scholarly journals Cellular receptors for enterovirus A71

2020 ◽  
Vol 27 (1) ◽  
Author(s):  
Kyousuke Kobayashi ◽  
Satoshi Koike
Keyword(s):  
Cell Surface ◽  
Heparan Sulfate ◽  
Neurological Diseases ◽  
Enterovirus 71 ◽  
Trna Synthetase ◽  
Heparan Sulfate Proteoglycans ◽  
Health Concern ◽  
Dependent Manner ◽  
Surface Binding

AbstractEnterovirus 71 (EV-A71) is one of the major causative agents of hand, foot, and mouth disease. EV-A71 infection is sometimes associated with severe neurological diseases such as acute encephalitis, acute flaccid paralysis, and cardiopulmonary failure. Therefore, EV-A71 is a serious public health concern. Scavenger receptor class B, member 2 (SCARB2) is a type III transmembrane protein that belongs to the CD36 family and is a major receptor for EV-A71. SCARB2 supports attachment and internalization of the virus and initiates conformational changes that lead to uncoating of viral RNA in the cytoplasm. The three-dimensional structure of the virus-receptor complex was elucidated by cryo-electron microscopy. Two α-helices in the head domain of SCARB2 bind to the G-H loop of VP1 and the E-F loop of VP2 capsid proteins of EV-A71. Uncoating takes place in a SCARB2- and low pH-dependent manner. In addition to SCARB2, other molecules support cell surface binding of EV-A71. Heparan sulfate proteoglycans, P-selectin glycoprotein ligand-1, sialylated glycan, annexin II, vimentin, fibronectin, and prohibitin enhance viral infection by retaining the virus on the cell surface. These molecules are known as “attachment receptors” because they cannot initiate uncoating. In vivo, SCARB2 expression was observed in EV-A71 antigen-positive neurons and epithelial cells in the crypts of the palatine tonsils in patients that died of EV-A71 infection. Adult mice are not susceptible to infection by EV-A71, but transgenic mice that express human SCARB2 become susceptible to EV-A71 infection and develop neurological diseases similar to those observed in humans. Attachment receptors may also be involved in EV-A71 infection in vivo. Although heparan sulfate proteoglycans are expressed by many cultured cell lines and enhance infection by a subset of EV-A71 strains, they are not expressed by cells that express SCARB2 at high levels in vivo. Thus, heparan sulfate-positive cells merely adsorb the virus and do not contribute to replication or dissemination of the virus in vivo. In addition to these attachment receptors, cyclophilin A and human tryptophanyl aminoacyl-tRNA synthetase act as an uncoating regulator and an entry mediator that can confer susceptibility to non-susceptibile cells in the absence of SCARB2, respectively. The roles of attachment receptors and other molecules in EV-A71 pathogenesis remain to be elucidated.

DEK Regulates Hematopoietic Stem and Progenitor Cell Fate By Activating AKT and ERK Mediated Signaling through CXCR2/Heparan Sulfate Proteoglycans

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 2645-2645
Author(s):  
Maegan L. Capitano ◽  
Nirit Mor-Vaknin ◽  
Maureen Legendre ◽  
Scott Cooper ◽  
David Markovitz ◽  
...  
Keyword(s):  
Heparan Sulfate ◽  
Pertussis Toxin ◽  
Progenitor Cell ◽  
Heparan Sulfate Proteoglycans ◽  
Regulatory Function ◽  
Hematopoietic Progenitor Cell ◽  
Dependent Manner ◽  
Hematopoietic Stem ◽  
Phosphorylated Akt

Abstract DEK is a nuclear DNA-binding protein that has been implicated in the regulation of transcription, DNA repair, mRNA processing, and chromatin remodeling. Endogenous DEK regulates hematopoiesis, as bone marrow (BM) from DEK-/- mice manifest increased hematopoietic progenitor cell (HPC) numbers and cycling status and decreased long-term (LT) and secondary hematopoietic stem cell (HSC) engrafting capability (Broxmeyer et al., 2012 & 2013). DEK is also secreted and found in extracellular spaces. We recently demonstrated that extracellular DEK decreases the number and cycling status of CFU-GM, BFU-E, and CFU-GEMM in vivo and in vitro. Of importance, in vivo administration of recombinant mouse (rm)DEK significantly increased the number of phenotypic LT-HSC.Moreover, DEK significantly enhanced the ex vivo expansion of rigorously-defined and functional HSC of human CD34+ cord blood (CB) and mouse lineage negative BM cells. This suggests that DEK may enhance HSC numbers by blocking the production of HPC and thus acting as a fate determinant. Upon finding that DEK has a Glu-Leu-Arg (ELR) motif, similar to that of CXC chemokines such as IL-8, we explored whether exogenous DEK functioned by signaling through CXCR2, the receptor that binds and mediates ELR+ CXC chemokine function. By blocking CXCR2 and utilizing CXCR2-/- BM, we demonstrated that DEK regulation of HPC and HSC numbers is CXCR2-dependent. New studies now show that DEK signals through Gai-protein coupled receptor signaling; pretreating BM cells with pertussis toxin inhibited DEK's regulatory function in HPCs, a process unique to DEK as other ELR+ CXC chemokines (i.e. IL-8) were insensitive to the inhibitory effects of pertussis toxin. To determine which CXCR2-mediated signaling pathway DEK utilizes, we performed intracellular staining of mouse BM cells for phosphorylated AKT, ERK1/2, p38MAPK, and STAT3 following 15, 30, and 60 minute stimulation with rmDEK; rmSCF, rhSDF1a and rhIL-8 were used as positive controls. DEK stimulated phosphorylation of AKT and ERK1/2, but not p38MAPK or STAT3 in phenotypically-defined HSCs, a process blocked when BM cells were pretreated with CXCR2 neutralizing antibody, suggesting that DEK induces signaling through CXCR2. Activation of AKT can lead to NF-kB p65 translocation from the cytoplasm to the nucleus and intracellular DEK has been implicated in regulating this process in HeLa cells (Sammons et al., 2006). However, using ImageStream we saw no NF-kB p65 translocation in DEK-treated BM HSCs as compared to a TNFa positive control. We previously showed that DEK binds heparan sulfate proteoglycans (HSPGs; Saha et al., 2014). DEK also functions in an HSPG-dependent manner to regulate HPC and HSC numbers. HSPGs are important in chemokine signaling as they help in chemokine presentation. Blocking DEK's ability to bind to HSPGs by pretreating BM cells with heparin blocked DEK-mediated phosphorylation of ERK1/2 and AKT in HSCs, suggesting that HSPGs are also important in DEK-mediated CXCR2 signaling. DEK-/- BM LSK cells can internalize extracellular rmDEK, resulting in an increase in the heterochromatin marker H3K9Me3 in the nucleus. We now know that this process is dependent on the ability of DEK to bind to HSPGs and be internalized since the trimethylation of H3K9 is inhibited by pretreating cells with heparin or with Pitstop2, an inhibitor of HSPG-mediated endocytosis. This process is independent of CXCR2, as blocking CXCR2 does not inhibit the increases in H3K9Me3 seen in the nucleus of DEK-/- LSK cells following DEK treatment. These data suggest that DEK utilizes HSPGs in two separate ways: 1) as a co-receptor to mediate CXCR2 signaling and 2) as a means to endocytose DEK, leading to heterochromatin stabilization. Disclosures Broxmeyer: CordUse: Other: SAB Member .

scholarly journals Hepatocyte Heparan Sulfate Is Required for Adeno-Associated Virus 2 but Dispensable for Adenovirus 5 Liver TransductionIn Vivo

2015 ◽  
Vol 90 (1) ◽  
pp. 412-420 ◽  
Author(s):  
Anne K. Zaiss ◽  
Erin M. Foley ◽  
Roger Lawrence ◽  
Lina S. Schneider ◽  
Hamidreza Hoveida ◽  
...  
Keyword(s):  
Cell Surface ◽  
Heparan Sulfate ◽  
Coagulation Factor ◽  
Heparan Sulfate Proteoglycans ◽  
Factor X ◽  
Primary Hepatocytes ◽  
Adeno Associated Virus ◽  
Fold Reduction ◽  
Adenovirus 5

ABSTRACTAdeno-associated virus 2 (AAV2) and adenovirus 5 (Ad5) are promising gene therapy vectors. Both display liver tropism and are currently thought to enter hepatocytesin vivothrough cell surface heparan sulfate proteoglycans (HSPGs). To test directly this hypothesis, we created mice that lackExt1, an enzyme required for heparan sulfate biosynthesis, in hepatocytes.Ext1HEPmutant mice exhibit an 8-fold reduction of heparan sulfate in primary hepatocytes and a 5-fold reduction of heparan sulfate in whole liver tissue. Conditional hepatocyteExt1gene deletion greatly reduced AAV2 liver transduction following intravenous injection. Ad5 transduction requires blood coagulation factor X (FX); FX binds to the Ad5 capsid hexon protein and bridges the virus to HSPGs on the cell surface. Ad5.FX transduction was abrogated in primary hepatocytes fromExt1HEPmice. However, in contrast to the case with AAV2, Ad5 transduction was not significantly reduced in the livers ofExt1HEPmice. FX remained essential for Ad5 transductionin vivoinExt1HEPmice. We conclude that while AAV2 requires HSPGs for entry into mouse hepatocytes, HSPGs are dispensable for Ad5 hepatocyte transductionin vivo. This study reopens the question of how adenovirus enters cellsin vivo.IMPORTANCEOur understanding of how viruses enter cells, and how they can be used as therapeutic vectors to manage disease, begins with identification of the cell surface receptors to which viruses bind and which mediate viral entry. Both adeno-associated virus 2 and adenovirus 5 are currently thought to enter hepatocytesin vivothrough heparan sulfate proteoglycans (HSPGs). However, direct evidence for these conclusions is lacking. Experiments presented herein, in which hepatic heparan sulfate synthesis was genetically abolished, demonstrated that HSPGs are not likely to function as hepatocyte Ad5 receptorsin vivo. The data also demonstrate that HSPGs are required for hepatocyte transduction by AAV2. These results reopen the question of the identity of the Ad5 receptorin vivoand emphasize the necessity of demonstrating the nature of the receptor by genetic means, both for understanding Ad5 entry into cellsin vivoand for optimization of Ad5 vectors as therapeutic agents.

scholarly journals Extracellular distribution of diffusible growth factors controlled by heparan sulfate proteoglycans during mammalian embryogenesis

2014 ◽  
Vol 369 (1657) ◽  
pp. 20130545 ◽  
Author(s):  
Isao Matsuo ◽  
Chiharu Kimura-Yoshida
Keyword(s):  
Growth Factors ◽  
Cell Surface ◽  
Heparan Sulfate ◽  
Cell Fate ◽  
Heparan Sulfate Proteoglycans ◽  
Target Cells ◽  
Dependent Manner ◽  
Mammalian Development ◽  
Morphogenetic Protein ◽  
And Control

During mouse embryogenesis, diffusible growth factors, i.e. fibroblast growth factors, Wnt, bone morphogenetic protein and Hedgehog family members, emanating from localized areas can travel through the extracellular space and reach their target cells to specify the cell fate and form tissue architectures in coordination. However, the mechanisms by which these growth factors travel great distances to their target cells and control the signalling activity as morphogens remain an enigma. Recent studies in mice and other model animals have revealed that heparan sulfate proteoglycans (HSPGs) located on the cell surface (e.g. syndecans and glypicans) and in the extracellular matrix (ECM; e.g. perlecan and agrin) play crucial roles in the extracellular distribution of growth factors. Principally, the function of HSPGs depends primarily on the fine features and localization of their heparan sulfate glycosaminoglycan chains. Cell-surface-tethered HSPGs retain growth factors as co-receptors and/or endocytosis mediators, and enzymatic release of HSPGs from the cell membrane allows HSPGs to transport or move multiple growth factors. By contrast, ECM-associated HSPGs function as a reservoir or barrier in a context-dependent manner. This review is focused on our current understanding of the extracellular distribution of multiple growth factors controlled by HSPGs in mammalian development.

scholarly journals Unacylated ghrelin binds heparan-sulfate proteoglycans which modulate its function

2020 ◽  
Author(s):  
Patric Jd Delhanty ◽  
Martin Huisman ◽  
Karina Prins ◽  
Jacobie Steenbergen ◽  
Rosinda Mies ◽  
...  
Keyword(s):  
Cell Surface ◽  
Heparan Sulfate ◽  
Mcf7 Cell ◽  
Biological Effects ◽  
Heparan Sulfate Proteoglycans ◽  
Surface Proteins ◽  
Cell Surface Receptor ◽  
Cell Surfaces ◽  
Growth Hormone Secretagogue

Acylated ghrelin (AG) is a gut-derived peptide with growth hormone secretagogue (GHS), orexigenic and other physiological activities mediated by GHS receptor-1a (GHSR). Ghrelin occurs in unacylated form (UAG) with activities opposing AG, although its mechanism of action is unknown. UAG does not antagonize AG at GHSR, and has biological effects on cells that lack this receptor. Because UAG binds to cells, it has been hypothesized that UAG acts via a cell-surface receptor, although this has not been confirmed. This study aimed to identify cell surface proteins to which UAG binds that could modulate or mediate its biological effects. The MCF7 cell-line was used as a model because UAG induces ERK signaling in these cells in the absence of GHSR. Using ligand-receptor capture and LC-MS/MS we identified specific heparan-sulfate proteoglycans (HSPGs) to which UAG interacts on cell surfaces. In line with this, UAG, as well as AG, bind with high affinity to heparin, and heparin and heparinase treatment suppress, whereas HSPG overexpression increases, UAG binding to MCF7 cell surfaces. Moreover, heparin suppresses the ERK response to UAG. However, conversion of the lysines in UAG to alanine, which prevent its binding to heparin and cell surface HSPGs, does not prevent its activation of ERK. Our data show that the interaction of UAG with HSPGs modulates its biological activity in cells. More broadly, the interaction of UAG and AG with HSPGs could be important for the specificity and potency of their biological action in vivo.

Chickpea (Cicer arietinum L.) Lectin Exhibit Inhibition of ACE-I, α-amylase and α-glucosidase Activity

2019 ◽  
Vol 26 (7) ◽  
pp. 494-501 ◽  
Author(s):  
Sameer Suresh Bhagyawant ◽  
Dakshita Tanaji Narvekar ◽  
Neha Gupta ◽  
Amita Bhadkaria ◽  
Ajay Kumar Gautam ◽  
...  
Keyword(s):  
Biological Effects ◽  
Exchange Chromatography ◽  
Health Concern ◽  
Carbohydrate Binding ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Ic50 Values ◽  
Chickpea Lectin

Background: Diabetes and hypertension are the major health concern and alleged to be of epidemic proportions. This has made it a numero uno subject at various levels of investigation. Glucosidase inhibitor provides the reasonable option in treatment of Diabetes Mellitus (DM) as it specifically targets post prandial hyperglycemia. The Angiotensin Converting Enzyme (ACE) plays an important role in hypertension. Therefore, inhibition of ACE in treatment of elevated blood pressure attracts special interest of the scientific community. Chickpea is a food legume and seeds contain carbohydrate binding protein- a lectin. Some of the biological properties of this lectin hitherto been elucidated. Methods: Purified by ion exchange chromatography, chickpea lectin was tested for its in vitro antioxidant, ACE-I inhibitory and anti-diabetic characteristic. Results: Lectin shows a characteristic improvement over the synthetic drugs like acarbose (oral anti-diabetic drug) and captopril (standard antihypertensive drug) when, their IC50 values are compared. Lectin significantly inhibited α-glucosidase and α-amylase in a concentration dependent manner with IC50 values of 85.41 ± 1.21 ҝg/ml and 65.05 ± 1.2 µg/ml compared to acarbose having IC50 70.20 ± 0.47 value of µg/ml and 50.52 ± 1.01 µg/ml respectively. β-Carotene bleaching assay showed antioxidant activity of lectin (72.3%) to be as active as Butylated Hydroxylanisole (BHA). In addition, lectin demonstrated inhibition against ACE-I with IC50 value of 57.43 ± 1.20 µg/ml compared to captopril. Conclusion: Lectin demonstrated its antioxidant character, ACE-I inhibition and significantly inhibitory for α-glucosidase and α-amylase seems to qualify as an anti-hyperglycemic therapeutic molecule. The biological effects of chickpea lectin display potential for reducing the parameters of medically debilitating conditions. These characteristics however needs to be established under in vivo systems too viz. animals through to humans.

scholarly journals Vaccinia Virus Envelope H3L Protein Binds to Cell Surface Heparan Sulfate and Is Important for Intracellular Mature Virion Morphogenesis and Virus Infection In Vitro and In Vivo

2000 ◽  
Vol 74 (7) ◽  
pp. 3353-3365 ◽  
Author(s):  
Chi-Long Lin ◽  
Che-Sheng Chung ◽  
Hans G. Heine ◽  
Wen Chang
Keyword(s):  
Cell Surface ◽  
Vaccinia Virus ◽  
Heparan Sulfate ◽  
Mutant Virus ◽  
Wild Type Virus ◽  
Type Virus ◽  
Wild Type ◽  
Virion Morphogenesis

ABSTRACT An immunodominant antigen, p35, is expressed on the envelope of intracellular mature virions (IMV) of vaccinia virus. p35 is encoded by the viral late gene H3L, but its role in the virus life cycle is not known. This report demonstrates that soluble H3L protein binds to heparan sulfate on the cell surface and competes with the binding of vaccinia virus, indicating a role for H3L protein in IMV adsorption to mammalian cells. A mutant virus defective in expression of H3L (H3L−) was constructed; the mutant virus has a small plaque phenotype and 10-fold lower IMV and extracellular enveloped virion titers than the wild-type virus. Virion morphogenesis is severely blocked and intermediate viral structures such as viral factories and crescents accumulate in cells infected with the H3L− mutant virus. IMV from the H3L− mutant virus are somewhat altered and less infectious than wild-type virions. However, cells infected by the mutant virus form multinucleated syncytia after low pH treatment, suggesting that H3L protein is not required for cell fusion. Mice inoculated intranasally with wild-type virus show high mortality and severe weight loss, whereas mice infected with H3L− mutant virus survive and recover faster, indicating that inactivation of the H3L gene attenuates virus virulence in vivo. In summary, these data indicate that H3L protein mediates vaccinia virus adsorption to cell surface heparan sulfate and is important for vaccinia virus infection in vitro and in vivo. In addition, H3L protein plays a role in virion assembly.

scholarly journals Distinct glycosaminoglycan chain length and sulfation patterns required for cellular uptake of Tau, Aβ, and α-Synuclein

2017 ◽  
Author(s):  
Barbara E. Stopschinski ◽  
Brandon B. Holmes ◽  
Gregory M. Miller ◽  
Jaime Vaquer-Alicea ◽  
Linda C. Hsieh-Wilson ◽  
...  
Keyword(s):  
Cell Surface ◽  
Neurodegenerative Diseases ◽  
Heparan Sulfate ◽  
Chain Length ◽  
Cellular Uptake ◽  
Genetic Manipulation ◽  
Heparan Sulfate Proteoglycans ◽  
Cell Uptake ◽  
Major Genes

AbstractTranscellular propagation of aggregate “seeds” has been proposed to mediate progression of neurodegenerative diseases in tauopathies and α-synucleinopathies. We have previously determined that tau and α-synuclein aggregates bind heparan sulfate proteoglycans (HSPGs) on the cell surface. This mediates uptake and intracellular seeding. The specificity and mode of binding to HSPGs has been unknown. We used modified heparins to determine the size and sulfation requirements of glycosaminoglycan (GAGs) binding to aggregates in biochemical and cell uptake and seeding assays. Aggregates of tau require a precise GAG architecture with defined sulfate moieties in the N- and 6-O-positions, whereas α-synuclein and Aβ rely slightly more on overall charge on the GAGs. To determine the genetic requirements for aggregate uptake, we individually knocked out the major genes of the HSPG synthesis pathway using CRISPR/Cas9 in HEK293T cells. Knockout of EXT1, EXT2 and EXTL3, N-sulfotransferase (NDST1), and 6-O-sulfotransferase (HS6ST2) significantly reduced tau uptake. α-Synuclein was not sensitive to HS6ST2 knockout. Good correlation between pharmacologic and genetic manipulation of GAG binding by tau and α-synuclein indicates specificity that may help elucidate a path to mechanism-based inhibition of transcellular propagation of pathology.

Inhibition of leukocyte locomotion by hyaluronic acid

1981 ◽  
Vol 48 (1) ◽  
pp. 315-331
Author(s):  
J.V. Forrester ◽  
P.C. Wilkinson
Keyword(s):  
Molecular Weight ◽  
Visual Analysis ◽  
Cell Movement ◽  
Chemotactic Factor ◽  
Major Constituent ◽  
Dependent Manner ◽  
Surface Binding ◽  
Micropore Filter

The effect of hyaluronate on neutrophil motility in vitro was studied by the micropore filter technique and by direct visual analysis of the locomotion of neutrophils on glass. Both directed and random locomotion of neutrophils was inhibited by physiological concentrations (0.5-6.0 mg ml(−1)) of hyaluronate in a dose- and molecular weight-dependent manner. Inhibition of cell movement was more pronounced for high molecular weight chemoattractants such as casein than for small chemotactic peptides such as f-Met-Leu-Phe. Chemotactic factor gradient formation in filter chambers was profoundly retarded by hyaluronate, which may partly explain the inhibitory effects of hyaluronate on directed neutrophil locomotion. In addition, hyaluronate inhibited the binding of chemotactic factor to the neutrophil surface. This effect, together with a reduction in cell-to-substratum adhesion, may provide an additional explanation for hyaluronate-induced inhibition of random neutrophil locomotion. Inhibition of locomotion by hyaluronate was easily reversed by washing the cells free of hyaluronate; thus competition by hyaluronate for cell-surface binding sites is unlikely, and physical effects such as steric exclusion or molecular sieving by the large hyaluronate polymer provide the most probable explanations of its inhibitory effect on cell locomotion. Since hyaluronate is a major constituent of tissue matrices, these results draw attention to the importance of the extracellular environment in regulating inflammatory cell movement in vivo.

scholarly journals Antiobesity Effects of Extract from Spergularia marina Griseb in Adipocytes and High-Fat Diet-Induced Obese Rats

Nutrients ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 336 ◽  
Author(s):  
Yong-Hyun Park ◽  
Jae-Joon Lee ◽  
Hee-Kyoung Son ◽  
Bok-Hee Kim ◽  
Jaemin Byun ◽  
...  
Keyword(s):  
Ethanol Extract ◽  
Health Concern ◽  
Dependent Manner ◽  
High Fat ◽  
Proliferation And Differentiation ◽  
Obese Rats ◽  
Spergularia Marina ◽  
Natural Herb

Obesity has recently risen and become a serious health concern in Korea according to the westernized diet and altered lifestyle. Hence, there is a growing interest in the supplementation of phytochemicals to find a safe and effective functional ingredient to treat obesity. Spergularia marina Griseb (SM) has traditionally been used as a natural herb against chronic diseases in Korea. In this study, we investigated the antiobesity effects of SM in vitro and in vivo. SM ethanol extract (SME) inhibited proliferation and differentiation in murine adipocytes and primary porcine pre-adipocytes in a dose-dependent manner. In the in vivo study, supplementation of SM powder (SMP) remarkably attenuated fat accumulation in HFD-induced obese rats. In addition, SMP supplementation improved lipid profiles in the serum and tissues of high-fat induced obese rats. Collectively, these data indicated that SME exhibited antiobesity effects by modulating adipogenesis and lipolysis. Furthermore, SMP could be developed as an obesity-induced metabolic syndrome treatment.

Sign in / Sign up

Export Citation Format

Share Document