Inhibitory effect of presenilin inhibitor LY411575 on maturation of hepatitis C virus core protein, production of the viral particle and expression of host proteins involved in pathogenicity

Abstract

Hepatitis C virus (HCV) core protein is responsible for the formation of infectious viral particles and induction of pathogenicity. The C-terminal transmembrane region of the immature core protein is cleaved by signal peptide peptidase (SPP) for maturation of the core protein. SPP belongs to the family of presenilin-like aspartic proteases. Some presenilin inhibitors are expected to suppress HCV infection and production; however, this anti-HCV effect has not been investigated in detail. In this study, presenilin inhibitors were screened to identify anti-HCV compounds. Of the 13 presenilin inhibitors tested, LY411575 was the most potent inhibitor of SPP-dependent cleavage of HCV core protein. Production of intracellular core protein and supernatant infectious viral particles from HCV-infected cells was significantly impaired by LY411575 in a dose-dependent manner (half maximum inhibitory concentration = 0.27 μM, cytotoxic concentration of the extracts to cause death to 50% of viable cells > 10 μM). No effect of LY411575 on intracellular HCV RNA in the subgenomic replicon cells was detected. LY411575 synergistically promoted daclatasvir-dependent inhibition of viral production, but not that of viral replication. Furthermore, LY411575 inhibited HCV-related production of reactive oxygen species and expression of NADPH oxidases and vascular endothelial growth factor. Taken together, our data suggest that LY411575 suppresses HCV propagation through SPP inhibition and impairs host gene expressions related to HCV pathogenicity.

Interferon gamma inhibits the differentiation of mouse adult liver and bone marrow hematopoietic stem cells by inhibiting the activation of notch signaling

“…The GSI, LY-411,575 (a mixture of four diasteriomers of a small molecule inhibitor of γ-secretase), was synthesized as described previously [34]. Six-week-old male C57BL/6 J mice received a gavage of GSI (10 mg/kg/d dissolved in dimethyl sulfoxide (DMSO), resuspended in 50 mL of corn oil).…”

Establishment of a Cell Culture Model Permissive for Infection by Hepatitis B and C Viruses

“…The human embryonic kidney (HEK) 293T cell line, human hepatoma Huh7-derived cell lines, and HepG2 cell lines were maintained in Dulbecco's modified Eagle's medium (DMEM; Sigma-Aldrich, St. Louis, MO), supplemented with 10% fetal bovine serum (FBS; Gibco, Cambrex, MD), nonessential amino acids (Sigma-Aldrich), sodium pyruvate (Sigma-Aldrich), 100 U/mL penicillin, and 100 μg/mL streptomycin (Gibco). (6,7,15,16) Huh7-derived and HepG2-derived cell lines harboring HCV replicon RNAs were maintained in culture medium supplemented with 0.5 mg/mL or 1.0 mg/mL G418 (Nacalai Tesque, Kyoto, Japan), respectively. HepG2derived cell lines stably expressing human NTCP or CD81 were maintained in the presence of 1 µg/mL puromycin (Nacalai Tesque) or 400 µg/mL zeocin (Invitrogen, Carlsbad, CA), respectively.…”

“…Huh7 cells and their derivatives are generally maintained in DMEM-based medium for HCV infection, (7,11,12) whereas HepG2-derived cell lines are cultured in primary maintenance medium (PMM) or DMEM/F-12 (F-12)-based medium for HBV infection. (9,13,16,20) The medium compositions are listed in Supporting Table S1.…”

“…HBV and HCV infections have been shown to induce the expression of several host factors, such as cyclooxygenase-2 (COX-2), vascular endothelial growth factor (VEGF), inducible nitric oxide synthase, Wnt family member 1, fatty acid synthase, and sterol regulatory element binding protein-1, which are implicated in carcinogenesis and lipogenesis. (7,(24)(25)(26) Thus, we investigated whether coinfection (HCV superinfection) could alter the expression of these genes in G2BC-C2 cells. The expression of COX-2 was up-regulated by HBV infection under the treatment with JAK inhibitor, but not by HCV infection, regardless of the treatment (Fig.…”

“…It is difficult to elucidate the virological aspects of HBV/HCV coinfection, as distributed reliable models for in vitro coinfection are not established. Hepatoma cell lines, including Huh7 and others, have generally been used because of their permissiveness to HCV infection and to replication (6,7) ; however, these cell lines are not susceptible to HBV infection. The Huh7 cell line is permissive for HBV replication and viral particle formation, but not to events related to viral uncoating and replication due to the lack of unidentified host factor(s).…”