Biology subjects

Sureau, C.

Publications and source records attributed to Sureau, C..

5 recordsLinked to original sources

bioRxiv2026

Ritonavir-Induced Cellular Stress Alters Viral HBs Glycoprotein Biogenesis and Production of Infectious Hepatitis D Virions

Chronic co-infections by HBV and its satellite virus HDV are associated with a high risk of progression to cirrhosis and liver cancer, and therapeutic options for achieving a cure are still unsatisfactory. HBs is the main surface glycoprotein of both viruses, and is also massively secreted by infected hepatocytes in the form of empty subviral particles which suppress the host immune responses. This makes HBs an attractive target to develop therapeutic strategies. Here, we took advantage of the known interaction between the Large form HDV antigen (HDAg-L) and the small form of HBs (S-HBs) to develop a non-infectious, minimalistic reporter assay for the assembly and secretion of HDV particles. By screening the existing pharmacopeia for drugs that could interfere with S-HBs and HDAg-L co-secretion, we found that ritonavir and other Cytochrome P450 inhibitors affect the biogenesis of HBs and impair the production of infectious HDV virions. Mechanistically, we established that these drugs induce oxidative stress which dysregulates disulfide bond formation in the endoplasmic reticulum. As a consequence, the production of HBs, which depends on a dense network of disulfide bonds, is markedly affected as evidenced by an abnormal glycosylation profile, altered antigenic properties, and a poor expression of the largest form of HBs (L-HBs) which is essential to virus entry into target cells. This is associated with induction of the unfolded protein response, with the upregulation of CHOP/DDIT3 and key enzymes involved in the synthesis of the reducing metabolite glutathione (PHGDH, SHMT2, MTHFD2). Overall, our results indicate that alterations in redox homeostasis significantly impact HBs biogenesis, and reveal a druggable pathway that could be exploited to eliminate HDV in chronically infected patients. IMPACT AND IMPLICATIONSMore effective therapies are still needed to achieve a functional cure in patients chronically co-infected by HBV and HDV. In this study, we discovered that ritonavir, along with other cytochrome P450 inhibitors, can affect the production of infectious HDV particles in human hepatocyte cultures. Mechanistically, ritonavir induces oxidative stress and the unfolded protein response in the endoplasmic reticulum, thereby altering the biogenesis of HBs, the surface glycoprotein of both viruses. This work highlights the potential benefit and mechanism of action of ritonavir and related molecules in the treatment of co-infected patients.

microbiology↗

bioRxiv2021

The kinesin KIF4 mediates HBV/HDV entry through regulation of surface NTCP localization and can be targeted by RXR agonists in vitro.

Intracellular transport via microtubule-based dynein and kinesin family motors plays a key role in viral reproduction and transmission. We show here that Kinesin Family Member 4 (KIF4) plays an important role in HBV/HDV infection. We intended to explore host factors impacting the HBV life cycle that can be therapeutically addressed using siRNA library transfection and HBV/NLuc (HBV/NL) reporter virus infection in HepG2-hNTCP C4 cells. KIF4 silencing resulted in a 3-fold reduction in luciferase activity following HBV/NL infection and suppressed both wild-type HBV and HDV infection. Transient KIF4 depletion reduced surface and raised intracellular NTCP (HBV/HDV entry receptor) levels, according to both cellular fractionation and immunofluorescence analysis (IF). Overexpression of wild-type KIF4 but not ATPase-null KIF4 regains the surface localization of NTCP in these cells. Furthermore, immunofluorescence (IF) revealed KIF4 and NTCP colocalization across microtubule filaments, and a co-immunoprecipitation study showed that KIF4 physically binds to NTCP. KIF4 expression is regulated by FOXM1. Interestingly, we discovered that RXR agonists (Bexarotene, and Alitretinoin) down-regulated KIF4 expression via FOXM1-mediated suppression, resulting in a substantial decrease in HBV-Pre-S1 protein attachment to HepG2-hNTCP cell surface and subsequent suppression of HBV infection in HepG2-hNTCP and primary human hepatocytes (PXB) (Bexarotene, IC50 1.89 {+/-} 0.98 M). Overall, our findings show that human KIF4 is a critical regulator of NTCP surface transport and localization, which is required for NTCP to function as a receptor for HBV/HDV entry. Furthermore, small molecules that suppress or alleviate KIF4 expression would be potential antiviral candidates that target HBV and HDV entry phases. Author SummaryUnderstanding HBV/HDV entry machinery and the mechanism by which NTCP (HBV/HDV entry receptor) surface expression is regulated is crucial to develop antiviral entry inhibitors. We found that NTCP surface transport is mainly controlled by the motor kinesin KIF4. Surprisingly, KIF4 was negatively regulated by RXR receptors through FOXM1-mediated suppression This study not only mechanistically correlated the role of RXR receptors in regulating HBV/HDV entry but also suggested a novel approach to develop therapeutic rexinoids for preventing HBV and/or HDV infections in important clinical situations, such as in patients undergoing liver transplantation or those who are at a high risk of HBV infection and unresponsive to HBV vaccination.

microbiology↗

bioRxiv2021

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↗

bioRxiv2020

Hepatitis B virus envelope proteins can serve as therapeutic targets embedded in the host cell plasma membrane

Hepatitis B virus (HBV) infection is a major health threat causing 880,000 deaths each year. Available therapies control viral replication, but do not cure HBV leaving patients at risk to develop hepatocellular carcinoma. Here we show that HBV envelope proteins (HBs) - besides their integration into endosomal membranes - become embedded in the plasma membrane where they can be targeted by redirected T-cells. HBs was detected on the surface of HBV-infected cells, in livers of mice replicating HBV and in HBV-induced hepatocellular carcinoma. Staining with HBs-specific recombinant antibody MoMab recognizing a confirmational epitope indicated that membrane-associated HBs remains correctly folded in HBV-replicating cells in cell culture and in livers of HBV-transgenic mice in vivo. MoMab coated onto superparamagnetic iron oxide nanoparticles allowed to detect membrane-associated HBs after HBV infection by electron microscopy in distinct stretched of the hepatocyte plasma membrane. Last not least we demonstrate that HBs located to the cell surface allows therapeutic targeting of HBV-positive cells by T-cells either engrafted with a chimeric antigen receptor or redirected by bispecific, T-cell engager antibodies.

microbiology↗

bioRxiv2018

A Single Adaptive Mutation in Sodium Taurocholate Cotransporting Polypeptide Induced by Hepadnaviruses Determines Virus Species-specificity

Hepatitis B virus (HBV) and its hepadnavirus relatives infect a wide range of vertebrates from fish to human. Hepadnaviruses and their hosts have a long history of acquiring adaptive mutations. However, there are no reports providing direct molecular evidence for such a coevolutionary \"arms race\" between hepadnaviruses and their hosts. Here, we present evidence suggesting the adaptive evolution of the sodium taurocholate cotransporting polypeptide (NTCP), an HBV receptor, has been influenced by virus infection. Evolutionary analysis of the NTCP-encoding genes from 20 mammals showed that most NTCP residues are highly conserved among species, exhibiting evolution under negative selection (dN/dS < 1); this observation implies that the evolution of NTCP is restricted by maintaining its original protein function. However, 0.7 % of NTCP amino acid (aa) residues exhibit rapid evolution under positive selection (dN/dS > 1). Notably, a substitution at aa 158, a positively selected residue, converting the human NTCP to a monkey-type sequence abrogated the capacity to support HBV infection; conversely, a substitution at this residue converting the monkey Ntcp to the human sequence was sufficient to confer HBV susceptibility. Together, these observations suggested that positive selection at aa 158 was induced by virus infection. Moreover, the aa 158 sequence determined attachment of the HBV envelope protein to host cell, demonstrating the mechanism whereby HBV infection would create positive selection at this residue in NTCP. In summary, we provide the first evidence in agreement with the function of hepadnavirus as a driver for inducing an adaptive mutation in host receptor.\n\nImportanceHepatitis B virus (HBV) and its hepadnavirus relatives infect a wide range of vertebrates, with a long infectious history (hundreds of millions of years). Such a long history generally allows adaptive mutations in hosts to escape from infection, while simultaneously allowing adaptive mutations in viruses to overcome host barriers. However, there is no published molecular evidence for such a coevolutionary \"arms race\" between hepadnaviruses and hosts. In the present study, we performed coevolutionary phylogenetic analysis between hepadnaviruses and the sodium taurocholate cotransporting polypeptide (NTCP), an HBV receptor, combined with virological experimental assays for investigating the biological significance of NTCP sequence variation. Our data provide the first molecular evidences supporting that HBV-related hepadnaviruses drive adaptive evolution in the NTCP sequence, including a mechanistic explanation of how NTCP mutations determine host viral susceptibility. Our novel insights enhance our understanding of how hepadnaviruses evolved with their hosts, permitting the acquisition of strong species-specificity.

evolutionary biology↗