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Stappenbeck, F.

Publications and source records attributed to Stappenbeck, F..

2 recordsLinked to original sources

Disruption of the NTCP-EGFR receptor complex as a strategy for selective inhibition of hepatitis B and D virus entry

Hepatitis B and D virus (HBV, HDV) enter hepatocytes through a coordinated process mediated by a receptor complex consisting of sodium taurocholate co transporting polypeptide (NTCP) and its entry cofactors, including epidermal growth factor receptor (EGFR). Here, we established an in vitro assay to evaluate the NTCP-EGFR interaction and identified Oxy229, an oxysterol-based compound that disrupted this molecular interaction. Oxy229 selectively inhibited HBV and HDV infection to HepG2-NTCP cells and primary human hepatocytes. Mechanistic analysis revealed that Oxy229 impaired the relocalization of the HBV-NTCP complex from plasma membrane to intracellular vesicles. Notably, Oxy229 did not compromise the physiological functions of NTCP and EGFR, i.e., bile acid transport and activation of downstream EGFR signaling pathways including Ras-MAPK and PI3K-Akt pathways, indicating selective inhibition of viral entry. Compound derivative analysis identified Oxy283, which acquired dual inhibitory activity against both NTCP-EGFR interaction and NTCP multimerization, resulting in enhanced anti-HBV potency. These findings establish the functional significance of the NTCP-receptor complex formation in HBV/HDV entry and highlight this machinery as a potential target for antiviral intervention.

microbiology↗

Identification of anti-severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) oxysterol derivatives in vitro

Development of effective antiviral drugs targeting the severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) are urgently needed to combat the coronavirus disease 2019 (COVID-19). Oxysterols, defined as oxidized derivatives of cholesterol, include endogenous (naturally occurring) cholesterol metabolites as well as semi-synthetic oxysterol derivatives. We have previously studied the use of semi-synthetic oxysterol derivatives as drug candidates for inhibition of cancer, fibrosis, and bone regeneration. In this study, we have screened a panel of naturally occurring and semi-synthetic oxysterol derivatives for anti-SARS-CoV-2 activity, using a cell culture infection assay. We show that the natural oxysterols, 7-ketocholesterol, 22(R)-hydroxycholesterol, 24(S)-hydroxycholesterol, and 27-hydroxycholesterol, substantially inhibited SARS-CoV-2 propagation in cultured cells. Among semi-synthetic oxysterols, Oxy186 displayed antiviral activity comparable to natural oxysterols. In addition, related oxysterol analogues Oxy210 and Oxy232 displayed more robust anti-SARS-CoV-2 activities, reducing viral replication more than 90% at 10 M and 99% at 15 M, respectively. When orally administered in mice, peak plasma concentrations of Oxy210 fall into a therapeutically relevant range (19 M), based on the dose-dependent curve for antiviral activity in our cell culture infection assay. Mechanistic studies suggest that Oxy210 reduced replication of SARS-CoV-2 with disrupting the formation of double membrane vesicles (DMVs), intracellular membrane compartments associated with viral replication. Oxy210 also inhibited the replication of hepatitis C virus, another RNA virus whose replication is associated with DMVs, but not the replication of the DMV-independent hepatitis D virus. Our study warrants further evaluation of Oxy210 and Oxy232 as a safe and reliable oral medication, which could help protect vulnerable populations with increased risk developing COVID-19.

microbiology↗