Methods for Thrips Transmission and Maintenance of Tomato Spotted Wilt Virus (TSWV).

Tomato spotted wilt virus (TSWV) is transmitted by insect pests from the Thripidae family, including Frankliniella occidentalis, commonly known as western flower thrips. For experimental purposes, researchers have developed methods for inoculating host plants with TSWV, allowing thrips to acquire TSWV, and verifying thrips acquisition. Plants can be inoculated with TSWV either mechanically or with thrips in the lab, but in nature, the virus is transmitted by thrips.

Exosomes as Conduits: Facilitating Hepatitis B Virus-Independent Hepatitis D Virus Transmission and Propagation in Hepatocytes.

A number of research studies, including ours, have spotlighted exosomes as critical facilitators of viral dissemination. While hepatitis B virus (HBV) transmission through exosomes has been studied, the focus on its satellite virus, the hepatitis delta virus (HDV), has been unexplored in this context. HDV, although being a defective virus, can replicate its genome autonomously within hepatocytes, independently of HBV.

HepG2BD: A Novel and Versatile Cell Line with Inducible HDV Replication and Constitutive HBV Expression.

Individuals chronically infected with hepatitis B virus (HBV) and hepatitis Delta virus (HDV) present an increased risk of developing cirrhosis and hepatocellular carcinoma in comparison to HBV mono-infected individuals. Although HDV only replicates in individuals coinfected or superinfected with HBV, there is currently no in vitro model that can stably express both viruses simultaneously, mimicking the chronic infections seen in HBV/HDV patients. Here, we present the HepG2BD cell line as a novel in vitro culture system for long-term replication of HBV and HDV.

Pangenomic antiviral effect of REP 2139 in CRISPR/Cas9 engineered cell lines expressing hepatitis B virus surface antigen.

Chronic hepatitis B remains a global health problem with 296 million people living with chronic HBV infection and being at risk of developing cirrhosis and hepatocellular carcinoma. Non-infectious subviral particles (SVP) are produced in large excess over infectious Dane particles in patients and are the major source of Hepatitis B surface antigen (HBsAg). They are thought to exhaust the immune system, and it is generally considered that functional cure requires the clearance of HBsAg from blood of patient.

N-Phenylpyridine-3-Carboxamide and 6-Acetyl-1H-Indazole Inhibit the RNA Replication Step of the Dengue Virus Life Cycle.

Dengue virus (DENV) is a that causes the most prevalent arthropod-borne viral disease. Clinical manifestation of DENV infection ranges from asymptomatic to severe symptoms that can lead to death. Unfortunately, no antiviral treatments against DENV are currently available.

Characterization of the antiviral effects of REP 2139 on the HBV lifecycle in vitro.

During hepatitis B virus (HBV) infection, HBV subviral particles (SVP) are produced in large excess in comparison to infectious virions and account for the major source of HBV surface antigen (HBsAg) in the blood. This abundant circulating HBsAg has been postulated to promote HBV chronicity by inducing immune exhaustion against HBsAg. Nucleic acid polymers (NAPs) such as REP 2139 display promising antiviral activity against both HBV and hepatitis Delta virus (HDV) in clinical trials.

Hepatitis Delta Virus Alters the Autophagy Process To Promote Its Genome Replication.

A substantial number of viruses have been demonstrated to subvert autophagy to promote their own replication. Recent publications have reported the proviral effect of autophagy induction on hepatitis B virus (HBV) replication. Hepatitis delta virus (HDV) is a defective virus and an occasional obligate satellite of HBV.

Revealing Drug Self-Associations into Nano-Entities.

The aqueous properties of the drugs Sorafenib, Lapatinib, Gefitinib, Fulvestrant, and Clofazimine were explored to monitor their tendency to self-associate. A combination of nuclear magnetic resonance, dynamics light scattering, and electron and confocal microscopies found that they tended to form large nano-entities having distinct types and sizes and were capable of entering cells. The combination of strategies employed serves to detect and reveal nano-entities along with their three-state equilibria and behaviors in buffers, media, and cells.

Inhibition of HBsAg secretion by nucleic acid polymers in HepG2.2.15 cells.

More than 290 million people have chronic HBV infection and are at risk of developing cirrhosis and hepatocellular carcinoma. HBV subviral particles are produced in large excess over virions in infected patients and are the primary source of HBsAg, which is postulated to be important in allowing HBV to chronically persist by interfering with immune function. Nucleic acid polymers (NAPs) have been shown to result in clearance of HBsAg from the blood in pre-clinical and clinical studies.

LC3B is not recruited along with the autophagy elongation complex (ATG5-12/16L1) at HCV replication site and is dispensable for viral replication.

Hepatitis C virus (HCV) infection is known to induce autophagosome accumulation as observed by the typical punctate cytoplasmic distribution of LC3B-II in infected cells. Previously, we showed that viral RNA-dependent RNA polymerase (NS5B) interacts with ATG5, a major component of the autophagy elongation complex that is involved in the formation of double-membrane vesicles (DMV), and demonstrated that the autophagy elongation complex (ATG5-12/16L1) but not LC3B is required for proper membranous web formation. In this study, the colocalization and in situ interaction of all HCV replicase components with the constituent of the autophagy elongation complex and LC3B were analyzed.

The autophagy elongation complex (ATG5-12/16L1) positively regulates HCV replication and is required for wild-type membranous web formation.

Hepatitis C virus (HCV) infection induces intracellular membrane rearrangements, thus forming a membranous web (MW) in which HCV replication and assembly occur. The HCV-induced MW is primarily composed of double membrane vesicles (DMVs) transfused by multi-membrane vesicles. The autophagy machinery has been proposed to participate in the formation of such vesicles.

Statins can exert dual, concentration dependent effects on HCV entry in vitro.

Statins are used daily by a large and increasing number of individuals worldwide. They were initially designed as 3-hydroxy-3-methylglutharyl-coenzyme A reductase (HMG-CoAR) inhibitors to treat patients with hypercholesterolemia. Recent studies on HCV chronically infected individuals have suggested that their use in vivo in combination with PEG-IFN and ribavirin favor the sustained viral response (SVR).

Effect of the pituitary adenylate cyclase-activating polypeptide on the autophagic activation observed in in vitro and in vivo models of Parkinson's disease.

Parkinson's disease (PD) is a neurodegenerative disorder that leads to destruction of the midbrain dopaminergic (DA) neurons. This phenomenon is related to apoptosis and its activation can be blocked by the pituitary adenylate cyclase-activating polypeptide (PACAP). Growing evidence indicates that autophagy, a self-degradation activity that cleans up the cell, is induced during the course of neurodegenerative diseases.

Plasma Membrane Tetraspanin CD81 Complexes with Proprotein Convertase Subtilisin/Kexin Type 9 (PCSK9) and Low Density Lipoprotein Receptor (LDLR), and Its Levels Are Reduced by PCSK9.

Proprotein convertase subtilisin/kexin type 9 (PCSK9) is an important factor in plasma cholesterol regulation through modulation of low density lipoprotein receptor (LDLR) levels. Naturally occurring mutations can lead to hyper- or hypocholesterolemia in human. Recently, we reported that PCSK9 was also able to modulate CD81 in Huh7 cells.

SKI-1/S1P inhibitor PF-429242 impairs the onset of HCV infection.

Worldwide, approximately 170 million individuals are afflicted with chronic hepatitis C virus (HCV) infection. To prevent the development of inherent diseases such as cirrhosis and hepatocellular carcinoma, tremendous efforts have been made, leading to the development of promising new treatments. However, their efficiency is still dependent on the viral genotype.

Use of FDA approved therapeutics with hNTCP metabolic inhibitory properties to impair the HDV lifecycle.

Worldwide there are approximately 240million individuals chronically infected with the hepatitis B virus (HBV), including 15-20million coinfected with the hepatitis delta virus (HDV). Treatments available today are not fully efficient and often associated to important side effects and development of drug resistance. Targeting the HBV/HDV entry step using preS1-specific lipopeptides appears as a promising strategy to block viral entry for both HBV and HDV (Gripon et al.

Membrane fusion-mediated autophagy induction enhances morbillivirus cell-to-cell spread.

In the context of viral infections, autophagy induction can be beneficial or inhibitory. Within the Paramyxoviridae family, only morbilliviruses have been investigated and are reported to induce autophagy. Here we show that morbilliviruses rapidly induce autophagy and require this induction for efficient cell-to-cell spread.

SKI-1/S1P inhibition: a promising surrogate to statins to block hepatitis C virus replication.

Hepatitis C virus (HCV) is often associated with steatosis, cirrhosis and hepatocellular carcinoma (HCC). Statins (HMG-CoAR inhibitors) have been shown to exert an antiviral effect in vitro, principally on replicon harboring cells, but the effect of their use alone in vivo remains controversial. In clinical trials, when used in combination with the standards of care (SOC), they led to an increased proportion of sustained virological responder (SVR).

Autophagy protein ATG5 interacts transiently with the hepatitis C virus RNA polymerase (NS5B) early during infection.

Autophagy is an important cellular process by which ATG5 initiates the formation of double membrane vesicles (DMVs). Upon infection, DMVs have been shown to harbor the replicase complex of positive-strand RNA viruses such as MHV, poliovirus, and equine arteritis virus. Recently, it has been shown that autophagy proteins are proviral factors that favor initiation of hepatitis C virus (HCV) infection.

Novel HCV replication mouse model using human hepatocellular carcinoma xenografts.

In the absence of an immunocompetent mouse model for HCV replication, we developed a convenient xenograft mouse model that produces infectious viral particles. For this purpose, HCV-permissive tumors were generated in SCID/beige mice using a tumorigenic population of the human hepatocarcinoma-derived Huh7 cell line. Following infection, HCV RNA increased in the mouse sera and the human tumor by up to 10(5)GE/ml and 10(7)GE/microg of RNA, respectively.

PCSK9 impedes hepatitis C virus infection in vitro and modulates liver CD81 expression.

Unlabelled: Human PCSK9 is known to enhance the degradation of membrane-bound receptors such as the hepatocyte low-density lipoprotein receptor (LDLR), ApoER2, and very low-density lipoprotein receptor. Because the LDLR is suspected to be involved in hepatitis C virus (HCV) entry, we also tested whether PCSK9 can affect the levels of CD81, a major HCV receptor. Interestingly, stable expression of PCSK9 or a more active membrane-bound form of the protein (PCSK9-ACE2) resulted in a marked reduction in CD81 and LDLR expression.