scholarly journals Selective hepatitis B and D virus entry inhibitors from the group of pentacyclic lupane-type betulin-derived triterpenoids

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Michael Kirstgen ◽  
Kira Alessandra Alicia Theresa Lowjaga ◽  
Simon Franz Müller ◽  
Nora Goldmann ◽  
Felix Lehmann ◽  
...  
Keyword(s):  
Bile Acid ◽  
Hepatitis B ◽  
Treatment Options ◽  
Receptor Function ◽  
Acid Transport ◽  
Virus Binding ◽  
Virus Receptor ◽  
Bile Acid Transport ◽  
Entry Inhibitors

AbstractCurrent treatment options against hepatitis B and D virus (HBV/HDV) infections have only limited curative effects. Identification of Na+/taurocholate co-transporting polypeptide (NTCP) as the high-affinity hepatic receptor for both viruses in 2012 enables target-based development of HBV/HDV cell-entry inhibitors. Many studies already identified appropriate NTCP inhibitors. However, most of them interfere with NTCP’s physiological function as a hepatic bile acid transporter. To overcome this drawback, the present study aimed to find compounds that specifically block HBV/HDV binding to NTCP without affecting its transporter function. A novel assay was conceptualized to screen for both in parallel; virus binding to NTCP (measured via binding of a preS1-derived peptide of the large HBV/HDV envelope protein) and bile acid transport via NTCP. Hits were subsequently validated by in vitro HDV infection studies using NTCP-HepG2 cells. Derivatives of the birch-derived pentacyclic lupane-type triterpenoid betulin revealed clear NTCP inhibitory potency and selectivity for the virus receptor function of NTCP. Best performing compounds in both aspects were 2, 6, 19, and 25. In conclusion, betulin derivatives show clear structure–activity relationships for potent and selective inhibition of the HBV/HDV virus receptor function of NTCP without tackling its physiological bile acid transport function and therefore are promising drug candidates.

scholarly journals Mutational Analysis of the GXXXG/A Motifs in the Human Na+/Taurocholate Co-Transporting Polypeptide NTCP on Its Bile Acid Transport Function and Hepatitis B/D Virus Receptor Function

2021 ◽  
Vol 8 ◽  
Author(s):  
Massimo Palatini ◽  
Simon Franz Müller ◽  
Kira Alessandra Alicia Theresa Lowjaga ◽  
Saskia Noppes ◽  
Jörg Alber ◽  
...  
Keyword(s):  
Bile Acid ◽  
Hepatitis B ◽  
Mutational Analysis ◽  
Hbv Infection ◽  
Hek293 Cells ◽  
Intact Protein ◽  
Receptor Function ◽  
Acid Transport ◽  
Wild Type ◽  
Bile Acid Transport

Homodimerization is essential for plasma membrane sorting of the liver bile acid transporter NTCP and its function as Hepatitis B/D Virus (HBV/HDV) receptor. However, the protein domains involved in NTCP dimerization are unknown. NTCP bears two potential GXXXG/A dimerization motifs in its transmembrane domains (TMDs) 2 and 7. The present study aimed to analyze the role of these GXXXG/A motifs for the sorting, function, and dimerization of NTCP. The NTCP mutants G60LXXXA64L (TMD2), G233LXXXG237L (TMD7) and a double mutant were generated and analyzed for their interaction with wild-type NTCP using a membrane-based yeast-two hybrid system (MYTH) and co-immunoprecipitation (co-IP). In the MYTH system, the TMD2 and TMD7 mutants showed significantly lower interaction with the wild-type NTCP. In transfected HEK293 cells, membrane expression and bile acid transport activity were slightly reduced for the TMD2 mutant but were completely abolished for the TMD7 and the TMD2/7 mutants, while co-IP experiments still showed intact protein-protein interactions. Susceptibility for in vitro HBV infection in transfected HepG2 cells was reduced to 50% for the TMD2 mutant, while the TMD7 mutant was not susceptible for HBV infection at all. We conclude that the GXXXG/A motifs in TMD2 and even more pronounced in TMD7 are important for proper folding and sorting of NTCP, and so indirectly affect glycosylation, homodimerization, and bile acid transport of NTCP, as well as its HBV/HDV receptor function.

scholarly journals Long-term trans-inhibition of the hepatitis B and D virus receptor NTCP by taurolithocholic acid

2020 ◽  
Author(s):  
Kira Alessandra AT Lowjaga ◽  
Michael Kirstgen ◽  
Simon F Müller ◽  
Nora Goldmann ◽  
Felix Lehmann ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Bile Acid ◽  
Hepatitis B ◽  
Inhibitory Effect ◽  
Hek293 Cells ◽  
Transport Function ◽  
Receptor Function ◽  
Secondary Bile Acid ◽  
Entry Inhibitors

Human hepatic bile acid transporter Na+/taurocholate co-transporting polypeptide (NTCP) represents the liver-specific entry receptor for the Hepatitis B and D Viruses (HBV/HDV). Chronic hepatitis B and D affect several million people worldwide, but treatment options are limited. Recently, HBV/HDV entry inhibitors targeting NTCP have emerged as promising novel drug candidates. Nevertheless, the exact molecular mechanism that NTCP uses to mediate virus binding and entry into hepatocytes is still not completely understood. It is already known that human NTCP mRNA expression is down-regulated under cholestasis. Furthermore, incubation of rat hepatocytes with the secondary bile acid taurolithocholic acid (TLC) triggers internalization of the rat Ntcp protein from the plasma membrane. In the present study, the long-term inhibitory effect of TLC on transport function, HBV/HDV receptor function and membrane expression of human NTCP were analyzed in HepG2 and HEK293 cells stably overexpressing NTCP. Even after short pulse preincubation, TLC had a significant long-lasting inhibitory effect on the transport function of NTCP, but the NTCP protein was still present at the plasma membrane. Furthermore, binding of the HBV/HDV myr-preS1 peptide and susceptibility for in vitro HDV infection were significantly reduced by TLC preincubation. We hypothesize that TLC rapidly accumulates in hepatocytes and mediates long-lasting trans-inhibition of the transport and receptor function of NTCP via a particular TLC binding site at an intracellularly accessible domain of NTCP. Physiologically, this trans-inhibition might protect hepatocytes from toxic overload of bile acids. Pharmacologically, it provides an interesting novel NTCP target site for potential long-acting HBV/HDV entry inhibitors.

scholarly journals Primary Bile Acid Malabsorption: Defective In Vitro Ileal Active Bile Acid Transport

1982 ◽  
Vol 83 (4) ◽  
pp. 804-811 ◽  
Author(s):  
James E. Heubi ◽  
William F. Balistreri ◽  
Joseph D. Fondacaro ◽  
John C. Partin ◽  
William K. Schubert
Keyword(s):  
Bile Acid ◽  
Acid Transport ◽  
Bile Acid Transport ◽  
Bile Acid Malabsorption ◽  
Primary Bile Acid

scholarly journals The solute carrier family 10 (SLC10): Beyond bile acid transport

2013 ◽  
Vol 34 (2-3) ◽  
pp. 252-269 ◽  
Author(s):  
Tatiana Claro da Silva ◽  
James E. Polli ◽  
Peter W. Swaan
Keyword(s):  
Bile Acid ◽  
Solute Carrier Family ◽  
Acid Transport ◽  
Bile Acid Transport ◽  
Solute Carrier

Abnormal hepatic sinusoidal bile acid transport: New insights into the pathogenesis of cholestasis?

2001 ◽  
Vol 120 (1) ◽  
pp. 321-322 ◽  
Author(s):  
Michael Trauner ◽  
Peter Fickert ◽  
Gernot Zollner
Keyword(s):  
Bile Acid ◽  
Acid Transport ◽  
Bile Acid Transport

scholarly journals Hepatitis D Virus Entry Inhibitors Based on Repurposing Intestinal Bile Acid Reabsorption Inhibitors

Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 666
Author(s):  
Michael Kirstgen ◽  
Kira Alessandra Alicia Theresa Lowjaga ◽  
Simon Franz Müller ◽  
Nora Goldmann ◽  
Felix Lehmann ◽  
...  
Keyword(s):  
Bile Acid ◽  
Taurocholic Acid ◽  
Hek293 Cells ◽  
Acid Uptake ◽  
Hepatitis D ◽  
Entry Inhibitors ◽  
Ic50 Values ◽  
Bile Acid Transporter ◽  
Acid Transporter

Identification of Na+/taurocholate co-transporting polypeptide (NTCP) as high-affinity hepatic entry receptor for the Hepatitis B and D viruses (HBV/HDV) opened the field for target-based development of cell-entry inhibitors. However, most of the HBV/HDV entry inhibitors identified so far also interfere with the physiological bile acid transporter function of NTCP. The present study aimed to identify more virus-selective inhibitors of NTCP by screening of 87 propanolamine derivatives from the former development of intestinal bile acid reabsorption inhibitors (BARIs), which interact with the NTCP-homologous intestinal apical sodium-dependent bile acid transporter (ASBT). In NTCP-HEK293 cells, the ability of these compounds to block the HBV/HDV-derived preS1-peptide binding to NTCP (virus receptor function) as well as the taurocholic acid transport via NTCP (bile acid transporter function) were analyzed in parallel. Hits were subsequently validated by performing in vitro HDV infection experiments in NTCP-HepG2 cells. The most potent compounds S985852, A000295231, and S973509 showed in vitro anti-HDV activities with IC50 values of 15, 40, and 70 µM, respectively, while the taurocholic acid uptake inhibition occurred at much higher IC50 values of 24, 780, and 490 µM, respectively. In conclusion, repurposing of compounds from the BARI class as novel HBV/HDV entry inhibitors seems possible and even enables certain virus selectivity based on structure-activity relationships.

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