scholarly journals Ability of Hyaluronidase 2 To Degrade Extracellular Hyaluronan Is Not Required for Its Function as a Receptor for Jaagsiekte Sheep Retrovirus

2007 ◽  
Vol 81 (7) ◽  
pp. 3124-3129 ◽  
Author(s):  
Vladimir Vigdorovich ◽  
A. Dusty Miller ◽  
Roland K. Strong
Keyword(s):  
Recombinant Baculovirus ◽  
Weak Acid ◽  
Cell Entry ◽  
Jaagsiekte Sheep Retrovirus ◽  
Hyaluronidase Activity ◽  
A Cell ◽  
Affinity Interaction ◽  
Entry Receptor ◽  
Inactivating Mutations ◽  
Hyaluronidase 2

ABSTRACT Jaagsiekte sheep retrovirus (JSRV) uses hyaluronidase 2 (Hyal2) as a cell entry receptor. By making inactivating mutations to the catalytic residues of human Hyal2, we found that hyaluronidase activity was dispensable for its receptor function. The affinities of the JSRV envelope glycoprotein for Hyal2 and the Hyal2 mutant were similar, and hyaluronan did not block either high-affinity interaction or virus infection. While generating the Hyal2 mutant, we discovered that our previous analysis of the hyaluronidase activity of Hyal2 was affected by a contaminating hyaluronan lyase, which we have identified as the occlusion-derived baculovirus E66 protein of the recombinant baculovirus used to produce Hyal2. We now report that purified human Hyal2 is a weak acid-active hyaluronidase.

scholarly journals ACE2, TMPRSS2 and L-SIGN expression in placentae from HIV-positive pregnancies exposed to antiretroviral therapy–implications for SARS-CoV-2 placental infection

2021 ◽  
Author(s):  
Smriti Kala ◽  
Ksenia Meteleva ◽  
Lena Serghides
Keyword(s):  
Antiretroviral Therapy ◽  
Pregnant Women ◽  
Viral Entry ◽  
Cell Entry ◽  
Hiv Positive ◽  
Mrna Levels ◽  
Black Race ◽  
Entry Receptor ◽  
Lower Expression ◽  
Human Placentae

Abstract Background SARS-CoV-2 binding receptor ACE2 and the spike protein priming protease TMPRSS2 are co-expressed in human placentae. It is unknown whether their expression is altered in the context of HIV infection and antiretroviral therapy (ART). Methods We compared mRNA levels of SARS-CoV-2 cell-entry mediators ACE2, TMPRSS2 and L-SIGN (an alternative entry receptor) by qPCR in 105 placentae: 45 from pregnant women with HIV (WHIV) exposed to protease inhibitor (PI)-based ART, 17 from WHIV on non-PI-based ART, and 43 from HIV-uninfected women. Results ACE2 levels were lower, while L-SIGN levels were higher in placentae from WHIV on PI-based ART as compared to those on non-PI-based ART and to HIV-uninfected women. TMPRSS2 levels were similar between groups. Black race was significantly associated with lower expression of ACE2 and higher expression of L-SIGN. ACE2 levels were significantly higher in placentae of female fetuses. Discussion We have identified pregnant women of Black race and WHIV who are on PI-based ART to have relatively lower expression of placental ACE2 than those of White race and HIV-uninfected women. This effect may potentially contribute to altered susceptibility to COVID-19 in these women, either favorably; by reduced viral entry, or detrimentally; by loss of ACE2 protection against hyperinflammation.

scholarly journals PEDV Infection Generates Conformation-Specific Antibodies That Can Be Effectively Detected by a Cell-Based ELISA

Viruses ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 303
Author(s):  
Wei-Ting Hsu ◽  
Chia-Yu Chang ◽  
Chih-Hsuan Tsai ◽  
Sung-Chan Wei ◽  
Huei-Ru Lo ◽  
...  
Keyword(s):  
Recombinant Baculovirus ◽  
Immunocytochemical Staining ◽  
Enzyme Linked Immunosorbent Assay ◽  
Serum Samples ◽  
Perfect Agreement ◽  
Specific Antibodies ◽  
Diarrhea Virus ◽  
Serological Studies ◽  
A Cell ◽  
Infected Insect

Porcine epidemic diarrhea virus (PEDV) is a coronavirus that causes serious and highly contagious enteric disease in swine worldwide. In this study, we constructed a recombinant baculovirus (S-Bac) expressing full-length spike protein of the virulent epidemic genotype 2b (G2b) PEDV strain for serological studies of infected pigs. We found that most spike-specific antibodies produced upon PEDV infection in pigs are conformation-specific and they could be detected on S-Bac-infected insect cells by immunofluorescent assay, but they were insensitive to Western blot analysis, the typical method for antiserum analysis. These results indicated that spike conformation is crucial for serum recognition. Since it is difficult to purify trimeric spike membrane protein for conventional enzyme-linked immunosorbent assay (ELISA), we used S-Bac to generate a novel cell-based ELISA for convenient PEDV detection. We analyzed 100 pig serum samples, and our cell-based ELISA exhibited a sensitivity of 100%, a specificity of 97%, and almost perfect agreement [Cohen’s kappa coefficient value (κ) = 0.98] with immunocytochemical staining results. Our cell-based ELISA rapidly presented antigen for proper detection of conformation-specific antibodies, making PEDV detection more convenient, and it will be useful for detecting many viral diseases in the future.

scholarly journals Expression and Characterization of a Soluble, Active Form of the Jaagsiekte Sheep Retrovirus Receptor, Hyal2

2005 ◽  
Vol 79 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Vladimir Vigdorovich ◽  
Roland K. Strong ◽  
A. Dusty Miller
Keyword(s):  
Cell Surface ◽  
Expression System ◽  
Specific Interaction ◽  
Active Form ◽  
Soluble Form ◽  
Viral Inhibition ◽  
Virus Envelope ◽  
Critical Function ◽  
Jaagsiekte Sheep Retrovirus ◽  
Hyaluronidase Activity

ABSTRACT Retrovirus entry into cells is mediated by specific interactions between virus envelope glycoproteins and cell surface receptors. Many of these receptors contain multiple membrane-spanning regions, making their purification and study difficult. The jaagsiekte sheep retrovirus (JSRV) receptor, hyaluronidase 2 (Hyal2), is a glycosylphosphatidylinositol (GPI)-anchored molecule containing no peptide transmembrane regions, making it an attractive candidate for study of retrovirus entry. Further, the hyaluronidase activity reported for human Hyal2, combined with its broad expression pattern, may point to a critical function of Hyal2 in the turnover of hyaluronan, a major extracellular matrix component. Here we describe the properties of a soluble form of human Hyal2 (sHyal2) purified from a baculoviral expression system. sHyal2 is a 54-kDa monomer with weak hyaluronidase activity compared to that of the known hyaluronidase Spam1. In contrast to a previous report indicating that Hyal2 cleaved hyaluronan to a limit product of 20 kDa and was active only at acidic pH, we find that sHyal2 is capable of further degradation of hyaluronan and is active over a broad pH range, consistent with Hyal2 being active at the cell surface where it is normally localized. Interaction of sHyal2 with the JSRV envelope glycoprotein was analyzed by viral inhibition assays, showing >90% inhibition of transduction at 28 nM sHyal2, and by surface plasmon resonance, revealing a remarkably tight specific interaction with a dissociation constant (KD ) of 32 ± 1 pM. In contrast to results obtained with avian retroviruses, purified receptor was not capable of promoting transduction of cells that do not express the virus receptor.

scholarly journals A mammalian homolog of the zebrafish transmembrane protein 2 (TMEM2) is the long-sought-after cell-surface hyaluronidase

2017 ◽  
Vol 292 (18) ◽  
pp. 7304-7313 ◽  
Author(s):  
Hayato Yamamoto ◽  
Yuki Tobisawa ◽  
Toshihiro Inubushi ◽  
Fumitoshi Irie ◽  
Chikara Ohyama ◽  
...  
Keyword(s):  
Cell Surface ◽  
Dermatan Sulfate ◽  
Transmembrane Protein ◽  
Live Cells ◽  
Dependent Manner ◽  
Cellular Functions ◽  
Ph Optimum ◽  
Hyaluronidase Activity ◽  
A Cell ◽  
Intermediate Size

Hyaluronan (HA) is an extremely large polysaccharide (glycosaminoglycan) involved in many cellular functions. HA catabolism is thought to involve the initial cleavage of extracellular high-molecular-weight (HMW) HA into intermediate-size HA by an extracellular or cell-surface hyaluronidase, internalization of intermediate-size HA, and complete degradation into monosaccharides in lysosomes. Despite considerable research, the identity of the hyaluronidase responsible for the initial HA cleavage in the extracellular space remains elusive. HYAL1 and HYAL2 have properties more consistent with lysosomal hyaluronidases, whereas CEMIP/KIAA1199, a recently identified HA-binding molecule that has HA-degrading activity, requires the participation of the clathrin-coated pit pathway of live cells for HA degradation. Here we show that transmembrane protein 2 (TMEM2), a mammalian homolog of a protein playing a role in zebrafish endocardial cushion development, is a cell-surface hyaluronidase. Live immunostaining and surface biotinylation assays confirmed that mouse TMEM2 is expressed on the cell surface in a type II transmembrane topology. TMEM2 degraded HMW-HA into ∼5-kDa fragments but did not cleave chondroitin sulfate or dermatan sulfate, indicating its specificity to HA. The hyaluronidase activity of TMEM2 was Ca2+-dependent; the enzyme's pH optimum is around 6–7, and unlike CEMIP/KIAA1199, TMEM2 does not require the participation of live cells for its hyaluronidase activity. Moreover, TMEM2-expressing cells could eliminate HA immobilized on a glass surface in a contact-dependent manner. Together, these data suggest that TMEM2 is the long-sought-after hyaluronidase that cleaves extracellular HMW-HA into intermediate-size fragments before internalization and degradation in the lysosome.

scholarly journals Mitochondrial uncouplers with an extraordinary dynamic range

2007 ◽  
Vol 407 (1) ◽  
pp. 129-140 ◽  
Author(s):  
Phing-How Lou ◽  
Birgit S. Hansen ◽  
Preben H. Olsen ◽  
Søren Tullin ◽  
Michael P. Murphy ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Adenine Nucleotide ◽  
Weak Acid ◽  
Butylated Hydroxytoluene ◽  
Adenine Nucleotide Translocase ◽  
Covalent Attachment ◽  
Intact Cells ◽  
Starting Point ◽  
Mitochondrial Uncouplers ◽  
Affinity Interaction

We have discovered that some weak uncouplers (typified by butylated hydroxytoluene) have a dynamic range of more than 106in vitro: the concentration giving measurable uncoupling is less than one millionth of the concentration causing full uncoupling. They achieve this through a high-affinity interaction with the mitochondrial adenine nucleotide translocase that causes significant but limited uncoupling at extremely low uncoupler concentrations, together with more conventional uncoupling at much higher concentrations. Uncoupling at the translocase is not by a conventional weak acid/anion cycling mechanism since it is also caused by substituted triphenylphosphonium molecules, which are not anionic and cannot protonate. Covalent attachment of the uncoupler to a mitochondrially targeted hydrophobic cation sensitizes it to membrane potential, giving a small additional effect. The wide dynamic range of these uncouplers in isolated mitochondria and intact cells reveals a novel allosteric activation of proton transport through the adenine nucleotide translocase and provides a promising starting point for designing safer uncouplers for obesity therapy.

scholarly journals Equine Arteritis Virus Uses Equine CXCL16 as an Entry Receptor

2016 ◽  
Vol 90 (7) ◽  
pp. 3366-3384 ◽  
Author(s):  
Sanjay Sarkar ◽  
Lakshman Chelvarajan ◽  
Yun Young Go ◽  
Frank Cook ◽  
Sergey Artiushin ◽  
...  
Keyword(s):  
Transmembrane Protein ◽  
Critical Role ◽  
Equine Arteritis Virus ◽  
Cell Entry ◽  
Significant Advance ◽  
Type I ◽  
Small Interfering Rnas ◽  
Chromosome 11 ◽  
Trade Restrictions ◽  
Entry Receptor

ABSTRACTPrevious studies in our laboratory have identified equine CXCL16 (EqCXCL16) to be a candidate molecule and possible cell entry receptor for equine arteritis virus (EAV). In horses, the CXCL16 gene is located on equine chromosome 11 (ECA11) and encodes a glycosylated, type I transmembrane protein with 247 amino acids. Stable transfection of HEK-293T cells with plasmid DNA carrying EqCXCL16 (HEK-EqCXCL16 cells) increased the proportion of the cell population permissive to EAV infection from <3% to almost 100%. The increase in permissiveness was blocked either by transfection of HEK-EqCXCL16 cells with small interfering RNAs (siRNAs) directed against EqCXCL16 or by pretreatment with guinea pig polyclonal antibody against EqCXCL16 protein (Gp anti-EqCXCL16 pAb). Furthermore, using a virus overlay protein-binding assay (VOPBA) in combination with far-Western blotting, gradient-purified EAV particles were shown to bind directly to the EqCXCL16 proteinin vitro. The binding of biotinylated virulent EAV strain Bucyrus at 4°C was significantly higher in HEK-EqCXCL16 cells than nontransfected HEK-293T cells. Finally, the results demonstrated that EAV preferentially infects subpopulations of horse CD14+monocytes expressing EqCXCL16 and that infection of these cells is significantly reduced by pretreatment with Gp anti-EqCXCL16 pAb. The collective data from this study provide confirmatory evidence that the transmembrane form of EqCXCL16 likely plays a major role in EAV host cell entry processes, possibly acting as a primary receptor molecule for this virus.IMPORTANCEOutbreaks of EVA can be a source of significant economic loss for the equine industry from high rates of abortion in pregnant mares, death in young foals, establishment of the carrier state in stallions, and trade restrictions imposed by various countries. Similar to other arteriviruses, EAV primarily targets cells of the monocyte/macrophage lineage, which, when infected, are believed to play a critical role in EVA pathogenesis. To this point, however, the host-specified molecules involved in EAV binding and entry into monocytes/macrophages have not been identified. Identification of the cellular receptors for EAV may provide insights to design antivirals and better prophylactic reagents. In this study, we have demonstrated that EqCXCL16 acts as an EAV entry receptor in EAV-susceptible cells, equine monocytes. These findings represent a significant advance in our understanding of the fundamental mechanisms associated with the entry of EAV into susceptible cells.

scholarly journals Human Identical Sequences of SARS-CoV-2 Promote Clinical Progression of COVID-19 by Upregulating Hyaluronan via NamiRNA-Enhancer Network

2020 ◽  
Author(s):  
Wei Li ◽  
Shuai Yang ◽  
Peng Xu ◽  
Dapeng Zhang ◽  
Ying Tong ◽  
...  
Keyword(s):  
Distress Syndrome ◽  
Underlying Mechanism ◽  
Cell Entry ◽  
Clinical Progression ◽  
Health Crisis ◽  
Effective Strategies ◽  
Public Health Crisis ◽  
Human Genomic ◽  
Hyaluronan Synthase 2 ◽  
Entry Receptor

SUMMARYThe COVID-19 pandemic is a widespread and deadly public health crisis. The pathogen SARS-CoV-2 replicates in the lower respiratory tract and causes fatal pneumonia. Although tremendous efforts have been put into investigating the pathogeny of SARS-CoV-2, the underlying mechanism of how SARS-CoV-2 interacts with its host is largely unexplored. Here, by comparing the genomic sequences of SARS-CoV-2 and human, we identified five fully conserved elements in SARS-CoV-2 genome, which were termed as “human identical sequences (HIS)”. HIS are also recognized in both SARS-CoV and MERS-CoV genome. Meanwhile, HIS-SARS-CoV-2 are highly conserved in the primate. Mechanically, HIS-SARS-CoV-2, behaving as virus-derived miRNAs, directly target to the human genomic loci and further interact with host enhancers to activate the expression of adjacent and distant genes, including cytokines gene and angiotensin converting enzyme II (ACE2), a well-known cell entry receptor of SARS-CoV-2, and hyaluronan synthase 2 (HAS2), which further increases hyaluronan formation. Noteworthily, hyaluronan level in plasma of COVID-19 patients is tightly correlated with severity and high risk for acute respiratory distress syndrome (ARDS) and may act as a predictor for the progression of COVID-19. HIS antagomirs, which downregulate hyaluronan level effectively, and 4-Methylumbelliferone (MU), an inhibitor of hyaluronan synthesis, are potential drugs to relieve the ARDS related ground-glass pattern in lung for COVID-19 treatment. Our results revealed that unprecedented HIS elements of SARS-CoV-2 contribute to the cytokine storm and ARDS in COVID-19 patients. Thus, blocking HIS-involved activating processes or hyaluronan synthesis directly by 4-MU may be effective strategies to alleviate COVID-19 progression.

Sign in / Sign up

Export Citation Format

Share Document