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2.
Nature ; 583(7817): 615-619, 2020 07.
Article in English | MEDLINE | ID: mdl-32494007

ABSTRACT

Pneumonia resulting from infection is one of the leading causes of death worldwide. Pulmonary infection by the respiratory syncytial virus (RSV) is a large burden on human health, for which there are few therapeutic options1. RSV targets ciliated epithelial cells in the airways, but how viruses such as RSV interact with receptors on these cells is not understood. Nucleolin is an entry coreceptor for RSV2 and also mediates the cellular entry of influenza, the parainfluenza virus, some enteroviruses and the bacterium that causes tularaemia3,4. Here we show a mechanism of RSV entry into cells in which outside-in signalling, involving binding of the prefusion RSV-F glycoprotein with the insulin-like growth factor-1 receptor, triggers the activation of protein kinase C zeta (PKCζ). This cellular signalling cascade recruits nucleolin from the nuclei of cells to the plasma membrane, where it also binds to RSV-F on virions. We find that inhibiting PKCζ activation prevents the trafficking of nucleolin to RSV particles on airway organoid cultures, and reduces viral replication and pathology in RSV-infected mice. These findings reveal a mechanism of virus entry in which receptor engagement and signal transduction bring the coreceptor to viral particles at the cell surface, and could form the basis of new therapeutics to treat RSV infection.


Subject(s)
Receptor, IGF Type 1/metabolism , Receptors, Virus/metabolism , Respiratory Syncytial Viruses/metabolism , Virus Internalization , Cell Line , Cell Nucleus/metabolism , Enzyme Activation , Humans , Membrane Fusion/drug effects , Phosphoproteins/metabolism , Protein Binding , Protein Kinase C/antagonists & inhibitors , Protein Kinase C/metabolism , RNA-Binding Proteins/metabolism , Receptor, IGF Type 1/antagonists & inhibitors , Respiratory Syncytial Viruses/drug effects , Respiratory Syncytial Viruses/pathogenicity , Respiratory Syncytial Viruses/physiology , Viral Load/drug effects , Virus Internalization/drug effects , Nucleolin
3.
Chem Asian J ; 15(1): 91-97, 2020 Jan 02.
Article in English | MEDLINE | ID: mdl-31778040

ABSTRACT

The properties of eumelanin-like particles (EMPs) and pheomelanin-like particles (PMPs) in regulating the process of amyloid formation of amyloid-beta 42 (Aß42) were examined. EMPs and PMPs are effective both in interfering with amyloid aggregation of Aß42 and in remodeling matured Αß42 fibers. The results suggest that some (but not all) molecular species consisting of melanin-like particles (MPs) are responsible for their inhibiting property toward amyloid formation, and the influence is likely manifested by long-range interactions. Incubating preformed Aß42 fibers with catechols or MPs leads to the formation of mesh-like, interconnected Aß42 fibers encapsulated with melanin-like material. MPs are kinetically more effective than catechol monomers in this process, and a detailed investigation reveals that 4,5-dihydroxyindole, a major intermediate in the formation of melanin-like species, and its derivatives are mainly responsible for remodeling amyloid fibers.


Subject(s)
Amyloid beta-Peptides/chemistry , Amyloid beta-Peptides/metabolism , Melanins/pharmacology , Peptide Fragments/chemistry , Peptide Fragments/metabolism , Protein Aggregates/drug effects , Protein Aggregation, Pathological , Dose-Response Relationship, Drug , Humans , Melanins/chemical synthesis , Melanins/chemistry , Particle Size , Structure-Activity Relationship , Surface Properties
4.
Sci Rep ; 8(1): 11372, 2018 07 27.
Article in English | MEDLINE | ID: mdl-30054560

ABSTRACT

L-Ascorbic acid (vitamin C, AA) exhibits anti-cancer effects with high-dose treatment through the generation of reactive oxygen species (ROS) and selective damage to cancer cells. The anti-cancer effects of L-ascorbic acid are determined by sodium-dependent vitamin C transporter 2 (SVCT-2), a transporter of L-ascorbic acid. In this study, we demonstrate that L-ascorbic acid treatment showed efficient anti-cancer activity in cell lines with high expression levels of SVCT-2 for a gradient concentration of L-ascorbic acid from 10 µM -2 mM. However, in low SVCT-2 expressing cell lines, high-dose L-ascorbic acid (>1 mM) showed anti-cancer effects but low-dose (<10 µM) treatment induced cell proliferation. Such conflicting results that depend on the concentration are called a hormetic dose response. A hormetic dose response to low-dose L-ascorbic acid was also observed in high SVCT-2 expressing cell lines in the presence of a SVCT family inhibitor. Insufficient uptake of L-ascorbic acid in low SVCT-2 expressing cancer cell lines cannot generate sufficient ROS to kill cancer cells, resulting in the hormetic response. Molecular analysis confirmed the increased expression of cancer proliferation markers in the hormetic dose response. These results suggest that L-ascorbic exhibits a biphasic effect in cancer cells depending on SVCT-2 expression.


Subject(s)
Antineoplastic Agents/pharmacology , Ascorbic Acid/pharmacology , Colorectal Neoplasms/metabolism , Hormesis , Sodium-Coupled Vitamin C Transporters/metabolism , Apoptosis/drug effects , Apoptosis/genetics , Cell Line, Tumor , Cell Proliferation/drug effects , Colorectal Neoplasms/genetics , Colorectal Neoplasms/pathology , Gene Expression Regulation, Neoplastic/drug effects , Hormesis/drug effects , Humans , Models, Biological , Reactive Oxygen Species/metabolism
5.
Cell Biochem Funct ; 34(5): 317-25, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27151289

ABSTRACT

The lymphatic vascular system plays an important role in tissue fluid homeostasis. Lymphedema is a chronic, progressive, and incurable condition that leads to lymphatic fluid retention; it may be primary (heritable) or secondary (acquired) in nature. Although there is a growing understanding of lymphedema, methods for the prevention and treatment of lymphedema are still limited. In this study, we investigated differential protein expressions in sham-operated and lymphedema-operated mice for 3 days, using two-dimensional gel electrophoresis (2-DE) and mass spectrometry analysis. Male improved methodology for culturing noninbred (ICR) mice developed lymphedema in the right hindlimb. Twenty functional proteins were found to be differentially expressed between lymphedema induced-right leg tissue and normal left leg tissue. Out of these proteins, the protein levels of apolipoprotein A-1 preprotein, alpha-actinin-3, mCG21744, parkinson disease, serum amyloid P-component precursor, annexin A8, mKIAA0098 protein, and fibrinogen beta chain precursor were differentially upregulated in the lymphedema mice compared with the sham-operated group. Western blotting analysis was used to validate the proteomics results. Our results showing differential up-regulation of serum amyloid P-component precursor, parkinson disease, and apolipoprotein A-1 preprotein in lymphedema model over sham-operated model suggest important insights into pathophysiological target for lymphedema. Copyright © 2016 John Wiley & Sons, Ltd.


Subject(s)
Lymphedema/metabolism , Lymphedema/pathology , Proteomics/methods , Animals , Blotting, Western , Disease Models, Animal , Electrophoresis, Gel, Two-Dimensional , Hindlimb/pathology , Male , Mice, Inbred ICR , Proteome/metabolism , Reproducibility of Results
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