RESUMEN
BACKGROUND: Real-world evidence to support optimal ustekinumab dosing for refractory Crohn's disease (CD) patients remains limited. Data from a retrospective nationwide chart review study was utilized to explore ustekinumab dosing dynamics and optimization, identify possible clinical predictors of dose intensification, and to evaluate ustekinumab trough concentrations (TCs) and concomitant medication use in Finland. METHODS: Information gathered from17 Finnish hospitals included clinical chart data from 155 adult CD patients who received intravenous ustekinumab induction during 2017-2018. Data on ustekinumab dosing and TCs, concomitant corticosteroid and immunosuppressant use, and antiustekinumab antibodies were analyzed in a two-year follow-up, subject to availability. RESULTS: Among 140 patients onustekinumab maintenance therapy, dose optimization was required in 55(39%) of the patients, and 41/47 dose-intensified patients (87%) persisted on ustekinumab. At baseline, dose-intensified patient group had significantly higher C-reactive protein (CRP) levels, and at week 16, significantly lower ustekinumab TCs than in patients without dose intensification. Irrespective of dose optimization, a statistically significant reduction in the use of corticosteroids was observed at both 16 weeks and one year, coupled with an increased proportion of patients on ustekinumab monotherapy. Antiustekinumab antibodies were undetectable in all 28 samples from 25 patients collected throughout the study period. CONCLUSIONS: Nearly a third of all CD patients on ustekinumab maintenance therapy, with a history of treatment-refractory and long-standing disease, required dose intensification. These patients persisted on ustekinumab and had significant reduction of corticosteroid use. Increased baseline CRP was identified as the sole indicator of dose intensification. TRIAL REGISTRATION: EUPAS30920.
Asunto(s)
Enfermedad de Crohn , Ustekinumab , Corticoesteroides , Adulto , Enfermedad de Crohn/tratamiento farmacológico , Finlandia , Humanos , Inducción de Remisión , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
OBJECTIVE: Long-term evidence on ustekinumab treatment response and persistence in patients with Crohn's disease in a real-world setting is scarce. We performed a retrospective nationwide chart review study of long-term clinical outcomes in Crohn's disease patients treated with ustekinumab. METHODS: The study was conducted in 17 Finnish hospitals and included adult Crohn's disease patients who received an initial intravenous dose of ustekinumab during 2017-2018. Disease activity data were collected at baseline, 16 weeks, and 1 year from health records. RESULTS: The study included 155 patients. The disease was stricturing or penetrating in 69 and 59% had prior Crohn's disease-related surgeries, and 97% had a treatment history of at least one biologic agent. Of 93 patients with ≥1 year of follow-up, 77 (83%) were still on ustekinumab at 1 year. In patients with data available, from baseline to the 1-year follow-up the simple endoscopic score for Crohn's disease (SES-CD) decreased from 10 to 3 (P = 0.033), C-reactive protein from 7 to 5 mg/L, (P < 0.001) and faecal calprotectin from 776 to 305 µg/g (P < 0.001). CONCLUSIONS: Ustekinumab treatment in patients with highly refractory Crohn's disease resulted in high long-term treatment persistence and significantly reduced disease activity, assessed with objective markers for intestinal inflammatory activity.
Asunto(s)
Enfermedad de Crohn , Preparaciones Farmacéuticas , Adulto , Enfermedad de Crohn/diagnóstico , Enfermedad de Crohn/tratamiento farmacológico , Finlandia/epidemiología , Humanos , Inducción de Remisión , Estudios Retrospectivos , Ustekinumab/efectos adversosRESUMEN
AIMS/HYPOTHESIS: Enterovirus infections have been implicated in the aetiology of autoimmune type 1 diabetes. A vaccine could be used to test the causal relationship between enterovirus infections and diabetes development. However, the development of a vaccine against a virus suspected to induce an autoimmune disease is challenging, since the vaccine itself might trigger autoimmunity. Another challenge is to select the enterovirus serotypes to target with a vaccine. Here we aimed to evaluate the function and autoimmune safety of a novel non-adjuvanted prototype vaccine to Coxsackievirus serotype B1 (CVB1), a member of the enterovirus genus. METHODS: A formalin-inactivated CVB1 vaccine was developed and tested for its immunogenicity and safety in BALB/c and NOD mice. Prediabetic NOD mice were vaccinated, infected with CVB1 or mock-treated to compare the effect on diabetes development. RESULTS: Vaccinated mice produced high titres of CVB1-neutralising antibodies without signs of vaccine-related side effects. Vaccinated mice challenged with CVB1 had significantly reduced levels of replicating virus in their blood and the pancreas. Prediabetic NOD mice demonstrated an accelerated onset of diabetes upon CVB1 infection whereas no accelerated disease manifestation or increased production of insulin autoantibodies was observed in vaccinated mice. CONCLUSIONS/INTERPRETATION: We conclude that the prototype vaccine is safe and confers protection from infection without accelerating diabetes development in mice. These results encourage the development of a multivalent enterovirus vaccine for human use, which could be used to determine whether enterovirus infections trigger beta cell autoimmunity and type 1 diabetes in humans.
Asunto(s)
Anticuerpos Antivirales/metabolismo , Infecciones por Coxsackievirus/patología , Diabetes Mellitus Experimental/metabolismo , Infecciones por Enterovirus/patología , Vacunas Virales/farmacología , Animales , Modelos Animales de Enfermedad , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos NODRESUMEN
Coxsackievirus B3 (CVB3) is an important cause of acute and chronic viral myocarditis, and dilated cardiomyopathy (DCM). Although vaccination against CVB3 could significantly reduce the incidence of serious or fatal viral myocarditis and various other diseases associated with CVB3 infection, there is currently no vaccine or therapeutic reagent in clinical use. In this study, we contributed towards the development of a CVB3 vaccine by establishing an efficient and scalable ion exchange chromatography-based purification method for CVB3 virus and baculovirus-insect cell-expressed CVB3 virus-like particles (VLPs). This purification system is especially relevant for vaccine development and production on an industrial scale. The produced VLPs were characterized using a number of biophysical methods and exhibited excellent quality and high purity. Immunization of mice with VLPs elicited a strong immune response, demonstrating the excellent vaccine potential of these VLPs.
Asunto(s)
Infecciones por Coxsackievirus/inmunología , Enterovirus Humano B/inmunología , Vacunas de Partículas Similares a Virus/inmunología , Animales , Anticuerpos Antivirales/inmunología , Especificidad de Anticuerpos , Baculoviridae/genética , Cromatografía por Intercambio Iónico , Infecciones por Coxsackievirus/prevención & control , Modelos Animales de Enfermedad , Femenino , Orden Génico , Vectores Genéticos/genética , Inmunidad Celular , Inmunización , Ratones , Vacunas de Partículas Similares a Virus/aislamiento & purificación , Vacunas de Partículas Similares a Virus/ultraestructuraRESUMEN
The RNA-dependent RNA polymerase (RdRP) of double-stranded RNA (dsRNA) viruses performs both RNA replication and transcription. In order to initiate RNA polymerization, viral RdRPs must be able to interact with the incoming 3' terminus of the template and position it, so that a productive binary complex is formed. Structural studies have revealed that RdRPs of dsRNA viruses that lack helicases have electrostatically charged areas on the polymerase surface, which might facilitate such interactions. In this study, structure-based mutagenesis, enzymatic assays and molecular mapping of bacteriophage phi 6 RdRP and its RNA were used to elucidate the roles of the negatively charged plough area on the polymerase surface, of the rim of the template tunnel and of the template specificity pocket that is key in the formation of the productive RNA-polymerase binary complex. The positively charged rim of the template tunnel has a significant role in the engagement of highly structured ssRNA molecules, whereas specific interactions further down in the template tunnel promote ssRNA entry to the catalytic site. Hence, we show that by aiding the formation of a stable binary complex with optimized RNA templates, the overall polymerization activity of the phi 6 RdRP can be greatly enhanced.
Asunto(s)
Bacteriófago phi 6/enzimología , ARN Polimerasa Dependiente del ARN/metabolismo , ARN/biosíntesis , Proteínas Virales/metabolismo , Secuencia de Aminoácidos , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , ARN/química , ARN/metabolismo , ARN Polimerasa Dependiente del ARN/genética , Moldes Genéticos , Proteínas Virales/genéticaRESUMEN
The biological role of manganese (Mn(2+)) has been a long-standing puzzle, since at low concentrations it activates several polymerases whilst at higher concentrations it inhibits. Viral RNA polymerases possess a common architecture, reminiscent of a closed right hand. The RNA-dependent RNA polymerase (RdRp) of bacteriophage 6 is one of the best understood examples of this important class of polymerases. We have probed the role of Mn(2+) by biochemical, biophysical and structural analyses of the wild-type enzyme and of a mutant form with an altered Mn(2+)-binding site (E491 to Q). The E491Q mutant has much reduced affinity for Mn(2+), reduced RNA binding and a compromised elongation rate. Loss of Mn(2+) binding structurally stabilizes the enzyme. These data and a re-examination of the structures of other viral RNA polymerases clarify the role of manganese in the activation of polymerization: Mn(2+) coordination of a catalytic aspartate is necessary to allow the active site to properly engage with the triphosphates of the incoming NTPs. The structural flexibility caused by Mn(2+) is also important for the enzyme dynamics, explaining the requirement for manganese throughout RNA polymerization.
Asunto(s)
Bacteriófago phi 6/enzimología , Manganeso/química , ARN Polimerasa Dependiente del ARN/química , Proteínas Virales/química , Sitios de Unión , Guanosina Trifosfato/química , Modelos Moleculares , Mutación , ARN/biosíntesis , ARN Polimerasa Dependiente del ARN/genética , ARN Polimerasa Dependiente del ARN/metabolismo , Moldes Genéticos , Proteínas Virales/genética , Proteínas Virales/metabolismoRESUMEN
The replication and transcription of double-stranded RNA (dsRNA) viruses occur within a polymerase complex particle in which the viral genome is enclosed throughout the entire life cycle of the virus. A single protein subunit in the polymerase complex is responsible for the template-dependent RNA polymerization activity. The isolated polymerase subunit of the dsRNA bacteriophage phi6 was previously shown to replicate and transcribe given RNA molecules. In this study, we show that this enzyme also catalyzes nontemplated nucleotide additions to single-stranded and double-stranded nucleic acid molecules. This terminal nucleotidyltransferase activity not only is a property of the isolated enzyme but also is detected to take place within the viral nucleocapsid. This is the first time terminal nucleotidyltransferase activity has been reported for a dsRNA virus as well as for a viral particle. The results obtained together with previous high-resolution structural data on the phi6 RNA-dependent RNA polymerase suggest a mechanism for terminal nucleotidyl addition. We propose that the activity is involved in the termination of the template-dependent RNA polymerization reaction on the linear phi6 genome.
Asunto(s)
Bacteriófago phi 6/enzimología , Nucleótidos/metabolismo , Nucleotidiltransferasas/metabolismo , ARN Bicatenario/metabolismo , ARN Polimerasa Dependiente del ARN/metabolismo , Bacteriófago phi 6/genética , Secuencia de Bases , Modelos Biológicos , Datos de Secuencia Molecular , Nucleocápside/metabolismo , Plásmidos , ARN Bicatenario/genética , ARN Viral/genética , ARN Viral/metabolismo , ARN Polimerasa Dependiente del ARN/genética , Moldes GenéticosRESUMEN
RNA silencing refers to a group of RNA-induced gene-silencing mechanisms that developed early in the eukaryotic lineage, probably for defence against pathogens and regulation of gene expression. In plants, protozoa, fungi, and nematodes, but apparently not insects and vertebrates, it involves a cell-encoded RNA-dependent RNA polymerase (cRdRP) that produces double-stranded RNA triggers from aberrant single-stranded RNA. We report the 2.3-A resolution crystal structure of QDE-1, a cRdRP from Neurospora crassa, and find that it forms a relatively compact dimeric molecule, each subunit of which comprises several domains with, at its core, a catalytic apparatus and protein fold strikingly similar to the catalytic core of the DNA-dependent RNA polymerases responsible for transcription. This evolutionary link between the two enzyme types suggests that aspects of RNA silencing in some organisms may recapitulate transcription/replication pathways functioning in the ancient RNA-based world.