scholarly journals Binding of Nanoparticles Harboring Recombinant Large Surface Protein of Hepatitis B Virus to Scavenger Receptor Class B Type 1

Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1334
Author(s):  
Shuji Hinuma ◽  
Kazuyo Fujita ◽  
Shun’ichi Kuroda
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Fluorescent Protein ◽  
Scavenger Receptor ◽  
Density Lipoprotein ◽  
Surface Protein ◽  
Scavenger Receptor Class ◽  
B Virus ◽  
Class B

(1) Background: As nanoparticles containing the hepatitis B virus (HBV) large (L) surface protein produced in yeast are expected to be useful as a carrier for targeting hepatocytes, they are also referred to as bio-nanocapsules (BNCs). However, a definitive cell membrane receptor for BNC binding has not yet been identified. (2) Methods: By utilizing fluorescence-labeled BNCs, we examined BNC binding to the scavenger receptor class B type 1 (SR-B1) expressed in HEK293T cells. (3) Results: Analyses employing SR-B1 siRNA and expression of SR-B1 fused with a green fluorescent protein (SR-B1-GFP) indicated that BNCs bind to SR-B1. As mutagenesis induced in the SR-B1 extracellular domain abrogates or attenuates BNC binding and endocytosis via SR-B1 in HEK293T cells, it was suggested that the ligand-binding site of SR-B1 is similar or close among high-density lipoprotein (HDL), silica, liposomes, and BNCs. On the other hand, L protein was suggested to attenuate an interaction between phospholipids and SR-B1. (4) Conclusions: SR-B1 can function as a receptor for binding and endocytosis of BNCs in HEK293T cells. Being expressed various types of cells, it is suggested that functions as a receptor for BNCs not only in HEK293T cells but also in other types of cells.

scholarly journals Binding of Hepatitis B Virus Pre-S1 Domain-Derived Synthetic Myristoylated Peptide to Scavenger Receptor Class B Type 1 with Differential Properties from Sodium Taurocholate Cotransporting Polypeptide

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 105
Author(s):  
Shuji Hinuma ◽  
Shun’ichi Kuroda
Keyword(s):  
Hepatitis B Virus ◽  
Hepatitis B ◽  
Scavenger Receptor ◽  
Sodium Taurocholate ◽  
Laser Scanning Microscopy ◽  
Scavenger Receptor Class ◽  
B Virus ◽  
Class B ◽  
Differential Properties

(1) Background: The myristoylated pre-S1 peptide (Myr47) synthesized to mimic pre-S1 domain (2-48) in large (L) surface protein of hepatitis B virus (HBV) prevents HBV infection to hepatocytes by binding to sodium taurocholate cotransporting polypeptide (NTCP). We previously demonstrated that yeast-derived nanoparticles containing L protein (bio-nanocapsules: BNCs) bind scavenger receptor class B type 1 (SR-B1). In this study, we examined the binding of Mry47 to SR-B1. (2) Methods: The binding and endocytosis of fluorescence-labeled Myr47 to SR-B1 (and its mutants)-green fluorescence protein (GFP) fusion proteins expressed in HEK293T cells were analyzed using flow cytometry and laser scanning microscopy (LSM). Various ligand-binding properties were compared between SR-B1-GFP and NTCP-GFP. Furthermore, the binding of biotinylated Myr47 to SR-B1-GFP expressed on HEK293T cells was analyzed via pull-down assays using a crosslinker and streptavidin-conjugated beads. (3) Conclusions: SR-B1 bound not only Myr47 but also its myristoylated analog and BNCs, but failed to bind a peptide without myristoylation. However, NTCP only bound Myr47 among the ligands tested. Studies using SR-B1 mutants suggested that both BNCs and Myr47 bind to similar sites of SR-B1. Crosslinking studies indicated that Myr47 binds preferentially SR-B1 multimer than monomer in both HEK293T and HepG2 cells.

Abstract 407: High Density Lipoprotein Mediated Protection of Macrophages Against Apoptosis Requires Scavenger Receptor Class B Type 1 Activity and Sphingosine-1-Phosphate

2017 ◽  
Vol 37 (suppl_1) ◽  
Author(s):  
Kevin Chathely ◽  
Leticia González ◽  
Bernardo Trigatti
Keyword(s):  
High Density Lipoprotein ◽  
Fluorescent Microscopy ◽  
Scavenger Receptor ◽  
Density Lipoprotein ◽  
High Density ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Scavenger Receptor Class ◽  
Class B ◽  
Sphingosine 1 Phosphate

Background/Objectives: Prevention of macrophage apoptosis in advanced atherosclerotic lesions can help stop atherosclerosis progression to vulnerable plaques. High density lipoprotein (HDL) can protect macrophages from apoptosis that has been induced by a variety of agents. We hypothesize that this is the consequence of the sphingolipid, sphingosine-1-phosphate (S1P), specifically carried by HDL, and transferred to S1P receptor 1 (S1PR1) on the cells via the HDL receptor, scavenger receptor class B type 1 (SR-B1). Methods: Apoptosis was induced in murine peritoneal macrophages from wild type and different knockout mice with the ER stress inducing agent tunicamycin. Apoptosis was then observed and detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling through fluorescent microscopy. All experiments were conducted with an n of 3 or 4. Results: Treatment of cells with HDL protected them against tunicamycin induced apoptosis. In contrast, pre-treatment of HDL with S1P lyase, which irreversibly cleaves S1P, eliminated the ability of HDL to protect macrophages. Furthermore, HDL-dependent protection of macrophages against apoptosis required both the HDL receptor SRB1 and the S1PR1. Inhibitor of SRB1’s lipid transport activity also prevented HDL dependant protection against apoptosis. Conclusions: These results suggest that the HDL mediated protection of macrophages against apoptosis may involve SRB1 mediated delivery of S1P from HDL to the S1PR1. Understanding the mechanisms by which HDL elicits atheroprotective signalling in macrophages will provide insight into new targets for therapeutic intervention.

scholarly journals HDL protects against doxorubicin-induced cardiotoxicity in a scavenger receptor class B type 1-, PI3K-, and Akt-dependent manner

2018 ◽  
Vol 314 (1) ◽  
pp. H31-H44 ◽  
Author(s):  
Kristina K. Durham ◽  
Kevin M. Chathely ◽  
Kei Cheng Mak ◽  
Abdul Momen ◽  
Cyrus T. Thomas ◽  
...  
Keyword(s):  
Side Effects ◽  
High Density Lipoprotein ◽  
Cardiac Dysfunction ◽  
Scavenger Receptor ◽  
Density Lipoprotein ◽  
Scavenger Receptor Class ◽  
Class B ◽  
Induced Apoptosis

Doxorubicin is a widely used chemotherapeutic with deleterious cardiotoxic side effects. HDL has been shown to protect cardiomyocytes in vitro against doxorubicin-induced apoptosis. Scavenger receptor class B type 1 (SR-B1), a high-affinity HDL receptor, mediates cytoprotective signaling by HDL through Akt. Here, we assessed whether increased HDL levels protect against doxorubicin-induced cardiotoxicity in vivo and in cardiomyocytes in culture and explored the intracellular signaling mechanisms involved, particularly the role of SR-B1. Transgenic mice with increased HDL levels through overexpression of human apolipoprotein A1 (apoA1Tg/Tg) and wild-type mice (apoA1+/+) with normal HDL levels were treated repeatedly with doxorubicin. After treatment, apoA1+/+mice displayed cardiac dysfunction, as evidenced by reduced left ventricular end-systolic pressure and +dP/d t, and histological analysis revealed cardiomyocyte atrophy and increased cardiomyocyte apoptosis after doxorubicin treatment. In contrast, apoA1Tg/Tgmice were protected against doxorubicin-induced cardiac dysfunction and cardiomyocyte atrophy and apoptosis. When SR-B1 was knocked out, however, overexpression of apoA1 did not protect against doxorubicin-induced cardiotoxicity. Using primary neonatal mouse cardiomyocytes and human immortalized ventricular cardiomyocytes in combination with genetic knockout, inhibitors, or siRNA-mediated knockdown, we demonstrated that SR-B1 is required for HDL-mediated protection of cardiomyocytes against doxorubicin-induced apoptosis in vitro via a pathway involving phosphatidylinositol 3-kinase and Akt1/2. Our findings provide proof of concept that raising apoA1 to supraphysiological levels can dramatically protect against doxorubicin-induced cardiotoxicity via a pathway that is mediated by SR-B1 and involves Akt1/2 activation in cardiomyocytes.NEW & NOTEWORTHY We have identified an important role for the scavenger receptor class B type 1 in facilitating high-density lipoprotein-mediated protection of cardiomyocytes against stress-induced apoptosis and shown that increasing plasma high-density lipoprotein protects against the deleterious side effects of the chemotherapeutic and cardiotoxic drug doxorubicin.

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