardiomyocytes from death. In transverse aortic constriction (TAC) mouse model, the SURV silencing restores the LV mass levels to values not different from the sham group and counteracts the progressive decline of EF, maintaining its values always higher with respect to TAC group. These data demonstrate the central role of SURV in the cardiac reverse remodeling and its therapeutic potential to reverse cardiac hypertrophy.

Proline hydroxylase domain-containing enzymes regulate calcium levels in cardiomyocytes by TRPA1 ion channel

The proline hydroxylase domain-containing enzymes (PHDs) acts as cellular oxygen sensors, inducing a series of responses to hypoxia, especially during the regulation of metabolism and energy homeostasis. The increase of Ca2+ in cardiomyocytes, induced by the opening of PHD signaling pathway, is the key initiation signal necessary for the PHD-mediated regulation of the energy metabolism pathway, but the underlying molecular mechanism remains incompletely understood. This study used PHD inhibitors (PHIs) and PHD2-specific RNA interference (PHD2shRNA) to inhibit PHD signals in cardiomyocytes to explore whether transient receptor potential ankyrin 1 (TRPA1) is involved in the regulation of calcium ion influx in the PHD activation pathway associated with to AMP-activated protein kinase (AMPK). The Fluo-3AM probe was used to measure changes in free intracellular calcium ion concentrations, and Western blot analysis was used to detect the levels of phosphorylated (P)-AMPK, TRPA1, and P–Ca2+/calmodulin-dependent protein kinase Ⅱ (CaMKⅡ) levels. The PHI-mediated inhibition of PHD resulted in an increase in free Ca2+ fluorescence in cardiomyocytes, which activated AMPK, TRPA1, and CaMKⅡ. The TRPA1 inhibitor HC030031, the CaMKII inhibitor KN93, and a ryanodine inhibitor (Ryanodine) were all able to inhibit the PHI-induced increase in intracellular Ca2+ and AMPK activation. Both PHIs and PHD2shRNA were able to effectively activate CaMKII and TRPA1. However, an inositol 1,4,5-triphosphate receptor (IP3R) inhibitor and the protein kinase A (PKA) inhibitor H89 did not significantly inhibit the PHI-induced increase in intracellular Ca2+ and AMPK activation. These results indicated that PHD might activate the CaMKⅡ pathway through the TRPA1 ion channel, inducing the release of calcium from the sarcoplasmic reticulum through ryanodine receptor 2 (RyR2), activating AMPK to initiate the protective effects of hypoxia in cardiomyocytes.

A chromosome-level genome assembly of Cairina moschata and comparative genomic analyses

BackgroundThe Muscovy duck (Cairina moschata) is an economically important duck species, with favourable growth and carcass composition parameters in comparison to other ducks. However, limited genomic resources for Muscovy duck hinder our understanding of its evolution and genetic diversity.ResultsWe combined linked-reads sequencing technology and reference-guided methods for de novo genome assembly. The final draft assembly was 1.12 Gbp with 29 autosomes, one sex chromosome and 4,583 unlocalized scaffolds with an N50 size of 77.35 Mb. Based on universal single-copy orthologues (BUSCO), the draft genome assembly completeness was estimated to be 93.30 %. Genome annotation identified 15,580 genes, with 15,537 (99.72 %) genes annotated in public databases. We conducted comparative genomic analyses and found that species-specific and rapidly expanding gene families (compared to other birds) in Muscovy duck are mainly involved in Calcium signaling, Adrenergic signaling in cardiomyocytes, and GnRH signaling pathways. In comparison to the common domestic duck (Anas platyrhynchos), we identified 104 genes exhibiting strong signals of adaptive evolution (Ka/Ks > 1). Most of these genes were associated with immune defence pathways (e.g. IFNAR1 and TLR5). This is indicative of the existence of differences in the immune responses between the two species. Additionally, we combined divergence and polymorphism data to demonstrate the “faster-Z effect” of chromosome evolution.ConclusionsThe chromosome-level genome assembly of Muscovy duck and comparative genomic analyses provide valuable resources for future molecular ecology studies, as well as the evolutionary arms race between the host and influenza viruses.

Hybrid Integrated Cardiomyocyte Biosensors for Bitter Detection and Cardiotoxicity Assessment.

Among basic taste sensations, bitter taste is vital to the survival of mammals due to its indispensable role in toxin prediction or identification, so the identification of bitter compounds is of great value in the pharmaceutical and food industry. Recently, bitter taste receptor (T2Rs)-based biosensors have been developed for specific bitter detection. However, the taste biosensors based on taste cells/tissues suffer from simple function, low sensitivity, low content, and limited parameters. Here, to establish a high-content, highly sensitive, and multifunctional taste biosensor, we developed a multifunctional hybrid integrated cardiomyocyte biosensor (HICB) for bitter detection. Due to the expression of bitter taste receptors in cardiomyocytes, the HICB can recognize the specific bitter agonists by synchronously recording the extracellular field potential (EFP) and mechanical beating (MB) signals from the cultured cardiomyocytes in vitro. Multiple feature parameters were defined and extracted from the electromechanical signals of cardiomyocytes to analyze the specific responses to four typical bitter compounds. The radar map, heat map, and principal component analysis (PCA) were used to visualize and classify the specific responses. Moreover, bitter-induced cardiotoxicity also was chronically evaluated, and these bitter compounds presented an inhibition effect on the electrophysiological and contractile activities of cardiomyocytes. This high-content HICB offers an alternative platform for both bitter detection and cardiotoxicity assessment, showing promising applications in the fields of taste detection and toxicity screening.

RhoA Signaling in Immune Cell Response and Cardiac Disease.

Chronic inflammation, the activation of immune cells and their cross-talk with cardiomyocytes in the pathogenesis and progression of heart diseases has long been overlooked. However, with the latest research developments, it is increasingly accepted that a vicious cycle exists where cardiomyocytes release cardiocrine signaling molecules that spiral down to immune cell activation and chronic state of low-level inflammation. For example, cardiocrine molecules released from injured or stressed cardiomyocytes can stimulate macrophages, dendritic cells, neutrophils and even T-cells, which then subsequently increase cardiac inflammation by co-stimulation and positive feedback loops. One of the key proteins involved in stress-mediated cardiomyocyte signal transduction is a small GTPase RhoA. Importantly, the regulation of RhoA activation is critical for effective immune cell response and is being considered as one of the potential therapeutic targets in many immune-cell-mediated inflammatory diseases. In this review we provide an update on the role of RhoA at the juncture of immune cell activation, inflammation and cardiac disease.

IGF-1 protects against angiotensin II-induced cardiac fibrosis by targeting \u03b1SMA

The insulin-like growth factor 1 receptor (IGF-1R) signaling in cardiomyocytes is implicated in physiological hypertrophy and myocardial aging. Although fibroblasts account for a small amount of the heart, they are activated when the heart is damaged to promote cardiac remodeling. However, the role of IGF-1R signaling in cardiac fibroblasts is still unknown. In this study, we investigated the roles of IGF-1 signaling during agonist-induced cardiac fibrosis and evaluated the molecular mechanisms in cultured cardiac fibroblasts. Using an experimental model of cardiac fibrosis with angiotensin II/phenylephrine (AngII/PE) infusion, we found severe interstitial fibrosis in the AngII/PE infused myofibroblast-specific IGF-1R knockout mice compared to the wild-type mice. In contrast, low-dose IGF-1 infusion markedly attenuated AngII-induced cardiac fibrosis by inhibiting fibroblast proliferation and differentiation. Mechanistically, we demonstrated that IGF-1-attenuated AngII-induced cardiac fibrosis through the Akt pathway and through suppression of rho-associated coiled-coil containing kinases (ROCK)2-mediated α-smooth muscle actin (αSMA) expression. Our study highlights a novel function of the IGF-1/IGF-1R signaling in agonist-induced cardiac fibrosis. We propose that low-dose IGF-1 may be an efficacious therapeutic avenue against cardiac fibrosis.

The biological regulatory activities of Flammulina velutipes polysaccharide in mice intestinal microbiota, immune repertoire and heart transcriptome

The effects of a novel Flammulina velutipes polysaccharide (FVP) on intestinal microbiota, immune repertoire and heart transcriptome were investigated in this study. The results showed that FVP treatment could effectively regulate the abundance of colonic microbiota. And FVP exhibited obvious immunoregulatory effect by influencing V gene and J gene fragments usage on TCRα chain. The usage frequency of TRBV1, TRBJ1-6 and TRBJ1-5 were significantly altered, and 41 V-J pairs were identified with obvious difference after FVP treatment. Furthermore, the mRNA of mice heart was analyzed by transcriptome assay. Total 525 genes and 1587 mRNA were significantly changed after FVP treatment. KEGG annotation indicated that the up-regulated mRNA was enriched in 17 pathways including adherens junction, mTOR signaling pathway, insulin signaling pathway, mitophagy, tight junction, PPAR signaling pathway and TNF signaling pathway, etc. Meanwhile, the down-regulated mRNA was gathered in AMPK signaling pathway, metabolism of xenobiotics by cytochrome P450, apelin signaling pathway, PPAR signaling pathway, PI3K-Akt signaling pathway, insulin signaling pathway, cardiac muscle contraction, adrenergic signaling in cardiomyocytes, Fc gamma R-mediated phagocytosis, etc. The great potential exhibited by FVP could make it an ideal candidate as complementary medicine or functional food for promotion of health.

Toxocara canis Infection Alters lncRNA and mRNA Expression Profiles of Dog Bone Marrow

Bone marrow is the main hematopoietic organ that produces red blood cells, granulocytes, monocyte/macrophages, megakaryocytes, lymphocytes, and myeloid dendritic cells. Many of these cells play roles in the pathogenesis of Toxocara canis infection, and understanding how infection alters the dynamics of transcription regulation in bone marrow is therefore critical for deciphering the global changes in the dog transcriptional signatures during T. canis infection. In this study, long non-coding RNA (lncRNA) and messenger RNA (mRNA) expression profiles in the bone marrow of Beagle dogs infected with T. canis were determined at 12 h post-infection (hpi), 24 hpi, 96 hpi, and 36 days post-infection (dpi). RNA-sequencing and bioinformatics analysis identified 1,098, 984, 1,120, and 1,305 differentially expressed lncRNAs (DElncRNAs), and 196, 253, 223, and 328 differentially expressed mRNAs (DEmRNAs) at 12 h, 24 h, 96 h, and 36 days after infection, respectively. We also identified 29, 36, 38, and 68 DEmRNAs potentially cis-regulated by 44, 44, 51, and 80 DElncRNAs at 12 hpi, 24 hpi, 96 hpi, and 36 dpi, respectively. To validate the sequencing findings, qRT-PCR was performed on 10 randomly selected transcripts. Many altered genes were involved in the differentiation of bone marrow cells. GO of DElncRNAs and GO and KEGG pathway analyses of DEmRNAs revealed alterations in several signaling pathways, including pathways involved in energy metabolism, amino acid biosynthesis and metabolism, Wnt signaling pathway, Huntington's disease, HIF-1 signaling pathway, cGMP–PKG signaling pathway, dilated cardiomyopathy, and adrenergic signaling in cardiomyocytes. These findings revealed that bone marrow of T. canis-infected dogs exhibits distinct lncRNA and mRNA expression patterns compared to healthy control dogs. Our data provide novel insights into T. canis interaction with the definitive host and shed light on the significance of the non-coding portion of the dog genome in the pathogenesis of toxocariasis.

Fructose Metabolism and Cardiac Metabolic Stress.

Cardiovascular disease is one of the leading causes of mortality in diabetes. High fructose consumption has been linked with the development of diabetes and cardiovascular disease. Serum and cardiac tissue fructose levels are elevated in diabetic patients, and cardiac production of fructose via the intracellular polyol pathway is upregulated. The question of whether direct myocardial fructose exposure and upregulated fructose metabolism have potential to induce cardiac fructose toxicity in metabolic stress settings arises. Unlike tightly-regulated glucose metabolism, fructose bypasses the rate-limiting glycolytic enzyme, phosphofructokinase, and proceeds through glycolysis in an unregulated manner. In vivo rodent studies have shown that high dietary fructose induces cardiac metabolic stress and functional disturbance. In vitro, studies have demonstrated that cardiomyocytes cultured in high fructose exhibit lipid accumulation, inflammation, hypertrophy and low viability. Intracellular fructose mediates post-translational modification of proteins, and this activity provides an important mechanistic pathway for fructose-related cardiomyocyte signaling and functional effect. Additionally, fructose has been shown to provide a fuel source for the stressed myocardium. Elucidating the mechanisms of fructose toxicity in the heart may have important implications for understanding cardiac pathology in metabolic stress settings.