Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 26
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
País de afiliação
Intervalo de ano de publicação
1.
J Am Chem Soc ; 137(14): 4598-601, 2015 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-25789886

RESUMO

N-(4-Chloro-3-(trifluoromethyl)phenyl)-2-ethoxybenzamide (CTB) is a small molecule that functions by altering the chromatin architecture to modulate gene expression. We report a new CTB derivative with increased solubility and demonstrate CTB's functionality by conjugating it on the recently established NanoScript platform to enhance gene expression and induce stem cell differentiation. NanoScript is a nanoparticle-based artificial transcription factor that emulates the structure and function of transcription factor proteins (TFs) to effectively regulate endogenous gene expression. Modifying NanoScript with CTB will more closely replicate the TF structure and enhance CTB functionality and gene expression. To this end, we first conjugated CTB onto NanoScript and initiated a time-dependent increase in histone acetyltransferase activity. Next, because CTB is known to trigger the pathway involved in regulating Sox9, a master regulator of chondrogenic differentiation, we modifed a Sox9-specific NanoScript with CTB to enhance chondrogenic gene activity and differentiation. Because NanoScript is a tunable and robust platform, it has potential for various gene-regulating applications, such as stem cell differentiation.


Assuntos
Materiais Biomiméticos/química , Materiais Biomiméticos/farmacologia , Condrogênese/efeitos dos fármacos , Epigênese Genética/efeitos dos fármacos , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Nanopartículas/química , Benzamidas/química , Condrogênese/genética , Fatores de Transcrição/metabolismo
2.
Angew Chem Int Ed Engl ; 54(41): 11983-8, 2015 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-26292201

RESUMO

Even though gene repression is a powerful approach to exogenously regulate cellular behavior, developing a platform to effectively repress targeted genes, especially for stem-cell applications, remains elusive. Herein, we introduce a nanomaterial-based platform that is capable of mimicking the function of transcription repressor proteins to downregulate gene expression at the transcriptional level for enhancing stem-cell differentiation. We developed the "NanoScript" platform by integrating multiple gene repression molecules with a nanoparticle. First, we show a proof-of-concept demonstration using a GFP-specific NanoScript to knockdown GFP expression in neural stem cells (NSCs-GFP). Then, we show that a Sox9-specific NanoScript can repress Sox9 expression to initiate enhanced differentiation of NSCs into functional neurons. Overall, the tunable properties and gene-knockdown capabilities of NanoScript enables its utilization for gene-repression applications in stem cell biology.


Assuntos
Materiais Biomiméticos/metabolismo , Biomimética/métodos , Técnicas de Silenciamento de Genes/métodos , Nanopartículas/metabolismo , Células-Tronco Neurais/citologia , Neurogênese , Neurônios/citologia , Materiais Biomiméticos/química , Expressão Gênica , Proteínas de Fluorescência Verde/genética , Humanos , Nanopartículas/química , Células-Tronco Neurais/metabolismo , Neurônios/metabolismo , Nylons/química , Nylons/metabolismo , Regiões Promotoras Genéticas , Proteínas Repressoras/química , Proteínas Repressoras/metabolismo , Fatores de Transcrição SOX9/genética
3.
Small ; 10(20): 4106-12, 2014 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-24947843

RESUMO

A novel therapy is demonstrated utilizing magnetic nanoparticles for the dual purpose of delivering microRNA and inducing magnetic hyperthermia. In particular, the combination of lethal-7a microRNA (let-7a), which targets a number of the survival pathways that typically limit the effectiveness of hyperthermia, with magnetic hyperthermia greatly enhances apoptosis in brain cancer cells.


Assuntos
Apoptose , Neoplasias Encefálicas/patologia , Glioblastoma/patologia , Hipertermia Induzida , Magnetismo , MicroRNAs/administração & dosagem , Nanopartículas , Neoplasias Encefálicas/terapia , Humanos
4.
Adv Sci (Weinh) ; 11(24): e2306432, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38647391

RESUMO

The CRISPR-Cas9 technology has the potential to revolutionize the treatment of various diseases, including Rett syndrome, by enabling the correction of genes or mutations in human patient cells. However, several challenges need to be addressed before its widespread clinical application. These challenges include the low delivery efficiencies to target cells, the actual efficiency of the genome-editing process, and the precision with which the CRISPR-Cas system operates. Herein, the study presents a Magnetic Nanoparticle-Assisted Genome Editing (MAGE) platform, which significantly improves the transfection efficiency, biocompatibility, and genome-editing accuracy of CRISPR-Cas9 technology. To demonstrate the feasibility of the developed technology, MAGE is applied to correct the mutated MeCP2 gene in induced pluripotent stem cell-derived neural progenitor cells (iPSC-NPCs) from a Rett syndrome patient. By combining magnetofection and magnetic-activated cell sorting, MAGE achieves higher multi-plasmid delivery (99.3%) and repairing efficiencies (42.95%) with significantly shorter incubation times than conventional transfection agents without size limitations on plasmids. The repaired iPSC-NPCs showed similar characteristics as wild-type neurons when they differentiated into neurons, further validating MAGE and its potential for future clinical applications. In short, the developed nanobio-combined CRISPR-Cas9 technology offers the potential for various clinical applications, particularly in stem cell therapies targeting different genetic diseases.


Assuntos
Sistemas CRISPR-Cas , Edição de Genes , Síndrome de Rett , Síndrome de Rett/genética , Síndrome de Rett/terapia , Sistemas CRISPR-Cas/genética , Edição de Genes/métodos , Humanos , Células-Tronco Pluripotentes Induzidas , Nanopartículas de Magnetita , Proteína 2 de Ligação a Metil-CpG/genética , Terapia Genética/métodos
5.
Phys Chem Chem Phys ; 15(31): 12785-99, 2013 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-23828095

RESUMO

Graphene is a single-atom thick, two-dimensional sheet of carbon that is characterized by exceptional chemical, electrical, material, optical, and physical properties. As a result, graphene and related materials, such as graphene oxide and reduced graphene oxide, have been brought to the forefront in the field of sensing. Recently, a number of reports have demonstrated that graphene-nanoparticle hybrid structures can act synergistically to offer a number of unique physicochemical properties that are desirable and advantageous for sensing applications. These graphene-nanoparticle hybrid structures are particularly interesting because not only do they display the individual properties of the nanoparticles and of graphene, but they can also exhibit additional synergistic properties thereby enhancing the achievable sensitivity and selectivity using a variety of sensing mechanisms. As such, in this perspective, we will discuss the progress that has been made in the development and application of graphene-nanoparticle hybrid sensors and their future prospects. In particular, we will focus on the preparation of graphene-nanoparticle hybrid structures as well as their application in electronic, electrochemical, and optical sensors.


Assuntos
Grafite/química , Nanopartículas/química , Técnicas Eletroquímicas , Dispositivos Ópticos
7.
Pharmacoecon Open ; 6(5): 711-721, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35871127

RESUMO

BACKGROUND: The use of drug utilization management techniques such as formulary exclusions, prior authorizations, and step edits has risen sharply during the last decade, contributing to growing administrative costs for physician practices. However, limited data exist on the extent of these administrative costs, with previous studies relying on data from over a decade ago. OBJECTIVE: The aim of this study was to assess physician and practice administrator experiences with drug utilization management. METHODS: A national survey was conducted between 9 February and 30 March 2021, targeting 925 physicians and administrators working at medical practices in the US. Time spent by physicians and their staff on tasks related to drug utilization management for prescription medications was collected and used to calculate the dollar value of that time. RESULTS: We estimated that physicians spent a median of 4.0 h per week on drug utilization management, while nurses spent 15.0 h and other staff spent between 3.6 and 10.0 h on drug utilization management per physician per week. This time was associated with a calculated median dollar value of $75,927 per physician per year. Extrapolating this estimate to a national scale suggests that time spent annually by physician practices on drug utilization management could be valued at more than $43 billion. CONCLUSIONS: Drug utilization management results in significant time spent by US physician practices, which in turn, results in meaningful costs to these practices. As the prevalence of drug utilization management continues to grow, the impact on physician practices will remain an important topic.

8.
JAMA Health Forum ; 3(5): e221167, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35977254

RESUMO

This cohort study uses a longitudinal access and adjudication data set to evaluate prescription out-of-pocket costs and filling behaviors of commercially insured individuals with chronic obstructive pulmonary disease (COPD).


Assuntos
Gastos em Saúde , Doença Pulmonar Obstrutiva Crônica , Estudos de Coortes , Humanos , Prescrições , Doença Pulmonar Obstrutiva Crônica/terapia , Estudos Retrospectivos
9.
PLoS One ; 17(9): e0274772, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36126062

RESUMO

The use of drug utilization management techniques such as formulary exclusions, prior authorizations, and step edits has risen sharply during the last decade, contributing to the growing burden on physicians and patients. Limited quantitative data exist, however, on physician perceptions of drug utilization management. A national survey was conducted between February 9 and March 30, 2021, targeting office-based physicians working in the United States to assess their perceptions on drug utilization management in their practice. Of the 742 physicians that participated in the study, over 80% reported deciding against prescribing certain treatments in anticipation of drug utilization management at least sometimes (>50% of the time). Despite utilization management having an impact on prescribing decisions, about half of physicians said that the utilization management policies they encounter rarely or never (0-25% of the time) align with clinical evidence.


Assuntos
Uso de Medicamentos , Médicos , Humanos , Consultórios Médicos , Estados Unidos
10.
Health Aff (Millwood) ; 40(8): 1206-1214, 2021 08.
Artigo em Inglês | MEDLINE | ID: mdl-34339243

RESUMO

The continuing launch of innovative but high-price drugs has intensified efforts by payers to manage use and spending and by pharmaceutical manufacturers to support patient access and sales. Payers are restricting drug formularies, requiring more stringent prior authorizations, and raising patient cost-sharing requirements. Manufacturers are investing in programs that help patients and physician practices navigate administrative controls and help patients meet cost-sharing obligations. Based on a compilation and analysis of the existing peer-reviewed and professional literature, this article estimates that payers, manufacturers, physicians, and patients together incur approximately $93.3 billion in costs annually on implementing, contesting, and navigating utilization management. Payers spend approximately $6.0 billion annually administering drug utilization management, and manufacturers spend approximately $24.8 billion supporting patient access in response. Physicians devote approximately $26.7 billion in time spent navigating utilization management, whereas patients spend approximately $35.8 billion annually in drug cost sharing, even after taking advantage of manufacturer and philanthropic sources of financial support. All stakeholders in the US pharmaceutical system would benefit from a deescalation of utilization management, combining lower drug prices with lower barriers to patient access.


Assuntos
Efeitos Psicossociais da Doença , Médicos , Custo Compartilhado de Seguro , Custos de Medicamentos , Uso de Medicamentos , Humanos , Estados Unidos
12.
ACS Appl Mater Interfaces ; 10(32): 26954-26963, 2018 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-30028120

RESUMO

In this study, we report the use of a multifunctional magnetic core-shell nanoparticle (MCNP), composed of a highly magnetic zinc-doped iron oxide (ZnFe2O4) core nanoparticle and a biocompatible mesoporous silica (mSi) shell, for the simultaneous delivery of let-7a microRNA (miRNA) and anticancer drugs (e.g., doxorubicin) to overcome chemoresistance in breast cancer. Owing to the ability of let-7a to repress DNA repair mechanisms (e.g., BRCA1 and BRCA2) and downregulate drug efflux pumps (e.g., ABCG2), delivery of let-7a could sensitize chemoresistant breast cancer cells (MDA-MB-231) to subsequent doxorubicin chemotherapy both in vitro and in vivo. Moreover, the multifunctionality of our MCNPs allows for the monitoring of in vivo delivery via magnetic resonance imaging. In short, we have developed a multifunctional MCNP-based therapeutic approach to provide an attractive method with which to enhance our ability not only to deliver combined miRNA therapeutics with small-molecule drugs in both selective and effective manner but also to sensitize cancer cells for the enhanced treatment via the combination of miRNA replacement therapy using a single nanoplatform.


Assuntos
Nanopartículas de Magnetita , Doxorrubicina , Sistemas de Liberação de Medicamentos , Resistencia a Medicamentos Antineoplásicos , Humanos , Imageamento por Ressonância Magnética , Magnetismo , MicroRNAs , Neoplasias
13.
Adv Healthc Mater ; 5(1): 10-55, 2016 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-25772134

RESUMO

Stem cells are characterized by a number of useful properties, including their ability to migrate, differentiate, and secrete a variety of therapeutic molecules such as immunomodulatory factors. As such, numerous pre-clinical and clinical studies have utilized stem cell-based therapies and demonstrated their tremendous potential for the treatment of various human diseases and disorders. Recently, efforts have focused on engineering stem cells in order to further enhance their innate abilities as well as to confer them with new functionalities, which can then be used in various biomedical applications. These engineered stem cells can take on a number of forms. For instance, engineered stem cells encompass the genetic modification of stem cells as well as the use of stem cells for gene delivery, nanoparticle loading and delivery, and even small molecule drug delivery. The present Review gives an in-depth account of the current status of engineered stem cells, including potential cell sources, the most common methods used to engineer stem cells, and the utilization of engineered stem cells in various biomedical applications, with a particular focus on tissue regeneration, the treatment of immunodeficiency diseases, and cancer.


Assuntos
Tecnologia Biomédica/métodos , Células-Tronco/citologia , Engenharia Tecidual/métodos , Animais , Terapia Genética , Humanos , Neoplasias/terapia , Regeneração
14.
Health Aff (Millwood) ; 40(11): 1814-1815, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34724421
15.
Biomaterials ; 81: 46-57, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26720500

RESUMO

Stem cell-based gene therapies, wherein stem cells are genetically engineered to express therapeutic molecules, have shown tremendous potential for cancer applications owing to their innate ability to home to tumors. However, traditional stem cell-based gene therapies are hampered by our current inability to control when the therapeutic genes are actually turned on, thereby resulting in detrimental side effects. Here, we report the novel application of magnetic core-shell nanoparticles for the dual purpose of delivering and activating a heat-inducible gene vector that encodes TNF-related apoptosis-inducing ligand (TRAIL) in adipose-derived mesenchymal stem cells (AD-MSCs). By combining the tumor tropism of the AD-MSCs with the spatiotemporal MCNP-based delivery and activation of TRAIL expression, this platform provides an attractive means with which to enhance our control over the activation of stem cell-based gene therapies. In particular, we found that these engineered AD-MSCs retained their innate ability to proliferate, differentiate, and, most importantly, home to tumors, making them ideal cellular carriers. Moreover, exposure of the engineered AD-MSCS to mild magnetic hyperthermia resulted in the selective expression of TRAIL from the engineered AD-MSCs and, as a result, induced significant ovarian cancer cell death in vitro and in vivo.


Assuntos
Terapia Genética , Hipertermia Induzida , Magnetismo , Transplante de Células-Tronco Mesenquimais , Células-Tronco Mesenquimais/citologia , Neoplasias Ovarianas/terapia , Animais , Apoptose , Diferenciação Celular , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Feminino , Temperatura Alta , Humanos , Camundongos Nus , Nanopartículas/química , Nanopartículas/ultraestrutura , Neoplasias Ovarianas/patologia , Plasmídeos/metabolismo , Polietilenoimina/química , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo
16.
ACS Nano ; 9(7): 6909-17, 2015 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-26108385

RESUMO

Transcription factors (TFs) are multidomain proteins that play a critical role in orchestrating stem cell differentiation, but several limitations hinder the full potential of TF-based gene regulation. Here we report a unique strategy to emulate TFs and differentiate stem cells in a nonviral approach using an artificial, nanoparticle-based transcription factor called NanoScript. The NanoScript platform consists of a gold nanoparticle functionalized with small molecules that mimic the various domains of TFs. As a result, NanoScript mimics the function and structure of TF proteins. Specifically, NanoScript was designed to regulate muscle cell differentiation by targeting myogenic regulatory factors (MRFs), which play an important role in inducing myogenesis. This NanoScript-MRF is stable in physiological environments, localizes within the nucleus, induces differentiation of adipose-derived mesenchymal stem cells into mature muscle cells in 7 days, and is naturally excreted from induced muscle cells. As such, NanoScript represents a safe and powerful tool for applications requiring gene manipulation.


Assuntos
Células-Tronco Mesenquimais/citologia , Nanopartículas Metálicas , Células Musculares/citologia , Desenvolvimento Muscular , Fatores de Regulação Miogênica/administração & dosagem , Diferenciação Celular , Linhagem Celular , Ouro , Humanos , Células-Tronco Mesenquimais/metabolismo , Células Musculares/metabolismo , Fatores de Regulação Miogênica/genética
17.
ACS Nano ; 9(4): 3780-90, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25840606

RESUMO

Control of stem cell fate by modulating biophysical cues (e.g., micropatterns, nanopatterns, elasticity and porosity of the substrates) has emerged as an attractive approach in stem cell-based research. Here, we report a method for fabricating combinatorial patterns of graphene oxide (GO) to effectively control the differentiation of human adipose-derived mesenchymal stem cells (hADMSCs). In particular, GO line patterns were highly effective for modulating the morphology of hADMSCs, resulting in enhanced differentiation of hADMSCs into osteoblasts. Moreover, by generating GO grid patterns, we demonstrate the highly efficient conversion of mesodermal stem cells to ectodermal neuronal cells (conversion efficiency = 30%), due to the ability of the grid patterns to mimic interconnected/elongated neuronal networks. This work provides an early demonstration of developing combinatorial graphene hybrid-pattern arrays for the control of stem cell differentiation, which can potentially lead to more effective stem cell-based treatment of incurable diseases/disorders.


Assuntos
Tecido Adiposo/citologia , Diferenciação Celular/efeitos dos fármacos , Grafite/química , Grafite/farmacologia , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Humanos , Modelos Moleculares , Conformação Molecular , Nanomedicina , Osteogênese/efeitos dos fármacos , Óxidos/química
19.
ACS Nano ; 8(9): 8959-67, 2014 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-25133310

RESUMO

Transcription factor (TF) proteins are master regulators of transcriptional activity and gene expression. TF-based gene regulation is a promising approach for many biological applications; however, several limitations hinder the full potential of TFs. Herein, we developed an artificial, nanoparticle-based transcription factor, termed NanoScript, which is designed to mimic the structure and function of TFs. NanoScript was constructed by tethering functional peptides and small molecules called synthetic transcription factors, which mimic the individual TF domains, onto gold nanoparticles. We demonstrate that NanoScript localizes within the nucleus and initiates transcription of a reporter plasmid by over 15-fold. Moreover, NanoScript can effectively transcribe targeted genes on endogenous DNA in a nonviral manner. Because NanoScript is a functional replica of TF proteins and a tunable gene-regulating platform, it has great potential for various stem cell applications.


Assuntos
Materiais Biomiméticos/química , Materiais Biomiméticos/metabolismo , Regulação da Expressão Gênica , Nanopartículas Metálicas , Nanopartículas , Fatores de Transcrição/metabolismo , Núcleo Celular/metabolismo , Ouro/química , Células HeLa , Humanos , Peptídeos/química , Estrutura Terciária de Proteína , Fatores de Transcrição/química , Ativação Transcricional
20.
Sci Rep ; 3: 1553, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23531983

RESUMO

RNA interference (RNAi) for controlling gene expression levels using siRNA or miRNA is emerging as an important tool in stem cell biology. However, the conventional methods used to deliver siRNA into stem cells result in significant cytotoxicity and undesirable side-effects. To this end, we have developed a nanotopography-mediated reverse uptake (NanoRU) delivery platform to demonstrate a simple and efficient technique for delivering siRNA into neural stem cells (NSCs). NanoRU consists of a self-assembled silica nanoparticle monolayer coated with extracellular matrix proteins and the desired siRNA. We use this technique to efficiently deliver siRNA against the transcription factor SOX9, which acts as a switch between neuronal and glial fate of NSCs. The knockdown of SOX9 enhanced the neuronal differentiation and decreased the glial differentiation of the NSCs. Our NanoRU platform demonstrates a novel application and the importance of nanotopography-mediated siRNA delivery into stem cells as an effective method for genetic manipulation.


Assuntos
Diferenciação Celular/genética , Técnicas de Silenciamento de Genes/métodos , Células-Tronco Neurais/metabolismo , RNA Interferente Pequeno/metabolismo , Fatores de Transcrição SOX9/genética , Animais , Linhagem Celular , Nanopartículas , Interferência de RNA , RNA Interferente Pequeno/administração & dosagem , Ratos , Dióxido de Silício
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA