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1.
Rep Prog Phys ; 83(12): 124201, 2020 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-33226008

RESUMO

The combination of the high intensity proton beam facilities and massive detectors for precision measurements of neutrino oscillation parameters including the charge-parity violating (CPV) phase will open the door to help make beyond the standard model (BSM) physics reachable even in low energy regimes in the accelerator-based experiments. Large-mass detectors with highly precise tracking and energy measurements, excellent timing resolution, and low energy thresholds will enable the searches for BSM phenomena from cosmogenic origin, as well. Therefore, it is also conceivable that BSM topics in the next-generation neutrino experiments could be the dominant physics topics in the foreseeable future, as the precision of the neutrino oscillation parameter and CPV measurements continue to improve.This paper provides a review of the current landscape of BSM theory in neutrino experiments in two selected areas of the BSM topics-dark matter and neutrino related BSM-and summarizes the current results from existing neutrino experiments to set benchmarks for both theory and experiment. This paper then provides a review of upcoming neutrino experiments throughout the next 10 to 15 year time scale and their capabilities to set the foundation for potential reach in BSM physics in the two aforementioned themes. An important outcome of this paper is to ensure theoretical and simulation tools exist to carry out studies of these new areas of physics, from the first day of the experiments, such as Deep Underground Neutrino Experiment in the U.S. and Hyper-Kamiokande Experiment in Japan.

2.
Invest New Drugs ; 38(3): 844-854, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-31385109

RESUMO

Background Endothelin B receptor (ETBR) is involved in melanoma pathogenesis and is overexpressed in metastatic melanoma. The antibody-drug conjugate DEDN6526A targets ETBR and is comprised of the humanized anti-ETBR monoclonal antibody conjugated to the anti-mitotic agent monomethyl auristatin E (MMAE). Methods This Phase I study evaluated the safety, pharmacokinetics, pharmacodynamics, and anti-tumor activity of DEDN6526A (0.3-2.8 mg/kg) given every 3 weeks (q3w) in patients with metastatic or unresectable cutaneous, mucosal, or uveal melanoma. Results Fifty-three patients received a median of 6 doses of DEDN6526A (range 1-49). The most common drug-related adverse events (>25% across dose levels) were fatigue, peripheral neuropathy, nausea, diarrhea, alopecia, and chills. Three patients in dose-escalation experienced a dose-limiting toxicity (infusion-related reaction, increased ALT/AST, and drug-induced liver injury). Based on cumulative safety data across all dose levels, the recommended Phase II dose (RP2D) for DEDN6526A was 2.4 mg/kg intravenous (IV) q3w. The pharmacokinetics of antibody-conjugated MMAE and total antibody were dose-proportional at doses ranging from 1.8-2.8 mg/kg. A trend toward faster clearance was observed at doses of 0.3-1.2 mg/kg. There were 6 partial responses (11%) in patients with metastatic cutaneous or mucosal melanoma, and 17 patients (32%) had prolonged stable disease ≥6 months. Responses were independent of BRAF mutation status but did correlate with ETBR expression. Conclusion DEDN6526A administered at the RP2D of 2.4 mg/kg q3w had an acceptable safety profile and showed evidence of anti-tumor activity in patients with cutaneous, mucosal, and uveal melanoma. ClinicalTrials.gov identifier: NCT01522664.


Assuntos
Anticorpos Monoclonais/uso terapêutico , Antagonistas do Receptor de Endotelina B/uso terapêutico , Imunoconjugados/uso terapêutico , Melanoma/tratamento farmacológico , Receptor de Endotelina B/metabolismo , Neoplasias Uveais/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Esquema de Medicação , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem
3.
Phys Rev Lett ; 125(7): 071801, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32857527

RESUMO

Searches for electron antineutrino, muon neutrino, and muon antineutrino disappearance driven by sterile neutrino mixing have been carried out by the Daya Bay and MINOS+ collaborations. This Letter presents the combined results of these searches, along with exclusion results from the Bugey-3 reactor experiment, framed in a minimally extended four-neutrino scenario. Significantly improved constraints on the θ_{µe} mixing angle are derived that constitute the most constraining limits to date over five orders of magnitude in the mass-squared splitting Δm_{41}^{2}, excluding the 90% C.L. sterile-neutrino parameter space allowed by the LSND and MiniBooNE observations at 90% CL_{s} for Δm_{41}^{2}<13 eV^{2}. Furthermore, the LSND and MiniBooNE 99% C.L. allowed regions are excluded at 99% CL_{s} for Δm_{41}^{2}<1.6 eV^{2}.

4.
Phys Rev Lett ; 125(13): 131802, 2020 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-33034464

RESUMO

We report the final measurement of the neutrino oscillation parameters Δm_{32}^{2} and sin^{2}θ_{23} using all data from the MINOS and MINOS+ experiments. These data were collected using a total exposure of 23.76×10^{20} protons on target producing ν_{µ} and ν[over ¯]_{µ} beams and 60.75 kt yr exposure to atmospheric neutrinos. The measurement of the disappearance of ν_{µ} and the appearance of ν_{e} events between the Near and Far detectors yields |Δm_{32}^{2}|=2.40_{-0.09}^{+0.08}(2.45_{-0.08}^{+0.07})×10^{-3} eV^{2} and sin^{2}θ_{23}=0.43_{-0.04}^{+0.20}(0.42_{-0.03}^{+0.07}) at 68% C.L. for normal (inverted) hierarchy.

5.
Phys Rev Lett ; 122(9): 091803, 2019 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-30932529

RESUMO

A search for mixing between active neutrinos and light sterile neutrinos has been performed by looking for muon neutrino disappearance in two detectors at baselines of 1.04 and 735 km, using a combined MINOS and MINOS+ exposure of 16.36×10^{20} protons on target. A simultaneous fit to the charged-current muon neutrino and neutral-current neutrino energy spectra in the two detectors yields no evidence for sterile neutrino mixing using a 3+1 model. The most stringent limit to date is set on the mixing parameter sin^{2}θ_{24} for most values of the sterile neutrino mass splitting Δm_{41}^{2}>10^{-4} eV^{2}.

6.
Osteoarthritis Cartilage ; 25(2): 249-258, 2017 02.
Artigo em Inglês | MEDLINE | ID: mdl-27666512

RESUMO

OBJECTIVE: To estimate and project the productivity costs of work loss (PCWL) associated with osteoarthritis (OA) in Canada using the Population Health Model (POHEM). DESIGN: We integrated an employment module based on 2006 Canadian Census into the previously developed microsimulation model of OA. The Canadian Community Health Survey (CCHS) Cycle 2.1 with an OA sample aged 25-64 (n = 7067) was used to calibrate the results of the employment module and to estimate the fraction of non-employment associated with OA. Probabilities of non-employment together with attributable fractions were then implemented in POHEM to estimate PCWL associated with OA from 2010 to 2031. RESULTS: Among the OA population, 44.4% and 59.4% of non-employment due to illness was associated with OA for those not working full-year and part-year, respectively. According to POHEM projections, the size of the working age population with OA increased from 1.5 million in 2010 to 1.7 million in 2031. The PCWL associated with OA increased from $12 billion to $17.5 billion in constant 2008 Canadian dollars. Around 38% of this increase was due to the increase in OA prevalence and changes in demographics, while the rest was due to increase in real wage growth. Male and female OA patients between 55 and 64 years of age had the highest total projected PCWL, respectively. CONCLUSIONS: The total PCWL associated with OA in Canada is estimated to be substantial and increasing in future years. Results of this study could be used to inform policies aiming to increase employment sustainability among individuals with OA.


Assuntos
Efeitos Psicossociais da Doença , Osteoartrite/epidemiologia , Desemprego/tendências , Adulto , Canadá/epidemiologia , Pessoas com Deficiência/estatística & dados numéricos , Feminino , Previsões , Humanos , Incidência , Masculino , Pessoa de Meia-Idade , Osteoartrite/economia , Prevalência , Licença Médica/economia , Licença Médica/estatística & dados numéricos , Licença Médica/tendências , Desemprego/estatística & dados numéricos
7.
Curr Oncol ; 24(6): 401-406, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29270052

RESUMO

The Canadian Partnership Against Cancer was created in 2007 by the federal government to accelerate cancer control across Canada. Its OncoSim microsimulation model platform, which consists of a suite of specific cancer models, was conceived as a tool to augment conventional resources for population-level policy- and decision-making. The Canadian Partnership Against Cancer manages the OncoSim program, with funding from Health Canada and model development by Statistics Canada. Microsimulation modelling allows for the detailed capture of population heterogeneity and health and demographic history over time. Extensive data from multiple Canadian sources were used as inputs or to validate the model. OncoSim has been validated through expert consultation; assessments of face validity, internal validity, and external validity; and model fit against observed data. The platform comprises three in-depth cancer models (lung, colorectal, cervical), with another in-depth model (breast) and a generalized model (25 cancers) being in development. Unique among models of its class, OncoSim is available online for public sector use free of charge. Users can customize input values and output display, and extensive user support is provided. OncoSim has been used to support decision-making at the national and jurisdictional levels. Although simulation studies are generally not included in hierarchies of evidence, they are integral to informing cancer control policy when clinical studies are not feasible. OncoSim can evaluate complex intervention scenarios for multiple cancers. Canadian decision-makers thus have a powerful tool to assess the costs, benefits, cost-effectiveness, and budgetary effects of cancer control interventions when faced with difficult choices for improvements in population health and resource allocation.

8.
Phys Rev Lett ; 117(15): 151803, 2016 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-27768323

RESUMO

We report results of a search for oscillations involving a light sterile neutrino over distances of 1.04 and 735 km in a ν_{µ}-dominated beam with a peak energy of 3 GeV. The data, from an exposure of 10.56×10^{20} protons on target, are analyzed using a phenomenological model with one sterile neutrino. We constrain the mixing parameters θ_{24} and Δm_{41}^{2} and set limits on parameters of the four-dimensional Pontecorvo-Maki-Nakagawa-Sakata matrix, |U_{µ4}|^{2} and |U_{τ4}|^{2}, under the assumption that mixing between ν_{e} and ν_{s} is negligible (|U_{e4}|^{2}=0). No evidence for ν_{µ}→ν_{s} transitions is found and we set a world-leading limit on θ_{24} for values of Δm_{41}^{2}≲1 eV^{2}.

9.
Curr Oncol ; 23(3): e179-87, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27330355

RESUMO

BACKGROUND: Low-dose computed tomography (ldct) screening has been shown to reduce mortality from lung cancer; however, the optimal screening duration and "at risk" population are not known. METHODS: The Cancer Risk Management Model developed by Statistics Canada for the Canadian Partnership Against Cancer includes a lung screening module based on data from the U.S. National Lung Screening Trial (nlst). The base-case scenario reproduces nlst outcomes with high fidelity. The impact in Canada of annual screening on the number of incident cases and life-years gained, with a wider range of age and smoking history eligibility criteria and varied participation rates, was modelled to show the magnitude of clinical benefit nationally and by province. Life-years gained, costs (discounted and undiscounted), and resource requirements were also estimated. RESULTS: In 2014, 1.4 million Canadians were eligible for screening according to nlst criteria. Over 10 years, screening would detect 12,500 more lung cancers than the expected 268,300 and would gain 9200 life-years. The computed tomography imaging requirement of 24,000-30,000 at program initiation would rise to between 87,000 and 113,000 by the 5th year of an annual nlst-like screening program. Costs would increase from approximately $75 million to $128 million at 10 years, and the cumulative cost nationally over 10 years would approach $1 billion, partially offset by a reduction in the costs of managing advanced lung cancer. CONCLUSIONS: Modelling various ways in which ldct might be implemented provides decision-makers with estimates of the effect on clinical benefit and on resource needs that clinical trial results are unable to provide.

10.
Curr Oncol ; 23(Suppl 1): S56-63, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26985148

RESUMO

BACKGROUND: In Canada, discussion about changing from cytology to human papillomavirus (hpv) dna testing for primary screening in cervical cancer is ongoing. However, the Canadian Task Force on Preventive Health Care has not yet made a recommendation, concluding that the evidence is insufficient. METHODS: We used the cervical cancer and hpv transmission models of the Cancer Risk Management Model to study the health and economic outcomes of primary cytology compared with hpv dna testing in 14 screening scenarios with varying screening modalities and intervals. Projected cervical cancer cases, deaths, colposcopies, screens, costs, and incremental cost-effectiveness were evaluated. We performed sensitivity analyses for hpv dna test costs. RESULTS: Compared with triennial cytology from age 25, 5-yearly hpv dna screening alone from age 30 resulted in equivalent incident cases and deaths, but 55% (82,000) fewer colposcopies and 43% (1,195,000) fewer screens. At hpv dna screening intervals of 3 years, whether alone or in an age-based sequence with cytology, screening costs are greater, but at intervals of more than 5 years, they are lower. Scenarios on the cost-effectiveness frontier were hpv dna testing alone every 10, 7.5, 5, or 3 years, and triennial cytology starting at age 21 or 25 when combined with hpv dna testing every 3 years. CONCLUSIONS: Changing from cytology to hpv dna testing as the primary screening test for cervical cancer would be an acceptable strategy in Canada with respect to incidence, mortality, screening and diagnostic test volumes.

11.
Osteoarthritis Cartilage ; 23(10): 1654-63, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26050868

RESUMO

OBJECTIVES: To estimate the future direct cost of OA in Canada using a population-based health microsimulation model of osteoarthritis (POHEM-OA). METHODS: We used administrative health data from the province of British Columbia (BC), Canada, a survey of a random sample of BC residents diagnosed with OA (Ministry of Health of BC data), Canadian Institute of Health Information (CIHI) cost data and literature estimates to populate a microsimulation model. Cost components associated with pharmacological and non-pharmacological treatments, total joint replacement (TJR) surgery, as well as use of hospital resources and management of complications arising from the treatment of osteoarthritis (OA) were included. Future costs were then simulated using the POHEM-OA model to construct profiles for each adult Canadian. RESULTS: From 2010 to 2031, as the prevalence of OA is projected to increase from 13.8% to 18.6%, the total direct cost of OA is projected to increase from $2.9 billion to $7.6 billion, an almost 2.6-fold increase (in 2010 $CAD). From the highest to the lowest, the cost components that will constitute the total direct cost of OA in 2031 are hospitalization cost ($2.9 billion), outpatient services ($1.2 billion), alternative care and out-of-pocket cost categories ($1.2 billion), drugs ($1 billion), rehabilitation ($0.7 billion) and side-effect of drugs ($0.6 billion). CONCLUSIONS: Projecting the future trends in the cost of OA enables policy makers to anticipate the significant shifts in its distribution of burden in the future.


Assuntos
Assistência Ambulatorial/economia , Analgésicos/economia , Artroplastia de Substituição/economia , Custos de Cuidados de Saúde , Hospitalização/economia , Osteoartrite/economia , Modalidades de Fisioterapia/economia , Colúmbia Britânica , Canadá , Simulação por Computador , Bases de Dados Factuais , Custos de Medicamentos , Humanos , Osteoartrite/terapia
12.
Curr Oncol ; 22(2): e41-50, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25908920

RESUMO

BACKGROUND: Several screening methods for colorectal cancer (crc) are available, and some have been shown by randomized trials to be effective. In the present study, we used a well-developed population health simulation model to compare the risks and benefits of a variety of screening scenarios. Tests considered were the fecal occult blood test (fobt), the fecal immunochemical test (fit), flexible sigmoidoscopy, and colonoscopy. Outcomes considered included years of life gained, crc cases and deaths prevented, and direct health system costs. METHODS: A natural history model of crc was implemented and calibrated to specified targets within the framework of the Cancer Risk Management Model (crmm) from the Canadian Partnership Against Cancer. The crmm-crc permits users to enter their own parameter values or to use program-specified base values. For each of 23 screening scenarios, we used the crmm-crc to run 10 million replicate simulations. RESULTS: Using base parameter values and some user-specified values in the crmm-crc, and comparing our screening scenarios with no screening, all screening scenarios were found to reduce the incidence of and mortality from crc. The fobt was the least effective test; it was not associated with lower net cost. Colonoscopy screening was the most effective test; it had net costs comparable to those for several other strategies considered, but required more than 3 times the colonoscopy resources needed by other approaches. After colonoscopy, strategies based on the fit were predicted to be the most effective. In sensitivity analyses performed for the fobt and fit screening strategies, fobt parameter values associated with high-sensitivity formulations were associated with a substantial increase in test effectiveness. The fit was more cost-effective at the 50 ng/mL threshold than at the 100 ng/mL threshold. CONCLUSIONS: The crmm-crc provides a sophisticated and flexible environment in which to evaluate crc control options. All screening scenarios considered in this study effectively reduced crc mortality, although sensitivity analyses demonstrated some uncertainty in the magnitude of the improvements. Where possible, local data should be used to reduce uncertainty in the parameters.

13.
RNA ; 18(10): 1796-804, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22912485

RESUMO

miRNAs are ∼22-nt RNAs that bind to the Argonaute family of proteins and have important regulatory roles in plants and animals. Here, we show that miRNAs exhibit targeting activity in cells when delivered as single strands that are 5'-phosphorylated and that contain 2'-fluoro ribose modifications. Length preferences, chemical modification sensitivity, and genome-wide seed-based targeting all suggest that this activity is Ago-based. Activity could be enhanced by annealing of segmented passenger strands containing non-nucleic acid spacers. Furthermore, screening of randomly generated sequences identified pyrimidine rich 3' cassette sequences that increased single strand activity. These results provide an initial step in the development of single-stranded miRNA mimics for therapeutic use.


Assuntos
DNA de Cadeia Simples/síntese química , MicroRNAs/química , Mimetismo Molecular , Sequência de Bases , Clonagem Molecular , DNA de Cadeia Simples/química , Fluoretos/síntese química , Fluoretos/química , Técnicas de Silenciamento de Genes/instrumentação , Técnicas de Silenciamento de Genes/métodos , Células HCT116 , Ensaios de Triagem em Larga Escala , Humanos , Análise em Microsséries , Mimetismo Molecular/fisiologia , Dados de Sequência Molecular , Fosforilação , Ribose/síntese química , Ribose/química , Transfecção
14.
Bioconjug Chem ; 25(12): 2222-32, 2014 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-25398098

RESUMO

Chemical modification of siRNA is achieved in a high-throughput manner (96-well plate format) by copper catalyzed azide-alkyne cycloadditions. This transformation can be performed in one synthetic operation at up to four positions with complete specificity, good yield, and acceptable purity. As demonstrated here, this approach extends the current synthetic options for oligonucleotide modifications and simultaneously facilitates the systematic, rapid biological evaluation of modified siRNA.


Assuntos
Ensaios de Triagem em Larga Escala/métodos , Oligonucleotídeos/química , Oligonucleotídeos/farmacologia , Relação Estrutura-Atividade , Alcinos/química , Azidas/química , Catálise , Cromatografia Líquida de Alta Pressão/métodos , Química Click , Cobre/química , Reação de Cicloadição , Técnicas de Silenciamento de Genes , Células HeLa , Humanos , RNA Interferente Pequeno/química , RNA Interferente Pequeno/farmacologia , Técnicas de Síntese em Fase Sólida
15.
Nucleic Acids Res ; 40(9): 4125-36, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22253019

RESUMO

While RNAi has traditionally relied on RNA duplexes, early evaluation of siRNAs demonstrated activity of the guide strand in the absence of the passenger strand. However, these single strands lacked the activity of duplex RNAs. Here, we report the systematic use of chemical modifications to optimize single-strand RNA (ssRNA)-mediated mRNA knockdown. We identify that 2'F ribose modifications coupled with 5'-end phosphorylation vastly improves ssRNA activity both in vitro and in vivo. The impact of specific chemical modifications on ssRNA activity implies an Ago-mediated mechanism but the hallmark mRNA cleavage sites were not observed which suggests ssRNA may operate through a mechanism beyond conventional Ago2 slicer activity. While currently less potent than duplex siRNAs, with additional chemical optimization and alternative routes of delivery, chemically modified ssRNAs could represent a powerful RNAi platform.


Assuntos
Interferência de RNA , Pequeno RNA não Traduzido/química , Animais , Proteínas Argonautas/metabolismo , Linhagem Celular , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/química , Pequeno RNA não Traduzido/metabolismo
16.
J Lipid Res ; 53(5): 859-867, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22355095

RESUMO

Microsomal triglyceride transfer protein (Mtp) inhibitors represent a novel therapeutic approach to lower circulating LDL cholesterol, although therapeutic development has been hindered by the observed increase in hepatic triglycerides and liver steatosis following treatment. Here, we used small interfering RNAs (siRNA) targeting Mtp to achieve target-specific silencing to study this phenomenon and to determine to what extent liver steatosis is induced by changes in Mtp expression. We observed that Mtp silencing led to a decrease in many genes involved in hepatic triglyceride synthesis. Given the role of diacylglycerol O-acyltransferase 2 (Dgat2) in regulating hepatic triglyceride synthesis, we then evaluated whether target-specific silencing of both Dgat2 and Mtp were sufficient to attenuate Mtp silencing-induced liver steatosis. We showed that the simultaneous inhibition of Dgat2 and Mtp led to a decrease in plasma cholesterol and a reduction in the accumulation of hepatic triglycerides caused by the inhibition of Mtp. Collectively, these findings provide a proof-of-principle for a triglyceride synthesis/Mtp inhibitor combination and represent a potentially novel approach for therapeutic development in which targeting multiple pathways can achieve the desired response.


Assuntos
Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Diacilglicerol O-Aciltransferase/deficiência , Diacilglicerol O-Aciltransferase/genética , Fígado Gorduroso/genética , Inativação Gênica , RNA Interferente Pequeno/genética , Animais , Apolipoproteínas B/deficiência , Apolipoproteínas B/genética , Colesterol/sangue , Fígado Gorduroso/sangue , Fígado Gorduroso/enzimologia , Fígado Gorduroso/metabolismo , Fígado/metabolismo , Masculino , Camundongos , Triglicerídeos/metabolismo
17.
RNA ; 16(12): 2336-40, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-20971811

RESUMO

microRNAs are ∼ 22 nucleotide regulatory RNAs that are processed into duplexes from hairpin structures and incorporated into Argonaute proteins. Here, we show that a nick in the middle of the guide strand of an miRNA sequence allows for seed-based targeting characteristic of miRNA activity. Insertion of an inverted abasic, a dye, or a small gap between the two segments still permits target knockdown. While activity from the seed region of the segmented miRNA is apparent, activity from the 3' half of the guide strand is impaired, suggesting that an intact guide backbone is required for contribution from the 3' half. miRNA activity was also observed following nicking of a miRNA precursor. These results illustrate a structural flexibility in miRNA duplexes and may have applications in the design of miRNA mimetics.


Assuntos
Marcação de Genes/métodos , MicroRNAs/metabolismo , Processamento Pós-Transcricional do RNA/fisiologia , Deleção de Sequência/fisiologia , Sequência de Bases/genética , Sequência de Bases/fisiologia , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Células HCT116 , Humanos , MicroRNAs/química , MicroRNAs/genética , MicroRNAs/fisiologia , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Reação em Cadeia da Polimerase , Ribonuclease III/metabolismo , Ribonuclease III/fisiologia , Deleção de Sequência/genética , Moldes Genéticos , Transfecção , Pequeno RNA não Traduzido
18.
Nucleic Acids Res ; 38(2): 660-71, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19917641

RESUMO

Small interfering RNAs (siRNAs) are short, double-stranded RNAs that use the endogenous RNAi pathway to mediate gene silencing. Phosphorylation facilitates loading of a siRNA into the Ago2 complex and subsequent cleavage of the target mRNA. In this study, 2', 3' seco nucleoside modifications, which contain an acylic ribose ring and are commonly called unlocked nucleic acids (UNAs), were evaluated at all positions along the guide strand of a siRNA targeting apolipoprotein B (ApoB). UNA modifications at positions 1, 2 and 3 were detrimental to siRNA activity. UNAs at positions 1 and 2 prevented phosphorylation by Clp1 kinase, abrogated binding to Ago2, and impaired Ago2-mediated cleavage of the mRNA target. The addition of a 5'-terminal phosphate to siRNA containing a position 1 UNA restored ApoB mRNA silencing, Ago2 binding, and Ago2 mediated cleavage activity. Position 1 UNA modified siRNA containing a 5'-terminal phosphate exhibited a partial restoration of siRNA silencing activity in vivo. These data reveal the complexity of interpreting the effects of chemical modification on siRNA activity, and exemplify the importance of using multiple biochemical, cell-based and in vivo assays to rationally design chemically modified siRNA destined for therapeutic use.


Assuntos
Nucleosídeos/química , Interferência de RNA , RNA Interferente Pequeno/química , Animais , Apolipoproteínas B/genética , Linhagem Celular , Fator de Iniciação 2 em Eucariotos/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Nucleares/metabolismo , Fosforilação , Fosfotransferases/metabolismo , RNA Interferente Pequeno/metabolismo , Termodinâmica , Fatores de Transcrição/metabolismo , Pequeno RNA não Traduzido
19.
J Lipid Res ; 52(4): 679-87, 2011 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21262787

RESUMO

Reducing circulating LDL-cholesterol (LDL-c) reduces the risk of cardiovascular disease in people with hypercholesterolemia. Current approaches to reduce circulating LDL-c include statins, which inhibit cholesterol synthesis, and ezetimibe, which blocks cholesterol absorption. Both elevate serum PCSK9 protein levels in patients, which could attenuate their efficacy by reducing the amount of cholesterol cleared from circulation. To determine whether PCSK9 inhibition could enhance LDL-c lowering of both statins and ezetimibe, we utilized small interfering RNAs (siRNAs) to knock down Pcsk9, together with ezetimibe, rosuvastatin, and an ezetimibe/rosuvastatin combination in a mouse model with a human-like lipid profile. We found that ezetimibe, rosuvastatin, and ezetimibe/rosuvastatin combined lower serum cholesterol but induce the expression of Pcsk9 as well as the Srebp-2 hepatic cholesterol biosynthesis pathway. Pcsk9 knockdown in combination with either treatment led to greater reductions in serum non-HDL with a near-uniform reduction of all LDL-c subfractions. In addition to reducing serum cholesterol, the combined rosuvastatin/ezetimibe/Pcsk9 siRNA treatment exhibited a significant reduction in serum APOB protein and triglyceride levels. Taken together, these data provide evidence that PCSK9 inhibitors, in combination with current therapies, have the potential to achieve greater reductions in both serum cholesterol and triglycerides.


Assuntos
Anticolesterolemiantes/uso terapêutico , Azetidinas/uso terapêutico , Fluorbenzenos/uso terapêutico , Pirimidinas/uso terapêutico , Serina Endopeptidases/metabolismo , Sulfonamidas/uso terapêutico , Animais , Apolipoproteínas B/sangue , Colesterol/sangue , LDL-Colesterol/sangue , Ensaio de Imunoadsorção Enzimática , Ezetimiba , Hipercolesterolemia/sangue , Hipercolesterolemia/tratamento farmacológico , Hipercolesterolemia/terapia , Camundongos , Camundongos Endogâmicos C57BL , Pró-Proteína Convertase 9 , Pró-Proteína Convertases , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Rosuvastatina Cálcica , Serina Endopeptidases/genética , Triglicerídeos/sangue
20.
Mol Pharmacol ; 79(6): 953-63, 2011 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-21427169

RESUMO

Deeper knowledge of pharmacokinetic and pharmacodynamic (PK/PD) concepts for RNA therapeutics is important to streamline the drug development process and for rigorous selection of best performing drug candidates. Here we characterized the PK/PD relationship for small interfering RNAs (siRNAs) targeting luciferase by examining siRNA concentration in plasma and liver, the temporal RNA-induced silencing complex binding profiles, mRNA reduction, and protein inhibition measured by noninvasive bioluminescent imaging. A dose-dependent and time-related decrease in bioluminescence was detected over 25 days after a single treatment of a lipid nanoparticle-formulated siRNA targeting luciferase messenger RNA. A direct relationship was observed between the degree of in vivo mRNA and protein reduction and the Argonaute2 (Ago2)-bound siRNA fraction but not with the total amount of siRNA found in the liver, suggesting that the Ago2-siRNA complex is the key determinant of target inhibition. These observations were confirmed for an additional siRNA that targets endogenously expressed Sjögren syndrome antigen B (Ssb) mRNA, indicating that our observations are not limited to a transgenic mouse system. Our data provide detailed information of the temporal regulation of siRNA liver delivery, Ago2 loading, mRNA reduction, and protein inhibition that are essential for the rapid and cost-effective clinical development of siRNAs therapeutics.


Assuntos
Inativação Gênica , RNA Interferente Pequeno/genética , Animais , Sequência de Bases , Primers do DNA , Camundongos , Camundongos Transgênicos , Reação em Cadeia da Polimerase
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