Cdon deficiency causes cardiac remodeling through hyperactivation of WNT/β-catenin signaling

Application Prospect of Induced Pluripotent Stem Cells in Organoids and Cell Therapy

Since its inception, induced pluripotent stem cell (iPSC) technology has been hailed as a powerful tool for comprehending disease etiology and advancing drug screening across various domains. While earlier iPSC-based disease modeling and drug assessment primarily operated at the cellular level, recent years have witnessed a significant shift towards organoid-based investigations. Organoids derived from iPSCs offer distinct advantages, particularly in enabling the observation of disease progression and drug metabolism in an in vivo-like environment, surpassing the capabilities of iPSC-derived cells. Furthermore, iPSC-based cell therapy has emerged as a focal point of clinical interest. In this review, we provide an extensive overview of non-integrative reprogramming methods that have evolved since the inception of iPSC technology. We also deliver a comprehensive examination of iPSC-derived organoids, spanning the realms of the nervous system, cardiovascular system, and oncology, as well as systematically elucidate recent advancements in iPSC-related cell therapies.

XAV939 Improves the Prognosis of Myocardial Infarction by Blocking the Wnt/β-Catenin Signalling Pathway

Myocardial infarction (MI) is closely related to the Wnt signalling pathway, but the role of XAV939 (a Wnt/β-catenin signalling pathway blocker) in MI has not been elucidated. The purpose of this study was to explore the role of XAV939 in mouse hearts and to provide a new and feasible treatment for improving the prognosis of MI. C57BL/6 (male, 8 weeks old, 20-25 g) mice were selected for our study. The MI model was made by ligating the left anterior descending coronary artery. On day 28 after the operation, cardiac function was examined by echocardiography. Infarct size, fibrosis, and angiogenesis were individually measured by TTC assays, Masson's trichrome staining, and CD31 analysis, respectively. Apoptosis was examined by TdT-mediated dUTP nick-end labelling (TUNEL) staining. The expression of Wnt, β-catenin, caspase 3, Bax, and Bcl-2 was determined by western blotting. XAV939 successfully blocked Wnt/β-catenin signalling pathway activation in cardiomyocytes after MI by promoting the degradation of β-catenin. XAV939 suppressed fibrosis and apoptosis, promoted angiogenesis, reduced myocardial infarct size and improved cardiac function after MI. XAV939 can reduce myocardial infarct size and improve cardiac function by blocking the Wnt/β-catenin signalling pathway, which may provide a new strategy for improving the prognosis of MI.

Increased GIRK channel activity prevents arrhythmia in mice with heart failure by enhancing ventricular repolarization

Ventricular arrhythmia causing sudden cardiac death is the leading mode of death in patients with heart failure. Yet, the mechanisms that prevent ventricular arrhythmias in heart failure are not well characterized. Using a mouse model of heart failure created by transverse aorta constriction, we show that GIRK channel, an important regulator of cardiac action potentials, is constitutively active in failing ventricles in contrast to normal cells. Evidence is presented indicating that the tonic activation of M2 muscarinic acetylcholine receptors by endogenously released acetylcholine contributes to the constitutive GIRK activity. This constitutive GIRK activity prevents the action potential prolongation in heart failure ventricles. Consistently, GIRK channel blockade with tertiapin-Q induces QT interval prolongation and increases the incidence of arrhythmia in heart failure, but not in control mice. These results suggest that constitutive GIRK channels comprise a key mechanism to protect against arrhythmia by providing repolarizing currents in heart failure ventricles.

Linggui Zhugan decoction delays ventricular remodeling in rats with chronic heart failure after myocardial infarction through the Wnt/β-catenin signaling pathway

CONTEXT

Traditional Chinese medicine plays an important role in the prevention and treatment of heart failure (HF). Linggui Zhugan decoction has been approved for clinical treatment of chronic HF. However, the mechanism is still unclear.

OBJECTIVE

The effect of Linggui Zhugan decoction on the Wnt/β-catenin signaling pathway in rat myocardium was studied to investigate the mechanism by Linggui Zhugan decoction effects ventricular remodeling in rats with heart failure after myocardial infarction.

METHOD

A rat model of HF after myocardial infarction was prepared by ligating the left anterior descending coronary artery. After 6 weeks of intervention with Linggui Zhugan decoction, the effect of Linggui Zhugan decoction on the cardiac function of chronic HF model rats was observed. Myocardial infarct size was measured by triphenyl tetrazolium chloride (TTC) staining. Enzyme linked immunosorbent assays (ELISAs) were used to measure NT-proBNP and sST-2 concentrations in rat serum. Hematoxylin and eosin (H&E) staining, and Masson's trichrome staining were used to observe the morphology of myocardial tissue; immunohistochemistry was used to detect the protein expression of type I collagen and type III collagen in myocardial tissue; and mRNA expression levels of Wnt3a, GSK-3β, β-catenin, and c-Myc in the infarct marginal zone were detected using PCR. Protein expression of Wnt3a, p-GSK-3β, GSK-3β, and β-catenin in the infarct marginal zone was detected using western blot.

RESULTS

Compared with the control, Linggui Zhugan decoction reduced the levels of serum ST-2 and NT-proBNP, improved cardiac function, and reduced the deposition of collagen fiber. In addition, Linggui Zhugan decoction inhibited the expression of Wnt3a, p-GSK-3β, and β-catenin in cardiomyocytes.

CONCLUSION

Linggui Zhugan decoction inhibits the expression of several key proteins in the Wnt/β-catenin signaling pathway, delays cardiomyocyte hypertrophy and fibrosis, and improves cardiac function.

Mutations in cdon and boc affect trunk neural crest cell migration and slow-twitch muscle development in zebrafish

The transmembrane proteins cdon and boc are implicated in regulating hedgehog signaling during vertebrate development. Recent work showing roles for these genes in axon guidance and neural crest cell migration suggest that cdon and boc may play additional functions in regulating directed cell movements. We use newly generated and existing mutants to investigate a role for cdon and boc in zebrafish neural crest cell migration. We find that single mutant embryos exhibit normal neural crest phenotypes, but that neural crest migration is strikingly disrupted in double cdon;boc mutant embryos. We further show that this migration phenotype is associated with defects in the differentiation of slow-twitch muscle cells, and the loss of a Col1a1a-containing extracellular matrix, suggesting that neural crest defects may be a secondary consequence to defects in mesoderm development. Combined, our data add to a growing literature showing that cdon and boc act synergistically to promote hedgehog signaling during vertebrate development, and suggest that the zebrafish can be used to study the function of hedgehog receptor paralogs.

Cdon suppresses vascular smooth muscle calcification via repression of the Wnt/Runx2 Axis

Osteogenic transdifferentiation of vascular smooth muscle cells (VSMCs) is a risk factor associated with vascular diseases. Wnt signaling is one of the major mechanisms implicated in the osteogenic conversion of VSMCs. Since Cdon has a negative effect on Wnt signaling in distinct cellular processes, we sought to investigate the role of Cdon in vascular calcification. The expression of Cdon was significantly downregulated in VSMCs of the aortas of patients with atherosclerosis and aortic stenosis. Consistently, calcification models, including vitamin D3 (VD3)-injected mice and VSMCs cultured with calcifying media, exhibited reduced Cdon expression. Cdon ablation mice (cKO) exhibited exacerbated aortic stiffness and calcification in response to VD3 compared to the controls. Cdon depletion induced the osteogenic conversion of VSMCs accompanied by cellular senescence. The Cdon-deficient aortas showed a significant alteration in gene expression related to cell proliferation and differentiation together with Wnt signaling regulators. Consistently, Cdon depletion or overexpression in VSMCs elevated or attenuated Wnt-reporter activities, respectively. The deletion mutant of the second immunoglobulin domain (Ig2) in the Cdon ectodomain failed to suppress Wnt signaling and osteogenic conversion of VSMCs. Furthermore, treatment with purified recombinant proteins of the entire ectodomain or Ig2 domain of Cdon displayed suppressive effects on Wnt signaling and VSMC calcification. Our results demonstrate a protective role of Cdon in VSMC calcification by suppressing Wnt signaling. The Ig2 domain of Cdon has the potential as a therapeutic tool to prevent vascular calcification.

The role of β-catenin in cardiac diseases

The Wnt/β-catenin signaling pathway is a classical Wnt pathway that regulates the stability and nuclear localization of β-catenin and plays an important role in adult heart development and cardiac tissue homeostasis. In recent years, an increasing number of researchers have implicated the dysregulation of this signaling pathway in a variety of cardiac diseases, such as myocardial infarction, arrhythmias, arrhythmogenic cardiomyopathy, diabetic cardiomyopathies, and myocardial hypertrophy. The morbidity and mortality of cardiac diseases are increasing, which brings great challenges to clinical treatment and seriously affects patient health. Thus, understanding the biological roles of the Wnt/β-catenin pathway in these diseases may be essential for cardiac disease treatment and diagnosis to improve patient quality of life. In this review, we summarize current research on the roles of β-catenin in human cardiac diseases and potential inhibitors of Wnt/β-catenin, which may provide new strategies for cardiac disease therapies.

Diabetes-induced chronic heart failure is due to defects in calcium transporting and regulatory contractile proteins: cellular and molecular evidence

Heart failure (HF) is a major deteriorating disease of the myocardium due to weak myocardial muscles. As such, the heart is unable to pump blood efficiently around the body to meet its constant demand. HF is a major global health problem with more than 7 million deaths annually worldwide, with some patients dying suddenly due to sudden cardiac death (SCD). There are several risk factors which are associated with HF and SCD which can negatively affect the heart synergistically. One major risk factor is diabetes mellitus (DM) which can cause an elevation in blood glucose level or hyperglycaemia (HG) which, in turn, has an insulting effect on the myocardium. This review attempted to explain the subcellular, cellular and molecular mechanisms and to a lesser extent, the genetic factors associated with the development of diabetes- induced cardiomyopathy due to the HG which can subsequently lead to chronic heart failure (CHF) and SCD. The study first explained the structure and function of the myocardium and then focussed mainly on the excitation-contraction coupling (ECC) processes highlighting the defects of calcium transporting (SERCA, NCX, RyR and connexin) and contractile regulatory (myosin, actin, titin and troponin) proteins. The study also highlighted new therapies and those under development, as well as preventative strategies to either treat or prevent diabetic cardiomyopathy (DCM). It is postulated that prevention is better than cure.

PRELP promotes myocardial fibrosis and ventricular remodelling after acute myocardial infarction by the wnt/β-catenin signalling pathway

OBJECTIVES

Proline/arginine-rich end leucine-rich repeat protein (PRELP) has been reported to contribute to the remodelling of cardiovascular tissues in the ischaemia-reperfusion injury model. However, research is lacking on the role of PRELP in myocardial fibrosis and ventricular remodelling, and the mechanism through which PRELP brings about these changes is not clear. This study aimed to evaluate the role of PRELP in ventricular remodelling and myocardial fibrosis following acute myocardial infarction (AMI) and to explore the underlying mechanism.

METHODS

In this study, we established AMI mouse and cellculture models in an oxygen-glucose deprivation environment.

RESULTS

We found that over-expression of PRELP increased the infarct size and interstitial fibrotic area. Expression of the wnt/β-catenin pathway molecules, which are downstream of PRELP, increased more in the PRELP over-expression group than in the AMI group.

CONCLUSIONS

Our results showed that PRELP, through the wnt/β-catenin signalling pathway, led to myocardial fibrosis and ventricular remodelling following AMI.

PRMT1 suppresses doxorubicin-induced cardiotoxicity by inhibiting endoplasmic reticulum stress

Doxorubicin (Dox) is a widely used anti-cancer drug that has a significant limitation, which is cardiotoxicity. Its cardiotoxic side effect is dose dependent and occurs through any age. Dox has been known to exert its toxic effect through oxidative stress, but an emerging mechanism is endoplasmic reticulum (ER) stress that activates proapoptotic pathway involving PERK/ATF4/CHOP axis. These stresses lead to dysfunction of myocardium associated with cell death. Although accumulating evidence support their involvement to Dox-induced cardiotoxicity, the mechanism is not well elucidated. Protein arginine methyltransferases 1 (PRMT1) has been known to play a role in cardiomyocyte cell survival through modulation of ER response. In this study, we demonstrate an important role of PRMT1 in Dox-induced cardiotoxicity via ER stress. Depletion of PRMT1 in H9c2 cardiomyocytes enhanced Dox-stimulated cell death, and increased reactive oxygen species (ROS) production and DNA damage by enhancing the levels of proapoptotic cleaved Caspase-3 and γH2AX in response to Dox. Consistently, overexpression of PRMT1 attenuated the apoptotic effect of Dox. In addition, the acute treatment of Dox induced a substantial increase in PRMT1 activity and the translocation of PRMT1 to ER. Overexpression of PRMT1 in cardiomyocyte diminished Dox-induced ER stress, and ATF4 methylation by PRMT1 was involved in the suppression of ER stress. Taken together, our data suggest that PRMT1 is a novel target molecule for protection from Dox-induced cardiotoxicity.

Hedgehog Morphogens Act as Growth Factors Critical to Pre- and Postnatal Cardiac Development and Maturation: How Primary Cilia Mediate Their Signal Transduction

Primary cilia are crucial for normal cardiac organogenesis via the formation of cyto-architectural, anatomical, and physiological boundaries in the developing heart and outflow tract. These tiny, plasma membrane-bound organelles function in a sensory-integrative capacity, interpreting both the intra- and extra-cellular environments and directing changes in gene expression responses to promote, prevent, and modify cellular proliferation and differentiation. One distinct feature of this organelle is its involvement in the propagation of a variety of signaling cascades, most notably, the Hedgehog cascade. Three ligands, Sonic, Indian, and Desert hedgehog, function as growth factors that are most commonly dependent on the presence of intact primary cilia, where the Hedgehog receptors Patched-1 and Smoothened localize directly within or at the base of the ciliary axoneme. Hedgehog signaling functions to mediate many cell behaviors that are critical for normal embryonic tissue/organ development. However, inappropriate activation and/or upregulation of Hedgehog signaling in postnatal and adult tissue is known to initiate oncogenesis, as well as the pathogenesis of other diseases. The focus of this review is to provide an overview describing the role of Hedgehog signaling and its dependence upon the primary cilium in the cell types that are most essential for mammalian heart development. We outline the breadth of developmental defects and the consequential pathologies resulting from inappropriate changes to Hedgehog signaling, as it pertains to congenital heart disease and general cardiac pathophysiology.

Inhibition of PRMT6 reduces neomycin-induced inner ear hair cell injury through the restraint of FoxG1 arginine methylation

OBJECTIVE

Hair cells in the inner ear have been demonstrated to be sensitive to the ototoxicity from some beneficial pharmaceutical drugs. This study aimed to explore the role of protein arginine methyltransferase 6 (PRMT6) in the process of neomycin-induced hearing loss and the underlying mechanism.

METHODS

The neomycin-induced hearing loss mouse model and hair cell injury in vitro model were established. We took advantage of the HEI-OC1 cell line to evaluate PRMT6 expression in neomycin-induced hair cells, and the effect of PRMT6 on mitochondrial function and FoxG1 arginine methylation. Apoptotic cells were assessed and apoptotic marker cleaved caspase-3 level was detected. Reactive oxygen species (ROS) level and mitochondrial membrane potential (MMP) were subsequently measured.

RESULT

The result showed that PRMT6 was significantly upregulated in neomycin-induced HEI-OC-1 cells, and PRMT6 silencing prevented MMP loss, reduced ROS production, as well as decreased cell apoptosis under neomycin treatment. Further results showed that FoxG1 was downregulated in neomycin-induced HEI-OC-1 cells, and PRMT6 promoted the FoxG1-mediated luciferase activity, while PRMT6 silencing reversed this effect. Mechanistic experiments revealed that PRMT6 silencing reduced the arginine methylation level of FoxG1 protein. In vivo, neomycin-induced upregulation of hearing thresholds and increased cell apoptosis, whereas PRMT6 inhibitor partly reversed these effects.

CONCLUSION

Our findings suggested that inhibition of PRMT6 reduced neomycin-induced inner ear hair cell injury through the restraint of FoxG1 arginine methylation.

PRMT7 ablation in cardiomyocytes causes cardiac hypertrophy and fibrosis through β-catenin dysregulation

Angiotensin II (AngII) has potent cardiac hypertrophic effects mediated through activation of hypertrophic signaling like Wnt/β-Catenin signaling. In the current study, we examined the role of protein arginine methyltransferase 7 (PRMT7) in cardiac function. PRMT7 was greatly decreased in hypertrophic hearts chronically infused with AngII and cardiomyocytes treated with AngII. PRMT7 depletion in rat cardiomyocytes resulted in hypertrophic responses. Consistently, mice lacking PRMT7 exhibited the cardiac hypertrophy and fibrosis. PRMT7 overexpression abrogated the cellular hypertrophy elicited by AngII, while PRMT7 depletion exacerbated the hypertrophic response caused by AngII. Similar with AngII treatment, the cardiac transcriptome analysis of PRMT7-deficient hearts revealed the alteration in gene expression profile related to Wnt signaling pathway. Inhibition of PRMT7 by gene deletion or an inhibitor treatment enhanced the activity of β-catenin. PRMT7 deficiency decreases symmetric dimethylation of β-catenin. Mechanistic studies reveal that methylation of arginine residue 93 in β-catenin decreases the activity of β-catenin. Taken together, our data suggest that PRMT7 is important for normal cardiac function through suppression of β-catenin activity.

ERGIC2 and ERGIC3 regulate the ER-to-Golgi transport of gap junction proteins in metazoans

The extremely dynamic life cycle of gap junction connections requires highly efficient intracellular trafficking system especially designed for gap junction proteins, but the underlying mechanisms are largely unknown. Here, we identified that the COPII-associated proteins ERGIC2 (ER-Golgi intermediate compartment) and ERGIC3 are specifically required for the efficient intracellular transport of gap junction proteins in both C. elegans and mice. In the absence of Ergic2 or Ergic3, gap junction proteins accumulate in the ER and Golgi apparatus and the size of endogenous gap junction plaques is reduced. Knocking out the Ergic2 or Ergic3 in mice results in heart enlargement and cardiac malfunction accompanied by reduced number and size of connexin 43 (Cx43) gap junctions. Invertebrates' gap junction protein innexins share no sequence similarity with vertebrates' connexins. However, ERGIC2 and ERGIC3 could bind to gap junction proteins in both worms and mice. Characterization of the highly specialized roles of ERGIC2 and ERGIC3 in metazoans reveals how the early secretory pathway could be adapted to facilitate the efficient transport for gap junction proteins in vivo. This article is protected by copyright. All rights reserved.

Decrease of Pdzrn3 is required for heart maturation and protects against heart failure

Heart failure is the final common stage of most cardiopathies. Cardiomyocytes (CM) connect with others via their extremities by intercalated disk protein complexes. This planar and directional organization of myocytes is crucial for mechanical coupling and anisotropic conduction of the electric signal in the heart. One of the hallmarks of heart failure is alterations in the contact sites between CM. Yet no factor on its own is known to coordinate CM polarized organization. We have previously shown that PDZRN3, an ubiquitine ligase E3 expressed in various tissues including the heart, mediates a branch of the Planar cell polarity (PCP) signaling involved in tissue patterning, instructing cell polarity and cell polar organization within a tissue. PDZRN3 is expressed in the embryonic mouse heart then its expression dropped significantly postnatally corresponding with heart maturation and CM polarized elongation. A moderate CM overexpression of Pdzrn3 (Pdzrn3 OE) during the first week of life, induced a severe eccentric hypertrophic phenotype with heart failure. In models of pressure-overload stress heart failure, CM-specific Pdzrn3 knockout showed complete protection against degradation of heart function. We reported that Pdzrn3 signaling induced PKC ζ expression, c-Jun nuclear translocation and a reduced nuclear ß catenin level, consistent markers of the planar non-canonical Wnt signaling in CM. We then show that subcellular localization (intercalated disk) of junction proteins as Cx43, ZO1 and Desmoglein 2 was altered in Pdzrn3 OE mice, which provides a molecular explanation for impaired CM polarization in these mice. Our results reveal a novel signaling pathway that controls a genetic program essential for heart maturation and maintenance of overall geometry, as well as the contractile function of CM, and implicates PDZRN3 as a potential therapeutic target for the prevention of human heart failure.

Transcriptome sequencing reveals a lncRNA-mRNA interaction network in extramammary Paget's disease

Background

Extramammary Paget’s disease (EMPD) is a rare malignant intraepidermal adenocarcinoma that is poorly understood. Regulatory long noncoding RNAs (lncRNAs) are characterized in many species and shown to be involved in processes such as development and pathologies, revealing a new layer of regulation in different diseases, especially in cancer studies. In the present study, we used high-throughput sequencing to reveal the lncRNA–mRNA interaction network in extramammary Paget’s disease.

Methods

High-throughput sequencing was used to identify differentially expressed lncRNA and mRNA profiles between EMPD patients and healthy controls. Then, a series of bioinformatics analyses were conducted to construct the lncRNA–mRNA interaction network, which was finally confirmed in vitro.

Results

Six pairs of EMPD tumor and normal skin samples were collected and sequenced to identify the differentially expressed lncRNA and mRNA profiles between EMPD and healthy controls. A total of 997 differentially expressed mRNAs and 785 differentially expressed lncRNAs were identified. The GO and KEGG analyses show that epidermal development and cell adhesion play important roles in EMPD. The results of the lncRNA–mRNA interaction network analysis suggested that NEAT1, PGAP1, FKBP5 and CDON were the pivotal nodes of the network and that lncRNA NEAT1 might regulate mRNA PGAP1, FKBP5 and CDON. The results of the quantitative real-time RT–PCR performed in ten other patients for NEAT1, PGAP1, FKBP5 and CDON were consistent with those of the sequencing analysis. Moreover, an in vitro experiment confirmed the interactions between NEAT1 and PGAP1, FKBP5 and CDON in human immortalized keratinocytes.

Conclusion

These findings suggest that the lncRNA–mRNA interaction network based on four pivotal nodes, NEAT1, PGAP1 FKBP5 and CDON, may play an important role in EMPD, which will contribute to a deeper understanding of the pathogenesis of EMPD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01135-2.

Inducible Prmt1 ablation in adult vascular smooth muscle leads to contractile dysfunction and aortic dissection

Vascular smooth muscle cells (VSMCs) have remarkable plasticity in response to diverse environmental cues. Although these cells are versatile, chronic stress can trigger VSMC dysfunction, which ultimately leads to vascular diseases such as aortic aneurysm and atherosclerosis. Protein arginine methyltransferase 1 (Prmt1) is a major enzyme catalyzing asymmetric arginine dimethylation of proteins that are sources of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase. Although a potential role of Prmt1 in vascular pathogenesis has been proposed, its role in vascular function has yet to be clarified. Here, we investigated the role and underlying mechanism of Prmt1 in vascular smooth muscle contractility and function. The expression of PRMT1 and contractile-related genes was significantly decreased in the aortas of elderly humans and patients with aortic aneurysms. Mice with VSMC-specific Prmt1 ablation (smKO) exhibited partial lethality, low blood pressure and aortic dilation. The Prmt1-ablated aortas showed aortic dissection with elastic fiber degeneration and cell death. Ex vivo and in vitro analyses indicated that Prmt1 ablation significantly decreased the contractility of the aorta and traction forces of VSMCs. Prmt1 ablation downregulated the expression of contractile genes such as myocardin while upregulating the expression of synthetic genes, thus causing the contractile to synthetic phenotypic switch of VSMCs. In addition, mechanistic studies demonstrated that Prmt1 directly regulates myocardin gene activation by modulating epigenetic histone modifications in the myocardin promoter region. Thus, our study demonstrates that VSMC Prmt1 is essential for vascular homeostasis and that its ablation causes aortic dilation/dissection through impaired myocardin expression.

The protein inputs of an ultra-predictive aging clock represent viable anti-aging drug targets

Machine learning models capable of predicting age given a set of inputs are referred to as aging clocks. We recently developed an aging clock that utilizes 491 plasma protein inputs, has an exceptional accuracy, and is capable of measuring biological age. Here, we demonstrate that this clock is extremely predictive (r = 0.95) when used to measure age in a novel plasma proteomic dataset derived from 370 human subjects aged 18-69 years. Over-representation analyses of the proteins that make up this clock in the Gene Ontology and Reactome databases predominantly implicated innate and adaptive immune system processes. Immunological drugs and various age-related diseases were enriched in the DrugBank and GLAD4U databases. By performing an extensive literature review, we find that at least 269 (54.8 %) of these inputs regulate lifespan and/or induce changes relevant to age-related disease when manipulated in an animal model. We also show that, in a large plasma proteomic dataset, the majority (57.2 %) of measurable clock proteins significantly change their expression level with human age. Different subsets of proteins were overlapped with distinct epigenetic, transcriptomic, and proteomic aging clocks. These findings indicate that the inputs of this age predictor likely represent a rich source of anti-aging drug targets.

Whole Genome Level Analysis of the Wnt and DIX Gene Families in Mice and Their Coordination Relationship in Regulating Cardiac Hypertrophy

The Wnt signaling pathway is an evolutionarily conserved signaling pathway that plays essential roles in embryonic development, organogenesis, and many other biological activities. Both Wnt proteins and DIX proteins are important components of Wnt signaling. Systematic studies of Wnt and DIX families at the genome-wide level may provide a comprehensive landscape to elucidate their functions and demonstrate their relationships, but they are currently lacking. In this report, we describe the correlations between mouse Wnt and DIX genes in family expansion, molecular evolution, and expression levels in cardiac hypertrophy at the genome-wide scale. We observed that both the Wnt and DIX families underwent more expansion than the overall average in the evolutionarily early stage. In addition, mirrortree analyses suggested that Wnt and DIX were co-evolved protein families. Collectively, these results would help to elucidate the evolutionary characters of Wnt and DIX families and demonstrate their correlations in mediating cardiac hypertrophy.

Plasma Proteomic Profiling in Hypertrophic Cardiomyopathy Patients before and after Surgical Myectomy Reveals Post-Procedural Reduction in Systemic Inflammation

Left Ventricular Outflow Tract (LVOT) obstruction occurs in approximately 70% of Hypertrophic Cardiomyopathy (HCM) patients and currently requires imaging or invasive testing for diagnosis, sometimes in conjunction with provocative physiological or pharmaceutical stimuli. To identify potential biomarkers of LVOT obstruction, we performed proteomics profiling of 1305 plasma proteins in 12 HCM patients with documented LVOT obstruction, referred for surgical myectomy. Plasma was collected at the surgical preoperative visit, approximately one month prior to surgery and then at the post-surgical visit, approximately 3 months later. Proteomic profiles were generated using the aptamer-based SOMAscan assay. Principal Component Analysis using the highest statistically significant proteins separated all preoperative samples from all postoperative samples. Further analysis revealed a set of 25 proteins that distinguished the preoperative and postoperative states with a paired t-test p-value of <0.01. Ingenuity Pathway analysis facilitated the generation of protein interaction networks and the elucidation of key upstream regulators of differentially expressed proteins, such as interferon-γ, TGF-β1, and TNF. Biological pathways affected by surgery included organ inflammation, migration, and motility of leukocytes, fibrosis, vasculogenesis, angiogenesis, acute coronary events, endothelial proliferation, eicosanoid metabolism, calcium flux, apoptosis, and morphology of the cardiovascular system. Our results indicate that surgical relief of dynamic outflow tract obstruction in HCM patients is associated with unique alterations in plasma proteomic profiles that likely reflect improvement in organ inflammation and physiological function.

Kelly M, M. Buchowski J, P. Zebala L, Luhmann S, C. Gupta M, A. Setton L. Verteporfin treatment controls morphology, phenotype, and global gene expression for cells of the human nucleus pulposus

Cells of the nucleus pulposus (NP) are essential contributors to extracellular matrix synthesis and function of the intervertebral disc. With age and degeneration, the NP becomes stiffer and more dehydrated, which is associated with a loss of phenotype and biosynthetic function for its resident NP cells. Also, with aging, the NP cell undergoes substantial morphological changes from a rounded shape with pronounced vacuoles in the neonate and juvenile, to one that is more flattened and spread with a loss of vacuoles. Here, we make use of the clinically relevant pharmacological treatment verteporfin (VP), previously identified as a disruptor of yes-associated protein-TEA domain family member-binding domain (TEAD) signaling, to promote morphological changes in adult human NP cells in order to study variations in gene expression related to differences in cell shape. Treatment of adult, degenerative human NP cells with VP caused a shift in morphology from a spread, fibroblastic-like shape to a rounded, clustered morphology with decreased transcriptional activity of TEAD and serum-response factor. These changes were accompanied by an increased expression of vacuoles, NP-specific gene markers, and biosynthetic activity. The contemporaneous observation of VP-induced changes in cell shape and prominent, time-dependent changes within the transcriptome of NP cells occurred over all timepoints in culture. Enriched gene sets with the transition to VP-induced cell rounding suggest a major role for cell adhesion, cytoskeletal remodeling, vacuolar lumen, and MAPK activity in the NP phenotypic and functional response to changes in cell shape.

Exome sequencing in patients with microphthalmia, anophthalmia, and coloboma (MAC) from a consanguineous population

Next-generation sequencing strategies have resulted in mutation detection rates of 21% to 61% in small cohorts of patients with microphthalmia, anophthalmia and coloboma (MAC), but despite progress in identifying novel causative genes, many patients remain without a genetic diagnosis. We studied a cohort of 19 patients with MAC who were ascertained from a population with high rates of consanguinity. Using single nucleotide polymorphism (SNP) arrays and whole exome sequencing (WES), we identified one pathogenic variant in TENM3 in a patient with cataracts in addition to MAC. We also detected novel variants of unknown significance in genes that have previously been associated with MAC, including KIF26B, MICU1 and CDON, and identified variants in candidate genes for MAC from the Wnt signaling pathway, comprising LRP6, WNT2B and IQGAP1, but our findings do not prove causality. Plausible variants were not found for many of the cases, indicating that our current understanding of the pathogenesis of MAC, a highly heterogeneous group of ocular defects, remains incomplete.

Deletion of Microfibrillar-Associated Protein 4 Attenuates Left Ventricular Remodeling and Dysfunction in Heart Failure

Background

Cardiac remodeling predisposes individuals to heart failure if the burden is not solved, and heart failure is a growing cause of morbidity and mortality worldwide. The cardiac extracellular matrix not only provides structural support, but also is a core aspect of the myocardial response to various biomechanical stresses and heart failure. MFAP4 (microfibrillar‐associated protein 4) is an integrin ligand located in the extracellular matrix, whose biological functions in the heart remain poorly understood. In the current study we aimed to test the role of MFAP4 in cardiac remodeling.

Methods and Results

MFAP4‐deficient (MFAP4^−/−) and wild‐type mice were subjected to aortic banding surgery and isoproterenol to establish models of cardiac remodeling. We also evaluated the functional effects of MFAP4 on cardiac hypertrophy, fibrosis, and cardiac electrical remodeling. The expression of MFAP4 was increased in the animal cardiac remodeling models induced by pressure overload and isoproterenol. After challenge of 8 weeks of aortic banding or 2 weeks of intraperitoneal isoproterenol, MFAP4^−/− mice exhibited lower levels of cardiac fibrosis and fewer ventricular arrhythmias than wild‐type mice. However, there was no significant effect on cardiomyocyte hypertrophy. In addition, there was no significant difference in cardiac fibrosis severity, hypertrophy, or ventricular arrhythmia incidence between wild‐type‐sham and knockout‐sham mice.

Conclusions

These findings are the first to demonstrate that MFAP4 deficiency inhibits cardiac fibrosis and ventricular arrhythmias after challenge with 8 weeks of aortic banding or 2 weeks of intraperitoneal isoproterenol but does not significantly affect the hypertrophy response. In addition, MFAP4 deficiency had no significant effect on cardiac fibrosis, hypertrophy, or ventricular arrhythmia in the sham group in this study.

Cardiac β-adrenergic receptor activation mediates distinct and cell type-dependent changes in the expression and distribution of connexin 43

Activation of the sympatho-β-adrenergic receptors (β-ARs) system is a hallmark of heart failure, leading to fibrosis and arrhythmias. Connexin 43 (Cx43) is the most abundant gap junctional protein in the myocardium. Current knowledge is limited regarding Cx43 remodelling in diverse cell types in the diseased myocardium and the underlying mechanism. We studied cell type-dependent changes in Cx43 remodelling due to β-AR overactivation and molecular mechanisms involved. Mouse models of isoproterenol stimulation or transgenic cardiomyocyte overexpression of β₂ -AR were used, which exhibited cardiac fibrosis and up-regulated total Cx43 abundance. In both models, whereas Cx43 expression in cardiomyocytes was reduced and more laterally distributed, fibroblasts exhibited elevated Cx43 expression and enhanced gap junction communication. Mechanistically, activation of β₂ -AR in fibroblasts in vitro elevated Cx43 expression, which was abolished by the β₂ -antagonist ICI-118551 or protein kinase A inhibitor H-89, but simulated by the adenylyl cyclase activator forskolin. Our in vitro and in vivo data showed that β-AR activation-induced production of IL-18 sequentially stimulated Cx43 expression in fibroblasts in a paracrine fashion. In summary, our findings demonstrate a pivotal role of β-AR in mediating distinct and cell type-dependent changes in the expression and distribution of Cx43, leading to pathological gap junction remodelling in the myocardium.

KLF15-Wnt-Dependent Cardiac Reprogramming Up-Regulates SHISA3 in the Mammalian Heart

BACKGROUND

The combination of cardiomyocyte (CM) and vascular cell (VC) fetal reprogramming upon stress culminates in end-stage heart failure (HF) by mechanisms that are not fully understood. Previous studies suggest KLF15 as a key regulator of CM hypertrophy.

OBJECTIVES

This study aimed to characterize the impact of KLF15-dependent cardiac transcriptional networks leading to HF progression, amenable to therapeutic intervention in the adult heart.

METHODS

Transcriptomic bioinformatics, phenotyping of Klf15 knockout mice, Wnt-signaling-modulated hearts, and pressure overload and myocardial ischemia models were applied. Human KLF15 knockout embryonic stem cells and engineered human myocardium, and human samples were used to validate the relevance of the identified mechanisms.

RESULTS

The authors identified a sequential, postnatal transcriptional repression mediated by KLF15 of pathways implicated in pathological tissue remodeling, including distinct Wnt-pathways that control CM fetal reprogramming and VC remodeling. The authors further uncovered a vascular program induced by a cellular crosstalk initiated by CM, characterized by a reduction of KLF15 and a concomitant activation of Wnt-dependent transcriptional signaling. Within this program, a so-far uncharacterized cardiac player, SHISA3, primarily expressed in VCs in fetal hearts and pathological remodeling was identified. Importantly, the KLF15 and Wnt codependent SHISA3 regulation was demonstrated to be conserved in mouse and human models.

CONCLUSIONS

The authors unraveled a network interplay defined by KLF15-Wnt dynamics controlling CM and VC homeostasis in the postnatal heart and demonstrated its potential as a cardiac-specific therapeutic target in HF. Within this network, they identified SHISA3 as a novel, evolutionarily conserved VC marker involved in pathological remodeling in HF.

BST204, a Rg3 and Rh2 Enriched Ginseng Extract, Upregulates Myotube Formation and Mitochondrial Function in TNF-α-Induced Atrophic Myotubes

The loss of skeletal muscle mass and function is a serious consequence of chronic diseases and aging. BST204 is a purified ginseng (the root of Panax ginseng) extract that has been processed using ginsenoside-β-glucosidase and acid hydrolysis to enrich ginsenosides Rg3 and Rh2 from the crude ginseng. BST204 has a broad range of health benefits, but its effects and mechanism on muscle atrophy are currently unknown. In this study, we have examined the effects and underlying mechanisms of BST204 on myotube formation and myotube atrophy induced by tumor necrosis factor-α (TNF-α). BST204 promotes myogenic differentiation and multinucleated myotube formation through Akt activation. BST204 prevents myotube atrophy induced by TNF-α through the activation of Akt/mTOR signaling and down-regulation of muscle-specific ubiquitin ligases, MuRF1, and Atrogin-1. Furthermore, BST204 treatment in atrophic myotubes suppresses mitochondrial reactive oxygen species (ROS) production and regulates mitochondrial transcription factors such as NRF1 and Tfam, through enhancing the activity and expression of peroxisome proliferator-activated receptor-γ coactivator1α (PGC1α). Collectively, our findings indicate that BST204 improves myotube formation and PGC1α-mediated mitochondrial function, suggesting that BST204 is a potential therapeutic or neutraceutical remedy to intervene muscle weakness and atrophy.

Multiple Roles of sFRP2 in Cardiac Development and Cardiovascular Disease

The Wnt signaling pathway plays important roles in organ development and disease processes. Secreted frizzled-related protein 2 (sFRP2), a vital molecule of Wnt signaling, can regulate cardiac development and cardiovascular disease. Recent studies have suggested that sFRP2 is not only an antagonist of the canonical Wnt signaling pathway, but also has a more complex relationship in myocardial fibrosis, angiogenesis, cardiac hypertrophy and cardiac regeneration. Here, we review the role of sFRP2 and Wnt signaling in cardiac development and cardiovascular disease.

PRMT1 suppresses ATF4-mediated endoplasmic reticulum response in cardiomyocytes

Endoplasmic reticulum (ER) stress signaling plays a critical role in the control of cell survival or death. Persistent ER stress activates proapoptotic pathway involving the ATF4/CHOP axis. Although accumulating evidences support its important contribution to cardiovascular diseases, but its mechanism is not well characterized. Here, we demonstrate a critical role for PRMT1 in the control of ER stress in cardiomyocytes. The inhibition of PRMT1 augments tunicamycin (TN)-triggered ER stress response in cardiomyocytes while PRMT1 overexpression attenuates it. Consistently, PRMT1 null hearts show exacerbated ER stress and cell death in response to TN treatment. Interestingly, ATF4 depletion attenuates the ER stress response induced by PRMT1 inhibition. The methylation-deficient mutant of ATF4 with the switch of arginine 239 to lysine exacerbates ER stress accompanied by enhanced levels of proapoptotic cleaved Caspase3 and phosphorylated-γH2AX in response to TN. The mechanistic study shows that PRMT1 modulates the protein stability of ATF4 through methylation. Taken together, our data suggest that ATF4 methylation on arginine 239 by PRMT1 is a novel regulatory mechanism for protection of cardiomyocytes from ER stress-induced cell death.

The deacetylase sirtuin 6 protects against kidney fibrosis by epigenetically blocking β-catenin target gene expression

Fibrosis is a common pathologic pathway of progressive kidney disease involving complex signaling networks. The deacetylase sirtuin 6 (sirt6) was recently implicated in kidney injury. However, it remains elusive whether and how sirt6 contributes to the regulation of kidney fibrosis. Here, we demonstrate that sirt6 protects against kidney interstitial fibrosis through epigenetic regulation of β-catenin signaling. Sirt6 is markedly upregulated during fibrogenesis following obstructed nephropathy and kidney ischemia-reperfusion injury. Pharmacological inhibition of sirt6 deacetylase activity aggravates kidney fibrosis in obstructed nephropathy. Consistently, knockdown of sirt6 in mouse kidney proximal tubular epithelial cells aggravates transforming growth factor-β-induced fibrosis in vitro. Mechanistically, sirt6 deficiency results in augmented expression of the downstream target proteins of β-catenin signaling. We further show that sirt6 interacts with β-catenin during transforming growth factor-β treatment and binds to the promoters of β-catenin target genes, resulting in the deacetylation of histone H3K56 to prevent the transcription of fibrosis-related genes. Thus, our data reveal the anti-fibrotic function of sirt6 by epigenetically attenuating β-catenin target gene expression.

Activation of hedgehog signaling in mesenchymal stem cells induces cartilage and bone tumor formation via Wnt/β-Catenin

Indian Hedgehog (IHH) signaling, a key regulator of skeletal development, is highly activated in cartilage and bone tumors. Yet deletion of Ptch1, encoding an inhibitor of IHH receptor Smoothened (SMO), in chondrocyte or osteoblasts does not cause tumorigenesis. Here, we show that Ptch1 deletion in mice Prrx1⁺mesenchymal stem/stromal cells (MSCs) promotes MSC proliferation and osteogenic and chondrogenic differentiation but inhibits adipogenic differentiation. Moreover, Ptch1 deletion led to development of osteoarthritis-like phenotypes, exostoses, enchondroma, and osteosarcoma in Smo-Gli1/2-dependent manners. The cartilage and bone tumors are originated from Prrx1⁺ lineage cells and express low levels of osteoblast and chondrocyte markers, respectively. Mechanistically, Ptch1 deletion increases the expression of Wnt5a/6 and leads to enhanced β-Catenin activation. Inhibiting Wnt/β-Catenin pathway suppresses development of skeletal anomalies including enchondroma and osteosarcoma. These findings suggest that cartilage/bone tumors arise from their early progenitor cells and identify the Wnt/β-Catenin pathway as a pharmacological target for cartilage/bone neoplasms.

Bone and cartilage tumors are among the most common tumors in the skeleton, often affecting the limbs. Bone tumors, also called osteosarcomas, usually occur in growing children and teenagers, and they are often resistant to conventional chemo- and radio-therapies. Surgery is the only treatment option, but this can lead to long-lasting damage that impairs the quality of life of these patients. Thus, there is a need to find new drug targets for these diseases. Unfortunately, no good laboratory-based systems exist that mimic these human cancers, hindering research into these tumors.

One way to create a laboratory-based model for cartilage tumors and osteosarcomas is to reproduce the signaling that is present in the human tumors in a mouse. A signaling pathway called Hedgehog signaling is overactive in human cartilage and bone tumors. The activity of this pathway can be increased by deleting a gene called Ptch1; but mice do not form tumors when this gene is deleted in their mature cartilage and bone cells.

Now, Deng, Li et al. report that deleting Ptch1 in mesenchymal stem cells, early-stage cells that can give rise to cartilage and bone cells, generates a mouse model for osteosarcoma and cartilage tumors. The mice with these Ptch1 deficient cells developed tumors with overactive Hedgehog signaling in cartilage and bone. Deng, Li et al. also performed biochemical experiments to show that Hedgehog signaling turned on another signaling pathway called Wnt signaling. Treating the mice that had mesenchymal cells lacking Ptch1 with a drug that inhibits Wnt signaling reduced the growth of cartilage and bone tumors.

These data suggest that deleting Ptch1 in mouse mesenchymal stem cells can mimic human cartilage tumors and osteosarcomas. More experiments will be needed to explain how the Hedgehog and Wnt signaling pathways interact in these tumors. Finally, further studies will need to investigate if inhibiting Wnt signaling might become a useful therapy for human patients with osteosarcoma in the future.

Prmt7 promotes myoblast differentiation via methylation of p38MAPK on arginine residue 70

MyoD functions as a master regulator to induce muscle-specific gene expression and myogenic differentiation. Here, we demonstrate a positive role of Protein arginine methyltransferase 7 (Prmt7) in MyoD-mediated myoblast differentiation through p38MAPK activation. Prmt7 depletion in primary or C2C12 myoblasts impairs cell cycle withdrawal and myogenic differentiation. Furthermore, Prmt7 depletion decreases the MyoD-reporter activities and the MyoD-mediated myogenic conversion of fibroblasts. Together with MyoD, Prmt7 is recruited to the Myogenin promoter region and Prmt7 depletion attenuates the recruitment of MyoD and its coactivators. The mechanistic study reveals that Prmt7 methylates p38MAPKα at the arginine residue 70, thereby promoting its activation which in turn enhances MyoD activities. The arginine residue 70 to alanine mutation in p38MAPKα impedes MyoD/E47 heterodimerization and the recruitment of Prmt7, MyoD and Baf60c to the Myogenin promoter resulting in blunted Myogenin expression. In conclusion, Prmt7 promotes MyoD-mediated myoblast differentiation through methylation of p38MAPKα at arginine residue 70.

Transcriptomic profiling of neural stem cell differentiation on graphene substrates

Graphene exhibits excellent mechanical strength, electrical conductivity and good biocompatibility, which make it a suitable candidate as a neural interfacing material in regenerative medicine and tissue engineering. Graphene is reported to promote both of neural stem cells (NSCs) proliferation and differentiation. However, the transcriptomes of 2D graphene-regulated NSC differentiation have not yet been investigated. To identify candidate genes, on which graphene may affect, we used next-generation RNA sequencing to analyze the transcriptome of NSCs differentiated for 21 days on a graphene substrate. These NSCs displayed highly enriched and differentially expressed genes compared with traditional cell culture in vitro. Of these, we identified motor protein genes that might regulate NSC differentiation, including cytoplasmic dynein and axonemal dynein genes, Ccdc108, Dnah5, and Dnah11. Furthermore, we analyzed the cell signaling pathway genes that might regulate NSC differentiation, and we constructed a protein-protein interaction network for the genes that are differentially expressed in NSCs on graphene compared to commercial tissue culture polystyrene substrates. We have identified genes potentially regulating the differentiation and migration of NSCs on graphene substrates, and our findings provide mechanistic evidence for the biological activities of graphene, especially in view of graphene-stem cell interactions.

CK1 inhibitor affects in vitro maturation and developmental competence of bovine oocytes

The objectives of present study were to evaluate the effect of casein kinase 1 (CK1) inhibition D4476 on in vitro maturation (IVM) and developmental competence of bovine oocytes. The cumulus oocyte complexes (COCs) were cultured in maturation medium with D4476 (0, 2, 5, 10, 20 μM) for 24 hr. After IVM and in vitro fertilization, through expansion average scores of cumulus cells (CCs), oocyte maturation efficiency, cleavage rate and blastocyst rate of zygote, we found 5 μM D4476 could increase the development potential of oocytes. After the COCs were treated with 5 μM D4476, the results of quantitative real-time PCR analysis, Lichen red staining and PI staining showed that under without affecting germinal vesicle breakdown and nuclear morphology, D4476 could significantly decrease CK1 and upregulate TCF-4 in oocytes. Furthermore, without influencing the level of Bad and CTSB, D4476 could significantly increase the expression of β-catenin, TCF-4, Cx43, MAPK, PTGS-2, PTX-3, TGS-6, Bax and Bcl-2 in CCs. Western blot analysis revealed that the addition of 5 μM D4476 during the maturation of COCs resulted in a lower level of Cx43 protein at 12 hr and a higher expression of Cx43 protein at 24 hr compared to the group without D4476. These results indicate that adding optimum D4476 (5 μM) to maturation medium is beneficial to maturity efficiency and development competence of bovine oocytes.

Overexpression of miR-27b-3p Targeting Wnt3a Regulates the Signaling Pathway of Wnt/β-Catenin and Attenuates Atrial Fibrosis in Rats with Atrial Fibrillation

MicroRNAs (miRNAs) are regarded as a potential method for the treatment of atrial fibrillation (AF) although its molecular mechanism remains unknown. We found in our previous study that the level of peripheral blood miR-27b-3p and the expression of atrial tissue CX43 were both significantly downregulated in AF patients. In the present study, we propose and test this hypothesis that overexpression of miR-27b-3p attenuates atrial fibrosis, increases CX43 expression, and regulates the signaling pathway of Wnt/β-Catenin by targeting Wnt3a. miR-27b-3p overexpression was induced by rat tail vein injection of adeno-associated virus. Two weeks after transfection of adeno-associated virus, the rat AF model was established by tail vein injection of acetylcholine- (ACh-) CaCl₂ for 7 days, and 1 ml/kg was injected daily. The incidence and duration of AF were recorded with an electrocardiogram. Cardiac function was monitored by cardiac ultrasound. Serum cardiac enzyme was detected by ELISA. The expression of atrial miR-27b-3 and Wnt3a was assayed by quantitative RT-PCR. Atrial fibrosis was determined by Masson's trichrome staining. Expression of atrial Collagen-I and Collagen-III was tested by the immunohistochemical method. Expression of CX43 was measured by immunofluorescence. The expression of Collagen-I, a-SMA, Collagen-III, TGF-β1, CX43, Wnt3a, β-Catenin, and p-β-Catenin was assayed by western blot. Our results showed that miR-27b-3p overexpression could reduce the incidence and duration of AF, alleviate atrial fibrosis, increase atrial CX43 expression, and decrease the expression of Collagen-I, a-SMA, Collagen-III, TGF-β1, Wnt3a, and p-β-Catenin. In addition, the results of luciferase activity assay showed that Wnt3a is a validated miR-27b-3p target in HEK 293T cells. Our results provide a new evidence that miR-27b-3p regulates the signaling pathway of Wnt/β-Catenin by targeting Wnt3a, which may play an important role in the development of atrial fibrosis and AF.

Transcription factor 7 functions as an unfavorable prognostic marker of glioblastoma multiforme by promoting proliferation by upregulating c-Myc

Transcription factor 7 (TCF7) is an oncogenic transcription factor in several kinds of cancers. However, the clinical significance of TCF7 in glioblastoma multiforme (GBM) has not been well elucidated. A total of 107 patients with surgical resection of GBM were enrolled in our study. TCF7 expression in these cases was detected by immunohistochemistry and the difference in TCF7 mRNA levels between tumor tissues and adjacent tissues was compared with a real-time PCR. The correlation between TCF7 expression and the clinicopathologic factors was analyzed using the χ-test. Moreover, the prognostic value of TCF7 was evaluated by univariate and multivariate analyses. In addition, the influence of TCF7 on the proliferation of the GBM cell line U251 was detected using an MTT assay after regulating TCF7 and its target gene c-Myc. The high and low expressions of TCF7 accounted for 54.21 and 45.79%, respectively, in all cases. The mRNA level of TCF7 in GBM tissues was markedly higher than that in adjacent tissues, indicating the oncogenic role of TCF7 in GBM. High expression of TCF7 was associated significantly with high Ki67 percentage and the sex of the patients, and it was identified as an independent prognostic factor for patients with GBM. With experiments in vitro, TCF7 was shown to promote cell proliferation by increasing c-Myc expression in GBM. TCF7 could be considered an independent prognostic factor in GBM, and could enhance GBM cell proliferation by upregulating c-Myc, indicating that it may be a potential and promising molecular drug target for GBM.

Skeletal muscle-specific Prmt1 deletion causes muscle atrophy via deregulation of the PRMT6-FOXO3 axis

Protein arginine methyltransferases (PRMTs) have emerged as important regulators of skeletal muscle metabolism and regeneration. However, the direct roles of the various PRMTs during skeletal muscle remodeling remain unclear. Using skeletal muscle-specific prmt1 knockout mice, we examined the function and downstream targets of PRMT1 in muscle homeostasis. We found that muscle-specific PRMT1 deficiency led to muscle atrophy. PRMT1-deficient muscles exhibited enhanced expression of a macroautophagic/autophagic marker LC3-II, FOXO3 and muscle-specific ubiquitin ligases, TRIM63/MURF-1 and FBXO32, likely contributing to muscle atrophy. The mechanistic study reveals that PRMT1 regulates FOXO3 through PRMT6 modulation. In the absence of PRMT1, increased PRMT6 specifically methylates FOXO3 at arginine 188 and 249, leading to its activation. Finally, we demonstrate that PRMT1 deficiency triggers FOXO3 hyperactivation, which is abrogated by PRMT6 depletion. Taken together, PRMT1 is a key regulator for the PRMT6-FOXO3 axis in the control of autophagy and protein degradation underlying muscle maintenance. Abbreviations: Ad-RNAi: adenovirus-delivered small interfering RNA; AKT: thymoma viral proto-oncogene; AMPK: AMP-activated protein kinase; Baf A1: bafilomycin A₁; CSA: cross-sectional area; EDL: extensor digitorum longus; FBXO32: F-box protein 32; FOXO: forkhead box O; GAS: gatrocnemieus; HDAC: histone deacetylase; IGF: insulin-like growth factor; LAMP: lysosomal-associated membrane protein; MAP1LC3B/LC3B: microtubule-associated protein 1 light chain 3 beta; mKO: Mice with skeletal muscle-specific deletion of Prmt1; MTOR: mechanistic target of rapamycin kinase; MYH: myosin heavy chain; MYL1/MLC1f: myosin, light polypeptide 1; PRMT: protein arginine N-methyltransferase; sgRNA: single guide RNA; SQSTM1: sequestosome 1; SOL: soleus; TA: tibialis anterior; TRIM63/MURF-1: tripartite motif-containing 63; YY1: YY1 transcription factor.

Cardiac specific PRMT1 ablation causes heart failure through CaMKII dysregulation

Dysregulation of Ca²⁺/calmodulin-dependent protein kinase (CaMK)II is closely linked with myocardial hypertrophy and heart failure. However, the mechanisms that regulate CaMKII activity are incompletely understood. Here we show that protein arginine methyltransferase 1 (PRMT1) is essential for preventing cardiac CaMKII hyperactivation. Mice null for cardiac PRMT1 exhibit a rapid progression to dilated cardiomyopathy and heart failure within 2 months, accompanied by cardiomyocyte hypertrophy and fibrosis. Consistently, PRMT1 is downregulated in heart failure patients. PRMT1 depletion in isolated cardiomyocytes evokes hypertrophic responses with elevated remodeling gene expression, while PRMT1 overexpression protects against pathological responses to neurohormones. The level of active CaMKII is significantly elevated in PRMT1-deficient hearts or cardiomyocytes. PRMT1 interacts with and methylates CaMKII at arginine residues 9 and 275, leading to its inhibition. Accordingly, pharmacological inhibition of CaMKII restores contractile function in PRMT1-deficient mice. Thus, our data suggest that PRMT1 is a critical regulator of CaMKII to maintain cardiac function.

The mechanisms that regulate the activity of Ca^2 +/calmodulin-dependent protein kinase II (CaMKII) in the context of heart failure are incompletely understood. Here the authors show that protein arginine methyltransferase 1 (PRMT1) prevents cardiac hyperactivation of CaMKII and heart failure development by methylating CaMKII at arginine residues 9 and 275.

A minimally invasive approach to induce myocardial infarction in mice without thoracotomy

Acute myocardial infarction (MI) is a leading cause of morbidity and mortality in the world. Traditional method to induce MI by left coronary artery (LCA) ligation is typically performed by an invasive approach that requires ventilation and thoracotomy, causing serious injuries in animals undergoing this surgery. We attempted to develop a minimally invasive method (MIM) to induce MI in mice. Under the guide of ultrasound, LCA ligation was performed in mice without ventilation and chest-opening. Compared to sham mice, MIM induced MI in mice as determined by triphenyltetrazolium chloride staining and Masson staining. Mice with MIM surgery revealed the reductions of LVEF, LVFS, E/A and ascending aorta (AAO) blood flow, and the elevations of S-T segment and serum cTn-I levels at 24 post-operative hours. The effects of MI induced by MIM were comparable to the effects of MI produced by traditional method in mice. Importantly, MIM increased the survival rates and caused less inflammation after the surgery of LCA ligation, compared to the surgery of traditional method. Further, MIM induced angiogenesis and apoptosis in ischaemic hearts from mice at postoperative 28 days as similarly as traditional method did. Finally, the MIM model was able to develop into the myocardial ischaemia/reperfusion model by using a balloon catheter with minor modifications. The MI model is able to be efficiently induced by a minimally invasive approach in mice without ventilation and chest-opening. This new model is potentially to be used in studying ischaemia-related heart diseases.

Cardiovascular Disease: An Introduction

Cardiovascular disease (CVD) is a collective term designating all types of affliction affecting the blood circulatory system, including the heart and vasculature, which, respectively, displaces and conveys the blood.

Calcium sensing receptor protects high glucose-induced energy metabolism disorder via blocking gp78-ubiquitin proteasome pathway

Diabetic cardiomyopathy (DCM) is a major complication and fatal cause of the patients with diabetes. The calcium sensing receptor (CaSR) is a G protein-coupled receptor, which is involved in maintaining calcium homeostasis, regulating cell proliferation and apoptosis, and so on. In our previous study, we found that CaSR expression, intracellular calcium levels and cardiac function were all significantly decreased in DCM rats; however, the exact mechanism are not clear yet. The present study revealed the protective role of CaSR in myocardial energy metabolism disorder induced by high glucose (HG) as well as the underlying mechanism. Here, we demonstrated that HG decreased the expression of CaSR, mitochondrial fusion proteins (Mfn1, Mfn2), cell gap junction related proteins (Cx43, β-catenin, N-cadherin), and intracellular ATP concentration. In contrast, HG increased extracellular ATP concentration, the expression of gp78, mitochondrial fission proteins (Fis1, Drp1), and the ubiquitination levels of Mfn1, Mfn2 and Cx43. Moreover, CaSR agonist and gp78-siRNA significantly reduced the above changes. Taken together, these results suggest that HG induces myocardial energy metabolism disorder via decrease of CaSR expression, and activation of gp78-ubiquitin proteasome system. In turn, these effects disrupt the structure and function of the mitochondria and the cell gap junction, result in the reduced ATP synthesis and the increased ATP leakage. Stimulation of CaSR significantly attenuates HG-induced abnormal myocardial energy metabolism, suggesting CaSR would be a promising potential therapeutic target for DCM.