We report the crystal structure of the RNA-dependent RNA polymerase of hepatitis C virus, a major human pathogen, to 2.8-Å resolution. This enzyme is a key target for developing specific antiviral therapy. The structure of the catalytic domain contains 531 residues folded in the characteristic fingers, palm, and thumb subdomains. The fingers subdomain contains a region, the ''fingertips,'' that shares the same fold with reverse transcriptases. Superposition to the available structures of the latter shows that residues from the palm and fingertips are structurally equivalent.
Neoantigens (nAgs) are promising tumor antigens for cancer vaccination with the potential of inducing robust and selective T cell responses. Genetic vaccines based on Adenoviruses derived from non-human Great Apes (GAd) elicit strong and effective T cell-mediated immunity in humans. Here, we investigate for the first time the potency and efficacy of a novel GAd encoding multiple neoantigens. Prophylactic or early therapeutic vaccination with GAd efficiently control tumor growth in mice. In contrast, combination of the vaccine with checkpoint inhibitors is required to eradicate large tumors. Gene expression profile of tumors in regression shows abundance of activated tumor infiltrating T cells with a more diversified TCR repertoire in animals treated with GAd and anti-PD1 compared to anti-PD1. Data suggest that effectiveness of vaccination in the presence of high tumor burden correlates with the breadth of nAgs-specific T cells and requires concomitant reversal of tumor suppression by checkpoint blockade.
The processing at the NS3/4A, NS4A/4B, NS4B/5A and NS5A/5B junctions in the non-structural region of the hepatitis C virus (HCV) polyprotein is performed by a viral serine protease activity contained within the N-terminal 180 amino acids of the NS3 protein. Full protease activity is only achieved upon the interaction of a region at the N terminus of NS3 with the NS4A protein, this region is also involved in the modulation of the protease activity. Using the rabbit reticulocyte expression system, we have defined the minimal domain of NS4A that is necessary to increase the cleavage efficiency of NS3. A synthetic peptide containing the same region, NS4A amino acids 21 to 32, stimulates the proteolytic activity of NS3 at all the trans-cleavage sites.
The RNA-dependent RNA polymerase activity of hepatitis C virus is carried out by the NS5B protein.The full-length protein was previously purified as a non-fusion protein from insect cells infected with a recombinant baculovirus. The characterization is now described of a C-terminal hydrophobic domain deletion mutant of NS5B purified from E. coli. In addition to increased solubility, deletion of this sequence also positively affected the polymerase enzymatic activity. The efficiency of nucleotide polymerization of both the full-length and the C-terminal truncated enzymes were compared on homopolymeric template-primer couples as well as on RNA templates with heteropolymeric sequences. The largest difference in the polymerase activity was observed on the latter. On all the templates, the increased activity could be ascribed, at least in part, to enhanced template turnover of the deletion mutant with respect to the full-length enzyme. The elongation rates of the two enzyme forms were compared under single processive cycle conditions. Under these conditions, both the full-length and the deletion mutant were able to incorporate about 700 nt/min.
Objective. To investigate the disease outcomes of a cross-sectional sample of children with longstanding juvenile idiopathic arthritis (JIA) seen between September 2002 and December 2006, and to provide a benchmarking of outcomes obtained with current treatment. Methods. All consecutive patients were included if they met the following criteria: diagnosis of JIA, disease duration >5 years, and informed consent. Outcome assessments included disease activity, inactive disease, minimal disease activity, pain, physical function, health-related quality of life (HRQOL), auxometric measurements, and articular and extraarticular damage. Results. A total of 310 patients were included. At study visit, patients had on average a low level of disease activity. However, only 21.8% met the criteria for inactive disease, and less than 50% met the definition of minimal disease activity. Additionally, 19.2% had moderate to severe Childhood Health Assessment Questionnaire disability and 3.6% were in Steinbrocker class III-IV. Approximately 10% had major impairment in HRQOL. A total of 34.2% had damage in >1 joint or joint group and 26.1% showed extraarticular damage. Of the 125 patients who underwent a wrist radiograph, 35.2% had significant structural damage and 8.7% had growth retardation. Conclusion. Our patients had on average a low level of disease activity, little or no physical disability, and a satisfactory HRQOL. However, a sizable proportion of patients had persistently active disease, impaired function, and damage. These findings underscore the critical need for treatments and treatment strategies that have the ability to better control disease activity and to reduce the development of disease-related morbidities.
Tumors with microsatellite instability (MSI) are caused by a defective DNA mismatch repair system that leads to the accumulation of mutations within microsatellite regions. Indels in microsatellites of coding genes can result in the synthesis of frameshift peptides (FSP). FSPs are tumor-specific neoantigens shared across patients with MSI. In this study, we developed a neoantigen-based vaccine for the treatment of MSI tumors. Genetic sequences from 320 MSI tumor biopsies and matched healthy tissues in The Cancer Genome Atlas database were analyzed to select shared FSPs. Two hundred nine FSPs were selected and cloned into nonhuman Great Ape Adenoviral and Modified Vaccinia Ankara vectors to generate a viral-vectored vaccine, referred to as Nous-209. Sequencing tumor biopsies of 20 independent patients with MSI colorectal cancer revealed that a median number of 31 FSPs out of the 209 encoded by the vaccine was detected both in DNA and mRNA extracted from each tumor biopsy. A relevant number of peptides encoded by the vaccine were predicted to bind patient HLA haplotypes. Vaccine immunogenicity was demonstrated in mice with potent and broad induction of FSP-specific CD8 and CD4 T-cell responses. Moreover, a vaccine-encoded FSP was processed in vitro by human antigen-presenting cells and was subsequently able to activate human CD8 T cells. Nous-209 is an "off-the-shelf" cancer vaccine encoding many neoantigens shared across sporadic and hereditary MSI tumors. These results indicate that Nous-209 can induce the optimal breadth of immune responses that might achieve clinical benefit to treat and prevent MSI tumors.Significance: These findings demonstrate the feasibility of an "off-the-shelf" vaccine for treatment and prevention of tumors harboring frameshift mutations and neoantigenic peptides as a result of microsatellite instability.
Heat shock proteins (Hsps) are induced by stressful stimuli and have been shown to protect cells and organs from such stresses both in vitro and in vivo, and play a positive role in lifespan determination. An attenuated response to stress is characteristic of senescence and no Hsp induction is observed upon exposure to stress and no protective effect of a mild stress is observed in cells from aged individuals. The artificial over-expression of Hsps, can produce a protective effect against a variety of damaging stimuli in cells from aged rats or aged humans, in whom cardiovascular disease is a major cause of morbidity in older age. Here, we show that aging significantly decreases the levels of Hsp27, Hsp60, Hsp72 and Hsc70 in right atrium and left ventricle of the rat heart, both at level of protein and of mRNA. Two different caloric restriction regimens have been found to counteract in part the decrease in the levels of Hsp expression in the aged heart tissue as well as the tendency to an increase of the levels of carbonyl in cardiac proteins. Our data suggest that cardiac Hsp levels may be a determinant of longevity in rodents, and that generation of new regimens of caloric restriction may eventually show how to improve modulation of cardiac aging.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.