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Journal of Clinical and Translational... May 2024After 3-years (144 week) of double-blind treatment in Chinese chronic hepatitis B patients in two ongoing phase 3 studies, tenofovir alafenamide (TAF) showed similar...
Five-year Treatment with Tenofovir Alafenamide Achieves High Rates of Viral Suppression, Alanine Aminotransferase Normalization, and Favorable Bone and Renal Safety in Chinese Chronic Hepatitis B Patients.
BACKGROUND AND AIMS
After 3-years (144 week) of double-blind treatment in Chinese chronic hepatitis B patients in two ongoing phase 3 studies, tenofovir alafenamide (TAF) showed similar efficacy to tenofovir disoproxil fumarate (TDF), with improved renal and bone safety. In this study, we aimed to report the 5-year results from 2 years into the open-label TAF treatment phase.
METHODS
All participants completing the 144-week double-blind treatment were eligible to receive open-label TAF 25 mg once daily up to week 384. Serial analysis of viral suppression (hepatitis B virus DNA <29 IU/mL), alanine aminotransferase normalization, serological responses, and safety outcomes at year 5 (week 240) was performed.
RESULTS
The open-label phase included 93% (311/334) of the enrolled participants, which included 212 who switched from double-blind TAF to open-label TAF (TAF-TAF) and 99 who switched from double-blind TDF to open-label TAF (TDF-TAF). Baseline characteristics were comparable. Week 240 viral suppression rates were similar between groups [93.4% vs. 93.9%; difference: -1.5%, (95% CI: -6.4 to -3.5), =0.857]. Alanine aminotransferase normalization and serological response rates were higher in the TAF-TAF group than in the TDF-TAF group. The frequencies of adverse events and laboratory abnormalities were low and similar between groups. Both groups had similar small numerical declines from baseline in estimated glomerular filtration rate at year 5 (week 240, -2.85 mL/min vs. -3.29 mL/min, =0.910). The greater declines in renal and bone parameters in the TDF-TAF group through week 144 improved after switching to TAF.
CONCLUSIONS
The 5-year TAF treatment efficacy was high and similar to that of 3-year TDF followed by 2-year TAF in Chinese chronic hepatitis B patients. Favorable effects on bone and renal parameters were sustained with TAF treatment alone and were observed following the switch from TDF to TAF.
PubMed: 38779514
DOI: 10.14218/JCTH.2023.00417 -
Virus Research Aug 2024The gut of healthy neonates is devoid of viruses at birth, but rapidly becomes colonised by normal viral commensals that aid in important physiological functions like...
The gut of healthy neonates is devoid of viruses at birth, but rapidly becomes colonised by normal viral commensals that aid in important physiological functions like metabolism but can, in some instances, result in gastrointestinal illnesses. However, little is known about how this colonisation begins, its variability and factors shaping the gut virome composition. Thus, understanding the development, assembly, and progression of enteric viral communities over time is key. To explore early-life virome development, metagenomic sequencing was employed in faecal samples collected longitudinally from a cohort of 17 infants during their first six months of life. The gut virome analysis revealed a diverse and dynamic viral community, formed by a richness of different viruses infecting humans, non-human mammals, bacteria, and plants. Eukaryotic viruses were detected as early as one week of life, increasing in abundance and diversity over time. Most of the viruses detected are commonly associated with gastroenteritis and include members of the Caliciviridae, Picornaviridae, Astroviridae, Adenoviridae, and Sedoreoviridae families. The most common co-occurrences involved asymptomatic norovirus-parechovirus, norovirus-sapovirus, sapovirus-parechovirus, observed in at least 40 % of the samples. Majority of the plant-derived viruses detected in the infants' gut were from the Virgaviridae family. This study demonstrates the first longitudinal characterisation of the gastrointestinal virome in infants, from birth up to 6 months of age, in sub-Saharan Africa. Overall, the findings from this study delineate the composition and variability of the healthy infants' gut virome over time, which is a significant step towards understanding the dynamics and biogeography of viral communities in the infant gut.
Topics: Humans; Virome; South Africa; Infant; Longitudinal Studies; Feces; Infant, Newborn; Gastrointestinal Microbiome; Male; Female; Viruses; Metagenomics; Gastrointestinal Tract; Gastroenteritis; Sapovirus; Norovirus; Picornaviridae; Caliciviridae; Metagenome
PubMed: 38776984
DOI: 10.1016/j.virusres.2024.199403 -
The Journal of General Virology May 2024Porcine reproductive and respiratory syndrome (PRRSV) is an enveloped single-stranded positive-sense RNA virus and one of the main pathogens that causes the most...
Porcine reproductive and respiratory syndrome (PRRSV) is an enveloped single-stranded positive-sense RNA virus and one of the main pathogens that causes the most significant economical losses in the swine-producing countries. PRRSV is currently divided into two distinct species, PRRSV-1 and PRRSV-2. The PRRSV virion envelope is composed of four glycosylated membrane proteins and three non-glycosylated envelope proteins. Previous work has suggested that PRRSV-linked glycans are critical structural components for virus assembly. In addition, it has been proposed that PRRSV glycans are implicated in the interaction with host cells and critical for virus infection. In contrast, recent findings showed that removal of N-glycans from PRRSV does not influence virus infection of permissive cells. Thus, there are not sufficient evidences to indicate compellingly that N-glycans present in the PRRSV envelope play a direct function in viral infection. To gain insights into the role of N-glycosylation in PRRSV infection, we analysed the specific contribution of the envelope protein-linked N-glycans to infection of permissive cells. For this purpose, we used a novel strategy to modify envelope protein-linked N-glycans that consists of production of monoglycosylated PRRSV and viral glycoproteins with different glycan states. Our results showed that removal or alteration of N-glycans from PRRSV affected virus infection. Specifically, we found that complex N-glycans are required for an efficient infection in cell cultures. Furthermore, we found that presence of high mannose type glycans on PRRSV surface is the minimal requirement for a productive viral infection. Our findings also show that PRRSV-1 and PRRSV-2 have different requirements of N-glycan structure for an optimal infection. In addition, we demonstrated that removal of N-glycans from PRRSV does not affect viral attachment, suggesting that these carbohydrates played a major role in regulating viral entry. In agreement with these findings, by performing immunoprecipitation assays and colocalization experiments, we found that N-glycans present in the viral envelope glycoproteins are not required to bind to the essential viral receptor CD163. Finally, we found that the presence of N-glycans in CD163 is not required for PRRSV infection.
Topics: Porcine respiratory and reproductive syndrome virus; Glycosylation; Animals; Swine; Polysaccharides; Porcine Reproductive and Respiratory Syndrome; Viral Envelope Proteins; Cell Line; Receptors, Cell Surface; Antigens, Differentiation, Myelomonocytic; Antigens, CD; Viral Envelope
PubMed: 38776134
DOI: 10.1099/jgv.0.001994 -
Veterinary Research May 2024The maintenance of viral protein homeostasis depends on the interaction between host cell proteins and viral proteins. As a molecular chaperone, heat shock protein 70...
HSP70 positively regulates translation by interacting with the IRES and stabilizes the viral structural proteins VP1 and VP3 to facilitate duck hepatitis A virus type 1 replication.
The maintenance of viral protein homeostasis depends on the interaction between host cell proteins and viral proteins. As a molecular chaperone, heat shock protein 70 (HSP70) has been shown to play an important role in viral infection. Our results showed that HSP70 can affect translation, replication, assembly, and release during the life cycle of duck hepatitis A virus type 1 (DHAV-1). We demonstrated that HSP70 can regulate viral translation by interacting with the DHAV-1 internal ribosome entry site (IRES). In addition, HSP70 interacts with the viral capsid proteins VP1 and VP3 and promotes their stability by inhibiting proteasomal degradation, thereby facilitating the assembly of DHAV-1 virions. This study demonstrates the specific role of HSP70 in regulating DHAV-1 replication, which are helpful for understanding the pathogenesis of DHAV-1 infection and provide additional information about the role of HSP70 in infection by different kinds of picornaviruses, as well as the interaction between picornaviruses and host cells.
Topics: Hepatitis Virus, Duck; HSP70 Heat-Shock Proteins; Virus Replication; Animals; Internal Ribosome Entry Sites; Viral Structural Proteins; Ducks; Poultry Diseases; Picornaviridae Infections; Capsid Proteins; Hepatitis, Viral, Animal; Protein Biosynthesis
PubMed: 38760810
DOI: 10.1186/s13567-024-01315-9 -
Liver Cancer Jun 2024Intratumoral administration of pexa-vec (pexastimogene devacirepvec), an oncolytic and immunotherapeutic vaccinia virus, given to patients with hepatocellular carcinoma...
INTRODUCTION
Intratumoral administration of pexa-vec (pexastimogene devacirepvec), an oncolytic and immunotherapeutic vaccinia virus, given to patients with hepatocellular carcinoma (HCC), is associated with both local and distant tumor responses. We hypothesized subsequent treatment with sorafenib could demonstrate superior efficacy.
METHODS
This random phase III open-label study evaluated the sequential treatment with pexa-vec followed by sorafenib compared to sorafenib in patients with advanced HCC and no prior systemic treatment. The primary endpoint is overall survival (OS). Key secondary endpoints included time to progression (TTP), progression-free survival, overall response rate (ORR), and disease control rate (DCR). Safety was assessed in all patients who received ≥1 dose of study treatment.
RESULTS
The study was conducted at 142 sites in 16 countries. From December 30, 2015, to the interim analysis on August 2, 2019, 459 patients were randomly assigned (pexa-vec plus sorafenib: 234, sorafenib: 225). At the interim analysis, the median OS was 12.7 months (95% CI: 9.89, 14.95) in the pexa-vec plus sorafenib arm and 14.0 months (95% CI: 11.01, 18.00) in the sorafenib arm. This led to the early termination of the study. The median TTP was 2.0 months (95% CI: 1.77, 2.96) and 4.2 months (95% CI: 2.92, 4.63); ORR was 19.2% (45 patients) and 20.9% (47 patients); and DCR was 50.0% (117 patients) and 57.3% (129 patients) in the pexa-vec plus sorafenib and sorafenib arms, respectively. Serious adverse events were reported in 117 (53.7%) patients in the pexa-vec plus sorafenib and 77 (35.5%) patients in the sorafenib arm. Liver failure was the most frequently reported in both groups.
CONCLUSION
Sequential pexa-vec plus sorafenib treatment did not demonstrate increased clinical benefit in advanced HCC and fared worse compared to sorafenib alone. The advent of the added value of checkpoint inhibitors should direct any further development of oncolytic virus therapy strategies.
PubMed: 38756145
DOI: 10.1159/000533650 -
Communications Biology May 2024Infection of bacteria by phages is a complex multi-step process that includes specific recognition of the host cell, creation of a temporary breach in the host envelope,...
Infection of bacteria by phages is a complex multi-step process that includes specific recognition of the host cell, creation of a temporary breach in the host envelope, and ejection of viral DNA into the bacterial cytoplasm. These steps must be perfectly regulated to ensure efficient infection. Here we report the dual function of the tail completion protein gp16.1 of bacteriophage SPP1. First, gp16.1 has an auxiliary role in assembly of the tail interface that binds to the capsid connector. Second, gp16.1 is necessary to ensure correct routing of phage DNA to the bacterial cytoplasm. Viral particles assembled without gp16.1 are indistinguishable from wild-type virions and eject DNA normally in vitro. However, they release their DNA to the extracellular space upon interaction with the host bacterium. The study shows that a highly conserved tail completion protein has distinct functions at two essential steps of the virus life cycle in long-tailed phages.
Topics: Viral Tail Proteins; Bacteriophages; DNA, Viral; Virion
PubMed: 38755280
DOI: 10.1038/s42003-024-06221-6 -
Nature Communications May 2024The multibasic furin cleavage site at the S1/S2 boundary of the spike protein is a hallmark of SARS-CoV-2 and plays a crucial role in viral infection. However, the...
The multibasic furin cleavage site at the S1/S2 boundary of the spike protein is a hallmark of SARS-CoV-2 and plays a crucial role in viral infection. However, the mechanism underlying furin activation and its regulation remain poorly understood. Here, we show that GalNAc-T3 and T7 jointly initiate clustered O-glycosylations in the furin cleavage site of the SARS-CoV-2 spike protein, which inhibit furin processing, suppress the incorporation of the spike protein into virus-like-particles and affect viral infection. Mechanistic analysis reveals that the assembly of the spike protein into virus-like particles relies on interactions between the furin-cleaved spike protein and the membrane protein of SARS-CoV-2, suggesting a possible mechanism for furin activation. Interestingly, mutations in the spike protein of the alpha and delta variants of the virus confer resistance against glycosylation by GalNAc-T3 and T7. In the omicron variant, additional mutations reverse this resistance, making the spike protein susceptible to glycosylation in vitro and sensitive to GalNAc-T3 and T7 expression in human lung cells. Our findings highlight the role of glycosylation as a defense mechanism employed by host cells against SARS-CoV-2 and shed light on the evolutionary interplay between the host and the virus.
Topics: Spike Glycoprotein, Coronavirus; Humans; SARS-CoV-2; Glycosylation; Furin; COVID-19; Mutation; HEK293 Cells; N-Acetylgalactosaminyltransferases; Animals; Chlorocebus aethiops; Polypeptide N-acetylgalactosaminyltransferase
PubMed: 38755139
DOI: 10.1038/s41467-024-48503-x -
The Journal of Biological Chemistry Jun 2024The main protease (M) remains an essential therapeutic target for COVID-19 post infection intervention given its critical role in processing the majority of viral...
The main protease (M) remains an essential therapeutic target for COVID-19 post infection intervention given its critical role in processing the majority of viral proteins encoded by the genome of severe acute respiratory syndrome related coronavirus 2 (SARS-CoV-2). Upon viral entry, the +ssRNA genome is translated into two long polyproteins (pp1a or the frameshift-dependent pp1ab) containing all the nonstructural proteins (nsps) required by the virus for immune modulation, replication, and ultimately, virion assembly. Included among these nsps is the cysteine protease M (nsp5) which self-excises from the polyprotein, dimerizes, then sequentially cleaves 11 of the 15 cut-site junctions found between each nsp within the polyprotein. Many structures of M (often bound to various small molecule inhibitors or peptides) have been detailed recently, including structures of M bound to each of the polyprotein cleavage sequences, showing that M can accommodate a wide range of targets within its active site. However, to date, kinetic characterization of the interaction of M with each of its native cleavage sequences remains incomplete. Here, we present a robust and cost-effective FRET based system that benefits from a more consistent presentation of the substrate that is also closer in organization to the native polyprotein environment compared to previously reported FRET systems that use chemically modified peptides. Using this system, we were able to show that while each site maintains a similar Michaelis constant, the catalytic efficiency of M varies greatly between cut-site sequences, suggesting a clear preference for the order of nsp processing.
Topics: SARS-CoV-2; Fluorescence Resonance Energy Transfer; Polyproteins; Kinetics; Coronavirus 3C Proteases; Humans; COVID-19; Viral Proteins; Proteolysis
PubMed: 38750796
DOI: 10.1016/j.jbc.2024.107367 -
Structure (London, England : 1993) May 2024Orthomyxoviruses, such as influenza and thogotoviruses, are important human and animal pathogens. Their segmented viral RNA genomes are wrapped by viral nucleoproteins...
Orthomyxoviruses, such as influenza and thogotoviruses, are important human and animal pathogens. Their segmented viral RNA genomes are wrapped by viral nucleoproteins (NPs) into helical ribonucleoprotein complexes (RNPs). NP structures of several influenza viruses have been reported. However, there are still contradictory models of how orthomyxovirus RNPs are assembled. Here, we characterize the crystal structure of Thogoto virus (THOV) NP and found striking similarities to structures of influenza viral NPs, including a two-lobed domain architecture, a positively charged RNA-binding cleft, and a tail loop important for trimerization and viral transcription. A low-resolution cryo-electron tomography reconstruction of THOV RNPs elucidates a left-handed double helical assembly. By providing a model for RNP assembly of THOV, our study suggests conserved NP assembly and RNA encapsidation modes for thogoto- and influenza viruses.
PubMed: 38749445
DOI: 10.1016/j.str.2024.04.016 -
BioRxiv : the Preprint Server For... May 2024Viral infection induces production of type I interferons and expression of interferon-stimulated genes (ISGs) that play key roles in inhibiting viral infection. Here, we...
Interferon-Inducible Guanylate-Binding Protein 5 Inhibits Replication of Multiple Viruses by Binding to the Oligosaccharyltransferase Complex and Inhibiting Glycoprotein Maturation.
Viral infection induces production of type I interferons and expression of interferon-stimulated genes (ISGs) that play key roles in inhibiting viral infection. Here, we show that the ISG guanylate-binding protein 5 (GBP5) inhibits N-linked glycosylation of key proteins in multiple viruses, including SARS-CoV-2 spike protein. GBP5 binds to accessory subunits of the host oligosaccharyltransferase (OST) complex and blocks its interaction with the spike protein, which results in misfolding and retention of spike protein in the endoplasmic reticulum likely due to decreased -glycan transfer, and reduces the assembly and release of infectious virions. Consistent with these observations, pharmacological inhibition of the OST complex with NGI-1 potently inhibits glycosylation of other viral proteins, including MERS-CoV spike protein, HIV-1 gp160, and IAV hemagglutinin, and prevents the production of infectious virions. Our results identify a novel strategy by which ISGs restrict virus infection and provide a rationale for targeting glycosylation as a broad antiviral therapeutic strategy.
PubMed: 38746287
DOI: 10.1101/2024.05.01.591800