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1.
Br J Haematol ; 204(6): 2194-2209, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38715390

RESUMO

This comprehensive guideline, developed by a representative group of UK-based medical experts specialising in haemoglobinopathies, addresses the management of conception and pregnancy in patients with thalassaemia. A systematic search of PubMed and EMBASE using specific keywords, formed the basis of the literature review. Key terms included "thalassaemia," "pregnancy," "Cooley's anaemia," "Mediterranean anaemia," and others, covering aspects such as fertility, iron burden and ultrasonography. The guideline underwent rigorous review by prominent organisations, including the Endocrine Society, the Royal College of Obstetricians and Gynaecologists (RCOG), the United Kingdom Thalassaemia Society and the British Society of Haematology (BSH) guideline writing group. Additional feedback was solicited from a sounding board of UK haematologists, ensuring a thorough and collaborative approach. The objective of the guideline is to equip healthcare professionals with precise recommendations for managing conception and pregnancy in patients with thalassaemia.


Assuntos
Complicações Hematológicas na Gravidez , Talassemia , Humanos , Gravidez , Feminino , Talassemia/terapia , Talassemia/complicações , Talassemia/diagnóstico , Complicações Hematológicas na Gravidez/terapia , Complicações Hematológicas na Gravidez/diagnóstico , Fertilização , Reino Unido
2.
Neuromuscul Disord ; 33(11): 835-844, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37932186

RESUMO

We conducted a systematic literature review and meta-analysis on the effectiveness of vitamin D supplementation in maintaining or restoring vitamin D levels in Duchenne muscular dystrophy. Due to a lack of randomised controlled trials, cross-sectional and retrospective and prospective cohort studies were taken as the best available evidence. Inclusion criteria included reporting mean serum vitamin D levels in a supplement-taking group. After screening 102 records; 13 were included in a narrative synthesis and eight of these in a meta-analysis. We show that current dosing regimens are preventing severe deficiency but are not effective at maintaining sufficient vitamin D levels within the Duchenne population. Despite high levels of daily vitamin D supplementation (>1000 International Units), at least 20 % of people with Duchenne remain vitamin D deficient. No significant association between dose and serum vitamin D levels was found (r2 = 0.3, p = 0.237). A meta-analysis of mean serum vitamin D levels across eight studies also revealed substantial variability in response to vitamin D supplementation and high heterogeneity (I2 = 99.59 %). These data could impact on an individual's risk and severity of osteoporosis and vertebral fractures.


Assuntos
Distrofia Muscular de Duchenne , Humanos , Distrofia Muscular de Duchenne/tratamento farmacológico , Estudos Retrospectivos , Estudos Prospectivos , Estudos Transversais , Vitamina D/uso terapêutico , Vitaminas , Suplementos Nutricionais
3.
bioRxiv ; 2023 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-36909469

RESUMO

Pseudomonas aeruginosa is intrinsically resistant to many classes of antibiotics, reflecting the restrictive nature of its outer membrane and the action of its numerous efflux systems. However, the dynamics of compound uptake, retention and efflux in this bacterium remain incompletely understood. Here, we exploited the sensor capabilities of a Z-nucleotide sensing riboswitch to create an experimental system able to identify physicochemical and structural properties of compounds that permeate the bacterial cell, avoid efflux, and perturb the folate cycle or de novo purine synthesis. In a first step, a collection of structurally diverse compounds enriched in antifolate drugs was screened for ZTP riboswitch reporter activity in efflux-deficient P. aeruginosa , allowing us to identify compounds that entered the cell and disrupted the folate pathway. These initial hits were then rescreened using isogenic efflux-proficient bacteria, allowing us to separate efflux substrates from efflux avoiders. We confirmed this categorization by measuring intracellular levels of select compounds in the efflux-deficient and - proficient strain using high resolution LC-MS. This simple yet powerful method, optimized for high throughput screening, enables the discovery of numerous permeable compounds that avoid efflux and paves the way for further refinement of the physicochemical and structural rules governing efflux in this multi-drug resistant Gram-negative pathogen. Importance: Treatment of Pseudomonas aeruginosa infections has become increasingly challenging. The development of novel antibiotics against this multi-drug resistant bacterium is a priority, but many drug candidates never achieve effective concentrations in the bacterial cell due due to its highly restrictive outer membrane and the action of multiple efflux pumps. Here, we develop a robust and simple reporter system in P. aeruginosa to screen chemical libraries and identify compounds that either enter the cell and remain inside, or enter the cell and are exported by efflux systems. This approach enables developing rules of compound uptake and retention in P. aeruginosa that will lead to more rational design of novel antibiotics.

4.
mSphere ; 8(2): e0006923, 2023 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-36946743

RESUMO

Pseudomonas aeruginosa is intrinsically resistant to many classes of antibiotics, reflecting the restrictive nature of its outer membrane and the action of its numerous efflux systems. However, the dynamics of compound uptake, retention, and efflux in this bacterium remain incompletely understood. Here, we exploited the sensor capabilities of a Z-nucleotide-sensing riboswitch to create an experimental system able to identify physicochemical and structural properties of compounds that permeate the bacterial cell, avoid efflux, and perturb the folate cycle or de novo purine synthesis. In the first step, a collection of structurally diverse compounds enriched in antifolate drugs was screened for ZTP (5-aminoimidazole-4-carboxamide riboside 5'-triphosphate) riboswitch reporter activity in efflux-deficient P. aeruginosa, allowing us to identify compounds that entered the cell and disrupted the folate pathway. These initial hits were then rescreened using isogenic efflux-proficient bacteria, allowing us to separate efflux substrates from efflux avoiders. We confirmed this categorization by measuring intracellular levels of select compounds in the efflux-deficient and -proficient strain using high-resolution liquid chromatography-mass spectrometry (LC-MS). This simple yet powerful method, optimized for high-throughput screening, enables the discovery of numerous permeable compounds that avoid efflux and paves the way for further refinement of the physicochemical and structural rules governing efflux in this multidrug-resistant Gram-negative pathogen. IMPORTANCE Treatment of Pseudomonas aeruginosa infections has become increasingly challenging. The development of novel antibiotics against this multidrug-resistant bacterium is a priority, but many drug candidates never achieve effective concentrations in the bacterial cell due to its highly restrictive outer membrane and the action of multiple efflux pumps. Here, we develop a robust and simple reporter system in P. aeruginosa to screen chemical libraries and identify compounds that either enter the cell and remain inside or enter the cell and are exported by efflux systems. This approach enables the development of rules of compound uptake and retention in P. aeruginosa that will lead to more rational design of novel antibiotics.


Assuntos
Pseudomonas aeruginosa , Riboswitch , Proteínas da Membrana Bacteriana Externa/genética , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/metabolismo , Farmacorresistência Bacteriana Múltipla/genética , Antibacterianos/farmacologia , Antibacterianos/metabolismo
5.
Anal Biochem ; 666: 115047, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36682579

RESUMO

Due to the emergence of multidrug resistant pathogens, it is imperative to identify new targets for antibiotic drug discovery. The S-adenosylhomocysteine (SAH) nucleosidase enzyme is a promising target for antimicrobial drug development due to its critical functions in multiple bacterial processes including recycling of toxic byproducts of S-adenosylmethionine (SAM)-mediated reactions and producing the precursor of the universal quorum sensing signal, autoinducer-2 (AI-2). Riboswitches are structured RNA elements typically used by bacteria to precisely monitor and respond to changes in essential bacterial processes, including metabolism. Natural riboswitches fused to a reporter gene can be exploited to detect changes in metabolism or in physiological signaling. We performed a high-throughput screen (HTS) using an SAH-riboswitch controlled ß-galactosidase reporter gene in Escherichia coli to discover small molecules that inhibit SAH recycling. We demonstrate that the assay strategy using SAH riboswitches to detect the effects of SAH nucleosidase inhibitors can quickly identify compounds that penetrate the barriers of Gram-negative bacterial cells and perturb pathways involving SAH.


Assuntos
Riboswitch , S-Adenosilmetionina/metabolismo , RNA/genética , Bactérias/genética , N-Glicosil Hidrolases/genética , N-Glicosil Hidrolases/metabolismo
6.
Hum Gene Ther ; 34(9-10): 439-448, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36453228

RESUMO

Duchenne muscular dystrophy (DMD) is caused by the lack of dystrophin, but many patients have rare revertant fibers that express dystrophin. The skeletal muscle pathology of DMD patients includes immune cell infiltration and inflammatory cascades. There are several strategies to restore dystrophin in skeletal muscles of patients, including exon skipping and gene therapy. There is some evidence that dystrophin restoration leads to a reduction in immune cells, but dystrophin epitopes expressed in revertant fibers or following genome editing, cell therapy, or microdystrophin delivery after adeno-associated viral gene therapy may elicit T cell production in patients. This may affect the efficacy of the therapeutic intervention, and potentially lead to serious adverse events. To confirm and extend previous studies, we performed annual enzyme- linked immunospot interferon-gamma assays on peripheral blood mononuclear cells from 77 pediatric boys with DMD recruited into a natural history study, 69 of whom (89.6%) were treated with corticosteroids. T cell responses to dystrophin were quantified using a total of 368 peptides spanning the entire dystrophin protein, organized into nine peptide pools. Peptide mapping pools were used to further localize the immune response in one positive patient. Six (7.8%) patients had a T cell-mediated immune response to dystrophin at at least one time point. All patients who had a positive result had been treated with corticosteroids, either prednisolone or prednisone. Our results show that ∼8% of DMD individuals in our cohort have a pre-existing T cell-mediated immune response to dystrophin, despite steroid treatment. Although these responses are relatively low level, this information should be considered a useful immunological baseline before undertaking clinical trials and future DMD studies. We further highlight the importance for a robust, reproducible standard operating procedure for collecting, storing, and shipping samples from multiple centers to minimize the number of inconclusive data.


Assuntos
Distrofia Muscular de Duchenne , Masculino , Humanos , Criança , Distrofia Muscular de Duchenne/genética , Distrofina/genética , Leucócitos Mononucleares/metabolismo , Linfócitos T/metabolismo , Músculo Esquelético/metabolismo
7.
Sci Rep ; 12(1): 3200, 2022 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-35217778

RESUMO

Alterations in the expression of the Duchenne muscular dystrophy (DMD) gene have been associated with the development, progression and survival outcomes of numerous cancers including tumours of the central nervous system. We undertook a detailed bioinformatic analysis of low-grade glioma (LGG) bulk RNAseq data to characterise the association between DMD expression and LGG survival outcomes. High DMD expression was significantly associated with poor survival in LGG with a difference in median overall survival between high and low DMD groups of over 7 years (P = < 0.0001). In a multivariate model, DMD expression remained significant (P = 0.02) and was an independent prognostic marker for LGG. The effect of DMD expression on overall survival was only apparent in isocitrate dehydrogenase (IDH) mutant cases where non-1p/19q co-deleted LGG patients could be further stratified into high/low DMD groups. Patients in the high DMD group had a median overall survival time almost halve that of the low DMD group. The expression of the individual DMD gene products Dp71, Dp71ab and Dp427m were also significantly associated with overall survival in LGG which have differential biological effects relevant to the pathogenesis of LGG. Differential gene expression and pathway analysis identifies dysregulated biological processes relating to ribosome biogenesis, synaptic signalling, neurodevelopment, morphogenesis and immune pathways. Genes spanning almost the entirety of chromosome 1p are upregulated in patients with high overall DMD, Dp71 and Dp427m expression which worsens survival outcomes for these patients. We confirmed dystrophin protein is variably expressed in LGG tumour tissue by immunohistochemistry and, overall, demonstrate that DMD expression has potential utility as an independent prognostic marker which can further stratify IDH mutant LGG to identify those at risk of poor survival. This knowledge may improve risk stratification and management of LGG.


Assuntos
Neoplasias Encefálicas , Glioma , Isocitrato Desidrogenase , Distrofia Muscular de Duchenne , Biomarcadores/metabolismo , Neoplasias Encefálicas/enzimologia , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologia , Expressão Gênica , Glioma/enzimologia , Glioma/genética , Glioma/patologia , Humanos , Isocitrato Desidrogenase/genética , Isocitrato Desidrogenase/metabolismo , Distrofia Muscular de Duchenne/enzimologia , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/patologia , Mutação , Gradação de Tumores , Prognóstico
8.
RNA Biol ; 19(1): 176-190, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35067193

RESUMO

RNA-based therapeutics have entered the mainstream with seemingly limitless possibilities to treat all categories of neurological disease. Here, common RNA-based drug modalities such as antisense oligonucleotides, small interfering RNAs, RNA aptamers, RNA-based vaccines and mRNA drugs are reviewed highlighting their current and potential applications. Rapid progress has been made across rare genetic diseases and neurodegenerative disorders, but safe and effective delivery to the brain remains a significant challenge for many applications. The advent of individualized RNA-based therapies for ultra-rare diseases is discussed against the backdrop of the emergence of this field into more common conditions such as Alzheimer's disease and ischaemic stroke. There remains significant untapped potential in the use of RNA-based therapeutics for behavioural disorders and tumours of the central nervous system; coupled with the accelerated development expected over the next decade, the true potential of RNA-based therapeutics to transform the therapeutic landscape in neurology remains to be uncovered.


Assuntos
Terapia Genética , Doenças do Sistema Nervoso/terapia , RNA/genética , RNA/uso terapêutico , Animais , Aptâmeros de Nucleotídeos , Gerenciamento Clínico , Suscetibilidade a Doenças , Regulação da Expressão Gênica , Terapia Genética/efeitos adversos , Terapia Genética/métodos , Humanos , Doenças do Sistema Nervoso/etiologia , RNA/química , Interferência de RNA , RNA Interferente Pequeno , Terapêutica com RNAi , Reparo Gênico Alvo-Dirigido
9.
Cell Oncol (Dordr) ; 44(1): 19-32, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33188621

RESUMO

BACKGROUND: Mutation of the Duchenne muscular dystrophy (DMD) gene causes Duchenne and Becker muscular dystrophy, degenerative neuromuscular disorders that primarily affect voluntary muscles. However, increasing evidence implicates DMD in the development of all major cancer types. DMD is a large gene with 79 exons that codes for the essential muscle protein dystrophin. Alternative promotor usage drives the production of several additional dystrophin protein products with roles that extend beyond skeletal muscle. The importance and function(s) of these gene products outside of muscle are not well understood. CONCLUSIONS: We highlight a clear role for DMD in the pathogenesis of several cancers, including sarcomas, leukaemia's, lymphomas, nervous system tumours, melanomas and various carcinomas. We note that the normal balance of DMD gene products is often disrupted in cancer. The short dystrophin protein Dp71 is, for example, typically maintained in cancer whilst the full-length Dp427 gene product, a likely tumour suppressor, is frequently inactivated in cancer due to a recurrent loss of 5' exons. Therefore, the ratio of short and long gene products may be important in tumorigenesis. In this review, we summarise the tumours in which DMD is implicated and provide a hypothesis for possible mechanisms of tumorigenesis, although the question of cause or effect may remain. We hope to stimulate further study into the potential role of DMD gene products in cancer and the development of novel therapeutics that target DMD.


Assuntos
Distrofina/genética , Distrofia Muscular de Duchenne/genética , Neoplasias/genética , Animais , Distrofina/química , Predisposição Genética para Doença , Humanos , Modelos Biológicos
10.
ACS Med Chem Lett ; 11(10): 1843-1847, 2020 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-33062162

RESUMO

Human Macrophage Migration Inhibitory Factor (MIF) is a trimeric cytokine implicated in a number of inflammatory and autoimmune diseases and cancer. We previously reported that the dye p425 (Chicago Sky Blue), which bound MIF at the interface of two MIF trimers covering the tautomerase and allosteric pockets, revealed a unique strategy to block MIF's pro-inflammatory activities. Structural liabilities, including the large size, precluded p425 as a medicinal chemistry lead for drug development. We report here a rational design strategy linking only the fragment of p425 that binds over the tautomerase pocket to the core of ibudilast, a known MIF allosteric site-specific inhibitor. The chimeric compound, termed L2-4048, was shown by X-ray crystallography to bind at the allosteric and tautomerase sites as anticipated. L2-4048 retained target binding and blocked MIF's tautomerase CD74 receptor binding, and pro-inflammatory activities. Our studies lay the foundation for the design and synthesis of smaller and more drug-like compounds that retain the MIF inhibitory properties of this chimera.

11.
Mol Neurobiol ; 57(3): 1748-1767, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31836945

RESUMO

Duchenne muscular dystrophy (DMD) is caused by frameshift mutations in the DMD gene that prevent the body-wide translation of its protein product, dystrophin. Besides a severe muscle phenotype, cognitive impairment and neuropsychiatric symptoms are prevalent. Dystrophin protein 71 (Dp71) is the major DMD gene product expressed in the brain and mutations affecting its expression are associated with the DMD neuropsychiatric syndrome. As with dystrophin in muscle, Dp71 localises to dystrophin-associated protein complexes in the brain. However, unlike in skeletal muscle; in the brain, Dp71 is alternatively spliced to produce many isoforms with differential subcellular localisations and diverse cellular functions. These include neuronal differentiation, adhesion, cell division and excitatory synapse organisation as well as nuclear functions such as nuclear scaffolding and DNA repair. In this review, we first describe brain involvement in DMD and the abnormalities observed in the DMD brain. We then review the gene expression, RNA processing and functions of Dp71. We review genotype-phenotype correlations and discuss emerging cellular/tissue evidence for the involvement of Dp71 in the neuropathophysiology of DMD. The literature suggests changes observed in the DMD brain are neurodevelopmental in origin and that their risk and severity is associated with a cumulative loss of distal DMD gene products such as Dp71. The high risk of neuropsychiatric syndromes in Duchenne patients warrants early intervention to achieve the best possible quality of life. Unravelling the function and pathophysiological significance of dystrophin in the brain has become a high research priority to inform the development of brain-targeting treatments for Duchenne.


Assuntos
Encéfalo/metabolismo , Distrofina/metabolismo , Distrofia Muscular de Duchenne/metabolismo , Animais , Expressão Gênica/fisiologia , Humanos , Sinapses/metabolismo
12.
PLoS One ; 13(10): e0204485, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30278058

RESUMO

BACKGROUND: Duchenne muscular dystrophy is a lethal disease caused by lack of dystrophin. Skipping of exons adjacent to out-of-frame deletions has proven to restore dystrophin expression in Duchenne patients. Exon 51 has been the most studied target in both preclinical and clinical settings and the availability of standardized procedures to quantify exon skipping would be advantageous for the evaluation of preclinical and clinical data. OBJECTIVE: To compare methods currently used to quantify antisense oligonucleotide-induced exon 51 skipping in the DMD transcript and to provide guidance about the method to use. METHODS: Six laboratories shared blinded RNA samples from Duchenne patient-derived muscle cells treated with different amounts of exon 51 targeting antisense oligonucleotide. Exon 51 skipping levels were quantified using five different techniques: digital droplet PCR, single PCR assessed with Agilent bioanalyzer, nested PCR with agarose gel image analysis by either ImageJ or GeneTools software and quantitative real-time PCR. RESULTS: Differences in mean exon skipping levels and dispersion around the mean were observed across the different techniques. Results obtained by digital droplet PCR were reproducible and showed the smallest dispersion. Exon skipping quantification with the other methods showed overestimation of exon skipping or high data variation. CONCLUSIONS: Our results suggest that digital droplet PCR was the most precise and quantitative method. The quantification of exon 51 skipping by Agilent bioanalyzer after a single round of PCR was the second-best choice with a 2.3-fold overestimation of exon 51 skipping levels compared to digital droplet PCR.


Assuntos
Distrofina/genética , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/metabolismo , Oligonucleotídeos Antissenso , Reação em Cadeia da Polimerase/métodos , Splicing de RNA , Linhagem Celular , Distrofina/metabolismo , Éxons , Humanos , Mioblastos/metabolismo
13.
Biol Methods Protoc ; 2(1): bpx009, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32161791

RESUMO

Photo cross-linking of proteins with short RNA oligomers is a classical method to study RNA-protein interactions that are implicated in many aspects of RNA metabolism and function. Most commonly, this involves the use of [γ-32P]-labeled RNA probes. Although very sensitive, these procedures are complicated by the safety issues associated with the use of radioisotopes. Here, we describe a modified UV cross-linking method using oligonucleotide probes end labelled with the infrared dye IRDye®800. After UV cross-linking, proteins are separated by SDS-PAGE and cross-linked products are visualized with the Odyssey® Infrared Imaging system. This end labelling approach provides a streamlined alternative to random labelling which reduces the efficiency of in-vitro transcription. End labelling is also independent of the length of the probe, thus facilitating quantitative comparisons. To validate the method, we have confirmed the binding of HuD to the 3'-UTR of the mRNA for the microtubule-associated protein tau, implicated in the pathogenesis of Alzheimer's disease. UV cross-linking of HuD with a labeled 21-mer probe was successfully performed using a recombinant purified glutathione-S-transferase-HuD fusion protein as well as with lysates from CHO cells transfected with HuD cDNA. UV cross-linking combined with infrared imaging offers a convenient and robust strategy to analyse RNA-protein interactions and their emerging importance in disease.

15.
Neurology ; 83(22): 2062-9, 2014 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-25355828

RESUMO

OBJECTIVE: We formed a multi-institution collaboration in order to compare dystrophin quantification methods, reach a consensus on the most reliable method, and report its biological significance in the context of clinical trials. METHODS: Five laboratories with expertise in dystrophin quantification performed a data-driven comparative analysis of a single reference set of normal and dystrophinopathy muscle biopsies using quantitative immunohistochemistry and Western blotting. We developed standardized protocols and assessed inter- and intralaboratory variability over a wide range of dystrophin expression levels. RESULTS: Results from the different laboratories were highly concordant with minimal inter- and intralaboratory variability, particularly with quantitative immunohistochemistry. There was a good level of agreement between data generated by immunohistochemistry and Western blotting, although immunohistochemistry was more sensitive. Furthermore, mean dystrophin levels determined by alternative quantitative immunohistochemistry methods were highly comparable. CONCLUSIONS: Considering the biological function of dystrophin at the sarcolemma, our data indicate that the combined use of quantitative immunohistochemistry and Western blotting are reliable biochemical outcome measures for Duchenne muscular dystrophy clinical trials, and that standardized protocols can be comparable between competent laboratories. The methodology validated in our study will facilitate the development of experimental therapies focused on dystrophin production and their regulatory approval.


Assuntos
Distrofina/análise , Pesquisa Translacional Biomédica/normas , Distrofina/genética , Humanos , Ciência de Laboratório Médico/métodos , Ciência de Laboratório Médico/normas , Distrofia Muscular de Duchenne/diagnóstico , Distrofia Muscular de Duchenne/genética , Variações Dependentes do Observador , Pesquisa Translacional Biomédica/métodos
16.
Acta Crystallogr D Biol Crystallogr ; 70(Pt 7): 1922-33, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25004969

RESUMO

Clostridium difficile, a Gram-positive, spore-forming anaerobic bacterium, is the leading cause of infectious diarrhea among hospitalized patients. C. difficile is frequently associated with antibiotic treatment, and causes diseases ranging from antibiotic-associated diarrhea to life-threatening pseudomembranous colitis. The severity of C. difficile infections is exacerbated by the emergence of hypervirulent and multidrug-resistant strains, which are difficult to treat and are often associated with increased mortality rates. Alanine racemase (Alr) is a pyridoxal-5'-phosphate (PLP)-dependent enzyme that catalyzes the reversible racemization of L- and D-alanine. Since D-alanine is an essential component of the bacterial cell-wall peptidoglycan, and there are no known Alr homologs in humans, this enzyme is being tested as an antibiotic target. Cycloserine is an antibiotic that inhibits Alr. In this study, the catalytic properties and crystal structures of recombinant Alr from the virulent and multidrug-resistant C. difficile strain 630 are presented. Three crystal structures of C. difficile Alr (CdAlr), corresponding to the complex with PLP, the complex with cycloserine and a K271T mutant form of the enzyme with bound PLP, are presented. The structures are prototypical Alr homodimers with two active sites in which the cofactor PLP and cycloserine are localized. Kinetic analyses reveal that the K271T mutant CdAlr has the highest catalytic constants reported to date for any Alr. Additional studies are needed to identify the basis for the high catalytic activity. The structural and activity data presented are first steps towards using CdAlr for the development of structure-based therapeutics for C. difficile infections.


Assuntos
Alanina Racemase/química , Clostridioides difficile/enzimologia , Farmacorresistência Bacteriana Múltipla , Sequência de Aminoácidos , Cromatografia em Gel , Clostridioides difficile/efeitos dos fármacos , Cristalografia por Raios X , Dimerização , Dados de Sequência Molecular , Conformação Proteica , Proteínas Recombinantes/química , Homologia de Sequência de Aminoácidos
17.
Brain Res ; 1584: 22-7, 2014 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-24389033

RESUMO

The microtubule-associated protein tau is predominantly localized in the axonal compartment over the entire length of the axon in neurons. The mechanisms responsible for the localization of tau in axons at long distance from the cell body are not properly understood. Using fluorescence in situ hybridization, we show that tau mRNA is present in the central and distal parts of the axons of cultured rat cortical neurons. Axonal tau mRNA is associated with granules which are distributed throughout the entire length of the axon, including the growth cone. We also show that tau mRNA-containing axonal particles are associated with elongation factor 1A, a component of the protein translation machinery. The presence of tau mRNA in axons might be at least part of the process by which tau is localized to distal axons.


Assuntos
Axônios/metabolismo , Córtex Cerebral/metabolismo , Fator 1 de Elongação de Peptídeos/análise , RNA Mensageiro/análise , Proteínas tau/análise , Animais , Células Cultivadas , Grânulos Citoplasmáticos/metabolismo , Ratos , Ratos Sprague-Dawley , Proteínas tau/genética
18.
JAMA Neurol ; 71(1): 32-40, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24217213

RESUMO

IMPORTANCE: In Duchenne muscular dystrophy (DMD), the reading frame of an out-of-frame DMD deletion can be repaired by antisense oligonucleotide (AO)-mediated exon skipping. This creates a shorter dystrophin protein, similar to those expressed in the milder Becker muscular dystrophy (BMD). The skipping of some exons may be more efficacious than others. Patients with exon 44 or 45 skippable deletions (AOs in clinical development) have a less predictable phenotype than those skippable for exon 51, a group in advanced clinical trials. A way to predict the potential of AOs is the study of patients with BMD who have deletions that naturally mimic those that would be achieved by exon skipping. OBJECTIVE: To quantify dystrophin messenger RNA (mRNA) and protein expression in patients with DMD deletions treatable by, or mimicking, exon 44 or 45 skipping. DESIGN, SETTING, AND PARTICIPANTS: Retrospective study of nondystrophic controls (n = 2), patients with DMD (n = 5), patients with intermediate muscular dystrophy (n = 3), and patients with BMD (n = 13) at 4 university-based academic centers and pediatric hospitals. Biochemical analysis of existing muscle biopsies was correlated with the severity of the skeletal muscle phenotype. MAIN OUTCOMES AND MEASURES: Dystrophin mRNA and protein expression. RESULTS: Patients with DMD who have out-of-frame deletions skippable for exon 44 or 45 had an elevated number of revertant and trace dystrophin expression (approximately 19% of control, using quantitative immunohistochemistry) with 4 of 9 patients presenting with an intermediate muscular dystrophy phenotype (3 patients) or a BMD-like phenotype (1 patient). Corresponding in-frame deletions presented with predominantly mild BMD phenotypes and lower dystrophin levels (approximately 42% of control) than patients with BMD modeling exon 51 skipping (approximately 80% of control). All 12 patients with in-frame deletions had a stable transcript compared with 2 of 9 patients with out-of-frame deletions (who had intermediate muscular dystrophy and BMD phenotypes). CONCLUSIONS AND RELEVANCE: Exon 44 or 45 skipping will likely yield lower levels of dystrophin than exon 51 skipping, although the resulting protein is functional enough to often maintain a mild BMD phenotype. Dystrophin transcript stability is an important indicator of dystrophin expression, and transcript instability in DMD compared with BMD should be explored as a potential biomarker of response to AOs. This study is beneficial for the planning, execution, and analysis of clinical trials for exon 44 and 45 skipping.


Assuntos
Distrofina/genética , Éxons/genética , Distrofias Musculares/genética , Distrofia Muscular de Duchenne/genética , RNA Mensageiro/genética , Deleção de Sequência/genética , Adolescente , Adulto , Biomarcadores/metabolismo , Criança , Pré-Escolar , Distrofina/biossíntese , Humanos , Masculino , Músculo Esquelético/química , Músculo Esquelético/patologia , Distrofias Musculares/classificação , Distrofias Musculares/patologia , Distrofia Muscular de Duchenne/metabolismo , Distrofia Muscular de Duchenne/patologia , Oligonucleotídeos Antissenso/genética , Fenótipo , Estudos Retrospectivos , Adulto Jovem
19.
Biochem Pharmacol ; 86(2): 222-30, 2013 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-23680030

RESUMO

The genus Mycobacterium includes non-pathogenic species such as M. smegmatis, and pathogenic species such as M. tuberculosis, the causative agent of tuberculosis (TB). Treatment of TB requires a lengthy regimen of several antibiotics, whose effectiveness has been compromised by the emergence of resistant strains. New antibiotics that can shorten the treatment course and those that have not been compromised by bacterial resistance are needed. In this study, we report that thiadiazolidinones, a relatively little-studied heterocyclic class, inhibit the activity of mycobacterial alanine racemase, an essential enzyme that converts l-alanine to d-alanine for peptidoglycan synthesis. Twelve members of the thiadiazolidinone family were evaluated for inhibition of M. tuberculosis and M. smegmatis alanine racemase activity and bacterial growth. Thiadiazolidinones inhibited M. tuberculosis and M. smegmatis alanine racemases to different extents with 50% inhibitory concentrations (IC50) ranging from <0.03 to 28µM and 23 to >150µM, respectively. The compounds also inhibited the growth of these bacteria, including multidrug resistant strains of M. tuberculosis. The minimal inhibitory concentrations (MIC) for drug-susceptible M. tuberculosis and M. smegmatis ranged from 6.25µg/ml to 100µg/ml, and from 1.56 to 6.25µg/ml for drug-resistant M. tuberculosis. The in vitro activities of thiadiazolidinones suggest that this family of compounds might represent starting points for medicinal chemistry efforts aimed at developing novel antimycobacterial agents.


Assuntos
Alanina Racemase/antagonistas & inibidores , Mycobacterium smegmatis/efeitos dos fármacos , Mycobacterium tuberculosis/efeitos dos fármacos , Tiadiazóis/farmacologia , Alanina Racemase/química , Alanina Racemase/metabolismo , Sequência de Aminoácidos , Catálise , Dados de Sequência Molecular , Mycobacterium smegmatis/enzimologia , Mycobacterium tuberculosis/enzimologia , Homologia de Sequência de Aminoácidos , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
20.
Popul Health Manag ; 16(2): 99-106, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23405873

RESUMO

Value-based insurance design (VBID) initiatives have been associated with modest improvements in adherence based on evaluations of administrative claims data. The objective of this prospective cohort study was to report the patient-centered outcomes of a VBID program that eliminated co-payments for diabetes-related medications and supplies for employees and dependents with diabetes at a large health system. The authors compared self-reported values of medication adherence, cost-related nonadherence, health status, and out-of-pocket health care costs for patients before and 1 year after program implementation. Clinical metrics and satisfaction with the program also are reported. In all, 188 patients completed the follow-up evaluation. Overall, patients reported a significant reduction in monthly out-of-pocket costs (P<0.001), which corresponded to a significant reduction in cost-related nonadherence from 41% to 17.5% (P<0.001). Self-reported medication adherence increased for hyperglycemic medications (P=0.011), but there were no apparent changes in glycemic control. Overall, 89% of participants agreed that the program helped them take better care of their diabetes. The authors found that a VBID program for employees and dependents with diabetes was associated with self-reported reductions in cost-related nonadherence and improvements in medication adherence. Importantly, the program was associated with high levels of satisfaction among participants and strongly perceived by participants to facilitate medication utilization and self-management for diabetes. These findings suggest that VBID programs can accomplish the anticipated goals for medication utilization and are highly regarded by participants. Patient-centered outcomes should be included in VBID evaluations to allow decision makers to determine the true impact of VBID programs on participants.


Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 2/tratamento farmacológico , Planos de Assistência de Saúde para Empregados , Assistência Centrada no Paciente , Aquisição Baseada em Valor , Adolescente , Adulto , Delaware , Feminino , Financiamento Pessoal , Humanos , Masculino , Adesão à Medicação , Pessoa de Meia-Idade , Avaliação de Resultados em Cuidados de Saúde , Estudos Prospectivos , Inquéritos e Questionários , Adulto Jovem
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